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1

EPR study of deoxygenated high-temperature superconductors  

International Nuclear Information System (INIS)

High-Tc superconductors are EPR silent but on a little deoxygenation of the high-Tc materials and their constituents, they yield rich but complex spectra. Spectra of (1) CuO, (2) BaCuO2, (3) CaCuO2, (4) Y2Cu2O5, (5) La2CuO4, (6) La2-xMxCuO4 (M = Sr, Ba), (7)Y based-123, (8)Bi based-2201, 2212, 2223, (9) Tl based-2223 and (10) Hg based-1212,1223 have been studied. One thing common to all these materials is the CuO2 plane which gets fragmented on deoxygenation and the inherent antiferromagnetic coupling is partially destroyed which results in the appearance of the spectra. Very big fragments do not give any spectra because the original AF order probably remains intact in them. It is expected that when the fragments become magnetically isolated from the bulk, they produce EPR spectra. Most of the spectra have been analyzed and their spin-Hamiltonian parameters determined. The spectra of these species vary a little in terms of g-value and fine-structure splitting constant from sample to sample or even in the same sample and this may be attributed to some extra oxygen attachments retained with these species. Most frequently occurring species is the Cu-tetramer, (CuO)4. As (CuO)4 represents the unit cell of the all important two-dimensional CuO2 plane of the high- Tc materials, its spectra have been argued to provide some clue to the mechanism of high-Tc superconductivity. The tetramer (CuO)4 is a four one-half spin system and is essentially 16-fold degenerate by Heisenberg isotropic exchange, it is split into 6 components: one pentet, three triplets and two singlets. In superconductors the pentet appears to be the ground state and in the non-superconducting constituents the singlets seem to form the ground state as revealed by the temperature variation studies. In the case of La1.854Sr0.146CuO4 we have found the signature of quantum stripe formation. The high-Tc superconductivity theories involving spin bag, anti ferromagnetic spin fluctuations and magnons can be explained on the basis of Cu-tetramers

2001-09-25

2

Determination of Pyrolysis Temperature for Charring Materials.  

Science.gov (United States)

An energy and mass balanced method of determining the pyrolysis temperature is proposed. The concept is to find the pyrolysis temperature that consumes the same amount of energy to produce the same amount of mass when using the pyrolysis front model as wh...

A. Atreya H. R. Baum W. C. Park

2007-01-01

3

Low-temperature, selective catalytic deoxygenation of vegetable oil in supercritical fluid media.  

Science.gov (United States)

The effects of supercritical fluids on the production of renewable diesel-range hydrocarbons from natural triglycerides were investigated. Various supercritical fluids, which included CO2 (scCO2 ), propane (scC3 H8 ) and n-hexane (scC6 H14 ), were introduced with H2 and soybean oil into a fixed-bed reactor that contained pre-activated CoMo/?-Al2 O3 . Among these supercritical fluids, scC3 H8 and scC6 H14 efficiently allowed the reduction of the reaction temperature by as much as 50 C as a result of facilitated heat and mass transfer and afforded similar yields to reactions in the absence of supercritical fluids. The compositional analyses of the gas and liquid products indicated that the addition of scC3 H8 during the hydrotreatment of soybean oil promoted specific deoxygenation pathways, decarbonylation and decarboxylation, which consumed less H2 than the hydrodeoxygenation pathway. As a result, the quantity of H2 required to obtain a high yield of diesel-range hydrocarbons could be reduced to 57 % if scC3 H8 was used. As decarboxylation and decarbonylation are mildly endothermic reactions, the reduced heat transfer resistance in scC3 H8 may drive the deoxygenation reaction to thermodynamically favourable pathways. PMID:24339322

Kim, Seok Ki; Lee, Hong-Shik; Hong, Moon Hyun; Lim, Jong Sung; Kim, Jaehoon

2014-02-01

4

Pyrolysis of biomass. Rapid pyrolysis at high temperature. Slow pyrolysis for active carbon preparation.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Pyrolysis of biomass consists of heating solid biomass inthe absence of air to produce solid, liquid and gaseous fuels.In the first part of this thesis rapid pyrolysis of wood(birch) and some agricultural residues (olive waste, sugarcanebagasse and wheat straw in untreated and in pelletized form) athigh temperature (800C?1000C) is studied ina free fall reactor at pilot scale. These conditions are ofinterest for gasification in fluidized beds. Of main interestare the gas and char yiel...

Zanzi, Rolando

2001-01-01

5

Experimental study on low temperature pyrolysis of forestry residues  

Energy Technology Data Exchange (ETDEWEB)

Biomass low temperature pyrolysis is a thermo-chemical treatment method that is earmarked by an pyrolysis temperature ranging from 200 to 300 C (under anoxic, heating rates {<=} 50 C/min). This paper investigates the low temperature pyrolysis properties of the raw biomass, including mulberry branch and wood chips, which collected from Jiangsu, China was carried out in a self-designed continuous pyrolysis facility. The experiments were carried out at pyrolysis temperatures of 250 {proportional_to} 300 C and residence time of 10 {proportional_to} 30 min. The results show that the mass yield of mulberry branch charcoal decreased with the increasing of the pyrolysis temperature and residence time, and the pyrolysis temperature has a significant effect on low temperature pyrolysis than the residence time. The fixed carbon and elemental carbon content of the biomass charcoals increased and volatile matters, hydrogen and oxygen contents of biomass charcoals decreased with the increasing of the pyrolysis temperature and residence time, which results in the decreasing of H/C and O/C ratios. The energy density continues to increase with increase in the pyrolysis temperature and residence time. After the pre-treatment, the biomass charcoal compared with raw biomass gained a high energy density and the improvement of hydrophobicity (OH groups are responsible for hydrogen bonding with water). SEM micrographs of mulberry branch and mulberry branch charcoals show that the porosity and the degree of thermal degradation increase with increasing of the pyrolysis temperature. After based on a systematic consideration, the operating condition of 275 C and 10 min was recommended.

Wang, Qinchao; Shu, Tong; Lu, Fei; Lu, Ping [Nanjing Normal Univ. (China). School of Energy and Mechanical Engineering

2013-07-01

6

Pyrolysis and gasification of coal at high temperatures  

Energy Technology Data Exchange (ETDEWEB)

We made considerable progress towards completing the development of a thermogravimetric reactor with video microscopy imaging capabilities (TGA/VMI). The video micrOSCOPY components were designed, installed and are currently under testing. With the newly developed TGA/VNH apparatus we can directly observe macroscopic changes in the morphology of pyrolyzing particles and thermal ignitions of burning particles while simultaneously monitoring the weight of pyrolyzing or reacting samples. The systematic investigation on the effects of pyrolysis conditions and char macropore structure on char reactivity continued. Pyrolysis and gasification experiments were performed consecutively in our TGA reactor and the char reactivity patterns were measured for a wide range of temperatures (400--600[degrees]C). These conditions cover both the kinetic and the diffusion limited regimes. Our results show conclusively that chars produced at high pyrolysis heating rates (and, therefore, having a more open cellular macropore structure) are more reactive and ignite more easily than chars pyrolyzed at low heating rates. These results have been explained using theoretical models. We also investigated for the first time the effect of coal particle size and external mass transfer limitations on the reactivity patterns and ignition behavior of char particles combusted in air. Finally, we used our hot stage reactor to monitor the structural transformations occurring during pyrolysis via a video microscopy system. Pyrolysis experiments were videotaped and particle swelling and the particle ignitions were determined and analyzed using digitized images from these experiments.

Zygourakis, K.

1990-01-01

7

High-temperature pyrolysis mechanisms of coal model compounds  

Energy Technology Data Exchange (ETDEWEB)

The degradation of the carboxylic acid group has been examined with respect to potential pretreatment strategies for fossil fuel conversion processes. In one potential pretreatment strategy involving cation exchange of the carboxylic acid group, a series of benzoic acid and stearic acid salts have been chosen to model the tight'' carboxylic acids of immature fossil fuel feedstocks and have been pyrolyzed with an entrained flow reactor. Our preliminary results indicate that Group I and II salts yield primarily the parent acid. Benzoate salts also yield small amounts of benzene while the stearic acid salts give no other detectable products. In two alternative treatment strategies, esterification and anhydride preparation have also been accomplished with these compounds being subjected to the entrained flow reactor conditions. The benzoate esters give a number of products, such as benzaldehyde, benzene, and low MW gases. The formation of these compounds is extremely dependent on pyrolysis conditions and alkoxy chain length. A xenon flashlamp and an entrained flow reactor have been used to heat organic substrates to varying temperatures using different heating rates. Ultrarapid flashlamp pyrolysis (heating rate>10{sup 50}C/s) has been performed. Since the ultrarapid pyrolysis products differ from those observed with traditional heating techniques and differ from the products formed photochemically, the flashlamp pyrolysis products are attributed to high temperature thermal activation.

Penn, J.H.; Owens, W.H.

1991-01-01

8

Pyrolysis and gasification of coal at high temperatures  

Energy Technology Data Exchange (ETDEWEB)

Coals of different ranks will be pyrolyzed in a microscope hot-stage reactor using inert and reacting atmospheres. The macropore structure oft he produced chars will be characterized using video microscopy and digital image processing techniques to obtain pore size distributions. Comparative studies will quantify the effect of pyrolysis conditions (heating rates, final heat treatment temperatures, particle size and inert or reacting atmosphere) on the pore structure of the devolatilized chars. The devolatilized chars will be gasified in the regime of strong intraparticle diffusional limitations using O{sub 2}/N{sub 2} and O{sub 2}/H{sub 2}/N{sub 2} mixtures. Constant temperature and programmed-temperature experiments in a TGA will be used for these studies. Additional gasification experiments performed in the hot-stage reactor will be videotaped and selected images will be analyzed to obtain quantitative data on particle shrinkage and fragmentation.

Zygourakis, K.

1989-01-01

9

Effect of pyrolysis temperature and heating rate on biochar obtained from pyrolysis of safflower seed press cake.  

Science.gov (United States)

Biochar is carbon-rich product generated from biomass through pyrolysis. In this study, the effects of pyrolysis temperature and heating rate on the yield and physicochemical and morphological properties of biochars obtained from safflower seed press cake were investigated. The results showed that the biochar yield and quality depend principally on the applied temperature where pyrolysis at 600 C leaves a biochar with higher fixed carbon content (80.70%) and percentage carbon (73.75%), and higher heating value (30.27 MJ kg(-1)) in comparison with the original feedstock (SPC) and low volatile matter content (9.80%). The biochars had low surface areas (1.89-4.23 m(2)/g) and contained predominantly aromatic compounds. The biochar could be used for the production of activated carbon, in fuel applications, and water purification processes. PMID:23211485

Ang?n, Dilek

2013-01-01

10

Effect of pyrolysis temperature on porous structure of anthracite chars produced at high temperatures  

Energy Technology Data Exchange (ETDEWEB)

An experimental study was conducted on the porous structure of the char particles of IX anthracite by using nitrogen absorption method. The coal chars were produced under high temperatures ranging from 1500 K to 1800 K in a drop tube furnace. The distributions of specific surface area and pore volume with pore diameter were derived by using BET and BIH methods. It is found that the pores in micro-size and meso-size are major contributors for the overall specific surface area and pore volume. Furthermore, with the increasing of pyrolysis temperature, the specific area and pore volume vary in the shape of mountain and the temperature of peake is around 1600 K. The SEM observation shows that the surface of char particles becomes smoother and denser when the pyrolysis temperature is higher than 1 600 K. It is suggested that the melting of internal ash during high temperature pyrolysis is the main cause for such a phenomenon, and thus the turning point is related to the melting point of the char. l5 refs., 7 figs., 1 tab.

Zhou, Jun; Zhang, Hai; Lu, Jun-fu; Yue, Guang-xi [Tsinghua University, Beijing (China). Department of Thermal Engineering

2007-07-01

11

Yield and Characteristics of Pyrolysis Products Obtained from Schizochytrium limacinum under Different Temperature Regimes  

Directory of Open Access Journals (Sweden)

Full Text Available Pyrolysis-gas chromatographic mass spectrometry (Py-GC/MS was used to determine the yield and chemical composition of the pyrolysis products of Schizochytrium limacinum. The pyrolysis was carried out by varying the temperature from 300 C to 800 C. It was found that the main decomposition temperature of Schizochytrium limacinum was 428.16 C, at which up to 66.5% of the mass was lost. A further 18.7% mass loss then occurred in a relatively slow pace until 760.2 C due to complete decomposition of the ash content of Schizochytrium limacinum. The pyrolysis of Schizochytrium limacinum at 700 C produced the maximum yield (67.7% of pyrolysis products compared to 61.2% at 400 C. While pollutants released at 700 C (12.3% was much higher than that of 400 C (2.1%. Higher temperature will lead to more pollutant (nitrogen compounds and PAHs release, which is harmful to the environment. Considering the reasonably high yield and minimum release of pollutants, a lower pyrolysis temperature (400 C was found to be optimum for producing biofuel from Schizochytrium limacinum.

Renjie Dong

2013-07-01

12

Cellulose-hemicellulose and cellulose-lignin interactions in wood pyrolysis at gasification temperature  

Energy Technology Data Exchange (ETDEWEB)

Cellulose-hemicellulose and cellulose-lignin interactions during pyrolysis at gasification temperature (800 C) were investigated with various cellulose samples mixed with hemicellulose (glucomannan or xylan) or milled wood lignin. Significant interactions were observed in cellulose-lignin pyrolysis; lignin inhibited the thermal polymerization of levoglucosan formed from cellulose and enhanced the formation of the low molecular weight products from cellulose with reduced yield of char fraction; cellulose reduced the secondary char formation from lignin and enhanced the formation of some lignin-derived products including guaiacol, 4-methyl-guaiacol and 4-vinyl-guaiacol. Comparatively weak interactions were also observed in cellulose-hemicellulose pyrolysis. Finally, factors influencing the wood pyrolysis at gasification temperature are discussed. (author)

Hosoya, T.; Kawamoto, H.; Saka, S. [Graduate School of Energy Science, Kyoto University, Yoshida-Honmachi, Sakyo-ku, Kyoto 606-8501 (Japan)

2007-08-15

13

Catalytic pyrolysis of biomass: Effects of pyrolysis temperature, sweeping gas flow rate and MgO catalyst  

International Nuclear Information System (INIS)

Cotton seed, as a biomass source, is pyrolysed in a tubular fixed-bed reactor under various sweeping gas (N2) flow rates at different pyrolysis temperatures. In the non-catalytic work, the maximum bio-oil yield was attained as 48.30% at 550 oC with a sweeping gas flow rate of 200 mL min-1. At the optimum conditions, catalytic pyrolysis of biomass samples was performed with various amounts of MgO catalyst (5, 10, 15, and 20 wt.% of raw material). Catalyst addition decreased the quantity of bio-oil yet increased the quality of bio-oil in terms of calorific value, hydrocarbon distribution and removal of oxygenated groups. It was observed that increasing the amount of catalyst used, decreased the oil yields while increased the gas and char yields. Bio-oils obtained at the optimum conditions were separated into aliphatic, aromatic and polar sub-fractions. After the application of column chromatography, bio-oils were subjected into elemental, FT-IR and 1H NMR analyses. Aliphatic sub-fractions of bio-oils were analyzed by GC-MS. It was deduced that the fuel obtained via catalytic pyrolysis mainly consisted of lower weight hydrocarbons in the diesel range. Finally, obtained results were compared with petroleum fractions and evaluated as a potential source for liquid fuels.

2010-07-01

14

Biophysical basis of hypoxic radioprotection by deoxygenated dextran-hemoglobin  

International Nuclear Information System (INIS)

Perfusion with deoxygenated dextran-hemoglobin provides an effective method for inducing hypoxic radioprotection of normal tissues during radiation treatment of tumors. In this study, the dependence of P50, the half-saturation pressure of oxygen binding to dextran-hemoglobin, was analyzed as a function of solution temperature and pH. The variation of attainable radioprotection with P50, and with the amount of collateral blood entering into the perfused region, was calculated. Upon perfusion of canine gracilis muscle with deoxygenated dextran-hemoglobin, a rapid onset of extensive venous hypoxia was observed

1986-01-01

15

Pyrolysis Oil from the Fruit and Cake of Jatropha curcas Produced Using a Low Temperature Conversion (LTC) Process: Analysis of a Pyrolysis Oil-Diesel Blend  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Background: The LTC process is a technique that consists of heating solid residues at a temperature of 380oC - 420oC in an inert atmosphere and their products are evaluated individually: these products include pyrolysis oil, pyrolytic char, gas and water. The objective of this study was to compare the effects of the use of oils obtained by pyrolysis of Jatropha curcas as an additive for diesel in different proportions. Results: A Low Temperature C...

Monique Kort-Kamp Figueiredo; Gilberto Alves Romeiro; Raquel Vieira Santana Silva; Priscila Alvares Pinto; Raimundo Nonato Damasceno; Avila, Luiz Antonio D.; Franco, Amanda P.

2011-01-01

16

A review of the toxicity of biomass pyrolysis liquids formed at low temperatures  

Energy Technology Data Exchange (ETDEWEB)

The scaleup of biomass fast pyrolysis systems to large pilot and commercial scales will expose an increasingly large number of personnel to potential health hazards, especially during the evaluation of the commercial use of the pyrolysis condensates. Although the concept of fast pyrolysis to optimize liquid products is relatively new, low-temperature pyrolysis processes have been used over the aeons to produce charcoal and liquid by-products, e.g., smoky food flavors, food preservatives, and aerosols containing narcotics, e.g., nicotine. There are a number of studies in the historical literature that concern the hazards of acute and long-term exposure to smoke and to the historical pyrolysis liquids formed at low temperatures. The reported toxicity of smoke, smoke food flavors, and fast pyrolysis oils is reviewed. The data found for these complex mixtures suggest that the toxicity may be less than that of the individual components. It is speculated that there may be chemical reactions that take place that serve to reduce the toxicity during aging. 81 refs.

Diebold, J P [Thermalchemie, Inc., Lakewood, CO (United States)

1997-04-01

17

Influence of Pyrolysis Temperature on Rice Husk Char Characteristics and Its Tar Adsorption Capability  

Directory of Open Access Journals (Sweden)

Full Text Available A biomass waste, rice husk, was inspected by thermoanalytical investigation to evaluate its capability as an adsorbent medium for tar removal. The pyrolysis process has been applied to the rice husk material at different temperatures 600, 800 and 1000 C with 20 C/min heating rate, to investigate two topics: (1 influence of temperature on characterization of rice husk char and; (2 adsorption capability of rice husk char for tar removal. The results showed that subsequent to high temperature pyrolysis, rice husk char became a highly porous material, which was suitable as tar removal adsorbent with the ability to remove tar effectively. In addition, char characteristics and tar removal ability were significantly influenced by the pyrolysis temperature.

Anchan Paethanom

2012-11-01

18

Hydrogen from biomass via pyrolysis: relationships between yield of hydrogen and temperature  

Energy Technology Data Exchange (ETDEWEB)

Hydrogen is a sustainable, non-polluting source of energy that can be used in mobile and stationary applications. The use of hydrogen as an energy carrier or major fuel requires development in several industry segments including production, delivery, storage, conversion, and end-use. It is an obvious alternative to hydrocarbon fuels such as gasoline. Hydrogen can be produced through thermal, electrolytic, or photolytic processes applied to fossil fuels, biomass, or water. The yields of gaseous products from pyrolysis runs of the biomass samples increase with increasing pyrolysis temperature. The yield of hydrogen in gaseous products from the samples of hazelnut shell, cotton cocoon shell, tea factory waste, olive husk, beech wood and spruce wood increased from 34.0 to 54.8%, 22.1 to 41.0%, 28.9 to 47.8%, 36.0 to 50.6%, 31.5 to 48.3%, and 33.2 to 49.6%, respectively, while the final pyrolysis temperature increased from 650 to 1025 K. There is a relationship between the yield of hydrogen in a gaseous product from the biomass sample and pyrolysis temperature. The yield of hydrogen is a linear function of the pyrolysis temperature. (Author)

Demirbas, Ayhan [Selcuk Univ., Dept. of Chemical Engineering, Campus-Konya (Turkey); Arin, Gonenc [Gazi Univ., Dept. of Chemical Engineering, Ankara (Turkey)

2004-09-15

19

PYROLYSIS OF EMPTY FRUIT BUNCHES: INFLUENCE OF TEMPERATURE ON THE YIELDS AND COMPOSITION OF GASEOUS PRODUCT  

Directory of Open Access Journals (Sweden)

Full Text Available With the increasing concern on fossil fuel depletion and environmental problems, the utilization of renewable biomass resources is expected to play an important role in the future. Biomass can be converted into a variety of fuels and chemicals by different processes; one of which is pyrolysis that has been subjected to extensive research in recent years. In this study, pyrolysis of oil palm Empty Fruit Bunches (EFB was investigated using a quartz fluidised-fixed bed reactor. The effects of pyrolysis temperatures on the yields and composition of gaseous products were investigated. The temperatures of pyrolysis used were in the range of 300-600C. The gaseous products from pyrolysis of (EFB were analyzed using a dual-channel micro-GC with Thermal Conductivity Detector (TCD. The highest and lowest gas yields obtained were 42.98 and 31.55% at 600 and 300C, respectively. The gases detected were Carbon Monoxide (CO, carbon dioxide (CO2, Methane (CH4, Ethane (C2H6 and Ethylene (C2H4. At 300 and 400C, the gas mixture comprised mainly CO2 (20% and CO (20%. Other gases such as CH4, C2H4 and C2H6 only evolved at higher temperature starting from 400C with the yield of the latter two gases in very low concentration.

Mohamad Azri Sukiran

2014-01-01

20

Effect of pyrolysis temperature on chemical and surface properties of biochar of rapeseed (Brassica napus L.).  

Science.gov (United States)

The biochar is an important carbon-rich product that is generated from biomass sources through pyrolysis. Biochar (charcoal) can be both used directly as a potential source of solid biofuels and as soil amendments for barren lands. The aim of this study was investigate influence of pyrolysis temperature on the physicochemical properties and structure of biochar. The biochars were produced by pyrolysis of rapeseed (Brassica napus L.) using a fixed-bed reactor at different pyrolysis temperatures (400-700 degrees C). The produced biochars were characterized by proximate and elemental analysis, Brunauer-Emmett-Teller (BET) surface area, particle size distributions, scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy. The results showed that both chemical and surface properties of the biochars were significantly affected by the pyrolysis temperature. Aromatic hydrocarbons, hydroxyl and carbonyl compounds were the majority components of the biochar. The biochar obtained at 700 degrees C had a high fixed carbon content (66.16%) as well as a high heating value, and therefore it could be used as solid fuel, precursor in the activated carbons manufacture (specific surface area until 25.38 m(2) g(-1)), or to obtain category-A briquettes. PMID:24933878

Angin, Dilek; Sensz, Sevgi

2014-01-01

 
 
 
 
21

Mathematical modelling of the temperature response of low-rank coal particles during pyrolysis  

Energy Technology Data Exchange (ETDEWEB)

A mathematical model has been developed to predict the temperature response of dry low-rank coal particles during pyrolysis in an inert atmosphere. The model is based on the unsteady-state heat conduction equation in spherical coordinates and uses the Distributed Activation Energy Model to predict volatiles evolution. Measurements of the temperature response at the centre of lO mm Bowmans coal particles were conducted in a horizontal tube furnace using nitrogen as the heating medium at furnace temperatures of 150{degree}C, 350{degree}C, 600{degree}C, 700{degree}C, and 800{degree}C. A sensitivity analysis was performed to assess the influence of the heat of pyrolysis and the flux of volatiles leaving the particle on the temperature response. The heat of pyrolysis can influence the predicted temperature response, however the uncertainty surrounding the magnitude and nature of its value remains a problem. The gaseous flux has no significant effect on the model predictions. Measurements of the temperature response of particles with varying moisture contents indicate that the presence of moisture significantly influences the temperature response. The effect of moisture is greater than that of the heat of pyrolysis and further work is required to incorporate moisture into the current model. 24 refs., 6 figs., 3 tabs.

Heidenreich, C.A.; Yan, H.M.; Zhang, D.K. [University of Adelaide, Adelaide, SA (Australia). CRC for New Technologies for Power Generation from Low-rank Coal, Dept. of Chemical Engineering

1998-11-01

22

Pyrolysis Oil from the Fruit and Cake of Jatropha curcas Produced Using a Low Temperature Conversion (LTC Process: Analysis of a Pyrolysis Oil-Diesel Blend  

Directory of Open Access Journals (Sweden)

Full Text Available Background: The LTC process is a technique that consists of heating solid residues at a temperature of 380oC - 420oC in an inert atmosphere and their products are evaluated individually: these products include pyrolysis oil, pyrolytic char, gas and water. The objective of this study was to compare the effects of the use of oils obtained by pyrolysis of Jatropha curcas as an additive for diesel in different proportions. Results: A Low Temperature Conversion (LTC process carried out on samples of Jatropha curcas fruit and generated pyrolysis oil, pyrolyic char, gas and aqueous fractions in relative amounts of 23, 37, 16 and 14% [w/w] respectively for Jatropha curcas fruit and 19, 47, 12 and 22% [w/w] respectively for Jatropha curcas cake. The oil fractions were analyzed by FTIR, 1H NMR, 13C NMR, GCMS and physicochemical analysis. The pyrolysis oil was added to final concentrations of 2, 5, 10 and 20% [w/w] to commercial diesel fuel. The density, viscosity, sulfur content and flash point of the mixtures were determined. Conclusions: The results indicated that the addition of the pyrolysis oil maintained the mixtures within the standards of the diesel directive, National Petroleum Agency (ANP no 15, of 19. 7. 2006, with the exception of the viscosity of the mixtures containing 20% pyrolysis oil.

Monique Kort-Kamp Figueiredo

2011-07-01

23

Effects of pyrolysis temperature on the physicochemical properties of empty fruit bunch and rice husk biochars.  

Science.gov (United States)

Biochar has received great attention recently due to its potential to improve soil fertility and immobilize contaminants as well as serving as a way of carbon sequestration and therefore a possible carbon sink. In this work, a series of biochars were produced from empty fruit bunch (EFB) and rice husk (RH) by slow pyrolysis at different temperatures (350, 500, and 650C) and their physicochemical properties were analysed. The results indicate that porosity, ash content, electrical conductivity (EC), and pH value of both EFB and RH biochars were increased with temperature; however, yield, cation exchange capacity (CEC), and H, C, and N content were decreased with increasing pyrolysis temperature. The Fourier transform IR spectra were similar for both RH and EFB biochars but the functional groups were more distinct in the EFB biochar spectra. There were reductions in the amount of functional groups as pyrolysis temperature increased especially for the EFB biochar. However, total acidity of the functional groups increased with pyrolysis temperature for both biochars. PMID:24643171

Claoston, N; Samsuri, A W; Ahmad Husni, M H; Mohd Amran, M S

2014-04-01

24

Trichloroethylene adsorption by pine needle biochars produced at various pyrolysis temperatures.  

Science.gov (United States)

In this study, pine needles were converted to biochar (BC) at different pyrolysis temperatures of 300, 500, and 700 C to sorb trichloroethylene (TCE), and the changes in BC properties with each temperature were evaluated. Pyrolysis temperature showed a pronounced effect on BC properties. Decreases in molar H/C and O/C ratios resulted from removing O- and H-containing functional groups with increasing temperature, and produced high aromaticity and low polarity BCs. BCs produced at higher temperature showed greater TCE removal efficiency from water due to their high surface area, micro-porosity, and carbonized extent. The performance of various BCs for TCE removal was assessed by the Freundlich, Langmuir, Temkin, and Dubinin-Radushkevich adsorption models, among which the Temkin and Dubinin-Radushkevich models best described TCE adsorption onto various BCs, indicating prevailing sorption mechanism as pore-filling. PMID:23838320

Ahmad, Mahtab; Lee, Sang Soo; Rajapaksha, Anushka Upamali; Vithanage, Meththika; Zhang, Ming; Cho, Ju Sik; Lee, Sung-Eun; Ok, Yong Sik

2013-09-01

25

Preparation of Organic/Inorganic Membrane by PDMS Low-temperature Pyrolysis  

Directory of Open Access Journals (Sweden)

Full Text Available The organic/inorganic membranes were prepared via low-temperature pyrolysis of polymers. Firstly, polymeric membranes were prepared by dip-coating method using PDMS as the precursor and stainless steel as the support. Then they were pyrolyzed at 350-480C under inert atmosphere. The effects of preparation conditions on the gas separation performance of the organic/inorganic membranes were investigated. Chemical structure changes of PDMS in the pyrolysis process were studied by TG and FT-IR. The morphology of organic/inorganic membrane was characterized by SEM. The results showed that the organic/inorganic membranes with good gas separation performance could be successfully prepared by low-temperature pyrolysis of PDMS. The membrane retains part flexibility of PDMS, and presents good thermostability and high gas permselectivity. The gas separation performance and membrane layer structure of organic/inorganic membranes are greatly affected by the preparation conditions such as the PDMS concentration, coating times, pyrolysis temperature and properties of support. The gas separation performances prepared under the optimum condition are that the O2 permeation flux of 21.2 GPU(1 GPU=7.50110-12m3(STP/(m2?s?Pa and O2/N2 selectivity of 2.28.

YU Jiao-Zhu, LI Lin, JIN Xin, DING Ling-Hua, WANG Tong-Hua

2014-02-01

26

Recycling of automobile shredder residue with a microwave pyrolysis combined with high temperature steam gasification  

International Nuclear Information System (INIS)

Presently, there is a growing need for handling automobile shredder residues - ASR or 'car fluff'. One of the most promising methods of treatment ASR is pyrolysis. Apart of obvious benefits of pyrolysis: energy and metals recovery, there is serious concern about the residues generated from that process needing to be recycled. Unfortunately, not much work has been reported providing a solution for treatment the wastes after pyrolysis. This work proposes a new system based on a two-staged process. The ASR was primarily treated by microwave pyrolysis and later the liquid and solid products become the feedstock for the high temperature gasification process. The system development is supported within experimental results conducted in a lab-scale, batch-type reactor at the Royal Institute of Technology (KTH). The heating rate, mass loss, gas composition, LHV and gas yield of producer gas vs. residence time are reported for the steam temperature of 1173 K. The sample input was 10 g and the steam flow rate was 0.65 kg/h. The conversion reached 99% for liquids and 45-55% for solids, dependently from the fraction. The H2:CO mol/mol ratio varied from 1.72 solids and 1.4 for liquid, respectively. The average LHV of generated gas was 15.8 MJ/N m3 for liquids and 15 MJ/N m3 for solids fuels.

2010-10-15

27

High-temperature pyrolysis mechanisms of coal model compounds. 1990 annual report  

Energy Technology Data Exchange (ETDEWEB)

The degradation of the carboxylic acid group has been examined with respect to potential pretreatment strategies for fossil fuel conversion processes. In one potential pretreatment strategy involving cation exchange of the carboxylic acid group, a series of benzoic acid and stearic acid salts have been chosen to model the ``tight`` carboxylic acids of immature fossil fuel feedstocks and have been pyrolyzed with an entrained flow reactor. Our preliminary results indicate that Group I and II salts yield primarily the parent acid. Benzoate salts also yield small amounts of benzene while the stearic acid salts give no other detectable products. In two alternative treatment strategies, esterification and anhydride preparation have also been accomplished with these compounds being subjected to the entrained flow reactor conditions. The benzoate esters give a number of products, such as benzaldehyde, benzene, and low MW gases. The formation of these compounds is extremely dependent on pyrolysis conditions and alkoxy chain length. A xenon flashlamp and an entrained flow reactor have been used to heat organic substrates to varying temperatures using different heating rates. Ultrarapid flashlamp pyrolysis (heating rate>10{sup 50}C/s) has been performed. Since the ultrarapid pyrolysis products differ from those observed with traditional heating techniques and differ from the products formed photochemically, the flashlamp pyrolysis products are attributed to high temperature thermal activation.

Penn, J.H.; Owens, W.H.

1991-01-01

28

Influence of Pyrolysis Temperature on Rice Husk Char Characteristics and Its Tar Adsorption Capability  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A biomass waste, rice husk, was inspected by thermoanalytical investigation to evaluate its capability as an adsorbent medium for tar removal. The pyrolysis process has been applied to the rice husk material at different temperatures 600, 800 and 1000 C with 20 C/min heating rate, to investigate two topics: (1) influence of temperature on characterization of rice husk char and; (2) adsorption capability of rice husk char for tar removal. The results showed that subsequent to high ...

Anchan Paethanom; Kunio Yoshikawa

2012-01-01

29

Pyrolysis of two agricultural residues: olive and grape bagasse. Influence of particle size and temperature  

Energy Technology Data Exchange (ETDEWEB)

The pyrolysis of olive and grape bagasse has been studied with the aim of determining the main characteristics of the charcoals formed and the nature and quantity of gases and liquids produced. Variables investigated were temperature between 300 and 900{sup o}C and particle size between 0.4 and 2 mm diameter. Experiments were carried out in an isothermal manner. As a general rule, particle size does not exert any influence, whereas temperature is a very significant variable. Thus an increase in this variable yields an increase in the fixed carbon content, gases produced and, to a lesser extent, ash percentage. On the other hand, volatile material and solid yields decrease with increasing temperature. The principal gases generated are H{sub 2}, CH{sub 4}, CO and CO{sub 2}, while among the liquid components the presence of methanol, acetone, furfuryl alcohol, phenol, furfural, naphthalene and o-cresol has to be highlighted. Heating values of both gas and solid phases were determined from gas composition and elemental carbon analysis. The quality of charcoals and heating value allow the conclusion that the most convenient temperature for the pyrolysis should be between 600 and 700{sup o}C, at which the production of liquids is at its maximum. Finally, a kinetic study of the pyrolysis, based on gas generation from thermal decomposition of residues, has been carried out. From this model, rate constants for the formation of each gas and their corresponding activation energies were determined. (author)

Encinar, J.M.; Beltran, F.J.; Bernalte, A.; Ramiro, A.; Gonzalez, J.F. [Universidad de Extremadura, Badajoz (Spain)

1996-12-31

30

Influence of temperature and particle size on the fixed bed pyrolysis of orange peel residues  

Energy Technology Data Exchange (ETDEWEB)

Orange peel is a residue from the production of juice. Its energetic valorisation could be interesting in areas where a different use, such as animal feed, is not possible. In order to investigate the viability of energy recovery, the pyrolysis of orange peel residues was studied in a fixed bed reactor, as an initial assessment of this process. The influence of pyrolysis temperature (300-600 C) and particle size (d{sub p}<300{mu}m and d{sub p}>800{mu}m) on product distribution, gas composition and char heating value has been investigated using a factorial design of experiments. Gas, char and water are the main products obtained; tar is only about 6 wt.% of the initial residue. Temperature was found to be the parameter which exerts a more important influence on the results than particle size. (author)

Aguiar, L. [Departamento de Mecanica, Universidad de Pinar del Rio, Cuba. Calle Marti 270, final, Pinar del Rio (Cuba); Marquez-Montesinos, F. [Departamento de Quimica, Universidad de Pinar del Rio, Cuba. Calle Marti 270, final, Pinar del Rio (Cuba); Gonzalo, A.; Sanchez, J.L.; Arauzo, J. [Thermochemical Processes Group (GPT), Aragon Institute for Engineering Research (I3A), University of Zaragoza, Maria de Luna 3, 50018 Zaragoza (Spain)

2008-09-15

31

Growth Temperature Effect on Carbon Nano tubes Formation by Spray Pyrolysis Method  

International Nuclear Information System (INIS)

Carbon nano tubes has been produced by using spray pyrolysis method with no carrier gas. Carbon nano tubes were formulated from a mixture a ferrocene and benzene with certain ratio and then the mixture were injected by the sprayer into the furnace. Growth temperature was optimized in the range of 650 until 850 oC to get the high quality of carbon nano tubes. These were characterized by Scanning Electron Microscope (SEM) and Energy Dispersive X-ray (EDX). (author)

2008-12-01

32

Biomass Pyrolysis: Comments on Some Sources of Confusions in the Definitions of Temperatures and Heating Rates  

Directory of Open Access Journals (Sweden)

Full Text Available Biomass pyrolysis is usually characterized on the basis of temperature and heating rate. Unfortunately, these parameters are badly defined in processing reactors as well as in laboratory devices. From the results of simplified models, the present paper points out the significant mistakes that can be made when assuming that the actual temperature and heating rate of reacting biomass particles are the same as those of the external heating medium. The difficulties in defining these two parameters are underlined in both cases of a heat source temperature supposed to be constant or to increase with time.

Jacques Ld

2010-04-01

33

Temperature dependence of ZnO rods produced by ultrasonic spray pyrolysis method  

International Nuclear Information System (INIS)

Zinc oxide (ZnO) microrods were prepared at different substrate temperatures by ultrasonic spray pyrolysis technique on glass substrates. The X-ray diffraction patterns show that obtained rods are composed of wurtzite-type and mainly grow along the [0 0 2] direction. Scanning electron microscope images show that the diameters of ZnO rods and the distances among the rods increase with increasing substrate temperature. In addition, the optical measurements reveal that transmittance and the band gap energies of films increase with increasing substrate temperature

2007-12-15

34

Pyrolysis characteristics of integrated circuit boards at various particle sizes and temperatures  

International Nuclear Information System (INIS)

A pyrolysis method was employed to recycle the metals and brominated compounds blended into printed circuit boards. This research investigated the effect of particle size and process temperature on the element composition of IC boards and pyrolytic residues, liquid products, and water-soluble ionic species in the exhaust, with the overall goal being to identify the pyrolysis conditions that will have the least impact on the environment. Integrated circuit (IC) boards were crushed into 5-40 mesh (0.71-4.4 mm), and the crushed particles were pyrolyzed at temperatures ranging from 200 to 500 deg. C. The thermal decomposition kinetics were measured by a thermogravimetric (TG) analyzer. The composition of pyrolytic residues was analyzed by Energy Dispersive X-ray Spectrometer (EDS), Inductively Coupled Plasma Atomic Emission Spectrometer (ICP-AES) and Inductively Coupled Plasma-Mass Spectrometry (ICP-MS). In addition, the element compositions of liquid products were analyzed by ICP-AES and ICP-MS. Pyrolytic exhaust was collected by a water-absorption system in an ice-bath cooler, and IC analysis showed that the absorbed solution comprised 11 ionic species. Based on the pyrolytic kinetic parameters of TG analysis and pyrolytic residues at various temperatures for 30 min, the effect of particle size was insignificant in this study, and temperature was the key factor for the IC board pyrolysis. Two stages of decomposition were found for IC board pyrolysis under nitrogen atmosphere. The activation energy was 38-47 kcal/mol for the first-stage reaction and 5.2-9.4 kcal/mol for the second-stage reaction. Metal content was low in the liquid by-product of the IC board pyrolysis process, which is an advantage in that the liquid product could be used as a fuel. Brominate and ammonium were the main water-soluble ionic species of the pyrolytic exhaust. A plan for their safe and effective disposal must be developed if the pyrolytic recycling process is to be applied to IC boards

2007-10-01

35

Pyrolysis characteristics of integrated circuit boards at various particle sizes and temperatures.  

Science.gov (United States)

A pyrolysis method was employed to recycle the metals and brominated compounds blended into printed circuit boards. This research investigated the effect of particle size and process temperature on the element composition of IC boards and pyrolytic residues, liquid products, and water-soluble ionic species in the exhaust, with the overall goal being to identify the pyrolysis conditions that will have the least impact on the environment. Integrated circuit (IC) boards were crushed into 5-40 mesh (0.71-4.4mm), and the crushed particles were pyrolyzed at temperatures ranging from 200 to 500 degrees C. The thermal decomposition kinetics were measured by a thermogravimetric (TG) analyzer. The composition of pyrolytic residues was analyzed by Energy Dispersive X-ray Spectrometer (EDS), Inductively Coupled Plasma Atomic Emission Spectrometer (ICP-AES) and Inductively Coupled Plasma-Mass Spectrometry (ICP-MS). In addition, the element compositions of liquid products were analyzed by ICP-AES and ICP-MS. Pyrolytic exhaust was collected by a water-absorption system in an ice-bath cooler, and IC analysis showed that the absorbed solution comprised 11 ionic species. Based on the pyrolytic kinetic parameters of TG analysis and pyrolytic residues at various temperatures for 30 min, the effect of particle size was insignificant in this study, and temperature was the key factor for the IC board pyrolysis. Two stages of decomposition were found for IC board pyrolysis under nitrogen atmosphere. The activation energy was 38-47 kcal/mol for the first-stage reaction and 5.2-9.4 kcal/mol for the second-stage reaction. Metal content was low in the liquid by-product of the IC board pyrolysis process, which is an advantage in that the liquid product could be used as a fuel. Brominate and ammonium were the main water-soluble ionic species of the pyrolytic exhaust. A plan for their safe and effective disposal must be developed if the pyrolytic recycling process is to be applied to IC boards. PMID:17467900

Chiang, Hung-Lung; Lin, Kuo-Hsiung; Lai, Mei-Hsiu; Chen, Ting-Chien; Ma, Sen-Yi

2007-10-01

36

Catalytic pyrolysis of waste rice husk over mesoporous materials.  

Science.gov (United States)

Catalytic fast pyrolysis of waste rice husk was carried out using pyrolysis-gas chromatography/mass spectrometry [Py-GC/MS]. Meso-MFI zeolite [Meso-MFI] was used as the catalyst. In addition, a 0.5-wt.% platinum [Pt] was ion-exchanged into Meso-MFI to examine the effect of Pt addition. Using a catalytic upgrading method, the activities of the catalysts were evaluated in terms of product composition and deoxygenation. The structure and acid site characteristics of the catalysts were analyzed by Brunauer-Emmett-Teller surface area measurement and NH3 temperature-programmed desorption analysis. Catalytic upgrading reduced the amount of oxygenates in the product vapor due to the cracking reaction of the catalysts. Levoglucosan, a polymeric oxygenate species, was completely decomposed without being detected. While the amount of heavy phenols was reduced by catalytic upgrading, the amount of light phenols was increased because of the catalytic cracking of heavy phenols into light phenols and aromatics. The amount of aromatics increased remarkably as a result of catalytic upgrading, which is attributed to the strong Brnsted acid sites and the shape selectivity of the Meso-MFI catalyst. The addition of Pt made the Meso-MFI catalyst even more active in deoxygenation and in the production of aromatics. PMID:22221540

Jeon, Mi-Jin; Kim, Seung-Soo; Jeon, Jong-Ki; Park, Sung Hoon; Kim, Ji Man; Sohn, Jung Min; Lee, See-Hoon; Park, Young-Kwon

2012-01-01

37

Catalytic pyrolysis of waste rice husk over mesoporous materials  

Science.gov (United States)

Catalytic fast pyrolysis of waste rice husk was carried out using pyrolysis-gas chromatography/mass spectrometry [Py-GC/MS]. Meso-MFI zeolite [Meso-MFI] was used as the catalyst. In addition, a 0.5-wt.% platinum [Pt] was ion-exchanged into Meso-MFI to examine the effect of Pt addition. Using a catalytic upgrading method, the activities of the catalysts were evaluated in terms of product composition and deoxygenation. The structure and acid site characteristics of the catalysts were analyzed by Brunauer-Emmett-Teller surface area measurement and NH3 temperature-programmed desorption analysis. Catalytic upgrading reduced the amount of oxygenates in the product vapor due to the cracking reaction of the catalysts. Levoglucosan, a polymeric oxygenate species, was completely decomposed without being detected. While the amount of heavy phenols was reduced by catalytic upgrading, the amount of light phenols was increased because of the catalytic cracking of heavy phenols into light phenols and aromatics. The amount of aromatics increased remarkably as a result of catalytic upgrading, which is attributed to the strong Brnsted acid sites and the shape selectivity of the Meso-MFI catalyst. The addition of Pt made the Meso-MFI catalyst even more active in deoxygenation and in the production of aromatics.

Jeon, Mi-Jin; Kim, Seung-Soo; Jeon, Jong-Ki; Park, Sung Hoon; Kim, Ji Man; Sohn, Jung Min; Lee, See-Hoon; Park, Young-Kwon

2012-01-01

38

Hydrogen production from biomass pyrolysis gas via high temperature steam reforming process  

International Nuclear Information System (INIS)

Full text: The aim of this work has been undertaken as part of the design of continuous hydrogen production using the high temperature steam reforming process. The steady-state test condition was carried out using syngas from biomass pyrolysis, whilst operating at high temperatures between 600 and 1200 degree Celsius. The main reformer operating parameters (e.g. temperature, resident time and steam to biomass ratio (S/B)) have been examined in order to optimize the performance of the reformer. The operating temperature is a key factor in determining the extent to which hydrogen production is increased at higher temperatures (900 -1200 degree Celsius) whilst maintaining the same as resident time and S/B ratio. The effects of exhaust gas composition on heating value were also investigated. The steam reforming process produced methane (CH4) and ethylene (C2H4) between 600 to 800 degree Celsius and enhanced production ethane (C2H6) at 700 degree Celsius. However carbon monoxide (CO) emission was slightly increased for higher temperatures all conditions. The results show that the use of biomass pyrolysis gas can produce higher hydrogen production from high temperature steam reforming. In addition the increasing reformer efficiency needs to be optimized for different operating conditions. (author)

2010-07-26

39

Prediction of sulphur distribution in products during low temperature coal pyrolysis and gasification  

Energy Technology Data Exchange (ETDEWEB)

During devolatilization of coal, the sulphur present is distributed into solid liquid, and gaseous products depending on the type and quantity of the sulphur and the processing conditions (e.g., temperature, pressure, and heating rate) used. In this study, a series of coals (mainly high volatile bituminous) was devolatilized at a relatively low temperature (500{degree}C) in a fixed-bed reactor in an inert atmosphere. The distribution of sulphur in solid, liquid, and gaseous products was monitored. Influence of peak devolatilization temperature on sulphur distribution in products was determined for a high volatile bituminous coal (Pittsburgh No. 8). The sulphur content of the pyrolysis liquids generated at 500{degree}C correlates well with the total coal sulphur. The total sulphur of the char can be correlated with the pyritic sulphur content of the coal. Total gaseous sulphur content (sum of H{sub 2}S and COS) or sulphur content of tar increases with increase in organic sulphur of coal, and relatively good correlations were obtained. An increase in pyrolysis temperature increases the total gaseous sulphur yield at the expense of char sulphur. Based on sulphur distribution data for 32 bituminous coals, equations have been developed to correlate the sulphur yield in products with the total sulphur of the feed coal. The correlations developed in this study are expected to be applicable for predicting the sulphur distribution in products during conversion of bituminous coals using low temperature pyrolysis technology, and to estimate sulphur products in the exit gases and tars when coal is converted in a fixed-bed gasifier in which initial devolatilization occurs at a relatively low temperature. 36 refs., 6 figs., 9 tabs.

Khan, M.R. (Texaco Inc., Beacon, NY (USA). Texaco Research Center)

1989-11-01

40

Toluene pyrolysis studies and high temperature reactions of propargyl chloride  

Energy Technology Data Exchange (ETDEWEB)

The main focus of this program is to investigate the thermal decompositions of fuels that play an important role in the pre-particle soot formation process. It has been demonstrated that the condition of maximum soot yield is established when the reaction conditions of temperature and pressure are sufficient to establish a radical pool to support the production of polyaromatic hydrocarbon species and the subsequent formation of soot particles. However, elevated temperatures result in lower soot yields which are attributed to thermolyses of aromatic ring structures and result in the bell-shaped dependence of soot yield on temperature. The authors have selected several acyclic hydrocarbons to evaluate the chemical thermodynamic and kinetic effects attendant to benzene formation. To assess the thermal stability of the aromatic ring, the authors have studied the pyrolyses of benzene, toluene, ethylbenzene, chlorobenzene and pyridine. Time-of-flight mass spectrometry (TOF) is employed to analyze the reaction zone behind reflected shock waves. Reaction time histories of the reactants, products, and intermediates are constructed and mechanisms are formulated to model the experimental data. The TOF work is often performed with use of laser schlieren densitometry (LS) to measure density gradients resulting from the heats of various reactions involved in a particular pyrolytic system. The two techniques, TOF and LS, provide independent and complementary information about ring formation and ring rupture reactions.

Kern, R.D.; Chen, H.; Qin, Z. [Univ. of New Orleans, LA (United States)

1993-12-01

 
 
 
 
41

Influence of fast pyrolysis temperature on biochar labile fraction and short-term carbon loss in a loamy soil  

DEFF Research Database (Denmark)

Production of bio-oil, gas and biochar from pyrolysis of biomass is considered a promising technology for combined production of bioenergy and recalcitrant carbon (C) suitable for sequestration in soil. Using a fast pyrolysis centrifuge reactor (PCR) the present study investigated the relation between fast pyrolysis of wheat straw at different reactor temperatures and the short-term degradability of biochar in soil. After 115 days incubation 3??12% of the added biochar-C had been emitted as CO2. On average, 90% of the total biochar-C loss occurred within the first 20 days of the experiment, emphasizing the importance of knowing the biochar labile fraction when evaluating a specific biochars C sequestration potential. The pyrolysis temperature influenced the outputs of biochar, bio-oil and syngas significantly, as well as the stability of the biochar produced. Contrary to slow pyrolysis a fast pyrolysis process may result in incomplete conversion of biomass due to limitations to heat transfer and kinetics. In our case chemical analysis of the biochars revealed unconverted cellulosic and hemicellulosic fractions, which in turn were found to be proportional with the short-term biochar degradation in soil. As these labile carbohydrates are rapidly mineralized, their presence lowers the biochar-C sequestration potential. By raising the pyrolysis temperature, biochar with none or low contents of these fractions can be produced, but this will be on the expense of the biochar quantity. The yield of CO2 neutral bio-oil is the other factor to optimize when adjusting the pyrolysis temperature settings to give the overall greatest climate change mitigation effect.

Bruun, Esben; Hauggaard-Nielsen, Henrik

2011-01-01

42

Influence of Biomass Pyrolysis Temperature, Heating Rate and Type of Biomass on Produced Char in a Fluidized Bed Reactor  

Directory of Open Access Journals (Sweden)

Full Text Available Biomass pyrolysis experiments were carried out in a fluidized bed reactor (FBR and produced char yields were measured for 3 kinds of softwoods, 3 kinds of hardwoods, 2 kinds of herbaceous plants and 3 kinds of agricultural residues. Pyrolysis temperature range was between 300 C and 1200 C, and heating rate was fast (1001000 C/s or slow (10 C/min. After the pyrolysis, produced char was collected with bed particles and only the char was separated from bed particles by sieving. Surface of the produced char was observed by SEM to confirm bed particles adhesion behavior on the surface of char. Char-bed particles (alumina particles adhesion were observed mainly under fast pyrolysis condition for most of the biomass samples. Char yields by fast pyrolysis were much lower than those by slow pyrolysis of Eucalyptus camaldulensis (hardwood, Japanese cypress (softwood, Switchgrass (herbaceous plant and Bagasse (agricultural residue, respectively. In the case of fast pyrolysis condition, char yields from softwood species were lower than those from other biomass species.

Toshiyuki Iwasaki

2014-05-01

43

Influence of pyrolysis temperature on characteristics and heavy metal adsorptive performance of biochar derived from municipal sewage sludge.  

Science.gov (United States)

To investigate systematically the influence of pyrolysis temperature on properties and heavy metal adsorption potential of municipal sludge biochar, biophysical dried sludge was pyrolyzed under temperature varying from 500C to 900C. The biochar yield decreased with the increase in pyrolysis temperature, while the ash content retained mostly, thus transforming the biochars into alkaline. The structure became porous as the temperature increased, and the concentrations of surface functional group elements remained low. Despite the comparatively high content of heavy metal in the biochar, the leaching toxicity of biochars was no more than 20% of the Chinese standard. In the batch experiments of cadmium(II) adsorption, the removal capacity of biochars improved under higher temperature, especially at 800C and 900C even one order of magnitude higher than that of the commercial activated carbon. For both energy recovery and heavy metal removal, the optimal pyrolysis temperature is 900C. PMID:24835918

Chen, Tan; Zhang, Yaxin; Wang, Hongtao; Lu, Wenjing; Zhou, Zeyu; Zhang, Yuancheng; Ren, Lulu

2014-07-01

44

Influence of Pyrolysis Temperature and Heating Rate in the Fabrication of Carbon Membrane: A Review  

Directory of Open Access Journals (Sweden)

Full Text Available Despite its brittleness and relatively high fabrication cost, the excellent performance of carbon membrane in gas separation outweighs such limitations. The carbon-based membranes have the capability to perform specific gas separations when compared to other types of membranes or any conventional separation technology that based on cryogenic, adsorption or absorption mechanisms. Basically, carbon membrane is a derivation of its polymeric precursor membrane. The derivation refers to the pyrolysis process of the polymeric membrane that turns it into a carbon membrane. During the process, the polymeric membrane undergoes a controlled thermal treatment and at the same time, inert atmosphere is continuously generated to remove any oxidizing agents. This process is proven to be highly critical and challenging because it determines the final pore structure and its corresponding performances of the carbon membrane. Heating rate and pyrolysis temperature are part of the pyrolysis process and the most tuned parameters to obtain a very fine carbon membrane according to an intended application-based performance. These parameters have been reported numerously for their significant impacts on the fabrication of carbon membranes and this paper provides the review.

M.A.T. Jaya

2014-01-01

45

Formation of PAH and soot during acetylene pyrolysis at different gas residence times and reaction temperatures  

International Nuclear Information System (INIS)

The formation of polycyclic aromatic hydrocarbons (PAH) and soot from the pyrolysis of acetylene was studied, taking into account the influence of the operating conditions, such as gas residence time and temperature. The influence of gas residence time was considered between 1.28 and 3.88 s for the experiments carried out under different temperatures from 1073 to 1223 K. The total PAH was calculated as the addition of PAH concentration found in different locations, namely adsorbed on soot and on the reactor walls, and at the outlet gas stream. The relationship between the PAH concentrations and their carcinogenic equivalence sum (KE) was also evaluated. The results obtained showed that temperature and residence time have a high influence on pyrolysis products, especially on the PAH concentration adsorbed on soot, which exhibited the highest KE in all cases studied. -- Highlights: ? This study analyses the influence of gas residence time and reaction temperature on PAH and soot formation. ? The present work develops an analytical method for PAH-priorities quantification. ? A major amount of PAH adsorbed on soot is found under every evaluated condition. ? High PAH concentration does not necessarily involve more dangerous effects.

2012-07-01

46

Low substrate temperature synthesis of carbon nanowalls by ultrasonic spray pyrolysis  

Energy Technology Data Exchange (ETDEWEB)

In this paper, we report the synthesis of two-dimensional wall like carbon nanostructures (i.e. carbon nanowalls) by ultrasonic spray pyrolysis of ethanol and fullerene mixture. At higher temperature carbon nanofibers were formed on the substrate placed at the center of the reactor tube, whereas carbon nanowalls were observed on the substrate placed downstream of the tube below 100 {sup o}C. Spaces between the nanowalls changed with distance of the substrates from the furnace. Qualitative analysis of materials was performed using scanning electron microscopy, transmission electron microscopy and Raman spectroscopy.

