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Jose Corella - One of the best experts on this subject based on the ideXlab platform.
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catalytic Hot Gas Cleaning with monoliths in biomass Gasification in fluidized beds 3 their effectiveness for ammonia elimination
Industrial & Engineering Chemistry Research, 2004Co-Authors: Jose Corella, Jose M Toledo, R PadillaAbstract:Biomasses with relatively high N contents generate a Gasification Gas with a NH3 content between 500 and 6000 ppm, with 2000 ppm of NH3 as the value that can be selected as a reference. This NH3 would generate NOx contents above the legally accepted limits; this is the reason why very often NH3 has to be removed from a Gasification Gas that also contains tar and particulates. The present paper only focuses on the performance of Ni-based monoliths for NH3 elimination from a realistic Gasification Gas coming from a bubbling-fluidized-bed biomass Gasifier, at small pilot-plant scale. Besides using NH3 conversions, analysis of the results was also made using effective kinetic constants (keff) not only for NH3 but also for the simultaneous and competitive tar removal reaction. Correlations were found between the keff,NH3 and keff,tar values, included in effective Sherwood numbers, and the Reynolds and Schmidt numbers, the pitch of the channels of the monolith, and the temperature. The effect of the temperature...
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Catalytic Hot Gas Cleaning with Monoliths in Biomass Gasification in Fluidized Beds. 2. Modeling of the Monolithic Reactor
Industrial & Engineering Chemistry Research, 2004Co-Authors: Jose Corella, Jose M Toledo, Rafael A. Araque PadillaAbstract:Nickel-containing monoliths can be used to eliminate tar and ammonia in a real biomass Gasification Gas. They can work with a fuel Gas containing important amounts of particulates, as in the case of the fuel Gas produced in fluidized-bed Gasifiers. The use of monoliths is a very recent and promising technology that has not yet reached a commercial level and requires experimental studies at pilot scale. Those studies indicate that tar and ammonia conversions (eliminations) with these monoliths depend on so many experimental variables that a model is needed to understand and correlate the results obtained with these monolithic reactors. A model is developed in this paper for the monolithic reactor that has two very different zones: the Gas reheating zone and the monolith itself. The model is developed according to the basic rules of chemical reaction engineering, and it includes two microkinetic models for the tar and NH3 elimination reactions, mass balances for tar and NH3, and a heat balance in the monol...
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commercial steam reforming catalysts to improve biomass Gasification with steam oxygen mixtures 1 Hot Gas upgrading by the catalytic reactor
Industrial & Engineering Chemistry Research, 1997Co-Authors: Miguel A Caballero, Juan A Martin, Maria P Aznar, Javier Gil, Eva Frances, Jose CorellaAbstract:Commercial steam reforming (nickel-based) catalysts are used for Hot Gas Cleaning and upgrading in biomass Gasification with steam−oxygen mixtures. The Gasifier used was an atmospheric and bubbling fluidized bed with an internal diameter of 15 cm and a total height of 3.2 m and was continuously fed with 5−20 kg of biomass/h. Eight different catalysts from four different manufacturers (BASF AG, TOPSOE A/S, ICI, and UCI) have been tested. They were located in a downflow fixed-bed reactor of 4 cm i.d. placed in a slip flow after the Gasifier. A guard bed with a calcined dolomite was also used before the catalytic bed to decrease the tar content in the raw Gas below the limit of 2 g of tar/m3n, thus avoiding the catalyst deactivation by coke formation. The main variables studied were the temperature of the catalytic bed and the Gas composition in the bed. Effects concerning tar elimination will be reported in part 2 of this work. This paper is mainly devoted to characterization of catalysts and to upgrading o...
