DEGRADATION OF AROMATIC COMPOUNDS USING MOVING BED BIOFILM REACTORS

Directory of Open Access Journals (Sweden)

B. Ayati, H. Ganjidoust, M. Mir Fattah

2007-04-01

Full Text Available For biological treatment of water, there are many different biofilm systems in use. Examples of them are trickling filters, rotating biological contactors, fixed media submerged biofilters, granular media biofilters and fluidized bed reactors. They all have their advantages and disadvantages. Hence, the Moving Bed Biofilm Reactor process was developed in Norway in the late 1980s and early 1990s to adopt the best features of the activated sludge process as well as those of the biofilter processes, without including the worst. Two cylindrical moving bed biofilm reactors were used in this study working in upflow stream conditions. Experiments have been done in aerobic batch flow regime. Laboratory experiments were conducted at room temperature (23–28C and synthetic wastewater comprising a composition of phenol and hydroquinone in each reactor as the main organic constituents, plus balanced nutrients and alkalinity were used to feed the reactor. The ratio of influent to effluent COD was determined at different retention times. The results indicated that the removal efficiency of each selected compound is affected by the detention time. At low phenol and hydroquinone concentration (from 700 to 1000 mg/L maximum removal efficiency (over 80 % was obtained. By further increasing in COD loading rate up to 3000 mg/L, a decrease in COD removal rate was occurred. In the reactor containing pyrogallol in COD of 1500 mg/L, the removal rate decreased to 10 percent because of its toxicity for microorganisms.

Mixing and scale affect moving bed biofilm reactor (MBBR) performance

NARCIS (Netherlands)

Kamstra, Andries; Blom, Ewout; Terjesen, Bendik Fyhn

2017-01-01

Moving Bed Biofilm Reactors (MBBR) are used increasingly in closed systems for farming of fish. Scaling, i.e. design of units of increasing size, is an important issue in general bio-reactor design since mixing behaviour will differ between small and large scale. Research is mostly performed on

A moving-bed gasifier with internal recycle of pyrolysis gas

NARCIS (Netherlands)

Susanto, H.; Beenackers, A.A C M

A co-current moving bed gasifier with internal recycle and separate combustion of pyrolysis gas has been developed with the aim of producing a design suitable for scaling-up downdraft gasifiers while maintaining a low tar content in the producer gas. Using wood chips with a moisture content of 7-9

Conversion of metallurgical coke and coal using a Coal Direct Chemical Looping (CDCL) moving bed reactor

International Nuclear Information System (INIS)

Luo, Siwei; Bayham, Samuel; Zeng, Liang; McGiveron, Omar; Chung, Elena; Majumder, Ankita; Fan, Liang-Shih

2014-01-01

Highlights: • Accumulated more than 300 operation hours were accomplished for the moving bed reducer reactor. • Different reactor operation variables were investigated with optimal conditions identified. • High conversions of sub-bituminous coal and bituminous coal were achieved without flow problems. • Co-current and counter-current contact modes were tested and their applicability was discussed. - Abstract: The CLC process has the potential to be a transformative commercial technology for a carbon-constrained economy. The Ohio State University Coal Direct Chemical Looping (CDCL) process directly converts coal, eliminating the need for a coal gasifier oran air separation unit (ASU). Compared to other solid-fuel CLC processes, the CDCL process is unique in that it consists of a countercurrent moving bed reducer reactor. In the proposed process, coal is injected into the middle of the moving bed, whereby the coal quickly heats up and devolatilizes, splitting the reactor roughly into two sections with no axial mixing. The top section consists of gaseous fuel produced from the coal volatiles, and the bottom section consists of the coal char mixed with the oxygen carrier. A bench-scale moving bed reactor was used to study the coal conversion with CO 2 as the enhancing gas. Initial tests using metallurgical cokefines as feedstock were conducted to test the effects of operational variables in the bottom section of the moving bed reducer, e.g., reactor temperature, oxygen carrier to char ratio, enhancer gas CO 2 flow rate, and oxygen carrier flow rates. Experiments directly using coal as the feedstock were subsequently carried out based on these test results. Powder River Basin (PRB) coal and Illinois #6 coal were tested as representative sub-bituminous and bituminous coals, respectively. Nearly complete coal conversion was achieved using composite iron oxide particles as the oxygen carriers without any flow problems. The operational results demonstrated that a

A novel approach for harnessing biofilm communities in moving bed biofilm reactors for industrial wastewater treatment

OpenAIRE

Joe A. Lemire; Marc A. Demeter; Iain George; Howard Ceri; Raymond J. Turner

2015-01-01

Moving bed biofilm reactors (MBBRs) are an effective biotechnology for treating industrial wastewater. Biomass retention on moving bed biofilm reactor (MBBR) carriers (biofilm support materials), allows for the ease-of-operation and high treatment capacity of MBBR systems. Optimization of MBBR systems has largely focused on aspects of carrier design, while little attention has been paid to enhancing strategies for harnessing microbial biomass. Previously, our research group demonstrated that ...

Fiscal 1995 achievement report. Development of entrained bed coal gasification power plant (Part 5 - Surveys and studies of demonstration plant); 1995 nendo seika hokokusho. Funryusho sekitan gaska hatsuden plant kaihatsu - Sono 5. Jissho plant ni kansuru chosa kenkyu hen

Energy Technology Data Exchange (ETDEWEB)

NONE

1996-03-01

Surveys and studies were conducted concerning a demonstration plant for establishing the technology of integrated coal gasification combined cycle, and the fiscal 1995 results are compiled. In this fiscal year, a demonstration plant conceptual design was prepared for assuring smooth transition from a pilot plant to a commercial plant. The design followed the system employed at the Nakoso pilot plant for its gasification power generation. It was decided that the gasification furnace be of the air-blown (oxygen enriched) 2-stage entrained bed type, that the desulfurization system be of the dry type 2-stage fluidized bed type, the dedusting system be of the dry type granular bed type (moving bed type), that the combined cycle power facility be derived from the commercialized gas turbine, and that the cycle of the steam system agree with the integrated coal gasification combined cycle system now under discussion. Studies were made, which covered heat efficiency (generating end/sending end), heat/matter balance, process flow, gas turbine/steam system optimization, comparison in performance with a pilot plant with its dimensions increased, estimation of the performance of each of the facilities, estimation of the construction cost, calculation of the generation cost, environmental friendliness, operating characteristics, acceptable coal types, and the like. (NEDO)

Experimental purification of paclitaxel from a complex mixture of taxanes using a simulated moving bed

Directory of Open Access Journals (Sweden)

M. A. Cremasco

2009-03-01

Full Text Available A laboratory-scale simulated moving bed (SMB was designed and tested for the separation of paclitaxel, a powerful anti-cancer agent known as Taxol@, from impurities of a plant tissue culture (PTC broth. The innovative strategy of a pseudo-binary model, where mixtures A and B were treated as single solutes A and B, was used in the linear standing wave analysis to fix the SMB operating parameters for a multicomponent and complex system. Linear standing wave design was used to specify the zone flow rates and the switching time for the laboratory-scale SMB unit, with two steps of separation. The SMB consists of four packed columns, where each column is 12.5 cm in length and 1.5 cm in diameter. Two sequential separation steps were used to recover paclitaxel from a small feed batch (less than one liter. Placlitaxel was recovered from the complex plant tissue culture broth in 82% yield and 72% purity.

Advantages and applications of moving bed technology in urban and industrial waste waters; Ventajas y aplicaciones de la tecnologia de lecho movil en aguas residuales urbanas e industriales

Energy Technology Data Exchange (ETDEWEB)

Larrea Urcola, A.; Zalakain Bengoa, G.; Larrea Ucola, L.; Abad Alba, A.

2004-07-01

Moving bed technology is a new biological treatment by activated sludge where the biomass grows attached to a inert media (plastic) that moves free along the reactor. The main advantages of this technology are the reduction of the reactor volume, simplicity of operation and the easiest way for the upgrading of plants. Results of different industrial applications are shown together with the latest researches lines that combine organic matter and nitrogen removal. (Author) 12 refs.

Down-flow moving-bed gasifier with catalyst recycle

Science.gov (United States)

Halow, John S.

1999-01-01

The gasification of coal and other carbonaceous materials by an endothermic gasification reaction is achieved in the presence of a catalyst in a down-flow, moving-bed gasifier. Catalyst is removed along with ash from the gasifier and is then sufficiently heated in a riser/burner by the combustion of residual carbon in the ash to volatilize the catalyst. This volatilized catalyst is returned to the gasifier where it uniformly contacts and condenses on the carbonaceous material. Also, the hot gaseous combustion products resulting from the combustion of the carbon in the ash along with excess air are introduced into the gasifier for providing heat energy used in the endothermic reaction.

Exergy analysis of a circulating fluidized bed boiler cogeneration power plant

International Nuclear Information System (INIS)

Gürtürk, Mert; Oztop, Hakan F.

2016-01-01

Highlights: • Analysis of energy and exergy for a cogeneration power plant have been performed. • This plant has circulating fluidized bed boiler. • Energy and exergy efficiencies of the boiler are obtained as 84.65% and 29.43%, respectively. • Exergy efficiency of the plant was calculated as 20%. - Abstract: In this study, energy and exergy analysis of a cogeneration power plant have been performed. The steam which is produced by the cogeneration power plant is used for salt production and most important part of the cogeneration power plant is the circulation fluidized bed boiler. Energy and exergy efficiency of the circulation fluidized bed boiler were found as 84.65% and 29.43%, respectively. Exergy destruction of the circulation fluidized bed boiler was calculated as 21789.39 kW and 85.89% of exergy destruction in the plant. The automation system of the cogeneration power plant is insufficient. Exergy efficiency of the plant was calculated as 20%. Also, some design parameters increasing energy losses were determined.

Influence of thermophoresis on particle removal in a moving granular bed filter and heat exchanger

International Nuclear Information System (INIS)

Rudnick, S.N.; First, M.W.; Price, J.M.

1981-01-01

Bench-scale investigations were made to determine the influence of thermophoresis on particle removal in a moving granular bed filter. A continuous flow of 2-mm diameter ceramic granules at ambient temperature entered the top of the filter and moved slowly downward under the influence of gravity countercurrent to the gas stream. At an inlet gas temperature of 240 0 C, gas mass velocity of 0.12 kg/(s.m 2 ), and granule velocities up to 0.015 cm/s, clean bed collection efficiency for a submicrometer sodium chloride aerosol was found to increase the more the gas was cooled, indicating that thermophoretic forces were playing a measurable role in particle collection

Effect of Gas Recycling on the Performance of a Moving Bed Temperature-Swing (MBTSA Process for CO2 Capture in a Coal Fired Power Plant Context

Directory of Open Access Journals (Sweden)

Giorgia Mondino

2017-05-01

Full Text Available A mathematical model of a continuous moving-bed temperature-swing adsorption (MBTSA process for post-combustion CO2 capture in a coal-fired power plant context has been developed. Process simulations have been done using single component isotherms and measured gas diffusion parameters of an activated carbon adsorbent. While a simple process configuration with no gas re-circulation gives quite low capture rate and CO2 purity, 86% and 65%, respectively, more advanced process configurations where some of the captured gas is recirculated to the incoming flue gas drastically increase both the capture rate and CO2 purity, the best configuration reaching capture rate of 86% and CO2 purity of 98%. Further improvements can be achieved by using adsorbents with higher CO2/N2 selectivity and/or higher temperature of the regeneration section.

Comparison between moving bed-membrane bioreactor (MB-MBR) and membrane bioreactor (MBR) systems: influence of wastewater salinity variation.

Science.gov (United States)

Di Trapani, Daniele; Di Bella, Gaetano; Mannina, Giorgio; Torregrossa, Michele; Viviani, Gaspare

2014-06-01

Two pilot plant systems were investigated for the treatment of wastewater subject to a gradual increase of salinity. In particular, a membrane bioreactor (MBR) and a moving bed biofilm membrane bioreactor (MB-MBR) were analyzed. Carbon and ammonium removal, kinetic constants and membranes fouling rates have been assessed. Both plants showed very high efficiency in terms of carbon and ammonium removal and the gradual salinity increase led to a good acclimation of the biomass, as confirmed by the respirometric tests. Significant biofilm detachments from carriers were experienced, which contributed to increase the irreversible superficial cake deposition. However, this aspect prevented the pore fouling tendency in the membrane module of MB-MBR system. On the contrary, the MBR pilot, even showing a lower irreversible cake deposition, was characterized by a higher pore fouling tendency. Copyright © 2014 Elsevier Ltd. All rights reserved.

Techno-economic studies on transportable moving-bed onion irradiator

International Nuclear Information System (INIS)

Krishnamurthy, K.; Sharma, K.S.S.; Deshmukh, V.P.; Bongirwar, D.R.; Nair, K.V.V.; Patil, K.B.

1984-01-01

The paper presents the optimisation studies and the design features of a transportable irradiator evolved to demonstrate the techno-economic advantage of the irradiation process at village level. A brief outline is also given of the computer programme generated and employed to optimise the source-target configuration based on a narrow plane source moving-bed irradiation concept that aimed at achieving a simplified product handling system and cost effective design of the biological shield and controls for the irradiator. The engineering features of the irradiator along with a summary of the analysis of the economics of the application of the process are also given. (author)

Wear oxidation of evaporator coils in fluidised bed captive power plants

International Nuclear Information System (INIS)

Ghosal, S.K.; De, P.K.

2000-01-01

Combustion of pulverised coal or gas to form steam in thermal power plants is a common practice. Corrosion of water-wall, superheater and reheater tubes is the typical problem faced in these power plants. Modification of process conditions, redesigning of equipment and selection of more corrosion resistant materials are few methods which have been tried to combat corrosion to a certain extent. Restricted heat transfer efficiency is another problem associated with these power plants. In order to bring upon improvements, fluidized bed combustors are being used in some advanced thermal power plants at present because of excellent combustion and heat transfer efficiencies. Even with low grade coals, higher combustion efficiency could be achieved in these combustors due to excellent gas/solid chemical reactivity at relatively low reaction temperatures. Further improvements in in-bed heat transfer and bed temperature uniformity have been possible with the use of sand in bed. However, erosion, corrosion and combined erosion/corrosion are some of the major modes of material degradation associated with these fluidized bed combustors using sand. Recently in a captive power unit using bubbling fluidized bed combustors containing sand, evaporator coils made of carbon steel were seen to be severely affected by erosion corrosion. The directional nature of metal removal from the studs, tube OD and ultimately the rupture of the thinned tube wall confirmed the above observation. Microstructural examinations showed loss of carbon at certain places including those near the leaked/punctured regions at the prevailing bed temperature of 850 deg C. This paper describes the detailed investigations carried out on wear oxidation phenomenon occurred in a captive thermal power plant using advanced bubbling fluidized bed combustors. (author)

Gasification of solid waste — potential and application of co-current moving bed gasifiers

NARCIS (Netherlands)

Groeneveld, M.J.; van Swaaij, Willibrordus Petrus Maria

1979-01-01

A review is given of gasification processes for solid fuels with special emphasis on waste gasification. Although the co-current moving bed gasifier has not been under consideration for a long time, it offers interesting possibilities for waste gasification. Some operational data are given. Two

Early processing variations in selective attention to the color and direction of moving stimuli during 30 days head-down bed rest

Science.gov (United States)

Wang, Lin-Jie; He, Si-Yang; Niu, Dong-Bin; Guo, Jian-Ping; Xu, Yun-Long; Wang, De-Sheng; Cao, Yi; Zhao, Qi; Tan, Cheng; Li, Zhi-Li; Tang, Guo-Hua; Li, Yin-Hui; Bai, Yan-Qiang

2013-11-01

Dynamic variations in early selective attention to the color and direction of moving stimuli were explored during a 30 days period of head-down bed rest. Event-related potentials (ERPs) were recorded at F5, F6, P5, P6 scalp locations in seven male subjects who attended to pairs of bicolored light emitting diodes that flashed sequentially to produce a perception of movement. Subjects were required to attend selectively to a critical feature of the moving target, e.g., color or direction. The tasks included: a no response task, a color selective response task, a moving direction selective response task, and a combined color-direction selective response task. Subjects were asked to perform these four tasks on: the 3rd day before bed rest; the 3rd, 15th and 30th day during the bed rest; and the 5th day after bed rest. Subjects responded quickly to the color than moving direction and combined color-direction response. And they had a longer reaction time during bed rest on the 15th and 30th day during bed rest after a relatively quicker response on the 3rd day. Using brain event-related potentials technique, we found that in the color selective response task, the mean amplitudes of P1 and N1 for target ERPs decreased in the 3rd day during bed rest and 5th day after bed rest in comparison with pre-bed rest, 15th day and 30th day during bed rest. In the combined color-direction selective response task, the P1 latencies for target ERPs on the 3rd and 30th day during bed rest were longer than on the 15th day during bed rest. As 3rd day during bed rest was in the acute adaptation period and 30th day during bed rest was in the relatively adaptation stage of head-down bed rest, the results help to clarify the effects of bed rest on different task loads and patterns of attention. It was suggested that subjects expended more time to give correct decision in the head-down tilt bed rest state. A difficulty in the recruitment of brain resources was found in feature selection task

Shielding evaluation of moving bed onion irradiator by radiometry

International Nuclear Information System (INIS)

Venkataramani, R.; Sangurdekar, P.R.; Sarangapani, R.; Raipurkar, D.R.; Mehta, S.K.; Shastri, S.P.; Patil, K.B.; Bongirwar, D.R.

1994-01-01

A moving bed onion irradiator made from m.s. cladded lead slab shields designed to hold 20 kCi of 60 Co source was evaluated by radiometry with an 8 Ci 60 Co source from CRC-2 radiography camera. Some shielding losses in the irradiator noted by radiometry could be visualized by a thermocole model of the complex shielding assembly. These were rectified by appropriate lead filling. Significant shielding losses noted at cladding layer positions of slabs were attributed to lack of interlocking features in the slabs. These had to be rectified by provision of 3 TVL of additional all round shielding supplemented by local shielding at some positions. (author). 1 fig., 1 tab

Modeling stationary and moving pebbles in a pebble bed reactor

International Nuclear Information System (INIS)

Zhao, Xiang; Montgomery, Trent; Zhang, Sijun

2015-01-01

Highlights: • The stationary and moving pebbles in a PBR are numerically studied by DEM. • The packing structure of stationary pebbles is simulated by a filling process. • The packing structural properties are obtained and analyzed. • The dynamic behavior of pebbles is predicted and discussed. - Abstract: This paper presents a numerical study of the stationary and moving pebbles in a pebble bed reactor (PBR) by means of discrete element method (DEM). The packing structure of stationary pebbles is simulated by a filling process that terminates with the settling of the pebbles into a PBR. The packing structural properties are obtained and analyzed. Subsequently, when the outlet of the PBR is opened during the operation of the PBR, the stationary pebbles start to flow downward and are removed at the bottom of the PBR. The dynamic behavior of pebbles is predicted and discussed. Our results indicate the DEM can offer both macroscopic and microscopic information for PBR design calculations and safety assessment

Simulated Moving Bed Chromatography: Separation and Recovery of Sugars and Ionic Liquid from Biomass Hydrolysates

Science.gov (United States)

Caes, Benjamin R.; Van Oosbree, Thomas R.; Lu, Fachuang; Ralph, John; Maravelias, Christos T.

2015-01-01

Simulated moving bed chromatography, a continuous separation method, enables the nearly quantitative recovery of sugar products and ionic liquid solvent from chemical hydrolysates of biomass. The ensuing sugars support microbial growth, and the residual lignin from the process is intact. PMID:23939991

Improving thermal efficiency and increasing production rate in the double moving beds thermally coupled reactors by using differential evolution (DE) technique

International Nuclear Information System (INIS)

Karimi, Mohsen; Rahimpour, Mohammad Reza; Rafiei, Razieh; Shariati, Alireza; Iranshahi, Davood

2016-01-01

Highlights: • Double moving bed thermally coupled reactor is modeled in two dimensions. • The required heat of naphtha process is attained with nitrobenzene hydrogenation. • DE optimization method is applied to optimize operating conditions. • Hydrogen, aromatic and aniline productions increase in the proposed configuration. - Abstract: According to the global requirements for energy saving and the control of global warming, multifunctional auto-thermal reactors as a novel concept in the process integration (PI) have risen up in the recent years. In the novel modification presented in this study, the required heat of endothermic naphtha reforming process has been supplied by nitrobenzene hydrogenation reaction. In addition, the enhancement of reactor performance, such as the increase of production rate, has become a key issue in the diverse industries. Thus, Differential Evolution (DE) technique is applied to optimize the operating conditions (temperature and pressure) and designing parameters of a thermally coupled reactor with double moving beds. Ultimately, the obtained results of the proposed model are compared with non-optimized and conventional model. This model results in noticeable reduction in the operational costs as well as enhancement of the net profit of the plant. The increase in the hydrogen and aromatic production shows the superiority of the proposed model.

Microbial community composition and dynamics of moving bed biofilm reactor systems treating municipal sewage.

Science.gov (United States)

Biswas, Kristi; Turner, Susan J

2012-02-01

Moving bed biofilm reactor (MBBR) systems are increasingly used for municipal and industrial wastewater treatment, yet in contrast to activated sludge (AS) systems, little is known about their constituent microbial communities. This study investigated the community composition of two municipal MBBR wastewater treatment plants (WWTPs) in Wellington, New Zealand. Monthly samples comprising biofilm and suspended biomass were collected over a 12-month period. Bacterial and archaeal community composition was determined using a full-cycle community approach, including analysis of 16S rRNA gene libraries, fluorescence in situ hybridization (FISH) and automated ribosomal intergenic spacer analysis (ARISA). Differences in microbial community structure and abundance were observed between the two WWTPs and between biofilm and suspended biomass. Biofilms from both plants were dominated by Clostridia and sulfate-reducing members of the Deltaproteobacteria (SRBs). FISH analyses indicated morphological differences in the Deltaproteobacteria detected at the two plants and also revealed distinctive clustering between SRBs and members of the Methanosarcinales, which were the only Archaea detected and were present in low abundance (<5%). Biovolume estimates of the SRBs were higher in biofilm samples from one of the WWTPs which receives both domestic and industrial waste and is influenced by seawater infiltration. The suspended communities from both plants were diverse and dominated by aerobic members of the Gammaproteobacteria and Betaproteobacteria. This study represents the first detailed analysis of microbial communities in full-scale MBBR systems and indicates that this process selects for distinctive biofilm and planktonic communities, both of which differ from those found in conventional AS systems.

Dynamic model development and validation for a nitrifying moving bed biofilter: Effect of temperature and influent load on the performance

DEFF Research Database (Denmark)

Sin, Gürkan; Weijma, Jan; Spanjers, Henri

2008-01-01

A mathematical model with adequate complexity integrating hydraulics, biofilm and microbial conversion processes is successfully developed for a continuously moving bed biofilter performing tertiary nitrification. The model was calibrated and validated using data from Nether Stowey pilot plant...... on the ammonium removal efficiency, doubling nitrification capacity every 5 degrees C increase. However, at temperatures higher than 20 degrees C, the biofilm thickness starts to decrease due to increased decay rate. The influent nitrogen load was also found to be influential on the filter performance, while...... the hydraulic loading had relatively negligible impact. Overall, the calibrated model can now reliably be used for design and process optimization purposes....

Nitrification of industrial and domestic saline wastewaters in moving bed biofilm reactor and sequencing batch reactor

International Nuclear Information System (INIS)

Bassin, Joao P.; Dezotti, Marcia; Sant'Anna, Geraldo L.

2011-01-01

Nitrification of saline wastewaters was investigated in bench-scale moving-bed biofilm reactors (MBBR). Wastewater from a chemical industry and domestic sewage, both treated by the activated sludge process, were fed to moving-bed reactors. The industrial wastewater contained 8000 mg Cl - /L and the salinity of the treated sewage was gradually increased until that level. Residual substances present in the treated industrial wastewater had a strong inhibitory effect on the nitrification process. Assays to determine inhibitory effects were performed with the industrial wastewater, which was submitted to ozonation and carbon adsorption pretreatments. The latter treatment was effective for dissolved organic carbon (DOC) removal and improved nitrification efficiency. Nitrification percentage of the treated domestic sewage was higher than 90% for all tested chloride concentrations up to 8000 mg/L. Results obtained in a sequencing batch reactor (SBR) were consistent with those attained in the MBBR systems, allowing tertiary nitrification and providing adequate conditions for adaptation of nitrifying microorganisms even under stressing and inhibitory conditions.

Nickel removal from nickel plating waste water using a biologically active moving-bed sand filter.

Science.gov (United States)

Pümpel, Thomas; Macaskie, Lynne E; Finlay, John A; Diels, Ludo; Tsezos, Marios

2003-12-01

Efficient removal of dissolved nickel was observed in a biologically active moving-bed 'MERESAFIN' sand filter treating rinsing water from an electroless nickel plating plant. Although nickel is fully soluble in this waste water, its passage through the sand filter promoted rapid removal of approximately 1 mg Ni/l. The speciation of Ni in the waste water was modelled; the most probable precipitates forming under the conditions in the filter were predicted using PHREEQC. Analyses of the Ni-containing biosludge using chemical, electron microscopical and X-ray spectroscopic techniques confirmed crystallisation of nickel phosphate as arupite (Ni3(PO4)2 x 8H2O), together with hydroxyapatite within the bacterial biofilm on the filter sand grains. Biosorption contributed less than 1% of the overall sequestered nickel. Metabolising bacteria are essential for the process; the definitive role of specific components of the mixed population is undefined but the increase in pH promoted by metabolic activity of some microbial components is likely to promote nickel desolubilisation by others.

Biodenitrification of gaseous diffusion plant aqueous wastes: stirred bed reactor

International Nuclear Information System (INIS)

Holland, M.E.

1980-01-01

Approximately 30 kilograms of nitrates per day are discarded in the raffinates (acid wastes) of the Portsmouth Gaseous Diffusion Plant's X-705 Uranium Recovery and Decontamination Facility. A biodenitrification process employing continuous-flow, stirred-bed reactors has been successfully used to remove nitrates from similar acid wastes at the Oak Ridge Y-12 Plant. Laboratory studies have been made at Portsmouth to characterize the X-705 raffinates and to test the stirred-bed biodenitrification process on such raffinates. Raffinates which had been previously characterized were pumped through continuous-flow, stirred-bed, laboratory-scale reactors. Tests were conducted over a period of 146 days and involved variations in composition, mixing requirements, and the fate of several metal ions in the raffinates. Tests results show that 20 weight percent nitrates were reduced to a target nitrate effluent concentration of 100 μg/ml with a 99.64 percent efficiency. However, the average denitrification rate achieved was only 33% of that demonstrated with the Y-12 stirred-bed system. These low rates were probably due to the toxic effects of heavy metal ions on the denitrifying bacteria. Also, most of the uranium in the raffinate feed remained in the biomass and calcite, which collected in the reactor. This could cause criticality problems. For these reasons, it was decided not to make use of the stirred-bed bioreactor at Portsmouth. Instead, the biodenitrification installation now planned will use fluidized bed columns whose performance will be the subject of a subsequent report

Adaptation to the KMT Fixed Biomass on Moving Bed process in the waste water treatment plant in Tafalla and Olite, Navarra, Spain; Adaptacion al proceso KMT de Biomasa Fija sobre Lecho Movil en la EDAR de Tafalla y Olite

Energy Technology Data Exchange (ETDEWEB)

Cortacans, J. A.; Rodrigo, J. C.; Garcia Gamuza, J.

2001-07-01

This article describes the remodeling carried out on the Tafalla and Olite waste water treatment plant in 2000to enable it to cope with a larger flow and load without having to construct new treatment lines. This was made possible by adapting the existing conventional active sludge process to the KMT Fixed Biomass on Moving Bed process. The article also shows how the final two-stage design was verified by means of pilot plant trials. These experiments tested the technical viability of installing a first high-load reactor prior to the existing primary decantation as a way of dealing with the seasonal effluents from the wine-cellars in the region and of obtaining partial nitrification in the last biological tank of the second stage during the rest of the year. (Author) 7 refs.

Biomass Torrefaction Process Review and Moving Bed Torrefaction System Model Development

Energy Technology Data Exchange (ETDEWEB)

Jaya Shakar Tumuluru; Shahab Sokhansanj; Christopher T. Wright; Richard D. Boardman

2010-08-01

Torrefaction is currently developing as an important preprocessing step to improve the quality of biomass in terms of physical properties, and proximate and ultimate composition. Torrefaction is a slow heating of biomass in an inert or reduced environment to a maximum temperature of 300 C. Torrefaction can also be defined as a group of products resulting from the partially controlled and isothermal pyrolysis of biomass occurring in a temperature range of 200-230 C and 270-280 C. Thus, the process can also be called a mild pyrolysis as it occurs at the lower temperature range of the pyrolysis process. At the end of the torrefaction process, a solid uniform product with lower moisture content and higher energy content than raw biomass is produced. Most of the smoke-producing compounds and other volatiles are removed during torrefaction, producing a final product that will have a lower mass but a higher heating value. An important aspect of research is to establish a degree of torrefaction where gains in heating value offset the loss of mass. There is a lack of literature on torrefaction reactor designs and a design sheet for estimating the dimensions of the torrefier based on capacity. This study includes (a) conducting a detailed review on the torrefaction of biomass in terms of understanding the process, product properties, off-gas compositions, and methods used, and (b) to design a moving bed torrefier, taking into account the basic fundamental heat and mass transfer calculations. Specific objectives include calculating the dimensions like diameter and height of the moving packed bed for different capacities, designing the heat loads and gas flow rates, and developing an interactive excel sheet where the user can define design specifications. In this report, 25-1000 kg/hr are used in equations for the design of the torrefier, examples of calculations, and specifications for the torrefier.

Kinetic Modeling of Synthetic Wastewater Treatment by the Moving-bed Sequential Continuous-inflow Reactor (MSCR

Directory of Open Access Journals (Sweden)

Mohammadreza Khani

2016-11-01

Full Text Available It was the objective of the present study to conduct a kinetic modeling of a Moving-bed Sequential Continuous-inflow Reactor (MSCR and to develop its best prediction model. For this purpose, a MSCR consisting of an aerobic-anoxic pilot 50 l in volume and an anaerobic pilot of 20 l were prepared. The MSCR was fed a variety of organic loads and operated at different hydraulic retention times (HRT using synthetic wastewater at input COD concentrations of 300 to 1000 mg/L with HRTs of 2 to 5 h. Based on the results and the best system operation conditions, the highest COD removal (98.6% was obtained at COD=500 mg/L. The three well-known first order, second order, and Stover-Kincannon models were utilized for the kinetic modeling of the reactor. Based on the kinetic analysis of organic removal, the Stover-Kincannon model was chosen for the kinetic modeling of the moving bed biofilm. Given its advantageous properties in the statisfactory prediction of organic removal at different organic loads, this model is recommended for the design and operation of MSCR systems.

Model-based design of a pilot-scale simulated moving bed for purification of citric acid from fermentation broth.

Science.gov (United States)

Wu, Jinglan; Peng, Qijun; Arlt, Wolfgang; Minceva, Mirjana

2009-12-11

One of the conventional processes used for the recovery of citric acid from its fermentation broth is environmentally harmful and cost intensive. In this work an innovative benign process, which comprises simulated moving bed (SMB) technology and use of a tailor-made tertiary poly(4-vinylpyridine) (PVP) resin as a stationary phase is proposed. This paper focuses on a model-based design of the operation conditions for an existing pilot-scale SMB plant. The SMB unit is modeled on the basis of experimentally determined hydrodynamics, thermodynamics and mass transfer characteristics in a single chromatographic column. Three mathematical models are applied and validated for the prediction of the experimentally attained breakthrough and elution profiles of citric acid and the main impurity component (glucose). The transport dispersive model was selected for the SMB simulation and design studies, since it gives a satisfactory prediction of the elution profiles within acceptable computational time. The equivalent true moving bed (TMB) and SMB models give a good prediction of the experimentally attained SMB separation performances, obtained with a real clarified and concentrated fermentation broth as a feed mixture. The SMB separation requirements are set to at least 99.8% citric acid purity and 90% citric acid recovery in the extract stream. The complete regeneration in sections 1 and 4 is unnecessary. Therefore the net flow rates in all four SMB sections have been considered in the unit design. The influences of the operating conditions (the flow rate in each section, switching time and unit configuration) on the SMB performances were investigated systematically. The resulting SMB design provides 99.8% citric acid purity and 97.2% citric acid recovery in the extract. In addition the citric acid concentration in the extract is a half of its concentration in the pretreated fermentation broth (feed).

Bed care for patients in palliative settings: considering risks to caregivers and bed surfaces.

Science.gov (United States)

Fragala, Guy

2015-02-01

Ensuring patients are comfortable in bed is key to effective palliative care, but when moving and positioning patients in bed, health professionals face an occupational risk of injury. The turning and positioning (TAP) system is a new method of moving patients in bed, that evidence has shown to reduce the risk of injury to caregivers. Providing the correct bed surface is another aspect of bed care essential to the comfort of the palliative patient, and to aid wound prevention and treatment. It is important to take a patient-centred approach when considering the most appropriate bed surface patients. This article provides an overview and discussion of these two aspects of bed care for palliative patients.

System for the Reduction of Substances in Reject Water from Reed-Bed Sludge Mineralization Plants

DEFF Research Database (Denmark)

2004-01-01

The invention is a system for the reduction of substances in reject water from reed-bed sludge mineralization plants (also referred to as sludge dewatering reed-beds). The systems utilizes the composition of substances in reject water from reed-beds and that of sludge to reduce substance mass from...... the reject water via recirculation into a mixed reactor and back onto the reed-beds. The mixed rector consists of a container in which sludge (that is typically loaded directly on to reed-beds) is mixed with recirculated reject water from reed-beds. The sludge mixture has a definable hydraulic retention time...... of by sending it back to the head of a wastewater treatment plant. The system has proven to reduce the mass of nitrogen, COD, and water in the reject water, and can possibly reduce phosphorus and other substances. The overall effect is a reduction in the substance recycle within a wastewater treatment plant...

Multi-objective optimization for the economic production of d-psicose using simulated moving bed chromatography.

Science.gov (United States)

Wagner, N; Håkansson, E; Wahler, S; Panke, S; Bechtold, M

2015-06-12

The biocatalytic production of rare carbohydrates from available sugar sources rapidly gains interest as a route to acquire industrial amounts of rare sugars for food and fine chemical applications. Here we present a multi-objective optimization procedure for a simulated moving bed (SMB) process for the production of the rare sugar d-psicose from enzymatically produced mixtures with its epimer d-fructose. First, model parameters were determined using the inverse method and experimentally validated on a 2-2-2-2 lab-scale SMB plant. The obtained experimental purities (PUs) were in excellent agreement with the simulated data derived from a transport-dispersive true-moving bed model demonstrating the feasibility of the proposed design. In the second part the performance of the separation was investigated in a multi-objective optimization study addressing the cost-contributing performance parameters productivity (PR) and desorbent requirement (DR) as a function of temperature. While rare sugar SMB operation under conditions of low desorbent consumption was found to be widely unaffected by temperature, SMB operation focusing on increased PR significantly benefited from high temperatures, with possible productivities increasing from 3.4kg(Lday)(-1) at 20°C to 5kg(Lday)(-1) at 70°C, indicating that decreased selectivity at higher temperatures could be fully compensated for by the higher mass transfer rates, as they translate into reduced switch times and hence higher PR. A DR/PR Pareto optimization suggested a similar but even more pronounced trend also under relaxed PU requirements, with the PR increasing from 4.3kg(Lday)(-1) to a maximum of 7.8kg(Lday)(-1) for SMB operation at 50°C when the PU of the non-product stream was reduced from 99.5% to 90%. Based on the in silico optimization results experimental SMB runs were performed yielding considerable PRs of 1.9 (30°C), 2.4 (50°C) and 2.6kg(Lday)(-1) (70°C) with rather low DR (27L per kg of rare sugar produced) on a

Sludge granulation in an UASB-moving bed biofilm hybrid reactor for efficient organic matter removal and nitrogen removal in biofilm reactor.

Science.gov (United States)

Chatterjee, Pritha; Ghangrekar, M M; Rao, Surampalli

2018-02-01

A hybrid upflow anaerobic sludge blanket (UASB)-moving bed biofilm (MBB) and rope bed biofilm (RBB) reactor was designed for treatment of sewage. Possibility of enhancing granulation in an UASB reactor using moving media to improve sludge retention was explored while treating low-strength wastewater. The presence of moving media in the top portion of the UASB reactor allowed a high solid retention time even at very short hydraulic retention times and helped in maintaining selection pressure in the sludge bed to promote formation of different sized sludge granules with an average settling velocity of 67 m/h. These granules were also found to contain plenty of extracellular polymeric substance (EPS) such as 58 mg of polysaccharides (PS) per gram of volatile suspended solids (VSS) and protein (PN) content of 37 mg/g VSS. Enriched sludge of nitrogen-removing bacteria forming a porous biofilm on the media in RBB was also observed in a concentration of around 894 g/m 2 . The nitrogen removing sludge also had a high EPS content of around 22 mg PS/g VSS and 28 mg PN/g VSS. This hybrid UASB-MBB-RBB reactor with enhanced anaerobic granular sludge treating both carbonaceous and nitrogenous matter may be a sustainable solution for decentralized sewage treatment.

Moving Plants / Planter i Bevægelse

DEFF Research Database (Denmark)

as a focal point for making local and global connections between aesthetic engagements with contemporary ecological issues and practices of concern. This book is a companion piece to the namesake art exhibition, bringing together the exhibited artists with scholars centrally invested in similar plant...... are increasingly insisting that plants are amongst our most important earthly co-inhabitants if we are to thrive and survive in a climatically changing world. As an exhibition, Moving Plants showcases art practices from across the world regions of East Asia and Europe that all centre, one way or another, on plants...

Biomass Torrefaction Process Review and Moving Bed Torrefaction System Model Development

Energy Technology Data Exchange (ETDEWEB)

Jaya Shakar Tumuluru; Shahab Sokhansanj; Christopher T. Wright

2010-08-01

Torrefaction is currently developing as an important preprocessing step to improve the quality of biomass in terms of physical properties, and proximate and ultimate composition. Torrefaction is a slow heating of biomass in an inert or reduced environment to a maximum temperature of 300°C. Torrefaction can also be defined as a group of products resulting from the partially controlled and isothermal pyrolysis of biomass occurring in a temperature range of 200–230ºC and 270–280ºC. Thus, the process can also be called a mild pyrolysis as it occurs at the lower temperature range of the pyrolysis process. At the end of the torrefaction process, a solid uniform product with lower moisture content and higher energy content than raw biomass is produced. Most of the smoke-producing compounds and other volatiles are removed during torrefaction, producing a final product that will have a lower mass but a higher heating value. An important aspect of research is to establish a degree of torrefaction where gains in heating value offset the loss of mass. There is a lack of literature on torrefaction reactor designs and a design sheet for estimating the dimensions of the torrefier based on capacity. This study includes a) conducting a detailed review on the torrefaction of biomass in terms of understanding the process, product properties, off-gas compositions, and methods used, and b) to design a moving bed torrefier, taking into account the basic fundamental heat and mass transfer calculations. Specific objectives include calculating the dimensions like diameter and height of the moving packed bed for different capacities, designing the heat loads and gas flow rates, and developing an interactive excel sheet where the user can define design specifications. In this report, 25–1000 kg/hr are used in equations for the design of the torrefier, examples of calculations, and specifications for the torrefier.

An Evaluation of Reed Bed Technology to Dewater Army Wastewater Treatment Plant Sludge

Science.gov (United States)

1993-09-01

speculated that the plants produced "root exudations" that were active against pathogens , and that the plants specifically showed an affinity for cadmium, zinc...mineralize and for pathogens to be destroyed. This downtime makes multiple beds necessary. The USEPA also reports that the major advantage of the reed...employee to regulate the sludge applications. This employee would also visually assess the beds for possible problems such as weed or insect ( aphid

Technical, hygiene, economic, and life cycle assessment of full-scale moving bed biofilm reactors for wastewater treatment in India.

Science.gov (United States)

Singh, Anju; Kamble, Sheetal Jaisingh; Sawant, Megha; Chakravarthy, Yogita; Kazmi, Absar; Aymerich, Enrique; Starkl, Markus; Ghangrekar, Makarand; Philip, Ligy

2018-01-01

Moving bed biofilm reactor (MBBR) is a highly effective biological treatment process applied to treat both urban and industrial wastewaters in developing countries. The present study investigated the technical performance of ten full-scale MBBR systems located across India. The biochemical oxygen demand, chemical oxygen demand, total suspended solid, pathogens, and nutrient removal efficiencies were low as compared to the values claimed in literature. Plant 1 was considered for evaluation of environmental impacts using life cycle assessment approach. CML 2 baseline 2000 methodology was adopted, in which 11 impact categories were considered. The life cycle impact assessment results revealed that the main environmental hot spot of this system was energy consumption. Additionally, two scenarios were compared: scenario 1 (direct discharge of treated effluent, i.e., no reuse) and scenario 2 (effluent reuse and tap water replacement). The results showed that scenario 2 significantly reduce the environmental impact in all the categories ultimately decreasing the environmental burden. Moreover, significant economic and environmental benefits can be obtained in scenario 2 by replacing the freshwater demand for non-potable uses. To enhance the performance of wastewater treatment plant (WWTP), there is a need to optimize energy consumption and increase wastewater collection efficiency to maximize the operating capacity of plant and minimize overall environmental footprint. It was concluded that MBBR can be a good alternative for upgrading and optimizing existing municipal wastewater treatment plants with appropriate tertiary treatment. Graphical abstract ᅟ.

Rocky Flats Plant fluidized-bed incinerator

International Nuclear Information System (INIS)

Meile, L.J.; Meyer, F.G.; Johnson, A.J.; Ziegler, D.L.

1982-01-01

Laboratory and pilot-scale testing of a fluidized-bed incineration process for radioactive wastes led to the installation of an 82-kg/hr demonstration unit at Rocky Flats Plant in 1978. Design philosophy and criteria were formulated to fulfill the needs and objectives of an improved radwaste-incineration system. Unique process concepts include low-temperature (550 0 C), flameless, fluidized-bed combustion and catalytic afterburning; in-situ neutralization of acid gases; and dry off-gas cleanup. Detailed descriptions of the process and equipment are presented along with a summary of the equipment and process performance during a 2-1/2 year operational-testing period. Equipment modifications made during the test period are described. Operating personnel requirements for solid-waste burning are shown to be greater than those required for liquid-waste incineration; differences are discussed. Process-utility and raw-materials consumption rates for full-capacity operation are presented and explained. Improvements in equipment and operating procedures are recommended for any future installations. Process flow diagrams, an area floor plan, a process-control-system schematic, and equipment sketches are included

Technical notes for the conceptual design for an atmospheric fluidized-bed direct combustion power generating plant. [570 MWe plant

Energy Technology Data Exchange (ETDEWEB)

None

1978-04-01

The design, arrangement, thermodynamics, and economics of a 592 MW(e) (nominal gross) electric power generating plant equipped with a Babcock and Wilcox Company (B and W) atmospheric fluidized bed (AFB) boiler are described. Information is included on capital and operating costs, process systems, electrical systems, control and instrumentation, and environmental systems. This document represents a portion of an overall report describing the conceptual designs of two atmospheric fluidized bed boilers and balance of plants for the generation of electric power and the analysis and comparison of these conceptual designs to a conventional pulverized coal-fired electric power generation plant equipped with a wet limestone flue gas desulfurization system.

Technical notes for the conceptual design for an atmospheric fluidized-bed direct combustion power generating plant. [570 MWe plant

Energy Technology Data Exchange (ETDEWEB)

None

1978-04-01

The design, arrangement, thermodynamics, and economics of a 578 MW(e) (nominal gross) electric power generating plant equipped with a Foster Wheeler Energy Corporation (FWEC) atmospheric fluidized bed (AFB) boiler are described. Information is included on capital and operating costs, process systems, electrical systems, control and instrumentation, and environmental systems. This document represents a portion of an overall report describing the conceptual designs of two atmospheric fluidized bed boilers and balance of plants for the generation of electric power and the analysis and comparison of these conceptual designs to a conventional pulverized coal-fired electric power generation plant equipped with a wet limestone flue gas desulfurization system.

Review on Biomass Torrefaction Process and Product Properties and Design of Moving Bed Torrefaction System Model Development

Energy Technology Data Exchange (ETDEWEB)

Jaya Shankar Tumuluru; Christopher T. Wright; Shahab Sokhansanj

2011-08-01

A Review on Torrefaction Process and Design of Moving Bed Torrefaction System for Biomass Processing Jaya Shankar Tumuluru1, Shahab Sokhansanj2 and Christopher T. Wright1 Idaho National Laboratory Biofuels and Renewable Energy Technologies Department Idaho Falls, Idaho 83415 Oak Ridge National Laboratory Bioenergy Resource and Engineering Systems Group Oak Ridge, TN 37831 Abstract Torrefaction is currently developing as an important preprocessing step to improve the quality of biomass in terms of physical properties, and proximate and ultimate composition. Torrefaction is a slow heating of biomass in an inert or reduced environment to a maximum temperature of 300 C. Torrefaction can also be defined as a group of products resulting from the partially controlled and isothermal pyrolysis of biomass occurring in a temperature range of 200-230 C and 270-280 C. Thus, the process can also be called a mild pyrolysis as it occurs at the lower temperature range of the pyrolysis process. At the end of the torrefaction process, a solid uniform product with lower moisture content and higher energy content than raw biomass is produced. Most of the smoke-producing compounds and other volatiles are removed during torrefaction, which produces a final product that will have a lower mass but a higher heating value. There is a lack of literature on the design aspects of torrefaction reactor and a design sheet for estimating the dimensions of the torrefier based on capacity. This study includes (a) conducting a detailed review on the torrefaction of biomass in terms of understanding the process, product properties, off-gas compositions, and methods used, and (b) to design a moving bed torrefier, taking into account the basic fundamental heat and mass transfer calculations. Specific objectives include calculating the dimensions like diameter and height of the moving packed bed torrefier for different capacities ranging from 25-1000 kg/hr, designing the heat loads and gas flow rates, and

Controlled biomass formation and kinetics of toluene degradation in a bioscrubber and in a reactor with a periodically moved trickle-bed.

Science.gov (United States)

Wübker, S M; Laurenzis, A; Werner, U; Friedrich, C

1997-08-20

The kinetics of degradation of toluene from a model waste gas and of biomass formation were examined in a bioscrubber operated under different nutrient limitations with a mixed culture. The applicability of the kinetics of continuous cultivation of the mixed culture was examined for a special trickle-bed reactor with a periodically moved filter bed. The efficiency of toluene elimination of the bioscrubber was 50 to 57% and depended on the toluene mass transfer as evident from a constant productivity of 0.026 g dry cell weight/L . h over the dilution rate. Under potassium limitation the biomass productivity was reduced by 60% to 0.011 g dry cell weight/L . h at a dilution rate of 0.013/h. Conversely, at low dilution rates the specific toluene degradation rates increased. Excess biomass in a trickle-bed reactor causes reduction of interfacial area and mass transfer, and increase in pressure drop. To avoid these disadvantages, the trickle-bed was moved periodically and biomass was removed with outflowing medium. The concentration of steady state biomass fixed on polyamide beads decreased hyperbolically with the dilution rate. Also, the efficiency of toluene degradation decreased from 72 to 56% with increasing dilution rate while the productivity increased. Potassium limitation generally caused a reduction in biomass, productivity, and yield while the specific degradation increased with dilution rate. This allowed the application of the principles of the chemostat to the trickle-bed reactor described here, for toluene degradation from waste gases. (c) 1997 John Wiley & Sons, Inc. Biotechnol Bioeng 55: 686-692, 1997.

Bubbling fluidized bed boiler for Vanaja power plant

Energy Technology Data Exchange (ETDEWEB)

Sormunen, R.; Haermae, P.; Vessonen, K.; Ketomaeki, A. [ed.

1998-07-01

At the Vanaja Power Plant, on the outskirts of Haemeenlinna, there have been changes which reflect the central goals in IVO`s product development work. At Vanaja, efficiency is combined with environmental friendliness. In the early 1980s, the plant was modernized to produce district heat in addition to electricity. At that time, along with the new gas turbine at the plant, the main fuel, coal, while remaining the fuel for the old boilers, was replaced by natural gas. This year a new type of bubbling fluidized bed boiler enabling continuous use of peat and trial use of biofuels along with coal was introduced at the plant. In addition to the Nordic countries, this kind of technology is required in central eastern Europe, where modernization of ageing power plants is being planned to achieve the best possible solutions in respect of production and the environment. IVO develops a new repair technique for underwater sites

A multi-biofuel, fluidised-bed district heating plant in Sweden

International Nuclear Information System (INIS)

Anon.

1996-01-01

At the end of 1984, the city of Haessleholm in Sweden started up a 65 MW district heating plant which included a 14 MW solid fuel plant. The plant included a specially-designed fluidised-bed boiler, capable of burning all grades of solid fuel, including organic fuel of such low grade that no other boilers around Haessleholm could use it. By 1992, the district heating system served some 250 detached houses and 6,000 flats as well as several schools and industrial premises. The biofuel boiler provides almost 60% of the energy required. (UK)

7 CFR 330.201 - Applications for permits to move plant pests.

Science.gov (United States)

2010-01-01

... 7 Agriculture 5 2010-01-01 2010-01-01 false Applications for permits to move plant pests. 330.201... HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE FEDERAL PLANT PEST REGULATIONS; GENERAL; PLANT PESTS; SOIL, STONE, AND QUARRY PRODUCTS; GARBAGE Movement of Plant Pests § 330.201 Applications for permits to...

Design and assembling of a moving bed column to operate with ion exchange resin

International Nuclear Information System (INIS)

Franca Junior, J.M.; Abrao, A.

1976-01-01

A new moving bed column specially designed to operate with ion exchange resins in such peculiar situations where there is gas evolution is reported. The second part reports the use of the column in the preparation of nuclear grade ammonium uranyl tricarbonate (AUTC), from crude uranyl nitrate solution. Uranium-VI is binded into a strong cationic ion exchanger and then eluted with (NH 4 ) 2 CO 3 . The final product is crystallized from the eluate by simply cooling down the temperature to 5 0 or by addition of ethanol. Loading of resin with uranyl ion, its elution with ammonium carbonate and the crystallization of AUTC is described [pt

Bed Bugs and Schools

Science.gov (United States)

Bed bugs have long been a pest – feeding on blood, causing itchy bites and generally irritating their human hosts. They are successful hitchhikers, and can move from an infested site to furniture, bedding, baggage, boxes, and clothing.

FY 1996 report on the results of the development of an entrained bed coal gasification power plant. Part 2. Investigational study of verification plant; 1995 nendo seika hokokusho. Funryusho sekitan gaska hatsuden plant kaihatsu - Sono 2. Jissho plant ni kansuru chosa kenkyu hen

Energy Technology Data Exchange (ETDEWEB)

NONE

1997-01-01

For the purpose of developing the technology of the integrated coal gasification combined cycle power generation, an investigational study of verification plant was made, and the FY 1996 results were summarized. In this fiscal year, the conceptual design was made of the Nakoso method based on the method of Nakoso pilot plant, the fixed bed method in which fixed bed gas refining facilities tested in Nakoso pilot plant were adopted, and the packed bed method. In the Nakoso method, 5 cases were studied using the air blown two-stage entrained bed for gasifier, dry two-stage fluidized bed for desulfurization and dry granular bed packed bed for dust removal. In the fixed bed method, 2 cases were studied using the air blown two-stage entrained bed for gasifier and dry fixed bed for gas refining. In the packed bed method, 2 cases were studied using the air blown two-stage entrained bed for gasifier and dry packed bed for gas refining. As to gas turbine facilities, 5 cases were studied in which GT output is 115MW - 215MW (output of combined cycle power generation: 220MW - 420MW). (NEDO)

Pressurized fluidized bed combustion combined cycle power plant with coal gasification: Second generation pilot plant

International Nuclear Information System (INIS)

Farina, G.L.; Bressan, L.

1991-01-01

This paper presents the technical and economical background of a research and development program of a novel power generation scheme, which is based on coal gasification, pressurized fluid bed combustion and combined cycles. The participants in this program are: Foster Wheeler (project leader), Westinghouse, IGT and the USA Dept. of Energy. The paper describes the characteristics of the plant, the research program in course of implementation, the components of the pilot plant and the first results obtained

Conceptual designs of pressurized fluidized bed and pulverized coal fired power plants

International Nuclear Information System (INIS)

Doss, H.S.; Bezella, W.A.; Hamm, J.R.; Pietruszkiewicz, J.

1984-01-01

This paper presents the major technical and economic characteristics of steam and air-cooled pressurized fluidized bed (PFB) power plant concepts, along with the characteristics of a pulverized coal fired power plant equipped with an adipic acid enhanced wet-limestone flue gas desulfurization system. Conceptual designs for the three plants were prepared to satisfy a set of common groundrules developed for the study. Grassroots plants, located on a generic plant site were assumed. The designs incorporate technologies projected to be commercial in the 1990 time frame. Power outputs, heat rates, and costs are presented

Production of camu camu plants with different organic substrates in conventional nursery bed

Directory of Open Access Journals (Sweden)

Carlos Abanto Rodriguez

2013-12-01

Full Text Available The aim was to verify the initial development of camu camu plants with different organic substrates in conventional nursery bedding microsprinkler irrigation and shade management Chromatine® mesh with 50% red light. We used genetic material from mother plants Germplasm Bank of INIA-camu camu Iquitos, seeds were germinated in decomposed sawdust and kept for a period of 40 days after subculturing was performed with 10 cm in height in different substrates according treatments in nursery beds with dimensions of 1.20 m wide x 10 m long with a depth of 30 cm. After conducting assessments of height (cm and basal diameter (mm for a period of 120 days, it was found that the substrate manure has become the substrate for greater efficiency in plant development camu camu substrate followed by humus worm.

Pilot plant of continuous ion-exchange in fluidized bed

International Nuclear Information System (INIS)

Botella, T.; Otero de Becerra, J.; Gasos, P.

1985-01-01

Research and development on continuous ion-exchange processes has been a major item in hydrometallurgy. This new technology has been under development during the last 15 years in the leading countries at uranium hydrometallurgy. The fluidized bed multi-stage column technique is proven to be the most attractive one, and since 1977 several commercial plants have begun production, some of them with a throughput of 500 cubic meters of pregnant liquour per hour. J.E.N. undertook the study of this new technology for uranium recovery in the early 70's. In 1979 a pilot plant had been installed, based on previous laboratory and smaller pilot plant experience. The plant was designed following JEN's own technology and has been operating successfully at a flow rate of near 0.5 cubic meters per hour. The test runs and the main processing, engineering and operation features are described. At present a demonstation plant is under design, and this installation will provide the necessary know-how for the construction and operation of a commercial scale plant. (author)

The Safety of Hospital Beds: Ingress, Egress, and In-Bed Mobility.

Science.gov (United States)

Morse, Janice M; Gervais, Pierre; Pooler, Charlotte; Merryweather, Andrew; Doig, Alexa K; Bloswick, Donald

2015-01-01

To explore the safety of the standard and the low hospital bed, we report on a microanalysis of 15 patients' ability to ingress, move about the bed, and egress. The 15 participants were purposefully selected with various disabilities. Bed conditions were randomized with side rails up or down and one low bed with side rails down. We explored the patients' use of the side rails, bed height, ability to lift their legs onto the mattress, and ability to turn, egress, and walk back to the chair. The standard bed was too high for some participants, both for ingress and egress. Side rails were used by most participants when entering, turning in bed, and exiting. We recommend that side rails be reconsidered as a means to facilitate in-bed movement, ingress, and egress. Furthermore, single deck height settings for all patients are not optimal. Low beds as a safety measure must be re-evaluated.

A novel approach for harnessing biofilm communities in moving bed biofilm reactors for industrial wastewater treatment

Directory of Open Access Journals (Sweden)

Joe A. Lemire

2015-10-01

Full Text Available Moving bed biofilm reactors (MBBRs are an effective biotechnology for treating industrial wastewater. Biomass retention on moving bed biofilm reactor (MBBR carriers (biofilm support materials, allows for the ease-of-operation and high treatment capacity of MBBR systems. Optimization of MBBR systems has largely focused on aspects of carrier design, while little attention has been paid to enhancing strategies for harnessing microbial biomass. Previously, our research group demonstrated that mixed-species biofilms can be harvested from an industrial wastewater inoculum [oil sands process water (OSPW] using the Calgary Biofilm Device (CBD. Moreover, the resultant biofilm communities had the capacity to degrade organic toxins (naphthenic acids—NAs that are found in OSPW. Therefore, we hypothesized that harnessing microbial communities from industrial wastewater, as biofilms, on MBBR carriers may be an effective method to bioremediate industrial wastewater.Here, we detail our methodology adapting the workflow employed for using the CBD, to generate inoculant carriers to seed an MBBR.In this study, OSPW-derived biofilm communities were successfully grown, and their efficacy evaluated, on commercially available MBBR carriers affixed within a modified CBD system. The resultant biofilms demonstrated the capacity to transfer biomass to recipient carriers within a scaled MBBR. Moreover, MBBR systems inoculated in this manner were fully active 2 days post-inoculation, and readily degraded a select population of NAs. Together, these findings suggest that harnessing microbial communities on carriers affixed within a modified CBD system may represent a facile and rapid method for obtaining functional inoculants for use in wastewater MBBR treatment systems.

Development of a computer program for the simulation of one-dimensional fixed- and moving-bed reactors

International Nuclear Information System (INIS)

Hartner, P.

1996-11-01

Chemical reactors with a flow through a bed of solid particles are of great importance in the processing industry. Modern computational tools allow for an improved characterization of the complex facts in such reactors leading to new opportunities of optimizing the reactor operation and environmental effects. This thesis is concerned with the development of the one-dimensional simulation software REASIM. The program covers the effects within a reacting bed and is designed for fixed and moving beds. To describe the reactor the balances for energy, momentum and mass are solved. The drying of the particles, pyrolysis and chemical gas-solid and gas-gas reactions are considered. For the description of the chemical gas-solid reactions a particle model for porous solids is developed. The calculation of mass transfer and of chemical reactions is strictly separated. All parameters necessary for the model can be measured in the laboratory. The model equations form a system of partial differential equations. This system is transformed to a set of ordinary differential equations. It is found that the best discretization method is the method of finite differences with the upwind-scheme for situations where convection is strong. The program has a modular structure making it is easy to replace parts of the program by new, improved modules if they become available. (author)

Development of Open Test-bed for Autonomous Operation in Nuclear Power Plants

International Nuclear Information System (INIS)

Kim, Seungmin; Heo, Gyunyoung

2017-01-01

Nuclear power plants also recognize the need for automation. However, it is dangerous technology to have a significant impact on human society. In addition, due to the uncertain legal responsibility for autonomous operation, the application and development speed of nuclear energy related automation technology will be significantly decrease compared to other industries. It is argued that the application of AI and automation technology to power plants should not be prematurely applied or not based on the principle of applying proven technology since nuclear power plants are the highest level security operated facilities. As described above, the overall algorithm of the Test Bed is an autonomous operation algorithm (rulebased algorithm, learning-based algorithm, semiautonomous operation algorithm) to judge the entry condition of the procedure through condition monitoring and to enter the appropriate operating procedure. In order to make a test bed, the investigation for the heuristic part of the existing procedures and the heuristic part from the circumstance which is not specified in the procedure is needed. In the learning based and semi-autonomous operation algorithms, using MARS to extract its operating data and operational logs and try out various diagnostic algorithms as described above. Through the completion of these future tasks, the test bed which can compared with actual operators will be constructed and that it will be able to check its effectiveness by improving competitively with other research teams through the characteristics of shared platform.

