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01712 Trace element evaporation during coal gasification based on a thermodynamic equilibrium calculation approach
04 By-products related to fuels 03/01709 Steam reforming iridium catalysts
of dodecane
over supported
Ando, T. et al. Journal of the Japan Petroleum Institute, 2002, 45, (6), 409413. In order to discuss the possibility of steam reforming of kerosene to produce hydrogen for the on-site fuel cell co-generation system, steam reforming of dodecane, as a model compound of kerosene, was carried out in the presence or absence of oxygen at 773-1073 K using a fixed bed flow reactor. The catalytic performance of Ru, Rh, and Ir-loaded catalysts was compared. In the steam reforming of dodecane, Rh/LazOs and Ru/LazOs afforded higher dodecane conversions and hydrogen yields than those with Ir/LazOs. Dodecane conversion, however, increased with the addition of a small amount of oxygen together with steam over Ir/LazOs catalyst, and the conversion of dodecane reached those obtained over Rh and Ru/LazOs catalysts. Basic support LazO, exhibited the best performance for the steam reforming in the presence of oxygen using Ir catalyst among the supports tested.
03101710 transport
Syn as production mem !I rane
method
utilizing
an oxygen
Prasad, R. et al. U.S. Pat. Appl. Publ. US 2002 155,061 (Cl. 423-652; COlB3/26), 24 Ott 2002, Appl. 840,101. A crude syngas product stream is produced containing Hz and CO by conversion of a methane or natural gas feed stream by CO2 and steam reforming. The crude syngas product stream contains COz and moisture which are removed. An initial stage has an oxygen transport membrane reactor separating oxygen from an OS-containing gas and having a catalyst at the anode side to promote carbon dioxide or steam methane reforming. Methane is partially oxidized prior to the reforming within an extrant section of the oxygen transport membrane not containing the reforming catalyst. Since, the conversion is shared between two stages, the oxygen transport membrane reactor can be operated at a sufficiently low temperature to avoid ceramic membrane deterioration due to creep effect. The subsequent stage can be operated at a higher temperature with more favourable equilibrium conditions to complete the conversion of the methane. The unit contains a hydrocarbon desulfurization unit to prevent catalyst poisoning.
03/01711 The solar thermal gasification conversion efficiency and COP mitigation
of coal - energy potential
Zedtwitz, P. V. and Steinfeld, A. Energy, 2003, 28, (5), 441456. The steam-gasification of coal (peat, lignite, bituminous, and anthracite) into syngas is investigated using concentrated solar energy as the source of high-temperature process heat. The advantages of the solardriven process are threefold: (1) the discharge of pollutants is avoided; (2) the gaseous products are not contaminated by combustion byproducts; and (3) the calorific value of the fuel is upgraded. A second-law analysis is carried out for a blackbody solar cavity-receiver/ reactor operated at 1350 K and subjected to a mean solar flux concentration ratio of 2000. Two technically viable routes for generating electricity using the gasification products are examined: (1) syngas is used to fuel a 55%-efficient combined Brayton-Rankine cycle; and (2) syngas is further processed to Hz (by water-gas shift reaction followed by Hz/CO* separation) which is used to fuel a 65%efficient fuel cell. The maximum exergy efficiency, defined as the ratio of electric power output to the thermal power input (solar power + heating value of reactants), reaches 50% for the combined cycle route and 46% for the fuel cell route. Both of these routes offer a net gain in the electrical output by a factor varying in the range 1.7-1.9, depending on the coal type and the power generation route, vis-a-vis the direct use of coal for fueling a 35%-efficient Rankine cycle. Specific CO2 emissions amounts to 0.49-0.56 kg COz/kWh,, about half as much as the specific emissions discharged by conventional coal-fired power plants. Solar/coal hybrid processes, such as the one examined in this paper, offer important intermediate solutions towards a sustainable energy supply system.