Zhang Jianhui [Department of Frontier Materials, Nagoya Institute of Technology, Nagoya 466-8555 (Japan); Khatri, Ishwor, E-mail: ishwor_nep2000@yahoo.co [Department of Frontier Materials, Nagoya Institute of Technology, Nagoya 466-8555 (Japan); Kishi, Naoki [Department of Frontier Materials, Nagoya Institute of Technology, Nagoya 466-8555 (Japan); Mominuzzaman, Sharif M. [Department of Electrical and Electronic Engineering, Bangladesh University of Engineering and Technology, Dhaka 1000 (Bangladesh); Soga, Tetsuo; Jimbo, Takashi [Department of Frontier Materials, Nagoya Institute of Technology, Nagoya 466-8555 (Japan)

2011-04-29

47

Temperature and time effect on the concentrations of free radicals in coal: Evidence from laboratory pyrolysis experiments  

Energy Technology Data Exchange (ETDEWEB)

The relationships between free radical concentration (N{sub g}) and vitrinite reflectance (%R{sub o}) of coal were tested through 36 laboratory anhydrous pyrolysis experiments. The experiments were carried out at isothermal reactor with pyrolysis temperatures ranging from 300 to 550 {sup o}C over 30-480 min. The effects of temperature and retention time on the N{sub g} were investigated. The concentrations of free radicals in pyrolysis coal samples increase with increasing time and temperature of experiments and reach a maximum value at about 1.75 %R{sub o}, and then decrease with further maturation. The Temperature Time Index (TTI) integral equation was applied to establish the relationship between the TTI and N{sub g} in this paper. As the free radical concentration in organic matter is strongly maturity dependent, it may prove to be a valuable geothermometer for paleogeotemperature study in sedimentary basins. (author)

Qiu, Nansheng; Li, Huili; Zhu, Yinkang [Key Laboratory for Hydrocarbon Accumulation Mechanism, Ministry of Education, Beijing 102249 (China); Jin, Zhijun [Instittute of Petroleum Exploration and Development, SINOPEC, Beijing 100083 (China)

2007-02-01

48

Substitution of fossil fuels by using low temperature pyrolysis of agricultural residues  

International Nuclear Information System (INIS)

Externally heated rotary kiln pyrolysis reactor is used as a new process technology for the conversion of biomass into useful primary energy products. A 3 MW pyrolysis pilot plant is being operated for a period of two years using agricultural residues. Several analytical methods are applied to provide an insight into the complex process of pyrolysis. Fundamentals for an advanced pyrolysis model approach will be obtained by the results of the pilot plant. (author)

2010-07-26

49

Catalytic deoxygenation of unsaturated renewable feedstocks for production of diesel fuel hydrocarbons  

Energy Technology Data Exchange (ETDEWEB)

The liquid-phase deoxygenation reaction of unsaturated renewables has been investigated in a semi-batch reactor. The reactants examined were the monounsaturated fatty acid, oleic acid, the diunsaturated fatty acid, linoleic acid and the monounsaturated fatty acid ester, methyl oleate. The reactions were carried out over a Pd/C catalyst under constant pressure and temperature in the following domain, 15-27 bar and 300-360{sup o}C, respectively. The influence of carrier gas was additionally investigated. The impact as solvent (mesitylene) was studied as well and reaction pathways were proposed. Furthermore, continuous deoxygenation experiments were conducted, facilitating understanding of the catalyst stability and catalyst deactivation. The deoxygenation catalyst was characterized by physisorption, temperature programmed desorption (TPD), thermogravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). 38 refs., 19 figs., 7 tabs.

M. Snare; I. Kubickova; P. Maeki-Arvela; D. Chichova; K. Eraenen; D.Yu. Murzin [Aabo Akademi University, Aabo-Turku (Finland). Laboratory of Industrial Chemistry, Process Chemistry Centre

2008-05-15

50

Temperature dependence of Fluorine-doped tin oxide films produced by ultrasonic spray pyrolysis  

International Nuclear Information System (INIS)

Fluorine-doped tin oxide (FTO) films were prepared at different substrate temperatures by ultrasonic spray pyrolysis technique on glass substrates. Among F-doped tin oxide films, the lowest resistivitiy was found to be 6.2 x 10-4 ?-cm for a doping percentage of 50 mol% of fluorine in 0.5 M solution, deposited at 400 oC. Hall coefficient analyses and secondary ion mass spectrometry (SIMS) measured the electron carrier concentration that varies from 3.52 x 1020 cm-3 to 6.21 x 1020 cm-3 with increasing fluorine content from 4.6 x 1020 cm-3 to 7.2 x 1020 cm-3 in FTO films deposited on various temperatures. Deposition temperature on FTO films has been optimized for achieving a minimum resistivity and maximum optical transmittance.

2009-12-15

51

Pyrolysis behaviors of wood and its constituent polymers at gasification temperature  

Energy Technology Data Exchange (ETDEWEB)

Pyrolysis behavior of wood at gasification temperature (800 C) was investigated focusing on the behaviors of the wood constituent polymers [cellulose, hemicellulose (glucomannan and xylan) and lignin (milled wood lignin)]. Tar compositions (iso-propanol-soluble and water-soluble tar fractions), which were characterized with GPC, GC-MS, GC-FID (oxime-TMS analysis), capillary electrophoresis and {sup 1}H NMR analysis, were quite different between wood polysaccharides and lignin. Furthermore, comparison of the tar- and secondary char-forming behaviors indicated that comparatively stable primary tar from wood polysaccharides undergo secondary reactions including carbonization after condensation at the reactor wall with lower temperature than their boiling points, while that primary tar from lignin is more reactive to give the vapor phase carbonization products during volatilization. (author)

Hosoya, T.; Kawamoto, H.; Saka, S. [Graduate School of Energy Science, Kyoto University, Yoshida-honmachi, Sakyo-ku, Kyoto 606-8501 (Japan)

2007-03-15

52

High temperature pyrolysis: A new system for isotopic and elemental analysis  

International Nuclear Information System (INIS)

A new method for the automated sample conversion and on-line determination of deuterium, carbon, nitrogen and oxygen isotopes for organic and inorganic substances is presented. The samples are pyrolytically decomposed in presence of reactive carbon in a high temperature pyrolysis system (HTP) at a temperature higher than 1400 deg. C. The method has a great potential for the analysis of hydrogen, carbon, nitrogen and oxygen stable isotopes ratios. The instrumentation and application is very simple and cost effective. The reproducibility of the ?-values is 3 per mille for D/H, 0.3 per mille for "1"8O, and 0.2 per mille for "1"3C and "1"5N respectively. The system is suitable for solid, liquid and gaseous samples. Results are presented for the isotopic composition of international reference materials which show the precision and accuracy of the method. (author)

2001-10-01

53

RELATION BETWEEN MECHANICAL PROPERTIES AND PYROLYSIS TEMPERATURE OF PHENOL FORMALDEHYDE RESIN FOR GAS SEPARATION MEMBRANES  

Directory of Open Access Journals (Sweden)

Full Text Available The aim of this paper has been to characterize the relation between the pyrolysis temperature of phenol-formaldehyde resin, the development of a porous structure, and the mechanical properties for the application of semipermeable membranes for gas separation. No previous study has dealt with this problem in its entirety. Phenol-formaldehyde resin showed an increasing trend toward micropore porosity in the temperature range from 500 till 1000C, together with closure of mesopores and macropores. Samples cured and pyrolyzed at 1000C pronounced hysteresis of desorption branch. The ultimate bending strength was measured using a four-point arrangement that is more suitable for measuring of brittle materials. The chevron notch technique was used for determination the fracture toughness. The results for mechanical properties indicated that phenol-formaldehyde resin pyrolyzates behaved similarly to ceramic materials. The data obtained for the material can be used for calculating the technical design of gas separation membranes.

MONIKA UPOV

2012-03-01

54

Low temperature pyrolysis of coal or oil shale in the presence of calcium compounds  

Energy Technology Data Exchange (ETDEWEB)

A coal pyrolysis technique or process is described in which particulate coal is pyrolyzed in the presence of about 5 to 21 wt. % of a calcium compound selected from calcium oxide, calcined (hydrate) dolomite, or calcined calcium hydrate to produce a high quality hydrocarbon liquid and a combustible product gas which are characterized by low sulfur content. The pyrolysis is achieved by heating the coal-calcium compound mixture at a relatively slow rate at a temperature of about 450.degree. to 700.degree. C. over a duration of about 10 to 60 minutes in a fixed or moving bed reactor. The gas exhibits an increased yield in hydrogen and C.sub.1 -C.sub.8 hydrocarbons and a reduction in H.sub.2 S over gas obtainable by pyrolyzing cola without the calcium compound. The liquid product obtained is of a sufficient quality to permit its use directly as a fuel and has a reduced sulfur and oxygen content which inhibits polymerization during storage.

Khan, M. Rashid (Morgantown, WV)

1988-01-01

55

Flash pyrolysis at high temperature of ligno-cellulosic biomass and its components - production of synthesis gas  

International Nuclear Information System (INIS)

Pyrolysis is the first stage of any thermal treatment of biomass and governs the formation of synthesis gas for the production of electricity, hydrogen or liquid fuels. The objective of this work is to establish a link between the composition of a biomass and its pyrolysis gas. We study experimental flash pyrolysis and fix the conditions in which quantities of gas are maximal, while aiming at a regime without heat and mass transfer limitations (particles about 100 ?m): temperature of 950 C and residence time of about 2 s. Then we try to predict gas yields of any biomass according to its composition, applicable in this situation where thermodynamic equilibrium is not reached. We show that an additivity law does not allow correlating gas yields of a biomass with fractions of cellulose, hemi-cellulose and lignin contained in this biomass. Several explanations are suggested and examined: difference of pyrolytic behaviour of the same compound according to the biomass from which it is extracted, interactions between compounds and influence of mineral matter. With the aim of industrial application, we study pyrolysis of millimetric and centimetric size particles, and make a numerical simulation of the reactions of pyrolysis gases reforming. This simulation shows that the choice of biomass affects the quantities of synthesis gas obtained. (author)

2007-01-01

56

Pyrolysis and gasification of coal at high temperatures. Quarterly progress report No. 11, March 15, 1990--June 15, 1990  

Energy Technology Data Exchange (ETDEWEB)

We made considerable progress towards completing the development of a thermogravimetric reactor with video microscopy imaging capabilities (TGA/VMI). The video micrOSCOPY components were designed, installed and are currently under testing. With the newly developed TGA/VNH apparatus we can directly observe macroscopic changes in the morphology of pyrolyzing particles and thermal ignitions of burning particles while simultaneously monitoring the weight of pyrolyzing or reacting samples. The systematic investigation on the effects of pyrolysis conditions and char macropore structure on char reactivity continued. Pyrolysis and gasification experiments were performed consecutively in our TGA reactor and the char reactivity patterns were measured for a wide range of temperatures (400--600{degrees}C). These conditions cover both the kinetic and the diffusion limited regimes. Our results show conclusively that chars produced at high pyrolysis heating rates (and, therefore, having a more open cellular macropore structure) are more reactive and ignite more easily than chars pyrolyzed at low heating rates. These results have been explained using theoretical models. We also investigated for the first time the effect of coal particle size and external mass transfer limitations on the reactivity patterns and ignition behavior of char particles combusted in air. Finally, we used our hot stage reactor to monitor the structural transformations occurring during pyrolysis via a video microscopy system. Pyrolysis experiments were videotaped and particle swelling and the particle ignitions were determined and analyzed using digitized images from these experiments.

Zygourakis, K.

1990-12-31

57

Low oxygen biomass-derived pyrolysis oils and methods for producing the same  

Energy Technology Data Exchange (ETDEWEB)

Low oxygen biomass-derived pyrolysis oils and methods for producing them from carbonaceous biomass feedstock are provided. The carbonaceous biomass feedstock is pyrolyzed in the presence of a catalyst comprising base metal-based catalysts, noble metal-based catalysts, treated zeolitic catalysts, or combinations thereof to produce pyrolysis gases. During pyrolysis, the catalyst catalyzes a deoxygenation reaction whereby at least a portion of the oxygenated hydrocarbons in the pyrolysis gases are converted into hydrocarbons. The oxygen is removed as carbon oxides and water. A condensable portion (the vapors) of the pyrolysis gases is condensed to low oxygen biomass-derived pyrolysis oil.

Marinangeli, Richard; Brandvold, Timothy A; Kocal, Joseph A

2013-08-27

58

Pyrolysis studies of organic oxygenates 3. High temperature rearrangement of aryl alkyl ethers  

Energy Technology Data Exchange (ETDEWEB)

Thermal chemistry pathways of aryl alkyl ethers have been investigated under coal conversion-like conditions. Anisole is a thermally reactive compound having an oxygen functionality found in such coal precursors as lignins. Pyrolysis of anisoles was carried out using small batch autoclaves. Under thermolysis conditions anisole yielded a product distribution strongly dependent upon experimental parameters. Phenol, methane, CO and benzaldehyde are the low molecular weight products and polyphenyls and polyethers are the predominant high molecular weight products. The generation of CO is explained by a high temperature rearrangement of the phenyl group from O- to C- followed by rapid thermal decarbonylation of the benzaldehyde. Carbon monoxide formation from aryl alkyl ether can thus be an important mechanistic pathway in coal conversion processes. By investigating the rearrangement using para-fluoroanisole it was shown that this rearrangement proceeds via a threecentered intermediate to para-fluorobenzaldehyde. No meta isomer was observed.

Schlosberg, R.H.; Ashe, T.R.; Danik, J.A.; Dupre, G.D.; Kurs, A.; Olmstead, W.N.; Szajowski, P.F.

1983-06-01

59

Deoxygenation of the Baltic Sea during the last century  

Science.gov (United States)

Deoxygenation is a global problem in coastal and open regions of the ocean, and has led to expanding areas of oxygen minimum zones and coastal hypoxia. The recent expansion of hypoxia in coastal ecosystems has been primarily attributed to global warming and enhanced nutrient input from land and atmosphere. The largest anthropogenically induced hypoxic area in the world is the Baltic Sea, where the relative importance of physical forcing versus eutrophication is still debated. We have analyzed water column oxygen and salinity profiles to reconstruct oxygen and stratification conditions over the last 115 y and compare the influence of both climate and anthropogenic forcing on hypoxia. We report a 10-fold increase of hypoxia in the Baltic Sea and show that this is primarily linked to increased inputs of nutrients from land, although increased respiration from higher temperatures during the last two decades has contributed to worsening oxygen conditions. Although shifts in climate and physical circulation are important factors modulating the extent of hypoxia, further nutrient reductions in the Baltic Sea will be necessary to reduce the ecosystems impacts of deoxygenation.

Carstensen, Jacob; Andersen, Jesper H.; Gustafsson, Bo G.; Conley, Daniel J.

2014-01-01

60

Deoxygenation of the Baltic Sea during the last century.  

Science.gov (United States)

Deoxygenation is a global problem in coastal and open regions of the ocean, and has led to expanding areas of oxygen minimum zones and coastal hypoxia. The recent expansion of hypoxia in coastal ecosystems has been primarily attributed to global warming and enhanced nutrient input from land and atmosphere. The largest anthropogenically induced hypoxic area in the world is the Baltic Sea, where the relative importance of physical forcing versus eutrophication is still debated. We have analyzed water column oxygen and salinity profiles to reconstruct oxygen and stratification conditions over the last 115 y and compare the influence of both climate and anthropogenic forcing on hypoxia. We report a 10-fold increase of hypoxia in the Baltic Sea and show that this is primarily linked to increased inputs of nutrients from land, although increased respiration from higher temperatures during the last two decades has contributed to worsening oxygen conditions. Although shifts in climate and physical circulation are important factors modulating the extent of hypoxia, further nutrient reductions in the Baltic Sea will be necessary to reduce the ecosystems impacts of deoxygenation. PMID:24706804

Carstensen, Jacob; Andersen, Jesper H; Gustafsson, Bo G; Conley, Daniel J

2014-04-15

 
 
 
 
61

Catalytic deoxygenation of liquid biomass for hydrocarbon fuels  

Energy Technology Data Exchange (ETDEWEB)

Liquid biomass such as methyl laurate and canola oil is deoxygenated with hydrogen and NiMo/{gamma}-Al{sub 2}O{sub 3} catalyst. Oxygen from methyl laurate and canola oil is removed at 18.25-85.13 bar initial cold hydrogen pressure and 300-400 C, using a 316 stainless steel batch reactor. Removal of oxygen from liquid methyl laurate and canola oil is evaluated with a GC/MS analyzer for liquid reaction products and another GC for gaseous reaction products. The range of reaction duration of liquid biomass in the batch reactor is 30-60 min under the deoxygenation conditions. Conversion of liquid biomass into gaseous products is evaluated with analysis data of gas products and a mass balance in terms of hydrogen. The objective of this research is to develop an efficient method of removing oxygen from liquid biomass to produce petroleum-comparative liquid hydrocarbons with hydrogen and a catalyst. Removal of oxygen from bio-based fuels for liquid hydrocarbon fuel is needed to increase its energy intensity, stability, and decrease its viscosity. In this paper, removal of oxygen from methyl laurate and canola oil is discussed in detail in terms of various oxygen removal conditions such as reaction temperature and pressure, catalyst amount, and hydrodynamics of heterogeneous reaction mixture in the batch reactor. (author)

Kwon, Kyung C. [Chemical Engineering Department, Tuskegee University, Tuskegee, AL 36088 (United States); Mayfield, Howard [AFRL, Tyndall Air Force, Panama City, Florida (United States); Marolla, Ted [AFRL, Tyndall Air Force, Panama City, Florida (United States); Applied Research Associates, Inc, Panama City, Florida (United States); Nichols, Bob [Applied Research Associates, Inc, Panama City, Florida (United States); Mashburn, Mike [Physics Department, Florida State University, Tallahassee, Florida (United States)

2011-03-15

62

Deoxygenation of Lake Ikeda, Japan  

Science.gov (United States)

Lake Ikeda (Kagoshima prefecture, Japan) is a deep lake with a maximum depth of 233 m. Monitoring data of lake Ikeda exist since 1975. We have analyzed the long-term variability in the water conditions of Lake Ikeda. Recently, Lake Ikeda has exhibited the phenomenon of incomplete overturning because of climate warming. The concentrations of DO (dissolved oxygen) in the deepest parts of the lake have reduced. This phenomenon was observed to have started in the 1980s, and gradually, the deepest parts of the lake became anoxic. Later, the anoxic layer became thicker. Currently, winter mixing in Lake Ikeda reaches to depths of only 100 m. According to our simple estimation, the total volume of oxygen in Lake Ikeda will reduce from approximately 70% in the mid-1980s to 40% by the end of 2010. In addition to this phenomenon, the oxygen concentration appears to vary with several years oscillations. The depths to which mixing occurs depends on the severity of the winter, such as the air temperature during the winter season. The mixing period generally occurs in February; hence, the limnological year is considered to start in February. During our analysis period, the total DO mass showed high values in 1996, 2001, and 2003. Air temperature data obtained for regions near Lake Ikeda (the station name is Ibusuki) are used to clarify the cause of the high DO mass values in the three abovementioned years. During the period prior to the occurrence of the high DO mass in February 1996, i.e., in December 1995 and January 1996, the air temperature was low. Similarly, in 2001 and 2003, the air temperature was low in January (one month before the high DO mass was observed). In January 2001 and 2003, the AO (Atlantic Oscillation) index was negative. When the AO index is negative, there tends to be a greater movement of cold polar air into mid-latitudinal regions including Japan (Yamakawa, 2005). This movement induced a low air temperature in Ibusuki, and consequently, a high DO mass was observed in Lake Ikeda. On the other hand, the AO index was negative in December 1995 and January 1996. In addition, the WP (Western Pacific) index was also negative in the winter of 1995/96. When the WP index is negative, Japan experiences a cold winter (Koide and Kodera, 1999; Yasunaka and Hanawa, 2008). Therefore, the combination of the negative phase of AO and the negative phase of WP led to the occurrence of cold surges near Lake Ikeda, which in turn resulted in the high DO mass in February 1996. When DO concentration in the deep layer of the lake becomes higher caused winter mixing, we observe also a reduction in the DO concentration in the surface layer. The DO concentration in the surface layer sometimes decreased to 70%. In future, once Lake Ikeda will deep mixing during very cold winters, the DO concentration in the surface water might reduce largely.

Nagata, R.; Hasegawa, N.

2010-12-01

63

Evaluation of Integrated Time-Temperature Effect in Pyrolysis Process of Historically Contaminated Soils with Cadmium (Cd and Lead (Pb  

Directory of Open Access Journals (Sweden)

Full Text Available It is already known that heavy metals pollution causes important concern to human and ecosystem health. Heavy metals in soils at the European level represents 37.3% between main contaminates affecting soils (EEA, 2007. This paper illustrates results obtained in the framework of laboratory experiments concerning the evaluation of integrated time-temperature effect in pyrolysis process applied to contaminated soil by two different ways: it is about heavy metals historically contaminated soil from one of the most polluted areas within Romania, and artificially contaminated with PCB-containing transformer oil. In particular, the authors focused on a recent evaluation of pyrolysis efficiency on removing lead (Pb and cadmium (Cd from the contaminated soil. The experimental study evaluated two important parameters related to the studied remediation methodology: thermal process temperature and the retention time in reactor of the contaminated soils. The remediation treatments were performed in a rotary kiln reactor, taking into account three process temperatures (400C, 600C and 800C and two retention times: 30 min. and 60 min. Completed analyses have focused on pyrolysis solids and gas products. Consequently, both ash and gas obtained after pyrolysis process were subjected to chemical analyses.

Bulm?u C

2013-04-01

64

Catalytic Oxidation and Deoxygenation of Renewables with Rhenium Complexes  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Transformation of renewables has received major research interest in recent years, opening up completely new research areas, in particular in the field of oxidation and deoxygenation. For the oxidation reaction, rhenium complexes, in particular methyltrioxorhenium, are well known for their potential as catalysts, but they are also potent catalysts for the deoxygenation reaction. The application of organometallic rhenium complexes in both the oxidation and deoxygenation reactions using a broad...

Korstanje, T. J.; Klein Gebbink, R. J. M.

2012-01-01

65

Flame Temperature Effect on the Structure of SiC Nanoparticles Grown by Laser Pyrolysis  

Energy Technology Data Exchange (ETDEWEB)

Small SiC nanoparticles (10 nm diameter) have been grown in a flow reactor by CO{sub 2} laser pyrolysis from a C{sub 2}H{sub 2} and SiH{sub 4} mixture. The laser radiation is strongly absorbed by SiH{sub 4} vibration. The energy is transferred to the reactive medium and leads to the dissociation of molecules and the subsequent growth of the nanoparticles. The reaction happens with a flame. The purpose of the experiments reported in this paper is to limit the size of the growing particles to the nanometric scale for which specific properties are expected to appear. Therefore the effects of experimental parameters on the structure and chemical composition of nanoparticles have been investigated. For a given reactive mixture and gas velocity, the flame temperature is governed by the laser power. In this study, the temperature was varied from 875 deg. C to 1100 deg. C. The chemical analysis of the products indicate that their composition is a function of the temperature. For the same C/Si atomic ratio in the gaseous phase, the C/Si ratio in the powder increases from 0.7 at 875 deg. C up to 1.02 at 1100 deg. C, indicating a growth mechanism limited by C{sub 2}H{sub 2} dissociation. As expected, X-ray diffraction has shown an improved crystallisation with increasing temperature. Transmission electron microscopy observations have revealed the formation of 10 nm grains for all values of laser power (or flame temperature). These grains appear amorphous at low temperature, whereas they contain an increasing number of nanocrystals (2 nm diameter) when the temperature increases. These results pave the way to a better control of the structure and chemical composition of laser synthesised SiC nanoparticles in the 10 nm range.

Herlin-Boime, N. [Laboratoire Francis Perrin (CEA-CNRS URA 2453), CEA Saclay, Service des Photons, Atomes et Molecules (France)], E-mail: herlin@drecam.cea.fr; Vicens, J.; Dufour, C. [Laboratoire d' Etudes et de Recherches sur les Materiaux (LERMAT) (CNRS 2139), ENSICAEN (France); Tenegal, F.; Reynaud, C. [Laboratoire Francis Perrin (CEA-CNRS URA 2453), CEA Saclay, Service des Photons, Atomes et Molecules (France); Rizk, R. [Laboratoire d' Etudes et de Recherches sur les Materiaux (LERMAT) (CNRS 2139), ENSICAEN (France)

2004-02-15

66

Effect of temperature during the spray pyrolysis synthesis of silver nanopowder  

International Nuclear Information System (INIS)

We report the results of the synthesis and characterization of Ag, AgO, AgNO3 nanopowders or mixtures of them, obtained by spray pyrolysis technique. An aqueous solution of AgNO3 with a concentration of 0.2 mol/L was sprayed through a horizontal tubular furnace where the solvent was evaporated and pyrolytic reaction occurs producing AgNO3, AgO and Ag particles. The synthesis was made at 500, 600 and 700 oC. The obtained material was analyzed by Transmission Electron Microscopy, and the optimal temperature to obtain particles of around 10 nm was 600 oC. The X-rays and Electron Diffraction analysis determined the coexistence of the phases of Ag, AgO and AgNO3, whereas the measurement of x-rays fluorescence the presence of Ag was detected. The solution concentration and the carrier flow, the temperature and the temperature gradient in the furnace influence in the phase and size of the particle.. (author)

2007-08-01

67

Effects of biopretreatment of corn stover with white-rot fungus on low-temperature pyrolysis products.  

Science.gov (United States)

The thermal decomposition of biopretreated corn stover during the low temperature has been studied by using the Py-GC/MS analysis and thermogravimetric analysis with the distributed activation energy model (DAEM). Results showed that biopretreatment with white-rot fungus Echinodontium taxodii 2538 can improve the low-temperature pyrolysis of biomass, by increasing the pyrolysis products of cellulose, hemicellulose (furfural and sucrose increased up to 4.68-fold and 2.94-fold respectively) and lignin (biophenyl and 3,7,11,15-tetramethyl-2-hexadecen-1-ol increased 2.45-fold and 4.22-fold, respectively). Calculated by DAEM method, it showed that biopretreatment can decrease the activation energy during the low temperature range, accelerate the reaction rate and start the thermal decomposition with lower temperature. ATR-FTIR results showed that the deconstruction of lignin and the decomposition of the main linkages between hemicellulose and lignin could contribute to the improvement of the pyrolysis at low temperature. PMID:21146404

Yang, Xuewei; Ma, Fuying; Yu, Hongbo; Zhang, Xiaoyu; Chen, Shulin

2011-02-01

68

Catalytic methods of deoxygenating water: Final report  

International Nuclear Information System (INIS)

As part of a programme on the optimization of pressurized water reactor (PWR) secondary side water treatment, methods of reducing the oxygen concentration from the feedwater without the use of toxic chemicals or chemicals that may produce undesirable by-products was sought for. Hydrogen was identified as such a chemical. Gamma radiation and catalysis were studied as means of promoting the reaction between oxygen and hydrogen, to form water with no byproducts. Two types of wet-proofed catalysts---the random bed and the ordered bed catalysts---were developed and tested under two modes of operation---liquid phase and gasliquid phase. Oxygen reduction down to concentrations of 1 ppB or less was achieved. Analytical models were developed for the processes from kinetic studies. Equations for use in designing deoxygenators for steam generator systems were derived. Computer simulations and experimental studies showed that gamma irradiation in the presence of hydrogen reduced oxygen to the low ppB levels at rates corresponding to G(/minus/O2) values in the range 1.5 to 2 molecules100 eV gamma energy absorbed. The gamma source strength required for reducing oxygen concentrations to acceptable levels was estimated. The location of the deoxygenator in a steam generator system is discussed. 41 refs., 21 figs., 11 tabs

1988-01-01

69

Low temperature synthesis of wurtzite zinc sulfide (ZnS) thin films by chemical spray pyrolysis.  

Science.gov (United States)

Zinc sulfide (ZnS) thin films have been synthesized by spray pyrolysis at 310 C using an aqueous solution of zinc chloride (ZnCl2) and thioacetamide (TAA). Highly crystalline films were obtained by applying TAA instead of thiourea (TU) as the sulfur source. X-ray diffraction (XRD) analyses show that the films prepared by TAA contained a wurtzite structure, which is usually a high temperature phase of ZnS. The crystallinity and morphology of the ZnS films appeared to have a strong dependence on the spray rate as well. The asymmetric polar structure of the TAA molecule is proposed to be the intrinsic reason of the formation of highly crystalline ZnS at comparatively low temperatures. The violet and green emissions from photoluminescence (PL) spectroscopy reflected the sulfur and zinc vacancies in the film. Accordingly, the photodetectors fabricated using these films exhibit excellent response to green and red photons of 525 nm and 650 nm respectively, though the band gaps of the materials, estimated from optical absorption spectroscopy, are in the range of 3.5-3.6 eV. PMID:23546181

Zeng, Xin; Pramana, Stevin S; Batabyal, Sudip K; Mhaisalkar, Subodh G; Chen, Xiaodong; Jinesh, K B

2013-05-14

70

Evaluation of Integrated Time-Temperature Effect in Pyrolysis Process of Historically Contaminated Soils with Cadmium (Cd) and Lead (Pb)  

Digital Repository Infrastructure Vision for European Research (DRIVER)

It is already known that heavy metals pollution causes important concern to human and ecosystem health. Heavy metals in soils at the European level represents 37.3% between main contaminates affecting soils (EEA, 2007). This paper illustrates results obtained in the framework of laboratory experiments concerning the evaluation of integrated time-temperature effect in pyrolysis process applied to contaminated soil by two different ways: it is about heavy metals historically contaminated soil f...

2013-01-01

71

Pyrolysis of coal  

Energy Technology Data Exchange (ETDEWEB)

When coal is heated in the absence of air, it is converted into a variety of solid, liquid and gaseous products. This process, referred to as pyrolysis, is one of the most important coal conversion processes. This paper starts with the presentation of experimental methods used for pyrolysis and is followed by a detailed discussion of the reaction parameters, including temperature, heating rate, particle size, gas flow, gas pressures, coal type and catalysis. Finally, kinetic models utilised in coal pyrolysis studies are discussed. The last section describes and compares different coal pyrolysis processes. 55 refs., 7 figs., 2 tabs.

Gonenc Sunol, Z.S.; Sunol, A.K. [Bogazici University, Istanbul (Turkey)

1994-12-31

72

Hydrogen-rich gas production from waste plastics by pyrolysis and low-temperature steam reforming over a ruthenium catalyst  

International Nuclear Information System (INIS)

Operating conditions for low-temperature pyrolysis and steam reforming of plastics over a ruthenium catalyst were investigated. In the range studied, the highest gas and lowest coke fractions for polystyrene (PS) with a 60 g h-1 scale, continuous-feed, two-stage gasifier were obtained with a pyrolyzer temperature of 673 K, steam reforming temperature of 903 K, and weight hourly space velocity (WHSV) of 0.10 g-sample g-catalyst-1 h-1. These operating conditions are consistent with optimum conditions reported previously for polypropylene. Our results indicate that at around 903 K, the activity of the ruthenium catalyst was high enough to minimize the difference between the rates of the steam reforming reactions of the pyrolysates from polystyrene and polypropylene. The proposed system thus has the flexibility to compensate for differences in chemical structures of municipal waste plastics. In addition, the steam reforming temperature was about 200 K lower than the temperature used in a conventional Ni-catalyzed process for the production of hydrogen. Low-temperature steam reforming allows for lower thermal input to the steam reformer, which results in an increase in thermal efficiency in the proposed process employing a Ru catalyst. Because low-temperature steam reforming can be also expected to reduce thermal degradation rates of the catalyst, the pyrolysis-steam reforming process with a Ru catalyst has the potential for use in small-scale production of hydrogen-rich gas from waste plastics that can be used for power generation.

2011-06-01

73

Coal hydromethanolysis with coke-oven gas: 1. Influence of temperature on the pyrolysis yields  

Energy Technology Data Exchange (ETDEWEB)

In order to improve the economy of the hydropyrolysis process by reducing the hydrogen cost, pyrolysis of coal has been carried out with a simulated coke-oven gas (55% H{sub 2}, 30% CH{sub 4}, 15% N{sub 2}) as the reactive gas at 3 MPa and between 700{degree}C and 900{degree}C. Comparisons have been made with hydropyrolysis, pyrolysis with helium and methanolysis under the same conditions. The results indicate that there are no major obstacles to the use of coke-oven gas as the reactive gas in coal pyrolysis. The experimental conditions have to be improved to optimize the yields of the valuable chemicals. 11 refs., 8 figs., 4 tabs.

Braekman-Danheux, C.; Cypres, R.; Fontana, A.; Laurent, P.; Hoegaerden, M. van (Universite Libre de Bruxelles, Bruxelles (Belgium). Service de Chimie Generale et Carbochimie)

1991-03-01

74

The influence of temperature on the yields of compounds existing in bio-oils obtained from biomass samples via pyrolysis  

Energy Technology Data Exchange (ETDEWEB)

The influence of temperature on the compounds existing in liquid products obtained from biomass samples via pyrolysis were examined in relation to the yield and composition of the product bio-oils. The product liquids were analysed by a gas chromatography mass spectrometry combined system. The bio-oils were composed of a range of cyclopentanone, methoxyphenol, acetic acid, methanol, acetone, furfural, phenol, formic acid, levoglucosan, guaiacol and their alkylated phenol derivatives. Thermal depolymerization and decomposition of biomass structural components, such as cellulose, hemicelluloses, lignin form liquids and gas products as well as a solid residue of charcoal. The structural components of the biomass samples mainly affect the pyrolytic degradation products. A reaction mechanism is proposed which describes a possible reaction route for the formation of the characteristic compounds found in the oils. The supercritical water extraction and liquefaction partial reactions also occur during the pyrolysis. Acetic acid is formed in the thermal decomposition of all three main components of biomass. In the pyrolysis reactions of biomass: water is formed by dehydration; acetic acid comes from the elimination of acetyl groups originally linked to the xylose unit; furfural is formed by dehydration of the xylose unit; formic acid proceeds from carboxylic groups of uronic acid; and methanol arises from methoxyl groups of uronic acid. (author)

Demirbas, Ayhan [Sila Science, Trabzon (Turkey)

2007-06-15

75

Wettability of poultry litter biochars at variable pyrolysis temperatures and their impact on soil wettability and water retention relationships  

Science.gov (United States)

To reduce the impact of poultry farming on greenhouse gas emissions, poultry farming waste - poultry litter - can be converted to biofuel and biochar through slow-pyrolysis, with the biochar added to agricultural soil for nutrient enrichment and carbon sequestration. While biochars from source materials other than poultry litter have been shown to sequester carbon and increase soil fertility, there is considerable variability in biochar behavior - even with biochars created from the same source material. This situation is exacerbated by our limited understanding of how biochars alter physical, chemical, and biological processes in agricultural soils. The focus of this work is to develop a mechanistic understanding of how poultry litter (PL) biochars affect the hydrology, microbial communities, N2O emissions, and nitrogen cycling in agricultural soils. The initial focus is on the impact of PL biochar on soil hydrology. PL from Perdue AgriRecycle, LLC (Seaford, Delaware) was used to produce biochars at pyrolysis temperatures from 300C to 600C. To explore the impact of these biochars on soil wettability, the PL biochars were mixed with a 30/40 Accusand in mass fractions from 0% to 100%. The water contact angle was then measured using a goniometer on these sand/biochar mixtures using the sessile drop method and a single layer of sample particles. The PL biochars produced at temperatures between 300C to 400C were hydrophobic, while those pyrolized at > 400C were hydrophilic. Water contact angles for samples with 100% biochar varied systematically with pyrolysis temperature, decreasing from 101.12 to 20.57 as the pyrolysis temperature increased from 300 to 600C. Even for small amounts of hydrophobic biochar added to the hydrophilic sand, the contact angle of the mixture was altered: for sand/biochar mixtures containing only 2% hydrophobic PL biochar by weight, the contact angle of the mixture increased from ~ 8 (0% biochar) to 20 (2% biochar). For higher mass fractions, the impact of hydrophobic PL biochar on the sand/mixture contact angle was more dramatic: for a sand/biochar mixture with 15% PL biochar, the contact angle was 40.12. Water drop penetration tests were also performed on these samples, and results were consistent with contact angles measured with the sessile drop method. To further explore the cause of the varying contact angle with pyrolysis temperature, the PL biochars were vigorously rinsed with deionized water or heated for 24 hours at 105C, and the contact angle measurements repeated. Both rinsing and heating samples rendered hydrophobic PL biochar hydrophilic. Rinsate samples were analyzed for total organic carbon and with GC-MS. These data suggest that bio-oils produced during slow-pyrolysis at temperatures hydrophobicity. These bio-oils could be removed through vigorous washing with deionized water or heating to 105C. The implication of these changes in water contact angle from PL biochar addition on water retention relationships for soil and on water distribution within pores will be discussed.

Yi, S. C.; Witt, B.; Guo, M.; Chiu, P.; Imhoff, P. T.

2012-12-01

76

Deoxygenation of Plant Fatty Acid using NiSnK/ SiO2 as Catalyst  

International Nuclear Information System (INIS)

Environmental friendly bio-oil which offers supply reliability as a potential alternative fuel, has spurred to rapid development of bio fuels technology. Palm oil is a potential renewable energy source for bio fuels production in the future and Malaysia is one of the world largest palm oil producers. However, undesired oxygen content in the plant fatty acid that contributes to low energy density, high viscosity, and low stability, makes the palm oil not effective to be used as bio fuels directly. In the present study, the performance of silica supported trimetal catalyst, NiSnK/ SiO2, on deoxygenation of used palm oil was evaluated. In addition, the effects of operating parameters, such as reaction temperature and weight hourly space velocity were investigated. Conversion of palmitic acid as high as 90 % was achieved in deoxygenation of used palm oil at reaction temperature 350 degree Celsius. In order to have a better understanding on the deoxygenation reaction, model compound system using the major saturated fatty acid in the used palm oil, palmitic acid was also carried out. Palmitic acid was found mainly decarboxylated into n-pentadecane with some decarboxylation and isomerization products. (author)

2013-01-01

77

Kinetics of biomass pyrolysis  

Energy Technology Data Exchange (ETDEWEB)

The project 'Kinetics of Biomass Pyrolysis' of the Laboratory of Energy and Process Engineering at Tampere University of Technology (TUT) studies pyrolysis reaction in pyrolysis oil (bio oil) production conditions and factors affecting the phenomenon. The project focuses especially on the effect of the internal heat transfer rate of wood fuel particles on pyrolysis-product yields. The work is linked to the project 'Integrated utilization chains of second-generation pyrolysis' of VTT Technical Research Centre of Finland. The pyrolysis phenomenon of a thermally thick woody fuel particle is modelled mathematically. The model will be validated with results from experiments in the laboratory at TUT as well as a literature study. The experiments in the laboratory will be done mainly with drop-tube reactors utilising measuring techniques developed for the reactors. In addition, a device is being designed and built to study wood and char heat transfer at variable temperature ranges. The specific heat of wood and char are studied by differential scanning calorimetry. The project started in 2008 for a period of three years. The main interest in 2008 was heat transfer studies of wood and its char. The focus in 2009 is on the specific heat capacity of wood, on the chemical kinetics of pyrolysis and on high-heating-rate pyrolysis experiments. A draft of the mathematical model is being written in 2009 and the model will be completed in 2010. (orig.)

Hankalin, V.; Raiko, R. (Tampere Univ. of Technology, Lab. of Energy and Process Engineering (Finland)), email: ville.hankalin@tut.fi

2009-10-15

78

Ocean (Deoxygenation Across the Last Deglaciation: Insights for the Future  

Directory of Open Access Journals (Sweden)

Full Text Available Anthropogenic warming is expected to drive oxygen out of the ocean as the water temperature rises and the rate of exchange between subsurface waters and the atmosphere slows due to enhanced upper ocean density stratification. Observations from recent decades are tantalizingly consistent with this prediction, though these changes remain subtle in the face of natural variability. Earth system model projections unanimously predict a long-term decrease in the global ocean oxygen inventory, but show regional discrepancies, particularly in the most oxygen-depleted waters, owing to the complex interplay between oxygen supply pathways and oxygen consumption. The geological record provides an orthogonal perspective, showing how the oceanic oxygen content varied in response to prior episodes of climate change. These past changes were much slower than the current, anthropogenic change, but can help to appraise sensitivities, and point toward potentially dominant mechanisms of change. Consistent with the model projections, marine sediments recorded an overall expansion of low-oxygen waters in the upper ocean as it warmed at the end of the last ice age. This expansion was not linearly related with temperature, though, but reached a deoxygenation extreme midway through the warming. Meanwhile, the deep ocean became better oxygenated, opposite the general expectation. These observations require that significant changes in apparent oxygen utilization occurred, suggesting that they will also be important in the future.

Samuel L. Jaccard

2014-03-01

79

De-oxygenation of CO2 by using Hydrogen, Carbon and Methane over Alumina-Supported Catalysts  

Directory of Open Access Journals (Sweden)

Full Text Available The de-oxygenation of CO2 was explored by using hydrogen, methane, carbon etc., over alumina supported catalysts. The alumina-supported ruthenium, rhodium, platinum, molybdenum, vanadium and magnesium catalysts were first reduced in hydrogen atmosphere and then used for the de-oxygenation of CO2. Furthermore, experimental variables for the de-oxygenation of CO2 were temperature (range 50 to 650 oC, H2/CO2 mole ratios (1.0 to 5, and catalyst loading (0.5 to 10 wt %. During the de-oxygenation of CO2 with H2 or CH4 or carbon, conversion of CO2, selectivity to CO and CH4 were estimated. Moreover, 25.4 % conversion of CO2 by hydrogen was observed over 1 wt% Pt/Al2O3 catalyst at 650 oC with 33.8 % selectivity to CH4. However, 8.1 to 13.9 % conversion of CO2 was observed over 1 wt% Pt/Al2O3 catalyst at 550 oC in the presence of both H2 and CH4. Moreover, 42.8 to 79.4 % CH4 was converted with 9 to 23.1 % selectivity to CO. It was observed that the de-oxygenation of CO2 by hydrogen, carbon and methane produced carbon, CO and CH4. 2012 BCREC UNDIP. All rights reservedReceived: 6th February 2012; Revised: 23rd April 2012; Accepted: 24th April 2012[How to Cite: R. Y. Raskar, K. B. Kale, A. G. Gaikwad. (2011. De-oxygenation of CO2 by using Hydrogen, Carbon and Methane over Alumina-Supported Catalysts. Bulletin of Chemical Reaction Engineering & Catalysis, 7 (1: 59-69. doi:10.9767/bcrec.7.1.1631.59-69][How to Link / DOI: http://dx.doi.org/10.9767/bcrec.7.1.1631.59-69 ] | View in

K.B. Kale

2012-06-01

80

A fundamental look at the low temperature pyrolysis of butylbenzene: Geological implications for the cracking of oil to gas  

Energy Technology Data Exchange (ETDEWEB)

The extrapolation of kinetics based on a detailed molecular kinetic mechanism may help to validate or correct the application of phenomenological laboratory kinetics to geological conditions of maturation. In this report, the cracking of already generated oil to lighter components was studied by examining the pyrolysis of a model compound, butylbenzene, from experimental and modeling perspectives. A chemical kinetic model was developed to include chemistries which occur at lower temperatures. At geological temperatures, the model predicted a pseudo-1st order rate constant quite consistent with the experimental rate constant obtained at higher temperature. Additional modeling and experiments were done in the presence of tetralin, a hydrogen donor, as it was clear that hydrogen played a critical role in the destruction of olefins and the intermediates formed from them.

Freund, H. [Exxon Research and Engineering Co., Annandale, NJ (United States)

1995-12-01

 
 
 
 
81

Pyrolysis and gasification of coal at high temperatures. Quarterly progress report No. 9, September 15, 1989--December 15, 1989  

Energy Technology Data Exchange (ETDEWEB)

Coals of different ranks will be pyrolyzed in a microscope hot-stage reactor using inert and reacting atmospheres. The macropore structure oft he produced chars will be characterized using video microscopy and digital image processing techniques to obtain pore size distributions. Comparative studies will quantify the effect of pyrolysis conditions (heating rates, final heat treatment temperatures, particle size and inert or reacting atmosphere) on the pore structure of the devolatilized chars. The devolatilized chars will be gasified in the regime of strong intraparticle diffusional limitations using O{sub 2}/N{sub 2} and O{sub 2}/H{sub 2}/N{sub 2} mixtures. Constant temperature and programmed-temperature experiments in a TGA will be used for these studies. Additional gasification experiments performed in the hot-stage reactor will be videotaped and selected images will be analyzed to obtain quantitative data on particle shrinkage and fragmentation.

Zygourakis, K.

1989-12-31

82

Modeling of biomass pyrolysis  

International Nuclear Information System (INIS)

The fuels used in industry and power sector for the last two decades have become expensive. As a result renewable energy source have been emerging increasingly important, of these, biomass appears to be the most applicable in the near future. The pyrolysis of biomass plays a key role amongst the three major and important process generally encountered in a gas producer, namely, pyrolysis, combustion and reduction of combustion products. Each biomass has its own pyrolysis characteristics and this important parameters must be known for the proper design and efficient operation of a gasification system. Thermogravimetric analysis has been widely used to study the devolatilization of solid fuels, such as biomass. It provides the weight loss history of a sample heated at a predetermined rate as a function of time and temperature. This paper presents the experimental results of modelling the weight loss curves of the main biomass components i.e. cellulose, hemicellulose and lignin. Thermogravimetric analysis of main components of biomass showed that pyrolysis is first order reaction. Furthermore pyrolysis of cellulose and hemicelluloe can be regarded as taking place in two stages, for while lignin pyrolysis is a single stage process. This paper also describes the Thermogravimetric Analysis (TGA) technique to predict the weight retained during pyrolysis at any temperature, for number of biomass species, such as cotton stalk, bagasse ad graoundnut shell. (author)

1995-04-01

83

Pyrolysis of Coal  

Directory of Open Access Journals (Sweden)

Full Text Available The paper presents a review of relevant literature on coal pyrolysis.Pyrolysis, as a process technology, has received considerable attention from many researchers because it is an important intermediate stage in coal conversion.Reactions parameters as the temperature, pressure, coal particle size, heating rate, soak time, type of reactor, etc. determine the total carbon conversion and the transport of volatiles and therebythe product distribution. Part of the possible environmental pollutants could be removed by optimising the pyrolysis conditions. Therefore, this process will be subsequently interesting for coal utilization in the future

Ra?enovi?, A.

2006-07-01

84

Chemical composition and temperature dependent performance of ZnO-thin film transistors deposited by pulsed and continuous spray pyrolysis  

Science.gov (United States)

Zinc oxide thin film transistors (TFTs) deposited by continuous and pulsed spray pyrolysis were investigated to analyze process kinetics which make reduction of process temperature possible. Thus, fluid mechanics, chemical composition, electrical performance, and deposition and annealing temperature were systematically analyzed. It was found that ZnO layers continuously deposited at 360 C contained zinc oxynitrides, CO3, and hydro carbonate groups from pyrolysis of basic zinc acetate. Statistically, every second wurtzite ZnO unit cell contained an impurity atom. The purity and performance of the ZnO-TFTs increased systematically with increasing deposition temperature due to an improved oxidation processes. At 500 C the zinc to oxygen ratio exceeded a high value of 0.96. Additionally, the ZnO film was not found to be in a stabilized state after deposition even at high temperatures. Introducing additional subsequent annealing steps stabilizes the film and allows the reduction of the overall thermal stress to the substrate. Further improvement of device characteristics was obtained by pulsed deposition which allowed a more effective transport of the by-products and oxygen. A significant reduction of the deposition temperature by 140 C was achieved compared to the same performance as in continuous deposition mode. The trap density close to the Fermi energy could be reduced by a factor of two to 4 1017 eV-1 cm-3 due to the optimized combustion process on the surface. The optimization of the deposition processes made the fabrication of TFTs with excellent performance possible. The mobility was high and exceeded 12 cm2/V s, the subthreshold slope was 0.3 V dec-1, and an on-set close to the ideal value of 0 V was achieved.

Ortel, Marlis; Balster, Torsten; Wagner, Veit

2013-12-01

85

In-plane aligned YBCO thick films grown in situ by high temperature ultrasonic spray pyrolysis  

International Nuclear Information System (INIS)

Ultrasonic spray pyrolysis (USP) has been used to deposit thick films (up to 5 micron) of YBa2Cu3O7-x in situ on single-crystal oxide substrates, and single-crystal and textured polycrystalline Ag foil of different orientations. Epitaxial films grow with a strong level of in-plane texture on the single crystal oxide substrates (c of 91 K with transition widths of ? 6 K. The films are fully connected and Jc are ? 1.0x104 A cm-2 at 77 K and ? 5x105 A cm-2 at 20 K. (author)

2001-02-01

86

Leidenfrost temperature related CVD-like growth mechanism in ZnO-TFTs deposited by pulsed spray pyrolysis  

Science.gov (United States)

Zinc oxide thin films were prepared by pulsed spray pyrolysis (SP) from aqueous zinc acetate precursor solution. The deposition behavior of the solution with regard to the pool boiling curve of the solvent was investigated to gain insights of the deposition mechanism which leads to homogeneous and reproducible ZnO layers. The Leidenfrost effect was found to play an important role since the Leidenfrost temperature has to be exceeded to form high quality layers. It is concluded that 3D nucleation of ZnO nano-crystals takes place out of the gaseous phase by a CVD-like process on ITO as well as on SiO2 substrates. Crystal orientation and surface roughness of the zinc oxide layer are found to depend strongly on the substrate. An increasing grain size with film thickness is observed. These findings were utilized to fabricate and investigate the semiconducting properties of the films in ZnO thin film transistors (TFTs). The mobility exceeded 12 cm2 V-1 s-1, the on-set was at 1 V and the on-off current ratio was found to be higher than 108. Hence the morphology and the electrical parameters of the ZnO films deposited by pulsed spray pyrolysis from non-toxic aqueous zinc acetate solution above the Leidenfrost point show excellent properties for electronic applications.

Ortel, Marlis; Wagner, Veit

2013-01-01

87

On the structure of tungsten and molybdenum films deposited from gas phase during low-temperature pyrolysis of carbonyls  

International Nuclear Information System (INIS)

X-ray diffraction and electron diffraction analyses were used to study the structure of fine films of refractory metals (W and Mo) precipitated from the gas phase as a result of pyrolysis of corresponding carbonyl vapours at 300-400 deg C. Low-temperature pyrolysis was shown to lead to formation of a metastable face-centred cubic phase, i.e. of an interstitial solid solution with variable composition. Experimental studies involving subsequent heat treatment were performed to determine structural transformations in the films. Annealing 600-800 deg C resulted in disintegration of the face-centred cubic phase and, in the case of W, in the appearance of a volumetrically centred cubic lattice (?=3.16 A) characteristic of a pure metal; in the case of Mo, annealing led to formation of a hexagonal molybdenum carbide, Mo2C. The different behaviour of Mo and W films during heat treatment was due to the different amounts of carbon contained in the initial films (4.2-4.7 wt.% and 0.7-0.9 wt.% for Mo and W, respectively, according to vacuum-chromatographic analysis data)

1977-01-01

88

Study of surface cleaning methods and pyrolysis temperatures on nanostructured carbon films using x-ray photoelectron spectroscopy  

Energy Technology Data Exchange (ETDEWEB)

Nanostructured carbon (ns-C) films fabricated by stabilization and pyrolysis of diblock copolymers are of interest for a variety of electrical/electronic applications due to their chemical inertness, high-temperature insensitivity, very high surface area, and tunable electrical resistivity over a wide range [Kulkarni et al., Synth. Met. 159, 177 (2009)]. Because of their high porosity and associated high specific surface area, controlled surface cleaning studies are important for fabricating electronic devices from these films. In this study, quantification of surface composition and surface cleaning studies on ns-C films synthesized by carbonization of diblock copolymers of polyacrylonitrile-b-poly(n-butyl acrylate) at two different temperatures were carried out. X-ray photoelectron spectroscopy was used for elemental analysis and to determine the efficacy of various surface cleaning methods for ns-C films and to examine the polymer residues in the films. The in-situ surface cleaning methods included HF vapor treatment, vacuum annealing, and exposure to UV-ozone. Quantitative analysis of high-resolution XPS scans showed 11 at. % nitrogen was present in the films pyrolyzed at 600 Degree-Sign C, suggesting incomplete denitrogenation of the copolymer films. The nitrogen atomic concentration decreased significantly for films pyrolyzed at 900 Degree-Sign C confirming extensive denitrogenation at that temperature. Furthermore, quantitative analysis of nitrogen subpeaks indicated higher loss of nitrogen atoms residing at the edge of graphitic clusters relative to that of nitrogen atoms within the graphitic clusters, suggesting higher graphitization with increasing pyrolysis temperature. Of the surface cleaning methods investigated, in-situ annealing of the films at 300 Degree-Sign C for 40 min was found to be the most efficacious in removing adventitious carbon and oxygen impurities from the surface.

Kerber, Pranita; Porter, Lisa M.; McCullough, Lynne A.; Kowalewski, Tomasz; Engelhard, Mark; Baer, Donald [Department of Materials Science and Engineering, Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, Pennsylvania 15213 (United States); Chemistry Department, Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, Pennsylvania 15213 (United States); Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, Washington 99352 (United States)

2012-11-15

89

Study of surface cleaning methods and pyrolysis temperatures on nanostructured carbon films using x-ray photoelectron spectroscopy  

International Nuclear Information System (INIS)

Nanostructured carbon (ns-C) films fabricated by stabilization and pyrolysis of diblock copolymers are of interest for a variety of electrical/electronic applications due to their chemical inertness, high-temperature insensitivity, very high surface area, and tunable electrical resistivity over a wide range [Kulkarni et al., Synth. Met. 159, 177 (2009)]. Because of their high porosity and associated high specific surface area, controlled surface cleaning studies are important for fabricating electronic devices from these films. In this study, quantification of surface composition and surface cleaning studies on ns-C films synthesized by carbonization of diblock copolymers of polyacrylonitrile-b-poly(n-butyl acrylate) at two different temperatures were carried out. X-ray photoelectron spectroscopy was used for elemental analysis and to determine the efficacy of various surface cleaning methods for ns-C films and to examine the polymer residues in the films. The in-situ surface cleaning methods included HF vapor treatment, vacuum annealing, and exposure to UV-ozone. Quantitative analysis of high-resolution XPS scans showed 11 at. % nitrogen was present in the films pyrolyzed at 600 C, suggesting incomplete denitrogenation of the copolymer films. The nitrogen atomic concentration decreased significantly for films pyrolyzed at 900 C confirming extensive denitrogenation at that temperature. Furthermore, quantitative analysis of nitrogen subpeaks indicated higher loss of nitrogen atoms residing at the edge of graphitic clusters relative to that of nitrogen atoms within the graphitic clusters, suggesting higher graphitization with increasing pyrolysis temperature. Of the surface cleaning methods investigated, in-situ annealing of the films at 300 C for 40 min was found to be the most efficacious in removing adventitious carbon and oxygen impurities from the surface.

2012-11-01

90

Influence of pyrolysis temperature and heating rate on the production of bio-oil and char from safflower seed by pyrolysis, using a well-swept fixed-bed reactor  

Energy Technology Data Exchange (ETDEWEB)

In this study, fast pyrolysis of safflower seed (Carthamus tinctorius L.) was investigated with the aim to study the product distribution and their chemical compositions and to identify optimum process conditions for maximizing the bio-oil yield. Experiments were performed in a well-swept resistively heated fixed-bed reactor under nitrogen atmosphere. The maximum oil yield of 54% was obtained at the final pyrolysis temperature of 600 C, sweeping gas flow rate of 100 cm{sup 3} min{sup -} {sup 1} and heating rate of 300 C min{sup -} {sup 1} in a fixed-bed reactor. The elemental analysis and calorific value of the bio-oil were determined and compared with diesel fuel and then the chemical composition of the bio-oil was investigated using chromatographic and spectroscopic techniques (IR, GC/MS, simulated distillation). The char was characterized by elemental, BET surface area and SEM analyses. (author)

Onay, Ozlem [Porsuk Vocational School, Anadolu University, 26470 Eskisehir (Turkey)

2007-05-15

91

Coal pyrolysis: Literature survey  

Energy Technology Data Exchange (ETDEWEB)

This literature survey has been conducted to form a firm historical basis for continuing research in the field of coal pyrolysis. The literature contains extensive reference to the pyrolysis of coal. This search is not intended to be comprehensive. The emphasis has been placed on elucidating past methods of manipulating the following seven most important variables for coal pyrolysis: (1) time, (2) temperature, (3) pressure, (4) atmosphere, (5) coal rank and type, (6) heating rate, and (7) coal pretreatment and handling. Each of these variables will act as a subsection of the following review. Various methodologies for studying the process of pyrolyzing coal are briefly outlined. Some consideration is given to studies that are concerned mainly with the chemical makeup of coal and how it relates to the chemical makeup of the pyrolysis product. Emphasis has been placed on the most recent literature when the topic has been well covered in previous reviews. 147 refs.

Brandes, S.D.