Pengolahan Lindi Menggunakan Moving Bed Biofilm Reactor dengan Proses Anaerobik-Aerobik-Anoksik

Directory of Open Access Journals (Sweden)

Nuriflalail Rio Jusepa

2017-01-01

Full Text Available Lindi mengandung konsentrasi organik, Total Kjeldahl Nitrogen, amonium, nitrit dan nitrat yang tinggi sehingga lindi yang tidak diolah dapat mencemari lingkungan. Pengolahan biologis dengan sistem fluidized attached growth seperti Moving Bed Biofilm Reactor (MBBR dapat digunakan untuk menurunkan senyawa organik dan senyawa nitrogen. Konsentrasi organik dan nitrogen yang tinggi pada lindi dapat diolah dengan mengatur proses aerobik-anaerobik-anoksik di dalam MBBR. Kapasitas pengolahan MBBR yang digunakan sebesar 10 L dan media Kaldness (K1 sebanyak 2 L. MBBR dioperasikan dengan sistem batch, dengan kondisi aerobik yang berasal dari aerator dan pompa submersible, kondisi anaerobik berasal dari pompa submersible saja, dan kondisi anoksik yang berasal dari pompa submersible dan aerator. Hasil penelitian ini menunjukkan bahwa MBBR dapat digunakan untuk menurunkan senyawa nitrogen dan senyawa organik. Efisiensi penyisihan optimum senyawa organik sebesar 87% pada proses anaerobik baik pada sistem fluidized attached growth maupun suspended growth. Efisiensi penyisihan optimum senyawa nitrogen sebesar 72% pada proses anoksik baik pada sistem fluidized attached growth maupun suspended growth.

Hypothetical operation model for the multi-bed system of the Tritium plant based on the scheduling approach

Energy Technology Data Exchange (ETDEWEB)

Lee, Jae-Uk, E-mail: eslee@dongguk.edu [Department of Chemical Engineering, Pohang University of Science and Technology, San 31, Hyoja-Dong, Pohang 790-784 (Korea, Republic of); Chang, Min Ho; Yun, Sei-Hun [National Fusion Research Institute, 169-148-gil Kwahak-ro, Yusong-gu, Daejon 34133 (Korea, Republic of); Lee, Euy Soo [Department of Chemical & Biochemical Engineering, Dongguk University, Seoul 100-715 (Korea, Republic of); Lee, In-Beum [Department of Chemical Engineering and Graduate School of Engineering Mastership, Pohang University of Science and Technology, San 31, Hyoja-Dong, Pohang 790-784 (Korea, Republic of); Lee, Kun-Hong [Department of Chemical Engineering, Pohang University of Science and Technology, San 31, Hyoja-Dong, Pohang 790-784 (Korea, Republic of)

2016-11-01

Highlights: • We introduce a mathematical model for the multi-bed storage system in the tritium plant. • We obtain details of operation by solving the model. • The model assesses diverse operation scenarios with respect to risk. - Abstract: In this paper, we describe our hypothetical operation model (HOM) for the multi-bed system of the storage and delivery system (SDS) of the ITER tritium plant. The multi-bed system consists of multiple getter beds (i.e., for batch operation) and buffer vessels (i.e., for continuous operation). Our newly developed HOM is formulated as a mixed-integer linear programming (MILP) model and has been extensively investigated to optimize chemical and petrochemical production planning and scheduling. Our model determines the timing, duration, and size of tasks corresponding to each set of equipment. Further, inventory levels for each set of equipment are calculated. Our proposed model considers the operation of one cycle of one set of getter beds and is implemented and assessed as a case study problem.

Gas Reactor International Cooperative program. Pebble bed reactor plant: screening evaluation. Volume 2. Conceptual balance of plant design

Energy Technology Data Exchange (ETDEWEB)

1979-11-01

This report consists of three volumes which describe the design concepts and screening evaluation for a 3000 MW(t) Pebble Bed Reactor Multiplex Plant (PBR-MX). The Multiplex plant produces both electricity and transportable chemical energy via the thermochemical pipeline (TCP). The evaluation was limited to a direct cycle plant which has the steam generators and steam reformers in the primary circuit. This volume describes the conceptual balance-of-plant (BOP) design and was prepared by United Engineers and Constructors, Inc. of Philadelphia, Pennsylvania. The major emphasis of the BOP study was a preliminary design of an overall plant to provide a basis for future studies.

Gas Reactor International Cooperative program. Pebble bed reactor plant: screening evaluation. Volume 2. Conceptual balance of plant design

International Nuclear Information System (INIS)

1979-11-01

This report consists of three volumes which describe the design concepts and screening evaluation for a 3000 MW(t) Pebble Bed Reactor Multiplex Plant (PBR-MX). The Multiplex plant produces both electricity and transportable chemical energy via the thermochemical pipeline (TCP). The evaluation was limited to a direct cycle plant which has the steam generators and steam reformers in the primary circuit. This volume describes the conceptual balance-of-plant (BOP) design and was prepared by United Engineers and Constructors, Inc. of Philadelphia, Pennsylvania. The major emphasis of the BOP study was a preliminary design of an overall plant to provide a basis for future studies

An introduction to constructed wetlands (reed beds) sustainable low cost wastewater treatment plants

International Nuclear Information System (INIS)

Ahmad, M.I.

2005-01-01

The use of 'conventional' wastewater treatment technology (trickling filters and activated sludge) in developing countries has often been unsuccessful due to high cost, complex operating requirements and expensive maintenance procedures. Typical examples of such projects are wastewater plants in Islamabad and Karachi. Actually the conventional systems, such as trickling filters and activated sludge plants were developed to address the concerns about organic pollution of natural water bodies in western temperate climates, rather than the reduction of organic matter as well as pathogens which is often a priority in developing countries. Pakistan, being a developing country cannot and should not follow the western technology blindly but needs the use of a ppropriate technology . Appropriate technology is defined as a treatment system which meets the following criteria: Affordable: Total amount costs, including capital, operation, maintenance and depreciation are within the user's ability to pay. Operable: Operation of the system is possible with locally available labor and support. Reliable: Effluent quality requirements can be met consistently. Currently there are a limited number of appropriate technologies for small communities, which should be considered by a community and their designers. These include conventional and non-conventional systems such as stabilization ponds or lagoons, slow sand filters, land treatment systems, and wetlands (natural or constructed). The non-conventional systems often utilize 'ecological' treatment mechanism (such as aquatic systems or wetlands) and do not have the mechanical parts or energy requirements of conventional systems. Waste Stabilization Ponds are one such solution but sometimes are constrained by land availability, topography, and are not environment friendly. In such locations, natural or constructed wetlands (Reed Beds) could provide an alternative technology. It is what we call a LOW technology, rather than HI TECH

Microbiological and chemical approaches to degradation of mecoprop in a Moving-Bed Biofilm-Reactor

DEFF Research Database (Denmark)

Escola, Monica; Tue Kjærgaard Nielsen, Tue; Hansen, Lars Hestbjerg

Micro-pollutants are ubiquitous in wastewater effluents. Therefore, in-situ treatments of highly polluted water or polishing treatments after classical wastewater treatment have been proposed as a solution. Moving Bed Biofilm-Reactors (MBBRs) are a recent-developed biofilm technology for wastewater...... treatment. MBBRs consist incontain biofilms which are grown on small (1-4 cm diameter) plastic chips that are suspended and mixed in a water tank. These systems have been recognized as robust and versatile. Besides, biofilm systems fdescribe acilitatedemonstrate a clear, but slow, biodegradation of some...... recalcitrant compounds. For all these reasonsThus, MBBRs are pointed as a valuable tool for the elimination of micro-pollutants. Several studies have focused in on describing degradation processes in biofilm by quantifying the loss of micro-pollutants over time. This can be helpful foraid optimizing...

Power partial-discard strategy to obtain improved performance for simulated moving bed chromatography.

Science.gov (United States)

Chung, Ji-Woo; Kim, Kyung-Min; Yoon, Tae-Ung; Kim, Seung-Ik; Jung, Tae-Sung; Han, Sang-Sup; Bae, Youn-Sang

2017-12-22

A novel power partial-discard (PPD) strategy was developed as a variant of the partial-discard (PD) operation to further improve the separation performance of the simulated moving bed (SMB) process. The PPD operation varied the flow rates of discard streams by introducing a new variable, the discard amount (DA) as well as varying the reported variable, discard length (DL), while the conventional PD used fixed discard flow rates. The PPD operations showed significantly improved purities in spite of losses in recoveries. Remarkably, the PPD operation could provide more enhanced purity for a given recovery or more enhanced recovery for a given purity than the PD operation. The two variables, DA and DL, in the PPD operation played a key role in achieving the desired purity and recovery. The PPD operations will be useful for attaining high-purity products with reasonable recoveries. Copyright © 2017 Elsevier B.V. All rights reserved.

Attached biomass growth and substrate utilization rate in a moving bed biofilm reactor

Directory of Open Access Journals (Sweden)

J. J. Marques

2008-12-01

Full Text Available A moving bed bioreactor containing cubes of polyether foam immersed in a synthetic wastewater (an aqueous mixture of meat extract, yeast extract, dextrose, meat peptone, ammonium chloride, potassium chloride, sodium chloride, sodium bicarbonate, potassium mono-hydrogen-phosphate and magnesium sulphate was used to evaluate bacterial growth and biomass yield parameters based on Monod's equation. The wastewater was supplied in the bottom of the equipment flowing ascending in parallel with a diffused air current that provided the mixing of the reactor content. Suspended and attached biomass concentration was measured through gravimetric methods. Good agreement was found between experimental kinetic parameters values and those obtained by other researchers. The only significant difference was the high global biomass content about 2 times the values obtained in conventional processes, providing high performance with volumetric loading rates up to 5.5 kg COD/m³/d.

Development of Moving Bed Technology for Heat Treatment and Grinding of Dismantled Concrete

International Nuclear Information System (INIS)

Kang, Yong

2009-04-01

The factors such as gas or fluid velocity, length, width and depth of each stage, number of Zig-Zag stage, angle of each stage, position of feed stage, size and amount of feed material, amount of treated concrete waste, method of fluid distribution, surface area of heat transfer, position of heater, method of heating, temperature difference between the heater and the material, amount of heat have been found to be important factors in the system. The capability of the system has been analyzed and evaluated by means of total efficiency and grade separation efficiency the experiments by using the simulated Zig-Zag type moving bed flow process with bench scale(3.2m high, Ifi-stage) have shown that the total efficiency has been in the range of 92% - 95% and the grade efficiency of 93% - 95%, respectively, elucidating that the system is quite good

Biological fluidized-bed treatment of groundwater from a manufactured gas plant site

International Nuclear Information System (INIS)

Grey, G.M.; Scheible, O.K.; Maiello, J.A.; Guarini, W.J.; Sutton, P.M.

1995-01-01

Bench- and pilot-scale biological treatability studies were performed as part of a comprehensive study for developing an on-site treatment system for contaminated groundwater at a former manufactured gas plant site. The bench-scale work, which included evaluations of activated sludge and fluidized-bed biological processes, indicated that a carbon-based fluidized-bed process was most appropriate. The process was then demonstrated on a pilot level at the site. The bench and pilot studies demonstrated significant reductions of chemical oxygen demand (COD), and all target organics including polycyclic aromatic hydrocarbons (PAHs) and volatile organic compounds (VOCs)

The use of moving bed bio-reactor to laundry wastewater treatment

Science.gov (United States)

Bering, Sławomira; Mazur, Jacek; Tarnowski, Krzysztof; Janus, Magdalena; Mozia, Sylwia; Waldemar Morawski, Antoni

2017-11-01

Large laboratory scale biological treatment test of industrial real wastewater, generated in industrial big laundry, has been conducted in the period of May 2016-August 2016. The research aimed at selection of laundry wastewater treatment technology included tests of two-stage Moving Bed Bio Reactor (MBBR), with two reactors filled with carriers Kaldnes K5 (specific area - 800 m2/m3), have been realized in aerobic condition. Operating on site, in the laundry, reactors have been fed real wastewater from laundry retention tank. To the laundry wastewater, contained mainly surfactants and impurities originating from washed fabrics, a solution of urea to supplement nitrogen content and a solution of acid to correct pH have been added. Daily flow of raw wastewater Qd was equal to 0.6-0.8 m3/d. The values of determined wastewater quality indicators showed that substantial decrease of pollutants content have been reached: BOD5 by 94.7-98.1%, COD by 86.9-93.5%, the sum of anionic and nonionic surfactants by 98.7-99.8%. The quality of the purified wastewater, after star-up period, meets the legal requirements regarding the standards for wastewater discharged to the environment.

Biosystem of seaweed beds coexisting with power plants; Denryoku hatsudensho to kyoseisuru moba no seitaikei

Energy Technology Data Exchange (ETDEWEB)

Ono, M. [Kochi Univ., Kochi (Japan)

1996-03-05

Recently, seaweed beds on the coasts of Japan are decreasing rapidly, and it has been demanded that they should be restored. As one of the restoring methods, plans are investigated to utilize coast structures near power plants and wave absorbing dykes, which are artificial seaweed beds with dense seaweed forests and offer favorable areas for living creatures, for the purpose of building new seaweed beds and marine pastures. For seaweed bed building projects, it is necessary to show the economical effect of seaweed beds. Recently, absorption of carbon dioxide, nitrogen, and phosphoric acid dissolved in the sea has been attracting attention as a role of seaweed beds. Creation of Zostera beds is a difficult enterprise. The mound creation of the seaweed bed at Ikata, Aichi Prefecture, Japan is successful because there is a good seaweed bed in the periphery which can supply sufficient seeds (spores) to the bed. With the development of the seaweed bed, a concrete block rocky beach reef was developed which is provided with a function of dwelling places for shells and lobsters. The Fishery Ministry is promoting a large scale ocean pasture plan on the coast of Japan with the target period of the 21st century, and extension of seaweed bed areas is considered to be the major project. 8 refs., 7 figs.

Energy, environmental and operation aspects of a SRF-fired fluidized bed waste-to-energy plant.

Science.gov (United States)

De Gisi, Sabino; Chiarelli, Agnese; Tagliente, Luca; Notarnicola, Michele

2018-03-01

A methodology based on the ISO 14031:2013 guideline has been developed and applied to a full-scale fluidized bed waste to energy plant (WtE) burning solid recovered fuel (SRF). With reference to 3years of operation, the data on energy and environmental performance, on raw materials consumptions such as sand and diesel fuel, accidental reasons of plant shutdown, have been acquired and analyzed. The obtained results have allowed to quantify the energy and environmental performance of the WtE plant under investigation by varying the amount and mixings of the inlet waste, available in form of thickened and fluff (similar to coriander) SRF. In terms of the energy performance, the fluidized bed technology applied to the SRF was able to guarantee an adequate production of electricity (satisfying the market demands), showing a relative flexibility with respect to the inlet waste. In terms of net energy production efficiency, the plant showed values in the range of 13.8-14.9% in line with similar installations. In terms of the environmental performance, the adoption of a cleaning system based on SNCR (Selective Non Catalitic Reduction)+semi-dry scrubbing+Fabric filter generated emissions usually well below the limits set by the EU Directive 2000/76/EC as well as the Italian Law 46/2014 (more restrictive) with reference to all the key parameters. In terms of the plant shutdown, the majority of problems focused on the combustion chamber and boiler due to the erosion of the refractory material of the furnace as well as to the breaking of the superheaters of the boiler. In contrast, the mechanical and electrical causes, along with those related to the control and instrumentation system, were of secondary importance. The sand bed de-fluidization was also among the leading causes of a frequent plant shutdown. In particular, results showed how although the SRF presents standard characteristics, the use of different mixtures may affect the number of plant shutdowns. The full

Optimization of startup and shutdown operation of simulated moving bed chromatographic processes.

Science.gov (United States)

Li, Suzhou; Kawajiri, Yoshiaki; Raisch, Jörg; Seidel-Morgenstern, Andreas

2011-06-24

This paper presents new multistage optimal startup and shutdown strategies for simulated moving bed (SMB) chromatographic processes. The proposed concept allows to adjust transient operating conditions stage-wise, and provides capability to improve transient performance and to fulfill product quality specifications simultaneously. A specially tailored decomposition algorithm is developed to ensure computational tractability of the resulting dynamic optimization problems. By examining the transient operation of a literature separation example characterized by nonlinear competitive isotherm, the feasibility of the solution approach is demonstrated, and the performance of the conventional and multistage optimal transient regimes is evaluated systematically. The quantitative results clearly show that the optimal operating policies not only allow to significantly reduce both duration of the transient phase and desorbent consumption, but also enable on-spec production even during startup and shutdown periods. With the aid of the developed transient procedures, short-term separation campaigns with small batch sizes can be performed more flexibly and efficiently by SMB chromatography. Copyright © 2011 Elsevier B.V. All rights reserved.

Statistical description of flume experiments on mixed-size bed-load transport and bed armoring processes

Science.gov (United States)

Chen, D.; Zhang, Y.

2008-12-01

The objective of this paper is to describe the statistical properties of experiments on non-uniform bed-load transport as well as the mechanism of bed armoring processes. Despite substantial effort made over the last two decades, the ability to compute the bed-load flux in a turbulent system remains poor. The major obstacles include the poor understanding of the formation of armor lays on bed surfaces. Such a layer is much flow-resistible than the underlying material and therefore significantly inhibits sediment transport from the reach. To study the problem, we conducted a flume study for mixed sand/gravel sediments. We observed that aggregated sediment blocks were the most common characters in armor layers - the largest sizes resist hydraulic forces, while the smaller sizes add interlocking support and prevent loss of fine material through gaps between the larger particles. Fractional transport rates with the existing of armor layers were measured with time by sediment trapping method at the end of flume. To address the intermittent and time-varying behavior of bed-load transport during bed armoring processes, we investigated the probability distribution of the fractional bed-load transport rates, and the underlying dynamic model derived from the continuous time random walk framework. Results indicate that it is critical to consider the impact of armor layers when a flow is sufficient to move some of the finer particles and yet insufficient to move all the larger particles on a channel bed.

Optimizing aeration rates for minimizing membrane fouling and its effect on sludge characteristics in a moving bed membrane bioreactor

International Nuclear Information System (INIS)

Rahimi, Yousef; Torabian, Ali; Mehrdadi, Naser; Habibi-Rezaie, Mehran; Pezeshk, Hamid; Nabi-Bidhendi, Gholam-Reza

2011-01-01

Research highlights: → There is an optimum aeration rate in the MBMBR process compartments. → Optimum aeration rate maximizes nutrients removal. → Optimum aeration rate minimizes membrane fouling. → Both aeration rates in MBBR and membrane compartment can affect on membrane permeability. - Abstract: In MBR processes, sufficient aeration is necessary to maintain sustainable flux and to retard membrane fouling. Membrane permeability, sludge characteristics, nutrient removal and biomass growth at various air flow rates in the membrane and moving bed biofilm reactor (MBBR) compartments were studied in a pilot plant. The highest nitrogen and phosphorous removal rates were found at MBBR aeration rates of 151 and 85 L h -1 and a specific aeration demand per membrane area (SAD m ) of 1.2 and 0.4m air 3 m -2 h -1 , respectively. A linear correlation was found between the amount of attached biofilm and the nutrient removal rate. The aeration rate in the MBBR compartment and SAD m significantly influenced the sludge characteristics and membrane permeability. The optimum combination of the aeration rate in the MBBR compartment and SAD m were 151 L h -1 and 0.8-1.2m air 3 m membrane -2 h -1 , respectively.

Optimizing aeration rates for minimizing membrane fouling and its effect on sludge characteristics in a moving bed membrane bioreactor

Energy Technology Data Exchange (ETDEWEB)

Rahimi, Yousef, E-mail: yrahimi@ut.ac.ir [Department of Civil and Environmental Engineering, Graduate Faculty of Environment, University of Tehran, No. 25 Qods St., Enghelab Ave., Tehran (Iran, Islamic Republic of); Torabian, Ali, E-mail: atorabi@ut.ac.ir [Department of Civil and Environmental Engineering, Graduate Faculty of Environment, University of Tehran, No. 25 Qods St., Enghelab Ave., Tehran (Iran, Islamic Republic of); Mehrdadi, Naser, E-mail: mehrdadi@ut.ac.ir [Department of Civil and Environmental Engineering, Graduate Faculty of Environment, University of Tehran, No. 25 Qods St., Enghelab Ave., Tehran (Iran, Islamic Republic of); Habibi-Rezaie, Mehran, E-mail: mhabibi@khayam.ut.ac.ir [Department of Biotechnology, Faculty of Biology, College of Science, University of Tehran, No. 25 Qods St., Enghelab Ave., Tehran (Iran, Islamic Republic of); Pezeshk, Hamid, E-mail: pezeshk@khayam.ut.ac.ir [Department of Statistics, Faculty of Mathematics and Computer, College of Science, University of Tehran, No. 25 Qods St., Enghelab Ave., Tehran (Iran, Islamic Republic of); Nabi-Bidhendi, Gholam-Reza, E-mail: ghhendi@ut.ac.ir [Department of Civil and Environmental Engineering, Graduate Faculty of Environment, University of Tehran, No. 25 Qods St., Enghelab Ave., Tehran (Iran, Islamic Republic of)

2011-02-28

Research highlights: {yields} There is an optimum aeration rate in the MBMBR process compartments. {yields} Optimum aeration rate maximizes nutrients removal. {yields} Optimum aeration rate minimizes membrane fouling. {yields} Both aeration rates in MBBR and membrane compartment can affect on membrane permeability. - Abstract: In MBR processes, sufficient aeration is necessary to maintain sustainable flux and to retard membrane fouling. Membrane permeability, sludge characteristics, nutrient removal and biomass growth at various air flow rates in the membrane and moving bed biofilm reactor (MBBR) compartments were studied in a pilot plant. The highest nitrogen and phosphorous removal rates were found at MBBR aeration rates of 151 and 85 L h{sup -1} and a specific aeration demand per membrane area (SAD{sub m}) of 1.2 and 0.4m{sub air}{sup 3} m{sup -2} h{sup -1}, respectively. A linear correlation was found between the amount of attached biofilm and the nutrient removal rate. The aeration rate in the MBBR compartment and SAD{sub m} significantly influenced the sludge characteristics and membrane permeability. The optimum combination of the aeration rate in the MBBR compartment and SAD{sub m} were 151 L h{sup -1} and 0.8-1.2m{sub air}{sup 3}m{sub membrane}{sup -2} h{sup -1}, respectively.

Biodegradation of benzotriazoles and hydroxy-benzothiazole in wastewater by activated sludge and moving bed biofilm reactor systems

DEFF Research Database (Denmark)

Mazioti, Aikaterini A.; Stasinakis, Athanasios S.; Pantazi, Ypapanti

2015-01-01

Two laboratory scale fully aerated continuous flow wastewater treatment systems were used to compare the removal of five benzotriazoles and one benzothiazole by suspended and attached growth biomass. The Activated Sludge system was operated under low organic loading conditions. The Moving Bed...... in significantly lower biodegradation for 4 out of 6 examined compounds. Calculation of specific removal rates (normalised to biomass) revealed that attached biomass had higher biodegradation potential for target compounds comparing to suspended biomass. Clear differences in the biodegradation ability of attached...... biomass grown in different bioreactors of MBBR systems were also observed. Batch experiments showed that micropollutants biodegradation by both types of biomass is co-metabolic....

Effects of a malfunctional column on conventional and FeedCol-simulated moving bed chromatography performance.

Science.gov (United States)

Song, Ji-Yeon; Oh, Donghoon; Lee, Chang-Ha

2015-07-17

The effects of a malfunctional column on the performance of a simulated moving bed (SMB) process were studied experimentally and theoretically. The experimental results of conventional four-zone SMB (2-2-2-2 configuration) and FeedCol operation (2-2-2-2 configuration with one feed column) with one malfunctional column were compared with simulation results of the corresponding SMB processes with a normal column configuration. The malfunctional column in SMB processes significantly deteriorated raffinate purity. However, the extract purity was equivalent or slightly improved compared with the corresponding normal SMB operation because the complete separation zone of the malfunctional column moved to a lower flow rate range in zones II and III. With the malfunctional column configuration, FeedCol operation gave better experimental performance (up to 7%) than conventional SMB operation because controlling product purity with FeedCol operation was more flexible through the use of two additional operating variables, injection time and injection length. Thus, compared with conventional SMB separation, extract with equivalent or slightly better purity could be produced from FeedCol operation even with a malfunctional column, while minimizing the decrease in raffinate purity (less than 2%). Copyright © 2015 Elsevier B.V. All rights reserved.

The Safety of Hospital Beds

Science.gov (United States)

Gervais, Pierre; Pooler, Charlotte; Merryweather, Andrew; Doig, Alexa K.; Bloswick, Donald

2015-01-01

To explore the safety of the standard and the low hospital bed, we report on a microanalysis of 15 patients’ ability to ingress, move about the bed, and egress. The 15 participants were purposefully selected with various disabilities. Bed conditions were randomized with side rails up or down and one low bed with side rails down. We explored the patients’ use of the side rails, bed height, ability to lift their legs onto the mattress, and ability to turn, egress, and walk back to the chair. The standard bed was too high for some participants, both for ingress and egress. Side rails were used by most participants when entering, turning in bed, and exiting. We recommend that side rails be reconsidered as a means to facilitate in-bed movement, ingress, and egress. Furthermore, single deck height settings for all patients are not optimal. Low beds as a safety measure must be re-evaluated. PMID:28462302

7 CFR 330.203 - Action on applications for permits to move plant pests; form of and conditions in permits.

Science.gov (United States)

2010-01-01

... 7 Agriculture 5 2010-01-01 2010-01-01 false Action on applications for permits to move plant pests... PEST REGULATIONS; GENERAL; PLANT PESTS; SOIL, STONE, AND QUARRY PRODUCTS; GARBAGE Movement of Plant Pests § 330.203 Action on applications for permits to move plant pests; form of and conditions in...

Using flowering and heat-loss models for improving greenhouse energy-use efficiency in annual bedding plant production

Science.gov (United States)

In temperate climates, annual bedding plants are typically produced in heated greenhouses from late winter through early summer. Temperature, photoperiod, light intensity, and transplant date are commonly manipulated during commercial production so that plants are in flower for predetermined market ...

An integrated mathematical model for chemical oxygen demand (COD) removal in moving bed biofilm reactors (MBBR) including predation and hydrolysis.

Science.gov (United States)

Revilla, Marta; Galán, Berta; Viguri, Javier R

2016-07-01

An integrated mathematical model is proposed for modelling a moving bed biofilm reactor (MBBR) for removal of chemical oxygen demand (COD) under aerobic conditions. The composite model combines the following: (i) a one-dimensional biofilm model, (ii) a bulk liquid model, and (iii) biological processes in the bulk liquid and biofilm considering the interactions among autotrophic, heterotrophic and predator microorganisms. Depending on the values for the soluble biodegradable COD loading rate (SCLR), the model takes into account a) the hydrolysis of slowly biodegradable compounds in the bulk liquid, and b) the growth of predator microorganisms in the bulk liquid and in the biofilm. The integration of the model and the SCLR allows a general description of the behaviour of COD removal by the MBBR under various conditions. The model is applied for two in-series MBBR wastewater plant from an integrated cellulose and viscose production and accurately describes the experimental concentrations of COD, total suspended solids (TSS), nitrogen and phosphorous obtained during 14 months working at different SCLRs and nutrient dosages. The representation of the microorganism group distribution in the biofilm and in the bulk liquid allow for verification of the presence of predator microorganisms in the second reactor under some operational conditions. Copyright © 2016 Elsevier Ltd. All rights reserved.

Gaseous emissions from sewage sludge combustion in a moving bed combustor.

Science.gov (United States)

Batistella, Luciane; Silva, Valdemar; Suzin, Renato C; Virmond, Elaine; Althoff, Chrtistine A; Moreira, Regina F P M; José, Humberto J

2015-12-01

Substantial increase in sewage sludge generation in recent years requires suitable destination for this residue. This study evaluated the gaseous emissions generated during combustion of an aerobic sewage sludge in a pilot scale moving bed reactor. To utilize the heat generated during combustion, the exhaust gas was applied to the raw sludge drying process. The gaseous emissions were analyzed both after the combustion and drying steps. The results of the sewage sludge characterization showed the energy potential of this residue (LHV equal to 14.5 MJ kg(-1), db) and low concentration of metals, polycyclic aromatic hydrocarbons (PAH), polychlorinated dibenzo-p-dioxins (PCDD) and polychlorinated dibenzofurans (PCDF). The concentration of CO, NOx, BTEX (benzene, toluene, ethylbenzene and xylenes) emitted from the sludge combustion process were lower than the legal limits. The overall sludge combustion and drying process showed low emissions of PCDD/PCDF (0.42 ng I-TEQ N m(-3)). BTEX and PAH emissions were not detected. Even with the high nitrogen concentration in the raw feed (5.88% db), the sludge combustion process presented NOx emissions below the legal limit, which results from the combination of appropriate feed rate (A/F ratio), excess air, and mainly the low temperature kept inside the combustion chamber. It was found that the level of CO emissions from the overall sludge process depends on the dryer operating conditions, such as the oxygen content and the drying temperature, which have to be controlled throughout the process in order to achieve low CO levels. The aerobic sewage sludge combustion process generated high SO2 concentration due to the high sulfur content (0.67 wt%, db) and low calcium concentration (22.99 g kg(-1)) found in the sludge. The high concentration of SO2 in the flue gas (4776.77 mg N m(-3)) is the main factor inhibiting PCDD/PCDF formation. Further changes are needed in the pilot plant scheme to reduce SO2 and particulate matter emissions

Operating experience and development of fluidized-bed denitrators for UNH at Tokai Reprocessing Plant

International Nuclear Information System (INIS)

Sasaki, Minoru; Nakamichi, Hideya; Takeda, Seiichiro; Kubota, Kanya; Katoh, Shuji

1983-01-01

The fluidized bed denitrator for uranyl nitrate hexahydrate (UNH) at Tokai reprocessing plant has been operated since 1976. About 170 tons of spent fuel have been reprocessed, and the denitrator has encountered numerous operational problems during the period. This report deals with these technical problems and the associated countermeasures taken, including the dismantling and reconstruction of equipment and the improvement of operating method. The major problems encountered were as follows: (1) the crystallization of UNH on the UNH feeding line, (2) spray nozzle clogging and candle filter clogging, (3) particle growth, (4) plugging of the drawing-out line by nozzle caking, and (5) slugging in fluidized-bed denitration. The total quantity and quality of UO 3 products obtained so far at the plant are also briefly described together with some future R and D programs such as the improvement of UO 3 reactivity and the automation of denitrators. (Aoki, K.)

Fluid-bed combustion

Energy Technology Data Exchange (ETDEWEB)

Hunt, G.; Schoebotham, N.

1981-02-01

In Energy Equipment Company's two-stage fluidized bed system, partial combustion in a fluidized bed is followed by burn-off of the generated gases above the bed. The system can be retrofitted to existing boilers, and can burn small, high ash coal efficiently. It has advantages when used as a hot gas generator for process drying. Tests on a boiler at a Cadbury Schweppes plant are reported.

Behavior of gasketless deep bed charcoal filters for radioiodine removal in LWR power plants

International Nuclear Information System (INIS)

Wilhelm, J.G.; Deuber, H.; Furrer, J.; Gerlach, K.

1981-01-01

The removal efficiency of radioiodine filters can be affected by mechanical leakage, aging and poisoning, desorption of radioiodine originally removed by the activated carbon and also by the occurrence of penetrating iodine compounds. To provide high decontamination factors only the gasketless deep bed filter type seems to be appropriate. The experience gathered and the data given in this paper are based on the surveillance testing of radioiodine filters in all German nuclear power plants and on laboratory research work which has been done over years to evaluate the operating behavior of deep bed radioiodine filters and to prove their reliability

Inhibition and recovery of nitrification in treating real coal gasification wastewater with moving bed biofilm reactor

Institute of Scientific and Technical Information of China (English)

Huiqiang Li; Hongjun Han; Maoan Du; Wei Wang

2011-01-01

Moving bed biofilm reactor (MBBR) was used to treat real coal gasification wastewater.Nitrification of the MBBR was inhibited almost completely during start-up period.Sudden increase of influent total NH3 concentration was the main factor inducing nitrification inhibition.Increasing DO concentration in the bulk liquid (from 2 to 3 mg/L) had little effect on nitrification recovery.Nitrification of the MBBR recovered partially by the addition of nitrifying sludge into the reactor and almost ceased within 5 days.Nitrification ratio of the MBBR achieved 65％ within 12 days by increasing dilute ratio of the influent wastewater with tap water.The ratio of nitrification decreased to 25％ when infiuent COD concentration increased from 650 to 1000 mg/L after nitrification recovery and recovered 70％for another 4 days.

Modern fluidized bed combustion in Ostrava-Karvina cogeneration plants

Energy Technology Data Exchange (ETDEWEB)

Mazac, V. [Energoprojekt Praha, Ostrava (Czechoslovakia); Novacek, A. [Moravskoslezske teplamy, Ostrava (Czechoslovakia); Volny, J. [Templamy Karvina (Czechoslovakia)

1995-12-01

The contemporary situation of our environment claims the sensitive approach to solving effective conversion of energy. Limited supplies of noble fuels and their prices evoke the need to use new combustion technologies of accessible fuels in given region without negative ecological influences. Energoproject participates in the preparation of the two projects in Ostrava-Karvin{acute a} black coal field in Czech Republic. The most effective usage of fuel energy is the combined of electricity and heat. If this physical principle is supported by a pressurized fluidized bed combustion (PFBC) one obtains a high electricity/heat ratio integrated steam-gas cycle on the basis of solid fuel. Cogeneration plant Toebovice is the dominant source (600 MW{sub th}) of Ostrava district heating system (1100 MW{sub th}). The high utilization of the installed output and utilization of the clean, compact and efficient of the PFBC technology is the principal but not the single reason for the selection of the Toebovice power plant as the first cogeneration plant for installation of the PFBC in Czech Republic. The boiler will burn black coal from the neighboring coal basin.

Testing of downstream catalysts for tar destruction with a guard bed in a fluidised bed biomass gasifier at pilot plant scale

Energy Technology Data Exchange (ETDEWEB)

Aznar, M.P.; Frances, E.; Campos, I.J.; Martin, J.A.; Gil, J. [Saragossa Univ. (Spain). Dept. of Chemistry and Environment Engineering; Corella, J. [Complutense Univ. of Madrid (Spain). Dept. of Chemical Engineering

1996-12-31

A new pilot plant for advanced gasification of biomass in a fast fluidised bed is now fully operative at University of Saragossa, Spain. It is a `3rd generation` pilot plant. It has been built up after having used two previous pilot plants for biomass gasification. The main characteristic of this pilot plant is that it has two catalytic reactors connected in series, downstream the biomass gasifier. Such reactors, of 4 cm i.d., are placed in a slip stream in a by-pass from the main gasifier exit gas. The gasification is made at atmospheric pressure, with flow rates of 3-50 kg/in, using steam + O{sub 2} mixtures as the gasifying agent. Several commercial Ni steam-reforming catalyst are being tested under a realistic raw gas composition. Tar eliminations or destructions higher than 99 % are easily achieved. (orig.) 2 refs.

Testing of downstream catalysts for tar destruction with a guard bed in a fluidised bed biomass gasifier at pilot plant scale

Energy Technology Data Exchange (ETDEWEB)

Aznar, M P; Frances, E; Campos, I J; Martin, J A; Gil, J [Saragossa Univ. (Spain). Dept. of Chemistry and Environment Engineering; Corella, J [Complutense Univ. of Madrid (Spain). Dept. of Chemical Engineering

1997-12-31

A new pilot plant for advanced gasification of biomass in a fast fluidised bed is now fully operative at University of Saragossa, Spain. It is a `3rd generation` pilot plant. It has been built up after having used two previous pilot plants for biomass gasification. The main characteristic of this pilot plant is that it has two catalytic reactors connected in series, downstream the biomass gasifier. Such reactors, of 4 cm i.d., are placed in a slip stream in a by-pass from the main gasifier exit gas. The gasification is made at atmospheric pressure, with flow rates of 3-50 kg/in, using steam + O{sub 2} mixtures as the gasifying agent. Several commercial Ni steam-reforming catalyst are being tested under a realistic raw gas composition. Tar eliminations or destructions higher than 99 % are easily achieved. (orig.) 2 refs.

Performance of Sandy Dry Beds for sludge dewatering

International Nuclear Information System (INIS)

Al-Muzaini, S.

2003-01-01

Sludge produced by the Jahra treatment plant was assessed. The assessment was directed at determining the performance of sand drying beds. The assessment of quality of the sludge produced was based on the standards for land application of sewage sludge. Analyses were carried out for trace heavy metals and bacteria. The results of analyses showed that the sludge produced was high in organic matter and sand content but low in heavy metals. The collected data indicated that the sand drying beds at the Jahra treatment plant are at present inadequate to handle the projected sludge production. The investigation showed that the sand drying beds are fully used and the plant will require 3-4 times the capacity of the existing drying beds when the plant becomes fully operational. In addition, these sand drying beds are subjected to uncontrollable conditions such as temperature, rainfall and sludge drainage rate. Thus, sand drying beds have become less popular as a dewatering system. This paper evaluates the performance of the existing sand drying beds and suggests the most appropriate technology to alleviate the above mentioned problems. (author)

A technical pilot plant assessment of flue gas desulfurisation in a circulating fluidised bed

Energy Technology Data Exchange (ETDEWEB)

Gutierrez, F.J.; Ollero, P. [Universidad de Sevilla (Spain). Dept. de Ingenieria Quimica y Ambiental; Cabanillas, A.; Otero, J. [Centro de Investigaciones Energeticas y Medioambientales, (CIEMAT), Madrid (Spain)

2002-11-01

Flue gas desulfurisation in a circulating fluidised bed absorber (CFBA) is quite a novel dry desulfurisation technology [6th International Conference on Circulating Fluidised Beds (1999) 601] that shows significant advantages in comparison with other dry technologies and that could also be competitive with the widely-used wet FGD technology. This experimental study analyses the performance of a flue gas treatment plant comprising a CFBA and an electrostatic precipitator (ESP). The most significant aspects considered in this study are: the effect of precollecting the fly ash, the effect of the SO{sub 2} inlet concentration, the effect of power plant load changes, the contribution of the final particulate control equipment to the overall SO{sub 2} removal efficiency and the impact of the desulfurisation unit on the ESP behaviour and its final dust emissions. In addition, the behaviour of the integrated CFBA-ESP system with respect to the main operating parameters was studied by means of a fractional factorial design of experiments. All this experimental work was carried out in a 3-MWe equivalent pilot plant that processes real gases withdrawn from the Los Barrios Power Plant. Processing a flue gas with up to 2000 ppm SO{sub 2} concentration, a sulfur removal of 95-97% with a lime utilisation of 75% was achieved. A simple regression model to evaluate the efficiency of the whole system is also proposed.(author)

Enrichment of thallium in fly ashes in a Spanish circulating fluidized-bed combustion plant

OpenAIRE

López Antón, María Antonia; Spears, D. Alan; Díaz Somoano, Mercedes; Díaz, Luis; Martínez Tarazona, María Rosa

2015-01-01

This work evaluates the behavior of thallium in a 50 MW industrial circulating fluidized-bed combustion plant (CFBC), focusing on the distribution of this element among the bottom and fly ashes separated by the solid retention devices in the plant. The results show that thallium species are mainly retained in the solid by-products and are not emitted to air with flue gases in significant amounts, proving that this technology is a more effective means of preventing thallium emissions than pulv...

Application of CaO-Based Bed Material for Dual Fluidized Bed Steam Biomass Gasification

Science.gov (United States)

Koppatz, S.; Pfeifer, C.; Kreuzeder, A.; Soukup, G.; Hofbauer, H.

Gasification of biomass is a suitable option for decentralized energy supply based on renewable sources in the range of up to 50 MW fuel input. The paper presents the dual fluidized bed (DFB) steam gasification process, which is applied to generate high quality and nitrogen-free product gas. Essential part of the DFB process is the bed material used in the fluidized reactors, which has significant impact on the product gas quality. By the use of catalytically active bed materials the performance of the overall process is increased, since the bed material favors reactions of the steam gasification. In particular, tar reforming reactions are favored. Within the paper, the pilot plant based on the DFB process with 100kW fuel input at Vienna University of Technology, Austria is presented. Actual investigations with focus on CaO-based bed materials (limestone) as well as with natural olivine as bed material were carried out at the pilot plant. The application of CaO-based bed material shows mainly decreased tar content in the product gas in contrast to experiments with olivine as bed material. The paper presents the results of steam gasification experiments with limestone and olivine, whereby the product gas composition as well as the tar content and the tar composition are outlined.

Research of fluidized bed cement clinker sintering system by pilot plant; Ryudosho cement shosei gijutsu no kaihatsu. 7

Energy Technology Data Exchange (ETDEWEB)

Sugiyama, T [Center for Coal Utilization, Japan, Tokyo (Japan); Sato, N; Hashimoto, I; Nakatsuka, M [The Cement Association of Japan, Tokyo (Japan)

1996-09-01

While a cement manufacturing process generally performs sintering by using a rotary kiln, a development work has been carried out as a subsidy operation of the Agency of Natural Resources and Energy on a cement sintering technology using a fluidized bed consisted of two furnaces: a jet flow bed granulating furnace and a fluidized bed sintering furnace. This paper reports the results of tests and researches performed during fiscal 1995. A plant with a scale of 20 ton-a-day production started in 1993 after having gone through bench scale tests. The year 1995 conducted by August its performance evaluation, review of the operation method and the safety criteria, and generalization of the tests. A multi-stage cyclone system has been employed in the preheating equipment for cement material powder. A number of improvements have been realized in the aspects of construction and operation, such as stabilization of dust collecting efficiency by employing a high-efficiency type cyclone, and operation with reduced pressure variation. Based on these results, a construction had been progressed in parallel on a new plant upscaled to 200 ton-a-day production. The new plant was completed in December, 1995. 9 figs., 8 tabs.

Moving-bed: a stable and rapidly recovering process; El sistema de biomasa fija sobre lecho movil: un proceso estable y de rapida recuperacion

Energy Technology Data Exchange (ETDEWEB)

Velasco Munguira, A.; Jorda Llona, J. R.; Farre Solsona, C.; Cortacans Torre, J. A.

2005-07-01

A moving-bed biofilm process is presented for the treatment of soft drink factory outlet. Once the system has been stabilized regarding oxygen, nutrient addition and pH control, the process goes on up to a 95% and over 98% reduction of COD and BOD, respectively, rapidly recovering from toxic shacks. Sludge production is larger than expected due to a higher yield of bacteria growing on a sugar-rich influent. (Author) 4 refs.

1974 conceptual design description of a bedded salt pilot plant in southeast New Mexico

International Nuclear Information System (INIS)

1977-06-01

The policy of the United States Atomic Energy Commission is to take custody of all commercial high-level radioactive wastes and maintain control of them in perpetuity. This policy (Title 10, Code of Federal Regulations, Part 50, Appendix F) requires that the high-level wastes from nuclear fuels reprocessing plants be solidified within five years after reprocessing and then shipped to a federal repository within ten years after reprocessing. Ultimate disposal sites and/or methods have not yet been selected and are not expected to be ready when waste deliveries begin about 1983. Therefore, the AEC plans to build an interim storage facility, called Retrievable Surface Storage Facility (RSSF), to store and isolate the waste from man and his environment until the suitability of the permanent repository is demonstrated and public acceptance has been established. Meantime, the AEC is proceeding with the study and development of an ultimate disposal method. Bedded salt is being considered for ultimate waste disposal, and work is in progress to develop a Bedded Salt Pilot Plant to demonstrate its acceptability. The pilot plant will permit in situ verification of laboratory work on the interaction of heat and radioactivity of the waste with the salt and surroundings. One concept of such a pilot facility is described

Methods for growth regulation of greenhouse produced ornamental pot- and bedding plants – a current review

Directory of Open Access Journals (Sweden)

Bergstrand Karl-Johan I.

2017-06-01

Full Text Available Chemical plant growth regulators (PGRs are used in the production of ornamental potted and bedding plants. Growth control is needed for maximizing production per unit area, reducing transportation costs and to obtain a desired visual quality. However, the use of PGRs is associated with toxicity risks to humans and the environment. In many countries the availability of PGRs is restricted as few substances are registered for use. A number of alternative methods have been suggested. The methods include genetic methods (breeding and crop cultivation practices such as fertigation, temperature and light management. A lot of research into “alternative” growth regulation was performed during the 1980-1990s, revealing several possible ways of using different climatic factors to optimize plant growth with respect to plant height. In recent years, the interest in climatic growth regulation has been resurrected, not least due to the coming phase-out of the plant growth regulator chlormequat chloride (CCC. Today, authorities in many countries are aiming towards reducing the use of agrochemicals. At the same time, there is a strong demand from consumers for products produced without chemicals. This article provides a broad overview of available methods for non-chemical growth control. It is concluded that a combination of plant breeding and management of temperature, fertigation and light management has the potential of replacing chemical growth regulators in the commercial production of ornamental pot- and bedding plants.

DOLOMITE DESULFURIZATION BEHAVIOR IN A BUBBLING FLUIDIZED BED PILOT PLANT FOR HIGH ASH COAL

Directory of Open Access Journals (Sweden)

G. M. F. Gomes

Full Text Available Abstract Although fluidized bed in situ desulphurization from coal combustion has been widely studied, there are aspects that remain under investigation. Additionally, few publications address Brazilian coal desulphurization via fluidized beds. This study used a 250 kWth bubbling fluidized bed pilot plant to analyze different aspects of the dolomite desulphurization of two Brazilian coals. Superficial velocities of 0.38 and 0.46 m/s, flue gas recycling, Ca/S molar ratios and elutriation were assessed. Results confirmed the influence of the Ca/S molar ratio and superficial velocity - SO2 conversion up to 60.5% was achieved for one coal type, and 70.9% was achieved for the other type. A recycling ratio of 54.6% could increase SO2 conversion up to 86.1%. Elutriation and collection of ashes and Ca-containing products did not present the same behavior because a lower wt. % of CaO was collected by the gas controlled mechanism compared to the ash.

Performance analysis and pilot plant test results for the Komorany fluidized bed retrofit project

Energy Technology Data Exchange (ETDEWEB)

Snow, G.C. [POWER International, Inc., Coeur d`Alene, ID (United States)

1995-12-01

Detailed heat and mass balance calculations and emission performance projections are presented for an atmospheric fluidized bed boiler bottom retrofit at the 927 MWt (steam output) Komorany power station and district heating plant in the Czech Republic. Each of the ten existing boilers are traveling grate stoker units firing a local, low-rank brown coal. This fuel, considered to be representative of much of the coal deposits in Central Europe, is characterized by an average gross calorific value of 10.5 MJ/kg (4,530 Btu/lb), an average dry basis ash content of 47 %, and a maximum dry basis sulfur content of 1.8 % (3.4 % on a dry, ash free basis). The same fuel supply, together with limestone supplied from the region will be utilized in the retrofit fluidized bed boilers. The primary objectives of this retrofit program are, (1) reduce emissions to a level at or below the new Czech Clean Air Act, and (2) restore plant capacity to the original specification. As a result of the AFBC retrofit and plant upgrade, the particulate matter emissions will be reduced by over 98 percent, SO{sub 2} emissions will be reduced by 88 percent, and NO{sub x} emissions will be reduced by 38 percent compared to the present grate-fired configuration. The decrease in SO{sub 2} emissions resulting from the fluidized bed retrofit was initially predicted based on fuel sulfur content, including the distribution among organic, pyritic, and sulfate forms; the ash alkalinity; and the estimated limestone calcium utilization efficiency. The methodology and the results of this prediction were confirmed and extended by pilot scale combustion trials at a 1.0 MWt (fuel input), variable configuration test facility in France.

Bedding Improves Yellow-Poplar Growth on Fragipan Soils

Science.gov (United States)

John K. Francis

1979-01-01

Yellow-poplar can be grown on soils that have a shallow fragipan--but unless such sites are bedded, growth is likely to be extremely poor. In a Tennessee study, bedding increased height of planted yellow-poplar over 5 years, but fertilizer did not. Because of the cost of bedding and the availability of nonfragipan sites, it would ordinarily be better not to plant...

Advanced circulating fluidised bed technology (CFB) for large-scale solid biomass fuel firing power plants

Energy Technology Data Exchange (ETDEWEB)

Jaentti, Timo; Zabetta, Edgardo Coda; Nuortimo, Kalle [Foster Wheeler Energia Oy, Varkaus (Finland)

2013-04-01

Worldwide the nations are taking initiatives to counteract global warming by reducing their greenhouse gas emissions. Efforts to increase boiler efficiency and the use of biomass and other solid renewable fuels are well in line with these objectives. Circulating fluidised bed boilers (CFB) are ideal for efficient power generation, capable to fire a broad variety of solid biomass fuels from small CHP plants to large utility power plants. Relevant boiler references in commercial operation are made for Finland and Poland.

Decolourization of remazol black-5 textile dyes using moving bed bio-film reactor

Science.gov (United States)

Pratiwi, R.; Notodarmojo, S.; Helmy, Q.

2018-01-01

The desizing and dyeing processes in the textile industries produces wastewaster containing high concentration of organic matter and colour, so it needs treatment before released to environment. In this research, removal of azo dye (Remazol Black 5/RB 5) and organic as COD was performed using Moving Bed Biofilm Reactor (MBBR). MBBR is biological treatment process with attached growth media system that can increase removal of organic matter in textile wastewater. The effectiveness of ozonation as pre-treatment process to increase the removal efficiency in MBBR was studied. The results showed that in MBBR batch system with detention time of 1 hour, pre-treatment with ozonation prior to MBBR process able to increase the colour removal efficiency of up to 86.74%. While on the reactor without ozone pre-treatment, the colour removal efficiency of up to 68.6% was achieved. From the continuous reactor experiments found that both colour and COD removal efficiency depends on time detention of RB-5 dyes in the system. The higher of detention time, the higher of colour and COD removal efficiency. It was found that optimum removal of colour and COD was achieved in 24 hour detention time with its efficiency of 96.9% and 89.13%, respectively.

Influence of root-bed size on the response of tobacco to elevated CO2 as mediated by cytokinins

Science.gov (United States)

Schaz, Ulrike; Düll, Barbara; Reinbothe, Christiane; Beck, Erwin

2014-01-01

The extent of growth stimulation of C3 plants by elevated CO2 is modulated by environmental factors. Under optimized environmental conditions (high light, continuous water and nutrient supply, and others), we analysed the effect of an elevated CO2 atmosphere (700 ppm, EC) and the importance of root-bed size on the growth of tobacco. Biomass production was consistently higher under EC. However, the stimulation was overridden by root-bed volumes that restricted root growth. Maximum growth and biomass production were obtained at a root bed of 15 L at ambient and elevated CO2 concentrations. Starting with seed germination, the plants were strictly maintained under ambient or elevated CO2 until flowering. Thus, the well-known acclimation effect of growth to enhanced CO2 did not occur. The relative growth rates of EC plants exceeded those of ambient-CO2 plants only during the initial phases of germination and seedling establishment. This was sufficient for a persistently higher absolute biomass production by EC plants in non-limiting root-bed volumes. Both the size of the root bed and the CO2 concentration influenced the quantitative cytokinin patterns, particularly in the meristematic tissues of shoots, but to a smaller extent in stems, leaves and roots. In spite of the generally low cytokinin concentrations in roots, the amounts of cytokinins moving from the root to the shoot were substantially higher in high-CO2 plants. Because the cytokinin patterns of the (xylem) fluid in the stems did not match those of the shoot meristems, it is assumed that cytokinins as long-distance signals from the roots stimulate meristematic activity in the shoot apex and the sink leaves. Subsequently, the meristems are able to synthesize those phytohormones that are required for the cell cycle. Root-borne cytokinins entering the shoot appear to be one of the major control points for the integration of various environmental cues into one signal for optimized growth. PMID:24790131

Continuous processing of recombinant proteins: Integration of inclusion body solubilization and refolding using simulated moving bed size exclusion chromatography with buffer recycling.

Science.gov (United States)

Wellhoefer, Martin; Sprinzl, Wolfgang; Hahn, Rainer; Jungbauer, Alois

2013-12-06

An integrated process which combines continuous inclusion body dissolution with NaOH and continuous matrix-assisted refolding based on closed-loop simulated moving bed size exclusion chromatography was designed and experimentally evaluated at laboratory scale. Inclusion bodies from N(pro) fusion pep6His and N(pro) fusion MCP1 from high cell density fermentation were continuously dissolved with NaOH, filtered and mixed with concentrated refolding buffer prior to refolding by size exclusion chromatography (SEC). This process enabled an isocratic operation of the simulated moving bed (SMB) system with a closed-loop set-up with refolding buffer as the desorbent buffer and buffer recycling by concentrating the raffinate using tangential flow filtration. With this continuous refolding process, we increased the refolding and cleavage yield of both model proteins by 10% compared to batch dilution refolding. Furthermore, more than 99% of the refolding buffer of the raffinate could be recycled which reduced the buffer consumption significantly. Based on the actual refolding data, we compared throughput, productivity, and buffer consumption between two batch dilution refolding processes - one using urea for IB dissolution, the other one using NaOH for IB dissolution - and our continuous refolding process. The higher complexity of the continuous refolding process was rewarded with higher throughput and productivity as well as significantly lower buffer consumption compared to the batch dilution refolding processes. Copyright © 2013 Elsevier B.V. All rights reserved.

Staged fluidized-bed combustion and filter system

International Nuclear Information System (INIS)

Mei, J.S.; Halow, J.S.

1994-01-01

A staged fluidized-bed combustion and filter system are described for substantially reducing the quantity of waste through the complete combustion into ash-type solids and gaseous products. The device has two fluidized-bed portions, the first primarily as a combustor/pyrolyzer bed, and the second as a combustor/filter bed. The two portions each have internal baffles to define stages so that material moving therein as fluidized beds travel in an extended route through those stages. Fluidization and movement is achieved by the introduction of gases into each stage through a directional nozzle. Gases produced in the combustor/pyrolyzer bed are permitted to travel into corresponding stages of the combustor/filter bed through screen filters that permit gas flow but inhibit solids flow. Any catalyst used in the combustor/filter bed is recycled. The two beds share a common wall to minimize total volume of the system. A slightly modified embodiment can be used for hot gas desulfurization and sorbent regeneration. Either side-by-side rectangular beds or concentric beds can be used. The system is particularly suited to the processing of radioactive and chemically hazardous waste. 10 figures

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, ...

Semi-dry flue gas desulfurization using Ca(OH)2 in a fluidized bed reactor with bed materials

International Nuclear Information System (INIS)

Park, Young Oak; Roh, Hak Jae; Oh, Chang Sup; Kim, Yong Ha

2010-01-01

The main objective of present work is to reduce sulfur dioxide emission from power plant for the environment protection. The fluidized bed (FB) was used as the reactor with bed materials in a new semi-dry flue gas desulfurization (FGD) process to achieve high desulfurization efficiency (>98%). Fine powder of Ca(OH) 2 as sorbent and water were continuously fed separately to the bed reactor where bed materials (2 mm glass beads) were fluidized vigorously with flue gas (flow 720 Nm 3 / hr) using bench scale plant of stainless steel column. We have investigated different effects of water injection flow rate, Ca/ S molar ratio and weight of bed materials on SO 2 removal. The increments in the Ca/ S molar ratio and water injection flow rate have been resulted higher desulfurization efficiency with certain disadvantages such as higher sorbent cost and lower temperature of the treated flue gas, respectively. (author)

Remineralization of permeate water by calcite bed in the Daoura's plant (south of Morocco)

Science.gov (United States)

Biyoune, M. G.; Atbir, A.; Bari, H.; Hassnaoui, L.; Mongach, E.; Khadir, A.; Boukbir, L.; Bellajrou, R.; Elhadek, M.

2017-04-01

To face water shortage and to fight drought, the National office of Water and Electricity (ONEE) carried out a program aiming at constructing several desalination stations of seawater in the South of Morocco. However, the final product water after desalination (osmosis water) has turned out to be unbalanced and has an aggressive character. Therefore, a post-treatment of remineralization is necessary to recover the calco-carbonic equilibrium of water and to protect the distribution network from corrosion degradation. Thereby, our work aims to examine the performance of the remineralization used in Daoura plant by the calcite bed in the absence of carbon dioxide CO2 (without acidification), we have followed many parameters indicating the performance of this technique adopted such as pH, TAC (hydroxide, carbonate and bicarbonate content), Ca content, Langelier saturation index (LSI), Larson index (LR). The results obtained show that this technique adopted in Daoura plant brings to water back its entire calco-carbonic balance to measure up to the Moroccan standards of drinking water. Generally, the exploitation of the calcite bed technique for remineralization is simple, easy and it does not require any major efforts or precautions.

Survey of radionuclide emissions from coal-fired power plants and examination of impacts from a proposed circulating fluidized bed boiler power plant

International Nuclear Information System (INIS)

Steiner, C.P.; Militana, L.M.; Harvey, K.A.; Kinsey, G.D.

1995-01-01

This paper presents the results of a literature survey that examined radionuclide emissions from coal-fired power plants. Literature references from both the US and foreign countries are presented. Emphasis is placed on references from the US because the radionuclide emissions from coal-fired power plants are related to radionuclide concentrations in the coal, which vary widely throughout the world. The radionuclides were identified and quantified for various existing power plants reported in the literature. Applicable radionuclide emissions criteria discovered in the literature search were then applied to a proposed circulating fluidized bed boiler power plant. Based upon the derived radionuclide emission rates applied to the proposed power plant, an air quality modeling analysis was performed. The estimated ambient concentrations were compared to the most relevant existing regulatory ambient levels for radionuclides

Post-treatment of anaerobically degraded azo dye Acid Red 18 using aerobic moving bed biofilm process: Enhanced removal of aromatic amines

International Nuclear Information System (INIS)

Hosseini Koupaie, E.; Alavi Moghaddam, M.R.; Hashemi, S.H.

2011-01-01

Highlights: → Biofilm process was applied as post-treatment of anaerobically degraded an azo dye. → More than 65% of the dye total metabolites was completely mineralized. → Based on HPLC analysis, more than 80% of 1-naphthylamine-4-sulfonate was removed. → Inhibition of biofilm growth was increased with increasing the initial dye concentration. → Considerable porous morphology was observed in the SEM photographs of the biofilm. - Abstract: The application of aerobic moving bed biofilm process as post-treatment of anaerobically degraded azo dye Acid Red 18 was investigated in this study. The main objective of this work was to enhance removal of anaerobically formed the dye aromatic metabolites. Three separate sequential treatment systems were operated with different initial dye concentrations of 100, 500 and 1000 mg/L. Each treatment system consisted of an anaerobic sequencing batch reactor (An-SBR) followed by an aerobic moving bed sequencing batch biofilm reactor (MB-SBBR). Up to 98% of the dye decolorization and more than 80% of the COD removal occurred anaerobically. The obtained results suggested no significant difference in COD removal as well as the dye decolorization efficiency using three An-SBRs receiving different initial dye concentrations. Monitoring the dye metabolites through HPLC suggested that more than 80% of anaerobically formed 1-naphthylamine-4-sulfonate was completely removed in the aerobic biofilm reactors. Based on COD analysis results, at least 65-72% of the dye total metabolites were mineralized during the applied treatment systems. According to the measured biofilm mass and also based on respiration-inhibition test results, increasing the initial dye concentration inhibited the growth and final mass of the attached-growth biofilm in MB-SBBRs.

Influence of filling ratio and carrier type on organic matter removal in a moving bed biofilm reactor with pretreatment of electrocoagulation in wastewater treatment.

