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Sample records for continuous packed-bed reactor

  1. Continuous thermophilic biohydrogen production in packed bed reactor

    International Nuclear Information System (INIS)

    Roy, Shantonu; Vishnuvardhan, M.; Das, Debabrata

    2014-01-01

    Highlights: • Continuous H 2 production in whole cell immobilized system was compared with CSTR. • Suitability of environment friendly support matrix for immobilization of whole cells was explored. • Pack bed reactor showed higher stability as compared to CSTR at lower HRTs. • Flow cytometry study showed the influence of recycle ratio on viability of cells. • Novel approach to find out the effect of NADH/NAD + ratio during H 2 production. - Abstract: The present research work deals with the performance of packed bed reactor for continuous H 2 production using cane molasses as a carbon source. Maximum H 2 production rate of 1.7 L L −1 h −1 was observed at a dilution rate and recycle ratio of 0.8 h −1 and 0.6, respectively which was corresponding to the lowest NADH/NAD + ratio. This suggests that the utilization of NADH pool for H 2 and metabolite production might lead to decrement in NADH/NAD + ratio. Thus NADH/NAD + ratio show inverse relation with hydrogen production. The substrate degradation kinetics was investigated as a function of flow rate considering the external film diffusion model. At a flow rate of 245 mL h −1 , the contribution of external film mass transfer coefficient and first order substrate degradation constant were 55.4% and 44.6% respectively. Recycle ratio of 0.6 improved the hydrogen production rates by 9%. The viable cell count was directly proportional to the recycle ratio (within the range 0.1–0.6). Taguchi design showed the significant influence of the feed pH on continuous H 2 production followed by dilution rate and recycle ratio. Thus environmentally friendly and cheaper solid matrix like coconut coir could be efficiently used for thermophilic continuous hydrogen production

  2. Butanol production by Clostridium acetobutylicum in a continuous packed bed reactor.

    Science.gov (United States)

    Napoli, Fabio; Olivieri, Giuseppe; Russo, Maria Elena; Marzocchella, Antonio; Salatino, Piero

    2010-06-01

    In this study, we report on a butanol production process by immobilized Clostridium acetobutylicum in a continuous packed bed reactor (PBR) using Tygon rings as a carrier. The medium was a solution of lactose (15-30 g/L) and yeast extract (3 g/L) to emulate the cheese whey, an abundant lactose-rich wastewater. The reactor was operated under controlled conditions with respect to the pH and to the dilution rate. The pH and the dilution rate ranged between 4 and 5, the dilution rate between 0.54 and 2.4 h(-1) (2.5 times the maximum specific growth rate assessed for suspended cells). The optimal performance of the reactor was recorded at a dilution rate of 0.97 h(-1): the butanol productivity was 4.4 g/Lh and the selectivity of solvent in butanol was 88%(w).

  3. Evaluation of Packed-Bed Reactor and Continuous Stirred Tank Reactor for the Production of Colchicine Derivatives

    OpenAIRE

    Dubey, Kashyap Kumar; Kumar, Dhirendra; Kumar, Punit; Haque, Shafiul; Jawed, Arshad

    2013-01-01

    Bioconversion of colchicine into its pharmacologically active derivative 3-demethylated colchicine (3-DMC) mediated by P450BM3 enzyme is an economic and promising strategy for the production of this inexpensive and potent anticancer drug. Continuous stirred tank reactor (CSTR) and packed-bed reactor (PBR) of 3 L and 2 L total volumes were compared for the production of 3-demethylated colchicine (3-DMC) a colchicine derivative using Bacillus megaterium MTCC*420 under aerobic conditions. Statis...

  4. Continuous Packed Bed Reactor with Immobilized β-Galactosidase for Production of Galactooligosaccharides (GOS

    Directory of Open Access Journals (Sweden)

    Barbara Rodriguez-Colinas

    2016-11-01

    Full Text Available The β-galactosidase from Bacillus circulans was covalently attached to aldehyde-activated (glyoxal agarose beads and assayed for the continuous production of galactooligosaccharides (GOS in a packed-bed reactor (PBR. The immobilization was fast (1 h and the activity of the resulting biocatalyst was 97.4 U/g measured with o-nitrophenyl-β-d-galactopyranoside (ONPG. The biocatalyst showed excellent operational stability in 14 successive 20 min reaction cycles at 45 °C in a batch reactor. A continuous process for GOS synthesis was operated for 213 h at 0.2 mL/min and 45 °C using 100 g/L of lactose as a feed solution. The efficiency of the PBR slightly decreased with time; however, the maximum GOS concentration (24.2 g/L was obtained after 48 h of operation, which corresponded to 48.6% lactose conversion and thus to maximum transgalactosylation activity. HPAEC-PAD analysis showed that the two major GOS were the trisaccharide Gal-β(1→4-Gal-β(1→4-Glc and the tetrasaccharide Gal-β(1→4-Gal-β(1→4-Gal-β(1→4-Glc. The PBR was also assessed in the production of GOS from milk as a feed solution. The stability of the bioreactor was satisfactory during the first 8 h of operation; after that, a decrease in the flow rate was observed, probably due to partial clogging of the column. This work represents a step forward in the continuous production of GOS employing fixed-bed reactors with immobilized β-galactosidases.

  5. Butanol production by bioconversion of cheese whey in a continuous packed bed reactor.

    Science.gov (United States)

    Raganati, F; Olivieri, G; Procentese, A; Russo, M E; Salatino, P; Marzocchella, A

    2013-06-01

    Butanol production by Clostridium acetobutylicum DSM 792 fermentation was investigated. Unsupplemented cheese whey was adopted as renewable feedstock. The conversion was successfully carried out in a biofilm packed bed reactor (PBR) for more than 3 months. The PBR was a 4 cm ID, 16 cm high glass tube with a 8 cm bed of 3mm Tygon rings, as carriers. It was operated at the dilution rate between 0.4h(-1) and 0.94 h(-1). The cheese whey conversion process was characterized in terms of metabolites production (butanol included), lactose conversion and biofilm mass. Under optimized conditions, the performances were: butanol productivity 2.66 g/Lh, butanol concentration 4.93 g/L, butanol yield 0.26 g/g, butanol selectivity of the overall solvents production 82 wt%. Copyright © 2013 Elsevier Ltd. All rights reserved.

  6. Continuous production of lipase-catalyzed biodiesel in a packed-bed reactor: optimization and enzyme reuse study.

    Science.gov (United States)

    Chen, Hsiao-Ching; Ju, Hen-Yi; Wu, Tsung-Ta; Liu, Yung-Chuan; Lee, Chih-Chen; Chang, Cheng; Chung, Yi-Lin; Shieh, Chwen-Jen

    2011-01-01

    An optimal continuous production of biodiesel by methanolysis of soybean oil in a packed-bed reactor was developed using immobilized lipase (Novozym 435) as a catalyst in a tert-butanol solvent system. Response surface methodology (RSM) and Box-Behnken design were employed to evaluate the effects of reaction temperature, flow rate, and substrate molar ratio on the molar conversion of biodiesel. The results showed that flow rate and temperature have significant effects on the percentage of molar conversion. On the basis of ridge max analysis, the optimum conditions were as follows: flow rate 0.1 mL/min, temperature 52.1°C, and substrate molar ratio 1 : 4. The predicted and experimental values of molar conversion were 83.31 ± 2.07% and 82.81 ± .98%, respectively. Furthermore, the continuous process over 30 days showed no appreciable decrease in the molar conversion. The paper demonstrates the applicability of using immobilized lipase and a packed-bed reactor for continuous biodiesel synthesis.

  7. Continuous Production of Lipase-Catalyzed Biodiesel in a Packed-Bed Reactor: Optimization and Enzyme Reuse Study

    Directory of Open Access Journals (Sweden)

    Hsiao-Ching Chen

    2011-01-01

    Full Text Available An optimal continuous production of biodiesel by methanolysis of soybean oil in a packed-bed reactor was developed using immobilized lipase (Novozym 435 as a catalyst in a tert-butanol solvent system. Response surface methodology (RSM and Box-Behnken design were employed to evaluate the effects of reaction temperature, flow rate, and substrate molar ratio on the molar conversion of biodiesel. The results showed that flow rate and temperature have significant effects on the percentage of molar conversion. On the basis of ridge max analysis, the optimum conditions were as follows: flow rate 0.1 mL/min, temperature 52.1∘C, and substrate molar ratio 1 : 4. The predicted and experimental values of molar conversion were 83.31±2.07% and 82.81±.98%, respectively. Furthermore, the continuous process over 30 days showed no appreciable decrease in the molar conversion. The paper demonstrates the applicability of using immobilized lipase and a packed-bed reactor for continuous biodiesel synthesis.

  8. Optimization of lipase-catalyzed biodiesel by isopropanolysis in a continuous packed-bed reactor using response surface methodology.

    Science.gov (United States)

    Chang, Cheng; Chen, Jiann-Hwa; Chang, Chieh-Ming J; Wu, Tsung-Ta; Shieh, Chwen-Jen

    2009-10-31

    Isopropanolysis reactions were performed using triglycerides with immobilized lipase in a solvent-free environment. This study modeled the degree of isopropanolysis of soybean oil in a continuous packed-bed reactor when Novozym 435 was used as the biocatalyst. Response surface methodology (RSM) and three-level-three-factor Box-Behnken design were employed to evaluate the effects of synthesis parameters, reaction temperature ( degrees C), flow rate (mL/min) and substrate molar ratio of isopropanol to soybean oil, on the percentage molar conversion of biodiesel by transesterification. The results show that flow rate and temperature have a significant effect on the percentage of molar conversion. On the basis of ridge max analysis, the optimum conditions for synthesis were as follows: flow rate 0.1 mL/min, temperature 51.5 degrees C and substrate molar ratio 1:4.14. The predicted value was 76.62+/-1.52% and actual experimental value was 75.62+/-0.81% molar conversion. Moreover, continuous enzymatic process for seven days did not show any appreciable decrease in the percent of molar conversion (75%). This work demonstrates the applicability of lipase catalysis to prepare isopropyl esters by transesterification in solvent-free system with a continuous packed-bed reactor for industrial production.

  9. Simple models for the continuous aerobic biodegradation of phenol in a packed bed reactor

    Directory of Open Access Journals (Sweden)

    Andrew Mark Gerrard

    2006-07-01

    Full Text Available This paper proposes the use of a preliminary, phenol removal step to reduce peak loads arriving at a conventional effluent plant. A packed bed reactor (PBR using polyurethane foam, porous glass and also cocoa fibres as the inert support material was used. Experiments have been carried out where the flow-rates, plus inlet and outlet phenol concentrations were measured. A simple, plug-flow model is proposed to represent the results. Zero, first order, Monod and inhibited kinetics rate equations were evaluated. It was found that the Monod model gave the best fit to the experimental data and allowed linear graphs to be plotted. The Monod saturation constant, K, is approximately 50 g m-3, and ka is around 900 s-1.Este artigo propõe o uso de uma etapa preliminar de remoção de fenol para redução de picos de carga na entrada de sistemas convencionais de tratamento de efluentes. Um reator de leito fixo (RLF foi usado, tendo como suportes inertes espuma de poliuretano, vidro poroso e também fibras de coco. Nos experimentos foram controladas a vazão e as concentrações de fenol de entrada e saída. Um simples modelo plug-flow é proposto para representar os resultados. Cinéticas de zero e primeira ordens, Monod e de inibição foram avaliadas. Foi verificado que o modelo de Monod foi o que melhor se ajustou aos dados experimentais, permitindo que gráficos lineares fossem traçados. A constante saturação de Monod, K, é de aproximadamente 50 g m-3 e ka em torno de 900 s-1.

  10. Enzymatic interesterification of butterfat with rapeseed oil in a continuous packed bed reactor

    DEFF Research Database (Denmark)

    Rønne, Torben Harald; Yang, Tiankui; Mu, Huiling

    2005-01-01

    , whereafter it dramatically decreased over the next 10 days to an activity level of 40%. In general, the study shows no significant difference for butterfat interesterification in terms of enzyme behavior from normal vegetable oils and fats even though it contains short-chain fatty acids and cholesterol......Lipase-catalyzed interesterification of butterfat blended with rapeseed oil (70/30, w/w) was investigated both in batch and in continuous reactions. Six commercially available immobilized lipases were screened in batch experiments, and the lipases, Lipozyme TL IM and Lipozyme RM IM, were chosen...

  11. Modeling the methanolysis of triglyceride catalyzed by immobilized lipase in a continuous-flow packed-bed reactor

    International Nuclear Information System (INIS)

    Tran, Dang-Thuan; Lin, Yi-Jan; Chen, Ching-Lung; Chang, Jo-Shu

    2014-01-01

    Highlights: • A Burkholderia lipase was immobilized on alkyl-grafted celite carriers. • Celite-alkyl-lipase catalyzed the methanolysis of triglyceride in packed-bed reactor. • The kinetics of the enzymatic transesterification follows Ping Pong Bi Bi mechanism. • Models were developed to discuss the mass transfer and enzyme kinetics in the PBR. - Abstract: A Burkholderia lipase was immobilized on celite grafted with long alkyl groups. The immobilized lipase-catalyzed methanolysis of sunflower oil in a packed-bed reactor (PBR) follows the Ping Pong Bi Bi mechanism. The external mass transfer and enzymatic reaction that simultaneously occurred in the PBR were investigated via the mathematical models. The overall biodiesel production in the PBR was verified to work in an enzymatic reaction-limited regime. Triglyceride conversion and biodiesel yield were higher under a lower reactant feeding rate, while a larger amount of biocatalyst would be required to achieve the designated conversion rate if a higher reactant feeding rate was employed. The PBR can achieve nearly complete conversion of triglyceride at a biocatalyst bed height of 60 cm (ca. 29 g biocatalyst) and a flow rate of 0.1 ml min −1 , whereas the biodiesel yield was lower than 67%, probably due to the positional specificity of Burkholderia lipase and the accumulation of glycerol

  12. Hydrodynamics of multi-phase packed bed micro-reactors

    NARCIS (Netherlands)

    Márquez Luzardo, N.M.

    2010-01-01

    Why to use packed bed micro-reactors for catalyst testing? Miniaturized packed bed reactors have a large surface-to-volume ratio at the reactor and particle level that favors the heat- and mass-transfer processes at all scales (intra-particle, inter-phase and inter-particle or reactor level). If the

  13. Continuous adsorption and biotransformation of micropollutants by granular activated carbon-bound laccase in a packed-bed enzyme reactor.

    Science.gov (United States)

    Nguyen, Luong N; Hai, Faisal I; Dosseto, Anthony; Richardson, Christopher; Price, William E; Nghiem, Long D

    2016-06-01

    Laccase was immobilized on granular activated carbon (GAC) and the resulting GAC-bound laccase was used to degrade four micropollutants in a packed-bed column. Compared to the free enzyme, the immobilized laccase showed high residual activities over a broad range of pH and temperature. The GAC-bound laccase efficiently removed four micropollutants, namely, sulfamethoxazole, carbamazepine, diclofenac and bisphenol A, commonly detected in raw wastewater and wastewater-impacted water sources. Mass balance analysis showed that these micropollutants were enzymatically degraded following adsorption onto GAC. Higher degradation efficiency of micropollutants by the immobilized compared to free laccase was possibly due to better electron transfer between laccase and substrate molecules once they have adsorbed onto the GAC surface. Results here highlight the complementary effects of adsorption and enzymatic degradation on micropollutant removal by GAC-bound laccase. Indeed laccase-immobilized GAC outperformed regular GAC during continuous operation of packed-bed columns over two months (a throughput of 12,000 bed volumes). Copyright © 2016 Elsevier Ltd. All rights reserved.

  14. Enzymatic synthesis of farnesyl laurate in organic solvent: initial water activity, kinetics mechanism, optimization of continuous operation using packed bed reactor and mass transfer studies.

    Science.gov (United States)

    Rahman, N K; Kamaruddin, A H; Uzir, M H

    2011-08-01

    The influence of water activity and water content was investigated with farnesyl laurate synthesis catalyzed by Lipozyme RM IM. Lipozyme RM IM activity depended strongly on initial water activity value. The best results were achieved for a reaction medium with an initial water activity of 0.11 since it gives the best conversion value of 96.80%. The rate constants obtained in the kinetics study using Ping-Pong-Bi-Bi and Ordered-Bi-Bi mechanisms with dead-end complex inhibition of lauric acid were compared. The corresponding parameters were found to obey the Ordered-Bi-Bi mechanism with dead-end complex inhibition of lauric acid. Kinetic parameters were calculated based on this model as follows: V (max) = 5.80 mmol l(-1) min(-1) g enzyme(-1), K (m,A) = 0.70 mmol l(-1) g enzyme(-1), K (m,B) = 115.48 mmol l(-1) g enzyme(-1), K (i) = 11.25 mmol l(-1) g enzyme(-1). The optimum conditions for the esterification of farnesol with lauric acid in a continuous packed bed reactor were found as the following: 18.18 cm packed bed height and 0.9 ml/min substrate flow rate. The optimum molar conversion of lauric acid to farnesyl laurate was 98.07 ± 0.82%. The effect of mass transfer in the packed bed reactor has also been studied using two models for cases of reaction limited and mass transfer limited. A very good agreement between the mass transfer limited model and the experimental data obtained indicating that the esterification in a packed bed reactor was mass transfer limited.

  15. Optimization of a packed bed reactor for liquid waste treatment

    International Nuclear Information System (INIS)

    Schmidt, C.A.; Brower, M.J.; Coogan, J.J.; Tennant, R.A.

    1993-01-01

    The authors describe an optimization study of a packed bed reactor (PBR), developed for the treatment of hazardous liquid wastes. The focus is on the destruction of trichloroethylene (TCE). The PBR technology offers many distinct advantages over other processes: simple design, high destruction rates (99.99%), low costs, ambient pressure operation, easy maintenance and scaleability. The cost effectiveness, optimal operating parameters and scaleability were determined. As a second stage of treatment, a silent discharge plasma (SDP) reactor was installed to further treat offgases from the PBR. A primary advantage of this system is closed loop operation, where exhaust gases are continuously recycled and not released into the atmosphere

  16. Performance Study of Chromium (VI Removal in Presence of Phenol in a Continuous Packed Bed Reactor by Escherichia coli Isolated from East Calcutta Wetlands

    Directory of Open Access Journals (Sweden)

    Bhaswati Chakraborty

    2013-01-01

    Full Text Available Organic pollutants, like phenol, along with heavy metals, like chromium, are present in various industrial effluents that pose serious health hazard to humans. The present study looked at removal of chromium (VI in presence of phenol in a counter-current continuous packed bed reactor packed with E. coli cells immobilized on clay chips. The cells removed 85% of 500 mg/L of chromium (VI from MS media containing glucose. Glucose was then replaced by 500 mg/L phenol. Temperature and pH of the MS media prior to addition of phenol were 30°C and 7, respectively. Hydraulic retention times of phenol- and chromium (VI-containing synthetic media and air flow rates were varied to study the removal efficiency of the reactor system. Then temperature conditions of the reactor system were varied from 10°C to 50°C, the optimum being 30°C. The pH of the media was varied from pH 1 to pH 12, and the optimum pH was found to be 7. The maximum removal efficiency of 77.7% was achieved for synthetic media containing phenol and chromium (VI in the continuous reactor system at optimized conditions, namely, hydraulic retention time at 4.44 hr, air flow rate at 2.5 lpm, temperature at 30°C, and pH at 7.

  17. Performance Study of Chromium (VI) Removal in Presence of Phenol in a Continuous Packed Bed Reactor by Escherichia coli Isolated from East Calcutta Wetlands

    Science.gov (United States)

    Chakraborty, Bhaswati; Indra, Suvendu; Hazra, Ditipriya; Betai, Rupal; Ray, Lalitagauri; Basu, Srabanti

    2013-01-01

    Organic pollutants, like phenol, along with heavy metals, like chromium, are present in various industrial effluents that pose serious health hazard to humans. The present study looked at removal of chromium (VI) in presence of phenol in a counter-current continuous packed bed reactor packed with E. coli cells immobilized on clay chips. The cells removed 85% of 500 mg/L of chromium (VI) from MS media containing glucose. Glucose was then replaced by 500 mg/L phenol. Temperature and pH of the MS media prior to addition of phenol were 30°C and 7, respectively. Hydraulic retention times of phenol- and chromium (VI)-containing synthetic media and air flow rates were varied to study the removal efficiency of the reactor system. Then temperature conditions of the reactor system were varied from 10°C to 50°C, the optimum being 30°C. The pH of the media was varied from pH 1 to pH 12, and the optimum pH was found to be 7. The maximum removal efficiency of 77.7% was achieved for synthetic media containing phenol and chromium (VI) in the continuous reactor system at optimized conditions, namely, hydraulic retention time at 4.44 hr, air flow rate at 2.5 lpm, temperature at 30°C, and pH at 7. PMID:24073400

  18. Packed Bed Reactor Technology for Chemical-Looping Combustion

    NARCIS (Netherlands)

    Noorman, S.; Sint Annaland, van M.; Kuipers, J.A.M.

    2007-01-01

    Chemical-looping combustion (CLC) has emerged as an alternative for conventional power production processes to intrinsically integrate power production and CO2 capture. In this work a new reactor concept for CLC is proposed, based on dynamically operated packed bed reactors. With analytical

  19. Continuous preparation of nanoscale zero-valent iron using impinging stream-rotating packed bed reactor and their application in reduction of nitrobenzene

    Science.gov (United States)

    Jiao, Weizhou; Qin, Yuejiao; Luo, Shuai; Feng, Zhirong; Liu, Youzhi

    2017-02-01

    Nanoscale zero-valent iron (nZVI) was continuously prepared by high-gravity reaction precipitation through a novel impinging stream-rotating packed bed (IS-RPB). Reactant solutions of FeSO4 and NaBH4 were conducted into the IS-RPB with flow rates of 60 L/h and rotating speed of 1000 r/min for the preparation of nZVI. As-prepared nZVI obtained by IS-RPB were quasi-spherical morphology and almost uniformly distributed with a particle size of 10-20 nm. The reactivity of nZVI was estimated by the degradation of 100 ml nitrobenzene (NB) with initial concentration of 250 mg/L. The optimum dosage of nZVI obtained by IS-RPB was 4.0 g/L as the NB could be completely removed within 10 min, which reduced 20% compared with nZVI obtained by stirred tank reactor (STR). The reduction of NB and production of aniline (AN) followed pseudo-first-order kinetics, and the pseudo-first-order rate constants were 0.0147 and 0.0034 s-1, respectively. Furthermore, the as-prepared nZVI using IS-RPB reactor in this work can be used within a relatively wide range pH of 1-9.

  20. Continuous preparation of nanoscale zero-valent iron using impinging stream-rotating packed bed reactor and their application in reduction of nitrobenzene

    Energy Technology Data Exchange (ETDEWEB)

    Jiao, Weizhou, E-mail: jwz0306@126.com; Qin, Yuejiao [North University of China, Shanxi Province Key Laboratory of Higee-Oriented Chemical Engineering (China); Luo, Shuai [Virginia Polytechnic Institute and State University, Department of Civil and Environmental Engineering (United States); Feng, Zhirong; Liu, Youzhi [North University of China, Shanxi Province Key Laboratory of Higee-Oriented Chemical Engineering (China)

    2017-02-15

    Nanoscale zero-valent iron (nZVI) was continuously prepared by high-gravity reaction precipitation through a novel impinging stream-rotating packed bed (IS-RPB). Reactant solutions of FeSO{sub 4} and NaBH{sub 4} were conducted into the IS-RPB with flow rates of 60 L/h and rotating speed of 1000 r/min for the preparation of nZVI. As-prepared nZVI obtained by IS-RPB were quasi-spherical morphology and almost uniformly distributed with a particle size of 10–20 nm. The reactivity of nZVI was estimated by the degradation of 100 ml nitrobenzene (NB) with initial concentration of 250 mg/L. The optimum dosage of nZVI obtained by IS-RPB was 4.0 g/L as the NB could be completely removed within 10 min, which reduced 20% compared with nZVI obtained by stirred tank reactor (STR). The reduction of NB and production of aniline (AN) followed pseudo-first-order kinetics, and the pseudo-first-order rate constants were 0.0147 and 0.0034 s{sup −1}, respectively. Furthermore, the as-prepared nZVI using IS-RPB reactor in this work can be used within a relatively wide range pH of 1–9.

  1. Biodegradation of 4-bromophenol by Arthrobacter chlorophenolicus A6 in batch shake flasks and in a continuously operated packed bed reactor.

    Science.gov (United States)

    Sahoo, Naresh Kumar; Pakshirajan, Kannan; Ghosh, Pranab Kumar

    2014-04-01

    The present study investigated growth and biodegradation of 4-bromophenol (4-BP) by Arthrobacter chlorophenolicus A6 in batch shake flasks as well as in a continuously operated packed bed reactor (PBR). Batch growth kinetics of A. chlorophenolicus A6 in presence of 4-BP followed substrate inhibition kinetics with the estimated biokinetic parameters value of μ max = 0.246 h(-1), K i = 111 mg L(-1), K s  = 30.77 mg L(-1) and K = 100 mg L(-1). In addition, variations in the observed and theoretical biomass yield coefficient and maintenance energy of the culture were investigated at different initial 4-BP concentration. Results indicates that the toxicity tolerance and the biomass yield of A. chlorophenolicus A6 towards 4-BP was found to be poor as the organism utilized the substrate mainly for its metabolic maintenance energy. Further, 4-BP biodegradation performance by the microorganism was evaluated in a continuously operated PBR by varying the influent concentration and hydraulic retention time in the ranges 400-1,200 mg L(-1) and 24-7.5 h, respectively. Complete removal of 4-BP was achieved in the PBR up to a loading rate of 2,276 mg L(-1) day(-1).

  2. Electrodeposition of copper from a copper sulfate solution using a packed-bed continuous-recirculation flow reactor at high applied electric current

    Directory of Open Access Journals (Sweden)

    Meshaal F. Alebrahim

    2015-09-01

    Full Text Available The purpose of this study is mainly to investigate the performance of a packed-bed continuous-recirculation flow reactor at high applied electric current in removing copper, Cu(II, from simulated electrolyte by electrodeposition. The effects of pHo, circulation rate of flow, initial copper concentration, intensity of the applied current and the method of application of electric current, as to have a constant value during all the time of electrolysis or to be decreased with time, on copper electrodeposition and current efficiency are revealed. The results showed that the increase in pH (provided not lead to the deposition of Cu(OH2, initial concentration of the copper and flow rate increased the electrodeposition of copper as well as improved current efficiency. However, increasing intensity of the applied electric current led to an increase in the electrodeposition of copper and decreased electrical efficiency. It was also observed that reducing the intensity of applied electric current with time during the electrolysis process while maintaining other operating variables constant led to a significant reduction in the consumption of electrical energy used in the process of copper removal by electrodeposition; a reduction of 41.6% could be achieved.

  3. Continuous preparation of Fe{sub 3}O{sub 4} nanoparticles through Impinging Stream-Rotating Packed Bed reactor and their electrochemistry detection toward heavy metal ions

    Energy Technology Data Exchange (ETDEWEB)

    Fan, Hong-Lei [Shanxi Province Key Laboratory of Higee-Oriented Chemical Engineering, North University of China, Taiyuan, 030051 (China); Zhou, Shao-Feng [Shanxi Province Key Laboratory of Functional Nanocomposites, North University of China, Taiyuan, 030051 (China); Gao, Jing [Shanxi Province Key Laboratory of Higee-Oriented Chemical Engineering, North University of China, Taiyuan, 030051 (China); Liu, You-Zhi, E-mail: lyzzhongxin@126.com [Shanxi Province Key Laboratory of Higee-Oriented Chemical Engineering, North University of China, Taiyuan, 030051 (China)

    2016-06-25

    We reported the continuous preparation and electrochemical behavior toward heavy metal ions of the Fe{sub 3}O{sub 4} nanoparticles (Fe{sub 3}O{sub 4} NPs). This Fe{sub 3}O{sub 4} NPs were fabricated through a novel Impinging Stream-Rotating Packed Bed reactor with a high production rate of 2.23 kg/hour. The as-prepared Fe{sub 3}O{sub 4} NPs were quasi-spherical with a mean diameter of about 10 nm and shown the characteristics of superparamagnetism with the saturated magnetization of 60.5 emu/g. The electrochemical characterization of the as-prepared Fe{sub 3}O{sub 4} NPs toward heavy metal ions were evaluated using square wave anodic stripping voltammetry (SWASV) analysis. The results indicated that the modified electrode could be used to individual detection of Pb(II), Cu(II), Hg(II) and Cd(II). In particular, the modified electrode exhibited the selective detection toward Pb(II) with higher sensitivity of 14.9 μA/μM, while the response to Cu(II), Hg(II) and Cd(II) were negligible. Besides, the modified electrode shown good stability and potential practical applicability in the electrochemical determination of Pb(II). This above results offered a simple method for continuous preparation sensing materials in the application field of electrochemical detection of toxic metal ions through the technology of process intensification. - Highlights: • Fe{sub 3}O{sub 4} nanoparticles were continuous prepared through IS-RPB reactor. • The Fe{sub 3}O{sub 4} nanoparticles showed selective detection of heavy metal ions. • It exhibited favorable sensitivity (14.9 μA μM{sup −1}) and LOD (0.119 μM) for Pb(II). • The as-prepared nanoparticles showed favorable potential application.

  4. Continuous preparation of Fe3O4 nanoparticles through Impinging Stream-Rotating Packed Bed reactor and their electrochemistry detection toward heavy metal ions

    International Nuclear Information System (INIS)

    Fan, Hong-Lei; Zhou, Shao-Feng; Gao, Jing; Liu, You-Zhi

    2016-01-01

    We reported the continuous preparation and electrochemical behavior toward heavy metal ions of the Fe 3 O 4 nanoparticles (Fe 3 O 4 NPs). This Fe 3 O 4 NPs were fabricated through a novel Impinging Stream-Rotating Packed Bed reactor with a high production rate of 2.23 kg/hour. The as-prepared Fe 3 O 4 NPs were quasi-spherical with a mean diameter of about 10 nm and shown the characteristics of superparamagnetism with the saturated magnetization of 60.5 emu/g. The electrochemical characterization of the as-prepared Fe 3 O 4 NPs toward heavy metal ions were evaluated using square wave anodic stripping voltammetry (SWASV) analysis. The results indicated that the modified electrode could be used to individual detection of Pb(II), Cu(II), Hg(II) and Cd(II). In particular, the modified electrode exhibited the selective detection toward Pb(II) with higher sensitivity of 14.9 μA/μM, while the response to Cu(II), Hg(II) and Cd(II) were negligible. Besides, the modified electrode shown good stability and potential practical applicability in the electrochemical determination of Pb(II). This above results offered a simple method for continuous preparation sensing materials in the application field of electrochemical detection of toxic metal ions through the technology of process intensification. - Highlights: • Fe 3 O 4 nanoparticles were continuous prepared through IS-RPB reactor. • The Fe 3 O 4 nanoparticles showed selective detection of heavy metal ions. • It exhibited favorable sensitivity (14.9 μA μM −1 ) and LOD (0.119 μM) for Pb(II). • The as-prepared nanoparticles showed favorable potential application.

  5. Treatment of azo dye-containing wastewater by a Fenton-like process in a continuous packed-bed reactor filled with activated carbon

    Energy Technology Data Exchange (ETDEWEB)

    Mesquita, Isabel; Matos, Luis C. [Chemical Engineering Department, Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias, 4200-465 Porto (Portugal); Duarte, Filipa [Chemical Engineering Department, Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias, 4200-465 Porto (Portugal); LEPAE - Laboratory for Process, Environmental and Energy Engineering, Department of Chemical Engineering, Faculty of Engineering, University of Porto, Porto (Portugal); Maldonado-Hodar, F.J. [Department of Inorganic Chemistry, Faculty of Sciences, University of Granada, Av. Fuentenueva, 18071 Granada (Spain); Mendes, Adelio [Chemical Engineering Department, Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias, 4200-465 Porto (Portugal); LEPAE - Laboratory for Process, Environmental and Energy Engineering, Department of Chemical Engineering, Faculty of Engineering, University of Porto, Porto (Portugal); Madeira, Luis M., E-mail: mmadeira@fe.up.pt [Chemical Engineering Department, Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias, 4200-465 Porto (Portugal); LEPAE - Laboratory for Process, Environmental and Energy Engineering, Department of Chemical Engineering, Faculty of Engineering, University of Porto, Porto (Portugal)

    2012-10-30

    Highlights: Black-Right-Pointing-Pointer Oxidation with the Fenton's reagent was carried out in a packed-bed reactor. Black-Right-Pointing-Pointer The packed-bed was filled with iron-impregnated activated carbon. Black-Right-Pointing-Pointer The increment of temperature increases the Chicago Sky Blue removal and mineralization. Black-Right-Pointing-Pointer The values of iron leaching were below 0.4 ppm in the outlet effluent. Black-Right-Pointing-Pointer It was possible to reach a dye conversion of 88% in steady-state. - Abstract: In this work, oxidation with a Fenton-like process of a dye solution was carried out in a packed-bed reactor. Activated carbon Norit RX 3 Extra was impregnated with ferrous sulfate and used as catalyst (7 wt.% of iron). The effect of the main operating conditions in the Chicago Sky Blue (CSB) degradation was analyzed. It was found that the increase in temperature leads to a higher removal of the dye and an increased mineralization. However, it also increases the iron leaching, but the values observed were below 0.4 ppm (thus, far below European Union limits). It was possible to reach, at steady-state, a dye conversion of 88%, with a total organic carbon (TOC) removal of ca. 47%, being the reactor operated at 50 Degree-Sign C, pH 3, W{sub cat}/Q = 4.1 g min mL{sup -1} (W{sub cat} is the mass of catalyst and Q the total feed flow rate) and a H{sub 2}O{sub 2} feed concentration of 2.25 mM (for a CSB feed concentration of 0.012 mM). The same performance was reached in three consecutive cycles.

  6. Generation of continuous packed bed reactor with PVA-alginate blend immobilized Ochrobactrum sp. DGVK1 cells for effective removal of N,N-dimethylformamide from industrial effluents

    Energy Technology Data Exchange (ETDEWEB)

    Sanjeev Kumar, S.; Kumar, M. Santosh [Department of Biochemistry, Gulbarga University, Gulbarga 585106, Karnataka (India); Siddavattam, D. [Department of Animal Sciences, University of Hyderabad, Hyderabad 500046 (India); Karegoudar, T.B., E-mail: goudartbk@gmail.com [Department of Biochemistry, Gulbarga University, Gulbarga 585106, Karnataka (India)

    2012-01-15

    Highlights: Black-Right-Pointing-Pointer Removal of DMF was compared by free and immobilized cells of Ochrobactrum sp. DGVK1. Black-Right-Pointing-Pointer Ochrobactrum sp. DGVK1 cells entrapped in PVA-alginate have shown more tolerance. Black-Right-Pointing-Pointer PVA-alginate beads removed DMF even in the presence of other organic solvents. Black-Right-Pointing-Pointer Removal of DMF from industrial effluents by PVA-alginate blended batch operations. Black-Right-Pointing-Pointer Development of industrially feasible remediation strategy for DMF removal. - Abstract: Effective removal of dimethylformamide (DMF), the organic solvent found in industrial effluents of textile and pharma industries, was demonstrated by using free and immobilized cells of Ochrobactrum sp. DGVK1, a soil isolate capable of utilizing DMF as a sole source of carbon, nitrogen. The free cells have efficiently removed DMF from culture media and effluents, only when DMF concentration was less than 1% (v/v). Entrapment of cells either in alginate or in polyvinyl alcohol (PVA) failed to increase tolerance limits. However, the cells of Ochrobactrum sp. DGVK1 entrapped in PVA-alginate mixed matrix tolerated higher concentration of DMF (2.5%, v/v) and effectively removed DMF from industrial effluents. As determined through batch fermentation, these immobilized cells have retained viability and degradability for more than 20 cycles. A continuous packed bed reactor, generated by using PVA-alginate beads, efficiently removed DMF from industrial effluents, even in the presence of certain organic solvents frequently found in effluents along with DMF.

  7. Operation of Packed-Bed Reactors Studied in Microgravity

    Science.gov (United States)

    Motil, Brian J.; Balakotaiah, Vemuri

    2004-01-01

    The operation of a packed bed reactor (PBR) involves gas and liquid flowing simultaneously through a fixed-bed of solid particles. Depending on the application, the particles can be various shapes and sizes but are generally designed to force the two fluid phases through a tortuous route of narrow channels connecting the interstitial space. The PBR is the most common type of reactor in industry because it provides for intimate contact and high rates of transport between the phases needed to sustain chemical or biological reactions. The packing may also serve as either a catalyst or as a support for growing biological material. Furthermore, this type of reactor is relatively compact and requires minimal power to operate. This makes it an excellent candidate for unit operations in support of long-duration human space activities.

  8. Continuous Process for Biodiesel Production in Packed Bed Reactor from Waste Frying Oil Using Potassium Hydroxide Supported on Jatropha curcas Fruit Shell as Solid Catalyst

    Directory of Open Access Journals (Sweden)

    Achanai Buasri

    2012-08-01

    Full Text Available The transesterification of waste frying oil (WFO with methanol in the presence of potassium hydroxide catalyst supported on Jatropha curcas fruit shell activated carbon (KOH/JS was studied. The catalyst systems were characterized by X-ray diffraction (XRD, scanning electron microscopy (SEM and the Brunauer–Emmett–Teller (BET method. The effects of reaction variables such as residence time, reaction temperature, methanol/oil molar ratio and catalyst bed height in packed bed reactor (PBR on the yield of biodiesel were investigated. SEM images showed that KOH was well distributed on the catalyst support. The optimum conditions for achieving the conversion yield of 86.7% consisted of a residence time of 2 h, reaction temperature of 60 °C, methanol/oil molar ratio of 16 and catalyst bed height of 250 mm. KOH/JS could be used repeatedly five times without any activation treatment, and no significant activity loss was observed. The results confirmed that KOH/JS catalyst had a great potential to be used for industrial application in the transesterification of WFO. The fuel properties of biodiesel were also determined.

  9. Immobilised native plant cysteine proteases: packed-bed reactor for white wine protein stabilisation

    OpenAIRE

    Benucci, Ilaria; Lombardelli, Claudio; Liburdi, Katia; Acciaro, Giuseppe; Zappino, Matteo; Esti, Marco

    2015-01-01

    This research presents a feasibility study of using a continuous packed-bed reactor (PBR), containing immobilised native plant cysteine proteases, as a specific and mild alternative technique relative to the usual bentonite fining for white wine protein stabilisation. The operational parameters for a PBR containing immobilised bromelain (PBR-br) or immobilised papain (PBR-pa) were optimised using model wine fortified with synthetic substrate (Bz-Phe-Val-Arg-pNA). The effectiveness of PBR-br, ...

  10. Biological perchlorate reduction in packed bed reactors using elemental sulfur.

    Science.gov (United States)

    Sahu, Ashish K; Conneely, Teresa; Nüsslein, Klaus R; Ergas, Sarina J

    2009-06-15

    Sulfur-utilizing perchlorate (ClO4-)-reducing bacteria were enriched from a denitrifying wastewater seed with elemental sulfur (S0) as an electron donor. The enrichment was composed of a diverse microbial community, with the majority identified as members of the phylum Proteobacteria. Cultures were inoculated into bench-scale packed bed reactors (PBR) with S0 and crushed oyster shell packing media. High ClO4-concentrations (5-8 mg/L) were reduced to PBR performance decreased when effluent recirculation was applied or when smaller S0 particle sizes were used, indicating that mass transfer of ClO4- to the attached biofilm was not the limiting mechanism in this process, and that biofilm acclimation and growth were key factors in overall reactor performance. The presence of nitrate (6.5 mg N/L) inhibited ClO4- reduction. The microbial community composition was found to change with ClO4- availability from a majority of Beta-Proteobacteria near the influent end of the reactor to primarily sulfur-oxidizing bacteria near the effluent end of the reactor.

  11. Modeling a Packed Bed Reactor Utilizing the Sabatier Process

    Science.gov (United States)

    Shah, Malay G.; Meier, Anne J.; Hintze, Paul E.

    2017-01-01

    A numerical model is being developed using Python which characterizes the conversion and temperature profiles of a packed bed reactor (PBR) that utilizes the Sabatier process; the reaction produces methane and water from carbon dioxide and hydrogen. While the specific kinetics of the Sabatier reaction on the RuAl2O3 catalyst pellets are unknown, an empirical reaction rate equation1 is used for the overall reaction. As this reaction is highly exothermic, proper thermal control is of the utmost importance to ensure maximum conversion and to avoid reactor runaway. It is therefore necessary to determine what wall temperature profile will ensure safe and efficient operation of the reactor. This wall temperature will be maintained by active thermal controls on the outer surface of the reactor. Two cylindrical PBRs are currently being tested experimentally and will be used for validation of the Python model. They are similar in design except one of them is larger and incorporates a preheat loop by feeding the reactant gas through a pipe along the center of the catalyst bed. The further complexity of adding a preheat pipe to the model to mimic the larger reactor is yet to be implemented and validated; preliminary validation is done using the smaller PBR with no reactant preheating. When mapping experimental values of the wall temperature from the smaller PBR into the Python model, a good approximation of the total conversion and temperature profile has been achieved. A separate CFD model incorporates more complex three-dimensional effects by including the solid catalyst pellets within the domain. The goal is to improve the Python model to the point where the results of other reactor geometry can be reasonably predicted relatively quickly when compared to the much more computationally expensive CFD approach. Once a reactor size is narrowed down using the Python approach, CFD will be used to generate a more thorough prediction of the reactors performance.

  12. Packed bed reactor treatment of liquid hazardous and mixed wastes

    International Nuclear Information System (INIS)

    Tennant, R.A.; Wantuck, P.J.; Vargas, R.

    1992-01-01

    We are developing thermal-based packed bed reactor (PBR) technology as an alternative to incineration for treatment of hazardous organic liquid wastes. The waste streams targeted by this technology are machining fluids contaminated with chlorocarbons and/or chlorofluorocarbons and low levels of plutonium or tritium The PBR offers several distinct advantages including simplistic design, rugged construction, ambient pressure processing, economical operations, as well as ease of scalability and maintainability. In this paper, we provide a description of the apparatus as well as test results using prepared mixtures of machining oils/emulsions with trichloroethylene (TCE), carbon tetrachloride (CCl 4 ), trichloroethane (TCA), and Freon TF. The current treatment system is configured as a two stage device with the PBR (1st stage) coupled to a silent discharge plasma (SDP) cell. The SDP serves as a second stage for further treatment of the gaseous effluent from the PBR. One of the primary advantages of this two stage system is that its suitability for closed loop operation where radioactive components are well contained and even CO 2 is not released to the environment

  13. Properties Influencing Plasma Discharges in Packed Bed Reactors

    Science.gov (United States)

    Kruszelnicki, Juliusz; Engeling, Kenneth W.; Foster, John E.; Kushner, Mark J.

    2016-09-01

    Atmospheric pressure dielectric barrier discharges (DBDs) sustained in packed bed reactors (PBRs) are being investigated for CO2 removal and conversion of waste gases into higher value compounds. We report on results of a computational investigation of PBR-DBD properties using the plasma hydrodynamics simulator nonPDPSIM with a comparison to experiments. Dielectric beads (rods in 2D) were inserted between two coplanar electrodes, 1 cm apart filled by humid air. A step-pulse of -30 kV was applied to the top electrode. Material properties of the beads (dielectric constant, secondary emission coefficient) and gas properties (photoionization and photo-absorption cross-sections, temperature) were varied. We found that photoionization plays a critical role in the propagation of the discharge through the PBR, as it serves to seed charges in regions of high electric field. Increasing rates of photo-ionization enable increases in the discharge propagation velocity, ionization rates and production of radicals. A transition between DBD-like and arc-like discharges occurs as the radiation mean free path decreases. Increasing the dielectric constant of the beads increased electric fields in the gas, which translated to increased discharge propagation velocity and charge density until ɛ/ɛ0 100. Secondary electron emission coefficient and gas temperature have minimal impacts on the discharge propagation though the latter did affect the production of reactive species. Work supported by US DOE Office of Fusion Energy Science and the National Science Foundation.

  14. Experimental and modelling study of drinking water hydrogenotrophic denitrification in packed-bed reactors

    International Nuclear Information System (INIS)

    Vasiliadou, I.A.; Karanasios, K.A.; Pavlou, S.; Vayenas, D.V.

    2009-01-01

    The aim of this work was to study hydrogenotrophic denitrification in packed-bed reactors under draw-fill and continuous operation. Three bench-scale packed-bed reactors with gravel in different sizes (mean diameter 1.75, 2.41 and 4.03 mm) as support media were used, in order to study the effect of particle size on reactors performance. The maximum denitrification rate achieved under draw-fill operation was 4.4 g NO 3 - -N/ld for the filter with gravel of 2.41 mm. This gravel size was chosen to perform experiments under continuous operation. Feed NO 3 - -N concentrations and hydraulic loadings (HL) ranged between 20-200 mg/l and 5.7-22.8 m 3 /m 2 d, respectively. A comparison between the two operating modes showed that, for low HL the draw-fill operation achieved higher denitrification rates, while for high HL and intermediate feed concentrations (40-60 mg NO 3 - -N/l) the continuous operation achieved higher denitrification rates (4.67-5.65 g/ld). Finally, experiments with three filters in series (with gravels of 4.03, 2.41 and 1.75 mm mean diameter) were also performed under continuous operation. The maximum denitrification rate achieved was 6.2 g NO 3 - -N/ld for feed concentration of 340 mg/l and HL of 11.5 m 3 /m 2 d. A model, which describes denitrification in packed-bed reactors, was also developed. The model predicts the concentration profiles of NO 3 - -N along filter height, in draw-fill as well as in continuous operation, satisfactorily.

  15. Aerobic biodegradation of a sulfonated phenylazonaphthol dye by a bacterial community immobilized in a multistage packed-bed BAC reactor.

    Science.gov (United States)

    Ruiz-Arias, Alfredo; Juárez-Ramírez, Cleotilde; de los Cobos-Vasconcelos, Daniel; Ruiz-Ordaz, Nora; Salmerón-Alcocer, Angélica; Ahuatzi-Chacón, Deifilia; Galíndez-Mayer, Juvencio

    2010-11-01

    A microbial community able to aerobically degrade the azo dye Acid Orange 7 was selected from riparian or lacustrine sediments collected at sites receiving textile wastewaters. Three bacterial strains, pertaining to the genera Pseudomonas, Arthrobacter, and Rhizobium, constitute the selected community. The biodegradation of AO7 was carried out in batch-suspended cell culture and in a continuously operated multistage packed-bed BAC reactor. The rapid decolorization observed in batch culture, joined to a delay of about 24 h in COD removal and cell growth, suggests that enzymes involved in biodegradation of the aromatic amines generated after AO7 azo-bond cleavage (1-amino-2-naphthol [1-A2N] and 4-aminobenzenesulfonic acid [4-ABS]), are inducible in this microbial consortium. After this presumptive induction period, the accumulated byproducts, measured through COD, were partially metabolized and transformed in cell mass. At all azo dye loading rates used, complete removal of AO7 and 1-A2N was obtained in the multistage packed-bed BAC reactor (PBR).; however, the overall COD (eta ( COD )) and 4-ABS (eta ( ABS )) removal efficiencies obtained in steady state continuous culture were about 90%. Considering the toxicity of 1-A2N, its complete removal has particular relevance. In the first stages of the packed-bed BAC reactor (Fig. 4a-c), major removal was observed. In the last stage, only a slight removal of COD and 4-ABS was obtained. Comparing to several reported studies, the continuously operated multistage packed-bed BAC reactor showed similar or superior results. In addition, the operation of large-packed-bed BAC reactors could be improved by using several shallow BAC bed stages, because the pressure drop caused by bed compaction of a support material constituted by small and fragile particles can be reduced.

  16. Effect of Mass-Transport Limitations on the Performance of a Packed Bed Membrane Reactor for Partial Oxidations. Transport from the Membrane to the Packed Bed

    NARCIS (Netherlands)

    van Sint Annaland, M.; Kurten, U.; Kuipers, J.A.M.

    2007-01-01

    With a packed bed membrane reactor, the product yield can be significantly enhanced for partial oxidation systems, via distributive addition of oxygen to the reaction mixture along the axial coordinate of the reactor, provided that the reaction order in oxygen of the formation rate of the target

  17. Effect of mass-transport limitations on the performance of a packed bed membrane reactor for partial oxidations. Transport from the membrane to the packed bed

    NARCIS (Netherlands)

    Sint Annaland, van M.; Kurten, U.; Kuipers, J.A.M.

    2007-01-01

    With a packed bed membrane reactor, the product yield can be significantly enhanced for partial oxidation systems, via distributive addition of oxygen to the reaction mixture along the axial coordinate of the reactor, provided that the reaction order in oxygen of the formation rate of the target

  18. Theoretical comparison of packed bed and fluidized bed membrane reactors for methane reforming

    NARCIS (Netherlands)

    Gallucci, F.; van Sint Annaland, M.; Kuipers, J.A.M.

    2010-01-01

    In this theoretical work the performance of different membrane reactor concepts, both fluidized bed and packed bed membrane reactors, has been compared for ultra-pure hydrogen production via methane reforming. Using detailed theoretical models, the required membrane area to reach a given conversion

  19. Comparison of packed bed and fluidized bed membrane reactors for methane reforming

    NARCIS (Netherlands)

    Gallucci, F.; van Sint Annaland, M.; Kuipers, J.A.M.

    2009-01-01

    In this work the performance of different membrane reactor concepts, both fluidized bed and packed bed membrane reactors, have been compared for the reforming of methane for the production of ultra-pure hydrogen. Using detailed theoretical models, the required membrane area to reach a given

  20. Model description and kinetic parameter analysis of MTBE biodegradation in a packed bed reactor

    DEFF Research Database (Denmark)

    Waul, Christopher Kevin; Arvin, Erik; Schmidt, Jens Ejbye

    2008-01-01

    A dynamic modeling approach was used to estimate in-situ model parameters, which describe the degradation of methyl tert-butyl ether (MTBE) in a laboratory packed bed reactor. The measured dynamic response of MTBE pulses injected at the reactor's inlet was analyzed by least squares and parameter...

  1. Discharge Characteristics of Series Surface/Packed-Bed Discharge Reactor Diven by Bipolar Pulsed Power

    International Nuclear Information System (INIS)

    Hu Jian; Jiang Nan; Li Jie; Shang Kefeng; Lu Na; Wu Yan; Mizuno Akira

    2016-01-01

    The discharge characteristics of the series surface/packed-bed discharge (SSPBD) reactor driven by bipolar pulse power were systemically investigated in this study. In order to evaluate the advantages of the SSPBD reactor, it was compared with traditional surface discharge (SD) reactor and packed-bed discharge (PBD) reactor in terms of the discharge voltage, discharge current, and ozone formation. The SSPBD reactor exhibited a faster rising time and lower tail voltage than the SD and PBD reactors. The distribution of the active species generated in different discharge regions of the SSPBD reactor was analyzed by optical emission spectra and ozone analysis. It was found that the packed-bed discharge region (3.5 mg/L), rather than the surface discharge region (1.3 mg/L) in the SSPBD reactor played a more important role in ozone generation. The optical emission spectroscopy analysis indicated that more intense peaks of the active species (e.g. N2 and OI) in the optical emission spectra were observed in the packed-bed region. (paper)

  2. Discharge Characteristics of Series Surface/Packed-Bed Discharge Reactor Diven by Bipolar Pulsed Power

    Science.gov (United States)

    Hu, Jian; Jiang, Nan; Li, Jie; Shang, Kefeng; Lu, Na; Wu, Yan; Mizuno, Akira

    2016-03-01

    The discharge characteristics of the series surface/packed-bed discharge (SSPBD) reactor driven by bipolar pulse power were systemically investigated in this study. In order to evaluate the advantages of the SSPBD reactor, it was compared with traditional surface discharge (SD) reactor and packed-bed discharge (PBD) reactor in terms of the discharge voltage, discharge current, and ozone formation. The SSPBD reactor exhibited a faster rising time and lower tail voltage than the SD and PBD reactors. The distribution of the active species generated in different discharge regions of the SSPBD reactor was analyzed by optical emission spectra and ozone analysis. It was found that the packed-bed discharge region (3.5 mg/L), rather than the surface discharge region (1.3 mg/L) in the SSPBD reactor played a more important role in ozone generation. The optical emission spectroscopy analysis indicated that more intense peaks of the active species (e.g. N2 and OI) in the optical emission spectra were observed in the packed-bed region. supported by National Natural Science Foundation of China (No. 51177007), the Joint Funds of National Natural Science Foundation of China (No. U1462105), and Dalian University of Technology Fundamental Research Fund of China (No. DUT15RC(3)030)

  3. Cost analysis of enzymatic biodiesel production in small-scaled packed-bed reactors

    NARCIS (Netherlands)

    Budzaki, S.; Miljic, G.; Sundaram, S.; Tisma, M.; Hessel, V.

    2017-01-01

    A cost analysis of enzymatic biodiesel production in small-scaled packed-bed reactors using refined sunflower oil is performed in this work. A few enzymatic micro-flow reactors have so far reached a performance close to gram-scale, which might be sufficient for the pharmaceutical industry. This

  4. Galacto-oligosaccharide production with immobilized ß-galactosidase in a packed-bed reactor vs. free ß-galactosidase in a batch reactor

    NARCIS (Netherlands)

    Warmerdam, A.; Benjamins, E.; Leeuw de, T.F.; Broekhuis, T.A.; Boom, R.M.; Janssen, A.E.M.

    2014-01-01

    We report here that the usage of immobilized enzyme in a continuous packed bed reactor (PBR) can be a good alternative for GOS production instead of the traditional use of free enzyme in a batch reactor. The carbohydrate composition of the product of the PBR with immobilized enzyme was comparable to

  5. Synthesis of Biodiesel in Batch and Packed-Bed Reactors Using Powdered and Granular Sugar Catalyst

    Science.gov (United States)

    Janaun, J.; Lim, P. M.; Balan, W. S.; Yaser, A. Z.; Chong, K. P.

    2017-06-01

    Increasing world production of palm oil warrants effective utilization of its waste. In particular, conversion of waste cooking oil into biodiesel has obtained global interest because of renewable energy need and reduction of CO2 emission. In this study, oleic acid used as a model compound for waste cooking oil conversion using esterification reaction catalysed by sugar catalyst (SC) in powdered (P-SC) and granular (G-SC) forms. The catalysts were synthesized via incomplete carbonization of D-glucose followed by functionalization with concentrated sulphuric acid. Catalysts characterizations were done for their physical and chemical properties using modern tools. Batch and packed-bed reactor systems were used to evaluate the reactivity of the catalysts. The results showed that G-SC had slightly higher total acidity and more porous than P-SC. The experimental conditions for batch reaction were temperature of 60°C, molar ratio of 1:20 (Oleic Acid:Methanol) and 2 wt. catalyst with respect to oleic acid. The results showed the maximum oleic acid conversion using G-SC and P-SC were 52 and 48, respectively. Whereas, the continuous reaction with varying feed flow rate as a function of retention time was studied by using 3 g of P-SC in 60 °C and 1:20 molar ratio in a packed-bed reactor. The results showed that a longer retention time which was 6.48 min and feed flow rate 1.38 ml/min, achieved higher average conversion of 9.9 and decreased with further increasing flow rate. G-SC showed a better average conversion of 10.8 at lowest feed flow rate of 1.38 ml/min in continuous reaction experiments. In a broader perspective, large scale continuous biodiesel production is feasible using granular over powdered catalyst mainly due to it lower pressure drop.

  6. Oxidation of ethene in a wall-cooled packed-bed reactor

    NARCIS (Netherlands)

    Schouten, E.P.S.; Borman, P.C.; Westerterp, K.R.

    1994-01-01

    The selective oxidation of ethene over a silver on α-alumina catalyst was studied in a pilot plant with a wall-cooled tubular packed bed reactor. Gas and solid temperatures in the catalyst bed were measured at different axial and radial positions as well as concentrations at different axial

  7. Production of structured lipids in a packed-bed reactor with Thermomyces lanuginosa lipase

    DEFF Research Database (Denmark)

    Xu, Xuebing; Porsgaard, Trine; Zhang, Hong

    2002-01-01

    Lipase-catalyzed interesterification between fish oil and medium-chain TAG has been investigated in a packed-bed reactor with a commercially immobilized enzyme. The enzyme, a Thermomyces lanuginosa lipase immobilized on silica by granulation (Lipozyme TL IM; Novozymes A/S, Bagsvaerd, Denmark), ha...

  8. Experimental, kinetic and numerical modeling of hydrogen production by catalytic reforming of crude ethanol over a commercial catalyst in packed bed tubular reactor and packed bed membrane reactor

    International Nuclear Information System (INIS)

    Aboudheir, Ahmed; Akande, Abayomi; Idem, Raphael

    2006-01-01

    The demand for hydrogen energy has increased tremendously in recent years essentially because of the increase in the word energy consumption as well as recent developments in fuel cell technologies. The energy information administration has projected that world energy consumption will increase by 59% over the next two decades, from 1999 to 2020, in which the largest share is still dominated by fossil fuels (oil, natural gas and coal). Carbon dioxide (CO 2 ) emissions resulting from the combustion of these fossil fuels currently are estimated to account for three-fourth of human-caused CO 2 emissions worldwide. Greenhouse gas emission, including CO 2 , should be limited, as recommended at the Kyoto Conference, Japan, in December 1997. In this regard, hydrogen (H 2 ) has a significant future potential as an alternative fuel that can solve the problems of CO 2 emissions as well as the emissions of other air contaminants. One of the techniques to produce hydrogen is by reforming of hydrocarbons or biomass. Crude ethanol (a form of biomass, which essentially is fermentation broth) is easy to produce, is free of sulphur, has low toxicity, and is also safe to handle, transport and store. In addition, crude ethanol consists of oxygenated hydrocarbons, such as ethanol, lactic acid, glycerol, and maltose. These oxygenated hydrocarbons can be reformed completely to H 2 and CO 2 , the latter of which could be separated from H 2 by membrane technology. This provides for CO 2 capture for eventual storage or destruction. In the case of using crude ethanol, this will result in negative CO 2 , emissions. In this paper, we conducted experimental work on production of hydrogen by the catalytic reforming of crude ethanol over a commercial promoted Ni-based catalyst in a packed bed tubular reactor as well as a packed bed membrane reactor. As well, a rigorous numerical model was developed to simulate this process in both the catalytic packed bed tubular reactor and packed bed membrane

  9. Green synthesis of isopropyl myristate in novel single phase medium Part II: Packed bed reactor (PBR) studies.

    Science.gov (United States)

    Vadgama, Rajeshkumar N; Odaneth, Annamma A; Lali, Arvind M

    2015-12-01

    Isopropyl myristate is a useful functional molecule responding to the requirements of numerous fields of application in cosmetic, pharmaceutical and food industry. In the present work, lipase-catalyzed production of isopropyl myristate by esterification of myristic acid with isopropyl alcohol (molar ratio of 1:15) in the homogenous reaction medium was performed on a bench-scale packed bed reactors, in order to obtain suitable reaction performance data for upscaling. An immobilized lipase B from Candida antartica was used as the biocatalyst based on our previous study. The process intensification resulted in a clean and green synthesis process comprising a series of packed bed reactors of immobilized enzyme and water dehydrant. In addition, use of the single phase reaction system facilitates efficient recovery of the product with no effluent generated and recyclability of unreacted substrates. The single phase reaction system coupled with a continuous operating bioreactor ensures a stable operational life for the enzyme.

  10. Green synthesis of isopropyl myristate in novel single phase medium Part II: Packed bed reactor (PBR studies

    Directory of Open Access Journals (Sweden)

    Rajeshkumar N. Vadgama

    2015-12-01

    Full Text Available Isopropyl myristate is a useful functional molecule responding to the requirements of numerous fields of application in cosmetic, pharmaceutical and food industry. In the present work, lipase-catalyzed production of isopropyl myristate by esterification of myristic acid with isopropyl alcohol (molar ratio of 1:15 in the homogenous reaction medium was performed on a bench-scale packed bed reactors, in order to obtain suitable reaction performance data for upscaling. An immobilized lipase B from Candida antartica was used as the biocatalyst based on our previous study. The process intensification resulted in a clean and green synthesis process comprising a series of packed bed reactors of immobilized enzyme and water dehydrant. In addition, use of the single phase reaction system facilitates efficient recovery of the product with no effluent generated and recyclability of unreacted substrates. The single phase reaction system coupled with a continuous operating bioreactor ensures a stable operational life for the enzyme.

  11. Process integration for biological sulfate reduction in a carbon monoxide fed packed bed reactor.

    Science.gov (United States)

    Kumar, Manoj; Sinharoy, Arindam; Pakshirajan, Kannan

    2018-05-09

    This study examined immobilized anaerobic biomass for sulfate reduction using carbon monoxide (CO) as the sole carbon source under batch and continuous fed conditions. The immobilized bacteria with beads made of 10% polyvinyl alcohol (PVA) showed best results in terms of sulfate reduction (84 ± 3.52%) and CO utilization (98 ± 1.67%). The effect of hydraulic retention time (HRT), sulfate loading rate and CO loading rate on sulfate and CO removal was investigated employing a 1L packed bed bioreactor containing the immobilized biomass. At 48, 24 and 12 h HRT, the sulfate removal was 94.42 ± 0.15%, 89.75 ± 0.47% and 61.08 ± 0.34%, respectively, along with a CO utilization of more than 90%. The analysis of variance (ANOVA) of the results obtained showed that only the initial CO concentration significantly affected the sulfate reduction process. The reactor effluent sulfate concentrations were 27.41 ± 0.44, 59.16 ± 1.08, 315.83 ± 7.33 mg/L for 250, 500 and 1000 mg/L of influent sulfate concentrations respectively, under the optimum operating conditions. The sulfate reduction rates matched well with low inlet sulfate loading rates, indicating stable performance of the bioreactor system. Overall, this study yielded very high sulfate reduction efficiency by the immobilized anaerobic biomass under high CO loading condition using the packed bed reactor system. Copyright © 2018 Elsevier Ltd. All rights reserved.

  12. A bibliographic review of mathematical models of packed-bed biological reactors (PBR

    Directory of Open Access Journals (Sweden)

    Deisy Corredor

    2005-09-01

    Full Text Available Several authors have sublected packed-bed biological reactors to mathematical and theoretical analysis. They have taken reaction kinetics and single-dimensional, homogeneous, pseudo-homogeneous and heterogeneous models into account. Numerical methods have provided the set of equations so developed. The effect of physically important process variables in terms of design and operation have been investigated (i.e. residence time, operating- flow, substrate conversion, bio-film area and film thickness.

  13. Breakthrough of toluene vapours in granular activated carbon filled packed bed reactor

    International Nuclear Information System (INIS)

    Mohan, N.; Kannan, G.K.; Upendra, S.; Subha, R.; Kumar, N.S.

    2009-01-01

    The objective of this research was to determine the toluene removal efficiency and breakthrough time using commercially available coconut shell-based granular activated carbon in packed bed reactor. To study the effect of toluene removal and break point time of the granular activated carbon (GAC), the parameters studied were bed lengths (2, 3, and 4 cm), concentrations (5, 10, and 15 mg l -1 ) and flow rates (20, 40, and 60 ml/min). The maximum percentage removal of 90% was achieved and the maximum carbon capacity for 5 mg l -1 of toluene, 60 ml/min flow rate and 3 cm bed length shows 607.14 mg/g. The results of dynamic adsorption in a packed bed were consistent with those of equilibrium adsorption by gravimetric method. The breakthrough time and quantity shows that GAC with appropriate surface area can be utilized for air cleaning filters. The result shows that the physisorption plays main role in toluene removal.

  14. Immobilised native plant cysteine proteases: packed-bed reactor for white wine protein stabilisation.

    Science.gov (United States)

    Benucci, Ilaria; Lombardelli, Claudio; Liburdi, Katia; Acciaro, Giuseppe; Zappino, Matteo; Esti, Marco

    2016-02-01

    This research presents a feasibility study of using a continuous packed-bed reactor (PBR), containing immobilised native plant cysteine proteases, as a specific and mild alternative technique relative to the usual bentonite fining for white wine protein stabilisation. The operational parameters for a PBR containing immobilised bromelain (PBR-br) or immobilised papain (PBR-pa) were optimised using model wine fortified with synthetic substrate (Bz-Phe-Val-Arg-pNA). The effectiveness of PBR-br, both in terms of hazing potential and total protein decrease, was significantly higher than PBR-pa, in all the seven unfined, white wines used. Among the wines tested, Sauvignon Blanc, given its total protein content as well as its very high intrinsic instability, was selected as a control wine to evaluate the effect of the treatment on wine as to its soluble protein profile, phenolic composition, mineral component, and sensory properties. The treatment in a PBR containing immobilised bromelain appeared effective in decreasing both wine hazing potential and total protein amount, while it did not significantly affect the phenol compounds, the mineral component nor the sensory quality of wine. The enzymatic treatment in PBR was shown to be a specific and mild technique for use as an alternative to bentonite fining for white wine protein stabilisation.

  15. Kinetics of pyridine degradation along with toluene and methylene chloride with Bacillus sp. in packed bed reactor

    Energy Technology Data Exchange (ETDEWEB)

    Uma, B.; Sandhya, S. [National Environmental Engineering Research Institute, CSIR-Complex, Madras (India)

    1998-04-01

    Bacillus coagulans strain isolated from contaminated soil was immobilised on activated carbon for degradation of pyridine, toluene and methylene chloride containing synthetic wastewaters. Pyridine was supplied as the only source of nitrogen in the wastewaters. Continuous runs in a packed bed laboratory reactor showed that immobilized B. coagulans can degrade pyridine along with other organics rapidly and the effluent ammonia is also controlled in presence of ``organic carbon``. About 644 mg/l of influent TOC was efficiently degraded (82.85%) at 64.05 mg/l/hr loading. (orig.) With 2 figs., 4 tabs., 15 refs.

  16. Syngas fermentation by Clostridium carboxidivorans P7 in a horizontal rotating packed bed biofilm reactor with enhanced ethanol production

    International Nuclear Information System (INIS)

    Shen, Yanwen; Brown, Robert C.; Wen, Zhiyou

    2017-01-01

    Highlights: • A novel a horizontal rotating packed bed (h-RPB) reactor for syngas fermentation was reported. • The h-RPB reactor enhanced ethanol productivity by 3.3-folds compared to continuous stirred tank reactor (CSTR). • The h-RPB reactor has a unique feature of transfer gas from both bulk liquid phase and headspace phase. • The mass transfer in the headspace of h-PRB played an important role for enhanced ethanol production. - Abstract: Gasification of lignocellulosic biomass followed by syngas fermentation is a promising process for producing fuels and chemicals. Syngas fermentation, however, is commonly limited by low mass transfer rates. In this work, a horizontally oriented rotating packed bed (h-RPB) reactor was developed to improve mass transfer and enhance ethanol production. In the h-RPB reactor, cell attachment materials were packed in the reactor and half submerged in the liquid and half exposed to the headspace. With continuous rotation of the packing materials, the cells in biofilm were alternately in contact with liquid and headspace; thus, transport of syngas to the cells occurred in both the liquid phase and headspace. The volumetric mass transfer coefficient (k_La) of the h-RPB reactor was lower than that in a traditional continuous stirred tank reactor (CSTR), indicating the mass transfer in the liquid phase of h-PRB was lower than CSTR, and the mass transfer in the headspace phase played an important role in syngas fermentation. The syngas fermentation of Clostridium carboxidivorans P7 in h-RPB resulted in a 7.0 g/L titer and 6.7 g/L/day productivity of ethanol, respectively, 3.3 times higher than those obtained in a CSTR under the same operational conditions. The results demonstrate that the h-RPB reactor is an efficient system for syngas fermentation, making cellulosic ethanol biorefinery one step closer to technical and economic feasibility.

  17. Packed bed reactor for degradation of simulated cyanide-containing wastewater

    OpenAIRE

    Kumar, Virender; Kumar, Vijay; Bhalla, Tek Chand

    2014-01-01

    The discharge of cyanide-containing effluents into the environment contaminates water bodies and soil. Effective methods of treatment which can detoxify cyanide are the need of the hour. The aim of the present study is to develop a bioreactor for complete degradation of cyanide using immobilized cells of Serratia marcescens RL2b. Alginate-entrapped cells of S. marcescens RL2b were used for complete degradation of cyanide in a packed bed reactor (PBR). Cells grown in minimal salt medium (pH 6....

  18. Chemical looping reforming in packed-bed reactors : modelling, experimental validation and large-scale reactor design

    NARCIS (Netherlands)

    Spallina, V.; Marinello, B.; Gallucci, F.; Romano, M.C.; van Sint Annaland, M.

    This paper addresses the experimental demonstration and model validation of chemical looping reforming in dynamically operated packed-bed reactors for the production of H2 or CH3OH with integrated CO2 capture. This process is a combination of auto-thermal and steam methane reforming and is carried

  19. Anaerobic Digestion of Sugarcane Vinasse Through a Methanogenic UASB Reactor Followed by a Packed Bed Reactor.

    Science.gov (United States)

    Cabrera-Díaz, A; Pereda-Reyes, I; Oliva-Merencio, D; Lebrero, R; Zaiat, M

    2017-12-01

    The anaerobic treatment of raw vinasse in a combined system consisting in two methanogenic reactors, up-flow anaerobic sludge blanket (UASB) + anaerobic packed bed reactors (APBR), was evaluated. The organic loading rate (OLR) was varied, and the best condition for the combined system was 12.5 kg COD m -3 day -1 with averages of 0.289 m 3 CH 4  kg COD r -1 for the UASB reactor and 4.4 kg COD m -3 day -1 with 0.207 m 3 CH 4  kg COD r -1 for APBR. The OLR played a major role in the emission of H 2 S conducting to relatively stable quality of biogas emitted from the APBR, with H 2 S concentrations <10 mg L -1 . The importance of the sulphate to COD ratio was demonstrated as a result of the low biogas quality recorded at the lowest ratio. It was possible to develop a proper anaerobic digestion of raw vinasse through the combined system with COD removal efficiency of 86.7% and higher CH 4 and a lower H 2 S content in biogas.

  20. Sequential UASB and dual media packed-bed reactors for domestic wastewater treatment - experiment and simulation.

    Science.gov (United States)

    Rodríguez-Gómez, Raúl; Renman, Gunno

    2016-01-01

    A wastewater treatment system composed of an upflow anaerobic sludge blanket (UASB) reactor followed by a packed-bed reactor (PBR) filled with Sorbulite(®) and Polonite(®) filter material was tested in a laboratory bench-scale experiment. The system was operated for 50 weeks and achieved very efficient total phosphorus (P) removal (99%), 7-day biochemical oxygen demand removal (99%) and pathogenic bacteria reduction (99%). However, total nitrogen was only moderately reduced in the system (40%). A model focusing on simulation of organic material, solids and size of granules was then implemented and validated for the UASB reactor. Good agreement between the simulated and measured results demonstrated the capacity of the model to predict the behaviour of solids and chemical oxygen demand, which is critical for successful P removal and recovery in the PBR.

  1. Phenols removal using ozonation-adsorption with granular activated carbon (GAC) in rotating packed bed reactor

    Science.gov (United States)

    Karamah, E. F.; Leonita, S.; Bismo, S.

    2018-01-01

    Synthetic wastewater containing phenols was treated using combination method of ozonation-adsorption with GAC (Granular Activated Carbon) in a packed bed rotating reactor. Ozone reacts quickly with phenol and activated carbon increases the oxidation process by producing hydroxyl radicals. Performance parameters evaluated are phenol removal percentage, the quantity of hydroxyl radical formed, changes in pH and ozone utilization, dissolved ozone concentration and ozone concentration in off gas. The performance of the combination method was compared with single ozonation and single adsorption. The influence of GAC dose and initial pH of phenols were evaluated in ozonation-adsorption method. The results show that ozonation-adsorption method generates more OH radicals than a single ozonation. Quantity of OH radical formation increases with increasing pH and quantity of the GAC. The combination method prove better performance in removing phenols. At the same operation condition, ozonation-adsorption method is capable of removing of 78.62% phenols as compared with single ozonation (53.15%) and single adsorption (36.67%). The increasing percentage of phenol removal in ozonation-adsorption method is proportional to the addition of GAC dose, solution pH, and packed bed rotator speed. Maximum percentage of phenol removal is obtained under alkaline conditions (pH 10) and 125 g of GAC

  2. Reactor design and operation strategies for a large-scale packed-bed CLC power plant with coal syngas

    NARCIS (Netherlands)

    Spallina, V.; Chiesa, P.; Martelli, E; Gallucci, F.; Romano, M.C.; Lozza, G.; Sint Annaland, van M.

    2015-01-01

    This paper deals with the design and operation strategies of dynamically operated packed-bed reactors (PBRs) of a chemical looping combustion (CLC) system included in an integrated gasification combined cycle (IGCC) for electric power generation with low CO2 emission from coal. The CLC reactors,

  3. Electrical Capacitance Volume Tomography for the Packed Bed Reactor ISS Flight Experiment

    Science.gov (United States)

    Marashdeh, Qussai; Motil, Brian; Wang, Aining; Liang-Shih, Fan

    2013-01-01

    Fixed packed bed reactors are compact, require minimum power and maintenance to operate, and are highly reliable. These features make this technology a highly desirable unit operation for long duration life support systems in space. NASA is developing an ISS experiment to address this technology with particular focus on water reclamation and air revitalization. Earlier research and development efforts funded by NASA have resulted in two hydrodynamic models which require validation with appropriate instrumentation in an extended microgravity environment. To validate these models, the instantaneous distribution of the gas and liquid phases must be measured.Electrical Capacitance Volume Tomography (ECVT) is a non-invasive imaging technology recently developed for multi-phase flow applications. It is based on distributing flexible capacitance plates on the peripheral of a flow column and collecting real-time measurements of inter-electrode capacitances. Capacitance measurements here are directly related to dielectric constant distribution, a physical property that is also related to material distribution in the imaging domain. Reconstruction algorithms are employed to map volume images of dielectric distribution in the imaging domain, which is in turn related to phase distribution. ECVT is suitable for imaging interacting materials of different dielectric constants, typical in multi-phase flow systems. ECVT is being used extensively for measuring flow variables in various gas-liquid and gas-solid flow systems. Recent application of ECVT include flows in risers and exit regions of circulating fluidized beds, gas-liquid and gas-solid bubble columns, trickle beds, and slurry bubble columns. ECVT is also used to validate flow models and CFD simulations. The technology is uniquely qualified for imaging phase concentrations in packed bed reactors for the ISS flight experiments as it exhibits favorable features of compact size, low profile sensors, high imaging speed, and

  4. Continuous D-tagatose production by immobilized thermostable L-arabinose isomerase in a packed-bed bioreactor.

    Science.gov (United States)

    Ryu, Se-Ah; Kim, Chang Sup; Kim, Hye-Jung; Baek, Dae Heoun; Oh, Deok-Kun

    2003-01-01

    D-Tagatose was continuously produced using thermostable L-arabinose isomerase immobilized in alginate with D-galactose solution in a packed-bed bioreactor. Bead size, L/D (length/diameter) of reactor, dilution rate, total loaded enzyme amount, and substrate concentration were found to be optimal at 0.8 mm, 520/7 mm, 0.375 h(-1), 5.65 units, and 300 g/L, respectively. Under these conditions, the bioreactor produced about 145 g/L tagatose with an average productivity of 54 g tagatose/L x h and an average conversion yield of 48% (w/w). Operational stability of the immobilized enzyme was demonstrated, with a tagatose production half-life of 24 days.