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Hot Gas Cleaning and upgrading with a calcined dolomite located downstream a biomass fluidized bed Gasifier operating with steam oxygen mixtures
Energy & Fuels, 1997Co-Authors: P. Pérez, P M Aznar, Juan A Martin, Miguel A Caballero, Jose CorellaAbstract:Cleaning and upgrading of the Hot raw Gas from a biomass Gasifier, bubbling fluidized bed type, is studied at small pilot plant scale (10 kg biomass fed/h) using a calcined dolomite located downstream from the Gasifier. Gasification is made with steam−oxygen mixtures at 800−850 °C and atmospheric pressure. Main variables studied are the Gas residence time in the bed of dolomite and the Gas atmosphere composition, which depends on the Gasifying agent (H2O + O2)-to-biomass and H2O/O2 ratios. H2 and CO content in the flue Gas increases by 16−23 vol % and decreases by 15−22 vol % (dry basis), respectively. Although CH4 conversion (elimination) higher than 30 vol % has never been reached, tar conversion (elimination) of 90−95 vol % are obtained with space times of 0.06−0.15 kg calcined dolomite h-1 m-3. A detailed study is here presented on how the calcined dolomite significantly cleans and upgrades the flue Gas, increasing also the Gas yield by 0.15−0.40 m3(STP)/kg daf biomass fed.
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Characterization and Activity of Different Dolomites for Hot Gas Cleaning in Biomass Gasification
Developments in Thermochemical Biomass Conversion, 1997Co-Authors: A. Orío, Jose Corella, I. NarváezAbstract:The aim of this work is to identify if the type, origin or composition of the calcined dolomite has some influence on its activity for tar elimination in a Hot flue Gas coming from a biomass Gasifier, bubbling fluidized bed type. For this purpose four different dolomites from four different quarries and Companies have been studied. Chemical analysis, adsorption isotherms, surface and pore size distributions both with nitrogen and by mercury porosimetry, etc,... have been made for three different samples of each dolomite. Activity tests for fresh tar destruction have been simultaneously carried out for each type of calcined dolomite in a fixed bed of 6 cm i.d. The tar elimination activity of the dolomite and the product distribution from it seem do not depend much on the composition or type of the dolomite used.
Pekka Simell - One of the best experts on this subject based on the ideXlab platform.
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sulphur poisoning of nickel based Hot Gas Cleaning catalysts in synthetic Gasification Gas i effect of different process parameters
Applied Catalysis B-environmental, 1997Co-Authors: Jouko Hepola, Pekka SimellAbstract:Abstract The effect of different process parameters on sulphur poisoning of nickel catalysts in tar (toluene), ammonia and methane decomposition was studied. Tests were carried out in a fixed-bed tube reactor at 800–1000°C at 5 and under 20 bar total pressure using a synthetic Gasification Gas mixture. In the same conditions, sulphur affected less the toluene and methane decomposing activity than the ammonia decomposing activity. Ammonia conversion was affected by the catalyst type but not by the nickel content of catalyst. When temperature was increased the effect of sulphur poisoning was decreased. At 20 bar pressure the poisoning effect of sulphur was stronger than at 5 bar pressure. To prevent sulphur poisoning of nickel catalysts in the tar and ammonia decomposition process at high pressure (20–30 bar), the catalyst process should operate at > 900°C. In addition, by decreasing the space velocity of the process the sulphur poisoning effect could be compensated in the test conditions.
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sulphur poisoning of nickel based Hot Gas Cleaning catalysts in synthetic Gasification Gas ii chemisorption of hydrogen sulphide
Applied Catalysis B-environmental, 1997Co-Authors: Jouko Hepola, Pekka SimellAbstract:The effect of different components of Gasification Gas on sulphur poisoning of nickel catalysts were studied. In addition, the sulphur distribution and content of nickel catalyst beds were analysed to account the poisoning effect of sulphur on the activity of catalysts to decompose tar, ammonia and methane. The desorption behaviour of chemisorbed sulphur from the bed materials was monitored by temperature programmed hydrogenation (TPH). It was established that bulk nickel sulphide was active in decomposing ammonia in high-temperature Gasification Gas-Cleaning conditions. The decomposing activity of methane was not affected by bulk nickel sulphide formation, but that of toluene was decreased. The activity of the catalyst regained rapidly when H2S was removed from the Gas. However, the conversion of ammonia was not regained at as high a level as before sulphur addition, most probably due to irreversible sulphur adsorption on the catalyst. The temperature increase could also be used to regenerate the catalyst performance especially in respect to methane and toluene. Sulphur adsorbed on nickel catalysts in different chemical states depends on the process conditions applied. At >900°C the sulphur adsorbed on the catalyst formed an irreversible monolayer on the catalyst surfaces, while at <900°C the adsorbed sulphur, probably composed of polysulphides (multilayer sulphur), was desorbed from the catalyst in sulphur-free hydrogen containing atmosphere. However, a monolayer of sulphur still remained on the catalyst after desorption. The enhanced effect of high total pressure on sulphur-poisoning of nickel catalysts could be accounted for the increased amount of sulphur, probably as a mode of polysulphides, adsorbed on the catalyst.
