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03467 Biological processes for mitigation of greenhouse gases
07 Alternative
energy sources (bioconversion
energy)
Bipolar plate materials for the solid polymer fuel cell (SPFC), alternative to the presently used graphite, should fulfil the following requirements in order to be applicable: low-cost, easy to machine or to shape, lightweight and low volume, mechanically and sufficiently chemically stable, and having a low contact resistance. Stainless steel is a low-cost material that is easy to shape, and thin sheets can be used to yield low volume and weight. Several stainless steels have been tested for their applicability. The compaction pressure is of large influence on the contact resistance. Also, the pretreatment of the surface is of influence; this is a permanent effect. Stainless steel constituents slowly dissolve into the membrane electrode assembly (MEA). It has been found that the anode side stainless steel flow plate is the main source of contamination. Direct contact between the stainless steel and the membrane greatly enhances the contaminant level. Using an appropriate pre-treatment and a coating or gasket preventing direct contact between stainless steel and the membrane, one alloy was found to satisfy the requirements for use as a low cost material for the flow plate of an SPFC.
07
ALTERNATIVE SOURCES Bioconversion
ENERGY
energy
00103467 Biological processes for mitigation of greenhouse gases Benemann, J. R. Greenhouse Gas Conlrol Technot.. Proc. In!. Con/, 4th, 1999, 689-693. Edited by Eliasson B. et al. Already human activities control and appropriate almost half the primary photosynthetic productivity of the planet. Better management of natural and man-made ecosystems affords many opportunities for mitigation of greenhouse gases, through sink enhancements, source reductions and substitution of fossil fuels with biofuels. Biofuels can be recovered from most organic wastes, from agricultural and forestry residues, and from biomass produced solely for energy use. However, the currently low costs of fossil fuels limits the markets for biofuels. Accounting for the greenhouse gas mitigation value of biofuels would significantly increase their contribution to world fuel supplies, estimated to be currently equivalent to about 15% of fossil fuel usage. Another limiting factor in expanding the use of biofuels is the relatively low solar energy conversion efficiencies of photosynthesis. Currently well below 1% of solar energy is converted into biomass energy even by intensive agricultural or forestry systems, with peak conversion efficiencies about Z-3% for sugar cane or microalgae cultures. One approach to increase photosynthetic efficiencies, being developed at the University of California Berkeley, is to reduce the amount of fightgathering chlorophyll in microalgae and higher plants. This would reduce mutual shading and also increase photosynthetic efficiencies under full sunlight intensities. Estimates of the potential of photosynthetic greenhouse mitigation processes vary widely. However, even conservative estimates for biofuels substituting for fossil fuels project the potential to reduce a large fraction of current increases in atmospheric COz levels. Biofuels production will require integration with existing agronomic, forestry and animal husbandry systems, and improved utilization-conversion processes. The diffuse nature of biomass resources requires relatively small-scale processes for their utilization as solid fuels or conversion to liquid and gaseous fuels. Earlier proposals for enormous energy plantations feeding large power plants, or for establishing huge ocean kelp farms, were impractical. As are some recent ‘geoengineering’ proposals, such as ocean fertilization. In biomass utilization, combustion is generally preferable to more complex processes, such as thermal or biochemical conversions to oils and alcohols. The co-firing of biomass in fossil power plants avoids many of the scale, procurement, and efficiency limitations of stand-alone systems and provides significant near-term opportunities for CO1 mitigation, Landfill gas recovery, due to the large greenhouse gas forcing of methane gas, is another currently available technology that can significantly reduce greenhouse gas emissions. Wastes and residues provide many opportunities for biofuels production and CO2 mitigation. Mitigating global warming with biological processes requires overcoming many scientific, technological, financial, institutional, regulatory and, perhaps most important, environmental barriers. This necessitates long-term and sustained research, development and implementation effort. 00103466 Biomass conversion: prospects and context Holt, N. A. and Van Der Burgt, M. J. VTT Symp., 1999, 192, 163-177. The prospects of biomass gasification are reviewed. The discussion focuses on the developments of biomass gasification, including biomass conversion, renewable energy and the demand for power, hydrogen, hydrocarbon fuels and organic chemicals. Special attention is being paid to the question of whether biomass gasification followed by combined cycle power generation is the best route for generating power from biomass. Alternatives comprising combustion and pyrolysis followed by combustion are discussed.