1988-03-01

92

Room-temperature ferromagnetism in Sn1-xMnxO2 nanocrystalline thin films prepared by ultrasonic spray pyrolysis  

International Nuclear Information System (INIS)

Sn1-xMnxO2 (x=0.01-0.05) thin films were synthesized on quartz substrate using an inexpensive ultrasonic spray pyrolysis technique. The influence of doping concentration and substrate temperature on structural and magnetic properties of Sn1-xMnxO2 thin films was systematically investigated. X-ray diffraction (XRD) studies of these films reflect that the Mn3+ ions have substituted Sn4+ ions without changing the tetragonal rutile structure of pure SnO2. A linear increase in c-axis lattice constant has been observed with corresponding increase in Mn concentration. No impurity phase was detected in XRD patterns even after doping 5 at% of Mn. A systematic change in magnetic behavior from ferromagnetic to paramagnetic was observed with increase in substrate temperature from 500 to 700 deg. C for Sn1-xMnxO2 (x=0.01) films. Magnetic studies reveal room-temperature ferromagnetism (RTFM) with 3.61x10-4 emu saturation magnetization and 92 Oe coercivity in case of Sn1-xMnxO2 (x=0.01) films deposited at 500 deg. C. However, paramagnetic behavior was observed for the films deposited at a higher substrate temperature of 700 deg. C. The presence of room-temperature ferromagnetism in these films was observed to have an intrinsic origin and could be obtained by controlling the substrate temperature and Mn doping concentration.

2009-11-01

93

Low temperature polycrystalline silicon film formation by metal induced crystallization with nickel salt derived by ultrasonic spray pyrolysis  

Energy Technology Data Exchange (ETDEWEB)

Solution-based nickel induced crystallization of amorphous silicon (a-Si) films was performed. The nickel solution was prepared by dissolving (CH{sub 3}CO{sub 2}){sub 2}Ni in deionized water and applied uniformly on a-Si films by low-cost ultrasonic spray pyrolysis method. Crystallization could be realized for a-Si films coated with a 0.2 M nickel solution and annealed at 500 C. The effect of substrate temperature during nickel solution deposition was analyzed. Micro-Raman and x-ray diffraction measurement show that a-Si is fully crystallized at 550 C for 7 h with a nickel concentration of 0.8 M. (copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

Yang, Mingfei; Sun, Xiao Wei; Yu, Hong Yu.; Li, Junshuai; Hu, Junhui [School of Electrical and Electronic Engineering, Nanyang Technological University, Singapore 639798 (Singapore)

2011-09-15

94

Catalytic pyrolysis of waste rice husk over mesoporous materials  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Catalytic fast pyrolysis of waste rice husk was carried out using pyrolysis-gas chromatography/mass spectrometry [Py-GC/MS]. Meso-MFI zeolite [Meso-MFI] was used as the catalyst. In addition, a 0.5-wt.% platinum [Pt] was ion-exchanged into Meso-MFI to examine the effect of Pt addition. Using a catalytic upgrading method, the activities of the catalysts were evaluated in terms of product composition and deoxygenation. The structure and acid site characteristics of the catalysts were analyzed b...

Jeon, Mi-jin; Kim, Seung-soo; Jeon, Jong-ki; Park, Sung Hoon; Kim, Ji Man; Sohn, Jung Min; Lee, See-hoon; Park, Young-kwon

2012-01-01

95

Stable carbon isotope compositions of gaseous hydrocarbons produced from high pressure and high temperature pyrolysis of lignite  

Energy Technology Data Exchange (ETDEWEB)

Pyrolysis of lignite at high pressure and high temperature (HPT) was conducted to investigate the potential stable carbon isotopic fractionation of the produced gaseous hydrocarbons. The experiments were done in a closed system at temperatures of 500-700{sup o}C and pressures of 1-3 gigapascals (GPa). Gas chromatography-combustion-isotope ratio mass spectrometric analysis of the produced gaseous hydrocarbons leads to two important observations. First, the distribution of the {delta}-{sup 13}C values for methane, ethane, propane and butane shows a clear reversal, with {delta}-{sup 13}C{sub 1} {gt} {delta}-{sup 13}C{sub 2} {gt} {delta}-{sup 13}C{sub 3} {gt} {delta}-{sup 13}C{sub 4}. The relatively {sup 13}C -enriched methane and {sup 13}C-depleted butane is in contrast to the widely accepted isotope distribution pattern of biogenic gases and is similar to that reported for abiogenic gases. Second, carbon dioxide produced from the pyrolysis of lignite is relatively enriched in {sup 13}C, with {delta}-{sup 13}C values (-18.6 to -22.3 parts per thousand) that are much higher than those of the gaseous hydrocarbons and lignite itself (-26.8 parts per thousand). These findings suggest a possible scenario that gaseous hydrocarbons can be generated from organic matter under the HPT conditions of the lower lithosphere, particularly in subduction regions where sedimentary organic matter might be introduced into the mantle, and that the reversal in the stable carbon isotopes of gaseous hydrocarbons may not be an exclusive indicator of abiogenic gases. Therefore, isotope criteria commonly used to differentiate biogenic from abiogenic gases should be used with caution.

Du, J.G.; Jin, Z.J.; Xie, H.S.; Bai, L.P.; Liu, W. [Chinese Academy of Science, Guiyang (China)

2003-07-01

96

Formation of liquid and solid products from liquid phase pyrolysis.  

Science.gov (United States)

The aim of the present work was to improve the C:O ratio in biomass by preserving the lignin macrostructure of lignocellulosic feed. The intention of liquid phase pyrolysis is to liquefy biomass and prepare biomass for further upgrading steps like hydrogenation and deoxygenation. Pyrolysis was carried out in a non-aqueous liquid phase heat carrier. The process was carried out in a semi-batch reaction vessel under isothermal conditions at T=350C, supported by a quench to stop reactions instantaneously in order to observe formation of solid intermediates. This pyrolysis system enables the observation of liquid and solid product formation. Transformation of biomass into biochar was analyzed by infrared spectroscopy and elemental analysis. Stable lignin structure throughout the whole transformation was confirmed. It was shown that the lignin frame in wood remains without substantial loss, while the major amount of carbohydrates is pyrolyzed during liquid phase pyrolysis at T=350C. PMID:22989638

Schwaiger, N; Witek, V; Feiner, R; Pucher, H; Zahel, K; Pieber, A; Pucher, P; Ahn, E; Chernev, B; Schroettner, H; Wilhelm, P; Siebenhofer, M

2012-11-01

97

Temperature dependence of the photoluminescence spectra of CdS: In thin films prepared by the spray pyrolysis technique  

International Nuclear Information System (INIS)

Indium doped cadmium sulfide thin films (CdS:In) are prepared by the spray pyrolysis technique on glass substrates using a home-made spraying system at a substrate temperature Ts=490 C. The photoluminescence (PL) spectra are recorded at different temperatures in the range 24160 K. Two broad peaks were observed; a strong one in the visible region centered on E?2.0 eV and a weak one in the infrared region centered on E?1.06 eV. The first one is deconvoluted into two Gaussian peaks corresponding to the yellow and red bands, and the second one is deconvoluted into one Gaussian peak corresponding to the infrared band. A strong quenching of the PL intensity with temperature is observed after T=60 K for the yellow and infrared bands and after T=90 K for the red band. The activation energy Ea was estimated by using the Arrhenius plot for the different bands. The estimated values for the three bands lie in the range Ea?23.427.3 meV. The peak positions of the yellow and red bands are red-shifted after T=90 K, while the peak position of the infrared band is blue shifted in the whole temperature range. The full width at half maximum (FWHM) for the three bands increases with temperature. According to these findings the three bands are explained in terms of bound excitons. -- Highlights: The photoluminescence (PL) of sprayed CdS:In thin films is recorded at different temperatures. The PL spectrum is deconvoluted to three Gaussian peaks corresponding to yellow, red and infrared bands. The decrease of the PL intensity with temperature for these bands has similar behaviors. The yellow and red bands are red-shifted with temperature, but the infrared band is blue-shifted. From the Arrhenius plots the activation energy is estimated

2013-10-01

98

The Effect of Substrate Temperature on Superconducting Properties of YBCO Films Prepared by Spray Pyrolysis Method using Metal Nitrate Precursors  

International Nuclear Information System (INIS)

YBCO films have been synthesized using a spray pyrolysis method. We used nitrates of Y, Ba, Cu as precursors. Deposition was made on LaAlO3 (100) single crystal substrate by spraying the mist of aqueous precursor solution generated by a concentric nozzle. The distance between concentric nozzle and substrate was 15 cm. C-axis oriented films were obtained at deposition temperature of 740 - 800 degrees C and working pressure of 20 Torr. Oxygen partial pressure was 3 Torr and substrate was transported with the speed ranging from 0.23 cm/min to 0.7 cm/min by reel to reel. Scanning electron microscope (SEM) and X-ray diffraction (XRD) observation revealed that films are smooth and highly textured with (001) planes parallel to substrate. Highest critical current density (Jc) was 1.38 MA/cm2 at 77K and self-field for the film with a thickness of 0.5 ?m prepared at a substrate temperature of 780 degrees C and PO2 = 3 Torr . The effect of temperature on the microstructure and YBCO phase formation will be discussed.

2007-10-01

99

Catalytic pyrolysis of Laminaria japonica over nanoporous catalysts using Py-GC/MS  

Science.gov (United States)

The catalytic pyrolysis of Laminaria japonica was carried out over a hierarchical meso-MFI zeolite (Meso-MFI) and nanoporous Al-MCM-48 using pyrolysis gas chromatography/mass spectrometry (Py-GC/MS). The effect of the catalyst type on the product distribution and chemical composition of the bio-oil was examined using Py-GC/MS. The Meso-MFI exhibited a higher activity in deoxygenation and aromatization during the catalytic pyrolysis of L. japonica. Meanwhile, the catalytic activity of Al-MCM-48 was lower than that of Meso-MFI due to its weak acidity.

Lee, Hyung Won; Jeon, Jong-Ki; Park, Sung Hoon; Jeong, Kwang-Eun; Chae, Ho-Jeong; Park, Young-Kwon

2011-08-01

100

Catalytic pyrolysis of Laminaria japonica over nanoporous catalysts using Py-GC/MS  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The catalytic pyrolysis of Laminaria japonica was carried out over a hierarchical meso-MFI zeolite (Meso-MFI) and nanoporous Al-MCM-48 using pyrolysis gas chromatography/mass spectrometry (Py-GC/MS). The effect of the catalyst type on the product distribution and chemical composition of the bio-oil was examined using Py-GC/MS. The Meso-MFI exhibited a higher activity in deoxygenation and aromatization during the catalytic pyrolysis of L. japonica. Meanwhile, the catalytic activity of Al-MCM-4...

Lee, Hyung Won; Jeon, Jong-ki; Park, Sung Hoon; Jeong, Kwang-eun; Chae, Ho-jeong; Park, Young-kwon

2011-01-01

 
 
 
 
101

Use of low-temperature nanostructured CuO thin films deposited by spray-pyrolysis in lithium cells  

Energy Technology Data Exchange (ETDEWEB)

Nanostructured CuO thin films were prepared by spray pyrolysis of aqueous copper acetate solutions at temperatures over 200-300 deg C range. The textural and structural properties of the films were determined by scanning electron microscopy, atomic force microscopy, X-ray diffraction spectroscopy and X-ray photoelectron spectroscopy (XPS). Although the sole crystalline phase detected in the film was CuO, XPS spectra revealed a more complex surface structure due to the presence of undecomposed copper acetate that can be easily removed by Ar{sup +} ion sputtering. The heating temperature was found to have little limited effect on the particle size and thickness of the films, which, however, increased significantly increasing deposition time. The film with the smallest grain size exhibited an excellent electrochemical response in Li battery electrodes and was capable of supplying sustained specific capacity as high as 625 A h kg{sup -1} (50% greater than that delivered by bulk CuO and close to the theoretical capacity for the CuO<=>Cu reaction) upon extensive cycling.

Morales, J. [Departamento de Quimica Inorganica e Ingenieria Quimica, Facultad de Ciencias, Campus de Rabanales, Edificio Marie Curie, Universidad de Cordoba, 14071 Cordoba (Spain); Sanchez, L. [Departamento de Quimica Inorganica e Ingenieria Quimica, Facultad de Ciencias, Campus de Rabanales, Edificio Marie Curie, Universidad de Cordoba, 14071 Cordoba (Spain)]. E-mail: luis-sanchez@uco.es; Martin, F. [Laboratorio de Materiales y Superficie (Unidad Asociada al CSIC), Universidad de Malaga (Spain); Ramos-Barrado, J.R. [Laboratorio de Materiales y Superficie (Unidad Asociada al CSIC), Universidad de Malaga (Spain); Sanchez, M. [Laboratorio de Materiales y Superficie (Unidad Asociada al CSIC), Universidad de Malaga (Spain)

2005-03-01

102

Neurovascular coupling in rat brain operates independent of hemoglobin deoxygenation  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Recently, a universal, simple, and fail-safe mechanism has been proposed by which cerebral blood flow (CBF) might be coupled to oxygen metabolism during neuronal activation without the need for any tissue-based mechanism. According to this concept, vasodilation occurs by local erythrocytic release of nitric oxide or ATP wherever and whenever hemoglobin is deoxygenated, directly matching oxygen demand and supply in every tissue. For neurovascular coupling in the brain, we present experimental ...

2010-01-01

103

Effects of working temperature and carbon diffusion on the microstructure of high pressure heat-resistant stainless steel tubes used in pyrolysis furnaces during service condition  

International Nuclear Information System (INIS)

Highlights: ? Microstructure of HP tubes used in pyrolysis furnaces during service condition was studied. ? Two major phases, namely chromium and niobium carbides, existed in HP tubes in as-cast conditions. ? Temperature and carbon diffusion influence the composition and volume fraction of secondary precipitates. ? Chromium and niobium carbides were transformed to M23C6 and G-phase respectively during service. -- Abstract: In the present study, high pressure heat-resistant cast stainless steels (HP steels) modified with niobium and titanium were investigated in as-cast conditions and after being used in pyrolysis furnaces. Life span of the studied specimens obtained from pyrolysis furnace was 5 years. Microstructural changes were studied via scanning electron microscopy (SEM) equipped with energy dispersive spectrum (EDS), optical microscopy (OM), and X-ray diffraction (XRD). The effect of temperature and carbon diffusion on the microstructure, chromium-rich carbides, the NbC transformation to G-phase and other precipitates formed during service condition were discussed. The results showed that two major phases, namely chromium and niobium carbides, existed in the as-cast specimens. Temperature and carbon diffusion influenced the composition and volume fraction of secondary precipitates. Chromium and niobium carbides were transformed to M23C6 and G-phase respectively during service. Higher working temperatures do not always cause coarsening of precipitates. However, factors such as decarburization and carbon diffusion have important roles, too.

2012-02-01

104

Neurovascular coupling in rat brain operates independent of hemoglobin deoxygenation.  

Science.gov (United States)

Recently, a universal, simple, and fail-safe mechanism has been proposed by which cerebral blood flow (CBF) might be coupled to oxygen metabolism during neuronal activation without the need for any tissue-based mechanism. According to this concept, vasodilation occurs by local erythrocytic release of nitric oxide or ATP wherever and whenever hemoglobin is deoxygenated, directly matching oxygen demand and supply in every tissue. For neurovascular coupling in the brain, we present experimental evidence challenging this view by applying an experimental regime operating without deoxy-hemoglobin. Hyperbaric hyperoxygenation (HBO) allowed us to prevent hemoglobin deoxygenation, as the oxygen that was physically dissolved in the tissue was sufficient to support oxidative metabolism. Regional CBF and regional cerebral blood oxygenation were measured using a cranial window preparation in anesthetized rats. Hemodynamic and neuronal responses to electrical forepaw stimulation or cortical spreading depression (CSD) were analyzed under normobaric normoxia and during HBO up to 4 ATA (standard atmospheres absolute). Inconsistent with the proposed mechanism, during HBO, CBF responses to functional activation or CSD were unchanged. Our results show that activation-induced CBF regulation in the brain does not operate through the release of vasoactive mediators on hemoglobin deoxygenation or through a tissue-based oxygen-sensing mechanism. PMID:20040927

Lindauer, Ute; Leithner, Christoph; Kaasch, Heike; Rohrer, Benjamin; Foddis, Marco; Fchtemeier, Martina; Offenhauser, Nikolas; Steinbrink, Jens; Royl, Georg; Kohl-Bareis, Matthias; Dirnagl, Ulrich

2010-04-01

105

Effect of pyrolysis temperature of carbon-supported metal-free and cobalt dibenzotetraazaannulene on the electrochemical characteristics of air electrodes in acidic and alkaline electrolytes  

Energy Technology Data Exchange (ETDEWEB)

It was of interest to study the effect of metal-free (H/sub 2/DTAA) and cobalt (CoDTAA) dibenzotetraazaannulene pyrolysis temperature on the electrochemical characteristics of carbon-air (oxygen) electrodes in alkaline electrolyte, and compare the results obtained with similar results for electrodes in acidic electrolyte. The authors studied two-layer electrodes of carbon black wetproofed with polytetrafluoroethylene and carbon catalysts with a working surface area of 10 cm/sup 2/. The values of electrode potential as functions of the logarithm of current density in oxygen were determined. Electrochemical measurements included recording steady-state polarization curves for the electrodes in air and in oxygen at room temperature. It is shown that the enhanced activity of the catalysts studied is caused by pyrolysis products of the organic macrocycle, both in 7 N KOH and in 4.5 N H/sub 2/SO/sub 4/.

Gamburtsev, S.; Grunig, G.; Iliev, I.; Kaisheva, A.; Wiesener, K.

1986-08-01

106

Application of biochar from sewage sludge to plant cultivation: Influence of pyrolysis temperature and biochar-to-soil ratio on yield and heavy metal accumulation.  

Science.gov (United States)

Applying biochar products from sewage sludge (SS) pyrolysis as soil amendment for plant cultivation was investigated in this study with special attention paid to heavy metal accumulation in the plants when pyrolysis temperature and biochar-to-soil mass ratio (C:S) were changed. Biochar obtained at four different temperatures were adopted as soil amendment for Allium sativum L. garlic plant cultivation. Experimental results revealed that biochars were rich in nutrient contents and they improved garlic yields. Although contents of heavy metals including As, Zn, Pb, Ni, Cd, Cr and Cu, etc. were elevated in the biochars compared to local soil, they fell within the acceptable limits for land application and SS is a suitable biochar resource, especially biochar produced at 450C had rich micropores, relatively stable functional groups in structure and rugged surface to contact well with soil, conducive to its usage as a biochar. The garlic grew faster when planted in the biochar-amended soil and had higher final dry matter yields than those planted in the reference soil, especially biochar produced at 450C corresponding to the highest final yields. The C:S ratio related to the highest garlic yields changed when the pyrolysis temperature was changed and this ratio was 1:4 for the biochar produced at 450C. General heavy metal accumulation in the garlic occurred only for the most enriched Zn and Cu, and mainly in the roots & bulbs; in addition this bioaccumulation was increasing as leaching from biochar increased but not increasing with C:S ratio. The garlic planted in soil amended with biochar of 450C contained the lowest level of heavy metals compared to other biochars. Those results indicated that heavy metal accumulation in plants can be inhibited through proper pyrolysis temperature choice and prevention of heavy metal leaching from the SS biochar. PMID:24582602

Song, X D; Xue, X Y; Chen, D Z; He, P J; Dai, X H

2014-08-01

107

Do molecular assemblages released at progressive pyrolysis temperatures reflect different organizational levels in the structure of soil humic acid?  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Analytical pyrolysis is a classical tool for the structural research of humic substances, invoked as a technique superior to wet chemical degradation because its outstanding potential for the breakdown of the CC bonds even in the most recalcitrant structural domains. Also, it enables the release of a large variety of products in a wide range of polarity and derived from lipid, carbohydrate, lignin or protein. Nevertheless, the potential of analytical pyrolysis for unbiased structural analys...

Almendros, G.; Herna?ndez, Zulimar; Gonza?lez-pe?rez, Jose? Antonio; Cuadra, L.; Ferna?ndez, E.

2008-01-01

108

Improved superconducting properties of MgB2 thin films fabricated by ultrasonic spray pyrolysis method at high temperature  

Science.gov (United States)

High quality MgB2 superconducting thin films have been successfully prepared by 2.4 MHz ultrasonic spray pyrolysis (USP) system on single crystal Al2O3 (0 0 1) substrates. The microstructure, electrical and magnetic properties of approximately 500-600 nm thick films were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM) in conjunction with the energy dispersive X-ray analysis (EDX), resistance versus temperature (R-T) and magnetization measurements (M-H) under different magnetic fields and transport critical current density (Jc). Films were first heat treated in situ in the spraying chamber with an extra Mg powder during deposition to compensate excess evaporation of Mg from the films and then additionally heat treated in Ar atmosphere at 700 C for a short time. According to the results obtained, orientation on any particular direction for the crystal growth was not seen. Homogeneous, highly dense and highly smooth surface morphology and low resistance have been achieved under optimum conditions. Optimally treated films exhibited relatively high transport critical current density of 2.37 105 A cm-2. These results have been also compared with the Jcmag results calculated from the M-H curves. The electrical resistance property of the best samples was obtained to be 39.5 and 37.4 K for Tc and Tzero, respectively.

Yakinci, M. Eyyuphan; Yakinci, Z. Deniz; Aksan, M. Ali; Balci, Yakup

2012-12-01

109

Low temperature growth of highly crystallized ZnO:Al films by ultrasonic spray pyrolysis from acetylacetone salt  

International Nuclear Information System (INIS)

High-quality ZnO:Al films were deposited on glass substrates at a relatively low temperature of 300 deg. C by ultrasonic spray pyrolysis. Zn(acac)2 and Al(acac)3 acted as zinc and aluminum source, which dissolved in ethanol-water solution. The influences of aluminum concentration and vacuum annealing on microstructure, electrical and optical properties were investigated by XRD, SEM, EDS, four-point probe and visible spectroscopy. The experimental results shown that ZnO:Al films exhibit stronger (1 0 1) preferred orientation and have lenticular-like grain morphology. The resistivity as low as 4.3 x 10-1 ? cm for as-deposited films was obtained at the 4 at.% doping concentration, which can be decreased to 10-2 ? cm level by post-deposited vacuum annealing. The average transmittance of as-deposited films was nearly 80% in the visible range, and that of 4 at.% doped ZnO films reduced to 60% after vacuum annealing at 550-600 deg. C.

2010-03-25

110

PYROLYSIS OF WOODY MATERIAL  

Directory of Open Access Journals (Sweden)

Full Text Available This work aimed to study the recovery of beech wood by the process of pyrolysis. The effects ofexperimental conditions in products yield and composition were studied. The thermal behaviour offorestry biomass was studied in a batch reactor at temperatures ranging from 350oC to 450oC. Thereaction time of wood thermal degradation took 95 min. The main objective was the identificationof the oxygenates and carbonaceous species generated by pyrolysis of beech wood. The productsof wood cracking were classified into three groups : 25.1 %wt. of gas, 44.3 %wt. of liquids and30.6 %wt. of carbon solid residues. There is considerable experimental evidence that suggests thatthere is competition between gas, liquids and char during wood pyrolysis which depends on theheating conditions.

Martin Bajus

2010-09-01

111

Modelling of black liquor pyrolysis  

Energy Technology Data Exchange (ETDEWEB)

The paper describes a mathematical model for pyrolysis of black liquor droplets in high temperature atmosphere. Black liquor as a fuel has similarities to different liquid fuels as heavy fuel oil droplet, multicomponent liquid fuel and coal water slurry. Models for heavy fuel oil, coal water slurry and multicomponent liquid fuel vaporization and pyrolysis have been presented. The black liquor droplets contain a great amount of water and the drying and pyrolysis occurs partly simultaneously according to calculations based on the present model even when the droplet size is small. The black liquor droplets swell significantly during drying and pyrolysis. The droplet volume increases to a size about 30 times the original size. The model presented here is based on a previous model used for wood particle pyrolysis. The combustion properties of black liquor have recently been studied. 7 refs., 5 figs., 1 tab.

Saastamoinen, J. [Technical Research Centre of Finland. Combustion and Thermal Engineering Lab., Jyvaeskylae (Finland)

1993-12-31

112

Flash pyrolysis at high temperature of ligno-cellulosic biomass and its components - production of synthesis gas; Pyrolyse flash a haute temperature de la biomasse ligno-cellulosique et de ses composes - production de gaz de synthese  

Energy Technology Data Exchange (ETDEWEB)

Pyrolysis is the first stage of any thermal treatment of biomass and governs the formation of synthesis gas for the production of electricity, hydrogen or liquid fuels. The objective of this work is to establish a link between the composition of a biomass and its pyrolysis gas. We study experimental flash pyrolysis and fix the conditions in which quantities of gas are maximal, while aiming at a regime without heat and mass transfer limitations (particles about 100 {mu}m): temperature of 950 C and residence time of about 2 s. Then we try to predict gas yields of any biomass according to its composition, applicable in this situation where thermodynamic equilibrium is not reached. We show that an additivity law does not allow correlating gas yields of a biomass with fractions of cellulose, hemi-cellulose and lignin contained in this biomass. Several explanations are suggested and examined: difference of pyrolytic behaviour of the same compound according to the biomass from which it is extracted, interactions between compounds and influence of mineral matter. With the aim of industrial application, we study pyrolysis of millimetric and centimetric size particles, and make a numerical simulation of the reactions of pyrolysis gases reforming. This simulation shows that the choice of biomass affects the quantities of synthesis gas obtained. (author)

Couhert, C

2007-11-15

113

Catalytic pyrolysis using UZM-44 aluminosilicate zeolite  

Energy Technology Data Exchange (ETDEWEB)

A new family of aluminosilicate zeolites designated UZM-44 has been synthesized. These zeolites are represented by the empirical formula. Na.sub.nM.sub.m.sup.k+T.sub.tAl.sub.1-xE.sub.xSi.sub.yO.sub.z where "n" is the mole ratio of Na to (Al+E), M represents a metal or metals from zinc, Group 1, Group 2, Group 3 and or the lanthanide series of the periodic table, "m" is the mole ratio of M to (Al+E), "k" is the average charge of the metal or metals M, T is the organic structure directing agent or agents, and E is a framework element such as gallium. The process involves contacting a carbonaceous biomass feedstock with UZM-44 at pyrolysis conditions to produce pyrolysis gases comprising hydrocarbons. The catalyst catalyzes a deoxygenation reaction converting oxygenated hydrocarbons into hydrocarbons and removing the oxygen as carbon oxides and water. A portion of the pyrolysis gases is condensed to produce low oxygen biomass-derived pyrolysis oil.

Nicholas, Christopher P; Boldingh, Edwin P

2014-04-29

114

Pyrolysis of peat: a comprehensive review of the literature  

Energy Technology Data Exchange (ETDEWEB)

All aspects of the pyrolysis of peat are discussed. The products of peat pyrolysis are a solid carbonaceous residue, a liquid distillate, and a non-condensable gas. Some of these include coke, semi-coke, and peat tar. Some parameters governing the pyrolysis of peat include temperature, contact time, heat pretreatment, heating rate, pressure, and particle size. Other aspects of peat pyrolysis covered are reaction kinetics, reaction intermediates, catalysts, and pyrolysis in the presence of various gases.

Roy, C.; Chornet, E.; Fuchsman, C.H.

1983-12-01

115

Temperature-dependent benzoic acid elimination mechanisms in pyrolysis of (-)-cocaine  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The thermal elimination of benzoic acid from (-)-cocaine is shown to be temperature-dependent. In the temperature range of 200-500 C only a trans-elimination is observed leading to methylecgonidine. Above ca. 500 C a second mechanism, the cis-elimination, comes up yielding a novel alkaloid methylisoecgonidine which has been characterized by means of mass spectrometry. At 600 C the cis-elimination predominates. The trans-elimination is postulated a two-step process consisting of a 1,7- a...

2011-01-01

116

Temperature-dependent benzoic acid elimination mechanisms in pyrolysis of (-)-cocaine  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english The thermal elimination of benzoic acid from (-)-cocaine is shown to be temperature-dependent. In the temperature range of 200-500 C only a trans-elimination is observed leading to methylecgonidine. Above ca. 500 C a second mechanism, the cis-elimination, comes up yielding a novel alkaloid methyli [...] soecgonidine which has been characterized by means of mass spectrometry. At 600 C the cis-elimination predominates. The trans-elimination is postulated a two-step process consisting of a 1,7- and a 1,5-hydrogen shift. The chemistry of cocaine base smoking is explained using the theory of chemical activation.

Novk, Michal.

117

Shape diversity in particles obtained by low temperature pyrolysis of ferrocene  

Energy Technology Data Exchange (ETDEWEB)

Synthesis experiments, made in a hermetically closed steel container through pyrolytical decomposition of various mixtures like ferrocene and xylene; ferrocene and water; ferrocene, xylene and water in different ratios have resulted in emergence of different in shape particles. The necessary for the realization of each experiment temperature increases linearly with 20 K/min up to the needed temperature and decreases mostly with no delay with a cooling rate of 30 K/min down to room temperature. The obtained particles are shaped as spheres, entirely or partially finished octahedrons or resemble stars. The spheres are perfect in shape and consist of pure incompletely graphitized carbon. The octahedron and star-like shaped particles, synthesized in the presence of ferrocene as precursor, have magnetite nuclei and carbon coating. Particle morphology has been examined by Scanning (SEM) and Transmission Electron Microscopy (TEM) and their chemical composition and crystal structure by the means of X-ray diffraction (XRD), Moessbauer spectroscopy and Electron Probe X-ray Micro Analysis and Energy Dispersive X-ray Spectrometry (EDS). Based on the results obtained it has been concluded that the synthesized particle morphology depends on the simultaneous proceeding magnetite crystal growing and crystal coating with partially graphitized carbon deposit. (copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

Koprinarov, N.; Konstantinova, M. [Central Lab of Solar Energy and New Energy Sources - Bulgarian Academy of Sciences (Bulgaria)

2011-07-15

118

An experimental study of fragmentation of coals during fast pyrolysis at high temperature and pressure  

Energy Technology Data Exchange (ETDEWEB)

An experimental apparatus has been developed in order to perform tests of primary fragmentation of solid fuels under severe heating conditions (up to 2200 K and 12 bar). Particles are laid on the strip and pyrolyzed under inert conditions, fragments are recovered and analyzed by a laser granulometer to assess the fragmentation propensity of the fuel. Experiments have been carried out at temperatures between 1400 K and 1900 K, heating rate of 5000 K/s, pressure in the range 1-12 bar. Four different coals have been studied: Gracem, Venezuelan, Omsky, and Kleincopje, classified respectively as anthracite, high and medium volatile bituminous coals. Results show that primary fragmentation at high heating rate and high temperature may result in the formation of relatively coarse fragments and sometimes in a multitude of fines. The probability of fragmentation and the propensity to form coarse versus small fragments varies from coal to coal. For a given coal fragmentation increases monotonously with temperature, whereas the effect of pressure is nonmonotonous. The role of different chemico-physical properties of coals on the pattern and the extent of primary fragmentation is discussed, in particular volatile matter content, ash melting point, rigidity and porosity of the carbon structure and swelling index. 30 refs., 8 figs., 3 tabs.

O. Senneca; M. Urciuolo; R. Chirone; D. Cumbo [Istituto di Ricerche sulla Combustione, Naples (Italy)

2011-09-15

119

Influence of deposition temperature (T {sub s}), air flow rate (f) and precursors on cathodoluminescence properties of ZnO thin films prepared by spray pyrolysis  

Energy Technology Data Exchange (ETDEWEB)

Semiconducting metal oxide such as ZnO films were prepared by the spray pyrolysis technique on glass substrates. The cathodoluminescence properties of these films were investigated with respect to deposition temperature (T {sub s}) and air flow rate (f). The luminescent films had a polycrystalline hexagonal wurtzite-type structure. Cathodoluminescence intensity was critically dependent on substrate temperature and spray rate. The best films had three emissions: near ultra-violet (UV) band gap peak at 382 nm, a blue-green emission at 520 nm and a red emission at 672 nm. These films were deposited at optimum condition: T {sub s}=450 deg C and f=5 ml/min.

El Hichou, A. [Laboratoire de Microscopies et d' Etude des Nanostructures, Universite de Reims, UFR Sciences exactes, LMEN, Equipe d' Accueil No. 3799, B.P. 138, 21 rue Clement Ader, 51685 Reims cedex2 (France) and Departement de physique, Faculte des Sciences et Techniques Gueliz, Universite Cadi Ayyad, B.P. 549 Marrakech, Marocco (Morocco)]. E-mail: elhichou@fstg-marrakech.ac.ma; Addou, M. [Lab. d' Optoelectronique et de Physico-Chimie des materiaux, Faculte des Sciences, Universite Ibn Tofail, B.P. 133, Kenitra, Marocco (Morocco); Ebothe, J. [Laboratoire de Microscopies et d' Etude des Nanostructures, Universite de Reims, UFR Sciences exactes, LMEN, Equipe d' Accueil No. 3799, B.P. 138, 21 rue Clement Ader, 51685 Reims cedex2 (France); Troyon, M. [Laboratoire de Microscopies et d' Etude des Nanostructures, Universite de Reims, UFR Sciences exactes, LMEN, Equipe d' Accueil No. 3799, B.P. 138, 21 rue Clement Ader, 51685 Reims cedex2 (France)

2005-06-15

120

Simple sample cell for deoxygenation of surfactant solutions  

International Nuclear Information System (INIS)

A simple gas bubbling system for removal of dissolved oxygen in micellar and surfactant solutions is described. The cell design allows for a continuous rapid flow of a purge gas through a surfactant solution without loss of fluid in spite of severe foaming. A long-necked cell with a conical top causes the bubbles to rupture without overflowing, and the fluid returns to the bulk solution. The cell offers numerous advantages over freeze pump thaw and other methods of deoxygenation in terms of speed, ease of sample preparation, and cost

1982-01-01

 
 
 
 
121

Determination of deoxyhemoglobin S polymer in sickle erythrocytes upon deoxygenation.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We have used 13C/1H magnetic double-resonance spectroscopy to measure the amount of sickle hemoglobin polymer within sickle erythrocytes as a function of oxygen saturation. We previously showed that the methods of cross-polarization and scalar decoupling could be used to measure accurately the polymer fraction in deoxygenated sickle hemoglobin solutions [Noguchi, C.T., Torchia, D.A. & Schechter, A.N. (1979) Proc. Natl. Acad. Sci. USA 76, 4936-4940]. Our measurements show that the amount of in...

1980-01-01

122

The pyrolysis of a tungsten alkyne complex as a low temperature route to tungsten carbide  

International Nuclear Information System (INIS)

The synthesis of designed organometallic compounds and their selective activation and transformation into materials of high purity (for electronic applications), high strength and/or high temperature stability (for refractory or structural applications), represents a potential area of extreme growth in organometallic chemistry. Research in this area could provide entirely new, inexpensive, fabrication methods for common and exotic materials. In this paper, the authors develop design principles for the preparation of organometallic precursors, ''premetallics'' that can be selectively converted, in high yields, to a desired refractory metal. They also describe preliminary efforts to prepare tungsten carbides (WC/sub x/) from a prematallic

1986-01-01

123

Effect of low-temperature oxidation on the pyrolysis and combustion of whole oil  

International Nuclear Information System (INIS)

Low-temperature oxidation (LTO) of the Fosterton crude oil mixed with its reservoir sand has been investigated in a tubular reactor. Reservoir sand saturated with 15 wt% of crude oil (20.5o API gravity) was subjected to air injection at low-temperature (220 oC) for a period of time (17 h and 30 min), resulting in the formation of an oxygenated hydrocarbon fuel. The vent gases were analyzed for the content of CO, CO2, and oxygen and the residue was analyzed to determine the elemental composition and calorific value. The presence of LTO region was verified from the values of apparent H/C ratio. In addition, thermal behavior and combustion kinetics of the residue was investigated using thermogravimetric analysis (TGA). TG involves both non-isothermal and isothermal analysis and kinetic data was derived from isothermal studies. The general model for nth order reaction was used to obtain the kinetic parameters of the coke oxidation reaction. The activation energy, frequency factor and order of the reactions were determined using the model.

2010-05-01

124

Copyrolysis of Seyitomer-lignite and safflower seed: influence of the blending ratio and pyrolysis temperature on product yields and oil characterization  

Energy Technology Data Exchange (ETDEWEB)

Pyrolytic behaviors of biomass/coal mixtures were investigated under a heating rate of 7{sup o}C min{sup -1}, over a range of pyrolysis temperatures between 400 and 700{sup o}C, and the blending ratio of coal in mixtures was varied between 0 and 100 wt %. The results indicated that considerable synergistic effects were observed during the copyrolysis in a fixed-bed reactor leading to an increase in the oil yield at lower than coal blending ratios of 33%. At the lower blending coal ratio conditions, the oil yields are higher than the expected ones, calculated as the sum of oil fractions produced by pyrolysis of each separated component. The maximum pyrolysis oil yield of 39.5% was obtained with 5% of lignite mixed with safflower seed. The obtained oils are characterized by Fourier transform infrared spectroscopy, {sup 1}H nuclear magnetic resonance, gas chromatography mass spectrometry, and elemental analysis. These findings can potentially help to understand and predict the behavior of coal/biomass blends in practical liquefaction systems. 33 refs., 8 figs., 4 tabs.

Ozlem Onay; Evren Bayram; O. Mete Kockar [Anadolu University, Eskisehir (Turkey). Porsuk Vocational School

2007-09-15

125

Chemical decomposition of iron in Spanish coal pyrolysis identified by Moessbauer spectroscopy at different temperatures  

Energy Technology Data Exchange (ETDEWEB)

Three chars from lignite (Se), sub bituminous (AA6), bituminous (BCA) Spanish coals produced at 673 K, 773 K, and 873 K were analyzed by Moessbauer spectroscopy at room temperature, and 80 K, except BCA char produced at 873 K, its analysis was extended down to 10 K. Least square fit analysis for the spectra of Se chars showed that, jarosite/Fe{sup 3+} was hydrolyzed into rozenite/Fe2+ at 873 K. Pyrite was reduced to troilite (FeS) at 773 K. Both jarosite and very broad doublet were observed at T = 673 K. The hyperfine parameters of this phase gave close values to microcrystalline iron in either Fe (II) or Fe (III) states. On the other hand, the spectral analysis of AA6 chars ascertained that rozenite was hydrolyzed to goethite (FeOOH) in the range of 773 K-873 K, whereas pyrite was reduced to pyrrohotite (Fe{sub 1-x}S). However, no chemical changes were observed for jarosite in all AA6-chars. Likewise, siderite was changed into magnetite in the BCA chars produced at 673 K and 773 K. Spectrum performed at 10 K for char produced at 873 K proved the presence of ferrihydrite (H = 489.2 kOe), troilite (H = 355.3 kOe) and a broad paramagnetic doublet belonging to an organic iron. These phases and still remaining siderite inferred also that such transformations are incomplete.

Ahmed, M.A.; Blesa, M.J.; Moliner, R. [Taif University, El Taif (Saudi Arabia). Faculty of Science

2007-07-01

126

Pyrolysis and oxidative pyrolysis experiments with organization exchange resin  

Energy Technology Data Exchange (ETDEWEB)

Pyrolysis may be an important pretreatment step before vitrification in a cold crucible melter (CCM). During vitrification of organic resin the carbon or other remaining residues may harm the performance of the cold crucible melter of the eventual stability of the final glass product. Hence, it is important to reduce or prevent such harmful waste from entry into the cold crucible melter. Pretreatment with pyrolysis will generally provide volume reduction resulting in less amount of solid waste that needs to be handled by the CCM; in addition, the pyrolytic processes may breakdown much of the complex organics causing release through volatilization resulting in less carbon and other harmful substances. Hence, KEPRI has undertaken studies on the pyrolysis and oxidative pyrolysis of organic ion exchange resin. Pyrolysis and oxidative pyrolysis were examined with TGA and a tube furnace. TGA results for pyrolysis with the flow of nitrogen indicate that even after pyrolyzing from room temperature to about 900 deg C, a significant mass fraction of the original cationic resin remains, approximately 46 %. The anionic resin when pyrolytically heated in a flow of nitrogen only, from room temperature to about 900 deg C, produced a final residue mass fraction of about 8 percent. Oxidation at a ratio of air to nitrogen, 1:2, reduced the cationic resin to 5.3% when heated at 5 C/min. Oxidation of anionic resin at the same ratio and same heating rate left almost no solid residue. Pyrolysis (e.g. nitrogen-only environment) in the tube furnace of larger samples relative to the TGA produced very similar results to the TGA. The differences may be attributed to the scale effects such as surface area exposure to the gas stream, temperature distributions throughout the resin, etc. (author) 7 refs., 7 figs.

Chun, Ung Kyung [Korea Electric Power Research Insititute, Taejon (Korea, Republic of)

1997-12-31

127

Experience on resin pyrolysis  

International Nuclear Information System (INIS)

The Swedish State Power Board has together with Nukem, Hanau, West-Germany carried out pyrolysis o powder resins in a pilot plant with a capacity of about 30 kg/hr. The pyrolysis reactor with its afterburner and offgas scrubber system has been operated under steady state condition. About 2200 kg resins have been pyrolysed under November-December 1983 and the decontamination factor for Cs has been measured. Solidification of the residues from the pyrolysis reactor and scrubber water solutions has been carried out and various recipes with cement have been tested. The pyrolysis process has high decontamination factors and no offgas problems as the operating temperature of the reactor is Low. The residues from the reactor are chemically dead and can not cause swelling problems. Compared with a normal cementation process the final waste volume will be reduced with a factor of 4 if also the scrubber water after neutralization is solidified. The reduction factor will be 5 if the scrubber water after neutralization is evaporated to a dry salt

1984-01-01

128

A new approach for reduction of methylene green withascorbic acid by de-oxygenation through carbondioxide  

Directory of Open Access Journals (Sweden)

Full Text Available Reduction kinetics of the methylene green (MG with ascorbic acid (AA in acidic medium at ?max 660 nm was monitored through visible spectrophotomtry in absence and presence of sodium carbonate. CO2 release through reaction of sodium carbonate and oxalic acid, created deoxygenated atmosphere for reduction of dye which greatly boosted the reaction rate. Initially slow reaction in presence of atmospheric oxygen proceeded rapidly when sodium carbonate was added. The reaction followed fractional order kinetics with AA and zero order kinetics with MG. The rate of reaction shows no linear dependence on [H+] concentration as an acidic medium. The rate of reaction is directly related with the elevated concentration of salt, which suggests that the two same charged species are involved in the rate determining step. Secondary reactions at elevated temperature showed complex kinetics.

Rafia Azmat

2011-07-01

129

Pyrolysis of waste for vitrification  

International Nuclear Information System (INIS)

Pyrolysis may be an important pretreatment step before vitrification in a cold crucible melter (CCM). During vitrification of organic resin the carbon or other remaining residues may harm the performance of the cold crucible melter or the eventual stability of the final glass product. Hence, it is important to reduce or prevent such harmful waste from entry into the cold crucible melter. Pretreatment with pyrolysis will generally provide volume reduction resulting in less amount of solid waste that needs to be handled by the CCM; in addition, the pyrolytic processes may breakdown much of the complex organics causing release through volatilization resulting in less carbon and other harmful substances. Hence, KEPRI has undertaken studies on the pyrolysis and oxidative pyrolysis of organic ion exchange resin. Pyrolysis and oxidative pyrolysis were examined with TGA and a tube furnace. TGA results for pyrolysis with the flow of nitrogen indicate that even after pyrolyzing from room temperature to about 900 .deg., a significant mass fraction of the original cationic resin remains, approximately 46%. The anionic resin when pyrolytically heated in a flow of nitrogen only, from room temperature to about 900 .deg., produced a final residue mass fraction of about 8 percent. Oxidation at a ratio of air to nitrogen, 1:2, reduced the cationic resin to 5.3% when heated at 5 C/min. Oxidation of anionic resin at the same ratio and same heating rate left almost no solid residue. Pyrolysis (e.g. nitrogen-only environment) in the tube furnace of larger samples relative to the TGA produced very similar results to the TGA. The differences may be attributed to the scale effects such as surface area exposure to the gas stream, temperature distributions throughout the resin, etc

1997-11-06

130

Pyrolysis of tyres. Influence of the final temperature of the process on emissions and the calorific value of the products recovered  

International Nuclear Information System (INIS)

A study was made of the pyrolysis of tyre particles, with the aim of determining the possibilities of using the products resulting from the process as fuel. Three final temperatures were used, determined from thermogravimetric data. The design of the experiment was a horizontal oven containing a reactor into which particles of the original tyre were placed. After the process, a solid fraction (char) remained in the reactor, while the gases generated went through a set of scrubbers where most of the condensable fraction (oils) was retained. Finally, once free of this fraction, the gases were collected in glass ampoules. Solid and liquids fractions were subjected to thermogravimetric analyses in order to study their combustibility. The gas fraction was analysed by means of gas chromatography to establish the content of CO, CO2, H2 and hydrocarbons present in the samples (mainly components of gases produced in the pyrolysis process). A special study was made of the sulphur and chlorine content of all the fractions, as the presence of these elements could be problematic if the products are used as fuel. Tyre pyrolysis engenders a solid carbon residue that concentrates sulphur and chorine, with a relatively high calorific value, although not so high as that of the original tyre. The liquid fraction produced by the process has a high calorific value, which rises with the final temperature, up to 40 MJ/kg. The chlorine content of this fraction is negligible. Over 95% of the gas fraction, regardless of the final temperature, is composed of hydrocarbons of a low molecular weight and hydrogen, this fraction also appearing to be free of chlorine

2004-01-01

131

Pyrolysis of tyres. Influence of the final temperature of the process on emissions and the calorific value of the products recovered.  

Science.gov (United States)

A study was made of the pyrolysis of tyre particles, with the aim of determining the possibilities of using the products resulting from the process as fuel. Three final temperatures were used, determined from thermogravimetric data. The design of the experiment was a horizontal oven containing a reactor into which particles of the original tyre were placed. After the process, a solid fraction (char) remained in the reactor, while the gases generated went through a set of scrubbers where most of the condensable fraction (oils) was retained. Finally, once free of this fraction, the gases were collected in glass ampoules. Solid and liquids fractions were subjected to thermogravimetric analyses in order to study their combustibility. The gas fraction was analysed by means of gas chromatography to establish the content of CO, CO2, H2 and hydrocarbons present in the samples (mainly components of gases produced in the pyrolysis process). A special study was made of the sulphur and chlorine content of all the fractions, as the presence of these elements could be problematic if the products are used as fuel. Tyre pyrolysis engenders a solid carbon residue that concentrates sulphur and chorine, with a relatively high calorific value, although not so high as that of the original tyre. The liquid fraction produced by the process has a high calorific value, which rises with the final temperature, up to 40 MJ/kg. The chlorine content of this fraction is negligible. Over 95% of the gas fraction, regardless of the final temperature, is composed of hydrocarbons of a low molecular weight and hydrogen, this fraction also appearing to be free of chlorine. PMID:15120430

Dez, C; Martnez, O; Calvo, L F; Cara, J; Morn, A

2004-01-01

132

Pyrolysis of scrap tyres  

Energy Technology Data Exchange (ETDEWEB)

Cross-section samples (2-3 cm wide), representative of a whole car tyre, have been pyrolysed under nitrogen in a 3.5 dm{sup 3} autoclave at 300C, 400C, 500C, 600C and 700C. The whole solid, liquid and gaseous products generated during each pyrolysis were collected and characterised. No significant influence of temperature on the amount and characteristics of pyrolysis products was observed over 500C. Tyre-pyrolysis liquids are a complex mixture of C{sub 5}-C{sub 20} organic compounds, with a great proportion of aromatics. They have high gross calorific values, GCV (42 MJ kg{sup -1}) and N and S contents (0.4% and 1.2%, respectively) within those specified for certain heating fuels. About 30 wt.% of such liquids is an easily distillable fraction with boiling points (70-210C) in the range of commercial petrol, and about 60 wt.% of them have the boiling point range (150-370C) typical of diesel oil. Pyrolysis gases are composed of hydrocarbons of which C{sub 1} and C{sub 4} are predominant, together with some CO, CO{sub 2} and SH{sub 2}; they have very high gross calorific values (68-84 MJ m{sup -3}). Tyre-pyrolysis residues have equal dimensions as the original tyre portion and are easily disintegrable into black powder and steel cords. The black powder has surface areas comparable to those of commercial carbon blacks, but it has a great proportion of ash and impurities (12 wt.%), which are the inorganic fillers added to tyre rubber; it may have a potential use as semireinforcing or nonreinforcing carbon black.

De Marco Rodriguez, I.; Laresgoiti, M.F.; Cabrero, M.A.; Torres, A.; Chomon, M.J.; Caballero, B. [Escuela Superior de Ingenieros de Bilbao, Alda. Urquijo s/n, 48013 Bilbao (Spain)

2001-08-01

133

Pyrolysis process for producing fuel gas  

Science.gov (United States)

Solid waste resource recovery in space is effected by pyrolysis processing, to produce light gases as the main products (CH.sub.4, H.sub.2, CO.sub.2, CO, H.sub.2O, NH.sub.3) and a reactive carbon-rich char as the main byproduct. Significant amounts of liquid products are formed under less severe pyrolysis conditions, and are cracked almost completely to gases as the temperature is raised. A primary pyrolysis model for the composite mixture is based on an existing model for whole biomass materials, and an artificial neural network models the changes in gas composition with the severity of pyrolysis conditions.

Serio, Michael A. (Inventor); Kroo, Erik (Inventor); Wojtowicz, Marek A. (Inventor); Suuberg, Eric M. (Inventor)

2007-01-01

134

Pyrolysis processing for solid waste resource recovery  

Science.gov (United States)

Solid waste resource recovery in space is effected by pyrolysis processing, to produce light gases as the main products (CH.sub.4, H.sub.2, CO.sub.2, CO, H.sub.2O, NH.sub.3) and a reactive carbon-rich char as the main byproduct. Significant amounts of liquid products are formed under less severe pyrolysis conditions, and are cracked almost completely to gases as the temperature is raised. A primary pyrolysis model for the composite mixture is based on an existing model for whole biomass materials, and an artificial neural network models the changes in gas composition with the severity of pyrolysis conditions.

Serio, Michael A. (Inventor); Kroo, Erik (Inventor); Wojtowicz, Marek A. (Inventor); Suuberg, Eric M. (Inventor)

2007-01-01

135

Oxidation and low temperature properties of biofuels obtained from pyrolysis and alcoholysis of soybean oil and their blends with petroleum diesel  

Energy Technology Data Exchange (ETDEWEB)

Diesel-like fuels were synthesized by a pyrolysis method using soybean oil (pyrodiesel, PD) and soybean soapstock (SPD), respectively, as starting material. These pyrodiesel samples were compared with soy biodiesel (BD) samples. All these three biofuels (PD, SPD and BD) and their blends with high sulfur (HSD) and low sulfur (LSD) diesel fuels were evaluated by measuring a number of fuel properties, such as oxidative stability, low-temperature performance, acid value and corrosion properties. Compared to BD blends, PD and SPD and their blends were found to have better oxidative stability, though inferior acid values. SPD and its blends have better flow performance at low-temperature compared to BD and PD blends. All the biofuels and their blends met the copper corrosion requirement prescribed by US and European standard. Based on the results reported here, pyrodiesels from these two-different feedstocks have potential and will require some upgrading or change in pyrolysis conditions, if they are to be used as fuel blending component. (author)

Sharma, Brajendra K. [Food and Industrial Oil Research Unit, National Center for Agricultural Utilization Research, United States Department of Agriculture, Agricultural Research Service, 1815N. University St., Peoria, IL 61604 (United States); Department of Chemical Engineering, The Pennsylvania State University, University Park, PA 16802 (United States); Suarez, Paulo A.Z. [Food and Industrial Oil Research Unit, National Center for Agricultural Utilization Research, United States Department of Agriculture, Agricultural Research Service, 1815N. University St., Peoria, IL 61604 (United States); LMC-IQ, Universidade de Brasilia, CP 4478, CEP 70919-970, Brasilia-DF (Brazil); Perez, Joseph M. [Department of Chemical Engineering, The Pennsylvania State University, University Park, PA 16802 (United States); Erhan, Sevim Z. [Food and Industrial Oil Research Unit, National Center for Agricultural Utilization Research, United States Department of Agriculture, Agricultural Research Service, 1815N. University St., Peoria, IL 61604 (United States)

2009-10-15

136

Controlled air pyrolysis incinerator  

International Nuclear Information System (INIS)

An advanced controlled air pyrolysis incinerator has been researched, developed and placed into commercial operation for both radioactive and other combustible wastes. Engineering efforts cocentrated on providing an incinerator which emitted a clean, easily treatable off-gas and which produced a minimum amount of secondary waste. Feed material is continuously fed by gravity into the system's pyrolysis chamber without sorting, shredding, or other such pretreatment. Metal objects, liquids such as oil and gasoline, or solid products such as resins, blocks of plastic, tire, animal carcasses, or compacted trash may be included along with normal processed waste. The temperature of the waste is very gradually increased in a reduced oxygen atmosphere. Volatile pyrolysis gases are produced, tar-like substances are cracked and the resulting product, a relatively uniform, easily burnable material, is introduced into the combustion chamber. Steady burning is thus accomplished under easily controlled excess air conditions with the off-gasthen passing through a simple dry clean-up system. Gas temperatures are then reduced by air dilution before passing through final HEPA filters. Both commercial and nuclear installations have been operated with the most recent application being the central incinerator to service West Germany's nuclear reactors

1982-04-22

137

Alveolar gas exchange, oxygen delivery and tissue deoxygenation in men and women during incremental exercise.  

Science.gov (United States)

We investigated whether leg and arm skeletal muscle, and cerebral deoxygenation, differ during incremental cycling exercise in men and women, and if women's lower capacity to deliver O2 affects tissue deoxygenation. Men (n=10) compared to women (n=10), had greater cardiac output, which with greater hemoglobin concentration produced greater absolute (QaO2) and body size-adjusted oxygen delivery (QaO2i) at peak exercise. Despite women's lower peak QaO2, their leg muscle deoxygenation was similar at a given work rate and QaO2, but less than in men at peak exercise (?tissue saturation index -27.1 13.2% vs. -11.8 5.7%, P<0.01; ?[deoxyhemoglobin] 15.03 8.57 ?M vs. 3.73 3.98 ?M, P<0.001). At peak exercise, oxygen uptake was associated both with QaO2 and leg muscle deoxygenation (both P<0.01). Arm muscle and cerebral deoxygenation did not differ between sexes at peak exercise. Thus, both high O2 delivery and severe active muscle deoxygenation are determinants of good exercise performance, and active muscle deoxygenation responses are regulated partly in a sex-specific manner with an influence of exercise capacity. PMID:23707876

Peltonen, Juha E; Hgglund, Harriet; Koskela-Koivisto, Tiina; Koponen, Anne S; Aho, Jyrki M; Rissanen, Antti-Pekka E; Shoemaker, J Kevin; Tiitinen, Aila; Tikkanen, Heikki O

2013-08-15

138

Characteristics of liquid product from the pyrolysis of waste plastic mixture at low and high temperatures: Influence of lapse time of reaction  

International Nuclear Information System (INIS)

Pyrolysis of a waste plastic mixture (high-density polyethylene: low-density polyethylene: polypropylene: polystyrene = 3:2:3:1) into a liquid product was carried out in a stirred semi-batch reactor at low (350 deg. C) and high (400 deg. C) temperatures. The effect of lapse time of reaction in the reactor and also degradation temperature on the characteristics of the liquid product from pyrolysis of the mixture was investigated. Liquid products were described by cumulative amount distribution, paraffin, olefin, naphthene and aromatic (PONA) distribution and molecular weight distribution. Their characteristic was quite differed with a lapse time of reaction and also at a low and high degradation temperatures, because of the different physicochemical properties of the plastic types in the mixture. With increase of lapse time of reaction, the order for the main products in PONA components obtained at 350 deg. C was firstly aromatic products and then olefin products, while at 400 deg. C the order was firstly aromatic products, then olefin products and finally paraffin products. The experiments also showed from the molecular weight distribution of liquid PONA components that the paraffin and olefin products had a wide distribution by mainly random scission of polymer, but in the case of olefin products were produced by an end-chain scission mechanism as well as random scission mechanism, as evidenced by much more light olefin products. This phenomenon was evident at a higher degradation temperature. Also, both the light olefin and naphthene products with a molecular weight of around 120, as a main product, showed a similar trend as a function of lapse time, which had a maximum fraction at 343 min (at 350 deg. C) and 83 min (at 400 deg. C). Among PONA components, the highest concentrations of aromatic products were obtained with a molecular weight of around 100 at the fastest lapse time of reaction, regardless of degradation temperature. It was concluded that the characteristics of liquid product on the pyrolysis of plastic mixtures were strongly influenced by lapse time of reaction and degradation temperature

2007-01-01

139

Effect of the substrate temperature on the physical properties of molybdenum tri-oxide thin films obtained through the spray pyrolysis technique  

Energy Technology Data Exchange (ETDEWEB)

Polycrystalline molybdenum tri-oxide thin films were prepared using the spray pyrolysis technique; a 0.1 M solution of ammonium molybdate tetra-hydrated was used as a precursor. The samples were prepared on Corning glass substrates maintained at temperatures ranging between 423 and 673 K. The samples were characterized through micro Raman, X-ray diffraction, optical transmittance and DC electrical conductivity. The species MoO{sub 3} (H{sub 2}O){sub 2} was found in the sample prepared at a substrate temperature of 423 K. As the substrate temperature rises, the water disappears and the samples crystallize into {alpha}-MoO{sub 3}. The optical gap diminishes as the substrate temperature rises. Two electrical transport mechanisms were found: hopping under 200 K and intrinsic conduction over 200 K. The MoO{sub 3} films' sensitivity was analyzed for CO and H{sub 2}O in the temperature range 160 to 360 K; the results indicate that CO and H{sub 2}O have a reduction character. In all cases, it was found that the sensitivity to CO is lower than that to H{sub 2}O. - Highlights: Black-Right-Pointing-Pointer A low cost technique is used which produces good material. Black-Right-Pointing-Pointer Thin films are prepared using ammonium molybdate tetra hydrated. Black-Right-Pointing-Pointer The control of the physical properties of the samples could be done. Black-Right-Pointing-Pointer A calculation method is proposed to determine the material optical properties. Black-Right-Pointing-Pointer The MoO{sub 3} thin films prepared by spray pyrolysis could be used as gas sensor.