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Gasification Gas Cleaning with nickel monolith catalyst
1997Co-Authors: Pekka Simell, Pekka Stahlberg, Jouko Hepola, Yrjo Solantausta, Esa KurkelaAbstract:Particulate-containing Gas derived from fluidized-bed biomass Gasification can be efficiently purified from tars and ammonia by using a nickel monolith catalyst. Catalyst deactivation by H2S and carbon deposition can be avoided at 20 bar pressure by using temperatures over 900 °C. Catalyst deactivation was not observed in a long-term test that lasted 500 h. According to a techno-economical evaluation catalytic Hot Gas Cleaning is economically equal to ammonia removal by SCR in an 60 MWe IGCC plant.
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Sulfur poisoning of nickel-based Hot Gas Cleaning catalysts in synthetic Gasification Gas
Catalyst Deactivation Proceedings of the 7th International Symposium, 1997Co-Authors: Jouko Hepola, Pekka SimellAbstract:The sulfur distribution and content of nickel catalyst beds were analyzed to account for poisoning effects of sulfur on the activities of catalysts which decompose tar, ammonia and methane in synthetic Gasification Gas. The desorption behavior of chemisorbed sulfur from the bed materials was monitored by temperature programmed hydrogenation (TPH). Sulfur adsorbs on nickel catalysts in different chemical states depending on the process conditions. At>900°C the sulfur adsorbs on the catalyst forming an irreversible monolayer on catalyst surfaces, while at
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catalytic Hot Gas Cleaning of Gasification Gas
Catalysis Today, 1996Co-Authors: Pekka Simell, Pekka Stahlberg, Esa Kurkela, Jouko HepolaAbstract:Abstract Gasification Gas containing dust can be efficiently purified from tars and ammonia with nickel monolith catalyst. Temperatures over 900°C and residence times of about 1 s (SV 2500 1/h) were needed at 5 bar pressure to obtain complete tar decomposition and 80% ammonia conversion with a feed Gas from a pilot scale fluidized bed Gasifier. At these conditions deactivation caused by carbon deposition or by H 2 S can be avoided. Decline of catalyst activity was not observed during 100 h long test runs. Dolomites and limestones can be used as effective tar decomposing catalysts at lower pressures and around 900°C temperatures, where they stay in calcined form. Low-cost iron containing materials can in turn be applied for catalytic ammonia removal.
Jouko Hepola - One of the best experts on this subject based on the ideXlab platform.
