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02473 Carbon dioxide reforming of methane over coprecipitated Ni-CeO2, Ni-ZrO2 and Ni-Ce-ZrO2 catalysts
03 Gaseous fuels (derived gaseous fuels) increase in electricity output, decrease of 45 million won (exchange rate: US$1 = 1200 won) in costs, and increase of 10.3 thousand ton of CO2 in global warming potentials due to same period (5 year) of technological improvement. In the maximum utilization potential scenario, LFG electricity generation technology is substituted for coal steam, nuclear, and combined cycle process. Annual cost per electricity product of LFG electricity facilities (GE 58MW, GT 53.5MW, and ST 54.5MW) are 45.1, 34.3, and 24.4 won/kWh, and steam turbine process is cost-saving. LFG-utilization with other forms of energy utilization reduces global warming potential by maximum 75% with compared to spontaneous emission of CH4. LFG electricity generation would be the good solution for CO2 displacement over the medium term and additional energy profits.
05•02467 Environmental implications of converting light gas vehicles: the Brazilian experience Dondero, L. and Goldemberg, J. Energy Policy, 2005, 33, (13), 1703i708. This paper outlines the Brazilian experience with gas vehicles, identifies the current environmental problem faced by the aftermarket conversions and proposes alternatives that would help revert the present scenario, in order to profit, not only from the economic advantages the use of gas entails, but also the environmental ones. The Brazilian case shows the great importance of improving technological transfer know-how to developing countries.
05/02468 Exergy analysis of liquefied natural gas cold energy recovering cycles Qiang, Q. et al. International Journal of Energy Research, 2005, 29, (1), 65-78. Liquefied natural gas (LNG) is known as green fuel used in power plant, automobile and so forth due to its higher energy density and environmentally friendly advantages. LNG, besides its high quality chemical exergy, has plenty of physical exergy such as cold exergy and pressure exergy, which could be utilized further. Analysis of physical exergy and its affected factors has been conducted. Based on the analysis, several cycles used for recovering and applying the physical exergy of LNG, such as combined power cycle, gas turbine power generation cycle and automobile air-conditioning system have been proposed. The parameters affecting the performance of the cycles are discussed. The recovery and utilization of physical exergy of LNG are the important measures to save energy and protect the environment.
05•02469 The role of hydrogen for the long term development of sustainable energy systems - a case study for Germany Fischedick, M. et al. Solar Energy, 2005, 78, (5), 678-686. Based on different current long-term energy scenarios the paper discusses the future perspectives of hydrogen in the German energy system as a representative example for the development of sustainable energy systems. The scenario analysis offers varying outlines of the future energy system that determine the possible role of hydrogen. The paper discusses the possibilities of expanding the share of renewable energy and the resulting prospects for establishing clean hydrogen production from renewable energy sources. Emphasis is given to the questions of an ecologically efficient allocation of limited renewable energy resources that can only be assessed from a systems analysis perspective. Findings from recent studies for Germany reveal a strong competition between the direct input into the electricity system and an indirect use as fuel in the transport sector. Moreover, the analysis underlines the paramount importance of reducing energy demand as the inevitable prerequisite for any renewable energy system.
Derived gaseous fuels 05•02470 A new process for synthesis gas by co-gasifying coal and natural gas Song, X. and Guo, Z. Fuel, 2005, 84, (5), 525-531. Production of synthesis gas with coal and natural gas co-gasification is a new process based on coupling of methane steam-reforming and coal gasification. The process concept is discussed in this paper. Experiments are carried out in a laboratory fixed-bed gasifying reactor to investigate the effect of feedstock on composition, ratio of hydrogen to carbon monoxide, concentrations of hydrogen and carbon monoxide in the produced raw synthesis gas. Preliminary experimental results indicate that the effect of steam flow rate on component, ratio of hydrogen to carbon monoxide and concentrations of hydrogen and carbon monoxide of the raw synthesis gas is slight, while the effect of oxygen flow rate is pronounced. When the ratio of oxygen to methane in feedstock is below 1, the ratio of hydrogen to carbon monoxide is greater than 1 and the total concentration of hydrogen and carbon
364 Fuel and Energy Abstracts November 2005
monoxide is above 90%. Comparison of experimental results with calculated results shows that the composition of raw synthesis gas is near equilibrium.