Martinez, H.M. [Grupo de Materiales con Aplicaciones Tecnologicas, Departamento de Fisica Universidad Nacional de Colombia sede Bogota (Colombia); Torres, J., E-mail: njtorress@unal.edu.co [Grupo de Materiales con Aplicaciones Tecnologicas, Departamento de Fisica Universidad Nacional de Colombia sede Bogota (Colombia); Lopez Carreno, L.D. [Grupo de Materiales con Aplicaciones Tecnologicas, Departamento de Fisica Universidad Nacional de Colombia sede Bogota (Colombia); Rodriguez-Garcia, M.E. [Departamento de Nanotecnologia, Centro de Fisica Aplicada y Tecnologia Avanzada, Universidad Nacional Autonoma de Mexico, Campus Juriquilla, Queretaro, Qro., Mexico (Colombia)

2013-01-15

140

Vapor phase pyrolysis  

Science.gov (United States)

The vapor phase pyrolysis process is designed exclusively for the lunar production of oxygen. In this concept, granulated raw material (soil) that consists almost entirely of metal oxides is vaporized and the vapor is raised to a temperature where it dissociates into suboxides and free oxygen. Rapid cooling of the dissociated vapor to a discrete temperature causes condensation of the suboxides, while the oxygen remains essentially intact and can be collected downstream. The gas flow path and flow rate are maintained at an optimum level by control of the pressure differential between the vaporization region and the oxygen collection system with the aid of the environmental vacuum.

Steurer, Wolfgang

1992-01-01

 
 
 
 
141

Upgrading of flash pyrolysis oil and utilization in refineries  

Energy Technology Data Exchange (ETDEWEB)

Flash pyrolysis oil from an ENSYN RTP pilot plant was upgraded in a continuous bench scale unit with commercial CoMo and NiMo catalysts in anticipation of scaling up the process. Large amounts of product were produced in a pilot plant for use in an extended analytical characterisation programme. In bench-scale experiments, high deoxygenation rates of 88-99.9% were achieved. Low liquid and high water yields were obtained. The fractionated products of the production run did not fulfil the requirements for direct use as gasoline and diesel. The process is restricted by several operational problems such as rapid catalyst deactivation, coking and plugging. Due to high feedstock and hydrogen addition costs, pyrolysis upgraded oil by the process tested is significantly more expensive than petroleum-derived oil at present oil prices. (author)

Baldauf, W.; Balfanz, U.; Rupp, M. (Veba Oel Entwicklungsgesellschaft GmbH, Gelsenkirchen (Germany))

1994-01-01

142

Effects of hypoxia on the onset of muscle deoxygenation and the lactate threshold.  

Science.gov (United States)

Six subjects performed two trials of incremental cycling to exhaustion under normoxic and hypoxic conditions. The lactate threshold and onset of muscle deoxygenation were highly correlated under both conditions, and during the hypoxic condition both variables shifted leftward. PMID:16925891

Lorenz, Kent A; Hom, Clifford; Lopez, Jon; Pozos, Robert S; Buono, Michael J; Kolkhorst, Fred W

2006-08-01

143

Optimization of multi-stage pyrolysis  

International Nuclear Information System (INIS)

Pyrolysis process is considered as a beneficial option in waste treatment largely due to the products generated and the energy recovery when compared to other methods. In the conventional pyrolysis process, heat is continually supplied to the reactor until the final pyrolysis temperature is attained. The reactor is then maintained isothermally at this temperature until the pyrolysis is completed. This technique does not take into consideration the mechanism of the pyrolysis which involves both exothermic and endothermic reaction and the opportunity of gaining some processing benefits is often ignored. Multi-stage pyrolysis which is an approach to carry out pyrolysis with multiple heating stages in order to gain certain processing benefits has been introduced in our earlier works. 22.5% energy reduction was achieved in our past work with a 100% increase in completion time. This work therefore proposes the optimization of the operating parameters in multi-stage pyrolysis in order to limit the increase in completion time and also reduces the overall energy. This innovative approach can achieve a range of 24.7%37.9% reduction in energy usage with 37%50% increase in completion time depending on the heating rate for each heating stages. This approach has also been used for charcoal production

2013-10-15

144

Preparation and characterization of nanostructures of in-doped ZnO films deposited by chemically spray pyrolysis: Effect of substrate temperatures  

Science.gov (United States)

We deposited undoped (ZnO) and indium-doped ZnO (IZO) films onto glass substrate via ultrasonic spray pyrolysis technique. The variation in structural, surface morphology, electrical, optical and photoluminescent properties as a function of substrate temperature is investigated. X-rays pattern confirms that as-synthesized IZO phase is grown along a (002) preferential plane. Nanosized grains (films shows broadened nanostructures which have grown along c-axis and nanostructures are found to be smooth (RMS60 nm). Study by spectrophotometer reveals that the as-grown films are highly transparent in the visible and IR spectra (T 88%), and that the bandgap is slightly narrowed (3.17 eV). Electrical measurements confirm the enhancement of conductivity, ? films grown at 400 C. The photoluminescence analysis demonstrates strong yellow (2.1 eV) and blue (2.8 eV) light and weak green (2.3 eV) emissions.

Benhaliliba, M.; Benouis, C. E.; Mouffak, Z.; Ocak, Y. S.; Tiburcio-Silver, A.; Aida, M. S.; Garcia, A. A.; Tavira, A.; Sanchez Juarez, A.

2013-11-01

145

Modeling CFB biomass pyrolysis reactors  

International Nuclear Information System (INIS)

Fluidized bed-fast pyrolysis of biomass is considered as having a high commercial potential for the thermal treatment of biomass. This paper mainly presents a model developed further to improvements in the understanding of the science, and capable of predicting pyrolysis yields that are in satisfactory agreement with literature data. The kinetics and endothermicity of biomass pyrolysis are reviewed from extensive TGA and differential scanning calorimetry experiments. For most biomass species, the reaction rate constant is >0.5 s-1, corresponding to a fast reaction, so the requirement of a short reaction time for a high conversion can be met. Lab-scale batch experiments and pilot-scale CFB experiments show that an oil yield between 60 and 70 wt% can be achieved at an operating temperature of 51010 oC, in line with literature data. Pyrolysis fundamentals are the basis of the developed model, applied to predict the yields of the different products as functions of process operation variables. The predictions are in fair agreement with our own conversion experiments and literature data. Finally, all findings are used and are illustrated in the design strategy of a CFB for the pyrolysis of biomass

2008-02-01

146

Effect of Annealing Temperature on Structural, Optical and Electrical Properties of Pure CdS Thin Films Deposited by Spray Pyrolysis Technique  

Directory of Open Access Journals (Sweden)

Full Text Available

Effect of annealing temperature on the properties of CdS thin films are carried out in this work. Nanocrystalline cadmium sulphide (CdS thin films were prepared using spray pyrolysis deposition (SPD technique and the structural, optical and electrical properties were investigated for different annealing temperature (as deposited, 300, 400 & 500 C. The surface morphology and compositional properties studied by SEM and EDX respectively. The crystal structure of CdS thin film was studied by X-ray diffraction. The crystallite size and lattice constant of SPD CdS thin films were investigated. The optical parameters such as transmittance, absorption coefficient and energy band gap of the films with thermal annealing temperature was investigated by UV/VIS spectrophotometer. The variation of band gap values of CdS thin film samples were found to be in the range of 2.51 to 2.8 eV. Electrical resistivity measurements were carried out in fourprobe Vander Pauw method at different temperature. So CdS films may be a good candidate for suitable application in various optoelectronic devices.

2012-12-01

147

PYROLYSIS OF TOBACCO RESIDUE: PART 1. THERMAL  

Directory of Open Access Journals (Sweden)

Full Text Available The pyrolysis of two types of tobacco residue was carried out at different pyrolysis temperatures between 300 and 600 C and a residence time of 1 h in a nitrogen atmosphere. The effect of pyrolysis temperature on the product distributions was investigated and the composition of the bio-oils identified. The variation in product distribution depended on both the temperature and the type of tobacco residues. The maximum liquid yields were obtained at 400C for one sample and at 500C for the other. The compositions of bio-oils from the pyrolysis of the two samples were found to be very similar. N-containing compounds were found to be the major compounds identified in ether extracts for both samples.

Mehmet K. Akalin

2011-03-01

148

Corrosivity Of Pyrolysis Oils  

Energy Technology Data Exchange (ETDEWEB)

Pyrolysis oils from several sources have been analyzed and used in corrosion studies which have consisted of exposing corrosion coupons and stress corrosion cracking U-bend samples. The chemical analyses have identified the carboxylic acid compounds as well as the other organic components which are primarily aromatic hydrocarbons. The corrosion studies have shown that raw pyrolysis oil is very corrosive to carbon steel and other alloys with relatively low chromium content. Stress corrosion cracking samples of carbon steel and several low alloy steels developed through-wall cracks after a few hundred hours of exposure at 50 C. Thermochemical processing of biomass can produce solid, liquid and/or gaseous products depending on the temperature and exposure time used for processing. The liquid product, known as pyrolysis oil or bio-oil, as produced contains a significant amount of oxygen, primarily as components of water, carboxylic acids, phenols, ketones and aldehydes. As a result of these constituents, these oils are generally quite acidic with a Total Acid Number (TAN) that can be around 100. Because of this acidity, bio-oil is reported to be corrosive to many common structural materials. Despite this corrosive nature, these oils have the potential to replace some imported petroleum. If the more acidic components can be removed from this bio-oil, it is expected that the oil could be blended with crude oil and then processed in existing petroleum refineries. The refinery products could be transported using customary routes - pipelines, barges, tanker trucks and rail cars - without a need for modification of existing hardware or construction of new infrastructure components - a feature not shared by ethanol.

Keiser, James R [ORNL; Bestor, Michael A [ORNL; Lewis Sr, Samuel Arthur [ORNL; Storey, John Morse [ORNL

2011-01-01

149

Pyrolysis properties of stored biomass  

Energy Technology Data Exchange (ETDEWEB)

Degradation did occur in the interior region of the hybrid poplar wood piles. There was visual evidence that fungal activity was present in the interior of the wood chip piles that corroborates the results from the pyrolysis data. Even though the decrease in hybrid poplar pyrolysis oil heating value was small (4%) and the structural changes as indicated by the NMR slight, these changes would increase with a longer storage time or more severe storage environmental conditions. Unweathered portion of the switch-grass bales contains switch grass that is similar to fresh material. The large round bales also appear to form a storage package that minimizes weathering even under severe conditions. However, it is unclear because of the lack of data on switch-grass from the weathered portion of the bales if weathering of switch-grass will significantly impact pyrolysis production and products. The production of pyrolysis products and the composition of those products are significantly different between hybrid poplar and switch grass. The amount of oil produced from the two feedstocks is similar, but switch grass produces more char while the hybrid poplar produces more gas. Also, the oils differ in their make up based on the NMR and elemental analysis. These differences can be manipulated to best fit the pyrolysis system being used, and to maximize the capture of the highest value co- products or minimize harmful components in the oil. Of particular concern, is the high amount of potassium in the switch-grass pyrolysis oil. The potassium can form alkali metals or salts or complexes with low ash fusion temperatures that will result in slag forming on and in components of any combustion system used to convert the oil to energy. 11 refs, 1 fig, 2 tabs

Wiselogel, A.E.; Agblevor, F.A. [National Renewable Energy Lab., Golden, CO (United States)

1995-12-31

150

Suspension Combustion of Wood: Influence of Pyrolysis Conditions on Char Yield, Morphology, and Reactivity  

DEFF Research Database (Denmark)

Chars from pine and beech wood were produced by fast pyrolysis in an entrained flow reactor and by slow pyrolysis in a thermogravimetric analyzer. The influence of pyrolysis temperature, heating rate and particle size on char yield and morphology was investigated. The applied pyrolysis temperature varied in the range 673??1673 K for slow pyrolysis and between 873 and 1573 K for fast pyrolysis. The chars were oxidized in a thermogravimetric analyzer and the mass loss data were used to determine char oxidation reactivity. Char yield from fast pyrolysis (104??105 K/s) was as low as 1 to 6% on a dry ash free basis, whereas it was about 15??17% for slow pyrolysis (10??20 K/min); char yield decreased as pyrolysis temperature increased. During fast pyrolysis wood particles underwent melting, yet to different extents for the two investigated fuels: pine wood produced chars of porous spherical particles, whereas beech sawdust chars showed a somewhat less drastic change of morphology with respect to the parent fuel. Char produced by low heating rate pyrolysis fully retained the original fibrous structure of wood. Fast pyrolysis chars were significantly more reactive than slow pyrolysis chars; moreover, char oxidation reactivity decreased as pyrolysis temperature increased. The amount and composition of the ash forming matter of the wood fuels seems to play an important role in determining the differences in char yield, morphology and reactivity.

Dall'Ora, Michelangelo; Jensen, Peter Arendt

2008-01-01

151

Role of substrate temperature on the properties of Na-doped ZnO thin film nanorods and performance of ammonia gas sensors using nebulizer spray pyrolysis technique  

International Nuclear Information System (INIS)

Highlights: Na-doped ZnO films deposited on glass by nebulizer spray pyrolysis (NSP) method. NSP method for large area coatings and good results as compared with other methods. HR-SEM studies reveal the formation of Na-doped ZnO films consisting of nano-rods. Na-doped ZnO films ensure their stability and suitability for gas sensors. -- Abstract: Sodium doped zinc oxide (Na:ZnO) thin films were deposited on glass substrates at substrate temperatures 300, 400 and 500 C by a novel nebulizer spray method. X-ray diffraction shows that all the films are polycrystalline in nature having hexagonal structure with high preferential orientation along (0 0 2) plane. High resolution SEM studies reveal the formation of Na-doped ZnO films having uniformly distributed nano-rods over the entire surface of the substrates at 400 C. The complex impedance of the ZnO nano-rods shows two distinguished semicircles and the diameter of the arcs got decreased in diameter as the temperature increases from 170 to 270 C and thereafter slightly increased

2014-01-05

152

Role of substrate temperature on the properties of Na-doped ZnO thin film nanorods and performance of ammonia gas sensors using nebulizer spray pyrolysis technique  

Energy Technology Data Exchange (ETDEWEB)

Highlights: Na-doped ZnO films deposited on glass by nebulizer spray pyrolysis (NSP) method. NSP method for large area coatings and good results as compared with other methods. HR-SEM studies reveal the formation of Na-doped ZnO films consisting of nano-rods. Na-doped ZnO films ensure their stability and suitability for gas sensors. -- Abstract: Sodium doped zinc oxide (Na:ZnO) thin films were deposited on glass substrates at substrate temperatures 300, 400 and 500 C by a novel nebulizer spray method. X-ray diffraction shows that all the films are polycrystalline in nature having hexagonal structure with high preferential orientation along (0 0 2) plane. High resolution SEM studies reveal the formation of Na-doped ZnO films having uniformly distributed nano-rods over the entire surface of the substrates at 400 C. The complex impedance of the ZnO nano-rods shows two distinguished semicircles and the diameter of the arcs got decreased in diameter as the temperature increases from 170 to 270 C and thereafter slightly increased.

Mariappan, R., E-mail: marijpr@gmail.com [Department of Physics, Sri Ramakrishna Mission Vidyalaya College of Arts and Science, Coimbatore 641 020, Tamil Nadu (India); Department of Physics, Adhiyamaan College of Engineering, Hosur 635 109, Tamilnadu (India); Ponnuswamy, V.; Suresh, R. [Department of Physics, Sri Ramakrishna Mission Vidyalaya College of Arts and Science, Coimbatore 641 020, Tamil Nadu (India); Suresh, P. [Materials Research Centre, Indian Institute of Science, Bangalore 560 012 (India); Chandra Bose, A. [Department of Physics, National Institute of Technology, Tiruchirappalli 620 015, Tamil Nadu (India); Ragavendar, M. [Department of Physics, KPR Institute of Engineering and Technology, Coimbatore 641 407, Tamil Nadu (India)

2014-01-05

153

Phenomenological models of cellulose pyrolysis  

Energy Technology Data Exchange (ETDEWEB)

Using yields vs. residence time and temperature from 50 to 1000 ms and 650-900{sup o}C, measured with the ultra pyrolysis system at the University of Western Ontario (UWO) we established an approximate total gaseous yield function Y (t,T). With UWO data, we also establish approximate correlations between individual gaseous yields (CO, CO{sub 2}, C{sub 2}H{sub 4}, C{sub 2}H{sub 2}, C{sub 2}H{sub 6} and C{sub 3}H{sub 6}) and the total gaseous yield that could be used to give Y{sub i}(t,T) for individual gases. We further extend Y(t,T) using shock tube pyrolysis measurements from 0.3 to 2 ms and 900 to 2100{sup o}C made at Kansas State University (KSU). In doing so, we develop a global decay model that gives analytical time and temperature dependencies for cellulose, activated cellulose, tar, prompt total gas and late total gas. We next examine the impact of heating rates and transfer upon pyrolysis of cellulose using slow pyrolysis data obtained by thermogravimetric analysis at the Colarado School of Mines (CSM). In this effort, we first develop an accurate general relationship for Boltzmann integrals. Then using an analytically convenient Arrhenius reaction rate (ARR) we examine data at varying heating rates and with three Biot numbers. We find some phenomenological analytical relationships giving ARR parameter dependencies on heating rate and particle size that appear indicative of heat transfer impacts. If adequate data becomes available these relationships might be applied to hemicellulose and lignin. Then the pyrolysis rates of any plant species might be predicted in terms of the pyrolytic characteristics of their cellulose, hemicellulose and lignin components. (Author)

Green, A.E.S.; Zanardi, M.A.; Mullin, J.P. [Florida Univ., Gainesville, FL (United States). Combustion Lab.]|[Florida Univ., Gainesville, FL (United States). Dept. of Mechanical Engineering

1997-12-31

154

Mild pyrolysis of selectively oxidized coals  

Energy Technology Data Exchange (ETDEWEB)

The primary objective of this study is to investigate the removal organic sulfur from selectively oxidized Illinois coals using mild thermal/chemical processes. Work completed this quarter includes the investigation of the mild pyrolysis of unoxidized coals plus a selection of selectively oxidized coals. In addition the effect of particle size and extent of oxidation on pyrolysis was investigated. Some preliminary data concerning pyrolysis under vacuum and ambient pressure was also obtained. Work completed this quarter supports the following conclusions: (1) Desulfurization of unoxidized coals increases with increasing pyrolysis temperature and correlates with the loss of volatile matter. (2) Particle size did not influence the extent of desulfurization significantly. (3) Removing pyrite prior to pyrolysis helps to achieve a lower sulfur product beyond that expected from the removal of pyrite alone. (4) The extent of selective oxidation in teh pretreatment step did not effect the level of desulfurization obtained by pyrolysis alone. However this factor was important in the desulfurization obtained with supercritical methanol (SCM)/base. (5) Up to 84% of the sulfur has been removed from the IBC 101 coal by combining selective oxidation and SCM/base reactions. (6) Evidence for regressive reactions between volatilized sulfur compounds and partially desulfurized products was obtained by studying how changes in pyrolysis pressure effected the product sulfur content.

Hippo, E.J.

1991-01-01

155

Pyrolysis of spent ion-exchanger resins  

Energy Technology Data Exchange (ETDEWEB)

Initial tests have shown that ion exchangers (IEX) can be decomposed by pyrolysis with very good results, yielding an inert and chemically resistant product. No additives are necessary. The main constituent of the product, the pyrolysis residues or ash, is carbon. It has been discovered that the entire radioactive inventory remains in the pyrolysis residues during pyrolysis of the IEX. This is achieved by relatively low process temperatures that prevent highly volatile nuclides such as the caesium nuclides from passing into the gaseous phase. Sintered metal filters in pyrolysis plant ensure that even the radioactivity bonded to the dust remains in the pyrolysis residues. In addition to the radionuclides, the main constituents of the residue are carbon from the original polystyrene matrix and sulphur from the functional groups. The pyrolysis residues form a flowable solid material and not a melt. It is thus easy to handle and can be compacted or cemented, depending on the requirements for interim and permanent storage. Any further constituents such as inorganic filter materials or even other organic materials do not interfere with the process, they are dried, calcined or also pyrolysed. (orig.)

Slametschka, Rainer; Braehler, Georg [NUKEM Technologies GmbH (Germany)

2012-11-01

156

Vacuum pyrolysis of automobile shredder residues  

Energy Technology Data Exchange (ETDEWEB)

A research program was undertaken to evaluate the overall performance of a vacuum pyrolysis process applied to the treatment of Automobile Shredder Residues (ASR). North American and European ASR samples were tested. Vacuum pyrolysis experiments were carried out in the temperature range of 496-536C and a total pressure of approx. 1-5 kPa. Pyrolysis product yields averaged 52.5 wt.% solid residue, 27.7 wt.% organic liquids, 13.3 wt.% pyrolytic water and 6.6 wt.% pyrolysis gas. Composition of ASR feedstocks and pyrolysis products has been thoroughly characterized. After pyrolysis, ASR volume and weight were reduced 5x and 1.8x, respectively. It was possible to readily recover 14 wt.% of useful metals remaining in the solid residues; the material left over can be safely landfilled. Pyrolytic gas and oil can be used as heating fuels. The heavy fraction of the oil (>400C) can be added to road bitumens in order to improve their performance. The total oil also represents a challenging matrix for various purposes. The vacuum pyrolysis technology can be seen as an alternative to landfill and incineration.

Roy, C.; Chaala, A. [Institut Pyrovac Inc., Parc technologique du Quebec metropolitain, 333, rue Franquet, Sainte-Foy, G1P 4C7 Quebec (Canada)

2001-05-01

157

Orientation-dependent low field magnetic anomalies and room-temperature spintronic material Mn doped ZnO films by aerosol spray pyrolysis  

Energy Technology Data Exchange (ETDEWEB)

Graphical abstract: Optical microscopy images of Mn doped ZnO films deposited for 20 min. Highlights: MnZnO films showing transparent spherical bubbles were synthesized by ASP. LFMA phenomenon was observed for these films. A relatively novel reversal magnetic feature to that of LFMA was observed. Ferromagnetic to paramagnetic transition due to Mn doping was observed. Angular dependence analysis showed evidence of magnetic anisotropy present. -- Abstract: High quality un-doped and Mn-doped ZnO films deposited by a simple aerosol spray pyrolysis technique for 20 and 30 min were studied using electron paramagnetic resonance (EPR), X-ray diffraction (XRD) and atomic force microscopy (AFM) techniques. EPR analysis showed novel observation of low field microwave absorption (LFMA) on the manganese (Mn) doped zinc oxide (ZnO) films at various Mn concentrations. The results showed a peculiar behavior, reversal signal to that of LFMA. These findings also demonstrated that these films contain ferromagnetism at room temperature with possible applications in spintronics. Angular dependence measurements were found to induce magnetic transition from ferromagnetism to paramagnetism. Structural analysis showed that the undertaken materials are in wurtzite structures. The light absorption edge of MnZnO films red shifted which enhanced the observed ferromagnetism. The direct modulation of the band gap caused by MnZnO substitution is responsible for the red shift effect in absorption edge of ZnO.

Nkosi, S.S. [CSIR-National Laser Centre, 626 Meiring Naude Rd, Brummeria, Pretoria 0001 (South Africa); School of Physics, University of Witwatersrand, Private Bag X3, Johannesburg 2030 (South Africa); Kortidis, I. [Institute of Electronic Structure and Laser, Foundation for Research and Technology, Hellas, P.O. Box 1527, 71110 Heraklion, Crete (Greece); Motaung, D.E., E-mail: dmotaung@csir.co.za [DST/CSIR Nanotechnology Innovation Centre, National Centre for Nano-Structured Materials, Council for Scientific and Industrial Research, P.O. Box 395, Pretoria 0001 (South Africa); Malgas, G.F. [DST/CSIR Nanotechnology Innovation Centre, National Centre for Nano-Structured Materials, Council for Scientific and Industrial Research, P.O. Box 395, Pretoria 0001 (South Africa); Department of Physics, University of the Western Cape, Private Bag X17, Bellville, 7535 (South Africa); Keartland, J.; Sideras-Haddad, E. [School of Physics, University of Witwatersrand, Private Bag X3, Johannesburg 2030 (South Africa); Forbes, A. [CSIR-National Laser Centre, 626 Meiring Naude Rd, Brummeria, Pretoria 0001 (South Africa); School of Physics, University of Witwatersrand, Private Bag X3, Johannesburg 2030 (South Africa); Mwakikunga, B.W., E-mail: bmwakikunga@csir.co.za [DST/CSIR Nanotechnology Innovation Centre, National Centre for Nano-Structured Materials, Council for Scientific and Industrial Research, P.O. Box 395, Pretoria 0001 (South Africa); Sinha-Ray, S. [DST/CSIR Nanotechnology Innovation Centre, National Centre for Nano-Structured Materials, Council for Scientific and Industrial Research, P.O. Box 395, Pretoria 0001 (South Africa); Kiriakidis, G. [Institute of Electronic Structure and Laser, Foundation for Research and Technology, Hellas, P.O. Box 1527, 71110 Heraklion, Crete (Greece)

2013-12-05

158

Orientation-dependent low field magnetic anomalies and room-temperature spintronic material Mn doped ZnO films by aerosol spray pyrolysis  

International Nuclear Information System (INIS)

Graphical abstract: Optical microscopy images of Mn doped ZnO films deposited for 20 min. Highlights: MnZnO films showing transparent spherical bubbles were synthesized by ASP. LFMA phenomenon was observed for these films. A relatively novel reversal magnetic feature to that of LFMA was observed. Ferromagnetic to paramagnetic transition due to Mn doping was observed. Angular dependence analysis showed evidence of magnetic anisotropy present. -- Abstract: High quality un-doped and Mn-doped ZnO films deposited by a simple aerosol spray pyrolysis technique for 20 and 30 min were studied using electron paramagnetic resonance (EPR), X-ray diffraction (XRD) and atomic force microscopy (AFM) techniques. EPR analysis showed novel observation of low field microwave absorption (LFMA) on the manganese (Mn) doped zinc oxide (ZnO) films at various Mn concentrations. The results showed a peculiar behavior, reversal signal to that of LFMA. These findings also demonstrated that these films contain ferromagnetism at room temperature with possible applications in spintronics. Angular dependence measurements were found to induce magnetic transition from ferromagnetism to paramagnetism. Structural analysis showed that the undertaken materials are in wurtzite structures. The light absorption edge of MnZnO films red shifted which enhanced the observed ferromagnetism. The direct modulation of the band gap caused by MnZnO substitution is responsible for the red shift effect in absorption edge of ZnO

2013-12-05

159

An investigation on substrate temperature and copper to sulphur molar ratios on optical and electrical properties of nanostructural CuS thin films prepared by spray pyrolysis method  

Energy Technology Data Exchange (ETDEWEB)

Copper sulphide (CuS) thin films have been deposited on glass substrates by spray pyrolysis method using an aqueous solutions of copper (II) acetate and thiourea with different Cu to S molar ratios (0.33 and 0.43) at various substrate temperatures of 260, 285 and 310 Degree-Sign C. The structural, optical and electrical characterizations have been carried out using XRD, UV-Vis. transmittance/reflectance, PL spectra and Hall effect measurements. These characterizations indicated the formation of a CuS single phase (covellite) with polycrystalline nature with preferred orientation along (1 0 2) plane, except one with amorphous nature. Optical studies showed that the deposited layers have a relatively high absorption coefficient (5 Multiplication-Sign 10{sup 4} to 1 Multiplication-Sign 10{sup 5} cm{sup -1}) in the visible range, with an effective optical band gap of {approx}2.4-2.6 eV. The Hall effect data showed that all the grown samples have a degenerate p-type conductivity with a hole concentration of {approx}1.8 Multiplication-Sign 10{sup 20} to 1.7 Multiplication-Sign 10{sup 21} cm{sup -3}.

Adelifard, Mehdi [Department of Physics, Shahrood University of Technology, Shahrood 316-36155 (Iran, Islamic Republic of); Eshghi, Hosein, E-mail: h_eshghi@shahroodut.ac.ir [Department of Physics, Shahrood University of Technology, Shahrood 316-36155 (Iran, Islamic Republic of); Mohagheghi, Mohamad Mehdi Bagheri [School of Physics, Damghan University, Damghan (Iran, Islamic Republic of)

2012-05-15

160

Strong room-temperature ultraviolet emission from nanocrystalline ZnO and ZnO:Ag films grown by ultrasonic spray pyrolysis  

International Nuclear Information System (INIS)

Nanocrystalline ZnO and ZnO:Ag films have been deposited on Si (1 0 0) substrates by ultrasonic spray pyrolysis (USP) technique under ambient atmosphere. Among pure ZnO films, the sample deposited at 500 oC with spray rate of 0.15 ml/min has the strongest near-band edge (NBE) ultraviolet emission (378 nm) observed in the room-temperature photoluminescence (RT PL) measurement. Its PL intensity ratio (R) of the UV emission to the deep-level emission has a largest value of 470 and the full-width at half-maximum (FWHM) of UV peak has a smallest value of 10 nm (87 meV). Moreover, RT PL spectra show that compared with undoped ZnO, the UV emission intensity of ZnO:Ag films (with the Ag:Zn atomic ratio = 3% in the precursor solution) is even markedly enhanced and the R increases to the value of at least 700. However, a silver phase is detected and the UV luminescence becomes weak for ZnO:Ag films after the annealing at 700 oC in air for 1 h.

2008-12-30

 
 
 
 
161

Fast Pyrolysis of Lignin Using a Pyrolysis Centrifuge Reactor  

DEFF Research Database (Denmark)

Fast pyrolysis of lignin from an ethanol plant was investigated on a lab scale pyrolysis centrifuge reactor (PCR) with respect to pyrolysis temperature, reactor gas residence time, and feed rate. A maximal organic oil yield of 34 wt % dry basis (db) (bio-oil yield of 43 wt % db) is obtained at temperatures of 500??550 °C, reactor gas residence time of 0.8 s, and feed rate of 5.6 g/min. Gas chromatography mass spectrometry and size-exclusion chromatography were used to characterize the Chemical properties of the lignin oils. Acetic acid, levoglucosan, guaiacol, syringols, and p-vinylguaiacol are found to be major chemical components in the lignin oil. The maximal yields of 0.62, 0.67, and 0.38 wt % db were obtained for syringol, p-vinylguaiacol, and guaiacol, respectively. The reactor temperature effect was investigated in a range of 450??600 °C and has a considerable effect on the observed chemical components and molecular mass distribution of the lignin oils. The obtained lignin oil has a very different components composition when compared to a beech wood oil.

Trinh, Ngoc Trung; Jensen, Peter Arendt

2013-01-01

162

Zirconia coatings by spray pyrolysis  

Energy Technology Data Exchange (ETDEWEB)

Zirconia coatings were obtained with the spray pyrolysis process, using a precursor solution of zirconium n-propoxide in 1-propanol. An investigation was undertaken into the influence of carrier gas (air, He, N{sub 2} and Ar), temperature (450 and 600 C), time (1 and 2 h) and substrate composition (borosilicate glass, alumina, stainless steel and carbon steel) on coating characteristics. The most important deposition parameters were found to be the atomic or molecular weight of the carrier gas and the pyrolysis temperature. Cubic ZrO{sub 2} thin films, with dense and homogeneous nanostructure were obtained using He and N{sub 2} as carrier gas, at 600 C, on ceramic substrates. (orig.)

Ruiz, H. [Universidad Simon Bolivar, Caracas (Venezuela). Dept. Ciencia de los Materiales; Vesteghem, H. [CNRS, 87 - Limoges (France). Lab. Materiaux Ceramiques et Traitements de Surface; Di Giampaolo, A.R. [Universidad Simon Bolivar, Caracas (Venezuela). Dept. Ciencia de los Materiales; Lira, J. [Universidad Simon Bolivar, Caracas (Venezuela). Dept. Ciencia de los Materiales

1997-02-15

163

PYROLYSIS OF TOBACCO RESIDUE. PART 2: CATALYTIC  

Directory of Open Access Journals (Sweden)

Full Text Available The pyrolysis of tobacco residue in the presence of metal oxides and metal chlorides was investigated at 300, 400, and 500 C. Catalysts used were Al2O3, Fe2O3, AlCl3, and SnCl4 in concentrations from 1 up to 5 wt% of the tobacco residue feedstock. The amount of catalysts and the pyrolysis temperature had significant effect on both product distributions and bio-oil composition. The catalytic effect was dominant at the lowest temperature (300 C. The pyrolysis temperature was decreased by 200 C compared to the thermal run. Bio-oil contained a large variety of compounds. Nicotine, which is very stable until temperatures in excess of 600 C, could be degraded at the lowest temperature by using 1 wt% of AlCl3 and 1 wt% of Fe2O3.

Mehmet K. Akalin

2011-04-01

164

SIMULATION OF OLIVE PITS PYROLYSIS IN A ROTARY KILN PLANT  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This work deals with the simulation of an olive pits fed rotary kiln pyrolysis plant installed in Southern Italy. The pyrolysis process was simulated by commercial software CHEMCAD. The main component of the plant, the pyrolyzer, was modelled by a Plug Flow Reactor in accordance to the kinetic laws. Products distribution and the temperature profile was calculated along reactor's axis. Simulation results have been found to fit well the experimental data of pyrolysis. Moreover, sensitivity anal...

Enzo Benanti; Cesare Freda; Vincenzo Lorefice; Giacobbe Braccio; Vinod Kumar Sharma

2011-01-01

165

Pyrolysis and Oxidation of PAN in Dry Air. Thermoanalytical Methods  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The results of investigations on pyrolysis and oxidation of pure polyacrylonitrile (PAN) and its mixture with N,N-dimethylformamide (DMF) under non-isothermal conditions at linear change of samples temperature in time are presented. In each case process proceeded in different way. During pyrolysis of pure PAN the material containing mainly the product after PAN cyclization was obtained, while pyrolysis of PAN+DMF mixture gave the product after cyclization and stabilization. Under conditi...

Biedunkiewicz, Anna; Figiel, Pawel; Sabara, Marta

2011-01-01

166

Kinetics of biomass pyrolysis  

Energy Technology Data Exchange (ETDEWEB)

The project Kinetics of Biomass Pyrolysis of the Department of Energy and Process Engineering at Tampere University of Technology (TUT) is focused on the modelling of the chemical kinetics and heat transfer effects of wood pyrolysis. The project focused especially on the effect of the internal heat transfer rate of the fuel particles and on the chemical reaction kinetics of the pyrolysis reactions. The project aimed to form a one dimensional mathematical simulation tool.

Kokko, L. [Tampere Univ. of Technology,Dept. of Energy and Process Engineering (Finland)], email: lauri.kokko@tut.fi

2012-07-01

167

Pyrolysis and Gasification  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Pyrolysis and gasification include processes that thermally convert carbonaceous materials into products such as gas, char, coke, ash, and tar. Overall, pyrolysis generates products like gas, tar, and char, while gasification converts the carboncontaining materials (e.g. the outputs from pyrolysis) into a mainly gaseous output. The specific output composition and relative amounts of the outputs greatly depend on the input fuel and the overall process configuration. Although pyroly...

Astrup, Thomas; Bilitewski, B.

2010-01-01

168

Decomposition of ion exchange resins by pyrolysis  

International Nuclear Information System (INIS)

Pyrolysis of spent ion exchange resins is one of the most effective methods for reducing radioactive waster volume and for making the final waste form more stable. Fundamental experiments were performed to clarify the pyrolysis characteristics of anion and cation exchange resins. Residual elemental analyses and off-gas analyses showed that the decomposition ratio of cation resins was only 50 wt% at 600"0C, while that of anion resins was 90 wt% at 400"0C. Infrared spectroscopy for cation resins attributed its low decomposition ratio to formation of a highly heat-resistant polymer (sulfur bridged) during pyrolysis. Measurements of residual hygroscopicity and cement package strength indicated that the optimum pyrolysis temperatures for preventing resins swelling and package expansion were between 300 and 500"0C

1986-01-01

169

Samarium diiodide-mediated deoxygenation of taxol: A one-step synthesis of 10-deacetoxytaxol  

Energy Technology Data Exchange (ETDEWEB)

Taxol (1) has been approved by the FDA for the treatment ovarian cancer. The authors here present a single-step synthesis of 10-deacetoxytaxol via a SmI{sub 2}-mediated deoxygenation of taxol (1). 10-deacetoxytaxol has similar biological activity to that of taxol. 1 fig., 1 tab.

Georg, G.I.; Cheruvallath, Z.S. [Univ. of Kansas, Lawrence, KS (United States)

1994-07-15

170

PROPERTIES OF GAS AND CHAR FROM MICROWAVE PYROLYSIS OF PINE SAWDUST  

Directory of Open Access Journals (Sweden)

Full Text Available Pine sawdust pyrolysis was carried out respectively using microwave and conventional electrical heating at different temperatures in order to understand the properties of pyrolytic products from microwave pyrolysis of biomass. Less char material was obtained by microwave pyrolysis compared to conventional heating at the same temperature. While comparing the components of the pyrolytic gases, it was revealed that the microwave pyrolysis gas usually had higher H2 and CO contents and lower CH4 and CO2 contents than those obtained by conventional pyrolysis at the same temperature. The texture analysis results of the microwave pyrolysis chars showed that the chars would melt and the pores would shrink at high temperatures, and hence, the specific surface areas of the chars decreased with increasing temperature. Similarly, the reactivity of the char was remarkably reduced when the microwave pyrolysis temperature exceeded 600C.

Xian-Hua Wang

2009-08-01

171

CATALYTIC FAST PYROLYSIS OF CELLULOSE MIXED WITH SULFATED TITANIA TO PRODUCE LEVOGLUCOSENONE: ANALYTICAL PY-GC/MS STUDY  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Sulfated titania (SO42-/TiO2) was prepared and used for catalytic fast pyrolysis of cellulose to produce levoglucosenone (LGO), a valuable anhydrosugar product. Analytical pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) technique was employed in this study to achieve the catalytic fast pyrolysis of cellulose and on-line analysis of the pyrolysis vapors. Experiments were performed to investigate the effects of several factors on the LGO production, i.e. pyrolysis temperature, cellulo...

2012-01-01

172

Molecular products and radicals from pyrolysis of lignin.  

Science.gov (United States)

Thermal degradation of lignin under two reaction regimes (pyrolysis in N(2) and oxidative pyrolysis in 4% O(2) in N(2)) has been investigated in a tubular, isothermal, flow-reactor over the temperature range 200-900 C at a residence time of 0.2 s. Two experimental protocols were adopted: (1) Partial pyrolysis in which the same lignin sample was continuously pyrolyzed at each temperature and (2) conventional pyrolysis, in which new lignin samples were pyrolyzed at each pyrolysis temperature. The results identified common relationships between the two modes of experiments, as well as some differences. The majority of products from partial pyrolysis peaked between 300 and 500 C, whereas for conventional pyrolysis reaction products peaked between 400 and 500 C. The principal products were syringol (2,6-dimethoxy phenol), guaiacol (2-methoxy phenol), phenol, and catechol. Of the classes of compounds analyzed, the phenolic compounds were the most abundant, contributing over 40% of the total compounds detected. Benzene, styrene, and p-xylene were formed in significant amounts throughout the entire temperature range. Interestingly, six ringed polycyclic aromatic hydrocarbons were formed during partial pyrolysis. Oxidative pyrolysis did not result in large differences from pyrolysis; the main products still were syringol, guaiacol, phenol, the only significant difference being the product distribution peaked between 200 and 400 C. For the first time, low temperature matrix isolation electron paramagnetic resonance was successfully interfaced with the pyrolysis reactor to elucidate the structures of the labile reaction intermediates. The EPR results suggested the presence of methoxyl, phenoxy, and substituted phenoxy radicals as precursors for formation of major products; syringol, guaiacol, phenols, and substituted phenols. PMID:23131040

Kibet, J; Khachatryan, L; Dellinger, B

2012-12-01

173

The pyrolysis of peat. A comprehensive review of the literature  

Energy Technology Data Exchange (ETDEWEB)

An ample discussion on peat pyrolysis is presented. Main products are: (semi)coke, activated carbon, peat tar, and combustible gases. The term peat tar is used to refer to the total pyrolysis condensate and contains a very wide range of water soluble and insoluble organic compounds. The role of process parameters such as pressure and temperature is dealt with; the combined pyrolysis of peat with other products such as water, petroleum residues, methane, etc., is also discussed. Applications of the main products are surveyed. Finally the industrial pyrolysis process is described in detail. 249 Literature references are given. (A.V.)

Roy, C. (Sherbrooke Univ., Quebec (Canada)); Chornet, E.; Fuchsman, C.H.

1983-12-01

174

TBP/kerosene pyrolysis and combustion at pilot scale  

International Nuclear Information System (INIS)

Pyrolysis and combustion technology is an available method to treat spent organic solvent--intermediate level radioactive TBP-kerosene. The pilot system with the treatment capacity of 25 kgh-1 is designed and installed. Influences of technical parameters such as pyrolysis temperature, feeding rate, feed composition, etc, on pyrolysis rate and fixation rate of phosphorus indicate that pyrolysis rate of TBP and fixation rate of phosphorus are more than 99.5% at given condition, the decontamination factors (DF) of U, Sr and Cs in the whole system are more than 106

1999-11-01

175

SIMULATION OF OLIVE PITS PYROLYSIS IN A ROTARY KILN PLANT  

Directory of Open Access Journals (Sweden)

Full Text Available This work deals with the simulation of an olive pits fed rotary kiln pyrolysis plant installed in Southern Italy. The pyrolysis process was simulated by commercial software CHEMCAD. The main component of the plant, the pyrolyzer, was modelled by a Plug Flow Reactor in accordance to the kinetic laws. Products distribution and the temperature profile was calculated along reactor's axis. Simulation results have been found to fit well the experimental data of pyrolysis. Moreover, sensitivity analyses were executed to investigate the effect of biomass moisture on the pyrolysis process.

Giacobbe Braccio

2011-01-01

176

FAST PYROLYSIS OF ENZYMATIC/MILD ACIDOLYSIS LIGNIN FROM MOSO BAMBOO  

Directory of Open Access Journals (Sweden)

Full Text Available The characteristics of enzymatic/mild acidolysis lignin (EMAL isolated from moso bamboo were investigated using pyrolysis-gas chromato-graphy/mass spectrometry (Py-GC/MS. Pyrolysis temperature as a factor on products was studied, and the pyrolysis mechanism was inferred with respect to the dominating products. Research results showed that pyrolysis products derived from EMAL pyrolysis were mainly heterocyclic (2,3-dihydrobenzofuran, phenols, esters, and a minor amount of acetic acid. Pyrolysis temperature had a distinct impact on yields of pyrolysis products. As pyrolysis temperature increased, the yield of 2,3-dihydrobenzofuran rapidly decreased; however, yields of phenols increased smoothly. It can be obtained that, at the low temperatures (250-400oC, pyrolysis products were mainly 2,3-dihydrobenzofuran, and the highest yield was 66.26% at 320oC; at the high temperatures (400-800oC, pyrolysis products were mainly phenols, and yields hit their highest level of 56.43% at 600 oC. A minor amount of acetic acid only emerged at 800C. Knowledge of pyrolysis products releasing from EMAL and the pyrolysis mechanism could be basic and essential to the understanding of thermochemical conversion of EMAL to chemicals or high-grade energy.

Rui Lou

2010-05-01

177

Analyses of residual iron in carbon nanotubes produced by camphor/ferrocene pyrolysis and purified by high temperature annealing  

International Nuclear Information System (INIS)

A detailed analysis of iron-containing phases in multiwall carbon nanotube (MWCNT) powder was carried out. The MWCNTs were produced by camphor/ferrocene and purified by high temperature annealing in an oxygen-free atmosphere (N2 or VC). Thermogravimetric analysis, Moessbauer spectroscopy, X-ray diffraction and X-ray photoelectron spectroscopy enabled the evaluation of the residual iron in MWCNTs after purification. The VC treatments provided MWCNTs with a purity degree higher than 99%. Moreover, Raman spectroscopy revealed a significant improvement in graphitic ordering after thermal annealing. A brief description of the mechanism of iron removal was included. We highlight the mobility of iron atoms through graphitic sheets and the large contact angle of iron clusters formed on MWCNT surfaces at high temperatures.

2011-07-01

178

Analyses of residual iron in carbon nanotubes produced by camphor/ferrocene pyrolysis and purified by high temperature annealing  

Energy Technology Data Exchange (ETDEWEB)

A detailed analysis of iron-containing phases in multiwall carbon nanotube (MWCNT) powder was carried out. The MWCNTs were produced by camphor/ferrocene and purified by high temperature annealing in an oxygen-free atmosphere (N{sub 2} or VC). Thermogravimetric analysis, Moessbauer spectroscopy, X-ray diffraction and X-ray photoelectron spectroscopy enabled the evaluation of the residual iron in MWCNTs after purification. The VC treatments provided MWCNTs with a purity degree higher than 99%. Moreover, Raman spectroscopy revealed a significant improvement in graphitic ordering after thermal annealing. A brief description of the mechanism of iron removal was included. We highlight the mobility of iron atoms through graphitic sheets and the large contact angle of iron clusters formed on MWCNT surfaces at high temperatures.

Antunes, E.F., E-mail: ericafa@las.inpe.br [Instituto Tecnologico de Aeronautica (ITA), Praca Marechal Eduardo Gomes, 50, CEP 12.228-900, Sao Jose dos Campos, SP (Brazil); Instituto Nacional de Pesquisas Espaciais (INPE), Av. dos Astronautas, 1758, CEP 12.227-010, Sao Jose dos Campos, SP (Brazil); Resende, V.G. de; Mengui, U.A. [Instituto Nacional de Pesquisas Espaciais (INPE), Av. dos Astronautas, 1758, CEP 12.227-010, Sao Jose dos Campos, SP (Brazil); Cunha, J.B.M. [Universidade Federal do Rio Grande do Sul (UFRGS), Av. Bento Goncalves, 9500, CEP 91.501-970, Porto Alegre, RS (Brazil); Corat, E.J.; Massi, M. [Instituto Nacional de Pesquisas Espaciais (INPE), Av. dos Astronautas, 1758, CEP 12.227-010, Sao Jose dos Campos, SP (Brazil)

2011-07-01

179

FAST PYROLYSIS OF LIGNINS  

Directory of Open Access Journals (Sweden)

Full Text Available Three lignins: Indulin AT, LignoboostTM, and Acetocell lignin, were characterized and pyrolyzed in a continuous-fed fast pyrolysis process. The physical and chemical properties of the lignins included chemical composition, heat content, ash, and water content. The distributed activation energy model (DAEM was used to describe the pyrolysis of each lignin. Activation energy distributions of each lignin were quite different and generally covered a broad range of energies, typically found in lignins. Process yields for initial continuous-fed fast pyrolysis experiments are reported. Bio-oil yield was low, ranging from 16 to 22%. Under the fast pyrolysis conditions used, the Indulin AT and LignoboostTM lignin yielded slightly more liquid product than the Acetocell lignin. Lignin kinetic parameters and chemical composition vary considerably and fast pyrolysis processes must be specified for each type of lignin.

Sedat Beis

2010-05-01

180

Pyrolysis system evaluation study  

Science.gov (United States)

An evaluation of two different pyrolysis concepts which recover energy from solid waste was conducted in order to determine the merits of each concept for integration into a Integrated Utility System (IUS). The two concepts evaluated were a Lead Bath Furnace Pyrolysis System and a Slagging Vertical Shaft, Partial Air Oxidation Pyrolysis System. Both concepts will produce a fuel gas from the IUS waste and sewage sludge which can be used to offset primary fuel consumption in addition to the sanitary disposal of the waste. The study evaluated the thermal integration of each concept as well as the economic impact on the IUS resulting from integrating each pyrolysis concepts. For reference, the pyrolysis concepts were also compared to incineration which was considered the baseline IUS solid waste disposal system.

1974-01-01

 
 
 
 
181

Hydrothermal deoxygenation of triglycerides over Pd/C aided by in situ hydrogen production from glycerol reforming.  

Science.gov (United States)

A one-pot catalytic hydrolysis-deoxygenation reaction for the conversion of unsaturated triglycerides and free fatty acids to linear paraffins and olefins is reported. The hydrothermal deoxygenation reactions are performed in hot compressed water at 250 C over a Pd/C catalyst in the absence of external H2 . We show that aqueous-phase reforming (APR) of glycerol and subsequent water-gas-shift reaction result in the in situ formation of H2 . While this has a significant positive effect on the deoxygenation activity, the product selectivity towards high-value, long-chain olefins remains high. PMID:24596129

Hollak, Stefan A W; Arins, Maxim A; de Jong, Krijn P; van Es, Daan S

2014-04-01

182

Kinetics of biomass pyrolysis  

Energy Technology Data Exchange (ETDEWEB)

The project 'Kinetics of Biomass Pyrolysis' of the Department of Energy and Process Engineering at Tampere University of Technology (TUT) is focused on the modelling of the chemical kinetics and heat transfer effects of wood pyrolysis. Pyrolysis is one of the stages of combustion but it can also be conducted as a separate process to produce pyrolysis oil (bio-oil). This project focuses especially on the effect of the internal heat transfer rate of the fuel particles and on the chemical reaction kinetics of the pyrolysis reactions. The work is linked to the project 'Integrated utilization chains of second-generation pyrolysis' of the VTT Technical Research Centre of Finland. A mathematical model for the heat transfer effects and the chemical kinetics of wood pyrolysis has been developed. The model will be finished with a user-friendly graphical user interface by the end of 2010. Model verification and validation has been done with the results from the experiments made in a specially built reactor in the TUT laboratory. Validation of the model will be completed by comparing the model and the results from additional experimental measurements by the end of 2010. The specific heats of wood and char have also been studied using a differential scanning calorimeter. The project started in 2008 for a period of three years. The main interest in 2008 was heat transfer studies of wood and its char. The focus in 2009 was on the specific heat capacity of wood, on the chemical kinetics of pyrolysis, and on the high-heating-rate pyrolysis experiments. A draft version of the pyrolysis model was written in 2009 and the model will be validated and completed by the end of 2010. (orig.)

Kokko, L.; Tolvanen, H.; Hankalin, V.; Raiko, R. (Tampere Univ. of Technology (Finland). Dept. of Energy and Process Engineering), Email: lauri.kokko@tut.fi

2010-10-15

183

Thermogravimetric Analysis and Global Kinetics of Segregated MSW Pyrolysis  

Directory of Open Access Journals (Sweden)

Full Text Available Municipal Solid Wastes (MSW has great potential as a clean, renewable feedstock for producing modern energy carriers through thermochemical, called pyrolysis. However, despite their enormous potential as energy sources, their thermal characteristics are still not well known. Investigations about segregated MSW slow pyrolysis behaviors have done using macro balance apparatus. Four components of segregated MSW (bamboo wastes, banana leaves wastes, snack wrap wastes and styrofoam wastes and their bleds were thermally degraded through thermogravimetry analysis and their characteristics such as pyrolysis profiles and activation energies were analysed and calculated. About 20 grams of samples pyrolysed under 100 ml/min N2 at constant heating rate 10 0C/min from room temperature to 400 0C final pyrolysis temperature which kept constant for 30 minutes. The nitrogen flow as swept gas which ensures an inert atmosphere during the pyrolysis test.In order to indenty the pyrolysis characteristics of samples, thermogravimetry analysis performed. The recorded data were weight losses and sample temperature during the pyrolisis process. The results of the research showed bamboo wastes and banana leaves wastes could be catogorized as low stability organics, while snack wrap wastes could be catagorized as polymer mixture materials and styrofoam wastes could be catagorized as plastic materials.Meanwhile the blends materials pyrolysis profiles followed the their components characteristics which signed with the peak temperature which occured. This study also found that global kinetic method could to calculate the pyrolysis activation energy

Dwi Aries Himawanto

2011-12-01

184

Synthesis and characterizations of composite particles for solid oxide fuel cell anodes by spray pyrolysis and intermediate temperature cell performance  

Science.gov (United States)

NiO-Ce 0.8Sm 0.2O 1.9 (SDC) composite particles were synthesized using starting solutions containing the components for NiO-SDC and various amounts of nitric acid. It was found that the particles had a different surface morphology and specific surface area depending on the pH values of the starting solutions. SOFC single cell using the composite particles as an anode electrode was examined at an intermediate temperature to clarify the relationship between particle morphology and cell performance. High and consistent cell performance was obtained when the composite particles were synthesized using the solutions containing large amounts of nitric acid. It was considered that the morphology and the specific surface area of NiO-SDC composite particles played an important role realizing a high cell performance anode.

Kawano, Mitsunobu; Hashino, Koji; Yoshida, Hiroyuki; Ijichi, Hiroshi; Takahashi, Seiji; Suda, Seiichi; Inagaki, Toru

185

Gas chromatography mass spectrometric quantitative determination of product distribution of paper pyrolysis with solid acids at low temperature  

International Nuclear Information System (INIS)

Paper was pyrolyzed at low temperature (300 degree C) both in the absence and presence of catalysts. The liquid products were collected and characterized by using GC/MS. Boric acid and aluminum sulphate acting as catalysts were found to alter the relative concentration and nature of the product due to depolymerizing, polarizing and free radical stabilizing properties. Boric acid was found to decrease the amount of anhydro sugars and favors the formation of esters, ketones and carboxylic acids. Aluminum sulphate favored the formation of furan carboxaldehyde, phenols and other cyclic compounds The cracking of paper and formation of new compounds was facilitated by vacant orbital of the catalyst. Therefore change in concentration of catalyst also changed the nature and concentration of the products. These observations are explained on the basis of the chemical nature of these compounds in this paper. (author)

2009-12-01

186

Pyrolysis of cellulose and lignin  

International Nuclear Information System (INIS)

X-ray and UV-induced photoelectron spectroscopy (XPS and UPS) and scanning electron microscopy (SEM) have been performed to characterise the pyrolysis of cellulose and lignin and their interaction with methanol. Clean highly oriented pyrolitic graphite (HOPG) was also analysed as a reference material. Asymmetric C1s core level fits and valence band XPS of the samples indicate a graphitic-like structure after the pyrolysis at 1200 deg. C. Due to the low polar contents in pyrolysed cellulose and lignin, an interaction with methanol under high vacuum conditions could not be identified. From a technical viewpoint a temperature of 1200 deg. C is attainable without high costs. Therefore, the pyrolysis of wood-based polymers containing high amounts of cellulose and lignin are potential low-cost materials for various applications. If it is possible to generate graphite in complex structures made of wood-based polymers, a cheap and energy-efficient method will become available for producing bipolar plates for fuel cells. Technical problems like form instability and foaming are discussed as well as further development and possible modifications of the ground material to achieve optimal compositions.