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Sulfur transformations in catalytic Hot-Gas Cleaning of Gasification Gas
2000Co-Authors: Jouko HepolaAbstract:The aim of the present work was to obtain new knowledge on the poisoning effects of sulfur on nickel catalysts used for tar and ammonia decomposition in Gasification Gas. Catalyst performance tests and sulfur poisoning tests were carried out in atmospheric and pressurized fixed-bed tube reactors and in a pressurized honeycomb reactor. The desorption behavior of chemisorbed sulfur from the bed materials was monitored using temperature-programmed hydrogenation. A closed-loop Gas-recirculation system was used to measure the isosteric heat of sulfur chemisorption on supported nickel catalysts under HotGas Cleaning conditions. Under the same conditions, sulfur affected the hydrocarbon (tar, methane)decomposing activity less than the ammonia decomposing activity. When the temperature was increased or the total pressure decreased, the effect of sulfur poisoning likewise decreased. To prevent sulfur poisoning of nickel catalysts in tar and ammonia decomposition, the catalytic process should operate at temperatures above 1173 K. It turned out that bulk nickel sulfide was active in decomposing ammonia under high-temperature Gasification Gas-Cleaning conditions. The methane decomposing activity of the catalyst, however, was not affected by bulk nickel sulfide formation under pressurized conditions, but that of toluene clearly decreased. The activity of the catalyst in ammonia decomposing already increased before the H2S concentration in the Gas phase reached the bulk nickel sulfide formation limit. This activity change caused by adsorbed sulfur species, therefore, was not related to the phase change only but was explained by the decrease in enthalpy resulting from sulfur chemisorption on nickel. The dissociative adsorption of ammonia is probably facilitated on the nickel surfaces when the binding energy of sulfur on nickel decreases. Sulfur was adsorbed on nickel catalysts in different chemical states, depending on the process conditions applied. In high-temperature Gasification Gas
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Elucidation of behavior of sulfur on nickel-based Hot Gas Cleaning catalysts
Applied Catalysis B: Environmental, 1999Co-Authors: Jouko Hepola, Jon G. Mccarty, Gopala N. Krishnan, Victor L. WongAbstract:A closed-loop Gas-recirculation system was used to measure the isosteric heat of sulfur chemisorption on supported nickel catalysts in Hot Gas Cleaning conditions of Gasification Gas. During sulfur adsorption, reconstruction of the catalysts occurred. In addition, probably the enormous increase in surface diffusion due to sulfur adsorption on some nickel catalysts with high flow rates resulted in melt formation of adsorbed species on the surfaces of catalyst particles. Heat of sulfur adsorption on nickel decreased when sulfur coverage was increased. However, the enthalpy of adsorption decreased even below the heat of formation of bulk Ni3S2, indicating most likely multi-layer or subsurface sulfur formation on catalyst surfaces. The structural properties of the catalysts had a great influence on sulfur adsorption behavior. The effect of sulfur on ammonia decomposition in synthetic Gasification Gas tests was explained by the change of heat of sulfur chemisorption on nickel.
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sulphur poisoning of nickel based Hot Gas Cleaning catalysts in synthetic Gasification Gas ii chemisorption of hydrogen sulphide
Applied Catalysis B-environmental, 1997Co-Authors: Jouko Hepola, Pekka SimellAbstract:The effect of different components of Gasification Gas on sulphur poisoning of nickel catalysts were studied. In addition, the sulphur distribution and content of nickel catalyst beds were analysed to account the poisoning effect of sulphur on the activity of catalysts to decompose tar, ammonia and methane. The desorption behaviour of chemisorbed sulphur from the bed materials was monitored by temperature programmed hydrogenation (TPH). It was established that bulk nickel sulphide was active in decomposing ammonia in high-temperature Gasification Gas-Cleaning conditions. The decomposing activity of methane was not affected by bulk nickel sulphide formation, but that of toluene was decreased. The activity of the catalyst regained rapidly when H2S was removed from the Gas. However, the conversion of ammonia was not regained at as high a level as before sulphur addition, most probably due to irreversible sulphur adsorption on the catalyst. The temperature increase could also be used to regenerate the catalyst performance especially in respect to methane and toluene. Sulphur adsorbed on nickel catalysts in different chemical states depends on the process conditions applied. At >900°C the sulphur adsorbed on the catalyst formed an irreversible monolayer on the catalyst surfaces, while at <900°C the adsorbed sulphur, probably composed of polysulphides (multilayer sulphur), was desorbed from the catalyst in sulphur-free hydrogen containing atmosphere. However, a monolayer of sulphur still remained on the catalyst after desorption. The enhanced effect of high total pressure on sulphur-poisoning of nickel catalysts could be accounted for the increased amount of sulphur, probably as a mode of polysulphides, adsorbed on the catalyst.