  5. Investigation of the Time Evolution and Species Production in a 2-Dimensional Packed Bed Reactor

    Science.gov (United States)

    Engeling, Kenneth; Kruszelnicki, Juliusz; Kushner, Mark; Foster, John

    2016-09-01

    Plasma production in microporous media has potential to enable a number of technologies ranging from flameless combustion to environmental hazard mitigation addressing air borne pollutants. Packed bed reactors (PBRs) is one such technology that relies on plasma production in microporous media. The physics of plasma production and transport in such media however remains poorly understood. In order to better understand the plasma propagation and plasma driven chemical reaction within microporous media, absorption spectroscopy and time-resolved imaging diagnostics are being utilized. We report on plasma driven species formation and plasma discharge spatial structure and evolution characteristics found in the 2-dimensional representation of a PBR. Work supported by US DOE Office of Fusion Energy Science and the National Science Foundation.

  6. Inulinase production in a packed bed reactor by solid state fermentation.

    Science.gov (United States)

    Dilipkumar, M; Rajamohan, N; Rajasimman, M

    2013-07-01

    In this work, production of inulinase was carried out in a packed bed reactor (PBR) under solid state fermentation. Kluyveromyces marxianus var. marxianus was used to produce the inulinase using pressmud as substrate. The parameters like air flow rate, packing density and particle size were optimized using response surface methodology (RSM) to maximize the inulinase production. The optimum conditions for the maximum inulinase production were: air flow rate - 0.82 L/min, packing density - 40 g/L and particle size - 0.0044 mm (mesh - 14/20). At these optimized conditions, the production of inulinase was found to be 300.5 unit/gram of dry substrate (U/gds). Copyright © 2013 Elsevier Ltd. All rights reserved.

  7. Modeling the competitive effect of ammonium oxidizers and heterotrophs on the degradation of MTBE in a packed bed reactor

    DEFF Research Database (Denmark)

    Waul, Christopher Kevin; Arvin, Erik; Schmidt, Jens Ejbye

    2008-01-01

    A mathematical model was used to study effects on the degradation of methyl tert-butyl ether (MTBE) in a packed bed reactor due to the presence of contaminants such as ammonium, and the mix of benzene, toluene, ethylbenzene and xylenes (BTEX). It was shown that competition between the slower...

  8. Transformation of carbon tetrachloride in an anaerobic packed-bed reactor without addition of another electron donor

    NARCIS (Netherlands)

    de Best, JH; Hunneman, P; Doddema, HJ; Janssen, DB; Harder, W; Doddema, Hans J.

    1999-01-01

    Carbon tetrachloride (52 mu M) was biodegraded for more than 72% in an anaerobic packed-bed reactor without addition of an external electron donor. The chloride mass balance demonstrated that all carbon tetrachloride transformed was completely dechlorinated. Chloroform and dichloromethane were

  9. Transformation of carbon tetrachloride in an anaerobic packed-bed reactor without addition of another electron donor

    NARCIS (Netherlands)

    Best, J.H. de; Hunneman, P.; Doddema, H.J.; Janssen, D.B.; Harder, W.

    1999-01-01

    Carbon tetrachloride (52 μM) was biodegraded for more than 72% in an anaerobic packed-bed reactor without addition of an external electron donor. The chloride mass balance demonstrated that all carbon tetrachloride transformed was completely dechlorinated. Chloroform and dichloromethane were

  10. High throughput photo-oxidations in a packed bed reactor system.

    Science.gov (United States)

    Kong, Caleb J; Fisher, Daniel; Desai, Bimbisar K; Yang, Yuan; Ahmad, Saeed; Belecki, Katherine; Gupton, B Frank

    2017-12-01

    The efficiency gains produced by continuous-flow systems in conducting photochemical transformations have been extensively demonstrated. Recently, these systems have been used in developing safe and efficient methods for photo-oxidations using singlet oxygen generated by photosensitizers. Much of the previous work has focused on the use of homogeneous photocatalysts. The development of a unique, packed-bed photoreactor system using immobilized rose bengal expands these capabilities as this robust photocatalyst allows access to and elaboration from these highly useful building blocks without the need for further purification. With this platform we were able to demonstrate a wide scope of singlet oxygen ene, [4+2] cycloadditions and heteroatom oxidations. Furthermore, we applied this method as a strategic element in the synthesis of the high-volume antimalarial artemisinin. Copyright © 2017. Published by Elsevier Ltd.

  11. Ethanol production by immobilized yeast and its CO2 gas effects on a packed bed reactor

    Energy Technology Data Exchange (ETDEWEB)

    Cho, G M; Choi, C Y; Choi, Y D; Han, M H

    1982-10-01

    Immobilised yeast trapped in an alginate matrix demonstrated maximum activity at 30 degrees C and showed no pH effect between 3 and 7. Substrate inhibition was observed at glucose concentrations above 8% but the immobilised cells retained 70% of their maximum activity at 20% glucose concentration. The operation stability of immobilised cells was lower in simple glucose solution than in the activation medium in which only 20% of the activity was lost after 10 days operation. Inactivated immobilised yeast beads were reactivated by incubation in activation medium without a significant increase in cell numbers in a bead. During the operation of the immobilised yeast in a packed bed reactor, CO/sub 2/ gas accumulation adversely affected the reactor performance. An ideal plus flow reactor, not taking into account the formation of CO/sub 2/ gas bubbles and the presence of mass trasnfer resistance, was simulated using a kinetic model for the production of ethanol and the simulation results were compared with the actual reactor performance to determine the CO/sub 2/ gas effect, quantitatively. Up to 45% of the substrate conversion was lost due to the accumulation of CO/sub 2/ gas bubbles in all cases. (Refs. 21).

  12. Modeling and simulation of a packed bed reactor for hydrogen by methanol steam reforming

    International Nuclear Information System (INIS)

    Aboudheir, A.; Idem, R.

    2004-01-01

    'Full text:' The performance of a catalytic packed bed tubular reactor for hydrogen production depends on mass transport characteristics and temperature distribution in the reactor. To accurately predict this performance, a rigorous numerical model has been developed based on coupled mass, energy, and momentum balance equations in cylindrical coordinates. This comprehensive model takes into account the variations of the concentration and temperature in both the axial and radial directions as well as the pressure drop along the packed reactor. Also, experimental measurements for hydrogen production were collected using a manganese-promoted co-precipitated Cu-Al catalyst for methanol-steam reforming in a micro-reactor having 10 mm i.d. and 460 mm overall length. The operating temperature ranged from 443 to 523 K and the space-time ranged from 0.1 to 2.5 kg cat h/kmol CH3OH. The simulation results were found to be in close agreement with the experimental data over the various operating conditions. This confirms the validity of both the numerical model of this work and our previous published kinetics models for this reaction system. In addition, the model formulation is applicable to handle reactions, not only for the microreactor presented in this work, but also, for other laboratory size and industrial scale processes for hydrogen production by hydrocarbon reformation. (author)

  13. Simultaneous Coproduction of Hydrogen and Ethanol in Anaerobic Packed-Bed Reactors

    Directory of Open Access Journals (Sweden)

    Cristiane Marques dos Reis

    2014-01-01

    Full Text Available This study evaluated the use of an anaerobic packed-bed reactor for hydrogen production at different hydraulic retention times (HRT (1–8 h. Two reactors filled with expanded clay and fed with glucose (3136–3875 mg L−1 were operated at different total upflow velocities: 0.30 cm s−1 (R030 and 0.60 cm s−1 (R060. The effluent pH of the reactors was maintained between 4 and 5 by adding NaHCO3 and HCl solutions. It was observed a maximum hydrogen production rate of 0.92 L H2 h−1 L−1 in R030 at HRT of 1 h. Furthermore, the highest hydrogen yield of 2.39 mol H2 mol−1 glucose was obtained in R060. No clear trend was observed by doubling the upflow velocities at this experiment. High ethanol production was also observed, indicating that the ethanol-pathway prevailed throughout the experiment.

  14. Improved performance of parallel surface/packed-bed discharge reactor for indoor VOCs decomposition: optimization of the reactor structure

    International Nuclear Information System (INIS)

    Jiang, Nan; Hui, Chun-Xue; Li, Jie; Lu, Na; Shang, Ke-Feng; Wu, Yan; Mizuno, Akira

    2015-01-01

    The purpose of this paper is to develop a high-efficiency air-cleaning system for volatile organic compounds (VOCs) existing in the workshop of a chemical factory. A novel parallel surface/packed-bed discharge (PSPBD) reactor, which utilized a combination of surface discharge (SD) plasma with packed-bed discharge (PBD) plasma, was designed and employed for VOCs removal in a closed vessel. In order to optimize the structure of the PSPBD reactor, the discharge characteristic, benzene removal efficiency, and energy yield were compared for different discharge lengths, quartz tube diameters, shapes of external high-voltage electrode, packed-bed discharge gaps, and packing pellet sizes, respectively. In the circulation test, 52.8% of benzene was removed and the energy yield achieved 0.79 mg kJ −1 after a 210 min discharge treatment in the PSPBD reactor, which was 10.3% and 0.18 mg kJ −1 higher, respectively, than in the SD reactor, 21.8% and 0.34 mg kJ −1 higher, respectively, than in the PBD reactor at 53 J l −1 . The improved performance in benzene removal and energy yield can be attributed to the plasma chemistry effect of the sequential processing in the PSPBD reactor. The VOCs mineralization and organic intermediates generated during discharge treatment were followed by CO x selectivity and FT-IR analyses. The experimental results indicate that the PSPBD plasma process is an effective and energy-efficient approach for VOCs removal in an indoor environment. (paper)

  15. Treatment of chemical-pharmaceutical wastewater in packed bed anaerobic reactors

    Energy Technology Data Exchange (ETDEWEB)

    Nacheva, P.M.; Pena-Loera, B.; Moralez-Guzman, F. [Mexican Institute for Water Technology, Jiutepec (Mexico)

    2006-07-01

    Biological degradation in packed bed anaerobic mesophilic reactors with five different support materials was studied for the treatment of chemical-pharmaceutical wastewater with high COD (23-31 g/L), which contains toxic organic compounds. Experimental up-flow bio-filters were operated at different organic loads for a two-year period. Removals of 80-98% were obtained in the reactors with sand, anthracite and black tezontle, but at relatively low organic loads, less than 3.6 kg m{sup -3} d{sup -1}. The reactor with granular activated carbon (GAC) had a better performance; efficiencies higher than 95% were obtained at loads up to 17kg m{sup -3} d{sup -1} and higher than 80% with loads up to 26 kg m{sup -3} d{sup -1}. Second in performance was the reactor with red tezontle which allows COD removals higher than 80% with loads up to 6 kg m{sup -3} d{sup -1}. The use of GAC as support material allows greater biodegradation rates than the rest of the materials and it makes the process more resistant to organic load increases, inhibition effects and toxicity. Methanogenic activity was inhibited at loads higher than 21.9 kg m{sup -3} d{sup -1} in the GAC-reactor and at loads higher than 3.6 kg m{sup -3} d{sup -1} in the rest of the reactors. At loads lower than the previously mentioned, high methane production yield was obtained, 0.32-0.35 m{sup 33}CH4/kg CODremoved.

  16. Propagation of negative electrical discharges through 2-dimensional packed bed reactors

    International Nuclear Information System (INIS)

    Kruszelnicki, Juliusz; Engeling, Kenneth W; Foster, John E; Xiong, Zhongmin; Kushner, Mark J

    2017-01-01

    Plasma-based pollutant remediation and value-added gas production have recently gained increased attention as possible alternatives to the currently-deployed chemical reactor systems. Electrical discharges in packed bed reactors (PBRs) are of interest, due to their ability to synergistically combine catalytic and plasma chemical processes. In principle, these systems could be tuned to produce specific products, based on their application by combinations of power formats, materials, geometries and working gases. Negative voltage, atmospheric-pressure plasma discharges sustained in humid air in a PBR-like geometry were experimentally characterized using ICCD imaging and simulated in 2-dimensions (2D) to provide insights into possible routes to this tunability. Surface ionization waves (SIWs) and positive restrikes through the lattice of dielectric rods were shown to be the principal means of producing reactive species. The number and intensity of SIWs and restrikes are sensitive functions of the alignment of the lattice of dielectric beads (or rods in 2D) with respect to the applied electric field. Decreased spacing between the dielectric elements leads to an increased electric field enhancement in the gas, and therefore locally higher plasma densities, but does not necessarily impact the types of discharges that occur through the lattice. (paper)

  17. Evaluation of Heavy Metal Removal from Wastewater in a Modified Packed Bed Biofilm Reactor.

    Directory of Open Access Journals (Sweden)

    Shohreh Azizi

    Full Text Available For the effective application of a modified packed bed biofilm reactor (PBBR in wastewater industrial practice, it is essential to distinguish the tolerance of the system for heavy metals removal. The industrial contamination of wastewater from various sources (e.g. Zn, Cu, Cd and Ni was studied to assess the impacts on a PBBR. This biological system was examined by evaluating the tolerance of different strengths of composite heavy metals at the optimum hydraulic retention time (HRT of 2 hours. The heavy metal content of the wastewater outlet stream was then compared to the source material. Different biomass concentrations in the reactor were assessed. The results show that the system can efficiently treat 20 (mg/l concentrations of combined heavy metals at an optimum HRT condition (2 hours, while above this strength there should be a substantially negative impact on treatment efficiency. Average organic reduction, in terms of the chemical oxygen demand (COD of the system, is reduced above the tolerance limits for heavy metals as mentioned above. The PBBR biological system, in the presence of high surface area carrier media and a high microbial population to the tune of 10 000 (mg/l, is capable of removing the industrial contamination in wastewater.

  18. Evaluation of Heavy Metal Removal from Wastewater in a Modified Packed Bed Biofilm Reactor

    Science.gov (United States)

    Azizi, Shohreh; Kamika, Ilunga; Tekere, Memory

    2016-01-01

    For the effective application of a modified packed bed biofilm reactor (PBBR) in wastewater industrial practice, it is essential to distinguish the tolerance of the system for heavy metals removal. The industrial contamination of wastewater from various sources (e.g. Zn, Cu, Cd and Ni) was studied to assess the impacts on a PBBR. This biological system was examined by evaluating the tolerance of different strengths of composite heavy metals at the optimum hydraulic retention time (HRT) of 2 hours. The heavy metal content of the wastewater outlet stream was then compared to the source material. Different biomass concentrations in the reactor were assessed. The results show that the system can efficiently treat 20 (mg/l) concentrations of combined heavy metals at an optimum HRT condition (2 hours), while above this strength there should be a substantially negative impact on treatment efficiency. Average organic reduction, in terms of the chemical oxygen demand (COD) of the system, is reduced above the tolerance limits for heavy metals as mentioned above. The PBBR biological system, in the presence of high surface area carrier media and a high microbial population to the tune of 10 000 (mg/l), is capable of removing the industrial contamination in wastewater. PMID:27186636

  19. Propagation of negative electrical discharges through 2-dimensional packed bed reactors

    Science.gov (United States)

    Kruszelnicki, Juliusz; Engeling, Kenneth W.; Foster, John E.; Xiong, Zhongmin; Kushner, Mark J.

    2017-01-01

    Plasma-based pollutant remediation and value-added gas production have recently gained increased attention as possible alternatives to the currently-deployed chemical reactor systems. Electrical discharges in packed bed reactors (PBRs) are of interest, due to their ability to synergistically combine catalytic and plasma chemical processes. In principle, these systems could be tuned to produce specific products, based on their application by combinations of power formats, materials, geometries and working gases. Negative voltage, atmospheric-pressure plasma discharges sustained in humid air in a PBR-like geometry were experimentally characterized using ICCD imaging and simulated in 2-dimensions (2D) to provide insights into possible routes to this tunability. Surface ionization waves (SIWs) and positive restrikes through the lattice of dielectric rods were shown to be the principal means of producing reactive species. The number and intensity of SIWs and restrikes are sensitive functions of the alignment of the lattice of dielectric beads (or rods in 2D) with respect to the applied electric field. Decreased spacing between the dielectric elements leads to an increased electric field enhancement in the gas, and therefore locally higher plasma densities, but does not necessarily impact the types of discharges that occur through the lattice.

  20. [Rapid startup and nitrogen removal characteristic of anaerobic ammonium oxidation reactor in packed bed biofilm reactor with suspended carrier].

    Science.gov (United States)

    Chen, Sheng; Sun, De-zhi; Yu, Guang-lu

    2010-03-01

    Packed bed biofilm reactor with suspended carrier was used to cultivate ANAMMOX bacteria with sludge inoculums from WWTP secondary settler. The startup of ANAMMOX reactor was comparatively studied using high nitrogen loading method and low nitrogen loading method with aerobically biofilmed on the carrier, and the nitrogen removal characteristic was further investigated. The results showed that the reactor could be started up successfully within 90 days using low nitrogen loading method, the removal efficiencies of ammonium and nitrite were nearly 100% and the TN removal efficiencywas over 75% , however, the high nitrogen loading method was proved unsuccessfully for startup of ANAMMOX reactor probably because of the inhibition effect of high concentration of ammonium and nitrite. The pH value of effluent was slightly higher than the influent and the pH value can be used as an indicator for the process of ANAMMOX reaction. The packed bed ANAMMOX reactor with suspended carrier showed good characteristics of high nitrogen loading and high removal efficiency, 100% of removal efficiency could be achieved when the influent ammonium and nitrite concentration was lower than 800 mg/L.

  1. Packed-bed reactor/silent-discharge plasma design data report

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-05-01

    In 1992, Congress passed the Federal Facility Compliance Act requiring the U.S. Department of Energy (DOE) to treat and dispose of its mixed waste in accordance with Resource Conservation and Recovery Act (RCRA) land disposal restrictions (LDRs). The DOE Albuquerque Operations Office (AL) currently does not have adequate systems to treat the mixed wastes generated and stored at the nine DOE-AL sites. In response to the need for mixed-waste treatment capacity, DOE-AL organized a Treatment Selection Team under the Mixed-Waste Treatment Program (MWTP) to match mixed wastes with treatment options and develop a strategy for treatment of its mixed waste. The strategy developed by the Treatment Selection Team, as described in the AL Mixed-Waste Treatment Plan (DOE 1994), is to use available off-site commercial treatment facilities for all wastes that can be successfully and cost-effectively treated by such facilities. Where no appropriate commercial treatment facilities exist, mobile treatment units (MTUs) would be developed to treat wastes at the sites where the wastes are generated. Treatment processes used for mixed waste must not only address the hazardous component (i.e., meet LDRs) but also must contain the radioactive component in a form that allows final disposal while protecting workers, the public, and the environment. The packed-bed reactor/silent discharge plasma was chosen as a potential candidate for the treatment of the mixed wastes. The process is described.

  2. Packed-bed reactor/silent-discharge plasma design data report

    International Nuclear Information System (INIS)

    1996-05-01

    In 1992, Congress passed the Federal Facility Compliance Act requiring the U.S. Department of Energy (DOE) to treat and dispose of its mixed waste in accordance with Resource Conservation and Recovery Act (RCRA) land disposal restrictions (LDRs). The DOE Albuquerque Operations Office (AL) currently does not have adequate systems to treat the mixed wastes generated and stored at the nine DOE-AL sites. In response to the need for mixed-waste treatment capacity, DOE-AL organized a Treatment Selection Team under the Mixed-Waste Treatment Program (MWTP) to match mixed wastes with treatment options and develop a strategy for treatment of its mixed waste. The strategy developed by the Treatment Selection Team, as described in the AL Mixed-Waste Treatment Plan (DOE 1994), is to use available off-site commercial treatment facilities for all wastes that can be successfully and cost-effectively treated by such facilities. Where no appropriate commercial treatment facilities exist, mobile treatment units (MTUs) would be developed to treat wastes at the sites where the wastes are generated. Treatment processes used for mixed waste must not only address the hazardous component (i.e., meet LDRs) but also must contain the radioactive component in a form that allows final disposal while protecting workers, the public, and the environment. The packed-bed reactor/silent discharge plasma was chosen as a potential candidate for the treatment of the mixed wastes. The process is described

  3. Hydrogenotrophic denitrification in a packed bed reactor: effects of hydrogen-to-water flow rate ratio.

    Science.gov (United States)

    Lee, J W; Lee, K H; Park, K Y; Maeng, S K

    2010-06-01

    Hydrogen dissolution and hydrogenotrophic denitrification performance were investigated in a lab-scale packed bed reactor (PBR) by varying the hydrogen flow rate and hydraulic retention time (HRT). The denitrification performance was enhanced by increasing the hydrogen flow rate and HRT as a result of high dissolved hydrogen concentration (0.39mg/L) and utilization efficiencies (79%). In this study, the hydrogen-to-water flow rate ratio (Q(g)/Q(w)) was found to be a new operating factor representing the two parameters of hydrogen flow rate and HRT. Hydrogen dissolution and denitrification efficiency were nonlinearly and linearly correlated with the Q(g)/Q(w), respectively. Based on its excellent linear correlation with denitrification efficiency, Q(g)/Q(w) should be greater than 2.3 to meet the WHO's guideline of nitrate nitrogen for drinking water. This study demonstrates that Q(g)/Q(w) is a simple and robust factor to optimize hydrogen-sparged bioreactors for hydrogenotrophic denitrification. Copyright 2010 Elsevier Ltd. All rights reserved.

  4. Thermal and mechanical behaviour of oxygen carrier materials for chemical looping combustion in a packed bed reactor

    International Nuclear Information System (INIS)

    Jacobs, M.; Van Noyen, J.; Larring, Y.; Mccann, M.; Pishahang, M.; Amini, S.; Ortiz, M.; Galluci, F.; Sint-Annaland, M.V.; Tournigant, D.; Louradour, E.; Snijkers, F.

    2015-01-01

    Highlights: • Ilmenite-based oxygen carriers were developed for packed-bed chemical looping. • Addition of Mn_2O_3 increased mechanical strength and microstructure of the carriers. • Oxygen carriers were able to withstand creep and thermal cycling up to 1200 °C. • Ilmenite-based granules are a promising shape for packed-bed reactor conditions. - Abstract: Chemical looping combustion (CLC) is a promising carbon capture technology where cyclic reduction and oxidation of a metallic oxide, which acts as a solid oxygen carrier, takes place. With this system, direct contact between air and fuel can be avoided, and so, a concentrated CO_2 stream is generated after condensation of the water in the exit gas stream. An interesting reactor system for CLC is a packed bed reactor as it can have a higher efficiency compared to a fluidized bed concept, but it requires other types of oxygen carrier particles. The particles must be larger to avoid a large pressure drop in the reactor and they must be mechanically strong to withstand the severe reactor conditions. Therefore, oxygen carriers in the shape of granules and based on the mineral ilmenite were subjected to thermal cycling and creep tests. The mechanical strength of the granules before and after testing was investigated by crush tests. In addition, the microstructure of these oxygen particles was studied to understand the relationship between the physical properties and the mechanical performance. It was found that the granules are a promising shape for a packed bed reactor as no severe degradation in strength was noticed upon thermal cycling and creep testing. Especially, the addition of Mn_2O_3 to the ilmenite, which leads to the formation of an iron–manganese oxide, seems to results in stronger granules than the other ilmenite-based granules.

  5. Packed bed reactor for degradation of simulated cyanide-containing wastewater.

    Science.gov (United States)

    Kumar, Virender; Kumar, Vijay; Bhalla, Tek Chand

    2015-10-01

    The discharge of cyanide-containing effluents into the environment contaminates water bodies and soil. Effective methods of treatment which can detoxify cyanide are the need of the hour. The aim of the present study is to develop a bioreactor for complete degradation of cyanide using immobilized cells of Serratia marcescens RL2b. Alginate-entrapped cells of S. marcescens RL2b were used for complete degradation of cyanide in a packed bed reactor (PBR). Cells grown in minimal salt medium (pH 6.0) were harvested after 20 h and exhibited 0.4 U mg -1  dcw activity and 99 % cyanide degradation in 10 h. These resting cells were entrapped using 3 % alginate beads and packed in a column reactor (20 × 1.7 cm). Simulated cyanide (12 mmol l -1 )-containing wastewater was loaded and fractions were collected after different time intervals at various flow rates. Complete degradation of 12 m mmol l -1 (780 mg l -1 ) cyanide in 10 h was observed at a flow rate of 1.5 ml h -1 . The degradation of cyanide in PBR showed direct dependence on retention time. The retention time of cyanide in the reactor was 9.27 h. The PBR can degrade 1.2 g of cyanide completely in 1 day.

  6. Cyanuric acid biodegradation by a mixed bacterial culture of Agrobacterium tumefaciens and Acinetobacter sp. in a packed bed biofilm reactor.

    Science.gov (United States)

    Galíndez-Nájera, S P; Llamas-Martínez, M A; Ruiz-Ordaz, N; Juárez-Ramírez, C; Mondragón-Parada, M E; Ahuatzi-Chacón, D; Galíndez-Mayer, J

    2009-02-01

    Cyanuric acid (1,3,5-triazine-2,4,6-triol [OOOT]) is a common biodegradation byproduct of triazinic herbicides, frequently accumulated in soils or water when supplementary carbon sources are absent. A binary bacterial culture able to degrade OOOT was selected through a continuous selection process accomplished in a chemostat fed with a mineral salt (MS) medium containing cyanuric acid as the sole carbon and nitrogen source. By sequence comparison of their 16S rDNA amplicons, bacterial strains were identified as Agrobacterium tumefaciens, and Acinetobacter sp. When the binary culture immobilized in a packed bed reactor (PBR) was fed with MS medium containing OOOT (50 mg L(-1)), its removal efficiencies were about 95%; when it was fed with OOOT plus glucose (120 mg L(-1)) as a supplementary carbon source, its removal efficiencies were closer to 100%. From sessile cells, attached to PBR porous support, or free cells present in the outflowing medium, DNA was extracted and used for Random Amplification of Polymorphic DNA analysis. Electrophoretic patterns obtained were compared to those of pure bacterial strains, a clear predominance of A. tumefaciens in PBR was observed. Although in continuous suspended cell culture, a stable binary community could be maintained, the attachment capability of A. tumefaciens represented a selective advantage over Acinetobacter sp. in the biofilm reactor, favoring its predominance in the porous stone support.

  7. Green synthesis of isopropyl myristate in novel single phase medium Part II: Packed bed reactor (PBR) studies

    OpenAIRE

    Vadgama, Rajeshkumar N.; Odaneth, Annamma A.; Lali, Arvind M.

    2015-01-01

    Isopropyl myristate is a useful functional molecule responding to the requirements of numerous fields of application in cosmetic, pharmaceutical and food industry. In the present work, lipase-catalyzed production of isopropyl myristate by esterification of myristic acid with isopropyl alcohol (molar ratio of 1:15) in the homogenous reaction medium was performed on a bench-scale packed bed reactors, in order to obtain suitable reaction performance data for upscaling. An immobilized lipase B fr...

  8. Storage capacity assessment of liquid fuels production by solar gasification in a packed bed reactor using a dynamic process model

    International Nuclear Information System (INIS)

    Kaniyal, Ashok A.; Eyk, Philip J. van; Nathan, Graham J.

    2016-01-01

    Highlights: • First analysis to assess storage requirements of a stand-alone packed bed, batch process solar gasifier. • 35 days of storage required for stand-alone solar system, whereas 8 h of storage required for hybrid system. • Sensitivity of storage requirement to reactor operation, solar region and solar multiple evaluated. - Abstract: The first multi-day performance analysis of the feasibility of integrating a packed bed, indirectly irradiated solar gasification reactor with a downstream FT liquids production facility is reported. Two fuel-loading scenarios were assessed. In one, the residual unconverted fuel at the end of a day is reused, while in the second, the residual fuel is discarded. To estimate a full year time-series of operation, a simplified statistical model was developed from short-period simulations of the 1-D heat transfer, devolatilisation and gasification chemistry model of a 150 kW th packed bed reactor (based on the authors’ earlier work). The short time-series cover a variety of solar conditions to represent seasonal, diurnal and cloud-induced solar transience. Also assessed was the influence of increasing the solar flux incident at the emitter plate of the packed bed reactor on syngas production. The combination of the annual time-series and daily model of syngas production was found to represent reasonably the seasonal transience in syngas production. It was then used to estimate the minimum syngas storage volume required to maintain a stable flow-rate and composition of syngas to a FT reactor over a full year of operation. This found that, for an assumed heliostat field collection area of 1000 m 2 , at least 64 days of storage is required, under both the Residual Fuel Re-Use and Discard scenarios. This figure was not sensitive to the two solar sites assessed, Farmington, New Mexico or Tonopah Airport, Nevada. Increasing the heliostat field collection area from 1000 to 1500 m 2 , led to an increase in the calculated daily rate

  9. Supported Photocatalyst for Removal of Emerging Contaminants from Wastewater in a Continuous Packed-Bed Photoreactor Configuration

    Directory of Open Access Journals (Sweden)

    Mª Emma Borges

    2015-02-01

    Full Text Available Water pollution from emerging contaminants (ECs or emerging pollutants is an important environmental problem. Heterogeneous photocatalytic treatment, as advanced oxidation treatment of wastewater effluents, has been proposed to solve this problem. In this paper, a heterogeneous photocatalytic process was studied for emergent contaminants removal using paracetamol as a model contaminant molecule. TiO2 photocatalytic activity was evaluated using two photocatalytic reactor configurations: Photocatalyst solid suspension in wastewater in a stirred photoreactor and TiO2 supported on glass spheres (TGS configuring a packed bed photoreactor. The surface morphology and texture of the TGS were monitored by scanning electron microscope (SEM. The influence of photocatalyst amount and wastewater pH were evaluated in the stirred photoreactor and the influence of wastewater flowrate was tested in the packed bed photoreactor, in order to obtain the optimal operation conditions. Moreover, results obtained were compared with those obtained from photolysis and adsorption studies, using the optimal operation conditions. Good photocatalytic activities have been observed and leads to the conclusion that the heterogeneous photocatalytic system in a packed bed is an effective method for removal of emerging pollutants.

  10. Process engineering and optimization of glycerol separation in a packed-bed reactor for enzymatic biodiesel production.

    Science.gov (United States)

    Hama, Shinji; Tamalampudi, Sriappareddy; Yoshida, Ayumi; Tamadani, Naoki; Kuratani, Nobuyuki; Noda, Hideo; Fukuda, Hideki; Kondo, Akihiko

    2011-11-01

    A process model for efficient glycerol separation during methanolysis in an enzymatic packed-bed reactor (PBR) was developed. A theoretical glycerol removal efficiency from the reaction mixture containing over 30% methyl esters was achieved at a high flow rate of 540 ml/h. To facilitate a stable operation of the PBR system, a batch reaction prior to continuous methanolysis was conducted using oils with different acid values and immobilized lipases pretreated with methyl esters. The reaction system successfully attained the methyl ester content of over 30% along with reduced viscosity and water content. Furthermore, to obtain a high methyl ester content above 96% continuously, long-term lipase stability was confirmed by operating a bench-scale PBR system for 550 h, in which the intermediates containing methyl esters and residual glycerides were fed into the enzyme-packed columns connected in series. Therefore, the developed process model is considered useful for industrial biodiesel production. Copyright © 2011 Elsevier Ltd. All rights reserved.

  11. Biodegradation of 4-bromophenol by Arthrobacter chlorophenolicus A6T in a newly designed packed bed reactor.

    Science.gov (United States)

    Sahoo, Naresh Kumar; Ghosh, Pranab Kumar; Pakshirajan, Kannan

    2013-02-01

    Bromophenol is listed as a priority pollutant by the U.S. EPA. However, there has been no report on the removal of bromophenol in any biological system that is operated in a continuous mode. The efficiency of Arthrobacter chlorophenolicus A6(T) on the biodegradation of 4-bromophenol (4-BP) in a newly designed packed bed reactor (PBR) was evaluated with different influent 4-BP concentrations between 400 mg l(-1) and 1200 mg l(-1) and hydraulic retention times (HRTs) between 24 h and 7.5 h. The response of the PBR to 4-BP shock loadings was also tested, and the bioreactor was found to adequately handle these shock loadings. The percentage of effluent toxicity in the PBR was tested using mixed microbial consortia as the test species; this experiment was performed using a 4-BP influent concentration of 1200 mg l(-1) and HRTs between 24 h and 7.5 h. A maximal 98% effluent toxicity removal was achieved when the PBR was operated at an HRT of 24 h. In the present study, 4-BP was used as the sole source of carbon and energy, and the complete removal of 4-BP was achieved with 4-BP loading rates of up to 2277 mg l(-1) day(-1). Copyright © 2012 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

  12. Improved thermostable polyvinyl alcohol electrospun nanofibers with entangled naringinase used in a novel mini-packed bed reactor.

    Science.gov (United States)

    Nunes, Mário A P; Martins, Samuel; Rosa, M Emilia; Gois, Pedro M P; Fernandes, Pedro C B; Ribeiro, Maria H L

    2016-08-01

    Polyvinyl alcohol (PVA) electrospun nanofibers were produced using an electrospinning technique. Key parameters (e.g. collectors, distance from needle tip to collector, among others) that influence the structure and morphology of fibers were optimized. The naringinase entrapped in PVA nanofibers retained over 100% of its initial activity after 212h of operation, at 25°C. Chemical crosslinking with several boronic acids further increased the hydrolysis temperature (up to 85°C) and yielded nanofibers with thermal stability up to 121°C. A mini packed bed reactor (PBR) developed to establish the feasibility for continuous enzymatic operation, ran for 16days at 45°C. Highest naringenin biosynthesis was attained at a flow rate of 10mLh(-1). Highest volumetric (78molL(-1)h(-1)) and specific (26molh(-1)genzyme(-1)) productivities were attained at 30mLh(-1). The activity of NGase in electrospun nanofibers remained constant for almost 16days of operation at 10mLh(-1). Copyright © 2016 Elsevier Ltd. All rights reserved.

  13. Performances and microbial features of an aerobic packed-bed biofilm reactor developed to post-treat an olive mill effluent from an anaerobic GAC reactor

    Directory of Open Access Journals (Sweden)

    Marchetti Leonardo

    2006-04-01

    Full Text Available Abstract Background Olive mill wastewater (OMW is the aqueous effluent of olive oil producing processes. Given its high COD and content of phenols, it has to be decontaminated before being discharged. Anaerobic digestion is one of the most promising treatment process for such an effluent, as it combines high decontamination efficiency with methane production. The large scale anaerobic digestion of OMWs is normally conducted in dispersed-growth reactors, where however are generally achieved unsatisfactory COD removal and methane production yields. The possibility of intensifying the performance of the process using a packed bed biofilm reactor, as anaerobic treatment alternative, was demonstrated. Even in this case, however, a post-treatment step is required to further reduce the COD. In this work, a biological post-treatment, consisting of an aerobic biological "Manville" silica bead-packed bed aerobic reactor, was developed, tested for its ability to complete COD removal from the anaerobic digestion effluents, and characterized biologically through molecular tools. Results The aerobic post-treatment was assessed through a 2 month-continuous feeding with the digested effluent at 50.42 and 2.04 gl-1day-1 of COD and phenol loading rates, respectively. It was found to be a stable process, able to remove 24 and 39% of such organic loads, respectively, and to account for 1/4 of the overall decontamination efficiency displayed by the anaerobic-aerobic integrated system when fed with an amended OMW at 31.74 and 1.70 gl-1day-1 of COD and phenol loading rates, respectively. Analysis of 16S rRNA gene sequences of biomass samples from the aerobic reactor biofilm revealed that it was colonized by Rhodobacterales, Bacteroidales, Pseudomonadales, Enterobacteriales, Rhodocyclales and genera incertae sedis TM7. Some taxons occurring in the influent were not detected in the biofilm, whereas others, such as Paracoccus, Pseudomonas, Acinetobacter and Enterobacter

  14. Rice Husk Packed Bed Column Reactor To Remove Cadmium From Landfill Leachate

    Directory of Open Access Journals (Sweden)

    Monik Kasman

    2014-06-01

    Full Text Available The landfill leachate can be a major problem due to large variability of high organic, inorganic, heavy metal content and toxicity characteristics from landfill leachate such as  cadmium. Thus, this study was aimed to observe the application of rice husk packed bed column to reduce cadmium from landfill leachate. Experiment was conducted in gravity down flow system by pumping landfill leachate into packed bed column. The effect of influent flow rate to adsorption capacity was studied by varying flow rate (5 mL/min and 10 mL/min. The effluent-influent concentration ratio Ce/C0 (% as a function of throughput volume (L was used to represent the breakthrough curve in column systems. Result shows that the flow rate of 5 mL/min was favorable to achieve higher removal rates with the percentage of cadmium was 57 %. At breakthrough time, the cadmium effluent concentration reached on 0.01 mg/l for both of flow rate.ABSTRAKLindi yang dihasilkan dari TPA (Tempat Pembuangan Akhir menimbulkan permasalahan lingkungan karena kandungan pencemarnya meliputi material organik, material anorganik, logam dan material beracun. Salah satu logam berat yang terdapat dalam lindi tersebut adalah kadmium. Penelitian ini bertujuan untuk mereduksi kadmium dalam lindi dengan menggunakan sekam padi yang diinstal dalam packed bed column. Lindi dipompakan dari tangki penampung lindi ke dalam packed bed column dan dialirkan dari atas ke bawah kolom secara gravitasi. Fokus pada penelitian ini adalah pengaruh laju alir influen terhadap kapasitas adsorpsi. Dimana lindi dialirkan dengan laju alir 5 mL/menit dan 10 mL/menit. Kurva breakthrough (titik jenuh kolom dipresentasikan oleh hubungan antara rasio konsentrasi efluen-influen Ce/C0 (% dan jumlah aliran lindi yang diolah dalam kolom. Hasil eksperimen menunjukkan bahwa persentase reduksi tertinggi dicapai pada laju alir 5 mL/menit yaitu 57%. Waktu jenuh kedua laju alir (5 mL/menit dan 10 mL/menit tercapai saat konsentrasi efluen

  15. External Mass Transfer Model for Hydrogen Peroxide Decomposition by Terminox Ultra Catalase in a Packed-Bed Reactor

    Directory of Open Access Journals (Sweden)

    Grubecki Ireneusz

    2017-06-01

    Full Text Available It is known that external diffusional resistances are significant in immobilized enzyme packed-bed reactors, especially at large scales. Thus, the external mass transfer effects were analyzed for hydrogen peroxide decomposition by immobilized Terminox Ultra catalase in a packed-bed bioreactor. For this purpose the apparent reaction rate constants, kP, were determined by conducting experimental works at different superficial velocities, U, and temperatures. To develop an external mass transfer model the correlation between the Colburn factor, JD, and the Reynolds number, Re, of the type JD = K Re(n-1 was assessed and related to the mass transfer coefficient, kmL. The values of K and n were calculated from the dependence (am kp-1 - kR-1 vs. Re-1 making use of the intrinsic reaction rate constants, kR, determined before. Based on statistical analysis it was found that the mass transfer correlation JD = 0.972 Re-0.368 predicts experimental data accurately. The proposed model would be useful for the design and optimization of industrial-scale reactors.

  16. Biosorption of lead(II) and cadmium(II) by protonated Sargassum glaucescens biomass in a continuous packed bed column

    International Nuclear Information System (INIS)

    Naddafi, Kazem; Nabizadeh, Ramin; Saeedi, Reza; Mahvi, Amir Hossein; Vaezi, Forough; Yaghmaeian, Kamyar; Ghasri, Azar; Nazmara, Shahrokh

    2007-01-01

    Biosorption of lead(II) and cadmium(II) from aqueous solutions by protonated Sargassum glaucescens biomass was studied in a continuous packed bed column. The selective uptake of Pb 2+ and Cd 2+ was investigated in a binary system with initial concentration of 1 mM for each metal ion. The selective uptake capacities of Pb 2+ and Cd 2+ at complete exhaustion point were obtained 1.18 and 0.22 mmol/g, respectively; therefore, the biosorbent showed much higher relative affinity for Pb 2+ than for Cd 2+ . The optimum range of empty bed contact time (EBCT) was identified as 5-10 min in the packed bed column. The efficiency of biosorbent regeneration by 0.1 M HCl was achieved about 60%, so that the maximum uptake capacity of Pb 2+ by the regenerated biomass was determined to be 0.75 mmol/g while the same value for the original biomass was 1.24 mmol/g. The Thomas model was found in a suitable fitness with the experimental data (R 2 > 0.90 and ε% + with the uptake of heavy metals; hence, ion exchange was confirmed to be one of the main biosorption mechanisms

  17. Oxygen distribution in packed-bed membrane reactors for partial oxidations: effect of the radial porosity profiles on the product selectivity

    NARCIS (Netherlands)

    Kurten, U.; van Sint Annaland, M.; Kuipers, J.A.M.

    2004-01-01

    A two-dimensional, pseudohomogeneous reactor model was presented to describe the radial and axial concentration profiles in a packed-bed membrane reactor and the local velocity field while accounting for the influences due to the distributive membrane flow and the radial porosity profile. The effect

  18. Biodegradation of p-nitrophenol using Arthrobacter chlorophenolicus A6 in a novel upflow packed bed reactor.

    Science.gov (United States)

    Sahoo, Naresh Kumar; Pakshirajan, Kannan; Ghosh, Pranab Kumar

    2011-06-15

    A novel packed bed reactor (PBR) was designed with cross flow aeration at multiple ports along the depth to improve the hydrodynamic conditions of the reactor, and the biodegradation efficiency of Arthrobacter chlorophenolicus A6 on p-nitrophenol (PNP) removal in PBR at different PNP loading rates were evaluated. The novel PBR was designed to improve the hydrodynamic features such as mixing time profile (t(m95)), oxygen mass transfer coefficient (k(L)a), and overall gas hold up capacity (ɛ(G)) of the reactor. PNP concentration in the influent was varied between 600 and 1400 mg l(-1) whereas the hydraulic retention time (HRT) in the reactor was varied between 18 and 7.5h. Complete removal of PNP was achieved in the reactor up to a PNP loading rate of 2787 mg l(-1)d(-1). More than 99.9% removal of PNP was achieved in the reactor for an influent concentration of 1400 mg l(-1) and at 18 h HRT. In the present study, PNP was utilized as sole source of carbon and energy by A. chlorophenolicus A6. Furthermore, the bioreactor showed good compatibility in handling shock loading of PNP. Copyright © 2011 Elsevier B.V. All rights reserved.

  19. Biodegradation of p-nitrophenol using Arthrobacter chlorophenolicus A6 in a novel upflow packed bed reactor

    International Nuclear Information System (INIS)

    Sahoo, Naresh Kumar; Pakshirajan, Kannan; Ghosh, Pranab Kumar

    2011-01-01

    A novel packed bed reactor (PBR) was designed with cross flow aeration at multiple ports along the depth to improve the hydrodynamic conditions of the reactor, and the biodegradation efficiency of Arthrobacter chlorophenolicus A6 on p-nitrophenol (PNP) removal in PBR at different PNP loading rates were evaluated. The novel PBR was designed to improve the hydrodynamic features such as mixing time profile (t m95 ), oxygen mass transfer coefficient (k L a), and overall gas hold up capacity (ε G ) of the reactor. PNP concentration in the influent was varied between 600 and 1400 mg l -1 whereas the hydraulic retention time (HRT) in the reactor was varied between 18 and 7.5 h. Complete removal of PNP was achieved in the reactor up to a PNP loading rate of 2787 mg l -1 d -1 . More than 99.9% removal of PNP was achieved in the reactor for an influent concentration of 1400 mg l -1 and at 18 h HRT. In the present study, PNP was utilized as sole source of carbon and energy by A. chlorophenolicus A6. Furthermore, the bioreactor showed good compatibility in handling shock loading of PNP.

  20. Transformation of 1,1,1-trichloroethane in an anaerobic packed-bed reactor at various concentrations of 1,1,1-trichloroethane, acetate and sulfate

    NARCIS (Netherlands)

    deBest, JH; Jongema, H; Weijling, A; Doddema, HJ; Janssen, DB; Harder, W

    Biotransformation of 1,1,1-trichloroethane (CH3CCl3) was observed in an anaerobic packed-bed reactor under conditions of both sulfate reduction and methanogenesis. Acetate (1 mM) served as an electron donor. CH3CCl3 was completely converted up to the highest investigated concentration of 10 mu M.

  1. Effect of mass-transport limitations on the performance of a packed bed membrane reactor for partial oxidations. Intraparticle mass transport

    NARCIS (Netherlands)

    Sint Annaland, van M.; Kurten, U.; Kuipers, J.A.M.

    2007-01-01

    For partial oxidation systems, where the reaction order in oxygen of the formation rate of the target product is smaller than the reaction order in oxygen of the consecutive reaction rate toward the waste product, a packed bed membrane reactor can be applied to distributively dose oxygen along the

  2. Effect of Mass-Transport Limitations on the Performance of a Packed Bed Membrane Reactor for Partial Oxidations. Intraparticle Mass Transport

    NARCIS (Netherlands)

    van Sint Annaland, M.; Kurten, U.; Kuipers, J.A.M.

    2007-01-01

    For partial oxidation systems, where the reaction order in oxygen of the formation rate of the target product is smaller than the reaction order in oxygen of the consecutive reaction rate toward the waste product, a packed bed membrane reactor can be applied to distributively dose oxygen along the

  3. Hydrogenation of Levulinic Acid to gamma-Valerolactone in Water Using Millimeter Sized Supported Ru Catalysts in a Packed Bed Reactor

    NARCIS (Netherlands)

    Piskun, A. S.; de Haan, J. E.; Wilbers, E.; de Bovenkamp, H. H. van; Tang, Z.; Heeres, Hero

    gamma-Valerolactone (GVL) has been identified as a sustainable platform chemical for the production of carbon-based chemicals. We here report an experimental study on the catalytic hydrogenation of levulinic acid (LA) in water to GVL in a packed bed reactor using supported Ru catalysts (carbon,

  4. Three-phase packed bed reactor with an evaporating solvent—I. Experimental: the hydrogenation of 2,4,6-trinitrotoluene in methanol

    NARCIS (Netherlands)

    van Gelder, K.B.; Damhof, J.K.; Kroijenga, P.J.; Westerterp, K.R.

    1990-01-01

    In this paper we present experimental data on the three-phase hydrogenation of 2,4,6-trinitrotoluene (TNT) to triaminotoluene. The experiments are performed in a cocurrent upflow packed bed reactor. Methanol is used as an evaporating solvent. The influence of the main operating parameters, the

  5. A packed bed membrane reactor for the oxidative dehydrogenation of propane on a Ga2O3 / MoO3 based catalyst

    NARCIS (Netherlands)

    Kotanjac, Ž.S.; Sint Annaland, van M.; Kuipers, J.A.M.

    2010-01-01

    Oxidative dehydrogenation of propane has been studied over a Ga2O3/MoO3 based catalyst. Using a differentially operated packed bed reactor with premixed oxygen and propane feed, the kinetic parameters for the main reaction and the consecutive and parallel reactions were experimentally determined. It

  6. Aerobic biodegradation of 2,4-DNT and 2,6-DNT: Performance characteristics and biofilm composition changes in continuous packed-bed bioreactors

    International Nuclear Information System (INIS)

    Paca, J.; Halecky, M.; Barta, J.; Bajpai, R.

    2009-01-01

    This manuscript deals with continuous experiments for biodegradation of individual dinitrotoluenes by a defined mixed culture in packed-bed reactors (PBRs) containing either poraver or fire-clay as packing material. Removal efficiencies and volumetric biodegradation rates were measured as a function of the loading rate of 2,4-dinitrotoluene (2,4-DNT) and 2,6-dinitrotoluene (2,6-DNT) under steady-state conditions. The poraver reactor showed higher removal efficiencies for both the DNTs. The removal efficiency for 2,4-DNT remained greater than 90% in the poraver reactor whereas it dropped steadily from 85 to 65% in the fire-clay reactor as the organic loading rates were increased from 19 to 60 mg L -1 day -1 . Similar trends were seen for the volumetric degradation rate as well. In both the reactors, 2,4-DNT degraded more effectively than 2,6-DNT. The microbial consortium was characterized both in the inoculum as well as in the operating PBR. Cell numbers per gram dry packing material were similar in the two reactors. However, there was a distinct difference in the nature of microorganisms that were found in the two packings. The fire-clay contained a larger number of cells that were not primary degraders of DNTs

  7. Aerobic biodegradation of 2,4-DNT and 2,6-DNT: performance characteristics and biofilm composition changes in continuous packed-bed bioreactors.

    Science.gov (United States)

    Paca, J; Halecky, M; Barta, J; Bajpai, R

    2009-04-30

    This manuscript deals with continuous experiments for biodegradation of individual dinitrotoluenes by a defined mixed culture in packed-bed reactors (PBRs) containing either poraver or fire-clay as packing material. Removal efficiencies and volumetric biodegradation rates were measured as a function of the loading rate of 2,4-dinitrotoluene (2,4-DNT) and 2,6-dinitrotoluene (2,6-DNT) under steady-state conditions. The poraver reactor showed higher removal efficiencies for both the DNTs. The removal efficiency for 2,4-DNT remained greater than 90% in the poraver reactor whereas it dropped steadily from 85 to 65% in the fire-clay reactor as the organic loading rates were increased from 19 to 60 mg L(-1)day(-1). Similar trends were seen for the volumetric degradation rate as well. In both the reactors, 2,4-DNT degraded more effectively than 2,6-DNT. The microbial consortium was characterized both in the inoculum as well as in the operating PBR. Cell numbers per gram dry packing material were similar in the two reactors. However, there was a distinct difference in the nature of microorganisms that were found in the two packings. The fire-clay contained a larger number of cells that were not primary degraders of DNTs.

  8. Fungi solubilisation of low rank coal: performances of stirred tank, fluidised bed and packed bed reactors

    CSIR Research Space (South Africa)

    Oboirien, BO

    2013-02-01

    Full Text Available Coal biosolubilisation was investigated in stirred tank reactor, fluidised bed and fixed bed bioreactors with a view to highlight the advantages and shortcomings of each of these reactor configurations. The stirred aerated bioreactor and fluidised...

  9. Effects of pulse-to-pulse residual species on discharges in repetitively pulsed discharges through packed bed reactors

    Science.gov (United States)

    Kruszelnicki, Juliusz; Engeling, Kenneth W.; Foster, John E.; Kushner, Mark J.

    2016-09-01

    Atmospheric pressure dielectric barrier discharges (DBDs) sustained in packed bed reactors (PBRs) are being investigated for conversion of toxic and waste gases, and CO2 removal. These discharges are repetitively pulsed having varying flow rates and internal geometries, which results in species from the prior pulse still being in the discharge zone at the time the following discharge pulse occurs. A non-negligible residual plasma density remains, which effectively acts as preionization. This residual charge changes the discharge properties of subsequent pulses, and may impact important PBR properties such as chemical selectivity. Similarly, the residual neutral reactive species produced during earlier pulses will impact the reaction rates on subsequent pulses. We report on results of a computational investigation of a 2D PBR using the plasma hydrodynamics simulator nonPDPSIM. Results will be discussed for air flowing though an array of dielectric rods at atmospheric pressure. The effects of inter-pulse residual species on PBR discharges will be quantified. Means of controlling the presence of residual species in the reactor through gas flow rate, pulse repetition, pulse width and geometry will be described. Comparisons will be made to experiments. Work supported by US DOE Office of Fusion Energy Science and the National Science Foundation.

  10. A two-stage ethanol-based biodiesel production in a packed bed reactor

    DEFF Research Database (Denmark)

    Xu, Yuan; Nordblad, Mathias; Woodley, John

    2012-01-01

    were conducted in a simulated series of reactors by repeatedly passing the reaction mixture through a single reactor, with separation of the by-product glycerol and water between passes in the first and second stages, respectively. The second stage brought the major components of biodiesel to ‘in......-spec’ levels according to the European biodiesel specifications for methanol-based biodiesel. The highest overall productivity achieved in the first stage was 2.52 kg FAEE(kg catalyst)−1 h−1 at a superficial velocity of 7.6 cm min−1, close to the efficiency of a stirred tank reactor under similar conditions...

  11. Efficient preparation of enantiopure D-phenylalanine through asymmetric resolution using immobilized phenylalanine ammonia-lyase from Rhodotorula glutinis JN-1 in a recirculating packed-bed reactor.

    Directory of Open Access Journals (Sweden)

    Longbao Zhu

    Full Text Available An efficient enzymatic process was developed to produce optically pure D-phenylalanine through asymmetric resolution of the racemic DL-phenylalanine using immobilized phenylalanine ammonia-lyase (RgPAL from Rhodotorula glutinis JN-1. RgPAL was immobilized on a modified mesoporous silica support (MCM-41-NH-GA. The resulting MCM-41-NH-GA-RgPAL showed high activity and stability. The resolution efficiency using MCM-41-NH-GA-RgPAL in a recirculating packed-bed reactor (RPBR was higher than that in a stirred-tank reactor. Under optimal operational conditions, the volumetric conversion rate of L-phenylalanine and the productivity of D-phenylalanine reached 96.7 mM h⁻¹ and 0.32 g L⁻¹ h⁻¹, respectively. The optical purity (eeD of D-phenylalanine exceeded 99%. The RPBR ran continuously for 16 batches, the conversion ratio did not decrease. The reactor was scaled up 25-fold, and the productivity of D-phenylalanine (eeD>99% in the scaled-up reactor reached 7.2 g L⁻¹ h⁻¹. These results suggest that the resolution process is an alternative method to produce highly pure D-phenylalanine.

  12. Efficient preparation of enantiopure D-phenylalanine through asymmetric resolution using immobilized phenylalanine ammonia-lyase from Rhodotorula glutinis JN-1 in a recirculating packed-bed reactor.

    Science.gov (United States)

    Zhu, Longbao; Zhou, Li; Huang, Nan; Cui, Wenjing; Liu, Zhongmei; Xiao, Ke; Zhou, Zhemin

    2014-01-01

    An efficient enzymatic process was developed to produce optically pure D-phenylalanine through asymmetric resolution of the racemic DL-phenylalanine using immobilized phenylalanine ammonia-lyase (RgPAL) from Rhodotorula glutinis JN-1. RgPAL was immobilized on a modified mesoporous silica support (MCM-41-NH-GA). The resulting MCM-41-NH-GA-RgPAL showed high activity and stability. The resolution efficiency using MCM-41-NH-GA-RgPAL in a recirculating packed-bed reactor (RPBR) was higher than that in a stirred-tank reactor. Under optimal operational conditions, the volumetric conversion rate of L-phenylalanine and the productivity of D-phenylalanine reached 96.7 mM h⁻¹ and 0.32 g L⁻¹ h⁻¹, respectively. The optical purity (eeD) of D-phenylalanine exceeded 99%. The RPBR ran continuously for 16 batches, the conversion ratio did not decrease. The reactor was scaled up 25-fold, and the productivity of D-phenylalanine (eeD>99%) in the scaled-up reactor reached 7.2 g L⁻¹ h⁻¹. These results suggest that the resolution process is an alternative method to produce highly pure D-phenylalanine.

  13. Stability of immobilized Rhizomucor miehei lipase for the synthesis of pentyl octanoate in a continuous packed bed bioreactor

    Directory of Open Access Journals (Sweden)

    E. Skoronski

    2014-09-01

    Full Text Available The enzymatic synthesis of organic compounds in continuous bioreactors is an efficient way to obtain industrially important chemicals. However, few works have focused on the study of the operational conditions and the bioprocess performance. In this work, the aliphatic ester pentyl octanoate was obtained by direct esterification using a continuous packed bed bioreactor containing the immobilized enzyme Lipozyme® RM IM as catalyst. Enzymatic deactivation was evaluated under different conditions for the operational parameters substrate/enzyme ratio (5.00, 1.67, 0.83 and 0.55 mmol substrate∙min-1∙g-1enzyme and temperature (30, 40, 50 and 60 °C. The optimal condition was observed at 30 ºC, which gave the minimum enzymatic deactivation rate and the maximum conversion to the desired product, yielding approximately 60 mmols of ester for an enzyme loading of 0.5 g into the bioreactor. A first-order deactivation model showed good agreement with the experimental data.

  14. Performance of a pilot-scale packed bed reactor for perchlorate reduction using a sulfur oxidizing bacterial consortium.

    Science.gov (United States)

    Boles, Amber R; Conneely, Teresa; McKeever, Robert; Nixon, Paul; Nüsslein, Klaus R; Ergas, Sarina J

    2012-03-01

    A novel sulfur-utilizing perchlorate reducing bacterial consortium successfully treated perchlorate (ClO₄⁻) in prior batch and bench-scale packed bed reactor (PBR) studies. This study examined the scale up of this process for treatment of water from a ClO ₄⁻ and RDX contaminated aquifer in Cape Cod Massachusetts. A pilot-scale upflow PBR (∼250-L) was constructed with elemental sulfur and crushed oyster shell packing media. The reactor was inoculated with sulfur oxidizing ClO₄⁻ reducing cultures enriched from a wastewater seed. Sodium sulfite provided a good method of dissolved oxygen removal in batch cultures, but was found to promote the growth of bacteria that carry out sulfur disproportionation and sulfate reduction, which inhibited ClO₄⁻ reduction in the pilot system. After terminating sulfite addition, the PBR successfully removed 96% of the influent ClO₄⁻ in the groundwater at an empty bed contact time (EBCT) of 12 h (effluent ClO₄⁻ of 4.2 µg L(-1)). Simultaneous ClO₄⁻ and NO₃⁻ reduction was observed in the lower half of the reactor before reactions shifted to sulfur disproportionation and sulfate reduction. Analyses of water quality profiles were supported by molecular analysis, which showed distinct groupings of ClO₄⁻ and NO₃⁻ degrading organisms at the inlet of the PBR, while sulfur disproportionation was the primary biological process occurring in the top potion of the reactor. Copyright © 2011 Wiley Periodicals, Inc.

  15. Modeling of an axial flow, spherical packed-bed reactor for naphtha reforming process in the presence of the catalyst deactivation

    Energy Technology Data Exchange (ETDEWEB)

    Iranshahi, D.; Pourazadi, E.; Paymooni, K.; Bahmanpour, A.M.; Rahimpour, M.R.; Shariati, A. [Department of Chemical Engineering, School of Chemical and Petroleum Engineering, Shiraz University, Shiraz 71345 (Iran, Islamic Republic of)

    2010-12-15

    Improving the octane number of the aromatics' compounds has always been an important matter in refineries and lots of investigations have been made concerning this issue. In this study, an axial-flow spherical packed-bed reactor (AF-SPBR) is considered for naphtha reforming process in the presence of catalyst deactivation. Model equations are solved by the orthogonal collocation method. The AF-SPBR results are compared with the plant data of a conventional tubular packed-bed reactor (TR). The effects of some important parameters such as pressure and temperature on aromatic and hydrogen production rates and catalyst activity have been investigated. Higher production rates of aromatics can successfully be achieved in this novel reactor. Moreover, results show the capability of flow augmentation in the proposed configuration in comparison with the TR. This study shows the superiority of AF-SPBR configuration to the conventional types. (author)

  16. Studies on Pyrolysis Kinetic of Newspaper Wastes in a Packed Bed Reactor: Experiments, Modeling, and Product Characterization

    Directory of Open Access Journals (Sweden)

    Aparna Sarkar

    2015-01-01

    Full Text Available Newspaper waste was pyrolysed in a 50 mm diameter and 640 mm long reactor placed in a packed bed pyrolyser from 573 K to 1173 K in nitrogen atmosphere to obtain char and pyro-oil. The newspaper sample was also pyrolysed in a thermogravimetric analyser (TGA under the same experimental conditions. The pyrolysis rate of newspaper was observed to decelerate above 673 K. A deactivation model has been attempted to explain this behaviour. The parameters of kinetic model of the reactions have been determined in the temperature range under study. The kinetic rate constants of volatile and char have been determined in the temperature range under study. The activation energies 25.69 KJ/mol, 27.73 KJ/mol, 20.73 KJ/mol and preexponential factors 7.69 min−1, 8.09 min−1, 0.853 min−1 of all products (solid reactant, volatile, and char have been determined, respectively. A deactivation model for pyrolysis of newspaper has been developed under the present study. The char and pyro-oil obtained at different pyrolysis temperatures have been characterized. The FT-IR analyses of pyro-oil have been done. The higher heating values of both pyro-products have been determined.

  17. A thermal packed-bed reactor and a silent discharge plasma cell for a two-stage treatment system

    International Nuclear Information System (INIS)

    Godoy-Cabrera, O G; Lopez-Callejas, R; Mercado-Cabrera, A; Barocio, S R; Valencia, R; Munoz-Castro, A; Eguiluz, R Pena; Piedad-Beneitez, A de la

    2006-01-01

    Dielectric barrier discharge cells (DBDCs) have proved their efficiency in the generation of cold plasmas for hazardous organic compound degradation. Here, we describe the design and construction of a dual thermal packed-bed reactor and DBDC-based system to carry out the degradation of hazardous organic compounds in both liquid and gas phases. The main components of this system are: (i) the thermal treatment system (ii) DBDC and (iii) resonant inverters of low (3.3 kHz) and high (100 kHz) calculated frequencies. The definition of the cell physical parameters considers: (a) a first-order degradation ratio of the compound and (b) the air breakdown at atmospheric pressure as a function of the transport carrier gas. The power consumed by the cells during the discharges was computed theoretically and experimentally. Using the dual system along with a gas chromatography diagnostic system, highly efficient degradations of a test compound (benzene) have been obtained, reaching 99.950% in the case of a cell experimentally operated at 3.3 kHz and up to 99.996% in another one at 94.3 kHz. An additional 3.7 times reduction in the latter case residence time with respect to the low frequency cell has been found

  18. A systems CFD model of a packed bed high temperature gas-cooled nuclear reactor

    International Nuclear Information System (INIS)

    Du Toit, C.G.; Rousseau, P.G.; Greyvenstein, G.P.; Landman, W.A.

    2006-01-01

    The theoretical basis and conceptual formulation of a comprehensive reactor model to simulate the thermal-fluid phenomena of the PBMR reactor core and core structures is given. Through a rigorous analysis the fundamental equations are recast in a form that is suitable for incorporation in a systems CFD code. The formulation of the equations results in a collection of one-dimensional elements (models) that can be used to construct a comprehensive multi-dimensional network model of the reactor. The elements account for the pressure drop through the reactor; the convective heat transport by the gas; the convection heat transfer between the gas and the solids; the radiative, contact and convection heat transfer between the pebbles and the heat conduction in the pebbles. Results from the numerical model are compared with that of experiments conducted on the SANA facility covering a range of temperatures as well as two different fluids and different heating configurations. The good comparison obtained between the simulated and measured results show that the systems CFD approach sufficiently accounts for all of the important phenomena encountered in the quasi-steady natural convection driven flows that will prevail after critical events in a reactor. The fact that the computer simulation time for all of the simulations was less than three seconds on a standard notebook computer also indicates that the new model indeed achieves a fine balance between accuracy and simplicity. The new model can therefore be used with confidence and still allow quick integrated plant simulations. (authors)

  19. Dynamic model of organic pollutant degradation in three dimensional packed bed electrode reactor.

    Science.gov (United States)

    Pang, Tianting; Wang, Yan; Yang, Hui; Wang, Tianlei; Cai, Wangfeng

    2018-04-21

    A dynamic model of semi-batch three-dimensional electrode reactor was established based on the limiting current density, Faraday's law, mass balance and a series of assumptions. Semi-batch experiments of phenol degradation were carried out in a three-dimensional electrode reactor packed with activated carbon under different conditions to verify the model. The factors such as the current density, the electrolyte concentration, the initial pH value, the flow rate of organic and the initial organic concentration were examined to know about the pollutant degradation in the three-dimensional electrode reactor. The various concentrations and logarithm of concentration of phenol with time were compared with the dynamic model. It was shown that the calculated data were in good agreement with experimental data in most cases. Copyright © 2018 Elsevier Ltd. All rights reserved.

  20. Gas-Liquid Two-Phase Flows Through Packed Bed Reactors in Microgravity

    Science.gov (United States)

    Motil, Brian J.; Balakotaiah, Vemuri

    2001-01-01

    The simultaneous flow of gas and liquid through a fixed bed of particles occurs in many unit operations of interest to the designers of space-based as well as terrestrial equipment. Examples include separation columns, gas-liquid reactors, humidification, drying, extraction, and leaching. These operations are critical to a wide variety of industries such as petroleum, pharmaceutical, mining, biological, and chemical. NASA recognizes that similar operations will need to be performed in space and on planetary bodies such as Mars if we are to achieve our goals of human exploration and the development of space. The goal of this research is to understand how to apply our current understanding of two-phase fluid flow through fixed-bed reactors to zero- or partial-gravity environments. Previous experiments by NASA have shown that reactors designed to work on Earth do not necessarily function in a similar manner in space. Two experiments, the Water Processor Assembly and the Volatile Removal Assembly have encountered difficulties in predicting and controlling the distribution of the phases (a crucial element in the operation of this type of reactor) as well as the overall pressure drop.

  1. Development of packed bed membrane reactor for the oxidative dehydrogenation of propane

    NARCIS (Netherlands)

    Kotanjac, Zeljko

    2009-01-01

    In this research, a reactor concept for the oxidative dehydrogenation of propane was studied. First a literature survey was performed, to investigate which are the best catalyst systems and best operating conditions that result in the largest propylene yield. In the kinetic study of ODHP over a

  2. Microscale packed bed reactor for controlled hydrogen peroxide decomposition as a fuel cell oxidant aboard unmanned undersea vehicles

    Energy Technology Data Exchange (ETDEWEB)

    Lennon, E.; Ocampo, M.; Besser, R.S. [Department of Chemical Engineering and Materials Science, Stevens Institute of Technology, Castle Point on Hudson, Hoboken, NJ 07030 (United States); Burke, A.A. [Naval Undersea Warfare Center, Newport, RI 02841 (United States)

    2010-01-01

    The multiphase catalytic decomposition of hydrogen peroxide into water and oxygen is notoriously susceptible to thermal runaway (heat of reaction: -98 kJ mol{sup -1}). The high surface area to volume ratio (S/V) in a microscale packed bed (MPB) reactor (radius 0.5 mm) was investigated for reducing the risk of thermal runaway during hydrogen peroxide decomposition to oxygen intended as a fuel cell oxidant aboard an unmanned undersea vehicle (UUV). A microscale reactor channel with a S/V of {proportional_to}2 x 10{sup 3} m{sup 2} m{sup -3} simulated under convective cooling generated a significant heat rise (T rise {proportional_to} 100 K), whereas a microreactor with a higher S/V ({proportional_to}200 x 10{sup 3} m{sup 2} m{sup -3}) achieved thermal control (T rise < 10 K) over the simulated reaction zone. Although thermal management was successfully accomplished using the higher S/V, experimental conversions of hydrogen peroxide to oxygen (5-18%) measured from the outlet were lower than simulated conversions (38-63%). Simulation assumptions, such as homogeneously dispersed flow and perfect catalyst interaction among other factors, contributed to the discrepancies between the simulated and experimental degrees of peroxide conversion to oxygen. Even though thermal control of the MPB was achieved, this work indicates that mass transfer limitations are a factor in the MPB reactor during a multiphase reaction, like decomposition of hydrogen peroxide to oxygen and water, and suggests means to overcome them even on the microscale level. (author)

  3. CONTINUOUS PRODUCTION OF ETHANOL IN PACKED BED-BIOREACTORS WITH IMMOBILIZED YEAST CELLS ON LIGNOCELLULOSIC WASTE

    Directory of Open Access Journals (Sweden)

    LINA MARÍA AGUDELO ESCOBAR

    2012-01-01

    Full Text Available Los procesos continuos con células inmovilizadas son una alternativa para mejorar la eficiencia y el rendimiento de las fermentaciones alcohólicas. Recientemente, se han comenzado a evaluar materias primas derivadas de residuos agroindustriales y su aplicación como soportes promisorios para la inmovilización celular. En este trabajo se evaluó la producción continua de etanol en reactores de lecho empacado con células de levadura inmovilizadas en residuos lignocelulósicos de viruta, bagazo de caña, capacho y tusa de maíz. Se empleó glucosa como fuente de carbono para establecer las condiciones de referencia y se realizaron las fermentaciones con sacarosa comercial. Además, se evaluó como sustrato alternativo el jarabe glucosado obtenido de la harina de yuca. Las experimentaciones fueron realizadas a nivel de laboratorio en reactores de columna de 250 mL. El bagazo de caña fue el material en el que se inmovilizó mayor cantidad de células. Se obtuvo un valor de 0,047 g de Biomasa/g de soporte (gX/gC. Para la fermentación realizada con glucosa, la productividad alcanzada fue de 13,33 ± 1,5 g/L h. Un valor similar, 13,00 ± 0,02 g/L h fue alcanzado para la productividad de la fermentación con sacarosa. En las fermentaciones realizadas con jarabe glucosado, se obtuvo mayor cantidad de etanol en el proceso que empleó tusa como soporte. Se produjeron 31,99 ± 1,93 g/L de etanol y se alcanzó una productividad de 10,66 ± 0,64 g/L h. Los resultados obtenidos han permitido establecer el potencial que tienen estos residuos lignocelulósicos como soportes en la inmovilización celular para la producción en continuo de etanol, y la posibilidad de emplear el jarabe glucosado como sustrato alternativo.

  4. The influence of TiO2 and aeration on the kinetics of electrochemical oxidation of phenol in packed bed reactor

    International Nuclear Information System (INIS)

    Wang Lizhang; Zhao Yuemin; Fu Jianfeng

    2008-01-01

    The electrochemical oxidation of phenolic wastewater in a lab-scale reactor, packed into granular activated carbon (GAC) with Ti/SnO 2 anodes and stainless steel cathodes, was interpreted in this study. GAC saturated rapidly if it was only used as sorbent, but application of suitable electric energy for the system simultaneously could recover the adsorption ability of GAC and maintain the continuous running effectively. The titanium dioxide (TiO 2 ) as catalyst and airflow were also applied to the electrochemical reactor to examine the enhancement for phenol oxidation process. Results revealed that the electrochemical degradation of phenol could be reasonably described by first-order kinetics. In addition, it was illustrated that acid region, increased voltage, more dosage of TiO 2 and higher aeration intensity were all beneficial parameters for phenol oxidation rates. By inspecting the relationship between the rate constants (k) and influencing factors, respectively, an overall kinetic model for phenol oxidation was proposed. The kinetics obtained from the experiments under corresponding electrochemical conditions could provide an accurate estimation of phenol concentration effluent and better design of the packed bed reactor

  5. The influence of TiO{sub 2} and aeration on the kinetics of electrochemical oxidation of phenol in packed bed reactor

    Energy Technology Data Exchange (ETDEWEB)

    Wang Lizhang [College of Environment and Spatial Informatics, China University of Mining and Technology, South Jiefang Road, Quanshan District, Xuzhou City, Jiangsu 221008 (China)], E-mail: wlzh0731@126.com; Zhao Yuemin [School of Chemical Engineering and Technology, China University of Mining and Technology, South Jiefang Road, Quanshan District, Xuzhou City, Jiangsu 221008 (China)], E-mail: ymzhao@cumt.edu.cn; Fu Jianfeng [Department of Environmental Engineering, Southeast University, Nanjing City, Jiangsu 210096 (China)

    2008-12-30

    The electrochemical oxidation of phenolic wastewater in a lab-scale reactor, packed into granular activated carbon (GAC) with Ti/SnO{sub 2} anodes and stainless steel cathodes, was interpreted in this study. GAC saturated rapidly if it was only used as sorbent, but application of suitable electric energy for the system simultaneously could recover the adsorption ability of GAC and maintain the continuous running effectively. The titanium dioxide (TiO{sub 2}) as catalyst and airflow were also applied to the electrochemical reactor to examine the enhancement for phenol oxidation process. Results revealed that the electrochemical degradation of phenol could be reasonably described by first-order kinetics. In addition, it was illustrated that acid region, increased voltage, more dosage of TiO{sub 2} and higher aeration intensity were all beneficial parameters for phenol oxidation rates. By inspecting the relationship between the rate constants (k) and influencing factors, respectively, an overall kinetic model for phenol oxidation was proposed. The kinetics obtained from the experiments under corresponding electrochemical conditions could provide an accurate estimation of phenol concentration effluent and better design of the packed bed reactor.

  6. Modeling and optimization of sunflower oil methanolysis over quicklime bits in a packed bed tubular reactor using the response surface methodology

    International Nuclear Information System (INIS)

    Miladinović, Marija R.; Stamenković, Olivera S.; Banković, Predrag T.; Milutinović-Nikolić, Aleksandra D.; Jovanović, Dušan M.; Veljković, Vlada B.

    2016-01-01

    Highlights: • Sunflower oil methanolysis in a continuous packed bed reactor was optimized. • Thermally-activated, low-cost quicklime bits were used as a catalyst. • Process was optimized by 3"3 full factorial design and Box-Behnken design. • Box-Behnken design is recommended for optimizing biodiesel production processes. • FAME content in the ester phase obtained under the optimum conditions was >98%. - Abstract: The effect of the residence time (i.e. liquid flow rate through the reactor), methanol-to-oil molar ratio and reaction temperature on the fatty acid methyl esters (FAMEs) content at the output of a continuous packed bed tubular reactor was modeled by the response surface methodology (RSM) combined with the 3"3 full factorial design (FFD) with replication or the Box-Behnken design (BBD) with five center points. The methanolysis of sunflower oil was carried out at the residence time of 1.0, 1.5 and 2.0 h, the methanol-to-oil molar ratios of 6:1, 12:1 and 18:1 and the reaction temperature of 40, 50 and 60 °C under the atmospheric pressure. Based on the used experimental designs, the model equations containing only linear and two-factor interaction terms were developed for predicting the FAME content, which were validated through the use of the unseen data. Applying the analysis of variance (ANOVA), all three factors were shown to have a significant influence on the FAME content. Acceptable statistical predictability and accuracy resulted from both designs since the values of the coefficient of determination were close to unity while the values of the mean relative percentage deviation were relatively low (<±10%). In addition, both designs predicted the maximum FAME content of above 99%, which agreed closely with the actual FAME content (98.8%). The same optimal reaction temperature (60 °C) and residence time (2.0 h) were determined by both designs while the BBD model suggested a slightly lower methanol-to-oil molar ratio (12.2:1) than the 3"3 FFD

  7. Effect of oxygen on ethanol fermentation in packed-bed tapered-column reactor

    Energy Technology Data Exchange (ETDEWEB)

    Hamamci, H.; Ryu, D.D.Y.