2009-06-30

187

The use of waste matter after olive grove pruning for the preparation of charcoal. The influence of the type of matter, particle size and pyrolysis temperature  

Energy Technology Data Exchange (ETDEWEB)

Charcoal was obtained from waste matter after olive grove pruning: leaves, branch bark, twig and wood (sawdust and cubes of different sizes). The charcoals were prepared by pyrolysis under dynamic heating conditions in nitrogen (dynamic, 200ml/min) and air (static) and were characterized by proximate and elemental analysis, helium density and BET surface area. (author).

Valenzuela Calahorro, C.; Gomez Serrano, V.; Bernalte Garcia, A. (Univ. de Extremadura, Badajoz (ES). Dept. de Quimica Inorganica); Hernandez Alvaro, J. (Colegio Univ., Jaen (ES))

1992-01-01

188

Gold Nanoparticle-Catalyzed Environmentally Benign Deoxygenation of Epoxides to Alkenes  

Directory of Open Access Journals (Sweden)

Full Text Available We have developed a highly efficient and green catalytic deoxygenation of epoxides to alkenes using gold nanoparticles (NPs supported on hydrotalcite [HT: Mg6Al2CO3(OH16] (Au/HT with alcohols, CO/H2O or H2 as the reducing reagent. Various epoxides were selectively converted to the corresponding alkenes. Among the novel metal NPs on HT, Au/HT was found to exhibit outstanding catalytic activity for the deoxygenation reaction. Moreover, Au/HT can be separated from the reaction mixture and reused with retention of its catalytic activity and selectivity. The high catalytic performance of Au/HT was attributed to the selective formation of Au-hydride species by the cooperative effect between Au NPs and HT.

Kiyotomi Kaneda

2011-09-01

189

Microwave induced pyrolysis of oil palm biomass.  

Science.gov (United States)

The purpose of this paper was to carry out microwave induced pyrolysis of oil palm biomass (shell and fibers) with the help of char as microwave absorber (MA). Rapid heating and yield of microwave pyrolysis products such as bio-oil, char, and gas was found to depend on the ratio of biomass to microwave absorber. Temperature profiles revealed the heating characteristics of the biomass materials which can rapidly heat-up to high temperature within seconds in presence of MA. Some characterization of pyrolysis products was also presented. The advantage of this technique includes substantial reduction in consumption of energy, time and cost in order to produce bio-oil from biomass materials. Large biomass particle size can be used directly in microwave heating, thus saving grinding as well as moisture removal cost. A synergistic effect was found in using MA with oil palm biomass. PMID:20970995

Salema, Arshad Adam; Ani, Farid Nasir

2011-02-01

190

The relationship between muscle deoxygenation and activation in different muscles of the quadriceps during cycle ramp exercise  

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The relationship between muscle deoxygenation and activation was examined in three different muscles of the quadriceps during cycling ramp exercise. Seven young male adults (24 3 yr; mean SD) pedaled at 60 rpm to exhaustion, with a work rate (WR) increase of 20 W/min. Pulmonary oxygen uptake was measured breath-by-breath, while muscle deoxygenation (HHb) and activity were measured by time-resolved near-infrared spectroscopy (NIRS) and surface electromyography (EMG), respectively, at the...

Chin, Lisa M. K.; Kowalchuk, John M.; Barstow, Thomas J.; Kondo, Narihiko; Amano, Tatsuro; Shiojiri, Tomoyuki; Koga, Shunsaku

2011-01-01

191

An Ill-posed Parabolic Evolution System for Dispersive Deoxygenation-Reaeration in Waters  

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We consider an inverse problem that arises in the management of water resources and pertains to the analysis of the surface waters pollution by organic matter. Most of physical models used by engineers derive from various additions and corrections to enhance the earlier deoxygenation-reaeration model proposed by Streeter and Phelps in 1925, the unknowns being the biochemical oxygen demand (BOD) and the dissolved oxygen (DO) concentrations. The one we deal with includes Taylor's dispersion to ...

Azai?ez, Mejdi; Ben Belgacem, Faker; Hecht, Fre?de?ric; Le Bot, Ce?dric

2013-01-01

192

A new approach for reduction of methylene green withascorbic acid by de-oxygenation through carbondioxide  

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Reduction kinetics of the methylene green (MG) with ascorbic acid (AA) in acidic medium at ?max 660 nm was monitored through visible spectrophotomtry in absence and presence of sodium carbonate. CO2 release through reaction of sodium carbonate and oxalic acid, created deoxygenated atmosphere for reduction of dye which greatly boosted the reaction rate. Initially slow reaction in presence of atmospheric oxygen proceeded rapidly when sodium carbona...

Rafia Azmat; Noshab Qamar; Raheela Naz

2011-01-01

193

Deoxygenative olefination reaction as the key step in the syntheses of deoxy and iminosugars.  

Science.gov (United States)

Just a spoonful of sugar! A new synthetic strategy involving the use of a deoxygenative olefination reaction as the key step was developed for the preparation of deoxy and iminosugars in their optically active form (see scheme). This strategy has been proven successful by the use of a pentose, hexose, heptose, and disaccharide as the starting materials. Furthermore, it was applied in a formal total synthesis of iminosugar (-)-1-deoxy-L-fuconojirimycin, which can inhibit ?-L-fucosidase. PMID:22615220

Chang Hsu, Yung; Hwu, Jih Ru

2012-06-18

194

Selecative deoxygenation of stearic acid via an anhydride pathway  

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Stearic anhydride is proposed as reactive intermediate in the hydrogen free decarbonylation and ketonization of stearic acid over Pd/Al2O3 at 523 K. This information is crucial towards developing of a selective low temperature decarbonylation process of fatty acids towards olefins.

Hollak, S. A. W.; Bitter, W.; Haveren, J.; Es, D. S.

2012-01-01

195

CATALYTIC THERMAL DECOMPOSITION OF POLYETHYLENE BY PYROLYSIS GAS CHROMATOGRAPHY  

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An experimental study of the thermal decomposition of polyethylene in an inert atmosphere has been carried out in the temperature range 300-800C using Shimadzu PYR-2A pyrolyzer for heating the sample. The method allows the accurate control and measurement of the pyrolysis temperature. The production of hydrocarbons and the corresponding monomers of these polymeric systems were monitored. The effects of variation of temperature, sample size, pyrolysis atmosphere, residence time and catalyst ...

JAN NISAR; MUKHTIAR ALI; IFTIKHAR AHMAD AWAN

2011-01-01

196

CHARACTERISTICS OF CORN STALK HEMICELLULOSE PYROLYSIS IN A TUBULAR REACTOR  

Directory of Open Access Journals (Sweden)

Full Text Available Pyrolysis characteristics of corn stalk hemicellulose were investigated in a tubular reactor at different temperatures, with focus mainly on the releasing profiles and forming behaviors of pyrolysis products (gas, char, and tar. The products obtained were further identified using various approaches (including GC, SEM, and GC-MS to understand the influence of temperature on product properties and compositions. It was found that the devolatilization of hemicellulose mainly occurred at low temperatures

Gao-Jin Lv

2010-08-01

197

Modification and implications of changes in electrochemical responses encountered when undertaking deoxygenation in ionic liquids.  

Science.gov (United States)

Physicochemical changes and substantially modified electrochemical behavior have been reported when ionic liquids are degassed with nitrogen. In conventional experiments in aqueous and organic media, degassing with N(2) is commonly used to remove the electroactive dissolved oxygen. However, in hydrophilic ionic liquid media, degassing with N(2) removes not only the dissolved oxygen but also a significant amount of the adventitious water present. Given the low viscosity of water, this in turn leads to a dramatic change of the viscosity of the degassed ionic liquid and hence mass transport properties that influence voltammetric responses. In the widely used and relatively viscous room temperature ionic liquid, 1-n-butyl-3-methylimidazolium tetrafluoroborate (BMIMBF(4)) containing the redox probe tetracyanoquinodimethane (TCNQ) and 9% (v/v) deliberately added water, 1 h degassing with very dry N(2) under benchtop conditions results in a dramatic decrease of the TCNQ reduction current obtained under steady-state conditions at a 1 mum diameter microdisc electrode. This is reflected by a change of diffusion coefficient of TCNQ (D(TCNQ)) from 2.6 x 10(-7) to 4.6 x 10(-8) cm(2) s(-1). Karl Fischer titration measurements show that almost complete removal of the deliberately added 9% water is achieved by degassing under benchtop conditions. However, displacement of oxygen by nitrogen in the ionic liquid solution results in the decrease of electrochemical reduction current by 6%, implying that dissolved gases need not be inert with respect to solvent properties. Oxygen removal by placing the BMIMBF(4) ionic liquid in a nitrogen-filled glovebox or in a vacuum cell also simultaneously leads to removal of water and alteration of voltammetric data. This study highlights that (i) important physicochemical differences may arise upon addition or removal of a solute from viscous ionic liquids; (ii) degassing with dry nitrogen removes water as well as oxygen from ionic liquids, which may have implications on the viscosity and structure of the medium; (iii) particular caution must be exercised when deoxygenation is applied in ionic liquid media as part of the protocol used in electrochemical experiments to remove oxygen; (iv) gases such as oxygen, argon, and nitrogen dissolved in ionic liquids need not be innocent with respect to the properties of an ionic liquid. The use of vacuum based techniques to eliminate all volatile solutes, including water and oxygen, is advocated. PMID:20392069

Zhao, Chuan; Bond, Alan M; Compton, Richard G; O'Mahony, Aoife M; Rogers, Emma I

2010-05-01

198

Phosphate ester cleavage in ribose-5-phosphate induced by OH radicals in deoxygenated aqueous solution  

International Nuclear Information System (INIS)

The reaction of OH radicals and H atoms with ribose-5-phosphate (10-2M) in deoxygenated aqueous solution at room temperature (dose-rate 2.1 x 1017 eV/ml . min, dose 5 x 1018 to 15 x 1018 eV/ml) led to the following dephosphorylation products (G-values): ribo-pentodialdose 1 (0.2), 2-hydroxy-4-oxo-glutaraldehyde 2 (0.06), 5-deoxy-erythro-pentos-4-ulose 3 (0.1) and 3-oxo-glutaraldehyde 4 (0.06). In addition, some minor phosphate free products (total G = 0.09) were formed. G(inorganic phosphate) = 1.3 and G(H2O2) = 0.3. On the addition of 10-3 M Fe(III) ions, G(1) and G(3) increased to 0.6 and 0.4, respectively. In the presence of 10-3M Fe(II), G(1) and G(3) changed to 0.4 amd 0.8, respectively. The other dephosphorylation products were suppressed by the iron ions. G(1) also increased on the addition of increasing amounts of H2O2. Each product could be assigned a precursor radical formed by hydrogen abstraction from C-5, C-4 or C-3 of the ribose-5-phosphate molecule. Products 1 and 2 were formed by oxydative dephosphorylation of an ?-phospho radical with preceding H2O elimination for product 2. Elimination of H3PO4 from a ?-phospho radical led to product 3; product 4 was formed by elimination of two molecules of H2O from its precursor radical and hydrolytic cleavage of an enol phosphate bond. Deuterium-labelling experiments and the effects of the iron ions and of H2O2 support the mechanisms proposed. The importance of the dephosphorylation mechanisms for the formation of strand breaks in DNA is discussed with special reference to the effects of the radiosensitizers. (author)

1976-01-01

199

Environmental fatigue behaviors of wrought and cast stainless steels in 310 .deg. C Deoxygenated Water  

International Nuclear Information System (INIS)

Environmental fatigue behaviors of wrought type 316LN stainless steel and cast CF8M stainless steel were investigated. LCF tests were performed at fixed strain rate of 0.04%/s with 0.4%, 0.6%, 0.8%, 1.0% strain amplitudes in 310 .deg. C deoxygenated water environment. In addition, to analyze microstructure effect on fatigue behavior, low cycle fatigue tests in air environment were performed at fixed strain rate of 0.4%/s, 0.04%/s with 0.4%, 0.8% strain amplitudes. It was shown that the low cycle fatigue life of CF8M in a 310 .deg. C deoxygenated water environment was slightly longer than that of 316LN. On the other hand, the low cycle fatigue life of CF8M in a 310 .deg. C air environment was slightly shorter than that of 316LN or was similar with that of 316LN. Through OM observation and phase image analysis, it was confirmed that the ferrite content of CF8M tested in a 310 .deg. C deoxygenated water environment was larger than that of CF8M tested in a 310 .deg. C air environment. It was shown that the ferrite phase fraction of CF8M tested in 310 .deg. C deoxygenated water environment was approximately 26?28% and that of CF8M tested in air environment was approximately 10?12%. The difference of ferrite content in CF8M results in superior tensile properties as higher ferrite content. Furthermore, the difference of ferrite content in CF8M might be the cause of different result of fatigue life between CF8M and 316LN depending on environment. In this study, focused on CF8M having 26?28% ferrite content, to understand the causes of these differences in a 310 .deg. C deoxygenated water environment, fracture surface and crack morphology were observed. And material factors like microstructure, mechanical properties factors like stress behavior during fatigue life, factors by environmentally assisted cracking (EAC) like hydrogen induced cracking (HIC) and chemical compositions of both materials were analyzed. Mainly in a 310 .deg. C deoxygenated water environment, the analysis of fatigue surface was conducted at 1.0% strain amplitude, the analysis of crack sectioned area was conducted at 0.8% strain amplitude. Mainly in air environment, the analysis of fatigue surface was conducted at 0.4% strain amplitude. Through this study and analysis, it was thought that low cycle fatigue crack growth rate of CF8M would be affected by relative contribution of both barrier role of ferrite phase and acceleration role of crack linkage phenomenon or HIC. In low cycle fatigue operating relatively higher stress, it was known that the crack generally tend to avoid and propagate around hard phase. Like the preceding, this test results indicated that the barrier role such as crack avoiding is slightly greater than acceleration role such as crack linkage added HIC mechanism, resulting in slower fatigue crack growth rate by consumption of excess energy, or longer LCF lives in cast CF8M than wrought type 316LN in 310 .deg. C deoxygenated water

2011-01-01

200

Effects of pyrolysis temperature, time and leaf litter and powder coal ash addition on sludge-derived adsorbents for nitrogen oxide.  

Science.gov (United States)

The objective of this research was to seek a cost effective solution to prepare adsorbents for nitrogen oxide from surplus sludge. Leaf litter and powder coal ash were used as cheap and easily available additives. An adsorbent for nitrogen oxide was prepared by pyrolysis of dried sludge mixed with zinc chloride. Under optimum pyrolysis conditions of 375C for 90 min and a zinc chloride content of 30%, the surface area of the adsorbent with leaf litter was 514.41 m(2)/g, the surface area of the adsorbent with powder coal ash was 432.34 m(2)/g, respectively, corresponding to an increase of 90.70% and 60.27% when compared to the adsorbent without the additives. The saturated adsorption quantity of the adsorbent with leaf litter reached 271 mg/g at 20C. The results indicated that the sludge-derived adsorbent was quite promising for nitrogen oxide removal. PMID:23063747

Ren, Xiaoli; Liang, Baohong; Liu, Min; Xu, Xiaoyuan; Cui, Meihua

2012-12-01

 
 
 
 
201

Relationship between hydrous and ordinary pyrolysis  

Energy Technology Data Exchange (ETDEWEB)

Pyrolysis results are reviewed briefly with the intent of drawing comparisons between open, high pressure, and hydrous pyrolysis. Empirically, the degree of pyrolysis severity to form volatile products in open pyrolysis is similar to that required to form an expelled oil phase in hydrous pyrolysis. The yields of hydrocarbons from open pyrolysis are close to those from hydrous pyrolysis, but hydrous pyrolysis tends to assist the separation of hydrocarbons from polar materials. Pressure has a small but measurable affect on the generation kinetics.

Burnham, A.K.

1993-06-01

202

Structural and optical properties of ZnO nanostructures grown by aerosol spray pyrolysis: Candidates for room temperature methane and hydrogen gas sensing  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We report on the synthesis of ZnO films by aerosol spray pyrolysis method at different deposition times. The surface morphology, crystal structure and the cross-sectional analysis of the prepared ZnO films were characterized by X-ray diffraction (XRD), focused ion beam scanning electron microscopy (FIB-SEM), atomic force microscopy (AFM) and high resolution transmission electron microscopy (HR-TEM). XRD analysis revealed that the ZnO films are polycrystalline in nature. Structural analysis ex...

2013-01-01

203

Pyrolysis of waste tyres: a review.  

Science.gov (United States)

Approximately 1.5 billion tyres are produced each year which will eventually enter the waste stream representing a major potential waste and environmental problem. However, there is growing interest in pyrolysis as a technology to treat tyres to produce valuable oil, char and gas products. The most common reactors used are fixed-bed (batch), screw kiln, rotary kiln, vacuum and fluidised-bed. The key influence on the product yield, and gas and oil composition, is the type of reactor used which in turn determines the temperature and heating rate. Tyre pyrolysis oil is chemically very complex containing aliphatic, aromatic, hetero-atom and polar fractions. The fuel characteristics of the tyre oil shows that it is similar to a gas oil or light fuel oil and has been successfully combusted in test furnaces and engines. The main gases produced from the pyrolysis of waste tyres are H(2), C(1)-C(4) hydrocarbons, CO(2), CO and H(2)S. Upgrading tyre pyrolysis products to high value products has concentrated on char upgrading to higher quality carbon black and to activated carbon. The use of catalysts to upgrade the oil to a aromatic-rich chemical feedstock or the production of hydrogen from waste tyres has also been reported. Examples of commercial and semi-commercial scale tyre pyrolysis systems show that small scale batch reactors and continuous rotary kiln reactors have been developed to commercial scale. PMID:23735607

Williams, Paul T

2013-08-01

204

Study of rapid pyrolysis of brown coal  

Energy Technology Data Exchange (ETDEWEB)

The paper characterizes rapid pyrolysis products gained from decomposition of hard brown coal from Kara-Kice (Kavak basin, Kirghiz SSR) and ash xylite from soft brown coal combustion in GDR power plants. Experiments were conducted on a rapid pyrolysis apparatus with a throughput of 1 kg/h and a heating rate of 1,000 K/min. Rapid pyrolysis products from hard brown coal were similar to those of black coal. The solid coke residue had a high specific surface and sorptive properties. Up to a temperature of 600 C crystal orientation in the coal was observed. Above 600 C coal decomposition and aromatization occurred. Experiments with xylite showed that increasing the heating rate had no effect on sorptive properties of the coke residue. The rate of conversion was not faster than during slow pyrolysis. A higher amount of volatiles was released during rapid pyrolysis. It is concluded that adsorption capacity cannot be further increased for coke from xylite material. (24 refs.)

Klose, E.; Dzamanbaev, A.S.; Pachridinova, A.; Born, M.; Wuntschoff, T.

1980-01-01

205

The relationship between mutagenicity and chemical composition of polycyclic aromatic compounds from coal pyrolysis.  

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The polycyclic aromatic compounds (PAC) produced from the pyrolysis of a bituminous coal at temperatures of 1125 to 1425 degrees K prove to be mutagenic to S. typhimurium, both in the presence and in the absence of postmitochondrial supernatant (PMS) prepared from Aroclor 1254-induced rat liver. Mutagenicity of the PAC samples measured in the absence of PMS exhibits little dependence on pyrolysis temperature; that measured in its presence is higher at the higher pyrolysis temperatures. Howeve...

1990-01-01

206

Thermal pyrolysis products of poly-alpha-methylstyrene  

International Nuclear Information System (INIS)

An improved process for fabrication of hollow microspheres used as innertial confinement fusion targets is the decomposable mandrel technique. Thermal gravity analysis and pyrolysis gas chromatorgraph/mass spectrometry were applied to obtaining the thermal pyrolysis behavior of poly-alpha-methylstyrene with weight-average relative molecular mass of 1.14 x 106. Ex- periment indicated that the pyrolysis temperature of poly-alpha-methylstyrene covered from 260 degree C to 320 degree C, and that of glow discharge polymer covered from 350 degree C to 420 degree C. Poly-alpha-methylstyrene degraded mostly to its monomer, alpha-methylstyrene. Tetrahydrofuran and alpha-methylstyrene dimer were found in the pyrolysis products. Tetrahydrofuran was the solvent used in preparation of poly-alpha-methylstyrene. The mass fraction of monomers was more than 99% among the pyrolysis products. (authors)

2007-08-01

207

Low-temperature atmospheric pyrolysis of coal in presence of SeO2 and liquefaction of pyrolyzed coal. Nisanka seren wo mochiita sekitan no kanetsu shori to shoritan no ekika hanno tokusei  

Energy Technology Data Exchange (ETDEWEB)

Coal given low-temperature pyrolysis with addition of SeO2 was liquefied and compared with untreated coal to discuss a possibility of pre-liquefaction treatment. The coal added with SeO2, heated in nitrogen or air, generated mainly CO2 and CO at as low temperatures as lower than 473 K. It was made clear that generation of these gases is attributed by not only oxygen in SeO2, but also part of oxygen in the coal. The SeO2 addition and heat treatment of the coal improved the liquefaction reactivity, and the catalytic effect of SeO2 and Se increased the reaction rate. Yield for pyridine and benzene solubles surpassed that with untreated coal. Liquefaction of the SeO2-treated coal consumed more hydrogen for reaction to produce pyridine solubles than the coal untreated but added with SeO2. These results indicate that the SeO2 pyrolysis has an effect to accelerate low-molecularization of reactive products while suppressing generation of water. 8 refs., 10 figs., 5 tabs.

Kiya, T.; Sanada, Y.; Chiba, T. (Hokkaido University, Sapporo (Japan). Faculty of Engineering); Nagaishi, H. (Government Industrial Development Laboratory, Hokkaido, Sapporo (Japan))

1993-08-20

208

Microwave-assisted pyrolysis of biomass for liquid biofuels production  

DEFF Research Database (Denmark)

Production of 2nd-generation biofuels from biomass residues and waste feedstock is gaining great concerns worldwide. Pyrolysis, a thermochemical conversion process involving rapid heating of feedstock under oxygen-absent condition to moderate temperature and rapid quenching of intermediate products, is an attractive way for bio-oil production. Various efforts have been made to improve pyrolysis process towards higher yield and quality of liquid biofuels and better energy efficiency. Microwave-assisted pyrolysis is one of the promising attempts, mainly due to efficient heating of feedstock by ????microwave dielectric heating???? effects. This paper presents a state-of-the-art review of microwave-assisted pyrolysis of biomass. First, conventional fast pyrolysis and microwave dielectric heating is briefly introduced. Then microwave-assisted pyrolysis process is thoroughly discussed stepwise from biomass pretreatment to bio-oil collection. The existing efforts are summarized in a table, providing a handy overview of the activities (e.g., feedstock and pretreatment, reactor/pyrolysis conditions) and findings (e.g., pyrolysis products) of various investigations.

Yin, Chungen

2012-01-01

209

Pyrolysis of scrap tyres with zeolite USY  

International Nuclear Information System (INIS)

A zeolite catalyst of ultrastable Y-type (USY) was investigated in the research of two staged pyrolysis-catalysis of scrap tyres. Scrap tyres were pyrolysed in a fixed bed reactor and the evolved pyrolysis gases were passed through a secondary catalytic reactor. The main objective of this paper was to investigate the effect of zeolite USY on the yield of products and the composition of derived oil. The influences of several parameters such as pyrolysis temperature, catalytic temperature, catalyst/tyre ratio, heating rate, etc. on the yield of the derived oil, char and gas were investigated. It showed that the increase of catalytic temperature and catalyst/tyre ratio resulted in high yield of gas at the expense of the oil yield. For example, when the catalyst/tyre ratio increased from 0.25 to 1.0, the yield of gas increased from 30.5 to 49.9 wt.%, and the oil yield decreased nearly two-fold from 31.6 to 12.7 wt.%. The concentration of light naphtha (boiling point < 160 deg. C) was also investigated in this study. And the high catalyst/tyre ratio favored to increase the concentration of light naphtha (<160 deg. C) in oil. In order to study the composition of derived oil, a distilled fraction (<280 deg. C), which was 92.5 wt.% of the oil obtained from catalytic pyrolysis of scrap tyre at a pyrolysis temperature, catalytic temperature and catalyst/tyre ratio of 500, 400 deg. C and 0.5, respectively, was analyzed with gas chromatography/mass spectrometry (GC/MS). The distillate was found to contain 1.23 wt.% benzene, 9.35 wt.% toluene, 3.68 wt.% ethylbenzene, 12.64 wt.% xylenes, 1.81 wt.% limonene and 13.89 wt.% PAHs, etc., where the single ring aromatics represented a significant potential use as chemicals

2006-09-21

210

Pyrolysis of scrap tyres with zeolite USY  

Energy Technology Data Exchange (ETDEWEB)

A zeolite catalyst of ultrastable Y-type (USY) was investigated in the research of two staged pyrolysis-catalysis of scrap tyres. Scrap tyres were pyrolysed in a fixed bed reactor and the evolved pyrolysis gases were passed through a secondary catalytic reactor. The main objective of this paper was to investigate the effect of zeolite USY on the yield of products and the composition of derived oil. The influences of several parameters such as pyrolysis temperature, catalytic temperature, catalyst/tyre ratio, heating rate, etc. on the yield of the derived oil, char and gas were investigated. It showed that the increase of catalytic temperature and catalyst/tyre ratio resulted in high yield of gas at the expense of the oil yield. For example, when the catalyst/tyre ratio increased from 0.25 to 1.0, the yield of gas increased from 30.5 to 49.9 wt.%, and the oil yield decreased nearly two-fold from 31.6 to 12.7 wt.%. The concentration of light naphtha (boiling point < 160 deg. C) was also investigated in this study. And the high catalyst/tyre ratio favored to increase the concentration of light naphtha (<160 deg. C) in oil. In order to study the composition of derived oil, a distilled fraction (<280 deg. C), which was 92.5 wt.% of the oil obtained from catalytic pyrolysis of scrap tyre at a pyrolysis temperature, catalytic temperature and catalyst/tyre ratio of 500, 400 deg. C and 0.5, respectively, was analyzed with gas chromatography/mass spectrometry (GC/MS). The distillate was found to contain 1.23 wt.% benzene, 9.35 wt.% toluene, 3.68 wt.% ethylbenzene, 12.64 wt.% xylenes, 1.81 wt.% limonene and 13.89 wt.% PAHs, etc., where the single ring aromatics represented a significant potential use as chemicals.

Shen Boxiong [College of Environmental Science and Engineering, Nankai University, Tianjin 30071 (China)]. E-mail: shenbx@nankai.edu.cn; Wu Chunfei [College of Environmental Science and Engineering, Nankai University, Tianjin 30071 (China); Wang Rui [College of Environmental Science and Engineering, Nankai University, Tianjin 30071 (China); Guo Binbin [College of Environmental Science and Engineering, Nankai University, Tianjin 30071 (China); Liang Cai [College of Environmental Science and Engineering, Nankai University, Tianjin 30071 (China)

2006-09-21

211

Production, characterization and reactivity studies of chars produced by the isothermal pyrolysis of flax straw  

International Nuclear Information System (INIS)

The influence of pyrolysis temperature and residence time on the char yields and resultant char characteristics were investigated in the isothermal pyrolysis of flax straw. The pyrolysis temperature was varied in the range between 300 and 500 C and reaction residence time was varied from 15 to 60 min. The char yield was found to decrease with both increasing pyrolysis temperature and residence time. The char structure and physical characteristics were thoroughly investigated by means of X-ray diffraction (XRD), temperature-programmed oxidation (TPO) and N2 physisorption techniques. The results show that the degree of porosity and graphitization increased with increasing pyrolysis temperature and time. TPO studies on the char samples corroborate well with the XRD findings and showed the presence of two types of carbon; namely, amorphous filamentous carbon and crystalline graphitic carbon. Thermogravimetric analysis (TGA) of the char was performed to understand the combustion kinetics and reactivity. Chars formed at lower pyrolysis temperatures were found to be more reactive than the chars produced at higher pyrolysis temperatures, and these findings are well supported by the TPO, TGA, N2 physisorption and XRD characterization data. Furthermore, an empirical global kinetic model was devised based on power law and used to estimate the activation energy and other kinetic parameters of both flax straw pyrolysis and char combustion processes. -- Highlights: ? The results show conditions to obtain reactive chars from pyrolysis of flax straw. ? A higher pyrolysis temperature leads to a higher amount of nonreactive chars. ? A longer reaction time leads to a higher amount of nonreactive chars. ? A lower pyrolysis temperature and a shorter residence time lead to reactive chars. ? Pyrolysis temperature has a stronger effect on char reactivity than residence time.

2012-02-01

212

The Cyclic Strain Rate Dependence on Environmentally Assisted Cracking Behaviors of SA508 Gr. 1a Low Alloy Steel in 310 .deg. C Deoxygenated Water  

International Nuclear Information System (INIS)

Environmental fatigue damage is well known as a significant degradation mechanism in nuclear power plant (NPP). So, the environmental fatigue behaviors should be cautiously considered for assessment of the integrity and the safety of NPP. In result of many researches, it is reported that the reduction in fatigue life of low alloy steels (LASs) is induced by the environmentally assisted cracking (EAC) mechanisms, such as the metal dissolution and the hydrogen-induced cracking (HIC). However, since these mechanisms are usually influenced by multiple factors, there are no clear explanations about fatigue cracking behaviors in high temperature water. In this study, low cycle fatigue (LCF) tests were conducted to investigate the fatigue life of SA508 Gr. 1a LAS in 310 .deg. C deoxygenated water. Also, the fatigue surface and sectioned area were observed for evaluation of cyclic strain rate dependent EAC mechanism in high temperature water

2007-05-10

213

Intramuscular deoxygenation during exercise in patients who have chronic anterior compartment syndrome of the leg  

Science.gov (United States)

Currently, the definitive diagnosis of chronic compartment syndrome is based on invasive measurements of intracompartmental pressure. We measured the intramuscular pressure and the relative oxygenation in the anterior compartment of the leg in eighteen patients who were suspected of having chronic compartment syndrome as well as in ten control subjects before, during, and after exercise. Chronic compartment syndrome was considered to be present if the intramuscular pressure was at least fifteen millimeters of mercury (2.00 kilopascals) before exercise, at least thirty millimeters of mercury (4.00 kilopascals) one minute after exercise, or at least twenty millimeters of mercury (2.67 kilopascals) five minutes after exercise. Changes in relative oxygenation were measured with use of the non-invasive method of near-infrared spectroscopy. In all patients and subjects, there was rapid relative deoxygenation after the initiation of exercise, the level of oxygenation remained relatively stable during continued exercise, and there was reoxygenation to a level that exceeded the pre-exercise resting level after the cessation of exercise. During exercise, maximum relative deoxygenation in the patients who had chronic compartment syndrome (mean relative deoxygenation [and standard error], -290 +/- 39 millivolts) was significantly greater than that in the patients who did not have chronic compartment syndrome (-190 +/- 10 millivolts) and that in the control subjects (-179 +/- 14 millivolts) (p < 0.05 for both comparisons). In addition, the interval between the cessation of exercise and the recovery of the pre-exercise resting level of oxygenation was significantly longer for the patients who had chronic compartment syndrome (184 +/- 54 seconds) than for the patients who did not have chronic compartment syndrome (39 +/- 19 seconds) and the control subjects (33 +/- 10 seconds) (p < 0.05 for both comparisons).

Mohler, L. R.; Styf, J. R.; Pedowitz, R. A.; Hargens, A. R.; Gershuni, D. H.

1997-01-01

214

Non-thermal radio frequency and static magnetic fields increase rate of hemoglobin deoxygenation in a cell-free preparation.  

Science.gov (United States)

The growing body of clinical and experimental data regarding electromagnetic field (EMF) bioeffects and their therapeutic applications has contributed to a better understanding of the underlying mechanisms of action. This study reports that two EMF modalities currently in clinical use, a pulse-modulated radiofrequency (PRF) signal, and a static magnetic field (SMF), applied independently, increased the rate of deoxygenation of human hemoglobin (Hb) in a cell-free assay. Deoxygenation of Hb was initiated using the reducing agent dithiothreitol (DTT) in an assay that allowed the time for deoxygenation to be controlled (from several min to several hours) by adjusting the relative concentrations of DTT and Hb. The time course of Hb deoxygenation was observed using visible light spectroscopy. Exposure for 10-30 min to either PRF or SMF increased the rate of deoxygenation occurring several min to several hours after the end of EMF exposure. The sensitivity and biochemical simplicity of the assay developed here suggest a new research tool that may help to further the understanding of basic biophysical EMF transduction mechanisms. If the results of this study were to be shown to occur at the cellular and tissue level, EMF-enhanced oxygen availability would be one of the mechanisms by which clinically relevant EMF-mediated enhancement of growth and repair processes could occur. PMID:23593496

Muehsam, David; Lalezari, Parviz; Lekhraj, Rukmani; Abruzzo, Provvidenza; Bolotta, Alessandra; Marini, Marina; Bersani, Ferdinando; Aicardi, Giorgio; Pilla, Arthur; Casper, Diana

2013-01-01

215

CATALYTIC THERMAL DECOMPOSITION OF POLYETHYLENE BY PYROLYSIS GAS CHROMATOGRAPHY  

Directory of Open Access Journals (Sweden)

Full Text Available An experimental study of the thermal decomposition of polyethylene in an inert atmosphere has been carried out in the temperature range 300-800C using Shimadzu PYR-2A pyrolyzer for heating the sample. The method allows the accurate control and measurement of the pyrolysis temperature. The production of hydrocarbons and the corresponding monomers of these polymeric systems were monitored. The effects of variation of temperature, sample size, pyrolysis atmosphere, residence time and catalyst on the distribution of these products were studied. As the carrier gas rapidly swept the primary products from the hot zone into the chromatographic column, so the secondary decomposition is largely eliminated and the pyrolysis products give accurate information about the nature, composition and structure of the pyrolysis material.

JAN NISAR

2011-01-01

216

CATALYTIC THERMAL DECOMPOSITION OF POLYETHYLENE BY PYROLYSIS GAS CHROMATOGRAPHY  

Scientific Electronic Library Online (English)

Full Text Available SciELO Chile | Language: English Abstract in english An experimental study of the thermal decomposition of polyethylene in an inert atmosphere has been carried out in the temperature range 300-800C using Shimadzu PYR-2A pyrolyzer for heating the sample. The method allows the accurate control and measurement of the pyrolysis temperature. The productio [...] n of hydrocarbons and the corresponding monomers of these polymeric systems were monitored. The effects of variation of temperature, sample size, pyrolysis atmosphere, residence time and catalyst on the distribution of these products were studied. As the carrier gas rapidly swept the primary products from the hot zone into the chromatographic column, so the secondary decomposition is largely eliminated and the pyrolysis products give accurate information about the nature, composition and structure of the pyrolysis material.

NISAR, JAN; ALI, MUKHTIAR; AHMAD AWAN, IFTIKHAR.

217

Orientation-dependent low field magnetic anomalies and room-temperature spintronic material - Mn doped ZnO films by aerosol spray pyrolysis  

Digital Repository Infrastructure Vision for European Research (DRIVER)

High quality un-doped and Mn-doped ZnO films deposited by a simple aerosol spray pyrolysis technique for 20 and 30 min were studied using electron paramagnetic resonance (EPR), X-ray diffraction (XRD) and atomic force microscopy (AFM) techniques. EPR analysis showed novel observation of low field microwave absorption (LFMA) on the manganese (Mn) doped zinc oxide (ZnO) films at various Mn concentrations. The results showed a peculiar behavior, reversal signal to that of LFMA. These findings al...

2013-01-01

218

Vacuum pyrolysis of swine manure : biochar production and characteristics  

Energy Technology Data Exchange (ETDEWEB)

Quebec accounts for nearly 25 per cent of swine production in Canada. The issue of swine manure is addressed through land spreading and conversion into fertilizer. However, current regulations restrict the use of swine manure as fertilizer on most farmlands due to the problem of surplus phosphorus and nitrogen. Although many technologies exist to separate phosphorus and nitrogen from the organic-rich dry matter in swine manure, about 40 per cent of the treated waste matter must still be disposed in an environmentally sound manner. This study investigated the technical feasibility of pretreating the swine manure solids into biofuels on a farm-scale basis using vacuum pyrolysis process. A custom built stainless steel pressure vessel was used to carry out pyrolysis reaction of swine manure biomass at a temperature range between 200 to 600 degrees C under vacuum. The pyrolytic vapour was condensed in 2 glass condensers in series. The biochar was collected directly from the pyrolysis vessel following completion of the pyrolysis batch. The non condensable vapour and gases were considered as losses. Biochar, bio-oil, an aqueous phase and a gas mixture were the 4 products of the pyrolysis process. A thermogravimetric analysis of the swine manure samples was conducted before the pyrolysis tests. The study showed that 238 degrees C is the optimal pyrolysis temperature for biochar production.

Verma, M. [Inst. de recherche et de developpement en agroenvironnement Inc., Quebec City, PQ (Canada); Centre de recherche industrielle du Quebec, Quebec City, PQ (Canada); Godbout, S.; Larouche, J.P.; Lemay, S.P.; Pelletier, F. [Inst. de recherche et de developpement en agroenvironnement Inc., Quebec City, PQ (Canada); Solomatnikova, O. [Centre de recherche industrielle du Quebec, Quebec City, PQ (Canada); Brar, S.K. [Inst. national de la recherche scientifique, eau, terre et environnement, Quebec City, PQ (Canada)

2010-07-01

219

A unified biomass-coal pyrolysis reaction model  

Energy Technology Data Exchange (ETDEWEB)

A unified first order reaction rate model of pyrolysis is presented to facilitate co-utilization of domestic fuels (CDF) spanning the entire coalification region. This model was first used in interpretations of University of Florida laboratory and industrial scale coal-natural gas (C-NG) co-firing experiments using reaction rates based upon coal pyrolysis yields measured at MIT. After undertaking industrial-scale municipal solid waste, biomass, coal, and natural gas co-firing experiments, the pyrolysis model was used to interpret experiments with these fuels. The model is adapted to represent ultra pyrolysis (UP) yields of cellulose measured at the University of Western Ontario (UWO) and fast pyrolysis (FP) yields of eight coals of various ranks measured at Tohoku University. The overall goal is to find equations to calculate FP yields that depend upon the weight percentages (C), (H) and (O) of the feedstock, the a, b, c of the chemical product (C{sub a}H{sub b}O{sub c}), the temperature of pyrolysis (T) and the time (t) of application of this temperature. Such a unified model should be useful for many CDF applications and helpful in bringing order to the science of pyrolysis. 37 refs., 3 figs., 1 tab.

Green, A.E.S.; Chaube, R.P. [University of Florida, Gainesville, FL (United States). Clean Combustion Technology Lab.

2004-07-01

220

Additives initiate selective production of chemicals from biomass pyrolysis.  

Science.gov (United States)

To improve chemicals selectivity under low temperature, a new method that involves the injection of additives into biomass pyrolysis is introduced. This method allows biomass pyrolysis to achieve high selectivity to chemicals under low temperature (300C), while nothing was obtained in typical pyrolysis under 300C. However, by using the new method, the first liquid drop emerged at the interval between 140C and 240C. Adding methanol to mushroom scrap pyrolysis obtained high selectivity to acetic acid (98.33%), while adding ethyl acetate gained selectivity to methanol (65.77%) in bagasse pyrolysis and to acetone (72.51%) in corncob pyrolysis. Apart from basic chemicals, one high value-added chemical (2,3-dihydrobenzofuran) was also detected, which obtained the highest selectivity (10.33%) in corncob pyrolysis through the addition of ethyl acetate. Comparison of HZSM-5 and CaCO3 catalysis showed that benzene emerged in the liquid because of the larger degree of cracking and hydrodeoxygenation over HZSM-5. PMID:24508091

Leng, Shuai; Wang, Xinde; Wang, Lei; Qiu, Huizhe; Zhuang, Guilin; Zhong, Xing; Wang, Jianguo; Ma, Fengyun; Liu, Jingmei; Wang, Qiang

2014-03-01

 
 
 
 
221

PYROLYSIS AND COMBUSTION OF SCRAP TIRE  

Directory of Open Access Journals (Sweden)

Full Text Available In this paper a literature review of both pyrolysis and combustion processes of scrap tires is presented. The work reports, the characteristics of materials, methods, effect of various process parameters, kinetic modelling applied to the pyrolysis and combustion of tires, characteristics of the products and emissions. From the published works results that scrap tire rubber consists of about 60 wt.% volatile organics, 30 wt.% fixed carbon and 10 wt.% ash. Elemental analysis shows that tire rubber contains approximately 80 wt.% of C, 7 wt. of H, 0.4 wt.% of N, 1.5 wt.% of S, 3 wt.% of O and 8 wt.% of ash. Thermogravimetry analysis reveals that the pyrolysis of tire rubber at atmospheric pressure starts at a temperature around 250oC and finishes at a temperature of about 550oC. Generally, more than one degradation temperature region during rubber pyrolysis is recorded. In general, by pyrolysing waste tire three fractions are obtained: solid residue (around 40 wt.%, liquid fraction (around 50 wt.% and gas fraction (around 10 wt.%. The influence of the process conditions on the amount and characteristics of individual fractions was studied by the authors only partially. The general trend is an increase in yields of liquid and gas fractions as the temperature increases. From the works devoted to tire pyrolysis, which are focussed on the generation of liquid fuel results that derived liquids are a complex mixture of organic compounds containing a lot of aromatics. This liquid can be separated into light and higher fractions. The main components of pyrolysis gases reported by various authors are as: H2, H2S, CO, CO2, CH4, C2H4, C3H6 and other light hydrocarbons. The solid residue contains carbon black, and inorganic matter. The results of kinetic modelling of scrap tire pyrolysis and combustion show large differences in the values of kinetic parameters obtained by different authors. As main pollutants from the combustion of waste tires are reported: SO2, NOx, CO and PAHs.

?. Jelemensk

2006-02-01

222

Accuracy and Potential Use of a Developed CFD-pyrolysis Model for Simulating Lab-scale Bio Oil Production  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The paper describes development of a CFDpyrolysis model using an Eularian-Eularian framework with an implemented pyrolysis reaction model. The CFDpyrolysis model is used to simulate the bubbling fluidized bed reactor integrated in a new experimental fast pyrolysis process for bio oil production. The model is compared to experiments in aspect of outlet gas composition, temperature and bed height. Tar behavior and yield of bio oil are illustrated and a parametric study investigates impact o...

Mellin, Pelle; Zhang, Qinglin; Kantarelis, Efthymios; Zhou, Chunguang; Yang, Weihong

2012-01-01

223

Residua pyrolysis and coke formation  

Energy Technology Data Exchange (ETDEWEB)

This study focused on the changes occurring in petroleum residua during the pyrolysis. To keep the overall system free energy at a minimum, it appears that asphaltenes self-adjust their apparent molecular weights to match the polarity of the solvent phase as closely as possible. The solubility parameters of the maltenes and asphaltenes increase, and the apparent molecular weight of the asphaltenes decreases as the thermal treatment progresses. The depletion of the intermediate polarity resins material reduces the ability of the asphaltenes to remain dispersed in the system, resulting in an unstable system. When this situation happens, the formation of a multi-phase system occurs, followed by coking. Two new Coking Indexes wee developed, on the basis of the asphaltene flocculation titration and the cyclohexane soluble portion of heptane asphaltenes. The p{sub a} divided by C{sub min} ratio based on Heithaus titration data is the first. The measurement of the weight percent cyclohexane solubles in heptane asphaltenes divided by the weight percent of heptane asphaltenes defines the second. The determination of these Indexes was effected for a wide array of residua materials undergoing pyrolysis. Regardless of the source of the material, the Coking Indexes seem to apply universally for residua. The nearness of a system to coke formation during the coke formation induction period is indicated by the Coking Indexes. The development of predictors for pyrolytic coke formation was performed using the dispersed particle solution model of petroleum residua structure. During the pyrolysis, the amount of coke initially formed seems to be a function of the free solvent volume of the original residuum. The three-dimensional coke make predictability maps at 400 degrees Celsius, 450 degrees Celsius and 500 degrees Celsius was developed using this relationship. Residence time and free solvent volume are related to the amount of coke formed at a particular pyrolysis temperature. At completion, the amount of coke formed is a function of the atomic hydrogen divided by carbon ratio. New tools for ranking residua, gauging proximity to coke formation, and the predicting of initial coke make tendencies resulted from this work. tabs., 78 figs.

Schabron, J.F. [Western Research Institute, Laramie, WY (United States)

2001-07-01

224

Microwave pyrolysis of microalgae for high syngas production  

Digital Repository Infrastructure Vision for European Research (DRIVER)

[EN]The microwave induced pyrolysis of the microalga Scenedesmus almeriensis and its extraction residue was carried out at 400 and 800 C. The results show that it is possible to obtain a gas fraction with a high content (c.a. 50 vol.%) in H2 from both materials, regardless of the pyrolysis temperature. Furthermore, an outstanding syngas production and high gas yields were achieved. The maximum syngas concentration obtained was c.a. 94 vol.%, in the case of the pyrolysis of th...

Beneroso Vallejo, Daniel; Bermu?dez Mene?ndez, Jose? Miguel; Arenillas La Puente, Ana; Mene?ndez Di?az, Jose? A?ngel

2013-01-01

225

Pyrolysis and hydrolysis of mixed polymer waste comprising polyethyleneterephthalate and polyethylene to sequentially recover  

Energy Technology Data Exchange (ETDEWEB)

A process of using fast pyrolysis in a carrier gas to convert a plastic waste feedstream having a mixed polymeric composition in a manner such that pyrolysis of a given polymer to its high value monomeric constituent occurs prior to pyrolysis of other plastic components therein comprising: selecting a first temperature program range to cause pyrolysis of said given polymer to its high value monomeric constituent prior to a temperature range that causes pyrolysis of other plastic components; selecting a catalyst and support for treating said feed streams with said catalyst to effect acid or base catalyzed reaction pathways to maximize yield or enhance separation of said high value monomeric constituent in said temperature program range; differentially heating said feed stream at a heat rate within the first temperature program range to provide differential pyrolysis for selective recovery of optimum quantities of the high value monomeric constituent prior to pyrolysis of other plastic components; separating the high value monomeric constituents; selecting a second higher temperature range to cause pyrolysis of a different high value monomeric constituent of said plastic waste and differentially heating the feedstream at the higher temperature program range to cause pyrolysis of the different high value monomeric constituent; and separating the different high value monomeric constituent.

Evans, Robert J. (Lakewood, CO); Chum, Helena L. (Arvada, CO)

1998-01-01

226

Flash pyrolysis of jatropha oil cake in electrically heated fluidized bed reactor  

International Nuclear Information System (INIS)

Fluidized bed flash pyrolysis experiments have been conducted on a sample of jatropha oil cake to determine particularly the effects of particle size, pyrolysis temperature and nitrogen gas flow rate on the pyrolysis yields. The particle size, nitrogen gas flow rate and temperature of jatropha oil cake were varied from 0.3 to 1.18 mm, 1.25 to 2.4 m3/h and 350 to 550 oC. The maximum oil yield of 64.25 wt% was obtained at a nitrogen gas flow rate of 1.75 m3/h, particle size of 0.7-1.0 mm and pyrolysis temperature of 500 oC. The calorific value of pyrolysis oil was found to be 19.66 MJ/kg. The pyrolysis gas can be used as a gaseous fuel.

2010-07-01

227

Nitrogen gas purging for the deoxygenation of polyaromatic hydrocarbon solutions in cyclohexane for routine fluorescence analysis.  

Science.gov (United States)

During routine fluorescence analysis, the presence of dissolved oxygen in solutions can result in the dynamic quenching of a fluorophore's emission through collisional deexcitation of the fluorophore's excited state. In order to avoid this type of fluorescence quenching, dissolved oxygen is often removed from solutions by an inert gas purging procedure. However, the details and quantification of this purging process are often limited in fluorescence studies. In this work, standard 10 mm x 10 mm fluorescence cuvettes are filled with polyaromatic hydrocarbon (PAH) solutions in cyclohexane and purged using nitrogen gas, and the experimental purging parameters (nitrogen flow rate, amount of volatile solvent loss, and rate of oxygen removal) are measured and analyzed. For experimental conditions similar to those used in this study, we are able to provide useful guidelines for the deoxygenation of solutions, specifically the purge times required for solutions of fluorophores with various fluorescence lifetimes. Enhancement factors, or F(0)/F values (the ratio of fluorescence intensity of a completely deoxygenated solution to the fluorescence intensity of an aerated solution), for chrysene, phenanthrene, naphthalene, and pyrene solutions in cyclohexane were found to be 3.61 +/- 0.02, 4.17 +/- 0.02, 7.63 +/- 0.07, and 21.81 +/- 0.35, respectively. PMID:18339243

Pagano, Todd; Biacchi, Adam J; Kenny, Jonathan E

2008-03-01

228

Models and past ocean de-oxygenation: ';nice' is not a statistical measure of understanding (Invited)  

Science.gov (United States)

Over the past decade(s), numerical model assessment and interpretation of the increasingly temporally, spatially, and multi-proxy resolved geological record of ocean de-oxygenation has frequently claimed to have been ';successful' in reproducing the ';main' ';features' or ';patterns', as well as often the ';approximate' or ';same order' of ';magnitude', and overall obtaining ';close', ';reasonable', ';pleasing', or downright ';cute' (disclaimer: I made this last one up) fits to the data. In contrast, present-day model oceanographic circles, statistical measures have become de rigueur to the point every Powerpoint slide must legally contain at least one sectoral ';Taylor Diagram'. However, model-data approaches developed in the context of modern observations are not necessarily directly translatable to deeper time, when data constraints are more sparse with often considerable temporal and depth uncertainties and for which the proxies may not be fully quantitative, and even when they are, inherently contain large (often calibration) uncertainties. Bridging this gap is difficult, but ';paleo' must move towards embracing a more quantitative assessment of proxies with models if we are to maintain credibility to inform future projections and impacts. Here I will present some case-studies, both good and bad, of how models and data can be combined in the contact of better understanding past ocean de-oxygenation.

Ridgwell, A. J.

2013-12-01

229

The impact of ocean deoxygenation on iron release from continental margin sediments  

Science.gov (United States)

In the oceans' high-nitrate-low-chlorophyll regions, such as the Peru/Humboldt Current system and the adjacent eastern equatorial Pacific, primary productivity is limited by the micronutrient iron. Within the Peruvian upwelling area, bioavailable iron is released from the reducing continental margin sediments. The magnitude of this seafloor source could change with fluctuations in the extension or intensity of the oxygen minimum zones. Here we show that measurements of molybdenum, uranium and iron concentrations can be used as a proxy for sedimentary iron release, and use this proxy to assess iron release from the sea floor beneath the Peru upwelling system during the past 140,000 years. We observe a coupling between levels of denitrification, as indicated by nitrogen isotopes, trace metal proxies for oxygenation, and sedimentary iron concentrations. Specifically, periods with poor upper ocean oxygenation are characterized by more efficient iron retention in the sediment and a diminished iron supply to the water column. We attribute efficient iron retention under more reducing conditions to widespread sulphidic conditions in the surface sediment and concomitant precipitation of iron sulphides. We argue that iron release from continental margin sediments is most effective in a narrow redox window where neither oxygen nor sulphide is present. We therefore suggest that future deoxygenation in the Peru upwelling area would be unlikely to result in increased iron availability, whereas in weaker oxygen minimum zones partial deoxygenation may enhance the iron supply.

Scholz, Florian; McManus, James; Mix, Alan C.; Hensen, Christian; Schneider, Ralph R.

2014-06-01

230

Laboratory evaluation of a Pd-based catalyst for deoxygenation of stator cooling water  

Energy Technology Data Exchange (ETDEWEB)

The water-cooled stator windings in turbine generators suffer from various forms of corrosion induced by the presence of dissolved oxygen. In the current study, various laboratory experiments were conducted to identify a suitable catalyst for the deoxygenation of stator cooling water (SCW) systems and to qualify the material to be used in a field trial in order to confirm its deoxygenation performance. The work focused on evaluating the Lanxess (formerly Bayer) Lewatit K 7333 catalyst with respect to its physical, chemical, and oxidation stability through accelerated ageing tests as well as its performance under extreme dissolved oxygen and hydrogen concentrations. Potential effects of any water extractable leachables from the catalyst on the materials of construction of the SCW system were also studied. The catalyst was effective in removing dissolved oxygen in the presence of dissolved hydrogen and should be able to meet or exceed the dissolved oxygen specifications ({<=} 20 {mu}g . kg{sup -1}) for SCW stations that operate under low-oxygen mode. (orig.)

Dias, Shelton; Rudolph, Andreas [Kinectrics Inc., Toronto, ON (Canada)

2010-02-15

231

Laboratory evaluation of a Pd-based catalyst for deoxygenation of stator cooling water  

International Nuclear Information System (INIS)

The water-cooled stator windings in turbine generators suffer from various forms of corrosion induced by the presence of dissolved oxygen. In the current study, various laboratory experiments were conducted to identify a suitable catalyst for the deoxygenation of stator cooling water (SCW) systems and to qualify the material to be used in a field trial in order to confirm its deoxygenation performance. The work focused on evaluating the Lanxess (formerly Bayer) Lewatit K 7333 catalyst with respect to its physical, chemical, and oxidation stability through accelerated ageing tests as well as its performance under extreme dissolved oxygen and hydrogen concentrations. Potential effects of any water extractable leachables from the catalyst on the materials of construction of the SCW system were also studied. The catalyst was effective in removing dissolved oxygen in the presence of dissolved hydrogen and should be able to meet or exceed the dissolved oxygen specifications (? 20 ?g . kg-1) for SCW stations that operate under low-oxygen mode. (orig.)

2010-02-01

232

Vacuum pyrolysis of waste tires with basic additives.  

Science.gov (United States)

Granules of waste tires were pyrolyzed under vacuum (3.5-10 kPa) conditions, and the effects of temperature and basic additives (Na2CO3, NaOH) on the properties of pyrolysis were thoroughly investigated. It was obvious that with or without basic additives, pyrolysis oil yield increased gradually to a maximum and subsequently decreased with a temperature increase from 450 degrees C to 600 degrees C, irrespective of the addition of basic additives to the reactor. The addition of NaOH facilitated pyrolysis dramatically, as a maximal pyrolysis oil yield of about 48 wt% was achieved at 550 degrees C without the addition of basic additives, while a maximal pyrolysis oil yield of about 50 wt% was achieved at 480 degrees C by adding 3 wt% (w/w, powder/waste tire granules) of NaOH powder. The composition analysis of pyrolytic naphtha (i.b.p. (initial boiling point) approximately 205 degrees C) distilled from pyrolysis oil showed that more dl-limonene was obtained with basic additives and the maximal content of dl-limonene in pyrolysis oil was 12.39 wt%, which is a valuable and widely-used fine chemical. However, no improvement in pyrolysis was observed with Na2CO3 addition. Pyrolysis gas was mainly composed of H2, CO, CH4, CO2, C2H4 and C2H6. Pyrolytic char had a surface area comparable to commercial carbon black, but its proportion of ash (above 11.5 wt%) was much higher. PMID:18162390

Zhang, Xinghua; Wang, Tiejun; Ma, Longlong; Chang, Jie

2008-11-01

233

Vacuum pyrolysis of waste tires with basic additives  

International Nuclear Information System (INIS)

Granules of waste tires were pyrolyzed under vacuum (3.5-10 kPa) conditions, and the effects of temperature and basic additives (Na2CO3, NaOH) on the properties of pyrolysis were thoroughly investigated. It was obvious that with or without basic additives, pyrolysis oil yield increased gradually to a maximum and subsequently decreased with a temperature increase from 450 deg. C to 600 deg. C, irrespective of the addition of basic additives to the reactor. The addition of NaOH facilitated pyrolysis dramatically, as a maximal pyrolysis oil yield of about 48 wt% was achieved at 550 deg. C without the addition of basic additives, while a maximal pyrolysis oil yield of about 50 wt% was achieved at 480 deg. C by adding 3 wt% (w/w, powder/waste tire granules) of NaOH powder. The composition analysis of pyrolytic naphtha (i.b.p. (initial boiling point) ?205 deg. C) distilled from pyrolysis oil showed that more dl-limonene was obtained with basic additives and the maximal content of dl-limonene in pyrolysis oil was 12.39 wt%, which is a valuable and widely-used fine chemical. However, no improvement in pyrolysis was observed with Na2CO3 addition. Pyrolysis gas was mainly composed of H2, CO, CH4, CO2, C2H4 and C2H6. Pyrolytic char had a surface area comparable to commercial carbon black, but its proportion of ash (above 11.5 wt%) was much higher

2008-11-01

234

Resource Recovery by Pyrolysis.  