Science.gov (United States)

Lopez-Lopez, C; Martín-Pascual, J; González-Martínez, A; Calderón, K; González-López, J; Hontoria, E; Poyatos, J M

2012-01-01

At present, there is great concern about limited water resources and water quality, which require a more advanced technology. The Moving Bed Biofilm Reactor (MBBR) has been shown to be an efficient technology for removal of organic matter and nutrients in industrial and urban wastewater treatment. However, there are some pollutants which are more difficult to remove by biological processes, so this process can be improved with additional physical and chemical treatments such as electrocoagulation, which appears to be a promising technology in electrochemical treatments. In this research, urban wastewater was treated in an MBBR plant with an electrocoagulation pre-treatment. K1 from AnoxKaldnes and AQWISE ABC5 from Aqwise were the carriers studied under three different filling ratios (20, 35, and 50%). The experimental pilot plant had four bioreactors with 20 L of operation volume and a common feed tank with 100 L of operation volume. The movement of the carriers was generated by aeration and stirrer systems. Organic matter removal was studied by analysis of soluble chemical oxygen demand (sCOD). The maximum organic matter removal in this MBBR system was 65.8% ± 1.4% and 78.4% ± 0.1% for K1 and Aqwise ABC5 carriers, respectively. Moreover, the bacterial diversity of the biofilm was studied by temperature-gradient gel electrophoresis (TGGE) of PCR-amplified partial 16S rRNA genes. 20 prominent TGGE bands were successfully reamplified and sequenced, being the predominant population: β-Proteobacteria, α-Proteobacteria, and Actinobacteria.

A comparison of circulating fluidised bed combustion and gasification power plant technologies for processing mixtures of coal, biomass and plastic waste

International Nuclear Information System (INIS)

McIlveen-Wright, D.R.; Huang, Y.; McMullan, J.T.; Pinto, F.; Franco, C.; Gulyurtlu, I.; Armesto, L.; Cabanillas, A.; Caballero, M.A.; Aznar, M.P.

2006-01-01

Environmental regulations concerning emission limitations from the use of fossil fuels in large combustion plants have stimulated interest in biomass for electricity generation. The main objective of the present study was to examine the technical and economic viability of using combustion and gasification of coal mixed with biomass and plastic wastes, with the aim of developing an environmentally acceptable process to decrease their amounts in the waste stream through energy recovery. Mixtures of a high ash coal with biomass and/or plastic using fluidised bed technologies (combustion and gasification) were considered. Experiments were carried out in laboratory and pilot plant fluidised bed systems on the combustion and air/catalyst and air/steam gasification of these feedstocks and the data obtained were used in the techno-economic analyses. The experimental results were used in simulations of medium to large-scale circulating fluidised bed (CFB) power generation plants. Techno-economic analysis of the modelled CFB combustion systems showed efficiencies of around 40.5% (and around 46.5% for the modelled CFB gasification systems) when fuelled solely by coal, which were only minimally affected by co-firing with up to 20% biomass and/or wastes. Specific investments were found to be around $2150/kWe to $2400/kWe ($1350/kWe to $1450/kWe) and break-even electricity selling prices to be around $68/MWh to $78/MWh ($49/MWh to $54/MWh). Their emissions were found to be within the emission limit values of the large combustion plant directive. Fluidised bed technologies were found to be very suitable for co-firing coal and biomass and/or plastic waste and to offer good options for the replacement of obsolete or polluting power plants. (author)

Using autoregressive integrated moving average (ARIMA models to predict and monitor the number of beds occupied during a SARS outbreak in a tertiary hospital in Singapore

Directory of Open Access Journals (Sweden)

Earnest Arul

2005-05-01

Full Text Available Abstract Background The main objective of this study is to apply autoregressive integrated moving average (ARIMA models to make real-time predictions on the number of beds occupied in Tan Tock Seng Hospital, during the recent SARS outbreak. Methods This is a retrospective study design. Hospital admission and occupancy data for isolation beds was collected from Tan Tock Seng hospital for the period 14th March 2003 to 31st May 2003. The main outcome measure was daily number of isolation beds occupied by SARS patients. Among the covariates considered were daily number of people screened, daily number of people admitted (including observation, suspect and probable cases and days from the most recent significant event discovery. We utilized the following strategy for the analysis. Firstly, we split the outbreak data into two. Data from 14th March to 21st April 2003 was used for model development. We used structural ARIMA models in an attempt to model the number of beds occupied. Estimation is via the maximum likelihood method using the Kalman filter. For the ARIMA model parameters, we considered the simplest parsimonious lowest order model. Results We found that the ARIMA (1,0,3 model was able to describe and predict the number of beds occupied during the SARS outbreak well. The mean absolute percentage error (MAPE for the training set and validation set were 5.7% and 8.6% respectively, which we found was reasonable for use in the hospital setting. Furthermore, the model also provided three-day forecasts of the number of beds required. Total number of admissions and probable cases admitted on the previous day were also found to be independent prognostic factors of bed occupancy. Conclusion ARIMA models provide useful tools for administrators and clinicians in planning for real-time bed capacity during an outbreak of an infectious disease such as SARS. The model could well be used in planning for bed-capacity during outbreaks of other infectious

Using autoregressive integrated moving average (ARIMA) models to predict and monitor the number of beds occupied during a SARS outbreak in a tertiary hospital in Singapore.

Science.gov (United States)

Earnest, Arul; Chen, Mark I; Ng, Donald; Sin, Leo Yee

2005-05-11

The main objective of this study is to apply autoregressive integrated moving average (ARIMA) models to make real-time predictions on the number of beds occupied in Tan Tock Seng Hospital, during the recent SARS outbreak. This is a retrospective study design. Hospital admission and occupancy data for isolation beds was collected from Tan Tock Seng hospital for the period 14th March 2003 to 31st May 2003. The main outcome measure was daily number of isolation beds occupied by SARS patients. Among the covariates considered were daily number of people screened, daily number of people admitted (including observation, suspect and probable cases) and days from the most recent significant event discovery. We utilized the following strategy for the analysis. Firstly, we split the outbreak data into two. Data from 14th March to 21st April 2003 was used for model development. We used structural ARIMA models in an attempt to model the number of beds occupied. Estimation is via the maximum likelihood method using the Kalman filter. For the ARIMA model parameters, we considered the simplest parsimonious lowest order model. We found that the ARIMA (1,0,3) model was able to describe and predict the number of beds occupied during the SARS outbreak well. The mean absolute percentage error (MAPE) for the training set and validation set were 5.7% and 8.6% respectively, which we found was reasonable for use in the hospital setting. Furthermore, the model also provided three-day forecasts of the number of beds required. Total number of admissions and probable cases admitted on the previous day were also found to be independent prognostic factors of bed occupancy. ARIMA models provide useful tools for administrators and clinicians in planning for real-time bed capacity during an outbreak of an infectious disease such as SARS. The model could well be used in planning for bed-capacity during outbreaks of other infectious diseases as well.

Start-up and bacterial community compositions of partial nitrification in moving bed biofilm reactor.

Science.gov (United States)

Liu, Tao; Mao, Yan-Jun; Shi, Yan-Ping; Quan, Xie

2017-03-01

Partial nitrification (PN) has been considered as one of the promising processes for pretreatment of ammonium-rich wastewater. In this study, a kind of novel carriers with enhanced hydrophilicity and electrophilicity was implemented in a moving bed biofilm reactor (MBBR) to start up PN process. Results indicated that biofilm formation rate was higher on modified carriers. In comparison with the reactor filled with traditional carriers (start-up period of 21 days), it took only 14 days to start up PN successfully with ammonia removal efficiency and nitrite accumulation rate of 90 and 91%, respectively, in the reactor filled with modified carriers. Evident changes of spatial distributions and community structures had been detected during the start-up. Free-floating cells existed in planktonic sludge, while these microorganisms trended to form flocs in the biofilm. High-throughput pyrosequencing results indicated that Nitrosomonas was the predominant ammonia-oxidizing bacterium (AOB) in the PN system, while Comamonas might also play a vital role for nitrogen oxidation. Additionally, some other bacteria such as Ferruginibacter, Ottowia, Saprospiraceae, and Rhizobacter were selected to establish stable footholds. This study would be potentially significant for better understanding the microbial features and developing efficient strategies accordingly for MBBR-based PN operation.

Vegetation and plant food reconstruction of lowermost Bed II, Olduvai Gorge, using modern analogs.

Science.gov (United States)

Copeland, Sandi R

2007-08-01

Vegetation and plant foods for hominins of lowermost Bed II, Olduvai Gorge were modeled by examining vegetation in modern habitats in northern Tanzania (Lake Manyara, Ngorongoro, Serengeti) that are analogous to the paleolandscape in terms of climate, land forms, and soil types, as indicated by previous paleoenvironmental studies of Olduvai. Plant species in the modern habitats were identified in a series of sample plots, and those known to be eaten by modern humans, chimpanzees, or baboons were considered potentially edible for early hominins. Within the 50-80 kyr deposition of lowermost Bed II, periods of drier climate were characterized by low lake stands and a broad eastern lacustrine plain containing a mosaic of springs, marsh, woodland, and edaphic grassland. Based on results of this study, plant food diversity in each of those habitats was relatively low, but the mosaic nature of the area meant that hominins could reach several different habitat types within short distances, with access to potential plant foods including marsh plants, grass grains, roots, shrub fruits, edible parts from palms, leafy herbaceous plants, and Acacia pods, flowers, and gum. Based on Manyara analogs, a greater variety of plant foods, such as tree fruits (e.g., Ficus, Trichilia) and the roots and fruits of shrubs (e.g., Cordia, Salvadora) would be expected further east along the rivers in the lacustrine terrace and alluvial fans. Interfluves of the alluvial fans were probably less wooded and offered relatively fewer varieties of plant foods, but there is sparse paleoenvironmental evidence for the character of Olduvai's alluvial fans, making the choice of appropriate modern analogs difficult. In the western side of the basin, based on modern analogs in the Serengeti, riverine habitats provided the greatest variety of edible plant food species (e.g., Acacia, Grewia, Justicia). If the interfluves were grassland, then a large variety of potentially edible grasses and forbs were present

The characteristics of extracellular polymeric substances and soluble microbial products in moving bed biofilm reactor-membrane bioreactor.

Science.gov (United States)

Duan, Liang; Jiang, Wei; Song, Yonghui; Xia, Siqing; Hermanowicz, Slawomir W

2013-11-01

The characteristics of extracellular polymeric substances (EPS) and soluble microbial products (SMP) in conventional membrane bioreactor (MBR) and in moving bed biofilm reactor-membrane bioreactors (MBBR-MBR) were investigated in long-term (170 days) experiments. The results showed that all reactors had high removal efficiency of ammonium and COD, despite very different fouling conditions. The MBBR-MBR with media fill ratio of 26.7% had much lower total membrane resistance and no obvious fouling were detected during the whole operation. In contrast, MBR and MBBR-MBR with lower and higher media fill experienced more significant fouling. Low fouling at optimum fill ratio may be due to the higher percentage of small molecular size (100 kDa) of EPS and SMP in the reactor. The composition of EPS and SMP affected fouling due to different O-H bonds in hydroxyl functional groups, and less polysaccharides and lipids. Copyright © 2013 Elsevier Ltd. All rights reserved.

Bed mixing dryer for high moisture content fuels

Energy Technology Data Exchange (ETDEWEB)

Hulkkonen, S; Heinonen, O. [Imatran Voima Oy, Vantaa (Finland)

1998-12-31

Bed mixing dryer is a new type of fuel drying technology for fluidized bed combustion. The idea is to extract hot bed material from the fluidized bed and use it as a heat source for drying the fuel. Drying occurs at steam atmosphere which makes it possible to recover the latent heat of evaporation to process. This improves the thermal efficiency of the power plant process considerably, especially in combined heat and power applications. Imatran Voima Oy (IVO) has developed the Bed Mixing Dryer technology since early 1990s. The first pilot plant was built in 1994 to IVO`s Kuusamo peat and wood fired power plant. The capacity of the plant is 6 MW{sub e} and 20 MW of district heat. In Kuusamo the dryer is connected to a bubbling fluidized bed. Since it`s commissioning the dryer has been used successfully for about 3000 hours during the heating season in wintertime. The second application of the technology will be a demonstration project in Oerebro (S). IVO Power Engineering Ltd will supply in 1997 a dryer to Oerebro Energi`s peat, wood and coal fired CHP plant equipped with circulating fluidized bed boiler. The fuel to be dried is sawdust with fuel input of about 60 MW. In Kuusamo the dryer produces 3 MW of additional district heat and in Oerebro 6 MW. The fuels in Kuusamo are peat, saw dust and bark. In addition to the municipal heat production this type of drying technology has its benefits in pulp and paper industry processes. Disposal of paper mill sludges is becoming more difficult and costly which has resulted in need of alternative treatment. Drying of the sludge before combustion in a boiler for power production is an attractive option. At the moment IVO is carrying out several studies to apply the Bed Mixing Dryer in pulp and paper industry processes. Economy of drying the sludge looks promising

Bed mixing dryer for high moisture content fuels

Energy Technology Data Exchange (ETDEWEB)

Hulkkonen, S.; Heinonen, O. [Imatran Voima Oy, Vantaa (Finland)

1997-12-31

Bed mixing dryer is a new type of fuel drying technology for fluidized bed combustion. The idea is to extract hot bed material from the fluidized bed and use it as a heat source for drying the fuel. Drying occurs at steam atmosphere which makes it possible to recover the latent heat of evaporation to process. This improves the thermal efficiency of the power plant process considerably, especially in combined heat and power applications. Imatran Voima Oy (IVO) has developed the Bed Mixing Dryer technology since early 1990s. The first pilot plant was built in 1994 to IVO`s Kuusamo peat and wood fired power plant. The capacity of the plant is 6 MW{sub e} and 20 MW of district heat. In Kuusamo the dryer is connected to a bubbling fluidized bed. Since it`s commissioning the dryer has been used successfully for about 3000 hours during the heating season in wintertime. The second application of the technology will be a demonstration project in Oerebro (S). IVO Power Engineering Ltd will supply in 1997 a dryer to Oerebro Energi`s peat, wood and coal fired CHP plant equipped with circulating fluidized bed boiler. The fuel to be dried is sawdust with fuel input of about 60 MW. In Kuusamo the dryer produces 3 MW of additional district heat and in Oerebro 6 MW. The fuels in Kuusamo are peat, saw dust and bark. In addition to the municipal heat production this type of drying technology has its benefits in pulp and paper industry processes. Disposal of paper mill sludges is becoming more difficult and costly which has resulted in need of alternative treatment. Drying of the sludge before combustion in a boiler for power production is an attractive option. At the moment IVO is carrying out several studies to apply the Bed Mixing Dryer in pulp and paper industry processes. Economy of drying the sludge looks promising

Improvement of the performances of a tandem simulated moving bed chromatography by controlling the yield level of a key product of the first simulated moving bed unit.

Science.gov (United States)

Mun, Sungyong; Wang, Nien-Hwa Linda

2017-03-10

One of the trustworthy processes for ternary separation is a tandem simulated moving bed (SMB) process, which consists of two subordinate four-zone SMB units (Ring I and Ring II). To take full advantage of a tandem SMB as a means of recovering all three products with high purities and high economical efficiency, it is important to understand how the separation condition in Ring II is affected by that in Ring I, and further to reflect such point in the stage of designing a tandem SMB. In regard to such issue, it was clarified in this study that the Ring I factors affecting the Ring II condition could be represented by the yield level of a key product of Ring I (Y key RingI ). As the Y key RingI level became higher, the amount of the Ring I key-product that was reloaded into Ring II was reduced, which affected favorably the Ring II separation condition. On the other hand, the higher Y key RingI level caused a larger dilution for the stream from Ring I to Ring II, which affected adversely the Ring II separation condition. As a result, a minimum in the desorbent usage of a tandem SMB occurred at the Y key RingI level where the two aforementioned factors could be balanced with each other. If such an optimal Y key RingI level was adopted, the desorbent usage could be reduced by up to 25%. It was also found that as the throughput of a tandem SMB became higher, the factor related to the migration of the Ring I key-product into Ring II was more influential in the performances of a tandem SMB than the factor related to the dilution of the stream from Ring I to Ring II. Copyright © 2016 Elsevier B.V. All rights reserved.

Application of a Line Laser Scanner for Bed Form Tracking in a Laboratory Flume

Science.gov (United States)

de Ruijsscher, T. V.; Hoitink, A. J. F.; Dinnissen, S.; Vermeulen, B.; Hazenberg, P.

2018-03-01

A new measurement method for continuous detection of bed forms in movable bed laboratory experiments is presented and tested. The device consists of a line laser coupled to a 3-D camera, which makes use of triangulation. This allows to measure bed forms during morphodynamic experiments, without removing the water from the flume. A correction is applied for the effect of laser refraction at the air-water interface. We conclude that the absolute measurement error increases with increasing flow velocity, its standard deviation increases with water depth and flow velocity, and the percentage of missing values increases with water depth. Although 71% of the data is lost in a pilot moving bed experiment with sand, still high agreement between flowing water and dry bed measurements is found when a robust LOcally weighted regrESSion (LOESS) procedure is applied. This is promising for bed form tracking applications in laboratory experiments, especially when lightweight sediments like polystyrene are used, which require smaller flow velocities to achieve dynamic similarity to the prototype. This is confirmed in a moving bed experiment with polystyrene.

Fluidised bed combustion: a new route to power and heat from coal

Energy Technology Data Exchange (ETDEWEB)

Schilling, H D [Bergbau-Forschung G.m.b.H., Essen (Germany, F.R.)

1978-02-01

The functioning of fluidized-bed firings and their advantages with regard to SO/sub 2/ emissions are described. The principle of design of a fluidized-bed boiler and a gas/steam turbine power plant with fluidized-bed firing under pressure is outlined. The application and their economics in heat and power generation and marketing potential of fluidized-bed firings and their economics in heat and power generation is pointed out. The construction of waste-fired incinerators has already become possible, but there is still a lot of development work to be done until fluidized-bed firings can be used in central heatings, combined-cycle power plants, and large power plants.

Demonstration of a 1 MWe biomass power plant at USMC Base Camp Lejeune

International Nuclear Information System (INIS)

Cleland, J.; Purvis, C.R.

1997-01-01

A biomass energy conversion project is being sponsored by the U.S. Environmental Protection Agency (EPA) to demonstrate an environmentally and economically sound electrical power option for government installations, industrial sites, rural cooperatives, small municipalities, and developing countries. Under a cooperative agreement with EPA, Research Triangle Institute is initiating operation of the Camp Lejeune Energy from Wood (CLEW) biomass plant. Wood gasification combined with internal combustion engines was chosen because of (1) recent improvements in gas cleaning, (2) simple, economical operation for units less than 10 MW, and (3) the option of a clean, cheap fuel for the many existing facilities generating expensive electricity from petroleum fuels with reciprocating engines. The plant incorporates a downdraft, moving bed gasifier utilizing hogged waste wood from the Marine Corps Base at Camp Lejeune, NC. A moving bed bulk wood dryer and both spark ignition and diesel engines are included. Unique process design features are briefly described relative to the gasifier, wood drying, tar separation, and process control. A test plan for process optimization and demonstration of reliability, economics, and environmental impact is outlined. (author)

Fluid-bed methane proposed

Energy Technology Data Exchange (ETDEWEB)

1981-05-01

The first full scale plant for the production of methane from organic waste could be built in the next few years believes M.J. Nyns of the University of Louvain, Belgium, utilizing either expanded bed or fluidised bed systems, with more than one stage, in a continuous flow arrangement. Up to 8.0 m cubed gas/m cubed digester/day could be produced with residence times reduced to 34 hours.

Prediction of moving bed biofilm reactor (MBBR) performance for the treatment of aniline using artificial neural networks (ANN)

Energy Technology Data Exchange (ETDEWEB)

Delnavaz, M. [Tarbiat Modares University, Civil Engineering Department, Environmental Engineering Division, Tehran (Iran, Islamic Republic of); Ayati, B., E-mail: ayati_bi@modares.ac.ir [Tarbiat Modares University, Civil Engineering Department, Environmental Engineering Division, Tehran (Iran, Islamic Republic of); Ganjidoust, H. [Tarbiat Modares University, Civil Engineering Department, Environmental Engineering Division, Tehran (Iran, Islamic Republic of)

2010-07-15

In this study, the results of 1-year efficiency forecasting using artificial neural networks (ANN) models of a moving bed biofilm reactor (MBBR) for a toxic and hard biodegradable aniline removal were investigated. The reactor was operated in an aerobic batch and continuous condition with 50% by volume which was filled with light expanded clay aggregate (LECA) as carrier. Efficiency evaluation of the reactors was obtained at different retention time (RT) of 8, 24, 48 and 72 h with an influent COD from 100 to 4000 mg/L. Exploratory data analysis was used to detect relationships between the data and dependent evaluated one. The appropriate architecture of the neural network models was determined using several steps of training and testing of the models. The ANN-based models were found to provide an efficient and a robust tool in predicting MBBR performance for treating aromatic amine compounds.

River Bed Sediment Classification Using ADCP

Science.gov (United States)

Description of physical aquatic habitat in rivers often includes data describing distributions of water depth, velocity and bed material type. Water depth and velocity in streams deeper than about 1 m may be continuously mapped using an acoustic Doppler current profiler from a moving boat. Herein ...

Granular controls on the dispersion of bed load tracers

Science.gov (United States)

Jerolmack, D. J.; Martin, R. L.; Phillips, C. B.

2014-12-01

Coarse particles are transported in a river as bed load, i.e., they move in frequent contact with and are supported by the granular bed. This movement is typically intermittent and may be described by a series of steps are rests, the distributions of which determine particle dispersion. Laboratory and field studies of bed load tracer dispersion have reported sub- and super-diffusive behavior, both of which have been successfully reproduced with stochastic transport models. Although researchers have invoked heavy-tailed step lengths as the cause of anomalous dispersion, most observations report thin-tailed distributions. Little attention has been paid to rest periods, and stochastic transport models have not been connected to the underlying mechanics of particle motion. Based on theoretical and experimental evidence, we argue that step lengths are thin-tailed and do not control the longterm dispersion of bed load tracers; they are determined by momentum balance between the fluid and solid. Using laboratory experiments with both marbles and natural sediments, we demonstrate that the rest time distribution is power law, and argue that this distribution controls asymptotic dispersion. Observed rest times far exceed any hydrodynamic timescale. Experiments reveal that rest times of deposited particles are governed by fluctuations in river bed elevation; in particular, the return time for the bed to scour to the base of a deposited particle. Stochastic fluctuations in bed elevation are describable by an Ornstein-Uhlenbeck (mean-reverting random walk) model that contains two parameters, which we show are directly related to the granular shear rate and range of bed elevation fluctuations, respectively. Combining these results with the theory of asymmetric random walks (particles only move downstream), we predict superdiffusive behavior that is in quantitative agreement with our observations of tracer dispersion in a natural river.

Fluidized bed incineration of transuranic contaminated waste

International Nuclear Information System (INIS)

Ziegler, D.L.; Johnson, A.J.

1978-01-01

A 9 kg/hr pilot scale fluidized bed incinerator is now being used for burning various types of radioactive waste at Rocky Flats Plant. General solid combustible waste containing halogenated materials is burned in a fluidized bed of sodium carbonate for in situ neutralization of thermally generated acidic gases. A variety of other production related materials has been burned in the incinerator, including ion exchange resin, tributyl phosphate solutions, and air filters. Successful operation of the pilot plant incinerator has led to the design and construction of a production site unit to burn 82 kg/hr of plant generated waste. Residues from incinerator operations will be processed into glass buttons utilizing a vitrification plant now under development

Sequencing treatment of industrial wastewater with ultraviolet/H2O2 advanced oxidation and moving bed bioreactor

Directory of Open Access Journals (Sweden)

Mohammad Mehdi Mehrabani Ardekani

2015-01-01

Full Text Available Aims: The main purpose of this study was to determine the efficiency of a sequencing treatment including ultraviolet (UV/H 2 O 2 oxidation followed by a moving bed bioreactor (MBBR. Materials and Methods: Effect of solution pH, reaction time, and H 2 O 2 concentration were investigated for an industrial wastewater sample. The effluent of the advanced oxidation processes unit was introduced to the MBBR operated for three hydraulic retention times of 4, 8, and 12 h. Results: The optimum condition for industrial wastewater treatment via advanced oxidation was solution pH: 7, H 2 O 2 dose: 1000 mg/L and 90 min reaction time. These conditions led to 74.68% chemical oxygen demand (COD removal and 66.15% biochemical oxygen demand (BOD 5 removal from presedimentation step effluent that initially had COD and BOD 5 contents of 4,400 and 1,950 mg/L, respectively. Conclusion: Combination of UV/H 2 O 2 advanced oxidation with MBBR could result in effluents that meet water quality standards for discharge to receiving waters.

Laboratory and pilot-plant studies on the conversion of uranyl nitrate hexahydrate to UF6 by fluidized-bed processes

International Nuclear Information System (INIS)

Youngblood, E.L.; Urza, I.J.; Cathers, G.I.

1977-06-01

This report describes laboratory and pilot-plant studies on the conversion of uranyl nitrate hexahydrate (UNH) to UF 6 and on purification of the UF 6 . Experimental laboratory studies on the removal of residual nitrate from uranium trioxide (UO 3 ) calcine and the fluorination of technetium and subsequent sorption on MgF 2 were conducted to support the pilot-plant work. Two engineering-scale pilot plants utilizing fluidized-bed processes were constructed for equipment and process testing of the calcination of UNH to UO 3 and the direct fluorination of UO 3 to UF 6

Stabilizing effect of plasma discharge on bubbling fluidized granular bed

International Nuclear Information System (INIS)

Hu Mao-Bin; Dang Sai-Chao; Ma Qiang; Xia Wei-Dong

2015-01-01

Fluidized beds have been widely used for processing granular materials. In this paper, we study the effect of plasma on the fluidization behavior of a bubbling fluidized bed with an atmospheric pressure plasma discharger. Experiment results show that the bubbling fluidized bed is stabilized with the discharge of plasma. When the discharge current reaches a minimum stabilization current C ms , air bubbles in the bed will disappear and the surface fluctuation is completely suppressed. A simplified model is proposed to consider the effect of electric Coulomb force generated by the plasma. It is found that the Coulomb force will propel the particles to move towards the void area, so that the bubbling fluidized bed is stabilized with a high enough plasma discharge. (paper)

Thermal treatment of high-caloric waste in fluidized bed incineration plants in Austria

International Nuclear Information System (INIS)

Ragossnig, A.M.

2001-05-01

The importance of thermal treatment of waste and residues in Austria is expected to rise due to the current changes of the legal situation in waste management. Assessing the rank order of different thermal treatment processes for waste management it has been shown that - especially caused by the rising importance of the mechanical treatment step in the mechanical-biological residual waste treatment and the subsequent necessity of the thermal treatment of a high-caloric preprocessed waste stream - the importance of the fluidized bed technology will increase. The main advantages are the high existing capacities as well as the flexibility of this technology in regard of fuel properties and further on the fact of the lacking influence of the ash towards the quality of a product. This is true although the thermal treatment in fluidized bed incinerators requires some processing of the waste. This doctoral thesis also contains a thorough physical and chemical characterization of various waste fuels - especially those which have been used during full scale incineration experiments. This characterization includes a comparison with fossil fuel. The practical part contains the documentation and balancing of full scale incineration experiments. A comparison of a reference experiment with experiments when waste fuel has been thermally utilized showed that a significant increase of emissions to the atmosphere has not been observed. Based on the incineration experiments conclusions in regard of waste fuels as well as different categories of thermal treatment plants are being stated. Finally, a recommendation of the assignation of various waste streams to different categories of thermal treatment plants is being made. (author)

Research on the power consumption of the biological stages of wastewater treatment plant; Untersuchung ueber den Stromverbrauch biologischer Reinigungsverfahren auf Klaeranlagen

Energy Technology Data Exchange (ETDEWEB)

Kempf, S.; Sigel, O.

2006-07-01

The largest electricity consumption in municipal sewage treatment plants occurs during biological treatment. This fact has been the motivation for a closer look at the electricity consumption of three biological treatment processes that will be applied more frequently in the future. The wastewater treatment plants in Lyss (Fixed Bed Biological Reactor), Wohlen (Moving Bed Biological Reactor), and Waedenswil (Membrane Biological Reactor submerged in an activated sludge process) provided the basis for this analysis, which was done both in absolute terms as well as in relation to each plant's loading. The specific energy consumption of the Fixed Bed Reactor, averaging 20 - 25 kWh/p.e. per annum (p.e. = person equivalent), is comparable to the one of a conventional activated sludge process (benchmark/standard value = 23 kWh/p.e. per annum; optimal value 18 kWh/p.e. per annum). The Moving Bed Reactor uses less than 30 kWh/p.e per annum when working at or close to full capacity, and more than 40 kWh/p.e. per annum at low fill. The Membrane Biological Reactor submerged in an activated sludge process shows the highest specific energy consumption values (> 40 kWh/p.e. per annum). In order to be able to run the biological treatment at optimal electricity consumption levels, the plants should be designed in such a way as to automatically run on partial or intermittent mode in times of low waste load. Further implementation of these new biological purification processes will lead to an increase in electricity consumption unless the significant energy savings potential wastewater treatment plants still offer is tapped. In order to be able to exploit this potential, electricity consumption has to be considered as of equal relevance as treated effluent quality. (author)

Physicochemical characteristics and microbial community evolution of biofilms during the start-up period in a moving bed biofilm reactor.

Science.gov (United States)

Zhu, Yan; Zhang, Yan; Ren, Hong-Qiang; Geng, Jin-Ju; Xu, Ke; Huang, Hui; Ding, Li-Li

2015-03-01

This study aimed to investigate biofilm properties evolution coupled with different ages during the start-up period in a moving bed biofilm reactor system. Physicochemical characteristics including adhesion force, extracellular polymeric substances (EPS), morphology as well as volatile solid and microbial community were studied. Results showed that the formation and development of biofilms exhibited four stages, including (I) initial attachment and young biofilm formation, (II) biofilms accumulation, (III) biofilm sloughing and updating, and (IV) biofilm maturation. During the whole start-up period, adhesion force was positively and significantly correlated with the contents of EPS, especially the content of polysaccharide. In addition, increased adhesion force and EPS were beneficial for biofilm retention. Gram-negative bacteria mainly including Sphaerotilus, Zoogloea and Haliscomenobacter were predominant in the initial stage. Actinobacteria was beneficial to resist sloughing. Furthermore, filamentous bacteria were dominant in maturation biofilm. Copyright © 2015 Elsevier Ltd. All rights reserved.

Deep geologic disposal of mixed waste in bedded salt: The Waste Isolation Pilot Plant

International Nuclear Information System (INIS)

Rempe, N.T.

1993-01-01

Mixed waste (i.e., waste that contains both chemically hazardous and radioactive components) poses a moral, political, and technical challenge to present and future generations. But an international consensus is emerging that harmful byproducts and residues can be permanently isolated from the biosphere in a safe and environmentally responsible manner by deep geologic disposal. To investigate and demonstrate such disposal for transuranic mixed waste, derived from defense-related activities, the US Department of Energy has prepared the Waste Isolation Pilot Plant (WIPP) near Carlsbad, New Mexico. This research and development facility was excavated approximately at the center of a 600 m thick sequence of salt (halite) beds, 655 m below the surface. Proof of the long-term tectonic and hydrological stability of the region is supplied by the fact that these salt beds have remained essentially undisturbed since they were deposited during the Late Permian age, approximately 225 million years ago. Plutonium-239, the main radioactive component of transuranic mixed waste, has a half-life of 24,500 years. Even ten half-lives of this isotope - amounting to about a quarter million years, the time during which its activity will decline to background level represent only 0.11 percent of the history of the repository medium. Therefore, deep geologic disposal of transuranic mixed waste in Permian bedded salt appears eminently feasible

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.

Gas Reactor International Cooperative program. Pebble bed reactor plant: screening evaluation. Volume 3. Appendix A. Equipment list

International Nuclear Information System (INIS)

1979-11-01

This report consists of three volumes which describe the design concepts and screening evaluation for a 3000 MW(t) Pebble Bed Reactor Multiplex Plant (PBR-MX). The Multiplex plant produces both electricity and transportable chemical energy via the thermochemical pipeline (TCP). The evaluation was limited to a direct cycle plant which has the steam generators and steam reformers in the primary circuit. Volume 1 reports the overall plant and reactor system and was prepared by the General Electric Company. Core scoping studies were performed which evaluated the effects of annular and cylindrical core configurations, radial blanket zones, burnup, and ball heavy metal loadings. The reactor system, including the PCRV, was investigated for both the annular and cylindrical core configurations. Volume 3 is an Appendix containing the equipment list for the plant and was also prepared by United Engineers and Constructors, Inc. It tabulates the major components of the plant and describes each in terms of quantity, type, orientation, etc., to provide a basis for cost estimation

Thermal denitrification of evaporators concentrates in reactor with fluidized bed

International Nuclear Information System (INIS)

Brugnot, C.

1993-11-01

As part of the treatments of liquid wastes coming from the Marcoule reprocessing plant, the study of a thermal denitrification process for evaporator concentrates has been chosen by the CEA/CEN Cadarache: the fluidized-bed calcination. This work presents the study of a calcination pilot-plant for wastes with a very high sodium nitrate content. After a reactional analysis carried out in a thermobalance on samples which are representative of the fluidized-bed compounds, the perfecting of many of the plant parameters - such as the solution injection system - was carried out on a scale-model at first. Then, it was verified on the pilot-plant, and some experiments have been carried out. A mathematical model for the particle growth inside the fluidized-bed is proposed. (author). 179 refs., 65 figs., 23 tabs

Agglomeration of bed material: Influence on efficiency of biofuel fluidized bed boiler

Directory of Open Access Journals (Sweden)

Ryabov Georgy A.

2003-01-01

Full Text Available The successful design and operation of a fluidized bed combustor requires the ability to control and mitigate ash-related problems. The main ash-related problem of biomass filing boiler is agglomeration. The fluidized bed boiler with steam capacity of 66 t/h (4 MPa, 440 °C was started up at the Arkhangelsk Paper-Pi dp-Plant in 2001. This boiler was manufactured by the Russian companies "Energosofin" and "Belenergomash" and installed instead of the existing boiler with mechanical grate. Some constructional elements and steam drum of existing boiler remained unchanged. The primary air fan was installed past the common air fan, which supply part of the air into 24 secondary airports. First operating period shows that the bed material is expanded and then operator should increase the primary air rate, and the boiler efficiency dramatically decreases. Tills paper presents some results of our investigations of fuel, bed and fly ash chemical compositions and other characteristics. Special experiments were carried out to optimize the bed drain flow rate. The influence of secondly air supply improvement on mixing with the main flow and boiler efficiency are given.

1 The Effect of Camber Bed Drainage

African Journals Online (AJOL)

User

The Effect of Camber Bed Drainage Landforms on Soil. Nutrient Distribution and Grain Yield of Maize on the Vertisols ... The Vertisols of the Accra Plains of Ghana are water logged after significant rainfall ... Excess application of 15-15-15 NPK and sulphate of ammonia fertilizers (150% .... beds, before planting and nutrient.

FY 1991 report on the results of the development of an entrained bed coal gasification power plant. Part 2. Support study for the development of an entrained bed coal gasification power plant (Summarization of the operation study); 1991 nendo seika hokokusho. Funryusho sekitan gaska hatsuden plant kaihatsu (Funryusho sekitan gaska hatsuden plant kaihatsu no shien kenkyu) - Sono 2. Unten kenkyu sokatsu hen

Energy Technology Data Exchange (ETDEWEB)

NONE

1992-04-01

The paper summarized the results of the following tests on a 40 t/d pilot plant which were conducted as the support study for the development of an entrained bed coal gasification power plant: dry desulfurization test, dry dedusting test, high-temperature NOx gas combustion test (gas turbine element test). In the dry desulfurization test, tested were the operational automation and monitoring technology, performance of desulfurization, characteristics of load response, sulfur recovery, etc. In the dry dedusting test, tested were the filter medium/dust separation, powder level meter, continuous dust densitometer, operational automation, characteristics of partial load/load response, improvement of filtration materials, test on characteristics of air conveyance, etc. In the high-temperature low-NOx gas combustion test (gas turbine element test), the following were conducted: examination of the test method of gas turbine materials, inspection/examination of the corrosion of gas turbine combustion test device, inspection/examination of the internal corrosion of the stationary blade for gas turbine deposit test, inspection/examination of gasification system. The results of these support studies were reflected one after another in the project on the development of an entrained bed coal gasification power plant. (NEDO)

Numerical modeling of the vertical hydrofluorination zone in the moving bed furnace for the production of UF{sub 4}

Energy Technology Data Exchange (ETDEWEB)

Jourde, J.; Patisson, F.; Ablitzer, D. [Ecole des Mines, Nancy (France). Lab. de Science et Genie des Materiaux Metalliques; Houzelot, J.L. [Ecole des Mines, Nancy (France). Lab. des Sciences du Genie Chimique

1996-12-31

Uranium tetrafluoride UF{sub 4} is produced in the moving bed furnace, a reactor in which solid- and gas counterflow. Due to the highly exothermic nature of the chemical reactions involved, the-reactor operation requires a careful temperature control. To provide operators with an appropriate tool for the predictive simulation, optimization and control of the process an overall numerical model of the furnace has been developed. This article describes the part of the model concerning the vertical hydrofluorination zone. The differential equations representing the mass, energy and momentum balances are solved using the finite volume method. The physicochemical parameters necessary for the calculation are detailed. The rate of the main reaction, the hydrofluorination of UO{sub 2}, has been determined with the aid of a specific kinetic model. The computed parameters, namely the temperature and solid and gas compositions, are visualized in the form of isovalue maps. The initial results reveal the influence of a thermodynamic limitation of the reaction at temperatures higher than 650 K. (author)

Numerical modeling of the vertical hydrofluorination zone in the moving bed furnace for the production of UF{sub 4}

Energy Technology Data Exchange (ETDEWEB)

Jourde, J; Patisson, F; Ablitzer, D [Ecole des Mines, Nancy (France). Lab. de Science et Genie des Materiaux Metalliques; Houzelot, J L [Ecole des Mines, Nancy (France). Lab. des Sciences du Genie Chimique

1997-12-31

Uranium tetrafluoride UF{sub 4} is produced in the moving bed furnace, a reactor in which solid- and gas counterflow. Due to the highly exothermic nature of the chemical reactions involved, the-reactor operation requires a careful temperature control. To provide operators with an appropriate tool for the predictive simulation, optimization and control of the process an overall numerical model of the furnace has been developed. This article describes the part of the model concerning the vertical hydrofluorination zone. The differential equations representing the mass, energy and momentum balances are solved using the finite volume method. The physicochemical parameters necessary for the calculation are detailed. The rate of the main reaction, the hydrofluorination of UO{sub 2}, has been determined with the aid of a specific kinetic model. The computed parameters, namely the temperature and solid and gas compositions, are visualized in the form of isovalue maps. The initial results reveal the influence of a thermodynamic limitation of the reaction at temperatures higher than 650 K. (author)

MIT pebble bed reactor project

Energy Technology Data Exchange (ETDEWEB)

Kadak, Andrew C. [Massachusetts Institute of Technology, Cambridge (United States)

2007-03-15

The conceptual design of the MIT modular pebble bed reactor is described. This reactor plant is a 250 Mwth, 120 Mwe indirect cycle plant that is designed to be deployed in the near term using demonstrated helium system components. The primary system is a conventional pebble bed reactor with a dynamic central column with an outlet temperature of 900 C providing helium to an intermediate helium to helium heat exchanger (IHX). The outlet of the IHX is input to a three shaft horizontal Brayton Cycle power conversion system. The design constraint used in sizing the plant is based on a factory modularity principle which allows the plant to be assembled 'Lego' style instead of constructed piece by piece. This principle employs space frames which contain the power conversion system that permits the Lego-like modules to be shipped by truck or train to sites. This paper also describes the research that has been conducted at MIT since 1998 on fuel modeling, silver leakage from coated fuel particles, dynamic simulation, MCNP reactor physics modeling and air ingress analysis.

MIT pebble bed reactor project

International Nuclear Information System (INIS)

Kadak, Andrew C.

2007-01-01

The conceptual design of the MIT modular pebble bed reactor is described. This reactor plant is a 250 Mwth, 120 Mwe indirect cycle plant that is designed to be deployed in the near term using demonstrated helium system components. The primary system is a conventional pebble bed reactor with a dynamic central column with an outlet temperature of 900 C providing helium to an intermediate helium to helium heat exchanger (IHX). The outlet of the IHX is input to a three shaft horizontal Brayton Cycle power conversion system. The design constraint used in sizing the plant is based on a factory modularity principle which allows the plant to be assembled 'Lego' style instead of constructed piece by piece. This principle employs space frames which contain the power conversion system that permits the Lego-like modules to be shipped by truck or train to sites. This paper also describes the research that has been conducted at MIT since 1998 on fuel modeling, silver leakage from coated fuel particles, dynamic simulation, MCNP reactor physics modeling and air ingress analysis

Improvement of poly-γ-glutamic acid biosynthesis in a moving bed biofilm reactor by Bacillus subtilis NX-2.

Science.gov (United States)

Jiang, Yongxiang; Tang, Bao; Xu, Zongqi; Liu, Kun; Xu, Zheng; Feng, Xiaohai; Xu, Hong

2016-10-01

The production of poly-γ-glutamic acid (γ-PGA) by Bacillus subtilis NX-2 using a moving bed biofilm reactor (MBBR) system was tested for the first time in this study. Polypropylene TL-2 was chosen as a suitable carrier, and γ-PGA concentration of 42.7±0.86g/L and productivity of 0.59±0.06g/(Lh) were obtained in batch fermentation. After application of the strategy of dissolved oxygen (DO)-stat feeding, higher γ-PGA concentration and productivity were achieved than with glucose feedback feeding. Finally, the repeated fed-batch cultures implemented in the MBBR system showed high stability, and the maximal γ-PGA concentration and productivity of 74.2g/L and 1.24g/(Lh) were achieved, respectively. In addition, the promotion of oxygen transfer by an MBBR carrier was well explained by a computational fluid dynamics (CFD) simulation. These results suggest that an MBBR system could be applied to large-scale γ-PGA production. Copyright © 2016 Elsevier Ltd. All rights reserved.

The Importance of Splat Events to the Spatiotemporal Structure of Near-Bed Fluid Velocity and Bed Load Motion Over Bed Forms: Laboratory Experiments Downstream of a Backward Facing Step

Science.gov (United States)

Leary, K. C. P.; Schmeeckle, M. W.

2017-12-01

Flow separation/reattachment on the lee side of alluvial bed forms is known to produce a complex turbulence field, but the spatiotemporal details of the associated patterns of bed load sediment transported remain largely unknown. Here we report turbulence-resolving, simultaneous measurements of bed load motion and near-bed fluid velocity downstream of a backward facing step in a laboratory flume. Two synchronized high-speed video cameras simultaneously observed bed load motion and the motion of neutrally buoyant particles in a laser light sheet 6 mm above the bed at 250 frames/s downstream of a 3.8 cm backward facing step. Particle Imaging Velocimetry (PIV) and Acoustic Doppler Velocimetry (ADV) were used to characterize fluid turbulent patterns, while manual particle tracking techniques were used to characterize bed load transport. Octant analysis, conducted using ADV data, coupled with Markovian sequence probability analysis highlights differences in the flow near reattachment versus farther downstream. Near reattachment, three distinct flow patterns are apparent. Farther downstream we see the development of a dominant flow sequence. Localized, intermittent, high-magnitude transport events are more apparent near flow reattachment. These events are composed of streamwise and cross-stream fluxes of comparable magnitudes. Transport pattern and fluid velocity data are consistent with the existence of permeable "splat events," wherein a volume of fluid moves toward and impinges on the bed (sweep) causing a radial movement of fluid in all directions around the point of impingement (outward interaction). This is congruent with flow patterns, identified with octant analysis, proximal to flow reattachment.

Advances in fluidized bed technologies

International Nuclear Information System (INIS)

Mutanen, K.

1992-01-01

Atmospheric fluidized bed combustion (AFBC) has advanced into industrial cogeneration and utility-scale electric generation. During the 1980's AFBC became the dominant technology in the United States for power generation systems fired with solid fuels. Development of pressurized fluidized bed combustion/gasification (PFB/G) has grown rapidly from small bench-scale rigs to large pilot and demonstration plants. AFBC as large as 160 MWe in capacity are now in operation, while pressurized combustion systems generating 80 MWe have started up two years ago. The major driving forces behind development of fluidized bed technologies are all the time strictening emission control regulations, need for fuel flexibility, repowering of older power plants and need for higher efficiency in electricity generation. Independent power producers (IPP) and cogenerators were the first ones in the United States who accepted AFBC for wide commercial use. Their role will be dominant in the markets of the 1990's also. Developers of AFBC systems are working on designs that reduce investment costs, decrease emissions and offer even higher reliability and availability in utility-scale applications while developers of PFBC/G work on designs that increase plant efficiencies, allow modular construction, decrease emissions further and reduce the cost of generating power. This paper presents technological background, commercial status, boiler performance, emissions and future developments for both AFBC and PFBC/G systems

Moving-Bed Process for Residue Hydrotreating Procédé à lit mobile pour l'hydrotraitement des résidus

Directory of Open Access Journals (Sweden)

Euzen J. P.

2006-11-01

Full Text Available A lot of chemical, petrochemical or refining processes require contact between three phases : a liquid feed, a gaseous reactant and a solid catalyst. Frequently, the catalyst activity is reduced by poisoning of active sites or coke deposits. This is especially the case with the processes used in heavy residual oils hydrotreating. As the catalyst life is reduced, the substitution or regeneration of the inactive catalyst is frequently necessary. Various solutions, such, as fixed beds used with swing reactors, fluidized beds, or moving beds with down flow of the catalyst and co-current or counter-current of the feed, can be proposed to perform this task with a minimum of time and production losses. A theoretical comparison between the performances of the various technologies has been made by means of a detailed simulation of the behaviour of each of these catalytic beds over a long period. Of course, in the models, some assumptions are necessary, like the ideal fluid and solids flows. Nevertheless, the problem remains complex because hydrodynamic, kinetic, catalyst deactivation, or thermal effects occur simultaneously, within the particules and/or in the bed as a whole. Various pilot plant data are of course used in order to build the kinetic part of the models. This comparison shows a marked advantage for the moving bed with counter-current flow between feed and catalyst owing to the systematic optimum use of the catalyst potential. Consequently, a series of experiments was made on various sized cold mockups designed to simulate counter-current movind beds. These experiments were necessary to demonstrate the feasability of the process, to specify the relations among gas and liquid superficial velocities, particles and fluids properties, and hydrodynamic regimes, and to develop the scale-up rules. The main goal is to secure a uniform distribution of the two fluids through out the whole bed of catalyst, and at the same time a regular progression of

Laboratory and pilot-plant studies on the conversion of uranyl nitrate hexahydrate to UF/sub 6/ by fluidized-bed processes

Energy Technology Data Exchange (ETDEWEB)

Youngblood, E.L.; Urza, I.J.; Cathers, G.I.

1977-06-01

This report describes laboratory and pilot-plant studies on the conversion of uranyl nitrate hexahydrate (UNH) to UF/sub 6/ and on purification of the UF/sub 6/. Experimental laboratory studies on the removal of residual nitrate from uranium trioxide (UO/sub 3/) calcine and the fluorination of technetium and subsequent sorption on MgF/sub 2/ were conducted to support the pilot-plant work. Two engineering-scale pilot plants utilizing fluidized-bed processes were constructed for equipment and process testing of the calcination of UNH to UO/sub 3/ and the direct fluorination of UO/sub 3/ to UF/sub 6/.

Clinical physiology of bed rest

Science.gov (United States)

Greenleaf, John E.

1993-01-01

Maintenance of optimal health in humans requires the proper balance between exercise, rest, and sleep as well as time in the upright position. About one-third of a lifetime is spent sleeping; and it is no coincidence that sleeping is performed in the horizontal position, the position in which gravitational influence on the body is minimal. Although enforced bed rest is necessary for the treatment of some ailments, in some cases it has probably been used unwisely. In addition to the lower hydrostatic pressure with the normally dependent regions of the cardiovascular system, body fuid compartments during bed rest in the horizontal body position, and virtual elimination of compression on the long bones of the skeletal system during bed rest (hypogravia), there is often reduction in energy metabolism due to the relative confinement (hypodynamia) and alteration of ambulatory circadian variations in metabolism, body temperature, and many hormonal systems. If patients are also moved to unfamiliar surroundings, they probably experience some feelings of anxiety and some sociopsychological problems. Adaptive physiological responses during bed rest are normal for that environment. They are attempts by the body to reduce unnecessary energy expenditure, to optimize its function, and to enhance its survival potential. Many of the deconditioning responses begin within the first day or two of bed rest; these early responses have prompted physicians to insist upon early resumption of the upright posture and ambulation of bedridden patients.

ECONOMICS AND FEASIBILITY OF RANKINE CYCLE IMPROVEMENTS FOR COAL FIRED POWER PLANTS

Energy Technology Data Exchange (ETDEWEB)

Richard E. Waryasz; Gregory N. Liljedahl

2004-09-08

ALSTOM Power Inc.'s Power Plant Laboratories (ALSTOM) has teamed with the U.S. Department of Energy National Energy Technology Laboratory (DOE NETL), American Electric Company (AEP) and Parsons Energy and Chemical Group to conduct a comprehensive study evaluating coal fired steam power plants, known as Rankine Cycles, equipped with three different combustion systems: Pulverized Coal (PC), Circulating Fluidized Bed (CFB), and Circulating Moving Bed (CMB{trademark}). Five steam cycles utilizing a wide range of steam conditions were used with these combustion systems. The motivation for this study was to establish through engineering analysis, the most cost-effective performance potential available through improvement in the Rankine Cycle steam conditions and combustion systems while at the same time ensuring that the most stringent emission performance based on CURC (Coal Utilization Research Council) 2010 targets are met: > 98% sulfur removal; < 0.05 lbm/MM-Btu NO{sub x}; < 0.01 lbm/MM-Btu Particulate Matter; and > 90% Hg removal. The final report discusses the results of a coal fired steam power plant project, which is comprised of two parts. The main part of the study is the analysis of ten (10) Greenfield steam power plants employing three different coal combustion technologies: Pulverized Coal (PC), Circulating Fluidized Bed (CFB), and Circulating Moving Bed (CMB{trademark}) integrated with five different steam cycles. The study explores the technical feasibility, thermal performance, environmental performance, and economic viability of ten power plants that could be deployed currently, in the near, intermediate, and long-term time frame. For the five steam cycles, main steam temperatures vary from 1,000 F to 1,292 F and pressures from 2,400 psi to 5,075 psi. Reheat steam temperatures vary from 1,000 F to 1,328 F. The number of feedwater heaters varies from 7 to 9 and the associated feedwater temperature varies from 500 F to 626 F. The main part of the

Treatment of petroleum refinery wastewater using a sequential anaerobic-aerobic moving-bed biofilm reactor system based on suspended ceramsite.

Science.gov (United States)

Lu, Mang; Gu, Li-Peng; Xu, Wen-Hao

2013-01-01

In this study, a novel suspended ceramsite was prepared, which has high strength, optimum density (close to water), and high porosity. The ceramsite was used to feed a moving-bed biofilm reactor (MBBR) system with an anaerobic-aerobic (A/O) arrangement to treat petroleum refinery wastewater for simultaneous removal of chemical oxygen demand (COD) and ammonium. The hydraulic retention time (HRT) of the anaerobic-aerobic MBBR system was varied from 72 to 18 h. The anaerobic-aerobic system had a strong tolerance to shock loading. Compared with the professional emission standard of China, the effluent concentrations of COD and NH3-N in the system could satisfy grade I at HRTs of 72 and 36 h, and grade II at HRT of 18 h. The average sludge yield of the anaerobic reactor was estimated to be 0.0575 g suspended solid/g CODremoved. This work demonstrated that the anaerobic-aerobic MBBR system using the suspended ceramsite as bio-carrier could be applied to achieving high wastewater treatment efficiency.

Simulation assessment of continuous simulating moving bed chromatography process with partial feed and new strategy with partial feed

Directory of Open Access Journals (Sweden)

H. Khan

2009-09-01

Full Text Available Partial Feed simulating moving bed (SMB has proved to be more efficient in binary separation performance (purity, recovery, productivity because of its two additional degrees of freedom, namely feed length and feed time, as compared to classical SMB process. The binary separation of dextran T6 and fructose with linear isotherm is modeled with Aspen Chromatography simulator in a four zone SMB with one column per zone for both normal-feed and Partial Feed. Increase in number of feed length and feed time in the cycle plays a very important role in the separation performance with Partial Feed. In addition, the effect of mode of operation (early or late introduction of increase in number of feed length in the cycle on product purity and recovery is also investigated. Furthermore, the binary separation system is designed with the safety margin method and the optimum operating parameters for simulation are calculated with triangle theory. Finally, a new strategy with Partial Feed is developed, showing improved separation performance relative to the basic four-zone SMB with regard to extract stream purity and recovery. The results of the proposed study can served as a useful summary of Partial Feed operation.

Gravity Drainage of Activated Sludge on Reed Beds

DEFF Research Database (Denmark)

Christensen, Morten Lykkegaard; Dominiak, Dominik Marek; Keiding, Kristian

and operation of reed beds and the efficiencies are often lower than predicted. One reason is that the sludge quality varies from plant to plant and even within plants from time to time. No good method exists for measuring the sludge quality with respect to drainage characteristics. A new experimental method...... has therefore been developed to measure relevant quality parameters: specific cake resistance, settling velocity and cake compressibility. It has been found that activated sludge form highly compressible cake even at the low compressive pressures obtained during drainage. Numerical simulation shows......Activated sludge is a by-product from waste water treatment plants, and the water content in the sludge is high (> 90%). Among several methods to remove the water, sludge drying reed beds are often used to dewater the sludge by drainage. There is, however, no well-defined criterion for design...

Feasibility study - Lowered bed temperature in Fluidised Bed boilers for waste; Foerstudie - Saenkt baeddtemperatur i FB-pannor foer avfallsfoerbraenning

Energy Technology Data Exchange (ETDEWEB)

Niklasson, Fredrik

2009-01-15

Waste incineration generally serves two purposes; 1) dispose of waste and 2) generation of heat and power. In the process of power production from waste fuels, the steam temperatures in super heaters are generally limited by the severe fouling and corrosion that occurs at elevated material temperatures, caused by high concentrations of alkali metals and chloride in the flue gas and fly ash. The overall aim of a continuation of present project is to determine if a reduced temperature of the bed zone in a fluidized bed waste incinerator reduces the amount of alkali chlorides in the flue gas. If so, a reduced bed temperature might enable increased steam temperature in super heaters, or, at unchanged steam temperature, improve the lifespan of the super heaters. The results from the project are of interest for plant owners wishing to improve performance of existing plants. The results may also be used to modify the design of future plants by boiler manufacturers. The aim of present pre-study was to determine how far the bed temperature can be reduced in a waste fired fluidized bed boiler in Boraas while maintaining a stable operation with sufficient combustion temperature in the freeboard to fulfil the directives of waste incineration. A continuation of the project will be based on the results from present study. The work is based on experiments at the test boiler. During the present study, no other measurements were performed apart from some sampling of bed material and ashes at different modes of operation. The experiments show that it is possible to alter the air and recycled flue gas in such a manner that the bed temperature is reduced from about 870 deg C to 700 deg C at 100% load and normal fuel mixture, while fulfilling the directive of 850 deg C at 2 seconds. Within normal variations of the fuel properties, however, the bed temperature increases to somewhat above 700 deg C if the fuel turns dry, while it falls below 650 deg C when the fuel turns wet. With

The research and development of pressurized ash agglomerating fluidized bed coal gasification

Energy Technology Data Exchange (ETDEWEB)

Fang Yitian; Wu Jinhu; Chen Hanshi [Chinese Academy of Sciences, Taiyuan (China). Institute of Coal Chemistry

1999-11-01

Coal gasification tests in a pressurized ash agglomeration fluidized bed coal gasifier were carried out. The effects of pressure and temperature on the gasification capacity, carbon conversion, carbon content in discharged ash and gas composition were investigated. Gasification capacity was shown to be in direct proportion to operation pressure. Tests of hot gas dedusting using a moving granular bed were also carried out. 3 refs., 6 figs., 2 tabs.

Ceramic breeder pebble bed packing stability under cyclic loads

Energy Technology Data Exchange (ETDEWEB)

Zhang, Chunbo, E-mail: chunbozhang@fusion.ucla.edu [Fusion Science and Technology Center, University of California, Los Angeles, CA 90095-1597 (United States); Ying, Alice; Abdou, Mohamed A. [Fusion Science and Technology Center, University of California, Los Angeles, CA 90095-1597 (United States); Park, Yi-Hyun [National Fusion Research Institute, Daejeon (Korea, Republic of)

2016-11-01

Highlights: • The feasibility of obtaining packing stability for pebble beds is studied. • The responses of pebble bed to cyclic loads have been presented and analyzed in details. • Pebble bed packing saturation and its applications are discussed. • A suggestion is made regarding the improvement of pebbles filling technique. - Abstract: Considering the optimization of blanket performance, it is desired that the bed morphology and packing state during reactor operation are stable and predictable. Both experimental and numerical work are performed to explore the stability of pebble beds, in particular under pulsed loading conditions. Uniaxial compaction tests have been performed for both KIT’s Li{sub 4}SiO{sub 4} and NFRI’s Li{sub 2}TiO{sub 3} pebble beds at elevated temperatures (up to 750 °C) under cyclic loads (up to 6 MPa). The obtained data shows the stress-strain loop initially moves towards the larger strain and nearly saturates after a certain number of cyclic loading cycles. The characterized FEM CAP material models for a Li{sub 4}SiO{sub 4} pebble bed with an edge-on configuration are used to simulate the thermomechanical behavior of pebble bed under ITER pulsed operations. Simulation results have shown the cyclic variation of temperature/stress/strain/gap and also the same saturation trend with experiments under cyclic loads. Therefore, it is feasible for pebble bed to maintain its packing stability during operation when disregarding pebbles’ breakage and irradiation.

Effect of a powered drive on pushing and pulling forces when transporting bariatric hospital beds.

Science.gov (United States)

Wiggermann, Neal

2017-01-01

Powered drives designed to assist with moving hospital beds are commercially available but no studies have evaluated whether they reduce the push and pull forces likely contributing to injury in caregivers. This study measured hand forces of 10 caregivers maneuvering a manual and powered bariatric bed through simulated hospital environments (hallway, elevator, and ramp). Peak push and pull forces exceeded previously established psychophysical limits for all activities with the manual bed. For the powered bed, peak forces were significantly (p pushing did not differ between beds. Powered drive may reduce the risk of injury or the number of caregivers needed for transport. Copyright © 2016 Elsevier Ltd. All rights reserved.

Fixed (slow moving) bed updraft gasification of agricultural residues

Energy Technology Data Exchange (ETDEWEB)

Vigouroux, Rolando Zanzi [Royal Institute of Technology (KTH), Stockholm (Sweden). Dept. of Chemical Engineering and Technology], E-mail: rolando@ket.kth.se; Escalona, Ronoldy Faxas [University of Oriente, Santiago de Cuba (Cuba). Fac. of Mechanical Engineering], E-mail: faxas@fim.uo.edu.cu

2009-07-01

Birch, in form of pellets has been gasified in updraft fixed-bed gasifier using air as oxidation agent. The main objectives were to study the effect of the treatment conditions on the distribution of the products and the composition of product gas. The influence of the air flow rates on the composition of the producer gas has been studied. The amount of the biomass used in the experiments was varied between 1 and 4 kg and the flow rate of the air was varied from 1.1 to 2.6 m3/h. Increased airflow rates favored higher temperatures. Excessively high airflow rates resulted in fast consumption of the biomass and it also favored combustion over gasification and thus formation of lower amounts of combustible products. High airflow rates caused also higher yields of tars, due to the shorter residence time of the tar-rich gas in the gasifier and thus unfavorable conditions for tar cracking. (author)

Nitrification of an industrial wastewater in a moving-bed biofilm reactor: effect of salt concentration.