    1988-07-01

    In ethanol production with immobilized yeast a major problem is the provision of nutrients to these highly concentrated cells. O/sub 2/ being one of the nutrients of utmost importance to yeast cells, was fed into a column packed with beads with a cell loading of more than 40 g/l. Since addition of large volume of air or O/sub 2/ to a cylindrical column reactor would aggravate the problems of pressure build up and channelling caused by the evolving CO/sub 2/ gas, a tapered-column reactor and pulsed flow of oxygen gas was used. The supplement of O/sub 2/ gas to the tapered column increased the productivity from 21.1 g ethanol x (l gel x h)/sup -1/ to 26.7 g x (l gelxh)/sup -1/, when the ethanol concentration at the outlet was about 80 g/l. The yield coefficient of ethanol was also increased from 0.41 g ethanol/g glucose to 0.43 after O/sub 2/ supplement was started. The effects of frequency and duration of O/sub 2/ supplement were also determined.

  8. Bioconversion of D-galactose to D-tagatose: continuous packed bed reaction with an immobilized thermostable L-arabinose isomerase and efficient purification by selective microbial degradation.

    Science.gov (United States)

    Liang, Min; Chen, Min; Liu, Xinying; Zhai, Yafei; Liu, Xian-wei; Zhang, Houcheng; Xiao, Min; Wang, Peng

    2012-02-01

    The continuous enzymatic conversion of D-galactose to D-tagatose with an immobilized thermostable L-arabinose isomerase in packed-bed reactor and a novel method for D-tagatose purification were studied. L-arabinose isomerase from Thermoanaerobacter mathranii (TMAI) was recombinantly overexpressed and immobilized in calcium alginate. The effects of pH and temperature on D-tagatose production reaction catalyzed by free and immobilized TMAI were investigated. The optimal condition for free enzyme was pH 8.0, 60°C, 5 mM MnCl(2). However, that for immobilized enzyme was pH 7.5, 75°C, 5 mM MnCl(2). In addition, the catalytic activity of immobilized enzyme at high temperature and low pH was significantly improved compared with free enzyme. The optimum reaction yield with immobilized TMAI increased by four percentage points to 43.9% compared with that of free TMAI. The highest productivity of 10 g/L h was achieved with the yield of 23.3%. Continuous production was performed at 70°C; after 168 h, the reaction yield was still above 30%. The resultant syrup was then incubated with Saccharomyces cerevisiae L1 cells. The selective degradation of D-galactose was achieved, obtaining D-tagatose with the purity above 95%. The established production and separation methods further potentiate the industrial production of D-tagatose via bioconversion and biopurification processes.

  9. Performance of an enzymatic packed bed reactor running on babassu oil to yield fatty ethyl esters (FAEE in a solvent-free system

    Directory of Open Access Journals (Sweden)

    Aline Simões

    2015-06-01

    Full Text Available The transesterification reaction of babassu oil with ethanol mediated by Burkholderia cepacia lipase immobilized on SiO2-PVA composite was assessed in a packed bed reactor running in the continuous mode. Experiments were performed in a solvent-free system at 50 °C. The performance of the reactor (14 mm ×210 mm was evaluated using babassu oil and ethanol at two molar ratios of 1:7 and 1:12, respectively, and operational limits in terms of substrate flow rate were determined. The system’s performance was quantified for different flow rates corresponding to space times between 7 and 13 h. Under each condition, the impact of the space time on the ethyl esters formation, the transesterification yield and productivity were determined. The oil to ethanol molar ratio was found as a critical parameter in the conversion of babassu oil into the correspondent ethyl esters. The highest transesterification yield of 96.0 ± 0.9% and productivity of 41.1 ± 1.6 mgester gcatalyst-1h-1 were achieved at the oil to ethanol molar ratio of 1:12 and for space times equal or higher than 11 h. Moreover, the immobilized lipase was found stable with respect to its catalytic characteristics, exhibiting a half-life of 32 d.

  10. Packed-Bed Reactor Study of NETL Sample 196c for the Removal of Carbon Dioxide from Simulated Flue Gas Mixture

    Energy Technology Data Exchange (ETDEWEB)

    Hoffman, James S.; Hammache, Sonia; Gray, McMahan L.; Fauth Daniel J.; Pennline, Henry W.

    2012-04-24

    An amine-based solid sorbent process to remove CO2 from flue gas has been investigated. The sorbent consists of polyethylenimine (PEI) immobilized onto silica (SiO2) support. Experiments were conducted in a packed-bed reactor and exit gas composition was monitored using mass spectrometry. The effects of feed gas composition (CO2 and H2O), temperature, and simulated steam regeneration were examined for both the silica support as well as the PEI-based sorbent. The artifact of the empty reactor was also quantified. Sorbent CO2 capacity loading was compared to thermogravimetric (TGA) results to further characterize adsorption isotherms and better define CO2 working capacity. Sorbent stability was monitored by periodically repeating baseline conditions throughout the parametric testing and replacing with fresh sorbent as needed. The concept of the Basic Immobilized Amine Sorbent (BIAS) Process using this sorbent within a system where sorbent continuously flows between the absorber and regenerator was introduced. The basic tenet is to manipulate or control the level of moisture on the sorbent as it travels around the sorbent circulation path between absorption and regeneration stages to minimize its effect on regeneration heat duty.

  11. PRODUCTION OF MEDIUM-CHAIN ACYLGLYCEROLS BY LIPASE ESTERIFICATION IN PACKED BED REACTOR: PROCESS OPTIMIZATION BY RESPONSE SURFACE METHODOLOGY

    Directory of Open Access Journals (Sweden)

    ZANARIAH MOHD DOM

    2014-06-01

    Full Text Available Medium-chain acylglycerols (or glycerides are formed of mono-, di- and triacylglycerol classes. In this study, an alternative method to produce MCA from esterifying palm oil fatty acid distillate (PFAD with the presence of oil palm mesocarp lipase (OPML which is a plant-sourced lipase and PFAD is also cheap by-product is developed in a packed bed reactor. The production of medium-chain acylglycerols (MCA by lipase-catalysed esterification of palm oil fatty acid distillate with glycerol are optimize in order to determine the factors that have significant effects on the reaction condition and high yield of MCA. Response surface methodology (RSM was applied to optimize the reaction conditions. The reaction conditions, namely, the reaction time (30-240 min, enzyme load (0.5-1.5 kg, silica gel load (0.2-1.0 kg, and solvent amount (200-600 vol/wt. Reaction time, enzyme loading and solvent amount strongly effect MCA synthesis (p0.05 influence on MCA yield. Best-fitting models were successfully established for MCA yield (R 2 =0.9133. The optimum MCA yield were 75% from the predicted value and 75.4% from the experimental data for 6 kg enzyme loading, a reaction time of 135min and a solvent amount of 350 vol/wt at 65ºC reaction temperature. Verification of experimental results under optimized reaction conditions were conducted, and the results agreed well with the predicted range. Esterification products (mono-, di- and triacylglycerol from the PBR were identified using Thin Layer Chromatography method. The chromatograms showed the successful fractionation of esterified products in this alternative method of process esterification.

  12. Thermo-catalytic pyrolysis of waste polyethylene bottles in a packed bed reactor with different bed materials and catalysts

    International Nuclear Information System (INIS)

    Obeid, Farah; Zeaiter, Joseph; Al-Muhtaseb, Ala’a H.; Bouhadir, Kamal

    2014-01-01

    Highlights: • Thermo-catalytic pyrolysis of waste polyethylene bottles was investigated. • The highest yield of liquid (82%) was obtained over a cement powder bed. • Acidic catalysts narrowed the carbon chain length of the paraffins to C 10 –C 28 . • Combination of cement bed with HBeta catalyst gave the highest yield of liquid. • Significant yield of aromatics was obtained mainly naphthalene and D-limonene. - Abstract: Plastic waste is an increasing economic and environmental problem as such there is a great need to process this waste and reduce its environmental impact. In this work, the pyrolysis of high density polyethylene (HDPE) waste products was investigated using both thermal and catalytic cracking techniques. The experimental work was carried out using packed bed reactor operating under an inert atmosphere at 450 °C. Different reactor bed materials, including sand, cement and white clay were used to enhance the thermal cracking of HDPE. In addition, the catalytic effect of sodium hydroxide, HUSY and HBeta zeolite catalysts on the degradation of HDPE waste was also investigated. The reactor beds were found to significantly alter the yield as well as the product composition. Products such as paraffins (⩽C 44 ), olefins (⩽C 22 ), aromatics (⩽C 14 ) and alcohols (C 16 and C 17 ) were obtained at varying rates. The highest yield of liquid (82%) was obtained over a cement powder bed with a paraffin yield of 58%. The yield of paraffins and olefins followed separate paths, for paraffins it was found to increase in the order or Cement > White clay > Silica Sand, whereas for the olefins it was in the reverse order Silica Sand > White clay > Cement. The results obtained in this work exhibited a higher P/O ratio than expected, where the amount of generated paraffins was greater than 60% in most cases. Less olefin was generated as a consequence. This indicates that the product generated is more suited to be used as a fuel rather than as a chemical

  13. Calcium oxide/carbon dioxide reactivity in a packed bed reactor of a chemical heat pump for high-temperature gas reactors

    International Nuclear Information System (INIS)

    Kato, Yukitaka; Yamada, Mitsuteru; Kanie, Toshihiro; Yoshizawa, Yoshio

    2001-01-01

    The thermal performance of a chemical heat pump that uses a calcium oxide/carbon dioxide reaction system was discussed as a heat storage system for utilizing heat output from high temperature gas reactors (HTGR). Calcium oxide/carbon dioxide reactivity for the heat pump was measured using a packed bed reactor containing 1.0 kg of reactant. The reactor was capable of storing heat at 900 deg. C by decarbonation of calcium carbonate and generating up to 997 deg. C by carbonation of calcium oxide. The amount of stored heat in the reactor was 800-900 kJ kg -1 . The output temperature of the reactor could be controlled by regulating the carbonation pressure. The thermal storage performance of the reactor was superior to that of conventional sensible heat storage systems. A heat pump using this CaO/CO 2 reactor is expected to contribute to thermal load leveling and to realize highly efficient utilization of HTGR output due to the high heat storage density and high-quality temperature output of the heat pump

  14. Immobilisation of laccase on Eupergit supports and its application for the removal of endocrine disrupting chemicals in a packed-bed reactor.

    Science.gov (United States)

    Lloret, L; Hollmann, F; Eibes, G; Feijoo, G; Moreira, M T; Lema, J M

    2012-06-01

    Laccase from Myceliophthora thermophila was covalently immobilised on Eupergit C and Eupergit C 250L yielding specific activities of up to 17 and 80 U/g, respectively. Due to its superior activity, Eupergit C 250L was chosen for further research. The somewhat lower catalytic efficiency (based on the ratio between the turnover number and the Michaelis constant, k(cat)/K(M)) of the immobilised enzyme in comparison with that of the free enzyme was balanced by its increased stability and broader operational window related to temperature and pH. The feasibility of the immobilised laccase was tested by using a packed bed reactor (PBR) operating in consecutive cycles for the removal of Acid Green 27 dye as model substrate. High degrees of elimination were achieved (88, 79, 69 and 57% in 4 consecutive cycles), while the levels of adsorption on the support varied from 18 to 6%, proving that dye removal took place mainly due to the action of the enzyme. Finally, a continuous PBR with the solid biocatalyst was applied for the treatment of a solution containing the following endocrine disrupting chemicals: estrone (E1), 17β-estradiol (E2) and 17α-ethinylestradiol (EE2). At steady-state operation, E1 was degraded by 65% and E2 and EE2 were removed up to 80% and only limited adsorption of these compounds on the support, between 12 and 22%, was detected. In addition, a 79% decrease in estrogenic activity was detected in the effluent of the enzymatic reactor while only 14% was attained by inactivated laccase.

  15. Experimental studies on the coolability of packed beds. Flooding of hot dry packed beds

    International Nuclear Information System (INIS)

    Leininger, S.; Kulenovic, R.; Laurien, E.

    2013-01-01

    In case of a severe accident in a nuclear power plant meltdown of the reactor core can occur and form a packed bed in the lower plenum of the reactor pressure vessel (RPV) after solidification due to contact with water. The removal of after-heat and the long-term coolability is of essential interest. The efficient injection of cooling water into the packed bed has to be assured without endangering the structural integrity of the reactor pressure vessel. The experiments performed aimed to study the dry-out and the quenching (flooding) of hot dry packed beds. Two different inflow variants, bottom- and top-flooding including the variation of the starting temperature of the packed bed and the injection rate were studied. In case of bottom flooding the quenching time increases with increasing packed bed temperature and decreasing injection rate. In case of top flooding the flow pattern is more complex, in a first phase the water flows preferentially toward the RPV wall, the flow paths conduct the water downwards. The flow resistance of the packed bed increases with increasing bed temperatures. The quenching temperatures increase significantly above average.

  16. Evaluation of co-pyrolysis petrochemical wastewater sludge with lignite in a thermogravimetric analyzer and a packed-bed reactor: Pyrolysis characteristics, kinetics, and products analysis.

    Science.gov (United States)

    Mu, Lin; Chen, Jianbiao; Yao, Pikai; Zhou, Dapeng; Zhao, Liang; Yin, Hongchao

    2016-12-01

    Co-pyrolysis characteristics of petrochemical wastewater sludge and Huolinhe lignite were investigated using thermogravimetric analyzer and packed-bed reactor coupled with Fourier transform infrared spectrometer and gas chromatography. The pyrolysis characteristics of the blends at various sludge blending ratios were compared with those of the individual materials. Thermogravimetric experiments showed that the interactions between the blends were beneficial to generate more residues. In packed-bed reactor, synergetic effects promoted the release of gas products and left less liquid and solid products than those calculated by additive manner. Fourier transform infrared spectrometer analysis showed that main functional groups in chars gradually disappeared with pyrolysis temperatures increasing, and H 2 O, CH 4 , CO, and CO 2 appeared in volatiles during pyrolysis. Gas compositions analysis indicated that, the yields of H 2 and CO clearly increased as the pyrolysis temperature and sludge blending ratio increasing, while the changes of CH 4 and CO 2 yields were relatively complex. Copyright © 2016 Elsevier Ltd. All rights reserved.

  17. Understanding the performance of sulfate reducing bacteria based packed bed reactor by growth kinetics study and microbial profiling.

    Science.gov (United States)

    Dev, Subhabrata; Roy, Shantonu; Bhattacharya, Jayanta

    2016-07-15

    A novel marine waste extract (MWE) as alternative nitrogen source was explored for the growth of sulfate reducing bacteria (SRB). Variation of sulfate and nitrogen (MWE) showed that SRB growth follows an uncompetitive inhibition model. The maximum specific growth rates (μmax) of 0.085 and 0.124 h(-1) and inhibition constants (Ki) of 56 and 4.6 g/L were observed under optimized sulfate and MWE concentrations, respectively. The kinetic data shows that MWE improves the microbial growth by 27%. The packed bed bioreactor (PBR) under optimized sulfate and MWE regime showed sulfate removal efficiency of 62-66% and metals removal efficiency of 66-75% on using mine wastewater. The microbial community analysis using DGGE showed dominance of SRB (87-89%). The study indicated the optimum dosing of sulfate and cheap organic nitrogen to promote the growth of SRB over other bacteria. Copyright © 2016 Elsevier Ltd. All rights reserved.

  18. Biodegradation of 2,4,6-trichlorophenol in a packed-bed biofilm reactor equipped with an internal net draft tube riser for aeration and liquid circulation

    Energy Technology Data Exchange (ETDEWEB)

    Gomez-De Jesus, A.; Romano-Baez, F.J.; Leyva-Amezcua, L.; Juarez-Ramirez, C.; Ruiz-Ordaz, N. [Departamento de Ingenieria Bioquimica, Escuela Nacional de Ciencias Biologicas, IPN. Prol. Carpio y Plan de Ayala, Colonia Santo Tomas, s/n. CP 11340, Mexico, D.F. (Mexico); Galindez-Mayer, J. [Departamento de Ingenieria Bioquimica, Escuela Nacional de Ciencias Biologicas, IPN. Prol. Carpio y Plan de Ayala, Colonia Santo Tomas, s/n. CP 11340, Mexico, D.F. (Mexico)], E-mail: cmayer@encb.ipn.mx

    2009-01-30

    For the aerobic biodegradation of the fungicide and defoliant 2,4,6-trichlorophenol (2,4,6-TCP), a bench-scale packed-bed bioreactor equipped with a net draft tube riser for liquid circulation and oxygenation (PB-ALR) was constructed. To obtain a high packed-bed volume relative to the whole bioreactor volume, a high A{sub D}/A{sub R} ratio was used. Reactor's downcomer was packed with a porous support of volcanic stone fragments. PB-ALR hydrodynamics and oxygen mass transfer behavior was evaluated and compared to the observed behavior of the unpacked reactor operating as an internal airlift reactor (ALR). Overall gas holdup values {epsilon}{sub G}, and zonal oxygen mass transfer coefficients determined at various airflow rates in the PB-ALR, were higher than those obtained with the ALR. When comparing mixing time values obtained in both cases, a slight increment in mixing time was observed when reactor was operated as a PB-ALR. By using a mixed microbial community, the biofilm reactor was used to evaluate the aerobic biodegradation of 2,4,6-TCP. Three bacterial strains identified as Burkholderia sp., Burkholderia kururiensis and Stenotrophomonas sp. constituted the microbial consortium able to cometabolically degrade the 2,4,6-TCP, using phenol as primary substrate. This consortium removed 100% of phenol and near 99% of 2,4,6-TCP. Mineralization and dehalogenation of 2,4,6-TCP was evidenced by high COD removal efficiencies ({approx}95%), and by the stoichiometric release of chloride ions from the halogenated compound ({approx}80%). Finally, it was observed that the microbial consortium was also capable to metabolize 2,4,6-TCP without phenol as primary substrate, with high removal efficiencies (near 100% for 2,4,6-TCP, 92% for COD and 88% for chloride ions)

  19. Production of structured lipids by acidolysis of an EPA-enriched fish oil and caprylic acid in a packed bed reactor: analysis of three different operation modes.

    Science.gov (United States)

    González Moreno, P A; Robles Medina, A; Camacho Rubio, F; Camacho Páez, B; Molina Grima, E

    2004-01-01

    Structured triacylglycerols (ST) enriched in eicosapentaenoic acid (EPA) in position 2 of the triacylglycerol (TAG) backbone were synthesized by acidolysis of a commercially available EPA-rich oil (EPAX4510, 40% EPA) and caprylic acid (CA), catalyzed by the 1,3-specific immobilized lipase Lipozyme IM. The reaction was carried out in a packed bed reactor (PBR) operating in two ways: (1) by recirculating the reaction mixture from the exit of the bed to the substrate reservoir (discontinuous mode) and (2) in continuous mode, directing the product mixture leaving the PBR to a product reservoir. By operating in these two ways and using a simple kinetic model, representative values for the apparent kinetic constants (kX) for each fatty acid (native, Li or odd, M) were obtained. The kinetic model assumes that the rate of incorporation of a fatty acid into TAG per amount of enzyme, rX (mole/(h g lipase)) is proportional to the extent of the deviation from the equilibrium for each fatty acid (i.e., the difference of concentration between the fatty acid in the triacylglycerol and the concentration of the same fatty acid in the triacylglycerol once the equilibrium of the acidolysis reaction is reached). The model allows comparing the two operating modes through the processing intensity, defined as mLt/(V[TG]0) and mL/(q[TG]0), for the discontinuous and continuous operation modes, respectively. In discontinuous mode, ST with 59.5% CA and 9.6% EPA were obtained. In contrast, a ST with 51% CA and 19.6% EPA were obtained when using the continuous operation mode. To enhance the CA incorporation when operating in continuous mode, a two-step acidolysis reaction was performed (third operation mode). This continuous two-step process yields a ST with a 64% CA and a 15% EPA. Finally, after purifying the above ST in a preparative silica gel column, impregnated with boric acid, a ST with 66.9% CA and 19.6% EPA was obtained. The analysis by reverse phase and Ag+ liquid chromatography of

  20. Continuous cadmium removal from aqueous solutions by seaweed in a packed-bed column under consecutive sorption-desorption cycles

    International Nuclear Information System (INIS)

    Jafari, Seyed Ali; Jamali, Abbas

    2016-01-01

    Packed-bed column process efficiency for cadmium adsorption from aqueous solution was investigated under different bed heights (2.6 to 7.5 cm) and feed flow rates (15 to 30 ml min -1 ). The column was filled with brown seaweed, Sargassum angustifolium. Three simplified models, including Bed Depth Service Time, Thomas, and Yoon- Nelson were employed for describing the experimental breakthrough curves as well as achieving design parameters. Bed lifetime was also evaluated in several consecutive sorption-desorption cycles. Cadmium concentration of 0.005mg l−1, as a standard limit for potable water, was considered as the breakthrough concentration. The maximum column performance was achieved 81% at 7.5 cm bed length and flow rate of 15 ml min -1 . Indeed, increasing the bed height increased the sorption performance and service time, while increasing the feed flow rate had a negative effect. Maximum sorption capacity value remained almost constant by the bed height changes; however, increase in the feed flow rate slightly decreased it. The modeling results revealed that the Yoon-Nelson model was more accurate than Thomas for describing the experimental breakthrough data, especially at low flow rates. Column service time predictions were surprisingly achieved using the Bed Depth Service Time model even at extrapolations. 20% reduction in column adsorption efficiency was observed at the end of four consecutive sorption-desorption cycles; however, desorption efficiencies were achieved more than 99% in each cycle.

  1. Continuous cadmium removal from aqueous solutions by seaweed in a packed-bed column under consecutive sorption-desorption cycles

    Energy Technology Data Exchange (ETDEWEB)

    Jafari, Seyed Ali; Jamali, Abbas [Persian Gulf Research Institute, Persian Gulf University, 75169, Bushehr (Iran, Islamic Republic of)

    2016-04-15

    Packed-bed column process efficiency for cadmium adsorption from aqueous solution was investigated under different bed heights (2.6 to 7.5 cm) and feed flow rates (15 to 30 ml min{sup -1}). The column was filled with brown seaweed, Sargassum angustifolium. Three simplified models, including Bed Depth Service Time, Thomas, and Yoon- Nelson were employed for describing the experimental breakthrough curves as well as achieving design parameters. Bed lifetime was also evaluated in several consecutive sorption-desorption cycles. Cadmium concentration of 0.005mg l−1, as a standard limit for potable water, was considered as the breakthrough concentration. The maximum column performance was achieved 81% at 7.5 cm bed length and flow rate of 15 ml min{sup -1}. Indeed, increasing the bed height increased the sorption performance and service time, while increasing the feed flow rate had a negative effect. Maximum sorption capacity value remained almost constant by the bed height changes; however, increase in the feed flow rate slightly decreased it. The modeling results revealed that the Yoon-Nelson model was more accurate than Thomas for describing the experimental breakthrough data, especially at low flow rates. Column service time predictions were surprisingly achieved using the Bed Depth Service Time model even at extrapolations. 20% reduction in column adsorption efficiency was observed at the end of four consecutive sorption-desorption cycles; however, desorption efficiencies were achieved more than 99% in each cycle.

  2. A fast linear predictive adaptive model of packed bed coupled with UASB reactor treating onion waste to produce biofuel.

    Science.gov (United States)

    Milquez-Sanabria, Harvey; Blanco-Cocom, Luis; Alzate-Gaviria, Liliana

    2016-10-03

    Agro-industrial wastes are an energy source for different industries. However, its application has not reached small industries. Previous and current research activities performed on the acidogenic phase of two-phase anaerobic digestion processes deal particularly with process optimization of the acid-phase reactors operating with a wide variety of substrates, both soluble and complex in nature. Mathematical models for anaerobic digestion have been developed to understand and improve the efficient operation of the process. At present, lineal models with the advantages of requiring less data, predicting future behavior and updating when a new set of data becomes available have been developed. The aim of this research was to contribute to the reduction of organic solid waste, generate biogas and develop a simple but accurate mathematical model to predict the behavior of the UASB reactor. The system was maintained separate for 14 days during which hydrolytic and acetogenic bacteria broke down onion waste, produced and accumulated volatile fatty acids. On this day, two reactors were coupled and the system continued for 16 days more. The biogas and methane yields and volatile solid reduction were 0.6 ± 0.05 m 3 (kg VS removed ) -1 , 0.43 ± 0.06 m 3 (kg VS removed ) -1 and 83.5 ± 9.8 %, respectively. The model application showed a good prediction of all process parameters defined; maximum error between experimental and predicted value was 1.84 % for alkalinity profile. A linear predictive adaptive model for anaerobic digestion of onion waste in a two-stage process was determined under batch-fed condition. Organic load rate (OLR) was maintained constant for the entire operation, modifying effluent hydrolysis reactor feed to UASB reactor. This condition avoids intoxication of UASB reactor and also limits external buffer addition.

  3. Long-term studies in COD elimination and nitrification in an overcongested packed-bed reactor (biofilter); Langzeituntersuchungen zur CSB-Elimination und Nitrifikation in einem ueberstauten Festbettreaktor (Biofilter)

    Energy Technology Data Exchange (ETDEWEB)

    Engelhart, M.; Dichtl, N. [Technische Univ. Braunschweig (Germany). Inst. fuer Siedlungswasserwirtschaft

    1999-07-01

    On a semi-technical scale, two process combinations were tested for their suitability for COD elimination and nitrification in combination with an overcongested packed-bed reactor (biofilter). (orig.) [German] Im halbtechnischen Massstab wurden zwei Verfahrenskombinationen unter Einbeziehung eines ueberstauten Festbettreaktors (Biofilter) auf ihre Tauglichkeit zur CSB-Elimination und Nitrifikation untersucht. (orig.)

  4. Upflow anaerobic sludge blanket-hollow centered packed bed (UASB-HCPB) reactor for thermophilic palm oil mill effluent (POME) treatment

    International Nuclear Information System (INIS)

    Poh, P.E.; Chong, M.F.

    2014-01-01

    Upflow anaerobic sludge blanket-hollow centered packed bed (UASB-HCPB) reactor was developed with the aim to minimize operational problems in the anaerobic treatment of Palm Oil Mill Effluent (POME) under thermophilic conditions. The performance of UASB-HCPB reactor on POME treatment was investigated at 55 °C. Subsequent to start-up, the performance of the UASB-HCPB reactor was evaluated in terms of i) effect of hydraulic retention time (HRT); ii) effect of organic loading rate (OLR); and iii) effect of mixed liquor volatile suspended solid (MLVSS) concentration on thermophilic POME treatment. Start-up up of the UASB-HCPB reactor was completed in 36 days, removing 88% COD and 90% BOD respectively at an OLR of 28.12 g L −1  d −1 , producing biogas with 52% of methane. Results from the performance study of the UASB-HCPB reactor on thermophilic POME treatment indicated that HRT of 2 days, OLR of 27.65 g L −1  d −1 and MLVSS concentration of 14.7 g L −1 was required to remove 90% of COD and BOD, 80% of suspended solid and at the same time produce 60% of methane. - Highlights: • UASB-HCPB was proposed for POME treatment under thermophilic conditions. • Start-up up of the UASB-HCPB reactor was completed in 36 days. • 88% COD and 90% BOD were removed at an OLR of 28.12 g COD/L.day during start-up. • HRT of 2 days and OLR of 27.65 g COD/L.day was required to produce 60% methane. • Methanosarcina sp. forms the majority of microbial population in the UASB section

  5. An in situ spatially resolved analytical technique to simultaneously probe gas phase reactions and temperature within the packed bed of a plug flow reactor.

    Science.gov (United States)

    Touitou, Jamal; Burch, Robbie; Hardacre, Christopher; McManus, Colin; Morgan, Kevin; Sá, Jacinto; Goguet, Alexandre

    2013-05-21

    This paper reports the detailed description and validation of a fully automated, computer controlled analytical method to spatially probe the gas composition and thermal characteristics in packed bed systems. As an exemplar, we have examined a heterogeneously catalysed gas phase reaction within the bed of a powdered oxide supported metal catalyst. The design of the gas sampling and the temperature recording systems are disclosed. A stationary capillary with holes drilled in its wall and a moveable reactor coupled with a mass spectrometer are used to enable sampling and analysis. This method has been designed to limit the invasiveness of the probe on the reactor by using the smallest combination of thermocouple and capillary which can be employed practically. An 80 μm (O.D.) thermocouple has been inserted in a 250 μm (O.D.) capillary. The thermocouple is aligned with the sampling holes to enable both the gas composition and temperature profiles to be simultaneously measured at equivalent spatially resolved positions. This analysis technique has been validated by studying CO oxidation over a 1% Pt/Al2O3 catalyst and the spatial resolution profiles of chemical species concentrations and temperature as a function of the axial position within the catalyst bed are reported.

  6. Development of an ultrahigh-temperature process for the enzymatic hydrolysis of lactose. IV. Immobilization of two thermostable beta-glycosidases and optimization of a packed-bed reactor for lactose conversion.

    Science.gov (United States)

    Petzelbauer, Inge; Kuhn, Bernhard; Splechtna, Barbara; Kulbe, Klaus D; Nidetzky, Bernd

    2002-03-20

    Recombinant hyperthermostable beta-glycosidases from the archaea Sulfolobus solfataricus (Ss beta Gly) and Pyrococcus furiosus (CelB) were covalently attached onto the insoluble carriers chitosan, controlled pore glass (CPG), and Eupergit C. For each enzyme/carrier pair, the protein-binding capacity, the immobilization yield, the pH profiles for activity and stability, the activity/temperature profile, and the kinetic constants for lactose hydrolysis at 70 degrees C were determined. Eupergit C was best among the carriers in regard to retention of native-like activity and stability of Ss beta Gly and CelB over the pH range 3.0-7.5. Its protein binding capacity of approximately 0.003 (on a mass basis) was one-third times that of CPG, while immobilization yields were typically 80% in each case. Activation energies for lactose conversion by the immobilized enzymes at pH 5.5 were in the range 50-60 kJ/mol. This is compared to values of approximately 75 kJ/mol for the free enzymes. Immobilization expands the useful pH range for CelB and Ss beta Gly by approximately 1.5 pH units toward pH 3.5 and pH 4.5, respectively. A packed-bed enzyme reactor was developed for the continuous conversion of lactose in different media, including whey and milk, and operated over extended reaction times of up to 14 days. The productivities of the Eupergit C-immobilized enzyme reactor were determined at dilution rates between 1 and 12 h(-1), and using 45 and 170 g/L initial lactose. Results of kinetic modeling for the same reactor, assuming plug flow and steady state, suggest the presence of mass-transfer limitation of the reaction rate under the conditions used. Formation of galacto-oligosaccharides in the continuous packed-bed reactor and in the batch reactor using free enzyme was closely similar in regard to yield and individual saccharide components produced. Copyright 2002 John Wiley & Sons, Inc. Biotechnol Bioeng 77: 619-631, 2002; DOI 10.1002/bit.10110

  7. Supported Photocatalyst for Removal of Emerging Contaminants from Wastewater in a Continuous Packed-Bed Photoreactor Configuration

    OpenAIRE

    Borges, Mª; García, Dulce; Hernández, Tania; Ruiz-Morales, Juan; Esparza, Pedro

    2015-01-01

    Water pollution from emerging contaminants (ECs) or emerging pollutants is an important environmental problem. Heterogeneous photocatalytic treatment, as advanced oxidation treatment of wastewater effluents, has been proposed to solve this problem. In this paper, a heterogeneous photocatalytic process was studied for emergent contaminants removal using paracetamol as a model contaminant molecule. TiO2 photocatalytic activity was evaluated using two photocatalytic reactor configurations: Photo...

  8. Successive pretreatment and enzymatic saccharification of sugarcane bagasse in a packed bed flow-through column reactor aiming to support biorefineries.

    Science.gov (United States)

    Terán-Hilares, R; Reséndiz, A L; Martínez, R T; Silva, S S; Santos, J C

    2016-03-01

    A packed bed flow-through column reactor (PBFTCR) was used for pretreatment and subsequent enzymatic hydrolysis of sugarcane bagasse (SCB). Alkaline pretreatment was performed at 70 °C for 4h with fresh 0.3M NaOH solution or with liquor recycled from a previous pretreatment batch. Scheffersomyces stipitis NRRL-Y7124 was used for fermentation of sugars released after enzymatic hydrolysis (20 FPU g(-1) of dry SCB). The highest results for lignin removal were 61% and 52%, respectively, observed when using fresh NaOH or the first reuse of the liquor. About 50% of cellulosic and 57% of hemicellulosic fractions of pretreated SCBs were enzymatically hydrolyzed and the maximum ethanol production was 23.4 g L(-1) (ethanol yield of 0.4 gp gs(-1)), with near complete consumption of both pentoses and hexoses present in the hydrolysate during the fermentation. PBFTCR as a new alternative for SCB-biorefineries is presented, mainly considering its simple configuration and efficiency for operating with a high solid:liquid ratio. Copyright © 2015 Elsevier Ltd. All rights reserved.

  9. Acidolysis of terebinth fruit oil with palmitic and caprylic acids in a recirculating packed bed reactor: optimization using response surface methodology

    Energy Technology Data Exchange (ETDEWEB)

    Koçak, D.; Keskin, H.; Fadiloglu, S.; Gögüs, F.

    2016-07-01

    The acidolysis reaction of terebinth fruit oil with caprylic and palmitic acid has been investigated. The reaction was catalyzed by lipase (Lipozyme IM from Rhizomucormiehei) and carried out in recirculating packed bed reactor. The effects of reaction parameters have been analyzed using response surface methodology. Reaction time (3.5–6.5 h), enzyme load (10–20%), substrate flow rate (4–8 mL·min−1 ) and substrate mole ratios (Terebinth oil : Palmitic acid : Caprylic acid, 1:1.83:1.22–1:3.07:2.05) were evaluated. The optimum reaction conditions were 5.9 h reaction time, 10% enzyme load, 4 mL·min−1 substrate flow rate and 1:3.10:2.07 substrate mole ratio. The structured lipid obtained at these optimum conditions had 52.23% desired triacylglycerols and a lower caloric value than that of terebinth fruit oil. The melting characteristics and microstructure of the structured lipid were similar to those of commercial margarine fat extracts. The results showed that the structured lipid had the highest oxidative stability among the studied fats. (Author)

  10. Enzymatic production of biodiesel from waste cooking oil in a packed-bed reactor: an engineering approach to separation of hydrophilic impurities.

    Science.gov (United States)

    Hama, Shinji; Yoshida, Ayumi; Tamadani, Naoki; Noda, Hideo; Kondo, Akihiko

    2013-05-01

    An engineering approach was applied to an efficient biodiesel production from waste cooking oil. In this work, an enzymatic packed-bed reactor (PBR) was integrated with a glycerol-separating system and used successfully for methanolysis, yielding a methyl ester content of 94.3% and glycerol removal of 99.7%. In the glycerol-separating system with enhanced retention time, the effluent contained lesser amounts of glycerol and methanol than those in the unmodified system, suggesting its promising ability to remove hydrophilic impurities from the oil layer. The PBR system was also applied to oils with high acid values, in which fatty acids could be esterified and the large amount of water was extracted using the glycerol-separating system. The long-term operation demonstrated the high lipase stability affording less than 0.2% residual triglyceride in 22 batches. Therefore, the PBR system, which facilitates the separation of hydrophilic impurities, is applicable to the enzymatic biodiesel production from waste cooking oil. Copyright © 2012 Elsevier Ltd. All rights reserved.

  11. Pathways of 3-biofules (hydrogen, ethanol and methane) production from petrochemical industry wastewater via anaerobic packed bed baffled reactor inoculated with mixed culture bacteria

    International Nuclear Information System (INIS)

    Elreedy, Ahmed; Tawfik, Ahmed; Enitan, Abimbola; Kumari, Sheena; Bux, Faizal

    2016-01-01

    Highlights: • Bio-energy production from MEG contaminated wastewater via AnPBBR, was assessed. • Maximum concurrent H_2 and CH_4 production of 6.57 and 3.57 L/d were obtained. • Maximum ethanol generation of 237.13 mg/L was observed at a HRT of 9 h. • At OLRs up to 4 gCOD/L/d, MEG biodegradability of 71–98% was achieved. • AnPBBR economically achieved shorter payback period (6.25 y), compared to ABR. - Abstract: Simultaneous production of 3-biofuels (hydrogen, ethanol and methane) as by-products of the biodegradation of petrochemical wastewater containing MEG via anaerobic packed bed baffled reactor (AnPBBR), was extensively investigated. A four-chambered reactor supported by polyurethane sheets, was operated at a constant hydraulic retention time (HRT) of 36 h and different organic loading rates (OLRs) of 0.67, 1, 2 and 4 gCOD/L/d. The maximum specific H_2 and CH_4 production rates of 438.07 ± 43.02 and 237.80 ± 21.67 ml/L/d were respectively achieved at OLR of 4 gCOD/L/d. The residual bio-ethanol significantly increased from 57.15 ± 2.31 to 240.19 ± 34.69 mg/L at increasing the OLR from 0.67 to 4 gCOD/L/d, respectively. The maximum MEG biodegradability of 98% was attained at the lowest OLR. Compartment-wise profiles revealed that the maximum H_2 and ethanol production were achieved at HRT of 9 h (1st compartment), while the CH_4 production was peaked at HRTs of 27 and 36 h (last two compartments). Kinetic studies using Stover–Kincannon and completely stirred tank reactor (CSTR) in series models were successfully applied to the AnPBBR overall and compartment-to-compartment performance, respectively. The economic evaluation strongly revealed the potentials of using AnPBBR for simultaneous treatment and bio-energy production from petrochemical wastewater as compared to the classical anaerobic baffled reactor (ABR). Microbial analysis using Illumina MiSeq sequencing showed a diversity of bacterial community in AnPBBR. Proteobacteria (36

  12. Operational stability of naringinase PVA lens-shaped microparticles in batch stirred reactors and mini packed bed reactors-one step closer to industry.

    Science.gov (United States)

    Nunes, Mário A P; Rosa, M Emilia; Fernandes, Pedro C B; Ribeiro, Maria H L

    2014-07-01

    The immobilization of naringinase in PVA lens-shaped particles, a cheap and biocompatible hydrogel was shown to provide an effective biocatalyst for naringin hydrolysis, an appealing reaction in the food and pharmaceutical industries. The present work addresses the operational stability and scale-up of the bioconversion system, in various types of reactors, namely shaken microtiter plates (volume ⩽ 2 mL), batch stirred tank reactors (volume reactor (PBR, 6.8 mL). Consecutive batch runs were performed with the shaken/stirred vessels, with reproducible and encouraging results, related to operational stability. The PBR was used to establish the feasibility for continuous operation, running continuously for 54 days at 45°C. The biocatalyst activity remained constant for 40 days of continuous operation. The averaged specific productivity was 9.07 mmol h(-1) g enzyme(-1) and the half-life of 48 days. Copyright © 2014 Elsevier Ltd. All rights reserved.

  13. Continuous aerobic phenol degradation by defined mixed immobilized cultutre in packed bed reactors

    Czech Academy of Sciences Publication Activity Database

    Páca jr., J.; Páca, J.; Kostečková, A.; Stiborová, M.; Sobotka, Miroslav; Gerrard, A. M.; Soccol, C. R.

    2005-01-01

    Roč. 50, č. 4 (2005), s. 301-308 ISSN 0015-5632 R&D Projects: GA ČR GA104/03/0407 Institutional research plan: CEZ:AV0Z50200510 Keywords : phenol degradation * pseudomonas putida * commamonas testosteroni Subject RIV: EE - Microbiology, Virology Impact factor: 0.918, year: 2005

  14. Continuous biodegradation of sulfanilic acid in a multi-stage packed bed reactor

    International Nuclear Information System (INIS)

    Salazar-Huerta, A.; Velazquez-Garcia, A.; Cobos-Vasconcelos, D. de los.; Juarez-Ramirez, C.; Ruiz-Ordaz, N.; Galindez-Mayer, J.

    2009-01-01

    Sulfanilic acid SA is an aromatic amine derived from the azo-bond cleavage of several textile dyes. Recalcitrance and toxicity of this amine is high, and with frequency it could be found as an aquatic contaminant; thus biodegradation process for its removal are justified. Although the SA molecule contains carbon, nitrogen and sulphur, its C:N:S proportion is unbalanced for microbial growth in a biodegradation process; thus nutrient complementation should be necessary for its complete removal. (Author)

  15. MAPPING THE REGION OF INSTABILITY FOR ADIABATIC PACKED BED REACTORS USING A HOMOTOPY CONTINUATION METHOD

    Directory of Open Access Journals (Sweden)

    JUAN PABLO GUTIÉRREZ HERNANDEZ

    2010-01-01

    gas de síntesis, y la oxidación de SO2. Las ecuaciones son parametrizadas y resueltas de acuerdo a un método de continuación por homotopía. Los resultados demuestran que la concentración de inertes y la presión tienen marcada influencia sobre el tamaño de la región de inestabilidad.

  16. Photocatalytic Active Coatings for Lignin Degradation in a Continuous Packed Bed Reactor

    Directory of Open Access Journals (Sweden)

    Colin Awungacha Lekelefac

    2014-01-01

    Full Text Available The synthesis of immobilized catalyst on porous glass support material via the sol-gel route is reported. TiO2-P25-SiO2 + Pt, TiO2-P25-SiO2, TiOSO4_30.6 wt%, and ZnO + TiO2-P25-SiO2 catalysts were synthesized and a comparative study is done regarding morphology of coatings, degradation rates, reaction rates, dissolved carbon (DC, formation of peaks, and fluorescence of products formed from the photocatalytic degradation of lignin sulfonate obtained from a local paper plant. Through simultaneous reaction-extraction pathways applying dialysis filtration and highly porous polystyrene divinylbenzene adsorbent resin (HR-P for solid phase extraction (SPE, an attempt has been made to isolate smaller molecules produced from photocatalytic degradation. Moreover relatively high lignin sulfonate (0.5 g/L concentrations are used in the reactions. UV-Vis spectroscopy revealed a faster reduction in the concentration values for the aliphatic moiety compared to the aromatic moiety. Peaks were observed by both fluorescence spectroscopy and HPLC suggesting the production of new substances and fluorophores.

  17. Acidolysis of terebinth fruit oil with palmitic and caprylic acids in a recirculating packed bed reactor: optimization using response surface methodology

    Directory of Open Access Journals (Sweden)

    Koçak Yanık, D.

    2016-06-01

    Full Text Available The acidolysis reaction of terebinth fruit oil with caprylic and palmitic acid has been investigated. The reaction was catalyzed by lipase (Lipozyme IM from Rhizomucormiehei and carried out in recirculating packed bed reactor. The effects of reaction parameters have been analyzed using response surface methodology. Reaction time (3.5–6.5 h, enzyme load (10–20%, substrate flow rate (4–8 mL·min-1 and substrate mole ratios (Terebinth oil : Palmitic acid : Caprylic acid, 1:1.83:1.22–1:3.07:2.05 were evaluated. The optimum reaction conditions were 5.9 h reaction time, 10% enzyme load, 4 mL·min-1 substrate flow rate and 1:3.10:2.07 substrate mole ratio. The structured lipid obtained at these optimum conditions had 52.23% desired triacylglycerols and a lower caloric value than that of terebinth fruit oil. The melting characteristics and microstructure of the structured lipid were similar to those of commercial margarine fat extracts. The results showed that the structured lipid had the highest oxidative stability among the studied fats.Se ha investigado la reacción de acidolisis del aceite de pistacho con los ácidoscaprílico y palmítico. La reacción fue catalizada por la lipasa Lipozyme IM de Rhizomucormiehei y realizada mediante recirculación del reactor de lecho compacto. Los efectos de los parámetros de la reacción han sido analizados mediante el uso de la metodología de superficie de respuesta. El tiempo de reacción (3.5 hasta 6.5 h, la carga de enzima (10–20%, el caudal de sustrato (4–8 mL·min-1 relaciones molares de los sustrato (aceite de pistacho: ácido palmítico: ácido caprílico, 1: 1,83: 1,22–1: 3,07: 2,05 fueron evaluados. Las condiciones óptimas de reacción fueron 5,9 h de tiempo de reacción, el 10% de carga de la enzima, 4 mL·min-1 de caudal de sustrato y 1: 3,10: 2,07 de relación molar de sustratos. Los lípidos estructurados obtenidos en las condiciones óptimas tenías 52,23% de triacilgliceroles

  18. Condensation in Nanoporous Packed Beds.

    Science.gov (United States)

    Ally, Javed; Molla, Shahnawaz; Mostowfi, Farshid

    2016-05-10

    In materials with tiny, nanometer-scale pores, liquid condensation is shifted from the bulk saturation pressure observed at larger scales. This effect is called capillary condensation and can block pores, which has major consequences in hydrocarbon production, as well as in fuel cells, catalysis, and powder adhesion. In this study, high pressure nanofluidic condensation studies are performed using propane and carbon dioxide in a colloidal crystal packed bed. Direct visualization allows the extent of condensation to be observed, as well as inference of the pore geometry from Bragg diffraction. We show experimentally that capillary condensation depends on pore geometry and wettability because these factors determine the shape of the menisci that coalesce when pore filling occurs, contrary to the typical assumption that all pore structures can be modeled as cylindrical and perfectly wetting. We also observe capillary condensation at higher pressures than has been done previously, which is important because many applications involving this phenomenon occur well above atmospheric pressure, and there is little, if any, experimental validation of capillary condensation at such pressures, particularly with direct visualization.

  19. Using atomic layer deposited tungsten to increase thermal conductivity of a packed bed

    Energy Technology Data Exchange (ETDEWEB)

    Van Norman, Staci A.; Falconer, John L.; Weimer, Alan W., E-mail: alan.weimer@colorado.edu [Department of Chemical and Biological Engineering, University of Colorado, UCB 596, Boulder, Colorado 80309-0596 (United States); Tringe, Joseph W.; Sain, John D. [Lawrence Livermore National Laboratory, 7000 East Ave, Livermore, California 94550 (United States); Yang, Ronggui [Department of Mechanical Engineering, University of Colorado, UCB 427, Boulder, Colorado 80309-0427 (United States)

    2015-04-13

    This study investigated the effective thermal conductivity (k{sub eff}) of packed-beds that contained porous particles with nanoscale tungsten (W) films of different thicknesses formed by atomic layer deposition (ALD). A continuous film on the particles is vital towards increasing k{sub eff} of the packed beds. For example, the k{sub eff} of an alumina packed bed was increased by three times after an ∼8-nm continuous W film with 20 cycles of W ALD, whereas k{sub eff} was decreased on a polymer packed bed with discontinuous, evenly dispersed W-islands due to nanoparticle scattering of phonons. For catalysts, understanding the thermal properties of these packed beds is essential for developing thermally conductive supports as alternatives to structured supports.

  20. Biodegradation of phenolic waste liquors in stirred-tank, packed-bed, and fluidized-bed bioreactors

    Energy Technology Data Exchange (ETDEWEB)

    Holladay, D W; Hancher, G W; Chilcote, D D; Scott, C D

    1978-11-01

    The biological degradation of phenolic scrub liquors similar to those that arise in coal conversion processes was studied for symbiotic bacterial populations contained in a continuously stirred tank bioreactor, a three-phase packed-bed bioreactor, and a three-phase, fluidized-bed bioreactor. The conversions of phenol compounds were comparable in the three-phase, packed-bed bioreactor and the continuously stirred tank bioreactor; however, the packed-bed bioreactor degradation rates were as much as twice those in the continuously stirred tank bioreactor, and packed-bed bioreactor retention times were as low as one- tenth those of the continuously stirred tank bioreactors (minimum time was 12 hours).

  1. CLC in packed beds using syngas and CuO/Al2O3: model description and experimental validation

    NARCIS (Netherlands)

    Hamers, H.P.; Gallucci, F.; Cobden, P.D.; Kimball, E.; Sint Annaland, M. van

    2014-01-01

    The objective of this work is to study the performance of the oxygen carrier in a packed bed with periodic switching between oxidizing and reducing conditions. In this paper the performance of CuO/Al2O3 as the oxygen carrier in a packed bed reactor with syngas as the fuel are investigated, while

  2. Accumulation of BSA in Packed-bed Microfluidics

    Science.gov (United States)

    Summers, Samantha; Hu, Chuntian; Hartman, Ryan

    2012-11-01

    Alzheimers and Parkinsons are two diseases that are associated with protein deposition in the brain, causing loss of either cognitive or muscle functioning. Protein deposition diseases are considered progressive diseases since the continual aggregation of protein causes the patient's symptoms to slowly worsen over time. There are currently no known means of treatment for protein deposition diseases. Our goal is to understand the potential for packed-bed microfluidics to study protein accumulation. Measurement of the resistance to flow through micro-scale packed-beds is critical to understanding the process of protein accumulation. Aggregation in bulk is fundamentally different from accumulation on surfaces. Our study attempts to distinguish between either mechanism. The results from our experiments involving protein injection through a microfluidic system will be presented and discussed. Funding received by NSF REU Grant 1062611.

  3. Adiabatic Compressed Air Energy Storage with packed bed thermal energy storage

    International Nuclear Information System (INIS)

    Barbour, Edward; Mignard, Dimitri; Ding, Yulong; Li, Yongliang

    2015-01-01

    Highlights: • The paper presents a thermodynamic analysis of A-CAES using packed bed regenerators. • The packed beds are used to store the compression heat. • A numerical model is developed, validated and used to simulate system operation. • The simulated efficiencies are between 70.5% and 71.1% for continuous operation. • Heat build-up in the beds reduces continuous cycle efficiency slightly. - Abstract: The majority of articles on Adiabatic Compressed Air Energy Storage (A-CAES) so far have focussed on the use of indirect-contact heat exchangers and a thermal fluid in which to store the compression heat. While packed beds have been suggested, a detailed analysis of A-CAES with packed beds is lacking in the available literature. This paper presents such an analysis. We develop a numerical model of an A-CAES system with packed beds and validate it against analytical solutions. Our results suggest that an efficiency in excess of 70% should be achievable, which is higher than many of the previous estimates for A-CAES systems using indirect-contact heat exchangers. We carry out an exergy analysis for a single charge–storage–discharge cycle to see where the main losses are likely to transpire and we find that the main losses occur in the compressors and expanders (accounting for nearly 20% of the work input) rather than in the packed beds. The system is then simulated for continuous cycling and it is found that the build-up of leftover heat from previous cycles in the packed beds results in higher steady state temperature profiles of the packed beds. This leads to a small reduction (<0.5%) in efficiency for continuous operation

  4. Numerical simulation and experimental verification of gas flow through packed beds

    International Nuclear Information System (INIS)

    Natarajan, S.; Zhang, C.; Briens, C.

    2003-01-01

    This work is concerned with finding out an effective way of eliminating oxygen from a packed bed of monomer particles. This process finds application in industries involved in the manufacture of Nylon12. In the manufacture of the polymer Nylon12, the polymerization reaction is hindered by the presence of oxygen. Therefore, the main objective of this study is to get rid of the oxygen by injecting nitrogen to displace the oxygen from the voids in-between the monomer particles before they are introduced into the polymerization reactor. This work involves the numerical simulation and experimental verification of the flow in a packed bed. In addition, a parametric study is carried out for the parameters such as the number of injectors, the radial position of injectors, and the position of the injectors along the circumference of the packed bed to find out the best possible combination for effective elimination of the oxygen. Nitrogen does not interact with the monomer particles and hence there is no chemical reaction involved in this process. The nitrogen is introduced into the packed bed at a flow rate which will keep the superficial velocity well below the minimum fluidization velocity of the monomer particles. The packed bed will be modeled using a porous medium approach available in the commercial computational fluid dynamics (CFD) software FLUENT. The fluid flow inside the packed bed will be a multicomponent gas flow through a porous medium. The simulation results are validated by comparing with the experimental results. (author)

  5. Hydrogenation of furfural at the dynamic Cu surface of CuOCeO2/Al2O3 in vapor phase packed bed reactor

    Science.gov (United States)

    The hydrogenation of furfural to furfuryl alcohol over a CuOCeO2/'-Al2O3 catalyst in a flow reactor is reported. The catalyst was prepared by the wet impregnation of Cu onto a CeO2/'-Al2O3 precursor. The calcined catalyst was then treated with HNO3 to remove surface CuO resulting in a mixed CuCe oxi...

  6. Recent progress in the use of in situ X-ray methods for the study of heterogeneous catalysts in packed-bed capillary reactors

    NARCIS (Netherlands)

    Jacques, S.D.M.; Leynaud, O.; Strusevich, D.; Stukas, P.; Barnes, P.; Sankar, G.; Sheehy, M.; O’Brien, M.G.; Iglesias-Juez, A.; Beale, A.M.

    2009-01-01

    Synchrotron-based X-ray techniques, such as Diffraction and Absorption Spectroscopy (XAS), can be readily employed to study catalysts in action, thereby offering great potential for revealing the mechanism and behaviour of catalytic solids both during preparation and reaction. The continued

  7. Direct contact condensation in packed beds

    Energy Technology Data Exchange (ETDEWEB)

    Li, Yi; Klausner, James F.; Mei, Renwei; Knight, Jessica [Department of Mechanical and Aerospace Engineering, University of Florida, Gainesville, FL 32611 (United States)

    2006-12-15

    A diffusion driven desalination process was recently described where a very effective direct contact condenser with a packed bed is used to condense water vapor out of an air/vapor mixture. A laboratory scale direct contact condenser has been fabricated as a twin tower structure with two stages, co-current and countercurrent. Experiments have been operated in each stage with respective saturated air inlet temperatures of 36, 40 and 43{sup o}C. The temperature and humidity data have been collected at the inlet and exit of the packed bed for different water to air mass flow ratios that vary between 0 and 2.5. A one-dimensional model based on conservation principles has been developed, which predicts the variation of temperature, humidity, and condensation rate through the condenser stages. Agreement between the model and experiments is very good. It is observed that the countercurrent flow stage condensation effectiveness is significantly higher than that for the co-current stage. The condensation heat and mass transfer rates were found to decrease when water blockages occur within the packed bed. Using high-speed digital cinematography, it was observed that this problem can occur at any operating condition, and is dependent on the packing surface wetting characteristics. This observation is used to explain the requirement for two different empirical constants, depending on packing diameter, suggested by Onda for the air side mass transfer coefficient correlation. (author)

  8. Percolation behavior of tritiated water into a soil packed bed

    Energy Technology Data Exchange (ETDEWEB)

    Honda, T.; Katayama, K.; Uehara, K.; Fukada, S. [Interdisciplinary Graduate School of Engineering Sciences, Kyushu University, Kasuga, Fukuoka (Japan); Takeishi, T. [Faculty of Engineering, Kyushu University, Motooka Nishi-ku, Fukuoka (Japan)

    2015-03-15

    A large amount of cooling water is used in a D-T fusion reactor. The cooling water will contain tritium with high concentration because tritium can permeate metal walls at high temperature easily. A development of tritium handling technology for confining tritiated water in the fusion facility is an important issue. In addition, it is also important to understand tritium behavior in environment assuming severe accidents. In this study, percolation experiments of tritiated water in soil packed bed were carried out and tritium behavior in soil was discussed. Six soil samples were collected in Hakozaki campus of Kyushu University. These particle densities were of the same degree as that of general soils and moisture contents were related to BET surface area. For two soil samples used in the percolation experiment of tritiated water, saturated hydraulic conductivity agreed well with the estimating value by Creager. Tritium retention ratio in the soil packed bed was larger than water retention. This is considered to be due to an effect of tritium sorption on the surface of soil particles. The isotope exchange capacity estimated by assuming that H/T ratio of supplied tritiated water and H/T ratio of surface water of soil particle was equal was comparable to that on cement paste and mortar which were obtained by exposure of tritiated water vapor. (authors)

  9. Percolation behavior of tritiated water into a soil packed bed

    International Nuclear Information System (INIS)

    Honda, T.; Katayama, K.; Uehara, K.; Fukada, S.; Takeishi, T.

    2015-01-01

    A large amount of cooling water is used in a D-T fusion reactor. The cooling water will contain tritium with high concentration because tritium can permeate metal walls at high temperature easily. A development of tritium handling technology for confining tritiated water in the fusion facility is an important issue. In addition, it is also important to understand tritium behavior in environment assuming severe accidents. In this study, percolation experiments of tritiated water in soil packed bed were carried out and tritium behavior in soil was discussed. Six soil samples were collected in Hakozaki campus of Kyushu University. These particle densities were of the same degree as that of general soils and moisture contents were related to BET surface area. For two soil samples used in the percolation experiment of tritiated water, saturated hydraulic conductivity agreed well with the estimating value by Creager. Tritium retention ratio in the soil packed bed was larger than water retention. This is considered to be due to an effect of tritium sorption on the surface of soil particles. The isotope exchange capacity estimated by assuming that H/T ratio of supplied tritiated water and H/T ratio of surface water of soil particle was equal was comparable to that on cement paste and mortar which were obtained by exposure of tritiated water vapor. (authors)

  10. Method for immobilizing particulate materials in a packed bed

    Science.gov (United States)

    Even, Jr., William R.; Guthrie, Stephen E.; Raber, Thomas N.; Wally, Karl; Whinnery, LeRoy L.; Zifer, Thomas

    1999-01-01

    The present invention pertains generally to immobilizing particulate matter contained in a "packed" bed reactor so as to prevent powder migration, compaction, coalescence, or the like. More specifically, this invention relates to a technique for immobilizing particulate materials using a microporous foam-like polymer such that a) the particulate retains its essential chemical nature, b) the local movement of the particulate particles is not unduly restricted, c) bulk powder migration and is prevented, d) physical and chemical access to the particulate is unchanged over time, and e) very high particulate densities are achieved. The immobilized bed of the present invention comprises a vessel for holding particulate matter, inlet and an outlet ports or fittings, a loosely packed bed of particulate material contained within the vessel, and a three dimensional porous matrix for surrounding and confining the particles thereby fixing the movement of individual particle to a limited local position. The established matrix is composed of a series of cells or chambers comprising walls surrounding void space, each wall forming the wall of an adjacent cell; each wall containing many holes penetrating through the wall yielding an overall porous structure and allowing useful levels of gas transport.

  11. A CFD model for biomass combustion in a packed bed furnace

    Energy Technology Data Exchange (ETDEWEB)

    Karim, Md. Rezwanul [Faculty of Science, Engineering and Technology, Swinburne University of Technology, VIC 3122 (Australia); Department of Mechanical & Chemical Engineering, Islamic University of Technology, Gazipur 1704 (Bangladesh); Ovi, Ifat Rabbil Qudrat [Department of Mechanical & Chemical Engineering, Islamic University of Technology, Gazipur 1704 (Bangladesh); Naser, Jamal, E-mail: jnaser@swin.edu.au [Faculty of Science, Engineering and Technology, Swinburne University of Technology, VIC 3122 (Australia)

    2016-07-12

    Climate change has now become an important issue which is affecting environment and people around the world. Global warming is the main reason of climate change which is increasing day by day due to the growing demand of energy in developed countries. Use of renewable energy is now an established technique to decrease the adverse effect of global warming. Biomass is a widely accessible renewable energy source which reduces CO{sub 2} emissions for producing thermal energy or electricity. But the combustion of biomass is complex due its large variations and physical structures. Packed bed or fixed bed combustion is the most common method for the energy conversion of biomass. Experimental investigation of packed bed biomass combustion is difficult as the data collection inside the bed is challenging. CFD simulation of these combustion systems can be helpful to investigate different operational conditions and to evaluate the local values inside the investigation area. Available CFD codes can model the gas phase combustion but it can’t model the solid phase of biomass conversion. In this work, a complete three-dimensional CFD model is presented for numerical investigation of packed bed biomass combustion. The model describes the solid phase along with the interface between solid and gas phase. It also includes the bed shrinkage due to the continuous movement of the bed during solid fuel combustion. Several variables are employed to represent different parameters of solid mass. Packed bed is considered as a porous bed and User Defined Functions (UDFs) platform is used to introduce solid phase user defined variables in the CFD. Modified standard discrete transfer radiation method (DTRM) is applied to model the radiation heat transfer. Preliminary results of gas phase velocity and pressure drop over packed bed have been shown. The model can be useful for investigation of movement of the packed bed during solid fuel combustion.

  12. Investigations on a new internally-heated tubular packed-bed methanol–steam reformer

    KAUST Repository

    Nehe, Prashant

    2015-05-01

    Small-scale reformers for hydrogen production through steam reforming of methanol can provide an alternative solution to the demand of continuous supply of hydrogen gas for the operation of Proton Exchange Membrane Fuel Cells (PEMFCs). A packed-bed type reformer is one of the potential designs for such purpose. An externally heated reformer has issues of adverse lower temperature in the core of the reformer and significant heat loss to the environment thus impacting its performance. Experimental and numerical studies on a new concept of internally heated tubular packed-bed methanol-steam reformer have been reported in this paper with improved performance in terms of higher methanol conversion and reduced heat losses to surroundings. CuO/ZnO/Al2O3 is used as the catalyst for the methanol-steam reforming reaction and a rod-type electric heater at the center of the reactor is used for supplying necessary heat for endothermic steam reforming reaction. The vaporizer and the reformer unit with a constant volume catalyst bed are integrated in the annular section of a tubular reformer unit. The performance of the reformer was investigated at various operating conditions like feed rate of water-methanol mixture, mass of the catalyst and reforming temperature. The experimental and numerical results show that the methanol conversion and CO concentration increase with internal heating for a wide range of operating conditions. The developed reformer unit generates 50-80W (based on lower heating value) of hydrogen gas for applications in PEMFCs. For optimized design and operating conditions, the reformer unit produced 298sccm reformed gas containing 70% H2, 27% CO2 and 3% CO at 200-240°C which can produce a power output of 25-32W assuming 60% fuel cell efficiency and 80% of hydrogen utilization in a PEMFC. © 2015 Hydrogen Energy Publications, LLC.

  13. A biphasic oxidation of alcohols to aldehydes and ketones using a simplified packed-bed microreactor

    Directory of Open Access Journals (Sweden)

    Andrew Bogdan

    2009-04-01

    Full Text Available We demonstrate the preparation and characterization of a simplified packed-bed microreactor using an immobilized TEMPO catalyst shown to oxidize primary and secondary alcohols via the biphasic Anelli-Montanari protocol. Oxidations occurred in high yields with great stability over time. We observed that plugs of aqueous oxidant and organic alcohol entered the reactor as plugs but merged into an emulsion on the packed-bed. The emulsion coalesced into larger plugs upon exiting the reactor, leaving the organic product separate from the aqueous by-products. Furthermore, the microreactor oxidized a wide range of alcohols and remained active in excess of 100 trials without showing any loss of catalytic activity.

  14. Continuous biological waste gas treatment in stirred trickle-bed reactor with discontinuous removal of biomass.

    Science.gov (United States)

    Laurenzis, A; Heits, H; Wübker, S; Heinze, U; Friedrich, C; Werner, U

    1998-02-20

    A new reactor for biological waste gas treatment was developed to eliminate continuous solvents from waste gases. A trickle-bed reactor was chosen with discontinuous movement of the packed bed and intermittent percolation. The reactor was operated with toluene as the solvent and an optimum average biomass concentration of between 5 and 30 kg dry cell weight per cubic meter packed bed (m3pb). This biomass concentration resulted in a high volumetric degradation rate. Reduction of surplus biomass by stirring and trickling caused a prolonged service life and prevented clogging of the trickle bed and a pressure drop increase. The pressure drop after biomass reduction was almost identical to the theoretical pressure drop as calculated for the irregular packed bed without biomass. The reduction in biomass and intermittent percolation of mineral medium resulted in high volumetric degradation rates of about 100 g of toluene m-3pb h-1 at a load of 150 g of toluene m-3pb h-1. Such a removal rate with a trickle-bed reactor was not reported before. Copyright 1998 John Wiley & Sons, Inc.

  15. Experimental study of gas–liquid two-phase flow through packed bed under natural circulation conditions

    International Nuclear Information System (INIS)

    Chen, Shao-Wen; Miwa, Shuichiro; Griffiths, Matt

    2016-01-01

    Dry-out phenomena in packed beds or porous media may cause a significant digression of cooling/reaction performance in heat transfer/chemical reactor systems. One of the phenomena responsible for the dry-out in packed beds is known as the counter-current flow limitation (CCFL). In order to investigate the CCFL phenomena induced by gas–liquid two-phase flow in packed beds inside a pool, a natural circulation packed bed test facility was designed and constructed. A total of 27 experimental conditions covering various packing media sizes (sphere diameters: 3.0, 6.4 and 9.5 mm), packed bed heights (15, 35 and 50 cm) and water level heights (1.0, 1.5 and 2.0 m) were tested to examine the CCFL criteria with adiabatic air–water two-phase flow under natural circulation conditions. Both CCFL and flow reversal phenomena were observed, and the experimental data including instantaneous and time-averaged void fraction, differential pressure and superficial gas–liquid velocities were collected. The CCFL criteria were determined when periodical oscillations of void fraction and differential pressure appear. In addition, the Wallis correlation for CCFL was utilized for data analysis, and the Wallis coefficient, C, was determined experimentally from the packed bed CCFL tests. Compared to the existing data-sets in literature, the higher C values obtained in the present experiment suggest a possibly higher dry-out heat flux for natural circulation debris systems, which may be due to the water supply from both top and bottom surfaces of the packed beds. Considering the effects of bed height and hydraulic diameter of the packing media, a newly developed model for the Wallis coefficient, C, under natural circulation CCFL is presented. The present model can predict the experimental data with an averaged absolute error of ±7.9%. (author)

  16. Continuous Heterogeneous Photocatalysis in Serial Micro-Batch Reactors.

    Science.gov (United States)

    Pieber, Bartholomäus; Shalom, Menny; Antonietti, Markus; Seeberger, Peter H; Gilmore, Kerry

    2018-01-29

    Solid reagents, leaching catalysts, and heterogeneous photocatalysts are commonly employed in batch processes but are ill-suited for continuous-flow chemistry. Heterogeneous catalysts for thermal reactions are typically used in packed-bed reactors, which cannot be penetrated by light and thus are not suitable for photocatalytic reactions involving solids. We demonstrate that serial micro-batch reactors (SMBRs) allow for the continuous utilization of solid materials together with liquids and gases in flow. This technology was utilized to develop selective and efficient fluorination reactions using a modified graphitic carbon nitride heterogeneous catalyst instead of costly homogeneous metal polypyridyl complexes. The merger of this inexpensive, recyclable catalyst and the SMBR approach enables sustainable and scalable photocatalysis. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Integration of coal gasification and packed bed CLC for high efficiency and near-zero emission power generation

    NARCIS (Netherlands)

    Spallina, V.; Romano, M.C.; Chiesa, P.; Gallucci, F.; Sint Annaland, van M.; Lozza, G.

    2014-01-01

    A detailed thermodynamic analysis has been carried out of large-scale coal gasification-based power plant cycles with near zero CO2 emissions, integrated with chemical looping combustion (CLC). Syngas from coal gasification is oxidized in dynamically operated packed bed reactors (PBRs), generating a

  18. Local description of the energy transfer process in a packed bed heat exchanger

    International Nuclear Information System (INIS)

    Costa, M.L.M.; Sampaio, R.; Gama, R.M.S. da.

    1990-01-01

    The energy transfer process in a packed-bed heat exchanger, in counter0flow arrangement is considered. The phenomenon is described through a Continuum Theory of Mixtures approach, in which fluid and solid (porous matrix) are regarded as continuous constituents possessing, each one, its own temperature and velocity fields. The heat 'exchangers consists of two channels, separated by an impermeable wall without thermal resistence, in which there exists a saturated flow. Some particular cases are simulated. (author)

  19. Tritium sorption behavior on the percolation of tritiated water into a soil packed bed

    Energy Technology Data Exchange (ETDEWEB)

    Furuichi, Kazuya, E-mail: kfuruichi@aees.kyushu-u.ac.jp [Department of Advanced Energy Engineering, Kyushu University, 6-1, Kasuga-koen, Kasuga, Fukuoka 816-8580 (Japan); Katayama, Kazunari; Date, Hiroyuki [Department of Advanced Energy Engineering, Kyushu University, 6-1, Kasuga-koen, Kasuga, Fukuoka 816-8580 (Japan); Takeishi, Toshiharu [Factory of Engineering, Kyushu University, 744 Motooka Nishi-ku, Fukuoka 819-0395 (Japan); Fukada, Satoshi [Department of Advanced Energy Engineering, Kyushu University, 6-1, Kasuga-koen, Kasuga, Fukuoka 816-8580 (Japan)

    2016-11-01

    Highlights: • We establish the permeation model of tritiated water in the soil layer. • Saturated hydraulic conductivity of water in soil was gained by using the model. • The isotope exchange reaction coefficient was good agreement with experimental data. - Abstract: Development of tritium transport model in natural soil is an important issue from a viewpoint of safety of fusion reactors. The spill of a large amount of tritiated water to the environment is a concern accident because huge tritiated water is handled in a fusion plant. In this work, a simple tritium transport model was proposed based on the tritium transport model in porous materials. The overall mass transfer coefficient representing isotope exchange reaction between tritiated water and structural water in soil particles was obtained by numerically analyzing the result of the percolation experiment of tritiated water into the soil packed bed. Saturated hydraulic conductivity in the natural soil packed bed was obtained to be 0.033 mm/s. By using this value, the overall mass transfer capacity coefficients representing the isotope exchange reaction between tritiated water percolating through the packed bed and overall structural water on soil particles was determined to be 6.0 × 10{sup −4} 1/s. This value is much smaller than the mass transfer capacity coefficient between tritiated water vapor and water on concrete material and metals.

  20. Abatement of toluene from gas streams via ferro-electric packed bed dielectric barrier discharge plasma.

    Science.gov (United States)

    Liang, Wenjun; Li, Jian; Li, Jie; Jin, Yuquan

    2009-10-30

    Destruction of gaseous toluene via ferro-electric packed bed dielectric barrier discharge plasma in a coaxial cylindrical reactor was carried out at atmospheric pressure and room temperature. The difference among three kinds of reactors was compared in terms of specific energy density (SED), energy yield (EY), toluene decomposition. In order to optimize the geometry of the reactor, the removal efficiency of toluene was compared for various inner electrode diameters. In addition, qualitative analysis on by-products and particular discussion on toluene abatement mechanisms were also presented. It has been found that ferro-electric packed bed DBD reactor could effectively decompose toluene. Toluene removal efficiency enhanced with increasing SED. With respect to toluene conversion, 1.62 mm electrode appeared to be superior to 1.06 mm electrodes. BaTiO3 reactor had the highest toluene removal efficiency among the reactors. For NaNO2 reactor, the highest EY could reach 17.0 mg/kWh to a certain extent.

  1. Abatement of toluene from gas streams via ferro-electric packed bed dielectric barrier discharge plasma

    International Nuclear Information System (INIS)

    Liang Wenjun; Li Jian; Li Jie; Jin Yuquan

    2009-01-01

    Destruction of gaseous toluene via ferro-electric packed bed dielectric barrier discharge plasma in a coaxial cylindrical reactor was carried out at atmospheric pressure and room temperature. The difference among three kinds of reactors was compared in terms of specific energy density (SED), energy yield (EY), toluene decomposition. In order to optimize the geometry of the reactor, the removal efficiency of toluene was compared for various inner electrode diameters. In addition, qualitative analysis on by-products and particular discussion on toluene abatement mechanisms were also presented. It has been found that ferro-electric packed bed DBD reactor could effectively decompose toluene. Toluene removal efficiency enhanced with increasing SED. With respect to toluene conversion, 1.62 mm electrode appeared to be superior to 1.06 mm electrodes. BaTiO 3 reactor had the highest toluene removal efficiency among the reactors. For NaNO 2 reactor, the highest EY could reach 17.0 mg/kWh to a certain extent.

  2. Numerical Simulation of Flow and Heat Transfer in Structured Packed Beds with Smooth or Dimpled Spheres at Low Channel to Particle Diameter Ratio

    Directory of Open Access Journals (Sweden)

    Shiyang Li

    2018-04-01

    Full Text Available Packed beds are widely used in catalytic reactors or nuclear reactors. Reducing the pressure drop and improving the heat transfer performance of a packed bed is a common research aim. The dimpled structure has a complex influence on the flow and heat transfer characteristics. In the present study, the flow and heat transfer characteristics in structured packed beds with smooth or dimpled spheres are numerically investigated, where two different low channel to particle diameter ratios (N = 1.00 and N = 1.15 are considered. The pressure drop and the Nusselt number are obtained. The results show that, for N = 1.00, compared with the structured packed bed with smooth spheres, the structured packed bed with dimpled spheres has a lower pressure drop and little higher Nusselt number at 1500 < ReH < 14,000, exhibiting an improved overall heat transfer performance. However, for N = 1.15, the structured packed bed with dimpled spheres shows a much higher pressure drop, which dominantly affects the overall heat transfer performance, causing it to be weaker. Comparing the different channel to particle diameter ratios, we find that different configurations can result in: (i completely different drag reduction effect; and (ii relatively less influence on heat transfer enhancement.