390
Fuel and Energy Abstracts
November 2000
00/03469 Biomass energy potential in Thailand Yokoyama, S. cl al. Biomass and Bioenergy, 2000, 18, (5), 405-410. An estimation of biomass energy potential including biomass residue and forestry biomass in Thailand was carried out taking into account the amount of biomass residue which has already been used and the possibility of biomass energy plantation in accordance with the National Plan of the Thai Government. According to this estimation, 65 PJ can be derived from agricultural and forestry waste and 770 PJ can be generated if half of the area allocated for cultivation of plantation forests could be used for biomass energy plantations. Today, biomass energy is 810 PJ, which is 30% of the total primary energy. 00103470 Biomass utilisation in liquid motor fuel production Gorlov, E. G. el al. Energy Environ., Proc. Trahzon Int. Energy Environ. Symp., 2nd, 1999, 331-332. Edited by Dincer I. and Ayhan T. The current world demand for energy is in the order of 11 milliard tonnes of conditional fuel. It is met approximately by 60% oil and gas, 30% coal and 10% by hydro and atomic energy. As a source of energy, plant biomass (woods and others) is also used in the order of 1 milliard tonnes of conditional fuel, or 0.7 milliard tonnes of oil equivalent. 00/03471 Catalytic production of biodiesel from soy-bean oil, used frying oil and tallow Alcantara, R. er al. Biomass and Bioenergy, 2000, 18, (6), 515-527. Three fatty materials, soy-bean oil, used frying oil and tallow, were transformed into two different types of biodiesel, by transesterification and amidation reactions with methanol and diethylamine, respectively. The ignition properties of these types of biodiesel were evaluated calculating the cetane index of the transesterification products, and the blending cetane number of the amide biodiesel blended with conventional diesel. Amide biodiesel enhances the ignition properties of the petrochemical diesel fuel, and it could account for the 5% market share that should be secured by biofuels by 2005. 00103472 Conversion of biomass and biomass-coal mixturesgasification, hot gas cleaning and gas turbine combustion Andries, J. et ~1. VTT. Symp., 1999, 192, 343-356. A 1.5 MWth process development unit is being used to perform a research programme in the field of energy production from solids. This installation is equipped with a pressurized, bubbling, fluidized bed gasifier, a high temperature ceramic channel-flow filter and a gas turbine combustor. The installation process is described and operational experience with the gasifier, the fuel gas and the ceramic filter is presented. Conversion of biomass and biomass-coal mixtures 00103473 gasification, hot gas cleaning and gas turbine combustion Andries, J. el crl. VTT. Symp., 1999, 192, 343-356. A 1.5 MWth process development unit is being used to perform a research programme in the field of energy production from solids. This installation is equipped with a pressurized, bubbling, fluidized bed gasifier, a high temperature ceramic channel-flow filter and a gas turbine combustor. The installation process is described and operational experience with the gasifier, the fuel gas and the ceramic filter is presented. 00103474 Countercurrent fixed-bed gasification of biomass at laboratory scale Di Blasi, C. er al. Ind Eng. Chem. Res., 1999, 38, (7), 2571-2581. The design and construction of a laboratory-scale counter-current, fixedbed gasification plant has taken place in order to produce data for process modelling and to compare the gasification characteristics of several biomasses (beechwood, nutshells, olive husks, and grape residues). The composition of producer gas and spatial temperature profiles have been measured for biomass gasification at different air flow rates. The gasheating value always attains a maximum as a function of this operating variable, associated with a decrease of the air-to-fuel ratio. Optimal gasification conditions of wood and agricultural residues give rise to comparable gas-heating values, comprised in the range 5-5.5 MJ/Nm3 with 28-30% CO, 5-7% COz, 6-8% Hz, l-2% CH4, and small amounts of Czhydrocarbons (apart from nitrogen). However, the gasification of agricultural residues is more difficult because of bed transport, partial ash sintering, non-uniform flow distribution, and the presence of a muddy phase in the effluents. For large-scale applications, proper pre-treatments are needed. 00103475 Energy potential of biomass in Ukraine Geletukha, G. G. and Martsenyuk, 2. A. Prom. Teplotekh., 1998, 20, (4), 52-55. (In Russian) In the Ukraine, biomass waste from cereal and technical crops, wood, and manure can be used as a raw material for energy production. Potentially, the biomass available for energy use was ~11.3 million ton of hydrocarbon fuel in 1995 (~5% of total energy demand in Ukraine). OOlO3476 Fuel and emission characteristics of sweet sorghum and sweet sorghum/lignite briquettes Ozdogan, S. cl al. Energy Environ., Proc. Tcahzon Inr. Energy Environ. Symp., Znd, 1999, 129-131. Edited by Dincer I. and Ayhan T.