03/01712 Trace element evaporation during coal gasification based on a thermodynamic equilibrium calculation approach Diaz-Somoano, M. and Martinez-Tarazona, M. R. Fuel, 2003, 82, (2). 137-145. Thermodynamic equilibrium calculations using the HSC-Chemistry program were performed to determine the distribution and mode of occurrence of potentially toxic and corrosive trace elements in gases from coal gasification processes. The influence of temperature, pressure and gas atmospheres on equilibrium composition was evaluated. In these reducing conditions, the behaviour of the trace elements is complex, but some form of organization can be attempted. Elements were classified into three groups. Group A includes those elements that, according to thermodynamic data at equilibrium, could probably be condensed in coal gasification. Mn is classified in this group. Group B contains those elements that could be totally or partially in gas phase in gas cleaning conditions, and can be divided
into two subgroups, depending on whether the hot or cold. Co, Be, Sb, As, Cd, Pb, Zn, Ni, V, group. Group C contains those elements that phase in all the possible conditions, including Hg and B are the elements that make up this
03/01713 oxidation
YSZ-SrC0,,.,Fe,,.803-s of methane to syngas
cleaning conditions Cr are elements in could be totally in flue gas emissions. group.
membranes
are this gas Se,
for the partial
Gu, X.-H. et al. AIChE Journal, 2002, 48, (9), 2051-2060. The perovskite-related yttria-stabilized zirconia promoted SrC00,4Fe0.60s-6 (SCFZ) oxides were used to construct membrane reactors for the partial oxidation of methane to syngas (POM). The oxygen permeability study of the SCFZ membrane in the air/helium gradient showed that the apparent activation energy was ~69 * 5kJ/ mol at 1023-1223 K, and the oxygen flux was controlled by the bulk diffusion and surface exchange rate. In a cofeed reactor packed with SCFZ pellets and a blank SCFZ membrane reactor without any catalyst packing, the SCFZ oxides showed low catalytic activity for POM in the fixed-bed reactor and no POM catalytic activity in the membrane reactor. An SCFZ membrane reactor with NiOiAlzOs catalyst was continuously running for over 220 h under constant operational conditions. While =64% of methane was converted with 100% CO selectivity after reaching the steady state, the oxygen flux was x10 times the value of the air/helium gradient, in the reactor packed with the catalyst. The oxygen flux of SCFZ membranes in the reducing atmosphere could be limited by the surface reaction rate at the reaction side.
04 BY-PRODUCTS RELATED TO FUELS 03lO1714 Adsorption of SO* using vanadium and vanadium-copper supported on activated carbon Carabineiro, S. A. C. et al. Catalysis Today, 2003, 78, (l-4) 203-210. Activated carbon impregnated with precursor salts of Ba, Co, Cu, Fe, Mg, Mn, Ni, Pb and V and their binary mixtures was used for adsorption of SOz at 20°C. The most promising materials for SO1 removal are carbons doped with V, Cu and mainly their binary mixtures, which show a synergetic effect. Kinetic curves and isotherms of SO1 adsorption were obtained at 20°C. These isotherms are reasonably well fitted by the Langmuir model and the respective parameters were determined. TPD experiments show that adsorption of SOz increases the oxygenated groups on the carbon surface. The sample doped with V, after SO:, adsorption at 2o”C, presents an increase of basic oxygenated groups, which may be responsible for the observed extra adsorption of SOz.
03/01715 Estimation efficiency for organic compounds
of activated carbon adsorption vapours I. A strategy for selecting
test
Fangmark, I. E. et al. Carbon, 2002, 40, (15), 2861-2869. Strategies for developing quantitative structure-affinity relationships (QSAW) for the prediction of break-through performance of 31 chlorinated hydrocarbons on activated carbon have been studied. Two different approaches for the selection of a limited set of compounds for modelling were evaluated through the predictive power of the resulting QSAfR models. When the model was based on a training-set selected without a rational strategy, the developed QSAfR model showed poor predictive performance. Accordingly, such models have a limited capability to produce information concerning the important adsorbate related parameters influencing adsorption. By using a strategy where multivariate data analytical techniques are used in conjunction with statistical experimental design to select a balanced set of compounds for break-through performance evaluation, it was possible to develop QSAfR models with high predictive capability.