05•02471 AI-Cu-Fe quasicrystals for steam reforming of methanol: a new form of copper catalysts Kameoka, S. et al. Catalysis Today, 2004, 93-95, 23-26. Alloy catalysts were prepared by leaching various structures of A1-Cu(Fe) alloys (quasicrystal (QC), beta- or tbeta-phase) in NaOH and NazCO3 aqueous solutions. Comparison of the catalytic properties for steam reforming of methanol (SRM) on different AI-Cu-(Fe) alloy phases (quasicrystalline versus crystalline phase) was made. At high temperatures (e.g. 360°C), the catalytic activity of the QC catalyst (5% Na2CO3-1eached) for the SRM was much higher than that of other phase catalysts. No sintering of highly dispersed copper particles on QC catalyst was observed by XRD measurements even after the SRM reaction at 360°C. The authors propose that the high catalytic activity and the excellent thermal stability of copper particles on QC catalyst are due to the immiscibility of Fe with Cu and the interaction with QC surface.
05/02472 Analysis of sulfur-iodine thermochemical cycle for solar hydrogen production. Part h decomposition of sulfuric acid Huang, C. and T-Raissi, A. Solar Energy, 2005, 78, (5), 632-646. The sulfur-iodine (S-I) thermochemical water splitting cycle is one of the most studied cycles for hydrogen (H2) production. S-I cycle consists of four sections: (I) acid production and separation and oxygen purification, (II) sulfuric acid concentration and decomposition, (III) hydrniodic acid (HI) concentration, and (IV) HI decomposition and Hz purification. Section II of the cycle is an endothermic reaction driven by the heat input from a high temperature source. Analysis of the S-I cycle in the past 30 years have been focused mostly on the utilization of nuclear power as the high temperature heat source for the sulfuric acid decomposition step. Thermodynamic as well as kinetic considerations indicate that both the extent and rate of sulfuric acid decomposition can be improved at very high temperatures (in excess of 1000°C) available only from solar concentrators. The beneficial effect of high temperature solar heat for decomposition of sulfuric acid in the S-I cycle is described in this paper. The authors used Aspen Technologies' HYSYS chemical process simulator (CPS) to develop flowsheets for sulfuric acid (H2SO4) decomposition that include all mass and heat balances. Based on the HYSYS analyses, two new process flowsheets were developed. These new sulfuric acid decomposition processes are simpler and more stable than previous processes and yield higher conversion efficiencies for the sulfuric acid decomposition and sulfur dioxide and oxygen formation.
05/02473 Carbon dioxide reforming of methane over coprecipitated Ni-CeO2, Ni-ZrO2 and Ni-Ce-ZrO2 catalysts Roh, H.-S. et al. Catalysis Today, 2004, 93-95, 39-44. A co-precipitation method was employed to prepare nickel oxide dispersed on CeOe, ZrO2 and cubic Ce0.sZr0.zO2 support to obtain catalysts useful for carbon dioxide reforming of methane reaction. The Ni-CeOz and Ni-Ce-ZrO2 catalysts showed relatively high activity and stability, while the Ni-ZrO2 catalyst deactivated in the initial stage of the reaction due to serious carbon formation. The co-precipitated NiCe-ZrO2 catalyst exhibited the highest catalytic activity (CH4 conversion >97% at 800°C) among the catalysts tested and the activity was maintained without significant loss during the reaction for 100 h. The enhanced catalytic activity and stability of the co-precipitated Ni-CeZrOz catalyst is attributed to the combination of nano-crystalline nature of cubic Ce0.sZro.202 support and finely dispersed nano-sized NiO,-2 crystallites resulting in intimate contact between Ni and support, better Ni dispersion, higher Ni surface area and enhanced oxygen transfer during the reaction.
05/02474 Highly active and coking resistant Ni/CeO2-ZrO2 catalyst for partial oxidation of methane Xu, S. and Wang, X. Fuel, 2005, 84, (5), 563-567. Nickel catalysts over the CeO2-ZrO2 solid solution were successfully prepared by the co-precipitation method for partial oxidation of methane. The structures of the catalysts were systematically examined by N2 adsorption/desorption, CO chemisorption, X-ray diffraction (XRD) and H2-TPR techniques. The catalytic performance and carbon deposition were investigated for partial oxidation of methane as well. The results showed that the Ni/CeO2-ZrOz catalysts had a large BET area and fine Ni dispersion. By the co-precipitation method, Ni and CeO2-ZrO2 solid solution had strong interaction confirmed by the H2TPR analysis. The Ni/CeOz-ZrOz catalysts showed high activity and stability and the Ni/Ce0.25Zr0.7502 exhibited the best activity and coking resistance among these catalysts. The catalytic activities and coking resistant behaviours of catalysts were affected by the surface and structural properties of the catalysts.