Science.gov (United States)

While by means of the conventional pyrolysis technologies it was possible to treat one specific waste only, it is the aim of this project to develop a technology which enables to process a great number of hydrocarbonaceous industrial wastes, even in mixtu...

B. Andreas W. Birckenstaedt G. P. Bracker G. Collin G. Grigoleit

1981-01-01

235

ENGINEERING BULLETIN: PYROLYSIS TREATMENT  

Science.gov (United States)

Pyrolysis is formally defined as chemical decomposition induced in organic materials by heat in the absence of oxygen. In practice, it is not possible to achieve a completely oxygen-free atmosphere; actual pyrolytic systems are operated with less than stoichiometric quantities of...

236

Pyrolysis of used automobile tires and residual char utilization  

Energy Technology Data Exchange (ETDEWEB)

In the present study the rubber portion of used car tires was transformed by atmospheric pyrolysis into oil, gas and char. The experiments have been performed in a captive sample reactor at atmospheric pressure, under helium atmosphere. The effect of temperature on the products yield was investigated. In a second step, alternative uses of pyrolysis char such as combustion, gasification and active carbons preparation were examined, in order to produce fuels and high added value materials. First, pyrolysis char was burned and its reactivity was measured in function with pyrolysis temperature. Second, char was gasified with Steam and CO{sub 2} to produce fuel gases, in a tubular stainless steel reactor. It was also activated to produce high added value materials. It was shown that tire chars present higher reactivity with steam than with CO{sub 2} and also active carbons produced from tire chars possess surface areas, comparable with those of commercially available active carbons.

Zabaniotou, A.A.; Stavropoulos, G. [Department of Chemical Engineering, Aristotle University of Thessaloniki, Univ. Box 455, GR-54006 Thessaloniki (Greece)

2003-12-01

237

Volume reduction of ion exchange resin by a pyrolysis technique  

International Nuclear Information System (INIS)

Volume reduction techniques, such as incineration and acid digestion, of spent ion exchange resins from nuclear power plants are being developed with a view toward reducing radioactive waste volume and also making the final waste form more stable. The authors chose pyrolysis as a technique that can be done at low operating temperatures and low gas flow rates in a reactor vessel. Fundamental experiments were performed to clarify the resin pyrolysis characteristics, and the optimum pyrolysis temperature was determined. Consequently, a pilot plant with a treatment capacity of approx. 50 kg/batch was constructed based on the results. Using the pilot plant, the authors are now performing pyrolysis of the resins and solidification of their residues. This report will give the results of fundamental experiments and pilot plant tests

1985-11-01

238

Pyrolysis of Pine Wood, Experiments and Theory  

DEFF Research Database (Denmark)

In this study, pinewood has been pyrolyzed using a fixed heating rate with a variable end-temperature. The pyrolysis process has been simulated using a mechanism with three parallel reactions for the formation of char, gas and tar. First order irreversible kinetics is assumed. This kind of model may predict the variation of product yield with operating conditions such as temperature and heating rate. The system of coupled differential equations describing the pyrolysis process is solved using the software DYMOLA. Various literature values for kinetic parameters have been compared with the experimental values. In this work the model was able to predict the volatile amount as a function of temperature in the interval from 250 to 1000°C with a good accuracy.

Fjellerup, Jan Søren; Ahrenfeldt, Jesper

239

Pyrolysis of Pine Wood : Experiments and Theory  

DEFF Research Database (Denmark)

In this study, pinewood has been pyrolyzed using a fixed heating rate with a variable end-temperature. The pyrolysis process has been simulated using a mechanism with three parallel reactions for the formation of char, gas and tar. First order irreversible kinetics is assumed. This kind of model may predict the variation of product yield with operating conditions such as temperature and heating rate. The system of coupled differential equations describing the pyrolysis process is solved using the software DYMOLA. Various literature values for kinetic parameters have been compared with the experimental values. In this work the model was able to predict the volatile amount as a function of temperature in the interval from 250 to 1000°C with a good accuracy.

Fjellerup, Jan Søren; Ahrenfeldt, Jesper

2005-01-01

240

Solid waste utilization: pyrolysis  

Energy Technology Data Exchange (ETDEWEB)

As a part of the Integrated Community Energy System (ICES) Program, a number of technology evaluations are being prepared on various current and emerging sources of energy. This evaluation considers the use of pyrolysis as a method of producing energy from municipal solid waste. The energy can be in the form of a gas, oil, chars, or steam. Pyrolysis, the decomposition of organic matter in the absence of oxygen (or in an oxygen-deficient atmosphere), has been used to convert organic matter to other products or fuels. This process is also described as ''destructive distillation''. Four processes are described in detail: the ''Landgard'' System (Monsanto Environ-Chem Systems, Inc.); the Occidental Research Corporation Process (formerly the Garrett Research and Development Company; The ''Purox'' System (Union Carbide Corporation); and the ''Refu-Cycler'' (Hamilton Standard Corporation). ''Purox'' and ''Refu-Cycler'' produce a low-Btu gas; the Occidental process produces an oil, and the ''Landgard'' process produces steam using on-site auxiliary boilers to burn the fuel gases produced by the pyrolysis unit. Also included is a listing of other pyrolysis processes currently under development for which detailed information was not available. The evaluation provides information on the various process flowsheets, energy and material balances, product characteristics, and economics. Pyrolysis of municipal solid waste as an energy source can be considered a potential for the future; however little operational or economic information is available at this time.

Boegly, W.J. Jr.; Mixon, W.R.; Dean, C.; Lizdas, D.J.

1977-08-01

 
 
 
 
241

SPHERICAL CALCIA STABILIZED ZIRCONIA POWDERS OBTAINED BY SPRAY PYROLYSIS  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Physical and chemical properties of ceramic powders are highly dependent on the morphology and chemical composition of the precursor powders. Therefore, properties of ceramic powders are expecting to be improved by controlling the most important parameters of morphology such as composition of precursors, temperature and airflow. Promising techniques to produce ceramic powders with controlled morphology are sol-gel, coprecipitation, and pyrolysis. Among these techniques, spray pyrolysis is one...

Esparza-ponce, H. E.; Reyes-rojas, A.; Miki Yoshida, M.

2001-01-01

242

Kajian Pembuatan Nanotube Karbon dengan Menggunakan Metode Spray Pyrolysis  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Dalam penelitian ini, nanotube karbon dibuat dengan menggunakan metode spray pyrolysis tanpa menggunakan gas pembawa pada temperatur 850C. Metode ini merupakan metode yang sering digunakan dalam sintesis nanotube karbon karena dapat menghasilkan nanotube karbon dengan kualitas yang baik dengan biaya produksi yang murah. Dalam spray pyrolysis, benzene sebagai sumber karbon terdekomposisi secara termal dengan bantuan ferrocene yang berperan sebagai katalis dalam menghasilkan nanotube karbon. ...

2009-01-01

243

Influence of Pyrolysis Parameters on the Performance of CMSM  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Carbon hollow fiber membranes have been prepared by pyrolysis of a P84/S-PEEK blend. Proximate analysis of the precursor was performed using thermogravimetry (TGA), and a carbon yield of approximately 40% can be obtained. This study aimed at understanding the influence of pyrolysis parametersend temperature, quenching effect, and soaking timeon the membrane properties. Permeation experiments were performed with N2, He, and CO2. Scanning electron microscopy (SEM) has been don...

Campo, Marta C.; Tymen Visser; Kitty Nijmeijer; Matthias Wessling; Magalh Es, Fern O. D.; Mendes, Ad Lio M.

2009-01-01

244

Analysis of cyclic pyrolysis products formed from amino acid monomer.  

Science.gov (United States)

Amino acid was mixed with silica and tetramethylammonium hydroxide (TMAH) to favor pyrolysis of amino acid monomer. The pyrolysis products formed from amino acid monomer were using GC/MS and GC. 20 amino acids of alanine, arginine, asparagine, aspartic acid, cysteine, glutamic acid, glutamine, glycine, histidine, isoleucine, leucine, lysine, methionine, phenylalanine, proline, serine, threonine, tryptophan, tyrosine, and valine were analyzed. The pyrolysis products were divided into cyclic and non-cyclic products. Among the 20 amino acids, arginine, asparagine, glutamic acid, glutamine, histidine, lysine, and phenylalanine generated cyclic pyrolysis products of the monomer. New cyclic pyrolysis products were formed by isolation of amino acid monomers. They commonly had polar side functional groups to 5-, 6-, or 7-membered ring structure. Arginine, asparagine, glutamic acid, glutamine, histidine, and phenylalanine generated only 5- or 6-membered ring products. However, lysine generated both 6- and 7-membered ring compounds. Variations of the relative intensities of the cyclic pyrolysis products with the pyrolysis temperature and amino acid concentration were also investigated. PMID:21993510

Choi, Sung-Seen; Ko, Ji-Eun

2011-11-18

245

Experimental investigation of pyrolysis process of woody biomass mixture  

Science.gov (United States)

This paper describes an experimental investigation of pyrolysis of woody biomass mixture. The mixture consists of oak, beech, fir, cherry, walnut and linden wood chips with equal mass fractions. During the experiment, the sample mass inside the reactor was 10 g with a particle diameter of 5-10 mm. The sample in the reactor was heated in the temperature range of 24-650C. Average sample heating rates in the reactor were 21, 30 and 54 C/min. The sample mass before, during and after pyrolysis was determined using a digital scale. Experimental results of the sample mass change indicate that the highest yield of pyrolytic gas was achieved at the temperature slightly above 650C and ranged from 77 to 85%, while char yield ranged from 15 to 23%. Heating rate has significant influence on the pyrolytic gas and char yields. It was determined that higher pyrolysis temperatures and heating rates induce higher yields of pyrolytic gas, while the char mass reduces. Condensation of pyrolytic gas at the end of the pyrolysis process at 650C produced 2.4-2.72 g of liquid phase. The results obtained represent a starting basis for determining material and heat balance of pyrolysis process as well as woody biomass pyrolysis equipment.

Kosani?, Tijana R.; ?erani?, Mirjana B.; ?uri?, Slavko N.; Grkovi?, Vojin R.; Miloti?, Milan M.; Brankov, Saa D.

2014-06-01

246

Pyrolysis of waste plastic crusts of televisions.  

Science.gov (United States)

The disposal of waste plastic crusts of televisions is an issue that is gaining increasing interest around the world. In this investigation, the pyrolysis and catalytic cracking of the waste television crusts mainly composed of acrylonitrile--butadiene-styrene copolymer was studied. Thermogravimetric analysis was used for initial characterization of the pyrolysis of the waste plastic, but most of the investigations were carried out using a 600 mL tubing reactor. Effects of temperature, reaction time and catalyst on the pyrolysis of the waste television crusts were investigated. The results showed that the oil yield increased with increasing temperature or with prolongation of reaction time. With increasing temperature, the generating percentage of gasoline and diesel oil increased, but the heavy oil yield decreased. Zinc oxide, iron oxide and fluid catalytic cracking catalyst (FCC catalyst) were employed to perform a series of experiments. It was demonstrated that the liquid product was markedly improved and the reaction temperature decreased 100 degrees C when FCC was used. The composition ofpyrolysis oils was analysed using gas chromatography-mass spectrometry, and they contained 36.49% styrene, 19.72% benzenebutanenitrile, 12.1% alpha-methylstyrene and 9.69% dimethylbenzene. PMID:23240191

Liu, Xinmin; Wang, Zhen; Xu, Dongyan; Guo, Qingjie

2012-09-01

247

Volatile Analysis by Pyrolysis of Regolith for Planetary Resource Exploration  

Science.gov (United States)

The extraction and identification of volatile resources that could be utilized by humans including water, oxygen, noble gases, and hydrocarbons on the Moon, Mars, and small planetary bodies will be critical for future long-term human exploration of these objects. Vacuum pyrolysis at elevated temperatures has been shown to be an efficient way to release volatiles trapped inside solid samples. In order to maximize the extraction of volatiles, including oxygen and noble gases from the breakdown of minerals, a pyrolysis temperature of 1400 C or higher is required, which greatly exceeds the maximum temperatures of current state-of-the-art flight pyrolysis instruments. Here we report on the recent optimization and field testing results of a high temperature pyrolysis oven and sample manipulation system coupled to a mass spectrometer instrument called Volatile Analysis by Pyrolysis of Regolith (VAPoR). VAPoR is capable of heating solid samples under vacuum to temperatures above 1300 C and determining the composition of volatiles released as a function of temperature.

Glavin, Daniel P.; Malespin, Charles; ten Kate, Inge L.; Getty, Stephanie A.; Holmes, Vincent E.; Mumm, Erik; Franz, Heather B.; Noreiga, Marvin; Dobson, Nick; Southard, Adrian E.; Feng, Steven H.; Kotecki, Carl A.; Dworkin, Jason P.; Swindle, Timothy D.; Bleacher, Jacob E.; Rice, James W.; Mahaffy, Paul R.

2012-01-01

248

Effect of Operating Conditions on Product Distributions and Bio-oil Ageing in Biomass Pyrolysis  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Alternatives to petroleum-derived fuels are receiving significant interest in order to reduce dependence on finite resources of fossil fuels and to lower fossil-derived CO2 emissions. The present study addresses the production of bio-oil from biomass pyrolysis, one of the potential renewable substitutes to petroleum-derived fuels. The first objective of this work was to investigate the effect of pyrolysis operating parameters, i.e. temperature, heating rate and pyrolysis time, ...

Somrang, Yatika

2012-01-01

249

Biomass pyrolysis processes: performance parameters and their influence on biochar system benefits  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This study focuses on performance of biomass pyrolysis processes for use in biochar systems. Objectives are to understand the range of control of such processes and how this affects potential benefits of pyrolysis biochar systems, in particular for climate change mitigation. Slow, intermediate and fast pyrolysis processes are reviewed. Product yield distributions change depending on feedstock composition and preparation, control of temperature and material flows. These allow s...

Brownsort, Peter A.

2009-01-01

250

Kinetic Study of the Pyrolysis of Waste Printed Circuit Boards Subject to Conventional and Microwave Heating  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This paper describes a kinetic study of the decomposition of waste printed circuit boards (WPCB) under conventional and microwave-induced pyrolysis conditions. We discuss the heating rates and the influence of the pyrolysis on the thermal decomposition kinetics of WPCB. We find that the thermal degradation of WPCB in a controlled conventional thermogravimetric analyzer (TGA) occurred in the temperature range of 300 C600 C, where the main pyrolysis of organic matter takes place along wi...

Jing Sun; Wenlong Wang; Zhen Liu; Qingluan Ma; Chao Zhao; Chunyuan Ma

2012-01-01

251

Flash pyrolysis of Green River shale: Technical note  

Energy Technology Data Exchange (ETDEWEB)

This study was part of a multireactor project on rapid shale pyrolysis. The work presented here is a progress report on a major phase of the flash lamp work. A flash lamp reactor was used to study rapid kerogen and shale retorting mechanisms, to evaluate the potential oil yield enhancement due to rapid heating, and to fill in gaps in the data on the composition and distribution of the product from rapid pyrolysis. Two predictive models were developed to evaluate the time-temperature profiles during flash pyrolysis, each with different degrees of complexity and transportability. Experiments were conducted to verify and refine the models in order to obtain better accuracy. Statistically designed flash pyrolysis experiments were conducted in conjunction with model calculations to assess the response of a Green River oil shale under different experimental conditions. 16 refs., 27 figs., 4 tabs.

Shadle, L.J.; Hobbs, G.R.; Rosencrans, R.D.; Seshadri, K.S.; Jaganathan, J.; Galloway, D.C.; Wang, Y.H.; Shen, M.S.; Lui, A.P.; Grimplin, J.M.

1987-10-01

252

Distribution of sulphur into products from waste tire pyrolysis  

International Nuclear Information System (INIS)

Tire pyrolysis is getting growing attention as an effective waste tire disposal method in comparison to environmentally less friendly methods like dumping or incineration. But the scrap tire sulphur content can be a potential obstacle to scrap tire utilization as a fuel. In this paper the distribution of sulphur into tire pyrolysis yields, solid (char) and liquid (tar), was investigated. The pyrolysis experiments were carried out under different conditions to determine the partitioning of sulphur into pyrolysis products. The influence of different temperatures and reaction times was investigated in a laboratory flow reactor under nitrogen atmosphere. Solid and liquid residues were collected and analyzed by elemental analysis. The sulphur content in residual char and tar was determined using an elemental analyzer and the sulphur forms in tar were characterized by the X-ray photoelectron spectroscopy (XPS). (Authors)

2012-05-15

253

Pyrolysis and gasification behavior of black liquor under pressurized conditions  

Energy Technology Data Exchange (ETDEWEB)

The purpose of this study has been to enhance the understanding of the processes involved in pressurized black liquor gasification. Gasification is known to occur in three stages: drying, pyrolysis and char gasification. The work presented here focuses on the pyrolysis and gasification stages. Experiments were carried out primarily in two laboratory-scale reactors. A pressurized grid heater was used to study black liquor pyrolysis under pressurized conditions. Char yields and the fate of elements in the liquor, as well as the degree of liquor swelling, were measured in this device. A pressurized thermogravimetric reactor was used to measure the rate of the char gasification process under different temperatures and pressures and in various gas atmospheres. Pyrolysis experiments were also carried out in this device, and data on swelling behavior, char yields and component release were obtained 317 refs.

Whitty, K.

1997-11-01

254

Liquid fuel from fast pyrolysis of oil palm solid wastes  

Energy Technology Data Exchange (ETDEWEB)

An investigation was conducted on the potential of producing liquid fuel from oil palm solid waste, particularly the palm fruit shell, by fast pyrolysis. For this purpose, a continuous fluidized bed fast pyrolysis system has been constructed. Fast pyrolysis was performed by feeding oil palm solid waste directly into the bubbling hot sand bed at a temperature ranging from 400 to 600 degrees centigrade in an inert atmosphere. The condensed liquid product was analysed for its properties as potential fuel and compared to petroleum fuel. The fuel characteristics compared were the physical properties, heating value, elemental analysis and chemical composition. The influence of some of the process conditions on the relative proportions of the liquid product and its properties and characteristics are presented. The results show the high potential of fast pyrolysis of oil palm solid waste particularly palm shell as an attractive source of a renewable energy in the form of liquid fuel. (author). 2 tabs., 4 figs., 7 refs.

Ani, F.N.; Zailani, R. [Technology Univ. of Malaysia, Kuala Lumpur (Malaysia)

1995-12-31

255

Silane-Pyrolysis Reactor With Nonuniform Heating  

Science.gov (United States)

Improved reactor serves as last stage in system processing metallurgical-grade silicon feedstock into silicon powder of ultrahigh purity. Silane pyrolized to silicon powder and hydrogen gas via homogeneous decomposition reaction in free space. Features set of individually adjustable electrical heaters and purge flow of hydrogen to improve control of pyrolysis conditions. Power supplied to each heater set in conjunction with flow in reactor to obtain desired distribution of temperature as function of position along reactor.

Iya, Sridhar K.

1991-01-01

256

Pyrolysis process and apparatus  

Science.gov (United States)

This invention discloses a process and apparatus for pyrolyzing particulate coal by heating with a particulate solid heating media in a transport reactor. The invention tends to dampen fluctuations in the flow of heating media upstream of the pyrolysis zone, and by so doing forms a substantially continuous and substantially uniform annular column of heating media flowing downwardly along the inside diameter of the reactor. The invention is particularly useful for bituminous or agglomerative type coals.

Lee, Chang-Kuei (Sewell, NJ)

1983-01-01

257

Effect of pyrolysis intensity on the reactivity of coal char  

Energy Technology Data Exchange (ETDEWEB)

The effect of pyrolysis conditions on char combustion reactivity was studied in this paper. The char samples were prepared in a N{sub 2} atmosphere from the vitrinite constituents of two bituminous coals (YX and JJ) and their demineralized samples at different temperatures (800-1200{sup o}C) and for different residence times. The effect of pyrolysis intensity on the carbon microstructure in the resulting char was characterized by the X-ray diffraction (XRD) technique. The reactivity of the char samples prepared under different pyrolysis conditions was measured by isothermal thermogravimetric analysis methods in an air atmosphere. The results show that the reactivity of the coal char decreases with increasing pyrolysis intensity and, when the pyrolysis temperature is high enough, the reactivity of the chars prepared from two coals and their demineralized samples tend to be the same. With increasing pyrolysis intensity, the growth of the carbon microstructure, accompanied by diminishing catalytic capability of minerals, results in the decrease in char reactivity. 43 refs., 12 figs., 3 tabs.

Shou-Yu Zhang; Jun-Fu Lu; Jian-Sheng Zhang; Guang-Xi Yue [University of Shanghai for Science and Technology, Shanghai (China). Department of Power Engineering

2008-09-15

258

Pyrolysis of polystyrene - polyphenylene oxide to recover styrene and useful products  

Energy Technology Data Exchange (ETDEWEB)

A process of using fast pyrolysis in a carrier gas to convert a polystyrene and polyphenylene oxide plastic waste to a given polystyrene and polyphenylene oxide prior to pyrolysis of other plastic components therein comprising: selecting a first temperature range to cause pyrolysis of given polystyrene and polyphenylene oxide and its high value monomeric constituent prior to a temperature range that causes pyrolysis of other plastic components; selecting a catalyst and a support and treating the feed stream with the catalyst to affect acid or base catalyzed reaction pathways to maximize yield or enhance separation of high value monomeric constituent of styrene from polystyrene and polyphenylene oxide in the first temperature range; differentially heating the feed stream at a heat rate within the first temperature range to provide differential pyrolysis for selective recovery of the high value monomeric constituent of styrene from polystyrene and polyphenylene oxide prior to pyrolysis of other plastic components; separating the high value monomer constituent of styrene; selecting a second higher temperature range to cause pyrolysis to a different derived high value product of polyphenylene oxide from the plastic waste and differentially heating the feed stream at the higher temperature range to cause pyrolysis of the plastic into a polyphenylene oxide derived product; and separating the different derived high value polyphenylene oxide product.

Evans, Robert J. (Lakewood, CO); Chum, Helena L. (Arvada, CO)

1995-01-01

259

Investigating the potential for a self-sustaining slow pyrolysis system under varying operating conditions.  

Science.gov (United States)

This work aimed to investigate the impact of highest treatment temperature (HTT), heating rate, carrier gas flow rate and feedstock on the composition and energy content of pyrolysis gas to assess whether a self-sustained system could be achieved through the combustion of the gas fraction alone, leaving other co-products available for alternative high-value uses. Calculations based on gas composition showed that the pyrolysis process could be sustained by the energy contained within the pyrolysis gases alone. The lower energy limit (6% biomass higher heating value (HHV)) was surpassed by pyrolysis at ?450C while only a HTT of 650C consistently met the upper energy limit (15% biomass HHV). These findings fill an important gap in literature related to the energy balance of the pyrolysis systems for biochar production, and show that, at least from an energy balance perspective; self-sustained slow pyrolysis for co-production of biochar and liquid products is feasible. PMID:24747394

Crombie, Kyle; Maek, Ond?ej

2014-06-01

260

A new pyrolysis technique using a diamond anvil cell: in situ visualization of kerogen transformation  

Energy Technology Data Exchange (ETDEWEB)

A pyrolysis technique has been developed to study hydrocarbon source rock potential by in situ visualization of kerogen transformation in a diamond anvil cell under a microscope (white and UV-light) using a CCD video monitoring system. The technique unables one to observe directly the processes and timing (or temperature) of kerogen transformation during pyrolysis in open or closed systems (either anhydrous or hydrous). It has been used to study a Green River kerogen and a lignite sample at heating rates similar to Rock-Eval pyrolysis under several pyrolysis conditions.

Huang, W.L. [Exxon Production Research Company, Houston, TX (United States)

1996-01-01

 
 
 
 
261

Controlled catalystic and thermal sequential pyrolysis and hydrolysis of polycarbonate and plastic waste to recover monomers  

Energy Technology Data Exchange (ETDEWEB)

A process of using fast pyrolysis to convert a plastic waste feed stream containing polycarbonate and ABS to high value monomeric constituents prior to pyrolysis of other plastic components therein comprising: selecting a first temperature program range to cause pyrolysis of a given polymer to its high value monomeric constituents prior to a temperature range that causes pyrolysis of other plastic components; selecting an acid or base catalysts and an oxide or carbonate support for treating the feed stream to affect acid or base catalyzed reaction pathways to maximize yield or enhance separation of the high value monomeric constituents of polycarbonate and ABS in the first temperature program range; differentially heating the feed stream at a heat rate within the first temperature program range to provide differential pyrolysis for selective recovery of optimum quantities of the high value monomeric constituents prior to pyrolysis or other plastic components; separating the high value monomeric constituents from the polycarbonate to cause pyrolysis to a different high value monomeric constituent of the plastic waste and differentially heating the feed stream at the second higher temperature program range to cause pyrolysis of different high value monomeric constituents; and separating the different high value monomeric constituents.

Evans, Robert J. (Lakewood, CO); Chum, Helena L. (Arvada, CO)

1994-01-01

262

Hydrogen-rich gaseous products from tea waste by pyrolysis  

Energy Technology Data Exchange (ETDEWEB)

Hydrogen from solid wastes is produced by pyrolysis. In this study, tea factory waste samples were subjected to direct and catalytic pyrolysis to obtain hydrogen-rich gaseous products at desired temperatures. The samples, both untreated and impregnated with the catalyst, were pyrolyzed at temperatures of 775, 850, 925, 975, and 1025 K. The total volume and the yield of gas from both forms of pyrolysis increase with increasing temperature. The largest hydrogen-rich gas yield obtained from tea waste, using about 13% ZnCl{sub 2} as a catalyst at about 1025 K temperature, is 60.3%, respectively. In general, in the pyrolysis of tea waste, the yield of hydrogen-rich gaseous product increases with ZnCl{sub 2} catalyst, but the yield of pyrolytic gas decreases in spite of increasing the yield of charcoal and liquid products. The catalytic effect of Na{sub 2}CO{sub 3} was greater than that of K{sub 2}CO{sub 3} for pyrolysis of the tea waste. (author)

Caglar, A.; Demirbas, A.

2001-09-01

263

Deoxygenation of hydroquinones as a general route to norbornane-fused aromatic systems: an entry into substituted and functionalized dimethano- and methanoanthracenes.  

Science.gov (United States)

A high-yielding route to substituted and functionalized dimethanoanthracenes by the Pd-catalyzed deoxyenation of the corresponding hydroquinone precursors is described. Attempts were made to deoxygenate the 9,10-dimesylate, ditosylate, and ditriflate derivatives of anti-dimethanoanthracene 1a, and it was found that under the studied conditions only the ditriflate 8a gave the corresponding deoxygenated aromatic scaffold. Optimization of the reaction conditions identified the Pd(OAc)(2)/dppf tandem as a suitable catalytic system for this transformation. The presented strategy was further extended to a novel and efficient synthetic route to methanoanthracenes employing a one-pot Pd-catalyzed deoxygenation/hydrogenation sequence. PMID:22136284

Ganji, Prasad; Ibrahim, Hasim

2012-01-01

264

Pyrolysis of low rank Canadian coals  

Energy Technology Data Exchange (ETDEWEB)

A bench scale fluidized bed reactor with a continuous feed rate of 15-30 g/h has been developed to study the flash pyrolysis of coal at atmospheric pressure. The pyrolysis behaviour of four low rank Canadian coals has been investigated at 0.44 s apparent vapour residence time over a temperature range of 500-800/sup 0/C. Conditions for maximum liquid yield have been determined for each of the coals. Material balances on all products were generally satisfactory. Variation of vapour residence time from 0.2 to 1.4 s showed that the maximum liquid yield was obtained at the minimum residence time. Use of different particle sizes indicated that an optimum size probably exists for a given set of reaction conditions. Use of a hydrogenation catalyst did not increase liquid yields and the nature of the reaction atmosphere had only a minor effect on liquid yields. The H/C ratio of both the pyrolysis oil and the char decreased with increasing temperature. The maximum tar yields from lignite can be approximately correlated with the atomic H/C ratio of the parent coals. 12 tabs., 20 figs., 18 refs.

Scott, D.S.; Piskorz, J.; Fouda, S.

1986-06-01

265

Pyrolysis oil as diesel fuel  

Energy Technology Data Exchange (ETDEWEB)

Wood waste pyrolysis oil is an attractive fuel alternative for diesel engine operation. The main benefit is the sustainability of the fuel. No fossil reserves are consumed. The fact that wood waste pyrolysis oil does not contribute to CO{sub 2} emissions is of utmost importance. This means that power plants utilising pyrolysis oil do not cause additional global warming. Equally important is the reduced sulphur emissions that this fuel alternative implies. The sulphur content of pyrolysis oil is extremely low. The high water content and low heating value are also expected to result in very low NO{sub x} emissions. Utilisation of wood waste pyrolysis oil in diesel engines, however, involves a lot of challenges and problems to be solved. The low heating value requires a new injection system with high capacity. The corrosive characteristics of the fluid also underline the need for new injection equipment materials. Wood waste pyrolysis oil contains solid particles which can clog filters and cause abrasive wear. Wood waste pyrolysis oil has proven to have extremely bad ignition properties. The development of a reliable injection system which is able to cope with such a fuel involves a lot of optimisation tests, redesign and innovative solutions. Successful single-cylinder tests have already been performed and they have verified that diesel operation on wood pyrolysis oil is technically possible. (orig.)

Gros, S. [Wartsila Diesel International Ltd., Vaasa (Finland). Diesel Technology

1996-12-31

266

Spray pyrolysis and thermal processing  

Energy Technology Data Exchange (ETDEWEB)

Spray pyrolysis and thermal processing of superconducting wire are outlined. Topics discussed include: spray pyrolysis, 2-zone processing, PBSCCO precursor on LaAlO{sub 3}, GE verification study, verification results, physical properties of lattice - matched metal oxide materials, and thick film processing, future plans, major results, and program plans for FY95 are summarized.

Parilla, P.A. [National Renewable Energy Lab., Golden, CO (United States)

1994-07-29

267

Microwave Heating Applied to Pyrolysis  

Digital Repository Infrastructure Vision for European Research (DRIVER)

the MW pyrolysis as an original thermochemical process of materials is presented. This chapter comprises a general overview of the thermochemical and quantifying aspects of the pyrolysis process, including current application togethe with a compilation of the most frequently used materials

Ferna?ndez, Yolanda; Arenillas, Ana; Mene?ndez, J. A?ngel

2011-01-01

268

Pyrolysis product distribution of waste newspaper in MSW  

Energy Technology Data Exchange (ETDEWEB)

Waste newspaper, one of the principal waste papers in Taiwan, was pyrolyzed with a thermogravimetric analysis (TGA) reaction system. The pyrolysis experiments were carried out in nitrogen environment at a constant heating rate of 5 Kmin{sup -1}. The pyrolysis products and the residues were collected and analyzed by gas chromatography and elemental analyzer, respectively. The major products investigated included non-hydrocarbons (H{sub 2}, CO, CO{sub 2}, and H{sub 2}O) and hydrocarbons (C{sub 1-3}, C{sub 4}, C{sub 5}, C{sub 6}, 1-ring, C{sub 10-12}, levoglucosan, C{sub 13-15}, and C{sub 16-18}). The cumulated masses and the instantaneous concentrations of pyrolysis products were obtained under the experimental conditions. The estimation of the mass of tar, yielded at various pyrolysis temperatures, was also made. The results of this study might be useful for the design of pyrolysis process as well as for determining the pyrolysis mechanisms of the newspaper.

Wu, Chao-Hsiung [Department of Environmental Engineering, Da-Yeh University, Chang-Hwa 515 (Taiwan); Chang, Ching-Yuan [Graduate Institute of Environmental Engineering, National Taiwan University, Taipei 106 (Taiwan); Tseng, Chao-Heng [Department of Civil Engineering, National Taipei University of Technology, Taipei 106 (Taiwan); Lin, Jyh-Ping [Department of Environmental Engineering, Lan-Yang Institute of Technology, I-Lan 261 (Taiwan)

2003-03-01

269

Kinetics of scrap tyre pyrolysis under vacuum conditions.  

Science.gov (United States)

Scrap tyre pyrolysis under vacuum is attractive because it allows easier product condensation and control of composition (gas, liquid and solid). With the aim of determining the effect of vacuum on the pyrolysis kinetics, a study has been carried out in thermobalance. Two data analysis methods have been used in the kinetic study: (i) the treatment of experimental data of weight loss and (ii) the deconvolution of DTG (differential thermogravimetry) curve. The former allows for distinguishing the pyrolysis of the three main components (volatile components, natural rubber and styrene-butadiene rubber) according to three successive steps. The latter method identifies the kinetics for the pyrolysis of individual components by means of DTG curve deconvolution. The effect of vacuum in the process is significant. The values of activation energy for the pyrolysis of individual components of easier devolatilization (volatiles and NR) are lower for pyrolysis under vacuum with a reduction of 12K in the reaction starting temperature. The kinetic constant at 503K for devolatilization of volatile additives at 0.25atm is 1.7 times higher than that at 1atm, and that corresponding to styrene-butadiene rubber at 723K is 2.8 times higher. Vacuum enhances the volatilization and internal diffusion of products in the pyrolysis process, which contributes to attenuating the secondary reactions of the repolymerization and carbonization of these products on the surface of the char (carbon black). The higher quality of carbon black is interesting for process viability. The large-scale implementation of this process in continuous mode requires a comparison to be made between the economic advantages of using a vacuum and the energy costs, which will be lower when the technologies used for pyrolysis require a lower ratio between reactor volume and scrap tyre flow rate. PMID:19589669

Lopez, Gartzen; Aguado, Roberto; Olazar, Martn; Arabiourrutia, Miriam; Bilbao, Javier

2009-10-01

270

Fast pyrolysis (ultrapyrolysis) of cellulose  

Energy Technology Data Exchange (ETDEWEB)

A fast pyrolysis process, termed ultrapyrolysis, has been developed at the Univ. of Western Ontario in order to exploit the high heating rates, short residence times, high temperatures and rapid quenching, which are required to produce valuable non-equilibrium intermediates (i.e. ethylene and acetylene) from finely divided biomass. Hot solids (Thermofor) are used to carry and transfer heat to the biomass particles in a very turbulent vortical contactor (Thermovortactor). This turbulence creates an ideal environment for fast thorough mixing and extremely rapid heat transfer. Cold solids (Cryofor) are then used to quickly quench the products. Trials with cellulose were conducted at temperatures between 750 and 900/sup 0/C and residence times between 250 and 450 ms. Ethylene yields, expressed as a mass fraction of the product gas, varied from 6.8 to 8.2% for temperatures ranging from 750 to 900/sup 0/C, respectively. The total hydrocarbon yield, also expressed as a mass fraction of the product gas, was 18.8% at 900/sup 0/C. The conversion of cellulose to a permanent non-condensible gaseous product was estimated to be 98% by mass at 900/sup 0/C. 6 references, 2 figures, 3 tables.

Graham, R.G.; Mok, L.K.; Bergougnou, M.A.; De Lasa, H.I.; Freel, B.A.

1984-09-01

271

Pyrolysis of Softwood Carbohydrates in a Fluidized Bed Reactor  

Science.gov (United States)

In the present work pyrolysis of pure pine wood and softwood carbohydrates, namely cellulose and galactoglucomannan (the major hemicellulose in coniferous wood), was conducted in a batch mode operated fluidized bed reactor. Temperature ramping (5 C/min) was applied to the heating until a reactor temperature of 460 C was reached. Thereafter the temperature was kept until the release of non-condensable gases stopped. The different raw materials gave significantly different bio-oils. Levoglucosan was the dominant product in the cellulose pyrolysis oil. Acetic acid was found in the highest concentrations in both the galactoglucomannan and in the pine wood pyrolysis oils. Acetic acid is most likely formed by removal of O-acetyl groups from mannose units present in GGM structure.

Aho, Atte; Kumar, Narendra; Eranen, Kari; Holmbom, Bjarne; Hupa, Mikko; Salmi, Tapio; Murzin, Dmitry Yu.

2008-01-01

272

Thermal response of heat-resistant layer with pyrolysis  

Directory of Open Access Journals (Sweden)

Full Text Available A model is developed for analyzing the thermal response of the heat-resistant layer composed of high silica fiber reinforced phenolic matrix composites(SiO2/P and aluminum, in which pyrolysis and phase transitions are exsited, such as melt, vaporization and sublimation. Based on this model, the thermal response of the heat-resistant layer with different SiO2/P thickness is calculated under a heat flux by using FORTRAN codes. As indicated in the results, the slope of temperature gets a sudden decline at the pyrolysis interface, which is due to the latent heat of pyrolysis; the thickness of heat-resistant layer has little influence on the heating-surface temperature, however, the back temperature may increase with the decreasing thickness; and the thermal conductivity of carbonized layer is very important to thermal response.

Huang Haiming

2012-01-01

273

Pyrolysis of Softwood Carbohydrates in a Fluidized Bed Reactor  

Directory of Open Access Journals (Sweden)

Full Text Available In the present work pyrolysis of pure pine wood and softwood carbohydrates, namely cellulose and galactoglucomannan (the major hemicellulose in coniferous wood, was conducted in a batch mode operated fluidized bed reactor. Temperature ramping (5°C/min was applied to the heating until a reactor temperature of 460 °C was reached. Thereafter the temperature was kept until the release of non-condensable gases stopped. The different raw materials gave significantly different bio-oils. Levoglucosan was the dominant product in the cellulose pyrolysis oil. Acetic acid was found in the highest concentrations in both the galactoglucomannan and in the pine wood pyrolysis oils. Acetic acid is most likely formed by removal of O-acetyl groups from mannose units present in GGM structure.

Dmitry Yu. Murzin

2008-09-01

274

Pyrolysis of methane by microwaves. Pt. 1  

International Nuclear Information System (INIS)

The pyrolysis of methane and mixtures of argon-methane by microwaves (2,450 MHz) was investigated. The microwave plasma diagnostic study was performed using electrical probes, namely, the double floating probe technique. Parameters such as electric field strength and current densities were measured and from their relationship the electron temperature, electric conductivity, electron and ion densities were evaluated as function of gas pressure, microwave power input and distance of the probe from the microwave cavity. Various spectroscopic techniques were used for the measurement of temperatures in the microwave plasma; the 'reversal temperature' by measuring the intensities of the electronic vibrational bands of CN and OH molecules and 'rotational temperature' from the measured intensities of rotational OH lines. The 'rotational' as well as the 'reversal temperature' were found to be identical and this temperature was assumed to be the temperature of the gas in the microwave plasma. Energy balance calculation, based upon the electrical energy input and thermal losses, were performed in order to determine if steady state conditions existed in the microwave plasma. Emission and absorption spectroscopy were used for determining the active species formed in the pyrolysis of methane and also of mixtures of CH_4-Ar, by the microwave plasma. (orig.)

1975-01-01

275

RATES AND EQUILIBRIA OF DEVOLATILIZATION AND TRACE ELEMENT EVOLUTION IN COAL PYROLYSIS  

Science.gov (United States)

The report gives results of using a laminar-flow furnace to study the kinetics of devolatilization and evolution of S, As, Pb, and Hg in the pyrolysis of pulverized coal in nitrogen. Variables included pyrolysis time, reactor temperature, and coal type. Devolatilization rates and...

276

Preparation of YBCO superconducting films by spray pyrolysis method  

International Nuclear Information System (INIS)

The methodology for the preparation of YBCO superconducting films on Zr"2"O(Y) substrates by spray pyrolysis method is reported. The transition temperature of these films is superior than the boiling temperature of liquid "2"N. Other critical parameters are similar to those reported by other authors using the same technique

1994-01-01

277

Extreme warming, photic zone euxinia and sea level rise during the Paleocene/Eocene Thermal Maximum on the Gulf of Mexico Coastal Plain; connecting marginal marine biotic signals, nutrient cycling and ocean deoxygenation  

Science.gov (United States)

The Paleocene/Eocene Thermal Maximum (PETM, ~56 Ma) was a ~200 kyr episode of global warming, associated with massive injections of 13C-depleted carbon into the ocean-atmosphere system. Although climate change during the PETM is relatively well constrained, effects on marine oxygen and nutrient cycling remain largely unclear. We identify the PETM in a sediment core from the US margin of the Gulf of Mexico. Biomarker-based paleotemperature proxies (MBT/CBT and TEX86) indicate that continental air and sea surface temperatures warmed from 27-29 C to ~35 C, although variations in the relative abundances of terrestrial and marine biomarkers may have influenced the record. Vegetation changes as recorded from pollen assemblages supports profound warming. Lithology, relative abundances of terrestrial vs. marine palynomorphs as well as dinoflagellate cyst and biomarker assemblages indicate sea level rise during the PETM, consistent with previously recognized eustatic rise. The recognition of a maximum flooding surface during the PETM changes regional sequence stratigraphic interpretations, which allows us to exclude the previously posed hypothesis that a nearby fossil found in PETM-deposits represents the first North American primate. Within the PETM we record the biomarker isorenieratane, diagnostic of euxinic photic zone conditions. A global data compilation indicates that deoxygenation occurred in large regions of the global ocean in response to warming, hydrological change, and carbon cycle feedbacks, particularly along continental margins, analogous to modern trends. Seafloor deoxygenation and widespread anoxia likely caused phosphorus regeneration from suboxic and anoxic sediments. We argue that this fuelled shelf eutrophication, as widely recorded from microfossil studies, increasing organic carbon burial along continental margins as a negative feedback to carbon input and global warming. If properly quantified with future work, the PETM offers the opportunity to assess the biogeochemical effects of enhanced phosphorus regeneration, as well as the time-scales on which this feedback operates in view of modern and future ocean deoxygenation.

Sluijs, A.; van Roij, L.; Harrington, G. J.; Schouten, S.; Sessa, J. A.; LeVay, L. J.; Reichart, G.-J.; Slomp, C. P.

2013-12-01

278

Influence of a deoxygenation process on the magnetic diagrm of iron doped YBa 2Cu 3O y phases: a neutron diffraction study  

Science.gov (United States)

Neutron powder diffraction measurements (NPD) and Mssbauer spectroscopy (MS) have been performed to determine the magnetic phase diagram of the YBa 2(Cu 1- xFe x) 3O y system with 0 ? x ? 0.16 and an oxygen content y close to 6.3. These phases were deoxygenated from the initial oxygen-rich state ( y ? 7), by a low temperature process. This thermal treatment leaves the iron distribution identical to the one of the original oxygenated compound, whereas the usual high temperature method leads to a modification of the iron distribution. The distribution of iron on the two copper sites, Cu(1) and Cu(2), was carefully checked by both methods. The thermal dependence of the mean magnetic moments on the Cu(1) and Cu(2) sites was determined from Rietveld refinements. For x > 0.04, a collinear phase (AF?2) is observed with a doubling of the cell along the c axis and a ferromagnetic coupling between Cu(1) and Cu(2) sites. At lower iron content, several transitions are observed as the temperature decreases, from a paramagnetic to a collinear structure without any moment on the Cu(1) site, then to a canted structure and at low temperature the AF?2 structure is stabilized.

Suard, E.; Mirebeau, I.; Caignaert, V.; Imbert, P.; Balagurov, A. M.

1997-02-01

279

Heterogeneity in cellulose pyrolysis indicated from the pyrolysis in sulfolane  

Energy Technology Data Exchange (ETDEWEB)

In sulfolane (tetramethylene sulfone), which is a good solvent for the primary product, levoglucosan, cellulose is pyrolyzed completely into soluble products without forming any char. Residues during pyrolysis in sulfolane at 200, 240 and 330{sup o}C were obtained always as colorless non-carbonized substances. From the change in the crystallinity and crystallite size as compared with the ordinary pyrolysis, a heterogeneous mechanism is indicated for cellulose pyrolysis, starting from a molecule which is less stabilized due to lack of some intermolecular interactions. (author)

Kawamoto, H.; Saka, S. [Graduate School of Energy Science, Kyoto University, Yoshida-honmachi, Sakyo-ku, Kyoto 606-8501 (Japan)

2006-06-01

280

Resource recovery by pyrolysis  

Energy Technology Data Exchange (ETDEWEB)

While by means of the conventional pyrolysis technologies it was possible to treat one specific waste only, it is the aim of this project to develop a technology which enables to process a great number of hydrocarbonaceous industrial wastes, even in mixture. The technology was developed in both, a laboratory and in a testing plant with a capacity of 200 kg/h and within 3.000 operating hours successfully proved. Residues from car shredding plants, plastics, used cables and acid tars were pyrolysed separately as well as in a mixture. The pyrolysis products thus gained are upgraded in a succeeding stage to meet market demands or for use in a secondary refinery. The calculation of profitability for a large plant proves that a balanced operating result can be reached. The aim of continuous developments is to secure the scaling up by erection of a 2 t/h pilot plant and the application of the process for more types of waste with a long-term availability. Particularly in industrial areas this technology will play an important part with regard to waste disposal as well as resource recovery.

Andreas, B.; Birckenstaedt, W.; Bracker, G.P.; Collin, G.; Grigoleit, G.; Zander, M.

1981-02-01

 
 
 
 
281

Controlled catalytic and thermal sequential pyrolysis and hydrolysis of phenolic resin containing waste streams to sequentially recover monomers and chemicals  

Energy Technology Data Exchange (ETDEWEB)

A process of using fast pyrolysis in a carrier gas to convert a waste phenolic resin containing feedstreams in a manner such that pyrolysis of said resins and a given high value monomeric constituent occurs prior to pyrolyses of the resins in other monomeric components therein comprising: selecting a first temperature program range to cause pyrolysis of said resin and a given high value monomeric constituent prior to a temperature range that causes pyrolysis of other monomeric components; selecting, if desired, a catalyst and a support and treating said feedstreams with said catalyst to effect acid or basic catalyzed reaction pathways to maximize yield or enhance separation of said high value monomeric constituent in said first temperature program range to utilize reactive gases such as oxygen and steam in the pyrolysis process to drive the production of specific products; differentially heating said feedstreams at a heat rate within the first temperature program range to provide differential pyrolysis for selective recovery of optimum quantity of said high value monomeric constituent prior to pyrolysis of other monomeric components therein; separating said high value monomeric constituent; selecting a second higher temperature program range to cause pyrolysis of a different high value monomeric constituent of said phenolic resins waste and differentially heating said feedstreams at said higher temperature program range to cause pyrolysis of said different high value monomeric constituent; and separating said different high value monomeric constituent.

Chum, Helena L. (Arvada, CO); Evans, Robert J. (Lakewood, CO)

1992-01-01

282

Flash pyrolysis fuel oil: BIO-POK  

Energy Technology Data Exchange (ETDEWEB)

Flash pyrolysis oil from Ensyn Tech., Canada and Union Fenosa, Spain was combusted with simple pressure atomisation equipment commonly used with light fuel oils in intermediate size (0.1-1 MW) boilers. With a number of modifications to the combustion system, carbon monoxide (CO) and nitrous oxide (NO{sub x}) could be reduced to acceptable levels: CO < 30 ppm and NO{sub x} < 140 ppm. Particulate emissions which were initially very high (Bacharach 4-5) were reduced (Bach. 2-3) by system changes but are still higher than from light fuel oil (Bach. <1). The modifications to the combustion system were: acid resistant progressive cavity pump, higher oil preheat temperature and higher oil pressure than for light fuel oils, refractory section between burner and boiler warmed up to at least 800 deg C. In addition, it was necessary to store pyrolysis oil samples under inert conditions to prevent oxidation and to rinse nozzles with alcohol after shutdown to prevent coking. The complexity and cost of these system modifications are considered to be too great for current grades of flash pyrolysis oil to be sold as a light fuel oil replacement. Improvements to fuel quality will be necessary. The main improvements are lowering of viscosity and improving of stability

Gust, S. [Neste Oy, Porvoo (Finland)

1995-12-31

283

Pyrolysis and dehalogenation of plastics from waste electrical and electronic equipment (WEEE): a review.  

Science.gov (United States)

Plastics from waste electrical and electronic equipment (WEEE) have been an important environmental problem because these plastics commonly contain toxic halogenated flame retardants which may cause serious environmental pollution, especially the formation of carcinogenic substances polybrominated dibenzo dioxins/furans (PBDD/Fs), during treat process of these plastics. Pyrolysis has been proposed as a viable processing route for recycling the organic compounds in WEEE plastics into fuels and chemical feedstock. However, dehalogenation procedures are also necessary during treat process, because the oils collected in single pyrolysis process may contain numerous halogenated organic compounds, which would detrimentally impact the reuse of these pyrolysis oils. Currently, dehalogenation has become a significant topic in recycling of WEEE plastics by pyrolysis. In order to fulfill the better resource utilization of the WEEE plastics, the compositions, characteristics and dehalogenation methods during the pyrolysis recycling process of WEEE plastics were reviewed in this paper. Dehalogenation and the decomposition or pyrolysis of WEEE plastics can be carried out simultaneously or successively. It could be 'dehalogenating prior to pyrolysing plastics', 'performing dehalogenation and pyrolysis at the same time' or 'pyrolysing plastics first then upgrading pyrolysis oils'. The first strategy essentially is the two-stage pyrolysis with the release of halogen hydrides at low pyrolysis temperature region which is separate from the decomposition of polymer matrixes, thus obtaining halogenated free oil products. The second strategy is the most common method. Zeolite or other type of catalyst can be used in the pyrolysis process for removing organohalogens. The third strategy separate pyrolysis and dehalogenation of WEEE plastics, which can, to some degree, avoid the problem of oil value decline due to the use of catalyst, but obviously, this strategy may increase the cost of whole recycling process. PMID:22951495

Yang, Xiaoning; Sun, Lushi; Xiang, Jun; Hu, Song; Su, Sheng

2013-02-01

284

Macromolecular structure and coal pyrolysis  

Energy Technology Data Exchange (ETDEWEB)

A molecular level explanation for the dilatometric behaviour of an hvAb coal is sought. The macromolecular network structure of bituminous coals is described with emphasis on the non-covalent interactions responsible for coals being glasses at room temperature. The existence of a glass to rubber transition in coals at 600 K detected by both DSC and NMR is described and related to the initial softening and contraction observed in the dilatometer. The relationship between the phase transition and the pyrolysis chemistry simultaneously occurring is discussed and it is concluded that it is not known whether covalent bond cleavage is a cause of the phase transition. Covalent bond cleavages are not necessary for the transition to occur. In coking coals, thermally induced cross linking begins at temperatures well above Tg and after most tars have been released from the coal. The high degree of structural anisotropy of all coals is revealed by solvent swelling. Its role in coke forming processes is unknown. 23 refs., 1 fig.

Larsen, J.W.

1988-12-01

285

Slow Pyrolysis of Cassava Wastes for Biochar Production and Characterization  

Directory of Open Access Journals (Sweden)

Full Text Available Production of biochar from slow pyrolysis of biomass is a promising carbon negative procedure since it removes the net carbon dioxide in the atmosphere and produce recalcitrant carbon suitable for sequestration in soil. Biochar production can vary significantly with the pyrolysis parameter. This study investigated the impact of temperature and heating rate on the yield and properties of biochar derived from cassava plantations residues which are cassava stem (CS and cassava rhizome (CR. The pyrolysis temperatures ranged from 400C to 600C while the heating rate parameter was varied from 5C/min to 25C/min. The experiment was conducted using the lab scale slow pyrolysis system. The increment of temperature and heating rate of slow pyrolysis for both cassava wastes had raised the fixed carbon content of the biochar but decreased the biochar yield. More biochar was produced at lower temperature and lower heating rate. Temperature gave more influence on the biochar yield as compared to the heating rate parameter. The highest biochar yield of more than 35 mf wt. % can be obtained from both CS and CR at 400C and heating rate of 5C/min. From the proximate analysis, the results showed that cassava wastes contain high percentage of volatile matter which is more than 80 mf wt. %. Meanwhile, the biochar produced from cassava wastes contain high percentage of fixed carbon which is about 5?8 times higher than their raw samples. This suggested that, it is a good step to convert CS and CR into high carbon biochar via slow pyrolysis process that can substantially yield more biochar, up to 37 mf wt. % in this study. Since the fixed carbon content for both CS and CR biochar produced in any studied parameter were found to be more than 75 mf wt. %, it is suggested that biochar from cassava wastes is suitable for carbon sequestration.

Nurhidayah Mohamed Noor

2012-01-01

286

Progress in coal pyrolysis research  

Energy Technology Data Exchange (ETDEWEB)

This paper considers some of the recent progress in both the improved understanding and the identification of areas uncertainty with regard to coal pyrolysis, rates, and mechanisms. The paper addressed two questions: (1) what are the controlling chemical factors in coal pyrolysis? (2) what are the controlling physical factors in coal pyrolysis? The problem of answering the questions is that multiple chemical reactions occur whose results depend on how the reactants are bound in the coal macromolecular network. Species-selective transport of the reactants and products further complicate the interpretations. In what follows, we have tried to focus on topics where answers are needed or where significant new progress is being made.

Solomon, P.R.; Serio, M.A. [Advanced Fuel Research, Inc., East Hartford, CT (United States)

1994-12-31

287

The structure of a deoxygenated 400?kDa haemoglobin reveals ternary- and quaternary-structural changes of giant haemoglobins.  

Science.gov (United States)

The quaternary structures of invertebrate haemoglobins (Hbs) are quite different from those of vertebrate Hbs. The extracellular giant Hbs of molecular masses of about 400 and 3600?kDa are composed of a dome-shaped dodecameric subassembly which consists of four individual globin subunits. Several crystal structures of 400?kDa Hbs from annelids have been reported, including structures in oxygenated and partially unliganded states, but the structure of the fully deoxygenated state has not been reported. In the present study, crystal structures of V2Hb from the tube worm Lamellibrachia satsuma have been determined in both the fully oxygenated and deoxygenated states. A glycosylation site and novel metal-binding sites for divalent cations were clearly observed with no intersubunit interactions in V2Hb. A comparison of the oxygenated and the deoxygenated forms of V2Hb reveals that the ternary- and quaternary-structural changes occur in a manner that maintains the molecular D3 symmetry. These structures suggest that the mechanisms of quaternary-structural changes between the oxy and deoxy states for the giant Hbs are identical across species. PMID:25004960

Numoto, Nobutaka; Nakagawa, Taro; Ohara, Ryota; Hasegawa, Tomoyo; Kita, Akiko; Yoshida, Takao; Maruyama, Tadashi; Imai, Kiyohiro; Fukumori, Yoshihiro; Miki, Kunio

2014-07-01

288

Sex-related differences in muscle deoxygenation during ramp incremental exercise.  

Science.gov (United States)

Sex-specific differences in the temporal profiles of fractional O2 extraction during incremental cycling were examined using changes in near-infrared spectroscopy (NIRS)-derived muscle deoxygenated hemoglobin concentration (?[HHb]) and breath-by-breath pulmonary O2 uptake ( .VO2p ) measurements. Subject's (men: n=10; women: n=10) ?[HHb] data were normalized to 100% of the response, plotted as a function ( .VO2p, % .VO2p), power output (PO), and % PO, and fit with a piecewise double-linear regression model. The slope of the first segment of the double linear model was significantly greater in women compared to men when %?[HHb] was plotted as a function of .VO2p, % .VO2p and PO (p<0.05). Both sexes displayed a near-plateau in the %?[HHb] which occurred at an exercise intensity near the respiratory compensation point. Thus, young women display a poorer ability to deliver O2 to the exercising tissue compared to men and oxidative demands must be supplemented by a greater fractional O2 extraction. PMID:23994824

Murias, Juan M; Keir, Daniel A; Spencer, Matthew D; Paterson, Donald H

2013-12-01

289

Oil production by entrained pyrolysis of biomass and processing of oil and char  

Energy Technology Data Exchange (ETDEWEB)

Entrained pyrolysis of lignocellulosic material proceeds from a controlled pyrolysis-initiating temperature to completion of an oxygen free environment at atmospheric pressure and controlled residence time to provide a high yield recovery of pyrolysis oil together with char and non-condensable, combustible gases. The residence time is a function of gas flow rate and the initiating temperature is likewise a function of the gas flow rate, varying therewith. A controlled initiating temperature range of about 400.degree. C. to 550.degree. C. with corresponding gas flow rates to maximize oil yield is disclosed.