03101716 Flue gas treatment from oil-fired fly ash
by activated
carbon
obtained
Davini, P. Carbon, 2002, 40, (1 l), 197331979. The treatment of the solid particulates derived from the combustion of heavy oils (that is, oil-fired fly ash) with acidic solutions (HCI and HF) followed by activation at 900°C with CO1 and then with O2 (1%) in Nz at 8Oo”C, produces activated carbon having high surface area values (measured both by Nz adsorption at 77 K and by COz adsorption at 273 K) and surface basic characteristics. This carbon appears to be suitable for SOz and NO, adsorption and hence for industrial flue gas treatment processes. By submitting the activated carbon thus obtained to some adsorption/desorption cycles of gaseous mixtures having a similar composition to that of flue gases, its general characteristics (surface
Fuel and Energy Abstracts
September
2003
297
of dodecane
over supported
Ando, T. et al. Journal of the Japan Petroleum Institute, 2002, 45, (6), 409413. In order to discuss the possibility of steam reforming of kerosene to produce hydrogen for the on-site fuel cell co-generation system, steam reforming of dodecane, as a model compound of kerosene, was carried out in the presence or absence of oxygen at 773-1073 K using a fixed bed flow reactor. The catalytic performance of Ru, Rh, and Ir-loaded catalysts was compared. In the steam reforming of dodecane, Rh/LazOs and Ru/LazOs afforded higher dodecane conversions and hydrogen yields than those with Ir/LazOs. Dodecane conversion, however, increased with the addition of a small amount of oxygen together with steam over Ir/LazOs catalyst, and the conversion of dodecane reached those obtained over Rh and Ru/LazOs catalysts. Basic support LazO, exhibited the best performance for the steam reforming in the presence of oxygen using Ir catalyst among the supports tested.
03101710 transport
Syn as production mem !I rane
method
utilizing
an oxygen
Prasad, R. et al. U.S. Pat. Appl. Publ. US 2002 155,061 (Cl. 423-652; COlB3/26), 24 Ott 2002, Appl. 840,101. A crude syngas product stream is produced containing Hz and CO by conversion of a methane or natural gas feed stream by CO2 and steam reforming. The crude syngas product stream contains COz and moisture which are removed. An initial stage has an oxygen transport membrane reactor separating oxygen from an OS-containing gas and having a catalyst at the anode side to promote carbon dioxide or steam methane reforming. Methane is partially oxidized prior to the reforming within an extrant section of the oxygen transport membrane not containing the reforming catalyst. Since, the conversion is shared between two stages, the oxygen transport membrane reactor can be operated at a sufficiently low temperature to avoid ceramic membrane deterioration due to creep effect. The subsequent stage can be operated at a higher temperature with more favourable equilibrium conditions to complete the conversion of the methane. The unit contains a hydrocarbon desulfurization unit to prevent catalyst poisoning.
03/01711 The solar thermal gasification conversion efficiency and COP mitigation
of coal - energy potential
Zedtwitz, P. V. and Steinfeld, A. Energy, 2003, 28, (5), 441456. The steam-gasification of coal (peat, lignite, bituminous, and anthracite) into syngas is investigated using concentrated solar energy as the source of high-temperature process heat. The advantages of the solardriven process are threefold: (1) the discharge of pollutants is avoided; (2) the gaseous products are not contaminated by combustion byproducts; and (3) the calorific value of the fuel is upgraded. A second-law analysis is carried out for a blackbody solar cavity-receiver/ reactor operated at 1350 K and subjected to a mean solar flux concentration ratio of 2000. Two technically viable routes for generating electricity using the gasification products are examined: (1) syngas is used to fuel a 55%-efficient combined Brayton-Rankine cycle; and (2) syngas is further processed to Hz (by water-gas shift reaction followed by Hz/CO* separation) which is used to fuel a 65%efficient fuel cell. The maximum exergy efficiency, defined as the ratio of electric power output to the thermal power input (solar power + heating value of reactants), reaches 50% for the combined cycle route and 46% for the fuel cell route. Both of these routes offer a net gain in the electrical output by a factor varying in the range 1.7-1.9, depending on the coal type and the power generation route, vis-a-vis the direct use of coal for fueling a 35%-efficient Rankine cycle. Specific CO2 emissions amounts to 0.49-0.56 kg COz/kWh,, about half as much as the specific emissions discharged by conventional coal-fired power plants. Solar/coal hybrid processes, such as the one examined in this paper, offer important intermediate solutions towards a sustainable energy supply system.
03/01712 Trace element evaporation during coal gasification based on a thermodynamic equilibrium calculation approach Diaz-Somoano, M. and Martinez-Tarazona, M. R. Fuel, 2003, 82, (2). 137-145. Thermodynamic equilibrium calculations using the HSC-Chemistry program were performed to determine the distribution and mode of occurrence of potentially toxic and corrosive trace elements in gases from coal gasification processes. The influence of temperature, pressure and gas atmospheres on equilibrium composition was evaluated. In these reducing conditions, the behaviour of the trace elements is complex, but some form of organization can be attempted. Elements were classified into three groups. Group A includes those elements that, according to thermodynamic data at equilibrium, could probably be condensed in coal gasification. Mn is classified in this group. Group B contains those elements that could be totally or partially in gas phase in gas cleaning conditions, and can be divided
into two subgroups, depending on whether the hot or cold. Co, Be, Sb, As, Cd, Pb, Zn, Ni, V, group. Group C contains those elements that phase in all the possible conditions, including Hg and B are the elements that make up this
03/01713 oxidation
YSZ-SrC0,,.,Fe,,.803-s of methane to syngas
cleaning conditions Cr are elements in could be totally in flue gas emissions. group.