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sulphur poisoning of nickel based Hot Gas Cleaning catalysts in synthetic Gasification Gas i effect of different process parameters
Applied Catalysis B-environmental, 1997Co-Authors: Jouko Hepola, Pekka SimellAbstract:Abstract The effect of different process parameters on sulphur poisoning of nickel catalysts in tar (toluene), ammonia and methane decomposition was studied. Tests were carried out in a fixed-bed tube reactor at 800–1000°C at 5 and under 20 bar total pressure using a synthetic Gasification Gas mixture. In the same conditions, sulphur affected less the toluene and methane decomposing activity than the ammonia decomposing activity. Ammonia conversion was affected by the catalyst type but not by the nickel content of catalyst. When temperature was increased the effect of sulphur poisoning was decreased. At 20 bar pressure the poisoning effect of sulphur was stronger than at 5 bar pressure. To prevent sulphur poisoning of nickel catalysts in the tar and ammonia decomposition process at high pressure (20–30 bar), the catalyst process should operate at > 900°C. In addition, by decreasing the space velocity of the process the sulphur poisoning effect could be compensated in the test conditions.
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Gasification Gas Cleaning with nickel monolith catalyst
1997Co-Authors: Pekka Simell, Pekka Stahlberg, Jouko Hepola, Yrjo Solantausta, Esa KurkelaAbstract:Particulate-containing Gas derived from fluidized-bed biomass Gasification can be efficiently purified from tars and ammonia by using a nickel monolith catalyst. Catalyst deactivation by H2S and carbon deposition can be avoided at 20 bar pressure by using temperatures over 900 °C. Catalyst deactivation was not observed in a long-term test that lasted 500 h. According to a techno-economical evaluation catalytic Hot Gas Cleaning is economically equal to ammonia removal by SCR in an 60 MWe IGCC plant.
Kung-yuh Chiang - One of the best experts on this subject based on the ideXlab platform.
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Hydrogen production enhancement using Hot Gas Cleaning system combined with prepared Ni-based catalyst in biomass Gasification
International Journal of Hydrogen Energy, 2021Co-Authors: Thi Ngoc Lan Thao Ngo, Kung-yuh Chiang, Chiung-fang Liu, Ying-his Chang, Wan Hou-pengAbstract:Abstract This paper investigates the Hot Gas temperature effect on enhancing hydrogen generation and minimizing tar yield using zeolite and prepared Ni-based catalysts in rice straw Gasification. Results obtained from this work have shown that increasing Hot Gas temperature and applying catalysts can enhance energy yield efficiency. When zeolite catalyst and Hot Gas temperature were adjusted from 250 °C to 400 °C, H2 and CO increased slightly from 7.31% to 14.57%–8.03% and 17.34%, respectively. The tar removal efficiency varies in the 70%–90% range. When the zeolite was replaced with prepared Ni-based catalysts and Hot Gas Cleaning (HGC) operated at 250 °C, H2 contents were significantly increased from 6.63% to 12.24% resulting in decreasing the hydrocarbon (tar), and methane content. This implied that NiO could promote the water-Gas shift reaction and CH4 reforming reaction. Under other conditions in which the Hot Gas temperature was 400 °C, deactivated effects on prepared Ni-based catalyst were observed for inhibiting synGas and tar reduction in the HGC system. The prepared Ni-based catalyst worked at 250 °C demonstrate higher stability, catalyst activity, and less coke decomposition in dry reforming. In summary, the optimum catalytic performance in synGas production and tar elimination was achieved when the catalytic temperature was 250 °C in the presence of prepared Ni-based catalysts, producing 5.92 MJ/kg of lower heating value (LHV) and 73.9% tar removal efficiency.
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The migration, transformation and control of trace metals during the Gasification of rice straw.