Knight, James A. (Atlanta, GA); Gorton, Charles W. (Atlanta, GA)

1990-01-02

290

Waste pyrolysis and generation of storable char  

Energy Technology Data Exchange (ETDEWEB)

Sustainable cities require the generation of energy from waste that cannot be economically reused or recycled. This study focuses on slow pyrolysis that can generate a high yield of char along with liquid and gas products from waste. Char is high in energy content, storable and transportable with low cost so that it can be used as an intermediate medium for high efficiency energy conversion. Pre-processed municipal waste pellets, wood and grass were pyrolysed in a batch type reactor for a final temperature ranging from 350 to 700 deg C, and the char products were characterized. The mass yields of char ranged from 55 to 20% for the tested temperature range, recovering 70-30% of energy and 62-30% of carbon in the raw material. The gross calorific value of char was 30-35 MJ kg{sup -1} on a dry ash free basis. The ash content of raw materials was a key parameter for the quality of char, since its proportion increased by 2-4 times in char depending on the mass yield. A significant amount of volatile metals such as Hg, As and Pb in the waste sample was evaporated at 500 deg C. Therefore, evaporation of volatile metals was another important parameter in determining the pyrolysis temperature and fuel residence time. The char did not show significant morphological change in the tested range of temperatures. It was concluded that slow pyrolysis of waste for char production should be performed below 500 deg C in order to increase the energy yield and also to reduce the evaporation of heavy metals. (Author)

Ryu, Changkook; Sharifi, Vida N.; Swithenbank, Jim [Department of Chemical and Process Engineering, The University of Sheffield, Mappin Street, Sheffield S1 3JD, (United Kingdom)

2006-08-01

291

A comprehensive study of methyl decanoate pyrolysis  

International Nuclear Information System (INIS)

The thermal decomposition of methyl decanoate (MD) was studied in a bench-scale pyrolysis set-up equipped with a dedicated on-line analysis section including a GC GC-FID/(TOF-MS). This analysis section enables quantitative and qualitative on-line analyses of the entire reactor effluent with high level of detail including measurement of formaldehyde and water. The reactor temperature was varied from 873 K to 1123 K at a fixed pressure of 1.7 bar and a fixed residence time of 0.5 s, for both high (10molN2/molMD) and low (0.6molN2/molMD) nitrogen dilution. Thus covering a wide conversion range in both dilution regimes. In these experiments, significant amounts of large linear olefins and unsaturated esters were observed at lower temperatures, the amounts of which decreased at higher temperatures in favor of permanent gasses (CO, CO2, CH4) and light olefins. At the highest temperatures more than 5 wt% of mono-aromatic and poly-aromatic components were observed. The acquired dataset was used to validate 3 recently published microkinetic models which were developed to model oxidation and/or pyrolysis of methyl decanoate. The results showed that these models accurately predict the product distribution, although important discrepancies were observed for some major products such as certain unsaturated esters, CO2 and H2O. Reaction path analyses and CBS-QB3 quantum-chemical calculations are presented and discussed in order to explain the observed differences. -- Highlights: ? New extensive experimental dataset for the pyrolysis of methyl decanoate in a tubular reactor. ? A dedicated separation section including on-line GC GC allows to obtain quantitative data for over 150 components. ? High level ab-initio calculations for important reactions of the methyl decanoate decomposition. ? Identification of missing reactions/reaction families/inaccurate kinetics in the presently available kinetic models.

2012-07-01

292

A fast heating-rate thermogravimetric study of the pyrolysis of scrap tyres  

Energy Technology Data Exchange (ETDEWEB)

Pyrolysis of scrap tyres has been investigated by means of non-isothermal thermogravimetric analysis, at heating rates ranging from 5 to 900{degree}C/min and particle sizes of 1 and 3 mm. The occurrence of primary and secondary pyrolysis stages has been recognized at low heating rates. Based on experimental findings and on the relevant literature on pyrolysis of rubber components, a series-parallel reaction network and a kinetic model are proposed. Accordingly, the first stage of weight loss is related to depolymerization of the rubber components. The residue, upon cyclization and crosslinking, degrades in the secondary stage at larger temperatures. Kinetic parameters of primary and secondary pyrolysis and of the cyclization/crosslinking stages are determined on the basis of experimental results obtained under chemical kinetic controlled pyrolysis conditions. At large heating rates distinction between primary and secondary pyrolysis is no longer observed and a single peak of the pyrolysis rate is observed. This phenomenology can be partly related to decreasing extent of cyclization/crosslinking that take place as the heating rate is raised. Moreover, radial non-uniformities of either temperature, overall volatile pressure or concentration can be established at larger heating rates. These can be further responsible for the modification of the pyrolysis pattern. 10 refs., 3 figs., 2 tabs.

Senneca, O.; Salatino, P.; Chirone, R. [Universita degli Studi di Napoli Federico II, Naples (Italy). Dipt. di Ingegneria Chimica

1999-10-01

293

Pyrolysis of furan in a microreactor  

Science.gov (United States)

A silicon carbide microtubular reactor has been used to measure branching ratios in the thermal decomposition of furan, C4H4O. The pyrolysis experiments are carried out by passing a dilute mixture of furan (approximately 0.01%) entrained in a stream of helium through the heated reactor. The SiC reactor (0.66 mm i.d., 2 mm o.d., 2.5 cm long) operates with continuous flow. Experiments were performed with a reactor inlet pressure of 100-300 Torr and a wall temperature between 1200 and 1600 K; characteristic residence times in the reactor are 60-150 ?s. The unimolecular decomposition pathway of furan is confirmed to be: furan (+ M) ? ?-carbene or ?-carbene. The ?-carbene fragments to CH2=C=O + HC?CH while the ?-carbene isomerizes to CH2=C=CHCHO. The formyl allene can isomerize to CO + CH3C?CH or it can fragment to H + CO + HCCCH2. Tunable synchrotron radiation photoionization mass spectrometry is used to monitor the products and to measure the branching ratio of the two carbenes as well as the ratio of [HCCCH2]/[CH3C?CH]. The results of these pyrolysis experiments demonstrate a preference for 80%-90% of furan decomposition to occur via the ?-carbene. For reactor temperatures of 1200-1400 K, no propargyl radicals are formed. As the temperature rises to 1500-1600 K, at most 10% of the decomposition of CH2=C=CHCHO produces H + CO + HCCCH2 radicals. Thermodynamic conditions in the reactor have been modeled by computational fluid dynamics and the experimental results are compared to the predictions of three furan pyrolysis mechanisms. Uncertainty in the pressure-dependency of the initiation reaction rates is a possible a source of discrepancy between experimental results and theoretical predictions.

Urness, Kimberly N.; Guan, Qi; Golan, Amir; Daily, John W.; Nimlos, Mark R.; Stanton, John F.; Ahmed, Musahid; Ellison, G. Barney

2013-09-01

294

Pyrolysis Modelling in a Wood Stove  

Directory of Open Access Journals (Sweden)

Full Text Available A simple empirical model for predicting the pyrolysis rate of fuel packed bed of a woodstove has been presented. The thermolytic behavior of the fuel bed has been approximated by a pseudo-first order reaction. The reaction rate constant has been determined as function of temperature. The effect of orientation of twigs in the fuel bed arrangement and twig diameter on the reaction rate constant has been analyzed. It has been concluded that the effect of twig orientation is insignificant while the peak magnitude of reaction rate constant increased with increasing twig diameter.

RAJESH GUPTA

2010-10-01

295

Gas sensing properties of undoped and antimony doped tin oxide films prepared by spray pyrolysis and electron beam evaporation method  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The thin films of undoped and antimony doped tin oxide films were prepared oil glass substrates by spray pyrolysis and electron beam evaporation techniques. The Substrate temperature was varied between 300 and 370 degrees C in case of spray pyrolysis and 200 degrees C in case of electron beam evaporation. The films were tested as gas sensors in the presence of liquid petroleum gas (LPG) and compressed natural gas (CNG). Undoped and antimony doped tin oxide films prepared by spray pyrolysis we...

2006-01-01

296

Novel technique for coal pyrolysis and hydrogenation product analysis  

Energy Technology Data Exchange (ETDEWEB)

This report covers the second to the last quarter of the last year of the three-year grant period. In the final project year, we are focusing on the pyrolysis and oxidative pyrolysis of benzene and benzene acetylene mixtures (along with the pyrolysis of other C5-C12 compounds) in order to develop the VUV-MS technique for compounds more representative of those in coal pyrolysis applications. In the first quarters of the current project year, we have carried out the pyrolysis of mixtures of these compounds without oxygen in a microflow reactor. The acetylene/benzene mixtures were used to gain a better understanding of the mechanisms of molecular growth in such systems specifically to look at the kinetics of aryl-aryl reactions as opposed to small molecule addition to phenyl radicals. Sarofim and coworkers at MIT have recently demonstrated the importance of these reactions in coal processing environments. In the past, the growth mechanism for the formation of midsized PAH has been postulated to involve primarily successive acetylene additions to phenyl-type radicals, our work confirms this as an important mechanism especially for smaller PAH but also investigates conditions where biaryl formation can play an important role in higher hydrocarbon formation. Two different temperature regimes are considered: below 1000 K, where reactivity is dominated by molecular processes, and above 1000 K, where radical chain mechanisms become the dominant pathway. These experiments were carried out at a large range of total pressures and with different diluents.

Pfefferle, L.D.

1992-01-01

297

Kajian Pembuatan Nanotube Karbon dengan Menggunakan Metode Spray Pyrolysis  

Directory of Open Access Journals (Sweden)

Full Text Available Dalam penelitian ini, nanotube karbon dibuat dengan menggunakan metode spray pyrolysis tanpa menggunakan gas pembawa pada temperatur 850C. Metode ini merupakan metode yang sering digunakan dalam sintesis nanotube karbon karena dapat menghasilkan nanotube karbon dengan kualitas yang baik dengan biaya produksi yang murah. Dalam spray pyrolysis, benzene sebagai sumber karbon terdekomposisi secara termal dengan bantuan ferrocene yang berperan sebagai katalis dalam menghasilkan nanotube karbon. Penelitian dilakukan dengan memvariasikan massa ferrocene dan waktu pemanasan. Dari hasil karakterisasi SEM dan EDX diketahui bahwa perubahan struktur dan diameter nanotube karbon dipengaruhi oleh massa ferrocene yang dilarutkan dalam benzene. Juga diketahui bahwa penambahan waktu pemanasan tidak berpengaruh pada perbaikan struktur nanotube karbon.

Fatimah A Noor

2009-02-01

298

Study of extraction and pyrolysis of Jordan tar sand  

Energy Technology Data Exchange (ETDEWEB)

The extraction and pyrolysis of tar sand from Wadi Isal, Jordan have been investigated. Solvent type, mixing time, temperature, particle size and alkali concentration have been identified as important parameters for bitumen recovery. The results show that hot water extraction is ineffective since a small amount of bitumen has been obtained even at 80degC. Kerosene extraction shows a maximum bitumen recovery of about 43% at 80degC and 180-250 {mu}m particle size. The kinetic parameters of pyrolysis have been determined based on first-order rate expression and their values were in agreement with other published data in the literature. (Author)

Khraisha, Yahya H. [Jordan Univ., Chemical Engineering Dept., Amman (Jordan)

1999-07-01

299

Characterizing the profile of muscle deoxygenation during ramp incremental exercise in young men.  

Science.gov (United States)

This study characterized the profile of near-infrared spectroscopy (NIRS)-derived muscle deoxygenation (?[HHb]) and the tissue oxygenation index (TOI) as a function of absolute (PO(ABS)) and normalized power output (%PO) or oxygen consumption (%VO(2)) during incremental cycling exercise. Eight men (24 5 year) each performed two fatigue-limited ramp incremental cycling tests (20 W min(-1)), during which pulmonary VO(2), ?[HHb] and TOI were measured continuously. Responses from the two tests were averaged and the TOI (%) and normalized ?[HHb] (%?[HHb]) were plotted against %VO(2), %PO and PO(ABS). The overall responses were modelled using a sigmoid regression (y = f ( 0 ) + A/(1 + e(-(-c+dx)))) and piecewise 'double-linear' function of the predominant adjustment of %?[HHb] or TOI observed throughout the middle portion of exercise and the 'plateau' that followed. In ~85% of cases, the corrected Akaike Information Criterion (AIC(C)) was smaller (suggesting one model favoured) for the 'double-linear' compared with the sigmoid regression for both %?[HHb] and TOI. Furthermore, the f ( 0 ) and A estimates from the sigmoid regressions of %?[HHb] yielded unrealistically large projected peak (f ( 0 ) + A) values (%VO(2p) 114.3 17.5; %PO 113.3 9.5; PO(ABS) 113.5 9.8), suggesting that the sigmoid model does not accurately describe the underlying physiological responses in all subjects and thus may not be appropriate for comparative purposes. Alternatively, the present study proposes that the profile of %?[HHb] and TOI during ramp incremental exercise may be more accurately described as consisting of three distinct phases in which there is little adjustment early in the ramp, the predominant increase in %?[HHb] (decrease in TOI) is approximately linear and an approximately linear 'plateau' follows. PMID:22270488

Spencer, Matthew D; Murias, Juan M; Paterson, Donald H

2012-09-01

300

An ill-posed parabolic evolution system for dispersive deoxygenation-reaeration in water  

Science.gov (United States)

We consider an inverse problem that arises in the management of water resources and pertains to the analysis of surface water pollution by organic matter. Most physically relevant models used by engineers derive from various additions and corrections to enhance the earlier deoxygenation-reaeration model proposed by Streeter and Phelps in 1925, the unknowns being the biochemical oxygen demand (BOD) and the dissolved oxygen (DO) concentrations. The one we deal with includes Taylors dispersion to account for the heterogeneity of the contamination in all space directions. The system we obtain is then composed of two reaction-dispersion equations. The particularity is that both Neumann and Dirichlet boundary conditions are available on the DO tracer while the BOD density is free of any conditions. In fact, for real-life concerns, measurements on the DO are easy to obtain and to save. On the contrary, collecting data on the BOD is a sensitive task and turns out to be a lengthy process. The global model pursues the reconstruction of the BOD density, and especially of its flux along the boundary. Not only is this problem plainly worth studying for its own interest but it could also be a mandatory step in other applications such as the identification of the location of pollution sources. The non-standard boundary conditions generate two difficulties in mathematical and computational grounds. They set up a severe coupling between both equations and they are the cause of the ill-posed data reconstruction problem. Existence and stability fail. Identifiability is therefore the only positive result one can search for; it is the central purpose of the paper. Finally, we have performed some computational experiments to assess the capability of the mixed finite element in missing data recovery.

Azaez, M.; Ben Belgacem, F.; Hecht, F.; Le Bot, C.

2014-01-01

 
 
 
 
301

Characterization of the carbon black produced by vacuum pyrolysis of scrap rubber and optimization of the pyrolysis parameters  

Energy Technology Data Exchange (ETDEWEB)

Among the recycling processes which have been considered for discarded tires, the pyrolysis route appears to be very attractive. Pyrolysis of tires transforms the feedstock into noncondensable gases, condensable vapors, and a solid residue mainly consisting of carbon black. If the energy equivalent of carbon black is taken into account, ca 70% of the energy used to manufacture the tire is recovered. The total energy saved by using pyrolysis is therefore ca 170% of the energy which could be obtained by using the tires directly as fuels. The economics of tire pyrolysis depend, among other factors, on the quality and quantity of pyrolytic oil recovered and on the quality of the derived carbon black and its marketability. Experiments were conducted to find the best process conditions for recovering high-quality carbon black, to optimize process conditions for maximum oil yield, and to study the influence of post-thermal treatment on the quality of carbon black samples produced at different decomposition temperatures. Experiments were conducted using a vacuum pyrolysis unit operating at 350-700[degree]C and 0.3-20 kilopascals pressure. Properties of carbon black such as specific surface area, pH, elemental composition, and volatile matter content were determined for the different grades of carbon black produced. The results indicate that these properties are affected by temperature and pressure. Specific surface area attains a maximum at 500[degree]C and decreases with an increase in pressure. Optimum temperature for maximum oil production was ca 420[degree]C. Comparison of spectroscopic and chemical analysis data suggests that during rubber pyrolysis, pyrolytic carbon is probably deposited on the solid residue particles. 62 refs., 22 figs., 33 tabs.

Rastegar, A.

1989-12-01

302

Approximating rapid pyrolysis of coal particles with shrinking core model  

Energy Technology Data Exchange (ETDEWEB)

A mathematical treatment and the results of calculations are presented, showing that at heating rates {gt}10{sup 5} K/s pyrolysis follows a shrinking-core model, being confined to a thin layer within a particle at a temperature different from that of the particle surface, and being controlled entirely by diffusional limitations. 15 refs., 6 figs.

Hajaligol, M.R.; Yi, S.C. (Philip Morris U.S.A., Richmond, VA (USA). Research Center)

1989-01-01

303

Pyrolysis and Oxidation of PAN in Dry Air. Thermoanalytical Methods  

Directory of Open Access Journals (Sweden)

Full Text Available The results of investigations on pyrolysis and oxidation of pure polyacrylonitrile (PAN and its mixture with N,N-dimethylformamide (DMF under non-isothermal conditions at linear change of samples temperature in time are presented. In each case process proceeded in different way. During pyrolysis of pure PAN the material containing mainly the product after PAN cyclization was obtained, while pyrolysis of PAN+DMF mixture gave the product after cyclization and stabilization. Under conditions of measurements, in both temperature ranges, series of gaseous products were formed.For the PAN-DMF system measurements at different samples heating rates were performed. The obtained results were in accordance with the kinetics of heterogeneous processes theory. The process rates in stages increased along with the temperature increase, and TG, DTG and HF function curves were shifted into higher temperature range. This means that the process of pyrolysis and oxidation of PAN in dry air can be carried out in a controlled way.http://dx.doi.org/10.5755/j01.ms.17.1.246

Anna BIEDUNKIEWICZ

2011-03-01

304

ANALYSIS OF VOLATILE PRODUCTS FROM THE SLOW PYROLYSIS OF COAL  

Science.gov (United States)

The report gives results of a study of the evolution of volatile matter from coals of various rank during fixed-and fluid-bed pyrolysis. The pyrolyses were performed at temperatures ranging from 400 to 1000 C and with heating rates ranging from 1.5 to 6.0 C/s. Effects of equilibr...

305

Petrochemicals from oil shale via one-step pyrolysis  

Energy Technology Data Exchange (ETDEWEB)

The one-step pyrolysis process previously studied by the Bureau of Mines in the fifties for conversion of oil shale into petrochemicals has been systematically evaluated. Anvil Point III oil shale was used for the evaluation which included an economic evaluation of the one-step process. Yields of pyrolysis products produced by the process were investigated as functions of temperature (700 to 1100/sup 0/C), residence time (0.2 to 1.5 sec) and carrier gas (N/sub 2/ or CO/sub 2/). Short residence times of pyrolysis of finely ground shale produced low molecular weight aromatics and aliphatics, and economic evaluation suggested that the process is attractively profitable. (BLM)

Mester, Z.C.; Shih, C.C.J.; Dolbear, G.; Sack, S.

1982-01-01

306

A General Mathematical Model of Solid Fuels Pyrolysis  

Energy Technology Data Exchange (ETDEWEB)

The aim of this work is to present and discuss a detailed kinetic model able to describe the devolatilization process of solid fuels, under pyrolysis conditions. The major reason of this interest in a better understanding of pyrolysis and combustion of coal, biomass and solid fuels lies in the increasing concern of the environmental impact of large-scale combustion processes. The common chemical and structural aspects of the different fuels are singled out and used as the starting point to define this mathematical model. The formation of light gases and liquid tars is the first step in the pyrolysis process. A particular attention is also devoted to the generality and flexibility of numerical and mathematical methods. Several comparisons with experimental data are analysed and the molecular weight distributions of the tar from different coals evolved at different temperatures are also discussed.

Migliavacca, G.; Parodi, E. [Stazione Sperimentale per i Combustibili, San Donato Milanese MI (Italy); Bonfanti, L. [ENEL Produzione Ricerca, Pisa (Italy); Faravelli, T.; Pierucci, S.; Ranzi, E. [Department of Chemical Engineering, Politecnico di Milano, Milano (Italy)

2004-07-01

307

Specialists' workshop on fast pyrolysis of biomass  

Energy Technology Data Exchange (ETDEWEB)

This workshop brought together most of those who are currently working in or have published significant findings in the area of fast pyrolysis of biomass or biomass-derived materials, with the goal of attaining a better understanding of the dominant mechanisms which produce olefins, oxygenated liquids, char, and tars. In addition, background papers were given in hydrocarbon pyrolysis, slow pyrolysis of biomass, and techniques for powdered-feedstock preparation in order that the other papers did not need to introduce in depth these concepts in their presentations for continuity. In general, the authors were requested to present summaries of experimental data with as much interpretation of that data as possible with regard to mechanisms and process variables such as heat flux, temperatures, partial pressure, feedstock, particle size, heating rates, residence time, etc. Separate abstracts have been prepared of each presentation for inclusion in the Energy Data Base. (DMC)

1980-01-01

308

Use of an Apple IIe microcomputer for pyrolysis data acquisition  

Energy Technology Data Exchange (ETDEWEB)

An Apple IIe microcomputer is being used to collect data and to control a pyrolysis system. Pyrolysis data for bitumen and kerogen are widely used to estimate source rock maturity. For a detailed analysis of kinetic parameters, however, data must be obtained more precisely than for routine pyrolysis. The authors discuss the program which controls the temperature ramp of the furnace that heats the sample, and collects data from a thermocouple in the furnace and from the flame ionization detector measuring evolved hydrocarbons. These data are stored on disk for later use by programs that display the results of the experiment or calculate kinetic parameters. The program is written in Applesoft BASIC with subroutines in Apple assembler for speed and efficiency.

1988-02-01

309

Chemistry of hydrogen gas preparation by pyrolysis for the measurement of isotope ratios in hydrocarbons  

International Nuclear Information System (INIS)

The conventional oxidation/reduction preparation method for the determination of hydrogen isotope ratios in hydrocarbons suffers from being very time-consuming. A fast method in which the organic hydrogen is directly converted to hydrogen gas is highly desirable. This report discusses the chemistry involved in adapting high-temperature pyrolysis reactions for the direct conversion of organic hydrogen to hydrogen gas for isotope analysis. The report shows that high-temperature pyrolysis can be adapted to hydrogen isotope determinations provided that the organic matter contains only carbon and hydrogen atoms and that the pyrolysis technique is highly standardized

1986-01-01

310

Bio-Fuel Production Assisted with High Temperature Steam Electrolysis  

Energy Technology Data Exchange (ETDEWEB)

Two hybrid energy processes that enable production of synthetic liquid fuels that are compatible with the existing conventional liquid transportation fuels infrastructure are presented. Using biomass as a renewable carbon source, and supplemental hydrogen from high-temperature steam electrolysis (HTSE), these two hybrid energy processes have the potential to provide a significant alternative petroleum source that could reduce dependence on imported oil. The first process discusses a hydropyrolysis unit with hydrogen addition from HTSE. Non-food biomass is pyrolyzed and converted to pyrolysis oil. The pyrolysis oil is upgraded with hydrogen addition from HTSE. This addition of hydrogen deoxygenates the pyrolysis oil and increases the pH to a tolerable level for transportation. The final product is synthetic crude that could then be transported to a refinery and input into the already used transportation fuel infrastructure. The second process discusses a process named Bio-Syntrolysis. The Bio-Syntrolysis process combines hydrogen from HTSE with CO from an oxygen-blown biomass gasifier that yields syngas to be used as a feedstock for synthesis of liquid synthetic crude. Conversion of syngas to liquid synthetic crude, using a biomass-based carbon source, expands the application of renewable energy beyond the grid to include transportation fuels. It can also contribute to grid stability associated with non-dispatchable power generation. The use of supplemental hydrogen from HTSE enables greater than 90% utilization of the biomass carbon content which is about 2.5 times higher than carbon utilization associated with traditional cellulosic ethanol production. If the electrical power source needed for HTSE is based on nuclear or renewable energy, the process is carbon neutral. INL has demonstrated improved biomass processing prior to gasification. Recyclable biomass in the form of crop residue or energy crops would serve as the feedstock for this process. A process model of syngas production using high temperature electrolysis and biomass gasification is presented. Process heat from the biomass gasifier is used to heat steam for the hydrogen production via the high temperature steam electrolysis process. Oxygen produced form the electrolysis process is used to control the oxidation rate in the oxygen-blown biomass gasifier.

Grant Hawkes; James O' Brien; Michael McKellar

2012-06-01

311

Kinetics of coal pyrolysis and devolatilization  

Energy Technology Data Exchange (ETDEWEB)

Research continued on coal pyrolysis and devolatilization. The effects of reaction process on the transient temperature history of a particle have been examined. The reaction process is found to significantly reduce the temperature gradient across a burning particle relative to a nonreactive particle. The pyrolysis process, on the other hand, does not severely affect the temperature history of a heating particle for the kinetic parameters employed. Devolatilization experiments have been performed on various size cuts on an HVA Bituminous coal in entrained flow and heated grid reactors. Weight loss measurements were made in the entrained flow reactor (EFR) and tar yields and molecular weight distributions were measured for the heated grid reactor (HGR) experiments. The results imply the initial phase of the devolatilization of the HVA Bituminous coal is heat transfer controlled because the rate of tar information and evolution is heat transfer controlled. The invariance in EFR ultimate weight loss and low pressure tar yields and characteristics with change in particle size can be explained by morphological considerations of the parent coal particles. The non-symmetric, irregular shapes of the coal particles result in an intraparticle mass distribution much nearer an interphase surface area than that of an equivalent sphere or cube. 5 refs., 37 figs., 9 tabs.

Seery, D.J.; Freihaut, J.D.; Proscia, W.M.

1991-01-01

312

Vacuum Pyrolysis and Related ISRU Techniques  

Science.gov (United States)

A number of ISRU-related techniques have been developed at NASA Goddard Space Flight Center. The focus of the team has been on development of the vacuum pyrolysis technique for the production of oxygen from the lunar regolith. However, a number of related techniques have also been developed, including solar concentration, solar heating of regolith, resistive heating of regolith, sintering, regolith boiling, process modeling, parts manufacturing, and instrumentation development. An initial prototype system was developed to vaporize regolith simulants using a approx. l square meter Fresnel lens. This system was successfully used to vaporize quantities of approx. lg, and both mass spectroscopy of the gasses produced and Scanning Electron Microscopy (SEM) of the slag were done to show that oxygen was produced. Subsequent tests have demonstrated the use of a larger system With a 3.8m diameter reflective mirror to vaporize the regolith. These results and modeling of the vacuum pyrolysis reaction have indicated that the vaporization of the oxides in the regolith will occur at lower temperature for stronger vacuums. The chemical modeling was validated by testing of a resistive heating system that vaporized quantities of approx. 10g of MLS-1A. This system was also used to demonstrate the sintering of regolith simulants at reduced temperatures in high vacuum. This reduction in the required temperature prompted the development of a small-scale resistive heating system for application as a scientific instrument as well as a proof-of principle experiment for oxygen production.

Cardiff, Eric H.; Pomeroy, Brian R.; Banks, Ian S.; Benz, Alexis

2007-01-01

313

STEPWISE ISOTHERMAL FAST PYROLYSIS (SIFP. PART II. SIFP OF PEANUT SHELLS - ANTIFUNGAL PROPERTIES OF PHENOLIC FRACTIONS  

Directory of Open Access Journals (Sweden)

Full Text Available Pyrolysis of peanut shells was carried out using stepwise isothermal fast pyrolysis (SIFP. SIFP consists of successive isothermal fast pyrolysis reactions, where solid products obtained in the previous isothermal fast pyrolysis become the substrate of the subsequent reaction at a higher temperature. This article reports results obtained from SIFP of peanut shells between 200 and 300C using 100C intervals under vacuum (0.2 mm. The maximum yield of liquid products was obtained at 300C, giving around 30% of bio-oil, which contained mainly phenols and furan derivatives. On the other hand, since previous papers have reported fungicidal activity of phenols derivatives from lingo-cellulosic biomass pyrolysis, we carried out antifungal activity tests of bio oil obtained from peanut shells SIFT at 300 C. Results seem promising, at least on Sclerotium rolfsii.

Jorge Daniel Prez

2011-11-01

314

Pyrolysis of Softwood Carbohydrates in a Fluidized Bed Reactor  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In the present work pyrolysis of pure pine wood and softwood carbohydrates, namely cellulose and galactoglucomannan (the major hemicellulose in coniferous wood), was conducted in a batch mode operated fluidized bed reactor. Temperature ramping (5°C/min) was applied to the heating until a reactor temperature of 460 °C was reached. Thereafter the temperature was kept until the release of non-condensable gases stopped. The different raw materials gave significantly different bio-...

Atte Aho; Narendra Kumar; Kari Eränen; Bjarne Holmbom; Mikko Hupa; Tapio Salmi; Dmitry Yu. Murzin

2008-01-01

315

Pyrolysis of Softwood Carbohydrates in a Fluidized Bed Reactor  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In the present work pyrolysis of pure pine wood and softwood carbohydrates, namely cellulose and galactoglucomannan (the major hemicellulose in coniferous wood), was conducted in a batch mode operated fluidized bed reactor. Temperature ramping (5 C/min) was applied to the heating until a reactor temperature of 460 C was reached. Thereafter the temperature was kept until the release of non-condensable gases stopped. The different raw materials gave significantly different bio-oils. Levoglu...

Aho, Atte; Kumar, Narendra; Era?nen, Kari; Holmbom, Bjarne; Hupa, Mikko; Salmi, Tapio; Murzin, Dmitry Yu

2008-01-01

316

Development of advanced technologies for biomass pyrolysis  

Science.gov (United States)

The utilization of biomass resources as a renewable energy resource is of great importance in responding to concerns over the protection of the environment and the security of energy supply. This PhD research focuses on the investigation of the conversion of negative value biomass residues into value-added fuels through flash pyrolysis. Pyrolysis Process Study. A pilot plant bubbling fluidized bed pyrolyzer has been set up and extensively used to thermally crack various low or negative value agricultural, food and biofuel processing residues to investigate the yields and quality of the liquid [bio-oil] and solid (bio-char] products. Another novel aspect of this study is the establishment of an energy balance from which the thermal self-sustainability of the pyrolysis process can be assessed. Residues such as grape skins and mixture of grape skins and seeds, dried distiller's grains from bio-ethanol plants, sugarcane field residues (internal bagasse, external and whole plant) have been tested. The pyrolysis of each residue has been carried out at temperatures ranging from 300 to 600C and at different vapor residence times, to determine its pyrolysis behavior including yields and the overall energy balance. The thermal sustainability of the pyrolysis process has been estimated by considering the energy contribution of the product gases and liquid bio-oll in relation to the pyrolysis heat requirements. The optimum pyrolysis conditions have been identified in terms of maximizing the liquid blo-oil yield, energy density and content of the product blo-oil, after ensuring a self-sustainable process by utilizing the product gases and part of char or bio-oil as heat sources. Adownflow pyrolyzer has also been set up. Preliminary tests have been conducted using much shorter residence times. Bio-oil Recovery. Bio-oil recovery from the pyrolysis unit includes condensation followed by demisting. A blo-oil cyclonic condensing system is designed A nearly tangential entry forces the entering vapors and gases to spin, providing good heat transfer and driving the condensed droplets to the wall through cyclonic action. This condenser design has been successfully demonstrated for the application on the pilot fluidized bed pyrolysis unit. After condensation, a stable aerosol is also typically formed which is difficult to be efficiently captured with conventional technologies. A pilot scale helicoidal rotary demister, a novel technology for removing persistent fine bio-oil droplets from gases using dynamic centrifugal forces, has been developed. The demister uses a helicoidal element, which consists of a metal sheet wound as a spiral, designed to rotate at high speeds within a cyclone body. Larger droplets are separated as they enter the cyclone housing, while the smaller droplets are carried by the gas into the helicoidal path of the rotating element, where they are centrifuged towards the outer collecting walls and, as a result of a specially designed baffle, may flow counter-currently to the gas and are drained out from the bottom of the rotating element. The mist-free gas leaves through a channel located at the center of the spiral. This unique demister design has demonstrated a high separation efficiency when tested offline with artificial submicron mist and tested online for demisting bio-oil aerosol on the pyrolysis unit. Bio-oil Upgrading: Very often, phase separation of bio-oil occurs naturally upon condensation of the bio-oil vapors, typically through the use of cyclonic condensers. The bio-oil is separated into an organic phase and an aqueous phase. Research has been conducted on the possibility to enhance the fuel properties and energy performance of the organic phase by reducing its water content, enhancing its heating value and improving its stability. Through the use of drying agents, a remarkable reduction of water content and an increase of heating value can be achieved. Moreover, the volumetric energy density can be greatly enhanced. Besides, the energy yield of the process has also been investigated. (Abstract shortened by

Xu, Ran

317

Molecular characterization of vitrinite maturation as revealed by flash pyrolysis methods  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Curie-point pyrolysis - gas chromatography analyses were performed on four vitrinite concentrates of maturity levels from 0.96 %Rmax to 1.93 %Rmax. Analyses were carried out on "thermal extracts" obtained at a Curie-temperature of 358 C and on pyrolysates obtained at a Curie-temperature of 770 C. The relative concentrations of alkylphenols and alkylnaphthalenes decrease with increasing maturity. Alkylbenzenes are prominent pyrolysis products throughout the maturity interval invest...

1994-01-01

318

Co-pyrolysis of coal with organic solids  

Energy Technology Data Exchange (ETDEWEB)

The co-pyrolysis of high volatile A bituminous coal with solid organic materials (proteins, cellulose, polyisoprene, polystyrene, polyethylene-glycolterephtalate-PEGT) at a high temperature conditions was investigated. Aim of the work was to evaluate, firstly, the changes of the texture and of the porous system of solid phase after high temperature treatment in presence of different types of macromolecular solids, secondly, properties and composition of the tar and gas. Considered organic solids are important waste components. During their co-pyrolysis the high volatile bituminous coal acts as a hydrogen donor in the temperature rank 220-480{degrees}C. In the rank 500- 1000{degrees}C the solid phase is formed. The co-pyrolysis was carried out at heating rate 3 K/min. It was found that an amount of organic solid (5-10%) affects important changes in the optical texture forms of solid phase, in the pore distribution and in the internal surface area. Transport large pores volume decreases in presence of PEGT, polystyrene and cellulose and increases in presence of proteins and polyisoprene. (image analysis measurements show that the tendency of coal to create coarse pores during co-pyrolysis is very strong and increases with increasing amount of organic solid in blend). An addition of considered materials changes the sorption ability (methylene blue test, iodine adsorption test), moreover, the reactivity of the solid phase.

Straka, P.; Buchtele, J. [Inst. of Rock Structure and Mechanics, Prague (Czechoslovakia)

1995-12-01

319

Co-pyrolysis of coal and used tyres  

Energy Technology Data Exchange (ETDEWEB)

Previous works performed in our laboratory, as well on coal pyrolysis as on used tyres pyrolysis, led us to propose their reciprocal upgrading by co-pyrolysis. Different proportions of waste tyre were pyrolysed between 560 and 760 C with coal in a 100 cm{sup 3} static batch reactor in a N{sub 2} atmosphere. The yields and the composition of gases, oils and chars were determined in relation to pyrolysis temperature and tyre content. An increase of temperature favours oil and gas formation. The partial substitution of coal by used tyre has a positive effect on oils production, but at high temperature, part of oils is decomposed into gas and char. The presence of scrap tyres doesn`t extract more oils from coal, but improves the oils quality, increasing the yields in light aromatic compounds (BTX) and the formation of products with high value, like limonene. The mechanical properties of the chars are not appreciably modified by addition of a low percentage of tyre to coal. (orig.)

Laurent, P.; Brackman-Danheux, C.; Fontana, A.; Lecharlier, M. [Universite Libre de Bruxelles (Belgium). Faculte des Sciences Appliquee

1997-12-31

320

Modeling and experimental verification of physical and chemical processes during pyrolysis of a refuse-derived fuel  

Energy Technology Data Exchange (ETDEWEB)

A model for refuse-derived fuel (RDF) conventional pyrolysis in a fixed-bed reactor is presented. The model investigates the influence of the heat- and mass-transfer processes on the pyrolysis product yields. Solid degradation reactions have been modeled by assuming that the interactions between the main RDF components during pyrolysis are negligible and that the RDF pyrolysis behavior may be considered as the sum of the separate behaviors of primary reacting species. The model accounts for conductive and convective heat transfer within the solid matrix and secondary tar-cracking reactions, as well as for variability in physical properties and in the void fraction of the pyrolyzing material. Quite good agreement was found between model results and experimental data obtained for conventional pyrolysis of a RDF in a laboratory-scale fixed-bed reactor. The model is able to predict the temperature transients, the rate of gas generation, and the product final yields during conventional pyrolysis of RDF.

Cozzani, V.; Tognotti, L. [Univ. degli Studi di Pisa (Italy); Nicolella, C.; Rovatti, M. [Univ. degli Studi di Genova (Italy). Ist. di Scienze e Tecnologie dell`Ingegneria Chimica

1996-01-01

 
 
 
 
321

Fast pyrolysis of lignin, macroalgae and sewage sludge  

Energy Technology Data Exchange (ETDEWEB)

Non-conventional biomass feedstock may also be applicable for fast pyrolysis processes. Among the forms of non-conventional biomasses, macroalgae, lignin (industrial residue) and sewage sludge may be attractive materials due to their low price, non-competitiveness with food crops and the possible utilization of solid wastes. Besides, a fast pyrolysis process can be used as a process to densify the biomass and produce bioslurry, a mixture of bio-oil and pyrolytic char. The bioslurry is found to be a possible feedstock for pressurized gasification plants. Thus, the aims of this project are to investigate fast pyrolysis properties of lignin, sewage sludge and macroalgae on a lab scale PCR and characterize their bio-oil properties. Bioslurry properties with respect to use as a feedstock for pressurized gasification is also investigated. Lignin and sewage sludge PCR pyrolysis provided bio-oil yields of 47 and 54 wt% daf, and oil energy recovery of 45 and 50 %, respectively. While the macroalgae PCR pyrolysis showed promising results with an organic oil yield of 65 wt% daf and an oil energy recovery of 76 %. The HHV of the lignin, sewage sludge and macroalgae oils were 29.7, 25.7 and 25.5 MJ/kg db respectively, and that are higher than that of typical bioiv oil from conventional biomasses (23-24 MJ/kg db). Almost all metals feedstock contents were contained in the chars at temperatures of 550 - 575 deg. C for lignin, sewage sludge and macroalgae PCR pyrolysis. Due to high feedstock nitrogen and sulfur contents, also a high level of nitrogen and sulfur of macroalgae and sewage sludge oils were observed compared to conventional bio-oil and this may limit their further industrial applications. The lignin char had a high proportion of small size particles, a HHV of 21 MJ/kg db and were almost free of chloride and sulfur, thus it is considered as a promising fuel for gasification or combustion; whereas macroalgae and sewage sludge chars containing high amounts of macronutrients as N, P, K, S, Mg and Ca and this could make the chars most valuable as raw materials for fertilizer production. The sewage sludge waste bulk volume (the char compared to the sludge) was reduced with 52 % by pyrolysis at 575 deg. C. It is seen that the fast pyrolysis process provides a promising method to reduce cost for landfilling and produce a bio-oil that can be used as a fuel. The pyrolysis temperature has a considerable effect on the product distributions of the lignin and sewage sludge PCR pyrolysis, as well as their bio-oil properties with respect to molecular mass distribution, identified GC-MS component compositions, water-insoluble fraction, viscosity, and HHV. A maximum of organic oil yields of lignin and sewage sludge PCR pyrolysis were obtained at optimal temperatures of 550 - 575 deg. C. In this work, the behaviors of slurry samples of wood, char and grinded char with respect to phase transitions, rheological properties, elemental composition, and energy density were investigated. Also pumping properties were investigated at temperatures of 25, 40 and 60 deg. C and the solids loading of 0 - 20 wt%. The bioslurries obtained a volume energy density of 21-23 GJ/m{sup 3} and an energy densification factor of 4.5 - 5 (when compared to beech wood). Their apparent viscosities were significantly influenced by the solid loading levels (0 - 20 wt %) and temperatures (25 - 60 deg. C). The slurry samples with 10 wt% char (having d80 of 276 {mu}m) and 20 wt% grinded char (having d80 of 118 {mu}m) were successfully pumped into a pressurized chamber (0 - 6 bar). (LN)

Trinh, N.T.

2013-04-15

322

Energy recovery from pyrolysis and gasification of mangrove  

International Nuclear Information System (INIS)

Highlights: ? The increase in reactor temperature increased the hydrogen yield and energy yield. ? The increase in reactor temperature increased the peak value of syngas flow rate. ? Cumulative yield of energy was calculated based on the time dependent results. ? Higher reactor temperatures shortened the time duration for 99% release of syngas. ? Gasification yielded more hydrogen and energy than that obtained from pyrolysis. -- Abstract: Mangrove is a biomass material that grows in wetland sea waters and is often used to produce charcoal due to its unique characteristics of long and sustained burning and negligible residue. High temperature pyrolysis has been conducted for mangrove biomass in a laboratory scale semi-batch reactor. The effect of reactor temperature on syngas yield and syngas characteristics has been investigated. Reactor temperature was varied from 600 to 900 C in 100 C intervals. The increase in reactor temperature resulted in increased syngas yield, hydrogen yield and energy yield. Evolutionary behavior of the syngas characteristics has also been investigated. The increase in reactor temperature increased the peak value of syngas flow rate, hydrogen flow rate and output power. The increase in reactor temperature decreased the time duration of pyrolysis. Cumulative yield of syngas, hydrogen and energy was calculated based on the time dependent relationship. Higher reactor temperatures shortened the time duration required for 99% release of syngas, hydrogen and energy. For example, time duration required for 99% yield of hydrogen was approximately 73 min at 600 C and only about 26 min at 900 C. Required time duration for 99% yield of energy was ?62 min at 600 C and ?15 min at 900 C. The gasification of the same material at 900 C has been carried out to determine the role of gasifying agent on the fate of material and resulting syngas properties. The results showed gasification yielded more syngas, hydrogen and energy than that obtained from pyrolysis.

2012-03-01

323

Nanocrystalline Chalcopyrite Materials (CuInS2 and CuInSe2) via Low-Temperature Pyrolysis of Molecular Single-Source Precursors  

Science.gov (United States)

Nanometer sized particles of the chalcopyrite compounds CuInS2 and CuInSe2 were synthesized by thermal decomposition of molecular single-source precursors (PPh3)2CuIn(SEt)4 and (PPh3)2CuIn(SePh)4, respectively, in the non-coordinating solvent dioctyl phthalate at temperatures between 200 and 300 C. The nanoparticles range in size from 3 - 30 nm and are aggregated to form roughly spherical clusters of about 500 nm in diameter. X-ray diffraction of the nanoparticle powders shows greatly broadened lines indicative of very small particle sizes, which is confirmed by TEM. Peaks present in the XRD can be indexed to reference patterns for the respective chalcopyrite compounds. Optical spectroscopy and elemental analysis by energy dispersive spectroscopy support the identification of the nanoparticles as chalcopyrites.

Castro, Stephanie L.; Bailey, Sheila G.; Raffaelle, Ryne P.; Banger, Kulbinder K.; Hepp, Aloysius F.

2003-01-01

324

Nanocrystalline CuInS2 And CuInSe2 via Low-Temperature Pyrolysis Of Single-Source Molecular Precursors  

Science.gov (United States)

Single-source precursors are molecules which contain all the necessary elements for synthesis of a desired material. Thermal decomposition of the precursor results in the formation of the material with the correct stoichiometry, as a nanocrystalline powder or a thin film. Nanocrystalline materials hold potential as components of next-generation Photovoltaic (PV) devices. Presented here are the syntheses of CuInS2 and CuInSe2 nanocrystals from the precursors (PPh3)2CuIn(SEt)4 and (PPh3)2CuIn(SePh)4, respectively. The size of the nanocrystals varies with the reaction temperature; a minimum of 200 C is required for the formation of the smallest CuInS2 crystals (approximately 1.6 nm diameter); at 300 C, crystals are approximately 7 nm.

Castro, Stephanie L.; Bailey, Sheila G.; Raffaelle, Ryne P.; Banger, Kulbinder K.; Hepp, Aloysius F.

2002-01-01

325

Flash pyrolysis fuel oil: bio-pok  

Energy Technology Data Exchange (ETDEWEB)

Samples of flash pyrolysis liquid produced by Union Fenosa, Spain from pine and straw and samples produced by Ensyn of Canada from mixed hardwoods were combusted with simple pressure atomization equipment commonly used with light fuel oils in intermediate size (0.1-1 MW) boilers. With a number of modifications to the combustion system, carbon monoxide (CO) and nitrous oxide (NO{sub x}) could be reduced to acceptable levels: CO < 30 ppm and NO{sub x} < 140 ppm. Particulate emissions which were initially very high (Bacharach 4-5) were reduced (Bach. 2-3) by system improvements but are still higher than from light fuel oil (Bach. <1). The modifications to the combustion system were: refractory section between burner and boiler, acid resistant progressive cavity pump, higher liquid preheat temperature and higher pressure than for light fuel oils. The main problems with pyrolysis liquids concerns their instability or reactivity. At temperatures above 100 deg C they begin to coke, their viscosity increases during storage and oxygen from air causes skin formation. This requires that special handling procedures are developed for fuel storage, delivery and combustion systems. (orig.)

Gust, S. [Neste Oy, Porvoo (Finland)

1997-12-01

326

Pyrolysis oil from carbonaceous solid wastes in Malaysia  

International Nuclear Information System (INIS)

The agro-industrial sector of Malaysia produces a huge amount of oil palm and paddy rice. These generate a significant amount of renewable biomass solid wastes in the forms of oil palm shell and rice husk. Apart from this a huge quantity of scrap tyre is generated from the country's faster increasing usage of transportation vehicles like motorcycle, car, bus and lorries. These wastes are producing pollution and disposal problems affecting the environment. Besides energy is not recovered efficiently from these waste resources. From the elemental composition and thermogravimetric analysis (TGA) studies of the wastes, it appeared that the wastes could be used for pyrolysis liquid oil production. Pyrolysis at present is deemed to be a potential method for the conversion of carbonaceous solid wastes into upgraded liquid products which can either be tried for liquid fuel or value-added chemical. A fluidized bed bench scale fast pyrolysis system was employed for this thermochemical conversion process of solid wastes. Silica sand was used as fluidized bed material and nitrogen gas as the fluidising medium. The products obtained were liquid oil, solid char and gas. The liquid oil and solid char were collected separately while the gas was flared. The maximum liquid product yield was found to vary with feedstock material fluidized bed temperature. The maximum liquid product yield was found to be 58, 53 and 40 wt. % of biomass fed at fluidized bed temperature at 500, 525 and 4500C respectively for oil palm shell, scrap tyre and rice husk. The solid char yield was 25, 36 and 53 wt. % of biomass fed at the condition of maximum liquid product yield for oil palm shell, scrap tyre and rice husk respectively. The oil products were subjected to FTIR, GC and GC/MS analysis for their group composition and detailed chemical compositions. The pyrolysis oil from scrap tyre was found to contain highest percentage of pure hydrocarbons (25 wt. % of total feed) with esters and oxygenated hydrocarbons containing silicone. The phenols were found to be maximum in case of oil palm shell pyrolysis oil (35 wt. % of total feed) with organic acids, alcohol, ketones and hydrocarbons. The pyrolysis oil from rice husk contained a maximum. percentage of ketones (28 wt. % of total feed) with acids, aldehydes, alcohol, phenols and hydrocarbons. Thus, the compounds were found to be prospectful for fuel and chemicals. The physical properties of the pyrolysis oils were presented and compared with typical wood pyrolysis oil. (Author)

1999-06-08

327

Bio-oil from flash pyrolysis of agricultural residues  

Energy Technology Data Exchange (ETDEWEB)

This thesis describes the production of bio-oils from flash pyrolysis of agricultural residues, using a pyrolysis centrifugal reactor (PCR). It has been the objective of the present work to investigate the influence of changed operation conditions on the yield of bio-oil, char and gas; as well as to investigate the composition and storage properties of some of the produced bio-oils. Mainly the influence of feedstock type (wheat straw, rice husk and pine wood), feedstock water content and reactor temperature on the yield of char, bio-oil and gas were investigated. The storage stability of bio-oils with respect to changes in viscosity, water content and pH were investigated for straw and pine wood oil at different temperature and residence times. Temperature plays a major role in the pyrolysis process and it determines to a high degree the fate of the final product yields and also product composition. Higher temperature favors the formation of pyrolysis gas while lower temperatures increase the yield of char. Liquid oil, however increases with temperature up to certain point and thereafter it decreases at still higher temperature due to secondary cracking of the primary products. The presence of moisture in the feed stock may also influences the pyrolysis process. The influence of reaction temperature and the moisture content on the flash pyrolysis product yield has been reported in Paper I (Chapter 2). It was observed that the presence of moisture in the wheat straw with different moisture levels of 1.5 wt. %, 6.2 wt. % and 15.0 wt. % have shown no significant effect on the pyrolysis product distribution. The fraction of bio-oil, char and gases produced from pyrolysis of straw were in the range of 40-60 wt. %, 18-50 wt. % and 5-22 wt. %, respectively, regardless of the straw moisture levels. The optimal reaction temperature for the production of bio-oil was around 525 deg. C to 550 deg. C for all straw moisture contents. It was investigated how differences in biomass composition influence pyrolysis products yields and the composition of char and bio-oils. Details about this investigation are explained in Paper II (Chapter 3). The used pine wood had a low ash content (0.5 wt. %), the wheat straw an intermediate ash level (6.0 wt. %) and the rice husk a high ash level (13.6 wt. %). The highest alkali content, potassium (1.53 wt. %) are present in straw and the lowest potassium content level is observed in pine wood (0.04 wt. %). The feedstocks were pyrolyzed at reactor temperatures ranging from 475 to 575 deg. C. It was observed that the formation of char and gas is affected by the biomass alkali content. Increasing biomass alkali content caused an increased feedstock conversion at low temperature, a lower maximum liquid organic yield temperature and a lower maximum liquid organics yield. In addition, the chemical compositions of the bio-oils and the chars of the investigated feedstocks were also analyzed. The utilization of the pyrolysis oil in static combustion equipments such as boilers and turbine have shown that the suitability of the pyrolysis oil to substitute fossil fuel. However, several limitations still arise due to the instability of the pyrolysis oil that may cause problems with transport and storage. Pyrolysis oil contains more than hundred of chemical compounds and has a wide range of volatility (different boiling points). The stability and aging of bio-oils generated by bench scale pyrolysis of wheat straw and pine wood are discussed in Paper III (Chapter 4). It was found that the bio-oil from wheat straw shows better stability compared to the bio-oil from pine wood. In addition, both bio-oils are fairly stable stored in a closed container at room temperature for up to 130 days, with no phase separation and only small changes in physical properties were observed. The combustion behavior of pyrolysis oils derived from wheat straw and pine wood are investigated and discussed in Paper IV (Chapter 5). The investigation is done in two parts. In the first part, the technique of thermogravimetric analysis (TGA) was

Ibrahim, N.B.

2012-08-15

328

Development of a high-performance coal-fired power generating system with pyrolysis gas and char-fired high temperature furnace (HITAF)  

Energy Technology Data Exchange (ETDEWEB)

A concept for an advanced coal-fired combined-cycle power generating system is currently being developed. The first phase of this three-phase program consists of conducting the necessary research and development to define the system, evaluating the economic and technical feasibility of the concept, and preparing an R D plan to develop the concept further. The power generating system being developed in this project will be an improvement over current coal-fired systems. Goals have been specified that relate to the efficiency, emissions, costs, and general operation of the system. The system proposed to meet these goals is a combined-cycle system where air for a gas turbine is indirectly heated to approximately 1800[degrees]F in furnaces fired with coal-derived fuels and then directly heated in a natural-gas-fired combustor to about 2400[degrees]F. The system is based on a pyrolyzing process that converts the coal into a low-Btu fuel gas and char. The fuel gas is relatively clean, and it is fired to heat tube surfaces that are susceptible to corrosion and problems from ash deposition. In particular, the high-temperature air heater tubes, which will need to be a ceramic material, will be located in a separate furnace or region of a furnace that is exposed to combustion products from the low-Btu fuel gas only.

1993-02-01

329

Development of a high-performance, coal-fired power generating system with a pyrolysis gas and char-fired high-temperature furnace  

Energy Technology Data Exchange (ETDEWEB)

A high-performance power system (HIPPS) is being developed. This system is a coal-fired, combined-cycle plant that will have an efficiency of at least 47 percent, based on the higher heating value of the fuel. The original emissions goal of the project was for NOx and SOx to each be below 0.15 lb/MMBtu. In the Phase 2 RFP this emissions goal was reduced to 0.06 lb/MMBtu. The ultimate goal of HIPPS is to have an all-coal-fueled system, but initial versions of the system are allowed up to 35 percent heat input from natural gas. Foster Wheeler Development Corporation is currently leading a team effort with AlliedSignal, Bechtel, Foster Wheeler Energy Corporation, Research-Cottrell, TRW and Westinghouse. Previous work on the project was also done by General Electric. The HIPPS plant will use a high-Temperature Advanced Furnace (HITAF) to achieve combined-cycle operation with coal as the primary fuel. The HITAF is an atmospheric-pressure, pulverized-fuel-fired boiler/air heater. The HITAF is used to heat air for the gas turbine and also to transfer heat to the steam cycle. its design and functions are very similar to conventional PC boilers. Some important differences, however, arise from the requirements of the combined cycle operation.

Shenker, J.

1995-11-01

330

Characteristics of SnO2:F Thin Films Deposited by Ultrasonic Spray Pyrolysis: Effect of Water Content in Solution and Substrate Temperature  

Directory of Open Access Journals (Sweden)

Full Text Available Fluorine doped tin oxide, SnO2:F, thin films were deposited by ultrasonic chemical spray starting from tin chloride and hydrofluoric acid. The physical characteristics of the films as a function of both water content in the starting solution and substrate temperature were studied. The film structure was polycrystalline in all cases, showing that the intensity of (200 peak increased with the water content in the starting solution. The electrical resistivity decreased with the water content, reaching a minimum value, in the order of 8 10-4 ?cm, for films deposited at 450? from a starting solution with a water content of 10 ml per 100 ml of solution; further increase in water content increased the corresponding resistivity. Optical transmittances of SnO2:F films were high, in the order of 75%, and the band gap values oscillated around 3.9 eV. SEM analysis showed uniform surface morphologies with different geometries depending on the deposition conditions. Composition analysis showed a stoichiometric compound with a [Sn/O] ratio around 1:2 in all samples. The presence of F into the SnO2 lattice was detected, within 2 at % respect to Sn.

Mario A. Snchez-Garca

2012-10-01

331

Development of a high-performance, coal-fired power generating system with a pyrolysis gas and char-fired high-temperature furnace  

International Nuclear Information System (INIS)

A high-performance power system (HIPPS) is being developed. This system is a coal-fired, combined-cycle plant that will have an efficiency of at least 47 percent, based on the higher heating value of the fuel. The original emissions goal of the project was for NOx and SOx to each be below 0.15 lb/MMBtu. In the Phase 2 RFP this emissions goal was reduced to 0.06 lb/MMBtu. The ultimate goal of HIPPS is to have an all-coal-fueled system, but initial versions of the system are allowed up to 35 percent heat input from natural gas. Foster Wheeler Development Corporation is currently leading a team effort with AlliedSignal, Bechtel, Foster Wheeler Energy Corporation, Research-Cottrell, TRW and Westinghouse. Previous work on the project was also done by General Electric. The HIPPS plant will use a high-Temperature Advanced Furnace (HITAF) to achieve combined-cycle operation with coal as the primary fuel. The HITAF is an atmospheric-pressure, pulverized-fuel-fired boiler/air heater. The HITAF is used to heat air for the gas turbine and also to transfer heat to the steam cycle. its design and functions are very similar to conventional PC boilers. Some important differences, however, arise from the requirements of the combined cycle operation

1995-07-12

332

Influence of Pyrolysis Parameters on the Performance of CMSM  

Directory of Open Access Journals (Sweden)

Full Text Available Carbon hollow fiber membranes have been prepared by pyrolysis of a P84/S-PEEK blend. Proximate analysis of the precursor was performed using thermogravimetry (TGA, and a carbon yield of approximately 40% can be obtained. This study aimed at understanding the influence of pyrolysis parametersend temperature, quenching effect, and soaking timeon the membrane properties. Permeation experiments were performed with N2, He, and CO2. Scanning electron microscopy (SEM has been done for all carbon hollow fibers. The highest permeances were obtained for the membrane submitted to an end temperature of 750C and the highest ideal selectivities for an end temperature of 700C. In both cases, the membranes were quenched to room temperature.

