- Email: [email protected]
CeO2
03 (average value of x = 2) and Hz. The main route to COz reduction occurs via initial formation of carbonate close to the metal-support boundary. Carbon on the metal reduces that carbonate to formate by forming CO. The formate decomposes rapidly to CO and a surface hydroxyl group. Hydroxyl groups recombine and form water or react further with methane to CO and hydrogen. When the rate of methane decomposition and carbonate reduction are in balance, the catalytic activity remains stable. In contrast, the activity of rhodium is mainly determined by the concentration of accessible surface atoms and a concerted metal catalysed mechanism of methane decomposition and subsequent COz reduction dominates.
New clean fuel from coal - direct dlmethyl ether QQlW354 synthesis from hydrogen and carbon monoxide Ogawa, T. et al. Proc. Annu. Int. Pittsburgh Coal Conf., 1997, 14, (30), 1526. For the direct production of Me20 by hydrogenation of CO at 533-553 K and 3-5 MPa using newly developed catalysts a process is presented.
Numerical and experimental 99/06355 jetting fluldized bed coal gaslfler
lnvestlgatlon
on a
Bi, J. et al. Proc. Annu. Int. Pittsburgh Coal Conf., 1997, 14, (20), 1-5. For a jetting fluidized bed coal gasifier with a conical distributor a numerical simulation study was conducted. This study was based on a steady-state model which took account of hydrodynamics, mass transfer, heat transfer and reactions in the grid zone, bubble zone and freeboard zone of the gasifier. Temperatures of the particle and gas in the jet, compositions in the bed, and some hydrodynamic characteristics were calculated. Effects of some operating conditions such as oxygen, steam flow rates, bed pressure and bed temperature on the temperatures in jet and gas compositions in the gasifier were numerically investigated. Temperature profiles of the particles and gas in the jet, and gas compositions in the bed were compared between the simulation and experiments carried out in a laboratory scale gasifier.
Partial oxidation of methane to syngas over Nil MgO, NllCaO and NI/Ce02
Gaseous fuels (derived gaseous fuels)
composition was CH4 3.6 wt%, C&d hydrocarbons 1.4 wt%, Hz 0.8 wt% and CO + CO2 96 wt%; the heating value of this gas was only 204 BTU/ SCF. These results show that char obtained during catalytic upgrading is extremely reactive and produces high yields of Hz and hydrocarbons. On the other hand, vacuum char is not so reactive and produces high yields of CO and COz. These results suggest that catalytic char is capable of producing a high BTU gas by simple steam gasification alone. QQlW359
A pressurized reactor with Integrated load cell for measuring the activities of Fischer-Tropschtatalysts and their loadings with llquld reactlon products (wax)
Raak, H. and Hedden, K. Erdoel, Erdgas, Kohle, 1998, 114, (5), 251-256. (In German) The Fischer-Tropsch synthesis is the heterogeneously catalysed hydrogenation of carbon monoxide with the objective of producing long-chain hydrocarbons. Particularly in countries with large natural gas reserves in geographically unfavourable fringe locations, it provides an alternative to the liquefaction of natural gas. The concept for a low-cost process for the conversion of natural gas to liquid hydrocarbons was elaborated in a joint project of the universities of Karlsruhe and Qatar. The following article surveys some results of a doctoral dissertation, which within the framework of this joint project deals with kinetic investigations in the start-up phase of the Fischer-Tropsch synthesis. The tests were carried out with a technologically precipitated iron catalyst of the Lurgi/Ruhrchemie joint venture at temperatures between 200 and 250” and with a reaction pressure of 20 bar. Under reaction conditions it was possible to show that the pore system of the catalyst is completely filled with higher hydrocarbons (wax) during the first hours of the synthesis. After this period the wax content of the catalyst is approximately 32 wt%. The interrelation between the activity of the catalyst and its load with liquid reaction products was examined with the aid of a pressurized reactor with an integrated load cell. This paper describes the measuring method and some experimental results, in particular the mass transfer limitations that occurred in the catalyst pores.