Science.gov (United States)

Vendramel, Simone; Dezotti, Marcia; Sant'Anna, Geraldo L

2011-01-01

Nitrification of wastewaters from chemical industries can pose some challenges due to the presence of inhibitory compounds. Some wastewaters, besides their organic complexity present variable levels of salt concentration. In order to investigate the effect of salt (NaCl) content on the nitrification of a conventional biologically treated industrial wastewater, a bench scale moving-bed biofilm reactor was operated on a sequencing batch mode. The wastewater presenting a chloride content of 0.05 g l(-1) was supplemented with NaCl up to 12 g Cl(-) l(-1). The reactor operation cycle was: filling (5 min), aeration (12 or 24h), settling (5 min) and drawing (5 min). Each experimental run was conducted for 3 to 6 months to address problems related to the inherent wastewater variability and process stabilization. A PLC system assured automatic operation and control of the pertinent process variables. Data obtained from selected batch experiments were adjusted by a kinetic model, which considered ammonia, nitrite and nitrate variations. The average performance results indicated that nitrification efficiency was not influenced by chloride content in the range of 0.05 to 6 g Cl(-) l(-1) and remained around 90%. When the chloride content was 12 g Cl(-) l(-1), a significant drop in the nitrification efficiency was observed, even operating with a reaction period of 24 h. Also, a negative effect of the wastewater organic matter content on nitrification efficiency was observed, which was probably caused by growth of heterotrophs in detriment of autotrophs and nitrification inhibition by residual chemicals.

Methanol steam-reforming in a catalytic fixed bed reactor

Energy Technology Data Exchange (ETDEWEB)

Duesterwald, H G; Hoehlein, B; Kraut, H; Meusinger, J; Peters, R [Research Centre Juelich (KFA) (Germany). Inst. of Energy Process Engineering; Stimming, U [Technische Univ. Muenchen, Garching (Germany). Inst. fuer Festkoerperphysik und Techn. Phys.

1997-12-01

Designing an appropriate methanol steam reformer requires detailed knowledge about the processes within such a reactor. Thus, the axial temperature and concentration gradients and catalyst ageing were investigated. It was found that for a fresh catalyst load, the catalyst located in the reactor entrance was most active during the experiment. The activity of this part of the catalyst bed decreased after some time of operation due to ageing. With further operation, the most active zone moved through the catalyst bed. From the results concerning hydrogen production and catalyst degradation, the necessary amount of catalyst for a mobile PEMFC-system can be estimated. (orig.)

Tracking channel bed resiliency in forested mountain catchments using high temporal resolution channel bed movement

Science.gov (United States)

Martin, Sarah E.; Conklin, Martha H.

2018-01-01

This study uses continuous-recording load cell pressure sensors in four, high-elevation (1500-1800 m), Sierra Nevada headwater streams to collect high-temporal-resolution, bedload-movement data for investigating the channel bed movement patterns within these streams for water years 2012-2014. Data show an annual pattern where channel bed material in the thalweg starts to build up in early fall, peaks around peak snow melt, and scours back to baseline levels during hydrograph drawdown and base flow. This pattern is punctuated by disturbance and recovery of channel bed material associated with short-term storm events. A conceptual model, linking sediment sources at the channel margins to patterns of channel bed fill and scour in the thalweg, is proposed building on the results of Martin et al. (2014). The material in the thalweg represents a balance between sediment supply from the channel margins and sporadic, conveyor-belt-like downstream transport in the thalweg. The conceptual model highlights not only the importance of production and transport rates but also that seasonal connectedness between the margins and thalweg is a key sediment control, determining the accumulation rate of sediment stores at the margins and the redistribution of sediment from margins to thalweg that feeds the conveyor belt. Disturbance and recovery cycles are observed at multiple temporal scales; but long term, the channel beds are stable, suggesting that the beds act as short-term storage for sediment but are in equilibrium interannually. The feasibility of use for these sensors in forested mountain stream environments is tested. Despite a high failure rate (50%), load cell pressure sensors show potential for high-temporal-resolution bedload measurements, allowing for the collection of channel bed movement data to move beyond time-integrated change measurements - where many of the subtleties of bedload movement patterns may be missed - to continuous and/or real-time measurements. This

Effects of bed net use, female size, and plant abundance on the first meal choice (blood vs sugar of the malaria mosquito Anopheles gambiae

Directory of Open Access Journals (Sweden)

Stone Chris M

2012-01-01

Full Text Available Abstract Background The purpose of this study was to determine whether the sugar-or-blood meal choice of Anopheles gambiae females one day after emergence is influenced by blood-host presence and accessibility, nectariferous plant abundance, and female size. This tested the hypothesis that the initial meal of female An. gambiae is sugar, even when a blood host is available throughout the night, and, if not, whether the use of a bed net diverts mosquitoes to sugar sources. Methods Females and males Senna didymobotrya plants. Simultaneously they had access to a human blood host, either for 8 h or for only 30 min at dusk and dawn (the remainder of the night being excluded by an untreated bed net. In a third situation, the blood host was not present. All mosquitoes were collected in the morning. Their wing lengths, an indicator of pre-meal energetic state, were measured, and their meal choice was determined by the presence of midgut blood and of fructose. Results Female sugar feeding after emergence was facultative. When a blood host was accessible for 8 h per night, 92% contained blood, and only 3.7% contained sugar. Even with the use of a bed net, 78% managed to obtain a blood meal during the 30 min of accessibility at dusk or dawn, but 14% of females were now fructose-positive. In the absence of a blood host, and when either one or six plants were available, a total of 21.7% and 23.6% of females and 30.8% and 43.5% of males contained fructose, respectively. Feeding on both sugar and blood was more likely with bed net use and with greater plant abundance. Further, mosquitoes that fed on both resources were more often small and had taken a sugar meal earlier than the blood meal. The abundance of sugar hosts also affected the probability of sugar feeding by males and the amount of fructose obtained by both males and females. Conclusion Even in an abundance of potential sugar sources, female An. gambiae appear to prefer a nearby human source of blood

Waste Water Treatment-Bed of Coal Fly Ash for Dyes and Pigments Industry

Directory of Open Access Journals (Sweden)

Syed Farman Ali Shah

2015-12-01

Full Text Available The highly porous power plant waste ashes have been utilized to treat toxic effluent of a dyes manufacturing plant. An attempt has been made for the first time in Pakistan, to generate an effective and economically sound treatment facility for the toxic effluent of a dyes manufacturing plant. This is an indigenous bed which could replace expensive treatment facilities, such as reverse osmosis (RO, granulated activated carbon (GAC bed, etc. The treatment efficiency was improved by coupling coagulants with fly ash adsorbent bed. The ash was collected from coal fired boilers of power plant at Lakhra Power Generation Company, Jamshoro, Pakistan. The use of this ash resolved the disposal and environmental issues by treating wastewater of chemical, dyes and pigment industry. The treatment bed comprised of briquettes of coal fly ash coupled with commercial coagulant ferrous sulfate-lime reduced COD, color, turbidity and TSS of effluent remarkably. An adsorption capacity and chemical behavior of fly ash bed was also studied. In coagulation treatment, coagulant FeSO4-lime influenced reduction of COD, color, turbidity and TSS by 32%, 48%, 50% and 51%, respectively. The CFAB coupled with coagulant, resulted an excessive removal of color, TSS, COD, and turbidity by 88%, 92%, 67% and89%, respectively.

Waste Water Treatment-Bed of Coal Fly Ash for Dyes and Pigments Industry

International Nuclear Information System (INIS)

Shah, S.F.A.; Aftab, A.; Soomro, N.; Nawaz, M.S.; Vafai, K.

2015-01-01

The highly porous power plant waste ashes have been utilized to treat toxic effluent of a dyes manufacturing plant. An attempt has been made for the first time in Pakistan, to generate an effective and economically sound treatment facility for the toxic effluent of a dyes manufacturing plant. This is an indigenous bed which could replace expensive treatment facilities, such as reverse osmosis (RO), granulated activated carbon (GAC) bed, etc. The treatment efficiency was improved by coupling coagulants with fly ash adsorbent bed. The ash was collected from coal fired boilers of power plant at Lakhra Power Generation Company, Jamshoro, Pakistan. The use of this ash resolved the disposal and environmental issues by treating wastewater of chemical, dyes and pigment industry. The treatment bed comprised of briquettes of coal fly ash coupled with commercial coagulant ferrous sulfate-lime reduced COD, color, turbidity and TSS of effluent remarkably. An adsorption capacity and chemical behavior of fly ash bed was also studied. In coagulation treatment, coagulant FeSO/sun 4/-lime influenced reduction of COD, color, turbidity and TSS by 32 percentage, 48 percentage, 50 percentage and 51 percentage, respectively. The CFAB coupled with coagulant, resulted an excessive removal of color, TSS, COD, and turbidity by 88 percentage, 92 percentage, 67 percentage and 89 percentage, respectively. (author)

Operating experience and data on revolving type fluidized bed incineration plants

International Nuclear Information System (INIS)

Nakayama, J.

1990-01-01

In refuse incinerators operating by revolving fluidization (Revolving Type Fluidized Bed Incinerator) a broad range of wastes, from low caloric refuse of high moisture content to high caloric value material including a wide variety of plastics, can be incinerated at high efficiency because the unit is outstanding in terms of distribution of waste in the incinerator bed and uniformity of heat. In addition, its vigorous revolving fluidization action is very effective in pulverizing refuse, so even relatively strict emission standards can be met without fine pre-shredding. Residues are discharged in a clean, dry form free of putrescible material. Data on practical operation of the revolving fluidized bed incinerator are presented in this paper

Ion leakage from mixed beds in condensate polishing plants

International Nuclear Information System (INIS)

Venderbosch, H.W.; Overman, L.J.; Snel, A.

1977-01-01

In view to the interest for theoretical and practical factors, which influence the ion slip of mixed bed filters, these facts were studied in detail. It proved to be necessary that the slip shall be subdivided into kinetic - and elution slip. The kinetic slip is depending e.g. on the electrolyte concentration of the influenct condensate, as well as on the period of contact, however it does not depend on the regeneration condition; the elution slip however depends clearly on the regeneration condition. Incomplete regeneration of the exchangers, a too low excess of regenerant, incomplete separation of cation - and anion exchanger, and the contact of an exchanger layer with the wrong regenerant in the separation zone, during the internal regeneration are raising the slip. With tests on mixed bed filters, which have been well regenerated, (less than 0.1% Na in the cation exchanger) and by using filters with normal regenerated exchangers, (approx. 10% Na in the cation exchanger) the quality of the effluent was compared with values, which were expected from calculations. In order to decrease the elution leakage, the contamination of the exchangers, especially at NH 4 OH - mixed bed filters, must be limited to a very low percentage. Several possibilities to obtain this, will be discussed in the lecture. Special attention will be paid to the internal regeneration procedure. KEMA has developed a method, the so-called partial regeneration method, in order to operate internal regenerated mixed bed filters, which have been designed for the HOH cycle, also in the ammonia form, without the occurence of an undue slip of sodium or chloride. Not only extended running periods and lower operating- and regeneration costs are of advantage, but also the reducing of salt- and ammonia containing sewage were achieved. (orig.) [de

Effect of various drying bed on thermodynamic characteristics

Directory of Open Access Journals (Sweden)

Ali Motevali

2017-09-01

Full Text Available In this study thermodynamic parameter and energy consumption in drying of two plant dill and mint in three bed drying including fix, semi fix and fluid with using a hot air drying was investigated. Experimental was conducted in three bed drying including fix, semi fix and fluid and four levels temperature (30, 40, 50 and 60 °C. Maximum energy consumption in dill drying at 40 °C and fluid bed to be 16.41 MJ and minimum energy consumption at 30 °C and fix bed to be 2.77 MJ. Also minimum energy consumption in mint drying at 60 °C and fix bed to be 3.64 MJ and maximum energy consumption at 40 °C and fluid bed to be 28.65 MJ. The highest energy, drying and thermal efficiency for both mint and dill was achieved at 60 °C on the fixed bed, whereas the lowest efficiency was at 40 °C and on the fluidized bed. Also the highest power and specific heat consumption for both mint and dill was achieved at 40 °C on the fluid bed, whereas the lowest efficiency was at 30 °C and on the fluidized bed.

Dissolved oxygen control in a coupled fluidized bed system

International Nuclear Information System (INIS)

Jones, R.M.; Melcer, H.

1988-01-01

The biological fluidized bed process is a modification of more conventional fixed film processes, such as the trickling filter, in which wastewater is passed upward through a bed of granular support medium, typically sand, at a sufficient velocity to expand or fluidize the medium. The granular medium provides a large surface area for the establishment of a biological film. The fluidized bed process was selected to investigate the treatment of coking plant wastewaters in view of the significant advantages offered in terms of reduced reactor volumes that result from the high biomass concentration maintained on the support medium. The technical feasibility of treating coal distillation condensates was evaluated during a 3-year study at Environment Canada's Wastewater Technology Centre (WTC). The feed to the pilot scale test system consisted of effluent from fixed and free leg ammonia stills at the by-product coke plant of Dofasco Inc. in Hamilton, Ontario. The pilot plant consisted of two fluidized bed reactors in series, coupled to provide carbon oxidation, nitrification and denitrification in the predenitrification operating mode. The anoxic denitrification reactor was 115 mm in diameter and the oxygenic nitrification reactor, 290 mm in diameter. The bed heights and reactor volumes were adjustable by relocation of the position of the sand/biomass wasting valve. The experimental objective of this research was to determine those operating conditions required to maintain stable nitrification and complete denitrification under both steady state and dynamic operating conditions. Details regarding operating, sampling and analytic procedures have been presented elsewhere. A specific operating problem existed relating to the control of the dissolved oxygen concentration in the oxygenic fluidized bed reactor, the solution of which forms the basis of the paper

Waste Water Treatment-Bed of Coal Fly Ash for Dyes and Pigments Industry

OpenAIRE

Syed Farman Ali Shah; Aziza Aftab; Noorullah Soomro; Mir Shah Nawaz; Kambiz Vafai

2015-01-01

The highly porous power plant waste ashes have been utilized to treat toxic effluent of a dyes manufacturing plant. An attempt has been made for the first time in Pakistan, to generate an effective and economically sound treatment facility for the toxic effluent of a dyes manufacturing plant. This is an indigenous bed which could replace expensive treatment facilities, such as reverse osmosis (RO), granulated activated carbon (GAC) bed, etc. The treatment efficiency was improved by coupling c...

Does bedding promote pine survival and growth on ditched wet sands?

Science.gov (United States)

Ralph A. Klawitter

1970-01-01

Results from a study of prepared beds for planting slash pine on a wet sandy flat in Florida were inconclusive. Early growth was improved, but survival was not; and differences between a bedded site and an unbedded site were slight.

Effects of Fluidization Velocity and Bed Particle Size on Bed Defluidization during Biomass Combustion in FB boilers; Effekten av fluidiseringshastighet och kornstorlek paa agglomereringsrisk vid biobraensleeldning i FB-pannor

Energy Technology Data Exchange (ETDEWEB)

Eriksson, Morgan; Oehman, Marcus [Umeaa Univ. (Sweden). Applied Physics and Electronics; Wikman, Karin; Berg, Magnus [AaF-Energi och Miljoe AB, Stockholm (Sweden)

2004-11-01

Studies on the effect of bed particle size and fluidization velocity on the agglomeration/defluidization risk during biomass combustion in BFB/CFB plants have not previously been published. Therefore, the objective of this project has been to determine the influence of these two parameters on the risk for agglomeration in typical biofuel fired fluidized beds. The study has also resulted in information on how variations in the coating characteristics of the bed particles are depending on the fuel ash content and the particle size of the bed material. Furthermore, the conditions at large scale commercial plants have been surveyed with respect to the choice of bed material, fluidization velocity, bed sand consumption etc. Bed materials have been sampled from seven full-scale boilers, four CFB and three BFB. The samples have been sieved to achieve sieve curves, analyzed with respect to the coating characteristics, and studied by experiments in a bench-scale fluidized bed. It could be concluded from the analyses that there are no significant differences in the coating thickness or the coating composition between fine and coarse particles in the bed samples. The bench-scale agglomeration experiments showed that increased fluidization velocity results in bed agglomeration at a higher temperature. This effect was stronger at relatively low fluidization velocities. The fluidization velocity has probably no significant effect on the risk for agglomeration at normal gas velocities in a commercial CFB boiler. Though, it could have an influence on the agglomeration in for example the recycling part of a CFB, where the gas velocity is relatively low. Also in BFB-boilers the fluidization velocity is often low enough to have a significant effect on the risk for agglomeration. By the experiments in this project it has not been possible to determine if the bed particle size has an influence on the agglomeration. Further studies with modified methods are required to find out if the

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

Particle flow of ceramic breeder pebble beds in bi-axial compression experiments

International Nuclear Information System (INIS)

Hermsmeyer, S.; Reimann, J.

2002-01-01

Pebble beds of ceramic material are investigated within the framework of developing solid breeder blankets for future fusion power plants. A thermo-mechanical characterisation of such pebble beds is mandatory for understanding the behaviour of pebble beds, and thus the overall blanket, under fusion environment conditions. The mechanical behaviour of pebble beds is typically explored with uni-axial, bi-axial and tri-axial compression experiments. The latter two types of experiment are particularly revealing since they contain explicitly, beyond a compression behaviour of the bed, information on the conditions for pebble flow, i.e. macroscopic relocation, in the pebble bed. (orig.)

Crud removal with deep bed type condensate demineralizer in Tokai-2 BWR

International Nuclear Information System (INIS)

Abe, Ayumi; Takiguchi, Hideki; Numata, Kunio; Saito, Toshihiko

1996-01-01

The major objective and functions for the installation of the deep bed type condensate polishers in BWR power plants is to remove both ionic impurities caused by sea water leakage and suspended impurities called crud mainly consisting of metal oxides which are produced from metal corrosion. In considering the reduction of occupational radiation exposure level, it is extremely important to remove the crud effectively. In recent Japanese BWR power plants, condensate pre-filters with powdered ion exchange resins or with hollow fiber membrane have been installed to remove the crud at the upper stream of the deep bed polishers. In such plants, the crud removal is conventionally the secondary objective for the deep bed polishers. The Japan Atomic Power Company has introduced the small particle ion exchange resin and a soak regeneration method since April 1985, and then applied the low cross-linked resin since July 1995 at Tokai-2 Power Station, to improve the crud removal performance by using only deep bed type condensate demineralizer, and as a result condensate demineralizer outlet iron level has been kept below 1 ppb since 1991

Fiscal 1994 achievement report. Development of entrained bed coal gasification power plant (Part 5 - Survey of demonstration plant); 1994 nendo seika hokokusho. Funryusho sekitan gaska hatsuden plant kaihatsu - Sono 5. Jissho plant ni kansuru chosa kenkyu hen

Energy Technology Data Exchange (ETDEWEB)

NONE

1995-07-01

A survey was conducted of a demonstration plant for developing the technology of integrated coal gasification combined cycle power generation. In fiscal 1994, based on the studies of pilot plant operation conducted up to the preceding fiscal year and on the studies of a demonstration plant (conceptual design of a demonstration plant), systems were examined for still higher performance and economical efficiency. For optimizing the heat source for pulverized coal drying air, an extracted air heat utilizing system was adopted, excellent in performance (approximately 0.5% improvement in absolute value) and in economical efficiency. For reducing the consumption of inert gas for the fluidized bed desulfurization facility, an approximately 30% reduction was found to be possible dependent on gas regeneration conditions in the regeneration tower. For performance improvement with the combined cycle equipment placed under a partial load, the generating-end efficiency was improved approximately 0.2% when only SGC (syngas cooler) was loaded 80% or less and kept at a constant pressure. Studies were also made about how to maintain a constant output with the equipment exposed to air temperature changes. (NEDO)

Trends in infant bedding use: National Infant Sleep Position study, 1993-2010.

Science.gov (United States)

Shapiro-Mendoza, Carrie K; Colson, Eve R; Willinger, Marian; Rybin, Denis V; Camperlengo, Lena; Corwin, Michael J

2015-01-01

Use of potentially hazardous bedding, as defined by the American Academy of Pediatrics (eg, pillows, quilts, comforters, loose bedding), is a modifiable risk factor for sudden infant death syndrome and unintentional sleep-related suffocation. The proportion of US infants sleeping with these types of bedding is unknown. To investigate the US prevalence of and trends in bedding use, we analyzed 1993-2010 data from the National Infant Sleep Position study. Infants reported as being usually placed to sleep with blankets, quilts, pillows, and other similar materials under or covering them in the last 2 weeks were classified as bedding users. Logistic regression was used to describe characteristics associated with bedding use. From 1993 to 2010, bedding use declined but remained a widespread practice (moving average of 85.9% in 1993-1995 to 54.7% in 2008-2010). Prevalence was highest for infants of teen-aged mothers (83.5%) and lowest for infants born at term (55.6%). Bedding use was also frequently reported among infants sleeping in adult beds, on their sides, and on a shared surface. The rate of decline in bedding use was markedly less from 2001-2010 compared with 1993-2000. For 2007 to 2010, the strongest predictors (adjusted odds ratio: ≥1.5) of bedding use were young maternal age, non-white race and ethnicity, and not being college educated. Bedding use for infant sleep remains common despite recommendations against this practice. Understanding trends in bedding use is important for tailoring safe sleep interventions. Copyright © 2015 by the American Academy of Pediatrics.

Development of Chinese HTR-PM pebble bed equivalent conductivity test facility

Energy Technology Data Exchange (ETDEWEB)

Ren, Cheng; Yang, Xingtuan; Jiang, Shengyao [Tsinghua Univ., Beijing (China). Inst. of Nuclear and New Energy Technology

2016-01-15

The first two 250-MWt high-temperature reactor pebble bed modules (HTR-PM) have been installing at the Shidaowan plant in Shandong Province, China. The values of the effective thermal conductivity of the pebble bed core are essential parameters for the design. For their determination, Tsinghua University in China has proposed a full-scale heat transfer experiment to conduct comprehensive thermal transfer tests in packed pebble bed and to determine the effective thermal conductivity.

Fluidized-bed incineration plant equipped with waste heat boilers. Developed for mid-size municipalities

Energy Technology Data Exchange (ETDEWEB)

Handa, Hitoshi

1988-01-20

A fluidized bed incineration plant with a waste heat boiler was installed to dispose wastes in Sakura City on March, 1987 and has waste disposing capacity of 120tons/d. Sands are fluidized in the furnace at 700-800/sup 0/C and wastes are burned completely for a short time. The waste heat boiler is used to utilize waste heat to send steam to aquiculturing farms and hot water to the community plaza and further supplies steam to two 90kW back pressure turbines for driving forced draft fan used for the incineration plant. Harmful gases in waste gas are removed by the harmful gas eliminator to lower HCl to 120ppm or less and K value of SOx to 9.0 or less and then cleaned gas is exhausted through the electostatic precipitator and the chimney. Dust and fly ash are transferred to a reservior through a superior seal tight air transportation system, pelletized and disposed for land fill. Bulk waste disposing capacity is 50 tons/d and harmful wastes, magnetic materials, unburnable and burnable wastes are classified and separated. Separated iron purity is 95% or more. (4 figs, 2 photos)

Performance evaluation and optimization of fluidized bed boiler in ethanol plant using irreversibility analysis

Directory of Open Access Journals (Sweden)

Nugroho Agung Pambudi

2017-09-01

Full Text Available This research aims to evaluate the performance of a fluidized bed boiler in an ethanol production plant through exergy and irreversibility analysis. The study also includes the optimization of the pre-heater and the deaerator in order to improve the system efficiency. Operational data from the ethanol production plant was collected between 2015 and early 2016. The total exergy derived from the fuel was determined to be 7783 kJ/s, while the exergy efficiency of the system was found to be 26.19%, with 2214 kJ/s used in steam production, while 71.55% was lost to component irreversibility and waste heat from the pre-heater. The exergy efficiencies of individual components of the system such as the boiler, deaerator, and pre-heater were found to be 25.82%, 40.13%, and 2.617%, respectively, with the pre-heater having the lowest efficiency. Thus, the pre-heater has the highest potential to significantly improve the efficiency of the boiler system. The optimization of the pre-heater shows that a rise in temperature in the outlet of the pre-heater positively affects the exergy efficiency of the deaerator.

Experience gained in pilot-scale and bench-scale fluidised beds processing

CSIR Research Space (South Africa)

Hadley, TD

2006-02-01

Full Text Available for clean coal technology thrust COMMISSIONED PLANTS Slagment Hot Gas Generator Client : Slagment Bed area : 25 m2 Plant purpose : A 10 MW plant for the combustion of duff coal at greater than 98% burnout to provide hot gases for the drying...

Bubbling behavior of a fluidized bed of fine particles caused by vibration-induced air inflow.

Science.gov (United States)

Matsusaka, Shuji; Kobayakawa, Murino; Mizutani, Megumi; Imran, Mohd; Yasuda, Masatoshi

2013-01-01

We demonstrate that a vibration-induced air inflow can cause vigorous bubbling in a bed of fine particles and report the mechanism by which this phenomenon occurs. When convective flow occurs in a powder bed as a result of vibrations, the upper powder layer with a high void ratio moves downward and is compressed. This process forces the air in the powder layer out, which leads to the formation of bubbles that rise and eventually burst at the top surface of the powder bed. A negative pressure is created below the rising bubbles. A narrow opening at the bottom allows the outside air to flow into the powder bed, which produces a vigorously bubbling fluidized bed that does not require the use of an external air supply system.

Emergence of traveling wave endothermic reaction in a catalytic fixed bed under microwave heating

International Nuclear Information System (INIS)

Gerasev, Alexander P.

2017-01-01

This paper presents a new phenomenon in a packed bed catalytic reactor under microwave heating - traveling wave (moving reaction zones) endothermic chemical reaction. A two-phase model is developed to simulate the nonlinear dynamic behavior of the packed bed catalytic reactor with an irreversible first-order chemical reaction. The absorbed microwave power was obtained from Lambert's law. The structure of traveling wave endothermic chemical reaction was explored. The effects of the gas velocity and microwave power on performance of the packed bed catalytic reactor were presented. Finally, the effects of the change in the location of the microwave source at the packed bed reactor was demonstrated. - Highlights: • A new phenomenon - traveling waves of endothermic reaction - is predicted. • The physical and mathematical model of a packed bed catalytic reactor under microwave heating is presented. • The structure of the traveling waves is explored. • The configuration of heating the packed bed reactor via microwave plays a key role.

Management of turbidity current venting in reservoirs under different bed slopes.

Science.gov (United States)

Chamoun, Sabine; De Cesare, Giovanni; Schleiss, Anton J

2017-12-15

The lifetime and efficiency of dams is endangered by the process of sedimentation. To ensure the sustainable use of reservoirs, many sediment management techniques exist, among which venting of turbidity currents. Nevertheless, a number of practical questions remain unanswered due to a lack of systematic investigations. The present research introduces venting and evaluates its performance using an experimental model. In the latter, turbidity currents travel on a smooth bed towards the dam and venting is applied through a rectangular bottom outlet. The combined effect of outflow discharge and bed slopes on the sediment release efficiency of venting is studied based on different criteria. Several outflow discharges are tested using three different bed slopes (i.e., 0%, 2.4% and 5.0%). Steeper slopes yield higher venting efficiency. Additionally, the optimal outflow discharge leading to the largest venting efficiency with the lowest water loss increases when moving from the horizontal bed to the inclined positions. Copyright © 2017 Elsevier Ltd. All rights reserved.

Petrographic and X-ray diffraction analyses of selected samples from Marker Bed 139 at the Waste Isolation Pilot Plant

International Nuclear Information System (INIS)

Fredrich, J.T.; Zeuch, D.H.

1996-04-01

The Waste Isolation Pilot Plant (WIPP) is located 660 m underground in the Salado Formation which consists of thick, horizontally bedded pure and impure salt and thin, laterally continuous clay and anhydrite interbeds. The Salado Two-Phase Flow Laboratory Program was established to provide site-specific-two-phase flow and other related rock properties to support performance assessment modeling of the WIPP repository. Owing to their potentially significant role in the hydrologic response of the repository, the program initially focused on the anhydrite interbeds, and in particular, on Marker Bed 139 (MB 139), which lies approximately 1 m below the planned waste storage rooms. This report synthesizes petrographic and X-ray powder diffraction studies performed to support the Salado Two-Phase Flow Laboratory Program. Experimental scoping activities in this area were performed in FY 1993 by three independent laboratories in order to: (1) quantify the mineral composition to support laboratory studies of hydrologic properties and facilitate correlation of transport properties with composition; (2) describe textures, including grain size; and (3) describe observed porosity. Samples from various depths were prepared from six 6-inch diameter cores which were obtained by drilling into the marker bed from the floor of two separate rooms. The petrographic analyses are augmented here with additional study of the original thin sections, and the pore structure observations are also examined in relation to an independent observational study of microcracks in Marker Bed 139 core samples performed in FY 1994 by the Geomechanics Department at Sandia National Laboratories

Petrographic and X-ray diffraction analyses of selected samples from Marker Bed 139 at the Waste Isolation Pilot Plant

Energy Technology Data Exchange (ETDEWEB)

Fredrich, J.T.; Zeuch, D.H. [Sandia National Labs., Albuquerque, NM (United States). Geomechanics Dept.

1996-04-01

The Waste Isolation Pilot Plant (WIPP) is located 660 m underground in the Salado Formation which consists of thick, horizontally bedded pure and impure salt and thin, laterally continuous clay and anhydrite interbeds. The Salado Two-Phase Flow Laboratory Program was established to provide site-specific-two-phase flow and other related rock properties to support performance assessment modeling of the WIPP repository. Owing to their potentially significant role in the hydrologic response of the repository, the program initially focused on the anhydrite interbeds, and in particular, on Marker Bed 139 (MB 139), which lies approximately 1 m below the planned waste storage rooms. This report synthesizes petrographic and X-ray powder diffraction studies performed to support the Salado Two-Phase Flow Laboratory Program. Experimental scoping activities in this area were performed in FY 1993 by three independent laboratories in order to: (1) quantify the mineral composition to support laboratory studies of hydrologic properties and facilitate correlation of transport properties with composition; (2) describe textures, including grain size; and (3) describe observed porosity. Samples from various depths were prepared from six 6-inch diameter cores which were obtained by drilling into the marker bed from the floor of two separate rooms. The petrographic analyses are augmented here with additional study of the original thin sections, and the pore structure observations are also examined in relation to an independent observational study of microcracks in Marker Bed 139 core samples performed in FY 1994 by the Geomechanics Department at Sandia National Laboratories.

Hydrogen production by enhanced-sorption chemical looping steam reforming of glycerol in moving-bed reactors

International Nuclear Information System (INIS)

Dou, Binlin; Song, Yongchen; Wang, Chao; Chen, Haisheng; Yang, Mingjun; Xu, Yujie

2014-01-01

Highlights: • New approach on continuous high-purity H 2 produced auto-thermally with long time. • Low-cost NiO/NiAl 2 O 4 exhibited high redox performance to H 2 from glycerol. • Oxidation, steam reforming, WSG and CO 2 capture were combined into a reactor. • H 2 purity of above 90% was produced without heating at 1.5–3.0 S/C and 500–600 °C. • Sorbent regeneration and catalyst oxidization achieved simultaneously in a reactor. - Abstract: The continuous high-purity hydrogen production by the enhanced-sorption chemical looping steam reforming of glycerol based on redox reactions integrated with in situ CO 2 removal has been experimentally studied. The process was carried out by a flow of catalyst and sorbent mixture using two moving-bed reactors. Various unit operations including oxidation, steam reforming, water gas shrift reaction and CO 2 removal were combined into a single reactor for hydrogen production in an overall economic and efficient process. The low-cost NiO/NiAl 2 O 4 catalyst efficiently converted glycerol and steam to H 2 by redox reactions and the CO 2 produced in the process was simultaneously removed by CaO sorbent. The best results with an enriched hydrogen product of above 90% in auto-thermal operation for reforming reactor were achieved at initial temperatures of 500–600 °C and ratios of steam to carbon (S/C) of 1.5–3.0. The results indicated also that not all of NiO in the catalyst can be reduced to Ni by the reaction with glycerol, and the reduced Ni can be oxidized to NiO by air at 900 °C. The catalyst oxidization and sorbent regeneration were achieved under the same conditions in air reactor

Restoring lakes by using artificial plant beds: habitat selection of zooplankton in a clear and a turbid shallow lake

DEFF Research Database (Denmark)

Schou, Majbritt Overgård; Risholt, Casper; Lauridsen, Torben L.

2009-01-01

1. Return of large-bodied zooplankton populations is of key importance for creating a shift from a turbid to a clear-water state in shallow lakes after a nutrient loading reduction. In temperate lakes, recovery is promoted by submerged macrophytes which function as a daytime refuge for large...... zooplankton. However, recovery of macrophytes is often delayed and use of artificial plant beds (APB) has been suggested as a tool to enhance zooplankton refuges, thereby reinforcing the shift to a clear-water state and, eventually, colonisation of natural plants. 2. To further evaluate the potential of APB...... in lake restoration, we followed the day–night habitat choices of zooplankton throughout summer in a clear and a turbid lake. Observations were made in the pelagic and littoral zones and in APB in the littoral representing three different plant densities (coverage 0%, 40% and 80%). 3. In the clear lake...

Optimization of reactive simulated moving bed systems with modulation of feed concentration for production of glycol ether ester.

Science.gov (United States)

Agrawal, Gaurav; Oh, Jungmin; Sreedhar, Balamurali; Tie, Shan; Donaldson, Megan E; Frank, Timothy C; Schultz, Alfred K; Bommarius, Andreas S; Kawajiri, Yoshiaki

2014-09-19

In this article, we extend the simulated moving bed reactor (SMBR) mode of operation to the production of propylene glycol methyl ether acetate (DOWANOL™ PMA glycol ether) through the esterification of 1-methoxy-2-propanol (DOWANOL™ PM glycol ether) and acetic acid using AMBERLYST™ 15 as a catalyst and adsorbent. In addition, for the first time, we integrate the concept of modulation of the feed concentration (ModiCon) to SMBR operation. The performance of the conventional (constant feed) and ModiCon operation modes of SMBR are analyzed and compared. The SMBR processes are designed using a model based on a multi-objective optimization approach, where a transport dispersive model with a linear driving force for the adsorption rate has been used for modeling the SMBR system. The adsorption equilibrium and kinetics parameters are estimated from the batch and single column injection experiments by the inverse method. The multiple objectives are to maximize the production rate of DOWANOL™ PMA glycol ether, maximize the conversion of the esterification reaction and minimize the consumption of DOWANOL™ PM glycol ether which also acts as the desorbent in the chromatographic separation. It is shown that ModiCon achieves a higher productivity by 12-36% over the conventional operation with higher product purity and recovery. Copyright © 2014 Elsevier B.V. All rights reserved.

Treatment of pesticide wastewater by moving-bed biofilm reactor combined with Fenton-coagulation pretreatment

Energy Technology Data Exchange (ETDEWEB)

Chen Sheng [School of Municipal and Environmental Engineering, Harbin Institute of Technology, Harbin 150090 (China)]. E-mail: hitchensheng@126.com; Sun Dezhi [School of Municipal and Environmental Engineering, Harbin Institute of Technology, Harbin 150090 (China); Chung, J.-S. [School of Municipal and Environmental Engineering, Harbin Institute of Technology, Harbin 150090 (China); Department of Chemical Engineering, Pohang University of Science and Technology, Pohang 790-784 (Korea, Republic of)

2007-06-01

In order to treat pesticide wastewater having high chemical oxygen demand (COD) value and poor biodegradability, Fenton-coagulation process was first used to reduce COD and improve biodegradability and then was followed by biological treatment. Optimal experimental conditions for the Fenton process were determined to be Fe{sup 2+} concentration of 40 mmol/L and H{sub 2}O{sub 2} dose of 97 mmol/L at initial pH 3. The interaction mechanism of organophosphorous pesticide and hydroxyl radicals was suggested to be the breakage of the P=S double bond and formation of sulfate ions and various organic intermediates, followed by formation of phosphate and consequent oxidation of intermediates. For the subsequent biological treatment, 3.2 g/L Ca(OH){sub 2} was added to adjust the pH and further coagulate the pollutants. The COD value could be evidently decreased from 33,700 to 9300 mg/L and the ratio of biological oxygen demand (BOD{sub 5}) to COD of the wastewater was enhanced to over 0.47 by Fenton oxidation and coagulation. The pre-treated wastewater was then subjected to biological oxidation by using moving-bed biofilm reactor (MBBR) inside which tube chip type bio-carriers were fluidized upon air bubbling. Higher than 85% of COD removal efficiency could be achieved when the bio-carrier volume fraction was kept more than 20% by feeding the pretreated wastewater containing 3000 mg/L of inlet COD at one day of hydraulic retention time (HRT), but a noticeable decrease in the COD removal efficiency when the carrier volume was decreased down to 10%, only 72% was observed. With the improvement of biodegradability by using Fenton pretreatment, also due to the high concentration of biomass and high biofilm activity using the fluidizing bio-carriers, high removal efficiency and stable operation could be achieved in the biological process even at a high COD loading of 37.5 gCOD/(m{sup 2} carrier day)

Three column intermittent simulated moving bed chromatography: 3. Cascade operation for center-cut separations.

Science.gov (United States)

Jermann, Simon; Meijssen, Mattheus; Mazzotti, Marco

2015-01-23

A general design methodology for chromatographic three fraction separation by application of the three column intermittent simulated moving bed (3C-ISMB) cascade is proposed and experimentally validated by studying the purification of an intermediately retained stereoisomer of nadolol, from an equimolar mixture of its four stereoisomers. The theoretical part shows that the 3C-ISMB cascade can be easily designed by applying Triangle Theory. Moreover, a re-scaling approach for the second stage is proposed so as to account for the fact that the feed flow rates to stage 2 are generally higher as compared to stage 1 due to dilution in the latter. Scaling the columns of the second stage accordingly enables to run both stages under optimal conditions with respect to switching time and step ratio, which is an important advantage as compared to integrated ternary processes. The experimental part starts with studying the linear adsorption behavior of nadolol in heptane/ethanol/DEA on Chiralpak AD for varying ratios of heptane and ethanol. Based on that, a solvent composition of Hept/EtOH/DEA 30/70/0.3 (v/v/v) is selected and the competitive multi-component Langmuir isotherm of the quaternary mixture is determined by frontal analysis. The resulting isotherm parameters are used to design several first stage experiments aiming at removal of the most retained component. The resulting ternary intermediate product is reprocessed in several second stage experiments studying various configurations. Finally, the dilution of the intermediate product with Hept/DEA yielding a solvent composition of Hept/EtOH/DEA 60/40/0.3 (v/v/v) is examined showing that the resulting increase in retention is beneficial for final product purities. Moreover, the reduction in viscosity compensates for the dilution as it enables higher flow rates. Dilution of the intermediate product is hence the best option, yielding highest overall cascade productivity (2.10gl(-1)h(-1)) and highest product purity (97

Treatment of pesticide wastewater by moving-bed biofilm reactor combined with Fenton-coagulation pretreatment

International Nuclear Information System (INIS)

Chen Sheng; Sun Dezhi; Chung, J.-S.

2007-01-01

In order to treat pesticide wastewater having high chemical oxygen demand (COD) value and poor biodegradability, Fenton-coagulation process was first used to reduce COD and improve biodegradability and then was followed by biological treatment. Optimal experimental conditions for the Fenton process were determined to be Fe 2+ concentration of 40 mmol/L and H 2 O 2 dose of 97 mmol/L at initial pH 3. The interaction mechanism of organophosphorous pesticide and hydroxyl radicals was suggested to be the breakage of the P=S double bond and formation of sulfate ions and various organic intermediates, followed by formation of phosphate and consequent oxidation of intermediates. For the subsequent biological treatment, 3.2 g/L Ca(OH) 2 was added to adjust the pH and further coagulate the pollutants. The COD value could be evidently decreased from 33,700 to 9300 mg/L and the ratio of biological oxygen demand (BOD 5 ) to COD of the wastewater was enhanced to over 0.47 by Fenton oxidation and coagulation. The pre-treated wastewater was then subjected to biological oxidation by using moving-bed biofilm reactor (MBBR) inside which tube chip type bio-carriers were fluidized upon air bubbling. Higher than 85% of COD removal efficiency could be achieved when the bio-carrier volume fraction was kept more than 20% by feeding the pretreated wastewater containing 3000 mg/L of inlet COD at one day of hydraulic retention time (HRT), but a noticeable decrease in the COD removal efficiency when the carrier volume was decreased down to 10%, only 72% was observed. With the improvement of biodegradability by using Fenton pretreatment, also due to the high concentration of biomass and high biofilm activity using the fluidizing bio-carriers, high removal efficiency and stable operation could be achieved in the biological process even at a high COD loading of 37.5 gCOD/(m 2 carrier day)

Moving bed filter for absorbing hydrogen sulphide from biogas. Filtro de lecho movil para absorber el sulphidrico del biogas

Energy Technology Data Exchange (ETDEWEB)

Bou, J.

1994-01-01

The main aim of this demonstration project is the absorption of hydrogen sulphide from the biogas-produced in a sewage plant-through a practical system which does not require constant attention, nor significant labour for the loading and unloading of the iron oxides; and the use of the biogas, when it has been purified, in thermal and cogeneration engine applications. The demonstration installation comprises a filter with a movable bed, of pyramid/trunk shape, with a square base, having a capacity of 1,000 litres, plus the two items needed for working with it: a lower and an upper hopper, for the loading and unloading of iron-oxide agglomerates. The purified biogas is used in a cogeneration unit comprising four TOTEM-FIAT sets generating 12.5 kWh of electrical power and 36.78 thermal kW each. Completing the project is a system which receives and stores the data from the range of variables monitored. The results obtained-the H[sub 2] content at the outlet from the lower filter at 300 ppm, sulphur absorption of 30% by wight in the iron oxide agglomerates, agglomerates replacement cost of 0.77 pesetas; m''3 , and 2.47-year-pay-back- confirm the viability of the process, and resure the application of this system in other sewage treatment plants. (Author)

Idealized debris flow in flume with bed driven by a conveyor belt

Science.gov (United States)

Ling, Chi-Hai; Chen, Cheng-lung

1989-01-01

The generalized viscoplastic fluid (GVF) model is used to derive the theoretical expressions of two-dimensional velocities and surface profile for debris flow established in a flume with bed driven by a conveyor belt. The rheological parameters of the GVF model are evaluated through the comparison of theoretical results with measured data. A slip velocity of the established (steady) nonuniform flow on the moving bed (i.e., the conveyor belt) is observed, and a relation between the slip velocity and the velocity gradient at the bed is derived. Two belts, one rough and the other smooth, were tested. The flow profile in the flume is found to be linear and dependent on the roughness of the belt, but not much on its speed.

Extraction of uranium from seawater: chemical process and plant design feasibility study

International Nuclear Information System (INIS)

Campbell, M.H.; Frame, J.M.; Dudey, N.D.; Kiel, G.R.; Mesec, V.; Woodfield, F.W.; Binney, S.E.; Jante, M.R.; Anderson, R.C.; Clark, G.T.

1979-02-01

A major assessment was made of the uranium resources in seawater. Several concepts for moving seawater to recover the uranium were investigated, including pumping the seawater and using natural ocean currents or tides directly. The optimal site chosen was on the southeastern Puerto Rico coast, with the south U.S. Atlantic coast as an alternate. The various processes for extracting uranium from seawater were reviewed, with the adsorption process being the most promising at the present time. Of the possible adsorbents, hydrous titanium oxide was found to have the best properties. A uranium extraction plant was conceptually designed. Of the possible methods for contacting the seawater with the adsorbent, a continuous fluidized bed concept was chosen as most practical for a pumped system. A plant recovering 500 tonnes of U 3 O 8 per year requires 5900 cubic meters per second of seawater to be pumped through the adsorbent beds for a 70% overall recovery efficiency. Total cost of the plant was estimated to be about $6.2 billion. A computer model for the process was used for parametric sensitivity studies and economic projections. Several design case variations were developed. Other topics addressed were the impact of co-product recovery, environmental considerations, etc

Extraction of uranium from seawater: chemical process and plant design feasibility study

Energy Technology Data Exchange (ETDEWEB)

Campbell, M.H.; Frame, J.M.; Dudey, N.D.; Kiel, G.R.; Mesec, V.; Woodfield, F.W.; Binney, S.E.; Jante, M.R.; Anderson, R.C.; Clark, G.T.

1979-02-01

A major assessment was made of the uranium resources in seawater. Several concepts for moving seawater to recover the uranium were investigated, including pumping the seawater and using natural ocean currents or tides directly. The optimal site chosen was on the southeastern Puerto Rico coast, with the south U.S. Atlantic coast as an alternate. The various processes for extracting uranium from seawater were reviewed, with the adsorption process being the most promising at the present time. Of the possible adsorbents, hydrous titanium oxide was found to have the best properties. A uranium extraction plant was conceptually designed. Of the possible methods for contacting the seawater with the adsorbent, a continuous fluidized bed concept was chosen as most practical for a pumped system. A plant recovering 500 tonnes of U/sub 3/O/sub 8/ per year requires 5900 cubic meters per second of seawater to be pumped through the adsorbent beds for a 70% overall recovery efficiency. Total cost of the plant was estimated to be about $6.2 billion. A computer model for the process was used for parametric sensitivity studies and economic projections. Several design case variations were developed. Other topics addressed were the impact of co-product recovery, environmental considerations, etc.

Role of hydraulic retention time and granular medium in microbial removal in tertiary treatment reed beds.

Science.gov (United States)

García, Joan; Vivar, Joan; Aromir, Maria; Mujeriego, Rafael

2003-06-01

The main objective of this paper is to evaluate the role of hydraulic retention time (HRT) and granular medium in faecal coliform (FC) and somatic coliphage (SC) removal in tertiary reed beds. Experiments were carried out in a pilot plant with four parallel reed beds (horizontal subsurface flow constructed wetlands), each one containing a different type of granular medium. This pilot plant is located in a wastewater treatment plant in Montcada i Reixac, near Barcelona, in northeastern Spain. The microbial inactivation ratios obtained in the different beds are compared as a function of three selected HRTs. Secondary effluent from the wastewater treatment plant was used as the influent of the pilot system. The microbial inactivation ratio ranged between 0.1 and 2.7 log-units for FC and from 0.5 to 1.7 log-units for SC in beds with coarser granular material (5-25mm), while it ranged between 0.7 and 3.4 log-units for FC and from 0.9 to 2.6 log-units for SC in the bed with finer material (2-13mm). HRT and granular medium are both key factors in microbial removal in the tertiary reed beds. The microbial inactivation ratio rises as the HRT increases until it reaches a saturation value (in general at an HRT of 3 days). The value of the microbial inactivation ratio at the saturation level depends on the granular medium contained in the bed. The specific surface area necessary to reach 2-3 log-units of FC and SC is approximately 3m(2)/person-equivalent.

Analysis of the implementation of a sand bed type filter for the venting of a nuclear power plant

International Nuclear Information System (INIS)

Cuevas V, D.; Sainz M, E.; Ortiz V, J.

2017-09-01

The filtered venting of the containment has been adopted in European countries to mitigate the consequences derived from the excess pressure of the containment during a severe accident. When venting has taken place, the fission products are released directly into the environment, unless a filter is placed in the path of the same, so various types of filters are used to trap the fission products. The containment venting filters currently installed use different filtering technologies that involve more than one medium. Those who use water as the first stage of filtration are called wet systems, are equipped with additional stages to eliminate water drops and emissions of fine aerosols, and may even be equipped with an element that contains certain means of absorption for the gaseous iodine species filtration. Other designs, based on deep bed filtration as the main retention stage, called dry filters; use metal fiber, ceramic or sand filtration media to trap aerosols. The present work evaluates the hydraulic characteristics of the sand bed type filter designed by EDF as a candidate to be installed in the containment of the BWR Mark II (primary containment type of the Laguna Verde nuclear power plant). The evaluation of the sand bed filter was performed using the OpenFOAM open source software package. Models of each zone of the filtering device were generated and by means of a series of parametric calculations of computational fluid mechanics, the relevant hydrodynamic characteristics of the device were obtained, such as pressure drops against mass flow and pressure fields and velocity under different operating conditions. On the other hand, the validation of the sand bed filter model was made when comparing the results of experimental tests carried out in a sand column of the PITEAS program (1985-1986) against the simulation in OpenFOAM. The results obtained are very close to those obtained experimentally. (Author)

Sulphate issues and learning for secondary loop system at Dayabay Nuclear Power Plant

International Nuclear Information System (INIS)

Wang Changchun; Fang Jun; Yao Xuehong; He Yanhong; Chen Bin

2014-01-01

Dayabay NPP started up from 1994. There is no condensate polishing system (CPP) with initial design. Unfortunately there happened few times serious issues with sea water leakage into condensate. It was reconstructed and be added CPP from 1997. But we found sulphate concentration in SG will increased after ATE was put into operating, when CPP was out of service, then sulphate concentration decreased. Through the study and research for a few years, we found the root cause and we took these following improvements at site step by step, steam generation blow down water quality was significantly improved: Optimize feed water distribution condition in resin bed. Since the shortcomings of resin bed design, resin is moving up and down during operating. To prevent resin re-separation and broken issue, we improved the structure of feed distribution and better the resin condition in resin bed; Optimize regeneration process. Optimize mixed bed resin transferring, separation, regeneration process, re-separation and re-mixing process during regeneration; Optimize operating process. Regular clean resin beads under the water chamber and resin trap to prevent resin leak into SG system; Other actions. Check nozzles one by one in resin bed and change these nozzles with shortcomings to prevent resin leakage into resin chamber. Upgrade cation resin type from 12% DVB to 16% DVB. According to Dayabay nuclear power plant steam generator sulphate issue experience, now in China we have improved a lot for the secondary loop condensate polishing system design, equipment manufacturing, operation process, etc. We have achieved good results in our new projects such as LingAo Phase II nuclear power plant. (author)

Trends in Infant Bedding Use: National Infant Sleep Position Study, 1993–2010

Science.gov (United States)

Colson, Eve R.; Willinger, Marian; Rybin, Denis V.; Camperlengo, Lena; Corwin, Michael J.

2015-01-01

BACKGROUND: Use of potentially hazardous bedding, as defined by the American Academy of Pediatrics (eg, pillows, quilts, comforters, loose bedding), is a modifiable risk factor for sudden infant death syndrome and unintentional sleep-related suffocation. The proportion of US infants sleeping with these types of bedding is unknown. METHODS: To investigate the US prevalence of and trends in bedding use, we analyzed 1993–2010 data from the National Infant Sleep Position study. Infants reported as being usually placed to sleep with blankets, quilts, pillows, and other similar materials under or covering them in the last 2 weeks were classified as bedding users. Logistic regression was used to describe characteristics associated with bedding use. RESULTS: From 1993 to 2010, bedding use declined but remained a widespread practice (moving average of 85.9% in 1993–1995 to 54.7% in 2008–2010). Prevalence was highest for infants of teen-aged mothers (83.5%) and lowest for infants born at term (55.6%). Bedding use was also frequently reported among infants sleeping in adult beds, on their sides, and on a shared surface. The rate of decline in bedding use was markedly less from 2001–2010 compared with 1993–2000. For 2007 to 2010, the strongest predictors (adjusted odds ratio: ≥1.5) of bedding use were young maternal age, non-white race and ethnicity, and not being college educated. CONCLUSIONS: Bedding use for infant sleep remains common despite recommendations against this practice. Understanding trends in bedding use is important for tailoring safe sleep interventions. PMID:25452654

Influence of plane bed on the force exerted on a cylinder oscillating in still water

Energy Technology Data Exchange (ETDEWEB)

Naeeni, S.T.O. [Tehran Univ., Dept. of Civil Engineering, Tehran (Iran); Narayanan, R. [Universiti Teknologi Malaysia, Faculty of Civil Engineering, Johor Bahru (Malaysia)

2005-12-01

The wall pressure field on a cylinder oscillating over a plane bed in still water is reported in this paper. Two gaps between the cylinder and the bed were considered. Pressures on the periphery of the cylinder were measured by a transducer and were found to be essentially repeatable from one cycle to the next. The forces determined from the pressure profiles compare well with those measured directly by a force transducer except significantly at Keulegan-Carpenter number of 15.0. The importance of the plane bed when it is stationary or moving with the cylinder is examined. The significance of the roughness of the bed with respect to the oscillatory forces exerted on the cylinder is also assessed. (Author)

Fluidized-bed calcination of simulated commercial high-level radioactive wastes

International Nuclear Information System (INIS)

Freeby, W.A.

1975-11-01

Work is in progress at the Idaho Chemical Processing Plant to verify process flowsheets for converting simulated commercial high-level liquid wastes to granular solids using the fluidized-bed calcination process. Primary emphasis in the series of runs reported was to define flowsheets for calcining simulated Allied-General Nuclear Services (AGNS) waste and to evaluate product properties significant to calcination, solids storage, or post treatment. Pilot-plant studies using simulated high-level acid wastes representative of those to be produced by Nuclear Fuel Services, Inc. (NFS) are also included. Combined AGNS high-level and intermediate-level waste (0.26 M Na in blend) was successfully calcined when powdered iron was added (to result in a Na/Fe mole ratio of 1.0) to the feed to prevent particle agglomeration due to sodium nitrate. Long-term runs (approximately 100 hours) showed that calcination of the combined waste is practical. Concentrated AGNS waste containing sodium at concentrations less than 0.2 M were calcined successfully; concentrated waste containing 1.13 M Na calcined successfully when powdered iron was added to the feed to suppress sodium nitrate formation. Calcination of dilute AGNS waste by conventional fluid-bed techniques was unsuccessful due to the inability to control bed particle size--both particle size and bed level decreased. Fluid-bed solidification of AGNS dilute waste at conditions in which most of the calcined solids left the calciner vessel with the off-gas was successful. In such a concept, the steady-state composition of the bed material would be approximately 22 wt percent calcined solids deposited on inert particles. Calcination of simulated NFS acid waste indicated that solidification by the fluid-bed process is feasible

Exploration of probability distribution of velocities of saltating sand particles based on the stochastic particle-bed collisions

International Nuclear Information System (INIS)

Zheng Xiaojing; Xie Li; Zhou Youhe

2005-01-01

The wind-blown sand saltating movement is mainly categorized into two mechanical processes, that is, the interaction between the moving sand particles and the wind in the saltation layer, and the collisions of incident particles with sand bed, and the latter produces a lift-off velocity of a sand particle moving into saltation. In this Letter a methodology of phenomenological analysis is presented to get probability density (distribution) function (pdf) of the lift-off velocity of sand particles from sand bed based on the stochastic particle-bed collision. After the sand particles are dealt with by uniform circular disks and a 2D collision between an incident particle and the granular bed is employed, we get the analytical formulas of lift-off velocity of ejected and rebound particles in saltation, which are functions of some random parameters such as angle and magnitude of incident velocity of the impacting particles, impact and contact angles between the collision particles, and creeping velocity of sand particles, etc. By introducing the probability density functions (pdf's) of these parameters in communion with all possible patterns of sand bed and all possible particle-bed collisions, and using the essential arithmetic of multi-dimension random variables' pdf, the pdf's of lift-off velocities are deduced out and expressed by the pdf's of the random parameters in the collisions. The numerical results of the distributions of lift-off velocities display that they agree well with experimental ones

Compressor Has No Moving Macroscopic Parts

Science.gov (United States)

Gasser, Max

1995-01-01

Compressor containing no moving macroscopic parts functions by alternating piston and valve actions of successive beds of magnetic particles. Fabricated easily because no need for precisely fitting parts rotating or sliding on each other. Also no need for lubricant fluid contaminating fluid to be compressed. Compressor operates continuously, eliminating troublesome on/off cycling of other compressors, and decreasing consumption of energy. Phased cells push fluid from bottom to top, adding increments of pressure. Each cell contains magnetic powder particles loose when electromagnet coil deenergized, but tightly packed when coil energized.

Employment of fluidized bed ash as a basecourse material; Ryudosho nenshobai wo genryo to shita robanzai no jitsuyoka

Energy Technology Data Exchange (ETDEWEB)

Ishihara, I [Center for Coal Utilization, Japan, Tokyo (Japan); Tsuzura, K [Naruto Salt Mfg. Co. Ltd., Tokushima (Japan); Izumi, H [Nippon Hodo Co. Ltd., Tokyo (Japan); Goto, H [Electric Power Development Co. Ltd., Tokyo (Japan); Nagaoka, S [Kawasaki Heavy Industries, Ltd., Kobe (Japan)

1996-09-01

Generation of coal ash from coal burning fluidized beds reaches 400,000 tons annually, which is anticipated to increase still more in the future. This paper relates to works to develop a basecourse material manufacturing technology by utilizing excellent hydration and solidification characteristics of fluidized bed ash. The developmental works have been moved forward as a subsidy operation of the Agency of Natural Resources and Energy. Upon having obtained a prospect of practical application of the development, the research results are reported in this paper. Coal ash produced in a fluidized bed boiler goes through the following processes: it is added with water and kneaded; formed into rectangular parallelepiped having sides of 10 to 30 cm long by using a forming machine of vibrating and pressurizing type; cured in steam at 60 degC; crushed into sizes smaller than 40 mm; and made into a basecourse material upon adjusting the grain size. A pilot plant completed in 1993 has produced 15,000 tons of the material to date. Properties required as a basecourse material, such as hazardous metal dissolving characteristics and strength sufficiently meet relevant standards or the targeted value. Demonstration tests of the material on roads including public roads have shown as good result as those obtained from standard basecourse materials. 8 refs., 8 figs., 7 tabs.

Variable and space steps solution of a two phase moving boundary ...

African Journals Online (AJOL)

Equations of a two phase moving boundary problem in cylindrical coordinates are obtained from the formulation of a transient shrinking core model of whole tree combustion in a one dimensional steady state fixed-bed reactor. An hybrid Variable Grid Method is developed to solve the non linear equations and the results are ...

Consideration of emergency source terms for pebble-bed high temperature gas-cooled reactor

International Nuclear Information System (INIS)

Tao, Liu; Jun, Zhao; Jiejuan, Tong; Jianzhu, Cao

2009-01-01

Being the last barrier in the nuclear power plant defense-in-depth strategy, emergency planning (EP) is an integrated project. One of the key elements in this process is emergency source terms selection. Emergency Source terms for light water reactor (LWR) nuclear power plant (NPP) have been introduced in many technical documents, and advanced NPP emergency planning is attracting attention recently. Commercial practices of advanced NPP are undergoing in the world, pebble-bed high-temperature gas-cooled reactor (HTGR) power plant is under construction in China which is considered as a representative of advanced NPP. The paper tries to find some pieces of suggestion from our investigation. The discussion of advanced NPP EP will be summarized first, and then the characteristics of pebble-bed HTGR relating to EP will be described. Finally, PSA insights on emergency source terms selection and current pebble-bed HTGR emergency source terms suggestions are proposed

Using multiple bed load measurements: Toward the identification of bed dilation and contraction in gravel-bed rivers

Science.gov (United States)

Marquis, G. A.; Roy, A. G.