Chemosphere, 2020Co-Authors: Ngo Thi Ngoc Lan Thao, Kung-yuh ChiangAbstract:Abstract This research investigates the trace metals speciation, partitioning and removal in rice straw Gasification equipped with an integrated Hot Gas Cleaning (HGC) system. The experiments were conducted by fluidized bed Gasifier and controlled at 800 °C with equivalence ratio (ER) varied between 0.2 and 0.4. The experimental results indicated that the concerned trace metals Zn, Cr, Cd, and Pb partitioning in the Gas phase were increased significantly with an increase in ER. This is because the exothermic reaction could enhance the trace metals reacted with chlorine and/or sulfur as well as correspondingly formed highly volatile metals compounds. However, other tested metals Cu, Na, K, Ca, Mg partitioning was obviously decreased in the Gas phase with ER increasing. These tested metals tend to form oxides speciation leading the variation in their partitioning characteristics. The XRD identification and thermodynamic equilibrium simulation results were also confirmed the tested metals speciation and partitioning characteristics. The dominant Gaseous species produced from rice straw Gasification, such as KCl(g), NaCl(g), KO(g), K2O(g), ZnCl2(g), CrO2Cl2(g), CuCl2(g), PbCl2(g), PbO(g), and Cd(g), were predicted by thermodynamic equilibrium model. The tested metals removal by adsorbents of Hot Gas Cleaning system was found to be adsorbed in decreasing order as: K > Cr > Ca > Pb > Mg > Cd > Na > Zn > Cu. Activated carbon was used in Hot Gas Cleaning system and showed a good performance for adsorbing tested metals, especially for Pb, Cd, Cr, Ca, K, and Mg. In summary, HGC system is proposed as an effective way for improving the synGas quality and reducing trace contaminants emission in rice straw Gasification.
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Enhanced trace pollutants removal efficiency and hydrogen production in rice straw Gasification using Hot Gas Cleaning system
International Journal of Hydrogen Energy, 2019Co-Authors: Ngo Thi Ngoc Lan Thao, Kung-yuh Chiang, Wan Hou-peng, Hung Wei-chun, Chiung-fang LiuAbstract:Abstract This study investigates the enhancement of tar and trace Gaseous pollutants (e.g. hydrogen sulfide (H2S) and hydrogen chloride (HCl) removal efficiency derived from rice straw Gasification using an integrated Hot-Gas Cleaning system. A bubbling fluidized bed Gasifier was used by controlling the temperature at 800 °C and equivalence ratio (ER) ranging 0.2 to 0.4. The Hot Gas Cleaning system was operated at 250 °C and designed to combine three types of absorbents including zeolite, calcined dolomite, and activated carbon. Tar, H2S, and HCl removal efficiency and enhanced hydrogen production were also discussed. The experimental results indicated that light fraction tar removal efficiency was higher than 90% and the overall tar removal efficiency was approximately 70%. In the case of ER 0.4, the synGas tar content was decreased from 71.88 g/Nm3 (without Hot Gas Cleaning system) to 16.53 g/Nm3 (with Hot Gas Cleaning system). The tar removal efficiency is nearly 77% using the Hot Gas Cleaning system. The HCl and H2S removal efficiency ranged from 94% to 98% and from 80.7% to 83.92%, respectively. In the case of ER 0.3 and with the Hot Gas Cleaning system, the HCl and H2S concentrations in cleaned synGas Gas were less than 40 ppm and 100 ppm, respectively. Meanwhile, the hydrogen concentration of produced Gas was also increased from 6.82% to 9.83% with Hot Gas Cleaning system used. It means that the Hot Gas Cleaning system can effectively remove HCl and H2S from produced Gas in Gasification, but also it has good potential for improving synGas quality and enhancing Gas turbine application in the future.
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Improving the Synthesis Gas Quality in Catalytic Gasification of Rice Straw by an Integrated Hot-Gas Cleaning System
International Journal of Green Energy, 2014Co-Authors: Kung-yuh Chiang, Ming-hui Lin, Kuang-li Chien, Yun-his LinAbstract:This research investigates an enhanced removal rate of tar and trace pollutants (e.g. hydrogen chloride and hydrogen sulfide, H2S) in the Gasification of rice straw, using an integrated in situ tar reduction and Hot-Gas Cleaning technique. The Gasification temperature was set at 900°C and equilibrium ratio (ER) was 0.30 in the Gasifier. In the in situ tar reduction method, the catalyst, dolomite with an amended ratio of 0–15% was introduced to the Gasifier. The integrated Hot-Gas Cleaning system applied a multi-packed tower to remove the tar, sulfur and/or chlorine byproduct in synGas at 250°C. The packed materials composed of zeolite, calcined dolomite and activated carbon. The experimental results indicated that the tar concentration of synGas was approximately 20 g/kg. However, in catalytic Gasification with 5% dolomite addition, the tar concentration reduced to 17 g/kg. The tar reduction efficiency was approximately 15% by an in situ dolomite addition. When applying the integrated Hot-Gas cleanup syst...