QQlQCl356
Tang, S. et al. Catal. Lett., 1998, 51, (3,4), 169-175. Over Ni/MgO, Ni/CaO and Ni/CeOz catalysts with nickel loading of 13 wt% partial oxidation of methane to syngas at atmospheric pressure and 750°C was examined. All catalysts had similar high conversion of methane and high selectivity to syngas, which nearly approached the values predicted by thermodynamic equilibrium. However, only Ni/MgO showed high resistance to carbon deposition under thermodynamically severe conditions. Its catalytic activity remained stable during 100 h of reaction, with no detectable carbon deposition. With an in-situ TPO-MS study, the oxidation of carbon deposited from pure CH., decomposition and from pure CO disproportionation was investigated: it showed that both were effectively inhibited over Ni/MgO. In addition, the catalysts were characterized by TPR, XRD and XPS. The excellent performance of Ni/MgO resulted from the formation of an ideal solid solution between NiO and MgO.
hydrocarbon Petroleum anaerobic laboratory aquifer columns
QQiQQ357
mineralization
in
Hunkeler, D. et al. J. Contam. Hydrol., 1998, 32, (l-2), 41-61. As a naturally occurring remediation process, anaerobic biodegradation of hydrocarbons at mineral oil-polluted sites has gathered increasing interest. Hydrocarbon biodegradation in laboratory aquifer columns in the absence of Oz and NOs was studied to calculate a mass balance of the anaerobic biodegradation processes. Laboratory columns containing aquifer material from a diesel fuel-polluted aquifer were operated at 25” for 65 days with artificial groundwater containing only S04’- and CO* as externally supplied oxidants. After 31 days of column operation, stable concentration profiles were observed for most of the measured dissolved species. In the column, nalkanes were selectively removed while branched alkanes persisted, suggesting a biological degradation. Furthermore, based on changes in concentrations of aromatic compounds with similar physicochemical properties in the effluent, it was concluded that toluene, p-xylene, and naphthalene were degraded. A carbon mass balance showed that 65% of hydrocarbons removed from the column were recovered as DIC; 20% were recovered as CH+ and 15% were eluted from the column. Calculations indicated that hydrocarbon mineralization coupled to S04’- reduction and methanogenesis contributed in equal proportions to hydrocarbon removal. Hydrocarbon mineralization coupled to Fe3+ and Mn4+ reduction was of minor importance.
Potential of producing high BTU gas from various QQiO6356 biomass-derived chars
Idem, R. 0. et al. Making Bus. Biomass Energy, Environ., Chemical, Fibers Mater., Proc. Biomass Conf. Am. 3rd, 1997, (1) 383-390. Edited by Overend, R. P. and Chornet, E. In an Inconel-alloy microreactor at a steam rate of 10 g/h using chars obtained from two processes steam gasification of char was conducted at temperatures of 600, 700 and 800”. The first process was the char obtained from bio-oil upgrading using HZSM-5 catalyst (i.e. catalytic char) and the second was the char obtained from vacuum distillation of bio-oil (i.e. vacuum char). At 800”, conversion of catalytic char was very high (close to 84 wt%) and produced a gas which had a heating value of 931 BTU/SCF (methane has a heating value of 1000 BTU/SCF). On the other hand, conversion of the vacuum char at 800” was 60 wt%. The product
QQlQO369
Process and catalysts for the Fischer-Tropsch preparatlon of hydrocarbons wlth Increased Cs+ selectivity
Geerlings, J. J. C. et al. PCT Int. Appl. WO 98 25,870 (Cl. CO7C1/04), 18 Jun 1998, EP Appl. 96/203,538, 13 Dee 1996; 21 pp. Using the Fischer-Tropsch catalytic reaction of carbon monoxide and hydrogen in which the synthesis gas feed is contacted at elevated temperature and pressure with a supported catalyst, comprising cobalt and manganese, Cs, hydrocarbons were prepared in high yield and selectivity. It was discovered that for low cobalt/manganese molar ratios, relatively high synthesis gas GHSV values resulted in high catalyst activities and high Cs+ hydrocarbon selectivities. QQlW361