2012-02-01

This study examines bed load transport processes in a small gravel-bed river (Béard Creek, Québec) using three complementary methods: bed elevation changes between successive floods, bed activity surveys using tags inserted into the bed, and bed load transport rates from bed load traps. The analysis of 20 flood events capable of mobilizing bed material led to the identification of divergent results among the methods. In particular, bed elevation changes were not consistent with the bed activity surveys. In many cases, bed elevation changes were significant (1 to 2 times the D50) even if the bed surface had not been activated during the flood, leading to the identification of processes of bed dilation and contraction that occurred over 10% to 40% of the bed surface. These dynamics of the river bed prevent accurate derivation of bed load transport rates from topographic changes, especially for low magnitude floods. This paper discusses the mechanisms that could explain the dilation and contraction of particles within the bed and their implications in fluvial dynamics. Bed contraction seems to be the result of the winnowing of the fine sediments under very low gravel transport. Bed dilation seems to occur on patches of the bed at the threshold of motion where various processes such as fine sediment infiltration lead to the maintenance of a larger sediment framework volume. Both processes are also influenced by flood history and the initial local bed state and in turn may have a significant impact on sediment transport and morphological changes in gravel-bed rivers.

Bed-Deformation Experiments Beneath a Temperate Glacier

Science.gov (United States)

Iverson, N. R.; Hooyer, T. S.; Fischer, U. H.; Cohen, D.; Jackson, M.; Moore, P. L.; Lappegard, G.; Kohler, J.

2002-12-01

Fast flow of glaciers and genesis of glacial landforms are commonly attributed to shear deformation of subglacial sediment. Although models of this process abound, data gathered subglacially on the kinematics and mechanics of such deformation are difficult to interpret. Major difficulties stem from the necessity of either measuring deformation near glacier margins, where conditions may be abnormal, or at the bottoms of boreholes, where the scope of instrumentation is limited, drilling disturbs sediment, and local boundary conditions are poorly known. A different approach is possible at the Svartisen Subglacial Laboratory, where tunnels melted in the ice provide temporary human access to the bed of Engabreen, a temperate outlet glacier of the Svartisen Ice Cap in Norway. A trough (2 m x 1.5 m x 0.5 m deep) was blasted in the rock bed, where the glacier is 220 m thick and sliding at 0.1-0.2 m/d. During two spring field seasons, this trough was filled with 2.5 tons of simulated till. Instruments in the till recorded shear (tiltmeters), volume change, total normal stress, and pore-water pressure as ice moved across the till surface. Pore pressure was brought to near the total normal stress by feeding water to the base of the till with a high-pressure pump, operated in a rock tunnel 4 m below the bed surface. Results illustrate some fundamental aspects of bed deformation. Permanent shear deformation requires low effective normal stress and hence high pore-water pressure, owing to the frictional nature of till. Shear strain generally increases upward in the bed toward the glacier sole, consistent with previous measurements beneath thinner ice at glacier margins. At low effective normal stresses, ice sometimes decouples from underlying till. Overall, bed deformation accounts for 10-35 % of basal motion, although this range excludes shear in the uppermost 0.05 m of till where shear was not measured. Pump tests with durations ranging from seconds to hours highlight the need

Proposed replacement and operation of the anhydrous hydrogen fluoride supply and fluidized-bed chemical processing systems at Building 9212, Y-12 Plant, Oak Ridge, Tennessee

International Nuclear Information System (INIS)

1995-09-01

The US Department of Energy (DOE) proposes to replace the existing anhydrous hydrogen fluoride (AHF) supply and fluidized-bed reactor systems for the Weapons Grade Highly Enriched Uranium Chemical Recovery and Recycle Facility, Building 9212, which is located within the Y-12 Plant on DOE's Oak Ridge Reservation in Oak Ridge, Tennessee. The proposed replacement system would be based upon modern design criteria and safety analyses. The replacement AHF supply and distribution system equipment would be located on the existing Dock 8/8A at Building 9212. Utilities would be extended to the dock to service the process equipment. The following process equipment modules would be prefabricated for installation at the modified dock: an AHF cylinder enclosure, an AHF supply manifold and vaporizer module, an AHF sump tank and transfer skid, and an AHF supply off-gas scrubber assembly module. The fluidized-bed reactor system would be constructed in an area adjacent to the existing system in Building 9212. The replacement equipment would consist of a new reduction fluidized-bed reactor, a hydrofluorination fluidized-bed reactor, and associated air emission control equipment. The no-action alternative, which is the continued operation of the existing AHF supply and fluidized-bed reactor systems, was also evaluated

Steam and sodium leak simulation in a fluidized-bed steam generator

International Nuclear Information System (INIS)

Vaux, W.G.; Keeton, A.R.; Keairns, D.L.

1977-01-01

A fluidized-bed steam generator for the liquid metal fast breeder reactor enhances plant availability and minimizes the probability of a water/sodium reaction. An experimental test program was conceived to assess design criteria and fluidized-bed operation under conditions of water, steam, and sodium leaks. Sodium, steam, and water were leaked into helium-fluidized beds of metal and ceramic particles at 900 F. Test results show the effects of leaks on the heat transfer coefficient, quality of fluidization, leak detection, and cleanup procedures

Fluidized bed gasification of selected South African coals

CSIR Research Space (South Africa)

Engelbrecht, AD

2010-05-01

Full Text Available that due to the good heat and mass transfer properties of fluidised beds, coal with ash contents up to 70% can be utilised. The CSIR’s research and development work resulted in the installation of five bubbling fluidised bed combustors (BFBCs) between... 1989 and 1999. Other companies, such as Babcock and Scientific Design, also installed a number of BFBC plants during this time. It was realised during the development of BFBC technology that due to the low lateral dispersion coefficient of coal...

Particle flow of ceramic breeder pebble beds in bi-axial compression experiments

International Nuclear Information System (INIS)

Hermsmeyer, S.; Reimann, J.

2002-01-01

Pebble beds of Tritium breeding ceramic material are investigated within the framework of developing solid breeder blankets for future nuclear fusion power plants. For the thermo-mechanical characterisation of such pebble beds, bed compression experiments are the standard tools. New bi-axial compression experiments on 20 and 30 mm high pebble beds show pebble flow effects much more pronounced than in previous 10 mm beds. Owing to the greater bed height, conditions are reached where the bed fails in cross direction and unhindered flow of the pebbles occurs. The paper presents measurements for the orthosilicate and metatitanate breeder materials that are envisaged to be used in a solid breeder blanket. The data are compared with calculations made with a Drucker-Prager soil model within the finite-element code ABAQUS, calibrated with data from other experiments. It is investigated empirically whether internal bed friction angles can be determined from pebble beds of the considered heights, which would simplify, and broaden the data base for, the calibration of the Drucker-Prager pebble bed models

Pressurized fluidized-bed combustion technology exchange workshop

Energy Technology Data Exchange (ETDEWEB)

,

1980-04-01

The pressurized fluidized-bed combustion technology exchange workshop was held June 5 and 6, 1979, at The Meadowlands Hilton Hotel, Secaucus, New Jersey. Eleven papers have been entered individually into EDB and ERA. The papers include reviews of the US DOE and EPRI programs in this area and papers by Swedish, West German, British and American organizations. The British papers concern the joint program of the USA, UK and FRG at Leatherhead. The key factor in several papers is the use of fluidized bed combustors, gas turbines, and steam turbines in combined-cycle power plants. One paper examines several combined-cycle alternatives. (LTN)

Vasorelaxation induced by common edible tropical plant extracts in isolated rat aorta and mesenteric vascular bed.

Science.gov (United States)

Runnie, I; Salleh, M N; Mohamed, S; Head, R J; Abeywardena, M Y

2004-06-01

In this study, the vasodilatory actions of nine edible tropical plant extracts were investigated. Ipomoea batatas (sweet potato leaf), Piper betle (betel leaf), Anacardium occidentale (cashew leaf), Gynandropsis gynandra (maman leaf), Carica papaya (papaya leaf), and Mentha arvensis (mint leaf) extracts exhibited more than 50% relaxing effect on aortic ring preparations, while Piper betle and Cymbopogon citratus (lemongrass stalk) showed comparable vasorelaxation on isolated perfused mesenteric artery preparation. The vascular effect on the aortic ring preparations were mainly endothelium-dependent, and mediated by nitric oxide (NO) as supported by the inhibition of action in the presence of N(omega)-nitro-L-arginine (NOLA), an nitric oxide synthase (NOS) inhibitor, or by the removal of endothelium. In contrast, vasodilatory actions in resistance vessels (perfused mesenteric vascular beds) appear to involve several biochemical mediators, including NO, prostanoids, and endothelium-dependent hyperpolarizing factors (EDHFs). Total phenolic contents and antioxidant capacities varied among different extracts and found to be independent of vascular relaxation effects. This study demonstrates that many edible plants common in Asian diets to possess potential health benefits, affording protection at the vascular endothelium level.

Integrated drying and incineration of wet sewage sludge in combined bubbling and circulating fluidized bed units.

Science.gov (United States)

Li, Shiyuan; Li, Yunyu; Lu, Qinggang; Zhu, Jianguo; Yao, Yao; Bao, Shaolin

2014-12-01

An original integrated drying and incineration technique is proposed to dispose of sewage sludge with moisture content of about 80% in a circulating fluidized bed. This system combines a bubbling fluidized bed dryer with a circulating fluidized bed incinerator. After drying, sewage sludge with moisture less than 20% is transported directly and continuously from the fluidized bed dryer into a circulating fluidized bed incinerator. Pilot plant results showed that integrated drying and incineration is feasible in a unique single system. A 100 t/d Sewage Sludge Incineration Demonstration Project was constructed at the Qige sewage treatment plant in Hangzhou City in China. The operational performance showed that the main operation results conformed to the design values, from which it can be concluded that the scale-up of this technique is deemed both feasible and successful. Copyright © 2014 Elsevier Ltd. All rights reserved.

[Special beds. Pulmonary therapy system].

Science.gov (United States)

Calixto Rodríguez, Joaquín; Rodríguez Martínez, Xavier; Marín i Vivó, Gemma; Paunellas Albert, Josep

2008-10-01

To be bedridden reduces one's capacity to move and produces muscular debility that affects the respiratory system leading to a decreased effectiveness in expectoration, the ability to spit up sputum. The pulmonary therapy system integrated in a bed is the result of applying motorized elements to the articulation points of the bad in order to achieve safe positions at therapeutic angles, which improve the breathing-perfusion (blood flow) relationship. This system also makes it possible to apply vibration waves to the patient which favor the elimination of bronchial-pulmonary secretions, the rehabilitation of the bedridden patient and decrease the work load for nursing personnel.

A New Method for Tracking Individual Particles During Bed Load Transport in a Gravel-Bed River

Science.gov (United States)

Tremblay, M.; Marquis, G. A.; Roy, A. G.; Chaire de Recherche Du Canada En Dynamique Fluviale

2010-12-01

Many particle tracers (passive or active) have been developed to study gravel movement in rivers. It remains difficult, however, to document resting and moving periods and to know how particles travel from one deposition site to another. Our new tracking method uses the Hobo Pendant G acceleration Data Logger to quantitatively describe the motion of individual particles from the initiation of movement, through the displacement and to the rest, in a natural gravel river. The Hobo measures the acceleration in three dimensions at a chosen temporal frequency. The Hobo was inserted into 11 artificial rocks. The rocks were seeded in Ruisseau Béard, a small gravel-bed river in the Yamaska drainage basin (Québec) where the hydraulics, particle sizes and bed characteristics are well known. The signals recorded during eight floods (Summer and Fall 2008-2009) allowed us to develop an algorithm which classifies the periods of rest and motion. We can differentiate two types of motion: sliding and rolling. The particles can also vibrate while remaining in the same position. The examination of the movement and vibration periods with respect to the hydraulic conditions (discharge, shear stress, stream power) showed that vibration occurred mostly before the rise of hydrograph and allowed us to establish movement threshold and response times. In all cases, particle movements occurred during floods but not always in direct response to increased bed shear stress and stream power. This method offers great potential to track individual particles and to establish a spatiotemporal sequence of the intermittent transport of the particle during a flood and to test theories concerning the resting periods of particles on a gravel bed.

Forces on stationary particles in near-bed turbulent flows

Science.gov (United States)

Schmeeckle, Mark W.; Nelson, Jonathan M.; Shreve, Ronald L.

2007-06-01

In natural flows, bed sediment particles are entrained and moved by the fluctuating forces, such as lift and drag, exerted by the overlying flow on the particles. To develop a better understanding of these forces and the relation of the forces to the local flow, the downstream and vertical components of force on near-bed fixed particles and of fluid velocity above or in front of them were measured synchronously at turbulence-resolving frequencies (200 or 500 Hz) in a laboratory flume. Measurements were made for a spherical test particle fixed at various heights above a smooth bed, above a smooth bed downstream of a downstream-facing step, and in a gravel bed of similarly sized particles as well as for a cubical test particle and 7 natural particles above a smooth bed. Horizontal force was well correlated with downstream velocity and not correlated with vertical velocity or vertical momentum flux. The standard drag formula worked well to predict the horizontal force, but the required value of the drag coefficient was significantly higher than generally used to model bed load motion. For the spheres, cubes, and natural particles, average drag coefficients were found to be 0.76, 1.36, and 0.91, respectively. For comparison, the drag coefficient for a sphere settling in still water at similar particle Reynolds numbers is only about 0.4. The variability of the horizontal force relative to its mean was strongly increased by the presence of the step and the gravel bed. Peak deviations were about 30% of the mean force for the sphere over the smooth bed, about twice the mean with the step, and 4 times it for the sphere protruding roughly half its diameter above the gravel bed. Vertical force correlated poorly with downstream velocity, vertical velocity, and vertical momentum flux whether measured over or ahead of the test particle. Typical formulas for shear-induced lift based on Bernoulli's principle poorly predict the vertical forces on near-bed particles. The

Process and technological wastes compaction through a fluidized bed incineration process

International Nuclear Information System (INIS)

Guiroy, J.J.

1993-01-01

The various fluidized bed systems (dense or circulating) are reviewed and the advantages of the circulation fluidized bed are highlighted (excellent combustion performance, clean combustion, large operating range, poly-functionality with regards to waste type, ...). Applications to contaminated graphite (with the problem of ash management) and to plant process wastes (ion exchangers, technological wastes, aqueous effluents); study of the neutralization and chlorine emission

Catalytic wet air oxidation of coke-plant wastewater on ruthenium-based eggshell catalysts in a bubbling bed reactor.

Science.gov (United States)

Yang, M; Sun, Y; Xu, A H; Lu, X Y; Du, H Z; Sun, C L; Li, C

2007-07-01

Catalytic wet air of coke-plant wastewater was studied in a bubbling bed reactor. Two types of supported Ru-based catalysts, eggshell and uniform catalysts, were employed. Compared with the results in the wet air oxidation of coke-plant wastewater, supported Ru uniform catalysts showed high activity for chemical oxygen demand (COD) and ammonia/ammonium compounds (NH3-N) removal at temperature of 250 degrees C and pressure of 4.8 MPa, and it has been demonstrated that the catalytic activity of uniform catalyst depended strongly on the distribution of active sites of Ru on catalyst. Compared to the corresponding uniform catalysts with the same Ru loading (0.25 wt.% and 0.1 wt.%, respectively), the eggshell catalysts showed higher activities for CODcr removal and much higher activities for NH3-N degradation. The high activity of eggshell catalyst for treatment of coke-plant wastewater can be attributed to the higher density of active Ru sites in the shell layer than that of the corresponding uniform catalyst with the same Ru loading. It has been also evidenced that the active Ru sites in the internal core of uniform catalyst have very little or no contribution to CODcr and NH3-N removal in the total oxidation of coke-plant wastewater.

Material control system design: Test Bed Nitrate Storage Area (TBNSA)

International Nuclear Information System (INIS)

Clark, G.A.; Da Roza, R.A.; Dunn, D.R.; Sacks, I.J.; Harrison, W.; Huebel, J.G.; Ross, W.N.; Salisbury, J.D.; Sanborn, R.H.; Weissenberger, S.

1978-05-01

This report provides an example of a hypothetical Special Nuclear Material (SNM) Safeguard Material Control and Accounting (MC and A) System which will be used as a subject for the demonstration of the Lawrence Livermore Laboratory MC and A System Evaluation Methodology in January 1978. This methodology is to become a tool in the NRC evaluation of license applicant submittals for Nuclear Fuel Cycle facilities. The starting point for this test bed design was the Allied-General Nuclear Services--Barnwell Nuclear Fuel Plant Reprocessing plant as described in the Final Safety Analysis Report (FSAR), of August 1975. The test bed design effort was limited to providing an SNM safeguard system for the plutonium nitrate storage area of this facility

Fluidised bed technology – Applications and R&D in Southern Africa

CSIR Research Space (South Africa)

North, BC

2007-06-28

Full Text Available Bed area : 25 m2 Plant purpose : A 10 MW plant for the combustion of duff coal at greater than 98 % burnout to provide hot gases for drying slag. Subsequently also used for organic waste incineration. Project duration : 1988 to 1989 Current...

Dryout heat flux experiments with deep heterogeneous particle bed

International Nuclear Information System (INIS)

Lindholm, I.; Holmstroem, S.; Miettinen, J.; Lestinen, V.; Hyvaerinen, J.; Pankakoski, P.; Sjoevall, H.

2006-01-01

A test facility has been constructed at Technical Research Centre of Finland (VTT) to simulate as accurately as possible the ex-vessel core particle bed in the conditions of Olkiluoto nuclear power plant. The STYX particle bed reproduces the anticipated depth of the bed and the size range of particles having irregular shape. The bed is immersed in water, creating top flooding conditions, and internally heated by an array of electrical resistance heating elements. Dryout tests have been successfully conducted at 0.1-0.7 MPa pressure for both uniformly mixed and stratified bed geometries. In all tests, including the stratified ones, the dry zone first formed near the bottom of the bed. The measured dryout heat fluxes increased with increasing pressure, from 232 kW/m 2 at near atmospheric pressure to 451 kW/m 2 at 0.7 MPa pressure. The data show some scatter even for the uniform bed. The tests with the stratified bed indicate a clear reduction of critical power due to the presence of a layer of small particles on top of the uniform bed. Comparison of data with various critical power (dryout heat flux) correlations for porous media shows that the most important parameter in the models is the effective particle diameter. Adiabatic debris bed flow resistance measurements were conducted to determine the most representative particle diameter. This diameter is close, but not equal, to the particle number-weighted average diameter of the bed material. With it, uniform bed data can be calculated to within an accuracy of 3-28% using Lipinski's 0-D model. In the stratified bed experiments, it appears that the top layer was partially fluidized, hence the measured critical power was significantly higher than calculated. Future experiments are being planned with denser top layer material to eliminate non-prototypic fluidization

Technical and economic assessment of fluidized-bed-augmented compressed-air energy-storage system: system load following capability

Energy Technology Data Exchange (ETDEWEB)

Lessard, R.D.; Blecher, W.A.; Merrick, D.

1981-09-01

The load-following capability of fluidized bed combustion-augmented compressed air energy storage systems was evaluated. The results are presented in two parts. The first part is an Executive Summary which provides a concise overview of all major elements of the study including the conclusions, and, second, a detailed technical report describing the part-load and load following capability of both the pressurized fluid bed combustor and the entire pressurized fluid bed combustor/compressed air energy storage system. The specific tasks in this investigation were to: define the steady-state, part-load operation of the CAES open-bed PFBC; estimate the steady-state, part-load performance of the PFBC/CAES system and evaluate any possible operational constraints; simulate the performance of the PFBC/CAES system during transient operation and assess the load following capability of the system; and establish a start-up procedure for the open-bed PFBC and evaluate the impact of this procedure. The conclusions are encouraging and indicate that the open-bed PFBC/CAES power plant should provide good part-load and transient performance, and should have no major equipment-related constraints, specifically, no major problems associated with the performance or design of either the open-end PFBC or the PFBC/CAES power plant in steady-state, part-load operation are envisioned. The open-bed PFBC/CAES power plant would have a load following capability which would be responsive to electric utility requirements for a peak-load power plant. The open-bed PFBC could be brought to full operating conditions within 15 min after routine shutdown, by employing a hot-start mode of operation. The PFBC/CAES system would be capable of rapid changes in output power (12% of design load per minute) over a wide output power range (25% to 100% of design output). (LCL)

About the gasification of untreated scrap and waste wood in fluidized bed reactor for use in decentralized gas engine-cogeneration plants; Zur Vergasung von Rest- und Abfallholz in Wirbelschichtreaktoren fuer dezentrale Energieversorgungsanlagen

Energy Technology Data Exchange (ETDEWEB)

Tepper, H.

2005-10-20

This dissertation examines the thermochemical conversion (gasification) of untreated scrap and waste wood in combustible gases for use in decentralized gas engine-cogeneration plants of low output (1 to 10 MW fuel power). A general section goes into the basics of the energetic utilization of solid biomass, the subprocesses of thermochemical conversion being described in more detail. Special attention is given to the processes and state of the art of biomass gasification in decentralized plants. A theoretical section analyzes the gasification models for solid biomass presented in the literature. Based on this analysis, a simplified kinetic model is derived for the gasification of untreated scrap and waste wood with air in bubbling fluidized bed reactors. It includes a fluid mechanic analysis of the fluidized bed based on HILLIGARDT, an empirical pyrolysis model and a global kinetic approach to the main chemical reaction taken from the literature. An experimental section describes the tests of the gasification of forest scrap wood in a semi-industrial fluidized bed gasification test plant with 150 kW fuel power and presents the significant test results. The gasification model derived is applied to check the test plant's standard settings and compare them with measured values. Furthermore, the model is employed to explain basic reaction paths and zones and to perform concluding parameter simulations. (orig.)

Environmental assessment of the atlas bio-energy waste wood fluidized bed gasification power plant. Final report

Energy Technology Data Exchange (ETDEWEB)

Holzman, M.I.

1995-08-01

The Atlas Bio-Energy Corporation is proposing to develop and operate a 3 MW power plant in Brooklyn, New York that will produce electricity by gasification of waste wood and combustion of the produced low-Btu gas in a conventional package steam boiler coupled to a steam-electric generator. The objectives of this project were to assist Atlas in addressing the environmental permit requirements for the proposed power plant and to evaluate the environmental and economic impacts of the project compared to more conventional small power plants. The project`s goal was to help promote the commercialization of biomass gasification as an environmentally acceptable and economically attractive alternative to conventional wood combustion. The specific components of this research included: (1) Development of a permitting strategy plan; (2) Characterization of New York City waste wood; (3) Characterization of fluidized bed gasifier/boiler emissions; (4) Performance of an environmental impact analysis; (5) Preparation of an economic evaluation; and (6) Discussion of operational and maintenance concerns. The project is being performed in two phases. Phase I, which is the subject of this report, involves the environmental permitting and environmental/economic assessment of the project. Pending NYSERDA participation, Phase II will include development and implementation of a demonstration program to evaluate the environmental and economic impacts of the full-scale gasification project.

Optimal planting systems for cut gladiolus and stock production

Directory of Open Access Journals (Sweden)

Iftikhar Ahmad

2017-10-01

Full Text Available A study was conducted to elucidate the effect of different planting systems, videlicet (viz. flat, ridge, and raised bed system on growth, yield and quality of gladiolus and stock. Corms of ‘Rose Supreme’ and ‘White Prosperity’ gladiolus and seedlings of ‘Cheerful White’, ‘Lucinda Dark Rose Double’ and ‘Lucinda Dark Rose Single’ stock were planted on different planting systems in individual experiments for each species. Gladiolus had similar good quality production irrespective of planting systems with numerical superiority of ridge planting, which produced longer stems with higher stem fresh weight, but delayed corm sprouting by ca. 1 d compared to raised bed or flat planting system. Among cultivars, ‘Rose Supreme’ produced higher number of florets per spike, taller stems with longer spikes, higher fresh weight of stems and higher number of cormels than ‘White Prosperity’. Stock plants grown on flat beds produced stems with greater stem length, leaf area and fresh weight of stems compared to ridge or raised bed planting systems. Plants grown on ridges produced the highest stem diameter, number of leaves per plant, total leaf chlorophyll contents, and number of flowers per spike. ‘Cheerful White’ and ‘Lucinda Dark Rose Double’ performed best by producing good quality stems in shorter period compared to ‘Lucinda Dark Rose Single’. In summary, gladiolus should be grown on ridges, while stock may be planted on flat beds for higher yields of better quality flowers.

Fiscal 1995 achievement report. Development of entrained bed coal gasification power plant (Part 4 - Pilot plant operation); 1995 nendo seika hokokusho. Funryusho sekitan gaska hatsuden plant kaihatsu - Sono 4. Pilot plant unten sosa hen

Energy Technology Data Exchange (ETDEWEB)

NONE

1996-03-01

The 200 tons/day entrained bed coal gasification pilot plant constructed for establishing the technology of integrated coal gasification combined cycle was subjected to operational tests, and the fiscal 1995 results are compiled. In fiscal 1995, 1328 hours and 3 minutes (8 gasification operations) was recorded with gasification furnace facility, 899 hours and 53 minutes with the gas clean-up facility, 831 hours and 27 minutes with the gas turbine facility (11 startups for the generation of 6657 MWh), and 1958 hours and 2 minutes with the treatment furnace and 1331 hours and 10 minutes with the denitration unit of the safety/environment-related facility. The details of starts and stops were described in graphs which covered Runs D13, D14-1, D14-2, E1, D15, and A14. Operating procedures were studied and compiled for the plant start/stop schedule, general guidelines, gasification furnace facility, gas clean-up facility (dry type desulfurization facility), gas clean-up facility (dry type dedusting facility), gas turbine facility, real-pressure natural-size combustor test facility, and the safety/environment-related facility. (NEDO)

The Bulgarian coal and the fluid bed technology

International Nuclear Information System (INIS)

Konstantinov, M.; Georgiev, J.; Lebedov, K.; Petrov, N.

2000-01-01

Because of low-quality of the most of Bulgarian coal and more rigorous ecological restrictions for decreasing of greenhouse gases the fluidized bed technology is the most appropriate combustion technology. A study with a pilot plant aiming to establish the values of technological parameters in view to maintain stable process of fluidized bed combustion at the specific burning characteristics of the Bulgarian coal was carried out. Coal of different quality and particle size production of 'Marbas' LTD mines were used. Series of experiments with batches of strictly determined content were carried out at minimal, average and maximal load. The technological factors as: layer's aerodynamics, layer's height, fuel's quantity and quantity of inert material were changed at each batch. The ecological factors were optimized considering coal's quality, plant's parameters, limestone's dosing and layer's aerodynamics. A regressive model for optimization of technological and ecological factors was created. An average coefficient of performance was achieved, resp. 82.27 % at combustion of coal from mines 'Maritsa-West' and 90 % from mine 'Lev'. A coefficient of sulfur oxides' capture 70 % was obtained at coal with sulfur content 3.1-3.9 %. In conclusion the fluidized bed technology is very suitable for combustion's characteristics of the Bulgarian coal

Thermal energy storage systems using fluidized bed heat exchangers

Science.gov (United States)

Weast, T.; Shannon, L.

1980-06-01

A rotary cement kiln and an electric arc furnace were chosen for evaluation to determine the applicability of a fluid bed heat exchanger (FBHX) for thermal energy storage (TES). Multistage shallow bed FBHX's operating with high temperature differences were identified as the most suitable for TES applications. Analysis of the two selected conceptual systems included establishing a plant process flow configuration, an operational scenario, a preliminary FBHX/TES design, and parametric analysis. A computer model was developed to determine the effects of the number of stages, gas temperatures, gas flows, bed materials, charge and discharge time, and parasitic power required for operation. The maximum national energy conservation potential of the cement plant application with TES is 15.4 million barrels of oil or 3.9 million tons of coal per year. For the electric arc furnance application the maximum national conservation potential with TES is 4.5 million barrels of oil or 1.1 million tons of coal per year. Present time of day utility rates are near the breakeven point required for the TES system. Escalation of on-peak energy due to critical fuel shortages could make the FBHX/TES applications economically attractive in the future.

Modern biofuel-fired power plants in power and heat production

International Nuclear Information System (INIS)

Tuominen, J.

1993-01-01

This article gives a survey of the gasification techniques, power plant technology and boiler solutions for small power plants using biofuels. Also some experiences from commercial projects and targets of development work are presented. At present, fluidized bed combustion is by far the most important combustion technique for biomass fuels in small power plants. Compared with grate combustion, fluidized bed combustion is a distinctly more economical combustion method, and so the thermic dimensioning of a steam boiler is easier. Besides, a wider range of fuels can be used in fluidized bed combustion. Fluidized bed combustion is an excellent combustion technique for biofuels. Plenty of experience has been gained in the combustion of peat and industrial waste wood, as far as both bubbling fluidized bed combustion (BFBC) and circulating fluidized bed combustion (CFBC) are concerned. Both of the fluidized bed techniques are suitable for the combustion of biomasses

High temperature thermal energy storage in moving sand

Science.gov (United States)

Turner, R. H.; Awaya, H. I.

1978-01-01

Several high-temperature (to 500 C) heat-storage systems using sand as the storage medium are described. The advantages of sand as a storage medium include low cost for sand, widespread availability, non-toxicity, non-degradation characteristics, easy containment, and safety. The systems considered include: stationary sand with closely spaced tubes throughout the volume, the use of a fluidized bed, use of conveyor belt transporter, and the use of a blower rapid transport system. For a stationary sand bed, very close spacing of heat transfer tubes throughout the volume is required, manifesting as high power related system cost. The suggestion of moving sand past or around pipes is intended to reduce the power related costs at the penalty of added system complexity. Preliminary system cost estimates are offered. These rough calculations indicate that mobile sand heat storage systems cost less than the stationary sand approach.

FY 1989 report on the results of the development of the entrained bed coal gasification power plant. Support study for the development of the entrained bed coal gasification power plant; 1989 nendo seika hokokusho. Funryusho sekitan gaska hatsuden plant kaihatsu (Funryusho sekitan gaska hatsuden plant kaihatsu no shien kenkyu)

Energy Technology Data Exchange (ETDEWEB)

NONE

1990-05-01

For the purpose of supplying the data necessary for construction/operation/maintenance of system, gas turbine, etc. of the desulfurization/dust removal process to be adopted to a pilot plant of 200t/d entrained bed coal gasification power generation, support study was made using the Yubari 40t/d test equipment, and the FY 1989 results were summarized. As to the operation of the 40t/d gasification system, operation was stably continued, and also the system was able to feed gas to the wake device. In the high temperature dry desulfurization test, test was made on the following: structure of the sampling system of the continuous analyzer installed in the coal gas system and circulation gas system, load response corresponding control system, sequence control of the system for supplying reducing agent to SO{sub 2} reduction tower and the system for ash discharge, back washing of D-42 lift gas filter, etc. In the high temperature dry dust removal test, improvement in filtration material/dust separation performance, sequence control of the filtration material supply/discharge system, continuous dust densitometer, operational automation, etc. Through the tests, obtained were the results that are useful for the 200t/d plant. (NEDO)

Reuse of Produced Water from CO₂ Enhanced Oil Recovery, Coal-Bed Methane, and Mine Pool Water by Coal-Based Power Plants

Energy Technology Data Exchange (ETDEWEB)

Knutson, Chad [Univ. of Illinois, Champaign, IL (United States); Dastgheib, Seyed A. [Univ. of Illinois, Champaign, IL (United States); Yang, Yaning [Univ. of Illinois, Champaign, IL (United States); Ashraf, Ali [Univ. of Illinois, Champaign, IL (United States); Duckworth, Cole [Univ. of Illinois, Champaign, IL (United States); Sinata, Priscilla [Univ. of Illinois, Champaign, IL (United States); Sugiyono, Ivan [Univ. of Illinois, Champaign, IL (United States); Shannon, Mark A. [Univ. of Illinois, Champaign, IL (United States); Werth, Charles J. [Univ. of Illinois, Champaign, IL (United States)

2012-07-01

Power generation in the Illinois Basin is expected to increase by as much as 30% by the year 2030, and this would increase the cooling water consumption in the region by approximately 40%. This project investigated the potential use of produced water from CO₂ enhanced oil recovery (CO₂-EOR) operations; coal-bed methane (CBM) recovery; and active and abandoned underground coal mines for power plant cooling in the Illinois Basin. Specific objectives of this project were: (1) to characterize the quantity, quality, and geographic distribution of produced water in the Illinois Basin; (2) to evaluate treatment options so that produced water may be used beneficially at power plants; and (3) to perform a techno-economic analysis of the treatment and transportation of produced water to thermoelectric power plants in the Illinois Basin. Current produced water availability within the basin is not large, but potential flow rates up to 257 million liters per day (68 million gallons per day (MGD)) are possible if CO₂-enhanced oil recovery and coal bed methane recovery are implemented on a large scale. Produced water samples taken during the project tend to have dissolved solids concentrations between 10 and 100 g/L, and water from coal beds tends to have lower TDS values than water from oil fields. Current pretreatment and desalination technologies including filtration, adsorption, reverse osmosis (RO), and distillation can be used to treat produced water to a high quality level, with estimated costs ranging from $2.6 to $10.5 per cubic meter ($10 to $40 per 1000 gallons). Because of the distances between produced water sources and power plants, transportation costs tend to be greater than treatment costs. An optimization algorithm was developed to determine the lowest cost pipe network connecting sources and sinks. Total water costs increased with flow rate up to 26 million liters per day (7 MGD), and the range was from $4 to $16 per cubic meter

Nuclear plant owners move closer to life extension

International Nuclear Information System (INIS)

Smith, D.J.

1991-01-01

A major debate is now underway about the safety of 40-year-old nuclear power plants. Under the Atomic Energy Act of 1954 a nuclear power plant's license is limited to a maximum of 40 years. Although the act permits the renewal of an operating license, it does not outline any standards or procedures for determining when or under what conditions a plant's operating license should be renewed. This paper reports that the Electric Power Research Institute (EPRI) and the U.S. Department of Energy (DOE) are co-sponsors of a program to demonstrate the license renewal process for two nuclear power plants - Yankee Atomic Electric's 175-MW Yankee PWR plant and Northern States Power's 536-MW Monticello BWR plant. The demonstration is known as the lead plant project. Yankee Atomic has already analyzed the plant's condition and evaluated aging using computer-based expert systems and the plant's operating experience. During these tests Yankee Atomic found embrittlement of the reactor vessel

FY 1991 report on the results of the development of an entrained bed coal gasification power plant. Part 4. Operation of pilot plant; 1991 nendo seika hokokusho. Funryusho sekitan gaska hatsuden plant kaihatsu - Sono 4. Pilot plant unten sosa hen

Energy Technology Data Exchange (ETDEWEB)

NONE

1993-01-01

A record was summarized of the operation of the 200 t/d entrained bed coal gasification pilot plant that was constructed with the aim of establishing technology of the integrated coal gasification combined cycle power generation. As to the actual results of operation hours, the paper summarized the records of gasifier facilities, gas refining facilities, gas turbine facilities and safety environment facilities which were collected from April 1991 to January 1993. Relating to the actual results of start-up/stop, the paper summarized the records of gasifier facilities, gas refining facilities (desulfurization), gas refining facilities (dedusting), gas turbine facilities and safety environment facilities. Further, operation manuals were made for the schedule of plant start-up/stop, generalization, gasifier facilities, gas refining facilities (desulfurization), gas refining facilities (dedusting), gas turbine facilities, actual pressure/actual size combustor testing facilities and safety environment facilities. (NEDO)

Self-organization and chaos in a fluidized bed

International Nuclear Information System (INIS)

Daw, C.S.; Finney, C.E.A.; Vasudevan, M.; van Goor, N.A.; Nguyen, K.; Bruns, D.D.; Kostelich, E.J.; Grebogi, C.; Ott, E.; Yorke, J.A.

1995-01-01

We present experimental evidence that a complex system of particles suspended by upward-moving gas can exhibit low-dimensional bulk behavior. Specifically, we describe large-scale collective particle motion referred to as slugging in an industrial device known as a fluidized bed. As gas flow increases from zero, the bulk motion evolves from a fixed point to periodic oscillations to oscillations intermittently punctuated by ''stutters,'' which become more frequent as the flow increases further. At the highest flow tested, the behavior becomes extremely complex (''turbulent'')

Infant's bed climate and bedding in the Japanese home.

Science.gov (United States)

Nakamura Ikeda, Rie; Fukai, Kiyoko; Okamoto Mizuno, Kazue

2012-06-01

to assess the bed climate of infants in their homes in Japan. descriptive, exploratory, non-experimental research design. the data were collected at the participants' homes under normal circumstances. nineteen healthy infants between the ages of two and five months. Their mothers, who joined a parenting class organised by a maternity clinic in Okayama, Japan, consented to participate in this study. we visited the infants' homes and interviewed their mothers concerning the types and use of bedding. The temperature and relative humidity of the bed climate at the back and foot of the bedding, and in the room were measured every minute for four consecutive days. Differences among the bed climates measured during three seasons (spring, summer, and autumn) were assessed by one-way analysis of variance. The bed temperature was higher for infants than for adults. No significant difference in temperature was noted among the three seasons. The bed temperature was about 36.0°C when waterproof sheets and futon mattresses for children or adult were used. The average relative humidity of the bed climate at the back was highest in summer, followed by that in spring and autumn; the differences were significant. The use of waterproof sheets and futon mattresses for children in summer increased the relative humidity to 80% or more. The use of infant beds, sunoko drainboards, and cotton futon mattresses in summer was effective in reducing the bed humidity. these results suggest that nurse-midwives should advise the parents on comfortable bed climates for their infants, as well as how to select and use bedding for them. Copyright © 2010 Elsevier Ltd. All rights reserved.

FY 1992 report on the results of the development of an entrained bed coal gasification power plant. Part 1. Element study/Technical survey; 1992 nendo seika hokokusho. Funryusho sekitan gaska hatsuden plant kaihatsu - Sono 1. Youso kenkyu hen, gijutsu chosa hen

Energy Technology Data Exchange (ETDEWEB)

NONE

1994-02-01

For the purpose of establishing the technology of the integrated coal gasification combined cycle power generation, element study of a 200 t/d entrained bed coal gasification pilot plant was made, and the FY 1992 results were summarized. In the gasification test using a 2 t/d furnace equipment, study was made of the extraction of subjects on the operation, performance of gasification, slagging characteristics and characteristics of flux addition. In the study of slag utilization technology, chemical analysis, test on fine aggregate and test on fine particle were carried out to study applicability of the slag discharged from the entrained bed coal gasification power plant to various materials. In the study of a large gas turbine combustor for the demonstrative machine, the demonstrative machine use large gas turbine combustor testing equipment was installed at actual pressure/actual size combustion testing facilities in the pilot plant and further the test use combustor was integrated into them. By using them, the real gas combustion test was made using the adjusted coal for evaluation of combustion performance of the test use combustor. In the simulation study of the total pilot plant system, the comparative study was made between the data on the test using the actual machine and the results of the simulation. (NEDO)

Mathematical model for solid fuel combustion in fluidized bed

International Nuclear Information System (INIS)

Kostikj, Zvonimir; Noshpal, Aleksandar

1994-01-01

A mathematical model for computation of the combustion process of solid fuel in fluidized bed is presented in this work. Only the combustor part of the plant (the fluidized bed and the free board) is treated with this model. In that manner, all principal, physical presumption and improvements (upon which this model is based) are given. Finally, the results of the numerical realisation of the mathematical model for combustion of minced straw as well as the results of the experimental investigation of a concrete physical model are presented. (author)

Empirical closures for particulate debris bed spreading induced by gas–liquid flow

Energy Technology Data Exchange (ETDEWEB)

Basso, S., E-mail: simoneb@kth.se; Konovalenko, A.; Kudinov, P.

2016-02-15

Highlights: • Experimental study of the debris bed self-leveling phenomenon. • A scaling approach and a non-dimensional model to describe particle flow rate are proposed. • The model is validated against experiments with particles of different properties and at different gas injection conditions. - Abstract: Efficient removal of decay heat from the nuclear reactor core debris is paramount for termination of severe accident progression. One of the strategies is based on melt fragmentation, quenching and cooling in a deep pool of water under the reactor vessel. Geometrical configuration of the debris bed is among the important factors which determine possibility of removing the decay heat from the debris bed by natural circulation of the coolant. For instance, a tall mound-shape debris bed can be non-coolable, while the same debris can be coolable if spread uniformly. Decay heat generates a significant amount of thermal energy which goes to production of steam inside the debris bed. Two-phase flow escaping through the top layer of the bed becomes a source of mechanical energy which can move the particulate debris along the slope of the bed. The motion of the debris will lead to flattening of the bed. Such process is often called “self-leveling” phenomenon. Spreading of the debris bed by the self-leveling process can take significant time, depending on the initial debris bed configuration and other parameters. There is a competition between the time scales for reaching (i) a coolable configuration of the bed, and (ii) onset of dryout and re-melting of the debris. In the previous work we have demonstrated that the rate of particulate debris spreading is determined by local gas velocity and local slope angle of the bed. In this work we develop a scaling approach and a closure for prediction of debris spreading rate based on generalization of available experimental data. We demonstrate that introduced scaling criteria are universal for particles of different

Pressurized Fluidized Bed Combustion Second-Generation System Research and Development

Energy Technology Data Exchange (ETDEWEB)

A. Robertson; D. Horazak; R. Newby; H. Goldstein

2002-11-01

Research is being conducted under United States Department of Energy (DOE) Contract DE-AC21-86MC21023 to develop a new type of coal-fired plant for electric power generation. This new type of plant--called a Second-Generation or Advanced Pressurized Circulating Fluidized Bed Combustion (APCFB) plant--offers the promise of efficiencies greater than 45% (HHV), with both emissions and a cost of electricity that are significantly lower than conventional pulverized-coal-fired plants with scrubbers. The APCFB plant incorporates the partial gasification of coal in a carbonizer, the combustion of carbonizer char in a pressurized circulating fluidized bed boiler (PCFB), and the combustion of carbonizer syngas in a topping combustor to achieve gas turbine inlet temperatures of 2300 F and higher. A conceptual design was previously prepared for this new type of plant and an economic analysis presented, all based on the use of a Siemens Westinghouse W501F gas turbine with projected carbonizer, PCFB, and topping combustor performance data. Having tested these components at the pilot plant stage, the referenced conceptual design is being updated to reflect more accurate performance predictions together with the use of the more advanced Siemens Westinghouse W501G gas turbine and a conventional 2400 psig/1050 F/1050 F/2-1/2 in. steam turbine. This report describes the updated plant which is projected to have an HHV efficiency of 48% and identifies work completed for the October 2001 through September 2002 time period.

A design and study of the effects of selectivity on binary separation in a four-zone simulated moving bed for systems with linear isotherms

Directory of Open Access Journals (Sweden)

M.A. Cremasco

2003-06-01

Full Text Available The simulated moving bed (SMB is potentially an economical method for the separation and purification of natural products because it is a continuous processes and can achieve higher productivity, higher product recovery, and higher purity than batch chromatographic processes. Despite the advantages of SMB, one of the challenges is to specify its zone flow rates and switching time. In this case it is possible to use the standing wave analysis. In this method, in a binary system, when certain concentration waves are confined to specific zones, high product purity and yield can be assured. Appropriate zone flow rates, zone lengths and step time are chosen to achieve standing waves. In this study the effects of selectivity on yield, throughput, solvent consumption, port switching time, and product purity for a binary system are analyzed. The results show that for a given selectivity the maximum throughput decreases with increasing yield, while solvent consumption and port switching time increase with increasing yield. To achieve the same purity and yield, a system with higher selectivity has a higher throughput and lower solvent consumption.

Responses of biofilm characteristics to variations in temperature and NH4(+)-N loading in a moving-bed biofilm reactor treating micro-polluted raw water.

Science.gov (United States)

Zhang, Shuangfu; Wang, Yayi; He, Weitao; Wu, Min; Xing, Meiyan; Yang, Jian; Gao, Naiyun; Yin, Daqiang

2013-03-01

A pilot-scale moving-bed biofilm reactor (MBBR) for biological treatment of micro-polluted raw water was operated over 400days to investigate the responses of biofilm characteristics and nitrification performance to variations in temperature and NH4(+)-N loading. The mean removal efficiency of NH4(+)-N in the MBBR reached 71.4±26.9%, and batch experiments were performed to study nitrification kinetics for better process understanding. Seven physical-chemical parameters, including volatile solids (VS), polysaccharides (PS) and phospholipids (PL) increased firstly, and then rapidly decreased with increasing temperature and NH4(+)-N loading, and properly characterized the attached biomass during biofilm development and detachment in the MBBR. The biofilm compositions were described by six ratios, e.g., PS/VS and PL/VS ratios showed different variation trends, indicating different responses of PS and PL to the changes in temperature and NH4(+)-N loading. Furthermore, fluorescent in situ hybridization (FISH) analysis revealed that increased NH4(+)-N loadings caused an enrichment of the nitrifying biofilm. Copyright © 2013 Elsevier Ltd. All rights reserved.

Combustion of uraniferous lignites in fluidized bed

International Nuclear Information System (INIS)

Morales, G.; Gasos, P.

1985-01-01

In this paper a description of the continuous fluid bed combustion pilot plant unit, installed in the Junta de Energia Nuclear facilities, is presented. Besides, this paper deals with some of the studies carried out in the pilot plant aimed at the recovery of uranium from lignites, high in sulfur and ashes, coming from Calaf basin (Barcelona). These studies include the recovery of the heating value of these lignites and the reduction of environmental effect of SO 2 . Based on these studies an application exercise is presented. 9 references, 5 figures, 5 tables

Characterization of Porteresia coarctata beds along the Goa coast, India

Digital Repository Service at National Institute of Oceanography (India)

Jagtap, T.G.; Bhosale, S.H.; Charulata, S.

Porteresia coarctata, forms an important constituent in the plant succession leading to formation of mangrove communities along the estuaries in India. Major beds along the Mandovi estuary of Goa were monitored for their various ecological...

Bed Bugs

Science.gov (United States)

Prevent, identify, and treat bed bug infestations using EPA’s step-by-step guides, based on IPM principles. Find pesticides approved for bed bug control, check out the information clearinghouse, and dispel bed bug myths.

Removal of micropollutants in Moving Bed Biofilm reactors (MBBRs)

DEFF Research Database (Denmark)

Torresi, Elena

Numerous pollutants such as pharmaceuticals and personal care products are continuously released into municipal wastewater treatment plants (WWTP). Present at concentration of nano- to milligram per liter, they are defined as micropollutants. Micropollutants are only partially removed, possibly due...... compared to conventional activated sludge. In MBBRs, biofilm grow on plastic carriers kept in suspension in the reactor basin via mechanical mixing or aeration, offering a suit of benefits, amongst all comparably small footprint. Despite few existing evidences in aerobic MBBR, an in-depth understanding...

Study on transient of fluidized bed nuclear reactor

International Nuclear Information System (INIS)

Streck, E.E.

1988-01-01

The point kinetic equations for a Fluidized-Bed Nuclear Reactor are solved by the method of Hansen. Due to the time varying nature of the reactor volume, the equations have a non-conventional formulation (moving boundary problem), but the method of solution preserves its asymptotic convergence and efficiency characteristics under this formulation. A one dimensional and linearized thermal hydraulics feedback model was coupled to the point kinetic equations in order to obtain a more realistic representation of the reactor power. The resulting equations are solved by the Euler explicit method. (author)

Modeling of reaction kinetics in bubbling fluidized bed biomass gasification reactor

Energy Technology Data Exchange (ETDEWEB)

Thapa, R.K.; Halvorsen, B.M. [Telemark University College, Kjolnes ring 56, P.O. Box 203, 3901 Porsgrunn (Norway); Pfeifer, C. [University of Natural Resources and Life Sciences, Vienna (Austria)

2013-07-01

Bubbling fluidized beds are widely used as biomass gasification reactors as at the biomass gasification plant in Gussing, Austria. The reactor in the plant is a dual circulating bubbling fluidized bed gasification reactor. The plant produces 2MW electricity and 4.5MW heat from the gasification of biomass. Wood chips as biomass and olivine particles as hot bed materials are fluidized with high temperature steam in the reactor. As a result, biomass undergoes endothermic chemical reaction to produce a mixture of combustible gases in addition to some carbon-dioxide (CO2). The combustible gases are mainly hydrogen (H2), carbon monoxide (CO) and methane (CH4). The gas is used to produce electricity and heat via utilization in a gas engine. Alternatively, the gas is further processed for gaseous or liquid fuels, but still on the process of development level. Composition and quality of the gas determine the efficiency of the reactor. A computational model has been developed for the study of reaction kinetics in the gasification rector. The simulation is performed using commercial software Barracuda virtual reactor, VR15. Eulerian-Lagrangian approach in coupling of gas-solid flow has been implemented. Fluid phase is treated with an Eulerian formulation. Discrete phase is treated with a Lagrangian formulation. Particle-particle and particle-wall interactions and inter-phase heat and mass transfer have been taken into account. Series of simulations have been performed to study model prediction of the gas composition. The composition is compared with data from the gasifier at the CHP plant in Güssing, Austria. The model prediction of the composition of gases has good agreements with the result of the operating plant.

Copper electrowinning in a moving-bed cell based on reactive electrodialysis

Directory of Open Access Journals (Sweden)

Cifuentes, L.

2008-04-01

Full Text Available A two-compartment lab-scale reactive electrodialysis (RED cell with a moving particulate cathode has been used for copper electrowinning. The cathodic reaction was copper electrodeposition on a bed of copper particles forced to circulate inside a fixed cylindrical enclosure by the action of rotating paddles; the anodic reaction was ferrous to ferric ion oxidation on an anode made of static graphite bars. The anolyte (aqueous FeSO₄ + H₂SO₄ and catholyte (aqueous CuSO₄ + H₂SO₄ are kept separate by an anion membrane which prevents cation transport between the electrolytes. Experiments were carried out in order to characterize cell performance under various conditions. When operating with 40 g/L Cu (II, I = 6 A, T = 50°C, 40 rpm paddle rotation and 990 mL/min electrolyte recirculation flowrate, the specific energy consumption (SEC for copper electrowinning was 2.25 kWh/kg. An optimization of cell dimensions gave an improved SEC of 1.55 kWh/kg whereas a temperature increase from 50 to 56°C (without changing cell dimensions produced a SEC of 1.50 kWh/kg, which is 25% lower than normal values for conventional copper electrowinning cells. A comparison was drawn between the performance of this cell and a squirrel-cage cell previously developed by the authors.

Una celda a escala laboratorio de electrodiálisis reactiva (EDR, de dos compartimientos con cátodo particulado móvil, se ha utilizado para electroobtener cobre. La reacción catódica fue la electrodeposición de cobre sobre un lecho de partículas de cobre que circulan dentro de un cilindro fijo por la acción de paletas rotatorias; la reacción anódica fue la oxidación de ión ferroso a ión férrico sobre un ánodo hecho de barras de grafito estáticas. El anolito (FeSO₄ + H₂SO₄ acuoso y el catolito (CuSO₄ + H₂SO₄ acuoso se mantienen separados por una

Green Algae from Coal Bed Methane Ponds as a Source of Fertilizer for Economically Important Plants of Montana

Science.gov (United States)

Ogunsakin, O. R.; Apple, M. E.; Zhou, X.; Peyton, B.

2016-12-01

The Tongue River Basin of northeastern Wyoming and southeastern Montana is the location of natural gas reserves and coal bed methane (CBM) acreage. Although the water that emanates from CBM extraction varies with site, it is generally of higher quality than the waters produced by conventional oil and gas wells, in part because it is low in volatile organic compounds. However, since CBM water contains dissolved solids, including sodium (Na), bicarbonate (HCO3) and chloride (Cl) ions, the water must be treated before it can be discharged into the river or wetlands, or used for stock ponds or irrigation. Several ponds have been constructed to serve as a holding facility for CBM water. Algae from the CBM ponds of the Tongue River Basin have the potential to be utilized as fertilizer on economically important plants of Montana. Two very important crop plants of Montana are wheat, Triticum aestivum, and potatoes, Solanum tuberosum. To explore this potential, isolates of unicellular green algae (Chlorella sp.) from the CBM ponds were cultured in aerated vessels with Bold's Basic Growth Medium and natural and/or supplemental light. Algal biomass was condensed in and collected from a valved funnel, after which cell density was determined via light microscopy and a hemacytometer. Algal/water slurries with known nutrient contents were added to seedlings of hard winter wheat, T.aestivum, grown in a greenhouse for three months before harves. When compared to wheat provided with just water, or with water and a commercially available fertilizer, the wheat fertilized with algae had a higher chlorophyll content, more tillers (side shoots), and a higher ratio of influorescences (groups of flowers) per stem. In a related experiment, Ranger Russet seed potatoes, S. tuberosum were given just water, water and Hoagland's nutrient solution, or water with algae in order to compare aboveground growth and potato production among the treatments. The results of this study suggest that

FY 1990 report on the results of the development of the entrained bed coal gasification power plant. Part 2. Fabrication/installation of pilot plant; 1990 nendo seika hokokusho. Funryusho sekitan gaska hatsuden plant kaihatsu - Sono 2. Pilot plant seisaku suetsuke hen

Energy Technology Data Exchange (ETDEWEB)

NONE

1991-03-01

For the purpose of establishing the technology of the integrated coal gasification combined cycle power generation, fabrication/installation work, etc. were made for a pilot plant of 200t/d entrained bed coal gasification power generation, and the FY 1990 results were summarized. Construction work of a pilot plant of coal gasification power generation was at its peak in April 1990, and installation/piping work for each facility/equipment was carried out. In May, transportation/installation of gas turbine and generator were started. In June, installation of equipment of the 66kV special high voltage switching station was conducted, and the initial power receiving of 6.9kV was conducted. In August, inspection before use was made of the main piping of the gasifier equipment, gas refining equipment and gas turbine equipment. In December, trial unit operation of each equipment and interlock test were carried out. 'The integrated plant protection interlock test' was made from January 21 to February 21, 1991, and the favorable results were obtained. On February 28, a ceremony to celebrate the completion of all facilities of pilot plant was made. In March, drying of gasifier and initial firing by light oil were conducted, and all the work was completed on March 25. (NEDO)

FY 1990 report on the results of the development of the entrained bed coal gasification power plant. Part 2. Fabrication/installation of pilot plant; 1990 nendo seika hokokusho. Funryusho sekitan gaska hatsuden plant kaihatsu - Sono 2. Pilot plant seisaku suetsuke hen

Energy Technology Data Exchange (ETDEWEB)

NONE

1991-03-01

For the purpose of establishing the technology of the integrated coal gasification combined cycle power generation, fabrication/installation work, etc. were made for a pilot plant of 200t/d entrained bed coal gasification power generation, and the FY 1990 results were summarized. Construction work of a pilot plant of coal gasification power generation was at its peak in April 1990, and installation/piping work for each facility/equipment was carried out. In May, transportation/installation of gas turbine and generator were started. In June, installation of equipment of the 66kV special high voltage switching station was conducted, and the initial power receiving of 6.9kV was conducted. In August, inspection before use was made of the main piping of the gasifier equipment, gas refining equipment and gas turbine equipment. In December, trial unit operation of each equipment and interlock test were carried out. 'The integrated plant protection interlock test' was made from January 21 to February 21, 1991, and the favorable results were obtained. On February 28, a ceremony to celebrate the completion of all facilities of pilot plant was made. In March, drying of gasifier and initial firing by light oil were conducted, and all the work was completed on March 25. (NEDO)

Development of moving alternating magnetic filter using permanent magnet for removal of radioactive corrosion product from nuclear power plant

International Nuclear Information System (INIS)

Song, M. C.; Kim, S. I.; Lee, K. J.

2002-01-01

Radioactive Corrosion Products (CRUD) which are generated by the neutron activation of general corrosion products at the nuclear power plant are the major source of occupational radiation exposure. Most of the CRUD has a characteristic of showing strong ferrimagnetisms. Along with the new development and production of permanent magnet (rare earth magnet) which generates much stronger magnetic field than the conventional magnet, new type of magnetic filter that can separate CRUD efficiently and eventually reduce radiation exposure of personnel at nuclear power plant is suggested. This separator consists of inner and outer magnet assemblies, coolant channel and container surrounding the outer magnet assembly. The rotational motion of the inner and outer permanent magnet assemblies surrounding the coolant channel by driving motor system produces moving alternating magnetic fields in the coolant channel. The CRUD can be separated from the coolant by the moving alternating magnetic field. This study describes the results of preliminary experiment performed with the different flow rates of coolant and rotation velocities of magnet assemblies. This new magnetic filter shows better performance results of filtering the magnetite at coolant (water). Flow rates, rotating velocities of magnet assemblies and particle sizes turn out to be very important design parameters

Fiscal 1994 achievement report. Development of entrained bed coal gasification power plant (Part 4 - Pilot plant operation); 1994 nendo seika hokokusho. Funryusho sekitan gaska hatsuden plant kaihatsu - Sono 4. Pilot plant unten sosa hen

Energy Technology Data Exchange (ETDEWEB)

NONE

1995-07-01

The 200 tons/day entrained bed coal gasification pilot plant constructed for the establishment of the technology of integrated coal gasification combined cycle power generation was operated for testing, and the results are put together. Operating hours recorded were 1347 hours and 7 minutes for the gasification furnace facility (7 gasification operations), 752 hours and 22 minutes for the gas clean-up facilities, 425 hours and 20 minutes for the gas turbine facility (6 startups for generating 2616.1 MWh), and 1852 hours for the treatment furnace and 1304 hours and 32 minutes for the denitration system in the safety/environment-related facility. Detailed graphs were drawn for the description of starts and stops in Run D8, Run D9 (1-3), Run D10, Run D11, and in Run D12. Operating procedures were studied and then compiled for the plant start-stop schedule, general guidelines, gasification furnace facility, gas clean-up facility (dry type desulfurization facility), gas clean-up facility (dry type dedusting facility), gas turbine facility, real-pressure natural-size combustor test facility, and for the safety/environment related facility. (NEDO)

Use of a moving-bed ion-exchange column for plutonium purification; Utilisation d'une colonne echangeuse d'ions a lit mobile pour la purification du plutonium

Energy Technology Data Exchange (ETDEWEB)

Sabatier, J [Commissariat a l' Energie Atomique, Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires

1965-07-01

When large amounts of fissile matter have to be purified on ion exchange resins, it is difficult to use a fixed bed because of its limiting maximum size. With a moving bed it is possible to ensure a continuous production which can easily be integrated into a purification line on account of its large production capacity. The installation described in this report is derived from an American prototype designed for uranium separation. As a result of many modifications, it is suitable for the purification of plutonium several such columns will shortly be operating in various French centres. The moving bed column, which has a diameter of 25 mm, was first tried with the uranium-thorium mixture; then, after modifications on the plutonium-uranium mixture. The production capacity will depend on the plutonium concentration which can be tolerated in the effluents. It is possible to treat 150 gm/day of plutonium alone; the effluents obtained have a concentration of around of 1 mg/l. The plutonium-uranium separation is improved by a 5 N acidic rinsing as well as by a temperature increase. The decontamination factor increased from 14 in 7 N nitric acid solution to 115 in 5 N nitric acid solution. A temperature increase of about 20 C leads to a decontamination factor of over 500. This result is sufficient encouraging for the possibility of future installations operating in optimum temperature conditions, i.e. 60-65 C, to be considered. (author) [French] Des que l'on desire purifier sur resine echangeuse d'ions des quantites importantes de matieres fissiles, le lit fixe devient difficilement exploitable par suite des dimensions maximum possibles. Le lit mobile permet une production continue pouvant s'integrer facilement par sa capacite de traitement dans une chaine de purification. L'installation decrite dans ce rapport est derivee d'un prototype americain destine a la separation de l'uranium. De nombreuses modifications en font un ensemble utilisable pour la purification du

Bed agglomeration characteristics of palm shell and corncob combustion in fluidized bed

International Nuclear Information System (INIS)

Chaivatamaset, Pawin; Sricharoon, Panchan; Tia, Suvit

2011-01-01

Bed particle agglomeration was studied experimentally in an atmospheric laboratory scale fluidized bed combustor using quartz sand as bed material. Palm shell and corncob were tested. The objectives of the study were (i) to describe the contributions of the biomass ash properties and the operating conditions on the bed agglomeration tendency in term of the bed defluidization time (t def ) and the extent of potassium accumulation in the bed (K/Bed) and (ii) to further elucidate the ash inorganic behaviors and the governing bed agglomeration mechanisms. Defluidization caused by the bed agglomeration was experienced in all experiments during combustion of these biomasses, as a consequence of the presence of potassium in biomass. The experimental results indicated that biomass ash characteristics were the significant influence on the bed agglomeration. The increasing bed temperature, bed particle size and static bed height and the decreasing fluidizing air velocity enhanced the bed agglomeration tendency. The SEM/EDS analyses on the agglomerates confirmed that the agglomeration was attributed to the formation of potassium silicate liquid enriched on the surface of quartz sand particles in conjunction with the high surface temperature of the burning biomass char particles. Thermodynamic examination based on the phase diagram analysis confirmed that the molten phase formation was responsible for the agglomeration. In this study, the high molten ash fraction resulting from the high potassium content in biomass promoted the agglomeration and thus defluidization. - Highlights: → Palm shell and corncob of Thailand are tested their bed agglomeration behaviors during fluidized bed combustion. → The increase of bed temperature, bed particle size and static bed height and the decrease of air velocity enhance bed agglomeration. → The formation of ash derived potassium silicate melts enriched on sand surface is the key process. → The collision between char and sand

The characteristics of bed agglomeration during fluidized bed combustion of eucalyptus bark

International Nuclear Information System (INIS)

Chaivatamaset, Pawin; Tia, Suvit

2015-01-01

The bed agglomeration behaviors were investigated experimentally when eucalyptus bark was burning tested in a laboratory scale fluidized bed reactor. The focuses of this work were the influences of operating conditions and bed materials on the bed agglomeration tendency and the elucidation in the behaviors of fuel inorganic elements and the governing mode of the agglomeration. It was found that the defluidization caused by the bed agglomeration was clearly detectable from the decrease in measured bed pressure. The growth of bed particle and accumulation of agglomerates during combustion provided the partial to complete defluidization. The defluidization was promoted by the increase of bed temperature and bed particle size, and the decrease of fluidizing air velocity. The SEM-EDS analyses revealed that the bed agglomeration was mainly attributed to the formation of potassium silicate compounds as liquid phase during the combustion. This was initiated by the chemical reaction between the bed particle and the released ash constituents. In this study, the inorganic migration from fuel particle to bed particle was likely dominated by the condensation/reaction. The thermodynamic examination by ternary phase diagram analysis corroborated that the liquid phase formation of the ash derived materials controlled the agglomeration. The alumina sand prevented the bed agglomeration since it was inactive in the formation of viscous molten substances during combustion at the observed temperatures. - Highlights: • The behaviors of bed agglomeration were studied during the fluidized bed combustion of eucalyptus bark. • The increase in bed temperature and sand size, and the decrease of air velocity promoted bed defluidization. • The formation of molten potassium silicate compounds conduced to the bed agglomeration. • Condensation/reaction was the dominant inorganic migration mechanism from fuel particle to bed particle. • The alumina sand prevented effectively the bed

Anaerobic Treatment Of Percolate From Faecal Sludge Drying Beds ...