Marta C. Campo

2009-01-01

333

Pyrolysis characteristic of tobacco stem studied by Py-GC/MS, TG-FTIR, and TG-MS  

Directory of Open Access Journals (Sweden)

Full Text Available Pyrolysis characteristics and mechanism of tobacco stem were studied by pyrolysis coupled with gas chromatography/mass spectrometry (Py-GC/MS, thermogravimetric analyzer coupled with Fourier transform infrared spectrometry, and mass spectrometry (TG-FTIR and TG-MS techniques. The composition of evolved volatiles from fast pyrolysis of tobacco stem was determined by Py-GC/MS analysis, and the evolution patterns of the major products were investigated by TG-FTIR and TG-MS. Py-GC/MS data indicated that furfural and phenol were the major products in low temperature pyrolysis, and these were generated from depolymerization of cellulose. Indene and naphthalene were the major products in high temperature pyrolysis. TG-FTIR and TG-MS results showed that CO, CO2, phenols, aldehydes, and ketones were released between 167C and 500C; at temperatures >500C, CO and CO2 were the main gaseous products.

Bei Liu

2013-02-01

334

Co-pyrolysis of low rank coals and biomass: Product distributions  

Energy Technology Data Exchange (ETDEWEB)

Pyrolysis and gasification of combined low rank coal and biomass feeds are the subject of much study in an effort to mitigate the production of green house gases from integrated gasification combined cycle (IGCC) systems. While co-feeding has the potential to reduce the net carbon footprint of commercial gasification operations, the effects of co-feeding on kinetics and product distributions requires study to ensure the success of this strategy. Southern yellow pine was pyrolyzed in a semi-batch type drop tube reactor with either Powder River Basin sub-bituminous coal or Mississippi lignite at several temperatures and feed ratios. Product gas composition of expected primary constituents (CO, CO{sub 2}, CH{sub 4}, H{sub 2}, H{sub 2}O, and C{sub 2}H{sub 4}) was determined by in-situ mass spectrometry while minor gaseous constituents were determined using a GC-MS. Product distributions are fit to linear functions of temperature, and quadratic functions of biomass fraction, for use in computational co-pyrolysis simulations. The results are shown to yield significant nonlinearities, particularly at higher temperatures and for lower ranked coals. The co-pyrolysis product distributions evolve more tar, and less char, CH{sub 4}, and C{sub 2}H{sub 4}, than an additive pyrolysis process would suggest. For lignite co-pyrolysis, CO and H{sub 2} production are also reduced. The data suggests that evolution of hydrogen from rapid pyrolysis of biomass prevents the crosslinking of fragmented aromatic structures during coal pyrolysis to produce tar, rather than secondary char and light gases. Finally, it is shown that, for the two coal types tested, co-pyrolysis synergies are more significant as coal rank decreases, likely because the initial structure in these coals contains larger pores and smaller clusters of aromatic structures which are more readily retained as tar in rapid co-pyrolysis.

Soncini, Ryan M; Means, Nicholas C; Weiland, Nathan T

2013-10-01

335

Catalytic oxidative pyrolysis of spent organic ion exchange resins from nuclear power plants  

International Nuclear Information System (INIS)

The spent IX resins from nuclear power reactors are highly active solid wastes generated during operations of nuclear reactors. Catalytic oxidative pyrolysis of these resins can lead to high volume reduction of these wastes. Low temperature pyrolysis of transition metal ion loaded IX resins in presence of nitrogen was carried out in order to optimize catalyst composition to achieve maximum weight reduction. Thermo gravimetric analysis of the pyrolysis residues was carried out in presence of air in order to compare the oxidative characteristics of transition metal oxide catalysts. Copper along with iron, chromium and nickel present in the spent IX resins gave the most efficient catalyst combination for catalytic and oxidative pyrolysis of the residues. During low temperature catalytic pyrolysis, 137Cesium volatility was estimated to be around 0.01% from cationic resins and around 0.1% from anionic resins. During oxidative pyrolysis at 700 degC, nearly 10 to 40% of 137Cesium was found to be released to off gases depending upon type of resin and catalyst loaded on to it. The oxidation of pyrolytic residues at 700 degC gave weight reduction of 15% for cationic resins and 93% for anionic resins. Catalytic oxidative pyrolysis is attractive for reducing weight and volume of spent cationic resins from PHWRs and VVERs. (author)

2005-01-01

336

Carbon isotope ratio analysis of organic moieties from fossil mummified wood: establishing optimum conditions for off-line pyrolysis extraction using gas chromatography/mass spectrometry  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Mummified fossil wood was studied using off-line pyrolysis-gas chromatography/mass spectrometry to reveal detailed insights into the pyrolysis conditions that are needed to obtain simultaneously sufficient amounts of both cellulose and lignin markers for stable carbon isotope analyses. The off-line pyrolysis was applied at a range of temperatures (200, 250 and 300 C) and times (1 and 2 h) to determine the optimum temperature and time that yielded the highest quantity of true markers for lig...

Poole, I. J.; Bergen, P. F.

2002-01-01

337

Flash pyrolysis and gasification of coal through laser heating  

Energy Technology Data Exchange (ETDEWEB)

Experimental results obtained from the rapid pyrolysis of finely powdered coal are presented. The experiments are designed to provide basic information on gas yield, gas composition, optimum fluxes, and temperature history of coal samples under high intensity laser radiation. The information obtained from these experiments will be used to test concepts for the use of concentrated sunlight to produce fuel gases from coal. Heating the coal at rates of 10/sup 3/ to 10/sup 4/ C/s in an inert atmosphere of argon results in pyrolysis at temperatures between 400 and 800/sup 0/C. The gases evolved are primarily CO, H/sub 2/, and CH/sub 4/ with lesser amounts of CO/sub 2/ and other light hydrocarbons. Mass spectrometry is used to determine the composition of the evolved gases. The optimum flux for laser pyrolysis of coal was found to be 250 W/cm/sup 2/. Results from experiments wherein the char created by pyrolysis is gasified to CO in an atmosphere of CO/sub 2/ are also presented.

Beattie, W.H.; Sullivan, J.A.

1980-01-01

338

Pyrolysis products of uncoated printing and writing paper of MSW  

Energy Technology Data Exchange (ETDEWEB)

Uncoated printing and writing paper, one of the principal waste papers in Taiwan, was pyrolyzed with a thermogravimetric analysis (TGA) reaction system. The pyrolysis experiments were carried out in nitrogen environment at a constant heating rate of 5 K min{sup -1}. The gaseous products and the residues were collected at room temperature (300 K) and analyzed by gas chromatography (GC) and elemental analyzer, respectively. The major gaseous products investigated included non-hydrocarbons (H{sub 2}, CO, CO{sub 2} and H{sub 2}O) and hydrocarbons (C{sub 1-3}, C{sub 4}, C{sub 5}, C{sub 6}, 1-ring, C{sub 10-12}, levoglucosan, C{sub 13=15} and C{sub 16-18}). The cumulated masses and the instantaneous gases were about 10.46 and 0.49% at 623 K, 33.68 and 0.89% at 700 K, 64.52 and 1.05% at 788 K, and 79-10. and 1.63% and 938 K, respectively. The estimation of the mass of tar, yielded at various pyrolysis temperatures was also made. The results of this study might be useful for the design of pyrolysis process as well as for determining the pyrolysis mechanisms of the uncoated printing and writing paper. 23 refs., 1 fig., 6 tabs.

Wu, C.; Chang, C.; Tseng, C. [Da-Yeh University, Chang-Hwa (Taiwan)

2002-04-01

339

Pyrolysis of a waste from the grinding of scrap tyres  

International Nuclear Information System (INIS)

Highlights: ? The pyrolysis of reinforcing fibres obtained from scrap tyres has been studied. ? The results have been compared to scrap tyre granules. ? A higher temperature is needed for the total decomposition of the fibres. ? More compounds with heteroatoms (O, N) were found in the oil from the fibres. ? Chars from the fibres exhibit lower BET surface and mesopore volume. - Abstract: The fibres that are used to reinforce tyres can be recovered as a waste in the process of grinding of scrap tyres. In this paper beneficiation through pyrolysis is studied since the fibres are made up of polymers with a small amount of rubber because the latter is difficult to separate. The experiments were performed at three temperatures (400, 550 and 900 C) in a horizontal oven. The three products gas, oil and char obtained from the pyrolysis were investigated. The composition of the gas was analyzed by means of gas chromatography. The oil was studied by gas chromatography and infrared spectroscopy. The char porous structure was determined by N2 adsorption. In addition, the topography of the chars was studied by means of scanning electron microscopy (SEM). The products resulting from the pyrolysis of the fibres were compared with those obtained from scrap rubber.

2012-02-15

340

The release of nitrogen in coal combustion and pyrolysis  

International Nuclear Information System (INIS)

Environmental aspects of coal utilization are a major concern. Recent advances in the development of low NOx burners and the emerging technologies of fluidized bed combustion have led to the identification of coal char nitrogen as the major contributor to the nitrogen oxides released during combustion. The temperature programmed combustion and pyrolysis of a series of coals covering a wide range of rank have been investigated. In addition, maceral concentrates have been investigated to assess the variation in the combustion behavior and the release of nitrogen in the pyrolysis and combustion of macerals. This investigation has involved the use of thermogravimetric analysis - mass spectrometry (TG-MS) with two sampling options: (1) ?1cm from the sample and (2) at the exit of the TG. The former allows reactive species to be identified in the combustion of the coals. These temperature programmed combustion results have been compared with similar measurements carried out at the exit of the TG where the products are at equilibrium. In addition, pyrolysis studies have been carried out under similar conditions. The results show that reactive intermediate species such as HCN, (CN)2, COS etc. can be detected in the combustion products. The evolution of these species during combustion are compared with the pyrolysis products of the coal. The results are discussed in relation to the structure of the coals and the conversion of volatile species and char nitrogen to nitrogen oxides

1994-08-21

 
 
 
 
341

Methods and apparatuses for preparing upgraded pyrolysis oil  

Energy Technology Data Exchange (ETDEWEB)

Methods and apparatuses for preparing upgraded pyrolysis oil are provided herein. In an embodiment, a method of preparing upgraded pyrolysis oil includes providing a biomass-derived pyrolysis oil stream having an original oxygen content. The biomass-derived pyrolysis oil stream is hydrodeoxygenated under catalysis in the presence of hydrogen to form a hydrodeoxygenated pyrolysis oil stream comprising a cyclic paraffin component. At least a portion of the hydrodeoxygenated pyrolysis oil stream is dehydrogenated under catalysis to form the upgraded pyrolysis oil.

Brandvold, Timothy A; Baird, Lance Awender; Frey, Stanley Joseph

2013-10-01

342

Mechanism of cluster formation during pyrolysis of carborane-4  

International Nuclear Information System (INIS)

The times of cluster formation during pyrolysis of the C2B4H6 carborane within the temperature range of 1150-1950 K and different carborane initial pressure are determined. The mechanism of cluster formation is established. The mathematical model of cluster formation forecasting the effect of temperature and pressure on the clusters dimensions and determining the conditions of their formation is proposed

1998-12-01

343

Thermal stability of thiophene biomarkers as studied by hydrous pyrolysis  

Digital Repository Infrastructure Vision for European Research (DRIVER)

An immature (Ro = 0.25%) sulphur-rich calcareous shale from the Gessoso-solfifera Formation (Messinian) in the Vena del Gesso Basin (northern Italy) was artificially matured by hydrous pyrolysis at constant temperatures ranging from 160 to 330C for 72 h to study the applicability of alkylthiophenes as molecular indicators during progressive diagenesis and early catagenesis. Artificial maturation at temperatures up to 330C generated large amounts of alkylthiophenes from the thermal degrada...

Sinninghe Damste?, J. S.; Koopmans, M. P.; Lewan, M. D.; Leeuw, J. W.

1995-01-01

344

Exploratory studies on fast pyrolysis oil upgrading  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Pyrolysis oil is a dark brown liquid which can be produced in high yield from different kind of biomass sources by means of fast pyrolysis. Pyrolysis oil is considered as a promising second generation energy carrier and may play an important role in the future of "biobased economies". The energy content of pyrolysis oil is approximately half of fossil crude. Just like for crude oil, further reprocessing is necessary to arranged pyrolysis oil as fuel in e.g. combustion engines. This thesis des...

Mahfud, Farchad Husein

2007-01-01

345

Pyrolysis of brown coal mixed with heavy products of coal and petroleum processing  

Energy Technology Data Exchange (ETDEWEB)

Investigates effect of various additives on yield of liquid product from pyrolysis of Kansk-Achinsk (Berezovsk deposit) brown coal mixed with organic additives: waste from caprolactam plant consisting mostly of saturated oxygen containing compounds and mono- and di-carboxylic acid esters, waste from sabatic acid plant consisting predominantly of unsaturated acids, distillation residue of synthetic fatty acids, heavy residue from Arlansk oil refineries containing mainly condensed naphtheno-aromatic systems and heavy tar from rapid pyrolysis of Kansk-Achinsk coal. Finds that joint pyrolysis of brown coal with organic additives increases yield of liquid products and that intensive decomposition begins at lower temperatures. 4 refs.

Vikhorev, A.A.; Syroezhko, A.M.; Proskuryakov, V.A.; Akhmedov, N.A.

1987-03-01

346

Hydrogen atom concentration in the pyrolysis zone of normal C_2-C_6 alkanes  

International Nuclear Information System (INIS)

The authors determined the concentration of hydrogen atoms formed upon the pyrolysis of normal C_2-C_6 alkanes at 700-850 C and 13.3 kPa. these data and previous results were used to characterize the dependence of the hydrogen atom concentration on temperature and pressure. Below 825 C, the hydrogen atom concentration in the pyrolysis zone increases in going from ethane to hexane. Above 825 C, the highest hydrogen atom concentration is obtained in the pyrolysis zone of ethane

1986-01-01

347

Studies on steam pyrolysis of amides as a waste solvent management method  

International Nuclear Information System (INIS)

A laboratory scale pyrolysis reactor set-up was designed and constructed. The steam pyrolysis of dimethyl formamide (DMF) was studied in a tubular flow reactor at atmospheric pressure. The experimental data were obtained at a temperature range of 500-1100 deg C for different flow rates and steam to amide mass ratio. The reaction products were analyzed by gas chromatography and high pressure liquid chromatography. The experimental data was analyzed using a power law model to estimate apparent rate constant and corresponding activation energy. A reaction network model is being developed to include reaction mechanism of steam pyrolysis. (author)

2010-10-01

348

Fuel-N Evolution during the Pyrolysis of Industrial Biomass Wastes with High Nitrogen Content  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In this study, sewage sludge and mycelial waste from antibiotic production were pyrolyzed in a batch scale fixed-bed reactor as examples of two kinds of typical industrial biomass wastes with high nitrogen content. A series of experiments were conducted on the rapid pyrolysis and the slow pyrolysis of these wastes in the temperature range from 500800 C to investigate the Fuel-N transformation behavior among pyrolysis products. The results showed that Fuel-N conversion to Char-N i...

Hongfang Chen; Yin Wang; Guangwen Xu; Kunio Yoshikawa

2012-01-01

349

Production, properties and utilisation of pyrolysis oil  

Energy Technology Data Exchange (ETDEWEB)

In this project VTT Energy co-ordinates the EU JOULE Project `Biofuel oil for power plants and boilers` supporting the development projects of Finnish enterprises, and participates in the Pyrolysis Project of IEA Bioenergy Agreement. Presently two pyrolysis devices with capacities of 150 g/h and 1 kg/h are used for the project. Hot gas filtering tests by using one ceramic candle equipment have been carried out with the 1 kg/h device for pyrolysis oil. The solids and alkali contents of the product oil were reduced clearly. Suitable conditions are being defined for continuous hot gas filtering. A PDU device of 20 kg/h is being commissioned. The main aim of the chemical characterisation of pyrolysis oil was to develop as simple a method as possible for differentiating pyrolysis oils and for finding correlations between the characteristics and behaviour of pyrolysis oils. Pyrolysis oils produced from various raw materials (hardwood, pine, straw) were analysed and compared with each other. VTT Energy participates in the pyrolysis network (EU/PYNE) of EU, the aim of which is to collect and disseminate research results of pyrolysis studies, i.e., through a journal with a wide circulation. VTT also participates in the pyrolysis activity of IEA (PYRA), the other partners being Great Britain, EU, Canada and the United States. I.e., quality criteria and improvement, occupational safety and pyrolysis kinetics are discussed in IEA/PYRA

Sipilae, K.; Oasmaa, A.; Arpiainen, V.; Solantausta, Y.; Leppaemaeki, E.; Kuoppala, E.; Levander, J.; Kleemola, J.; Saarimaeki, P. [VTT Energy, Jyvaeskylae (Finland). Energy Production Technologies

1997-12-01

350

Phosphorus catalysis in the pyrolysis behaviour of biomass  

Energy Technology Data Exchange (ETDEWEB)

Phosphorus is a key plant nutrient and as such, is incorporated into growing biomass in small amounts. This paper examines the influence of phosphorus, present in either acid (H{sub 3}PO{sub 4}) or salt ((NH{sub 4}){sub 3}PO{sub 4}) form, on the pyrolysis behaviour of both Miscanthus x giganteus, and its cell wall components, cellulose, hemicellulose (xylan) and lignin (Organosolv). Pyrolysis-gas chromatography-mass spectrometry (PY-GC-MS) is used to examine the pyrolysis products during thermal degradation, and thermogravimetric analysis (TGA) is used to examine the distribution of char and volatiles. Phosphorus salts are seen to catalyse the pyrolysis and modify the yields of products, resulting in a large increase in char yield for all samples, but particularly for cellulose and Miscanthus. The thermal degradation processes of cellulose, xylan and Miscanthus samples occur in one step and the main pyrolysis step is shifted to lower temperature in the presence of phosphorus. A small impact of phosphorus was observed in the case of lignin char yields and the types of pyrolysis decomposition products produced. Levoglucosan is a major component produced in fast pyrolysis of cellulose. Furfural and levoglucosenone become more dominant products upon P-impregnation pointing to new rearrangement and dehydration routes. The P-catalysed xylan decomposition route leads to a much simpler mixture of products, which are dominated by furfural, 3-methyl-2-cyclopenten-1-one and one other unconfirmed product, possibly 3,4-dihydro-2-methoxy-2H-pyran or 4-hydroxy-5,6-dihydro-(2H)-pyran-2-one. Phosphorus-catalysed lignin decomposition also leads to a modified mixture of tar components and desaspidinol as well as other higher molecular weight component become more dominant relative to the methoxyphenyl phenols, dimethoxy phenols and triethoxy benzene. Comparison of the results for Miscanthus lead to the conclusion that the understanding of the fast pyrolysis of biomass can, for the most part, be gained through the study of the individual cell wall components, provided consideration is given to the presence of catalytic components such as phosphorus. (author)

Nowakowski, Daniel J.; Woodbridge, Charles R.; Jones, Jenny M. [Energy and Resources Research Institute, School of Process, Environmental and Materials Engineering (SPEME), University of Leeds, Leeds, LS2 9JT (United Kingdom)

2008-11-15

351

Fluidized bed selective pyrolysis of coal  

Energy Technology Data Exchange (ETDEWEB)

The present invention discloses a process for the pyrolysis of coal which comprises the effective utilization of two zonal inclined fluidized beds, where said zones can be selectively controlled as to temperature and heating rate. The first zonal inclined fluidized bed serves as a dryer for crushed coal and additionally is controlled to selectively pyrolyze said coal producing substantially carbon dioxide for recycle use. The second zonal inclined fluidized bed further pyrolyzes the coal to gaseous, liquid and char products under controlled temperature and heating rate zones designed to economically integrate the product mix. The gas and liquid products are recovered from the gaseous effluent stream while the char which remains can be further treated or utilized in a subsequent process step.

Shang, Jer Y. (McLean, VA); Cha, Chang Y. (Golden, CO); Merriam, Norman W. (Laramie, WY)

1992-01-01

352

Controlled catalytic and thermal sequential pyrolysis and hydrolysis of mixed polymer waste streams to sequentially recover monomers or other high value products  

Energy Technology Data Exchange (ETDEWEB)

A process of using fast pyrolysis in a carrier gas to convert a plastic waste feedstream having a mixed polymeric composition in a manner such that pyrolysis of a given polymer to its high value monomeric constituent occurs prior to pyrolysis of other plastic components therein comprising: selecting a first temperature program range to cause pyrolysis of said given polymer to its high value monomeric constituent prior to a temperature range that causes pyrolysis of other plastic components; selecting a catalyst and support for treating said feed streams with said catalyst to effect acid or base catalyzed reaction pathways to maximize yield or enhance separation of said high value monomeric constituent in said temperature program range; differentially heating said feed stream at a heat rate within the first temperature program range to provide differential pyrolysis for selective recovery of optimum quantities of the high value monomeric constituent prior to pyrolysis of other plastic components; separating the high value monomeric constituents, selecting a second higher temperature range to cause pyrolysis of a different high value monomeric constituent of said plastic waste and differentially heating the feedstream at the higher temperature program range to cause pyrolysis of the different high value monomeric constituent; and separating the different high value monomeric constituent.

Evans, Robert J. (Lakewood, CO); Chum, Helena L. (Arvada, CO)

1994-01-01

353

Controlled catalytic and thermal sequential pyrolysis and hydrolysis of mixed polymer waste streams to sequentially recover monomers or other high value products  

Energy Technology Data Exchange (ETDEWEB)

A process of using fast pyrolysis in a carrier gas to convert a plastic waste feedstream having a mixed polymeric composition in a manner such that pyrolysis of a given polymer to its high value monomeric constituent occurs prior to pyrolysis of other plastic components therein comprising: selecting a first temperature program range to cause pyrolysis of said given polymer to its high value monomeric constituent prior to a temperature range that causes pyrolysis of other plastic components; selecting a catalyst and support for treating said feed streams with said catalyst to effect acid or base catalyzed reaction pathways to maximize yield or enhance separation of said high value monomeric constituent in said temperature program range; differentially heating said feed stream at a heat rate within the first temperature program range to provide differential pyrolysis for selective recovery of optimum quantities of the high value monomeric constituent prior to pyrolysis of other plastic components; separating the high value monomeric constituents; selecting a second higher temperature range to cause pyrolysis of a different high value monomeric constituent of said plastic waste and differentially heating the feedstream at the higher temperature program range to cause pyrolysis of the different high value monomeric constituent; and separating the different high value monomeric constituent.

Evans, Robert J. (Lakewood, CO); Chum, Helena L. (Arvada, CO)

1993-01-01

354

Controlled catalytic and thermal sequential pyrolysis and hydrolysis of mixed polymer waste streams to sequentially recover monomers or other high value products  

Energy Technology Data Exchange (ETDEWEB)

A process of using fast pyrolysis in a carrier gas to convert a plastic waste feedstream having a mixed polymeric composition in a manner such that pyrolysis of a given polymer to its high value monomeric constituent occurs prior to pyrolysis of other plastic components therein comprising: selecting a first temperature program range to cause pyrolysis of said given polymer to its high value monomeric constituent prior to a temperature range that causes pyrolysis of other plastic components; selecting a catalyst and support for treating said feed streams with said catalyst to effect acid or base catalyzed reaction pathways to maximize yield or enhance separation of said high value monomeric constituent in said temperature program range; differentially heating said feed stream at a heat rate within the first temperature program range to provide differential pyrolysis for selective recovery of optimum quantities of the high value monomeric constituent prior to pyrolysis of other plastic components; separating the high value monomeric constituents; selecting a second higher temperature range to cause pyrolysis of a different high value monomeric constituent of said plastic waste and differentially heating the feedstream at the higher temperature program range to cause pyrolysis of the different high value monomeric constituent; and separating the different high value monomeric constituent.

Evans, Robert J. (Lakewood, CO); Chum, Helena L. (Arvada, CO)

1994-01-01

355

Microwave pyrolysis for conversion of materials to energy : A review  

International Nuclear Information System (INIS)

Full text: The disposal of wastes in Malaysia is becoming a serious problem in many industrialized and public sectors. This is due to the high production of waste such as municipal solid waste, sludge from waste water treatment plants, agricultural waste and other used non-biodegradable products such as plastics and tyres. These wastes although are reused as compost, fuel, recycled and so on, there are still abundant left. These leftovers pose problems such as heavy metal leaching, leachates, green house gas emissions and mosquito breeding grounds. The disposal cost of these wastes sometimes can be costly at up to RM 2,200/ ton such as petroleum sludge by Kualiti Alam. Several methods have been used to convert these residues to energy via thermal treatment such as combustion, incineration and gasification. However, pyrolysis becomes one of the popular methods as the alternative to the wastes disposal recently. Not only energy (as gas) is produced, by-products such as chemical feedstock and solid absorbent can be produced. The use of microwave for pyrolysis, although relatively new for waste treatment, has several advantages compared to conventional heating. This includes easy control of the heating process, time saving, higher heating efficiency, etc. Tyre microwave pyrolysis plant in UK is known as the earliest plant using microwave technology to breakdown polymer in used tyres. Since 1990s, there are many patents for microwave pyrolysis. The processes are based on microwave pyrolysis of waste include coffee hulls, wood, coal, sewage sludge, hospital waste, plastic wastes, corn cobs and rice straw. The most important factors influencing the yield of product during the pyrolysis is temperature in range from 500 to 1000 degree Celsius according to product preference. High temperature favors gas products; whereas lower temperature favors liquid products. Comparatively, microwave pyrolysis produced gas with higher hydrogen and carbon monoxide (syngas) content compared to conventional heating. Liquid product also showed considerable decrease in polycyclic aromatic hydrocarbons (PAH) production which is of known carcinogenic. Vitrification of heavy metals in solid product has also been proven. (author)

2009-11-03

356

Experimental toxicology of pyrolysis and combustion hazards.  

Science.gov (United States)

Data are presented on the acute toxicity (mortality only) of the thermal degradation products of polymers obtained by two methods of degradation. One system utilized a slowly increasing temperature (5 degrees C/min) and gradual degradation of the polymer with the rats being exposed to degradation products as they were evolved. In this system the more toxic polymers included wool, polypropylene, poly(vinyl chloride), and urethane foam. The second system utilized conditions of rapid combustion and exposure of rats to the total products of combustion for a period of 4 hr. In this system the more toxic materials included red oak, cotton, acrylonitrile-butadiene-styrene (ABS), and styrene-acrylonitrile. It is of interest to note that the natural product wool is among the least toxic under these rapid combustion conditions and among the most toxic under slow pyrolysis conditions. Other materials also vary in the comparative toxicity of their thermal degradation products, depending upon the conditions of degradation and animal exposure. The two experimental techniques presented here may well represent the two extreme conditions of rapid combustion versus slow pyrolysis. Intermediate types of fire situations might be expected to result in relative acute toxicities somewhere between these two extremes. This report deals with acute toxicity on the basis of mortality data only and does not include other parameters of toxicity such as organ weights and histopathology. PMID:1175552

Cornish, H H; Hahn, K J; Barth, M L

1975-06-01

357

Preparation of superconductive films by fume pyrolysis  

Energy Technology Data Exchange (ETDEWEB)

Fine grain films were prepared by fume pyrolysis which can produce particulates having similar diameters. Fumes generated from an aqueous solution of Y, Ba, and Cu nitrates were introduced into the silica tube with flowing O{sub 2}. Fine particles were deposited on the surface of a YSZ substrate placed at the top of the furnace to form a film. Fine particles were deposited for 2 hours in oxygen environment with the temperature inside the reactor tube set at 973K, and then heat treated at 1273K for 5, 10, 15 and 30 minutes. Measurements were performed for resistivity, x-ray diffraction, SEM, EPMA, and AEM. The size of particulates produced by the fume pyrolysis depends on the size of mist drip, and the drip size control results in the control of diameters of particulates. Films of average 5 {mu}m thinness which was annealed at 1273K for 10 minutes showed J{sub c} (critical current) of 100 A/cm{sup 2} when calculated with 100 {mu}A of the current. 8 refs., 7 figs.

Yamada, Seiji; Ogawa, Takao; Miki, Takeshi; Tsuiki, Hideyasu; Kakuta, Noriyoshi; Yamada, Mamoru (Toyohashi Univ. of Tech., Toyohashi (Japan))

1988-12-25

358

UVC emitting phosphors obtained by spray pyrolysis  

Energy Technology Data Exchange (ETDEWEB)

The broadband inter-configurational (4f{sup 1}5d{sup 1{yields}}4f{sup 2}) emission of Pr{sup 3+} doped in lanthanum orthophosphate (LaPO{sub 4}) and in calcium pyrophosphate (Ca{sub 2}P{sub 2}O{sub 7}) has been investigated under plasma excitation. The synthesis by spray pyrolysis at moderate temperature followed by a controlled annealing proves to be a very efficient way to produce good quality UVC emitting phosphor Ca{sub 1.92}Pr{sub 0.04}Na{sub 0.04}P{sub 2}O{sub 7} ({alpha} phase). The emission of this phosphor in the wavelength range 200-350 nm has been measured with a prototype device, which can be employed for anti-microbial testing. - Research Highlights: {yields} The Pr{sup 3+} doped orthophosphate and pyrophosphate were synthesized by spray pyrolysis. {yields} The dense particles present good quality UVC emitting (200-350 nm). {yields} The prototype device can be employed for anti-microbial testing.

Caiut, J.M.A., E-mail: jmacaiut@iq.unesp.b [Centre d' Elaboration de Materiaux et d' Etudes Structurales, CEMES/CNRS-BP 94347, 31055 Toulouse Cedex 4 (France); Institute of Chemistry, UNESP-Universidade Estadual Paulista, CP 355, Araraquara-SP 14801-970 (Brazil); Lechevallier, S.; Dexpert-Ghys, J. [Centre d' Elaboration de Materiaux et d' Etudes Structurales, CEMES/CNRS-BP 94347, 31055 Toulouse Cedex 4 (France); Caillier, B.; Guillot, Ph. [Diagnostic des Plasmas Hors Equilibre, Universite Jean Francois Champollion, place de Verdun, 81012 Albi Cedex 9 (France)

2011-04-15

359

Making Activated Carbon by Wet Pressurized Pyrolysis  

Science.gov (United States)

A wet pressurized pyrolysis (wet carbonization) process has been invented as a means of producing activated carbon from a wide variety of inedible biomass consisting principally of plant wastes. The principal intended use of this activated carbon is room-temperature adsorption of pollutant gases from cooled incinerator exhaust streams. Activated carbon is highly porous and has a large surface area. The surface area depends strongly on the raw material and the production process. Coconut shells and bituminous coal are the primary raw materials that, until now, were converted into activated carbon of commercially acceptable quality by use of traditional production processes that involve activation by use of steam or carbon dioxide. In the wet pressurized pyrolysis process, the plant material is subjected to high pressure and temperature in an aqueous medium in the absence of oxygen for a specified amount of time to break carbon-oxygen bonds in the organic material and modify the structure of the material to obtain large surface area. Plant materials that have been used in demonstrations of the process include inedible parts of wheat, rice, potato, soybean, and tomato plants. The raw plant material is ground and mixed with a specified proportion of water. The mixture is placed in a stirred autoclave, wherein it is pyrolized at a temperature between 450 and 590 F (approximately between 230 and 310 C) and a pressure between 1 and 1.4 kpsi (approximately between 7 and 10 MPa) for a time between 5 minutes and 1 hour. The solid fraction remaining after wet carbonization is dried, then activated at a temperature of 500 F (260 C) in nitrogen gas. The activated carbon thus produced is comparable to commercial activated carbon. It can be used to adsorb oxides of sulfur, oxides of nitrogen, and trace amounts of hydrocarbons, any or all of which can be present in flue gas. Alternatively, the dried solid fraction can be used, even without the activation treatment, to absorb oxides of nitrogen.

Fisher, John W.; Pisharody, Suresh; Wignarajah, K.; Moran, Mark

2006-01-01

360

Virulence prediction of Yersinia enterocolitica by pyrolysis gas-liquid chromatography.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Pyrolysis gas-liquid chromatography (PGLC) was used to differentiate between HeLa cell-invasive and noninvasive strains of Yersinia enterocolitica and between Sereny-positive and -negative strains. A temperature-programmed gas-liquid chromatograph, equipped with a high-resolution Carbowax 20M coated capillary column, separated the volatiles from pyrolyzed whole cells preparations and cell wall fractions. The resulting pyrolysis elution patterns (pyrograms) were divided into 313 30-s time inte...

Stern, N. J.; Kotula, A. W.; Pierson, M. D.

1980-01-01

 
 
 
 
361

Characterisation of the products from pyrolysis of residues after acid hydrolysis of Miscanthus  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Platform chemicals such as furfural and hydroxymethylfurfural are major products formed during the acid hydrolysis of lignocellulosic biomass in second generation biorefining processes. Solid hydrolysis residues (HR) can amount to 50 wt.% of the starting biomass materials. Pyrolysis of the HRs gives rise to biochar, bio-liquids, and gases. Time and temperature were variables during the pyrolysis of HRs in a fixed bed tubular reactor, and both parameters have major influences on the amounts an...

Melligan, F.; Dussan, K.; Auccaise, R.; Novotny, E. H.; Leahy, J. J.; Hayes, M. H. B.; Kwapinski, W.

2012-01-01

362

Heat transfer controlled pyrolysis kinetics of a biomass slab, rod or sphere  

Energy Technology Data Exchange (ETDEWEB)

A theory for deriving the pyrolysis rate of a single infinite slab, infinite cylinder or sphere in a constant temperature furnace is suggested. In analogy with the shrinking-core model a pyrolysis propagation front velocity is defined. The velocity is thereafter used in a compartment-model approach for deriving a set of ordinary differential equations for solving the burn-off over time. A comparison with experimental and published data is also made. (Author)

Liliedahl, Truls; Sjoestroem, Krister [Royal Inst. of Technology, Chemical Engineering and Technology Dept., Stockholm (Sweden)

1998-12-31

363

Characteristics of chars produced by pyrolysis following rapid heating of pulverized coal. [104 references  

Energy Technology Data Exchange (ETDEWEB)

A 5.08-cm id pyrolysis furnace has been used to study pyrolysis following rapid heating of size graded pulverized coal particles as a function of isothermal pyrolysis time (0.018 to 1.025 second), particle size (50 to 181 ..mu..m), and parent coal (three lignites). The following experimental conditions were kept constant: Coal feed rate approximately equal to 0.5 g/min; volumetric flow rate of nitrogen temperature = 808/sup 0/C, and pressure = atmospheric. Under these conditions the heating rate of the coal particles in the pyrolysis furnace was of the order of 8 x 10/sup 3/ /sup 0/C/second. The experimental results show: (i) a monotonic change in the physical properties of chars with increasing pyrolysis time; (ii) some dependence of weight loss (i.e. VM yield) on particle size; (iii) that the three lignites undergo pyrolysis to a comparable extent, presumably because of their similar initial chemical composition; (iv) an appreciable influence of temperature and heating rate on weight loss in the Parr VM crucible; and (v) a significant influence of the mode of pyrolysis (i.e. entrained vs fluid bed) on the nature of the char produced. The results from a theoretical treatment of the problem of gas-solid interactions suggest that, in the pyrolysis furnace, all coal particles smaller than 200 ..mu..m in diameter are heated from their initial room temperature to the predetermined gas temperature of 808/sup 0/C so fast that no appreciable gradient is established between their surface and their center.

Nsakala, N.; Walker, Jr., P. L.; Essenhigh, R. H.

1977-02-01

364

Influence of gas-phase reactions on the product yields obtained in the pyrolysis of polyethylene  

Energy Technology Data Exchange (ETDEWEB)

The amount of plastic wastes is growing year after year, and the fraction of plastics in municipal solid wastes (MSW) and in refuse-derived fuels (RDF) is progressively increasing. Pyrolysis and gasification processes appear to be promising routes for the upgrading of solid wastes to more usable and energy dense materials such as gas fuel and/or fuel oil or to high-value feedstocks for the chemical industry. The characterization of the product fractions obtained from the pyrolysis of polyethylene (PE) in a laboratory-scale fixed bed reactor was performed. The experimental system allowed quantitative information to be obtained on the global tar, char, and gas yields. Pyrolysis runs were performed using reactor temperatures ranging between 500 and 800 C. The influence of the residence times in the reactor of the primary volatiles generated by the pyrolysis process was also discussed. The secondary reactivity of the tar originated from PE pyrolysis was examined. A lumped-parameters approach was used in order to evaluate the global kinetic parameters for the gas-phase tar-cracking process. PE tars resulted to be more refractory to thermal decomposition than those obtained in the pyrolysis of biomass and lignocellulosic materials, but more reactive than tars obtained in the pyrolysis of coal.

Cozzani, V.; Tognotti, L. [Univ. degli Studi di Pisa (Italy); Nicolella, C.; Rovatti, M. [Univ. degli Studi di Genova (Italy). Ist. di Ingegneria Chimica e di Processo G.B. Bonino

1997-02-01

365

Mild pyrolysis of selectively oxidized coals. Technical report, September 1--November 30, 1991  

Energy Technology Data Exchange (ETDEWEB)

The primary objective of this study is to investigate the removal organic sulfur from selectively oxidized Illinois coals using mild thermal/chemical processes. Work completed this quarter includes the investigation of the mild pyrolysis of unoxidized coals plus a selection of selectively oxidized coals. In addition the effect of particle size and extent of oxidation on pyrolysis was investigated. Some preliminary data concerning pyrolysis under vacuum and ambient pressure was also obtained. Work completed this quarter supports the following conclusions: (1) Desulfurization of unoxidized coals increases with increasing pyrolysis temperature and correlates with the loss of volatile matter. (2) Particle size did not influence the extent of desulfurization significantly. (3) Removing pyrite prior to pyrolysis helps to achieve a lower sulfur product beyond that expected from the removal of pyrite alone. (4) The extent of selective oxidation in teh pretreatment step did not effect the level of desulfurization obtained by pyrolysis alone. However this factor was important in the desulfurization obtained with supercritical methanol (SCM)/base. (5) Up to 84% of the sulfur has been removed from the IBC 101 coal by combining selective oxidation and SCM/base reactions. (6) Evidence for regressive reactions between volatilized sulfur compounds and partially desulfurized products was obtained by studying how changes in pyrolysis pressure effected the product sulfur content.

Hippo, E.J.

1991-12-31

366

Catalytic partial oxidation of pyrolysis oils  

Science.gov (United States)

This thesis explores the catalytic partial oxidation (CPO) of pyrolysis oils to syngas and chemicals. First, an exploration of model compounds and their chemistries under CPO conditions is considered. Then CPO experiments of raw pyrolysis oils are detailed. Finally, plans for future development in this field are discussed. In Chapter 2, organic acids such as propionic acid and lactic acid are oxidized to syngas over Pt catalysts. Equilibrium production of syngas can be achieved over Rh-Ce catalysts; alternatively mechanistic evidence is derived using Pt catalysts in a fuel rich mixture. These experiments show that organic acids, present in pyrolysis oils up to 25%, can undergo CPO to syngas or for the production of chemicals. As the fossil fuels industry also provides organic chemicals such as monomers for plastics, the possibility of deriving such species from pyrolysis oils allows for a greater application of the CPO of biomass. However, chemical production is highly dependent on the originating molecular species. As bio oil comprises up to 400 chemicals, it is essential to understand how difficult it would be to develop a pure product stream. Chapter 3 continues the experimentation from Chapter 2, exploring the CPO of another organic functionality: the ester group. These experiments demonstrate that equilibrium syngas production is possible for esters as well as acids in autothermal operation with contact times as low as tau = 10 ms over Rh-based catalysts. Conversion for these experiments and those with organic acids is >98%, demonstrating the high reactivity of oxygenated compounds on noble metal catalysts. Under CPO conditions, esters decompose in a predictable manner: over Pt and with high fuel to oxygen, non-equilibrium products show a similarity to those from related acids. A mechanism is proposed in which ethyl esters thermally decompose to ethylene and an acid, which decarbonylates homogeneously, driven by heat produced at the catalyst surface. Chapter 4 details the catalytic partial oxidation of glycerol without preheat: droplets of glycerol are sprayed directly onto the top of the catalyst bed, where they react autothermally with contact times on the order of tau ? 30 ms. The reactive flash volatilization of glycerol results in equilibrium syngas production over Rh-Ce catalysts. In addition, water can be added to the liquid glycerol, resulting in true autothermal reforming. This highly efficient process can increase H2 yields and alter the H2 to CO ratio, allowing for flexibility in syngas quality depending on the purpose. Chapter 5 details the results of a time on stream experiment, in which optimal syngas conditions are chosen. Although conversion is 100% for 450 hours, these experiments demonstrate the deactivation of the catalyst over time. Deactivation is exhibited by decreases in H2 and CO 2 production accompanied by a steady increase in CO and temperature. These results are explained as a loss of water-gas shift equilibration. SEM images suggest catalyst sintering may play a role; EDS indicates the presence of impurities on the catalyst. In addition, the instability of quartz in the reactor is demonstrated by etching, resulting in a hole in the reactor tube at the end of the experiment. These results suggest prevaporization may be desirable in this application, and that quartz is not a suitable material for the reactive flash volatilization of oxygenated fuels. In Chapter 6, pyrolysis oil samples from three sources - poplar, pine, and hardwoods - are explored in the context of catalytic partial oxidation. Lessons derived from the tests with model compounds are applied to reactor design, resulting in the reactive flash vaporization of bio oils. Syngas is successfully produced, though deactivation due to coke and ash deposition keeps H2 below equlibrium. Coke formation is observed on the reactor walls, but is avoided between the fuel injection site and catalyst by increasing the proximity of these in the reactor design. Low temperatures are maintained in the fuel delivery system utilizing a water-

Rennard, David Carl

367

Pyrolysis of thermally thick wood particles - experiments and mathematical modelling  

Energy Technology Data Exchange (ETDEWEB)

A simple, dynamic, l-dimensional model describing heating, drying and pyrolysis of thermally thick wood particles with a l-dimensional geometry has been developed and implemented. The model output is the dynamic evolution of both the char yield and the amount of volatiles. The model is developed in such a simple and accessible way, that it easily can be implemented in a larger model for dimensioning and optimisation of applications where pyrolysis is a part of the overall process as for instance gasification. Experiments using a Thermo Gravimetric Analyser (TGA), built so pieces of wood can be fed into a hot atmosphere instantaneously, have been used to observe the influence of various parameters like temperature and size and wood types on the pyrolysis process. Results from the model have been compared with results from the experiments. The comparison showed good accordance when both wood particles with a well-defined geometry (a cylinder) and when beds of wood chips and wood pellets, respectively, were pyrolyzed. The model has proven that transport of heat to the wood; internal transport and accumulation of heat inside the wood and kinetics of pyrolysis are all important parameters. (au)

Moeller Andersen, S.; Thaaning Pedersen, S.; Goebel, B.; Houbak, N.; Henriksen, Ulrik [MEK - DTU, Kgs. Lyngby (Denmark); Dall Bentzen, J. [COWI a/s, Kgs. Lyngby (Denmark)

2005-07-01

368

Research into fine powder and large particle tyre pyrolysis.  

Science.gov (United States)

This paper investigates the kinetics of the pyrolysis of scrap tyre using thermogravimetry and a small batch laboratory-scale externally heated fixed-bed. Five particle sizes (20-40, 40-60, 60-80, 80-100, 100-200 mesh) and five heating rates (5, 10, 15, 20, 40 K min(-1)) were investigated. The results show that there is no obvious distinction on weight loss for different sizes. With increasing heating rate the weight loss regions shift to a higher temperature range and the weight loss rate increases. The activation energy (E) and pre-exponential factor constant (A) were calculated using the Arrhenius type kinetic model. The heat value of pyrolysis gases is in the range of 12 to 22 MJ Nm(-3). The yields of solid, liquid and gas of pyrolysis scrap tyre and tyre cube at 800 degrees C were investigated, the ratio of pyrolysis production composition of scrap tyre and tyre cube for gas, oil and char is found to be 35 : 23 : 42 and 10 : 31 : 59, respectively. PMID:19423576

Gao, Ningbo; Li, Aimin; Li, Wanjing

2009-05-01

369

Supercritical pyrolysis of the endothermic fuels methylcyclohexane, decalin, and tetralin  

Science.gov (United States)

The pyrolysis of the potential endothermic fuels methylcyclohexane, decahydronaphthalene (decalin), and tetrahydronaphthalene (tetralin) under supercritical conditions can be of great import and is the focus of this dissertation. Supercritical fluids, essentially gases with a liquid-like density, are a unique environment for chemical kinetic studies. Because the solvent properties of a supercritical fluid vary strongly with pressure (unlike liquids or gases), elementary reactions in a supercritical environment can have strong pressure dependence. The influence of these solute/solvent interactions on kinetic rates can have important implications in the context of the fuel-fouling problem. Supercritical methylcyclohexane pyrolysis was investigated in a specially constructed silica-lined flow reactor. Experiments in which the temperature and pressure were varied independently revealed a product distribution substantially different from numerous higher temperature gas-phase pyrolysis studies. Major products identified at 820 K and 45 atm included methane, ethane, propene, ethene, dimethylcyclopentane, propane, 1-methyl-1-cyclohexene, and ethylcyclopentane. As pressure was increased at 782 K, the selectivity of dimethylcyclopentane increased and was consistent with a mechanism that incorporated caging effects. Some observations related to polycyclic aromatic hydrocarbons (PAH) and solid formation were a natural extension of this research effort. PAH products observed included indene, methylnaphthalenes, dimethylnaphthalenes, fluorene, pyrene, methylanthracene, and benzo[ghi]perylene. A gas-phase model of methylcyclohexane pyrolysis was constructed and compared with experimental data from a sister effort in this laboratory. This model, along with two others currently being developed at Princeton, is the first elementary-reaction-based cycloalkane decomposition model ever created. Excellent agreement was found between the gas-phase model and experimental data for the major products observed. Preliminary steps were taken to extend this model to supercritical conditions through detailed consideration of the solute/solvent interactions present in the supercritical fluid and modifications made to the ideal gas model. Supercritical pyrolysis mechanisms of decalin and tetralin were also investigated. Major products of supercritical decalin pyrolysis included light alkanes and alkenes, methylhexahydroindane, indene, methylcyclohexenes, and indane. Major products of supercritical tetralin pyrolysis included: naphthalene, methylindane, ethane, methane, ethene, and phenylbutane. Quantification of the major products indicated that C6 to C5 ring contraction was found to occur preferentially with increasing pressure, consistent with the caging hypothesis.

Stewart, John Francis

370

Co-pyrolysis and Catalytic Co-pyrolysis of Waste Tyres with Oil Palm Empty Fruit Bunches  

Directory of Open Access Journals (Sweden)

Full Text Available Shredded Waste Tyres (SWT and Shredded Oil Palm Empty Fruit Bunches (SOPEFB were pyrolysed in a fixed bed reactor at 500C with a ratio of 1:1. SWT and impregnated SOPEFB with 10% w/w of cobalt catalyst solution were then pyrolysed in the same reactor at 500oC. The pyrolysed oils were collected in an ice/water condenser. The aim of this work is to study the effects of the addition of cobalt catalyst with direct impregnation into the SOPEFB fibers with respect to the liquid yields. The reactor was externally heated by means of electrical resistance, the heating rate being approximately 30C min-1. Once the required temperature obtained, it was maintained for 2 h. Three phases were obtained after pyrolysis : solid, liquid and gas. Highest yield of liquid product obtained with catalytic co-pyrolysis of SWT and SOPEFB as compared to co-pyrolysis of SWT and SOPEFB. It can be concluded that the catalytic co-pyrolysis using cobalt as catalyst resulted in higher of liquid yield.

K.N. Ismail

2011-01-01

371

Study of mobilization and speciation of trace elements in coal pyrolysis  

International Nuclear Information System (INIS)

Various types of coal contain high levels of a number of trace elements. Little is known of the fates of these trace elements during the conversion of coal to liquid and gaseous products. Studies were undertaken of mobilization and speciation of trace elements in coal pyrolysis, one of the major coal conversion processes. The bituminous coal was pyrolyzed to produce liquid and gaseous products. The pyrolysis products were collected in traps in an inert gas stream. In addition mildly hydrogenated coal was prepared by mixing with tetralin, a hydrogen donor solvent, at boiling temperature. In order to characterize each element specifically during pyrolysis, base samples of coal and mildly hydrogenated coal (H-coal) were spiked with heavy metal sulfides, trace metals bound to partially oxidized coal (coal humates), and halide salts prior to carrying out pyrolysis. Eight elements were investigated in this research. They are As, Br, Cl, Co, Cr, Mn, Se, and V. Pre-spiked hydrogenated coal, i.e., pulverized coal spiked with halide salts and heavy metal sulfides then hydrogenated with tetralin, was prepared and studied for the fates of these elements during pyrolysis. Chlorinated and brominated coals were also prepared to compare the volatility differences between organically and inorganically bound halogens during the pyrolysis reaction. These products and the coal char residues were analyzed for the spiked elements mainly by neutron activation analysis for the spiked elements to determine their degree of volatility. Volatility and recovery (mass balance) will be discussed for those elements that appeared highly volatile during pyrolysis. In order to understand the halogenated compounds in the pyrolysis products, gas chromatograms were taken to the collected pyrolysis products of coal, hydrogenated coal, NaCl spiked coal, NaBr spiked coal, chlorinated coal, and brominated coal

1979-01-01

372

Evaluation of pyrolysis curves for volatile elements in aqueous standards and carbon-containing matrices in electrothermal vaporization inductively coupled plasma mass spectrometry  

International Nuclear Information System (INIS)

Pyrolysis curves in electrothermal atomic absorption spectrometry (ET AAS) and electrothermal vaporization inductively coupled plasma mass spectrometry (ETV-ICP-MS) have been compared for As, Se and Pb in lobster hepatopancreas certified reference material using Pd/Mg as the modifier. The ET AAS pyrolysis curves confirm that the analytes are not lost from the graphite furnace up to a pyrolysis temperature of 800 deg. C. Nevertheless, a downward slope of the pyrolysis curve was observed for these elements in the biological material using ETV-ICP-MS. This could be related to a gain of sensitivity at low pyrolysis temperatures due to the matrix, which can act as carrier and/or promote changes in the plasma ionization equilibrium. Experiments with the addition of ascorbic acid to the aqueous standards confirmed that the higher intensities obtained in ETV-ICP-MS are related to the presence of organic compounds in the slurry. Pyrolysis curves for As, Se and Pb in coal and coal fly ash were also investigated using the same Pd/Mg modifier. Carbon intensities were measured in all samples using different pyrolysis temperatures. It was observed that pyrolysis curves for the three analytes in all slurry samples were similar to the corresponding graphs that show the carbon intensity for the same slurries for pyrolysis temperatures from 200 deg. C up to 1000 deg. C

2008-07-01

373

Deoxygenation and the blood volume signals in the flexor carpi ulnaris and radialis muscles obtained during the execution of the Mirallas's test of judo athletes  

Science.gov (United States)

The technique of execution of any movement in Judo is extremely important. The coaches want tests and tools easy to use and cheaper, to evaluate the progress of a judoist in the tatame. In this paper we present a test developed by Mirallas, which has his name 'Test of Mirallas' to evaluate the maximal power capacity of the judoist. The near infrared spectroscopy (NIRS) signals were obtained to have a measurement of the metabolic work of the flexor carpi ulnaris and radialis muscles, during the execution of the ippon-seoi-nage movement, allowing this measurement to assess by NIRS the maximal oxygen uptake. Also obtained were tympanic, skin forehead, and biceps brachii temperatures during the test time and recovery phase to study the effects of ambient conditions and the post-exercise oxygen consumption. The deoxygenation and blood volume signals obtained gave different results, demonstrating the hypothesis of the coaches that some judoist do the execution of the ippon-seoi-nage movement correctly and the rest didn't. The heart rate frequency obtained in the group of judoist was between 190-207 bpm, and in the minute five of post-exercise was 114-137 bpm; the time employed in the MIrallas's test were from 7 feet 14 inches to 13 feet 49 inches, and the total of movements were from 199 to 409. The data obtained in the skin forehead, and skin biceps brachii confirms previous works that the oxygen consumption remains after exercise in the muscle studied. According to the results, the test developed by Mirallas is a good tool to evaluate the performance of judoist any time, giving better results compared with standard tests.

Verdaguer-Codina, Joan; Mirallas, J.

1996-12-01

374

Fines in fluidized bed silane pyrolysis  

Science.gov (United States)

Silicon deposition on silicon seed particles by silane pyrolysis in a fluidized-bed reactor is investigated as a low-cost, high-throughput method to produce high-purity polysilicon for solar-cell applications. Studies of fines, particles 0.1-10 microns diam, initiated from homogeneous decomposition in the reactor were conducted using 2 and 6-in-diam fluidized beds. The studies show functional dependences of fines elutriation on silane feed concentration, temperature, gas velocity, and bubble size. The observation that the fines elutriation is generally below 10 percent of the silicon-in-silane feed is attributed to scavenging by large particles in an environment of less free space for homogeneous nucleation. Preliminary results suggest that, with proper conditions and distributor design, high-silane-concentration (over 50 percent SiH4 in H2) feed may be used.

Hsu, G.; Hogle, R.; Rohatgi, N.; Morrison, A.

1984-01-01

375

Construction of a Labview controlled pyrolysis unit for coupling to a Pyrola 85 pyrolysis chamber  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Pyrolysis is the process of molecular decomposition in an inert environment using heat. It is possible to fragment large molecules, such as polymers, by pyrolysis and separate the fragments directly in a GC. This makes it possible to form complex sample fingerprints that can be used in various applications, for example in forensic science. In this project, a malfunctioning Pyrola 85 pyrolysis unit was fixed by measuring the voltage signals from the photo diode during pyrolysis in a Labview pr...

O?stman, Marcus; Na?sstro?m, Elin

2012-01-01

376

Gasification and pyrolysis of sewage sludges  

Energy Technology Data Exchange (ETDEWEB)

Gasification and pyrolysis of sewage sludge were examined as alternatives to sewage sludge combustion. For this purpose, experimental gasification and pyrolysis tests were carried out with primary sewage sludge of Emschergenossenschaft. Main objective of these tests was the evaluation of yields and qualities for products gained via sludge gasification or pyrolysis and an assessment of the environmentally relevant properties of the related residues. Both process alternatives enable the utilization of sewage sludge without any negative impact on the environment. Due to the total use of the organic components out of the sewage sludge in combination with an almost complete utilization resulting from the valuable hydrogen produced, gasification is an attractive alternative compared to the burning of sewage sludge, both from an environmental and an economic point of view. In the case of sewage sludge pyrolysis a portion of the organic components, however, will remain in the pyrolysis residue. Therefore, pyrolysis allows only a minor reduction of the residual product.

Wenning, H.P.

1989-04-01

377

Flash pyrolysis of coal through solar heating  

Energy Technology Data Exchange (ETDEWEB)

A laboratory technique for studying flash pyrolysis by radiantly heating small stationary samples of powdered coal with the beam of a carbon dioxide laser is described. With this technique flux levels equivalent to those available from solar furnaces are attainable, experimental parameters are easily controllable and experimental turn around time is short. The pyrolysis of a Western subbituminous coal was studied with laser and solar heating. The pyrolysis products were a gas composed principally of H/sub 2/, CH/sub 4/, CO, and CO/sub 2/, tar, and char. Under laser heating, the gas yield increased with flux up to about 250 W/cm/sup 2/. Under conditions of complete pyrolysis, tar and gas yields were inversely proportional to each other, and char yield was almost constant. Solar coal pyrolysis experiments at the White S