Process for the preparation of an Improved supported catalyst, containing nlckei and cobalt, with or without noble metals, useful for the oxldatlve conversion of methane, natural gas and blogas to syngas
Choudhary, V. R. et al. US Appl., 1994, 359,35, 14 pp. A supported catalyst is prepared by depositing oxides of nickel and cobalt on a sintered low surface area porous inert support, the surface of which is precoated with an oxide of berylium, magnesium, calcium or a mixture thereof so that a protective layer of the alkaline earth oxide is formed between the oxides of nickel and cobalt, with or without noble metal, and the support and hence direct chemical interactions between the oxides of the group VIII transition metals and the reactive components of support, which leads to the formation of catalytically inactive binary oxide phases are avoided. QQlW362
Repowerlng with an Integrated GaslflcatlonCascaded Humldlfled Advanced Turbine (IG-MAT) cycle
Freier, M. D. et al. Proc. Am. Power Conf., 1998, 60, (2) 602-607. As examples of repowering of a typical US-based coal-fired power plant several cases of an oxygen-blown fixed-bed coal gasifier, based on British Gas-Lurgi technology, combined with a Cascaded Humidifed Advanced Turbine (IC-CHAT) power cycles were evaluated. Four gasifier cases were evaluated: (1) three circulating pressurized fluidized-bed combustor cases, (2) a bubbling pressurized fluidized-bed case, (3) an atmospheric circulating fluidized-bed case, and (4) a refuelling case using a process-derived fuel and a natural gas-fired combustion turbine-combined cycle case. When the cost of natural gas increases to >$2.25 to $2.50 per 10” Btu the IC-CHAT technology, along with the most competitive of the other advanced coal-fired technologies, become competitive with natural gasfired combined-cycles. QQlW363 Research on agglomeratlon In a coal gaslfler wlth twin fluidlzed beds Xiong, Y. et al. Proc. Annu. Int. Pittsburgh Coal Conf., 1997, 14, (20), 1622. Studied is the agglomeration of bed material in coal gasification with twin fluidized beds. In this paper, optical microscope, X-ray diffraction, and thermal analyses of agglomerates were carried out. The mechanism of bed defluidization and agglomeration were discussed.
Fuel and Energy Abstracts January 1999 35
New clean fuel from coal - direct dlmethyl ether QQlW354 synthesis from hydrogen and carbon monoxide Ogawa, T. et al. Proc. Annu. Int. Pittsburgh Coal Conf., 1997, 14, (30), 1526. For the direct production of Me20 by hydrogenation of CO at 533-553 K and 3-5 MPa using newly developed catalysts a process is presented.
Numerical and experimental 99/06355 jetting fluldized bed coal gaslfler
lnvestlgatlon
on a
Bi, J. et al. Proc. Annu. Int. Pittsburgh Coal Conf., 1997, 14, (20), 1-5. For a jetting fluidized bed coal gasifier with a conical distributor a numerical simulation study was conducted. This study was based on a steady-state model which took account of hydrodynamics, mass transfer, heat transfer and reactions in the grid zone, bubble zone and freeboard zone of the gasifier. Temperatures of the particle and gas in the jet, compositions in the bed, and some hydrodynamic characteristics were calculated. Effects of some operating conditions such as oxygen, steam flow rates, bed pressure and bed temperature on the temperatures in jet and gas compositions in the gasifier were numerically investigated. Temperature profiles of the particles and gas in the jet, and gas compositions in the bed were compared between the simulation and experiments carried out in a laboratory scale gasifier.