African Journals Online (AJOL)

Composite percolate samples, from sludge drying beds of a pilot co-composting plant in Kumasi, Ghana, were characterised and subjected to laboratory scale anaerobic treatment. Two categories of percolate samples were investigated; samples seeded with anaerobic sludge and samples without seeding. The average ...

Experimental study and large eddy simulation of effect of terrain slope on marginal burning in shrub fuel beds

Science.gov (United States)

Xiangyang Zhou; Shankar Mahalingam; David Weise

2007-01-01

This paper presents a combined study of laboratory scale fire spread experiments and a three-dimensional large eddy simulation (LES) to analyze the effect of terrain slope on marginal burning behavior in live chaparral shrub fuel beds. Line fire was initiated in single species fuel beds of four common chaparral plants under various fuel bed configurations and ambient...

Movements of a Sphere Moving Over Smooth and Rough Inclines

Science.gov (United States)

Jan, Chyan-Deng

1992-01-01

The steady movements of a sphere over a rough incline in air, and over smooth and rough inclines in a liquid were studied theoretically and experimentally. The principle of energy conservation was used to analyze the translation velocities, rolling resistances, and drag coefficients of a sphere moving over the inclines. The rolling resistance to the movement of a sphere from the rough incline was presumed to be caused by collisions and frictional slidings. A varnished wooden board was placed on the bottom of an experimental tilting flume to form a smooth incline and a layer of spheres identical to the sphere moving over them was placed on the smooth wooden board to form a rough incline. Spheres used in the experiments were glass spheres, steel spheres, and golf balls. Experiments show that a sphere moving over a rough incline with negligible fluid drag in air can reach a constant translation velocity. This constant velocity was found to be proportional to the bed inclination (between 11 ^circ and 21^circ) and the square root of the sphere's diameter, but seemingly independent of the sphere's specific gravity. Two empirical coefficients in the theoretical expression of the sphere's translation velocity were determined by experiments. The collision and friction parts of the shear stress exerted on the interface between the moving sphere and rough incline were determined. The ratio of collision to friction parts appears to increase with increase in the bed inclination. These two parts seem to be of the same order of magnitude. The rolling resistances and the relations between the drag coefficient and Reynolds number for a sphere moving over smooth and rough inclines in a liquid, such as water or salad oil, were determined by a regression analysis based on experimental data. It was found that the drag coefficient for a sphere over the rough incline is larger than that for a sphere over the smooth incline, and both of which are much larger than that for a sphere in free

Advanced fluid bed calciner information on IR-100 award

International Nuclear Information System (INIS)

Druby, M.C.; Owen, T.J.; Klem, M.J.

1986-01-01

The advanced fluidized bed calciner provides time, temperature and turbulence to change a liquid slurry such as ammonium diuranate into a uranium dioxide powder. The liquid is sprayed into a hot chamber (up to 700 0 C) which includes thousands of tiny metal beads, about the size of BB's. The constantly moving beads provide an efficient heat transfer media for the immediate transformation of the slurry droplets into dry particles of powder, which are carried out by hot nitrogen gas and recovered in a collector

FY 1989 report on the results of the development of the entrained bed coal gasification power plant. Part 1. Element study; 1989 nendo seika hokokusho. Funryusho sekitan gaska hatsuden plant kaihatsu - Sono 1. Yoso kenkyu hen

Energy Technology Data Exchange (ETDEWEB)

NONE

1990-03-01

For the purpose of establishing the technology of integrated coal gasification combined cycle power generation, element study was conducted of a 200t/d entrained bed coal gasification pilot plant, and the FY 1989 results were summarized. In the gasification test using 2t/d gasifier equipment, the following were carried out: test on gasification of the coal proposed for pilot plant, test on changes in coal feed ratio, analysis of trace gas elements in coal, study of the fixed bed gas refining system, etc. In the study of large gas turbine combustor for demonstration machine, development of combustor which makes stable combustion in the low load region possible, development of low NOx combustor which controls the conversion of nitrogen compounds such as ammonia in coal gasification gas to NOx, development of combustor which makes the optimum and effective cooling possible by combining film cooling, impingement cooling, etc. In the study of simulation of the combined power generation total system, verification tests on the control mode switching function of the general load pressure control system, movement to meet anomaly of the control system, integrated cooperation control system, etc. (NEDO)

Characterization of the pneumatic behavior of a novel spouted bed apparatus with two adjustable gas inlets

NARCIS (Netherlands)

Gryczka, O.; Heinrich, S.; Miteva, V.; Deen, N.G.; Kuipers, J.A.M.; Jacob, M.; Morl, L.

2008-01-01

Recently the importance of spouted bed technology has significantly increased in the context of drying processes as well as granulation, agglomeration or coating processes. Within this work the fluid dynamics of a novel spouted bed plant with two adjustable gas inlets is investigated. By analysis of

Improved methods for irrigation and planting of major crops in waterlogged areas

International Nuclear Information System (INIS)

Kahlown, M.A.; Iqbal, M.; Raoof, A.

2002-01-01

The improved irrigation methods for wheat and cotton were evaluated in the fordwah Eastern Sadigia (South) Irrigation and Drainage Project area, during 1996-97 and 1997-98 cropping seasons, under three water table depths. Irrigation methods for wheat included 70, 95 and 120 cm Beds, with Flat Basin, as a check for comparative evaluation. Cotton had Ridge-planting on the top and side, Bed and Furrow, and Flat Basin as control. These irrigation methods were compared at water table depths of < 1 m, 1-2 and 2-3 m. The wheat variety inqalab-91, and cotton cultivar, CIM-109, were planted during the 3rd week of November and May every year. All the inputs and management practices, such as seed-rate, fertilizer, seeding method, weed control, plant-protection measures, etc. were kept common. The results on cotton indicated maximum water-use efficiency with the Bed and Furrow Method of irrigation Followed by ridge planting. The traditional Flat-planting had the lowest yield and the highest water-consumption, resulting in the minimum water-use efficiency. In harmony with cotton, the Flat Method of planting had maximum water-consumption. For wheat crop, the water-use efficiency was in descending order, with 120, 95 and 70 cm for Bed and Flat Methods. Bed planting of 95 cm had a fairly high water-use efficiency and yields were more were more comparable than Flat planting. This method had a high level of adaptabilities, especially when the groundwater was close to the root-zone and higher possibilities, especially when the groundwater was close to the root-zone and higher possibility of crop-submergence are existent during rainy spells. The results of the investigation strongly favoured the Bed and furrow methods to irrigate cotton and wheat. However, under well-drained soil conditions, Bed planting of wheat is not recommended. (author)

Achievement report for fiscal 1993 on developing entrained bed coal gasification power plant. Part 4. Pilot plant operation edition; 1993 nendo seika hokokusho. Funryusho sekitan gaska hatsuden plant kaihatsu - Sono 4. Pilot plant unten sosa hen

Energy Technology Data Exchange (ETDEWEB)

NONE

1995-02-01

Tests and researches have been carried out on operation of a 200-t/d entrained bed coal gasification pilot plant built with an objective of establishing the coal gasification composite power generation technology. This paper summarizes the operation achievements in fiscal 1993. The plant operation record in fiscal 1993 was as follows: 430 hours 27 minutes in the gasification furnace (ten gasification operations), 233 hours 51 minutes in the gas refining facility, 140 hours 31 minutes in the gas turbine facility (power generation amount of 746.8 MWh with nine actuations), 1,263 hours 09 minutes in the processing furnace in the safety environment facility, and 427 hours 22 minutes in the NOx removal equipment. Descriptions were given with detailed graphs on the actuation and shutdown record with respect to the run D2, the run D3 (1 and 2), the run D4, the run D5, the run D6, and the run D7 (1 through 4). The operation procedures were prepared for the plant startup and shutdown schedule, the generalization report, the gasification furnace facility, the gas refining facility (dry type desulfurizing facility), the gas refining facility (dry type dust removing facility), the gas turbine facility, the combustor testing facility with actual pressure and size, and the safety environment facilities. (NEDO)

Mathematical modelling of sewage sludge incineration in a bubbling fluidised bed with special consideration for thermally-thick fuel particles.

Science.gov (United States)

Yang, Yao Bin; Sharifi, Vida; Swithenbank, Jim

2008-11-01

Fluidised bed combustor (FBC) is one of the key technologies for sewage sludge incineration. In this paper, a mathematical model is developed for the simulation of a large-scale sewage sludge incineration plant. The model assumes the bed consisting of a fast-gas phase, an emulsion phase and a fuel particle phase with specific consideration for thermally-thick fuel particles. The model further improves over previous works by taking into account throughflow inside the bubbles as well as the floating and random movement of the fuel particles inside the bed. Validation against both previous lab-scale experiments and operational data of a large-scale industrial plant was made. Calculation results indicate that combustion split between the bed and the freeboard can range from 60/40 to 90/10 depending on the fuel particle distribution across the bed height under the specific conditions. The bed performance is heavily affected by the variation in sludge moisture level. The response time to variation in feeding rate is different for different parameters, from 6 min for outlet H2O, 10 min for O2, to 34 min for bed temperature.

Production of renewable energy from biomass and waste materials using fluidized bed technologies

International Nuclear Information System (INIS)

Rozainee, M.; Rashid, M.; Looi, S.

2000-01-01

Malaysian industries generate substantial amount of biomass and waste materials such as wastes from agricultural and wood based industries, sludge waste from waste-water treatment plants and solid waste from municipals. Incinerating these waste materials not only produces renewable energy, but also solving their disposal problems. Fluidized bed combustors are widely used for incinerating these biomass materials. The significant advantages of fluidized bed incineration include simple design, efficient, and ability to reduce air pollution emissions. This paper discusses the opportunities and challenges of producing the green energy from biomass materials using the fluidized bed technologies. (Author)

Study for Safeguards Challenges to the Most Probably First Indonesian Future Power Plant of the Pebble Bed Modular Reactor

International Nuclear Information System (INIS)

Susilowati, E.

2015-01-01

In the near future Indonesia, the fourth most populous country, plans to build a small size power plant most probably a Pebble Bed Modular Reactor PBMR. This first nuclear power plant (NPP) is aimed to provide clear picture to the society in regard to performance and safety of nuclear power plant operation. Selection to the PBMR based on several factor including the combination of small size of the reactor and type of fuel allowing the use of passive safety systems, resulting in essential advantages in nuclear plant design and less dependence on plant operators for safety. In the light of safeguards perspective this typical reactor is also quite difference with previous light water reactor (LWR) design. From the fact that there are a small size large number of elements present in the reactor produced without individual serial numbers combine to on-line refueling same as the CANDU reactor, enforcing a new challenge to safeguards approach for this typical reactor. This paper discusses a bunch of safeguards measures have to be prepared by facility operator to support successfully international nuclear material and facility verification including elements of design relevant to safeguards need to be accomplished in consultation to the regulatory body, supplier or designer and the Agency/IAEA such as nuclear material balance area and key measurement point; possible diversion scenarios and safeguards strategy; and design features relevant to the IAEA equipment have to be installed at the reactor facility. It is deemed that result of discussion will alleviate and support the Agency approaching safeguards measure that may be applied to the purpose Indonesian first power plant of PBMR construction and operation. (author)

7 CFR 2902.15 - Bedding, bed linens, and towels.

Science.gov (United States)

2010-01-01

... PROCUREMENT Designated Items § 2902.15 Bedding, bed linens, and towels. (a) Definition. (1) Bedding is that... minimum biobased content is 12 percent and shall be based on the amount of qualifying biobased carbon in..., and silk are not qualifying biobased feedstocks for the purpose of determining the biobased content of...

DEVELOPMENT OF PRESSURIZED CIRCULATING FLUIDIZED BED PARTIAL GASIFICATION MODULE (PGM)

International Nuclear Information System (INIS)

Unknown

2001-01-01

Foster Wheeler Development Corporation is working under DOE contract No. DE-FC26-00NT40972 to develop a partial gasification module (PGM) that represents a critical element of several potential coal-fired Vision 21 plants. When utilized for electrical power generation, these plants will operate with efficiencies greater than 60% while producing near zero emissions of traditional stack gas pollutants. The new process partially gasifies coal at elevated pressure producing a coal-derived syngas and a char residue. The syngas can be used to fuel the most advanced power producing equipment such as solid oxide fuel cells or gas turbines or processed to produce clean liquid fuels or chemicals for industrial users. The char residue is not wasted; it can also be used to generate electricity by fueling boilers that drive the most advanced ultra-supercritical pressure steam turbines. The unique aspect of the process is that it utilizes a pressurized circulating fluidized bed partial gasifier and does not attempt to consume the coal in a single step. To convert all the coal to syngas in a single step requires extremely high temperatures ((approx)2500 to 2800F) that melt and vaporize the coal and essentially drive all coal ash contaminants into the syngas. Since these contaminants can be corrosive to power generating equipment, the syngas must be cooled to near room temperature to enable a series of chemical processes to clean the syngas. Foster Wheeler's process operates at much lower temperatures that control/minimize the release of contaminants; this eliminates/minimizes the need for the expensive, complicated syngas heat exchangers and chemical cleanup systems typical of high temperature gasification. By performing the gasification in a circulating bed, a significant amount of syngas can still be produced despite the reduced temperature and the circulating bed allows easy scale up to large size plants. Rather than air, it can also operate with oxygen to facilitate

Evaluation of a clay-based acidic bedding conditioner for dairy cattle bedding.

Science.gov (United States)

Proietto, R L; Hinckley, L S; Fox, L K; Andrew, S M

2013-02-01

This study investigated the effects of a clay-based acidic bedding conditioner on sawdust bedding pH, dry matter (DM), environmental pathogen counts, and environmental bacterial counts on teat ends of lactating dairy cows. Sixteen lactating Holstein cows were paired based on parity, days in milk, milk yield, and milk somatic cell count, and were negative for the presence of an intramammary pathogen. Within each pair, cows were randomly assigned to 1 of 2 treatments with 3-wk periods in a crossover design. Treatment groups consisted of 9 freestalls per group bedded with either untreated sawdust or sawdust with a clay-based acidic bedding conditioner, added at 3- to 4-d intervals over each 21-d period. Bedding and teat ends were aseptically sampled on d 0, 1, 2, 7, 14, and 21 for determination of environmental bacterial counts. At the same time points, bedding was sampled for DM and pH determination. The bacteria identified in the bedding material were total gram-negative bacteria, Streptococcus spp., and coliform bacteria. The bacteria identified on the teat ends were Streptococcus spp., coliform bacteria, and Klebsiella spp. Teat end score, milk somatic cell count, and intramammary pathogen presence were measured weekly. Bedding and teat cleanliness, environmental high and low temperatures, and dew point data were collected daily. The bedding conditioner reduced the pH, but not the DM, of the sawdust bedding compared with untreated sawdust. Overall environmental bacterial counts in bedding were lower for treated sawdust. Total bacterial counts in bedding and on teat ends increased with time over both periods. Compared with untreated sawdust, the treated bedding had lower counts of total gram-negative bacteria and streptococci, but not coliform counts. Teat end bacterial counts were lower for cows bedded on treated sawdust for streptococci, coliforms, and Klebsiella spp. compared with cows bedded on untreated sawdust. The clay-based acidic bedding conditioner

Test bed for applications of heterogeneous unmanned vehicles

Directory of Open Access Journals (Sweden)

Filiberto Muñoz Palacios

2017-01-01

Full Text Available This article addresses the development and implementation of a test bed for applications of heterogeneous unmanned vehicle systems. The test bed consists of unmanned aerial vehicles (Parrot AR.Drones versions 1 or 2, Parrot SA, Paris, France, and Bebop Drones 1.0 and 2.0, Parrot SA, Paris, France, ground vehicles (WowWee Rovio, WowWee Group Limited, Hong Kong, China, and the motion capture systems VICON and OptiTrack. Such test bed allows the user to choose between two different options of development environments, to perform aerial and ground vehicles applications. On the one hand, it is possible to select an environment based on the VICON system and LabVIEW (National Instruments or robotics operating system platforms, which make use the Parrot AR.Drone software development kit or the Bebop_autonomy Driver to communicate with the unmanned vehicles. On the other hand, it is possible to employ a platform that uses the OptiTrack system and that allows users to develop their own applications, replacing AR.Drone’s original firmware with original code. We have developed four experimental setups to illustrate the use of the Parrot software development kit, the Bebop Driver (AutonomyLab, Simon Fraser University, British Columbia, Canada, and the original firmware replacement for performing a strategy that involves both ground and aerial vehicle tracking. Finally, in order to illustrate the effectiveness of the developed test bed for the implementation of advanced controllers, we present experimental results of the implementation of three consensus algorithms: static, adaptive, and neural network, in order to accomplish that a team of multiagents systems move together to track a target.

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.

Middle Stone Age bedding construction and settlement patterns at Sibudu, South Africa.

Science.gov (United States)

Wadley, Lyn; Sievers, Christine; Bamford, Marion; Goldberg, Paul; Berna, Francesco; Miller, Christopher

2011-12-09

The Middle Stone Age (MSA) is associated with early behavioral innovations, expansions of modern humans within and out of Africa, and occasional population bottlenecks. Several innovations in the MSA are seen in an archaeological sequence in the rock shelter Sibudu (South Africa). At ~77,000 years ago, people constructed plant bedding from sedges and other monocotyledons topped with aromatic leaves containing insecticidal and larvicidal chemicals. Beginning at ~73,000 years ago, bedding was burned, presumably for site maintenance. By ~58,000 years ago, bedding construction, burning, and other forms of site use and maintenance intensified, suggesting that settlement strategies changed. Behavioral differences between ~77,000 and 58,000 years ago may coincide with population fluctuations in Africa.

Fluid bed dryer and Aeropep solidification system. Amendment 1 to topical report

International Nuclear Information System (INIS)

1975-01-01

Information is presented on interfaces between the aerojet fluid bed dryer and the liquid radwaste system, plant ventilation system, and radioactive solid waste handling system for BWR and PWR type reactors. (U.S.)

Fixed bed gasification of solid biomass fuels

Energy Technology Data Exchange (ETDEWEB)

Haavisto, I [Condens Oy, Haemeenlinna (Finland)

1997-12-31

Fixed bed biomass gasifiers are feasible in the effect range of 100 kW -10 MW. Co-current gasification is available only up to 1 MW for technical reasons. Counter-current gasifiers have been used in Finland and Sweden for 10 years in gasification heating plants, which are a combination of a gasifier and an oil boiler. The plants have proved to have a wide control range, flexible and uncomplicated unmanned operation and an excellent reliability. Counter-current gasifiers can be applied for new heating plants or for converting existing oil and natural gas boilers into using solid fuels. There is a new process development underway, aiming at motor use of the producer gas. The development work involves a new, more flexible cocurrent gasifier and a cleaning step for the counter-current producer gas. (orig.)

Fixed bed gasification of solid biomass fuels

Energy Technology Data Exchange (ETDEWEB)

Haavisto, I. [Condens Oy, Haemeenlinna (Finland)

1996-12-31

Fixed bed biomass gasifiers are feasible in the effect range of 100 kW -10 MW. Co-current gasification is available only up to 1 MW for technical reasons. Counter-current gasifiers have been used in Finland and Sweden for 10 years in gasification heating plants, which are a combination of a gasifier and an oil boiler. The plants have proved to have a wide control range, flexible and uncomplicated unmanned operation and an excellent reliability. Counter-current gasifiers can be applied for new heating plants or for converting existing oil and natural gas boilers into using solid fuels. There is a new process development underway, aiming at motor use of the producer gas. The development work involves a new, more flexible cocurrent gasifier and a cleaning step for the counter-current producer gas. (orig.)

FY 1991 report on the results of the development of an entrained bed coal gasification power plant. Part 1. Support study for the development of an entrained bed coal gasification power plant (Dismantling study); 1991 nendo seika hokokusho. Funryusho sekitan gaska hatsuden plant kaihatsu (Funryusho sekitan gaska hatsuden plant kaihatsu no shien kenkyu) - Sono 1. Kaitai kenkyu hen

Energy Technology Data Exchange (ETDEWEB)

NONE

1992-04-01

As a support study for the development of an entrained bed coal gasification power plant by a 200 t/d pilot plant, the dismantling study was made for gasifier facilities, desulfurization facilities, dedusting facilities at the existing 40 t/d testing facilities. In the results of the analysis of the specimens sampled from gasifier and peripheral facilities, the corrosion loss of thickness was great in carbon steel/low-alloy steel equipment, and the generation of intergranular corrosion/intergranular crack was recognized in stainless steel equipment. The loss of thickness caused by erosion was also recognized in carrier tubes, etc. As to the high-temperature dry desulfurization system, the damage was totally great, but the effect of taking measures for it was unclear because the loss of thickness by corrosion/abrasion had not been measured regularly. Relating to the high-temperature dry dedusting system, there used to be a lot of troubles from stress corrosion cracking and pitting corrosion, and the best measures for corrosion prevention were taken for each trouble. As to the Al thermal spraying, stabilized thermal treatment, shot-peening, etc., the excellent corrosion prevention effect was recognized on the austenite stainless steel. (NEDO)

The thermal denigration in fluid-bed to make uranyl product

International Nuclear Information System (INIS)

Ma Zhenrong; Cui Yulin; Zhu Changbing; Fan Chuanyong; Liu Yanfeng

2010-01-01

Nuclear fuel reprocessing plant used the thermal denigration to high concentration of uranyl nitrate solution in fluid-bed to make uranyl product. First the uranyl nitrate solution were concentrated in evaporator, into 300 gU/L, 600 gU/L, 750 gU/L and 1000 gU/L.When the fluid-bed was in good fluidity state at 320 degree C, the solution was sprayed all over the surface of the fine crystal seeds through the dual-channel air-blast nozzles to make new crystal seed and to make them grow up. The denigration reaction occurred when the internal temperature of the fluid-bed was kept at about 300 degree C by the outside and inside heat apparatus. The product were transported crossing the valve and spiral transfer to pack. The tail gas was purified and discharged. Through the fluid-bed's running, the variation discipline of temperature and the pressure, the effect curve of the quality of product accumulated to pressure drop were determined. At the same time, the gentrification temperature, the distributed heat and the transfer mode were tested. (authors)

Determination of the external mass transfer coefficient and influence of mixing intensity in moving bed biofilm reactors for wastewater treatment.

Science.gov (United States)

Nogueira, Bruno L; Pérez, Julio; van Loosdrecht, Mark C M; Secchi, Argimiro R; Dezotti, Márcia; Biscaia, Evaristo C

2015-09-01

In moving bed biofilm reactors (MBBR), the removal of pollutants from wastewater is due to the substrate consumption by bacteria attached on suspended carriers. As a biofilm process, the substrates are transported from the bulk phase to the biofilm passing through a mass transfer resistance layer. This study proposes a methodology to determine the external mass transfer coefficient and identify the influence of the mixing intensity on the conversion process in-situ in MBBR systems. The method allows the determination of the external mass transfer coefficient in the reactor, which is a major advantage when compared to the previous methods that require mimicking hydrodynamics of the reactor in a flow chamber or in a separate vessel. The proposed methodology was evaluated in an aerobic lab-scale system operating with COD removal and nitrification. The impact of the mixing intensity on the conversion rates for ammonium and COD was tested individually. When comparing the effect of mixing intensity on the removal rates of COD and ammonium, a higher apparent external mass transfer resistance was found for ammonium. For the used aeration intensities, the external mass transfer coefficient for ammonium oxidation was ranging from 0.68 to 13.50 m d(-1) and for COD removal 2.9 to 22.4 m d(-1). The lower coefficient range for ammonium oxidation is likely related to the location of nitrifiers deeper in the biofilm. The measurement of external mass transfer rates in MBBR will help in better design and evaluation of MBBR system-based technologies. Copyright © 2015 Elsevier Ltd. All rights reserved.

Fluidised bed cereal cooking

International Nuclear Information System (INIS)

Jenkins, Simon Anthony

2002-01-01

Man has been cooking food for thousands of years for a number of reasons: to improve flavour and palatability, sterilise, increase digestibility, improve texture and colour. Increasingly more advanced techniques are employed today in food production plants to engineer foods with many different properties. With this in mind manufacturers are constantly seeking to improve processing techniques and apply new or different technologies (such as microwaves, RF and extrusion) to develop foods with new properties (like puffed texture starches) and to increase process efficiencies (energy efficiency, water reduction). This thesis reports on work undertaken to demonstrate the potential to achieve high temperature starch conversion of whole wheat grains in a fluidised bed, thereby reducing the amount of water required and processing time. Specifically, wheat from the farm at 14% water content is cooked in a fluidised bed. The fluidised bed heats the wheat quickly by convective heating. In addition, energy can be delivered directly to the grain by microwave heating during fluidisation. Degree of starch conversion is determined by measuring the reduction in size of endotherm of reaction as observed by Differential Scanning Calorimetry. The fluidising gas, processing temperature and starting moisture content were varied in order to investigate their effect on the cooking process. A mathematical model based on energy and species concentration equations was developed to help understand the internal grain processes. The model coupled the thermal energy equation with water diffusion. The effect of water evaporation was represented as a thermal sink in the energy equation. Popular kinetic models from literature were adapted to predict the degree of starch conversion. The model gives solutions consistent with experimental data and physical intuition. A commercial computational fluid dynamics package was used to study simple airflow and particle tracks in the fluidisation column. A

Analysis of todays best available technology for biomass fired heating plants in the interval 0.5 to 10 MW

International Nuclear Information System (INIS)

Karlsson, Mats-Lennart; Gustavsson, Lennart; Maartensson, D.; Leckner, B.

1998-01-01

The purpose of the present project has been to study today's best available technology for biomass fired heating plants in the interval 0.5 to 10 MW from an emission point of view. Emission measurements have been conducted at 21 plants of different types and sizes, i.e. one stationary fluidized bed, fourteen boilers with moving grates, four boilers with fixed grates, one pellet burner and one boiler with a gasification oven. The plants were fired with different fuels: native fuels like wood chips, bark/sawdust, grass and refined fuels like briquettes and pellets. The plants were chosen to represent the best available and/or the most common technology. The flue gases were analyzed for CO, NO x , Total Hydrocarbons (THC), methane, ethylene, acetylene, ammonia, nitrous oxide, CO 2 and O 2 . The measurements were usually made at the heat loads and operating conditions given at the time of testing. However, in a few cases measurements were made at different loads and air settings

Endocrine active chemicals, pharmaceuticals, and other chemicals of concern in surface water, wastewater-treatment plant effluent, and bed sediment, and biological characteristics in selected streams, Minnesota-design, methods, and data, 2009

Science.gov (United States)

Lee, Kathy E.; Langer, Susan K.; Barber, Larry B.; Writer, Jeff H.; Ferrey, Mark L.; Schoenfuss, Heiko L.; Furlong, Edward T.; Foreman, William T.; Gray, James L.; ReVello, Rhiannon C.; Martinovic, Dalma; Woodruff, Olivia R.; Keefe, Steffanie H.; Brown, Greg K.; Taylor, Howard E.; Ferrer, Imma; Thurman, E. Michael

2011-01-01

This report presents the study design, environmental data, and quality-assurance data for an integrated chemical and biological study of selected streams or lakes that receive wastewater-treatment plant effluent in Minnesota. This study was a cooperative effort of the U.S. Geological Survey, the Minnesota Pollution Control Agency, St. Cloud State University, the University of St. Thomas, and the University of Colorado. The objective of the study was to identify distribution patterns of endocrine active chemicals, pharmaceuticals, and other organic and inorganic chemicals of concern indicative of wastewater effluent, and to identify biological characteristics of estrogenicity and fish responses in the same streams. The U.S. Geological Survey collected and analyzed water, bed-sediment, and quality-assurance samples, and measured or recorded streamflow once at each sampling location from September through November 2009. Sampling locations included surface water and wastewater-treatment plant effluent. Twenty-five wastewater-treatment plants were selected to include continuous flow and periodic release facilities with differing processing steps (activated sludge or trickling filters) and plant design flows ranging from 0.002 to 10.9 cubic meters per second (0.04 to 251 million gallons per day) throughout Minnesota in varying land-use settings. Water samples were collected from the treated effluent of the 25 wastewater-treatment plants and at one point upstream from and one point downstream from wastewater-treatment plant effluent discharges. Bed-sediment samples also were collected at each of the stream or lake locations. Water samples were analyzed for major ions, nutrients, trace elements, pharmaceuticals, phytoestrogens and pharmaceuticals, alkylphenols and other neutral organic chemicals, carboxylic acids, and steroidal hormones. A subset (25 samples) of the bed-sediment samples were analyzed for carbon, wastewater-indicator chemicals, and steroidal hormones; the

Microwave-assisted synthesis of geopolymers from fluidised bed gasifier bottom ash

CSIR Research Space (South Africa)

Oboirien, BO

2013-09-01

Full Text Available Fluidised bed gasification (FBG) is a clean coal technology suitable for power and fuel generation from low grade coals. However, the resulting bottom ash presents some disposal challenges to the power plants and the environment. The production...

Chemical-looping combustion in a reverse-flow fixed bed reactor

International Nuclear Information System (INIS)

Han, Lu; Bollas, George M.

2016-01-01

A reverse-flow fixed bed reactor concept for CLC (chemical-looping combustion) is explored. The limitations of conventional fixed bed reactors, as applied to CLC, are overcome by reversing the gas flow direction periodically to enhance the mixing characteristics of the bed, thus improving oxygen carrier utilization and energy efficiency with respect to power generation. The reverse-flow reactor is simulated by a dusty-gas model and compared with an equivalent fixed bed reactor without flow reversal. Dynamic optimization is used to calculate conditions at which each reactor operates at maximum energy efficiency. Several cases studies illustrate the benefits of reverse-flow operation for the CLC with CuO and NiO oxygen carriers and methane and syngas fuels. The results show that periodic reversal of the flow during reduction improves the contact between the fuel and unconverted oxygen carrier, enabling the system to suppress unwanted catalytic reactions and axial temperature and conversion gradients. The operational scheme presented reduces the fluctuations of temperature during oxidation and increases the high-temperature heat produced by the process. CLC in a reverse-flow reactor has the potential to achieve higher energy efficiency than conventional fixed bed CLC reactors, when integrated with a downstream gas turbine of a combined cycle power plant. - Highlights: • Reverse-flow fixed bed CLC reactors for combined cycle power systems. • Dynamic optimization tunes operation of batch and transient CLC systems. • The reverse-flow CLC system provides stable turbine-ready gas stream. • Reverse-flow CLC fixed bed reactor has superior CO 2 capture and thermal efficiency.

The underlying reasons for very high levels of bed net use, and higher malaria infection prevalence among bed net users than non-users in the Tanzanian city of Dar es Salaam: a qualitative study.

Science.gov (United States)

Msellemu, Daniel; Shemdoe, Aloysia; Makungu, Christina; Mlacha, Yeromini; Kannady, Khadija; Dongus, Stefan; Killeen, Gerry F; Dillip, Angel

2017-10-23

Bed nets reduce malaria-related illness and deaths, by forming a protective barrier around people sleeping under them. When impregnated with long-lasting insecticide formulations they also repel or kill mosquitoes attempting to feed upon sleeping humans, and can even suppress entire populations of malaria vectors that feed predominantly upon humans. Nevertheless, an epidemiological study in 2012 demonstrated higher malaria prevalence among bed net users than non-users in urban Dar es Salaam, Tanzania. Focus group discussions were conducted with women from four selected wards of Dar es Salaam city, focusing on four major themes relating to bed net use behaviours: (1) reasons for bed net use, (2) reasons for not using bed nets, (3) stimuli or reminders for people to use a bed net (4) perceived reasons for catching malaria while using a bed net. An analytical method by framework grouping of relevant themes was used address key issues of relevance to the study objectives. Codes were reviewed and grouped into categories and themes. All groups said the main reason for bed net use was protection against malaria. Houses with well-screened windows, with doors that shut properly, and that use insecticidal sprays against mosquitoes, were said not to use bed nets, while frequent attacks from malaria was the main stimulus for people to use bed nets. Various reasons were mentioned as potential reasons that compromise bed net efficacy, the most common of which were: (1) bed net sharing by two or more people, especially if one occupant tends to come to bed late at night, and does not tuck in the net 71%; (2) one person shares the bed but does not use the net, moving it away from the side on which s/he sleeps 68%; (3) ineffective usage habits, called ulalavi, in which a sprawling sleeper either touches the net while sleeping up against it or leaves a limb hanging outside of it 68%. Less common reasons mentioned included: (1) Small bed nets which become un-tucked at night (31%); (2

Fluidized bed incineration of radioactive waste

International Nuclear Information System (INIS)

Ziegler, D.L.

1976-01-01

A fluidized-bed incineration facility is being designed for installation at the Rocky Flats Plant to demonstrate a process for the combustion of transuranic waste. The unit capacity will be about 82 kg/hr of combustible waste. The combustion process will utilize in situ neutralization of acid gases generated in the process. The equipment design is based on data generated on a pilot unit and represents a scale-up of nine. Title I engineering is at least 70 percent complete

Technical and economic assessment of fluidized bed augmented compressed air energy storage system. Volume III. Preconceptual design

Energy Technology Data Exchange (ETDEWEB)

Giramonti, A.J.; Lessard, R.D.; Merrick, D.; Hobson, M.J.

1981-09-01

A technical and economic assessment of fluidized bed combustion augmented compressed air energy storage systems is presented. The results of this assessment effort are presented in three volumes. Volume III - Preconceptual Design contains the system analysis which led to the identification of a preferred component configuration for a fluidized bed combustion augmented compressed air energy storage system, the results of the effort which transformed the preferred configuration into preconceptual power plant design, and an introductory evaluation of the performance of the power plant system during part-load operation and while load following.

Coolability of oxidized particulate debris bed accumulated in horizontal narrow gaps

International Nuclear Information System (INIS)

Arai, Y.; Sugiyama, K.; Narabayashi, T.

2007-01-01

When LOCA occurs in a nuclear reactor system, the coolability of the core would be kept as reported at a series of presentations in ICONE14. Therefore the probability of the core meltdown is negligible small. However, from the view point of defense in depth, it is necessary to be sure that the coolability of the bottom of reactor pressure vessel (RPV) is maintained even if a part of the core should melt and a substantial amount of debris should be deposited on the lower plenum. We carried out an experimental study in order to observe the coolability of particulate core-metal debris bed with 12 mm thickness accompanied with rapid heat generation because of oxidization, which was reported at ICONE14. The coolability was assured by a small amount of coolant supply because of high capillary force of oxidized fine particulate debris produced. In the present study, we examined the coolability of particulate debris bed deposited in narrower gap of 1 mm or 5 mm that coolant supply is hard. The particulate debris beds were piled up on the stainless steel sheet with 0.1 mm thickness, which was used to measure the bottom temperatures of particulate debris bed by using a thermo-video camera. We set up a heat supply section with heat input of 2.1 kW, which simulates the hard debris bed deposited on the particulate debris bed as reported for the TMI-2 accident. We measured the temperatures of the bottom surface of the heat supply section and the heat fluxes released into debris bed as well as the temperatures at the bottom of debris bed on the stainless steel sheet. It is found that when only the upper surface of particulate debris bed is in the film boiling, capillary force causes coolant supply to the particulate debris bed. Therefore, in the condition of thicker gap with small particulate debris, coolability of debris bed is improved. We find out that smaller particulate debris is moved by vapor movement. As a result, the area that high capillary force is caused because of

Automation and control in industrial installations. Its application in pressurized fluidized bed plants, coal washeries etc. Automatizacion y control en instalaciones industriales. Su aplicacion en centrales de lecho fluido a presion, lavaderos de carbon etc

Energy Technology Data Exchange (ETDEWEB)

Trujillo Tarifa, R. (ENDESA, Madrid (Spain))

1988-01-01

This paper presents the automation and electronic control systems, based on the most advanced technologies on the market. The most recent techniques concerning industrial plant supervision and the processing of information obtained from the above mentioned systems are discussed. Intraplant communications between the control systems and the supervision computers as well as communications among cascade computers are described. These studies are applied to specific cases of pressurized fluidized bed plants, coal washing plants, coal yards, etc.

Prostate Bed Motion During Intensity-Modulated Radiotherapy Treatment

International Nuclear Information System (INIS)

Klayton, Tracy; Price, Robert; Buyyounouski, Mark K.; Sobczak, Mark; Greenberg, Richard; Li, Jinsheng; Keller, Lanea; Sopka, Dennis; Kutikov, Alexander; Horwitz, Eric M.

2012-01-01

Purpose: Conformal radiation therapy in the postprostatectomy setting requires accurate setup and localization of the prostatic fossa. In this series, we report prostate bed localization and motion characteristics, using data collected from implanted radiofrequency transponders. Methods and Materials: The Calypso four-dimensional localization system uses three implanted radiofrequency transponders for daily target localization and real-time tracking throughout a course of radiation therapy. We reviewed the localization and tracking reports for 20 patients who received ultrasonography-guided placement of Calypso transponders within the prostate bed prior to a course of intensity-modulated radiation therapy at Fox Chase Cancer Center. Results: At localization, prostate bed displacement relative to bony anatomy exceeded 5 mm in 9% of fractions in the anterior-posterior (A-P) direction and 21% of fractions in the superior-inferior (S-I) direction. The three-dimensional vector length from skin marks to Calypso alignment exceeded 1 cm in 24% of all 652 fractions with available setup data. During treatment, the target exceeded the 5-mm tracking limit for at least 30 sec in 11% of all fractions, generally in the A-P or S-I direction. In the A-P direction, target motion was twice as likely to move posteriorly, toward the rectum, than anteriorly. Fifteen percent of all treatments were interrupted for repositioning, and 70% of patients were repositioned at least once during their treatment course. Conclusion: Set-up errors and motion of the prostatic fossa during radiotherapy are nontrivial, leading to potential undertreatment of target and excess normal tissue toxicity if not taken into account during treatment planning. Localization and real-time tracking of the prostate bed via implanted Calypso transponders can be used to improve the accuracy of plan delivery.

Implementation of a RPS Cyber Security Test-bed with Two PLCs

International Nuclear Information System (INIS)

Shin, Jinsoo; Heo, Gyunyoung; Son, Hanseong; An, Yongkyu; Rizwan, Uddin

2015-01-01

Our research team proposed the methodology to evaluate cyber security with Bayesian network (BN) as a cyber security evaluation model and help operator, licensee, licensor or regulator in granting evaluation priorities. The methodology allowed for overall evaluation of cyber security by considering architectural aspect of facility and management aspect of cyber security at the same time. In order to emphasize reality of this model by inserting true data, it is necessary to conduct a penetration test that pretends an actual cyber-attack. Through the collaboration with University of Illinois at Urbana-Champaign, which possesses the Tricon a safety programmable logic controller (PLC) used at nuclear power plants and develops a test-bed for nuclear power plant, a test-bed for reactor protection system (RPS) is being developed with the PLCs. Two PLCs are used to construct a simple test-bed for RPS, bi-stable processor (BP) and coincidence processor (CP). By using two PLCs, it is possible to examine cyber-attack against devices such as PLC, cyber-attack against communication between devices, and the effects of a PLC on the other PLC. Two PLCs were used to construct a test-bed for penetration test in this study. Advantages of using two or more PLCs instead of single PLC are as follows. 1) Results of cyber-attack reflecting characteristics among PLCs can be obtained. 2) Cyber-attack can be attempted using a method of attacking communication between PLCs. True data obtained can be applied to existing cyber security evaluation model to emphasize reality of the model

Implementation of a RPS Cyber Security Test-bed with Two PLCs

Energy Technology Data Exchange (ETDEWEB)

Shin, Jinsoo; Heo, Gyunyoung [Kyung Hee Univ., Yongin (Korea, Republic of); Son, Hanseong [Joongbu Univ., Geumsan (Korea, Republic of); An, Yongkyu; Rizwan, Uddin [University of Illinois at Urbana-Champaign, Urbana (United States)

2015-10-15

Our research team proposed the methodology to evaluate cyber security with Bayesian network (BN) as a cyber security evaluation model and help operator, licensee, licensor or regulator in granting evaluation priorities. The methodology allowed for overall evaluation of cyber security by considering architectural aspect of facility and management aspect of cyber security at the same time. In order to emphasize reality of this model by inserting true data, it is necessary to conduct a penetration test that pretends an actual cyber-attack. Through the collaboration with University of Illinois at Urbana-Champaign, which possesses the Tricon a safety programmable logic controller (PLC) used at nuclear power plants and develops a test-bed for nuclear power plant, a test-bed for reactor protection system (RPS) is being developed with the PLCs. Two PLCs are used to construct a simple test-bed for RPS, bi-stable processor (BP) and coincidence processor (CP). By using two PLCs, it is possible to examine cyber-attack against devices such as PLC, cyber-attack against communication between devices, and the effects of a PLC on the other PLC. Two PLCs were used to construct a test-bed for penetration test in this study. Advantages of using two or more PLCs instead of single PLC are as follows. 1) Results of cyber-attack reflecting characteristics among PLCs can be obtained. 2) Cyber-attack can be attempted using a method of attacking communication between PLCs. True data obtained can be applied to existing cyber security evaluation model to emphasize reality of the model.

Proposed chemical plant initiated accident scenarios in a sulphur-iodine cycle plant coupled to a pebble bed modular reactor

International Nuclear Information System (INIS)

Brown, N.R.; Revankar, S.T.; Seker, V.; Downar, Th.J.

2010-01-01

In the sulphur-iodine (S-I) cycle nuclear hydrogen generation scheme the chemical plant acts as the heat sink for the very high temperature nuclear reactor (VHTR). Thus, any accident which occurs in the chemical plant must feedback to the nuclear reactor. There are many different types of accidents which can occur in a chemical plant. These accidents include intra-reactor piping failure, inter-reactor piping failure, reaction chamber failure and heat exchanger failure. Since the chemical plant acts as the heat sink for the nuclear reactor, any of these accidents induce a loss-of-heat-sink accident in the nuclear reactor. In this paper, several chemical plant initiated accident scenarios are presented. The following accident scenarios are proposed: i) failure of the Bunsen chemical reactor; ii) product flow failure from either the H 2 SO 4 decomposition section or HI decomposition section; iii) reactant flow failure from either the H 2 SO 4 decomposition section or HI decomposition section; iv) rupture of a reaction chamber. Qualitative analysis of these accident scenarios indicates that each result in either partial or total loss of heat sink accidents for the nuclear reactor. These scenarios are reduced to two types: i) discharge rate limited accidents; ii) discontinuous reaction chamber accidents. A discharge rate limited rupture of the SO 3 decomposition section of the SI cycle is proposed and modelled. Since SO 3 decomposition occurs in the gaseous phase, critical flow out of the rupture is calculated assuming ideal gas behaviour. The accident scenario is modelled using a fully transient control volume model of the S-I cycle coupled to a THERMIX model of a 268 MW pebble bed modular reactor (PBMR-268) and a point kinetics model. The Bird, Stewart and Lightfoot source model for choked gas flows from a pressurised chamber was utilised as a discharge rate model. A discharge coefficient of 0.62 was assumed. Feedback due to the rupture is observed in the nuclear

Discussion on Design Transients of Pebble-bed High Temperature Gas-cooled Reactor

International Nuclear Information System (INIS)

Wang Yan; Li Fu; Zheng Yanhua

2014-01-01

In order to assure high quality for the components and their supports in the reactor coolant system, etc., some thermal-hydraulic transient conditions will be selected and researched for equipment design evaluation to satisfy the requirements ASME code, which are based on the conservative estimates of the magnitude and frequency of the temperature and pressure transients resulting from various operating conditions in the plant. In the mature design on pressurized water reactor, five conditions are considered. For the developing advanced pebble-bed high temperature gas-cooled reactor(HTGR), its design and operation has much difference with other reactors, so the transients of the pebble-bed high temperature gas-cooled reactor have distinctive characteristics. In this paper, the possible design transients of the pebble-bed HTGR will be discussed, and the frequency of design transients for equipment fatigue analysis and stress analysis due to cyclic stresses is also studied. The results will provide support for the design and construct of the pebble-bed HTGR. (author)

Paleoecology of the Late Pennsylvanian-age Calhoun coal bed and implications for long-term dynamics of wetland ecosystems

Energy Technology Data Exchange (ETDEWEB)

Willard, Debra A. [US Geological Survey, 926A National Center, Reston (VA 20192 USA); Phillips, Tom L. [Department of Plant Biology, University of Illinois, Urbana (IL 61801 USA); Lesnikowska, Alicia D. [Box 24, Rt. 2, Vineyard Haven (MA 02568 USA); DiMichele, William A. [Department of Paleobiology, NMNH, Smithsonian Institution, Washington (DC 20560 USA)

2007-01-02

Quantitative plant assemblage data from coal balls, miospores, megaspores, and compression floras from the Calhoun coal bed (Missourian) of the Illinois Basin (USA) are used to interpret spatial and temporal changes in plant communities in the paleo-peat swamp. Coal-ball and miospore floras from the Calhoun coal bed are dominated strongly by tree ferns, and pteridosperms and sigillarian lycopsids are subdominant, depending on geographic location within the coal bed. Although the overall composition of Calhoun peat-swamp assemblages is consistent both temporally and spatially, site-to-site differences and short-term shifts in species dominance indicate local topographic and hydrologic control on species composition within the broader context of the swamp. Statistical comparison of the Calhoun miospore assemblages with those from other Late Pennsylvanian coal beds suggests that the same basic species pool was represented in each peat-swamp landscape and that the relative patterns of dominance and diversity were persistent from site to site. Therefore, it appears that the relative patterns of proportional dominance stayed roughly the same from one coal bed to the next during Late Pennsylvanian glacially-driven climatic oscillations. (author)

Effect of different plant species in pilot constructed wetlands for wastewater reuse in agriculture

Directory of Open Access Journals (Sweden)

Salvatore Barbagallo

2013-09-01

Full Text Available In this paper the first results of an experiment carried out in Southern Italy (Sicily on the evapotranspiration (ET and removal in constructed wetlands with five plant species are presented. The pilot plant used for this study is made of twelve horizontal sub-surface flow constructed wetlands (each with a surface area of 4.5 m2 functioning in parallel, and it is used for tertiary treatment of part of the effluents from a conventional municipal wastewater treatment plant (trickling filter. Two beds are unplanted (control while ten beds are planted with five different macrophyte species: Cyperus papyrus, Vetiveria zizanoides, Miscanthus x giganteus, Arundo donax and Phragmites australis (i.e., every specie is planted in two beds to have a replication. The influent flow rate is measured in continuous by an electronic flow meter. The effluent is evaluated by an automatic system that measure the discharged volume for each bed. Physical, chemical and microbiological analyses were carried out on wastewater samples collected at the inlet of CW plant and at the outlet of the twelve beds. An automatic weather station is installed close to the experimental plant, measuring air temperature, wind speed and direction, rainfall, global radiation, relative humidity. This allows to calculate the reference Evapotranspiration (ET0 with the Penman-Monteith formula, while the ET of different plant species is measured through the water balance of the beds. The first results show no great differences in the mean removal performances of the different plant species for TSS, COD and E.coli, ranged from, respectively, 82% to 88%, 60% to 64% and 2.7 to 3.1 Ulog. The average removal efficiency of nutrient (64% for TN; 61 for NH4-N, 31% for PO4-P in the P.australis beds was higher than that other beds. From April to November 2012 ET measured for plant species were completely different from ET0 and ETcontrol, underlining the strong effect of vegetation. The cumulative

Continuous processing of recombinant proteins: integration of refolding and purification using simulated moving bed size-exclusion chromatography with buffer recycling.

Science.gov (United States)

Wellhoefer, Martin; Sprinzl, Wolfgang; Hahn, Rainer; Jungbauer, Alois

2014-04-11

Continuous processing of recombinant proteins was accomplished by combining continuous matrix-assisted refolding and purification by tandem simulated moving bed (SMB) size-exclusion chromatography (SEC). Recombinant proteins, N(pro) fusion proteins from inclusion bodies were dissolved with NaOH and refolded in the SMB system with a closed-loop set-up with refolding buffer as the desorbent buffer and buffer recycling of the refolding buffer of the raffinate by tangential flow filtration. For further purification of the refolded proteins, a second SMB operation also based on SEC was added. The whole system could be operated isocratically with refolding buffer as the desorbent buffer, and buffer recycling could also be applied in the purification step. Thus, a significant reduction in buffer consumption was achieved. The system was evaluated with two proteins, the N(pro) fusion pep6His and N(pro) fusion MCP-1. Refolding solution, which contained residual N(pro) fusion peptide, the cleaved autoprotease N(pro), and the cleaved target peptide was used as feed solution. Full separation of the cleaved target peptide from residual proteins was achieved at a purity and recovery in the raffinate and extract, respectively, of approximately 100%. In addition, more than 99% of the refolding buffer of the raffinate was recycled. A comparison of throughput, productivity, and buffer consumption of the integrated continuous process with two batch processes demonstrated that up to 60-fold higher throughput, up to 180-fold higher productivity, and at least 28-fold lower buffer consumption can be obtained by the integrated continuous process, which compensates for the higher complexity. Copyright © 2014 Elsevier B.V. All rights reserved.

Plants on the move: plant-soil interactions in poleward shifting plant species

NARCIS (Netherlands)

Grunsven, van R.H.A.

2008-01-01

As a result of recent global climate change, areas that have previously been climatically unsuitable for species have now become suitable new habitats. Many plant-species are expanding their range polewards, colonizing these newly available areas. If these species are able to expand their range

Experience gained in bench scale and pilot scale fluidised bed processing

CSIR Research Space (South Africa)

Hadley, TD

2005-01-01

Full Text Available of titanium dioxide. Expertise in the design and commissioning of industrial-scale plants has led to the supply (through licensees) of a biomass sludge incinerator/boiler generating 26t/h steam, a 20 MW high-sulphur pitch incinerator and a 12 MW fluidised bed...

Carbon capture from coal fired power plant using pressurized fluid bed technology

Energy Technology Data Exchange (ETDEWEB)

Williams, Dennis; Christensen, Tor

2010-09-15

This presentation will discuss the use of a pressurized fluid bed boiler system and specialized carbon capture system to burn coal and generagte clean electricity. The paper will present the existing boiler and carbon capture technology and present economics, thermal performance and emissions reduction for a 100Mw module.

Management bedding : vrijloopstal met composterende bedding van houtsnippers

NARCIS (Netherlands)

Boer, de H.C.; Wiersma, M.; Galama, P.J.; Szanto, G.L.

2015-01-01

In de vrijloopstal liggen de koeien meestal op een organische bedding en scheiden daar mest (feces en urine) uit. Om de bedding voldoende droog en schoon te houden wordt er regelmatig nieuw strooisel aangevoerd en wordt de toplaag bewerkt. Op basis van onderzoek- en praktijkervaringen tot nu toe

Pulverized coal vs. circulating fluidized bed: An economic comparison

International Nuclear Information System (INIS)

Johns, R.F.

1991-01-01

As the power industry looks to the 1990s for expanded steam generation capacity, boiler owners will continue on their long-standing assignment to evaluate and select the best, lowest cost alternative to meet their energy needs. For coal-fired plants, this evaluation process includes pulverized coal-fired boilers (PC) and circulating fluidized bed boilers (CFB). The cost difference between these products is site specific and depends on several variables, including: Boiler size, pressure, and temperature; Operating variables, such as the cost for fuel, auxiliary power, SO 2 reagent, and ash disposal; Capital cost; and Financial variables, such as evaluation period and interest rate. This paper provides a technical and economic comparison between a pulverized coal-fired boiler and circulating fluidized bed boiler

Investigation of the structure of debris beds formed from fuel rods fragmentation

Energy Technology Data Exchange (ETDEWEB)

Nguyen, Duc-Hanh; Fichot, Florian; Topin, Vincent, E-mail: vincent.topin@irsn.fr

2017-03-15

This paper is a study of debris beds that can form in the core of a nuclear power plant under severe accident conditions. Such beds are formed of fragments of pellets and cladding remnants, as observed in the TMI-2 core. Many important issues are related with the morphology of those debris beds: are they coolable in case of water injection and how does molten corium progress through them if they are not coolable? The answers to those questions depend on the structure of the debris bed: porosity, number and arrangement of particles. In order to obtain relevant information, a numerical simulation of the formation of the debris bed is proposed. It relies on a granular approach of the type called “Contact Dynamics” to simulate the collapse of debris and their accumulation. Two different schemes of fuel pellet fragmentation are considered and simulations for different degrees of fragmentation of the pellets are performed. The results show that the number of axial cracks on fuel pellets strongly influences the final porosity of the debris bed. Porosities vary between 31% (less coolable cases) and 45% (similar to TMI-2 observations), with a most probable configuration around 41%. The specific surface of the bed is also evaluated. In the last part, a simple model is used to estimate the impact of the variation in geometry of the numeric debris beds on their flow properties. We show that the permeability and passability can vary respectively with a range of 30% and 15% depending on the number of fragment per pellet. The other benefits of the approach are finally discussed. Among them, the possibility to print 3D samples from the calculated images of debris beds appears as a promising perspective to perform experiments with realistic debris beds.

Fabrication works on rotary kiln fluidized bed

International Nuclear Information System (INIS)

Shahazrin Mohd Nasir; Mohamad Azman Che Mat Isa; Mohamad Puad Haji Abu; Mohd Fairus Abdul Farid

2005-01-01

Rotary kiln has been widely used in incineration and studied by many researches. Solid wastes of various shapes, sizes and heat value can be fed into rotary kiln either in batches or continually. Waste combustion in rotary kiln involves rotation method and the residence time depends on the length and diameter of the rotary kiln and the total stichomythic air given to the system.Rocking system is another technology used in incinerator. In the rocking system, internal elements in the combustion chamber move to transports and mix the burning waste so that all combustible material in the waste is fully burnt. Another technology in incinerator is the fluidized bed. This method uses air to fluidized the sand thus enhancing the combustion process. The total air is controlled in order to obtain a suitable fluidized condition.This preliminary study was conducted to study the feasibility of an incinerator system when three components viz. the rotary kiln, rocking system and fluidized bed are combined. This research was also conducted to obtain preliminary data parameters of the three components such as the suitable temperature, the angle of the kiln, residence time, total air for fluidization, rocking speed and the devolatilization rate. The samples used in this research were the palm oil kernel shells. (Author)

State of the art and the future fuel portfolio of fluidized bed combustion systems; Status und kuenftiges Brennstoffportfolio bei Wirbelschichtfeuerungen

Energy Technology Data Exchange (ETDEWEB)

Szentannai, Pal; Friebert, Arpad; Winter, Franz [Technische Univ. Wien (Austria). Inst. fuer Verfahrens-, Umwelttechnik und technische Biowissenschaften

2008-07-01

Coal, biomass and substitute fuels energetically can be used efficiently and with low pollution in fluidized bed plants. In comparison to biomass there are significant differences between the circulating and stationary fluidized bed technology. The stationary fluidised bed is fed predominantly with biomasses and residual substances. Coal usually is the basis fuel in the circulating fluidised bed. Biomass and residual substances frequently are course-fired. The state of the art is the employment of a broad fuel mixture in small and large fluidized-bed combustion systems. Future developments present an increased use of sewage sludge, fluidized bed combustion systems with wood as a basis fuel, utilization of household waste and the gas production.

Theoretical and experimental investigation on adaptability of charcoal beds to containment filter venting in Italian nuclear power plant

International Nuclear Information System (INIS)

Caropreso, G.; Leonardi, A.; Perna, W.; Sgalambro, G.

1989-01-01

The work has been divided into three parts. The first one gives a description of the facilities under investigation during some selected accidental conditions, also described. The second part, which consists of an experimental work, tries to identify the behavior of charcoal beds in terms of pressure drop vs the aerosol mass loading and of aerosol retention efficiency. On the basis of the experimental findings, the prediction of the behavior of the real beds is carried out in the third part, as regards the pressure drop through the beds, related to the selected accident scenarios. In addition in this last part the results of a preliminary evaluation of the maximum decay power picked up by the beds without reaching the carbon self-ignition temperature have been reported

Poisonous plants: a guide for parents & childcare providers

National Research Council Canada - National Science Library

Dauncey, Elizabeth A

2010-01-01

.... Thomas' Hospital, London. Helpful descriptions and more than 230 photographs will assist you in identifying 132 of the most poisonous plants and plant groups likely to be encountered as pot plants, in flower beds...

Sediment Supply as a Control on Plant-Morphodynamic Interactions

Science.gov (United States)

Manners, R.; Wilcox, A. C.; Kui, L.; Stella, J. C.; Lightbody, A.; Sklar, L. S.