05•02467 Environmental implications of converting light gas vehicles: the Brazilian experience Dondero, L. and Goldemberg, J. Energy Policy, 2005, 33, (13), 1703i708. This paper outlines the Brazilian experience with gas vehicles, identifies the current environmental problem faced by the aftermarket conversions and proposes alternatives that would help revert the present scenario, in order to profit, not only from the economic advantages the use of gas entails, but also the environmental ones. The Brazilian case shows the great importance of improving technological transfer know-how to developing countries.
05/02468 Exergy analysis of liquefied natural gas cold energy recovering cycles Qiang, Q. et al. International Journal of Energy Research, 2005, 29, (1), 65-78. Liquefied natural gas (LNG) is known as green fuel used in power plant, automobile and so forth due to its higher energy density and environmentally friendly advantages. LNG, besides its high quality chemical exergy, has plenty of physical exergy such as cold exergy and pressure exergy, which could be utilized further. Analysis of physical exergy and its affected factors has been conducted. Based on the analysis, several cycles used for recovering and applying the physical exergy of LNG, such as combined power cycle, gas turbine power generation cycle and automobile air-conditioning system have been proposed. The parameters affecting the performance of the cycles are discussed. The recovery and utilization of physical exergy of LNG are the important measures to save energy and protect the environment.
05•02469 The role of hydrogen for the long term development of sustainable energy systems - a case study for Germany Fischedick, M. et al. Solar Energy, 2005, 78, (5), 678-686. Based on different current long-term energy scenarios the paper discusses the future perspectives of hydrogen in the German energy system as a representative example for the development of sustainable energy systems. The scenario analysis offers varying outlines of the future energy system that determine the possible role of hydrogen. The paper discusses the possibilities of expanding the share of renewable energy and the resulting prospects for establishing clean hydrogen production from renewable energy sources. Emphasis is given to the questions of an ecologically efficient allocation of limited renewable energy resources that can only be assessed from a systems analysis perspective. Findings from recent studies for Germany reveal a strong competition between the direct input into the electricity system and an indirect use as fuel in the transport sector. Moreover, the analysis underlines the paramount importance of reducing energy demand as the inevitable prerequisite for any renewable energy system.
Derived gaseous fuels 05•02470 A new process for synthesis gas by co-gasifying coal and natural gas Song, X. and Guo, Z. Fuel, 2005, 84, (5), 525-531. Production of synthesis gas with coal and natural gas co-gasification is a new process based on coupling of methane steam-reforming and coal gasification. The process concept is discussed in this paper. Experiments are carried out in a laboratory fixed-bed gasifying reactor to investigate the effect of feedstock on composition, ratio of hydrogen to carbon monoxide, concentrations of hydrogen and carbon monoxide in the produced raw synthesis gas. Preliminary experimental results indicate that the effect of steam flow rate on component, ratio of hydrogen to carbon monoxide and concentrations of hydrogen and carbon monoxide of the raw synthesis gas is slight, while the effect of oxygen flow rate is pronounced. When the ratio of oxygen to methane in feedstock is below 1, the ratio of hydrogen to carbon monoxide is greater than 1 and the total concentration of hydrogen and carbon
364 Fuel and Energy Abstracts November 2005
monoxide is above 90%. Comparison of experimental results with calculated results shows that the composition of raw synthesis gas is near equilibrium.