Partial oxidation of methane to syngas over Nil MgO, NllCaO and NI/Ce02
Gaseous fuels (derived gaseous fuels)
composition was CH4 3.6 wt%, C&d hydrocarbons 1.4 wt%, Hz 0.8 wt% and CO + CO2 96 wt%; the heating value of this gas was only 204 BTU/ SCF. These results show that char obtained during catalytic upgrading is extremely reactive and produces high yields of Hz and hydrocarbons. On the other hand, vacuum char is not so reactive and produces high yields of CO and COz. These results suggest that catalytic char is capable of producing a high BTU gas by simple steam gasification alone. QQlW359
A pressurized reactor with Integrated load cell for measuring the activities of Fischer-Tropschtatalysts and their loadings with llquld reactlon products (wax)
Raak, H. and Hedden, K. Erdoel, Erdgas, Kohle, 1998, 114, (5), 251-256. (In German) The Fischer-Tropsch synthesis is the heterogeneously catalysed hydrogenation of carbon monoxide with the objective of producing long-chain hydrocarbons. Particularly in countries with large natural gas reserves in geographically unfavourable fringe locations, it provides an alternative to the liquefaction of natural gas. The concept for a low-cost process for the conversion of natural gas to liquid hydrocarbons was elaborated in a joint project of the universities of Karlsruhe and Qatar. The following article surveys some results of a doctoral dissertation, which within the framework of this joint project deals with kinetic investigations in the start-up phase of the Fischer-Tropsch synthesis. The tests were carried out with a technologically precipitated iron catalyst of the Lurgi/Ruhrchemie joint venture at temperatures between 200 and 250” and with a reaction pressure of 20 bar. Under reaction conditions it was possible to show that the pore system of the catalyst is completely filled with higher hydrocarbons (wax) during the first hours of the synthesis. After this period the wax content of the catalyst is approximately 32 wt%. The interrelation between the activity of the catalyst and its load with liquid reaction products was examined with the aid of a pressurized reactor with an integrated load cell. This paper describes the measuring method and some experimental results, in particular the mass transfer limitations that occurred in the catalyst pores.
QQlQCl356
Tang, S. et al. Catal. Lett., 1998, 51, (3,4), 169-175. Over Ni/MgO, Ni/CaO and Ni/CeOz catalysts with nickel loading of 13 wt% partial oxidation of methane to syngas at atmospheric pressure and 750°C was examined. All catalysts had similar high conversion of methane and high selectivity to syngas, which nearly approached the values predicted by thermodynamic equilibrium. However, only Ni/MgO showed high resistance to carbon deposition under thermodynamically severe conditions. Its catalytic activity remained stable during 100 h of reaction, with no detectable carbon deposition. With an in-situ TPO-MS study, the oxidation of carbon deposited from pure CH., decomposition and from pure CO disproportionation was investigated: it showed that both were effectively inhibited over Ni/MgO. In addition, the catalysts were characterized by TPR, XRD and XPS. The excellent performance of Ni/MgO resulted from the formation of an ideal solid solution between NiO and MgO.
hydrocarbon Petroleum anaerobic laboratory aquifer columns
QQiQQ357
mineralization
in
Hunkeler, D. et al. J. Contam. Hydrol., 1998, 32, (l-2), 41-61. As a naturally occurring remediation process, anaerobic biodegradation of hydrocarbons at mineral oil-polluted sites has gathered increasing interest. Hydrocarbon biodegradation in laboratory aquifer columns in the absence of Oz and NOs was studied to calculate a mass balance of the anaerobic biodegradation processes. Laboratory columns containing aquifer material from a diesel fuel-polluted aquifer were operated at 25” for 65 days with artificial groundwater containing only S04’- and CO* as externally supplied oxidants. After 31 days of column operation, stable concentration profiles were observed for most of the measured dissolved species. In the column, nalkanes were selectively removed while branched alkanes persisted, suggesting a biological degradation. Furthermore, based on changes in concentrations of aromatic compounds with similar physicochemical properties in the effluent, it was concluded that toluene, p-xylene, and naphthalene were degraded. A carbon mass balance showed that 65% of hydrocarbons removed from the column were recovered as DIC; 20% were recovered as CH+ and 15% were eluted from the column. Calculations indicated that hydrocarbon mineralization coupled to S04’- reduction and methanogenesis contributed in equal proportions to hydrocarbon removal. Hydrocarbon mineralization coupled to Fe3+ and Mn4+ reduction was of minor importance.