2014-12-01

The caliber and quantity of sediment delivered to a channel influences its size and shape, yet we know little about how the sediment supply affects rivers whose geomorphic form is influenced by riparian vegetation. We present results from flume experiments that test the impact of sediment supply on plant-morphodynamic interactions. We introduced two sediment supply conditions to a 28-meter long, sand bedded flume (60 cm wide and 71 cm deep) at the UC-Berkeley Richmond Field Station: equilibrium (balance between sediment transport and supply) and deficit (transport exceeds sediment supply). We conducted ten runs with different riparian seedling configurations (individual plants or patches) and species (tamarisk or cottonwood), and stem and leaf density (0.003-0.47 cm2/cm2), under both sediment supply conditions. Plant species, size, and configuration were important in predicting the topographic adjustments that occurred during our experiments. These influences may be attributed to differences in plant morphology; tamarisk is shrubby while cottonwood is more tree-like, with a single stem and leaves concentrated higher on the plant. The plant-morphodynamic relationship, however, differed for the two sediment supply conditions. During sediment equilibrium, only patches of cottonwood served as sediment sinks compared to an unvegetated bed, but tamarisk patches had no impact on the sediment mass balance. During sediment deficit, in contrast, tamarisk patches accumulated more sediment than unvegetated beds. Stem and leaf density also controlled changes in bed elevation. During equilibrium conditions, increasing the density of cottonwood stems and leaves resulted in greater bed degradation. Conversely, aggradation occurred with increases in the density of tamarisk. For sediment deficit conditions, the relationship between stem and leaf density and the rate of bed change was negative for both species (i.e., higher density resulted in faster rate of scour). The shifting

Effect of bed particles to combustion of gases in fluidized bed

Energy Technology Data Exchange (ETDEWEB)

Raiko, R.; Wallen, V.; Etelaeaho, R.; Correia, S. [Tampere Univ. of Technology (Finland). Energy and Process Engineering

1997-10-01

The objective of this project was to obtain experimental data on effects of sand particles to the combustion of gases. The effect of the surface area of the particles was tested using different sized particles. The fluidized bed reactor used in these experiments was a stainless-steel tube with an internal diameter of 42 mm surrounded by an electric heater. The test rig was built in the Laboratory of Energy and Process Engineering at Tampere University of Technology. In order to elucidate the possible changes of particle surface, microscopic and porosimetric studies were conducted with both fresh bed particles and used bed particles. These measurements indicate that carbon monoxide significantly reacts with oxygen in the particulate or emulsion phase of a fluidized bed, if the residence time is long enough. The reaction rate depends mainly on temperature, air coefficient, residence time and particle size of the solids. It seems that the combustion enhances if the average particle size increases. Whether this is caused by increased free path length or reduced specific surface area of the bed is yet unknown. The first might be more probable cause because the majority of reactions often took place in the freeboard right above the bed. It was clear that the bed hindered proper combustion in several cases. (orig.)

Biofuels 2.0 move to pilot plant

International Nuclear Information System (INIS)

Dupin, L.

2010-01-01

The second generation of biofuels, which use the non-energy parts of plants, do not compete with the food industry. These biofuels have been tried and tested at the laboratory but challenges are occurring with the transition to industrial plants. Demonstrators and prototypes are developing in Germany, Japan, USA and France and bet on two different processes, the biochemical way (enzymatic reaction and fermentation) and the thermochemical way (gasification and Fischer-Tropsch synthesis). Research is in progress on a possible third generation of biofuels which will use micro-algae. The interest of this third way is triple: no competition with the food industry, no land use (production in bioreactors), and enhanced CO 2 capture. (J.S.)

Experiment and modeling of low-concentration methane catalytic combustion in a fluidized bed reactor

International Nuclear Information System (INIS)

Yang, Zhongqing; Yang, Peng; Zhang, Li; Guo, Mingnv; Ran, Jingyu

2016-01-01

decrease. In contrast, there is very little change in the homogeneous zone, meaning that combustion mainly occurs in the dense zone and moves toward the lower part of the bed with increasing bed temperature.

Bed retained products in swept fixed bed (SFB) coal hydropyrolysis

Energy Technology Data Exchange (ETDEWEB)

Mastral, A.M.; Perez-Surio, M.J. [CSIC, Zaragosa (Spain). Inst. de Carboquimica

1997-12-31

The hydropyrolysis of a low rank coal in a swept fixed bed (SFB) reactor is carried out by fixing the hydrogen pressure (40 kg/cm{sup 2}), the hydrogen flow (2 l/min) and the residence time (10 min) at increasing temperatures (400 C, 500 C and 600 C) and coal bed heights (h, 1.5h, 2h, 2.5h and 3h). It is shown that the percentages of tars and char directly depend on the coal bed height and that there is not only a quantitative dependence, but also the height of the coal bed is very important and plays a relevant role on the nature of the conversion products. (orig.)

Cooling of a polyethylene tunnel type greenhouse by means of a rock bed

Energy Technology Data Exchange (ETDEWEB)

Kurklu, Ahmet; Bilgin, Sefai [Akdeniz Univ., Dept. of Agricultural Mechanisation, Antalya (Turkey)

2004-10-01

An experiment was conducted to cool a 15 m{sup 2} ground area plastic-tunnel-type greenhouse by the use of a rock bed. An identical greenhouse with no rock bed was also erected for control purposes. Two rock-bed canals, each with the dimensions of 3 x l.25 x 0.75 m, were dug in the soil of the experimental greenhouse. After the canals were filled with the rocks and insulated, the top surface was covered by a soil layer of thickness enough for the root development depth of the plants. Air was pushed through the rock bed by a centrifugal fan with a 1100 m{sup 3}/h flow rate. Energy stored in the rock bed during the day was dumped outside the greenhouse at night using the cooler outside air. The results of the measurements showed that the rock-bed system maintained air temperature 14 deg C lower at maximum in the experimental greenhouse than the control one. The temperature difference seemed to increase with increasing solar radiation and outside air temperature. Relative humidity during the day remained at about 40% in the experimental greenhouse and was always higher than that in the control one. The coefficient of performance (COP) of the rock-bed system was higher than 3 in general, and it was observed that this value increased with decreasing rock-bed temperature. The average solar collection efficiency was 38%. The rock-bed system seems to have a significant potential for cooling applications in greenhouses. (Author)

STUDY ON USING A TRICKLE-BED BIOREACTOR FOR REDUCING VOLATILE ORGANIC COMPOUNDS IN WASTEWATER TREATMENT PLANT OPERATED BY PKN ORLEN S.A.

Directory of Open Access Journals (Sweden)

Arkadiusz Kamiński

2017-08-01

Full Text Available The results of studies conducted by Ekoinwentyka sp. z o.o. concerning the possibility of using a trickle-bed bioreactor for reducing of volatile organic compounds (VOCs emitted by PKN ORLEN S.A. wastewater treatment plant were presented and discussed. During the one-month trial, inlet and outlet concentrations of VOCs, H2S and NH3 were analysed and the efficiency of bio-purification process was determined on their basis. The obtained results confirmed the effectiveness of the applied technology under the given conditions, simultaneously demonstrating the validity of conducting further technological analysis to derive the design assumptions of the bioreactor on the industrial scale.

Waste Treatment And Immobilization Plant U. S. Department Of Energy Office Of River Protection Submerged Bed Scrubber Condensate Disposition Project - Abstract # 13460

Energy Technology Data Exchange (ETDEWEB)

Yanochko, Ronald M [Washington River Protection Solutions, Richland, WA (United States); Corcoran, Connie [AEM Consulting, LLC, Richland, WA (United States)

2012-11-15

The Hanford Waste Treatment and Immobilization Plant (WTP) will generate an off-gas treatment system secondary liquid waste stream [submerged bed scrubber (SBS) condensate], which is currently planned for recycle back to the WTP Low Activity Waste (LAW) melter. This SBS condensate waste stream is high in Tc-99, which is not efficiently captured in the vitrified glass matrix. A pre-conceptual engineering study was prepared in fiscal year 2012 to evaluate alternate flow paths for melter off-gas secondary liquid waste generated by the WTP LAW facility. This study evaluated alternatives for direct off-site disposal of this SBS without pre-treatment, which mitigates potential issues associated with recycling.

Ecotoxicological bioassays of sediment leachates in a river bed flanked by decommissioned pesticide plants in Nantong City, East China.

Science.gov (United States)

Zhou, Yan; Wang, Fenghe; Wan, Jinzhong; He, Jian; Li, Qun; Qiang Chen; Gao, Jay; Lin, Yusuo; Zhang, Shengtian

2017-03-01

Traditionally, the toxicity of river contaminants is analyzed chemically or physically through river bed sediments. The biotoxicity of polluted sediment leachates has not caught our attention. This study aims to overcome this deficiency through a battery of biotests which were conducted to monitor comprehensive toxicity of sediment leachates for the Yaogang River in East Jiangsu Province of China, which is in close proximity to former pesticide plants. The general physical and chemical parameters of major pollutants were analyzed from river bed sediments collected at five strategic locations. The ecotoxicity analyses undertaken include overall fish (adult zebrafish) acute toxicity, luminescent bacteria (Vibrio fischeri) bioassay, and zebrafish embryo toxicity assay. Compared with the control group, sediment leachates increased the lethality, inhibited the embryos hatching and induced development abnormalities of zebrafish embryos, and inhibited the luminescence of V. fischeri. The results show that sediment leachates may assume various toxic effects, depending on the test organism. This diverse toxicity to aquatic organisms reflects their different sensitivity to sediment leachates. It is found clearly that V. fischeri was the organism which was characterized by the highest sensitivity to the sediment leachates. The complicated toxicity of leachates was not caused by one single factor but by multiple pollutants together. This indicates the need of estimations of sediment leachate not only taking into account chemical detection but also of applying the biotests to the problem. Thus, multigroup bioassays are necessary to realistically evaluate river ecological risks imposed by leachates.

In-bed accountability of tritium in production scale metal hydride storage beds

International Nuclear Information System (INIS)

Klein, J.E.

1995-01-01

An ''in-bed accountability'' (IBA) flowing gas calorimetric measurement method has been developed and implemented to eliminate the need to remove tritium from production scale metal hydride storage beds for inventory measurement purposes. Six-point tritium IBA calibration curves have been completed for two, 390 gram tritium metal hydride storage beds. The calibration curves for the two tritium beds are similar to those obtained from the ''cold'' test program. Tritium inventory errors at the 95 percent confidence level ranged from ± 7.3 to 8.6 grams for the cold test results compared to ± 4.2 to 7.5 grams obtained for the two tritium calibrated beds

Preliminary market assessment of fluidized-bed waste-heat recovery technology

Energy Technology Data Exchange (ETDEWEB)

Campos, F.T.; Fey, C.L.; Grogan, P.J.; Klein, N.P.

1980-06-01

A preliminary assessment of fluidized-bed waste-heat recovery (FBWHR) system market potential is presented with emphasis on the factors influencing industrial acceptability. Preliminary market potential areas are identified based on the availability of waste heat. Trends in energy use are examined to see the effect they might have on these market potential areas in the future. Focus groups interviews are used to explore important factors in the industrial decision-making process. These important factors are explored quantitatively in a survey of industrial plant engineers. The survey deals with the waste-heat boiler configuration of the FBWHR system. Results indicate market acceptance of the fluidized-bed waste-heat boiler could be quite low.

Resuspension created by bedload transport of macroalgae

DEFF Research Database (Denmark)

Canal Vergés, Paula; Kristensen, Erik; Flindt, Mogens

2009-01-01

surface sediment while drifting as bed load. To improve the understanding of this ballistic effect of moving plants on the sediment surface, controlled annular flume experiments were performed. Plant transport was measured together with turbidity and suspended particulate matter during increasing water...

Comparing chemical and biological control strategies for twospotted spider mites (Acari: Tetranychidae) in commercial greenhouse production of bedding plants.

Science.gov (United States)

Opit, George P; Perret, Jamis; Holt, Kiffnie; Nechols, James R; Margolies, David C; Williams, Kimberly A

2009-02-01

Efficacy, costs, and impact on crop salability of various biological and chemical control strategies for Tetranychus urticae Koch (Acari: Tetranychidae) were evaluated on mixed plantings of impatiens, Impatiens wallerana Hook.f (Ericales: Balsaminaceae), and ivy geranium, Pelargonium peltatum (1.) L'Hér. Ex Aiton (Geraniales: Geraniaceae), cultivars in commercial greenhouses. Chemical control consisting of the miticide bifenazate (Floramite) was compared with two biological control strategies using the predatory mite Phytoseiulus persimilis Athias-Henriot (Acari: Phytoseiidae). Treatments were 1) a single, early application of bifenazate; 2) a single, early release of predatory mites at a 1:4 predator:pest ratio based on leaf samples to estimate pest density; 3) a weekly release of predatory mites at numbers based on the area covered by the crop; and 4) an untreated control. T. urticae populations were monitored for 3 wk after the earliest treatment. When plants were ready for market, their salability was estimated. Bifenazate and density-based P. persimilis treatments effectively reduced T. urticae numbers starting 1 wk after plants had been treated, whereas the scheduled, area-based P. persimilis treatment had little or no effect. The percentage of flats that could be sold at the highest market wholesale price ranged from 15 to 33%, 44 to 86%, 84 to 95%, and 92 to 100%, in the control, weekly area-based P. persimilis, bifenazate, and single density-based P. persimilis treatments, respectively. We have shown that in commercial greenhouse production of herbaceous ornamental bedding plants, estimating pest density to determine the appropriate number of predators to release is as effective and offers nearly the same economic benefit as prophylactic use of pesticides.

Thermal Analysis of Fluidized Bed and Fixed Bed Latent Heat Thermal Storage System

Science.gov (United States)

Beemkumar, N.; Karthikeyan, A.; Shiva Keshava Reddy, Kota; Rajesh, Kona; Anderson, A.

2017-05-01

Thermal energy storage technology is essential because its stores available energy at low cost. Objective of the work is to store the thermal energy in a most efficient method. This work is deal with thermal analysis of fluidized bed and fixed bed latent heat thermal storage (LHTS) system with different encapsulation materials (aluminium, brass and copper). D-Mannitol has been used as phase change material (PCM). Encapsulation material which is in orbicular shape with 4 inch diameter and 2 mm thickness orbicular shaped product is used. Therminol-66 is used as a heat transfer fluid (HTF). Arrangement of encapsulation material is done in two ways namely fluidized bed and fixed bed thermal storage system. Comparison was made between the performance of fixed bed and fluidized bed with different encapsulation material. It is observed that from the economical point of view aluminium in fluidized bed LHTS System has highest efficiency than copper and brass. The thermal energy storage system can be analyzed with fixed bed by varying mass flow rate of oil paves a way to find effective heat energy transfer.

Biological reduction of nitrate wastewater using fluidized-bed bioreactors

International Nuclear Information System (INIS)

Walker, J.F. Jr.; Hancher, C.W.; Patton, B.D.; Kowalchuk, M.

1981-01-01

There are a number of nitrate-containing wastewater sources, as concentrated as 30 wt % NO 3 - and as large as 2000 m 3 /d, in the nuclear fuel cycle as well as in many commercial processes such as fertilizer production, paper manufacturing, and metal finishing. These nitrate-containing wastewater sources can be successfully biologically denitrified to meet discharge standards in the range of 10 to 20 gN(NO 3 - )/m 3 by the use of a fluidized-bed bioreactor. The major strain of denitrification bacteria is Pseudomonas which was derived from garden soil. In the fluidized-bed bioreactor the bacteria are allowed to attach to 0.25 to 0.50-mm-diam coal particles, which are fluidized by the upward flow of influent wastewater. Maintaining the bacteria-to-coal weight ratio at approximately 1:10 results in a bioreactor bacteria loading of greater than 20,000 g/m 3 . A description is given of the results of two biodenitrification R and D pilot plant programs based on the use of fluidized bioreactors capable of operating at nitrate levels up to 7000 g/m 3 and achieving denitrification rates as high as 80 gN(NO 3 - )/d per liter of empty bioreactor volume. The first of these pilot plant programs consisted of two 0.2-m-diam bioreactors, each with a height of 6.3 m and a volume of 208 liters, operating in series. The second pilot plant was used to determine the diameter dependence of the reactors by using a 0.5-m-diam reactor with a height of 6.3 m and a volume of 1200 liters. These pilot plants operated for a period of six months and two months respectively, while using both a synthetic waste and the actual waste from a gaseous diffusion plant operated by Goodyear Atomic Corporation

Fluid bed porosity equation for an inverse fluidized bed bioreactor with particles growing biofilm

International Nuclear Information System (INIS)

Campos-Diaz, K. E.; Limas-Ballesteros, R.

2009-01-01

Fluid Bed Bioreactor performance is strongly affected by bed void fraction or bed porosity fluctuations. Particle size enlargement due to biofilm growth is an important factor that is involved in these variations and until now there are no mathematical equations that consider biofilm growth. In this work a mathematical equation is proposed to calculate bed void fraction in an inverse fluid bed bioreactor. (Author)

Trickle bed reactor model to simulate the performance of commercial diesel hydrotreating unit

Energy Technology Data Exchange (ETDEWEB)

C. Murali; R.K. Voolapalli; N. Ravichander; D.T. Gokak; N.V. Choudary [Bharat Petroleum Corporation Ltd., Udyog Kendra (India). Corporate R& amp; D Centre

2007-05-15

A two phase mathematical model was developed to simulate the performance of bench scale and commercial hydrotreating reactors. Major hydrotreating reactions, namely, hydrodesulphurization, hydrodearomatization and olefins saturation were modeled. Experiments were carried out in a fixed bed reactor to study the effect of different process variables and these results were used for estimating kinetic parameters. Significant amount of feed vaporization (20-50%) was estimated under normal operating conditions of DHDS suggesting the importance of considering feed vaporization in DHDS modeling. The model was validated with plant operating data, under close to ultra low sulphur levels by correctly accounting for feed vaporization in heat balance relations and appropriate use of hydrodynamic correlations. The model could predict the product quality, reactor bed temperature profiles and chemical hydrogen consumption in commercial plant adequately. 14 refs., 7 figs., 6 tabs.

FY 1992 report on the results of the development of an entrained bed coal gasification power plant. Part 4. Operation of pilot plant; 1992 nendo seika hokokusho. Funryusho sekitan gaska hatsuden plant kaihatsu - Sono 4. Pilot plant unten sosa hen

Energy Technology Data Exchange (ETDEWEB)

NONE

1994-02-01

A record was summarized of the operation test study in FY 1992 of the 200 t/d entrained bed coal gasification pilot plant that was constructed with the aim of establishing technology of the integrated coal gasification combined cycle power generation. The operating hour of gasifier facilities in FY 1992 was 635 hours 19 minutes, and the number of times of gasification operation was 9. The operating hour of letting gas through to gas refining facilities was 549 hours 14 minutes. The operating hour of gas turbine facilities was 310 hours 18 minutes, and the generated output was 1,366.2 MWh. The operating hour of treatment furnace of safety environment facilities was 1,401 hours 4 minutes, and that of the denitrification system was 621 hours 24 minutes. As to the actual results of the start-up/stop, the paper detailedly recorded those of RUNs 10, 11, 12, 13 and D1. Further, operation manuals were made for the schedule of plant start-up/stop, gasifier facilities, gas refining facilities (dry desulfurization facilities), gas refining facilities (dry dedusting facilities), actual pressure/actual size combustor testing facilities and safety environment facilities. (NEDO)

Effect of Planting Patterns' and Plant Population on Some of Morphological Traits, Harvest Index and Conservable Grain Yield of Sweet Corn

Directory of Open Access Journals (Sweden)

M. Nasrolah Alhossini

2012-04-01

Full Text Available Sweet corn is one of the most important crops in Iran and due to its short period of growth, it has been an important position after wheat and barley in khorasane Razavi Province. In this study two methods of planting (one raised bed and furrow planting and 3 plant densities (65000, 75000 and 85000 plant/ha was evaluated on some of Morphological Traits, harvest index and conservable grain yield of sweet Corn(Chase and KSC403su Varieties in Torbat-e-Heidarie in saline (4.060ds/m condition on 2009. The experimental design was factorial based on RCBC with 4 replications. The result of ANOVA showed significant differences between Anthesis silking interval (ASI, tassel length, plant height, ear height, stem diameter, harvest index, and conservable grain yield of sweet corn varieties that effected by planting methods. the highest harvest index was belonged to Chase in 75000 Plant/ha on one raised bed planting method with 31.75% and the lowest mean was belonged to KSC403su in 85000 Plant/ha on furrow planting method with 14.93%. In addition the highest grain yield was belonged to chase variety at 75000 plant/ha and furrow planting method with 11.912 ton/ha, while the lowest grain yield was belonged to KSC403su variety at 85000 plant/ha and raised bed planting (3.610 ton/ha. The Chase variety was better than KSC403su Due to its canopy and photo period is shorter than KSC403su. The superiority of Chase variety can be related to better distribution of leaves, highest harvest index, conservable grain yield and plant arrangement in the row.

Incineration of Sludge in a Fluidized-Bed Combustor

OpenAIRE

Chien-Song Chyang; Yu-Chi Wang

2017-01-01

For sludge disposal, incineration is considered to be better than direct burial because of regulations and space limitations in Taiwan. Additionally, burial after incineration can effectively prolong the lifespan of a landfill. Therefore, it is the most satisfactory method for treating sludge at present. Of the various incineration technologies, the fluidized bed incinerator is a suitable choice due to its fuel flexibility. In this work, sludge generated from industrial plants was treated in ...

Crescimento do morangueiro: influência da cultivar e da posição da planta no canteiro Strawberry growth: effect of cultivar and plant position in the bed

Directory of Open Access Journals (Sweden)

André Samuel Strassburger

2011-02-01

Full Text Available O objetivo deste trabalho foi avaliar o crescimento de cultivares de morangueiro em sistema de cultivo orgânico, observando a influência da posição da planta no canteiro sobre a produção acumulada e a partição de massa seca entre os órgãos aéreos das plantas. O experimento foi realizado na Embrapa Clima Temperado, Estação Experimental Cascata, Pelotas, RS. Os tratamentos constaram da combinação de dois fatores experimentais: cultivar ('Albion', 'Aromas', 'Camarosa' e 'Camino Real' e a posição das plantas no canteiro (Central e Bordadura. O delineamento experimental adotado foi o de blocos completos casualizados com parcelas divididas e quatro repetições. A cultivar 'Camarosa' apresentou maior produção de massa seca dos órgãos aéreos das plantas (62,3; 27,5 e 88,0g planta-1 para folha, coroa e frutos, respectivamente e, juntamente com a 'Aromas', maior produtividade (64,2 e 59,1Mg ha-1, respectivamente. A cultivar 'Aromas' apresentou a maior contribuição proporcional dos frutos para a composição do total de massa seca da planta (60,6% e o maior índice de colheita (88%. A posição das plantas não influenciou o crescimento e a produtividade, indicando ausência de efeito de bordadura para as cultivares 'Albion', 'Aromas', 'Camarosa' e 'Camino Real'.The aim of this research was to evaluate the growth of strawberry cultivars growing in organic crop system observing the influence of plant position in the bed on accumulated dry matter production and its partitioning among the aboveground plant organs. The experiment was conducted in Embrapa Clima Temperado, Estação Experimental Cascata, Pelotas, RS. The treatments were compose by the combination of two experimental factors: cultivar ('Aromas', 'Albion', 'Camarosa' and 'Camino Real' and plant position in the bed (Central and Border. The experimental design used was randomized blocks with split-plots and four replications. 'Camarosa' cultivar presented highest dry mass

Raised bed technology for wheat crop in irrigated areas of punjab, pakistan

International Nuclear Information System (INIS)

Taj, S.; Ali, A.; Akmal, N.; Yaqoob, S.; Ali, M.

2013-01-01

The present paper analyzes the determinants of adoption of raised bed planting of wheat in irrigated areas of Punjab, Pakistan. Wheat is an important staple food of Pakistan. It contributes 13 % to the value added in agriculture and 2.6 % to the GDP. The agrarian economy of Pakistan is continuously under stress due to the low yield of almost all the crops and constrained with many problem. One of the most important issues of agriculture is water shortage which is increasing day by day and is a major challenge now a days. Therefore, water saving becomes the utmost need of the hour. The national research system is now putting their focus and efforts to manage the precious water through various modern/latest water saving models to draw some solid method of irrigation with less wastage. Raised bed planting method is also one of the modern methods of planting crop with significant water saving. The study was planned and conducted by the Social Sciences Research Institute, Faisalabad in 2011-12 to assess the determinants of the adoption of the raised bed technology for wheat crop in irrigated Punjab, Pakistan. The study was conducted at three sites of the districts Faisalabad and Toba Tek Singh where the Water Management Research Institute, University of Faisalabad promoted the raised bed technology for wheat crop. A sample of 63 farmers was interviewed in detail to understand the whole system and the factors contributing to the adoption of the technology. The study revealed that adopters typically have a more favorable resource base and tend to variously outperform non-adopters. More access to education and other social indicators increases the chances to adopt new technologies by the farming community. However, the small farmers can also be benefited with the technology with proper education regarding the technology in the area with good social mobilization for the conservation of scarce and valuable farm resources. (author)

Removal of personal care compounds from sewage sludge in reed bed container (lysimeter) studies--effects of macrophytes.

Science.gov (United States)

Chen, Xijuan; Pauly, Udo; Rehfus, Stefan; Bester, Kai

2009-10-15

Sludge reed beds have been used for dewatering (draining and evapotranspiration) and mineralisation of sludge in Europe since 1988. Although reed beds are considered as a low cost and low contamination method in reducing volume, breaking down organic matter and increasing the density of sludge, it is not yet clear whether this enhanced biological treatment is suitable for degradation of organic micro-pollutants such as personal care products. Within this project the effect of biological sludge treatment in a reed bed on reducing the concentrations of the fragrances HHCB, AHTN, OTNE was studied as on the bactericide Triclosan. Additionally, the capacity of different macrophytes species to affect the treatment process was examined. Three different macrophyte species were compared: bulrush (Typha latifolia), reed (Phragmites australis) and reed canary grass (Phalaris arundinacea). They were planted into containers (lysimeters) with a size of 1 m x 1 m x 1 m which were filled with 20 cm gravel at the bottom and 50 cm sludge on top, into which the macrophytes were planted. During the twelve months experiment reduction of 20-30% for HHCB and AHTN, 70% for Triclosan and 70% for OTNE were determined under environmental conditions. The reduction is most likely due to degradation, since volatilization, uptake into plants and leaching are insignificant. No difference between the containers with different macrophyte species or the unplanted containers was observed. Considering the usual operation time of 10 years for reed beds, an assessment was made for the whole life time.

Status and threats on seagrass beds using GIS in Vietnam

Science.gov (United States)

Luong, Cao Van; Thao, Nguyen Van; Komatsu, Teruhisa; Ve, Nguyen Dac; Tien, Dam Duc

2012-10-01

Seagrasses, marine flowering plants, are widely distributed along temperate and tropical coastlines of the world. Seagrasses have key ecological roles in coastal ecosystems and can form extensive meadows supporting high biodiversity. Till now, fourteen seagrass species belonging to four families were found in Vietnam: Halophila beccarii, H. decipiens, H. ovalis, H. minor, Thalassia hemprichii, Enhalus acoroides, Ruppia maritima, Halodule pinifolia, H. uninervis, Syringodium isoetifolium, Cymadocea rotundata, C. serrulata and Thalassodendron ciliatum. A total area of seagrass beds in Vietnam is estimated to be approximately 17000 ha by satellite images and GIS technology. In recent years, the distribution areas and densities of seagrass beds in Vietnam have been serious decreased compared with those 10-15 years ago. The decline level depended on the impacts by the natural process, the economical activities and the conservation awareness of local people. Thus, it is different at each coastal area. Generally speaking, the distribution areas and densities of seagrass beds were decreased by more than 50%. Seagrasses on tidal flats in some areas such as Quang Ninh, Hai Phong, Phu Quoc seem to be nearly lost. The distribution areas of seagrass beds in 2009 at Tam Giang-Cau Hai lagoon and Cua Dai estuary was decreased by 50-70% of those in early 1990s.

Pebble-bed reactor

International Nuclear Information System (INIS)

Lohnert, G.; Mueller-Frank, U.; Heil, J.

1976-01-01

A pebble-bed nuclear reactor of large power rating comprises a container having a funnel-shaped bottom forming a pebble run-out having a centrally positioned outlet. A bed of downwardly-flowing substantially spherical nuclear fuel pebbles is positioned in the container and forms a reactive nuclear core maintained by feeding unused pebbles to the bed's top surface while used or burned-out pebbles run out and discharge through the outlet. A substantially conical body with its apex pointing upwardly and its periphery spaced from the periphery of the container spreads the bottom of the bed outwardly to provide an annular flow down the funnel-shaped bottom forming the runout, to the discharge outlet. This provides a largely constant downward velocity of the spheres throughout the diameter of the bed throughout a substantial portion of the down travel, so that all spheres reach about the same burned-out condition when they leave the core, after a single pass through the core area

Report on the results of the R and D of a 200 t/d entrained bed coal gasification pilot plant. Summary - Part 2. Volume 3: Results of the study operation and the evaluation; 1986- 200t/nichi funryusho sekitan gaska hatsuden pilot plant no kenkyu seika hokokusho (Matome). Sono 2. Dai 3 hen kenkyu unten seika to sono hyoka

Energy Technology Data Exchange (ETDEWEB)

NONE

1997-01-01

A project was finished which had been carried out for 11 years since 1986 for technology of the entrained bed coal gasification power generation technology using a 200 t/d coal gasification combined cycle power generation pilot plant, and it was comprehensively summed up. In Volume 3: Results of the study operation and the evaluation, the following were summarized on gasifier: gasification performance of 200 t/d furnace, operation ability of the bituminous coal supply system, stability of char recovery, deposition of slag and char in furnace, discharge characteristics of molten slag, operation characteristics, etc. The following on gas refining facilities: dry desulfurizer, dust remover, new gas refining equipment (fixed bed dust removal/desulfurization system, packed bed desulfuriztion/dust removal system), etc. The following on gas turbine facilities: 12.5 MW gas turbine, large gas turbine, large gas turbine combustor, etc. Additionally, the paper summarized the control system and total function, operation characteristics of the whole pilot plant, relations of environmental preservation, study of the effective slag utilization, collection/study of unfavorable conditions/troubles and matters for the reflection, etc. (NEDO)

Apparatus for controlling fluidized beds

Science.gov (United States)

Rehmat, A.G.; Patel, J.G.

1987-05-12

An apparatus and process are disclosed for control and maintenance of fluidized beds under non-steady state conditions. An ash removal conduit is provided for removing solid particulates from a fluidized bed separate from an ash discharge conduit in the lower portion of the grate supporting such a bed. The apparatus and process of this invention is particularly suitable for use in ash agglomerating fluidized beds and provides control of the fluidized bed before ash agglomeration is initiated and during upset conditions resulting in stable, sinter-free fluidized bed maintenance. 2 figs.

Experimental study of flow field characteristics on bed configurations in the pebble bed reactor

International Nuclear Information System (INIS)

Jia, Xinlong; Gui, Nan; Yang, Xingtuan; Tu, Jiyuan; Jia, Haijun; Jiang, Shengyao

2017-01-01

Highlights: • PTV study of flow fields of pebble bed reactor with different configurations are carried out. • Some criteria are proposed to quantify vertical velocity field and flow uniformity. • The effect of different pebble bed configurations is also compared by the proposed criteria. • The displacement thickness is used analogically to analyze flow field characteristics. • The effect of mass flow variation in the stagnated region of the funnel flow is measured. - Abstract: The flow field characteristics are of fundamental importance in the design work of the pebble bed high temperature gas cooled reactor (HTGR). The different effects of bed configurations on the flow characteristics of pebble bed are studied through the PTV (Particle Tracking Velocimetry) experiment. Some criteria, e.g. flow uniformity (σ) and mass flow level (α), are proposed to estimate vertical velocity field and compare the bed configurations. The distribution of the Δθ (angle difference between the individual particle velocity and the velocity vector sum of all particles) is also used to estimate the resultant motion consistency level. Moreover, for each bed configuration, the thickness of displacement is analyzed to measure the effect of the funnel flow zone based on the boundary layer theory. Detailed information shows the quantified characteristics of bed configuration effects on flow uniformity and other characteristics; and the sequence of levels of each estimation criterion is obtained for all bed configurations. In addition, a good design of the pebble bed configuration is suggested and these estimation criteria can be also applied and adopted in testing other geometry designs of pebble bed.

Three-dimensional flow structure and patterns of bed shear stress in an evolving compound meander bend

Science.gov (United States)

Engel, Frank; Rhoads, Bruce L.

2016-01-01

Compound meander bends with multiple lobes of maximum curvature are common in actively evolving lowland rivers. Interaction among spatial patterns of mean flow, turbulence, bed morphology, bank failures and channel migration in compound bends is poorly understood. In this paper, acoustic Doppler current profiler (ADCP) measurements of the three-dimensional (3D) flow velocities in a compound bend are examined to evaluate the influence of channel curvature and hydrologic variability on the structure of flow within the bend. Flow structure at various flow stages is related to changes in bed morphology over the study timeframe. Increases in local curvature within the upstream lobe of the bend reduce outer bank velocities at morphologically significant flows, creating a region that protects the bank from high momentum flow and high bed shear stresses. The dimensionless radius of curvature in the upstream lobe is one-third less than that of the downstream lobe, with average bank erosion rates less than half of the erosion rates for the downstream lobe. Higher bank erosion rates within the downstream lobe correspond to the shift in a core of high velocity and bed shear stresses toward the outer bank as flow moves through the two lobes. These erosion patterns provide a mechanism for continued migration of the downstream lobe in the near future. Bed material size distributions within the bend correspond to spatial patterns of bed shear stress magnitudes, indicating that bed material sorting within the bend is governed by bed shear stress. Results suggest that patterns of flow, sediment entrainment, and planform evolution in compound meander bends are more complex than in simple meander bends. Moreover, interactions among local influences on the flow, such as woody debris, local topographic steering, and locally high curvature, tend to cause compound bends to evolve toward increasing planform complexity over time rather than stable configurations.

Bed diameter effects and incipient slugging in gas fluidized beds

International Nuclear Information System (INIS)

Agarwal, P.K.

1986-01-01

The coalescence and growth of bubble swarms formed at the distributor of a fluidized bed gives rise to lateral as well as vertical distributions of bubble properties. However, existing models employ average bubble properties obtained largely from semi-empirical considerations. In a recent Paper, the author developed a bubble growth model based on a population balance approach. Analytical expressions were derived for the bubble characteristic distributions and averages. However, the model, developed for unconstrained growth, did not take into account the effect of the bed diameter and the possibility of slugging. In this Paper, the model is extended to take these aspects into account. A slugging criterion is also developed which is expected to be valid for the regime where incipient slugging depends on the bed height as well as the region where bed height does not significantly affect minimum slugging conditions

Waste Treatment And Immobilization Plant U. S. Department Of Energy Office Of River Protection Submerged Bed Scrubber Condensate Disposition Project - Abstract no. 13460

International Nuclear Information System (INIS)

Yanochko, Ronald M; Corcoran, Connie

2012-01-01

The Hanford Waste Treatment and Immobilization Plant (WTP) will generate an off-gas treatment system secondary liquid waste stream [submerged bed scrubber (SBS) condensate], which is currently planned for recycle back to the WTP Low Activity Waste (LAW) melter. This SBS condensate waste stream is high in Tc-99, which is not efficiently captured in the vitrified glass matrix. A pre-conceptual engineering study was prepared in fiscal year 2012 to evaluate alternate flow paths for melter off-gas secondary liquid waste generated by the WTP LAW facility. This study evaluated alternatives for direct off-site disposal of this SBS without pre-treatment, which mitigates potential issues associated with recycling

Advanced Core Design And Fuel Management For Pebble-Bed Reactors

Energy Technology Data Exchange (ETDEWEB)

Hans D. Gougar; Abderrafi M. Ougouag; William K. Terry

2004-10-01

A method for designing and optimizing recirculating pebble-bed reactor cores is presented. At the heart of the method is a new reactor physics computer code, PEBBED, which accurately and efficiently computes the neutronic and material properties of the asymptotic (equilibrium) fuel cycle. This core state is shown to be unique for a given core geometry, power level, discharge burnup, and fuel circulation policy. Fuel circulation in the pebble-bed can be described in terms of a few well?defined parameters and expressed as a recirculation matrix. The implementation of a few heat?transfer relations suitable for high-temperature gas-cooled reactors allows for the rapid estimation of thermal properties critical for safe operation. Thus, modeling and design optimization of a given pebble-bed core can be performed quickly and efficiently via the manipulation of a limited number key parameters. Automation of the optimization process is achieved by manipulation of these parameters using a genetic algorithm. The end result is an economical, passively safe, proliferation-resistant nuclear power plant.

Experimental investigations on friction laws and dryout heat flux of particulate beds packed with multi-size spheres and irregular particles

International Nuclear Information System (INIS)

Li, Liangxing; Ma, Weimin

2011-01-01

This paper is concerned with reducing uncertainty in quantification of debris bed coolability in a hypothetical severe accident of light water reactors (LWRs). A test facility named POMECO-FL is constructed to investigate the friction laws of adiabatic single and two-phase flow in a particulate bed packed with multi-size spheres or irregular particles. The same types of particles were then loaded in the test section of the POMECO-HT facility to obtain the dryout heat flux of the volumetrically heated particulate bed. The POMECO-HT facility features a high power capacity (up to 2.1 MW/m 2 ) which enables coolability study on particulate bed with broad variations in porosity and particle diameters under both top-flooding and bottom-injection conditions. The results show that given the effective particle diameter obtained from single-phase flow through the packed bed with multi-size spheres or irregular particles, both the pressure drop and the dryout heat flux of two-phase flow through the bed can be predicted by the Reed model. The bottom injection of coolant increases the dryout heat flux significantly. Meanwhile, the elevation of the dryout position is moving upwards with increasing bottom-injection flowrate. The experimental data provides insights for interpretation of debris bed coolability, as well as high-quality data for validation of the coolability analysis models and codes. (author)

Effect of bed configuration on pebble flow uniformity and stagnation in the pebble bed reactor

International Nuclear Information System (INIS)

Gui, Nan; Yang, Xingtuan; Tu, Jiyuan; Jiang, Shengyao

2014-01-01

Highlights: • Pebble flow uniformity and stagnation characteristics are very important for HTR-PM. • Arc- and brachistochrone-shaped configuration effects are studied by DEM simulation. • Best bed configurations with uniform flow and no stagnated pebbles are suggested. • Detailed quantified characteristics of bed configuration effects are shown for explanation. - Abstract: Pebble flow uniformity and stagnation characteristics are very important for the design of pebble bed high temperature gas-cooled reactor. Pebble flows inside some specifically designed contraction configurations of pebble bed are studied by discrete element method. The results show the characteristics of stagnation rates, recycling rates, radial distribution of pebble velocity and residence time. It is demonstrated clearly that the bed with a brachistochrone-shaped configuration achieves optimum levels of flow uniformity and recycling rate concentration, and almost no pebbles are stagnated in the bed. Moreover, the optimum choice among the arc-shaped bed configurations is demonstrated too. Detailed information shows the quantified characteristics of bed configuration effects on flow uniformity. In addition, a good design of the pebble bed configuration is suggested

Visualization of bed material movement in a simulated fluidized bed heat exchanger by neutron radiography

International Nuclear Information System (INIS)

Umekawa, Hisashi; Ozawa, Mamoru; Takenaka, Nobuyuki; Matsubayashi, Masahito

1999-01-01

The bulk movement of fluidized bed material was visualized by neutron radiography by introducing tracers into the bed materials. The simulated fluidized bed consisted of aluminum plates, and the bed material was sand of 99.7% SiO 2 (mean diameter: 0.218 mm, density: 2555 kg/m 3 ). Both materials were almost transparent to neutrons. Then the sand was colored by the contamination of the sand coated by CdSO 4 . Tracer particles of about 2 mm diameter were made by the B 4 C, bonded by the vinyl resin. The tracer was about ten times as large as the particle of fluidized bed material, but the traceability was enough to observe the bed-material bulk movement owing to the large effective viscosity of the fluidized bed. The visualized images indicated that the bubbles and/or wakes were important mechanism of the behavior of the fluidized bed movement

Use of diffusive optical fibers for plant lighting

Energy Technology Data Exchange (ETDEWEB)

Kozai, T.; Kitaya, Y.; Fujiwara, K. [Chiba Univ., Matsudo (Japan); Kino, S.; Kinowaki, M. [Topy Green Ltd., Tokyo (Japan)

1994-12-31

Lighting is one of the most critical aspects in plant production and environmental research with plants. Much research has been repeated on the effect of light intensity, spectral distribution of light and lighting cycle, but comparatively little research done on the effect of lighting direction on the growth, development and morphology of plants. When plants are grown with lamps above, light is directed downward to the plants. Downward or overhead lighting is utilized in almost all cases. However, downward lighting does not always give the best result in terms of lighting efficiency, growth, development and morphology of plants. Kitaya et al. (1988) developed a lighting system in which two rooting beds were arranged; one above and the other under fluorescent lamps. Lettuce plants grew normally in the lower bed and suspended upside-down under the upper bed. The lettuce plants suspended upside-down were given the light in upward direction (upward lighting). No significant difference in growth, development and morphology was found between the lettuce plants grown by the downward and upward lighting. Combining upward and downward lighting, improved spacing efficiency and reduced electricity cost per plant compared with conventional, downward lighting. From the above example, when designing a lighting system for plants with lamps more lighting direction should be considered. In the present study, a sideward lighting system was developed using diffusive optical fiber belts. More higher quality tissue-cultured transplants could be produced in reduced space with sideward lighting system than with a downward lighting system. An application of the sideward lighting system using diffusive optical fiber belts is described and advantages and disadvantages are discussed.

Fluidised bed combustion system

International Nuclear Information System (INIS)

McKenzie, E.C.

1976-01-01

Fluidized bed combustion systems that facilitates the maintenance of the depth of the bed are described. A discharge pipe projects upwardly into the bed so that bed material can flow into its upper end and escape downwardly. The end of the pipe is surrounded by an enclosure and air is discharged into the enclosure so that material will enter the pipe from within the enclosure and have been cooled in the enclosure by the air discharged into it. The walls of the enclosure may themselves be cooled

WTP Pretreatment Facility Potential Design Deficiencies--Sliding Bed and Sliding Bed Erosion Assessment

Energy Technology Data Exchange (ETDEWEB)

Hansen, E. K. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

2015-05-06

This assessment is based on readily available literature and discusses both Newtonian and non-Newtonian slurries with respect to sliding beds and erosion due to sliding beds. This report does not quantify the size of the sliding beds or erosion rates due to sliding beds, but only assesses if they could be present. This assessment addresses process pipelines in the Pretreatment (PT) facility and the high level waste (HLW) transfer lines leaving the PT facility to the HLW vitrification facility concentrate receipt vessel.

WTP Pretreatment Facility Potential Design Deficiencies--Sliding Bed and Sliding Bed Erosion Assessment

International Nuclear Information System (INIS)

Hansen, E. K.

2015-01-01

This assessment is based on readily available literature and discusses both Newtonian and non-Newtonian slurries with respect to sliding beds and erosion due to sliding beds. This report does not quantify the size of the sliding beds or erosion rates due to sliding beds, but only assesses if they could be present. This assessment addresses process pipelines in the Pretreatment (PT) facility and the high level waste (HLW) transfer lines leaving the PT facility to the HLW vitrification facility concentrate receipt vessel.

Experimental results of combustion and desulphurization in fluidized bed. Implementation opportunities

International Nuclear Information System (INIS)

Dragos, L.; Jinescu, G.; Scarlat, N.

1996-01-01

Possibilities of both stationary fluidized bed combustion (SFBC) and circulating fluidized bed combustion (CFBC) technologies for desulfurization of Romanian coal-fired power plants have been studied since the 70's. The results of research on a 2 MWh SFBC semi-industrial pilot hot water boiler and an 1 MWh CFBC pilot plant are presented. 4 sorts of lignite (3 Romanian and 1 Albanian) are used in the study. The combustion efficiencies for SFBC are between 82 - 84% and for CFBC - between 84 - 87%. The heat transfer coefficients for lignite and peat coal have been determined for different zones, different levels of ash recirculation rate and various operating loads. Experiments with 2 sorts of sorbents: dolomite and limestone, under different temperature conditions and at Ca/S molar ratio 0.5 - 3.5 have been carried out. The temperature range for the maximum values of desulfurization efficiency is 840-870 o C for limestone and 820-860 o C for dolomite. The following efficiency values are obtained for lignite in the SFBC pilot plant: 1) over 80%, when using dolomite as a sorbent and the Ca/S molar ratio is greater than 2.5; 2) 75 - 90%, when limestone has been used and the Ca/S molar ratio is in the range 2-3. Desulfurization efficiency in CFBC plant for lignite using limestone is 80-93% for Ca/S ratio between 2 and 3. The necessity to commission a demonstrative installation with low pollutant emissions is pointed out. The Comanesti Power Plant has been chosen for this purpose. An old 75 t/h steam boiler will be replaced with 45 MWh CFBC boiler for combined heat and steam production. The overall estimated investment costs for this plant are about 6 million $US. 1 tabs., 5 refs

Bacillus cereus in free-stall bedding.

Science.gov (United States)

Magnusson, M; Svensson, B; Kolstrup, C; Christiansson, A

2007-12-01

To increase the understanding of how different factors affect the bacterial growth in deep sawdust beds for dairy cattle, the microbiological status of Bacillus cereus and coliforms in deep sawdust-bedded free stalls was investigated over two 14-d periods on one farm. High counts of B. cereus and coliforms were found in the entire beds. On average, 4.1 log(10) B. cereus spores, 5.5 log(10) B. cereus, and 6.7 log(10) coliforms per gram of bedding could be found in the upper layers of the sawdust likely to be in contact with the cows' udders. The highest counts of B. cereus spores, B. cereus, and coliforms were found in the bedding before fresh bedding was added, and the lowest immediately afterwards. Different factors of importance for the growth of B. cereus in the bedding material were explored in laboratory tests. These were found to be the type of bedding, pH, and the type and availability of nutrients. Alternative bedding material such as peat and mixtures of peat and sawdust inhibited the bacterial growth of B. cereus. The extent of growth of B. cereus in the sawdust was increased in a dose-dependent manner by the availability of feces. Urine added to different bedding material raised the pH and also led to bacterial growth of B. cereus in the peat. In sawdust, a dry matter content greater than 70% was needed to lower the water activity to 0.95, which is needed to inhibit the growth of B. cereus. In an attempt to reduce the bacterial growth of B. cereus and coliforms in deep sawdust beds on the farm, the effect of giving bedding daily or a full replacement of the beds was studied. The spore count of B. cereus in the back part of the free stalls before fresh bedding was added was 0.9 log units lower in stalls given daily bedding than in stalls given bedding twice weekly. No effect on coliform counts was found. Replacement of the entire sawdust bedding had an effect for a short period, but by 1 to 2 mo after replacement, the counts of B. cereus spores in the

Chemical Oxygen Demand abatement in sewage using Micro-Aeration Enhanced Ecological Floating Bed

Science.gov (United States)

Shi, Hongle; Zhou, Gaofeng; Liu, Yiqing; Tan, Jiancong; Fu, Yongsheng

2018-02-01

The traditional ecological floating bed combined with micro-aeration system and artificial medium was developed for the removal of contaminants and remediation of surface water. This micro-aeration enhanced ecological floating bed (MAEEFB) consisted of aeration unit, microbial processing unit and aquatic plant unit. Batch experiments were conducted in different operating conditions on the removal of chemical oxygen demand (COD) in the sewage using MAEEFB. The removal rate of COD by MAEEFB, enhanced ecological floating bed (EEFB) and traditional ecological floating bed (TEFB) in the same reaction conditions was 59.2%, 56.9% and 30.6%, respectively, indicating that the combination of micro-aeration system and artificial medium could enhance the removal efficiency of COD in TEFB. In MAEEFB, the aeration intensity should be designed reasonablely considering both treatment efficiency and operation cost. Only increasing the specific surface area of the packing cannot effectively improve the purification efficiency of water. Factors like packing material, ability of intercepting organics and complicated extent of microorganisms attaching on the packing should also be considered.

Astronomical cycle origin of bedded chert: A middle Triassic bedded chert sequence, Inuyama, Japan

Science.gov (United States)

Ikeda, Masayuki; Tada, Ryuji; Sakuma, Hironobu

2010-09-01

Astronomical forcing is one of the main drivers of climate change, and astronomical cyclicity recorded in sediments provides a clue to understand the dynamics of the global climate system. Bedded cherts consist of rhythmic alternations of chert and shale beds. Although previous studies have hypothesized that the origin of bedded chert is related to astronomical cycles (e.g. Fischer, 1976; Hori et al., 1993), conclusive proof remains elusive. To explore this possibility, we established a continuous, high-resolution lithostratigraphy of middle Triassic bedded chert in Central Japan. The average duration of each chert-shale couplet is 20 kyr, similar to that of the precession cycle. Spectral analysis of a bed number series of thickness variations in chert beds was performed assuming that each chert-shale couplet represents a 20-kyr precession cycle. The results reveal cycles involving approximately 200, 20, 5, and 2-3 beds, corresponding to periodicities of approximately 4000, 400, 100, and 40-60 kyr, respectively. By further assuming that the 20-bed cycle represents a 405-kyr eccentricity cycle of constant and stable periodicity, we converted the bed number series to a time series. Spectral analysis of the time series revealed distinct periodicities of 3600, 117, 97, and 38 kyr, in addition to 405 kyr. Besides 3600 kyr, these periodicities agree well with the 120, 95, and 37 kyr periodicities for eccentricity cycles and the obliquity cycle during the Triassic. Moreover, we detected amplitude modulation of the approximately 100-kyr cycle of thickness variations in chert beds with a 405-kyr periodicity, which may correspond to amplitude modulation of 100-kyr climatic precession cycle with the 405-kyr periodicity. The approximately 3600-kyr periodicity described above and 1800-kyr periodicity manifested as the amplitude modulation of the 405-kyr cycle are correlated to present-day long-term eccentricity cycles of 2400 and 4800 kyr evolved by chaotic behavior of solar

The exploitation of swamp plants for dewatering liquid sewage sludge

Directory of Open Access Journals (Sweden)

Jiří Šálek

2006-01-01

Full Text Available The operators of little rural wastewater treatment plants have been interested in economic exploitation of sewage sludge in local conditions. The chance is searching simply and natural ways of processing and exploitation stabilized sewage sludge in agriculture. Manure substrate have been obtained by composting waterless sewage sludge including rest plant biomass after closing 6–8 years period of filling liquid sewage sludge to the basin. Main attention was focused on exploitation of swamp plants for dewatering liquid sewage sludge and determination of influence sewage sludge on plants, intensity and course of evapotranspiration and design and setting of drying beds. On the base of determined ability of swamp plants evapotranspiration were edited suggestion solutions of design and operation sludge bed facilities in the conditions of small rural wastewater treatment plant.

Pyrolysis of rubber gloves in integral pyrolysis test plant

International Nuclear Information System (INIS)

Norasalwa Zakaria; Mohd Noor Muhd Yunus; Mohd Annuar Assadat Husain; Farid Nasir Ani

2010-01-01

Previously, pyrolysis of rubber gloves in laboratory study was described. In order to visualize the practical application of rubber gloves pyrolysis in terms of treating rubber gloves in medical waste, a new test plant was designed and constructed. The semi-continuous test plant was designed to accommodate rubber gloves that were not cut or shredded. The test plant has a capacity of 2kg/ hr and employed auxiliary fuel instead of the conventional electrical power for heating. The concept was based on moving bed reactor, but additional feature of sand jacket feature was also introduced in the design. Pyrolysis of the gloves was conducted at three temperatures, namely 350 degree Celsius, 400 degree Celsius and 450 degree Celsius. Oxygen presents inside of the reactor due to the combined effect of imperfect sealing and suction effect. This study addresses the performance of this test plant covering the time temperature profile, gas evolution profile and product yield. Comparison between the yield of the liquid, gas and char pyrolyzate was made against the laboratory study. It was found that the oil yield was less than the one obtained from bench scale study. Water formation was more pronounced. The presence of the oxygen also altered the tail gas composition but eliminate the sticky nature of solid residue, making it easier to handle. The chemical composition of the oil was determined and the main compounds in the oil were esters and phtalic acid. (author)

Characteristics of convective heat transport in a packed pebble-bed reactor

Energy Technology Data Exchange (ETDEWEB)

Abdulmohsin, Rahman S., E-mail: rsar62@mst.edu [Department of Chemical and Biochemical Engineering, Missouri University of Science and Technology, 400 West 11th Street/231 Schrenk Hall, Rolla, MO 65409-1230 (United States); Al-Dahhan, Muthanna H., E-mail: aldahhanm@mst.edu [Department of Chemical and Biochemical Engineering, Missouri University of Science and Technology, 400 West 11th Street/231 Schrenk Hall, Rolla, MO 65409-1230 (United States); Department of Nuclear Engineering, 301 W. 14th St./222 Fulton Hall (United States)

2015-04-01

Highlights: • A fast-response heat transfer probe has been developed and used in this work. • Heat transport has been quantified in terms of local heat transfer coefficients. • The method of the electrically heated single sphere in packing has been applied. • The heat transfer coefficient increases from the center to the wall of packed bed. • This work advancing the knowledge of heat transport in the studied packed bed. - Abstract: Obtaining more precise results and a better understanding of the heat transport mechanism in the dynamic core of packed pebble-bed reactors is needed because this mechanism poses extreme challenges to the reliable design and efficient operation of these reactors. This mechanism can be quantified in terms of a solid-to-gas convective heat transfer coefficient. Therefore, in this work, the local convective heat transfer coefficients and their radial profiles were measured experimentally in a separate effect pilot-plant scale and cold-flow experimental setup of 0.3 m in diameter, using a sophisticated noninvasive heat transfer probe of spherical type. The effect of gas velocity on the heat transfer coefficient was investigated over a wide range of Reynolds numbers of practical importance. The experimental investigations of this work include various radial locations along the height of the bed. It was found that an increase in coolant gas flow velocity causes an increase in the heat transfer coefficient and that effect of the gas flow rate varies from laminar to turbulent flow regimes at all radial positions of the studied packed pebble-bed reactor. The results show that the local heat transfer coefficient increases from the bed center to the wall due to the change in the bed structure, and hence, in the flow pattern of the coolant gas. The findings clearly indicate that one value of an overall heat transfer coefficient cannot represent the local heat transfer coefficients within the bed; therefore, correlations are needed to

Seepage patterns of Diuron in a ditch bed during a sequence of flood events

International Nuclear Information System (INIS)

Dages, C.; Samouëlian, A.; Negro, S.; Storck, V.; Huttel, O.; Voltz, M.

2015-01-01

Although ditches limit surface water contamination, groundwater recharge through ditches in Mediterranean catchments may result in groundwater contamination. We analysed the dynamics of pesticide percolation in ditches by conducting an original lab experiment that mimicked the successive percolation processes that occur during a flood season. Nine successive percolation events were operated on an undisturbed soil column collected from a ditch bed. The infiltrating water was doped with 14 C-Diuron at concentrations that were chosen to decrease between the events so as to correspond to values observed during actual flood events. The water and solute fluxes were monitored during each event, and the final extractable and non-extractable Diuron residues in the column were determined. Two main observations were made. First, a high leaching potential was observed through the ditch bed over a succession of infiltrating flood events, with 58.9% of the infiltrated Diuron and its metabolites leaching. Second, compared with the contamination of surface water circulating in the ditches, the contamination of seepage water exhibited smaller peak values and persisted much longer because of the desorption of Diuron residues stored in the ditch bed. Thus, ditches serve as buffering zones between surface and groundwater. However, compared with field plots, ditches appear to be a preferential location for the percolation of pesticides into groundwater at the catchment scale. - Highlights: • Diuron percolation in a ditch bed during flood events was mimicked in a column setup. • Diuron percolation can represent up to 50% of the infiltrated Diuron. • The ditch bed exhibits a high buffering capacity due to its high sorption properties. • Contamination period of percolation water lasts longer than that of infiltrating water. • Diuron residues stored in ditch bed move deeper than in field topsoils.

Seepage patterns of Diuron in a ditch bed during a sequence of flood events

Energy Technology Data Exchange (ETDEWEB)

Dages, C., E-mail: cecile.dages@supagro.inra.fr; Samouëlian, A.; Negro, S.; Storck, V.; Huttel, O.; Voltz, M.

2015-12-15

Although ditches limit surface water contamination, groundwater recharge through ditches in Mediterranean catchments may result in groundwater contamination. We analysed the dynamics of pesticide percolation in ditches by conducting an original lab experiment that mimicked the successive percolation processes that occur during a flood season. Nine successive percolation events were operated on an undisturbed soil column collected from a ditch bed. The infiltrating water was doped with {sup 14}C-Diuron at concentrations that were chosen to decrease between the events so as to correspond to values observed during actual flood events. The water and solute fluxes were monitored during each event, and the final extractable and non-extractable Diuron residues in the column were determined. Two main observations were made. First, a high leaching potential was observed through the ditch bed over a succession of infiltrating flood events, with 58.9% of the infiltrated Diuron and its metabolites leaching. Second, compared with the contamination of surface water circulating in the ditches, the contamination of seepage water exhibited smaller peak values and persisted much longer because of the desorption of Diuron residues stored in the ditch bed. Thus, ditches serve as buffering zones between surface and groundwater. However, compared with field plots, ditches appear to be a preferential location for the percolation of pesticides into groundwater at the catchment scale. - Highlights: • Diuron percolation in a ditch bed during flood events was mimicked in a column setup. • Diuron percolation can represent up to 50% of the infiltrated Diuron. • The ditch bed exhibits a high buffering capacity due to its high sorption properties. • Contamination period of percolation water lasts longer than that of infiltrating water. • Diuron residues stored in ditch bed move deeper than in field topsoils.

FY 1989 report on the results of the development of the entrained bed coal gasification power plant. Part 2. Fabrication/installation of pilot plant; 1989 nendo seika hokokusho. Funryusho sekitan gaska hatsuden plant kaihatsu - Sono 2. Pilot plant seisaku suetsuke hen

Energy Technology Data Exchange (ETDEWEB)

NONE

1990-03-01

For the purpose of establishing the technology of the integrated coal gasification combined cycle power generation, the fabrication, installation work, etc. were conducted of a 200t/d entrained bed coal gasification pilot plant, and the FY 1989 results were summarized. As to the gasifier equipment, fabrication of a considerable number of the main equipment was finished. And, the equipment was sent into the coal gasification power plant and the installation work was done. Concerning gas refining facilities, fabrication of most of the components of the dry desulfurization system was finished, and further, fabrication of part of the piping prefabrication, disk and part of the disk fitting instrument was finished. The partial equipment of the dry dust removal system was also fabricated. About gas turbine facilities, the drawings necessary for each of the equipment fabricated/installed in this fiscal year were made, and at the same time a part of the technical data prepared so far was reviewed according to the progress of design. As to safety environmental facilities, installation work was done of gas treatment furnace, gas cooling system, buffer tank, desulfurizing tower, etc. Besides, design/technical study were made of the total control system, equipment of the indoor switching station, etc. (NEDO)

Performance of a full-scale ITER metal hydride storage bed in comparison with requirements

International Nuclear Information System (INIS)

Beloglazov, S.; Glugla, M.; Fanghaenel, E.; Perevezentsev, A.; Wagner, R.