  3. Minimum Energy Dissipation under Cocurrent Flow in Packed Beds

    Czech Academy of Sciences Publication Activity Database

    Akramov, T.A.; Stavárek, Petr; Jiřičný, Vladimír; Staněk, Vladimír

    2011-01-01

    Roč. 50, č. 18 (2011), s. 10824-10832 ISSN 0888-5885 R&D Projects: GA ČR GA104/09/0880 Institutional research plan: CEZ:AV0Z40720504 Keywords : energy dissipation * current flow * packed bed Subject RIV: CI - Industrial Chemistry, Chemical Engineering Impact factor: 2.237, year: 2011

  4. Forced Convection Heat Transfer of a sphere in Packed Bed Arrangement

    International Nuclear Information System (INIS)

    Lee, Dong-Young; Chung, Bum-Jin

    2016-01-01

    This paper analysis and discuss the forced convective heat transfer from heated single sphere, which is buried in unheated packed bed, depending on Re d with porosity. The present work determines the test matrix for the packed bed experiment. And this study discuss difference of heat transfer according to the location of heated sphere and compared heated bed with heated sphere in packed bed and compared FCC (Face Centered Cubic), HCP (Hexagonal Closed Packed) structured packed bed with random packed. This paper is to discuss and make the plan to experiment the heat transfer for depending on location of heated single sphere in unheated packed bed, to compare single sphere in packed bed with heated packed bed and to compare the structured packed bed with random packed bed. The Nu d increase as heated single sphere is close to the wall and bottom because of increasing porosity and enhancing eddy motion respectively. The existing experiment of heated sphere in packed bed do not consider the preheating effect which decrease heat transfer on downstream. The heat transfer rate of structured packed bed is different from random packed bed because of unsteady flow in random packed bed. In this study, mass transfer experiments will replace heat transfer experiments based on analogy concept. An electroplating system is adopted using limiting current technique

  5. Forced Convection Heat Transfer of a sphere in Packed Bed Arrangement

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Dong-Young; Chung, Bum-Jin [Kyung Hee University, Yongin (Korea, Republic of)

    2016-10-15

    This paper analysis and discuss the forced convective heat transfer from heated single sphere, which is buried in unheated packed bed, depending on Re{sub d} with porosity. The present work determines the test matrix for the packed bed experiment. And this study discuss difference of heat transfer according to the location of heated sphere and compared heated bed with heated sphere in packed bed and compared FCC (Face Centered Cubic), HCP (Hexagonal Closed Packed) structured packed bed with random packed. This paper is to discuss and make the plan to experiment the heat transfer for depending on location of heated single sphere in unheated packed bed, to compare single sphere in packed bed with heated packed bed and to compare the structured packed bed with random packed bed. The Nu{sub d} increase as heated single sphere is close to the wall and bottom because of increasing porosity and enhancing eddy motion respectively. The existing experiment of heated sphere in packed bed do not consider the preheating effect which decrease heat transfer on downstream. The heat transfer rate of structured packed bed is different from random packed bed because of unsteady flow in random packed bed. In this study, mass transfer experiments will replace heat transfer experiments based on analogy concept. An electroplating system is adopted using limiting current technique.

  6. On the heat transfer in packed beds

    International Nuclear Information System (INIS)

    Sordon, G.

    1988-09-01

    The design of a fusion reactor blanket concept based on a bed of lithium containing ceramic pebbles or a mixture of ceramic and beryllium pebbles demands the knowledge of the effective thermal conductivity of pebble beds, including beds formed by a binary mixture of high conducting metallic pebbles and poorly conducting pebbles. In this work, binary mixtures of spheres of same diameter and different conductivities as well as beds formed by one type of spheres were investigated. The experimental apparatus consists of a stainless steel cylinder with a heating rod along the symmetry axis. Experiments with stagnant and flowing gas were performed. The pebbles were of Al 2 O 3 (diameter = 1, 2, 4 mm), of Li 4 SO 4 (diameter = 0.5 mm) of Al (diameter = 2 mm) and of steel (diameter = 2, 4 mm). Experimental values of the thermal conductivity and of the wall heat transfer coefficient are compared with the predicted ones. Modifications of already existing models were suggested. (orig.) [de

  7. Simulation of turbulent flow in a packed bed

    Energy Technology Data Exchange (ETDEWEB)

    Guo, B.; Yu, A. [Centre for Simulation and Modelling of Particulate Systems and School of Material Science and Engineering, The University of New South Wales, Sydney 2052 (Australia); Wright, B.; Zulli, P. [BlueScope Steel Research Laboratories, P.O. Box 202, Port Kembla, NSW 2505 (Australia)

    2006-05-15

    Numerous models for simulating the flow and transport in packed beds have been proposed in the literature with few reported applications. In this paper, several turbulence models for porous media are applied to the gas flow through a randomly packed bed and are examined by means of a parametric study against some published experimental data. These models predict widely different turbulent eddy viscosity. The analysis also indicates that deficiencies exist in the formulation of some model equations and selection of a suitable turbulence model is important. With this realization, residence time distribution and velocity distribution are then simulated by considering a radial profile of porosity and turbulence induced dispersion, and the results are in good agreement with the available experimental data. (Abstract Copyright [2006], Wiley Periodicals, Inc.)

  8. Continuous proline catalysis via leaching of solid proline

    Directory of Open Access Journals (Sweden)

    Suzanne M. Opalka

    2011-12-01

    Full Text Available Herein, we demonstrate that a homogeneous catalyst can be prepared continuously via reaction with a packed-bed of a catalyst precursor. Specifically, we perform continuous proline catalyzed α-aminoxylations using a packed-bed of L-proline. The system relies on a multistep sequence in which an aldehyde and thiourea additive are passed through a column of solid proline, presumably forming a soluble oxazolidinone intermediate. This transports a catalytic amount of proline from the packed-bed into the reactor coil for subsequent combination with a solution of nitrosobenzene, affording the desired optically active α-aminooxy alcohol after reduction. To our knowledge, this is the first example in which a homogeneous catalyst is produced continuously using a packed-bed. We predict that the method will not only be useful for other L-proline catalyzed reactions, but we also foresee that it could be used to produce other catalytic species in flow.

  9. Microbial sulfate reduction under sequentially acidic conditions in an upflow anaerobic packed bed bioreactor

    Energy Technology Data Exchange (ETDEWEB)

    Jong, T.; Parry, D.L. [Charles Darwin University, Darwin, NT (Australia). Faculty for Educational Health & Science

    2006-07-15

    The aim of this study was to operate an upflow anaerobic packed bed reactor (UAPB) containing sulfate reducing bacteria (SRB) under acidic conditions similar to those found in acid mine drainage (AMD). The UAPB was filled with sand and operated under continuous flow at progressively lower pH and was shown to be capable of supporting sulfate reduction at pH values of 6.0, 5.0, 4.5, 4.0 and 3.5 in a synthetic medium containing 53.5 mmol l{sup -1} lactate. Sulfate reduction rates of 553-1052 mmol m{sup -3} d{sup -1} were obtained when the influent solution pH was progressively lowered from pH 6.0 to 4.0, under an optimal flow rate of 2.61 ml min{sup -1}. When the influent pH was further lowered to pH 3.5, sulfate reduction was substantially reduced with only about 1% sulfate removed at a rate of 3.35 mmol m{sup -3} d{sup -1} after 20 days of operation. However, viable SRB were recovered from the column, indicating that the SRB population was capable of surviving and metabolizing at low levels even at pH 3.5 conditions for at least 20 days. The changes in conductivity in the SRB column did not always occur with changes in pH and redox potential, suggesting that conductivity measurements may be more sensitive to SRB activity and could be used as an additional tool for monitoring SRB activity. The bioreactor containing SRB was able to reduce sulfate and generate alkalinity even when challenged with influent as low as pH 3.5, indicating that such treatment systems have potential for bioremediating highly acidic, sulfate contaminated waste waters.

  10. Co-current descending two-phase flows in inclined packed beds : experiments versus simulations

    Energy Technology Data Exchange (ETDEWEB)

    Atta, A.; Nigam, K.D.P.; Roy, S. [Inst. of Technology, New Delhi (India). Dept. of Chemical Engineering; Schubert, M.; Larachi, F. [Laval Univ., Quebec City, PQ (Canada). Dept. of Chemical Engineering

    2010-10-15

    This paper presented a numerical simulation for an inclined packed bed configuration for two-phase co-current downward flow. A two-phase Eulerian computational fluid dynamics (CFD) model was used to predict the hydrodynamic behaviour. Two different modelling strategies were compared, notably a straight tube with an artificially inclined gravity, and an inclined geometry with straight gravity. The effect of inclination angle of a packed bed on its gas-liquid flow segregation and liquid saturation spatial distribution was measured for varying inclinations and fluid velocities. The CFD model was adapted from a trickle-bed vertical configuration and based on the porous media concept. The predicted pressure drops for the inclined gravity were found to be insensitive to inclination. Therefore, simulations to study the parameters that influence the reduced liquid saturation were performed only with the inclined geometry case. Experimental data obtained using electrical capacitance tomography was used to validate the model predictions. The study showed that a trickle bed CFD model for vertically straight reactors can be effectively implemented in inclined reactor geometries. However, additional research is needed to formulate appropriate drag force closures which should be incorporated in the CFD model for improved quantitative estimation of inclined bed hydrodynamics. 22 refs., 10 figs.

  11. Desempenho de reator anaeróbio-aeróbio de leito fixo no tratamento de esgoto sanitário Performance of anaerobic-aerobic packed-bed reactor in the treatment of domestic sewage

    Directory of Open Access Journals (Sweden)

    Sérgio Brasil Abreu

    2008-06-01

    Full Text Available Este artigo relata a avaliação do desempenho de um reator anaeróbio-aeróbio, preenchido com espuma de poliuretano, para tratamento de esgoto sanitário. Inicialmente, foram testados diferentes tempos de detenção hidráulica (TDH no reator que operou apenas em condições anaeróbias. Em seguida, foi operado o reator combinado anaeróbio-aeróbio. O melhor resultado para o reator em operação exclusivamente anaeróbia foi para o TDH de 10 horas, no qual se conseguiu reduzir a DQO de 389 ± 70 mg/L para 137 ± 16 mg/L. Para o reator anaeróbio-aeróbio, a DQO foi reduzida de 259 ± 69 mg/L para 93 ± 31 mg/L para TDH de 12 h (6 h no estágio anaeróbio e 6 h no aeróbio. A comparação de todos os resultados obtidos evidenciou a importância do pós-tratamento aeróbio na remoção de parcela de matéria orgânica não removida em tratamento unicamente anaeróbio.This paper reports on the performance evaluation of an upflow anaerobic-aerobic reactor, filled with polyurethane matrices, for domestic sewage treatment. Initially, different hydraulic retention times were assayed with the reactor operating exclusively in anaerobic condition. Afterwards, anaerobic-aerobic combined reactor was operated. The anaerobic operation with HRT of 10 h provided the best organic matter removal with COD reduction from 389 ± 70 mg/L to 137 ± 16 mg/L. Under anaerobic-aerobic condition, the COD dropped from 259 ± 69 mg/L to 93 ± 31 mg/L with HRT of 12 h (6 h in anaerobic and 6 h in aerobic stages. Finally, comparing all the obtained results, it was possible to verify the importance of the aerobic post treatment in the removal of part of the organic matter not removed in an exclusively anaerobic treatment.

  12. Modelling heat transfer during flow through a random packed bed of spheres

    Science.gov (United States)

    Burström, Per E. C.; Frishfelds, Vilnis; Ljung, Anna-Lena; Lundström, T. Staffan; Marjavaara, B. Daniel

    2018-04-01

    Heat transfer in a random packed bed of monosized iron ore pellets is modelled with both a discrete three-dimensional system of spheres and a continuous Computational Fluid Dynamics (CFD) model. Results show a good agreement between the two models for average values over a cross section of the bed for an even temperature profiles at the inlet. The advantage with the discrete model is that it captures local effects such as decreased heat transfer in sections with low speed. The disadvantage is that it is computationally heavy for larger systems of pellets. If averaged values are sufficient, the CFD model is an attractive alternative that is easy to couple to the physics up- and downstream the packed bed. The good agreement between the discrete and continuous model furthermore indicates that the discrete model may be used also on non-Stokian flow in the transitional region between laminar and turbulent flow, as turbulent effects show little influence of the overall heat transfer rates in the continuous model.

  13. Carbon Sequestration in Olivine and Basalt Powder Packed Beds.

    Science.gov (United States)

    Xiong, Wei; Wells, Rachel K; Giammar, Daniel E

    2017-02-21

    Fractures and pores in basalt could provide substantial pore volume and surface area of reactive minerals for carbonate mineral formation in geologic carbon sequestration. In many fractures solute transport will be limited to diffusion, and opposing chemical gradients that form as a result of concentration differences can lead to spatial distribution of silicate mineral dissolution and carbonate mineral precipitation. Glass tubes packed with grains of olivine or basalt with different grain sizes and compositions were used to explore the identity and spatial distribution of carbonate minerals that form in dead-end one-dimensional diffusion-limited zones that are connected to a larger reservoir of water in equilibrium with 100 bar CO 2 at 100 °C. Magnesite formed in experiments with olivine, and Mg- and Ca-bearing siderite formed in experiments with flood basalt. The spatial distribution of carbonates varied between powder packed beds with different powder sizes. Packed beds of basalt powder with large specific surface areas sequestered more carbon per unit basalt mass than powder with low surface area. The spatial location and extent of carbonate mineral formation can influence the overall ability of fractured basalt to sequester carbon.

  14. Effects of electrode geometry on the performance of dielectric barrier/packed-bed discharge plasmas in benzene degradation

    International Nuclear Information System (INIS)

    Jiang, Nan; Lu, Na; Shang, Kefeng; Li, Jie; Wu, Yan

    2013-01-01

    Highlights: • Benzene was successfully degraded by dielectric barrier/packed-bed discharge plasmas. • Different electrode geometry has distinct effect on plasmas oxidation performance. • Benzene degradation and energy performance were enhanced when using the coil electrode. • The reaction products were well determined by online FTIR analysis. -- Abstract: In this study, the effects of electrode geometry on benzene degradation in a dielectric barrier/packed-bed discharge plasma reactor with different electrodes were systematically investigated. Three electrodes were employed in the experiments, these were coil, bolt, and rod geometries. The reactor using the coil electrode showed better performance in reducing the dielectric loss in the barrier compared to that using the bolt or rod electrodes. In the case of the coil electrode, both the benzene degradation efficiency and energy yield were higher than those for the other electrodes, which can be attributed to the increased role of surface mediated reactions. Irrespective of the electrode geometry, the packed-bed discharge plasma was superior to the dielectric barrier discharge plasma in benzene degradation at any specific applied voltage. The main gaseous products of benzene degradation were CO, CO 2 , H 2 O, and formic acid. Discharge products such as O 3 , N 2 O, N 2 O 5 , and HNO 3 were also detected in the outlet gas. Moreover, the presence of benzene inhibited the formation of ozone because of the competing reaction of oxygen atoms with benzene. This study is expected to offer an optimized approach combining dielectric barrier discharge and packed-bed discharge to improve the degradation of gaseous pollutants

  15. Practical study on the electrochemical simultaneous removal of copper and zinc from simulated binary-metallic industrial wastewater using a packed-bed cathode

    Directory of Open Access Journals (Sweden)

    Meshaal F. Alebrahim

    2017-06-01

    Full Text Available In this work, electrochemical-simultaneous removal of copper and zinc from simulated binary-metallic industrial wastewater containing different ratios of copper to zinc was studied using a packed-bed continuous-recirculation flow electrolytic reactor. The total nominal initial concentration of both metals, circulating rate of flow and nominal initial pH were held constant. Parameters affecting the removal percent and current efficiency of removal, such as applied current and time of electrolysis were investigated. Results revealed that increased current intensity accelerated the removal of metals and diminish current efficiency. It was also observed that selective removal of both metals is possible when the applied current was of small intensity. Moreover, the factors that led to loss of faradaic efficiency were discussed.

  16. Importance of spinel reaction kinetics in packed-bed chemical looping combustion using a CuO/Al2O3 oxygen carrier

    NARCIS (Netherlands)

    San Pio, M.A.; Sabatino, F.; Gallucci, F.; van Sint Annaland, M.

    2018-01-01

    Chemical looping combustion is especially competitive for electrical power generation with integrated CO2 capture when it is operated at high temperatures (1000–1200 °C) and high pressures (15 bar or higher). For these demanding conditions, dynamically operated packed bed reactors have been

  17. Optimum cadmium reactor designs for colorimetric determination of nitrate with flow injection and gas-segmented continuous flow analyzers

    International Nuclear Information System (INIS)

    Patton, C.J.

    1989-01-01

    Cadmium reactor types can be grouped into four categories: packed bed; filamentous; open tubular; and planar. Packed bed cadmium reactors, in the form of cadmium filings, granules, powder, or electrolytically precipitated needles packed into glass or polymeric tubes, are by far the most widely used for both FIA and CFA methods. Surprisingly, filamentous cadmium reactors, in the form of cadmium wire slipped into flexible polymeric tubing, have been reported for CFA applications only. Open tubular cadmium reactors, in the form of small diameter cadmium tubing coiled into a helix, have been fully characterized and described for CFA applications. A preliminary description of planar cadmium reactors, in the form of cadmium foil sandwiched between continuous flow dialyzer blocks has also been reported. In this presentation, each reactor type is evaluated in terms of cost, ease of use, reduction efficiency, and long-term stability. Factors that make some reactors more applicable to FIA than to CFA (or the reverse) are also discussed, and experimental data are presented

  18. Evaluation of a commercial packed bed flow hydrogenator for reaction screening, optimization, and synthesis

    Directory of Open Access Journals (Sweden)

    Marian C. Bryan

    2011-08-01

    Full Text Available The performance of the ThalesNano H-Cube®, a commercial packed bed flow hydrogenator, was evaluated in the context of small scale reaction screening and optimization. A model reaction, the reduction of styrene to ethylbenzene through a 10% Pd/C catalyst bed, was used to examine performance at various pressure settings, over sequential runs, and with commercial catalyst cartridges. In addition, the consistency of the hydrogen flow was indirectly measured by in-line UV spectroscopy. Finally, system contamination due to catalyst leaching, and the resolution of this issue, is described. The impact of these factors on the run-to-run reproducibility of the H-Cube® reactor for screening and reaction optimization is discussed.

  19. Numerical study on hygroscopic material drying in packed bed

    Directory of Open Access Journals (Sweden)

    M. Stakić

    2011-06-01

    Full Text Available The paper addresses numerical simulation for the case of convective drying of hygroscopic material in a packed bed, analyzing agreement between the simulated and the corresponding experimental results. In the simulation model of unsteady simultaneous one-dimensional heat and mass transfer between gas phase and dried material, it is assumed that the gas-solid interface is at thermodynamic equilibrium, while the drying rate of the specific product is calculated by applying the concept of a "drying coefficient". Model validation was done on the basis of the experimental data obtained with potato cubes. The obtained drying kinetics, both experimental and numerical, show that higher gas (drying agent velocities (flow-rates, as well as lower equivalent grain diameters, induce faster drying. This effect is more pronounced for deeper beds, because of the larger amount of wet material to be dried using the same drying agent capacity.

  20. Mass transfer controlled reactions in packed beds at low Reynolds numbers

    Energy Technology Data Exchange (ETDEWEB)

    Fedkiw, P.S.

    1978-12-01

    The a priori prediction and correlation of mass-transfer rates in transport limited, packed-bed reactors at low Reynolds numbers is examined. The solutions to the governing equations for a flow-through porous electrode reactor indicate that these devices must operate at a low space velocity to suppress a large ohmic potential drop. Packed-bed data for the mass-transfer rate at such low Reynolds numbers were examined and found to be sparse, especially in liquid systems. Prior models to simulate the solid-void structure in a bed are reviewed. Here the bed was envisioned as an array of sinusoidal periodically constricted tubes (PCT). Use of this model has not appeared in the literature. The velocity field in such a tube should be a good approximation to the converging-diverging character of the velocity field in an actual bed. The creeping flow velocity profiles were calculated. These results were used in the convective-diffusion equation to find mass transfer rates at high Peclet number for both deep and shallow beds, for low Peclet numbers in a deep bed. All calculations assumed that the reactant concentration at the tube surface is zero. Mass-transfer data were experimentally taken in a transport controlled, flow-through porous electrode to test the theoretical calculations and to provide data resently unavailable for deeper beds. It was found that the sinusoidal PCT model could not fit the data of this work or that available in the literature. However, all data could be adequately described by a model which incorporates a channelingeffect. The bed was successfully modeled as an array of dual sized straight tubes.

  1. THE EFFECT OF THE THICKNESS OF A PACKED BED ON THE DYNAMIC AND THERMAL BEHAVIOR OF A SOLAR DRYER

    Directory of Open Access Journals (Sweden)

    S KHALDI

    2015-06-01

    Full Text Available Drying food in the sun is a safe, easy and economical way to preserve food, especially fruits. Cabinet dryers are the most popular equipment for fruit drying. Because of intermittent nature of solar energy, storage is required for uninterrupted supply in order to match the needs. The main objective of this study is to assess effectiveness of continuous solar dryer integrated with packed bed as thermal storage with natural airflow for drying figs (Ficuscarica. The cabinet dryer were envisaged theoretically (computational fluid dynamics (CFD. The distribution of the velocity and temperature of air within the solar dryer were presented during one day of August and under the climate conditions of Tlemcen (Algeria.  The effects of presence of a packed bed on the distribution of velocity and temperature of airflow and on the temperature of figs were analyzed. The results show that the solar dryer design, incorporating a packed bed enhances the capabilities and performance of the solar dryer, through increasing time of drying.

  2. Experimental Study on Pressure Drop and Flow Dispersion in Packed Bed of Natural Zeolite

    Directory of Open Access Journals (Sweden)

    Ruya Petric Marc

    2018-01-01

    Full Text Available The use of conventional correlation for pressure drop and dispersion coefficient calculation may result in inaccurate values for zeolite packed bed as the correlations are generally developed for regularly shaped and uniformly sized particles. To support the research on the application of modified natural zeolite as tar cracking catalyst, the research on the hydrodynamic behaviour of zeolite packed bed has been conducted. Experiments were carried out using a glass column with diameter of 37.8 mm. Natural zeolite with particle size of about 2.91 to 6.4 mm was applied as packing material in the column, and the bed height was varied at 9, 19 and 29 cm. Air was used as the fluid that flows through the bed and nitrogen was used as a tracer for residence time distribution determination. Air flow rates were in the range of 20 to 100 mL/s which correspond to the laminar-transitional flow regime. The pressure drops through the bed were in the range of 1.7 to 95.6 Pa, depending on the air flow rate and bed height. From these values, the parameters in the Ergun equation were estimated, taking into account the contribution by wall effect when the ratio of column to particle diameter is low. The viscous and inertial term constants in the Ergun equation calculated ranges from 179 to 199 and 1.41 to 1.47 respectively while the particle sphericity ranges from 0.56 to 0.59. The reactor Peclet number were determined to range from 5.2 to 5.5, which indicated significant deviation from a plug flow condition.

  3. CLC in packed beds using syngas and CuO/Al2O3: Model description and experimental validation

    International Nuclear Information System (INIS)

    Hamers, H.P.; Gallucci, F.; Cobden, P.D.; Kimball, E.; Sint Annaland, M. van

    2014-01-01

    Highlights: • CLC with CuO/Al 2 O 3 and syngas and air has been demonstrated experimentally. • Model predicts accurately only if kinetics describe the complete solid reduction. • CuO/Al 2 O 3 is proven to catalyze the reversed water gas shift reaction. • H 2 O is more effective to suppress carbon deposition on CuO/Al 2 O 3 than CO 2 . • The OC reaction rate is not permanently affected by exposure to H 2 S. - Abstract: The objective of this work is to study the performance of the oxygen carrier in a packed bed with periodic switching between oxidizing and reducing conditions. In this paper the performance of CuO/Al 2 O 3 as the oxygen carrier in a packed bed reactor with syngas as the fuel are investigated, while also studying the (possible) carbon deposition and the effect of sulphur impurities on the stability of the carrier. Both experiments and simulations are used in this work. Cyclic experiments (oxidation with air and reduction with syngas) have been carried out in a lab scale packed bed reactor with 13 wt% CuO/Al 2 O 3 . The experimental results were well described by a 1D reactor model, provided that critical attention was given to the reaction rate for the complete reduction reaction, including a dramatic decrease in reaction rate at high solid conversions. Feeding syngas (p H2 = p CO = 0.1 bar) resulted in 1.1% carbon deposition of the feed. Steam was proven to be more effective in reducing carbon deposition than CO 2 . Moreover, it has been found that CuO/Al 2 O 3 catalyzed the water gas shift reaction and the reaction rate was not permanently affected by exposure to H 2 S, two key factors for CLC operation. The results of this work imply that CuO/Al 2 O 3 is an effective oxygen carrier as the first packed bed reactor in a TSCLC process and that the developed model is able to describe the performance at larger scales accurately

  4. Numerical modeling of pyrolysis of sawdust in a packed bed

    Energy Technology Data Exchange (ETDEWEB)

    Meng, Qingmin; Chen, Xiaoping [Southeast Univ., Nanjing (China). School of Energy and Environment

    2013-07-01

    An unsteady, one-dimensional mathematical model has been developed to describe the pyrolysis of sawdust in a packed bed. The sawdust bed was pyrolyzed using the hot gas and an electric heater outside the bed as the source of energy. The developed model includes mass, momentum and energy conservations of gas and solid within the bed. The gas flow in the bed is modeled using Darcy's law for fluid through a porous medium. The heat transfer model includes heat conduction inside the bed and convection between the bed and the hot gas. The kinetic model consists of primary pyrolysis reaction. A finite volume fully implicit scheme is employed for solving the heat and mass transfer model equations. A Runge-Kutta fourth order method is used for the chemical kinetics model equations. The model predictions of mass loss history and temperature were validated with published experimental results, showing a good agreement. The effects of inlet temperature on the pyrolysis process have been analyzed with model simulation. A sensitivity analysis using the model suggests that the predictions could be improved by considering the second reaction which could generate volatile flowing in the void.

  5. Magnetohydraulic flow through a packed bed of electrically conducting spheres

    International Nuclear Information System (INIS)

    Sanders, T.L.

    1985-01-01

    The flow of an electrically conducting fluid through a packed bed of electrically conducting spheres in the presence of a strong magnetic field constitutes a very complex flow situation due to the constant turning of the fluid in and out of magnetic field lines. The interaction of the orthogonal components of the velocity and magnetic field will induce electric fields that are orthogonal to both and the electric fields in turn can cause currents that interact with the magnetic field to generate forces against the direction of flow. The strengths of these generated forces depend primarily upon the closure paths taken by the induced currents which, in turn, depend upon the relative ratio of the electrical resistance of the solid spheres to that of the fluid. Both experimental and analytical analyses of the slow flow of a eutectic mixture of sodium and potassium (NaK) through packed cylinders containing stainless steel spheres in the presence of a strong transverse magnetic field were completed. A theory of magnetohydraulic flow is developed by analogy with the development of hydraulic radius theories of flow through porous media. An exact regional analysis is successfully applied to an infinite bed of electrically conducting spheres with a conducting or non-conducting constraining wall on one side. The equations derived are solved for many different combinations of flowrate, magnetic field strength, porosity, and electrical resistance ratio

  6. Biotransformation of ferulic acid to vanillin in the packed bed-stirred fermentors.

    Science.gov (United States)

    Yan, Lei; Chen, Peng; Zhang, Shuang; Li, Suyue; Yan, Xiaojuan; Wang, Ningbo; Liang, Ning; Li, Hongyu

    2016-10-06

    We performed the biotransformation of ferulic acid to vanillin using Bacillus subtilis (B. subtilis) in the stirring packed-bed reactors filled with carbon fiber textiles (CFT). Scanning electron microscope (SEM), HPLC, qRT-PCR and ATP assay indicated that vanillin biotransformation is tightly related to cell growth, cellar activity and the extent of biofilm formation. The biotransformation was affected by hydraulic retention time (HRT), temperature, initial pH, stirring speed and ferulic acid concentration, and the maximum vanillin production was obtained at 20 h, 35 °C, 9.0, 200 rpm, 1.5 g/L, respectively. Repeated batch biotransformation performed under this optimized condition showed that the maximum productivity (0.047 g/L/h) and molar yield (60.43%) achieved in immobilized cell system were 1.84 and 3.61 folds higher than those achieved in free cell system. Therefore, the stirring reactor packed with CFT carrier biofilm formed by B. subtilis represented a valid biocatalytic system for the production of vanillin.

  7. 3D Numerical Study of Multiphase Counter-Current Flow within a Packed Bed for Post Combustion Carbon Dioxide Capture

    Directory of Open Access Journals (Sweden)

    Li Yang

    2018-06-01

    Full Text Available The hydrodynamics within counter-current flow packed beds is of vital importance to provide insight into the design and operational parameters that may impact reactor and reaction efficiencies in processes used for post combustion CO2 capture. However, the multiphase counter-current flows in random packing used in these processes are complicated to visualize. Hence, this work aimed at developing a computational fluid dynamics (CFD model to study more precisely the complex details of flow inside a packed bed. The simulation results clearly demonstrated the development of, and changes in, liquid distributions, wetted areas, and film thickness under various gas and liquid flow rates. An increase in values of the We number led to a more uniform liquid distribution, and the flow patterns changed from droplet flow to film flow and trickle flow as the We number was increased. In contrast, an increase in gas flow rate had no significant effect on the wetted areas and liquid holdup. It was also determined that the number of liquid inlets affected flow behavior, and the liquid surface tension had an insignificant influence on pressure drop or liquid holdup; however, lower surface tension provided a larger wetted area and a thinner film. An experimental study, performed to enable comparisons between experimentally measured pressure drops and simulation-determined pressure drops, showed close correspondence and similar trends between the experimental data and the simulation data; hence, it was concluded that the simulation model was validated and could reasonably predict flow dynamics within a counter-current flow packed bed.

  8. A parametric study of powder holdups in a packed bed under ...

    African Journals Online (AJOL)

    Nafiisah

    Packed bed, turbulent flow, mathematical modelling, decreasing ..... The vertical gauge pressure distribution, at a distance of 0.06 m away from the tuyere ... fines from these locations as the interactive forces are more than the drag forces. It.

  9. Pt-catalyzed ozonation of aqueous phenol solution using high-gravity rotating packed bed

    International Nuclear Information System (INIS)

    Chang, Chia-Chi; Chiu, Chun-Yu; Chang, Ching-Yuan; Chang, Chiung-Fen; Chen, Yi-Hung; Ji, Dar-Ren; Tseng, Jyi-Yeong; Yu, Yue-Hwa

    2009-01-01

    In this study, a high-gravity rotating packed bed (HGRPB or HG) was used as a catalytic ozonation (Cat-OZ) reactor to decompose phenol. The operation of HGRPB system was carried out in a semi-batch apparatus which combines two major parts, namely the rotating packed bed (RPB) and photo-reactor (PR). The high rotating speed of RPB can give a high volumetric gas-liquid mass transfer coefficient with one or two orders of magnitude higher than those in the conventional packed beds. The platinum-containing catalyst (Dash 220N, Pt/γ-Al 2 O 3 ) and activated alumina (γ-Al 2 O 3 ) were packed in the RPB respectively to adsorb molecular ozone and the target pollutant of phenol on the surface to catalyze the oxidation of phenol. An ultra violet (UV) lamp (applicable wavelength λ = 200-280 nm) was installed in the PR to enhance the self-decomposition of molecular ozone in water to form high reactive radical species. Different combinations of advanced oxidation processes (AOPs) with the HGRPB for the degradation of phenol were tested. These included high-gravity OZ (HG-OZ), HG catalytic OZ (HG-Cat-OZ), HG photolysis OZ (HG-UV-OZ) and HG-Cat-OZ with UV (HG-Cat-UV-OZ). The decomposition efficiency of total organic compound (η TOC ) of HG-UV-OZ with power of UV (P UV ) of 16 W is 54% at applied dosage of ozone per volume sample m A,in = 1200 mg L -1 (reaction time t = 20 min), while that of HG-OZ without the UV irradiation is 24%. After 80 min oxidation (m A,in = 4800 mg L -1 ), the η TOC of HG-UV-OZ is as high as 94% compared to 82% of HG-OZ process. The values of η TOC for HG-Cat-OZ process with m S = 42 g are 56% and 87% at m A,in = 1200 and 4800 mg L -1 , respectively. By increasing the catalyst mass to 77 g, the η TOC for the HG-Cat-OZ process reaches 71% and 90% at m A,in = 1200 and 4800 mg L -1 , respectively. The introduction of Pt/γ-Al 2 O 3 as well as UV irradiation in the HG-OZ process can enhance the η TOC of phenol significantly, while γ-Al 2 O 3 exhibits

  10. Development of a novel integrated continuous reactor system for biocatalytic production of biodiesel.

    Science.gov (United States)

    Chattopadhyay, Soham; Sen, Ramkrishna

    2013-11-01

    A novel integrated immobilized enzyme-reactor system involving a continuous stirred tank reactor with two packed bed reactors in series was developed for the continuous production of biodiesel. The problem of methanol solubility into oil was solved by introducing a stirred tank reactor to dissolve methanol into partially converted oil. This step made the process perfectly continuous without requiring any organic solvent and intermittent methanol addition in the process. The substrate feeding rate of 0.74 mL/min and enzyme loading of 0.75 g per reactor were determined to be optimum for maximum biodiesel yield. The integrated continuous process was stable up to 45 cycles with biodiesel productivity of 137.2 g/L/h, which was approximately 5 times higher than solvent free batch process. In comparison with the processes reported in literature using expensive Novozyme 435 and hazardous organic solvent, the present process is completely green and perfectly continuous with economic and environmental advantages. Copyright © 2013 Elsevier Ltd. All rights reserved.

  11. Combined photolysis and catalytic ozonation of dimethyl phthalate in a high-gravity rotating packed bed

    Energy Technology Data Exchange (ETDEWEB)

    Chang, C.-C. [Graduate Institute of Environmental Engineering, National Taiwan University, Taipei 106, Taiwan (China); Chiu, C.-Y. [Department of Cosmetic Science and Application, Lan-Yang Institute of Technology, I-Lan 261, Taiwan (China); Chang, C.-Y. [Graduate Institute of Environmental Engineering, National Taiwan University, Taipei 106, Taiwan (China)], E-mail: cychang3@ntu.edu.tw; Chang, C.-F. [Department of Environmental Science and Engineering, Tunghai University, Taichung 407, Taiwan (China); Chen, Y.-H. [Department of Chemical and Material Engineering, National Kaohsiung University of Applied Science, Kaohsiung City 807, Taiwan (China); Ji, D.-R.; Yu, Y.-H.; Chiang, P.-C. [Graduate Institute of Environmental Engineering, National Taiwan University, Taipei 106, Taiwan (China)

    2009-01-15

    In this study, a high-gravity rotating packed bed (HGRPB) was used as a catalytic ozonation reactor to decompose dimethyl phthalate (DMP), an endocrine disrupting chemical commonly encountered. The HGRPB is an effective gas-liquid mixing equipment which can enhance the ozone mass transfer coefficient. Platinum-containing catalyst (Pt/-Al{sub 2}O{sub 3}) of Dash 220N and ultra violet (UV) lamp were combined in the high-gravity ozonation (HG-OZ) system to enhance the self-decomposition of molecular ozone in liquid to form highly reactive radical species. Different combinations of HG-OZ with Dash 220N and UV for the degradation of DMP were tested. These include HG-OZ, HG catalytic OZ (HG-Pt-OZ), HG photolysis OZ (HG-UV-OZ) and HG-UV-Pt-OZ. The result indicated that all the above four ozonation processes result in significant decomposition of DMP and mineralization of total organic carbon (TOC) at the applied ozone dosage per volume of liquid sample of 1.2 g L{sup -1}. The UV and Pt/{gamma}-Al{sub 2}O{sub 3} combined in HG-OZ can enhance the TOC mineralization efficiency ({eta}{sub TOC}) to 56% (via HG-UV-OZ) and 57% (via HG-Pt-OZ), respectively, while only 45% with ozone only. The process of HG-UV-Pt-OZ offers the highest {eta}{sub TOC} of about 68%.

  12. Optimization of tannase production by Aspergillus niger in solid-state packed-bed bioreactor.

    Science.gov (United States)

    Rodríguez-Durán, Luis V; Contreras-Esquivel, Juan C; Rodríguez, Raúl; Prado-Barragán, L Arely; Aguilar, Cristóbal N

    2011-09-01

    Tannin acyl hydrolase, also known as tannase, is an enzyme with important applications in the food, feed, pharmaceutical, and chemical industries. However, despite a growing interest in the catalytic properties of tannase, its practical use is very limited owing to high production costs. Several studies have already demonstrated the advantages of solid-state fermentation (SSF) for the production of fungal tannase, yet the optimal conditions for enzyme production strongly depend on the microbial strain utilized. Therefore, the aim of this study was to improve the tannase production by a locally isolated A. niger strain in an SSF system. The SSF was carried out in packed-bed bioreactors using polyurethane foam as an inert support impregnated with defined culture media. The process parameters influencing the enzyme production were identified using a Plackett–Burman design, where the substrate concentration, initial pH, and incubation temperature were determined as the most significant. These parameters were then further optimized using a Box-Behnken design. The maximum tannase production was obtained with a high tannic acid concentration (50 g/l), relatively low incubation temperature (30°C), and unique low initial pH (4.0). The statistical strategy aided in increasing the enzyme activity nearly 1.97-fold, from 4,030 to 7,955 U/l. Consequently, these findings can lead to the development of a fermentation system that is able to produce large amounts of tannase in economical, compact, and scalable reactors.

  13. Endoglucanase production with the newly isolated Myceliophtora sp. i-1d3b in a packed bed solid state fermentor

    Directory of Open Access Journals (Sweden)

    A. I. Zanelato

    2012-12-01

    Full Text Available This work is aimed to produce endoglucanase through solid state fermentation in a packed bed bioreactor with the use of the fungus Myceliophtora sp. I-1D3busing a mixture of wheat bran (WB and sugar cane bagasse (SCB as culture medium. Preliminary tests were performed in polypropylene plastic bags, controlling the variables temperature (40, 45, and 50ºC, initial moisture content (75, 80, and 85%, w.b., and weight proportion SCB/WB (1:1, 7:3, and 9:1. The highest enzyme activities in plastic bags were obtained using the substrate proportion of 7:3, 50ºC temperature, and 80% initial moisture content (878 U/grams of dry solid. High activities of filter-paper cellulase and xylanase were also obtained in plastic bags and some results are reported. For the packed bed experiments, the temperature (45 and 50ºC and the air flow rate (80, 100 and 120L/h were the controlled variables. Activity of endoglucanase was similar to plastic bag tests. A longitudinal gradient of moisture content, was observed increasing from the bottom to the top of the reactor, even though the longitudinal enzyme activity profile was flat for almost the whole bed. Air flow rate did not affect enzyme activity, while experiments carried out at 50ºC showed higher enzyme activities. The maximum temperature peak observed was at about 6ºC above the process temperature.

  14. A feasible enzymatic process for D-tagatose production by an immobilized thermostable L-arabinose isomerase in a packed-bed bioreactor.

    Science.gov (United States)

    Kim, Hye-Jung; Ryu, Se-Ah; Kim, Pil; Oh, Deok-Kun

    2003-01-01

    To develop a feasible enzymatic process for d-tagatose production, a thermostable l-arabinose isomerase, Gali152, was immobilized in alginate, and the galactose isomerization reaction conditions were optimized. The pH and temperature for the maximal galactose isomerization reaction were pH 8.0 and 65 degrees C in the immobilized enzyme system and pH 7.5 and 60 degrees C in the free enzyme system. The presence of manganese ion enhanced galactose isomerization to tagatose in both the free and immobilized enzyme systems. The immobilized enzyme was more stable than the free enzyme at the same pH and temperature. Under stable conditions of pH 8.0 and 60 degrees C, the immobilized enzyme produced 58 g/L of tagatose from 100 g/L galactose in 90 h by batch reaction, whereas the free enzyme produced 37 g/L tagatose due to its lower stability. A packed-bed bioreactor with immobilized Gali152 in alginate beads produced 50 g/L tagatose from 100 g/L galactose in 168 h, with a productivity of 13.3 (g of tagatose)/(L-reactor.h) in continuous mode. The bioreactor produced 230 g/L tagatose from 500 g/L galactose in continuous recycling mode, with a productivity of 9.6 g/(L.h) and a conversion yield of 46%.

  15. Biosorption of copper by marine algae Gelidium and algal composite material in a packed bed column.

    Science.gov (United States)

    Vilar, Vítor J P; Botelho, Cidália M S; Loureiro, José M; Boaventura, Rui A R

    2008-09-01

    Marine algae Gelidium and algal composite material were investigated for the continuous removal of Cu(II) from aqueous solution in a packed bed column. The biosorption behaviour was studied during one sorption-desorption cycle of Cu(II) in the flow through column fed with 50 and 25 mg l(-1) of Cu(II) in aqueous solution, at pH 5.3, leading to a maximum uptake capacity of approximately 13 and 3 mg g(-1), respectively, for algae Gelidium and composite material. The breakthrough time decreases as the inlet copper concentration increases, for the same flow rate. The pH of the effluent decreases over the breakthrough time of copper ions, which indicates that ion exchange is one of the mechanisms involved in the biosorption process. Temperature has little influence on the metal uptake capacity and the increase of the ionic strength reduces the sorption capacity, decreasing the breakthrough time. Desorption using 0.1M HNO(3) solution was 100% effective. After two consecutive sorption-desorption cycles no changes in the uptake capacity of the composite material were observed. A mass transfer model including film and intraparticle resistances, and the equilibrium relationship, for adsorption and desorption, was successfully applied for the simulation of the biosorption column performance.

  16. Hexavalent chromium reduction in a sulfur reducing packed-bed bioreactor

    Energy Technology Data Exchange (ETDEWEB)

    Sahinkaya, Erkan, E-mail: erkansahinkaya@yahoo.com [Department of Bioengineering, Istanbul Medeniyet University, Goeztepe, Istanbul (Turkey); Kilic, Adem [Department of Environmental Engineering, Harran University, Osmanbey Campus, 63000 Sanliurfa (Turkey); Altun, Muslum [Department of Chemistry, Hacettepe University, Beytepe, Ankara (Turkey); Komnitsas, Kostas [Department of Mineral Resources Engineering, Technical University of Crete, 73100 Chania (Greece); Lens, Piet N.L. [Unesco-IHE Institute for Water Education, Westvest 7, Delft 2611 AX (Netherlands)

    2012-06-15

    Highlights: Black-Right-Pointing-Pointer Elemental sulfur can be used as electron acceptor for sulfide production. Black-Right-Pointing-Pointer Biogenically produced sulfide reduces Cr(VI) to the much less toxic and immobile form of Cr(III). Black-Right-Pointing-Pointer Sulfur packed bioreactor is efficient for Cr(VI) containing wastewater treatment. Black-Right-Pointing-Pointer Reduced form of chromium precipitates in the bioreactor. - Abstract: The most commonly used approach for the detoxification of hazardous industrial effluents and wastewaters containing Cr(VI) is its reduction to the much less toxic and immobile form of Cr(III). This study investigates the cleanup of Cr(VI) containing wastewaters using elemental sulfur as electron acceptor, for the production of hydrogen sulfide that induces Cr(VI) reduction. An elemental sulfur reducing packed-bed bioreactor was operated at 28-30 Degree-Sign C for more than 250 days under varying influent Cr(VI) concentrations (5.0-50.0 mg/L) and hydraulic retention times (HRTs, 0.36-1.0 day). Ethanol or acetate (1000 mg/L COD) was used as carbon source and electron donor. The degree of COD oxidation varied between 30% and 85%, depending on the operating conditions and the type of organic carbon source. The oxidation of organic matter was coupled with the production of hydrogen sulfide, which reached a maximum concentration of 750 mg/L. The biologically produced hydrogen sulfide reduced Cr(VI) chemically to Cr(III) that precipitated in the reactor. Reduction of Cr(VI) and removal efficiency of total chromium always exceeded 97% and 85%, respectively, implying that the reduced chromium was retained in the bioreactor. This study showed that sulfur can be used as an electron acceptor to produce hydrogen sulfide that induces efficient reduction and immobilization of Cr(VI), thus enabling decontamination of Cr(VI) polluted wastewaters.

  17. Accelerated carbonation of steelmaking slags in a high-gravity rotating packed bed

    International Nuclear Information System (INIS)

    Chang, E-E; Pan, Shu-Yuan; Chen, Yi-Hung; Tan, Chung-Sung; Chiang, Pen-Chi

    2012-01-01

    Highlights: ► The carbonation conversion in a RPB was higher than that in traditional reactors. ► The optimum conditions were operated at 750 rpm and 65 °C for 30 min. ► The product on BOF slag was identified as crystallized calcite based on SEM and XRD. ► The diffusivity ranged from 10 −7 to 10 −6 cm 2 s −1 based on the shrinking core model. - Abstract: Carbon dioxide (CO 2 ) sequestration using the accelerated carbonation of basic oxygen furnace (BOF) slag in a high-gravity rotating packed bed (RPB) under various operational conditions was investigated. The effects of reaction time, reaction temperature, rotation speed and slurry flow rate on the CO 2 sequestration process were evaluated. The samples of reacted slurry were analyzed quantitatively using thermogravimetric analysis (TGA) and atomic absorption spectrometry (AAS) and qualitatively using X-ray diffraction (XRD), scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDX), and transmission electron microscopy (TEM). The sequestration experiments were performed at a liquid-to-solid ratio of 20:1 with a flow rate of 2.5 L min −1 of a pure CO 2 stream under atmospheric temperature and pressure. The results show that a maximum conversion of BOF slag was 93.5% at a reaction time of 30 min and a rotation speed of 750 rpm at 65 °C. The experimental data were utilized to determine the rate-limiting mechanism based on the shrinking core model (SCM), which was validated by the observations of SEM and TEM. Accelerated carbonation in a RPB was confirmed to be a viable method due to its higher mass-transfer rate.

  18. Preliminary performance analysis of a transverse flow spectrally selective two-slab packed bed volumetric receiver

    CSIR Research Space (South Africa)

    Roos, TH

    2016-05-01

    Full Text Available for the transparent slab 1 and SiC for the opaque slab 2 – which are ordered in a hexagonally close-packed bed. The flow direction has been changed from parallel to the incident radiation and perpendicular to the window, to parallel to the window and perpendicular...

  19. A parametric study pf powder holdups in a packed bed under ...

    African Journals Online (AJOL)

    More specifically, a parametric study is performed to determine the effects of the gas blast velocity, particle size adn powder loading on the powder holdups. Results are presented in terms of fines accumulation area. This work shows the dependency of the powder holdups on the packed bed flow parameters. Keywords: ...

  20. Kinetic model for an up-flow anaerobic packed bed bioreactor: Dairy ...

    African Journals Online (AJOL)

    Kinetic studies of anaerobic digestion process of cheese whey were conducted in a pilot-scale up-flow anaerobic packed bed bioreactor (UAPB). An influent COD concentration of 59419 mg/l was utilized at steady state condition. Logistic and Monod kinetic models were employed to describe microbial activities of cheese ...

  1. Experimental investigation into a packed bed thermal storage solution for solar gas turbine systems

    CSIR Research Space (South Africa)

    Klein, P

    2013-09-01

    Full Text Available High temperature thermal storage in randomly packed beds of ceramic particles is proposed as an effective storage solution for Solar Gas Turbine (SGT) cycles in the near term. Numerical modelling of these systems allows for optimised thermal storage...

  2. Analysis of wall-packed-bed thermal interactions

    International Nuclear Information System (INIS)

    Gorbis, Z.R.; Tillack, M.S.; Tehranian, F.; Abdou, M.A.

    1995-01-01

    One of the major issues remaining for ceramic breeder blankets involves uncertainties in heat transfer and thermomechanical interactions within the breeder and multiplier regions. Particle bed forms are considered in many reactor blanket designs for both the breeder and Be multiplier. The effective thermal conductivity of beds and the wall-bed thermal conductance are still not adequately characterized, particularly under the influence of mechanical stresses. The problem is particularly serious for the wall conductance between Be and its cladding, where the uncertainty can be greater than 50%. In this work, we describe a new model for the wall-bed conductance that treats the near-wall region as a finite-width zone. The model includes an estimate of the region porosity based on the number of contact points, and the contact area for smooth surfaces. It solves the heat conduction in a near-wall unit cell. The model is verified with existing data and used to predict the range of wall conductances expected in future simulation experiments and in reactor applications. (orig.)

  3. Freezing process in unsaturated packed beds; Fuhowa ryushi sonai ni okeru suibun toketsu

    Energy Technology Data Exchange (ETDEWEB)

    Akahori, M; Aoki, K; Hattori, M [Nagaoka University of Technology, Niigata (Japan); Tani, T [Oji Paper Co. Ltd., Tokyo (Japan)

    1998-04-25

    The freezing process in unsaturated packed beds has been investigated experimentally and theoretically. Water transport to the frozen front plays an important part on freezing. The rate of the absorption of water into frozen layer depended on the freezing heat flux and the water saturation at the freezing front. As a result, ice content in the frozen layer was related to the rate of the absorption of water and the freezing heat flux. A one-dimensional freezing model in unsaturated packed beds has been presented, accounting for the water transport. The predicted water saturation and temperature distributions in the body and the thickness of frozen layer were compared with the experimental results using a porous bed composed of glass beads. 12 refs., 10 figs., 1 tab.

  4. The Dynamic Behavior of Water Flowing Through Packed Bed of Different Particle Shapes and Sizes

    Directory of Open Access Journals (Sweden)

    Haneen Ahmed Jasim

    2017-12-01

    Full Text Available An experimental study was conducted on pressure drop of water flow through vertical cylindrical packed beds in turbulent region and the influence of the operating parameters on its behavior. The bed packing was made of spherical and non-spherical particles (spheres, Rasching rings and intalox saddle with aspect ratio range 3.46 D/dp 8.486 obtaining bed porosities 0.396 0.84 and Reynolds number 1217 21758. The system is consisted of 5 cm inside diameter Perspex column, 50 cm long; distilled water was pumped through the bed with flow rate 875, 1000, 1125, 1250,1375 and 1500 l/h and inlet water temperature 20, 30, 40 and 50 ˚C. The packed bed system was monitored by using LabVIEW program, were the results have been obtained from Data Acquisition Adaptor (DAQ.

  5. The behavior of xenon dynamic adsorption on granular activated carbon packed bed adsorber

    International Nuclear Information System (INIS)

    Chongyang Zhou; Shujuan Feng; Guoqing Zhou; Yuren Jin; Junfu Liang; Jingming Xu

    2011-01-01

    In order to retard radioxenon release into the atmosphere from nuclear power station or to sensitively monitor its concentration to ensure environmental and human safety, it is necessary to know the behavior of xenon dynamic adsorption on granular activated carbon pack bed adsorber. The quantities, including the dynamic adsorption coefficient (k d ), the amount of xenon adsorbed (q), the length of mass transfer zone (L MTZ ) and the length of the unused bed (LUB), used to describe the adsorption behavior, were sorted out and calculated. The factors, including xenon concentrations, pressures and temperatures, to affect these quantities were investigated. The results show that: (1) The values of k d and q decrease with increasing temperatures, but increase with increasing pressures, (2) The values of L MTZ and LUB increase with increasing temperatures or pressures, but are independent of concentrations. Knowledge of these quantities is very helpful for packed bed adsorber operation. (author)

  6. Process for the exchange of hydrogen isotopes using a catalyst packed bed assembly

    International Nuclear Information System (INIS)

    Butler, J.P.; den Hartog, J.; Molson, F.W.R.

    1978-01-01

    A process for the exchange of hydrogen isotopes between streams of gaseous hydrogen and liquid water is described, wherein the streams of liquid water and gaseous hydrogen are simultaneously brought into contact with one another and a catalyst packed bed assembly while at a temperature in the range 273 0 to 573 0 K. The catalyst packed bed assembly may be composed of discrete carrier bodies of e.g. ceramics, metals, fibrous materials or synthetic plastics with catalytically active metal crystallites selected from Group VIII of the Periodic Table, partially enclosed in and bonded to the carrier bodies by a water repellent, water vapor and hydrogen gas permeable, porous, polymeric material, and discrete packing bodies having an exterior surface which is substantially hydrophilic and relatively noncatalytically active with regard to hydrogen isotope exchange between hydrogen gas and water vapor to that of the catalyst bodies

  7. A catalytic reactor for the organocatalyzed enantioselective continuous flow alkylation of aldehydes.

    Science.gov (United States)

    Porta, Riccardo; Benaglia, Maurizio; Puglisi, Alessandra; Mandoli, Alessandro; Gualandi, Andrea; Cozzi, Pier Giorgio

    2014-12-01

    The use of immobilized metal-free catalysts offers the unique possibility to develop sustainable processes in flow mode. The challenging intermolecular organocatalyzed enantioselective alkylation of aldehydes was performed for the first time under continuous flow conditions. By using a packed-bed reactor filled with readily available supported enantiopure imidazolidinone, different aldehydes were treated with three distinct cationic electrophiles. In the organocatalyzed α-alkylation of aldehydes with 1,3-benzodithiolylium tetrafluoroborate, excellent enantioselectivities, in some cases even better than those obtained in the flask process (up to 95% ee at 25 °C), and high productivity (more than 3800 h(-1) ) were obtained, which thus shows that a catalytic reactor may continuously produce enantiomerically enriched compounds. Treatment of the alkylated products with Raney-nickel furnished enantiomerically enriched α-methyl derivatives, key intermediates for active pharmaceutical ingredients and natural products. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. continuous stirred tank reactor (CSTR)

    African Journals Online (AJOL)

    AFRICAN JOURNALS ONLINE (AJOL) · Journals · Advanced Search ... stirred tank reactor (CSTR) and the small and large intestines as plug flow reactor (PFR) ... from the two equations are used for the reactor sizing of the modeled reactors.

  9. Oxidation of tritium in packed bed of noble metal catalyst for detritiation from system gases

    International Nuclear Information System (INIS)

    Nishikawa, Masabumi; Takeishi, Toshiharu; Munakata, Kenzo; Kotoh, Kenji; Enoeda, Mikio

    1985-01-01

    Catalytic oxidation rates of tritium in the bed of the noble metal catalysts are obtained and compared with the oxidation rates observed for the packed bed of spongy copper oxide or hopcalites. Use of Pt- or Pd-aluminia catalysts is recommended in this study because they give effective oxidation rates of tritium in the ambient temperature range. The adsorption performance of tritiated water in the catalyst bed is also discussed. (orig.)

  10. Pressure drop in packed beds of spherical particles at ambient and elevated air temperatures

    Directory of Open Access Journals (Sweden)

    Pešić Radojica

    2015-01-01

    Full Text Available The aim of this work was the experimental investigation of the particle friction factor for air flow through packed bed of particles at ambient and elevated temperatures. The experiments were performed by measuring the pressure drop across the packed bed, heated to the desired temperature by hot air. Glass spherical particles of seven different diameters were used. The temperature range of the air flowing through the packed bed was from 20ºC to 350ºC and the bed voidages were from 0.3574 to 0.4303. The obtained results were correlated using a number of available literature correlations. The overall best fit of all of the experimental data was obtained using Ergun [1] equation, with mean absolute deviation of 10.90%. Ergun`s equation gave somewhat better results in correlating the data at ambient temperature with mean absolute deviation of 9.77%, while correlation of the data at elevated temperatures gave mean absolute deviation of 12.38%. The vast majority of the correlations used gave better results when applied to ambient temperature data than to the data at elevated temperatures. Based on the results obtained, Ergun [1] equation is proposed for friction factor calculation both at ambient and at elevated temperatures. [Projekat Ministarstva nauke Republike Srbije, br. ON172022

  11. Volatile Removal Assembly Flight Experiment and KC-135 Packed Bed Experiment: Results and Lessons Learned

    Science.gov (United States)

    Holder, Donald W.; Parker, David

    2000-01-01

    The Volatile Removal Assembly (VRA) is a high temperature catalytic oxidation process that will be used as the final treatment for recycled water aboard the International Space Station (ISS). The multiphase nature of the process had raised concerns as to the performance of the VRA in a microgravity environment. To address these concerns, two experiments were designed. The VRA Flight Experiment (VRAFE) was designed to test a full size VRA under controlled conditions in microgravity aboard the SPACEHAB module and in a 1 -g environment and compare the performance results. The second experiment relied on visualization of two-phase flow through small column packed beds and was designed to fly aboard NASA's microgravity test bed plane (KC-135). The objective of the KC-135 experiment was to understand the two-phase fluid flow distribution in a packed bed in microgravity. On Space Transportation System (STS) flight 96 (May 1999), the VRA FE was successfully operated and in June 1999 the KC-135 packed bed testing was completed. This paper provides an overview of the experiments and a summary of the results and findings.

  12. A mathematical model for supplying air-cooling for a building using a packed bed

    Energy Technology Data Exchange (ETDEWEB)

    Marewo, G.T. [Zimbabwe Univ., Mathematics Dept., Harare (Zimbabwe); Henwood, D.J. [School of Computing and Mathematical Sciences, Brighton (United Kingdom)

    2006-01-15

    The cooling system at the Harare International School uses a packed bed system for storing the coldness of the night-time to be used later for day-time air-conditioning. A two-phase mathematical model is described for the packed bed which includes heat dispersion in the fluid, and heat loss to the environment. This is in contrast to other studies, where at least one of these terms is neglected to simplify the mathematical model. A numerical method for obtaining a solution is proposed and implemented. Using measured inlet temperatures, the measured and predicted outlet temperatures of the bed show good trend agreement. The differences in detail are examined through sensitivity analyses for both the heat convection transfer and air velocity. It is apparent that adjusting these parameters can increase the agreement between the predicted and measured data. A parametric study for heat storage with various materials and bed sizes is given, which indicates how the code may be used as a tool for improving design and operational parameters. Practical application: A mathematical model of a packed bed is described; the bed is made up of fluid flowing over solid material with heat interchange between the two. The solid material is idealized as spheres and the fluid temperature is assumed uniform in a cross-section of the bed. The model includes heat interchange between the bed and its surrounding environment and allows for time varying fluid velocity. The input data is the inlet temperature to the bed, which may be measured. The comparison with measured data may be helpful to anyone attempting to develop and test a similar model. The sensitivity tests give an understanding of the significance of some of the parameters involved. The Appendix gives a mathematical statement of the problem and an outline of an approach to developing computer code for a numerical solution. (Author)

  13. Hydrogen production from water gas shift reaction in a high gravity (Higee) environment using a rotating packed bed

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Wei-Hsin; Syu, Yu-Jhih [Department of Greenergy, National University of Tainan, Tainan 700 (China)

    2010-10-15

    Hydrogen production via the water gas shift reaction (WGSR) was investigated in a high gravity environment. A rotating packed bed (RPB) reactor containing a Cu-Zn catalyst and spinning in the range of 0-1800 rpm was used to create high centrifugal force. The reaction temperature and the steam/CO ratio ranged from 250 to 350 C and 2 to 8, respectively. A dimensionless parameter, the G number, was derived to account for the effect of centrifugal force on the enhancement of the WGSR. With the rotor speed of 1800 rpm, the induced centrifugal force acting on the reactants was as high as 234 g on average in the RPB. As a result, the CO conversion from the WGSR was increased up to 70% compared to that without rotation. This clearly revealed that the centrifugal force was conducive to hydrogen production, resulting from intensifying mass transfer and elongating the path of the reactants in the catalyst bed. From Le Chatelier's principle, a higher reaction temperature or a lower steam/CO ratio disfavors CO conversion; however, under such a situation the enhancement of the centrifugal force on hydrogen production from the WGSR tended to become more significant. Accordingly, a correlation between the enhancement of CO conversion and the G number was established. As a whole, the higher the reaction temperature and the lower the steam/CO ratio, the higher the exponent of the G number function and the better the centrifugal force on the WGSR. (author)

  14. Special topics reports for the reference tandem mirror fusion breeder: liquid metal MHD pressure drop effects in the packed bed blanket. Vol. 1

    International Nuclear Information System (INIS)

    McCarville, T.J.; Berwald, D.H.; Wong, C.P.C.

    1984-09-01

    Magnetohydrodynamic (MHD) effects which result from the use of liquid metal coolants in magnetic fusion reactors include the modification of flow profiles (including the suppression of turbulence) and increases in the primary loop pressure drop and the hydrostatic pressure at the first wall of the blanket. In the reference fission-suppressed tandem mirror fusion breeder design concept, flow profile modification is a relatively minor concern, but the MHD pressure drop in flowing the liquid lithium coolant through an annular packed bed of beryllium/thorium pebbles is directly related to the required first wall structure thickness. As such, it is a major concern which directly impacts fissile breeding efficiency. Consequently, an improved model for the packed bed pressure drop has been developed. By considering spacial averages of electric fields, currents, and fluid flow velocities the general equations have been reduced to simple expressions for the pressure drop. The averaging approach results in expressions for the pressure drop involving a constant which reflects details of the flow around the pebbles. Such details are difficult to assess analytically, and the constant may eventually have to be evaluated by experiment. However, an energy approach has been used in this study to bound the possible values of the constant, and thus the pressure drop. In anticipation that an experimental facility might be established to evaluate the undetermined constant as well as to address other uncertainties, a survey of existing facilities is presented

  15. Modelling and Simulation of a Packed Bed of Pulp Fibers Using Mixed Collocation Method

    Directory of Open Access Journals (Sweden)

    Ishfaq Ahmad Ganaie

    2013-01-01

    Full Text Available A convenient computational approach for solving mathematical model related to diffusion dispersion during flow through packed bed is presented. The algorithm is based on the mixed collocation method. The method is particularly useful for solving stiff system arising in chemical and process engineering. The convergence of the method is found to be of order 2 using the roots of shifted Chebyshev polynomial. Model is verified using the literature data. This method has provided a convenient check on the accuracy of the results for wide range of parameters, namely, Peclet numbers. Breakthrough curves are plotted to check the effect of Peclet number on average and exit solute concentrations.

  16. Friction factor for water flow through packed beds of spherical and non-spherical particles

    Directory of Open Access Journals (Sweden)

    Kaluđerović-Radoičić Tatjana

    2017-01-01

    Full Text Available The aim of this work was the experimental evaluation of different friction factor correlations for water flow through packed beds of spherical and non-spherical particles at ambient temperature. The experiments were performed by measuring the pressure drop across the bed. Packed beds made of monosized glass spherical particles of seven different diameters were used, as well as beds made of 16 fractions of quartz filtration sand obtained by sieving (polydisperse non-spherical particles. The range of bed voidages was 0.359–0.486, while the range of bed particle Reynolds numbers was from 0.3 to 286 for spherical particles and from 0.1 to 50 for non-spherical particles. The obtained results were compared using a number of available literature correlations. In order to improve the correlation results for spherical particles, a new simple equation was proposed in the form of Ergun’s equation, with modified coefficients. The new correlation had a mean absolute deviation between experimental and calculated values of pressure drop of 9.04%. For non-spherical quartz filtration sand particles the best fit was obtained using Ergun’s equation, with a mean absolute deviation of 10.36%. Surface-volume diameter (dSV necessary for correlating the data for filtration sand particles was calculated based on correlations for dV = f(dm and Ψ = f(dm. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. ON172022

  17. Performance of a desiccant assisted packed bed passive solar dryer for copra processing

    Directory of Open Access Journals (Sweden)

    Padmanaban Govindarajulu

    2017-01-01

    Full Text Available In this paper, the performance of a novel desiccant assisted packed bed passive solar dryer was evaluated for copra processing and compared with conventional passive solar dryer. This novel solar dryer consists of a desiccant assisted packed bed solar air heater attached with a dryer cabin. The desiccant and phase change materials packed in the solar air heater has control the humidity and retains the heat for longer duration, respectively. The performance of the dryer was evaluated (in terms of drying time to attain the final equilibrium moisture content, drying rate, specific moisture extraction rate, pick-up efficiency, and dryer efficiency under the meteorological conditions of Coimbatore city in India during March and April 2016. The copra was dried from initial moisture content (wet basis of about 52% to the final moisture content (wet basis of about 8% in 62 hours with specific moisture extraction rate of 0.82 kg/kWh. The drying time was reduced by about 44 hours when compared to the conventional passive solar dryer. The dryer pick-up efficiency was varied between about 10% and 65%. The average dryer thermal efficiency was calculated to be about 32%. The quality of final dried product was found to be good.

  18. Adsorption of zinc ions on bone char using helical coil-packed bed columns and its mass transfer modeling

    DEFF Research Database (Denmark)

    Moreno-Pérez, J.; Bonilla-Petriciolet, A.; Rojas-Mayorga, C. K.

    2016-01-01

    This study reports the assessment of helical coil-packed bed columns for Zn2+ adsorption on bone char. Zn2+ adsorption breakthrough curves have been obtained using helical coil columns with different characteristics and a comparison has been conducted with respect to the results of straight fixed-bed...... columns. Results showed that the helical coil adsorption columns may offer an equivalent removal performance than that obtained for the traditional packed bed columns but using a compact structure. However, the coil diameter, number of turns, and feed flow appear to be crucial parameters for obtaining...... the best performance in this packed-bed geometry. A mass transfer model for a mobile fluid flowing through a porous media was used for fitting and predicting the Zn2+ breakthrough curves in helical coil bed columns. Results of adsorbent physicochemical characterization showed that Zn2+ adsorption on bone...

  19. Experiments on forced convection form a horizontal heated plate in a packed bed of glass spheres

    Energy Technology Data Exchange (ETDEWEB)

    Renken, K.J. (Univ. of Wisconsin, Milwaukee (USA)); Poulikakos, D. (Univ. of Illinois, Chicago (USA))

    1989-02-01

    This paper presents an experimental investigation of boundary-layer forced convective heat transfer from a flat isothermal plate in a packed bed of spheres. Extensive experimental results are reported for the thermal boundary-layer thickness, the temperature field, and the local wall heat flux (represented by the local Nusselt number). Theoretical findings of previous investigations using the Darcy flow model as well as a general model for themomentum equation accouting for flow inertia and macroscopic shear wtih and without variable porosity are used to evaluate the theoretical models. Several trends are revealed regarding the conditions of validity of these flow models. Overall the general flow model including variable porosity appears to perform better, even through the need for serious improvements in modeling becomes apparent.

  20. Single and double pass solar air heaters with wire mesh as packing bed

    Energy Technology Data Exchange (ETDEWEB)

    Aldabbagh, L.B.Y.; Egelioglu, F. [Mechanical Engineering Department, Eastern Mediterranean University, Magosa, Mersin 10 (Turkey); Ilkan, M. [School of Computing and Tecnology, Eastern Mediterranean University, Magosa, Mersin 10 (Turkey)

    2010-09-15

    The thermal performances of single and double pass solar air heaters with steel wire mesh layers are used instead of a flat absorber plate are investigated experimentally. The effects of mass flow rate of air on the outlet temperature and thermal efficiency were studied. The results indicate that the efficiency increases with increasing the mass flow rate for the range of the flow rate used in this work between 0.012 and 0.038 kg/s. For the same flow rate, the efficiency of the double pass is found to be higher than the single pass by 34-45%. Moreover, the maximum efficiencies obtained for the single and the double pass air collectors are 45.93 and 83.65% respectively for the mass flow rate of 0.038 kg/s. Comparison of the results of a packed bed collector with those of a conventional collector shows a substantial enhancement in the thermal efficiency. (author)

  1. Electrochemical removal of copper ions from dilute solutions using packed bed electrode. Part І

    Directory of Open Access Journals (Sweden)

    I.A. Khattab

    2013-06-01

    Full Text Available Removal of some hazardous waste like copper from effluent streams has an industrial importance. In this field, this paper is directed towards electrochemical removal of copper ions from sulfate solution using packed bed electrode. The cathode packing is in static mode, consisted of graphite particles, with mean particle size equal to 0.125 cm. The high surface area of this cell is expected to give high current efficiency and removal percent. The effect of current density and liquid flow rate were tested. Experimental results obtained indicate that the efficiencies are in direct proportional with current density while inversely proportional with liquid flow rate. It was observed that, using this cell was effective in reducing copper concentration to less than 4 mg/l with R.E of 96.2% during 30 min electrolysis time.

  2. Treatment of Ni-EDTA containing wastewater by electrocoagulation using iron scraps packed-bed anode.

    Science.gov (United States)

    Ye, Xiaokun; Zhang, Junya; Zhang, Yan; Lv, Yuancai; Dou, Rongni; Wen, Shulong; Li, Lianghao; Chen, Yuancai; Hu, YongYou

    2016-12-01

    The unique electrocoagulator proposed in this study is highly efficient at removing Ni-EDTA, providing a potential remediation option for wastewater containing lower concentrations of Ni-EDTA (Ni ≤ 10 mg L -1 ). In the electrocoagulation (EC) system, cylindrical graphite was used as a cathode, and a packed-bed formed from iron scraps was used as an anode. The results showed that the removal of Ni-EDTA increased with the application of current and favoured acidic conditions. We also found that the iron scrap packed-bed anode was superior in its treatment ability and specific energy consumption (SECS) compared with the iron rod anode. In addition, the packed density and temperature had a large influence on the energy consumption (ECS). Over 94.3% of Ni and 95.8% of TOC were removed when conducting the EC treatment at an applied current of 0.5 A, initial pH of 3, air-purged rate 0.2 L min -1 , anode packed density of 400 kg m -3 temperature of 313 K and time of 30 min. SEM analysis of the iron scraps indicated that the specific area of the anode increased after the EC. The XRD analysis of flocs produced during EC revealed that hematite (α-Fe 2 O 3 ) and magnetite (Fe 3 O 4 ) were the main by-products under aerobic and anoxic conditions, respectively. A kinetic study demonstrated that the removal of Ni-EDTA followed a first-order model with the current parameters. Moreover, the removal efficiency of real wastewater was essentially consistent with that of synthetic wastewater. Copyright © 2016 Elsevier Ltd. All rights reserved.

  3. Thermo-mechanical parametric analysis of packed-bed thermocline energy storage tanks

    International Nuclear Information System (INIS)

    González, Ignacio; Pérez-Segarra, Carlos David; Lehmkuhl, Oriol; Torras, Santiago; Oliva, Assensi

    2016-01-01

    Highlights: • A numerical model of packed-bed thermocline thermal storage for CSP is presented. • Up-to-date commercial configurations are tested both thermally and structurally. • Promising thermal performance is obtained with a temperature difference of 100 °C. • Reliable factors of safety against material yielding and ratcheting can be obtained. • Cyclic relaxation-traction elastic wall stresses arise with plant normal operation. - Abstract: A packed-bed thermocline tank represents a proved cheaper thermal energy storage for concentrated solar power plants compared with the commonly-built two-tank system. However, its implementation has been stopped mainly due to the vessel’s thermal ratcheting concern, which would compromise its structural integrity. In order to have a better understanding of the commercial viability of thermocline approach, regarding energetic effectiveness and structural reliability, a new numerical simulation platform has been developed. The model dynamically solves and couples all the significant components of the subsystem, being able to evaluate its thermal and mechanical response over plant normal operation. The filler material is considered as a cohesionless bulk solid with thermal expansion. For the stresses on the tank wall the general thermoelastic theory is used. First, the numerical model is validated with the Solar One thermocline case, and then a parametric analysis is carried out by settling this storage technology in two real plants with a temperature rise of 100 °C and 275 °C. The numerical results show a better storage performance together with the lowest temperature difference, but both options achieve suitable structural factors of safety with a proper design.

  4. Experimental Study of the Flooding and Appearance of a Bubble Bed on Top of a Countercurrent Packed-Bed Column

    Czech Academy of Sciences Publication Activity Database

    Jiřičný, Vladimír; Staněk, Vladimír; Svoboda, Petr; Ondráček, Jakub

    2001-01-01

    Roč. 40, č. 1 (2001), s. 407-412 ISSN 0888-5885 R&D Projects: GA ČR GA203/97/1174 Institutional research plan: CEZ:AV0Z4072921 Keywords : appearance * bubble-bed * packed bed column Subject RIV: CI - Industrial Chemistry, Chemical Engineering Impact factor: 1.351, year: 2001

  5. Using crosslinkable diacetylene phospholipids to construct two-dimensional packed beds in supported lipid bilayer separation platforms

    Directory of Open Access Journals (Sweden)

    Shu-Kai Hu, Sheng-Wen Hsiao, Hsun-Yen Mao, Ya-Ming Chen, Yung Chang and Ling Chao

    2013-01-01

    Full Text Available Separating and purifying cell membrane-associated biomolecules has been a challenge owing to their amphiphilic property. Taking these species out of their native lipid membrane environment usually results in biomolecule degradation. One of the new directions is to use supported lipid bilayer (SLB platforms to separate the membrane species while they are protected in their native environment. Here we used a type of crosslinkable diacetylene phospholipids, diynePC (1,2-bis(10,12-tricosadiynoyl-sn-glycero-3-phosphocholine, as a packed material to create a 'two-dimensional (2D packed bed' in a SLB platform. After the diynePC SLB is exposed to UV light, some of the diynePC lipids in the SLB can crosslink and the non-crosslinked monomer lipids can be washed away, leaving a 2D porous solid matrix. We incorporated the lipid vesicle deposition method with a microfluidic device to pattern the location of the packed-bed region and the feed region with species to be separated in a SLB platform. Our atomic force microscopy result shows that the nano-scaled structure density of the '2D packed bed' can be tuned by the UV dose applied to the diynePC membrane. When the model membrane biomolecules were forced to transport through the packed-bed region, their concentration front velocities were found to decrease linearly with the UV dose, indicating the successful creation of packed obstacles in these 2D lipid membrane separation platforms.

  6. Mass balance and isotope effects during nitrogen transport through septic tank systems with packed-bed (sand) filters

    Science.gov (United States)

    Hinkle, S.R.; Böhlke, J.K.; Fisher, L.H.

    2008-01-01

    Septic tank systems are an important source of NO3- to many aquifers, yet characterization of N mass balance and isotope systematics following septic tank effluent discharge into unsaturated sediments has received limited attention. In this study, samples of septic tank effluent before and after transport through single-pass packed-bed filters (sand filters) were evaluated to elucidate mass balance and isotope effects associated with septic tank effluent discharge to unsaturated sediments. Chemical and isotopic data from five newly installed pairs and ten established pairs of septic tanks and packed-bed filters serving single homes in Oregon indicate that aqueous solute concentrations are affected by variations in recharge (precipitation, evapotranspiration), NH4+ sorption (primarily in immature systems), nitrification, and gaseous N loss via NH3 volatilization and(or) N2 or N2O release during nitrification/denitrification. Substantial NH4+ sorption capacity was also observed in laboratory columns with synthetic effluent. Septic tank effluent ??15N-NH4+ values were almost constant and averaged + 4.9??? ?? 0.4??? (1 ??). In contrast, ??15N values of NO3- leaving mature packed-bed filters were variable (+ 0.8 to + 14.4???) and averaged + 7.2??? ?? 2.6???. Net N loss in the two networks of packed-bed filters was indicated by average 10-30% decreases in Cl--normalized N concentrations and 2-3??? increases in ??15N, consistent with fractionation accompanying gaseous N losses and corroborating established links between septic tank effluent and NO3- in a local, shallow aquifer. Values of ??18O-NO3- leaving mature packed-bed filters ranged from - 10.2 to - 2.3??? (mean - 6.4??? ?? 1.8???), and were intermediate between a 2/3 H2O-O + 1/3 O2-O conceptualization and a 100% H2O-O conceptualization of ??18O-NO3- generation during nitrification.