energy sources (bioconversion
energy)
Bipolar plate materials for the solid polymer fuel cell (SPFC), alternative to the presently used graphite, should fulfil the following requirements in order to be applicable: low-cost, easy to machine or to shape, lightweight and low volume, mechanically and sufficiently chemically stable, and having a low contact resistance. Stainless steel is a low-cost material that is easy to shape, and thin sheets can be used to yield low volume and weight. Several stainless steels have been tested for their applicability. The compaction pressure is of large influence on the contact resistance. Also, the pretreatment of the surface is of influence; this is a permanent effect. Stainless steel constituents slowly dissolve into the membrane electrode assembly (MEA). It has been found that the anode side stainless steel flow plate is the main source of contamination. Direct contact between the stainless steel and the membrane greatly enhances the contaminant level. Using an appropriate pre-treatment and a coating or gasket preventing direct contact between stainless steel and the membrane, one alloy was found to satisfy the requirements for use as a low cost material for the flow plate of an SPFC.
07
ALTERNATIVE SOURCES Bioconversion
ENERGY
energy
00103467 Biological processes for mitigation of greenhouse gases Benemann, J. R. Greenhouse Gas Conlrol Technot.. Proc. In!. Con/, 4th, 1999, 689-693. Edited by Eliasson B. et al. Already human activities control and appropriate almost half the primary photosynthetic productivity of the planet. Better management of natural and man-made ecosystems affords many opportunities for mitigation of greenhouse gases, through sink enhancements, source reductions and substitution of fossil fuels with biofuels. Biofuels can be recovered from most organic wastes, from agricultural and forestry residues, and from biomass produced solely for energy use. However, the currently low costs of fossil fuels limits the markets for biofuels. Accounting for the greenhouse gas mitigation value of biofuels would significantly increase their contribution to world fuel supplies, estimated to be currently equivalent to about 15% of fossil fuel usage. Another limiting factor in expanding the use of biofuels is the relatively low solar energy conversion efficiencies of photosynthesis. Currently well below 1% of solar energy is converted into biomass energy even by intensive agricultural or forestry systems, with peak conversion efficiencies about Z-3% for sugar cane or microalgae cultures. One approach to increase photosynthetic efficiencies, being developed at the University of California Berkeley, is to reduce the amount of fightgathering chlorophyll in microalgae and higher plants. This would reduce mutual shading and also increase photosynthetic efficiencies under full sunlight intensities. Estimates of the potential of photosynthetic greenhouse mitigation processes vary widely. However, even conservative estimates for biofuels substituting for fossil fuels project the potential to reduce a large fraction of current increases in atmospheric COz levels. Biofuels production will require integration with existing agronomic, forestry and animal husbandry systems, and improved utilization-conversion processes. The diffuse nature of biomass resources requires relatively small-scale processes for their utilization as solid fuels or conversion to liquid and gaseous fuels. Earlier proposals for enormous energy plantations feeding large power plants, or for establishing huge ocean kelp farms, were impractical. As are some recent ‘geoengineering’ proposals, such as ocean fertilization. In biomass utilization, combustion is generally preferable to more complex processes, such as thermal or biochemical conversions to oils and alcohols. The co-firing of biomass in fossil power plants avoids many of the scale, procurement, and efficiency limitations of stand-alone systems and provides significant near-term opportunities for CO1 mitigation, Landfill gas recovery, due to the large greenhouse gas forcing of methane gas, is another currently available technology that can significantly reduce greenhouse gas emissions. Wastes and residues provide many opportunities for biofuels production and CO2 mitigation. Mitigating global warming with biological processes requires overcoming many scientific, technological, financial, institutional, regulatory and, perhaps most important, environmental barriers. This necessitates long-term and sustained research, development and implementation effort. 00103466 Biomass conversion: prospects and context Holt, N. A. and Van Der Burgt, M. J. VTT Symp., 1999, 192, 163-177. The prospects of biomass gasification are reviewed. The discussion focuses on the developments of biomass gasification, including biomass conversion, renewable energy and the demand for power, hydrogen, hydrocarbon fuels and organic chemicals. Special attention is being paid to the question of whether biomass gasification followed by combined cycle power generation is the best route for generating power from biomass. Alternatives comprising combustion and pyrolysis followed by combustion are discussed.