2008-01-01

The storage of hydrogen isotopes as metal hydride is the technique chosen for the ITER Tritium Plant Storage and Delivery System (SDS). A prototype storage bed of a full-scale has been designed, manufactured and intensively tested at the Tritium Laboratory, addressing main performance parameters specified for the ITER application. The main requirements for the hydrogen storage bed are a strict physical limitation of the tritium storage capacity (currently 70 g T 2 ), a high supply flow rate of hydrogen isotopes, in-situ calorimetry capabilities with an accuracy of 1 g and a fully tritium compatible design. The pressure composition isotherm of the ZrCo hydrogen system, as a reference material for ITER, is characterised by significant slope. As a result technical implementation of the ZrCo hydride bed in the SDS system requires further considerations. The paper presents the experience from the operation of ZrCo getter bed including loading/de-loading operation, calorimetric loop performance, and active gas cooling of the bed for fast absorption operation. The implications of hydride material characteristics on the SDS system configuration and design are discussed. (authors)

Heat transfer to immersed horizontal tubes in gas fluidized bed dryers

Energy Technology Data Exchange (ETDEWEB)

Jonassen, Ola

1999-10-01

The main objective of this study was to construct heat pump fluidized bed dryers of the FHT type with improved dewatering capacity for a given size of the dryer. The use of heat exchangers immersed in the fluidized bed drying chambers is an important part of the FHT (Fluidized Bed High Temperature Heat Pump Dryer) concept. A pilot plant FHT dryer was built and successfully tested on fish meal raw material and seaweed. The plant included two fluidized bed drying chambers with immersed heat exchangers. The gain in water vapor of the drying air through the chambers was increased up to four times that of adiabatic drying. The energy saving concept was retained as a SMER ratio of 3.5 to 4.7 was measured in the same tests. Therefore optimization of the immersed heat exchangers was considered the most important single objective for this work. The optimization study of the heat exchangers was confined to the actual operating conditions for the dryers using: (1) Bubbling gas fluidized beds were used, (2) air as the only type of fluidising gas, (3) beds at atmospheric pressure, (4) bed temperatures below 100 {sup o}C, (5) fluidized particles of Geldart classes B and D, (6) horizontal tube banks for the immersed heat exchanger, and the influence of radiation heat transfer was ignored. The heat transfer study was confined to the fluidized bed side of the heat exchanger surface. It was concluded early in this work that the bubbles play a major role in generating the particle circulation inside the bed and hence also in heat transfer. Publications describing the most important bubble induced mechanisms contributing to high rates of heat transfer were found to be limited. Therefore the first part of this study was aimed at establishing a method for locating and measuring the size and rise velocity of bubbles inside the bed. The method established through this work using differential pressure measurements from two static pressure probes was used later in the study of heat transfer

Radioactive-waste isolation pilot plant

International Nuclear Information System (INIS)

Weart, W.D.

1977-01-01

The objective of the Waste Isolation Pilot Plant (WIPP) program is to demonstrate the suitability of bedded salt, specifically, the bedded salt deposits in the Los Medanos area of southeastern New Mexico, as a disposal medium for radioactive wastes. Our program responsibilities include site selection considerations, all aspects of design and development, technical guidance of facility operation, environmental impact assessment, and technical support to ERDA for developing public understanding of the facility

Mapping Sargassum beds off, ChonBuri Province, Thailand, using ALOS AVNI2 image

Science.gov (United States)

Noiraksar, Thidarat; Komatsu, Teruhisa; Sawayama, Shuhei; Phauk, Sophany; Hayashizaki, Ken-ichi

2012-10-01

Sargassum species grow on rocks and dead corals and form dense seaweed beds. Sargassum beds play ecological roles such as CO2 uptake and O2 production through photosynthesis, spawning and nursery grounds of fish, feeding ground for sea urchins and abalones, and substrates for attached animals and plants on leaves and holdfasts. However, increasing human impacts and climate change decrease or degrade Sargassum beds in ASEAN countries. It is necessary to grasp present spatial distributions of this habitat. Thailand, especially its coastal zone along the Gulf of Thailand, is facing degradation of Sargassum beds due to increase in industries and population. JAXA launched non-commercial satellite, ALOS, providing multiband images with ultra-high spatial resolution optical sensors (10 m), AVNIR2. Unfortunately, ALOS has terminated its mission in April 2011. However, JAXA has archived ALOS AVNIR2 images over the world. They are still useful for mapping coastal ecosystems. We examined capability of remote sensing with ALOS AVNIR2 to map Sargassum beds in waters off Sattahip protected area as a natural park in Chon Buri Province, Thailand, threatened by degradation of water quality due to above-mentioned impacts. Ground truth data were obtained in February 2012 by using continual pictures taken by manta tow. Supervised classification could detect Sargassum beds off Sattahip at about 70% user accuracy. It is estimated that error is caused by mixel effect of bottom substrates in a pixel with 10 x 10 m. Our results indicate that ALOS AVNIR2 images are useful for mapping Sargassum beds in Southeast Asia.

Biomass fueled fluidized bed combustion: atmospheric emissions, emission control devices and environmental regulations

International Nuclear Information System (INIS)

Grass, S.W.; Jenkins, B.M.

1994-01-01

Fluidized bed combustors have become the technological choice for power generation from biomass fuels in California. Atmospheric emission data obtained during compliance tests are compared for five operating 18 to 32 MW fluidized bed combustion power plants. The discussion focuses on the impact of fuel properties and boiler design criteria on the emission of pollutants, the efficiency of pollution control devices, and regulations affecting atmospheric emissions. Stack NO x emission factors are shown not to vary substantially among the five plants which burn fuels with nitrogen concentrations between 0.3 and 1.1% dry weight. All facilities use at least one particular control device, but not all use limestone injection or other control techniques for sulfur and chlorine. The lack of control for chlorine suggests the potential for emission of toxic species due to favorable temperature conditions existing in the particulate control devices, particularly when burning fuels containing high concentrations of chlorine. (Author)

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).

Bed and bed-site reuse by western lowland gorillas (Gorilla g. gorilla) in Moukalaba-Doudou National Park, Gabon.

Science.gov (United States)

Iwata, Yuji; Ando, Chieko

2007-01-01

In this paper we describe bed (nest) and bed-site reuse by western lowland gorillas (Gorilla g. gorilla) in Moukalaba-Doudou National Park, south-eastern Gabon. During an eight-month study 44 bed sites and 506 beds were found. Among these, 38.6% of bed sites and 4.1% of beds were reused. We analyzed the monthly frequency of bed-site reuse in relation to rainfall, fruit abundance, and fruit consumption by the gorillas. The different frequency of bed-site reuse in the rainy and dry seasons was not significant. More bed-site reuse was observed during the fruiting season than during the non-fruiting season. Results from fecal analysis suggested that gorillas ate more fruit in the fruiting season than in the non-fruiting season. The frugivorous diet of western gorillas may possibly cause gorillas to stay in some areas and, consequently, reuse their bed sites. Reuse of bed sites by gorillas suggests their frequent return to an area where preferred fruit is readily available. A higher percentage of arboreal beds may also affect bed-site reuse, because of the shortage of bed material.

Shihoro irradiation plant for potato

International Nuclear Information System (INIS)

Kameyama, Kenji

1985-01-01

There have been rapid moves toward the commercialization of food irradiation around the world since November, 1980, when a joint FAO/IAEA/WHO expert committee made a recommendation on the wholesomeness of irradiated foods. The bold US move toward the commercialization has had a great impact. Ahead of these move around the world, Japan built a commercial irradiation plant in 1974, which has been operated for inhibiting the sprouting of potatoes. This plant was built in Shihoro, Hokkaido, and two thirds of the 400 million yen construction cost was provided by the Government and Hokkaido authorities for five agricultural cooperative associations of four local townships. Since then, the plant has been under the joint management of these cooperatives. The aim and circumstance of the plant construction are described. The mechanism of the plant with conveyors, a turntable and a Co-60 source of 300,000 Ci is shown. The plant processes 15 tons of potatoes per hour with the dose from 60 to 150 Gy. Potato bruise and irradiation effect, irradiation time and effect, and post-irradiation storage temperature and potato quality are reported. (Kako, I.)

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.

The effect of vibration on bed voidage behaviors in fluidized beds with large particles

Directory of Open Access Journals (Sweden)

H. Jin

2007-09-01

Full Text Available The effects of vibration parameters, operating conditions and material properties on bed voidage were investigated using an optical fiber probe approach in a vibrating fluidized bed with a diameter of 148 mm. Variables studied included frequency (0-282 s-1, amplitude (0 mm-1 mm, bed height (0.1 m-0.4 m as well as four kinds of particles (belonging to Geldart's B and D groups. The axial and radial voidage distribution with vibration is compared with that without vibration, which shows vibration can aid in the fluidization behaviors of particles. For a larger vibration amplitude, the vibration seriously affects bed voidage. The vibration energy can damp out for particle layers with increasing the bed height. According to analysis of experimental data, an empirical correlation for predicting bed voidage, giving good agreement with the experimental data and a deviation within ±15%, was proposed.

The regeneration test of the secondary loop condensate polishing mixed bed resin in Qinshan NPP

International Nuclear Information System (INIS)

Xu Meijing; Dong Liming

1995-12-01

There are four condensate polishing mixed beds in the water chemical treatment plant of Qinshan NPP. 2125 kg of D001-TR type cation exchange resin, 2000 kg of D201-TR type anion exchange resin, and 375 kg of S-TR type inert resin are filled into each mixed bed. The bed height of resin is 1.2 m and the volume is about 2.7 m 3 . In order to regenerate the exhausted resin out of the bed, the pre-designed condensate polishing mixed bed regeneration process was used to regenerate the first exhausted resin. After the resin was scrubbed and separated, cation resin and anion resin were respectively regenerated, rinsed to resume the exchange capability of the resin. The regenerated mixed bed is able to keep higher efficiency for condensate polishing. The outlet water quality and the resin service-life are able to meet the design requirements or more favorable than that. During the test, some main cations and anions in the blow-off water at each procedure were analyzed. The analyzed results were used to make pre-designed regeneration process better. The test results proved that pre-designed process is reasonable and effective. (6 refs., 6 figs., 7 tabs.)

Deposition reactors for solar grade silicon: A comparative thermal analysis of a Siemens reactor and a fluidized bed reactor

Science.gov (United States)

Ramos, A.; Filtvedt, W. O.; Lindholm, D.; Ramachandran, P. A.; Rodríguez, A.; del Cañizo, C.

2015-12-01

Polysilicon production costs contribute approximately to 25-33% of the overall cost of the solar panels and a similar fraction of the total energy invested in their fabrication. Understanding the energy losses and the behaviour of process temperature is an essential requirement as one moves forward to design and build large scale polysilicon manufacturing plants. In this paper we present thermal models for two processes for poly production, viz., the Siemens process using trichlorosilane (TCS) as precursor and the fluid bed process using silane (monosilane, MS). We validate the models with some experimental measurements on prototype laboratory reactors relating the temperature profiles to product quality. A model sensitivity analysis is also performed, and the effects of some key parameters such as reactor wall emissivity and gas distributor temperature, on temperature distribution and product quality are examined. The information presented in this paper is useful for further understanding of the strengths and weaknesses of both deposition technologies, and will help in optimal temperature profiling of these systems aiming at lowering production costs without compromising the solar cell quality.

Microbial mechanisms of using enhanced ecological floating beds for eutrophic water improvement.

Science.gov (United States)

Wu, Qing; Hu, Yue; Li, Shuqun; Peng, Sen; Zhao, Huabing

2016-07-01

Enhanced ecological floating beds were implemented to reduce nutrient quantity and improve the water quality of a eutrophic lake. The results showed that average removal efficiencies of CODCr, total nitrogen, NH3-N and total phosphorus for Canna indica L. set-up were 23.1%, 15.3%, 18.1% and 19.4% higher, respectively, than that of the setup with only substrate, and 14.2%, 12.8%, 7.9% and 11.9% higher than Iris pseudacorus L. ecological floating bed. The microbial community structure had obvious differences between devices and low similarity; bacteria were mainly attached on the fiber filling. The microbial population was abundant at the start and end of the experiment. Shannon index of samples selected ranged from 0.85 to 1.05. The sequencing results showed that fiber filling collected most uncultured bacteria species and the majority of bacteria on the plant roots were β-Proteobacteria and α-Proteobacteria. The co-dominant species attaching to the filling and plant was Nitrosomonadaceae. Copyright © 2016 Elsevier Ltd. All rights reserved.

Loading and Unloading Weaned Pigs: Effects of Bedding Types, Ramp Angle, and Bedding Moisture

Directory of Open Access Journals (Sweden)

Arlene Garcia

2014-12-01

Full Text Available The use of non-slip surfaces during loading and unloading of weaned pigs plays an important role in animal welfare and economics of the pork industry. Currently, the guidelines available only suggest the use of ramps below 20° to load and unload pigs. Three ramp angles (0°, 10° or 20°, five bedding materials (nothing, sand, feed, wood shavings or wheat straw hay, two moistures (dry or wet bedding; >50% moisture over two seasons (>23.9 °C summer, <23.9 °C winter were assessed for slips/falls/vocalizations (n = 6,000 pig observations. “Score” was calculated by the sum of slips, falls, and vocalizations. With the exception of using feed as a bedding, all beddings provided some protection against elevated slips, falls, and vocalizations (P < 0.01. Providing bedding reduced (P < 0.05 scores regardless of whether the bedding was dry or wet. Scores increased as the slope increased (P < 0.01. Provision of bedding, other than feed, at slopes greater than zero, decreased slips, falls and vocalizations. The total time it took to load and unload pigs was

Environmental protection stability of river bed and banks using convex, concave, and linear bed sills.

Science.gov (United States)

Keshavarzi, Alireza; Noori, Lila Khaje

2010-12-01

River bed scourings are a major environmental problem for fish and aquatic habitat resources. In this study, to prevent river bed and banks from scouring, different types of bed sills including convex, concave and linear patterns were installed in a movable channel bed in a laboratory flume. The bed sills were tested with nine different arrangements and under different flow conditions. To find the most effective bed sill pattern, the scouring depth was measured downstream of the bed sill for a long experimental duration. The scour depth was measured at the middle and at the end of each experimental test for different ratios of the arch radius to the channel width [r/w]. The experimental results indicated that the convex pattern with r/w=0.35 produced minimum bed scouring depth at the center line whereas the concave pattern with r/w=0.23 produced the minimum scour depth at the wall banks. Therefore, the convex pattern was the most effective configuration for prevention of scouring at the center line of the river while the concave pattern was very effective to prevent scouring at the river banks. These findings can be suggested to be used in practical applications.

Plant automation

International Nuclear Information System (INIS)

Christensen, L.J.; Sackett, J.I.; Dayal, Y.; Wagner, W.K.

1989-01-01

This paper describes work at EBR-II in the development and demonstration of new control equipment and methods and associated schemes for plant prognosis, diagnosis, and automation. The development work has attracted the interest of other national laboratories, universities, and commercial companies. New initiatives include use of new control strategies, expert systems, advanced diagnostics, and operator displays. The unique opportunity offered by EBR-II is as a test bed where a total integrated approach to automatic reactor control can be directly tested under real power plant conditions

Integrated detoxification methodology of hazardous phenolic wastewaters in environmentally based trickle-bed reactors: Experimental investigation and CFD simulation

International Nuclear Information System (INIS)

Lopes, Rodrigo J.G.; Almeida, Teresa S.A.; Quinta-Ferreira, Rosa M.

2011-01-01

Centralized environmental regulations require the use of efficient detoxification technologies for the secure disposal of hazardous wastewaters. Guided by federal directives, existing plants need reengineering activities and careful analysis to improve their overall effectiveness and to become environmentally friendly. Here, we illustrate the application of an integrated methodology which encompasses the experimental investigation of catalytic wet air oxidation and CFD simulation of trickle-bed reactors. As long as trickle-bed reactors are determined by the flow environment coupled with chemical kinetics, first, on the optimization of prominent numerical solution parameters, the CFD model was validated with experimental data taken from a trickle bed pilot plant specifically designed for the catalytic wet oxidation of phenolic wastewaters. Second, several experimental and computational runs were carried out under unsteady-state operation to evaluate the dynamic performance addressing the TOC concentration and temperature profiles. CFD computations of total organic carbon conversion were found to agree better with experimental data at lower temperatures. Finally, the comparison of test data with simulation results demonstrated that this integrated framework was able to describe the mineralization of organic matter in trickle beds and the validated consequence model can be exploited to promote cleaner remediation technologies of contaminated waters.

Integrated detoxification methodology of hazardous phenolic wastewaters in environmentally based trickle-bed reactors: Experimental investigation and CFD simulation.

Science.gov (United States)

Lopes, Rodrigo J G; Almeida, Teresa S A; Quinta-Ferreira, Rosa M

2011-05-15

Centralized environmental regulations require the use of efficient detoxification technologies for the secure disposal of hazardous wastewaters. Guided by federal directives, existing plants need reengineering activities and careful analysis to improve their overall effectiveness and to become environmentally friendly. Here, we illustrate the application of an integrated methodology which encompasses the experimental investigation of catalytic wet air oxidation and CFD simulation of trickle-bed reactors. As long as trickle-bed reactors are determined by the flow environment coupled with chemical kinetics, first, on the optimization of prominent numerical solution parameters, the CFD model was validated with experimental data taken from a trickle bed pilot plant specifically designed for the catalytic wet oxidation of phenolic wastewaters. Second, several experimental and computational runs were carried out under unsteady-state operation to evaluate the dynamic performance addressing the TOC concentration and temperature profiles. CFD computations of total organic carbon conversion were found to agree better with experimental data at lower temperatures. Finally, the comparison of test data with simulation results demonstrated that this integrated framework was able to describe the mineralization of organic matter in trickle beds and the validated consequence model can be exploited to promote cleaner remediation technologies of contaminated waters. Copyright © 2011 Elsevier B.V. All rights reserved.

Fluidized bed and pulverized coal combustion residues for secondary pavements

International Nuclear Information System (INIS)

Ghafoori, N.; Diawara, H.; Wang, L.

2009-01-01

The United States produced nearly 125 million tons of coal combustion products in 2006. These by-products include fly ash, flue gas desulphurization materials, bottom ash, boiler slag, and other power plant by-products. The expense associated with waste disposal, lack of disposal sites, and significant environmental damage linked with the disposal of coal combustion residues have encouraged innovative utilization strategies such as the fluidized bed combustion (FBC) unit. This paper presented the results of a laboratory investigation that examined the properties of composites developed with different proportions of pre-conditioned FBC spent bed, pulverized coal combustion fly ash, natural fine aggregate, and Portland cement. The purpose of the study was to examine the extent to which the by-product composites could replace currently used materials in secondary roads. The paper presented the research objectives and experimental programs, including matrix constituent and proportions; mixture proportions; and mixing, curing, sampling, and testing. The discussion of results centered around compressive strength and expansion by internal sulfate attack. It was concluded that with proper proportioning, by-products of pulverized and fluidized bed combustion promote binding of sand particles and provide adequate strength under various curing and moisture conditions 4 refs., 6 tabs.

Biodiversity of seagrass bed in Balanan Resort - Baluran National Park

Science.gov (United States)

Soedarti, T.; Hariyanto, S.; Wedayanti, A.; Rahmawati, A. D.; Safitri, D. P.; Alificia, R. I.; Suwono

2017-09-01

Seagrass beds are flowering plants that live on the seabed. Seagrass provides a habitat for diverse flora and fauna, spawning ground, nursery ground, raising ground, and feeding ground. Balanan Resort - Baluran National Park has many beaches, such as Kajang Beach, Si Banjir Beach, Kakapa Beach, and Serondo Beach. This study was aimed to determine species composition, seagrass dominated, and the diversity index of seagrass and substrate in Resort Balanan - Baluran National Park. This research was carried out in Kajang Beach, Sibanjir Beach, Kakapa Beach, and Sirondo Beach from August to September 2015 using belt transect method, each transect consists of 15 plots (19 transects = 285 plots) and using the frame of 1x1 m. This research found seven genera and ten species : Cymodoce (C rotundata and C. serrulata), Syringodium (S. isoelifolium), Thallassodendron (T. ciliatum), Enhalus (E. acoroides) , Halodule (H. univernis and H. pinifolia), Halophila (H. ovalis and H. decipiens), and Thalassia (T. hemprichii). The diversity index of seagrass bed was moderate [H'=1.90] in Balanan Resort. The substrate of seagrass bed was mud, gravel, sand, clay sand and rubble in Balanan Resort. The dominance index was near zero [C = 0.194], that means no dominant species.

Dynamic Modeling and Control Studies of a Two-Stage Bubbling Fluidized Bed Adsorber-Reactor for Solid-Sorbent CO{sub 2} Capture

Energy Technology Data Exchange (ETDEWEB)

Modekurti, Srinivasarao; Bhattacharyya, Debangsu; Zitney, Stephen E.

2013-07-31

A one-dimensional, non-isothermal, pressure-driven dynamic model has been developed for a two-stage bubbling fluidized bed (BFB) adsorber-reactor for solid-sorbent carbon dioxide (CO{sub 2}) capture using Aspen Custom Modeler® (ACM). The BFB model for the flow of gas through a continuous phase of downward moving solids considers three regions: emulsion, bubble, and cloud-wake. Both the upper and lower reactor stages are of overflow-type configuration, i.e., the solids leave from the top of each stage. In addition, dynamic models have been developed for the downcomer that transfers solids between the stages and the exit hopper that removes solids from the bottom of the bed. The models of all auxiliary equipment such as valves and gas distributor have been integrated with the main model of the two-stage adsorber reactor. Using the developed dynamic model, the transient responses of various process variables such as CO{sub 2} capture rate and flue gas outlet temperatures have been studied by simulating typical disturbances such as change in the temperature, flowrate, and composition of the incoming flue gas from pulverized coal-fired power plants. In control studies, the performance of a proportional-integral-derivative (PID) controller, feedback-augmented feedforward controller, and linear model predictive controller (LMPC) are evaluated for maintaining the overall CO{sub 2} capture rate at a desired level in the face of typical disturbances.

Advanced waste water treatment in small sewage plants with less than 50 PE; Weitergehende Abwasserreinigung in biologischen Kleinklaeranlagen mit einem Anschluss < 50 EW

Energy Technology Data Exchange (ETDEWEB)

Peukert, V.

1999-12-31

In the course of a research and development project EvU {sup trademark} plc. has developed and tested a small sewage plant with biological phosphorus and nitrogen removal. This advanced treatment was carry out by the utilization of the activated sludge system combined with an aerob and respectively anoxic/anaerob moving bed biofilm system. Microorganisms with special metabolic efficiencies concentrate in a biofilm and settle down on cylindrical carriers. These carriers forms in dependence on the intensity of air introduction an ideally mixed turbulent or fluidized bed (aerob) and in areas without aeration an anoxic/anaerobic fluidized bed. By means of a special retention system the carrier material remains in the corresponding process stage without clogging. Using the technology mentioned above the purification efficiency concerning organic waste load and nitrogen does in no way lack behind that of modern large-sized sewage treatment plants. Phosphorus was eliminated 74% on average. The sludge production (excess sludge) could be decreased considerably. Investment and running cost as well as technological expenditures are comparable with sewage plants without advanced treatment. (orig.) [German] Im Rahmen des F/E-Vorhabens wurde eine Kleinklaeranlage mit biologischer Phosphor- und Stickstoffelimination entwickelt und getestet. Die weitergehende Abwasserreinigung wurde durch verfahrenstechnische Kopplung von Belebtschlammbiologie mit aerober und anoxisch-anaerober Biofilmbiologie erreicht. Dabei wurde ein Teil der Organismen in Form eines Biofilms auf frei beweglichen, zylindrischen Hohlkoerpern mit grosser Oberflaeche angesiedelt. Fuer die Rueckhaltung der Koerper im Wirbelbett wurde eine verstopfungsfreie Einrichtung entwickelt. Mit der Kleinklaeranlage wurden bei organischen Stoffen und Stickstoff unter paxisnahen Bedingungen die Mindestanforderungen von Grossklaeranlagen eingehalten. Phosphor wurde auf biologischem Wege im Mittel 74% eliminiert. Es wurde ein

Bedding and Fertilization Influence on Slash Pine Development in the Florida Sandhills

Science.gov (United States)

James B. Baker

1973-01-01

A field study on the infertile and droughty Lakeland sands of west Florida indicated that bedding or fertilization (134 kg P /ha as ordinary superphosphate and 90 kg N/ha as ammonium nitrate) or both increased early growth of planted slash pine ( Engelm.). Throughout the 6-year study, best growth was obtained when the treatments were...

Use of communication architecture test bed to evaluate data network performance

International Nuclear Information System (INIS)

Clapp, N.E. Jr.; Swail, B.K.; Naser, J.A.

1994-01-01

Local area networks (LANs) are becoming more prevalent in nuclear power plants. Traditionally, LANs were only used as information highways, providing office automation services. LANs are now being used as data highways for applications in plant data acquisition and control systems. A communication architecture test bed, which contains network simulators, is needed to allow network performance studies and to resolve design issues prior to equipment purchase. Two levels of granularity of simulation are needed to provide the dynamic information about network performance. A coarse-grain simulator is used to estimate the dynamic performance of the network due to major resources such as workstations, gateways, and data acquisition systems. A fine-grain simulator allows a greater level of detail about the underlying network protocol and resources to be simulated. The combination of coarse-grain and fine-grain simulation packages provides the network designer with the required tools to thoroughly understand the behavior of the modeled network. This paper describes the development of a communication architecture test bed using commercial network simulation packages. Network simulators allow the resolution of major design issues in software without the expense of purchasing costly hardware components

Flume Experiments on the Influence of Salmon Spawning Density on Grain Stability and Bedload Transport in Gravel-bed Streams

Science.gov (United States)

Buxton, T. H.

2015-12-01

Salmon spawning in streams involves the female salmon digging a pit in the bed where she deposits eggs for fertilization before covering them with gravel excavated from the next pit upstream. Sequences of pit excavation and filling winnow fines, loosen sediment, and move bed material into a tailspill mound resembling the shape of a dune. Research suggests salmonid nests (redds) destabilize streambeds by reducing friction between loosened grains and converging flow that elevates shear stress on redd topography. However, bed stability may be enhanced by form drag from redds in clusters that lower shear stress on the granular bed, but this effect will vary with the proportion of the bed surface that is occupied by redds (P). I used simulated redds and water-worked ("unspawned") beds in a laboratory flume to evaluate these competing influences on grain stability and bedload transport rates with P=0.12, 0.34, and 0.41. Results indicate that competence (largest-grain) and reference transport rate estimates of critical conditions for particle entrainment inversely relate to P. Bedload transport increased as exponential functions of P and excess boundary shear stress. Therefore, redd form drag did not overcome the destabilizing effects of spawning. Instead, grain mobility and bedload transport increased with P because larger areas of the bed were composed of relatively loose, unstable grains and redd topography that experienced elevated shear stress. Consequently, the presence of redds in fish-bearing streams likely reduces the effects of sedimentation from landscape disturbance on stream habitats that salmon use for reproduction.

Green and economical production of propionic acid by Propionibacterium freudenreichii CCTCC M207015 in plant fibrous-bed bioreactor.

Science.gov (United States)

Feng, Xiaohai; Chen, Fei; Xu, Hong; Wu, Bo; Li, Hui; Li, Sha; Ouyang, Pingkai

2011-05-01

Propionic acid production by Propionibacterium freudenreichii from molasses and waste propionibacterium cells was studied in plant fibrous-bed bioreactor (PFB). With non-treated molasses as carbon source, 12.69 ± 0.40 g l(-1) of propionic acid was attained at 120 h in free-cell fermentation, whereas the PFB fermentation yielded 41.22 ± 2.06 g l(-1) at 120 h and faster cells growth was observed. In order to optimize the fermentation outcomes, fed-batch fermentation was performed with hydrolyzed molasses in PFB, giving 91.89 ± 4.59 g l(-1) of propionic acid at 254 h. Further studies were carried out using hydrolyzed waste propionibacterium cells as substitute nitrogen source, resulting in a propionic acid concentration of 79.81 ± 3.99 g l(-1) at 302 h. The present study suggests that the low-cost molasses and waste propionibacterium cells can be utilized for the green and economical production of propionic acid by P. freudenreichii. Copyright © 2011 Elsevier Ltd. All rights reserved.

The effect of bed non-uniformities and porosity of particles on dryout in boiling particle beds

International Nuclear Information System (INIS)

Macbeth, R.V.; Mogford, D.J.; Willshire, S.J.

1988-03-01

This report relates to an on-going experimental programme concerned with the coolability of beds of reactor core debris or rubble immersed in a liquid coolant, as might occur in an accident situation. The objectives are to develop experimental techniques, improve the understanding of bed cooling mechanisms, determine dry-out limitations of various bed configurations and particle shapes and sizes and devise ways of improving bed coolability. The report concentrates on a recently discovered effect on bed coolability of particle porosity, such as exists in fragmented UO 2 fuel pellets. It is shown that porosity can lower bed dry-out powers by a factor of 4 or 5. A mechanism which explains the effect is presented. The report also gives results of bed non-uniformities obtained by mixing glass particles with the dielectrically heated 'ferrite' particles used in the experiments. (author)

Sustainable cotton production and water economy through different planting methods and mulching techniques

International Nuclear Information System (INIS)

Nasrullah, H.M.; Khan, M.B.; Ahmad, R.; Ahmad, S.; Hanif, M.; Nazeer, W

2011-01-01

Planting methods and mulching techniques are important factors which affect crop growth, development and yield by conserving soil and plant moisture. A multifactorial experiment was conducted to study the water economy involving different planting methods and mulching techniques in cotton (Gossypium hirsutum L.) for two consecutive years (2004 and 2005) at the Agronomic Research Station, Khanewal. Two moisture stress tolerant cotton varieties (CIM-473 and CIM-499) were planted using four different planting methods i.e. 70c m spaced single row planting, 105 cm spaced double row strip planting, 70 cm spaced ridge planting and 140 cm spaced furrow beds (or bed and furrows) along four mulching practices i.e. cultural, straw, sheet and chemical for their individual and interactive effects on various parameters including water use efficiency. Positive interactive effects of furrow bed planting method (140 cm spaced) with plastic sheet/film mulching were observed for all the parameters i.e., highest seed cotton yield (3009 and 3332 kg ha/sup -1/), maximum water saving (up to 25.62% and 26.53%), highest water use efficiency up to 5.04 and 4.79 [macro mol (CO/sub 2/)/mmol (H/sub 2/O)], highest net income (Rs. 27224.2 and 50927.7 ha/sup -1/) with a cost-benefit ratio of 1.64 and 2.20 followed by maximum net income (Rs. 27382.2 and 47244.5 ha/sup -1/) with 1.64 and 2.10 cost-benefit ratio in case of plastic mulch and 2814 and 3007 kg ha/sup -1/ in ridge planting method during 2004 and 2005, respectively. It is concluded that cotton crop can be grown using bed and furrow planting method with plastic sheet/film mulching technique for sustainable cotton production and better water economy. (author)

Measurements of trace contaminants in closed-type plant cultivation chambers

Science.gov (United States)

Tani, A.; Kiyota, M.; Aiga, I.; Nitta, K.; Tako, Y.; Ashida, A.; Otsubo, K.; Saito, T.

Trace contaminants generated in closed facilities can cause abnormal plant growth. We present measurement data of trace contaminants released from soils, plants, and construction materials. We mainly used two closed chambers, a Closed-type Plant and Mushroom Cultivation Chamber (PMCC) and Closed-type Plant Cultivation Equipment (CPCE). Although trace gas budgets from soils obtained in this experiment are only one example, the results indicate that the budgets of trace gases, as well as CO_2 and O_2, change greatly with the degree of soil maturation and are dependent on the kind of substances in the soil. Both in the PMCC and in the CPCE, trace gases such as dioctyl phthalate (DOP), dibutyl phthalate (DBP), toluene and xylene were detected. These gases seemed to be released from various materials used in the construction of these chambers. The degree of increase in these trace gas levels was dependent on the relationship between chamber capacity and plant quantity. Results of trace gas measurement in the PMCC, in which lettuce and shiitake mushroom were cultivated, showed that ethylene was released both from lettuce and from the mushroom culture bed. The release rates were about 90 ng bed^-1 h^-1 for the shiitake mushroom culture bed (volume is 1700 cm^3) and 4.1 ~ 17.3 ng dm^-2h^-1 (leaf area basis) for lettuce. Higher ethylene release rates per plant and per unit leaf area were observed in mature plants than in young plants.

Model-free adaptive control of advanced power plants

Science.gov (United States)

Cheng, George Shu-Xing; Mulkey, Steven L.; Wang, Qiang

2015-08-18

A novel 3-Input-3-Output (3.times.3) Model-Free Adaptive (MFA) controller with a set of artificial neural networks as part of the controller is introduced. A 3.times.3 MFA control system using the inventive 3.times.3 MFA controller is described to control key process variables including Power, Steam Throttle Pressure, and Steam Temperature of boiler-turbine-generator (BTG) units in conventional and advanced power plants. Those advanced power plants may comprise Once-Through Supercritical (OTSC) Boilers, Circulating Fluidized-Bed (CFB) Boilers, and Once-Through Supercritical Circulating Fluidized-Bed (OTSC CFB) Boilers.

Inductive classification of operating data from a fluidized bed calciner

International Nuclear Information System (INIS)

O'Brien, B.H.

1990-01-01

A process flowsheet expert system for a fluidized bed calciner which solidifies high-level radioactive liquid waste was developed from pilot-plant data using a commercial, inductive classification program. After initial classification of the data, the resulting rules were inspected and adjusted to match existing knowledge of process chemistry. The final expert system predicts performance of process flowsheets based upon the chemical composition of the calciner feed and has been successfully used to identify potential operational problems prior to calciner pilot-plant testing of new flowsheets and to provide starting parameters for pilot-plant tests. By using inductive classification techniques to develop the initial rules from the calciner pilot-plant data and using existing process knowledge to verify the accuracy of these rules, an effective expert system was developed with a minimum amount of effort. This method may be applied for developing expert systems for other processes where numerous operating data are available and only general process chemistry effects are known

The benefits of heavy resins in fluidized-bed ion-exchange columns

International Nuclear Information System (INIS)

Giddey, T.B.S.

1980-01-01

The advantages to be gained from the use of a high-density ion-exchange resin in a uranium-recovery circuit are shown. It is concluded that, in existing fluidized-bed plants, the throughput of solution can be increased by up to 40 per cent at the same uranium recovery. Alternatively, the values in the barren solution can be improved at the same flow-rate of solution [af

Effects of Different Corm Densities and Bed Types on Flower Yield Components of Saffron (Crocus sativus L.

Directory of Open Access Journals (Sweden)

A. Mollafilabi

2017-10-01

Full Text Available Introduction Saffron is among the most precious agricultural and medicinal plants of the world and has a specific placement in Iran exports. In Iran total cultivation area was 93000 ha in 2017 that from which about 96% devoted to two main provinces of saffron production including Khorasan-Razavi and South Khorasan with total production of 351 ton saffron. Saffron has unique characters including low water requirement, saffron irrigation in times that other crops do not need, farm utilization for some years, ease of transportation, lack of need to special machinery and complex technology, high capacity to use labor in time of picking flowers, occupation and in the end prevention from immigration and exchange income that make this crop becomes superior in those regions that lack of industrial perspectives and having water limitations. Organic fertilizers have effective role in saffron production including physical improvement of saffron soil, temperature relief, penetration improvement, porosity increase, and soil reducdtion in hardiness, and cause to saffron flowering. Several factors like climate, diseases, irrigation, storage, planting date, chemical and biological fertilizers and animal manure are very effective in saffron quantity and quality. Saffron yield depends on several factors like soil, crop density, planting method, corm size, geographical location, climatic factors like temperature fluctuations specially in time of flowering, rate of rainfall, cultural management and utilization period. The aim of this study was to determine possible effects of corm density and bed type on flower yield components and stigma yield of saffron. Materials and methods In order to evaluate effects of corm density and bed type on reproductive characters, yield components of flower and saffron stigma an experiment was conducted in the form of factorial as RCBD with three replicates at the research farm of Khorasan Science and Technology Part (KSTP during

Bed Bug Infestations and Control Practices in China: Implications for Fighting the Global Bed Bug Resurgence

Directory of Open Access Journals (Sweden)

Changlu Wang

2011-04-01

Full Text Available The bed bug resurgence in North America, Europe, and Australia has elicited interest in investigating the causes of the widespread and increasing infestations and in developing more effective control strategies. In order to extend global perspectives on bed bug management, we reviewed bed bug literature in China by searching five Chinese language electronic databases. We also conducted telephone interviews of 68 pest control firms in two cities during March 2011. In addition, we conducted telephone interviews to 68 pest control companies within two cities in March 2011. Two species of bed bugs (Cimex lectularius L. and Cimex hemipterus (F. are known to occur in China. These were common urban pests before the early1980s. Nationwide “Four-Pest Elimination” campaigns (bed bugs being one of the targeted pests were implemented in China from 1960 to the early 1980s. These campaigns succeeded in the elimination of bed bug infestations in most communities. Commonly used bed bug control methods included applications of hot water, sealing of bed bug harborages, physical removal, and applications of residual insecticides (mainly organophosphate sprays or dusts. Although international and domestic travel has increased rapidly in China over the past decade (2000–2010, there have only been sporadic new infestations reported in recent years. During 1999–2009, all documented bed bug infestations were found in group living facilities (military dormitories, worker dormitories, and prisons, hotels, or trains. One city (Shenzhen city near Hong Kong experienced significantly higher number of bed bug infestations. This city is characterized by a high concentration of migratory factory workers. Current bed bug control practices include educating residents, washing, reducing clutter, putting items under the hot sun in summer, and applying insecticides (pyrethroids or organophosphates. There have not been any studies or reports on bed bug insecticide

Identification of discontinuous sand pulses on the bed of the Colorado River in Grand Canyon

Science.gov (United States)

Mueller, E. R.; Grams, P. E.; Buscombe, D.; Topping, D. J.

2017-12-01

Decades of research on alluvial sandbars and sand transport on the Colorado River in Grand Canyon has contributed to in-depth understanding of the sand budget and lead to management actions designed to rebuild eroded sandbars. However, some basic, but difficult to address, questions about the processes and rates of sand movement through the system still limit our ability to predict geomorphic responses. The coarse fraction of the bed is heterogeneous and varies among boulders, cobble, gravel, and bedrock. Sand covers these substrates in patches of variable size and thickness, fills interstices to varying degrees, and forms mixed sand/coarse bed configurations such as linear stripes. Understanding the locations of sand accumulation, the quantities of sand contained in those locations, and the processes by which sand is exchanged among depositional locations is needed to predict the morphological response of sandbars to management actions, such as the controlled flood releases, and to predict whether sandbars are likely to increase or decrease in size over long (i.e. decadal) time periods. Here, we present evidence for the downstream translation of the sand component of tributary sediment inputs as discontinuous sand pulses. The silt and clay (mud) fraction of sediment introduced episodically by seasonal floods from tributary streams is transported entirely in suspension and moves through the 400 km series of canyons in a few days. The sand fraction of this sediment, which is transported on the bed and in suspension, moves downstream in sand pulses that we estimate range in length from a few km to tens of km. Owing to the complex geomorphic organization, the sand pulses are not detectable as coherent bed features; each individual sand pulse is comprised of many isolated storage locations, separated by rapids and riffles where sand cover is sparse. The presence of the sand pulses is inferred by the existence of alternating segments of sand accumulation and depletion

Seaweed beds support more juvenile reef fish than seagrass beds in a south-western Atlantic tropical seascape

Science.gov (United States)

Eggertsen, L.; Ferreira, C. E. L.; Fontoura, L.; Kautsky, N.; Gullström, M.; Berkström, C.

2017-09-01

Seascape connectivity is regarded essential for healthy reef fish communities in tropical shallow systems. A number of reef fish species use separate adult and nursery habitats, and hence contribute to nutrient and energy transfer between habitats. Seagrass beds and mangroves often constitute important nursery habitats, with high structural complexity and protection from predation. Here, we investigated if reef fish assemblages in the tropical south-western Atlantic demonstrate ontogenetic habitat connectivity and identify possible nurseries on three reef systems along the eastern Brazilian coast. Fish were surveyed in fore reef, back reef, Halodule wrightii seagrass beds and seaweed beds. Seagrass beds contained lower abundances and species richness of fish than expected, while Sargassum-dominated seaweed beds contained significantly more juveniles than all other habitats (average juvenile fish densities: 32.6 per 40 m2 in Sargassum beds, 11.2 per 40 m2 in back reef, 10.1 per 40 m2 in fore reef, and 5.04 per 40 m2 in seagrass beds), including several species that are found in the reef habitats as adults. Species that in other regions worldwide (e.g. the Caribbean) utilise seagrass beds as nursery habitats were here instead observed in Sargassum beds or back reef habitats. Coral cover was not correlated to adult fish distribution patterns; instead, type of turf was an important variable. Connectivity, and thus pathways of nutrient transfer, seems to function differently in east Brazil compared to many tropical regions. Sargassum-dominated beds might be more important as nurseries for a larger number of fish species than seagrass beds. Due to the low abundance of structurally complex seagrass beds we suggest that seaweed beds might influence adult reef fish abundances, being essential for several keystone species of reef fish in the tropical south-western Atlantic.

Investigation of heat transfer in bed and freeboard of fluidized bed combustors

International Nuclear Information System (INIS)

Mitor, V.V.; Matsnev, V.V.; Sorokin, A.P.

1986-01-01

Experimental results for heat transfer between immersed bundles of bare tubes and fluidized beds are reported. The experimental results are obtained on industrial boilers with a bed area from 2,5 to 4 m/sup 2/ under conditions of long term operation. The bed temperature range has been 1073 0 K-1233 0 K, gas velocity between 1,8-4,5 m/s, mean particle size from 1,5 mm to 6,0 mm, freeboard furnace height of 2,3 and 5 m. The obtained data are compared with experimental results from literature

Heat transfer to immersed horizontal tubes in gas fluidized bed dryers

Energy Technology Data Exchange (ETDEWEB)

Jonassen, Ola

1999-07-01

The main objective of this study was to construct heat pump fluidized bed dryers of the FHT type with improved dewatering capacity for a given size of the dryer. The use of heat exchangers immersed in the fluidized bed drying chambers is an important part of the FHT (Fluidized Bed High Temperature Heat Pump Dryer) concept. A pilot plant FHT dryer was built and successfully tested on fish meal raw material and seaweed. The plant included two fluidized bed drying chambers with immersed heat exchangers. The gain in water vapor of the drying air through the chambers was increased up to four times that of adiabatic drying. The energy saving concept was retained as a SMER ratio of 3.5 to 4.7 was measured in the same tests. Therefore optimization of the immersed heat exchangers was considered the most important single objective for this work. The optimization study of the heat exchangers was confined to the actual operating conditions for the dryers using: (1) Bubbling gas fluidized beds were used, (2) air as the only type of fluidizing gas,(3) beds at atmospheric pressure, (4) bed temperatures below 100 {sup o}C, (5) fluidized particles of Geldart classes B and D, (6) horizontal tube banks for the immersed heat exchanger and the influence of radiation heat transfer was ignored. The heat transfer study was confined to the fluidized bed side of the heat exchanger surface. It was concluded early in this work that the bubbles play a major role in generating the particle circulation inside the bed and hence also in heat transfer. Publications describing the most important bubble induced mechanisms contributing to high rates of heat transfer were found to be limited. Therefore the first part of this study was aimed at establishing a method for locating and measuring the size and rise velocity of bubbles inside the bed. The method established through this work using differential pressure measurements from two static pressure probes was used later in the study of heat transfer

Biodegradation of pharmaceuticals from hospital wastewater in staged Moving Bed Biofilm Reactors (MBBR)

DEFF Research Database (Denmark)

Escola, Monica; Kumar Chhetri, Ravi; Ooi, Gordon

2015-01-01

on biofilms that are grown on plastic-chips which are suspended and aerated in a treatment tank. Such biofilm systems have shown a clear (but slow) biodegradation of some compounds that are recalcitrant in activated sludge. This study investigated the performance of a pilot MBBR-plant for the removal...

Byssus attachment strength of two mytilids in mono-specific and mixed-species mussel beds.

Science.gov (United States)

Babarro, Jose M F; Comeau, Luc A

2014-09-01

The mussel Xenostrobus securis is endemic to the brackish waters of New Zealand and Australia, but has successfully invaded the inner Galician Rías of NW Spain, where it coexists with the indigenous mussel Mytilus galloprovincialis. In this laboratory study, the plasticity of the byssus attachment strength of two mytilids was compared by manipulating substratum, salinity, and bed assembly. M. galloprovincialis showed stronger byssus detachment strength than X. securis, despite lower byssus coverage. Both species responded similarly to the substratum, with substantially lower byssus strength on methacrylate, which offered the lowest surface free energy. Byssus detachment values for M. galloprovincialis were lower at lower salinity. In mixed beds, a number of mussels moved upwards, eventually colonising the upper layers of the assemblage. This behaviour increased byssus strength but only for X. securis. X. securis is adapted to a wide spectrum of abiotic conditions, a trait that may promote its dissemination within estuarine environments.

The Cross-Flow Mixing Analysis of Quasi-Static Pebble Flow in Pebble Bed Reactor

International Nuclear Information System (INIS)

Fang Xiang; Liu Zhiyong; Sun Yanfei; Yang Xingtuan; Jiang Shengyao

2014-01-01

In the pebble bed reactor, large number of fuel pebbles’ movement law and moving state can affect the reactor’s design, operation and safety directly. Therefore the pebble flow, which is based on the theory of particle streaming, is one of the most important research subjects of the pebble bed reactor engineering. The in-core pebble flow is a very slow particle flow (or called quasi-static particle flow), which is very different from the usual particle motion. How to accurately describe the characteristics of in-core pebble flow is a central issue for this subject. Due to the presence of random flow, the cross-mixing phenomenon will occur inevitably. In the present paper, the mixing phenomenon of pebble flow is generalized on the basis of experiment results. The pebble flow cross-mixing probability serves as the parameter which describes both the regularity and the randomness of pebble flow. The results are provided in the form of diagrammatic presentation. (author)

A moving finite element model of the high density z-pinch

International Nuclear Information System (INIS)

Glasser, A.H.

1989-01-01

This paper presents the results of computations of the behavior of the fiber-initiated high density Z-pinch (HDZP). It purpose is twofold. One is to study the behavior of the physical system itself as an interesting controlled fusion experiment. The main result of this study is a demonstration of the relaxation of the full inertial behavior of the pinch to simplified self-similar behavior in which the forces on the system are in near balance. The moving free boundary and violent initial behavior of this configuration require carful treatment. This leads to the other purpose of the work, to use this realistic physical system as a test-bed for a general-purpose 1-dimensional code based on moving finite elements. A key step in accomplishing this goal has been the recognition that numerical stability of the discretized equations has required the use of nonconservative quantities as the fundamental dependent variables to be discretized. The main result of this work is a code which is capable of treating a very general class of nonlinear, time-dependent fluid equations. copyright 1989 Academic Press, Inc

Improved lignin pyrolysis for phenolics production in a bubbling bed reactor--Effect of bed materials.

Science.gov (United States)

Li, Dongbing; Briens, Cedric; Berruti, Franco

2015-01-01

Lignin pyrolysis was studied in a bubbling fluidized bed reactor equipped with a fractional condensation train, using nitrogen as the fluidization gas. The effect of different bed materials (silica sand, lignin char, activated lignin char, birch bark char, and foamed glass beads) on bio-oil yield and quality was investigated for a pyrolysis temperature of 550 °C. Results how that a bed of activated lignin char is preferable to the commonly used silica sand: pyrolysis of Kraft lignin with a bed of activated lignin char not only provides a pure char product, but also a higher dry bio-oil yield (with a relative increase of 43%), lower pyrolytic water production, and better bio-oil quality. The bio-oil obtained from Kraft lignin pyrolysis with a bed of activated lignin char has a lower average molecular weight, less tar, more phenolics, and less acidity than when sand is used as bed material. Copyright © 2015 Elsevier Ltd. All rights reserved.

Uranium bed oxidation vacuum process system

International Nuclear Information System (INIS)

McLeland, H.L.

1977-01-01

Deuterium and tritium gases are occluded in uranium powder for release into neutron generator tubes. The uranium powder is contained in stainless steel bottles, termed ''beds.'' If these beds become damaged, the gases must be removed and the uranium oxidized in order not to be flammable before shipment to ERDA disposal grounds. This paper describes the system and methods designed for the controlled degassing and oxidation process. The system utilizes sputter-ion, cryo-sorption and bellows pumps for removing the gases from the heated source bed. Removing the tritium gas is complicated by the shielding effect of helium-3, a byproduct of tritium decay. This effect is minimized by incremental pressure changes, or ''batch'' processing. To prevent runaway exothermic reaction, oxidation of the uranium bed is also done incrementally, or by ''batch'' processing, rather than by continuous flow. The paper discusses in detail the helium-3 shielding effect, leak checks that must be made during processing, bed oxidation, degree of gas depletion, purity of gases sorbed from beds, radioactivity of beds, bed disposal and system renovation

Practice Hospital Bed Safety

Science.gov (United States)

... Home For Consumers Consumer Updates Practice Hospital Bed Safety Share Tweet Linkedin Pin it More sharing options ... It depends on the complexity of the bed." Safety Tips CDRH offers the following safety tips for ...

Estimation of water consumption of tomato crops planted in rock wool bed in greenhouse

International Nuclear Information System (INIS)

Ito, K.; Senge, M.; Iwama, K.; Hashimoto, I.

2002-01-01

For estimating the crop water consumption, it is necessary to determine meteorological data in greenhouse from open field data and calculate potential evaporation. In this study, temperature, humidity, wind velocity and solar radiation were measured in greenhouse as well as in open field. Then, we compared the meteorological data of greenhouse with that of open field. Results of the comparison differed from the reference values of the Official Manual (1997). Humidity during heating period and wind velocity in the greenhouse cannot be evaluated from the steps of the Official Manual. We applied the original equation that was derived in this observation to calculate the potential evaporation in the greenhouse. It became apparent that the potential evaporation could be estimated using open field data. A portion of irrigated water was consumed by vegetation and remainder was discharged from rock wool bed. Mean daily water consumption during the measurement period was 2.50(mm/d), with a monthly maximum occurring in July with 3.54(mm/d). Discharged water amounted to 9% of irrigated water. Tomato's crop coeffieiency with rock wool cultivation was calculated by potential evaporation and water consumption. In this field, this value was smaller than those recorded in the Official Manual. The amount of irrigation was same in all segments of the greenhouse. However, water consumption was affected by incident energy. A portion of discharged water (5% of irrigation water in this greenhouse) could not be saved because there existed a differential volume need for some plants which consumed more water in relation to others

Proceedings of the sixth international conference on fluidized bed combustion. Volume II. Technical sessions

Energy Technology Data Exchange (ETDEWEB)

None

1980-08-01

The Sixth International Conference on Fluidized Bed Combustion was held April 9-11, 1980, at the Atlanta Hilton, Atlanta, Georgia. It was sponsored by the US Department of Energy, the Electric Power Research Institute, the US Environmental Protection Agency, and the Tennessee Valley Authority. The papers covered recent developments in atmospheric and pressurized fluidized-bed combustion, especially the design, operation and control of pilot and demonstration plants. The cleanup of combustion products and the erosion, corrosion and fouling of gas turbines was emphasized also. Fifty-five papers from Volume 2 of the proceedings have been entered individually into EDB and ERA; five papers had been entered previously from other sources. (LTN)

Aquatic Plant Control Research Program: The Habitat Value of Aquatic Macrophytes for Macroinvertebrates

Science.gov (United States)

1989-11-01

seagrass ) and reported that it quickly colonized with algae and invertebrates that were on live plants. Rooke (1986) found considerable dif- ferences...al. (1982) observed that seagrass (Zostera marina) reduced current velocities inside the plant bed, but current velocities were actually higher over...hard-water lakes (Mickle and Wetzel 1978a, 1978b, 1979). Diurnal changes in photosynthesis rates within the boundary layer of macrophyte beds can cause a

Particle fuel bed tests

International Nuclear Information System (INIS)

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

1985-01-01

Gas-cooled reactors, using packed beds of small diameter coated fuel particles have been proposed for compact, high-power systems. The particulate fuel used in the tests was 800 microns in diameter, consisting of a thoria kernel coated with 200 microns of pyrocarbon. Typically, the bed of fuel particles was contained in a ceramic cylinder with porous metallic frits at each end. A dc voltage was applied to the metallic frits and the resulting electric current heated the bed. Heat was removed by passing coolant (helium or hydrogen) through the bed. Candidate frit materials, rhenium, nickel, zirconium carbide, and zirconium oxide were unaffected, while tungsten and tungsten-rhenium lost weight and strength. Zirconium-carbide particles were tested at 2000 K in H 2 for 12 hours with no visible reaction or weight loss

Plant Immunity against Viruses: Moving from the Lab to the Field

Directory of Open Access Journals (Sweden)

Nam-Yeon Kim

2018-03-01

Full Text Available Plant viruses cause significant yield losses and continuously threaten crop production, representing a serious threat to global food security. Studies on plant-virus interactions have contributed to increase our knowledge on plant immunity mechanism, providing new strategies for crop improvement. The prophylactic managements consist mainly following international legislations, eradication of infected plants, and application of pesticide to decrease the population of vectors. Hence, putting together the pieces of knowledge related to molecular plant immunity to viruses is critical for the control of virus disease in fields. Over the last several decades, the outstanding outcomes of extensive research have been achieved on comprehension of plant immunity to viruses. Although most dominant R genes have been used as natural resistance genes, recessive resistance genes have been deployed in several crops as another efficient strategy to control viruses. In addition, RNA interference also regulates plant immunity and contribute a very efficient antiviral system at the nucleic acid level. This review aims at describing virus disease on crops and summarizes current resistance mechanisms. Furthermore, we will discuss the current biotechnological approaches to control viral diseases and the future questions that are to be addressed to secure crop production against viruses.

Plant abnormality inspection device

International Nuclear Information System (INIS)

Takenaka, Toshio.

1990-01-01

The present invention concerns a plant abnormality inspection device for conducting remote or automatic patrolling inspection in a plant and, more particularly, relates to such a device as capable of detecting abnormal odors. That is, the device comprises a moving device for moving to a predetermined position in the plant, a plurality of gas sensors for different kind of gases to be inspected mounted thereon, a comparator for comparing the concentration of a gas detected by the gas sensor with the normal gas concentration at the predetermined position and a judging means for judging the absence or presence of abnormality depending on the combination of the result of the comparison and deliverying a signal if the state is abnormal. As a result, a slight amount of gas responsible to odors released upon abnormality of the plant can be detected by a plurality of gas sensors for different kinds gases to rapidly and easily find abnormal portions in the plant. (I.S.)

Chaotic hydrodynamics of fluidized beds

Energy Technology Data Exchange (ETDEWEB)

Van der Stappen, M.L.M. [Unit Process and Systems Engineering, Advanced Manufacturing Technology Group, Unilever Research Laboratorium, Vlaardingen (Netherlands)

1996-12-31

The major goals of this thesis are: (1) to develop and evaluate an analysis method based on techniques from non-linear chaos theory to characterize the nonlinear hydrodynamics of gas-solids fluidized beds quantitatively; and (2) to determine the dependence of the chaotic invariants on the operating conditions and investigate how the chaos analysis method can be profitably applied to improve scale-up and design of gas-solids fluidized bed reactors. Chaos theory is introduced in chapter 2 with emphasis on analysis techniques for (experimental) time series, known from literature at the start of this work (1990-1991). In chapter 3, the testing of existing and newly developed techniques on both model and fluidized bed data is described. This leads to the development of the chaos analysis method to analyze measured pressure fluctuations time series of a fluidized bed. Following, in chapter 4, this method is tested and all choices for the parameters are evaluated. The influence of the experimental parameters and external disturbances on the measurements and analysis results is discussed and quantified. The result is a chaos measurement and analysis protocol, which is further used in this work. In chapter 5, the applications to fluidized beds are discussed. It is shown that the entropy is a good measure for the characterization of the dynamical behavior of gas-solids bubbling/slugging fluidized beds. Entropy is applied to characterize the influence of the operating conditions, to assess regime transitions and to analyze dimensionless similar beds of different scale. Quantitative design correlations that relate entropy to the operating parameters (including the bed diameter) are described. Finally, it is discussed how the results of this work might be used in scaling up the chaotic dynamics of fluidized beds. The overall conclusions and outlook from this work are presented in chapter 6. 182 refs.

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

Effects of bed-load movement on flow resistance over bed forms

Indian Academy of Sciences (India)

Abstract. The effect of bed-load transport on flow resistance of alluvial channels with undulated bed was experimentally investigated. The experiments were carried out in a tilting flume 250mm wide and 12·5m long with glass-sides of rectan- gular cross-section and artificial dune shaped floor that was made from Plexi-glass.

Experimental studies on combustion of composite biomass pellets in fluidized bed.

Science.gov (United States)

Guo, Feihong; Zhong, Zhaoping

2017-12-01

This work presents studies on the combustion of Composite Biomass Pellets (CBP S ) in fluidized bed using bauxite particles as the bed material. Prior to the combustion experiment, cold-flow characterization and thermogravimetric analysis are performed to investigate the effect of air velocity and combustion mechanism of CBP S . The cold-state test shows that CBPs and bauxite particles fluidize well in the fluidized bed. However, because of the presence of large CBPs, optimization of the fluidization velocity is rather challenging. CBPs can gather at the bottom of the fluidized bed at lower gas velocities. On the contrary, when the velocity is too high, they accumulate in the upper section of the fluidized bed. The suitable fluidization velocity for the system in this study was found to be between 1.5-2.0m/s. At the same time, it is found that the critical fluidization velocity and the pressure fluctuation of the two-component system increase with the increase of CBPs mass concentration. The thermogravimetric experiment verifies that the combustion of CBPs is a first-order reaction, and it is divided into three stages: (i) dehydration, (ii) release and combustion of the volatile and (iii) the coke combustion. The combustion of CBPs is mainly based on the stage of volatile combustion, and its activation energy is greater than that of char combustion. During the combustion test, CBP S are burned at a 10kg/h feed rate, while the excess air is varied from 25% to 100%. Temperatures of the bed and flue gas concentrations (O 2 , CO, SO 2 and NO) are recorded. CBPs can be burnt stably, and the temperature of dense phase is maintained at 765-780°C. With the increase of the air velocity, the main combustion region has a tendency to move up. While the combustion is stable, O 2 and CO 2 concentrations are maintained at about 7%, and 12%, respectively. The concentration of SO 2 in the flue gas after the initial stage of combustion is nearly zero. Furthermore, NO concentration

Measuring discharge with acoustic Doppler current profilers from a moving boat

Science.gov (United States)

Mueller, David S.; Wagner, Chad R.; Rehmel, Michael S.; Oberg, Kevin A.; Rainville, Francois

2013-01-01

The use of acoustic Doppler current profilers (ADCPs) from a moving boat is now a commonly used method for measuring streamflow. The technology and methods for making ADCP-based discharge measurements are different from the technology and methods used to make traditional discharge measurements with mechanical meters. Although the ADCP is a valuable tool for measuring streamflow, it is only accurate when used with appropriate techniques. This report presents guidance on the use of ADCPs for measuring streamflow; this guidance is based on the experience of U.S. Geological Survey employees and published reports, papers, and memorandums of the U.S. Geological Survey. The guidance is presented in a logical progression, from predeployment planning, to field data collection, and finally to post processing of the collected data. Acoustic Doppler technology and the instruments currently (2013) available also are discussed to highlight the advantages and limitations of the technology. More in-depth, technical explanations of how an ADCP measures streamflow and what to do when measuring in moving-bed conditions are presented in the appendixes. ADCP users need to know the proper procedures for measuring discharge from a moving boat and why those procedures are required, so that when the user encounters unusual field conditions, the procedures can be adapted without sacrificing the accuracy of the streamflow-measurement data.

Product removal and solids transport from fluidized-bed calciners

International Nuclear Information System (INIS)

Grimmett, E.S.; Munger, D.H.

1978-09-01

Methods of removing the solid product from pilot-plant and production fluidized-bed calciners, and transporting product to underground storage vaults are reported here. Testing of dense-phase solids transport systems in test loops during development of a 15-cm-diam. and 30-cm-diam. calciner are described. A lean-phase solid transport system is used with the Waste Calcining Facility. The results of some recent tests done in a lean-phase transport system connected to the 30-cm-diam. calciner are included in this report

Fuel Gas Demonstration Plant Program. Volume I. Demonstration plant