  7. Treatment of ferrous-NTA-based NO x scrubber solution by an up-flow anaerobic packed bed bioreactor.

    Science.gov (United States)

    Chandrashekhar, B; Sahu, Nidhi; Tabassum, Heena; Pai, Padmaraj; Morone, Amruta; Pandey, R A

    2015-06-01

    A bench scale system consisting of an up-flow packed bed bioreactor (UAPBR) made of polyurethane foam was used for the treatment and regeneration of aqueous solution of ferrous-NTA scrubbed with nitric oxide (NO). The biomass in the UAPBR was sequentially acclimatized under denitrifying and iron reducing conditions using ethanol as electron donor, after which nitric oxide (NO) gas was loaded continuously to the system by absorption. The system was investigated for different parameters viz. pH, removal efficiency of nitric oxide, biological reduction efficiency of Fe(II)NTA-NO and COD utilization. The Fe(II)NTA-NO reduction efficiency reached 87.8 % at a loading rate of 0.24 mmol L(-1) h(-1), while the scrubber efficiency reached more than 75 % with 250 ppm NO. Stover-Kincannon and a Plug-flow kinetic model based on Michaelis-Menten equation were used to describe the UAPBR performance with respect to Fe(II)NTA-NO and COD removal. The Stover-Kincannon model was found capable of describing the Fe(II)NTA-NO reduction (R m = 8.92 mM h(-1) and K NO = 11.46 mM h(-1)) while plug-flow model provided better fit to the COD utilization (U m = 66.62 mg L(-1) h(-1), K COD = 7.28 mg L(-1)). Analyses for pH, Fe(III)NTA, ammonium, nitrite concentration, and FTIR analysis of the medium samples indicated degradation of NTA, which leads to ammonium and nitrite accumulation in the medium, and affect the regeneration process.

  8. Continuous-flow enantioselective α-aminoxylation of aldehydes catalyzed by a polystyrene-immobilized hydroxyproline

    Directory of Open Access Journals (Sweden)

    Xacobe C. Cambeiro

    2011-10-01

    Full Text Available The application of polystyrene-immobilized proline-based catalysts in packed-bed reactors for the continuous-flow, direct, enantioselective α-aminoxylation of aldehydes is described. The system allows the easy preparation of a series of β-aminoxy alcohols (after a reductive workup with excellent optical purity and with an effective catalyst loading of ca. 2.5% (four-fold reduction compared to the batch process working at residence times of ca. 5 min.

  9. Anaerobic transformation of chlorinated hydrocarbons in a packed-bed reactor

    NARCIS (Netherlands)

    Best, Jappe Hinco de

    1999-01-01

    Chlorinated aliphatic hydrocarbons belong to the most frequently found contaminants in soil. Because of their toxicity and persistence, they are a potential threat to human health and the diversity of ecosystems. For the cleanup of soils contaminated with these compounds, biological degradation by

  10. The catalytic oxidation of organic contaminants in a packed bed reactor

    NARCIS (Netherlands)

    van de Beld, L.; Bijl, M.P.G.; Reinders, A.; van der Wert, B.; Westerterp, K.R.

    1994-01-01

    The catalytic oxidation of several hydrocarbons was studied over noble metal and metal oxide catalysts. A fast empirical method was developed to determine the minimum operating temperature required to guarantee complete conversion of the hydrocarbon. The influence of the operating parameters such as

  11. Verification of Heat and Mass Transfer Closures in Industrial Scale Packed Bed Reactor Simulations

    Directory of Open Access Journals (Sweden)

    Arpit Singhal

    2018-03-01

    Full Text Available Particle-resolved direct numerical simulation (PR-DNS is known to provide an accurate detailed insight into the local flow phenomena in static particle arrays. Most PR-DNS studies in literature do not account for reactions taking place inside the porous particles. In this study, PR-DNS is performed for catalytic reactions inside the particles using the multifluid approach where all heat and mass transfer phenomena are directly resolved both inside and outside the particles. These simulation results are then used to verify existing 1D model closures from literature over a number of different reaction parameters including different reaction orders, multiple reactions and reactants, interacting reactions, and reactions involving gas volume generation/consumption inside the particle. Results clearly showed that several modifications to existing 1D model closures are required to reproduce PR-DNS results. The resulting enhanced 1D model was then used to accurately simulate steam methane reforming, which includes all of the aforementioned reaction complexities. The effect of multiple reactants was found to be the most influential in this case.

  12. Biodegradation of synthetic dyes by Irpex lacteus in liquid cultures and in packed-bed reactor

    Czech Academy of Sciences Publication Activity Database

    Novotný, Čeněk; Svobodová, Kateřina; Kasinath, Aparna; Erbanová, Pavla

    2004-01-01

    Roč. 53, - (2004), s. 206 ISSN 0964-8305. [International Biodeterioration & Biodegradation Symposium /12./. Praha, 14.07.2002-18.07.2002] R&D Projects: GA ČR GA526/00/1303 Institutional research plan: CEZ:AV0Z5020903 Keywords : pw ones * mnp Subject RIV: EE - Microbiology, Virology Impact factor: 0.835, year: 2004

  13. Experimental and Numerical Research Activity on a Packed Bed TES System

    Directory of Open Access Journals (Sweden)

    Mario Cascetta

    2016-09-01

    Full Text Available This paper presents the results of experimental and numerical research activities on a packed bed sensible thermal energy storage (TES system. The TES consists of a cylindrical steel tank filled with small alumina beads and crossed by air used as the heat transfer fluid. Experimental tests were carried out while varying some operating parameters such as the mass flow rate, the inlet–outlet temperature thresholds and the aspect ratio (length over diameter. Numerical simulations were carried out using a one-dimensional model, specifically developed in the Matlab-Simulink environment and a 2D axisymmetric model based on the ANSYS-Fluent platform. Both models are based on a two-equation transient approach to calculate fluid and solid phase temperatures. Thermodynamic properties were considered to be temperature-dependent and, in the Computational Fluid Dynamics (CFD model, variable porosity of the bed in the radial direction, thermal losses and the effective conductivity of the alumina beads were also considered. The simulation results of both models were compared to the experimental ones, showing good agreement. The one-dimensional model has the advantage of predicting the axial temperature distribution with a very low computational cost, but it does not allow calculation of the correct energy stored when the temperature distribution is strongly influenced by the wall. To overcome this problem a 2D CFD model was used in this work.

  14. Fluid dynamics of air in a packed bed: velocity profiles and the continuum model assumption

    Directory of Open Access Journals (Sweden)

    NEGRINI A. L.

    1999-01-01

    Full Text Available Air flow through packed beds was analyzed experimentally under conditions ranging from those that reinforce the effect of the wall on the void fraction to those that minimize it. The packing was spherical particles, with a tube-to-particle diameter ratio (D/dp between 3 and 60. Air flow rates were maintained between 1.3 and 4.44 m3/min, and gas velocity was measured with a Pitot tube positioned above the bed exit. Measurements were made at various radial and angular coordinate values, allowing the distribution of air flow across the bed to be described in detail. Comparison of the experimentally observed radial profiles with those derived from published equations revealed that at high D/dp ratios the measured and calculated velocity profiles behaved similarly. At low ratios, oscillations in the velocity profiles agreed with those in the voidage profiles, signifying that treating the porous medium as a continuum medium is questionable in these cases.

  15. Isotope exchange reaction in Li2ZrO3 packed bed

    International Nuclear Information System (INIS)

    Kawamura, Y.; Enoeda, M.; Okuno, K.

    1998-01-01

    To understand the release behavior of bred tritium in a solid breeder blanket, the tritium transfer rate and tritium inventory for various mass transfer processes should be investigated. The contribution of the surface reactions (adsorption, desorption and two kinds of isotope exchange reactions) to the release process cannot be ignored. It is believed that two kinds of isotope exchange reactions (gaseous hydrogen-tritiated water and water vapor-tritiated water) occur on the surface of the solid breeder materials when hydrogen is added to the sweep gas to enhance the tritium release rate. The isotope exchange reaction study in H-D systems was carried out using a Li 2 ZrO 3 packed bed. The exchange reaction between gaseous hydrogen and water was the rate controlling step among the two kinds of exchange reactions. The reaction rate constants were quantified, and experimental equations were proposed. The equilibrium constant of the isotope exchange reaction in the H-D system was obtained from experimental data and was found to be 1.17. (orig.)

  16. Power generation by packed-bed air-cathode microbial fuel cells

    KAUST Repository

    Zhang, Xiaoyuan

    2013-08-01

    Catalysts and catalyst binders are significant portions of the cost of microbial fuel cell (MFC) cathodes. Many materials have been tested as aqueous cathodes, but air-cathodes are needed to avoid energy demands for water aeration. Packed-bed air-cathodes were constructed without expensive binders or diffusion layers using four inexpensive carbon-based materials. Cathodes made from activated carbon produced the largest maximum power density of 676±93mW/m2, followed by semi-coke (376±47mW/m2), graphite (122±14mW/m2) and carbon felt (60±43mW/m2). Increasing the mass of activated carbon and semi-coke from 5 to ≥15g significantly reduced power generation because of a reduction in oxygen transfer due to a thicker water layer in the cathode (~3 or ~6cm). These results indicate that a thin packed layer of activated carbon or semi-coke can be used to make inexpensive air-cathodes for MFCs. © 2013 Elsevier Ltd.

  17. Treatment of amoxicillin by O3/Fenton process in a rotating packed bed.

    Science.gov (United States)

    Li, Mo; Zeng, Zequan; Li, Yingwen; Arowo, Moses; Chen, Jianfeng; Meng, Hong; Shao, Lei

    2015-03-01

    In this study, simulated amoxicillin wastewater was treated by the O3/Fenton process in a rotating packed bed (RPB) and the results were compared with the Fenton process and the O3 followed by Fenton (O3 + Fenton) process. The chemical oxygen demand (COD) removal rate and the ratio of 5-day biological oxygen demand to chemical oxygen demand (BOD5/COD) in the O3/Fenton process were approximately 17% and 26%, respectively, higher than those in the O3 + Fenton process with an initial pH of 3. The COD removal rate of the amoxicillin solution reached maximum at the Fe(II) concentration of 0.6 mM, temperature of 25 °C, rotation speed of 800 rpm and initial pH of 3. The BOD5/COD of the amoxicillin solution increased from 0 to 0.38 after the solution was treated by the O3/Fenton process. Analysis of the intermediates indicated that the pathway of amoxicillin degradation in the O3/Fenton process was similar to that in the O3 + Fenton process. Contrast experiment results showed that amoxicillin degradation was significantly intensified in the RPB. Copyright © 2014 Elsevier Ltd. All rights reserved.

  18. Influence of liquid and gas flow rates on sulfuric acid mist removal from air by packed bed tower

    Directory of Open Access Journals (Sweden)

    Jafari Mohammad Javad

    2012-12-01

    Full Text Available Abstract The possible emission of sulfuric acid mists from a laboratory scale, counter-current packed bed tower operated with a caustic scrubbing solution was studied. Acid mists were applied through a local exhaust hood. The emissions from the packed bed tower were monitored in three different categories of gas flow rate as well as three liquid flow rates, while other influencing parameters were kept almost constant. Air sampling and sulfuric acid measurement were carried out iso-kinetically using USEPA method 8. The acid mists were measured by the barium-thorin titration method. According to the results when the gas flow rate increased from 10 L/s to 30 L/s, the average removal efficiency increased significantly (p 3, respectively. L/G of 2–3 was recommended for designing purposes of a packed tower for sulfuric acid mists and vapors removal from contaminated air stream.

  19. Performance of a new solar air heater with packed-bed latent storage energy for nocturnal use

    International Nuclear Information System (INIS)

    Bouadila, Salwa; Kooli, Sami; Lazaar, Mariem; Skouri, Safa; Farhat, Abdelhamid

    2013-01-01

    Highlights: • A new solar air heater collector using a phase change material. • Experimental study of the new solar air heater collector with latent storage. • Energy and exergy analysis of the solar heater with latent storage collector. • Nocturnal use of solar air heater collector. - Abstract: An experimental study was conducted to evaluate the thermal performance of a new solar air heater collector using a packed bed of spherical capsules with a latent heat storage system. Using both first and second law of thermodynamics, the energetic and exegetic daily efficiencies were calculated in Closed/Opened and Opened cycle mode. The solar energy was stored in the packed bed through the diurnal period and extracted at night. The experimentally obtained results are used to analyze the performance of the system, based on temperature distribution in different localization of the collectors. The daily energy efficiency varied between 32% and 45%. While the daily exergy efficiency varied between 13% and 25%

  20. Submicron and Nanoparticulate Matter Removal by HEPA-Rated Media Filters and Packed Beds of Granular Materials

    Science.gov (United States)

    Perry, J. L.; Agui, J. H.; Vijayakimar, R

    2016-01-01

    Contaminants generated aboard crewed spacecraft by diverse sources consist of both gaseous chemical contaminants and particulate matter. Both HEPA media filters and packed beds of granular material, such as activated carbon, which are both commonly employed for cabin atmosphere purification purposes have efficacy for removing nanoparticulate contaminants from the cabin atmosphere. The phenomena associated with particulate matter removal by HEPA media filters and packed beds of granular material are reviewed relative to their efficacy for removing fine (less than 2.5 micrometers) and ultrafine (less than 0.01 micrometers) sized particulate matter. Considerations are discussed for using these methods in an appropriate configuration to provide the most effective performance for a broad range of particle sizes including nanoparticulates.

  1. The adsorption of copper in a packed-bed of chitosan beads: Modeling, multiple adsorption and regeneration

    OpenAIRE

    Neomagus, Hein W J P; Osifo, Peter O; Everson, Raymond C; Webster, Athena; Gun, Marius A

    2009-01-01

    In this study, exoskeletons of Cape rock lobsters were used as raw material in the preparation of chitin that was successively deacetylated to chitosan flakes. The chitosan flakes were modified into chitosan beads and the beads were cross-linked with glutaraldehyde in order to study copper adsorption and regeneration in a packed-bed column. Five consecutive adsorption and desorption cycles were carried out and a chitosan mass loss of 25% was observed, after the last cycle. Despite the loss of...

  2. Operational parameters and their influence on particle-side mass transfer resistance in a packed bed bioreactor

    OpenAIRE

    Hussain, Amir; Kangwa, Martin; Yumnam, Nivedita; Fernandez-Lahore, Marcelo

    2015-01-01

    The influence of internal mass transfer on productivity as well as the performance of packed bed bioreactor was determined by varying a number of parameters; chitosan coating, flow rate, glucose concentration and particle size. Saccharomyces cerevisiae cells were immobilized in chitosan and non-chitosan coated alginate beads to demonstrate the effect on particle side mass transfer on substrate consumption time, lag phase and ethanol production. The results indicate that chitosan coating, bead...

  3. Experimental research of pressure drop in packed beds of monosized spheres a novel correlation for pressure drop calculation

    Directory of Open Access Journals (Sweden)

    Stamenić Mirjana S.

    2017-01-01

    Full Text Available Flow through packed beds of spheres is a complex phenomenon and it has been extensively studied. Although, there is many different correlations there is still no reliable universal equation for prediction of pressure drop. The paper presents the results of experimental research of pressure drop in packed bed of monosized spheres of three different diameters, 8, 11, and 13 mm set within cylindrical vessel of diameter dk = 74 mm, and two different heights of packed bed, hs = 300 and 400 mm. It has been proposed modification of widely used Ergun’s equation in the form of fp = [150+1.3•(Rep/(1-ε]•(1-ε2/(ε3×Rep and new correlation fp = 1/[(27.4-25700•dh/Rep+0.545+6.85•dh] for pressure drop calculation in simple and convenient form for hand and computer calculations. For total number of 362 experimental runs the correlation ratio of the modified Ergun’s relation was CR = 99.3%, and standard deviation SD = 12.2%, while novel relation has CR = 93.7% and SD = 5.4%. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. 33049

  4. METHOD OF CALCULATION OF THE NON-STATIONARY TEMPERATURE FIELD INSIDE OF THERMAL PACKED BED ENERGY STORAGE

    Directory of Open Access Journals (Sweden)

    Ermuratschii V.V.

    2014-04-01

    Full Text Available e paper presents a method of the approximate calculation of the non-stationary temperature field inside of thermal packed bed energy storages with feasible and latent heat. Applying thermoelectric models and computational methods in electrical engineering, the task of computing non-stationary heat transfer is resolved with respect to third type boundary conditions without applying differential equations of the heat transfer. For sub-volumes of the energy storage the method is executed iteratively in spatiotemporal domain. Single-body heating is modeled for each sub-volume, and modeling conditions are assumed to be identical for remained bod-ies, located in the same sub-volume. For each iteration step the boundary conditions will be represented by re-sults at the previous step. The fulfillment of the first law of thermodynamics for system “energy storage - body” is obtained by the iterative search of the mean temperature of the energy storage. Under variable boundary con-ditions the proposed method maybe applied to calculating temperature field inside of energy storages with packed beds consisted of solid material, liquid and phase-change material. The method may also be employed to compute transient, power and performance characteristics of packed bed energy storages.

  5. Water infiltration and heat transfer in one dimensional unsaturated packed beds; Fuhowa ryushi sonai no ichijigen suibun nagare to dennetsu tokusei

    Energy Technology Data Exchange (ETDEWEB)

    Aoki, K; Akahori, M; Hattori, M [Nagaoka University of Technology, Niigata (Japan); Shiraishi, N [Toshiba Corp., Tokyo (Japan)

    1998-05-25

    Water and heat transport in unsaturated packed beds due to supplying hot water have been investigated experimentally and theoretically. Using various sizes of glass beads, capillary pressure and permeability in packed beds were measured in unsaturated beds. The distributions in water saturation and temperature were predicted for one dimensional packed bed, based on a model assuming local thermal equilibrium among water, gas and particles at any specific space. The predicted temperature distributions were compared with the experimental results obtained using various glass sizes. In layered packed beds, water saturation becomes discontinuous at the interface of two layers because of the difference of the water characteristics between two beds. Water penetrates faster in coarse-over fine-textured profile compared with in fine-over coarse-textured profile. Similarly, the temperature rises faster in former profile under the same supplied heat quantity. 11 refs., 13 figs., 1 tab.

  6. Permeability change with dissolution and precipitation reaction induced by highly alkaline plume in packed bed with amorphous silica particles

    International Nuclear Information System (INIS)

    Komatsu, Kyo; Kadowaki, Junichi; Niibori, Yuichi; Mimura, Hitoshi; Usui, Hideo

    2008-01-01

    A large amount of cement is used to construct of the geological disposal system. Such a material alters the pH of groundwater to highly alkaline region. The highly alkaline plume contains rich Ca ion compared to the surrounding environment, and the Ca ion reacts with soluble silicic acid. Its product would deposit on the surface of flow-paths in the natural barrier and decrease the permeability. In this study, the influence of Ca ions in highly alkaline plume on flow-paths has been examined by using packed bed column. The column was packed with the amorphous silica particles of 75-150 μm in diameter. The Ca(OH) 2 solution (0.78 mM, 2.58 mM, 4.37 mM, and 8.48 mM, pH: 12.2-12.4) was continuously injected into the column at a constant flow rate (5 ml/min, and 2 ml/min), and the change of permeability was monitored. At the same time, the concentrations of [Ca] total and [Si] in the eluted solution were measured by the inductively coupled plasma atomic emission spectrometry (ICP-AES). The Ca(OH) 2 solutions were prepared with CO 2 -free pure water, and filtrated through 0.45 μm filter. The permeability was normalized by the initial permeability value. In the experiment results, the permeability dramatically changed with increasing Ca concentration, because Ca ions and H 4 SiO 4 (due to the dissolution of SiO 2 ) produce C-S-H gel between the packed particles in the column. The SEM images and XRD analyses showed that the surface of SiO 2 particles was covered with the C-S-H gel precipitation. On the other hand, when the Ca concentration was relatively low, the permeability did not show remarkable change. For the cross section of SiO 2 particles, EPMA analysis suggested the consumption of Ca in the inner pore of the SiO 2 particles. However, the time-change in the concentrations of Si and Ca was not always simple. Such time-change strongly depended not only on pH or Ca concentration, but also on the flow rates. This suggested that mass transport controls the chemical

  7. Gas flow calculation with a turbulence model in a packed bed; Ranryu model wo mochiita juten sonai no gas nagare no keisan

    Energy Technology Data Exchange (ETDEWEB)

    Takeda, K [Kawasaki Steel Corp., Tokyo (Japan); Lockwood, F

    1996-06-01

    For the rationalization of blast furnace operation, the gas flow in a packed bed is calculated using a turbulence model. For accurately determining the mixing of gasses, dispersion of particulates in a turbulence, turbulence diffusion, response rate, etc., in a packed bed, turbulence characteristics need be elucidated. For the calculation of combustion behavior of powdered coal blown into the blast furnace tuyere, in particular, the evaluation of gas turbulence behavior in the blow pipe and packed bed is indispensable. The dissipation rate of {kappa} has been defined from the mixing length Lm with the hydraulic diameter of the packed bed as its function and the turbulence energy ({kappa}), and now a {kappa}-Lm model is proposed, capable of evaluating the turbulence behavior in the packed bed. The parameters in the model may be determined using the actually measured values about diffusion behavior. The diffusion behavior of a tracer blown into the packed bed is simulated, and then agreement is found between the calculated values and measured values. Oxygen distribution under simplified raceway conditions is calculated. Once in the raceway, the radial concentration gradient of oxygen is much gentler suddenly, indicating the excellent mixture characteristics of the packed layer. 21 refs., 9 figs.

  8. Mechanical and Structural Behavior of Granular Material Packed Beds for Space Life Support System Applications

    Science.gov (United States)

    Malla, Ramesh B.; Anandakumar, Ganesh

    2005-01-01

    Long-term human mission to space, such as living in International Space Station (ISS), Lunar, and Martian bases, and travel to Mars, must m ake use of Advanced Life Support Systems (ALSS) to generate and recycle critical life supporting elements like oxygen and water. Oxygen Gen eration Assembly (OGA) and Water Processor Assembly (WPA), critical c omponents of ALSS, make use of series of granular material packed beds for generation and recycling of oxygen and water. Several granular m aterials can be used for generation, recycling, processing and recovery of oxygen and water. For example, they may include soft bed media, e.g. ion exchange resins for oxygen generation assembly and hard bed media such as, activated alumina, magchem (Magnesium oxide) and activa ted carbon to remove organic species like ethanol, methanol, and urea from wastewater in Water recovery/processing assembly. These beds are generally packed using a plate-spring mechanism to provide sufficien t compaction to the bed media throughout the course of operation. This paper presents results from an experimental study of a full-scale, 3 8.1 cm (15 inches) long and 3.7 cm (1.44 inches) diameter. activated alumina bed enclosed in a cylinder determining its force-displacement behavior, friction mobilizing force, and axial normal stress distribu tion under various axially applied loads and at different levels of packing. It is observed that force-displacement behavior is non-linear for low compaction level and becomes linear with increase in compaction of the bed media. Axial normal stress distribution along the length of the bed media decreased non-linearly with increase in depth from the loading end of the granular media. This paper also presents experimental results on the amount of particulates generated corresponding to various compaction levels. Particulates generated from each of the tests were measured using standard US sieves. It was found that the p articulates and the overall displacement of

  9. EXPERIMENTAL STUDY ON HEAT TRANSFER COEFFICIENT AND FRICTION FACTOR OF Al2O3 NANOFLUID IN A PACKED BED COLUMN

    Directory of Open Access Journals (Sweden)

    G. Srinivasa Rao

    2011-12-01

    Full Text Available The forced convection heat transfer coefficient and friction factor are determined for the flow of water and nanofluid in a vertical packed bed column. The analysis is undertaken in the laminar and transition Reynolds number range. The column is filled with spherical glass beads as the bed material. The heat transfer coefficients with Al2O3 nanofluid increased by 12% to 15% with the increase of volume concentration from 0.02% to 0.5% compared with water. The experimental values of axial temperature are in good agreement with the NTU-ε method proposed by Schumann’s model.

  10. Perchlorate remediation using packed-bed bioreactors and electricity generation in microbial fuel cells (MFCs)

    Science.gov (United States)

    Min, Booki

    Two pilot-scale fixed bed bioreactors were operated in continuous mode in order to treat groundwater contaminated by perchlorate. The bioreactors were constructed and operated side-by-side at the Texas Street Well Facility in Redlands, California. Each reactor was packed with either sand or plastic media. A perchlorate-reducing bacterium, Dechlorosoma sp. KJ, was used to inoculate the bioreactors. Perchlorate was successfully removed down to a non-detectable level (microbial fuel cells (MFCs), which were run either in batch or continuous mode. In batch experiments, both a pure culture (Geobactor metallireducens) and a mixed culture (wastewater inoculum) were used as the biocatalyst, and acetate was added as substrate in the anode chamber of the MFC. Power output in a membrane MFC with either inoculum was essentially the same, with 40 +/- 1 mW/m2 for G. metallireducens and 38 +/- 1 mW/m2 for mixed culture. A different type of the MFC containing a salt bridge instead of a membrane system was examined to generate power using the same substrate and pure culture as used in the membrane MFC. Power output in the salt bridge MFC was 2.2 mW/m 2. It was found that the lower power output was directly attributed to the higher internal resistance of the salt bridge system (19920 +/- 50 O) in comparison with that of the membrane system (1286 +/- 1 O). Continuous electricity generation was examined in a flat plate microbial fuel cell (FPMFC) using domestic wastewater and specific organic substrates. The FPMFC, containing a combined electrode/proton exchange membrane (PEM), was initially acclimated for one month to domestic wastewater, and then was operated as a plug flow reactor system. Power density using domestic wastewater as a substrate was 72 +/- 1 mW/m2 at a liquid flow rate of 0.39 mL/min (1.1 hr hydraulic retention time, HRT), and COD removal was 42%. At a longer HRT of 4.0 hr, the COD removal increased to 79%, and power density was 43 mW/m2. Several organic compounds

  11. Continuous surveillance of reactor coolant circuit integrity

    International Nuclear Information System (INIS)

    1986-01-01

    Continuous surveillance is important to assuring the integrity of a reactor coolant circuit. It can give pre-warning of structural degradation and indicate where off-line inspection should be focussed. These proceedings describe the state of development of several techniques which may be used. These involve measuring structural vibration, core neutron noise, acoustic emission from cracks, coolant leakage, or operating parameters such as coolant temperature and pressure. Twenty three papers have been abstracted and indexed separately for inclusion in the data base

  12. Lead Biosorption by Self-Immobilized Rhizopus nigricans Pellets in a Laboratory Scale Packed Bed Column: Mathematical Model and Experiment

    Directory of Open Access Journals (Sweden)

    Adela Kogej

    2010-01-01

    Full Text Available The biosorption of lead ions from aqueous solution on a self-immobilized Rhizopus nigricans biomass has been studied. Experiments were performed in a laboratory scale packed bed column at different liquid flow rates and biosorbent bed heights. Recorded experimental breakthrough curves were compared to those predicted by a mathematical model, which was developed to simulate a packed bed biosorption process by a soft, self-immobilized fungal biosorbent. In the range of examined experimental conditions, the biomass characteristics such as pellet porosity and biosorption capacity substantially affected the predicted response curve. General correlations for the estimation of the intra-pellet effective diffusivity, the external mass transfer coefficient, as well as axial dispersion were successfully applied in this biological system with specific mechanical properties. Under the experimental conditions, mass transfer is controlled by the external film resistance, while the intra-pellet mass transfer resistance, as well as the effect of axial dispersion, can be neglected. A new parameter α, the fraction of active biomass, with an average value of α=0.7, was introduced to take into account the specific biomass characteristics, and consequently the observed non-ideal liquid flow through the bed of fungal pellets.

  13. Modelling and Simulation of Packed Bed Catalytic Converter for Oxidation of Soot in Diesel Powered Vehicles Flue Gas

    Directory of Open Access Journals (Sweden)

    Mohammad Nasikin

    2010-10-01

    Full Text Available Diesel vehicle is used in Indonesia in very big number. This vehicle exhausts pollutants especially diesel soot that can be reduces by using a catalytic converter to convert the soot to CO2. To obtain the optimal dimension of catalytic converter it is needed a model that can represent the profile of soot weight, temperature and pressure along the catalytic converter. In this study, a model is developed for packed bed catalytic converter in an adiabatic condition based on a kinetic study that has been  reported previously. Calculation of developed equations in this model uses Polymath 5.X solver with Range Kutta Method. The simulation result shows that temperature profile along catalytic converter increases with the decrease of soot weight,  while pressure profile decreases. The increase of soot weight in entering gas increases the needed converter length. On the other hand, the increase of catalyst diameter does not affect to soot weight along converter and temperature profile, but results a less pressure drop. For 2.500 c diesel engine, packed bed catalytic converter with ellipse's cross sectional of 14,5X7,5 cm diagonal and 0,8 cm catalyst particle diameter, needs 4,1 cm length.

  14. Continuously renewed wall for a thermonuclear reactor

    International Nuclear Information System (INIS)

    Livshits, A.I.; Pustovojt, YU.M.; Samartsev, A.A.; Gosudarstvennyj Komitet po Ispol'zovaniyu Atomnoj Ehnergii SSSR, Moscow. Inst. Atomnoj Ehnergii)

    1982-01-01

    The possibility of creating a continuously renewed first wall of a thermonuclear reactor is experimentally investigated. The following variants of the wall are considered: the wall is double, its part turned to plasma is made of comparatively thin material. The external part separated from it by a small gap appears to be protected from interaction with plasma and performs structural functions. The gap contains the mixture of light helium and hydrogen and carbon-containing gas. The light gas transfers heat from internal part of the wall to the external part. Carbon-containing gas provides continuous renewal of carbon coating of the operating surface. The experiment is performed with palladium membrane 20 μm thick. Carbon is introduced into the membrane by benzol pyrolysis on one of the surfaces at the membrane temperature of 900 K. Carbon removal from the operating side of the wall due to its spraying by fast particles is modelled by chemical itching with oxygen given to the operating membrane wall. Observation of the carbon release on the operating surface is performed mass-spectrometrically according to the observation over O 2 transformation into CO and CO 2 . It is shown that in cases of benzol pressure of 5x10 -7 torr, carbon current on the opposite surface is not less than 3x10 12 atoms/sm 2 s and corresponds to the expected wall spraying rate in CF thermonuclear reactors. It is also shown that under definite conditions the formation and maintaining of a through protective carbon coating in the form of a monolayer or volumetric phase is possible

  15. Efflux Performance of Submicron Particles in Packed Bed under Periodic Pressure Conditions; Shuki atsuho ni yoru juten sonai sabumikuron biryushi no ryushutsu tokusei

    Energy Technology Data Exchange (ETDEWEB)

    Ping, Z; Iritani, E; Murase, T [Nagaya Univ. Nagoya (Japan). Department of Chemical Engineering

    1997-09-01

    Permeation experiments of ultrapure water were conducted under periodic pressure conditions using a packed bed obtained by dispersing submicron particles of polymethyl methacrylate (PMMA) uniformly into a packed bed of particles of White Alundum. It is clearly demonstrated that washing performance under periodic pressure conditions where the permeation pressure is applied periodically is improved dramatically, compared with that under constant pressure conditions. It is also shown that the effect of periodic pressure operation is especially noticeable in the initial stage of the pressurizing period, and that a pressurizing time smaller than 2 min is very effective under conditions examined in this study. 4 figs.

  16. Evaluation of NaX and NaY packed beds for chromium uptake from multicomponent solution

    Directory of Open Access Journals (Sweden)

    Maria Angélica Simões Dornellas de Barros

    2014-04-01

    Full Text Available In this paper the removal of chromium from Cr/Ca/Mg/K and Cr/Ca/Mg/K/Na solutions was investigated in NaX and NaY packed beds. The breakthrough curves presented some overshooting phenomena where chromium ions displaced the previous exchanged cations. Length of unused bed, overall mass transfer coefficient, operational ratio and dimensionless variance were obtained. According to such mass transfer parameters it was concluded that the chromium uptake is influenced by the competition and interaction of the entering ions. Such influences were verified through some differences in the dynamic selectivity obtained for each system. NaY seemed to have a higher affinity towards Cr3+ and its sites were more efficiently used in the ion exchange process.

  17. Mathematical modeling of Kluyveromyces marxianus growth in solid-state fermentation using a packed-bed bioreactor.

    Science.gov (United States)

    Mazutti, Marcio A; Zabot, Giovani; Boni, Gabriela; Skovronski, Aline; de Oliveira, Débora; Di Luccio, Marco; Rodrigues, Maria Isabel; Maugeri, Francisco; Treichel, Helen

    2010-04-01

    This work investigated the growth of Kluyveromyces marxianus NRRL Y-7571 in solid-state fermentation in a medium composed of sugarcane bagasse, molasses, corn steep liquor and soybean meal within a packed-bed bioreactor. Seven experimental runs were carried out to evaluate the effects of flow rate and inlet air temperature on the following microbial rates: cell mass production, total reducing sugar and oxygen consumption, carbon dioxide and ethanol production, metabolic heat and water generation. A mathematical model based on an artificial neural network was developed to predict the above-mentioned microbial rates as a function of the fermentation time, initial total reducing sugar concentration, inlet and outlet air temperatures. The results showed that the microbial rates were temperature dependent for the range 27-50 degrees C. The proposed model efficiently predicted the microbial rates, indicating that the neural network approach could be used to simulate the microbial growth in SSF.

  18. Study on heat and mass transfer between a greenhouse considered as a solar air heater and a rock packed bed as ambient control system

    International Nuclear Information System (INIS)

    Ajona Maeztu, J.I.

    1990-01-01

    A general study on heat transfer in dry packed beds is made, with special emphasis in comparing different transient models and in identifying the required conditions by which the attained results are equivalent. The differences in thermal behaviour on packed beds, when simultaneous heat mass transfer occurs as wet air is used as heat transfer fluid and exchanges heat and water with the solid in the bed, is analyzed. We modelize wet packed beds considering them as one dimension adsorbents beds, with dispersive and non-dispersive models, where adsorption, condensation-evaporation and liquid water downward flow from condensate phenomena are present. Models were solved numerically and experiments with a rock bed with dry and wet air through it, were made to test assumptions and to further understand the behavior of the system, obtaining a pretty good agreement between expected and measured profiles of the temperature evolution within the packed bed. As a possible application of the wet rock bed for storage purposes, a forced ventilation greenhouse was characterized as a wet air solar heater and analyzed the energetic potential of storing the heat that has to be rejected during daytime to control the crop ambient conditions, in a rock bed for later use at night for heating. (author)

  19. Mean ascending velocity of powder entrained by gas in a packed bed; Juten sonai ni okeru kiryu ni dohansareru funtai no heikin josho sokudo

    Energy Technology Data Exchange (ETDEWEB)

    Ariyama, T; Sato, M; Asakawa, Y [NKK Corp., Tokyo (Japan)

    1996-01-20

    For the purpose of clarifying the behavior of fine particles entrained by upward gas in the packed bed like in a blast furnace, the mean ascending velocity of powder in the packed bed was measured by the residence time distribution of the tracer powder. According the results, it was found that the measured velocity was lower than the values predicted by the successive collision model of fine particles. The difference is considered to be caused by the stagnant zone of fine particles on the packed materials, and this behavior was confirmed by the observation in the two dimensional experimental apparatus. Namely, the dynamic hold-up of powder in the packed bed was composed of the particles entrained by the upward gas and the stagnant particles on the packed material, and the latter part was successively renewed by the powder carried by gas. Then, on the basis of the above results, the relation between stagnant time and local ascending velocity were experimentally correlated with solid-gas loading ratio, and it was found that there exists a certain relation among them. The model proposed by these experiments enabled to calculate the mean ascending velocity of powder in the packed bed. 6 refs., 11 figs., 1 tab.

  20. The Phase Behavior Effect on the Reaction Engineering of Transesterification Reactions and Reactor Design for Continuous Biodiesel Production

    Science.gov (United States)

    Csernica, Stephen N.

    plug flow reactors (PFR). Despite this fact, the use of CSTRs is more common than the use of PFRs. This is mostly due to the fact that the two initial reactant phases are relatively immiscible and significant agitation is generally supplied to initiate the reaction. Based on the theoretical results, however, the use of a packed-bed tubular flow reactor was investigated experimentally. A series of two tubular flow reactors was built in the laboratory. The first reactor was of the shell and tube variety and also functioned as a preheater. The second reactor was larger and contained a packed-bed. Two different flow configurations were invested, upflow-upflow and downflow-downflow. It was determined that the downflow-downflow configuration provided significantly better triglyceride conversions that the upflow-upflow configuration.

  1. Stochastic model of flow and dispersion of fine particles in a packed bed; Kakuritsu katei wo mochiita juten sonai deno funtai no ryudo to bunsan model

    Energy Technology Data Exchange (ETDEWEB)

    Takeda, K [Kawasaki Steel Corp., Tokyo (Japan); Lockwood, F

    1996-06-01

    For the calculation of pulverized coal combustion in a blast furnace blow pipe and tuyere, a model was built for the evaluation of the movement and dispersion of particles in a packed bed by use of a stochastic approach. In the stochastic particle trajectory calculation taking into consideration the impact of fluctuations in gas turbulence, interaction distance between particles and eddies and interaction time have to be determined, in addition to fluctuations in gas flow velocity (to be determined by measuring the instantaneous flow velocity in a normal distribution generated according to random numbers). The eddy life was determined using Shuen`s formula on the premise that the particle-eddy interaction occurs within the calculated life or the transit time, whichever is shorter. As for the turbulence energy {kappa}, it was determined by the {kappa}-{epsilon} model for the free space and by the {kappa}-Lm(mixing length) model for the packed bed. From the average of a multiplicity of particles in the experiment, such time average specific values as the average density and flow velocity vectors of particles in the space, and particle trajectories, were calculated, which proved to agree with values from experiments. Once in the packed bed, the pulverized coal underwent a sudden deceleration due to its interaction with particles in the packed bed, and the pulverized coal flow near the central axis was rapidly diffused in the packed bed. This model is expected to find its use in the study of pulverized coal combustion in the blast furnace. 18 refs., 12 figs., 2 tabs.

  2. Investigations on a new internally-heated tubular packed-bed methanol–steam reformer

    KAUST Repository

    Nehe, Prashant; Vanteru, Mahendra Reddy; Kumar, Sudarshan

    2015-01-01

    Small-scale reformers for hydrogen production through steam reforming of methanol can provide an alternative solution to the demand of continuous supply of hydrogen gas for the operation of Proton Exchange Membrane Fuel Cells (PEMFCs). A packed

  3. Analysis of an integrated packed bed thermal energy storage system for heat recovery in compressed air energy storage technology

    International Nuclear Information System (INIS)

    Ortega-Fernández, Iñigo; Zavattoni, Simone A.; Rodríguez-Aseguinolaza, Javier; D'Aguanno, Bruno; Barbato, Maurizio C.

    2017-01-01

    Highlights: •A packed bed TES system is proposed for heat recovery in CAES technology. •A CFD-based approach has been developed to evaluate the behaviour of the TES unit. •TES system enhancement and improvement alternatives are also demonstrated. •TES performance evaluated according to the first and second law of thermodynamics. -- Abstract: Compressed air energy storage (CAES) represents a very attracting option to grid electric energy storage. Although this technology is mature and well established, its overall electricity-to-electricity cycle efficiency is lower with respect to other alternatives such as pumped hydroelectric energy storage. A meager heat management strategy in the CAES technology is among the main reasons of this gap of efficiency. In current CAES plants, during the compression stage, a large amount of thermal energy is produced and wasted. On the other hand, during the electricity generation stage, an extensive heat supply is required, currently provided by burning natural gas. In this work, the coupling of both CAES stages through a thermal energy storage (TES) unit is introduced as an effective solution to achieve a noticeable increase of the overall CAES cycle efficiency. In this frame, the thermal energy produced in the compression stage is stored in a TES unit for its subsequent deployment during the expansion stage, realizing an Adiabatic-CAES plant. The present study addresses the conceptual design of a TES system based on a packed bed of gravel to be integrated in an Adiabatic-CAES plant. With this objective, a complete thermo-fluid dynamics model has been developed, including the implications derived from the TES operating under variable-pressure conditions. The formulation and treatment of the high pressure conditions were found being particularly relevant issues. Finally, the model provided a detailed performance and efficiency analysis of the TES system under charge/discharge cyclic conditions including a realistic operative

  4. Magnetic resonance velocity imaging of liquid and gas two-phase flow in packed beds.

    Science.gov (United States)

    Sankey, M H; Holland, D J; Sederman, A J; Gladden, L F

    2009-02-01

    Single-phase liquid flow in porous media such as bead packs and model fixed bed reactors has been well studied by MRI. To some extent this early work represents the necessary preliminary research to address the more challenging problem of two-phase flow of gas and liquid within these systems. In this paper, we present images of both the gas and liquid velocities during stable liquid-gas flow of water and SF(6) within a packing of 5mm spheres contained within columns of diameter 40 and 27 mm; images being acquired using (1)H and (19)F observation for the water and SF(6), respectively. Liquid and gas flow rates calculated from the velocity images are in agreement with macroscopic flow rate measurements to within 7% and 5%, respectively. In addition to the information obtained directly from these images, the ability to measure liquid and gas flow fields within the same sample environment will enable us to explore the validity of assumptions used in numerical modelling of two-phase flows.

  5. The adsorption of copper in a packed-bed of chitosan beads: modeling, multiple adsorption and regeneration.

    Science.gov (United States)

    Osifo, Peter O; Neomagus, Hein W J P; Everson, Raymond C; Webster, Athena; vd Gun, Marius A

    2009-08-15

    In this study, exoskeletons of Cape rock lobsters were used as raw material in the preparation of chitin that was successively deacetylated to chitosan flakes. The chitosan flakes were modified into chitosan beads and the beads were cross-linked with glutaraldehyde in order to study copper adsorption and regeneration in a packed-bed column. Five consecutive adsorption and desorption cycles were carried out and a chitosan mass loss of 25% was observed, after the last cycle. Despite the loss of chitosan material, an improved efficiency in the second and third cycles was observed with the adsorbent utilizing 97 and 74% of its adsorbent capacity in the second and third cycles, respectively. The fourth and fifth cycles, however, showed a decreased efficiency, and breakage of the beads was observed after the fifth cycle. In the desorption experiments, 91-99% of the adsorbed copper was regenerated in the first three cycles. It was also observed that the copper can be regenerated at a concentration of about a thousand fold the initial concentration. The first cycle of adsorption could be accurately described with a shrinking core particle model combined with a plug flow column model. The input parameters for this model were determined by batch characterization methods, with as only fitting parameter, the effective diffusion coefficient of copper in the bead.

  6. The adsorption of copper in a packed-bed of chitosan beads: Modeling, multiple adsorption and regeneration

    Energy Technology Data Exchange (ETDEWEB)

    Osifo, Peter O., E-mail: petero@vut.ac.za [Department of Chemical Engineering, Vaal University of Technology, P/Bag X021, Vanderbijlpark 1900 (South Africa); Neomagus, Hein W.J.P.; Everson, Raymond C. [School of Chemical and Minerals Engineering, North-West University, P/Bag X6001, Potchefstroom 2520 (South Africa); Webster, Athena [University of Utah, Chemistry Department, Salt Lake City, UT 84112 (United States); Gun, Marius A. vd [Sulzer Elbar B.V., Spikweien 36, NL-5943 AD Lomm (Netherlands)

    2009-08-15

    In this study, exoskeletons of Cape rock lobsters were used as raw material in the preparation of chitin that was successively deacetylated to chitosan flakes. The chitosan flakes were modified into chitosan beads and the beads were cross-linked with glutaraldehyde in order to study copper adsorption and regeneration in a packed-bed column. Five consecutive adsorption and desorption cycles were carried out and a chitosan mass loss of 25% was observed, after the last cycle. Despite the loss of chitosan material, an improved efficiency in the second and third cycles was observed with the adsorbent utilizing 97 and 74% of its adsorbent capacity in the second and third cycles, respectively. The fourth and fifth cycles, however, showed a decreased efficiency, and breakage of the beads was observed after the fifth cycle. In the desorption experiments, 91-99% of the adsorbed copper was regenerated in the first three cycles. It was also observed that the copper can be regenerated at a concentration of about a thousand fold the initial concentration. The first cycle of adsorption could be accurately described with a shrinking core particle model combined with a plug flow column model. The input parameters for this model were determined by batch characterization methods, with as only fitting parameter, the effective diffusion coefficient of copper in the bead.

  7. The adsorption of copper in a packed-bed of chitosan beads: Modeling, multiple adsorption and regeneration

    International Nuclear Information System (INIS)

    Osifo, Peter O.; Neomagus, Hein W.J.P.; Everson, Raymond C.; Webster, Athena; Gun, Marius A. vd

    2009-01-01

    In this study, exoskeletons of Cape rock lobsters were used as raw material in the preparation of chitin that was successively deacetylated to chitosan flakes. The chitosan flakes were modified into chitosan beads and the beads were cross-linked with glutaraldehyde in order to study copper adsorption and regeneration in a packed-bed column. Five consecutive adsorption and desorption cycles were carried out and a chitosan mass loss of 25% was observed, after the last cycle. Despite the loss of chitosan material, an improved efficiency in the second and third cycles was observed with the adsorbent utilizing 97 and 74% of its adsorbent capacity in the second and third cycles, respectively. The fourth and fifth cycles, however, showed a decreased efficiency, and breakage of the beads was observed after the fifth cycle. In the desorption experiments, 91-99% of the adsorbed copper was regenerated in the first three cycles. It was also observed that the copper can be regenerated at a concentration of about a thousand fold the initial concentration. The first cycle of adsorption could be accurately described with a shrinking core particle model combined with a plug flow column model. The input parameters for this model were determined by batch characterization methods, with as only fitting parameter, the effective diffusion coefficient of copper in the bead.

  8. Mathematical Modeling of the Sugar Cane Bagasse'Sprotein Enrichment Processes, in a Packed-Bed Bioreactor

    International Nuclear Information System (INIS)

    Julián-Ricardo, María Caridad; Ramos-Sánchez, Luís Beltrán; Gómez-Atanay, Angel Osvaldo

    2014-01-01

    The residues of the sugar industry have been used usually, natural or processed in the animal alimentation and have been developed a lot of investigations that are allowed obtain protein enrichment products by solid state fermentation (SSF). However, the technologies employed in the production have limitations that are restraining their commercialization. This investigation was directed to find solutions to the problems that are presented and was planted like objective: to obtain a mathematical model for the scale-up of the sugar cane bagasse´s protein enrichment process, using the Candida utilis yeast, in a packed-bed bioreactor. The experimental work was realized in a pilot plant that have an installation for the air accommodation that is supply for the bioreactor, with a temperature of 30 ºC and more than 95 % of relative humidity. Was used a mathematical model compose by a pseudohomogenous energy balance and the mass balances for the biomass overgrowth and the substrate consumption. The validation studies, was realized by the temperatures comparisons axially measure in 10 L and 100 L bioreactor and the temperatures calculated by simulation. The statistic treatment demonstrate that doesn´t exist big differences between the middle temperatures, for a confidence level of 95 %. The analysis realized to characterize the obtained product, allowed establish that it is accord to quality specifications of the protein enrichment feed. (author)

  9. Optimization of the operation of packed bed bioreactor to improve the sulfate and metal removal from acid mine drainage.

    Science.gov (United States)

    Dev, Subhabrata; Roy, Shantonu; Bhattacharya, Jayanta

    2017-09-15

    The present study discusses the potentiality of using anaerobic Packed Bed Bioreactor (PBR) for the treatment of acid mine drainage (AMD). The multiple process parameters such as pH, hydraulic retention time (HRT), concentration of marine waste extract (MWE), total organic carbon (TOC) and sulfate were optimized together using Taguchi design. The order of influence of the parameters towards biological sulfate reduction was found to be pH > MWE > sulfate > HRT > TOC. At optimized conditions (pH - 7, 20% (v/v) MWE, 1500 mg/L sulfate, 48 h HRT and 2300 mg/L TOC), 98.3% and 95% sulfate at a rate of 769.7 mg/L/d. and 732.1 mg/L/d. was removed from the AMD collected from coal and metal mine, respectively. Efficiency of metal removal (Fe, Cu, Zn, Mg and Ni) was in the range of 94-98%. The levels of contaminants in the treated effluent were below the minimum permissible limits of industrial discharge as proposed by Bureau of Indian Standards (IS 2490:1981). The present study establishes the optimized conditions for PBR operation to completely remove sulfate and metal removal from AMD at high rate. The study also creates the future scope to develop an efficient treatment process for sulfate and metal-rich mine wastewater in a large scale. Copyright © 2017 Elsevier Ltd. All rights reserved.

  10. PENGARUH POROSITAS PACKING STEEL WOOL TERHADAP PRESSURE DROP DIDALAM PACKED BED COLUMN PADA DISTILASI CAMPURAN ETANOL-AMIL-ALKOHOL-AIR

    Directory of Open Access Journals (Sweden)

    Trisna Kumala Dhaniswara

    2016-08-01

    Full Text Available Inventories of petroleum fuels are increasingly depleted and will someday run out. These shortcomings can be overcome by using alternative fuels, such as ethanol. Based on this, it is necessary to research and development of ethanol as a fuel. One way is with a separation in a packed distillation column. This study aims to assess the mass transfer phenomena that occur in the process of distilling a mixture of ethanol-water-amyl alcohol packed in column. In addition, this study aims to optimize temperature and reflux to obtain the highest levels of ethanol. This research method uses packed bed distillation system with the batch process. Feed used is synthetic ethanol, water, and solvent. Solvent used were amyl alcohol. Doing distillation with heating temperature is maintained. Distillation is done in the packing of stainless steel wool. Research carried out in a batch process with a variable temperature of  79°C; 84°C; 91°C; and porosity packing 20%; 30%; 40%; 50%; 60%; 70%; 80%.

  11. Removal of nitrate, ammonia and phosphate from aqueous solutions in packed bed filter using biochar augmented sand media

    Directory of Open Access Journals (Sweden)

    El Hanandeh Ali

    2017-01-01

    Full Text Available Nutrients from wastewater are a major source of pollution because they can cause significant impact on the ecosystem. Accordingly, it is important that the nutrient concentrations are kept to admissible levels to the receiving environment. Often regulatory limits are set on the maximum allowable concentrations in the effluent. Therefore, wastewater must be treated to meet safe levels of discharge. In this study, laboratory investigation of the efficiency of packed bed filters to remove nitrate, ammonium and phosphate from aqueous solutions were conducted. Sand and sand augmented with hydrochloric acid treated biochar (SBC were used as packing media. Synthetic wastewater solution was prepared with PO43−, NO3−, NH4+ concentrations 20, 10, 50 mg/L, respectively. Each experiment ran for a period of five days; samples from the effluent were collected on alternate days. All experiments were duplicated. Over the experiment period, the average removal efficiency of PO43−, NO3−, NH4+ were 99.2%, 72.9%, 96.7% in the sand packed columns and 99.2%, 82.3%, 97.4% in the SBC packed columns, respectively. Although, the presence of biochar in the packing media had little effect on phosphate and ammonium removal, it significantly improved nitrate removal.

  12. Transient thermal response of a packed bed for energy storage unit utilizing phase change material: experimental and numerical study

    International Nuclear Information System (INIS)

    Bemansour, A.

    2006-01-01

    The present work concerns the numerical and experimental study of the transient response of a packed bed latent heat thermal energy storage system. Experiments were carried out to measures the transient temperature distributions inside a cylindrical bed, which is randomly packed with spheres having uniform sizes and encapsulated the paraffin wax as a phase change material (PCM), with air as a working fluid. A two-dimensional separate phases formulation is used to develop a numerical analysis of the transient response of the bed, considering the influence of both axial and radial thermal dispersion. The fluid energy equation was transformed by finite difference approximation and solved by alternating direction implicit scheme, while the PCM energy equation was solved using fully explicit scheme. This analysis can be applied for both charging and recovery modes and a broad range of Reynolds numbers. Measurements of both fluid and PCM temperature were conducted at different axial and radial positions and at different operating parameters. Experimental measurements of temperature distribution compare favorably with the numerical results over a broad range of Reynolds numbers.(Author)

  13. Modeling arsenite oxidation by chemoautotrophic Thiomonas arsenivorans strain b6 in a packed-bed bioreactor

    Energy Technology Data Exchange (ETDEWEB)

    Dastidar, Aniruddha, E-mail: andy.dastidar@ky.gov [USEPA Research Participant, Division of Water, Frankfort, KY 40601 (United States); Wang, Yi-Tin, E-mail: ywang@engr.uky.edu [Department of Civil Engineering, University of Kentucky, Lexington (United States)

    2012-08-15

    Arsenic is a major toxic pollutant of concern for the human health. Biological treatment of arsenic contaminated water is an alternative strategy to the prevalent conventional treatments. The biological treatment involves a pre-oxidation step transforming the most toxic form of arsenic, As (III), to the least toxic form, As (V), respectively. This intermediate process improves the overall efficiency of total arsenic removal from the contaminated water. As (III) oxidation by the chemoautotrophic bacterium Thiomonas arsenivorans strain b6 was investigated in a fixed-film reactor under variable influent As (III) concentrations (500-4000 mg/L) and hydraulic residence times (HRTs) (0.2-1 day) for a duration of 137 days. During the entire operation, seven steady-state conditions were obtained with As (III) oxidation efficiency ranging from 48.2% to 99.3%. The strong resilience of the culture was exhibited by the recovery of the bioreactor from an As (III) overloading of 5300 {+-} 400 mg As (III)/L day operated at a HRT of 0.2 day. An arsenic mass balance revealed that As (III) was mainly oxidized to As (V) with unaccounted arsenic ({<=} 4%) well within the analytical error of measurement. A modified Monod flux expression was used to determine the biokinetic parameters by fitting the model against the observed steady-state flux data obtained from operating the bioreactor under a range of HRTs (0.2-1 day) and a constant influent As (III) concentration of 500 mg/L. Model parameters, k = 0.71 {+-} 0.1 mg As (III)/mg cells h, and K{sub s} = 13.2 {+-} 2.8 mg As (III)/L were obtained using a non-linear estimation routine and employing the Marquardt-Levenberg algorithm. Sensitivity analysis revealed k to be more sensitive to model simulations of As (III) oxidation under steady-state conditions than parameter K{sub s}. -- Highlights: Black-Right-Pointing-Pointer As (III) oxidation. Black-Right-Pointing-Pointer Biokinetic parameters. Black-Right-Pointing-Pointer Model validation

  14. Continuous production of pectinase by immobilized yeast cells on spent grains.

    Science.gov (United States)

    Almeida, Catarina; Brányik, Tomás; Moradas-Ferreira, Pedro; Teixeira, José

    2003-01-01

    A yeast strain secreting endopolygalacturonase was used in this work to study the possibility of continuous production of this enzyme. It is a feasible and interesting alternative to fungal batch production essentially due to the specificity of the type of pectinase excreted by Kluyveromyces marxianus CCT 3172, to the lower broth viscosity and to the easier downstream operations. In order to increase the reactors' productivity, a cellulosic carrier obtained from barley spent grains was tested as an immobilization support. Two types of reactors were studied for pectinase production using glucose as a carbon and energy source--a continuous stirred tank reactor (CSTR) and a packed bed reactor (PBR) with recycled flow. The highest value for pectinase volumetric productivity (P(V)=0.98 U ml(-1) h(-1)) was achieved in the PBR for D=0.40 h(-1), a glucose concentration on the inlet of S(in)=20 g l(-1), and a biomass load in the support of X(i)=0.225 g g(-1). The results demonstrate the attractiveness of the packed bed system for pectinase production.

  15. Rapid manganese removal from mine waters using an aerated packed-bed bioreactor.

    Science.gov (United States)

    Johnson, Karen L; Younger, Paul L

    2005-01-01

    In the UK, the Environmental Quality Standard for manganese has recently been lowered to 30 microg/L (annual average), which is less than the UK Drinking Water Inspectorate's Maximum Permitted Concentration Value (50 microg/L). Current passive treatment systems for manganese removal operate as open-air gravel-bed filters, designed to maximize either influent light and/or dissolved oxygen. This requires large areas of land. A novel enhanced bioremediation treatment system for manganese removal has been developed that consists of a passively aerated subsurface gravel bed. The provision of air at depth and the use of catalytic substrates help overcome the slow kinetics usually associated with manganese oxidation. With a residence time of only 8 h and an influent manganese concentration of approximately 20 mg/L, >95% of the manganese was removed. The treatment system also operates successfully at temperatures as low as 4 degrees C and in total darkness. These observations have positive implications for manganese treatment using this technique in both colder climates and where large areas of land are unavailable. Furthermore, as the operation of this passive treatment system continually generates fresh manganese oxyhydroxide, which is a powerful sorbent for most pollutant metals, it potentially has major ancillary benefits as a removal process for other metals, such as zinc.

  16. Evaluation of an activated carbon packed bed for the adsorption of phenols from petroleum refinery wastewater.

    Science.gov (United States)

    El-Naas, Muftah H; Alhaija, Manal A; Al-Zuhair, Sulaiman

    2017-03-01

    The performance of an adsorption column packed with granular activated carbon was evaluated for the removal of phenols from refinery wastewater. The effects of phenol feed concentration (80-182 mg/l), feed flow rate (5-20 ml/min), and activated carbon packing mass (5-15 g) on the breakthrough characteristics of the adsorption system were determined. The continuous adsorption process was simulated using batch data and the parameters for a new empirical model were determined. Different dynamic models such as Adams-Bohart, Wolborsko, Thomas, and Yoon-Nelson models were also fitted to the experimental data for the sake of comparison. The empirical, Yoon-Nelson and Thomas models showed a high degree of fitting at different operation conditions, with the empirical model giving the best fit based on the Akaike information criterion (AIC). At an initial phenol concentration of 175 mg/l, packing mass of 10 g, a flow rate of 10 ml/min and a temperature of 25 °C, the SSE of the new empirical and Thomas models were identical (248.35) and very close to that of the Yoon-Nelson model (259.49). The values were significantly lower than that of the Adams-Bohart model, which was determined to be 19,358.48. The superiority of the new empirical model and the Thomas model was also confirmed from the values of the R 2 and AIC, which were 0.99 and 38.3, respectively, compared to 0.92 and 86.2 for Adams-Bohart model.

  17. Comparative discussion of the activated sludge and packed bed techniques in biological sewage water cleaning; Vergleichende Betrachtung von Belebungs- und Festbettverfahren fuer die biologische Abwasserreinigung

    Energy Technology Data Exchange (ETDEWEB)

    Kroiss, H [Technische Univ., Vienna (Germany). Inst. fuer Wasserguete und Abfallwirtschaft

    1994-12-31

    It is reasonable to state that, given proper planning, erection and careful operation, both activated sludge plants and packed bed reactors with a biofilm are capable of meeting extremely high demands on the quality of the effluent. What was to be shown is the fact that operating behaviour and demands on measurement and control techniques differ considerably. Rating depends on different criteria, according to the technique chosen, and also cost calculation is largely determined in each case by special local conditions. All this makes it difficult to compare solutions with one another or to transfer experience gathered in one plant to another application. So the choice of the best possible method in a given case remains an interesting task.- One must try to make as objective a comparison as possible of different solutions according to the relevant criteria, beyond what is quantifiable merely in terms of finance.- Any decision taken on the basis of such a comparison is bound to reflect also the values that the decision-makers hold. But it should always be possible when taking decisions about processes to leave ideology out of consideration. (orig.) [Deutsch] Es kann festgestellt werden, dass sowohl Belebungsanlagen wie auch Biofilmreaktoren bei richtiger Planung, Errichtung und sorgfaeltigem Betrieb in der Lage sind, auch extrem hohe Ansprueche an die Ablaufguete zu erfuellen. Was gezeigt werden sollte, ist der Umstand, dass erhebliche Unterschiede im Betriebsverhalten und in den Anforderungen an die Mess- und Regeltechnik bestehen. Fuer die Bemessung sind je nach Verfahren andere Kriterien massgebend, und auch fuer die Kostenrechnung gilt, dass die speziellen oertlichen Bedingung bei jedem Anwendungsfall von ausschlaggebender Bedeutung sind. Das alles hat zur Folge, dass es sehr schwierig ist, verschiedene Loesungsmoeglichkeiten miteinander zur vergleichen, oder die Erfahrung von einer Anlage auf einen anderen Anwendungsfall zu uebertragen. Die Auswahl des ``besten

  18. BIODEGRADATION OF SUGARCANE VINASSES BY THE WHITE-ROT FUNGI Pleurotus ostreatus IN A PACKED BED REACTOR

    Directory of Open Access Journals (Sweden)

    W.A. Tapie

    2016-08-01

    Full Text Available Sugarcane vinasses are considered a complex effluent because of its organic load, low pH, high temperature, and by the presence of recalcitrant substances such as melanoidins and phenolic compounds. The aim of this work was to evaluate the potential of the fungus Pleurotus ostreatus to carry out the biodegradation of sugarcane vinasses in a fixed-bed bioreactor. The experiments evidence the potential of the fungus Pleurotus ostreatus to carry out the decolorization (83%, the removal of the Chemical Oxygen Demand (COD=87% and the Biochemical Oxygen Demand (BOD5=92%, the reduction of total suspended solids (83% and volatile suspended solids (72% of vinasses. The technical simplicity of the proposed alternative as well as process performance reveals the potential of the fungus Pleurotus ostreatus for the treatment of sugarcane mill effluents.

  19. Thermal and mechanical behaviour of oxygen carrier materials for chemical looping combustion in a packed bed reactor

    NARCIS (Netherlands)

    Jacobs, M.; Van Noyen, J.; Larring, Y.; McCann, M.; Pishahang, M.; Amini, S.; Ortiz, M.; Galluci, F.; Sint-Annaland, M. V.; Tournigant, D.; Louradour, E.; Snijkers, F.

    2015-01-01

    Chemical looping combustion (CLC) is a promising carbon capture technology where cyclic reduction and oxidation of a metallic oxide, which acts as a solid oxygen carrier, takes place. With this system, direct contact between air and fuel can be avoided, and so, a concentrated CO2 stream is generated

  20. Operational parameters and their influence on particle-side mass transfer resistance in a packed bed bioreactor.

    Science.gov (United States)

    Hussain, Amir; Kangwa, Martin; Yumnam, Nivedita; Fernandez-Lahore, Marcelo

    2015-12-01

    The influence of internal mass transfer on productivity as well as the performance of packed bed bioreactor was determined by varying a number of parameters; chitosan coating, flow rate, glucose concentration and particle size. Saccharomyces cerevisiae cells were immobilized in chitosan and non-chitosan coated alginate beads to demonstrate the effect on particle side mass transfer on substrate consumption time, lag phase and ethanol production. The results indicate that chitosan coating, beads size, glucose concentration and flow rate have a significant effect on lag phase duration. The duration of lag phase for different size of beads (0.8, 2 and 4 mm) decreases by increasing flow rate and by decreasing the size of beads. Moreover, longer lag phase were found at higher glucose medium concentration and also with chitosan coated beads. It was observed that by increasing flow rates; lag phase and glucose consumption time decreased. The reason is due to the reduction of external (fluid side) mass transfer as a result of increase in flow rate as glucose is easily transported to the surface of the beads. Varying the size of beads is an additional factor: as it reduces the internal (particle side) mass transfer by reducing the size of beads. The reason behind this is the distance for reactants to reach active site of catalyst (cells) and the thickness of fluid created layer around alginate beads is reduced. The optimum combination of parameters consisting of smaller beads size (0.8 mm), higher flow rate of 90 ml/min and glucose concentration of 10 g/l were found to be the maximum condition for ethanol production.

  1. A comparison between CFD simulation and experimental investigation of a packed-bed thermal energy storage system

    International Nuclear Information System (INIS)

    Cascetta, Mario; Cau, Giorgio; Puddu, Pierpaolo; Serra, Fabio

    2016-01-01

    Highlights: • Thermocline formation inside a sensible type packed bed during a complete cycle. • Thermal properties of both phases must be temperature-dependent in the simulation. • Bed porosity increases from the center to the container wall. • Thermal dispersion and solid conduction must be considered in the model. • The wall influences the radial temperature profile and the amount of energy stored. - Abstract: This work presents the comparison between CFD and experimental results obtained on a sensible thermal energy storage system based on alumina beads freely poured into a carbon steel tank. Experimental investigations of charging and discharging phases were carried out at a constant mass flow rate using air as heat transfer fluid. The experimental set-up was instrumented with several thermocouples to detect axial and radial temperature distribution as well as reservoir wall temperature. The experimental results were compared with those obtained from CFD simulations carried out with the FLUENT software. The computational domain consists of an axisymmetric tank of cylindrical shape filled with a porous bed coupled with the wall. The governing equations are solved for incompressible turbulent flow and fully developed forced convection, based on the two-phase transient model equation (LTNE-local thermal non-equilibrium) to calculate the temperature of fluid and solid phases. The porosity of the bed is considered variable in the radial direction, while the thermodynamic properties of both phases are temperature-dependent. The influence of the thermal dispersion within the porous bed, as well as the effective conductivity between the beads was considered. The heat transfer coefficient was calculated according to correlation for forced convection within porous media. Numerical results show a good agreement with experimental ones if thermal properties are considered temperature-dependent and the experimental temperature profile at the inlet of the bed is

  2. High power density reactors based on direct cooled particle beds

    Science.gov (United States)

    Powell, J. R.; Horn, F. L.

    Reactors based on direct cooled High Temperature Gas Cooled Reactor (HTGR) type particle fuel are described. The small diameter particle fuel is packed between concentric porous cylinders to make annular fuel elements, with the inlet coolant gas flowing inwards. Hot exit gas flows out along the central channel of each element. Because of the very large heat transfer area in the packed beds, power densities in particle bed reactors (PBRs) are extremely high resulting in compact, lightweight systems. Coolant exit temperatures are high, because of the ceramic fuel temperature capabilities, and the reactors can be ramped to full power and temperature very rapidly. PBR systems can generate very high burst power levels using open cycle hydrogen coolant, or high continuous powers using closed cycle helium coolant. PBR technology is described and development requirements assessed.

  3. Advanced Catalysis Technologies: Lanthanum Cerium Manganese Hexaaluminate Combustion Catalysts for Flat Plate Reactor for Compact Steam Reformers

    Science.gov (United States)

    2008-12-01

    packed-bed steam reformer reactor using an open-flame or radiant burner as the heat source, the rate of heat transfer is limited by wall film and bed...resistances. Heat transfer can be effectively improved by replacing the burner /packed-bed system with parallel channels containing metal foam...combustion reactor was tested using the hexaaluminate catalyst in pellets and supported on FeCrAlloy metal foam. Both tests burned propane and JP-8

  4. Computational study of fluid flow and heat transfer in composite packed beds of spheres with low tube to particle diameter ratio

    International Nuclear Information System (INIS)

    Yang, Jian; Wu, Jiangquan; Zhou, Lang; Wang, Qiuwang

    2016-01-01

    Highlights: • Flow and heat transfer in composite packed beds with low d_t/d_p_e are investigated. • The wall effect would be restrained with radially layered composite packing (RLM). • Heat flux and overall heat transfer efficiency can be improved with RLM packing. - Abstract: The effect of the tube wall on the fluid flow and heat transfer would be important in the packed bed with low tube to particle diameter ratio, which may lead to flow and temperature maldistributions inside, and the heat transfer performance may be lowered. In the present paper, the flow and heat transfer performances in both the composite and uniform packed beds of spheres with low tube to particle diameter were numerically investigated, where the composite packing means randomly packing with non-uniform spheres and the uniform packing means randomly packing with uniform spheres, including radially layered composite packing (RLM), axially layered composite packing (ALM), randomly composite packing (RCM) and randomly uniform packing (RPM). Both the composite and uniform packings were generated with discrete element method (DEM), and the influence of the wall effect on the flow and heat transfer in the packed beds were carefully studied and compared with each other. Firstly, it is found that, the wall effect on the velocity and temperature distributions in the randomly packed bed of uniform spheres (RPM) with low tube to particle diameter ratio were obvious. The average velocity of the near-tube-wall region is higher than that of the inner-tube region in the bed. When the tube wall is adiabatic, the average temperature of the near-tube-wall region is lower. With radially layered composite packing method (RLM), smaller pores would be formed close to the tube wall and big flow channels would be formed in the inner-tube region of the bed, which would be benefit to restrain the wall effect and improve heat transfer in the bed with low tube to particle diameter ratio. Furthermore, it is also

  5. Computational study of fluid flow and heat transfer in composite packed beds of spheres with low tube to particle diameter ratio

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Jian, E-mail: yangjian81@mail.xjtu.edu.cn [Key Laboratory of Thermo-Fluid Science and Engineering, Ministry of Education, School of Energy and Power Engineering, Xi’an Jiaotong University, Xi’an, Shaanxi 710049 (China); Wu, Jiangquan [CSR Research of Electrical Technology and Material Engineering, Zhuzhou, Hunan 412001 (China); Zhou, Lang; Wang, Qiuwang [Key Laboratory of Thermo-Fluid Science and Engineering, Ministry of Education, School of Energy and Power Engineering, Xi’an Jiaotong University, Xi’an, Shaanxi 710049 (China)

    2016-04-15

    Highlights: • Flow and heat transfer in composite packed beds with low d{sub t}/d{sub pe} are investigated. • The wall effect would be restrained with radially layered composite packing (RLM). • Heat flux and overall heat transfer efficiency can be improved with RLM packing. - Abstract: The effect of the tube wall on the fluid flow and heat transfer would be important in the packed bed with low tube to particle diameter ratio, which may lead to flow and temperature maldistributions inside, and the heat transfer performance may be lowered. In the present paper, the flow and heat transfer performances in both the composite and uniform packed beds of spheres with low tube to particle diameter were numerically investigated, where the composite packing means randomly packing with non-uniform spheres and the uniform packing means randomly packing with uniform spheres, including radially layered composite packing (RLM), axially layered composite packing (ALM), randomly composite packing (RCM) and randomly uniform packing (RPM). Both the composite and uniform packings were generated with discrete element method (DEM), and the influence of the wall effect on the flow and heat transfer in the packed beds were carefully studied and compared with each other. Firstly, it is found that, the wall effect on the velocity and temperature distributions in the randomly packed bed of uniform spheres (RPM) with low tube to particle diameter ratio were obvious. The average velocity of the near-tube-wall region is higher than that of the inner-tube region in the bed. When the tube wall is adiabatic, the average temperature of the near-tube-wall region is lower. With radially layered composite packing method (RLM), smaller pores would be formed close to the tube wall and big flow channels would be formed in the inner-tube region of the bed, which would be benefit to restrain the wall effect and improve heat transfer in the bed with low tube to particle diameter ratio. Furthermore, it

  6. Kinetics of propionate conversion in anaerobic continuously stirred tank reactors

    DEFF Research Database (Denmark)

    Bangsø Nielsen, Henrik; Mladenovska, Zuzana; Ahring, Birgitte Kiær

    2008-01-01

    The kinetic parameters of anaerobic propionate degradation by biomass from 7 continuously stirred tank reactors differing in temperature, hydraulic retention time and substrate composition were investigated. In substrate-depletion experiments (batch) the maximum propionate degradation rate, A......-m, was estimated. The results demonstrate that the rate of endogenous substrate (propionate) production should be taken into account when estimating kinetic parameters in biomass from manure-based anaerobic reactors....

  7. Continuous Production of Isomalto-oligosaccharides by Thermo-inactivated Cells of Aspergillus niger J2 with Coarse Perlite as an Immobilizing Material.

    Science.gov (United States)

    Huang, Zhihua; Li, Zhihong; Su, Yongjian; Zhu, Yongfeng; Zeng, Wei; Chen, Guiguang; Liang, Zhiqun

    2018-02-13

    The coarse perlite 40-80 mesh was selected as an immobilizing material and put into a packed bed reactor (PBR) to continuously convert maltose to isomalto-oligosaccharides (IMOs). The PBR was prepared by mixing the thermo-inactivated cells (TIC) from Aspergillus niger J2 strain with the coarse perlite, then the mixture was put into an overpressure-resistant column. Compared with diatomite 40-80 mesh and thin perlite 80-120 mesh in PBR, coarse perlite was chosen as the best filtration aid, when the ratio of coarse perlite versus TIC was 1:1. The thermal and pH stability of the free and immobilized TIC and the optimum conditions for the transglycosylation reactions were determined. The results show that approximately 75 and 82% and 87 and 91% of α-glucosidase activity were reserved for free and immobilized TIC at temperatures from 30 to 60 °C and pH from 3.00 to 7.00 for 12 h, respectively. With 30% malt syrup under the conditions of 50 °C and pH 4.00, a mini-scale packed bed reactor (Mi-PBR) and medium-scale packed bed reactor (Me-PBR) could continuously produce IMO over 25 and 34 days with the yield of effective IMO (eIMO) ≥ 35% and total IMO (tIMO) ≥ 50%, respectively. The strategy of mixing the coarse perlite with TIC in PBR is a novel approach to continuously produce IMO and has great application potential in industry.

  8. Continuous fluid bed reactor for fissionable material

    International Nuclear Information System (INIS)

    Ziegler, D.L.

    1975-01-01

    Plutonium (Pu) purification and plutonium hexafluoride (PuF 6 ) formation are achieved on a continuous basis by feeding particulate material into one end of an elongated and horizontally disposed vessel having an upper section with generally converging side walls and a lower section with generally vertical side walls, compartmented throughout its length by transversely disposed baffles, so that particulate material flows through the vessel in vertical generally zigzag fashion, being fluidized by dispersing gas that enters the compartment from a lower narrow compartment and discharges through an upper widened compartment. Vaporous PuF 6 formed from a reaction between the dispersing gas and the particulate material discharges through the upper widened compartment and solid impurities discharge for collection through a port at a far or distal end of the elongated vessel. (U.S.)

  9. Study of Co-Current and Counter-Current Gas-Liquid Two-Phase Flow Through Packed Bed in Microgravity

    Science.gov (United States)

    Revankar, Shripad T.

    2002-11-01

    The main goal of the project is to obtain new experimental data and development of models on the co-current and counter-current gas-liquid two-phase flow through a packed bed in microgravity and characterize the flow regime transition, pressure drop, void and interfacial area distribution, and liquid hold up. Experimental data will be obtained for earth gravity and microgravity conditions. Models will be developed for the prediction of flow regime transition, void fraction distribution and interfacial area concentration, which are key parameters to characterize the packed bed performance. Thus the specific objectives of the proposed research are to: (1) Develop experiments for the study of the gas liquid two-phase flow through the packed bed with three different flow combinations: co-current down flow, co-current upflow and counter current flow. (2) Develop pore scale and bed scale two-phase instrumentation for measurement of flow regime transition, void distribution and gas-liquid interfacial area concentration in the packed bed. (3) Obtain database on flow regime transition, pressure drop, void distribution, interfacial area concentration and liquid hold up as a function of bed characteristics such as bed particle size, porosity, and liquid properties such as viscosity and surface tension. (4) Develop mathematical model for flow regime transition, void fraction distribution and interfacial area concentration for co-current gas-liquid flow through the porous bed in gravity and micro gravity conditions.(4) Develop mathematical model for the flooding phenomena in counter-current gas-liquid flow through the porous bed in gravity and micro gravity conditions. The present proposal addresses the most important topic of HEDS-specific microgravity fluid physics research identified by NASA 's one of the strategic enterprises, OBPR Enterprise. The proposed project is well defined and makes efficient use of the ground-based parabolic flight research aircraft facility. The

  10. High power density reactors based on direct cooled particle beds

    International Nuclear Information System (INIS)

    Powell, J.R.; Horn, F.L.