Potential of producing high BTU gas from various QQiO6356 biomass-derived chars
Idem, R. 0. et al. Making Bus. Biomass Energy, Environ., Chemical, Fibers Mater., Proc. Biomass Conf. Am. 3rd, 1997, (1) 383-390. Edited by Overend, R. P. and Chornet, E. In an Inconel-alloy microreactor at a steam rate of 10 g/h using chars obtained from two processes steam gasification of char was conducted at temperatures of 600, 700 and 800”. The first process was the char obtained from bio-oil upgrading using HZSM-5 catalyst (i.e. catalytic char) and the second was the char obtained from vacuum distillation of bio-oil (i.e. vacuum char). At 800”, conversion of catalytic char was very high (close to 84 wt%) and produced a gas which had a heating value of 931 BTU/SCF (methane has a heating value of 1000 BTU/SCF). On the other hand, conversion of the vacuum char at 800” was 60 wt%. The product
QQlQO369
Process and catalysts for the Fischer-Tropsch preparatlon of hydrocarbons wlth Increased Cs+ selectivity
Geerlings, J. J. C. et al. PCT Int. Appl. WO 98 25,870 (Cl. CO7C1/04), 18 Jun 1998, EP Appl. 96/203,538, 13 Dee 1996; 21 pp. Using the Fischer-Tropsch catalytic reaction of carbon monoxide and hydrogen in which the synthesis gas feed is contacted at elevated temperature and pressure with a supported catalyst, comprising cobalt and manganese, Cs, hydrocarbons were prepared in high yield and selectivity. It was discovered that for low cobalt/manganese molar ratios, relatively high synthesis gas GHSV values resulted in high catalyst activities and high Cs+ hydrocarbon selectivities. QQlW361
Process for the preparation of an Improved supported catalyst, containing nlckei and cobalt, with or without noble metals, useful for the oxldatlve conversion of methane, natural gas and blogas to syngas
Choudhary, V. R. et al. US Appl., 1994, 359,35, 14 pp. A supported catalyst is prepared by depositing oxides of nickel and cobalt on a sintered low surface area porous inert support, the surface of which is precoated with an oxide of berylium, magnesium, calcium or a mixture thereof so that a protective layer of the alkaline earth oxide is formed between the oxides of nickel and cobalt, with or without noble metal, and the support and hence direct chemical interactions between the oxides of the group VIII transition metals and the reactive components of support, which leads to the formation of catalytically inactive binary oxide phases are avoided. QQlW362
Repowerlng with an Integrated GaslflcatlonCascaded Humldlfled Advanced Turbine (IG-MAT) cycle
Freier, M. D. et al. Proc. Am. Power Conf., 1998, 60, (2) 602-607. As examples of repowering of a typical US-based coal-fired power plant several cases of an oxygen-blown fixed-bed coal gasifier, based on British Gas-Lurgi technology, combined with a Cascaded Humidifed Advanced Turbine (IC-CHAT) power cycles were evaluated. Four gasifier cases were evaluated: (1) three circulating pressurized fluidized-bed combustor cases, (2) a bubbling pressurized fluidized-bed case, (3) an atmospheric circulating fluidized-bed case, and (4) a refuelling case using a process-derived fuel and a natural gas-fired combustion turbine-combined cycle case. When the cost of natural gas increases to >$2.25 to $2.50 per 10” Btu the IC-CHAT technology, along with the most competitive of the other advanced coal-fired technologies, become competitive with natural gasfired combined-cycles. QQlW363 Research on agglomeratlon In a coal gaslfler wlth twin fluidlzed beds Xiong, Y. et al. Proc. Annu. Int. Pittsburgh Coal Conf., 1997, 14, (20), 1622. Studied is the agglomeration of bed material in coal gasification with twin fluidized beds. In this paper, optical microscope, X-ray diffraction, and thermal analyses of agglomerates were carried out. The mechanism of bed defluidization and agglomeration were discussed.
Fuel and Energy Abstracts January 1999 35