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Reducing tar yield in Gasification of paper-reject sludge by using a Hot-Gas Cleaning system
Energy, 2013Co-Authors: Kung-yuh Chiang, Ming-hui Lin, Kuang-li ChienAbstract:A new tar destruction technology has been developed by integrating in-situ catalytic Gasification and a Hot-Gas Cleaning system in the catalytic Gasification of paper-reject sludge. Experimental results indicated that the tar yield in synGas decreased significantly from 13.64 to 10.76 g/m3, when increasing the zeolite addition during in-situ catalytic Gasification. When the synGas passed through the Hot-Gas Cleaning system, the tar concentration measured from downstream was approximately 0.22 g/m3. The Hot-Gas Cleaning system used in this research seems to have played a significant role in reducing tar concentration of the synGas. The major tar speciation identified after Hot-Gas Cleaning system was 1-ring or 2-ring hydrocarbons, which included benzene, toluene, xylene, styrene and naphthalene. In summary, the energy yield efficiency of synGas will be enhanced due to the tar reduction and transformation. The synGas seems to be appropriate to use as a fuel in Gas engines for electricity generation.
Miguel A Caballero - One of the best experts on this subject based on the ideXlab platform.
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commercial steam reforming catalysts to improve biomass Gasification with steam oxygen mixtures 1 Hot Gas upgrading by the catalytic reactor
Industrial & Engineering Chemistry Research, 1997Co-Authors: Miguel A Caballero, Juan A Martin, Maria P Aznar, Javier Gil, Eva Frances, Jose CorellaAbstract:Commercial steam reforming (nickel-based) catalysts are used for Hot Gas Cleaning and upgrading in biomass Gasification with steam−oxygen mixtures. The Gasifier used was an atmospheric and bubbling fluidized bed with an internal diameter of 15 cm and a total height of 3.2 m and was continuously fed with 5−20 kg of biomass/h. Eight different catalysts from four different manufacturers (BASF AG, TOPSOE A/S, ICI, and UCI) have been tested. They were located in a downflow fixed-bed reactor of 4 cm i.d. placed in a slip flow after the Gasifier. A guard bed with a calcined dolomite was also used before the catalytic bed to decrease the tar content in the raw Gas below the limit of 2 g of tar/m3n, thus avoiding the catalyst deactivation by coke formation. The main variables studied were the temperature of the catalytic bed and the Gas composition in the bed. Effects concerning tar elimination will be reported in part 2 of this work. This paper is mainly devoted to characterization of catalysts and to upgrading o...
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Hot Gas Cleaning and upgrading with a calcined dolomite located downstream a biomass fluidized bed Gasifier operating with steam oxygen mixtures
Energy & Fuels, 1997Co-Authors: P. Pérez, P M Aznar, Juan A Martin, Miguel A Caballero, Jose CorellaAbstract:Cleaning and upgrading of the Hot raw Gas from a biomass Gasifier, bubbling fluidized bed type, is studied at small pilot plant scale (10 kg biomass fed/h) using a calcined dolomite located downstream from the Gasifier. Gasification is made with steam−oxygen mixtures at 800−850 °C and atmospheric pressure. Main variables studied are the Gas residence time in the bed of dolomite and the Gas atmosphere composition, which depends on the Gasifying agent (H2O + O2)-to-biomass and H2O/O2 ratios. H2 and CO content in the flue Gas increases by 16−23 vol % and decreases by 15−22 vol % (dry basis), respectively. Although CH4 conversion (elimination) higher than 30 vol % has never been reached, tar conversion (elimination) of 90−95 vol % are obtained with space times of 0.06−0.15 kg calcined dolomite h-1 m-3. A detailed study is here presented on how the calcined dolomite significantly cleans and upgrades the flue Gas, increasing also the Gas yield by 0.15−0.40 m3(STP)/kg daf biomass fed.