    1985-01-01

    Reactors based on direct cooled HTGR type particle fuel are described. The small diameter particle fuel is packed between concentric porous cylinders to make annular fuel elements, with the inlet coolant gas flowing inwards. Hot exit gas flows out long the central channel of each element. Because of the very large heat transfer area in the packed beds, power densities in particle bed reactors (PBR's) are extremely high resulting in compact, lightweight systems. Coolant exit temperatures are high, because of the ceramic fuel temperature capabilities, and the reactors can be ramped to full power and temperature very rapidly. PBR systems can generate very high burst power levels using open cycle hydrogen coolant, or high continuous powers using closed cycle helium coolant. PBR technology is described and development requirements assessed. 12 figs

  11. The influence of process parameters in production of lipopeptide iturin A using aerated packed bed bioreactors in solid-state fermentation.

    Science.gov (United States)

    Piedrahíta-Aguirre, C A; Bastos, R G; Carvalho, A L; Monte Alegre, R

    2014-08-01

    The strain Bacillus iso 1 co-produces the lipopeptide iturin A and biopolymer poly-γ-glutamic acid (γ-PGA) in solid-state fermentation of substrate consisting of soybean meal, wheat bran with rice husks as an inert support. The effects of pressure drop, oxygen consumption, medium permeability and temperature profile were studied in an aerated packed bed bioreactor to produce iturin A, diameter of which was 50 mm and bed height 300 mm. The highest concentrations of iturin A and γ-PGA were 5.58 and 3.58 g/kg-dry substrate, respectively, at 0.4 L/min after 96 h of fermentation. The low oxygen uptake rates, being 23.34 and 22.56 mg O2/kg-dry solid substrate for each air flow rate tested generated 5.75 W/kg-dry substrate that increased the fermentation temperature at 3.7 °C. The highest pressure drop was 561 Pa/m at 0.8 L/min in 24 h. This is the highest concentration of iturin A produced to date in an aerated packed bed bioreactor in solid-state fermentation. The results can be useful to design strategies to scale-up process of iturin A in aerated packed bed bioreactors. Low concentration of γ-PGA affected seriously pressure drop, decreasing the viability of the process due to generation of huge pressure gradients with volumetric air flow rates. Also, the low oxygenation favored the iturin A production due to the reduction of free void by γ-PGA production, and finally, the low oxygen consumption generated low metabolic heat. The results show that it must control the pressure gradients to scale-up the process of iturin A production.

  12. The use of silica gel prepared by sol-gel method and polyurethane foam as microbial carriers in the continuous degradation of phenol.

    Science.gov (United States)

    Brányik, T; Kuncová, G; Páca, J

    2000-08-01

    A mixed microbial culture was immobilized by entrapment into silica gel (SG) and entrapment/ adsorption on polyurethane foam (PU) and ceramic foam. The phenol degradation performance of the SG biocatalyst was studied in a packed-bed reactor (PBR), packed-bed reactor with ceramic foam (PBRC) and fluidized-bed reactor (FBR). In continuous experiments the maximum degradation rate of phenol (q(s)max) decreased in the order: PBRC (598 mg l(-1) h(-1)) > PBR (PU, 471 mg l(-1)h(-1)) > PBR(SG, 394 mg l(-1) h(-1)) > FBR (PU, 161 mg l(-1) h(-1)) > FBR (SG, 91 mg l(-1) h(-1)). The long-term use of the SG biocatalyst in continuous phenol degradation resulted in the formation of a 100-200 microm thick layer with a high cell density on the surface of the gel particles. The abrasion of the surface layer in the FBR contributed to the poor degradation performance of this reactor configuration. Coating the ceramic foam with a layer of cells immobilized in colloidal SiO2 enhanced the phenol degradation efficiency during the first 3 days of the PBRC operation, in comparison with untreated ceramic packing.

  13. Effect of hydraulic retention time on continuous biocatalytic calcification reactor

    International Nuclear Information System (INIS)

    Isik, Mustafa; Altas, Levent; Kurmac, Yakup; Ozcan, Samet; Oruc, Ozcan

    2010-01-01

    High calcium concentrations in the wastewaters are problematic, because they lead to clogging of pipelines, boilers and heat exchangers through scaling (as carbonate, sulfate or phosphate precipitates), or malfunctioning of aerobic and anaerobic reactors. As a remedy to this problem, the industry typically uses chemical crystallization reactors which are efficient but often require complex monitoring and control and, as a drawback, can give rise to highly alkaline effluents. Biomineralization are emerging as alternative mechanisms for the removal of calcium from aqueous environments. Biocatalytic calcification reactors (BCR) utilize microbial urea hydrolysis by bacteria for the removal of calcium, as calcite, from industrial wastewater. Hydraulic retention time (HRT) effect on calcium removal was studied with a continuous feed BCR reactor treating a simulated pulp paper wastewater. Study showed that HRT is important parameter and HRT of 5-6 h is optimum for calcium removal from calcium-rich wastewaters.

  14. Use of tower reactors for continuous ethanol production

    Directory of Open Access Journals (Sweden)

    M.C. Viegas

    2002-04-01

    Full Text Available The purpose of this work was to develop a continuous fermentation system operating with a tower reactor using some flocculent yeast strains isolated from an industrial process. The strain was an used in the trial of the proposed system, composed of two serial glass tower reactor. The effects of the following variables were studied on the yield and productivity of the system: total reducing sugar (TRS, concentration in feeding, recycle flow in the second reactor, residence time and diameter/height ratio of the reactors. It was observed that the TRS concentration in feeding and residence time is the variables that interfere most with the productivity of the system. Yield was not affected by any of the variables within the range of values studied. All trials were performed according to a factorial experimental design (making up a total of 19 trials and the results were evaluated by response surface.

  15. Performance and regeneration of a pellet-packed-bed diesel-particulate trap; Ryutai jutenso diesel biryushi trap no seino oyobi saisei

    Energy Technology Data Exchange (ETDEWEB)

    Shioji, M; Nakai, S; Ikegami, M [Kyoto University, Kyoto (Japan); Hori, Y [Yamaha Motor Co. Ltd., Shizuoka (Japan)

    1997-10-01

    This paper demonstrates with the feasibility of a pellet-packed bed for trapping diesel particulates. After making pellets loose from the packed condition, regeneration is established by a circulation of pellets in the trap and collected particulates are efficiently dropped out through the wire mesh on the bottom of the trap. An experimental trap with the pellet-circulation system using a spiral feeder is tested on a single-cylinder test engine to show the trap and regeneration efficiencies. In addition, the condition of pellet circulation is observed using the transparent cylinder, based on which the design of pellet and trap sizes are discussed. 6 refs., 10 figs.

  16. Modeling and Simulation of the Hydrogenation of α-Methylstyrene on Catalytically Active Metal Foams as Tubular Reactor Packing

    Directory of Open Access Journals (Sweden)

    Farzad Lali

    2016-01-01

    Full Text Available This work presents a one-dimensional reactor model for a tubular reactor packed with a catalytically active foam packing with a pore density of 30 PPI in cocurrent upward flow in the example of hydrogenation reaction of α-methylstyrene to cumene. This model includes material, enthalpy, and momentum balances as well as continuity equations. The model was solved within the parameter space applied for experimental studies under assumption of a bubbly flow. The method of orthogonal collocation on finite elements was applied. For isothermal and polytropic processes and steady state conditions, axial profiles for concentration, temperature, fluid velocities, pressure, and liquid holdup were computed and the conversions for various gas and liquid flow rates were validated with experimental results. The obtained results were also compared in terms of space time yield and catalytic activity with experimental results and stirred tank and also with random packed bed reactor. The comparison shows that the application of solid foams as reactor packing is advantageous compared to the monolithic honeycombs and random packed beds.

  17. Optimization of lipase production by solid-state fermentation of olive pomace: from flask to laboratory-scale packed-bed bioreactor.

    Science.gov (United States)

    Oliveira, Felisbela; Salgado, José Manuel; Abrunhosa, Luís; Pérez-Rodríguez, Noelia; Domínguez, José M; Venâncio, Armando; Belo, Isabel

    2017-07-01

    Lipases are versatile catalysts with many applications and can be produced by solid-state fermentation (SSF) using agro-industrial wastes. The aim of this work was to maximize the production of Aspergillus ibericus lipase under SSF of olive pomace (OP) and wheat bran (WB), evaluating the effect on lipase production of C/N ratio, lipids, phenols, content of sugars of substrates and nitrogen source addition. Moreover, the implementation of the SSF process in a packed-bed bioreactor and the improvement of lipase extraction conditions were assessed. Low C/N ratios and high content of lipids led to maximum lipase production. Optimum SSF conditions were achieved with a C/N mass ratio of 25.2 and 10.2% (w/w) lipids in substrate, by the mixture of OP:WB (1:1) and supplemented with 1.33% (w/w) (NH 4 ) 2 SO 4 . Studies in a packed-bed bioreactor showed that the lower aeration rates tested prevented substrate dehydration, improving lipase production. In this work, the important role of Triton X-100 on lipase extraction from the fermented solid substrate has been shown. A final lipase activity of 223 ± 5 U g -1 (dry basis) was obtained after 7 days of fermentation.

  18. Root Cause Assessment of Pressure Drop Rise of a Packed Bed of Lithium Hydroxide in the International Space Station Trace Contaminant Control System

    Science.gov (United States)

    Aguilera, Tatiana; Perry, Jay L.

    2009-01-01

    The trace contaminant control system (TCCS) located in the International Space Station s (ISS) U.S. laboratory module employs physical adsorption, thermal catalytic oxidation, and chemical adsorption to remove trace chemical contamination produced by equipment offgassing and anthropogenic sources from the cabin atmosphere. The chemical adsorption stage, consisting of a packed bed of granular lithium hydroxide (LiOH), is located after the thermal catalytic oxidation stage and is designed to remove acid gas byproducts that may be formed in the upstream oxidation stage. While in service on board the ISS, the LiOH bed exhibited a change in flow resistance that leading to flow control difficulties in the TCCS. Post flight evaluation revealed LiOH granule size attrition among other changes. An experimental program was employed to investigate mechanisms hypothesized to contribute to the change in the packed bed s flow resistance. Background on the problem is summarized, including a discussion of likely mechanisms. The experimental program is described, results are presented, and implications for the future are discussed.

  19. Dry reforming of methane via plasma-catalysis: influence of the catalyst nature supported on alumina in a packed-bed DBD configuration

    Science.gov (United States)

    Brune, L.; Ozkan, A.; Genty, E.; Visart de Bocarmé, T.; Reniers, F.

    2018-06-01

    These days, the consideration of CO2 as a feedstock has become the subject of more interest. The reutilization of CO2 is already possible via cold plasma techniques operating at atmospheric pressure. A promising technology is the dielectric barrier discharge (DBD). In most cases DBDs exhibit a low energy efficiency for CO2 conversion. However, several routes can be used to increase this efficiency and hence, the product formation. One of these routes is the packed-bed DBD configuration with porous beads inside the gap of the DBD, which also allows the coupling of plasma with catalysis. Catalysts can be introduced in such a configuration to exploit the synergistic effect between plasma and catalytically active surfaces, leading to a more efficient process. In this article, the dry reforming of methane (DRM) is studied, which aims to convert both CO2 and CH4, another greenhouse gas, at the same time. The conversions and energy costs of the DRM process are investigated and compared in both the packed-bed DBD configurations containing catalysts (Co, Cu or Ni) and the classical DBD. The change in filamentary behavior is studied in detail and correlated with the obtained conversions using gas chromatography, mass spectrometry and using an oscilloscope. A characterization of the catalysts on the beads is also carried out. Both the CO2 and CH4 conversions are clearly increased with the plasma-catalysis. Moreover, CH4 conversions as high as 90% can be obtained in certain conditions with copper catalysts.

  20. Enhancing the Bioconversion of Winery and Olive Mill Waste Mixtures into Lignocellulolytic Enzymes and Animal Feed by Aspergillus uvarum Using a Packed-Bed Bioreactor.

    Science.gov (United States)

    Salgado, José Manuel; Abrunhosa, Luís; Venâncio, Armando; Domínguez, José Manuel; Belo, Isabel

    2015-10-28

    Wineries and olive oil industries are dominant agro-industrial activities in southern European regions. Olive pomace, exhausted grape marc, and vine shoot trimmings are lignocellulosic residues generated by these industries, which could be valued biotechnologically. In the present work these residues were used as substrate to produce cellulases and xylanases through solid-state fermentation using Aspergillus uvarum MUM 08.01. For that, two factorial designs (3(2)) were first planned to optimize substrate composition, temperature, and initial moisture level. Subsequently, the kinectics of cellulolytic enzyme production, fungal growth, and fermented solid were characterized. Finally, the process was performed in a packed-bed bioreactor. The results showed that cellulase activity improved with the optimization processes, reaching 33.56 U/g, and with the packed-bed bioreactor aeration of 0.2 L/min, reaching 38.51 U/g. The composition of fermented solids indicated their potential use for animal feed because cellulose, hemicellulose, lignin, and phenolic compounds were partially degraded 28.08, 10.78, 13.3, and 28.32%, respectively, crude protein was increased from 8.47 to 17.08%, and the mineral contents meet the requirements of main livestock.

  1. Continuous production of biohythane from hydrothermal liquefied cornstalk biomass via two-stage high-rate anaerobic reactors.

    Science.gov (United States)

    Si, Bu-Chun; Li, Jia-Ming; Zhu, Zhang-Bing; Zhang, Yuan-Hui; Lu, Jian-Wen; Shen, Rui-Xia; Zhang, Chong; Xing, Xin-Hui; Liu, Zhidan

    2016-01-01

    Biohythane production via two-stage fermentation is a promising direction for sustainable energy recovery from lignocellulosic biomass. However, the utilization of lignocellulosic biomass suffers from specific natural recalcitrance. Hydrothermal liquefaction (HTL) is an emerging technology for the liquefaction of biomass, but there are still several challenges for the coupling of HTL and two-stage fermentation. One particular challenge is the limited efficiency of fermentation reactors at a high solid content of the treated feedstock. Another is the conversion of potential inhibitors during fermentation. Here, we report a novel strategy for the continuous production of biohythane from cornstalk through the integration of HTL and two-stage fermentation. Cornstalk was converted to solid and liquid via HTL, and the resulting liquid could be subsequently fed into the two-stage fermentation systems. The systems consisted of two typical high-rate reactors: an upflow anaerobic sludge blanket (UASB) and a packed bed reactor (PBR). The liquid could be efficiently converted into biohythane via the UASB and PBR with a high density of microbes at a high organic loading rate. Biohydrogen production decreased from 2.34 L/L/day in UASB (1.01 L/L/day in PBR) to 0 L/L/day as the organic loading rate (OLR) of the HTL liquid products increased to 16 g/L/day. The methane production rate achieved a value of 2.53 (UASB) and 2.54 L/L/day (PBR), respectively. The energy and carbon recovery of the integrated HTL and biohythane fermentation system reached up to 79.0 and 67.7%, respectively. The fermentation inhibitors, i.e., 5-hydroxymethyl furfural (41.4-41.9% of the initial quantity detected) and furfural (74.7-85.0% of the initial quantity detected), were degraded during hydrogen fermentation. Compared with single-stage fermentation, the methane process during two-stage fermentation had a more efficient methane production rate, acetogenesis, and COD removal. The microbial distribution

  2. Biofilm reactors for industrial bioconversion processes: employing potential of enhanced reaction rates

    Directory of Open Access Journals (Sweden)

    Karcher Patrick

    2005-08-01

    Full Text Available Abstract This article describes the use of biofilm reactors for the production of various chemicals by fermentation and wastewater treatment. Biofilm formation is a natural process where microbial cells attach to the support (adsorbent or form flocs/aggregates (also called granules without use of chemicals and form thick layers of cells known as "biofilms." As a result of biofilm formation, cell densities in the reactor increase and cell concentrations as high as 74 gL-1 can be achieved. The reactor configurations can be as simple as a batch reactor, continuous stirred tank reactor (CSTR, packed bed reactor (PBR, fluidized bed reactor (FBR, airlift reactor (ALR, upflow anaerobic sludge blanket (UASB reactor, or any other suitable configuration. In UASB granular biofilm particles are used. This article demonstrates that reactor productivities in these reactors have been superior to any other reactor types. This article describes production of ethanol, butanol, lactic acid, acetic acid/vinegar, succinic acid, and fumaric acid in addition to wastewater treatment in the biofilm reactors. As the title suggests, biofilm reactors have high potential to be employed in biotechnology/bioconversion industry for viable economic reasons. In this article, various reactor types have been compared for the above bioconversion processes.

  3. Biofilm reactors for industrial bioconversion processes: employing potential of enhanced reaction rates

    Science.gov (United States)

    Qureshi, Nasib; Annous, Bassam A; Ezeji, Thaddeus C; Karcher, Patrick; Maddox, Ian S

    2005-01-01

    This article describes the use of biofilm reactors for the production of various chemicals by fermentation and wastewater treatment. Biofilm formation is a natural process where microbial cells attach to the support (adsorbent) or form flocs/aggregates (also called granules) without use of chemicals and form thick layers of cells known as "biofilms." As a result of biofilm formation, cell densities in the reactor increase and cell concentrations as high as 74 gL-1 can be achieved. The reactor configurations can be as simple as a batch reactor, continuous stirred tank reactor (CSTR), packed bed reactor (PBR), fluidized bed reactor (FBR), airlift reactor (ALR), upflow anaerobic sludge blanket (UASB) reactor, or any other suitable configuration. In UASB granular biofilm particles are used. This article demonstrates that reactor productivities in these reactors have been superior to any other reactor types. This article describes production of ethanol, butanol, lactic acid, acetic acid/vinegar, succinic acid, and fumaric acid in addition to wastewater treatment in the biofilm reactors. As the title suggests, biofilm reactors have high potential to be employed in biotechnology/bioconversion industry for viable economic reasons. In this article, various reactor types have been compared for the above bioconversion processes. PMID:16122390

  4. Biofilm reactors for industrial bioconversion processes: employing potential of enhanced reaction rates.

    Science.gov (United States)

    Qureshi, Nasib; Annous, Bassam A; Ezeji, Thaddeus C; Karcher, Patrick; Maddox, Ian S

    2005-08-25

    This article describes the use of biofilm reactors for the production of various chemicals by fermentation and wastewater treatment. Biofilm formation is a natural process where microbial cells attach to the support (adsorbent) or form flocs/aggregates (also called granules) without use of chemicals and form thick layers of cells known as "biofilms." As a result of biofilm formation, cell densities in the reactor increase and cell concentrations as high as 74 gL(-1) can be achieved. The reactor configurations can be as simple as a batch reactor, continuous stirred tank reactor (CSTR), packed bed reactor (PBR), fluidized bed reactor (FBR), airlift reactor (ALR), upflow anaerobic sludge blanket (UASB) reactor, or any other suitable configuration. In UASB granular biofilm particles are used. This article demonstrates that reactor productivities in these reactors have been superior to any other reactor types. This article describes production of ethanol, butanol, lactic acid, acetic acid/vinegar, succinic acid, and fumaric acid in addition to wastewater treatment in the biofilm reactors. As the title suggests, biofilm reactors have high potential to be employed in biotechnology/bioconversion industry for viable economic reasons. In this article, various reactor types have been compared for the above bioconversion processes.

  5. Adaptive Controller Design for Continuous Stirred Tank Reactor

    OpenAIRE

    K. Prabhu; V. Murali Bhaskaran

    2014-01-01

    Continues Stirred Tank Reactor (CSTR) is an important issue in chemical process and a wide range of research in the area of chemical engineering. Temperature Control of CSTR has been an issue in the chemical control engineering since it has highly non-linear complex equations. This study presents problem of temperature control of CSTR with the adaptive Controller. The Simulation is done in MATLAB and result shows that adaptive controller is an efficient controller for temperature control of C...

  6. Terminal sliding mode control for continuous stirred tank reactor

    OpenAIRE

    Zhao, D.; Zhu, Q.; Dubbeldam, J.

    2015-01-01

    A continuous stirred tank reactor (CSTR) is a typical example of chemical industrial equipment, whose dynamics represent an extensive class of second order nonlinear systems. It has been witnessed that designing a good control algorithm for the CSTR is very challenging due to the high complexity. The two difficult issues in CSTR control are state estimation and external disturbance attenuation. In general, in industrial process control a fast and robust response is essential. Driven by these ...

  7. Optimization and control of a continuous polymerization reactor

    Directory of Open Access Journals (Sweden)

    L. A. Alvarez

    2012-12-01

    Full Text Available This work studies the optimization and control of a styrene polymerization reactor. The proposed strategy deals with the case where, because of market conditions and equipment deterioration, the optimal operating point of the continuous reactor is modified significantly along the operation time and the control system has to search for this optimum point, besides keeping the reactor system stable at any possible point. The approach considered here consists of three layers: the Real Time Optimization (RTO, the Model Predictive Control (MPC and a Target Calculation (TC that coordinates the communication between the two other layers and guarantees the stability of the whole structure. The proposed algorithm is simulated with the phenomenological model of a styrene polymerization reactor, which has been widely used as a benchmark for process control. The complete optimization structure for the styrene process including disturbances rejection is developed. The simulation results show the robustness of the proposed strategy and the capability to deal with disturbances while the economic objective is optimized.

  8. Continuous synthesis of glucoamylase by immobilized fungal mycelium of Aspergillus niger

    Energy Technology Data Exchange (ETDEWEB)

    Abraham, T.E.; Jamuna, R.; Bansilal, C.V.; Ramakrishna, S.V. (Regional Research Lab., Trivandrum (India))

    1991-03-01

    The extracellular glucoamylase enzyme (EC 3.2.1.3) was synthesized continuously by the immobilized mycelial fragments of A. niger. Of the several polymeric matrices attempted for immobilization k-carrageenan and alginate were found to be the most effective. However, the enzyme activity exhibited by the immobilized mycelia (I.M.) was 15-20% lower than that of free cells under batch conditions. The immobilized cells have retained nearly the same enzymatic activity (120IU/g of I.M.) for 6 repeated batches and thereafter decline in activity was noticed. An aerated packed bed reactor with I.M. was operated continuously for 360 h. The volumetric productivity of the reactor was 1600IU/L/h for 192 h and reduced to 25% in 360 h. (orig.).

  9. Full-Scale Continuous Mini-Reactor Setup for Heterogeneous Grignard Alkylation of a Pharmaceutical Intermediate

    DEFF Research Database (Denmark)

    Pedersen, Michael Jønch; Holm, Thomas; Rahbek, Jesper P.

    2013-01-01

    A reactor setup consisting of two reactors in series has been implemented for a full-scale, heterogeneous Grignard alkylation. Solutions pass from a small filter reactor into a static mixer reactor with multiple side entries, thus combining continuous stirred tank reactor (CSTR) and plug flow...

  10. Hydrothermal Processing of Macroalgal Feedstocks in Continuous-Flow Reactors

    Energy Technology Data Exchange (ETDEWEB)

    Elliott, Douglas C.; Hart, Todd R.; Neuenschwander, Gary G.; Rotness, Leslie J.; Roesijadi, Guri; Zacher, Alan H.; Magnuson, Jon K.

    2014-02-03

    Wet macroalgal slurries have been converted into a biocrude by hydrothermal liquefaction (HTL) in a bench-scale continuous-flow reactor system. Carbon conversion to a gravity-separable oil product of 58.8% was accomplished at relatively low temperature (350 °C) in a pressurized (subcritical liquid water) environment (20 MPa) when using feedstock slurries with a 21.7% concentration of dry solids. As opposed to earlier work in batch reactors reported by others, direct oil recovery was achieved without the use of a solvent, and biomass trace mineral components were removed by processing steps so that they did not cause processing difficulties. In addition, catalytic hydrothermal gasification (CHG) was effectively applied for HTL byproduct water cleanup and fuel gas production from water-soluble organics. Conversion of 99.2% of the carbon left in the aqueous phase was demonstrated. Finally, as a result, high conversion of macroalgae to liquid and gas fuel products was found with low levels of residual organic contamination in byproduct water. Both process steps were accomplished in continuous-flow reactor systems such that design data for process scale-up was generated.

  11. Investigation of a submerged membrane reactor for continuous biomass hydrolysis

    Energy Technology Data Exchange (ETDEWEB)

    Malmali, Mohammadmahdi; Stickel, Jonathan; Wickramasinghe, S. Ranil

    2015-10-01

    Enzymatic hydrolysis of cellulose is one of the most costly steps in the bioconversion of lignocellulosic biomass. Use of a submerged membrane reactor has been investigated for continuous enzymatic hydrolysis of cellulose thus allowing for greater use of the enzyme compared to a batch process. Moreover, the submerged 0.65 μm polyethersulfone microfiltration membrane avoids the need to pump a cellulose slurry through an external loop. Permeate containing glucose is withdrawn at pressures slightly below atmospheric pressure. The membrane rejects cellulose particles and cellulase enzyme bound to cellulose. Our proof-of-concept experiments have been conducted using a modified, commercially available membrane filtration cell under low fluxes around 75 L/(m2 h). The operating flux is determined by the rate of glucose production. Maximizing the rate of glucose production involves optimizing mixing, reactor holding time, and the time the feed is held in the reactor prior to commencement of membrane filtration and continuous operation. When we maximize glucose production rates it will require that we operate it at low glucose concentration in order to minimize the adverse effects of product inhibition. Consequently practical submerged membrane systems will require a combined sugar concentration step in order to concentrate the product sugar stream prior to fermentation.

  12. A cubic autocatalytic reaction in a continuous stirred tank reactor

    Energy Technology Data Exchange (ETDEWEB)

    Yakubu, Aisha Aliyu; Yatim, Yazariah Mohd [School of Mathematical Sciences, Universiti Sains Malaysia, 11800 USM, Penang Malaysia (Malaysia)

    2015-10-22

    In the present study, the dynamics of the cubic autocatalytic reaction model in a continuous stirred tank reactor with linear autocatalyst decay is studied. This model describes the behavior of two chemicals (reactant and autocatalyst) flowing into the tank reactor. The behavior of the model is studied analytically and numerically. The steady state solutions are obtained for two cases, i.e. with the presence of an autocatalyst and its absence in the inflow. In the case with an autocatalyst, the model has a stable steady state. While in the case without an autocatalyst, the model exhibits three steady states, where one of the steady state is stable, the second is a saddle point while the last is spiral node. The last steady state losses stability through Hopf bifurcation and the location is determined. The physical interpretations of the results are also presented.

  13. Continuous hyperpolarization with parahydrogen in a membrane reactor

    Science.gov (United States)

    Lehmkuhl, Sören; Wiese, Martin; Schubert, Lukas; Held, Mathias; Küppers, Markus; Wessling, Matthias; Blümich, Bernhard

    2018-06-01

    Hyperpolarization methods entail a high potential to boost the sensitivity of NMR. Even though the "Signal Amplification by Reversible Exchange" (SABRE) approach uses para-enriched hydrogen, p-H2, to repeatedly achieve high polarization levels on target molecules without altering their chemical structure, such studies are often limited to batch experiments in NMR tubes. Alternatively, this work introduces a continuous flow setup including a membrane reactor for the p-H2, supply and consecutive detection in a 1 T NMR spectrometer. Two SABRE substrates pyridine and nicotinamide were hyperpolarized, and more than 1000-fold signal enhancement was found. Our strategy combines low-field NMR spectrometry and a membrane flow reactor. This enables precise control of the experimental conditions such as liquid and gas pressures, and volume flow for ensuring repeatable maximum polarization.

  14. Design of Continuous Reactor Systems for API Production

    DEFF Research Database (Denmark)

    Pedersen, Michael Jønch

    -scale production equipment enabled complete replacement of the existing batch production of this intermediate. The crowning achievement in this work was the realization of continuous laboratory reactor setups capable of manufacturing the entire GMP portion of the synthesis of melitracen HCl at H. Lundbeck A....... The methodology provides suggestions on when and how decisions should be made on continuous production methods for Grignard chemistry within pharmaceutical manufacturing. Physicochemical properties, such as solubility, were found to be critical. However, from a business perspective, issues such as the current......The pharmaceutical industry has experienced many changes over the last few decades. Continuous production has been promoted as one of the more promising methods for making the industry more efficient and sustainable. The primary focus of this thesis is on the performance of Grignard chemistry...

  15. Biodegradation of the herbicide Diuron in a packed bed channel and a double biobarrier with distribution of oxygenated liquid by airlift devices: influence of oxygen limitation.

    Science.gov (United States)

    Castañón-González, J Humberto; Galíndez-Mayer, Juvencio; Ruiz-Ordaz, Nora; Rocha-Martínez, Lizeth; Peña-Partida, José Carlos; Marrón-Montiel, Erick; Santoyo-Tepole, Fortunata

    2016-01-25

    From agricultural soils, where the herbicide Diuron has been frequently applied, a microbial community capable of degrading Diuron and 3,4-dichloroaniline was obtained. The volumetric rates and degradation efficiencies of Diuron and 3,4-DCA were evaluated in two distinct biofilm reactors, which differ in their operating conditions. One is a horizontal fixed bed reactor; plug-flow operated (PF-PBC) with severe limitation of oxygen. In this reactor, the air was supplied to an equalizer reservoir at the start of the PF-PBC reactor. The other is a compartmentalized aerobic biobarrier with internal recirculation of liquid aerated through airlift devices (ALB), continuously or intermittently operated. Both reactors were inoculated with a microbial community capable of degrading Diuron, isolated from a sugarcane field. In the oxygen-limited PF-PBC reactor, 3,4-DCA accumulation was detected, mainly in the middle zone of the packed channel. On the contrary, in the fully aerobic ALB reactor, minimal accumulation of catabolic byproducts was detected, and high Diuron removal efficiencies and removal rates were obtained when it was continuously operated in steady-state conditions. Additionally, the influence of oxygen limitation on the kinetic behavior of the PF-PBC reactor was determined, and a method to estimate the local removal rates of Diuron RV,CD along the plug-flow channel is described. It was observed that the local values of the instantaneous removal rate of Diuron dCD/dt are high in the aerobic region of the PF-PBC reactor; but, suddenly decay in the reactor zones limited by dissolved oxygen. Copyright © 2015 Elsevier B.V. All rights reserved.

  16. Increased performance of continuous stirred tank reactor with calcium supplementation

    Energy Technology Data Exchange (ETDEWEB)

    Yuan, Zhuliang; Yang, Haijun; Zhi, Xiaohua; Shen, Jianquan [Beijing National Laboratory for Molecular Sciences (BNLMS), New Materials Laboratory, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190 (China)

    2010-04-15

    Continuous biohydrogen production with calcium supplementation at low hydraulic retention time (HRT) in a continuous stirred tank reactor (CSTR) was studied to maximize the hydrogen productivity of anaerobic mixed cultures. After stable operations at HRT of 8-4 h, the bioreactor became unstable when the HRT was lowered to 2 h. Supplementation of 100 mg/L calcium at HRT 2 h improved the operation stability through enhancement of cell retention with almost two-fold increase in cell density than that without calcium addition. Hydrogen production rate and hydrogen yield reached 24.5 L/d/L and 3.74 mol H{sub 2}/mol sucrose, respectively, both of which were the highest values our group have ever achieved. The results showed that calcium supplementation can be an effective way to improve the performance of CSTR at low HRT. (author)

  17. Continuous cryopump for steady state mirror fusion reactors

    International Nuclear Information System (INIS)

    Batzer, T.H.; Call, W.R.

    1983-01-01

    The characteristics of mirror fusion reactors, i.e., steady state operation, a low neutral gas density, and a large gas throughput require unique vacuum pumping capabilities. One approach that appears to meet these requirements is a liquid helium-cooled cryopump system in which a fixed portion can be isolated and degassed while the remainder continues to pump. The time to degas a rotating, fixed portion of the pumping area and the ratio of that area to the total area fixes the gas inventory in the chamber. It follows that the active pump area maintains the required neutral gas density and the time-averaged degassing rate equals the gas throughput. We have built such a cryopump whereby the gas condensed (deuterium) on the liquid helium-cooled panel can be transferred to a collector pump and subsequently to an exterior mechanical pump and exhausted. At panel loadings as high as 0.55 Torr-/lcm 2 the gas leakage during degassing is less than 8% and the degassing time is less than 10 min. Scaling to reactor size appears to be feasible

  18. PDBD with continuous liquids flows in a discharge reactor

    International Nuclear Information System (INIS)

    Rodríguez-Méndez, B G; Gutiérrez-León, D G; López-Callejas, R; Valencia-Alvarado, R; Muñoz-Castro, A E; Mercado-Cabrera, A; Peña-Eguiluz, R; Belman-Flores, J M; De la Piedad-Beneitez, A

    2015-01-01

    This paper presents the design, construction and testing of a cylindrical pulsed dielectric barrier discharge (PDBD) reactor aimed to microbiological elimination of Escherichia coli ATCC 8739 bacteria. In the reactor, water flowed continuously and to countercurrent an oxygen gas was injected. The water pumping was carried out with a peristaltic pump type, stainless steel and aluminum constructed, and water was recirculated through norprene tubing. The considered parameters in order to promote energetic efficiency were: the residence time of the water contaminated with bacteria, flow rate of the liquid, shape and material used to build electrodes and dielectric, pressure, and gas injection flow rate. The pulsed power supply parameters are featured by 25-30 kV high voltage, 500 Hz frequency and 30 μs width. The outcome elimination of E. coli bacteria at 10 3 , 10 4 and 10 6 CFU/mL concentrations reached an efficiency over 0.5 log-order in absence of oxygen; while >2 log-orders when oxygen gas was injected during the process. (paper)

  19. The assembly and use of continuous flow systems for chemical synthesis.

    Science.gov (United States)

    Britton, Joshua; Jamison, Timothy F

    2017-11-01

    The adoption of and opportunities in continuous flow synthesis ('flow chemistry') have increased significantly over the past several years. Continuous flow systems provide improved reaction safety and accelerated reaction kinetics, and have synthesised several active pharmaceutical ingredients in automated reconfigurable systems. Although continuous flow platforms are commercially available, systems constructed 'in-lab' provide researchers with a flexible, versatile, and cost-effective alternative. Herein, we describe the assembly and use of a modular continuous flow apparatus from readily available and affordable parts in as little as 30 min. Once assembled, the synthesis of a sulfonamide by reacting 4-chlorobenzenesulfonyl chloride with dibenzylamine in a single reactor coil with an in-line quench is presented. This example reaction offers the opportunity to learn several important skills including reactor construction, charging of a back-pressure regulator, assembly of stainless-steel syringes, assembly of a continuous flow system with multiple junctions, and yield determination. From our extensive experience of single-step and multistep continuous flow synthesis, we also describe solutions to commonly encountered technical problems such as precipitation of solids ('clogging') and reactor failure. Following this protocol, a nonspecialist can assemble a continuous flow system from reactor coils, syringes, pumps, in-line liquid-liquid separators, drying columns, back-pressure regulators, static mixers, and packed-bed reactors.

  20. Influence of accuracy of thermal property data of a phase change material on the result of a numerical model of a packed bed latent heat storage with spheres

    Energy Technology Data Exchange (ETDEWEB)

    Arkar, C.; Medved, S. [University of Ljubljana, Faculty of Mechanical Engineering, Askerceva 6, 1000 Ljubljana (Slovenia)

    2005-11-01

    With the integration of latent-heat thermal energy storage (LHTES) in building services, solar energy and the coldness of ambient air can be efficiently used to reduce the energy used for heating and cooling and to improve the level of living comfort. For this purpose, a cylindrical LHTES containing spheres filled with paraffin was developed. For the proper modelling of the LHTES thermal response the thermal properties of the phase change material (PCM) must be accurately known. This article presents the influence of the accuracy of thermal property data of the PCM on the result of the prediction of the LHTES's thermal response. A packed bed numerical model was adapted to take into account the non-uniformity of the PCM's porosity and the fluid's velocity. Both are the consequence of a small tube-to-sphere diameter ratio, which is characteristic of the developed LHTES. The numerical model can also take into account the PCM's temperature-dependent thermal properties. The temperature distribution of the latent heat of the paraffin (RT20) used in the experiment in the form of apparent heat capacity was determined using a differential scanning calorimeter (DSC) at different heating and cooling rates. A comparison of the numerical and experimental results confirmed our hypothesis relating to the important role that the PCM's thermal properties play, especially during slow running processes, which are characteristic for our application.

  1. Dripping and evolution behavior of primary slag bearing TiO2 through the coke packed bed in a blast-furnace hearth

    Science.gov (United States)

    Liu, Yan-xiang; Zhang, Jian-liang; Wang, Zhi-yu; Jiao, Ke-xin; Zhang, Guo-hua; Chou, Kuo-chih

    2017-02-01

    To investigate the flow of primary slag bearing TiO2 in the cohesive zone of blast furnaces, experiments were carried out based on the laboratory-scale packed bed systems. It is concluded that the initial temperature of slag dripping increases with decreasing FeO content and increasing TiO2 content. The slag holdup decreases when the FeO content is in the range of 5wt%-10wt%, whereas it increases when the FeO content exceeds 10wt%. Meanwhile, the slag holdup decreases when the TiO2 content increases from 5wt% to 10wt% but increases when the TiO2 content exceeds 10wt%. Moreover, slag/coke interface analysis shows that the reaction between FeO and TiO2 occurs between the slag and the coke. The slag/coke interface is divided into three layers: slag layer, iron-rich layer, and coke layer. TiO2 in the slag is reduced by carbon, and the generated Ti diffuses into iron.

  2. Continuous-flow solar UVB disinfection reactor for drinking water.

    Science.gov (United States)

    Mbonimpa, Eric Gentil; Vadheim, Bryan; Blatchley, Ernest R

    2012-05-01

    Access to safe, reliable sources of drinking water is a long-standing problem among people in developing countries. Sustainable solutions to these problems often involve point-of-use or community-scale water treatment systems that rely on locally-available resources and expertise. This philosophy was used in the development of a continuous-flow, solar UVB disinfection system. Numerical modeling of solar UVB spectral irradiance was used to define temporal variations in spectral irradiance at several geographically-distinct locations. The results of these simulations indicated that a solar UVB system would benefit from incorporation of a device to amplify ambient UVB fluence rate. A compound parabolic collector (CPC) was selected for this purpose. Design of the CPC was based on numerical simulations that accounted for the shape of the collector and reflectance. Based on these simulations, a prototype CPC was constructed using materials that would be available and inexpensive in many developing countries. A UVB-transparent pipe was positioned in the focal area of the CPC; water was pumped through the pipe to allow exposure of waterborne microbes to germicidal solar UVB radiation. The system was demonstrated to be effective for inactivation of Escherichia coli, and DNA-weighted UV dose was shown to govern reactor performance. The design of the reactor is expected to scale linearly, and improvements in process performance (relative to results from the prototype) can be expected by use of larger CPC geometry, inclusion of better reflective materials, and application in areas with greater ambient solar UV spectral irradiance than the location of the prototype tests. The system is expected to have application for water treatment among communities in (developing) countries in near-equatorial and tropical locations. It may also have application for disaster relief or military field operations, as well as in water treatment in areas of developed countries that receive

  3. Mathematical modelling of a continuous biomass torrefaction reactor: TORSPYDTM column

    International Nuclear Information System (INIS)

    Ratte, J.; Fardet, E.; Mateos, D.; Hery, J.-S.

    2011-01-01

    Torrefaction is a soft thermal process usually applied to cocoa or coffee beans to obtain the Maillard reaction to produce aromatics and enhance the flavour. In the case of biomass the main interest of torrefaction it is to break the fibers. To do so, Thermya company has developed and patented a biomass torrefaction/depolymerisation process called TORSPYD TM . It is a homogeneous 'soft' thermal process that takes place in an inert atmosphere. The process progressively eliminates the biomass water content transforms a portion of the biomass organic matter and breaks the biomass structure by depolymerisation of the fibers. This produces a high performance solid fuel, called Biocoal, which offers a range of benefits over and above that of normal biomass fuel. To develop such a process, this company has developed two main tools: - a continuous torrefaction laboratory pilot with a capacity to produce 3 - 8 kg/h of torrefied biomass; - a mathematical model dedicated to the design and optimisation of the TORSPYD reactor. The mathematical model is able to describe the chemical and physical processes that take place in the torrefaction column at two different scales, namely: the particle, and the surrounding gas. The model enables the gas temperature profiles inside the column to be predicted, and the results of the model are then validated through experiment in the laboratory pilot. The model also allows us to estimate the thermal power necessary to torrefy any type of biomass for a given moisture content. -- Highlights: → We model a patented torrefaction/depolymerisation biomass process: TORPSPYD. → We compare simulated results to experimental data obtained from our torrefaction pilot plant. → We describe phenomenon that occurs in our torrefaction reactor and discuss about the influence of moisture of the input biomass.

  4. Incorporation of statistical distribution of particle properties in chemical reactor design and operation: the cooled tubular reactor

    NARCIS (Netherlands)

    Wijngaarden, R.J.; Westerterp, K.R.

    1992-01-01

    Pellet heat and mass transfer coefficients inside packed beds do not have definite deterministic values, but are stochastic quantities with a certain distribution. Here, a method is presented to incorporate the stochastic distribution of pellet properties in reactor design and operation models. The

  5. CONTINUOUS PRODUCTION OF HYDROXYPROPYL STARCH IN A STATIC MIXER REACTOR

    NARCIS (Netherlands)

    LAMMERS, G; STAMHUIS, EJ; BEENACKERS, AACM

    A novel type of reactor for the chemical derivatization of starch pastes is presented. The design is based on the application of static mixers. The reactor shows excellent plug flow behaviour with a Peclet number of about 100. The viscosity behaviour of concentrated starch pastes in the static mixer

  6. Adsorption of Reactive Red 2 from aqueous solutions using Fe{sub 3}O{sub 4} nanoparticles prepared by co-precipitation in a rotating packed bed

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Chia-Chang, E-mail: higee@mail.cgu.edu.tw [Department of Chemical and Materials Engineering, Chang Gung University, Taoyuan, Taiwan, ROC (China); Lin, Yu-Shung [Department of Chemical and Materials Engineering, Chang Gung University, Taoyuan, Taiwan, ROC (China); Ho, Jui-Min [Graduate Institute of Biochemical and Biomedical Engineering, Chang Gung University, Taoyuan, Taiwan, ROC (China)

    2016-05-05

    A rotating packed bed (RPB) that was operated at a rotating speed of 1800 rpm with liquid flow rates of 0.5 L/min was used to prepare Fe{sub 3}O{sub 4} nanoparticles (RPB-Fe{sub 3}O{sub 4}). The RPB-Fe{sub 3}O{sub 4} had a smaller average size and a narrower size distribution than the Fe{sub 3}O{sub 4} that was obtained from Aldrich, and so had a greater capacity to adsorb RR2. The effects of pH, Fe{sub 3}O{sub 4} dosage, initial RR2 concentration, and temperature on the adsorption of RR2 were examined experimentally using RPB-Fe{sub 3}O{sub 4}. A thermodynamic study revealed that the adsorption process was spontaneous and exothermic. The adsorption behavior was more consistent with the Langmuir model than with the Freundlich model, and the maximum adsorption capacity was 97.8 mg/g. At pH 3, 25 °C, an Fe{sub 3}O{sub 4} dosage of 0.30 g/L, and an initial RR2 concentration of 10 mg/L, RPB-Fe{sub 3}O{sub 4} effectively adsorbed RR2 with a removal efficiency of approximately 95% in 10 min. These promising results clearly reveal the potential of RPB-Fe{sub 3}O{sub 4} for use in the effective removal of dyes from aqueous solutions. - Highlights: • A novel magnetic adsorbent (Fe{sub 3}O{sub 4} nanoparticles) was prepared in RPB. • 95% removal of RR2 was achieved in 10 min using Fe{sub 3}O{sub 4} nanoparticles. • This investigation provides a novel treatment of dye-contaminated wastewater.

  7. Continuous Flow Aerobic Alcohol Oxidation Reactions Using a Heterogeneous Ru(OH)x/Al2O3 Catalyst

    Science.gov (United States)

    2015-01-01

    Ru(OH)x/Al2O3 is among the more versatile catalysts for aerobic alcohol oxidation and dehydrogenation of nitrogen heterocycles. Here, we describe the translation of batch reactions to a continuous-flow method that enables high steady-state conversion and single-pass yields in the oxidation of benzylic alcohols and dehydrogenation of indoline. A dilute source of O2 (8% in N2) was used to ensure that the reaction mixture, which employs toluene as the solvent, is nonflammable throughout the process. A packed bed reactor was operated isothermally in an up-flow orientation, allowing good liquid–solid contact. Deactivation of the catalyst during the reaction was modeled empirically, and this model was used to achieve high conversion and yield during extended operation in the aerobic oxidation of 2-thiophene methanol (99+% continuous yield over 72 h). PMID:25620869

  8. Continuous-Flow Monolithic Silica Microreactors with Arenesulphonic Acid Groups: Structure–Catalytic Activity Relationships

    Directory of Open Access Journals (Sweden)

    Agnieszka Ciemięga

    2017-08-01

    Full Text Available The performance of monolithic silica microreactors activated with sulphonic acid groups and a packed bed reactor with Amberlyst 15 resin were compared in the esterification of acetic acid with n-butanol. The monolithic microreactors were made of single silica rods with complex pore architecture, differing in the size of mesopores, and in particular, flow-through macropores which significantly affected the flow characteristic of the continuous system. The highest ester productivity of 105.2 mol·molH+−1·h−1 was achieved in microreactor M1 with the largest porosity, characterized by a total pore volume of 4 cm3·g−1, mesopores with 20 nm diameter, and large flow-through macropores 30–50 μm in size. The strong impact of the permeability of the monoliths on a reaction kinetics was shown.

  9. Summary of detection, location, and characterization capabilities of AE for continuous monitoring of cracks in reactors

    International Nuclear Information System (INIS)

    Hutton, P.H.; Kurtz, R.J.; Friesel, M.A.; Pappas, R.A.; Skorpik, J.R.; Dawson, J.F.

    1984-10-01

    The objective of the program is to develop acoustic emission (AE) methods for continuous monitoring of reactor pressure boundaries to detect and evaluate crack growth. The approach involves three phases: develop relationships to identify crack growth AE signals and to use identified crack growth AE data to estimate flaw severity; evaluate and refine AE/flaw relationships through fatigue testing a heavy section vessel under simulated reactor conditions; and demonstrate continuous AE monitoring on a nuclear power reactor system

  10. A modular continuous flow reactor system for the selective bio-oxidation of iron and precipitation of schwertmannite from mine-impacted waters.

    Science.gov (United States)

    Hedrich, Sabrina; Johnson, D Barrie

    2012-02-01

    A novel modular bioremediation system which facilitates the selective removal of soluble iron from extremely acidic (pH ∼2) metal-rich wastewaters by ferrous iron oxidation and selective precipitation of the ferric iron produced is described. In the first of the three modules, rapid ferrous iron oxidation was mediated by the recently-characterized iron-oxidizing autotrophic acidophile, "Ferrovum myxofaciens", which grew as long "streamers" within the reactor. Over 90% of the iron present in influent test liquors containing 280mg/L iron was oxidized at a dilution rate of 0.41h(-1), in a proton-consuming reaction. The ferric iron-rich solutions produced were pumped into a second reactor where controlled addition of sodium hydroxide caused the water pH to increase to 3.5 and ferric iron to precipitate as the mineral schwertmannite. Addition of a flocculating agent promoted rapid aggregation and settling of the fine-grain schwertmannite particles. A third passive module (a packed-bed bioreactor, also inoculated with "Fv. myxofaciens") acted as a polishing reactor, lowering soluble iron concentrations in the processed water to iron from a synthetic acidic (pH 2.1) mine water that contained soluble aluminum, copper, manganese and zinc in addition to iron. Schwertmannite was again produced, with little or no co-precipitation of other metals. Copyright © 2011 Elsevier Ltd. All rights reserved.

  11. Study of the population dynamics of a mixed bacterial culture able to degrade cyanuric acid in a packed bed reactor, using RAPD (Random amplification of polymorphic DNA) technique

    International Nuclear Information System (INIS)

    Galindez-Najera, S.; Llamas-Martinez, M.; Ahuatzi-Chacon, D.; Ruiz-Ordaz, N.; Galindez-Mayer, C. J.

    2009-01-01

    Cyanuric acid is a biodegradation byproduct of triazinic compounds. Because of its low carbon to nitrogen ratio, a complementary carbon source is usually needed for its complete biodegradation. In this work, glucose was used as extra carbon source. Cyanuric hydrolase is the first enzyme in cyanuric acid (CA) catabolism, and is produced by a wide number of microorganisms. (Author)

  12. Solid-state Fermentation of Xylanase from Penicillium canescens 10-10c in a Multi-layer-packed Bed Reactor

    Science.gov (United States)

    Assamoi, Antoine A.; Destain, Jacqueline; Delvigne, Frank; Lognay, Georges; Thonart, Philippe

    Xylanase is produced by Penicillium canescens 10-10c from soya oil cake in static conditions using solid-state fermentation. The impact of several parameters such as the nature and the size of inoculum, bed-loading, and aeration is evaluated during the fermentation process. Mycelial inoculum gives more production than conidial inoculum. Increasing the quantity of inoculum enhances slightly xylanase production. Forced aeration induces more sporulation of strain and reduces xylanase production. However, forced moistened air improves the production compared to production obtained with forced dry air. In addition, increasing bed-loading reduces the specific xylanase production likely due to the incapacity of the Penicillium strain to grow deeply in the fermented soya oil cake mass. Thus, the best cultivation conditions involve mycelial inoculum form, a bed loading of 1-cm height and passive aeration. The maximum xylanase activity is obtained after 7 days of fermentation and attains 10,200 U/g of soya oil cake. These levels are higher than those presented in the literature and, therefore, show all the potentialities of this stock and this technique for the production of xylanase.

  13. Immobilisation of laccase on Eupergit supports and its application for the removal of endocrine disrupting chemicals in a packed-bed reactor

    NARCIS (Netherlands)

    Lloret, L.; Hollmann, F.; Eibes, G.; Feijoo, G.; Moreira, M.T.; Lema, J.M.

    2011-01-01

    Laccase from Myceliophthora thermophila was covalently immobilised on Eupergit C and Eupergit C 250L yielding specific activities of up to 17 and 80 U/g, respectively. Due to its superior activity, Eupergit C 250L was chosen for further research. The somewhat lower catalytic efficiency (based on the

  14. MODELLING AND CONTROL OF CONTINUOUS STIRRED TANK REACTOR WITH PID CONTROLLER

    Directory of Open Access Journals (Sweden)

    Artur Wodołażski

    2016-09-01

    Full Text Available This paper presents a model of dynamics control for continuous stirred tank reactor (CSTR in methanol synthesis in a three-phase system. The reactor simulation was carried out for steady and transient state. Efficiency ratio to achieve maximum performance of the product per reactor unit volume was calculated. Reactor dynamics simulation in closed loop allowed to received data for tuning PID controller (proportional-integral-derivative. The results of the regulation process allow to receive data for optimum reactor production capacity, along with local hot spots eliminations or temperature runaway.

  15. Accounting for porous structure in effective thermal conductivity calculations in a pebble bed reactor

    International Nuclear Information System (INIS)

    Antwerpen, W. van; Rousseau, P.G.; Toit, C.G. du

    2009-01-01

    A proper understanding of the mechanisms of heat transfer, flow and pressure drop through a packed bed of spheres is of utmost importance in the design of a high temperature pebble bed reactor. A thorough knowledge of the porous structure within the packed bed is important to any rigorous analysis of the transport phenomena, as all the heat and flow mechanisms are influenced by the porous structure. In this paper a new approach is proposed to simulate the effective thermal conductivity employing a combination of new and existing correlations for randomly packed beds. More attention is given to packing structure based on coordination number and contact angles, resulting in a more rigorous differentiation between the bulk and near-wall regions. The model accounts for solid conduction, gas conduction, contact area, surface roughness as well as radiation. (author)

  16. The operation characteristics of biohydrogen production in continuous stirred tank reactor with molasses

    Energy Technology Data Exchange (ETDEWEB)

    Hong, C.; Wei, H.; Jie-xuan, D.; Xin, Y.; Chuan-ping, Y. [Northeast Forestry Univ., Harbin (China). School of Forestry; Li, Y.F. [Northeast Forestry Univ., Harbin (China). School of Forestry; Shanghai Univ. Engineering, Shanghai (China). College of Chemistry and Chemical Engineering

    2010-07-01

    The anaerobic fermentation biohydrogen production in a continuous stirred tank reactor (CSTR) was investigated as a means for treating molasses wastewater. The research demonstrated that the reactor has the capacity of continuously producing hydrogen in an initial biomass (as volatile suspension solids) of 17.74 g/L, temperature of approximately 35 degrees Celsius, hydraulic retention time of 6 hours. The reactor could begin the ethanol-type fermentation in 12 days and realize stable hydrogen production. The study also showed that the CSTR reactor has a favourable stability even with an organic shock loading. The hydrogen yield and chemical oxygen demand (COD) increased, as did the hydrogen content.

  17. Evaluation of tritium production rate in a gas-cooled reactor with continuous tritium recovery system for fusion reactors

    Energy Technology Data Exchange (ETDEWEB)

    Matsuura, Hideaki, E-mail: mat@nucl.kyushu-u.ac.jp [Department of Applied Quantum Physics and Nuclear Engineering, Kyushu University, 744 Motooka, Fukuoka 819-0395 (Japan); Nakaya, Hiroyuki; Nakao, Yasuyuki [Department of Applied Quantum Physics and Nuclear Engineering, Kyushu University, 744 Motooka, Fukuoka 819-0395 (Japan); Shimakawa, Satoshi; Goto, Minoru; Nakagawa, Shigeaki [Japan Atomic Energy Agency, 4002 Oarai, Ibaraki 311-1393 (Japan); Nishikawa, Masabumi [Graduate School of Engineering Science, Kyushu University, 6-10-1 Hakozaki, Fukuoka 812-8581 (Japan)

    2013-10-15

    Highlights: • The performance of a gas-cooled reactor as a tritium production system was studied. • A continuous tritium recovery using helium gas was considered. • Gas-cooled reactors with 3 GW output in all can produce ∼6 kg of tritium in a year • Performance of the system was examined for Li{sub 4}SiO{sub 4}, Li{sub 2}TiO{sub 3} and LiAlO{sub 2} compounds. -- Abstract: The performance of a high-temperature gas-cooled reactor as a tritium production with continuous tritium recovery system is examined. A gas turbine high-temperature reactor of 300-MWe (600 MW) nominal capacity (GTHTR300) is assumed as the calculation target, and using the continuous-energy Monte Carlo transport code MVP-BURN, burn-up simulations for the three-dimensional entire-core region of the GTHTR300 were performed. A Li loading pattern for the continuous tritium recovery system in the gas-cooled reactor is presented. It is shown that module gas-cooled reactors with a total thermal output power of 3 GW in all can produce ∼6 kg of tritium maximum in a year.

  18. TiO2 Solar Photocatalytic Reactor Systems: Selection of Reactor Design for Scale-up and Commercialization—Analytical Review

    Directory of Open Access Journals (Sweden)

    Yasmine Abdel-Maksoud

    2016-09-01

    Full Text Available For the last four decades, viability of photocatalytic degradation of organic compounds in water streams has been demonstrated. Different configurations for solar TiO2 photocatalytic reactors have been used, however pilot and demonstration plants are still countable. Degradation efficiency reported as a function of treatment time does not answer the question: which of these reactor configurations is the most suitable for photocatalytic process and optimum for scale-up and commercialization? Degradation efficiency expressed as a function of the reactor throughput and ease of catalyst removal from treated effluent are used for comparing performance of different reactor configurations to select the optimum for scale-up. Comparison included parabolic trough, flat plate, double skin sheet, shallow ponds, shallow tanks, thin-film fixed-bed, thin film cascade, step, compound parabolic concentrators, fountain, slurry bubble column, pebble bed and packed bed reactors. Degradation efficiency as a function of system throughput is a powerful indicator for comparing the performance of photocatalytic reactors of different types and geometries, at different development scales. Shallow ponds, shallow tanks and fountain reactors have the potential of meeting all the process requirements and a relatively high throughput are suitable for developing into continuous industrial-scale treatment units given that an efficient immobilized or supported photocatalyst is used.

  19. Preliminary study on aerobic granular biomass formation with aerobic continuous flow reactor

    Science.gov (United States)

    Yulianto, Andik; Soewondo, Prayatni; Handajani, Marissa; Ariesyady, Herto Dwi

    2017-03-01

    A paradigm shift in waste processing is done to obtain additional benefits from treated wastewater. By using the appropriate processing, wastewater can be turned into a resource. The use of aerobic granular biomass (AGB) can be used for such purposes, particularly for the processing of nutrients in wastewater. During this time, the use of AGB for processing nutrients more reactors based on a Sequencing Batch Reactor (SBR). Studies on the use of SBR Reactor for AGB demonstrate satisfactory performance in both formation and use. SBR reactor with AGB also has been applied on a full scale. However, the use use of SBR reactor still posses some problems, such as the need for additional buffer tank and the change of operation mode from conventional activated sludge to SBR. This gives room for further reactor research with the use of a different type, one of which is a continuous reactor. The purpose of this study is to compare AGB formation using continuous reactor and SBR with same operation parameter. Operation parameter are Organic Loading Rate (OLR) set to 2,5 Kg COD/m3.day with acetate as substrate, aeration rate 3 L/min, and microorganism from Hospital WWTP as microbial source. SBR use two column reactor with volumes 2 m3, and continuous reactor uses continuous airlift reactor, with two compartments and working volume of 5 L. Results from preliminary research shows that although the optimum results are not yet obtained, AGB can be formed on the continuous reactor. When compared with AGB generated by SBR, then the characteristics of granular diameter showed similarities, while the sedimentation rate and Sludge Volume Index (SVI) characteristics showed lower yields.

  20. Bio-hydrogen production from molasses by anaerobic fermentation in continuous stirred tank reactor

    Science.gov (United States)

    Han, Wei; Li, Yong-feng; Chen, Hong; Deng, Jie-xuan; Yang, Chuan-ping

    2010-11-01

    A study of bio-hydrogen production was performed in a continuous flow anaerobic fermentation reactor (with an available volume of 5.4 L). The continuous stirred tank reactor (CSTR) for bio-hydrogen production was operated under the organic loading rates (OLR) of 8-32 kg COD/m3 reactor/d (COD: chemical oxygen demand) with molasses as the substrate. The maximum hydrogen production yield of 8.19 L/d was obtained in the reactor with the OLR increased from 8 kg COD/m3 reactor/d to 24 kg COD/m3 d. However, the hydrogen production and volatile fatty acids (VFAs) drastically decreased at an OLR of 32 kg COD/m3 reactor/d. Ethanoi, acetic, butyric and propionic were the main liquid fermentation products with the percentages of 31%, 24%, 20% and 18%, which formed the mixed-type fermentation.

  1. Air purification by catalytic oxidation in a reactor with periodic flow reversal

    NARCIS (Netherlands)

    van de Beld, L.; van de Beld, Bert; Westerterp, K.R.

    1994-01-01

    The behaviour of an adiabatic packed bed reactor with periodic flow reversal has been studied by means of model calculations. A heterogeneous model as well as a pseudo-homogeneous model have been developed. It is shown that a high degree of conversion can be obtained in an autothermal process even

  2. Biofilm reactors for ethanol production

    Energy Technology Data Exchange (ETDEWEB)

    Vega, J L; Clausen, E C; Gaddy, J L

    1988-07-01

    Whole cell immobilization has been studied in the laboratory during the last few years as a method to improve the performance and economics of most fermentation processes. Among the various techniques available for cell immobilization, methods that provide generation of a biofilm offer reduced diffusional resistance, high productivities, and simple operation. This paper reviews some of the important aspects of biofilm reactors for ethanol production, including reactor start-up, steady state behavior, process stability, and mathematical modeling. Special emphasis is placed on covalently bonded Saccharomyces cerevisiae in packed bed reactors.

  3. Simulation of emulsion copolymerization reactions in a continuous pulsed sieve-plate column reactor

    OpenAIRE

    C. Sayer; R. Giudici

    2004-01-01

    This work addressed the viability of using a pulsed sieve-plate column reactor to carry out continuous vinyl acetate/butyl acrylate emulsion copolymerization reactions. A rigorous mathematical model of emulsion copolymerization reactions in a tubular reactor with axial dispersion was used for this purpose. Operational conditions were defined to attain high monomer conversions at the reactor outlet in a relatively short residence time and, at the same time, produce a copolymer with a more homo...

  4. Simulation of emulsion copolymerization reactions in a continuous pulsed sieve-plate column reactor

    Directory of Open Access Journals (Sweden)

    Sayer C.

    2004-01-01

    Full Text Available This work addressed the viability of using a pulsed sieve-plate column reactor to carry out continuous vinyl acetate/butyl acrylate emulsion copolymerization reactions. A rigorous mathematical model of emulsion copolymerization reactions in a tubular reactor with axial dispersion was used for this purpose. Operational conditions were defined to attain high monomer conversions at the reactor outlet in a relatively short residence time and, at the same time, produce a copolymer with a more homogeneous composition.

  5. Parametric Sensitivity Study on Continuous Reactors with Stirring

    Directory of Open Access Journals (Sweden)

    Dr. Carlos Hernández-Pedrera

    2015-11-01

    Full Text Available In this work present the results obtained in a study of sensibility, by using a mathematical model developed for the simulation of the conduct of an endless reactor with agitation, by using as data source of information of reasonable operation of the industrial plant. The study permits value the effect that the changes in the variables of operation can occasion in the results of the process and the possibility that exists or not interactions between the variables analyzed.

  6. Autotrophic Nitrogen Removal in a Membrane-Aerated Biofilm Reactor Under Continuous Aeration: A Demonstration

    DEFF Research Database (Denmark)

    Gilmore, Kevin R.; Terada, Akihiko; Smets, Barth F.

    2013-01-01

    This work describes the successful coupling of partial nitrification (nitritation) and anaerobic ammonium oxidation in a membrane-aerated biofilm reactor (MABR) with continuous aeration. Controlling the relative surface loadings of oxygen versus ammonium prevented complete nitrite oxidation and a...

  7. Production of specific-structured lipids by enzymatic interesterification in a pilot continuous enzyme bed reactor

    DEFF Research Database (Denmark)

    Xu, Xuebing; Balchen, Steen; Høy, Carl-Erik

    1998-01-01

    Production of specific-structured lipids (interesterified lipids with a specific structure) by enzymatic interesterification was carried out in a continuous enzyme bed pilot scale reactor. Commercial immobilized lipase (Lipozyme IM) was used and investigations of acyl migration, pressure drop...

  8. Electroremediation of air pollution control residues in a continuous reactor

    DEFF Research Database (Denmark)

    Jensen, Pernille Erland; Ferreira, Célia M. D.; Hansen, Henrik K.

    2010-01-01

    Air pollution control (APC) residue from municipal solid waste incineration is considered hazardous waste due to its alkalinity and high content of salts and mobile heavy metals. Various solutions for the handling of APC-residue exist, however most commercial solutions involve landfilling. A demand...... were made with raw residue, water-washed residue, acid washed residue and acid-treated residue with emphasis on reduction of heavy metal mobility. Main results indicate that the reactor successfully removes toxic elements lead, copper, cadmium and zinc from the feed stream, suggesting...

  9. 1 kWe sodium borohydride hydrogen generation system Part II: Reactor modeling

    OpenAIRE

    Zhang, Jinsong; Zheng, Yuan; Gore, Jay P; Mudawar, Issam; Fisher, Timothy

    2007-01-01

    Sodium borohydride (NaBH4) hydrogen storage systems offer many advantages for hydrogen storage applications. The physical processes inside a NaBH4 packed bed reactor involve multi-component and multi-phase flow and multi-mode heat and mass transfer. These processes are also coupled with reaction kinetics. To guide reactor design and optimization, a reactor model involving all of these processes is desired. A onedimensional numerical model in conjunction with the assumption of homogeneous cata...

  10. Batch- and Continuous-Flow Aerobic Oxidation of 14-Hydroxy Opioids to 1,3-Oxazolidines-A Concise Synthesis of Noroxymorphone.

    Science.gov (United States)

    Gutmann, Bernhard; Weigl, Ulrich; Cox, D Phillip; Kappe, C Oliver

    2016-07-18

    14-Hydroxymorphinone is converted to noroxymorphone, the immediate precursor of important opioid antagonists, such as naltrexone and naloxone, in a three-step reaction sequence. The initial oxidation of the N-methyl group in 14-hydroxymorphinone with in situ generated colloidal palladium(0) as the catalyst and molecular oxygen as the terminal oxidant constitutes the key transformation in this new route. This oxidation results in the formation of an unexpected oxazolidine ring structure. Subsequent hydrolysis of the oxazolidine under reduced pressure followed by hydrogenation in a packed-bed flow reactor using palladium(0) as the catalyst provides noroxymorphone in high purity and good overall yield. To overcome challenges associated with gas-liquid reactions with molecular oxygen, the key oxidation reaction was translated to a continuous-flow process. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Continuous ethanol production using immobilized yeast cells entrapped in loofa-reinforced alginate carriers

    Directory of Open Access Journals (Sweden)

    Phoowit Bangrak

    2011-06-01

    Full Text Available A culture of Saccharomyces cerevisiae M30 entrapped in loofa-reinforced alginate was used for continuous ethanol fermentation in a packed-bed reactor with initial sugar concentrations of 200-248 g/L. Maximum ethanol productivity of 11.5 g/(L·h was obtained at an ethanol concentration of 57.4 g/L, an initial sugar concentration of 220 g/L and a dilution rate (D of 0.2 h-1. However, a maximum ethanol concentration of 82.1 g/L (productivity of 9.0 g/(L·h was obtained at a D of 0.11 h-1. Ethanol productivity in the continuous culture was 6-8-fold higher than that in the batch culture. Due to the developed carrier's high biocompatibility, high porosity, and good mechanical strength, advantages such as cell regeneration, reusability, altered mechanical strength, and high capacity to trap active cells in the reactor were achieved in this study. The immobilized cell reactor was successfully operated for 30 days without any loss in ethanol productivity. The average conversion yield was 0.43-0.45 throughout the entire operation, with an immobilization yield of 47.5%. The final total cell concentration in the reactor was 37.3 g/L (17.7 g/L immobilized cells and 19.6 g/L suspended cells. The concentration of suspended cells in the effluent was 0.8 g/L.

  12. Design and operation of a filter reactor for continuous production of a selected pharmaceutical intermediate

    DEFF Research Database (Denmark)

    Christensen, Kim Müller; Pedersen, Michael Jønch; Dam-Johansen, Kim

    2012-01-01

    in tetrahydrofuran solvent. The use of the filter reactor design was explored by examining the transferability of a synthesis step in a present full-scale semi-batch pharmaceutical production into continuous processing. The main advantages of the new continuous minireactor system, compared to the conventional semi...

  13. Computational Fluid Dynamics simulation of hydrothermal liquefaction of microalgae in a continuous plug-flow reactor.

    Science.gov (United States)

    Ranganathan, Panneerselvam; Savithri, Sivaraman

    2018-06-01

    Computational Fluid Dynamics (CFD) technique is used in this work to simulate the hydrothermal liquefaction of Nannochloropsis sp. microalgae in a lab-scale continuous plug-flow reactor to understand the fluid dynamics, heat transfer, and reaction kinetics in a HTL reactor under hydrothermal condition. The temperature profile in the reactor and the yield of HTL products from the present simulation are obtained and they are validated with the experimental data available in the literature. Furthermore, the parametric study is carried out to study the effect of slurry flow rate, reactor temperature, and external heat transfer coefficient on the yield of products. Though the model predictions are satisfactory in comparison with the experimental results, it still needs to be improved for better prediction of the product yields. This improved model will be considered as a baseline for design and scale-up of large-scale HTL reactor. Copyright © 2018 Elsevier Ltd. All rights reserved.

  14. PRELIMINARY DESIGN OF OSCILLATORY FLOW BIODIESEL REACTOR FOR CONTINUOUS BIODIESEL PRODUCTION FROM JATROPHA TRIGLYCERIDES

    Directory of Open Access Journals (Sweden)

    AZHARI T. I. MOHD. GHAZI

    2008-08-01

    Full Text Available The concept of a continuous process in producing biodiesel from jatropha oil by using an Oscillatory Flow Biodiesel Reactor (OFBR is discussed in this paper. It has been recognized that the batch stirred reactor is a primary mode used in the synthesis of biodiesel. However, pulsatile flow has been extensively researcehed and the fundamental principles have been successfully developed upon which its hydrodynamics are based. Oscillatory flow biodiesel reactor offers precise control of mixing by means of the baffle geometry and pulsation which facilitates to continuous operation, giving plug flow residence time distribution with high turbulence and enhanced mass and heat transfer. In conjunction with the concept of reactor design, parameters such as reactor dimensions, the hydrodynamic studies and physical properties of reactants must be considered prior to the design work initiated recently. The OFBR reactor design involves the use of simulation software, ASPEN PLUS and the reactor design fundamentals. Following this, the design parameters shall be applied in fabricating the OFBR for laboratory scale biodiesel production.

  15. Renewable Wood Pulp Paper Reactor with Hierarchical Micro/Nanopores for Continuous-Flow Nanocatalysis.

    Science.gov (United States)

    Koga, Hirotaka; Namba, Naoko; Takahashi, Tsukasa; Nogi, Masaya; Nishina, Yuta

    2017-06-22

    Continuous-flow nanocatalysis based on metal nanoparticle catalyst-anchored flow reactors has recently provided an excellent platform for effective chemical manufacturing. However, there has been limited progress in porous structure design and recycling systems for metal nanoparticle-anchored flow reactors to create more efficient and sustainable catalytic processes. In this study, traditional paper is used for a highly efficient, recyclable, and even renewable flow reactor by tailoring the ultrastructures of wood pulp. The "paper reactor" offers hierarchically interconnected micro- and nanoscale pores, which can act as convective-flow and rapid-diffusion channels, respectively, for efficient access of reactants to metal nanoparticle catalysts. In continuous-flow, aqueous, room-temperature catalytic reduction of 4-nitrophenol to 4-aminophenol, a gold nanoparticle (AuNP)-anchored paper reactor with hierarchical micro/nanopores provided higher reaction efficiency than state-of-the-art AuNP-anchored flow reactors. Inspired by traditional paper materials, successful recycling and renewal of AuNP-anchored paper reactors were also demonstrated while high reaction efficiency was maintained. © 2017 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA.

  16. Experiment on continuous operation of the Brazilian IEA-R1 research reactor

    International Nuclear Information System (INIS)

    Freitas Pintaud, M. de

    1994-01-01

    In order to increase the radioisotope production in the IEA-R1 research reactor at IPEN/CNEN-SP, it has been proposed a change in its operation regime from 8 hours per day and 5 days per week to continuous 48 hours per week. The necessary reactor parameters for this new operation regime were obtained through an experiment in which the reactor was for the first time operated in the new regime. This work presents the principal results from this experiment: xenon reactivity, new shutdown margins, and reactivity loss due to fuel burnup in the new operation regime. (author)

  17. Kinetic model for torrefaction of wood chips in a pilot-scale continuous reactor

    DEFF Research Database (Denmark)

    Shang, Lei; Ahrenfeldt, Jesper; Holm, Jens Kai

    2014-01-01

    accordance with the model data. In an additional step a continuous, pilot scale reactor was built to produce torrefied wood chips in large quantities. The "two-step reaction in series" model was applied to predict the mass yield of the torrefaction reaction. Parameters used for the calculation were...... at different torrefaction temperatures, it was possible to predict the HHV of torrefied wood chips from the pilot reactor. The results from this study and the presented modeling approach can be used to predict the product quality from pilot scale torrefaction reactors based on small scale experiments and could...

  18. Mathematical modeling of methyl ester concentration distribution in a continuous membrane tubular reactor and comparison with conventional tubular reactor

    Science.gov (United States)

    Talaghat, M. R.; Jokar, S. M.; Modarres, E.

    2017-10-01

    The reduction of fossil fuel resources and environmental issues made researchers find alternative fuels include biodiesels. One of the most widely used methods for production of biodiesel on a commercial scale is transesterification method. In this work, the biodiesel production by a transesterification method was modeled. Sodium hydroxide was considered as a catalyst to produce biodiesel from canola oil and methanol in a continuous tubular ceramic membranes reactor. As the Biodiesel production reaction from triglycerides is an equilibrium reaction, the reaction rate constants depend on temperature and related linearly to catalyst concentration. By using the mass balance for a membrane tubular reactor and considering the variation of raw materials and products concentration with time, the set of governing equations were solved by numerical methods. The results clearly show the superiority of membrane reactor than conventional tubular reactors. Afterward, the influences of molar ratio of alcohol to oil, weight percentage of the catalyst, and residence time on the performance of biodiesel production reactor were investigated.

  19. Thermal-hydraulic modeling of porous bed reactors

    International Nuclear Information System (INIS)

    Araj, K.J.; Nourbakhsh, H.P.

    1987-01-01

    Optimum design of nuclear reactor core requires an iterative approach between the thermal-hydraulic, neutronic and operational analysis. This paper concentrates on the thermal-hydraulic behavior of a hydrogen cooled, small particle bed reactor (PBR). The PBR core, modeled here, consists of a hexagonal array of fuel elements embedded in a moderator matrix. The fuel elements are annular packed beds of fuel particles held between two porous cylindrical frits. These particles, 500 to 600 μm in diameter, have a uranium carbide core, which is coated by two layers of graphite and an outer coating of zirconium carbide. Coolant flow, radially inward, from the cold frit through the packed bed and hot frit and axially out the channel, formed by the hot frit, to a common plenum. 5 refs., 1 fig., 2 tabs

  20. CFD optimization of continuous stirred-tank (CSTR) reactor for biohydrogen production.

    Science.gov (United States)

    Ding, Jie; Wang, Xu; Zhou, Xue-Fei; Ren, Nan-Qi; Guo, Wan-Qian

    2010-09-01

    There has been little work on the optimal configuration of biohydrogen production reactors. This paper describes three-dimensional computational fluid dynamics (CFD) simulations of gas-liquid flow in a laboratory-scale continuous stirred-tank reactor used for biohydrogen production. To evaluate the role of hydrodynamics in reactor design and optimize the reactor configuration, an optimized impeller design has been constructed and validated with CFD simulations of the normal and optimized impeller over a range of speeds and the numerical results were also validated by examination of residence time distribution. By integrating the CFD simulation with an ethanol-type fermentation process experiment, it was shown that impellers with different type and speed generated different flow patterns, and hence offered different efficiencies for biohydrogen production. The hydrodynamic behavior of the optimized impeller at speeds between 50 and 70 rev/min is most suited for economical biohydrogen production. Copyright 2010 Elsevier Ltd. All rights reserved.