membranes
are this gas Se,
for the partial
Gu, X.-H. et al. AIChE Journal, 2002, 48, (9), 2051-2060. The perovskite-related yttria-stabilized zirconia promoted SrC00,4Fe0.60s-6 (SCFZ) oxides were used to construct membrane reactors for the partial oxidation of methane to syngas (POM). The oxygen permeability study of the SCFZ membrane in the air/helium gradient showed that the apparent activation energy was ~69 * 5kJ/ mol at 1023-1223 K, and the oxygen flux was controlled by the bulk diffusion and surface exchange rate. In a cofeed reactor packed with SCFZ pellets and a blank SCFZ membrane reactor without any catalyst packing, the SCFZ oxides showed low catalytic activity for POM in the fixed-bed reactor and no POM catalytic activity in the membrane reactor. An SCFZ membrane reactor with NiOiAlzOs catalyst was continuously running for over 220 h under constant operational conditions. While =64% of methane was converted with 100% CO selectivity after reaching the steady state, the oxygen flux was x10 times the value of the air/helium gradient, in the reactor packed with the catalyst. The oxygen flux of SCFZ membranes in the reducing atmosphere could be limited by the surface reaction rate at the reaction side.
04 BY-PRODUCTS RELATED TO FUELS 03lO1714 Adsorption of SO* using vanadium and vanadium-copper supported on activated carbon Carabineiro, S. A. C. et al. Catalysis Today, 2003, 78, (l-4) 203-210. Activated carbon impregnated with precursor salts of Ba, Co, Cu, Fe, Mg, Mn, Ni, Pb and V and their binary mixtures was used for adsorption of SOz at 20°C. The most promising materials for SO1 removal are carbons doped with V, Cu and mainly their binary mixtures, which show a synergetic effect. Kinetic curves and isotherms of SO1 adsorption were obtained at 20°C. These isotherms are reasonably well fitted by the Langmuir model and the respective parameters were determined. TPD experiments show that adsorption of SOz increases the oxygenated groups on the carbon surface. The sample doped with V, after SO:, adsorption at 2o”C, presents an increase of basic oxygenated groups, which may be responsible for the observed extra adsorption of SOz.
03/01715 Estimation efficiency for organic compounds
of activated carbon adsorption vapours I. A strategy for selecting
test
Fangmark, I. E. et al. Carbon, 2002, 40, (15), 2861-2869. Strategies for developing quantitative structure-affinity relationships (QSAW) for the prediction of break-through performance of 31 chlorinated hydrocarbons on activated carbon have been studied. Two different approaches for the selection of a limited set of compounds for modelling were evaluated through the predictive power of the resulting QSAfR models. When the model was based on a training-set selected without a rational strategy, the developed QSAfR model showed poor predictive performance. Accordingly, such models have a limited capability to produce information concerning the important adsorbate related parameters influencing adsorption. By using a strategy where multivariate data analytical techniques are used in conjunction with statistical experimental design to select a balanced set of compounds for break-through performance evaluation, it was possible to develop QSAfR models with high predictive capability.
03101716 Flue gas treatment from oil-fired fly ash
by activated
carbon
obtained
Davini, P. Carbon, 2002, 40, (1 l), 197331979. The treatment of the solid particulates derived from the combustion of heavy oils (that is, oil-fired fly ash) with acidic solutions (HCI and HF) followed by activation at 900°C with CO1 and then with O2 (1%) in Nz at 8Oo”C, produces activated carbon having high surface area values (measured both by Nz adsorption at 77 K and by COz adsorption at 273 K) and surface basic characteristics. This carbon appears to be suitable for SOz and NO, adsorption and hence for industrial flue gas treatment processes. By submitting the activated carbon thus obtained to some adsorption/desorption cycles of gaseous mixtures having a similar composition to that of flue gases, its general characteristics (surface
Fuel and Energy Abstracts
September
2003
297