390
Fuel and Energy Abstracts
November 2000
00/03469 Biomass energy potential in Thailand Yokoyama, S. cl al. Biomass and Bioenergy, 2000, 18, (5), 405-410. An estimation of biomass energy potential including biomass residue and forestry biomass in Thailand was carried out taking into account the amount of biomass residue which has already been used and the possibility of biomass energy plantation in accordance with the National Plan of the Thai Government. According to this estimation, 65 PJ can be derived from agricultural and forestry waste and 770 PJ can be generated if half of the area allocated for cultivation of plantation forests could be used for biomass energy plantations. Today, biomass energy is 810 PJ, which is 30% of the total primary energy. 00103470 Biomass utilisation in liquid motor fuel production Gorlov, E. G. el al. Energy Environ., Proc. Trahzon Int. Energy Environ. Symp., 2nd, 1999, 331-332. Edited by Dincer I. and Ayhan T. The current world demand for energy is in the order of 11 milliard tonnes of conditional fuel. It is met approximately by 60% oil and gas, 30% coal and 10% by hydro and atomic energy. As a source of energy, plant biomass (woods and others) is also used in the order of 1 milliard tonnes of conditional fuel, or 0.7 milliard tonnes of oil equivalent. 00/03471 Catalytic production of biodiesel from soy-bean oil, used frying oil and tallow Alcantara, R. er al. Biomass and Bioenergy, 2000, 18, (6), 515-527. Three fatty materials, soy-bean oil, used frying oil and tallow, were transformed into two different types of biodiesel, by transesterification and amidation reactions with methanol and diethylamine, respectively. The ignition properties of these types of biodiesel were evaluated calculating the cetane index of the transesterification products, and the blending cetane number of the amide biodiesel blended with conventional diesel. Amide biodiesel enhances the ignition properties of the petrochemical diesel fuel, and it could account for the 5% market share that should be secured by biofuels by 2005. 00103472 Conversion of biomass and biomass-coal mixturesgasification, hot gas cleaning and gas turbine combustion Andries, J. et ~1. VTT. Symp., 1999, 192, 343-356. A 1.5 MWth process development unit is being used to perform a research programme in the field of energy production from solids. This installation is equipped with a pressurized, bubbling, fluidized bed gasifier, a high temperature ceramic channel-flow filter and a gas turbine combustor. The installation process is described and operational experience with the gasifier, the fuel gas and the ceramic filter is presented. Conversion of biomass and biomass-coal mixtures 00103473 gasification, hot gas cleaning and gas turbine combustion Andries, J. el crl. VTT. Symp., 1999, 192, 343-356. A 1.5 MWth process development unit is being used to perform a research programme in the field of energy production from solids. This installation is equipped with a pressurized, bubbling, fluidized bed gasifier, a high temperature ceramic channel-flow filter and a gas turbine combustor. The installation process is described and operational experience with the gasifier, the fuel gas and the ceramic filter is presented. 00103474 Countercurrent fixed-bed gasification of biomass at laboratory scale Di Blasi, C. er al. Ind Eng. Chem. Res., 1999, 38, (7), 2571-2581. The design and construction of a laboratory-scale counter-current, fixedbed gasification plant has taken place in order to produce data for process modelling and to compare the gasification characteristics of several biomasses (beechwood, nutshells, olive husks, and grape residues). The composition of producer gas and spatial temperature profiles have been measured for biomass gasification at different air flow rates. The gasheating value always attains a maximum as a function of this operating variable, associated with a decrease of the air-to-fuel ratio. Optimal gasification conditions of wood and agricultural residues give rise to comparable gas-heating values, comprised in the range 5-5.5 MJ/Nm3 with 28-30% CO, 5-7% COz, 6-8% Hz, l-2% CH4, and small amounts of Czhydrocarbons (apart from nitrogen). However, the gasification of agricultural residues is more difficult because of bed transport, partial ash sintering, non-uniform flow distribution, and the presence of a muddy phase in the effluents. For large-scale applications, proper pre-treatments are needed. 00103475 Energy potential of biomass in Ukraine Geletukha, G. G. and Martsenyuk, 2. A. Prom. Teplotekh., 1998, 20, (4), 52-55. (In Russian) In the Ukraine, biomass waste from cereal and technical crops, wood, and manure can be used as a raw material for energy production. Potentially, the biomass available for energy use was ~11.3 million ton of hydrocarbon fuel in 1995 (~5% of total energy demand in Ukraine). OOlO3476 Fuel and emission characteristics of sweet sorghum and sweet sorghum/lignite briquettes Ozdogan, S. cl al. Energy Environ., Proc. Tcahzon Inr. Energy Environ. Symp., Znd, 1999, 129-131. Edited by Dincer I. and Ayhan T.