  1. Transfer of reaction-technical findings from pilot-scale nitrogen elimination to technical-scale organic packed beds; Uebertragung von reaktionstechnischen Erkenntnissen an Pilotanlagen zur Stickstoffentfernung auf grosstechnische Biofestbettanlagen

    Energy Technology Data Exchange (ETDEWEB)

    Ante, A.; Brambach, R. [Lurgi Bamag GmbH, Butzbach (Germany)

    1999-07-01

    Organic packed beds offer some process engineering advantages: first of all an enormously high turnover rate per unit of space, low temperature dependence and, because of the flow pipe characteristics, the possibility to achieve very low effluent concentrations. In addition, the filtration effect binds solids, hence the concentration of solids in the effluent is very low. The formation of biofilm enhances this filter effect. Decisive kinetic parameters for nitrification systems are the rated temperature, the ratio of COD to N, and peak loads. For denitrification the design parameters are, beside temperature, loading with solids, the specific surface of the carrier material and filtration speed. In extensive investigations process variants were studied. They enhance the rate of turnover of nitrification with the aid of auxiliaries or through oxygen enrichment of process air to such an extent as to permit aimed buffering of peak ammonium freights. This constitutes a process-technical solution to one of the gravest drawbacks of packed-bed technology. (orig.) [German] Biofestbettanlagen bieten einige verfahrenstechnische Vorteile, in erster Linie eine enorm hohe Raumumsatzleistung, eine geringere Temperaturabhaengigkeit und aufgrund der Stroemungsrohrcharakteristik die Moeglichkeit sehr geringe Ablaufkonzentrationen zu erreichen. Zudem ist mit der Filtration aufgrund der Filterwirkung eine sehr geringe Feststoffkonzentration im Ablauf verbunden. Diese Filterwirkung wird durch die Ausbildung des Biofilmes noch untestuetzt. Die entscheidenden kinetischen Auslegungsgroessen fuer die Nitrifikation sind die Auslegungstemperatur, das CSB:N-Verhaeltnis sowie die Spitzenbelastungen. Fuer die Denitrifikation stellen neben der Temperatur, die Feststoffbeladung, die spezifische Oberflaeche des Traegermaterials sowie die Filtergeschwindigkeit die Auslegungsparameter dar. Durch umfangreiche Untersuchungen wurden Verfahrensvarianten erforscht, welche durch den Einsatz von

  2. Characterization of a continuous agitated cell reactor for oxygen dependent biocatalysis

    DEFF Research Database (Denmark)

    Pedersen, Asbjørn Toftgaard; Teresa de Melo Machado Simoes Carvalho, Ana; Sutherland, Euan

    2017-01-01

    Biocatalytic oxidation reactions employing molecular oxygen as the electron acceptor are difficult to conduct in a continuous flow reactor because of the requirement for high oxygen transfer rates. In this paper, the oxidation of glucose to glucono-1,5-lactone by glucose oxidase was used as a model...

  3. Beyond organometallic flow chemistry : the principles behind the use of continuous-flow reactors for synthesis

    NARCIS (Netherlands)

    Noel, T.; Su, Y.; Hessel, V.; Noël, T.

    2015-01-01

    Flow chemistry is typically used to enable challenging reactions which are difficult to carry out in conventional batch equipment. Consequently, the use of continuous-flow reactors for applications in organometallic and organic chemistry has witnessed a spectacular increase in interest from the

  4. Reactor operating procedures for start up of continuously operated chemical plants

    NARCIS (Netherlands)

    Verwijs, J.W.; Verwijs, J.W.; Kösters, P.H.; van den Berg, Henderikus; Westerterp, K.R.; Kosters, P.G.H.

    1995-01-01

    Rules are presented for the startup of an adiabatic tubular reactor, based on a qualitative analysis of the dynamic behavior of continuously-operated vapor- and liquid-phase processes. The relationships between the process dynamics, operating criteria, and operating constraints are investigated,

  5. Continuous ARGET ATPR of methyl methacrylate and butyl acrylate in a stirred tank reactor

    NARCIS (Netherlands)

    Chan, N.; Meuldijk, J.; Cunningham, M.F.; Hutchinson, R.A.

    2013-01-01

    ARGET ATRP (activator regenerated by electron transfer atom transfer radical polymerization) of butyl acrylate (BA) and methyl methacrylate (MMA) was successfully adapted from a batch process to a continuous stirred tank reactor (CSTR) with 50 ppm copper. A series of batch polymerizations were first

  6. Heat transfer and the continuous production of hydroxypropyl starch in a static mixer reactor

    NARCIS (Netherlands)

    Lammers, Gerard; Beenackers, Antonie A. C. M.

    1994-01-01

    A novel continuous reactor for the chemical derivation of aqueous starch solutions based on static mixers is proposed. Both the experimentally observed axial and radial temperature gradients in the static mixer could be accurately described by a pseudohomogeneous two-dimensional heat transfer (PTHT)

  7. Kinetic parameters of hydroprocessing reactions in a flow reactor

    Energy Technology Data Exchange (ETDEWEB)

    Raychaudhuri, U.; Banerjee, T.S.; Ghar, R.N. (Indian Institute of Technology, Kharagpur (India))

    1994-01-01

    The change in distillation properties of a blend of light and heavy distillates over a commercial hydrotreating catalyst was studied using a small packed bed reactor. The results were interpreted assuming a pseudo-component model that took into account the physical and chemical complexity of the system. A first order series-parallel reaction mechanism was found to be valid for the operating conditions involved. Pore diffusion effects were also taken into consideration. 8 refs., 7 figs., 1 tab.

  8. Simulation of Reforming Reactor Tube: Quantifying Catalyst Pellet's Effectiveness Factor

    OpenAIRE

    Da Cruz, Flavio Eduardo

    2016-01-01

    In this work, a consistent mathematical model to simulate a spherical catalytic pellet and a Packed-Bed Reactor (PBR) is develop. The Dusty Gas Model (DGM) is applied to the calculation of the diffusive fluxes in the porous media. Simulations are executed considering hydrogen production from steam methane reforming. Species’ diffusivities are calculated using data from literature as well as the values for tortuosity and porosity. The pellet simulation is performed considering mass, species, m...

  9. Dry fermentation of manure with straw in continuous plug flow reactor: Reactor development and process stability at different loading rates.

    Science.gov (United States)

    Patinvoh, Regina J; Kalantar Mehrjerdi, Adib; Sárvári Horváth, Ilona; Taherzadeh, Mohammad J

    2017-01-01

    In this work, a plug flow reactor was developed for continuous dry digestion processes and its efficiency was investigated using untreated manure bedded with straw at 22% total solids content. This newly developed reactor worked successfully for 230days at increasing organic loading rates of 2.8, 4.2 and 6gVS/L/d and retention times of 60, 40 and 28days, respectively. Organic loading rates up to 4.2gVS/L/d gave a better process stability, with methane yields up to 0.163LCH 4 /gVS added /d which is 56% of the theoretical yield. Further increase of organic loading rate to 6gVS/L/d caused process instability with lower volatile solid removal efficiency and cellulose degradation. Copyright © 2016 Elsevier Ltd. All rights reserved.

  10. Microorganism selection and biosurfactant production in a continuously and periodically operated bioslurry reactor.

    Science.gov (United States)

    Cassidy, D P; Hudak, A J

    2001-06-29

    A continuous-flow reactor (CSTR) and a soil slurry-sequencing batch reactor (SS-SBR) were maintained in 8l vessels for 180 days to treat a soil contaminated with diesel fuel (DF). Concentrations of Candida tropicalis, Brevibacterium casei, Flavobacterium aquatile, Pseudomonas aeruginosa, and Pseudomonas fluorescens were determined using fatty acid methyl ester (FAME) analysis. DF removal (biological and volatile) and biosurfactant concentrations were measured. The SS-SBR encouraged the growth of biosurfactant-producing species relative to the CSTR. Counts of biosurfactant-producing species (C. tropicalis, P. aeruginosa, P. fluorescens) relative to total microbial counts were 88% in the SS-SBR and 23% in the CSTR. Biosurfactants were produced in the SS-SBR to levels of nearly 70 times the critical micelle concentration (CMC) early in the cycle, but were completely degraded by the end of each cycle. No biosurfactant production was observed in the CSTR. DF biodegradation rates were over 40% greater and DF stripping was over five times lower in the SS-SBR than the CSTR. However, considerable foaming occurred in the SS-SBR. Reversing the mode of operation in the reactors on day 80 caused a complete reversal in microbial consortia and reactor performance by day 120. These results show that bioslurry reactor operation can be manipulated to control overall reactor performance.

  11. [Research on change process of nitrosation granular sludge in continuous stirred-tank reactor].

    Science.gov (United States)

    Yin, Fang-Fang; Liu, Wen-Ru; Wang, Jian-Fang; Wu, Peng; Shen, Yao-Liang

    2014-11-01

    In order to investigate the effect of different types of reactors on the nitrosation granular sludge, a continuous stirred-tank reactor (CSTR) was studied, using mature nitrosation granular sludge cultivated in sequencing batch reactor (SBR) as seed sludge. Results indicated that the change of reactor type and influent mode could induce part of granules to lose stability with gradual decrease in sludge settling ability during the initial period of operation. However, the flocs in CSTR achieved fast granulation in the following reactor operation. In spite of the changes of particle size distribution, e. g. the decreasing number of granules with diameter larger than 2.5 mm and the increasing number of granules with diameter smaller than 0.3 mm, granular sludge held the absolute predominance of sludge morphology in CSTR during the entire experimental period. Moreover, results showed that the change of reactor type and influent mode didn't affect the nitrite accumulation rate which was still kept at about 85% in effluent. Additionally, the average activity of the sludge in CSTR was stronger than that of the seed sludge, because the newly generated small particles in CSTR had higher specific reactive activity than the larger granules.

  12. Removal of natural organic matter and arsenic from water by electrocoagulation/flotation continuous flow reactor

    International Nuclear Information System (INIS)

    Mohora, Emilijan; Rončević, Srdjan; Dalmacija, Božo; Agbaba, Jasmina; Watson, Malcolm; Karlović, Elvira; Dalmacija, Milena

    2012-01-01

    Highlights: ► A continuous electrocoagulation/flotation reactor was designed built and operated. ► Highest NOM removal according to UV 254 was 77% relative to raw groundwater. ► Highest NOM removal accordance to DOC was 71%, relative to raw groundwater. ► Highest As removal archived was 85% (6.2 μg/l), relative to raw groundwater. ► Specific reactor energy and electrode consumption was 1.7 kWh/m 3 and 66 g Al/m 3 . - Abstract: The performance of the laboratory scale electrocoagulation/flotation (ECF) reactor in removing high concentrations of natural organic matter (NOM) and arsenic from groundwater was analyzed in this study. An ECF reactor with bipolar plate aluminum electrodes was operated in the horizontal continuous flow mode. Electrochemical and flow variables were optimized to examine ECF reactor contaminants removal efficiency. The optimum conditions for the process were identified as groundwater initial pH 5, flow rate = 4.3 l/h, inter electrode distance = 2.8 cm, current density = 5.78 mA/cm 2 , A/V ratio = 0.248 cm −1 . The NOM removal according to UV 254 absorbance and dissolved organic matter (DOC) reached highest values of 77% and 71% respectively, relative to the raw groundwater. Arsenic removal was 85% (6.2 μg As/l) relative to raw groundwater, satisfying the drinking water standards. The specific reactor electrical energy consumption was 17.5 kWh/kg Al. The specific aluminum electrode consumption was 66 g Al/m 3 . According to the obtained results, ECF in horizontal continuous flow mode is an energy efficient process to remove NOM and arsenic from groundwater.

  13. Removal of natural organic matter and arsenic from water by electrocoagulation/flotation continuous flow reactor

    Energy Technology Data Exchange (ETDEWEB)

    Mohora, Emilijan, E-mail: emohora@ifc.org [University of Novi Sad Faculty of Sciences, Department of Chemistry, Biochemistry and Environmental Protection, Trg D. Obradovica 3, 21000 Novi Sad (Serbia); Roncevic, Srdjan; Dalmacija, Bozo; Agbaba, Jasmina; Watson, Malcolm; Karlovic, Elvira; Dalmacija, Milena [University of Novi Sad Faculty of Sciences, Department of Chemistry, Biochemistry and Environmental Protection, Trg D. Obradovica 3, 21000 Novi Sad (Serbia)

    2012-10-15

    Highlights: Black-Right-Pointing-Pointer A continuous electrocoagulation/flotation reactor was designed built and operated. Black-Right-Pointing-Pointer Highest NOM removal according to UV{sub 254} was 77% relative to raw groundwater. Black-Right-Pointing-Pointer Highest NOM removal accordance to DOC was 71%, relative to raw groundwater. Black-Right-Pointing-Pointer Highest As removal archived was 85% (6.2 {mu}g/l), relative to raw groundwater. Black-Right-Pointing-Pointer Specific reactor energy and electrode consumption was 1.7 kWh/m{sup 3} and 66 g Al/m{sup 3}. - Abstract: The performance of the laboratory scale electrocoagulation/flotation (ECF) reactor in removing high concentrations of natural organic matter (NOM) and arsenic from groundwater was analyzed in this study. An ECF reactor with bipolar plate aluminum electrodes was operated in the horizontal continuous flow mode. Electrochemical and flow variables were optimized to examine ECF reactor contaminants removal efficiency. The optimum conditions for the process were identified as groundwater initial pH 5, flow rate = 4.3 l/h, inter electrode distance = 2.8 cm, current density = 5.78 mA/cm{sup 2}, A/V ratio = 0.248 cm{sup -1}. The NOM removal according to UV{sub 254} absorbance and dissolved organic matter (DOC) reached highest values of 77% and 71% respectively, relative to the raw groundwater. Arsenic removal was 85% (6.2 {mu}g As/l) relative to raw groundwater, satisfying the drinking water standards. The specific reactor electrical energy consumption was 17.5 kWh/kg Al. The specific aluminum electrode consumption was 66 g Al/m{sup 3}. According to the obtained results, ECF in horizontal continuous flow mode is an energy efficient process to remove NOM and arsenic from groundwater.

  14. A continuing success - The United States Foreign Research Reactor Spent Nuclear Fuel Acceptance Program

    International Nuclear Information System (INIS)

    Mustin, Tracy P.; Clapper, Maureen; Reilly, Jill E.

    2000-01-01

    The United States Department of Energy, in consultation with the Department of State, adopted the Nuclear Weapons Nonproliferation Policy Concerning Foreign Research Reactor Spent Nuclear Fuel in May 1996. To date, the Foreign Research Reactor (FRR) Spent Nuclear Fuel (SNF) Acceptance Program, established under this policy, has completed 16 spent fuel shipments. 2,651 material test reactor (MTR) assemblies, one Slowpoke core containing less than 1 kilogram of U.S.-origin enriched uranium, 824 Training, Research, Isotope, General Atomic (TRIGA) rods, and 267 TRIGA pins from research reactors around the world have been shipped to the United States so far under this program. As the FRR SNF Acceptance Program progresses into the fifth year of implementation, a second U.S. cross country shipment has been completed, as well as a second overland truck shipment from Canada. Both the cross country shipment and the Canadian shipment were safely and successfully completed, increasing our knowledge and experience in these types of shipments. In addition, two other shipments were completed since last year's RERTR meeting. Other program activities since the last meeting included: taking pre-emptive steps to avoid license amendment pitfalls/showstoppers for spent fuel casks, publication of a revision to the Record of Decision allowing up to 16 casks per ocean going vessel, and the issuance of a cable to 16 of the 41 eligible countries reminding their governments and the reactor operators that the U.S.-origin uranium in their research reactors may be eligible for return to the United States under the Acceptance Program and urging them to begin discussions on shipping schedules. The FRR SNF program has also supported the Department's implementation of the competitive pricing policy for uranium and resumption of shipments of fresh uranium for fabrication into assemblies for research reactors. The United States Foreign Research Reactor Spent Nuclear Fuel Acceptance Program continues

  15. Electro-Fenton decolourisation of dyes in an airlift continuous reactor using iron alginate beads.

    Science.gov (United States)

    Iglesias, O; Rosales, E; Pazos, M; Sanromán, M A

    2013-04-01

    In this study, electro-Fenton dye degradation was performed in an airlift continuous reactor configuration by harnessing the catalytic activity of Fe alginate gel beads. Electro-Fenton experiments were carried out in an airlift reactor with a working volume of 1.5 L, air flow of 1.5 L/min and 115 g of Fe alginate gel beads. An electric field was applied by two graphite bars connected to a direct current power supply with a constant potential drop. In this study, Lissamine Green B and Reactive Black 5 were selected as model dyes. Fe alginate gel beads can be used as an effective heterogeneous catalyst for the degradation of organic dyes in the electro-Fenton process, as they are more efficient than the conventional electrochemical techniques. At optimal working conditions (3 V and pH 2), the continuous process was performed. For both dyes, the degree of decolourisation increases when the residence time augments. Taking into account hydrodynamic and kinetic behaviour, a model to describe the reactor profile was obtained, and the standard deviation between experimental and theoretical data was lower than 6%. The results indicate the suitability of the electro-Fenton technique to oxidise polluted effluents in the presence of Fe alginate gel beads. Moreover, the operation is possible in a continuous airlift reactor, due to the entrapment of iron in the alginate matrix.

  16. Effect of organic loading rate on dark fermentative hydrogen production in the continuous stirred tank reactor and continuous mixed immobilized sludge reactor from waste pastry hydrolysate.

    Science.gov (United States)

    Han, Wei; Hu, Yunyi; Li, Shiyi; Nie, Qiulin; Zhao, Hongting; Tang, Junhong

    2016-12-01

    Waste pastry (6%, w/v) was hydrolyzed by the produced glucoamylase and protease to obtain the glucose (19.8g/L) and free amino nitrogen (179mg/L) solution. Then, the effect of organic loading rate (OLR) (8-40kgCOD/(m 3 d)) on dark fermentative hydrogen production in the continuous stirred tank reactor (CSTR) and continuous mixed immobilized sludge reactor (CMISR) from waste pastry hydrolysate was investigated and compared. The maximum hydrogen production rate of CSTR (277.76mL/(hL)) and CMISR (320.2mL/(hL)) were achieved at OLR of 24kgCOD/(m 3 d) and 32kgCOD/(m 3 d), respectively. Carbon recovery ranged from 75.2-84.1% in the CSTR and CMISR with the balance assumed to be converted to biomass. One gram waste pastry could produce 0.33g (1.83mmol) glucose which could be further converted to 79.24mL (3.54mmol) hydrogen in the CMISR or 91.66mL (4.09mmol) hydrogen in the CSTR. This is the first study which reports dark fermentative hydrogen production from waste pastry. Copyright © 2016 Elsevier Ltd. All rights reserved.

  17. Correlation between interstitial flow and pore structure in packed bed. 1st Report. Axial velocity measurement using MRI and visualization of axial channel flow; Juten sonai ryudo to kugeki kozo no sokan. 1. MRI ni yoru jikuhoko ryusoku bunpu no keisoku to jikiuhoko channel ryu no kashika

    Energy Technology Data Exchange (ETDEWEB)

    Ogawa, K; Yokouchi, Y; Hirai, S [Tokyo Institute of Technology, Tokyo (Japan)

    2000-02-25

    Structure and velocity measurements using magnetic resonance imaging (MRI) have been performed experimentally to obtain a correlation between pore structure and interstitial flow through the packed bed of 5 mm diameter in the tube of 36 mm ID. To measure axial velocity maps of water flow through the packed bed, the phase method of using the phase difference of water spin magnetization between flowing and stagnant fluids by applying magnetic fields with bipolar gradients was employed. The spatial resolution of the obtained map in 0.2 mm x 0.2 mm x 0.5 mm. It was made clear from the obtained axial velocity maps that channel flows with higher axial velocity were induced not only near the wall but also in the internal region of the packed bed. Furthermore, pore structure of the packed bed was characterized from multi-slice images by partitioning of void space and combining of each pore section along the axial direction to analyze the structure-flow correlation. It was found from image analysis that axial channels with long and straight void space existed in the pore structure, and that most of the channel flows with higher axial velocity were induced in the axial channels. The flow rate through an axial channel depends on the square of the averaged cross section of the axial channel. (author)

  18. Ethanol production in an immobilized-cell column reactor: The effects of micro-aeration and dual feeds

    Energy Technology Data Exchange (ETDEWEB)

    Lee, K

    1988-01-01

    Immobilized Saccharomyces cerevesiae cells adsorbed onto wood chips in a packed-bed bioreactor were used for ethanol fermentation from glucose solution. In aerobic and anaerobic batch experiments, an increase in initial glucose concentration resulted in a reduction of the specific growth rate, but no apparent glucose inhibition was found at initial glucose concentrations of ca <120 g/l. Since it is inevitable to use high substrate concentration to obtain high product concentration, experiments were performed in an immobilized-cell reactor (ICR) to examine any improvements achieved by a dual-feed mode over a continuous ICR system. The dual scheme can provide the same total amount of substrate while keeping the maximum substrate concentration to which the cells are exposed to about half of that in the single-feed case. In the dual-feed ICR, the ethanol production rate was 15% higher than that of the single-fed ICR. Experiments in skewed and vertical ICRs were performed to observe the difference in CO{sub 2} bubble removal; the bubbles were smoothly released in the skewed ICR compared to significant CO{sub 2} accumulation in the vertical ICR, and a biomass buildup on the wood surface was also observed. The experimental results indicate that trace amounts of dissolved oxygen stimulated fermentation rates, with one experiment showing a 31% improvement in ethanol productivity using aeration. At a controlled aeration rate, cells were observed to flocculate naturally onto the wood surface. Plugging of the void spaces, due to excess cell growth and intermittent CO{sub 2} holdup, was observed to begin at the base of the packed bed and progressed upward with time, thus undesirable channelling of liquid flow occurred. 200 refs., 76 figs., 21 tabs.

  19. Continuous Photo-Oxidation in a Vortex Reactor: Efficient Operations Using Air Drawn from the Laboratory.

    Science.gov (United States)

    Lee, Darren S; Amara, Zacharias; Clark, Charlotte A; Xu, Zeyuan; Kakimpa, Bruce; Morvan, Herve P; Pickering, Stephen J; Poliakoff, Martyn; George, Michael W

    2017-07-21

    We report the construction and use of a vortex reactor which uses a rapidly rotating cylinder to generate Taylor vortices for continuous flow thermal and photochemical reactions. The reactor is designed to operate under conditions required for vortex generation. The flow pattern of the vortices has been represented using computational fluid dynamics, and the presence of the vortices can be easily visualized by observing streams of bubbles within the reactor. This approach presents certain advantages for reactions with added gases. For reactions with oxygen, the reactor offers an alternative to traditional setups as it efficiently draws in air from the lab without the need specifically to pressurize with oxygen. The rapid mixing generated by the vortices enables rapid mass transfer between the gas and the liquid phases allowing for a high efficiency dissolution of gases. The reactor has been applied to several photochemical reactions involving singlet oxygen ( 1 O 2 ) including the photo-oxidations of α-terpinene and furfuryl alcohol and the photodeborylation of phenyl boronic acid. The rotation speed of the cylinder proved to be key for reaction efficiency, and in the operation we found that the uptake of air was highest at 4000 rpm. The reactor has also been successfully applied to the synthesis of artemisinin, a potent antimalarial compound; and this three-step synthesis involving a Schenk-ene reaction with 1 O 2 , Hock cleavage with H + , and an oxidative cyclization cascade with triplet oxygen ( 3 O 2 ), from dihydroartemisinic acid was carried out as a single process in the vortex reactor.

  20. Continuous backfitting measures for the FRG-1 and FRG-2 research reactors

    International Nuclear Information System (INIS)

    Blom, K.H.; Falck, K.; Krull, W.

    1990-01-01

    The GKSS-Research Centre Geesthacht GmbH has been operating the research reactors FRG-1 and FRG-2 with power levels of 5 MW and 15 MW for 31 and 26 years respectively. Safe operation at full power levels over so many years with an average utilization between 180 d to 250 d per year is possible only with great efforts in modernization and upgrading of the research reactors. Emphasis has been placed on backfitting since around 1975. At that time within the Federal Republic of Germany many new guidelines, rules, ordinances, and standards in the field of (power) reactor safety were published. Much work has been done on the modernization of the FRG-1 and FRG-2 research reactors therefore within the last ten years. Work done within the last two years and presently underway includes: measures against water leakage through the concrete and along the beam tubes; repair of both cooling towers; modernization of the ventilation system; measures for fire protection; activities in water chemistry and water quality; installation of a double tubing for parts of the primary piping of the FRG-1; replacement of instrumentation, process control systems (operation and monitoring system) and alarm system; renewal of the emergency power supply; installation of internal lightning protection; installation of a cold neutron source; enrichment reduction for FRG-1. These efforts will continue to allow safe operation of our research reactors over their whole operational life

  1. Continuous removal and recovery of tellurium in an upflow anaerobic granular sludge bed reactor

    Energy Technology Data Exchange (ETDEWEB)

    Mal, Joyabrata, E-mail: joyabrata2006@gmail.com [UNESCO-IHE, Westvest 7, 2611 AX Delft (Netherlands); Nancharaiah, Yarlagadda V. [Biofouling and Biofilm Processes Section, Water and Steam Chemistry Division, Bhabha Atomic Research Centre, Kalpakkam, 603102, Tamil Nadu (India); Homi Bhabha National Institute, Anushakti Nagar Complex, Mumbai 400094 (India); Maheshwari, Neeraj [CNRS UMR 7338, BMBI University de Technologie Compiegne, 60200 Compiegne (France); Hullebusch, Eric D. van [UNESCO-IHE, Westvest 7, 2611 AX Delft (Netherlands); Université Paris-Est, Laboratoire Géomatériaux et Environnement (LGE), EA 4508, UPEM, 77454, Marne-la-Vallée (France); Lens, Piet N.L. [UNESCO-IHE, Westvest 7, 2611 AX Delft (Netherlands); Department of Chemistry and Bioengineering, Tampere University of Technology, P.O-Box 541, Tampere (Finland)

    2017-04-05

    Highlights: • Tellurite bioreduction coupled to recovery of biogenic Te(0) nanocrystals. • First report on continuous tellurite removal in a UASB reactor. • Biogenic Te(0) was mainly associated with loosely-bound EPS of granular sludge. • Repeated exposure to tellurite caused compositional changes in the EPS matrix. - Abstract: Continuous removal of tellurite (TeO{sub 3}{sup 2−}) from synthetic wastewater and subsequent recovery in the form of elemental tellurium was studied in an upflow anaerobic granular sludge bed (UASB) reactor operated at 30 °C. The UASB reactor was inoculated with anaerobic granular sludge and fed with lactate as carbon source and electron donor at an organic loading rate of 0.6 g COD L{sup −1} d{sup −1}. After establishing efficient and stable COD removal, the reactor was fed with 10 mg TeO{sub 3}{sup 2−} L{sup −1} for 42 d before increasing the influent concentration to 20 mg TeO{sub 3}{sup 2−} L{sup −1}. Tellurite removal (98 and 92%, respectively, from 10 and 20 mg Te L{sup −1}) was primarily mediated through bioreduction and most of the removed Te was retained in the bioreactor. Characterization using XRD, Raman spectroscopy, SEM-EDX and TEM confirmed association of tellurium with the granular sludge, typically in the form of elemental Te(0) deposits. Furthermore, application of an extracellular polymeric substances (EPS) extraction method to the tellurite reducing sludge recovered up to 78% of the tellurium retained in the granular sludge. This study demonstrates for the first time the application of a UASB reactor for continuous tellurite removal from tellurite-containing wastewater coupled to elemental Te(0) recovery.

  2. Continuous removal and recovery of tellurium in an upflow anaerobic granular sludge bed reactor

    International Nuclear Information System (INIS)

    Mal, Joyabrata; Nancharaiah, Yarlagadda V.; Maheshwari, Neeraj; Hullebusch, Eric D. van; Lens, Piet N.L.

    2017-01-01

    Highlights: • Tellurite bioreduction coupled to recovery of biogenic Te(0) nanocrystals. • First report on continuous tellurite removal in a UASB reactor. • Biogenic Te(0) was mainly associated with loosely-bound EPS of granular sludge. • Repeated exposure to tellurite caused compositional changes in the EPS matrix. - Abstract: Continuous removal of tellurite (TeO 3 2− ) from synthetic wastewater and subsequent recovery in the form of elemental tellurium was studied in an upflow anaerobic granular sludge bed (UASB) reactor operated at 30 °C. The UASB reactor was inoculated with anaerobic granular sludge and fed with lactate as carbon source and electron donor at an organic loading rate of 0.6 g COD L −1 d −1 . After establishing efficient and stable COD removal, the reactor was fed with 10 mg TeO 3 2− L −1 for 42 d before increasing the influent concentration to 20 mg TeO 3 2− L −1 . Tellurite removal (98 and 92%, respectively, from 10 and 20 mg Te L −1 ) was primarily mediated through bioreduction and most of the removed Te was retained in the bioreactor. Characterization using XRD, Raman spectroscopy, SEM-EDX and TEM confirmed association of tellurium with the granular sludge, typically in the form of elemental Te(0) deposits. Furthermore, application of an extracellular polymeric substances (EPS) extraction method to the tellurite reducing sludge recovered up to 78% of the tellurium retained in the granular sludge. This study demonstrates for the first time the application of a UASB reactor for continuous tellurite removal from tellurite-containing wastewater coupled to elemental Te(0) recovery.

  3. Copper (II) Removal In Anaerobic Continuous Column Reactor System By Using Sulfate Reducing Bacteria

    Science.gov (United States)

    Bilgin, A.; Jaffe, P. R.

    2017-12-01

    Copper is an essential element for the synthesis of the number of electrons carrying proteins and the enzymes. However, it has a high level of toxicity. In this study; it is aimed to treat copper heavy metal in anaerobic environment by using anaerobic continuous column reactor. Sulfate reducing bacteria culture was obtained in anaerobic medium using enrichment culture method. The column reactor experiments were carried out with bacterial culture obtained from soil by culture enrichment method. The system is operated with continuous feeding and as parallel. In the first rector, only sand was used as packing material. The first column reactor was only fed with the bacteria nutrient media. The same solution was passed through the second reactor, and copper solution removal was investigated by continuously feeding 15-600 mg/L of copper solution at the feeding inlet in the second reactor. When the experiment was carried out by adding the 10 mg/L of initial copper concentration, copper removal in the rate of 45-75% was obtained. In order to determine the use of carbon source during copper removal of mixed bacterial cultures in anaerobic conditions, total organic carbon TOC analysis was used to calculate the change in carbon content, and it was calculated to be between 28% and 75%. When the amount of sulphate is examined, it was observed that it changed between 28-46%. During the copper removal, the amounts of sulphate and carbon moles were equalized and more sulfate was added by changing the nutrient media in order to determine the consumption of sulphate or carbon. Accordingly, when the concentration of added sulphate is increased, it is calculated that between 35-57% of sulphate is spent. In this system, copper concentration of up to 15-600 mg / L were studied.

  4. Fluidized Bed Reactor as Solid State Fermenter

    Directory of Open Access Journals (Sweden)

    Krishnaiah, K.

    2005-01-01

    Full Text Available Various reactors such as tray, packed bed, rotating drum can be used for solid-state fermentation. In this paper the possibility of fluidized bed reactor as solid-state fermenter is considered. The design parameters, which affect the performances are identified and discussed. This information, in general can be used in the design and the development of an efficient fluidized bed solid-state fermenter. However, the objective here is to develop fluidized bed solid-state fermenter for palm kernel cake conversion into enriched animal and poultry feed.

  5. Performance of a continuously operated flocculent sludge UASB reactor with slaughterhouse wastewater

    Energy Technology Data Exchange (ETDEWEB)

    Sayed, S.; Zeeuw, W. de

    1988-01-01

    This investigation was carried out to assess the performance of a continuously operated, one-stage, flocculent sludge upflow anaerobic sludge blanket (UASB) reactor treating slaughterhouse wastewater at a process temperature of 30/sup 0/C. The results indicate that the type of substrate ingredients, coarse suspended solids, colloidal and soluble compounds in the wastewater, affect the performance of the reactor because of different mechanisms involved in their removal and their subsequent conversion into methane. Two different mechanisms are distinguished. An entrapment mechanism prevails for the elimination of coarse suspended solids while an adsorption mechanism is involved in the removal of the colloidal and soluble fractions of the wastewater. The results obtained lead to the conclusion that the system can satisfactorily handle organic space loads up to 5 kg COD m/sup -3/ day/sup -1/ at 30/sup 0/C. The data indicate, however, that continuing heavy accumulation of substrate components in the reactor is detrimental to the stability of the anaerobic treatment process as the accumulation can lead to sludge flotation and consequently to a complete loss of the active biomass from the reactor.

  6. Removal of natural organic matter and arsenic from water by electrocoagulation/flotation continuous flow reactor.

    Science.gov (United States)

    Mohora, Emilijan; Rončević, Srdjan; Dalmacija, Božo; Agbaba, Jasmina; Watson, Malcolm; Karlović, Elvira; Dalmacija, Milena

    2012-10-15

    The performance of the laboratory scale electrocoagulation/flotation (ECF) reactor in removing high concentrations of natural organic matter (NOM) and arsenic from groundwater was analyzed in this study. An ECF reactor with bipolar plate aluminum electrodes was operated in the horizontal continuous flow mode. Electrochemical and flow variables were optimized to examine ECF reactor contaminants removal efficiency. The optimum conditions for the process were identified as groundwater initial pH 5, flow rate=4.3 l/h, inter electrode distance=2.8 cm, current density=5.78 mA/cm(2), A/V ratio=0.248 cm(-1). The NOM removal according to UV(254) absorbance and dissolved organic matter (DOC) reached highest values of 77% and 71% respectively, relative to the raw groundwater. Arsenic removal was 85% (6.2 μg As/l) relative to raw groundwater, satisfying the drinking water standards. The specific reactor electrical energy consumption was 17.5 kWh/kg Al. The specific aluminum electrode consumption was 66 g Al/m(3). According to the obtained results, ECF in horizontal continuous flow mode is an energy efficient process to remove NOM and arsenic from groundwater. Copyright © 2012 Elsevier B.V. All rights reserved.

  7. Ammonia tolerant enriched methanogenic cultures as bioaugmentation inocula to alleviate ammonia inhibition in continuous anaerobic reactors

    DEFF Research Database (Denmark)

    Fotidis, Ioannis; Wang, Han; Angelidaki, Irini

    Ammonia is the most common inhibitor of anaerobic digestion (AD) process, resulting in suboptimal exploitation of the biogas potential of the feedstocks, causing significant economic losses to the biogas plants. Ammonia is mainly inhibiting the aceticlastic methanogens, while the hydrogenotrophic...... methanogens are more robust to ammonia toxicity effect. It has been shown that bioaugmentation of a pure strain of a hydrogenotrophic methanogen (i.e. Methanoculleus bourgensis) in an ammonia inhibited continuous anaerobic reactor can improve methane production more than 30%. Nevertheless, cultivation...... tolerant methanogenic culture as potential bioaugmentation inoculum in a continuous stirred tank reactor (CSTR) operating under “inhibited steady-state”, triggered by high ammonia levels (5 g NH4+-N L-1). The results of the current study established for the first time that bioaugmentation of an enriched...

  8. Biological treatment of phenolic wastewater in an anaerobic continuous stirred tank reactor

    Directory of Open Access Journals (Sweden)

    Firozjaee Taghizade Tahere

    2013-01-01

    Full Text Available In the present study, an anaerobic continuous stirred tank reactor (ACSTR with consortium of mixed culture was operated continuously for a period of 110 days. The experiments were performed with three different hydraulic retention times and by varying initial phenol concentrations between 100 to 1000 mg/L. A maximum phenol removal was observed at a hydraulic retention time (HRT of 4 days, with an organic loading rate (OLR of 170.86 mg/L.d. At this condition, phenol removal rate of 89% was achieved. In addition, the chemical oxygen demand (COD removal corresponds to phenol removal. Additional operating parameters such as pH, MLSS and biogas production rate of the effluents were also measured. The present study provides valuable information to design an anaerobic ACSTR reactor for the biodegradation of phenolic wastewater.

  9. Record of Decision; Continued operation of K, L, and P Reactors, Savannah River Site, Aiken, South Carolina

    International Nuclear Information System (INIS)

    1991-01-01

    The US Department of Energy (DOE) has considered the environmental impacts, benefits and costs, and institutional and programmatic needs associated with continued operation of the Savannah River Site (SRS) reactors, and has decided that it will continue to operate K and L Reactors at SRS, and will terminate operation of P Reactor in the immediate future and maintain it in cold standby. For P Reactor, this will involve the reactor's defueling; storage of its heavy water moderator in tanks in the reactor building; shutdown of reactor equipment and systems in a protected condition to prevent deterioration; and maintenance of the reactor in a defueled, protected status by a skeleton staff, which would permit any future decision to refuel and restart. Currently committed and planned upgrade activities will be discontinued for P Reactor. DOE will proceed with the safety upgrades and management system improvements currently scheduled for K Reactor in its program to satisfy the criteria of the Safety Evaluation Report (SER), and will conduct an Operational Readiness Review (ORR). The satisfaction of the SER criteria and completion of the ORR will demonstrate that the safety and health criteria for the resumption of production have been met. Reactor restart is expected to be in the third quarter of 1991 for K Reactor

  10. Small-scale semi-continuous reactor for the conversion of wood to fuel oil

    Energy Technology Data Exchange (ETDEWEB)

    Eager, R L; Pepper, J M; Mathews, J F

    1983-04-01

    The design and operation of a small-scale semi-continuous reactor to convert aspen wood meal into an oil product is described. Modifications that reduce erosion/corrosion are also presented. Short residence times and relatively low operating pressures have been achieved for the reaction of aspen with CO and H2O in the presence of Na2CO3. Conversions, char formation, and the effect of sodium carbonate concentration on oil product are reported.

  11. Modelling for Temperature Non-Isothermal Continuous Stirred Tank Reactor Using Fuzzy Logic

    OpenAIRE

    Nasser Mohamed Ramli; Mohamad Syafiq Mohamad

    2017-01-01

    Many types of controllers were applied on the continuous stirred tank reactor (CSTR) unit to control the temperature. In this research paper, Proportional-Integral-Derivative (PID) controller are compared with Fuzzy Logic controller for temperature control of CSTR. The control system for temperature non-isothermal of a CSTR will produce a stable response curve to its set point temperature. A mathematical model of a CSTR using the most general operating condition was developed through a set of...

  12. Genetic Algorithm Based PID Controller Tuning Approach for Continuous Stirred Tank Reactor

    OpenAIRE

    A. Jayachitra; R. Vinodha

    2014-01-01

    Genetic algorithm (GA) based PID (proportional integral derivative) controller has been proposed for tuning optimized PID parameters in a continuous stirred tank reactor (CSTR) process using a weighted combination of objective functions, namely, integral square error (ISE), integral absolute error (IAE), and integrated time absolute error (ITAE). Optimization of PID controller parameters is the key goal in chemical and biochemical industries. PID controllers have narrowed down the operating r...

  13. TEMPERATURE CONTROL OF A CONTINUOUS STIRRED TANK REACTOR BY MEANS OF TWO DIFFERENT INTELLIGENT STRATEGIES

    OpenAIRE

    Rahmat, Mohd Fua'ad; Yazdani, Amir Mehdi; Movahed, Mohammad Ahmadi; Mahmoudzadeh, Somaiyeh

    2011-01-01

    Continues Stirred Tank Reactor (CSTR) is an important subject in chemical process and offering a diverse range of researches in the area of the chemical and control engineering. Various control approaches have been applied on CSTR to control its parameters. This paper presents two different control strategies based on the combination of a novel socio-political optimization algorithm, called Imperialist Competitive Algorithm (ICA), and concept of the gain scheduling performed by means of the l...

  14. Study on improvement of continuous hydrogen production by photosynthetic biofilm in interior illuminant reactor.

    Science.gov (United States)

    Liu, Wenhui; Yuan, Linjiang; Wei, Bo

    2016-09-01

    In the present study, a new type of interior optical fiber illuminating reactor was developed for H2 production to solve the problem of luminous intensity attenuation at the center portion of a reactor, and an immobilization technique was used to enhance the stability of a continuous hydrogen production process with attached photosynthetic bacteria, using glucose as a sole carbon substrate for the indigenous photosynthetic bacteria (PSB) Rhodopseudomonas palustris SP-6. Results of the experiments showed that the interior optical fiber illuminating reactor produces H2 more efficiently and productively than the exterior light source reactor, with the cumulative H2 production, the maximum H2 production rate and H2 yield increased by 813ml, 11.3ml l-1 h-1 and 22.3%, respectively. The stability of the product of continuous hydrogen was realized by immobilizing PSB on the surface of powder active carbon(PAC). After adding the dosage of 2.0g l-1 PAC, the continuous steady operation of H2 production gave a high H2 yield of 1.398 mol H2 mol-1 glucose and an average H2 production rate of 35.1ml l-1 h-1 illuminating with a single interior optical fiber light source. Meanwhile, a higher H2 yield of 1.495 mol H2 mol-1 glucose and an average H2 production rate of 38.7ml l-1 h-1 were attained illuminating with a compound lamp in the continuous H2 production for 20 days.

  15. Study of optimal operation for producing onion vinegar using two continuously stirred tank reactors

    OpenAIRE

    小林, 秀彰; 山口, 文; 富田, 弘毅; 管野, 亨; 小林, 正義; KOBAYASHI, Hideaki; YAMAGUCHI, Kazaru; TOMITA, Koki; KANNO, Tohru; KOBAYASHI, Masayoshi

    1997-01-01

     Onion vinegar was produced using a 2-stage continuously stirred tank reactor. Regarding the alcohol fermentation and the acetic acid fermentation examined in this study, the immobilized cells on porous ceramics offered stable production of alcohol and acetic acid for long periods of 300 and 700 days, respectively. Compared with the steady-state operation method, the temperature-change forced-cyclic operation method increased ethanol yield of alcohol fermentation by a maximum of 15%. Acetic a...

  16. Advanced reactors and novel reactions for the conversion of triglyceride based oils into high quality renewable transportation fuels

    Science.gov (United States)

    Linnen, Michael James

    , a tubular cracking reactor was developed that could operate continuously without coke formation. The design also was proven to be scalable. Yields from the reactor were determined under a variety of conditions in order to predict the outputs from the NCP and to establish relationships/correlations between operating parameters and the product distribution. These studies led to the conclusion that the most severe operating conditions which do not induce coking are optimal over the experimental domain. In order to develop economical deoxygenation catalysts for use within the NCP, a series of experiments were performed using nickel catalysts, demonstrating that nickel catalysts could outperform their predecessor, a high cost palladium-based catalyst. A nickel catalyst was then tested in a packed bed reactor in order to determine suitable operating conditions for its commercial utilization in packed bed reactors.

  17. Characterization of a continuous agitated cell reactor for oxygen dependent biocatalysis.

    Science.gov (United States)

    Toftgaard Pedersen, Asbjørn; de Carvalho, Teresa Melo; Sutherland, Euan; Rehn, Gustav; Ashe, Robert; Woodley, John M

    2017-06-01

    Biocatalytic oxidation reactions employing molecular oxygen as the electron acceptor are difficult to conduct in a continuous flow reactor because of the requirement for high oxygen transfer rates. In this paper, the oxidation of glucose to glucono-1,5-lactone by glucose oxidase was used as a model reaction to study a novel continuous agitated cell reactor (ACR). The ACR consists of ten cells interconnected by small channels. An agitator is placed in each cell, which mixes the content of the cell when the reactor body is shaken by lateral movement. Based on tracer experiments, a hydrodynamic model for the ACR was developed. The model consisted of ten tanks-in-series with back-mixing occurring within and between each cell. The back-mixing was a necessary addition to the model in order to explain the observed phenomenon that the ACR behaved as two continuous stirred tank reactors (CSTRs) at low flow rates, while it at high flow rates behaved as the expected ten CSTRs in series. The performance of the ACR was evaluated by comparing the steady state conversion at varying residence times with the conversion observed in a stirred batch reactor of comparable size. It was found that the ACR could more than double the overall reaction rate, which was solely due to an increased oxygen transfer rate in the ACR caused by the intense mixing as a result of the spring agitators. The volumetric oxygen transfer coefficient, k L a, was estimated to be 344 h -1 in the 100 mL ACR, opposed to only 104 h -1 in a batch reactor of comparable working volume. Interestingly, the large deviation from plug flow behavior seen in the tracer experiments was found to have little influence on the conversion in the ACR, since both a plug flow reactor (PFR) model and the backflow cell model described the data sufficiently well. Biotechnol. Bioeng. 2017;114: 1222-1230. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

  18. Diels–Alder reactions of myrcene using intensified continuous-flow reactors

    Directory of Open Access Journals (Sweden)

    Christian H. Hornung

    2017-01-01

    Full Text Available This work describes the Diels–Alder reaction of the naturally occurring substituted butadiene, myrcene, with a range of different naturally occurring and synthetic dienophiles. The synthesis of the Diels–Alder adduct from myrcene and acrylic acid, containing surfactant properties, was scaled-up in a plate-type continuous-flow reactor with a volume of 105 mL to a throughput of 2.79 kg of the final product per day. This continuous-flow approach provides a facile alternative scale-up route to conventional batch processing, and it helps to intensify the synthesis protocol by applying higher reaction temperatures and shorter reaction times.

  19. One-step synthesis of pyridines and dihydropyridines in a continuous flow microwave reactor

    Directory of Open Access Journals (Sweden)

    Mark C. Bagley

    2013-09-01

    Full Text Available The Bohlmann–Rahtz pyridine synthesis and the Hantzsch dihydropyridine synthesis can be carried out in a microwave flow reactor or using a conductive heating flow platform for the continuous processing of material. In the Bohlmann–Rahtz reaction, the use of a Brønsted acid catalyst allows Michael addition and cyclodehydration to be carried out in a single step without isolation of intermediates to give the corresponding trisubstituted pyridine as a single regioisomer in good yield. Furthermore, 3-substituted propargyl aldehydes undergo Hantzsch dihydropyridine synthesis in preference to Bohlmann–Rahtz reaction in a very high yielding process that is readily transferred to continuous flow processing.

  20. Continuous reduction of tellurite to recoverable tellurium nanoparticles using an upflow anaerobic sludge bed (UASB) reactor.

    Science.gov (United States)

    Ramos-Ruiz, Adriana; Sesma-Martin, Juan; Sierra-Alvarez, Reyes; Field, Jim A

    2017-01-01

    According to the U.S. Department of Energy and the European Union, tellurium is a critical element needed for energy and defense technology. Thus methods are needed to recover tellurium from waste streams. The objectives of this study was to determine the feasibility of utilizing upflow anaerobic sludge bed (UASB) reactors to convert toxic tellurite (Te IV ) oxyanions to non-toxic insoluble elemental tellurium (Te 0 ) nanoparticles (NP) that are amendable to separation from aqueous effluents. The reactors were supplied with ethanol as the electron donating substrate to promote the biological reduction of Te IV . One reactor was additionally amended with the redox mediating flavonoid compound, riboflavin (RF), with the goal of enhancing the bioreduction of Te IV . Its performance was compared to a control reactor lacking RF. The continuous formation of Te 0 NPs using the UASB reactors was found to be feasible and remarkably improved by the addition of RF. The presence of this flavonoid was previously shown to enhance the conversion rate of Te IV by approximately 11-fold. In this study, we demonstrated that this was associated with the added benefit of reducing the toxic impact of Te IV towards the methanogenic consortium in the UASB and thus enabled a 4.7-fold higher conversion rate of the chemical oxygen demand. Taken as a whole, this work demonstrates the potential of a methanogenic granular sludge to be applied as a bioreactor technology producing recoverable Te 0 NPs in a continuous fashion. Copyright © 2016 Elsevier Ltd. All rights reserved.

  1. Continuous transesterification of biodiesel in a helicoidal reactor using recycled oil

    International Nuclear Information System (INIS)

    Avellaneda, Fredy; Salvado, Joan

    2011-01-01

    The main problem with biodiesel is the high cost of oils made from oleaginous crops. For this reason, various raw materials have been analysed with a view to reducing production costs and obtaining a product that can compete with the price of petrodiesel. Recycled oil is one of the most promising alternatives in the production of biodiesel because not only is the cheapest raw material but it also avoids the expense of treating the oil as a residue. Another way to reduce costs is to make the process more economical. Conventional technology uses sodium hydroxide as the basic catalyst and large-scale batch reactors, whose mechanical agitation requires high energy consumption due to residence times of at least 60 min and temperatures of 60 C. In this paper we use a recycled pretreated oil to compare conventional transesterification with continuous transesterification in a tubular reactor. In this reactor the reactants (oil, methanol and sodium hydroxide) flow through a helicoidal tube submerged in a heating bath at 60 C. The reactor has five outlets distributed non-uniformly to enable samples to be taken at different reaction times. This is to reduce the reaction time and avoid the need for mechanical agitation. With the aim of improving the quality of the biodiesel obtained, we varied the helicoidal system by incorporating a static micromixer and supplying energy in the form of ultrasound from the heating bath. This reactor produced biodiesel and glycerine at compositions roughly equal to those obtained in the batch process (89% FAME content at 75 min) but did so continuously (2.5 mL/min) and just 13 min after the reactants were integrated in a single line using a T device. Both the oil and the biodiesel were characterized and analysed in accordance with European standard UNE EN14214 for biodiesel. (author)

  2. General empirical model for 60Co generation in pressurized water reactors with continuous refueling

    International Nuclear Information System (INIS)

    Urrutia, G.A.; Blesa, M.A.; Fernandez-Prini, R.; Maroto, A.J.G.

    1984-01-01

    A simplified model is presented that permits one to calculate the average activity on the fuel elements of a reactor that operates under continuous refueling, based on the assumption of crud interchange between fuel element surface and coolant in the form of particulate material only and using the crud specific activity as an empirical parameter determined in plant. The net activity flux from core to out-of-core components is then calculated in the form of parametric curves depending on crud specific activity and rate of particulate release from fuel surface. In pressure vessel reactors, contribution to out-ofcore radionuclide inventory arising in the release of activated materials from core components must be taken into account. The contribution from in situ activation of core components is calculated from the rates of release and the specific activities corresponding to the exposed surface of the component (calculated in a straightforward way on the basis of core geometry and neutron fluxes). The rates of release can be taken from the literature, or in the case of cobalt-rich alloys, can be calculated from experimentally determined cobalt contents of structural components and crud. For pressure vessel reactors operating under continuous refueling, activation of deposited crud and release of activated materials are compared; the latter, in certain cases, may represent a sizable (and even the largest) fraction of the total cobalt activity. It is proposed that the ratio of activities of 59 Fe to 54 Mn may be used as a diagnostic tool for in situ activation of structural materials; available data indicate ratios close to unity for pressure tube heavy water reactors (no in situ activation) and ratios around 4 to 10 for pressure vessel, heavy water reactors

  3. Caffeine degradation by Rhizopus delemar in packed bed column bioreactor using coffee husk as substrate Degradação de cafeína por Rhizopus delemar em biorreator de colunas usando casca de café como substrato

    Directory of Open Access Journals (Sweden)

    Cristiane Vanessa Tagliari

    2003-11-01

    Full Text Available Various microorganisms including bacteria, yeast and fungi can degrade caffeine. There are few publications about caffeine degradation pathway in filamentous fungi, mainly by solid-state fermentation (SSF. Studies were carried out on degradation of caffeine and their metabolites by filamentous fungi in SSF using coffee husk as substrate. The purpose of this work was to investigate the caffeine degradation pathway by Rhizopus delemar in packed bed column fermenter and to compare this degradation metabolism with glass flasks fermentation. The methylxanthines were quantified by HPLC analysis. The experiments were realized with the optimized conditions in previous experiments: pH 6.5, 28ºC, inoculation rate 10(6 spores/g substrate, aeration rate 60 mL/min and initial moisture 73%. Under these conditions, after 72 hous of fermentation was achieved only 0.19% of caffeine and 0.014% of theophylline in the coffee husk. The strain proved to be able for caffeine and theophylline degradation by SSF in packed bed column bioreactor.Diversos microrganismos incluindo bactérias, fungos e leveduras são capazes de assimilar a cafeína de meios sintéticos ou de resíduos de café. Existem poucos trabalhos sobre a via de degradação da cafeína em fungos filamentosos, principalmente por fermentação no estado sólido (FES. Estudos de degradação da cafeína por fungos filamentosos em FES usando casca de café como substrato vêm sendo realizados. O objetivo deste trabalho foi investigar a via de degradação da cafeína por Rhizopus delemar em biorreator de colunas aeradas e comparar este metabolismo de degradação com o da fermentação em frascos de vidro. As metilxantinas foram quantificadas por análises em HPLC. Os experimentos foram realizados com as condições otimizadas previamente: pH 6,5, 28ºC, 10(6 espores/g substrato, vazão de ar 60 mL/min e 73% de umidade inicial. Após 90 horas de fermentação, 65% da cafeína foi reduzida, resultando 0

  4. Continuous radiochemical analysis of fission products in a nuclear reactor water coolant

    International Nuclear Information System (INIS)

    Moskvin, L.N.; Zakharov, L.K.; Leont'ev, G.G.; Mel'nikov, V.A.; Orlenkov, I.S.; Slutskij, G.K.

    1975-01-01

    Method for continuous radiochemical analysis of I, Cs, Ba, Sr and Ce isotopes in a reactor water heat-transfer agent was developed. A continuous two-dimensional chromatographic process of complex mixtures separation of substances proved to be feasible on several parallel sorbent layers, which moved at constant velocities and separated by stationary intermediate collectors. Tests on model solutions containing I, Ce, Cs and Ba isotopes and on heat-carrier samples showed quantitative separation of elements. The results were indicative of a basic possibility of using multisorbent chromatographs for continuous control of multicomponent mixtures, particularly for control of radioactive fission product compositions in water heat-transfer agents in nuclear power plants. A diagram is shown for a two-dimensional chromatographic separation of a multicomponent mixture. Also shown is a flow chart of an installation for continuous control of iodine and cesium isotope activities

  5. Startup and oxygen concentration effects in a continuous granular mixed flow autotrophic nitrogen removal reactor.

    Science.gov (United States)

    Varas, Rodrigo; Guzmán-Fierro, Víctor; Giustinianovich, Elisa; Behar, Jack; Fernández, Katherina; Roeckel, Marlene

    2015-08-01

    The startup and performance of the completely autotrophic nitrogen removal over nitrite (CANON) process was tested in a continuously fed granular bubble column reactor (BCR) with two different aeration strategies: controlling the oxygen volumetric flow and oxygen concentration. During the startup with the control of oxygen volumetric flow, the air volume was adjusted to 60mL/h and the CANON reactor had volumetric N loadings ranging from 7.35 to 100.90mgN/Ld with 36-71% total nitrogen removal and high instability. In the second stage, the reactor was operated at oxygen concentrations of 0.6, 0.4 and 0.2mg/L. The best condition was 0.2 mgO2/L with a total nitrogen removal of 75.36% with a CANON reactor activity of 0.1149gN/gVVSd and high stability. The feasibility and effectiveness of CANON processes with oxygen control was demonstrated, showing an alternative design tool for efficiently removing nitrogen species. Copyright © 2015 Elsevier Ltd. All rights reserved.

  6. Globally linearized control on diabatic continuous stirred tank reactor: a case study.

    Science.gov (United States)

    Jana, Amiya Kumar; Samanta, Amar Nath; Ganguly, Saibal

    2005-07-01

    This paper focuses on the promise of globally linearized control (GLC) structure in the realm of strongly nonlinear reactor system control. The proposed nonlinear control strategy is comprised of: (i) an input-output linearizing state feedback law (transformer), (ii) a state observer, and (iii) an external linear controller. The synthesis of discrete-time GLC controller for single-input single-output diabatic continuous stirred tank reactor (DCSTR) has been studied first, followed by the synthesis of feedforward/feedback controller for the same reactor having dead time in process as well as in disturbance. Subsequently, the multivariable GLC structure has been designed and then applied on multi-input multi-output DCSTR system. The simulation study shows high quality performance of the derived nonlinear controllers. The better-performed GLC in conjunction with reduced-order observer has been compared with the conventional proportional integral controller on the example reactor and superior performance has been achieved by the proposed GLC control scheme.

  7. Evaluation of Continuous Stirred Tank Reactor Performance by Using Radioisotope Tracer

    International Nuclear Information System (INIS)

    Noor Anis Kundari; Djoko Marjanto; Ardhani Dyah W

    2009-01-01

    Research on performance evaluation of continuous stirred tank reactor (CSTR) using radioisotope tracer has been carried out. The aim of research is to assess a validity of assumption that stirring or mixing process in a CSTR is perfect. In order to follow the flow dynamics process of the fluid in the reactor, I-131 was used. The reactor was equipped with four baffles. The fluid/water leaving the reactor was sampled at 13 up to 1393 seconds and analysed its I-131 concentration. The performance of CSTR is expressed as dispersed number (D/uL) as function of retention time and Reynolds number under axial dispersed model. The experimental result show that the relation between the dispersion number and retention time is D/uL = 9X10 -4 (t s * ) 2 - 6.9X10 -1 (t s * ) + 148 and the dispersion number and Reynolds number is D/uL = 65.7 e 0.0003/Re . The dispersion number obtained were much higher than 0.01 that in between 11.08 up to 21.4. That mean the mixing process occurred in the CSTR can be assumed to be ideal. (author)

  8. Analysis of transition to fuel cycle system with continuous recycling in fast and thermal reactors - 5060

    International Nuclear Information System (INIS)

    Passereini, S.; Feng, B.; Fei, T.; Kim, T.K.; Taiwo, T.A.; Brown, N.R.; Cuadra, A.

    2015-01-01

    A recent Evaluation and Screening study of nuclear fuel cycle options identified a few groups of options as most promising. One of these most promising Evaluation Groups (EGs) is characterized by the continuous recycling of uranium (U) and transuranics (TRU) with natural uranium feed in both fast and thermal critical reactors. This evaluation group, designated as EG30, is represented by an example fuel cycle option that employs a two-technology, two-stage fuel cycle system. The first stage involves the continuous recycling of co-extracted U/TRU in Sodium-cooled Fast Reactors (SFRs) with metallic fuel and breeding ratio greater than 1. The second stage involves the use of the surplus TRU in Mixed Oxide (MOX) fuel in Pressurized Water Reactors that are MOX-capable (MOX-PWRs). This paper presents and discusses preliminary fuel cycle analysis results from the fuel cycle codes VISION and DYMOND for the transition to this fuel cycle option from the current once-through cycle in the United States (U.S.) that consists of Light Water Reactors (LWRs) that only use conventional UO 2 fuel. The analyses in this paper are applicable for a constant 100 GWe capacity, roughly the size of the U.S. nuclear fleet. Two main strategies for the transition to EG30 were analyzed: 1) deploying both SFRs and MOX-PWRs in parallel or 2) deploying them in series with the SFR fleet first. With an estimated retirement schedule for the existing LWRs, an assumed reactor lifetime of 60 years, and no growth, the nuclear system fully transitions to the new fuel cycle within 100 years for both strategies without SFR fuel shortages. Compared to the once-through cycle, transition to the SFR/MOX-PWR fleet with continuous recycle was shown to offer significant reductions in uranium consumption and waste disposal requirements. In addition, these initial calculations revealed a few notable modeling and strategy questions regarding how recycled resources are allocated, reactors that can switch between

  9. Modelling of slaughterhouse solid waste anaerobic digestion: determination of parameters and continuous reactor simulation.

    Science.gov (United States)

    López, Iván; Borzacconi, Liliana

    2010-10-01

    A model based on the work of Angelidaki et al. (1993) was applied to simulate the anaerobic biodegradation of ruminal contents. In this study, two fractions of solids with different biodegradation rates were considered. A first-order kinetic was used for the easily biodegradable fraction and a kinetic expression that is function of the extracellular enzyme concentration was used for the slowly biodegradable fraction. Batch experiments were performed to obtain an accumulated methane curve that was then used to obtain the model parameters. For this determination, a methodology derived from the "multiple-shooting" method was successfully used. Monte Carlo simulations allowed a confidence range to be obtained for each parameter. Simulations of a continuous reactor were performed using the optimal set of model parameters. The final steady-states were determined as functions of the operational conditions (solids load and residence time). The simulations showed that methane flow peaked at a flow rate of 0.5-0.8 Nm(3)/d/m(reactor)(3) at a residence time of 10-20 days. Simulations allow the adequate selection of operating conditions of a continuous reactor. (c) 2010 Elsevier Ltd. All rights reserved.

  10. Using Flow Electrodes in Multiple Reactors in Series for Continuous Energy Generation from Capacitive Mixing

    KAUST Repository

    Hatzell, Marta C.

    2014-12-09

    Efficient conversion of “mixing energy” to electricity through capacitive mixing (CapMix) has been limited by low energy recoveries, low power densities, and noncontinuous energy production resulting from intermittent charging and discharging cycles. We show here that a CapMix system based on a four-reactor process with flow electrodes can generate constant and continuous energy, providing a more flexible platform for harvesting mixing energy. The power densities were dependent on the flow-electrode carbon loading, with 5.8 ± 0.2 mW m–2 continuously produced in the charging reactor and 3.3 ± 0.4 mW m–2 produced in the discharging reactor (9.2 ± 0.6 mW m–2 for the whole system) when the flow-electrode carbon loading was 15%. Additionally, when the flow-electrode electrolyte ion concentration increased from 10 to 20 g L–1, the total power density of the whole system (charging and discharging) increased to 50.9 ± 2.5 mW m–2.

  11. Partial nitrification using aerobic granules in continuous-flow reactor: rapid startup.

    Science.gov (United States)

    Wan, Chunli; Sun, Supu; Lee, Duu-Jong; Liu, Xiang; Wang, Li; Yang, Xue; Pan, Xiangliang

    2013-08-01

    This study applied a novel strategy to rapid startup of partial nitrification in continuous-flow reactor using aerobic granules. Mature aerobic granules were first cultivated in a sequencing batch reactor at high chemical oxygen demand in 16 days. The strains including the Pseudoxanthomonas mexicana strain were enriched in cultivated granules to enhance their structural stability. Then the cultivated granules were incubated in a continuous-flow reactor with influent chemical oxygen deamnad being stepped decreased from 1,500 ± 100 (0-19 days) to 750 ± 50 (20-30 days), and then to 350 ± 50 mg l(-1) (31-50 days); while in the final stage 350 mg l(-1) bicarbonate was also supplied. Using this strategy the ammonia-oxidizing bacterium, Nitrosomonas europaea, was enriched in the incubated granules to achieve partial nitrification efficiency of 85-90% since 36 days and onwards. The partial nitrification granules were successfully harvested after 52 days, a period much shorter than those reported in literature. Copyright © 2013 Elsevier Ltd. All rights reserved.

  12. Nitrite accumulation in continuous-flow partial autotrophic denitrification reactor using sulfide as electron donor.

    Science.gov (United States)

    Liu, Chunshuang; Li, Wenfei; Li, Xuechen; Zhao, Dongfeng; Ma, Bin; Wang, Yongqiang; Liu, Fang; Lee, Duu-Jong

    2017-11-01

    The nitrite accumulation in handling nitrate and sulfide-laden wastewater in a continuous-flow upflow anaerobic sludge blanket reactor was studied. At sulfide/nitrate-nitrogen ratio of 1:0.76 and loading rates of 1.2kg-Sm -3 d -1 and 0.4kg-Nm -3 d -1 , the elemental sulfur and nitrite accumulation rates peaked at 90% and 70%, respectively, with Acrobacter, Azoarcus and Thauera presenting the functional strains in the studied reactor. The accumulated nitrite was proposed a promising feedstock for anaerobic ammonia oxidation process. An integrated partial autotrophic denitrification-anaerobic ammonia oxidation-aeration process for handling the ammonia and sulfide-laden wastewaters is proposed for further studies. Copyright © 2017 Elsevier Ltd. All rights reserved.

  13. Fluid dynamic analysis of a continuous stirred tank reactor for technical optimization of wastewater digestion.

    Science.gov (United States)

    Hurtado, F J; Kaiser, A S; Zamora, B

    2015-03-15

    Continuous stirred tank reactors (CSTR) are widely used in wastewater treatment plants to reduce the organic matter and microorganism present in sludge by anaerobic digestion. The present study carries out a numerical analysis of the fluid dynamic behaviour of a CSTR in order to optimize the process energetically. The characterization of the sludge flow inside the digester tank, the residence time distribution and the active volume of the reactor under different criteria are determined. The effects of design and power of the mixing system on the active volume of the CSTR are analyzed. The numerical model is solved under non-steady conditions by examining the evolution of the flow during the stop and restart of the mixing system. An intermittent regime of the mixing system, which kept the active volume between 94% and 99%, is achieved. The results obtained can lead to the eventual energy optimization of the mixing system of the CSTR. Copyright © 2014 Elsevier Ltd. All rights reserved.

  14. Continuous-flow stirred-tank reactor 20-L demonstration test: Final report

    International Nuclear Information System (INIS)

    Lee, D.D.; Collins, J.L.

    2000-01-01

    One of the proposed methods of removing the cesium, strontium, and transuranics from the radioactive waste storage tanks at Savannah River is the small-tank tetraphenylborate (TPB) precipitation process. A two-reactor-in-series (15-L working volume each) continuous-flow stirred-tank reactor (CSTR) system was designed, constructed, and installed in a hot cell to test the Savannah River process. The system also includes two cross-flow filtration systems to concentrate and wash the slurry produced in the process, which contains the bulk of radioactivity from the supernatant processed through the system. Installation, operational readiness reviews, and system preparation and testing were completed. The first test using the filtration systems, two CSTRs, and the slurry concentration system was conducted over a 61-h period with design removal of Cs, Sr, and U achieved. With the successful completion of Test 1a, the following tests, 1b and 1c, were not required

  15. Stability criteria and critical runway conditions of propylene glycol manufacture in a continuous stirred tank reactor

    Directory of Open Access Journals (Sweden)

    Miguel Ángel Gómez

    2015-05-01

    Full Text Available Here, a new method for the analysis of the steady state and the safety operational conditions of the hydrolysis of propylene oxide with excess of water, in a Continuous Stirred Tank Reactor (CSTR, was developed. For industrial operational typical values, at first, the generated and removed heat balances were examined. Next, the effect of coolant fluid temperature in the critical ignition and extinction temperatures (TCI and TCE, respectively was analyzed. The influence of the heat exchange parameter (hS on coolant and critical temperatures was also studied. Finally, the steady state operation areas were defined. The existence of multiple stable states was recognized when the heat exchange parameter was in the range 6.636 < hS kJ/(min.K < 11.125. Unstable operation area was located between the TCI and TCE values, restricting the reactor operation area to the low stable temperatures.

  16. Nonequilibrium chemical instabilities in continuous flow stirred tank reactors: The effect of stirring

    International Nuclear Information System (INIS)

    Horsthemke, W.; Hannon, L.

    1984-01-01

    We present a stochastic model for stirred chemical reactors. In the limiting case of practical interest, i.e., fast stirring, we solve for the characteristic function in steady state and derive expressions for the stationary moments through a perturbation expansion. Moments are explicitly calculated for a generic model of bistable behavior. We find that stirring decreases the area of the bistable region essentially by changing the point of transition from the high reaction rate state to the low reaction rate state. This is in remarkable agreement with the experimental findings of Roux, et al. Our results indicate that stirring should not be considered simply as an ''enhanced diffusion'' process and that nucleation plays only a minor role in transitions between multiple steady states in a continuous flow stirred tank reactor (CSTR)

  17. Continuous-flow stirred-tank reactor 20-L demonstration test: Final report

    Energy Technology Data Exchange (ETDEWEB)

    Lee, D.D.; Collins, J.L.

    2000-02-01

    One of the proposed methods of removing the cesium, strontium, and transuranics from the radioactive waste storage tanks at Savannah River is the small-tank tetraphenylborate (TPB) precipitation process. A two-reactor-in-series (15-L working volume each) continuous-flow stirred-tank reactor (CSTR) system was designed, constructed, and installed in a hot cell to test the Savannah River process. The system also includes two cross-flow filtration systems to concentrate and wash the slurry produced in the process, which contains the bulk of radioactivity from the supernatant processed through the system. Installation, operational readiness reviews, and system preparation and testing were completed. The first test using the filtration systems, two CSTRs, and the slurry concentration system was conducted over a 61-h period with design removal of Cs, Sr, and U achieved. With the successful completion of Test 1a, the following tests, 1b and 1c, were not required.

  18. Modifications in the operational conditions of the IEA-R1 reactor under continuous 48 hours operation

    International Nuclear Information System (INIS)

    Moreira, Joao Manoel Losada; Frajndlich, Roberto

    1995-01-01

    This work shows the required changes in the IEA-R1 reactor for operation at 2 Mw, 48 hours continuously. The principal technical change regards the operating conditions of the reactor, namely, the required excess reactivity which now will amount to 4800 pcm in order to compensate the Xe poisoning at equilibrium at 2 Mw. (author). 6 refs, 1 fig, 1 tab

  19. Ozo-Dyes mixture degradation in a fixed bed biofilm reactor packed with volcanic porous rock

    International Nuclear Information System (INIS)

    Contreras-Blancas, E.; Cobos-Vasconcelos, D. de los; Juarez-Ramirez, C.; Poggi-Varaldo, H. M.; Ruiz-Ordaz, N.; Galindez-Mayer, J.

    2009-01-01

    Textile industries discharge great amounts of dyes and dyeing-process auxiliaries, which pollute streams and water bodies. Several dyes, especially the ones containing the azo group, can cause harmful effects to different organisms including humans. Through bacterial and mammalian tests, azo dyes or their derived aromatic amines have shown cell genotoxicity. The purpose of this work was to evaluate the effect of air flow rate on azo-dyes mixture biodegradation by a microbial community immobilized in a packed bed reactor. (Author)

  20. Ozo-Dyes mixture degradation in a fixed bed biofilm reactor packed with volcanic porous rock

    Energy Technology Data Exchange (ETDEWEB)

    Contreras-Blancas, E.; Cobos-Vasconcelos, D. de los; Juarez-Ramirez, C.; Poggi-Varaldo, H. M.; Ruiz-Ordaz, N.; Galindez-Mayer, J.

    2009-07-01

    Textile industries discharge great amounts of dyes and dyeing-process auxiliaries, which pollute streams and water bodies. Several dyes, especially the ones containing the azo group, can cause harmful effects to different organisms including humans. Through bacterial and mammalian tests, azo dyes or their derived aromatic amines have shown cell genotoxicity. The purpose of this work was to evaluate the effect of air flow rate on azo-dyes mixture biodegradation by a microbial community immobilized in a packed bed reactor. (Author)

  1. Inhibitors degradation and microbial response during continuous anaerobic conversion of hydrothermal liquefaction wastewater.

    Science.gov (United States)

    Si, Buchun; Li, Jiaming; Zhu, Zhangbing; Shen, Mengmeng; Lu, Jianwen; Duan, Na; Zhang, Yuanhui; Liao, Qiang; Huang, Yun; Liu, Zhidan

    2018-07-15

    One critical challenge of hydrothermal liquefaction (HTL) is its complex aqueous product, which has a high concentration of organic pollutants (up to 100gCOD/L) and diverse fermentation inhibitors, such as furfural, phenolics and N-heterocyclic compounds. Here we report continuous anaerobic digestion of HTL wastewater via an up-flow anaerobic sludge bed reactor (UASB) and packed bed reactor (PBR). Specifically, we investigated the transformation of fermentation inhibitors and microbial response. GC-MS identified the complete degradation of furfural and 5-hydroxymethylfurfural (5-HMF), and partial degradation (54.0-74.6%) of organic nitrogen and phenolic compounds, including 3-hydroxypyridine, phenol and 4-ethyl-phenol. Illumina MiSeq sequencing revealed that the bacteria families related to detoxification increased in response to the HTL aqueous phase. In addition, the increase of acetate-oxidizing bacteria in UASB and acetogens in PBR showed a strengthened acetogenesis. As for the archaeal communities, an increase in hydrogenotrophic methanogens was observed. Based on GC-MS/HPLC and microbial analysis, we speculate that dominant fermentation inhibitors were transformed into intermediates (Acetyl-CoA and acetate), further contributing to biomethane formation. Copyright © 2018 Elsevier B.V. All rights reserved.

  2. Fault Diagnosis and Tolerant Control Using Observer Banks Applied to Continuous Stirred Tank Reactor

    Directory of Open Access Journals (Sweden)

    Martin F. Pico

    2017-04-01

    Full Text Available This paper focuses on studying the problem of fault tolerant control (FTC, including a detailed fault detection and diagnosis (FDD module using observer banks which consists of output and unknown input observers applied to a continuous stirred tank reactor (CSTR. The main objective of this paper is to use a FDD module here proposed to estimate the fault in order to apply this result in a FTC system (FTCS, to prevent a lost of of the control system performance. The benefits of the observer bank and fault adaptation here studied are illustrated by numerical simulations which assumes faults in manipulated and measuring elements of the CSTR.

  3. Tetraphenylborate Catalyst Development for the Oak Ridge National Laboratory 20-L Continuously Stirred Tank Reactor Demonstration

    International Nuclear Information System (INIS)

    Barnes, M.J.

    2001-01-01

    The Salt Disposition Systems Engineering Team identified Small Tank Tetraphenylborate Precipitation as one of the three alternatives to replace the In-Tank Precipitation Facility at the Savannah River Site. The proposed design incorporates two continuous stirred tank reactors (CSTR) a concentrate tank and a sintered metal crossflow filter. Previous use of tetraphenylborate in batch operation and testing demonstrated the ability of the feed material to catalyze the decomposition of tetraphenylborate. The Small Tank Tetraphenylborate Precipitation design seeks to overcome the processing limitation of the unwanted reaction by rapid throughput and temperature control. Nitrogen inerting of the vapor space helps mitigate any safety (i.e., flammable) concerns of the reaction

  4. Continuous method for refining sodium. [for use in LMFBR type reactors

    Energy Technology Data Exchange (ETDEWEB)

    Batoux, B; Laurent-Atthalin, A; Salmon, M

    1973-11-16

    The invention relates to a refining method according to which commercial sodium provides a high purity sodium with, in particular, a very small calcium content. The method consists in continuously feeding a predetermined amount of sodium peroxide into a sodium stream, mixing and causing said sodium peroxide to reach with sodium at an appropriate temperature, and, finally, separating the reaction products from sodium by decanting and filtering same. The thus obtained high purity sodium meets the requirements of atomic industries in particular, in view of its possible use as coolant in nuclear reactors of the ''breeder'' type.