05•02471 AI-Cu-Fe quasicrystals for steam reforming of methanol: a new form of copper catalysts Kameoka, S. et al. Catalysis Today, 2004, 93-95, 23-26. Alloy catalysts were prepared by leaching various structures of A1-Cu(Fe) alloys (quasicrystal (QC), beta- or tbeta-phase) in NaOH and NazCO3 aqueous solutions. Comparison of the catalytic properties for steam reforming of methanol (SRM) on different AI-Cu-(Fe) alloy phases (quasicrystalline versus crystalline phase) was made. At high temperatures (e.g. 360°C), the catalytic activity of the QC catalyst (5% Na2CO3-1eached) for the SRM was much higher than that of other phase catalysts. No sintering of highly dispersed copper particles on QC catalyst was observed by XRD measurements even after the SRM reaction at 360°C. The authors propose that the high catalytic activity and the excellent thermal stability of copper particles on QC catalyst are due to the immiscibility of Fe with Cu and the interaction with QC surface.
05/02472 Analysis of sulfur-iodine thermochemical cycle for solar hydrogen production. Part h decomposition of sulfuric acid Huang, C. and T-Raissi, A. Solar Energy, 2005, 78, (5), 632-646. The sulfur-iodine (S-I) thermochemical water splitting cycle is one of the most studied cycles for hydrogen (H2) production. S-I cycle consists of four sections: (I) acid production and separation and oxygen purification, (II) sulfuric acid concentration and decomposition, (III) hydrniodic acid (HI) concentration, and (IV) HI decomposition and Hz purification. Section II of the cycle is an endothermic reaction driven by the heat input from a high temperature source. Analysis of the S-I cycle in the past 30 years have been focused mostly on the utilization of nuclear power as the high temperature heat source for the sulfuric acid decomposition step. Thermodynamic as well as kinetic considerations indicate that both the extent and rate of sulfuric acid decomposition can be improved at very high temperatures (in excess of 1000°C) available only from solar concentrators. The beneficial effect of high temperature solar heat for decomposition of sulfuric acid in the S-I cycle is described in this paper. The authors used Aspen Technologies' HYSYS chemical process simulator (CPS) to develop flowsheets for sulfuric acid (H2SO4) decomposition that include all mass and heat balances. Based on the HYSYS analyses, two new process flowsheets were developed. These new sulfuric acid decomposition processes are simpler and more stable than previous processes and yield higher conversion efficiencies for the sulfuric acid decomposition and sulfur dioxide and oxygen formation.
05/02473 Carbon dioxide reforming of methane over coprecipitated Ni-CeO2, Ni-ZrO2 and Ni-Ce-ZrO2 catalysts Roh, H.-S. et al. Catalysis Today, 2004, 93-95, 39-44. A co-precipitation method was employed to prepare nickel oxide dispersed on CeOe, ZrO2 and cubic Ce0.sZr0.zO2 support to obtain catalysts useful for carbon dioxide reforming of methane reaction. The Ni-CeOz and Ni-Ce-ZrO2 catalysts showed relatively high activity and stability, while the Ni-ZrO2 catalyst deactivated in the initial stage of the reaction due to serious carbon formation. The co-precipitated NiCe-ZrO2 catalyst exhibited the highest catalytic activity (CH4 conversion >97% at 800°C) among the catalysts tested and the activity was maintained without significant loss during the reaction for 100 h. The enhanced catalytic activity and stability of the co-precipitated Ni-CeZrOz catalyst is attributed to the combination of nano-crystalline nature of cubic Ce0.sZro.202 support and finely dispersed nano-sized NiO,-2 crystallites resulting in intimate contact between Ni and support, better Ni dispersion, higher Ni surface area and enhanced oxygen transfer during the reaction.
05/02474 Highly active and coking resistant Ni/CeO2-ZrO2 catalyst for partial oxidation of methane Xu, S. and Wang, X. Fuel, 2005, 84, (5), 563-567. Nickel catalysts over the CeO2-ZrO2 solid solution were successfully prepared by the co-precipitation method for partial oxidation of methane. The structures of the catalysts were systematically examined by N2 adsorption/desorption, CO chemisorption, X-ray diffraction (XRD) and H2-TPR techniques. The catalytic performance and carbon deposition were investigated for partial oxidation of methane as well. The results showed that the Ni/CeO2-ZrOz catalysts had a large BET area and fine Ni dispersion. By the co-precipitation method, Ni and CeO2-ZrO2 solid solution had strong interaction confirmed by the H2TPR analysis. The Ni/CeOz-ZrOz catalysts showed high activity and stability and the Ni/Ce0.25Zr0.7502 exhibited the best activity and coking resistance among these catalysts. The catalytic activities and coking resistant behaviours of catalysts were affected by the surface and structural properties of the catalysts.