  5. Continuous API-crystal coating via coacervation in a tubular reactor.

    Science.gov (United States)

    Besenhard, M O; Thurnberger, A; Hohl, R; Faulhammer, E; Rattenberger, J; Khinast, J G

    2014-11-20

    We present a proof-of-concept study of a continuous coating process of single API crystals in a tubular reactor using coacervation as a microencapsulation technique. Continuous API crystal coating can have several advantages, as in a single step (following crystallization) individual crystals can be prepared with a functional coating, either to change the release behavior, to protect the API from gastric juice or to modify the surface energetics of the API (i.e., to tailor the hydrophobic/hydrophilic characteristics, flowability or agglomeration tendency, etc.). The coating process was developed for the microencapsulation of a lipophilic core material (ibuprofen crystals of 20 μm- to 100 μm-size), with either hypromellose phthalate (HPMCP) or Eudragit L100-55. The core material was suspended in an aqueous solution containing one of these enteric polymers, fed into the tubing and mixed continuously with a sodium sulfate solution as an antisolvent to induce coacervation. A subsequent temperature treatment was applied to optimize the microencapsulation of crystals via the polymer-rich coacervate phase. Cross-linking of the coating shell was achieved by mixing the processed material with an acidic solution (pH<3). Flow rates, temperature profiles and polymer-to-antisolvent ratios had to be tightly controlled to avoid excessive aggregation, leading to pipe plugging. This work demonstrates the potential of a tubular reactor design for continuous coating applications and is the basis for future work, combining continuous crystallization and coating. Copyright © 2014 Elsevier B.V. All rights reserved.

  6. Cassava Stillage Treatment by Thermophilic Anaerobic Continuously Stirred Tank Reactor (CSTR)

    Science.gov (United States)

    Luo, Gang; Xie, Li; Zou, Zhonghai; Zhou, Qi

    2010-11-01

    This paper assesses the performance of a thermophilic anaerobic Continuously Stirred Tank Reactor (CSTR) in the treatment of cassava stillage under various organic loading rates (OLRs) without suspended solids (SS) separation. The reactor was seeded with mesophilic anaerobic granular sludge, and the OLR increased by increments to 13.80 kg COD/m3/d (HRT 5d) over 80 days. Total COD removal efficiency remained stable at 90%, with biogas production at 18 L/d (60% methane). Increase in the OLR to 19.30 kg COD/m3/d (HRT 3d), however, led to a decrease in TCOD removal efficiency to 79% due to accumulation of suspended solids and incomplete degradation after shortened retention time. Reactor performance subsequently increased after OLR reduction. Alkalinity, VFA and pH levels were not significantly affected by OLR variation, indicating that no additional alkaline or pH adjustment is required. More than half of the SS in the cassava stillage could be digested in the process when HRT was 5 days, which demonstrated the suitability of anaerobic treatment of cassava stillage without SS separation.

  7. Continuous fermentative hydrogen production from coffee drink manufacturing wastewater by applying UASB reactor

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Kyung-Won; Shin, Hang-Sik [Department of Civil and Environmental Engineering, KAIST, 373-1 Guseong-dong, Yuseong-gu, Daejeon 305-701 (Korea, Republic of); Kim, Dong-Hoon [Department of Civil and Environmental Engineering, University of Windsor, 401 Sunset Ave., Essex Hall, Windsor, Ontario (Canada)

    2010-12-15

    The feasibility of continuous H{sub 2} production from coffee drink manufacturing wastewater (CDMW) was tested in two different types of reactors: a completely-stirred tank reactor (CSTR) and an up-flow anaerobic sludge blanket reactor (UASBr). While the performance in CSTR was limited, it was significantly enhanced in UASBr. The maximum H{sub 2} yield of 1.29 mol H{sub 2}/mol hexose{sub added} was achieved at HRT of 6 h in UASBr operation. Non-hydrogenic, lactic acid was the dominant in CSTR, while butyric and caproic acids in UASBr. As caproic acid is generated by consuming acetic and butyric acids, all of which are related to H{sub 2} production, the presence of caproic acid in the broth also indicates H{sub 2} production, yielding 1.33 mol H{sub 2}/glucose. It was speculated that the enhanced performance in UASBr was attributed to the high concentration of biomass over 60,000 mg VSS/L in the blanket zone, which provided insufficient substrate for indigenous lactic acid bacteria (LAB) to survive. The abundance of LAB in CDMW was confirmed by natural fermentation of CDMW. That is without the addition of external inoculum, CDMW was mainly fermented into lactic acid under mesophilic condition. For the first time ever, H{sub 2} producing granules (HPG) with diameters of 2.1 mm were successfully formed by using actual waste as a substrate. (author)

  8. PERMEABILITY REDUCTION PHENOMENA IN PACKED BEDS, FIBER MATS, AND WET WEBS OF PAPER EXPOSED TO FLOW OF LIQUIDS AND SUSPENSIONS: A REVIEW

    Directory of Open Access Journals (Sweden)

    Martin A. Hubbe

    2009-02-01

    Full Text Available Filter media, including those prepared from cellulosic materials, often suffer from permeability loss during continued use. To help understand such issues, one can take advantage of an extensive body of related research in such fields as industrial filtration, water purification, enhanced oil recovery, chromatography, paper manufacture, and the leaching of pollutants from impoundments. Though the mechanisms that appear to govern permeability-loss phenomena depend a lot on the details of various applications, the published research has revealed a number of common features. In particular, flow through a porous bed or fiber mat can be markedly reduced by deposition of particles or colloidal matter in positions that either block or partially restrict fluid flow. Progress has been achieved in the development of mechanistic models, as well as the use of such models in numerical simulations to explain various experimental findings. Further research of this type needs to be applied to cellulosic materials, which tend to be much more elongated in comparison to the bed materials and suspended matter considered most often by most researchers active in research related to permeability loss.

  9. Integration of Methane Steam Reforming and Water Gas Shift Reaction in a Pd/Au/Pd-Based Catalytic Membrane Reactor for Process Intensification.

    Science.gov (United States)

    Castro-Dominguez, Bernardo; Mardilovich, Ivan P; Ma, Liang-Chih; Ma, Rui; Dixon, Anthony G; Kazantzis, Nikolaos K; Ma, Yi Hua

    2016-09-19

    Palladium-based catalytic membrane reactors (CMRs) effectively remove H₂ to induce higher conversions in methane steam reforming (MSR) and water-gas-shift reactions (WGS). Within such a context, this work evaluates the technical performance of a novel CMR, which utilizes two catalysts in series, rather than one. In the process system under consideration, the first catalyst, confined within the shell side of the reactor, reforms methane with water yielding H₂, CO and CO₂. After reforming is completed, a second catalyst, positioned in series, reacts with CO and water through the WGS reaction yielding pure H₂O, CO₂ and H₂. A tubular composite asymmetric Pd/Au/Pd membrane is situated throughout the reactor to continuously remove the produced H₂ and induce higher methane and CO conversions while yielding ultrapure H₂ and compressed CO₂ ready for dehydration. Experimental results involving (i) a conventional packed bed reactor packed (PBR) for MSR, (ii) a PBR with five layers of two catalysts in series and (iii) a CMR with two layers of two catalysts in series are comparatively assessed and thoroughly characterized. Furthermore, a comprehensive 2D computational fluid dynamics (CFD) model was developed to explore further the features of the proposed configuration. The reaction was studied at different process intensification-relevant conditions, such as space velocities, temperatures, pressures and initial feed gas composition. Finally, it is demonstrated that the above CMR module, which was operated for 600 h, displays quite high H₂ permeance and purity, high CH₄ conversion levels and reduced CO yields.

  10. Bioremoval of trivalent chromium using Bacillus biofilms through continuous flow reactor

    International Nuclear Information System (INIS)

    Sundar, K.; Sadiq, I. Mohammed; Mukherjee, Amitava; Chandrasekaran, N.

    2011-01-01

    Highlights: ► Effective bioremoval of Cr(III) using bacterial biofilms. ► Simplified bioreactor was fabricated for the biofilm development and Cr(III) removal. ► Economically feasible substrate like coarse sand and pebbles were used. - Abstract: Present study deals with the applicability of bacterial biofilms for the bioremoval of trivalent chromium from tannery effluents. A continuous flow reactor was designed for the development of biofilms on different substrates like glass beads, pebbles and coarse sand. The parameters for the continuous flow reactor were 20 ml/min flow rate at 30 °C, pH4. Biofilm biomass on the substrates was in the following sequence: coarse sand > pebbles > glass beads (4.8 × 10 7 , 4.5 × 10 7 and 3.5 × 10 5 CFU/cm 2 ), which was confirmed by CLSM. Biofilms developed using consortium of Bacillus subtilis and Bacillus cereus on coarse sand had more surface area and was able to remove 98% of Cr(III), SEM-EDX proved 92.60% Cr(III) adsorption on biofilms supported by coarse sand. Utilization of Bacillus biofilms for effective bioremoval of Cr(III) from chrome tanning effluent could be a better option for tannery industry, especially during post chrome tanning operation.

  11. Biological hydrogen production in continuous stirred tank reactor systems with suspended and attached microbial growth

    Energy Technology Data Exchange (ETDEWEB)

    Ren, Nan-Qi; Tang, Jing; Liu, Bing-Feng; Guo, Wan-Qian [State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, No.202 Haihe Road, Harbin 150090 (China)

    2010-04-15

    Fermentative H{sub 2} production in continuous stirred tank reactor (CSTR) system with bacteria attached onto granular activated carbon (GAC) was designed to produce H{sub 2} continuously. The H{sub 2} production performances of CSTR with suspended and attached-sludge from molasses were examined and compared at various organic loading rates (8-40 g COD/L/d) at hydraulic retention time of 6 h under mesophilic conditions (35 C). Both reactor systems achieved ethanol-type fermentation in the pH ranges 4.5-4.8 and 3.8-4.4, respectively, while ORP ranges from -450 to -470 mV and from -330 to -350 mV, respectively. The hydrogen production rate in the attached system was higher compared to that of the suspended system (9.72 and 6.65 L/d/L, respectively) while specific hydrogen production rate of 5.13 L/g VSS/d was higher in the suspended system. The attached-sludge CSTR is more stable than the suspended-sludge CSTR with regard to hydrogen production, pH, substrate utilization efficiency and metabolic products (e.g., volatile fatty acids and ethanol) during the whole test. (author)

  12. Evaluation of an integrated continuous stirred microbial electrochemical reactor: Wastewater treatment, energy recovery and microbial community.

    Science.gov (United States)

    Wang, Haiman; Qu, Youpeng; Li, Da; Zhou, Xiangtong; Feng, Yujie

    2015-11-01

    A continuous stirred microbial electrochemical reactor (CSMER) was developed by integrating anaerobic digestion (AD) and microbial electrochemical system (MES). The system was capable of treating high strength artificial wastewater and simultaneously recovering electric and methane energy. Maximum power density of 583±9, 562±7, 533±10 and 572±6 mW m(-2) were obtained by each cell in a four-independent circuit mode operation at an OLR of 12 kg COD m(-3) d(-1). COD removal and energy recovery efficiency were 87.1% and 32.1%, which were 1.6 and 2.5 times higher than that of a continuous stirred tank reactor (CSTR). Larger amount of Deltaproteobacteria (5.3%) and hydrogenotrophic methanogens (47%) can account for the better performance of CSMER, since syntrophic associations among them provided more degradation pathways compared to the CSTR. Results demonstrate the CSMER holds great promise for efficient wastewater treatment and energy recovery. Copyright © 2015 Elsevier Ltd. All rights reserved.

  13. New sampling method in continuous energy Monte Carlo calculation for pebble bed reactors

    International Nuclear Information System (INIS)

    Murata, Isao; Takahashi, Akito; Mori, Takamasa; Nakagawa, Masayuki.

    1997-01-01

    A pebble bed reactor generally has double heterogeneity consisting of two kinds of spherical fuel element. In the core, there exist many fuel balls piled up randomly in a high packing fraction. And each fuel ball contains a lot of small fuel particles which are also distributed randomly. In this study, to realize precise neutron transport calculation of such reactors with the continuous energy Monte Carlo method, a new sampling method has been developed. The new method has been implemented in the general purpose Monte Carlo code MCNP to develop a modified version MCNP-BALL. This method was validated by calculating inventory of spherical fuel elements arranged successively by sampling during transport calculation and also by performing criticality calculations in ordered packing models. From the results, it was confirmed that the inventory of spherical fuel elements could be reproduced using MCNP-BALL within a sufficient accuracy of 0.2%. And the comparison of criticality calculations in ordered packing models between MCNP-BALL and the reference method shows excellent agreement in neutron spectrum as well as multiplication factor. MCNP-BALL enables us to analyze pebble bed type cores such as PROTEUS precisely with the continuous energy Monte Carlo method. (author)

  14. The continuous fuel cycle model and the gas cooled fast reactor

    International Nuclear Information System (INIS)

    Christie, Stuart; Lathouwers, Danny; Kloosterman, Jan Leen; Hagen, Tim van der

    2011-01-01

    The gas cooled fast reactor (GFR) is one of the generation IV designs currently being evaluated for future use. It is intended to behave as an isobreeder, producing the same amount of fuel as it consumes during operation. The actinides in the fuel will be recycled repeatedly in order to minimise the waste output to fission products only. Striking the balance of the fissioning of various actinides against transmutation and decay to achieve these goals is a complex problem. This is compounded by the time required for burn-up modelling, which can be considerable for a single cycle, and even longer for studies of fuel evolution over many cycles. The continuous fuel cycle model approximates the discrete steps of loading, operating and unloading a reactor as continuous processes. This simplifies the calculations involved in simulating the behaviour of the fuel, reducing the time needed to model the changes to the fuel composition over many cycles. This method is used to study the behaviour of GFR fuel over many cycles and compared to results obtained from direct calculations. The effects of varying fuel cycle properties such as feed material, recycling of additional actinides and reprocessing losses are also investigated. (author)

  15. Removal of triazine herbicides from aqueous systems by a biofilm reactor continuously or intermittently operated.

    Science.gov (United States)

    Sánchez-Sánchez, R; Ahuatzi-Chacón, D; Galíndez-Mayer, J; Ruiz-Ordaz, N; Salmerón-Alcocer, A

    2013-10-15

    The impact of pesticide movement via overland flow or tile drainage water on the quality of receiving water bodies has been a serious concern in the last decades; thus, for remediation of water contaminated with herbicides, bioreaction systems designed to retain biomass have been proposed. In this context, the aim of this study was to evaluate the atrazine and terbutryn biodegradation capacity of a microbial consortium, immobilized in a biofilm reactor (PBR), packed with fragments of porous volcanic stone. The microbial consortium, constituted by four predominant bacterial strains, was used to degrade a commercial formulation of atrazine and terbutryn in the biofilm reactor, intermittently or continuously operated at volumetric loading rates ranging from 44 to 306 mg L(-1) d(-1). The complete removal of both herbicides was achieved in both systems; however, higher volumetric removal rates were obtained in the continuous system. It was demonstrated that the adjuvants of the commercial formulation of the herbicide significantly enhanced the removal of atrazine and terbutryn. Copyright © 2013 Elsevier Ltd. All rights reserved.

  16. Bioremoval of trivalent chromium using Bacillus biofilms through continuous flow reactor

    Energy Technology Data Exchange (ETDEWEB)

    Sundar, K.; Sadiq, I. Mohammed; Mukherjee, Amitava [Centre for Nanobiotechnology, Nano Bio-Medicine Laboratory School of Bio Sciences and Technology VIT University, Vellore - 632014 (India); Chandrasekaran, N., E-mail: nchandrasekaran@vit.ac.in [Centre for Nanobiotechnology, Nano Bio-Medicine Laboratory School of Bio Sciences and Technology VIT University, Vellore - 632014 (India)

    2011-11-30

    Highlights: Black-Right-Pointing-Pointer Effective bioremoval of Cr(III) using bacterial biofilms. Black-Right-Pointing-Pointer Simplified bioreactor was fabricated for the biofilm development and Cr(III) removal. Black-Right-Pointing-Pointer Economically feasible substrate like coarse sand and pebbles were used. - Abstract: Present study deals with the applicability of bacterial biofilms for the bioremoval of trivalent chromium from tannery effluents. A continuous flow reactor was designed for the development of biofilms on different substrates like glass beads, pebbles and coarse sand. The parameters for the continuous flow reactor were 20 ml/min flow rate at 30 Degree-Sign C, pH4. Biofilm biomass on the substrates was in the following sequence: coarse sand > pebbles > glass beads (4.8 Multiplication-Sign 10{sup 7}, 4.5 Multiplication-Sign 10{sup 7} and 3.5 Multiplication-Sign 10{sup 5} CFU/cm{sup 2}), which was confirmed by CLSM. Biofilms developed using consortium of Bacillus subtilis and Bacillus cereus on coarse sand had more surface area and was able to remove 98% of Cr(III), SEM-EDX proved 92.60% Cr(III) adsorption on biofilms supported by coarse sand. Utilization of Bacillus biofilms for effective bioremoval of Cr(III) from chrome tanning effluent could be a better option for tannery industry, especially during post chrome tanning operation.

  17. Measurements of liquid phase residence time distributions in a pilot-scale continuous leaching reactor using radiotracer technique

    International Nuclear Information System (INIS)

    Pant, H.J.; Sharma, V.K.; Shenoy, K.T.; Sreenivas, T.

    2015-01-01

    An alkaline based continuous leaching process is commonly used for extraction of uranium from uranium ore. The reactor in which the leaching process is carried out is called a continuous leaching reactor (CLR) and is expected to behave as a continuously stirred tank reactor (CSTR) for the liquid phase. A pilot-scale CLR used in a Technology Demonstration Pilot Plant (TDPP) was designed, installed and operated; and thus needed to be tested for its hydrodynamic behavior. A radiotracer investigation was carried out in the CLR for measurement of residence time distribution (RTD) of liquid phase with specific objectives to characterize the flow behavior of the reactor and validate its design. Bromine-82 as ammonium bromide was used as a radiotracer and about 40–60 MBq activity was used in each run. The measured RTD curves were treated and mean residence times were determined and simulated using a tanks-in-series model. The result of simulation indicated no flow abnormality and the reactor behaved as an ideal CSTR for the range of the operating conditions used in the investigation. - Highlights: • Radiotracer technique was applied for evaluation of design of a pilot-scale continuous leaching reactor. • Mean residence time and dead volume were estimated. Dead volume was found to be ranging from 4% to 15% at different operating conditions. • Tank-in-series model was used to simulate the measured RTD data and was found suitable to describe the flow in the reactor. • No flow abnormality was found and the reactor behaved as a well-mixed system. The design of the reactor was validated

  18. Membrane reactor for water detritiation: a parametric study on operating parameters

    Energy Technology Data Exchange (ETDEWEB)

    Mascarade, J.; Liger, K.; Troulay, M.; Perrais, C. [CEA, DEN, DTN/STPA/LIPC, Centre de Cadarache, Saint-Paul-lez-Durance (France); Joulia, X.; Meyer, X.M. [Universite de Toulouse, INPT, UPS, Laboratoire de Genie Chimique, Toulouse (France); CNRS, Laboratoire de Genie Chimique, Toulouse (France)

    2015-03-15

    This paper presents the results of a parametric study done on a single stage finger-type packed-bed membrane reactor (PBMR) used for heavy water vapor de-deuteration. Parametric studies have been done on 3 operating parameters which are: the membrane temperature, the total feed flow rate and the feed composition through D{sub 2}O content variations. Thanks to mass spectrometer analysis of streams leaving the PBMR, speciation of deuterated species was achieved. Measurement of the amounts of each molecular component allowed the calculation of reaction quotient at the packed-bed outlet. While temperature variation mainly influences permeation efficiency, feed flow rate perturbation reveals dependence of conversion and permeation properties to contact time between catalyst and reacting mixture. The study shows that isotopic exchange reactions occurring on the catalyst particles surface are not thermodynamically balanced. Moreover, the variation of the heavy water content in the feed exhibits competition between permeation and conversion kinetics.

  19. Development of an emergency air-cleaning system for liquid-metal reactors

    International Nuclear Information System (INIS)

    Owen, R.K.

    1980-11-01

    A novel air cleaning concept has been developed for potential use in venting future commercial liquid metal fast breeder reactor containment buildings in the unlikely event of postulated core disruptive accidents. The passive concept consists of a submerged gravel bed to collect the bulk of particulate contaminates carried by the vented gas. A fibrous scrubber could be combined with the submerged gravel scrubber to enhance collection efficiencies for the smaller sized particles. The submerged gravel scrubber is unique in that water flow through the packed bed is induced by the gas flow, eliminating the need for an active liquid pump. In addition, design gas velocities through the packed bed are 10 to 20 times higher than for a conventional sand bed filter

  20. Performance of continuous stirred tank reactor (CSTR) on fermentative biohydrogen production from melon waste

    Science.gov (United States)

    Cahyari, K.; Sarto; Syamsiah, S.; Prasetya, A.

    2016-11-01

    This research was meant to investigate performance of continuous stirred tank reactor (CSTR) as bioreactor for producing biohydrogen from melon waste through dark fermentation method. Melon waste are commonly generated from agricultural processing stages i.e. cultivation, post-harvesting, industrial processing, and transportation. It accounted for more than 50% of total harvested fruit. Feedstock of melon waste was fed regularly to CSTR according to organic loading rate at value 1.2 - 3.6 g VS/ (l.d). Optimum condition was achieved at OLR 2.4 g VS/ (l.d) with the highest total gas volume 196 ml STP. Implication of higher OLR value is reduction of total gas volume due to accumulation of acids (pH 4.0), and lower substrate volatile solid removal. In summary, application of this method might valorize melon waste and generates renewable energy sources.

  1. Biohydrogen production from waste bread in a continuous stirred tank reactor: A techno-economic analysis.

    Science.gov (United States)

    Han, Wei; Hu, Yun Yi; Li, Shi Yi; Li, Fei Fei; Tang, Jun Hong

    2016-12-01

    Biohydrogen production from waste bread in a continuous stirred tank reactor (CSTR) was techno-economically assessed. The treating capacity of the H 2 -producing plant was assumed to be 2 ton waste bread per day with lifetime of 10years. Aspen Plus was used to simulate the mass and energy balance of the plant. The total capital investment (TCI), total annual production cost (TAPC) and annual revenue of the plant were USD931020, USD299746/year and USD639920/year, respectively. The unit hydrogen production cost was USD1.34/m 3 H 2 (or USD14.89/kg H 2 ). The payback period and net present value (NPV) of the plant were 4.8years and USD1266654, respectively. Hydrogen price and operators cost were the most important variables on the NPV. It was concluded that biohydrogen production from waste bread in the CSTR was feasible for practical application. Copyright © 2016 Elsevier Ltd. All rights reserved.

  2. Treatment of landfill leachate by Fenton's reagent in a continuous stirred tank reactor

    International Nuclear Information System (INIS)

    Zhang Hui; Choi, H.J.; Huang, C.-P.

    2006-01-01

    The treatment of landfill leachate by Fenton process was carried out in a continuous stirred tank reactor (CSTR). The effect of operating conditions such as reaction time, hydraulic retention time, pH, H 2 O 2 to Fe(II) molar ratio, Fenton's reagent dosage, initial COD strength, and temperature on the efficacy of Fenton process was investigated. It is demonstrated that Fenton's reagent can effectively degrade leachate organics. Fenton process reached the steady state after three times of hydraulic retention. The oxidation of organic materials in the leachate was pH dependent and the optimal pH was 2.5. The favorable H 2 O 2 to Fe(II) molar ratio was 3, and organic removal increased as dosage increased at the favorable H 2 O 2 to Fe(II) molar ratio. Temperature gave a positive effect on organic removal

  3. Demonstration of the waste tire pyrolysis process on pilot scale in a continuous auger reactor

    International Nuclear Information System (INIS)

    Martínez, Juan Daniel; Murillo, Ramón; García, Tomás; Veses, Alberto

    2013-01-01

    Highlights: • The continuous pyrolysis of waste tire has been demonstrated at pilot scale in an auger reactor. • More than 500 kg of waste tires were processed in 100 operational hours. • The yields and characteristics of the pyrolysis products remained constant. • Mass and energy balances for an industrial scale plant are provided. • The reaction enthalpy necessary to perform the waste tire pyrolysis was determined. -- Abstract: This work shows the technical feasibility for valorizing waste tires by pyrolysis using a pilot scale facility with a nominal capacity of 150 kW th . A continuous auger reactor was operated to perform thirteen independent experiments that conducted to the processing of more than 500 kg of shredded waste tires in 100 h of operation. The reaction temperature was 550 °C and the pressure was 1 bar in all the runs. Under these conditions, yields to solid, liquid and gas were 40.5 ± 0.3, 42.6 ± 0.1 and 16.9 ± 0.3 wt.% respectively. Ultimate and proximate analyses as well as heating value analysis were conducted for both the solid and liquid fraction. pH, water content, total acid number (TAN), viscosity and density were also assessed for the liquid and compared to the specifications of marine fuels (standard ISO 8217). Gas chromatography was used to calculate the composition of the gaseous fraction. It was observed that all these properties remained practically invariable along the experiments without any significant technical problem. In addition, the reaction enthalpy necessary to perform the waste tire pyrolysis process (907.1 ± 40.0 kJ/kg) was determined from the combustion and formation enthalpies of waste tire and conversion products. Finally, a mass balance closure was performed showing an excellent reliability of the data obtained from the experimental campaign

  4. Demonstration of the waste tire pyrolysis process on pilot scale in a continuous auger reactor

    Energy Technology Data Exchange (ETDEWEB)

    Martínez, Juan Daniel, E-mail: juand.martinez@upb.edu.co [Instituto de Carboquímica, ICB-CSIC, Miguel Luesma Castán 4, 50018, Zaragoza (Spain); Grupo de Investigaciones Ambientales, Instituto de Energía, Materiales y Medio Ambiente, Universidad Pontificia Bolivariana, Circular 1 N°70-01, Bloque 11, piso 2, Medellín (Colombia); Murillo, Ramón; García, Tomás; Veses, Alberto [Instituto de Carboquímica, ICB-CSIC, Miguel Luesma Castán 4, 50018, Zaragoza (Spain)

    2013-10-15

    Highlights: • The continuous pyrolysis of waste tire has been demonstrated at pilot scale in an auger reactor. • More than 500 kg of waste tires were processed in 100 operational hours. • The yields and characteristics of the pyrolysis products remained constant. • Mass and energy balances for an industrial scale plant are provided. • The reaction enthalpy necessary to perform the waste tire pyrolysis was determined. -- Abstract: This work shows the technical feasibility for valorizing waste tires by pyrolysis using a pilot scale facility with a nominal capacity of 150 kW{sub th}. A continuous auger reactor was operated to perform thirteen independent experiments that conducted to the processing of more than 500 kg of shredded waste tires in 100 h of operation. The reaction temperature was 550 °C and the pressure was 1 bar in all the runs. Under these conditions, yields to solid, liquid and gas were 40.5 ± 0.3, 42.6 ± 0.1 and 16.9 ± 0.3 wt.% respectively. Ultimate and proximate analyses as well as heating value analysis were conducted for both the solid and liquid fraction. pH, water content, total acid number (TAN), viscosity and density were also assessed for the liquid and compared to the specifications of marine fuels (standard ISO 8217). Gas chromatography was used to calculate the composition of the gaseous fraction. It was observed that all these properties remained practically invariable along the experiments without any significant technical problem. In addition, the reaction enthalpy necessary to perform the waste tire pyrolysis process (907.1 ± 40.0 kJ/kg) was determined from the combustion and formation enthalpies of waste tire and conversion products. Finally, a mass balance closure was performed showing an excellent reliability of the data obtained from the experimental campaign.

  5. Synthetic olive mill wastewater treatment by Fenton's process in batch and continuous reactors operation.

    Science.gov (United States)

    Esteves, Bruno M; Rodrigues, Carmen S D; Madeira, Luís M

    2017-11-04

    Degradation of total phenol (TPh) and organic matter, (expressed as total organic carbon TOC), of a simulated olive mill wastewater was evaluated by the Fenton oxidation process under batch and continuous mode conditions. A mixture of six phenolic acids usually found in these agro-industrial wastewaters was used for this purpose. The study focused on the optimization of key operational parameters of the Fenton process in a batch reactor, namely Fe 2+ dosage, hydrogen peroxide concentration, pH, and reaction temperature. On the assessment of the process efficiency, > 99% of TPh and > 56% of TOC removal were attained when [Fe 2+ ] = 100 ppm, [H 2 O 2 ] = 2.0 g/L, T = 30 °C, and initial pH = 5.0, after 300 min of reaction. Under those operational conditions, experiments on a continuous stirred-tank reactor (CSTR) were performed for different space-time values (τ). TOC and TPh removals of 47.5 and 96.9%, respectively, were reached at steady-state (for τ = 120 min). High removal of COD (> 75%) and BOD 5 (> 70%) was achieved for both batch and CSTR optimum conditions; analysis of the BOD 5 /COD ratio also revealed an increase in the effluent's biodegradability. Despite the high removal of lumped parameters, the treated effluent did not met the Portuguese legal limits for direct discharge of wastewaters into water bodies, which indicates that coupled chemical-biological process may be the best solution for real olive mill wastewater treatment.

  6. Titer plate formatted continuous flow thermal reactors for high throughput applications: fabrication and testing

    International Nuclear Information System (INIS)

    Park, Daniel Sang-Won; Chen, Pin-Chuan; You, Byoung Hee; Kim, Namwon; Park, Taehyun; Lee, Tae Yoon; Soper, Steven A; Nikitopoulos, Dimitris E; Murphy, Michael C; Datta, Proyag; Desta, Yohannes

    2010-01-01

    A high throughput, multi-well (96) polymerase chain reaction (PCR) platform, based on a continuous flow (CF) mode of operation, was developed. Each CFPCR device was confined to a footprint of 8 × 8 mm 2 , matching the footprint of a well on a standard micro-titer plate. While several CFPCR devices have been demonstrated, this is the first example of a high-throughput multi-well continuous flow thermal reactor configuration. Verification of the feasibility of the multi-well CFPCR device was carried out at each stage of development from manufacturing to demonstrating sample amplification. The multi-well CFPCR devices were fabricated by micro-replication in polymers, polycarbonate to accommodate the peak temperatures during thermal cycling in this case, using double-sided hot embossing. One side of the substrate contained the thermal reactors and the opposite side was patterned with structures to enhance thermal isolation of the closely packed constant temperature zones. A 99 bp target from a λ-DNA template was successfully amplified in a prototype multi-well CFPCR device with a total reaction time as low as ∼5 min at a flow velocity of 3 mm s −1 (15.3 s cycle −1 ) and a relatively low amplification efficiency compared to a bench-top thermal cycler for a 20-cycle device; reducing the flow velocity to 1 mm s −1 (46.2 s cycle −1 ) gave a seven-fold improvement in amplification efficiency. Amplification efficiencies increased at all flow velocities for 25-cycle devices with the same configuration.

  7. Hydrothermal gasification of glucose and starch in a batch and continuous reactor

    Directory of Open Access Journals (Sweden)

    Kazuhiro Kumabe

    2017-11-01

    Full Text Available A batch reactor was used for the gasification of glucose and starch as carbohydrate model compounds. The effects of H2O in various states (low-pressure hot compressed water (LP-HCW, 300 °C and 10 MPa, high-pressure hot compressed water (HP-HCW, 360 °C and 20 MPa, high-temperature steam (HTS, 400 °C and 10 MPa, and supercritical water (SCW, 400 °C and 25 MPa, as well as reaction time (10, 30, and 60 min, sample concentration (10, 20, and 30 wt%, and catalyst (mixture of Ca(OH2 and Na2CO3 on gas production were investigated in the hydrothermal gasification. In addition, using a continuous reactor, the hydrothermal gasification of glucose was examined with LP-HCW (200 °C and 5 MPa, HP-HCW (200 °C and 25 MPa, HTS (600 °C, 5 MPa, and SCW (600 °C, 25 MPa in order to study the productions of gases and tar, and the mass balance. The reaction temperature affected gasification considerably, but pressure had little effect. In the batch experiments, the characteristics of the produced gases were almost identical after a reaction time of 10 min, and addition of Ca(OH2 and Na2CO3 as catalysts in a molar ratio of 7:3 led to selective production of H2 in the SCW gasification of 10 wt% glucose for 30 min. In a continuous experiment under the SCW conditions, the conversion efficiency of glucose to gas was 26% and the composition of the produced gas was 29 vol% CO, 23 vol% H2, and 16 vol% CH4. Under the hydrothermal conditions, glucose was mainly converted to char and suspended components of high-molecular-weight compounds such as fat, whereas starch was mainly converted to gas and liquid.

  8. Limits and conditions for continuous operation of WWR-S reactor

    International Nuclear Information System (INIS)

    Pittermann, P.; Listik, E.

    1979-02-01

    The fundamental technological and nuclear characteristics of the WWR-S reactor, safety limits and concepts of technical surveillance with particular attention to radiation safety of staff and of neighbouring population are outlined. The rules are mandatory for the reactor staff and for the users. The material is part of safety documentation for the WWR-S reactor. (author)

  9. Production of hydrogen in a granular sludge-based anaerobic continuous stirred tank reactor

    Energy Technology Data Exchange (ETDEWEB)

    Show, Kuan-Yeow [Faculty of Engineering and Science, University of Tunku Abdul Rahman, 53300 Setapak, Kuala Lumpur (Malaysia); Zhang, Zhen-Peng; Tay, Joo-Hwa [School of Civil and Environmental Engineering, Nanyang Technological University, 639798 (Singapore); Institute of Environmental Science and Engineering, Nanyang Technological University, 637723 (Singapore); Tee Liang, David [Institute of Environmental Science and Engineering, Nanyang Technological University, 637723 (Singapore); Lee, Duu-Jong [Department of Chemical Engineering, National Taiwan University, Taipei 10617, Taiwan, RO (China); Jiang, Wen-Ju [Department of Environmental Science and Engineering, Sichuan University, Chengdu 610065 (China)

    2007-12-15

    An investigation on biohydrogen production was conducted in a granular sludge-based continuous stirred tank reactor (CSTR). The reactor performance was assessed at five different glucose concentrations of 2.5, 5, 10, 20 and 40 g/L and four hydraulic retention times (HRTs) of 0.25, 0.5, 1 and 2 h, resulting in the organic loading rates (OLRs) ranged between 2.5 and 20 g-glucose/L h. Carbon flow was traced by analyzing the composition of gaseous and soluble metabolites as well as the cell yield. Butyrate, acetate and ethanol were found to be the major soluble metabolite products in the biochemical synthesis of hydrogen. Carbon balance analysis showed that more than half of the glucose carbon was converted into unidentified soluble products at an OLR of 2.5 g-glucose/L h. It was found that high hydrogen yields corresponded to a sludge loading rate in between 0.6 and 0.8 g-glucose/g-VSS h. Substantial suppression in hydrogen yield was noted as the sludge loading rate fell beyond the optimum range. It is deduced that decreasing the sludge loading rate induced the metabolic shift of biochemical reactions at an OLR of 2.5 g-glucose/L h, which resulted in a substantial reduction in hydrogen yield to 0.36-0.41 mol-H{sub 2}/mol-glucose. Optimal operation conditions for peak hydrogen yield (1.84 mol-H{sub 2}/mol-glucose) and hydrogen production rate (3.26 L/L h) were achieved at an OLR of 20 g-glucose/L h, which corresponded to an HRT of 0.5 h and an influent glucose concentration of 10 g/L. Influence of HRT and substrate concentration on the reactor performance was interrelated and the adverse impact on hydrogen production was noted as substrate concentration was higher than 20 g/L or HRT was shorter than 0.5 h. The experimental study indicated that a higher OLR derived from appropriate HRTs and substrate concentrations was desirable for hydrogen production in such a granule-based CSTR. (author)

  10. Continuous and rapid synthesis of nanoclusters and nanocrystals using scalable microstructured reactors

    Science.gov (United States)

    Jin, Hyung Dae

    Recent advances in nanocrystalline materials production are expected to impact the development of next generation low-cost and/or high efficiency solar cells. For example, semiconductor nanocrystal inks are used to lower the fabrication cost of the absorber layers of the solar cells. In addition, some quantum confined nanocrystals display electron-hole pair generation phenomena with greater than 100% quantum yield, called multiple exciton generation (MEG). These quantum dots could potentially be used to fabricate solar cells that exceed the Schockley-Queisser limit. At present, continuous syntheses of nanoparticles using microreactors have been reported by several groups. Microreactors have several advantages over conventional batch synthesis. One advantage is their efficient heat transfer and mass transport. Another advantage is the drastic reduction in the reaction time, in many cases, down to minutes from hours. Shorter reaction time not only provides higher throughput but also provide better particle size control by avoiding aggregation and by reducing probability of oxidizing precursors. In this work, room temperature synthesis of Au11 nanoclusters and high temperature synthesis of chalcogenide nanocrystals were demonstrated using continuous flow microreactors with high throughputs. A high rate production of phosphine-stabilized Au11 nanoclusters was achieved using a layer-up strategy which involves the use of microlamination architectures; the patterning and bonding of thin layers of material (laminae) to create a multilayered micromixer in the range of 25-250 mum thick was used to step up the production of phosphine-stabilized Au11 nanoclusters. Continuous production of highly monodispersed phosphine-stabilized Au 11 nanoclusters at a rate of about 11.8 [mg/s] was achieved using a microreactor with a size of 1.687cm3. This result is about 30,000 times over conventional batch synthesis according to production rate/per reactor volume. We have elucidated the

  11. Measurements of liquid phase residence time distributions in a pilot-scale continuous leaching reactor using radiotracer technique.

    Science.gov (United States)

    Pant, H J; Sharma, V K; Shenoy, K T; Sreenivas, T

    2015-03-01

    An alkaline based continuous leaching process is commonly used for extraction of uranium from uranium ore. The reactor in which the leaching process is carried out is called a continuous leaching reactor (CLR) and is expected to behave as a continuously stirred tank reactor (CSTR) for the liquid phase. A pilot-scale CLR used in a Technology Demonstration Pilot Plant (TDPP) was designed, installed and operated; and thus needed to be tested for its hydrodynamic behavior. A radiotracer investigation was carried out in the CLR for measurement of residence time distribution (RTD) of liquid phase with specific objectives to characterize the flow behavior of the reactor and validate its design. Bromine-82 as ammonium bromide was used as a radiotracer and about 40-60MBq activity was used in each run. The measured RTD curves were treated and mean residence times were determined and simulated using a tanks-in-series model. The result of simulation indicated no flow abnormality and the reactor behaved as an ideal CSTR for the range of the operating conditions used in the investigation. Copyright © 2014 Elsevier Ltd. All rights reserved.

  12. Characteristics of biohydrogen production by ethanoligenens R{sub 3} isolated from continuous stirred tank reactor

    Energy Technology Data Exchange (ETDEWEB)

    Jiao, A.Y.; Liu, K. [Northeast Forestry Univ., Harbin (China). School of Forestry; Li, Y.F. [Northeast Forestry Univ., Harbin (China). School of Forestry; Shanghai Univ. of Engineering Science (China). College of Chemistry and Chemical Engineering; Liu, B. [Northeast Forestry Univ., Harbin (China). School of Material Science and Engineering; Xu, J.L. [Shanghai Univ. of Engineering Science (China). College of Chemistry and Chemical Engineering

    2010-07-01

    This study investigated the fermentative hydrogen production characteristics of ethanoligenens R{sub 3} isolated from anaerobic sludge in a continuous stirred tank reactor. The effects of the initial pH value, the proportion of carbon and nitrogen sources, and the effects of fermentation temperature were investigated in a series of batch experiments. Substrates for the hydrogen production of glucose and peptone were used as carbon and nitrogen sources. Results of the experiments showed that a maximum hydrogen production yield of 834 mlH{sub 2}/L culture was obtained with a fermentation temperature of 35 degrees C and an initial pH value of 5.5. The maximum average hydrogen production rate of 10.87 mmolH{sub 2}/g cell dry weight per hour was obtained at a carbon-nitrogen source ratio of 3.3. The degradation efficiency of the glucose used as a carbon source ranged from 91.5 to 95.43 per cent during the conversion of glucose to hydrogen by the bacteria.

  13. Demonstration of the waste tire pyrolysis process on pilot scale in a continuous auger reactor.

    Science.gov (United States)

    Martínez, Juan Daniel; Murillo, Ramón; García, Tomás; Veses, Alberto

    2013-10-15

    This work shows the technical feasibility for valorizing waste tires by pyrolysis using a pilot scale facility with a nominal capacity of 150 kWth. A continuous auger reactor was operated to perform thirteen independent experiments that conducted to the processing of more than 500 kg of shredded waste tires in 100 h of operation. The reaction temperature was 550°C and the pressure was 1 bar in all the runs. Under these conditions, yields to solid, liquid and gas were 40.5 ± 0.3, 42.6 ± 0.1 and 16.9 ± 0.3 wt.% respectively. Ultimate and proximate analyses as well as heating value analysis were conducted for both the solid and liquid fraction. pH, water content, total acid number (TAN), viscosity and density were also assessed for the liquid and compared to the specifications of marine fuels (standard ISO 8217). Gas chromatography was used to calculate the composition of the gaseous fraction. It was observed that all these properties remained practically invariable along the experiments without any significant technical problem. In addition, the reaction enthalpy necessary to perform the waste tire pyrolysis process (907.1 ± 40.0 kJ/kg) was determined from the combustion and formation enthalpies of waste tire and conversion products. Finally, a mass balance closure was performed showing an excellent reliability of the data obtained from the experimental campaign. Copyright © 2013 Elsevier B.V. All rights reserved.

  14. Arsenic and fluoride removal from groundwater by electrocoagulation using a continuous filter-press reactor.

    Science.gov (United States)

    Guzmán, Athziri; Nava, José L; Coreño, Oscar; Rodríguez, Israel; Gutiérrez, Silvia

    2016-02-01

    We investigated simultaneous arsenic and fluoride removal from ground water by electrocoagulation (EC) using aluminum as the sacrificial anode in a continuous filter-press reactor. The groundwater was collected at a depth of 320 m in the Bajío region in Guanajuato Mexico (arsenic 43 µg L(-1), fluoride 2.5 mg L(-1), sulfate 89.6 mg L(-1), phosphate 1.8 mg L(-1), hydrated silica 112.4 mg L(-1), hardness 9.8 mg L(-1), alkalinity 31.3 mg L(-1), pH 7.6 and conductivity 993 µS cm(-1)). EC was performed after arsenite was oxidized to arsenate by addition of 1 mg L(-1) hypochlorite. The EC tests revealed that at current densities of 4, 5 and 6 mA cm(-2) and flow velocities of 0.91 and 1.82 cm s(-1), arsenate was abated and residual fluoride concentration satisfies the WHO standard (CF < 1.5 mg L(-1)). Spectrometric analyses performed on aluminum flocs indicated that these are mainly composed of aluminum-silicates of calcium and magnesium. Arsenate removal by EC involves adsorption on aluminum flocs, while fluoride replaces a hydroxyl group from aluminum aggregates. The best EC was obtained at 4 mA cm(-2) and 1.82 cm s(-1) with electrolytic energy consumption of 0.34 KWh m(-3). Copyright © 2015 Elsevier Ltd. All rights reserved.

  15. Investigation of furfural biodegradation in a continuous inflow cyclic biological reactor.

    Science.gov (United States)

    Moussavi, Gholamreza; Leili, Mostafa; Nadafi, Kazem

    2016-01-01

    The performance of a continuous inflow cyclic biological reactor (CBR) containing moving media was investigated for the degradation of high concentrations of furfural. The effects of hydraulic retention time (HRT) and furfural initial concentrations (loading rate), as main operating parameters, on the bioreactor performance were studied. The results indicated that the CBR could remove over 98% of furfural and 71% of its chemical oxygen demand (COD) at inlet furfural concentrations up to 1,200 mg L(-1) (2.38 g L(-1) d(-1)), a 6-h cycle time and HRT of 12.1 h. The removal efficiency decreased slightly from 98 to 94% when HRT decreased from 12.1 to 10.5 h. The average removal efficiency of furfural and COD during the 345-day operational period under steady-state conditions were 97.7% and 82.1%, respectively. The efficiency also increased approximately 17.2% after addition of synthetic polyurethane cubes as moving media at a filling ratio of 10%.

  16. Continuous xylanase production with Aspergillus nidulans under pyridoxine limitation using a trickle bed reactor.

    Science.gov (United States)

    Müller, Michael; Prade, Rolf A; Segato, Fernando; Atiyeh, Hasan K; Wilkins, Mark R

    2015-01-01

    A trickle bed reactor (TBR) with recycle was designed and tested using Aspergillus nidulans with a pyridoxine marker and over-expressing/secreting recombinant client xylanase B (XynB). The pyridoxine marker prevented the fungus from synthesizing its own pyridoxine and fungus was unable to grow when no pyridoxine was present in the medium; however, enzyme production was unaffected. Uncontrolled mycelia growth that led to clogging of the TBR was observed when fungus without a pyridoxine marker was used for XynB production. Using the fungus with pyridoxine marker, the TBR was operated continuously for 18 days and achieved a XynB output of 41 U/ml with an influent and effluent flow rate of 0.5 ml/min and a recycle flow rate of 56 ml/min. Production yields in the TBR were 1.4 times greater than a static tray culture and between 1.1 and 67 times greater than yields for SSF enzyme production stated in the literature. Copyright © 2015 Elsevier Ltd. All rights reserved.

  17. Continuous aryl alcohol oxidase production under growth-limited conditions using a trickle bed reactor.

    Science.gov (United States)

    Pardo-Planas, Oscar; Atiyeh, Hasan K; Prade, Rolf A; Müller, Michael; Wilkins, Mark R

    2018-05-01

    An A. nidulans strain with a pyridoxine marker was used for continuous production of aryl alcohol oxidase (AAO) in a trickle bed reactor (TBR). Modified medium with reduced zinc, no copper, and 5 g/L ascorbic acid that reduced melanin production and increased AAO productivity under growth limited conditions was used. Two air flow rates, 0.11 L/min (0.1 vvm) and 1.1 L/min (1.0 vvm) were tested. More melanin formation and reduced protein productivity were observed with air flow rate of 1.1 L/min. Three random packings were used as support for the fungus inside the TBR column, two of which were hydrophobic and one which was hydrophilic, and three different dilution rates were tested. The use of GEA BCN 030 hydrophobic packing resulted in greater AAO yield and productivity than the other packings. Increasing dilution rates favored melanin formation and citric, lactic and succinic acid accumulation, which decreased AAO yield and productivity. Copyright © 2018 Elsevier Ltd. All rights reserved.

  18. Removal of phosphorus from aqueous solution by Posidonia oceanica fibers using continuous stirring tank reactor

    Energy Technology Data Exchange (ETDEWEB)

    Wahab, Mohamed Ali, E-mail: waheb_med@yahoo.fr [University of Carthage, Water Research and Technologies Centre (CERTE), Wastewater Treatment and Recycling Laboratory, B.P. 273, 8020 Soliman (Tunisia); Hassine, Rafik Ben [International Environmental Green Technology (IGET) (Tunisia); Jellali, Salah, E-mail: salah.jallali@certe.rnrt.tn [University of Carthage, Water Research and Technologies Centre (CERTE), Wastewater Treatment and Recycling Laboratory, B.P. 273, 8020 Soliman (Tunisia)

    2011-05-15

    The present study aims to develop a new potentially low-cost, sustainable treatment approach to soluble inorganic phosphorus removal from synthetic solutions and secondary wastewater effluents in which a plant waste (Posidonia oceanica fiber: POF) is used for further agronomic benefit. Dynamic flow tests using a continuous stirred tank reactor (CSTR) were carried out to study the effect of initial concentration of phosphorus, amount of adsorbent, feeding flow rate and anions competition. The experimental results showed that the removal efficiency of phosphorus from synthetic solutions is about 80% for 10 g L{sup -1} of POF. In addition, the variation of the initial concentration of phosphorus from 8 to 50 mg L{sup -1} increased the adsorption capacity from 0.99 to 3.03 mg g{sup -1}. The use of secondary treated wastewater showed the presence of competition phenomenon between phosphorus and sulphate which could be overcoming with increasing the sorptive surface area and providing more adsorption sites when increasing the adsorbent dosage of POF. Compared with columns studies, this novel CSTR system showed more advantages for the removal of soluble phosphorus as a tertiary treatment of urban secondary effluents with more adsorption efficiency and capacity, in addition to the prospect use of saturated POF with nutriment as fertilizer and compost.

  19. Removal of phosphorus from aqueous solution by Posidonia oceanica fibers using continuous stirring tank reactor

    International Nuclear Information System (INIS)

    Wahab, Mohamed Ali; Hassine, Rafik Ben; Jellali, Salah

    2011-01-01

    The present study aims to develop a new potentially low-cost, sustainable treatment approach to soluble inorganic phosphorus removal from synthetic solutions and secondary wastewater effluents in which a plant waste (Posidonia oceanica fiber: POF) is used for further agronomic benefit. Dynamic flow tests using a continuous stirred tank reactor (CSTR) were carried out to study the effect of initial concentration of phosphorus, amount of adsorbent, feeding flow rate and anions competition. The experimental results showed that the removal efficiency of phosphorus from synthetic solutions is about 80% for 10 g L -1 of POF. In addition, the variation of the initial concentration of phosphorus from 8 to 50 mg L -1 increased the adsorption capacity from 0.99 to 3.03 mg g -1 . The use of secondary treated wastewater showed the presence of competition phenomenon between phosphorus and sulphate which could be overcoming with increasing the sorptive surface area and providing more adsorption sites when increasing the adsorbent dosage of POF. Compared with columns studies, this novel CSTR system showed more advantages for the removal of soluble phosphorus as a tertiary treatment of urban secondary effluents with more adsorption efficiency and capacity, in addition to the prospect use of saturated POF with nutriment as fertilizer and compost.

  20. High pressure hydropyrolysis of coals by using a continuous free-fall reactor

    Energy Technology Data Exchange (ETDEWEB)

    W.-C. Xu; K. Matsuoka; H. Akiho; M. Kumagai; A. Tomita [Institute of Research and Innovation, Kashiwa (Japan)

    2003-04-01

    Rapid hydropyrolysis of coal was carried out at temperatures ranging from 923 to 1123 K and H{sub 2} pressures up to 7 MPa by using a continuous free-fall pyrolyzer. The effects of the reaction conditions on product yields were investigated. Carbon mass balance was fairly good. It was revealed that a large amount of methane was produced due to the hydrogenolysis of higher hydrocarbons and the hydrogasification of char. The influence of pyrolysis temperature was significant on both reactions while H{sub 2} pressure mainly affected the latter. A considerable amount of reactive carbon was formed during hydropyrolysis of coal. It was converted to methane at high temperatures and high H{sub 2} pressures, while the hydrogasification of reactive carbon takes place relatively slowly at low temperatures and low H{sub 2} pressures, resulting in a low overall carbon conversion. The coal conversions observed in the present study were much higher than those obtained with using reactors where the contact between coal particles and H{sub 2} is insufficient. 25 refs., 6 figs., 6 tabs.

  1. Cane molasses fermentation for continuous ethanol production in an immobilized cells reactor by Saccharomyces cerevisiae

    Energy Technology Data Exchange (ETDEWEB)

    Ghorbani, Farshid; Younesi, Habibollah; Esmaeili Sari, Abbas [Department of Environmental Science, Faculty of Natural Resources and Marine Sciences, Tarbiat Modares University, Noor, P.O. Box: 64414-356 (Iran); Najafpour, Ghasem [Department of Chemical Engineering, Faculty of Engineering, Noshirvani University of Technology, Babol (Iran)

    2011-02-15

    Sodium-alginate immobilized yeast was employed to produce ethanol continuously using cane molasses as a carbon source in an immobilized cell reactor (ICR). The immobilization of Saccharomyces cerevisiae was performed by entrapment of the cell cultured media harvested at exponential growth phase (16 h) with 3% sodium alginate. During the initial stage of operation, the ICR was loaded with fresh beads of mean diameter of 5.01 mm. The ethanol production was affected by the concentration of the cane molasses (50, 100 and 150 g/l), dilution rates (0.064, 0.096, 0.144 and 0.192 h{sup -1}) and hydraulic retention time (5.21, 6.94, 10.42 and 15.63 h) of the media. The pH of the feed medium was set at 4.5 and the fermentation was carried out at an ambient temperature. The maximum ethanol production, theoretical yield (Y{sub E/S}), volumetric ethanol productivity (Q{sub P}) and total sugar consumption was 19.15 g/l, 46.23%, 2.39 g l{sup -1} h{sup -1} and 96%, respectively. (author)

  2. Alcohol production from sterilized and non-sterilized molasses by Saccharomyces cerevisiae immobilized on brewer's spent grains in two types of continuous bioreactor systems

    International Nuclear Information System (INIS)

    Kopsahelis, Nikolaos; Bosnea, Loulouda; Bekatorou, Argyro; Tzia, Constantina; Kanellaki, Maria

    2012-01-01

    In this work an integrated cost effective system for continuous alcoholic fermentation of a cheap raw material (molasses) is described, involving yeast immobilized by a simple method on brewer's spent grains, able to ferment in the temperature range 30–40 °C, and two types of bioreactors, a Multistage Fixed Bed Tower (MFBT) and a Packed Bed reactor (PB). The MFBT bioreactor gave better results regarding ethanol concentration, productivity and conversion. Furthermore, the use of sterilized and non-sterilized molasses, fed in two similar MFBT bioreactors, showed that ethanol concentration (kg m −3 ) was significantly (p −3 at 35 °C and 44.2–48.2 kg m −3 at 40 °C), compared to sterilized molasses, where ethanol concentration ranged from 35.6 to 46.6 kg m −3 at 35 °C and 30.8–44.2 kg m −3 at 40 °C. During 32 days of continuous operation using non-sterilized molasses no contamination was observed. Industrialization of the proposed system seems to have a potential, mainly due to its high fermentation efficiency and the obtained high operational stability. -- Highlights: ► An integrated cost effective system for continuous alcoholic fermentation. ► Efficient conversion of non-sterilized molasses to ethanol. ► No need for additional treatments to prevent contamination. ► Results showed high fermentation efficiency and high operational stability.

  3. Highly Selective Continuous Flow Hydrogenation of Cinnamaldehyde to Cinnamyl Alcohol in a Pt/SiO2 Coated Tube Reactor

    Directory of Open Access Journals (Sweden)

    Yang Bai

    2018-02-01

    Full Text Available A novel continuous flow process for selective hydrogenation of α, β-unsaturated aldehyde (cinnamaldehyde, CAL to the unsaturated alcohol (cinnamyl alcohol, COL has been reported in a tube reactor coated with a Pt/SiO2 catalyst. A 90% selectivity towards the unsaturated alcohol was obtained at the aldehyde conversion of 98.8%. This is a six-fold improvement in the selectivity compared to a batch process where acetals were the main reaction products. The increased selectivity in the tube reactor was caused by the suppression of acid sites responsible for the acetal formation after a short period on stream in the continuous process. In a fixed bed reactor, it had a similar acetal suppression phenomenon but showed lower product selectivity of about 47–72% due to mass transfer limitations. A minor change in selectivity and conversion caused by product inhibition was observed during the 110 h on stream with a turnover number (TON reaching 3000 and an alcohol production throughput of 0.36 kg gPt−1 day−1 in the single tube reactor. The catalysts performance after eight reaction cycles was fully restored by calcination in air at 400 °C. The tube reactors provide an opportunity for process intensification by increasing the reaction rates by a factor of 2.5 at the reaction temperature of 150 °C compared to 90 °C with no detrimental effects on catalyst stability or product selectivity.

  4. Electro-Fenton treatment of mature landfill leachate in a continuous flow reactor

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Hui, E-mail: eeng@whu.edu.cn [Department of Environmental Engineering, Hubei Biomass-Resource Chemistry and Environmental Biotechnology Key Laboratory, Wuhan University, P.O. Box C319, Luoyu Road 129, Wuhan 430079 (China); Ran, Xiaoni; Wu, Xiaogang [Department of Environmental Engineering, Hubei Biomass-Resource Chemistry and Environmental Biotechnology Key Laboratory, Wuhan University, P.O. Box C319, Luoyu Road 129, Wuhan 430079 (China)

    2012-11-30

    Highlights: Black-Right-Pointing-Pointer CSTR mode was used for COD removal of landfill leachate by Fered-Fenton process. Black-Right-Pointing-Pointer The complete mixing condition in the CSTR was verified. Black-Right-Pointing-Pointer A modified pseudo-first order kinetic model was developed. Black-Right-Pointing-Pointer The effects of important parameters on COD removal were investigated. Black-Right-Pointing-Pointer The organic components before and after treatment were determined by GC-MS. - Abstract: The treatment of mature landfill leachate by EF-Fere (also called Fered-Fenton) method was carried out in a continuous stirred tank reactor (CSTR) using Ti/RuO{sub 2}-IrO{sub 2}-SnO{sub 2}-TiO{sub 2} mesh anodes and Ti mesh cathodes. The effects of important parameters, including initial pH, inter-electrode gap, H{sub 2}O{sub 2} to Fe{sup 2+} molar ratio, H{sub 2}O{sub 2} dosage and hydraulic retention time, on COD removal were investigated. The results showed that the complete mixing condition was fulfilled in the electrochemical reactor employed in this study and COD removal followed a modified pseudo-first order kinetic model. The COD removal efficiency increased with the decrease of H{sub 2}O{sub 2} to Fe{sup 2+} molar ratio and hydraulic retention time. There existed an optimal inter-electrode gap or H{sub 2}O{sub 2} dosage so that the highest COD removal was achieved. Nearly the same COD removal was obtained at initial pH 3 and 5, but the steady state was quickly achieved at initial pH 3. The organic pollutants in the leachate were analyzed through a gas chromatography coupled with mass spectrometry (GC-MS) system. About 73 organics were detected in the leachate, and 52 of which were completely removed after EF-Fere process.

  5. Investigation of techniques for the application of safeguards to a continuously fuelled reactor

    International Nuclear Information System (INIS)

    Hodgkinson, J.G.; Head, D.A.

    1978-03-01

    The following three areas of prime safeguards concern are analyzed: 1) at the reactor face, where spent fuel is first removed from the channel, 2) along the system for transporting spent fuel from the reactor to the storage bay, and 3) in the spent fuel storage bay. The program is designed to develop techniques and instruments to safeguard these areas

  6. Enhanced decolourisation of Acid Orange 7 in a continuous UASB reactor with quinones as redox mediators.

    NARCIS (Netherlands)

    Cervantes, F.J.; Zee, van der F.P.; Lettinga, G.; Field, J.A.

    2001-01-01

    The reductive biotransformation of acid orange 7 (AO7) was explored in a lab-scale upflow anaerobic sludge blanket (UASB) reactor at low hydraulic residence times (HRT). A colour removal of 85% was achieved when the reactor was operated at a HRT of 6 hours, but decreased up to 70% when the HRT was

  7. Closing the Loop by Combining UASB Reactor and Reactive Bed Filetr Technology for wastewater Treatment : Modelling and Practical Approaches

    OpenAIRE

    Rodríguez-Gómez, Raúl

    2016-01-01

    A laboratory-scale upflow anaerobic sludge blanket (UASB) reactor followed by a packed bed reactor (PBR) filled with Sorbulite® in the lower part and Polonite® in the upper part was used to treat household wastewater in a 50-week experiment. A model was developed to describe the performance of the UASB reactor, including mass transfer through the film around anaerobic granules, intra-particle diffusion and bioconversion of the substrate. In a second model, a numerical expression describing th...

  8. Biodegradation of a commercial mixture of the herbicides atrazine and S-metolachlor in a multi-channel packed biofilm reactor.

    Science.gov (United States)

    Cabrera-Orozco, Alberto; Galíndez-Nájera, Silvia Patricia; Ruiz-Ordaz, Nora; Galíndez-Mayer, Juvencio; Martínez-Jerónimo, Fernando

    2017-11-01

    Atrazine and S-metolachlor are two of the most widely used herbicides for agricultural purposes; consequently, residues of both compounds and their metabolites had been detected in ground and superficial waters. Unlike atrazine, the complete degradation of metolachlor has not been achieved. Hence, the purpose of this research is to study the biodegradation of a commercial mixture of atrazine and S-metolachlor in a prototype of a multi-channel packed-bed-biofilm reactor (MC-PBR) designed with the aim of solving the problems of pressure drop and oxygen transfer, typically found on this type of bioreactors.Because the removal efficiency of the herbicides was increased when Candida tropicalis was added to the original microbial community isolated, the reactor was inoculated with this enriched community. The operational conditions tested in batch and continuous mode did not affect the removal efficiency of atrazine; however, this was not the case for S-metolachlor. The removal rates and efficiencies showed a notable variation along the MC-PBR operation.

  9. Continuous formation of N-chloro-N,N-dialkylamine solutions in well-mixed meso-scale flow reactors

    Science.gov (United States)

    Jolley, Katherine E

    2015-01-01

    Summary The continuous flow synthesis of a range of organic solutions of N,N-dialkyl-N-chloramines is described using either a bespoke meso-scale tubular reactor with static mixers or a continuous stirred tank reactor. Both reactors promote the efficient mixing of a biphasic solution of N,N-dialkylamine in organic solvent, and aqueous sodium hypochlorite to achieve near quantitative conversions, in 72–100% in situ yields, and useful productivities of around 0.05 mol/h with residence times from 3 to 20 minutes. Initial calorimetric studies have been carried out to inform on reaction exotherms, rates and safe operation. Amines which partition mainly in the organic phase require longer reaction times, provided by the CSTR, to compensate for low mass transfer rates in the biphasic system. The green metrics of the reaction have been assessed and compared to existing procedures and have shown the continuous process is improved over previous procedures. The organic solutions of N,N-dialkyl-N-chloramines produced continuously will enable their use in tandem flow reactions with a range of nucleophilic substrates. PMID:26734089

  10. Continuous formation of N-chloro-N,N-dialkylamine solutions in well-mixed meso-scale flow reactors

    Directory of Open Access Journals (Sweden)

    A. John Blacker

    2015-12-01

    Full Text Available The continuous flow synthesis of a range of organic solutions of N,N-dialkyl-N-chloramines is described using either a bespoke meso-scale tubular reactor with static mixers or a continuous stirred tank reactor. Both reactors promote the efficient mixing of a biphasic solution of N,N-dialkylamine in organic solvent, and aqueous sodium hypochlorite to achieve near quantitative conversions, in 72–100% in situ yields, and useful productivities of around 0.05 mol/h with residence times from 3 to 20 minutes. Initial calorimetric studies have been carried out to inform on reaction exotherms, rates and safe operation. Amines which partition mainly in the organic phase require longer reaction times, provided by the CSTR, to compensate for low mass transfer rates in the biphasic system. The green metrics of the reaction have been assessed and compared to existing procedures and have shown the continuous process is improved over previous procedures. The organic solutions of N,N-dialkyl-N-chloramines produced continuously will enable their use in tandem flow reactions with a range of nucleophilic substrates.

  11. Electrochemical removal of fluoride from water by PAOA-modified carbon felt electrodes in a continuous flow reactor.

    Science.gov (United States)

    Cui, Hao; Qian, Yan; An, Hao; Sun, Chencheng; Zhai, Jianping; Li, Qin

    2012-08-01

    A novel poly(aniline-co-o-aminophenol) (PAOA) modified carbon felt electrode reactor was designed and investigated for fluoride removal from aqueous solutions. This reactor design is innovative because it operates under a wider pH range because of coating with a copolymer PAOA ion exchange film. In addition, contaminant mass transfer from bulk solution to the electrode surface is enhanced by the porous carbon felt as an electron-conducting carrier material compared to other reactors. The electrically controlled anion exchange mechanism was investigated by X-ray photoelectron spectroscopy and cyclic voltammetry. The applicability of the reactor in the field was tested through a series of continuous flow experiments. When the flow rate and initial fluoride concentration were increased, the breakthrough curve became sharper, which lead to a decrease in the breakthrough time and the defluoridation capacity of the reactor. The terminal potential values largely influenced fluoride removal by the reactor and the optimal defluoridation efficiency was observed at around 1.2V. The breakthrough capacities were all >10mg/g over a wide pH range (pH 5-9) with an initial fluoride concentration of 10mg/L. Consecutive treatment-regeneration studies over a week (once each day) revealed that the PAOA-modified carbon felt electrode could be effectively regenerated for reuse. The PAOA-modified carbon felt electrode reactor is a promising system that could be made commercially available for fluoride removal from aqueous solutions in field applications. Copyright © 2012 Elsevier Ltd. All rights reserved.

  12. The burnup capabilities of the Deep Burn Modular Helium Reactor analyzed by the Monte Carlo Continuous Energy Code MCB

    Energy Technology Data Exchange (ETDEWEB)

    Talamo, Alberto E-mail: alby@neutron.kth.se; Gudowski, Waclaw E-mail: wacek@neutron.kth.se; Venneri, Francesco E-mail: venneri@lanl.gov

    2004-01-01

    We have investigated the waste actinide burnup capabilities of a Gas Turbine Modular Helium Reactor (GT-MHR, similar to the reactor being designed by General Atomics and Minatom for surplus weapons plutonium destruction) with the Monte Carlo Continuous Energy Burnup Code MCB, an extension of MCNP developed at the Royal Institute of Technology in Stockholm and University of Mining and Metallurgy in Krakow. The GT-MHR is a gas-cooled, graphite-moderated reactor, which can be powered with a wide variety of fuels, like thorium, uranium or plutonium. In the present work, the GT-MHR is fueled with the transuranic actinides contained in Light Water Reactors (LWRs) spent fuel for the purpose of destroying them as completely as possible with minimum reliance on multiple reprocessing steps. After uranium extraction from the LWR spent fuel (UREX), the remaining waste actinides, including plutonium are partitioned into two distinct types of fuel for use in the GT-MHR: Driver Fuel (DF) and Transmutation Fuel (TF). The DF supplies the neutrons to maintain the fission chain reaction, whereas the TF emphasizes neutron capture to induce a deep burn transmutation and provide reactivity control by a negative feedback. When used in this mode, the GT-MHR is called Deep Burn Modular Helium Reactor (DB-MHR). Both fuels are contained in a structure of triple isotropic coated layers, TRISO coating, which has been proven to retain fission products up to 1600 deg. C and is expected to remain intact for hundreds of thousands of years after irradiation. Other benefits of this reactor consist of: a well-developed technology, both for the graphite-moderated core and the TRISO structure, a high energy conversion efficiency (about 50%), well established passive safety mechanism and a competitive cost. The destruction of more than 94% of {sup 239}Pu and the other geologically problematic actinide species makes this reactor a valid proposal for the reduction of nuclear waste and the prevention of

  13. The burnup capabilities of the Deep Burn Modular Helium Reactor analyzed by the Monte Carlo Continuous Energy Code MCB

    International Nuclear Information System (INIS)

    Talamo, Alberto; Gudowski, Waclaw; Venneri, Francesco

    2004-01-01

    We have investigated the waste actinide burnup capabilities of a Gas Turbine Modular Helium Reactor (GT-MHR, similar to the reactor being designed by General Atomics and Minatom for surplus weapons plutonium destruction) with the Monte Carlo Continuous Energy Burnup Code MCB, an extension of MCNP developed at the Royal Institute of Technology in Stockholm and University of Mining and Metallurgy in Krakow. The GT-MHR is a gas-cooled, graphite-moderated reactor, which can be powered with a wide variety of fuels, like thorium, uranium or plutonium. In the present work, the GT-MHR is fueled with the transuranic actinides contained in Light Water Reactors (LWRs) spent fuel for the purpose of destroying them as completely as possible with minimum reliance on multiple reprocessing steps. After uranium extraction from the LWR spent fuel (UREX), the remaining waste actinides, including plutonium are partitioned into two distinct types of fuel for use in the GT-MHR: Driver Fuel (DF) and Transmutation Fuel (TF). The DF supplies the neutrons to maintain the fission chain reaction, whereas the TF emphasizes neutron capture to induce a deep burn transmutation and provide reactivity control by a negative feedback. When used in this mode, the GT-MHR is called Deep Burn Modular Helium Reactor (DB-MHR). Both fuels are contained in a structure of triple isotropic coated layers, TRISO coating, which has been proven to retain fission products up to 1600 deg. C and is expected to remain intact for hundreds of thousands of years after irradiation. Other benefits of this reactor consist of: a well-developed technology, both for the graphite-moderated core and the TRISO structure, a high energy conversion efficiency (about 50%), well established passive safety mechanism and a competitive cost. The destruction of more than 94% of 239 Pu and the other geologically problematic actinide species makes this reactor a valid proposal for the reduction of nuclear waste and the prevention of

  14. Continuous Assessment of Safety Margin for the 14-MW TRIGA Reactor

    International Nuclear Information System (INIS)

    Ciocanescu, M.; Georgescu, D.; Doru, O.

    2008-01-01

    The assessment of reactor safety implies analyses of the reactor and its systems response to a range of postulated initiating events (such as malfunction or failures of equipment, operator errors, external events and so on which could lead to either anticipated operational occurrences or to accident conditions. Decreasing in heat removal by the reactor cooling system may be considered as a process disturbance which may lead to a postulated initiating event. The cold source for the reactor cooling system, in case of TRIGA-14 MW reactor is the atmosphere by the secondary cooling towers. The ability to evacuate the heat produced by the reactor core ranges between the outlet temperature of the core flow and the outdoors temperature in air, which is subject to season and day variation. Selected values for safety limits, safety system settings and limiting condition(s) are derived from safety analysis and are consistent with the operational state of the reactor. When a limiting condition for safe operation is not satisfied, the operating personal is supposed to take the appropriate action(s) to ensure safety. Operating requirements and the safety system are presented. The reactor operating safety parameters from the main Data Acquisition System are transferred to an AT personal computer. These selected parameters are the following: - average inlet temperature which is calculated as an average temperature measured by 20 type K thermocouples distributed within a 4 x 5 matrix located on the top of the reactor core; - average outlet temperature which is calculated as an average record from 10 type K thermocouples placed in the outlet pipe; - average flow rate which is calculated as an average value from four transducers (two for the inlet flow rate and two for the outlet flow rate). Due to its high instability, this value is also filtered using a two-pole low-pass filter (software); - reactor thermal power value derivable from the previous parameters or obtained from the

  15. Treatment of gaseous effluents by using surface discharge plasma in continuous reactors: Process modelling and simulation

    OpenAIRE

    Assadi , Aymen ,; Bouzaza , Abdelkrim; Wolbert , Dominique

    2015-01-01

    International audience; In the present work, the oxidation of isovaleraldehyde, a typical pollutant of indoor air, is investigated by using two different plasma DBD reactors: cylindrical and planar reactor. The study of the influence of the specific energy shows that its increment is accompanied by an increase of the removal efficiency. In fact, when specific energy extends three times, the removal efficiency is increased from 5 to 40%. Moreover an increase of the specific energy induces a hi...

  16. Continuous control of pH value and chloride concentration in a water coolant of nuclear reactors

    International Nuclear Information System (INIS)

    Moskvin, L.N.; Krasnoperov, V.M.; Fokina, K.G.; Vilkov, N.Ya.

    1975-01-01

    Potentiometry method with the use of flowing cells with two identical electrodes is the simplest and most safe for continuous pH value and chloride control in nuclear reactor circulating circuits. The constant potential on the comparison electrode may be provided by supplying the analyzed solution to it through the ion resin filter of mixed operation. The pos--sibility of a continuous pH value monitoring in a flowing cell with two glass electrodes in parallel is considered. To monitor clorides a cell with two porous chlorine-silver electrodes positioned in series is used. The cells of the design described are shown to be workable in water simulating coolants for water-cooled reactors

  17. Esterification of Fatty Acids with Short-Chain Alcohols over Commercial Acid Clays in a Semi-Continuous Reactor

    Directory of Open Access Journals (Sweden)

    Mohamed H. Frikha

    2009-11-01

    Full Text Available Production of fatty acid esters from stearic, oleic, and palmitic acids and short-chain alcohols (methanol, ethanol, propanol, and butanol for the production of biodiesel was investigated in this work. A series of montmorillonite-based clays catalysts (KSF, KSF/0, KP10, and K10 were used as acidic catalysts. The influence of the specific surface area and the acidity of the catalysts on the esterification rate were investigated. The best catalytic activities were obtained with KSF/0 catalyst. The esterification reaction has been carried out efficiently in a semi-continuous reactor at 150°C temperature higher than the boiling points of water and alcohol. The reactor used enabled the continuous removal of water and esterification with hydrated alcohol (ethanol 95% without affecting the original activity of the clay.

  18. The Texts of the Instruments Concerning the Agency's Assistance to Indonesia for the Continuation of a Research Reactor Project

    International Nuclear Information System (INIS)

    1970-01-01

    The texts of the Supply Agreement between the Agency and the Governments of Indonesia and the United States of America, and of the Project Agreement between the Agency and the Government of Indonesia concerning the Agency's assistance to that Government for the continuation of a research reactor project, are reproduced in this document for the information of all Members. Both Agreements entered into force on 19 December 1969.

  19. Design and simulation of an activated sludge unit associated to a continuous reactor to remove heavy metals

    Energy Technology Data Exchange (ETDEWEB)

    D`Avila, J.S.; Nascimento, R.R. [Ambientec Consultoria Ltda., Aracaju, SE (Brazil)

    1993-12-31

    A software was developed to design and simulate an activated sludge unit associated to a new technology to remove heavy metals from wastewater. In this process, a continuous high efficiency biphasic reactor operates by using particles of activated peat in conjugation with the sludge unit. The results obtained may be useful to increase the efficiency or to reduce the design and operational costs involved in a activated sludge unit. (author). 5 refs., 2 tabs.

  20. The Texts of the Instruments Concerning the Agency's Assistance to Indonesia for the Continuation of a Research Reactor Project

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1970-02-08

    The texts of the Supply Agreement between the Agency and the Governments of Indonesia and the United States of America, and of the Project Agreement between the Agency and the Government of Indonesia concerning the Agency's assistance to that Government for the continuation of a research reactor project, are reproduced in this document for the information of all Members. Both Agreements entered into force on 19 December 1969.