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03775 Life cycle assessment of electricity production from poplar energy crops compared with conventional fossil fuels
07
quantity and methane percentage increased as the ambient temperature increased to the optimum temperature of about 35°C. Cattle manure was found to be the best animal waste and olive product waste the best plant waste for methane production. Fermenting organic waste and animal manure in particular resulted in an odourless fairly stabilized organic matter which could be used as soil conditioner and therefore protect the environment from a major source of pollution. The animal manure, which is considered a source of pollution and disturbance in the environment, could be converted into a source of energy in farms nearby, especially those away from the national electricity grid. The results showed that a family of four to five uersons living in the farm house can have sufficient source of enerev “, bv using such unit of 16 m3 for cooking and lighting. The cost analysk comparing the biogas costs with those of the market available LPG bottles showed a pay back period of about 20 years, which suggests the nonfeasibility of the units. Using such units in remote areas as oasis or mountainous farms will be highly valuable, especially in places lacking electrical connection. L
Evaluation of bioenergy resources with a global land use and energy model formulated with SD technique
99103766
Yamamoto, H. et al. Applied Energy, 1999, 63, (2) 101-113. Bioenergy is expected to become one of the key energy resources for global sustainable development. However, bioenergy cannot be infinite, because the land area available for biomass production is limited and a certain amount of biomass must be reserved for food and materials. The purpose of this study is to evaluate global bioenergy potential: for this purpose, the authors developed a global land-use and energy model (GLUE) formulated using a SD (system dynamics) technique. Through a simulation, the following results were obtained. (1) There will be a certain potential for energy crops harvested from surplus arable land in the developed regions of the world. However, care must be taken because the potential is sensitive to the global food supply and demand. (2) There will be a large bioenergy potential for biomass residues, such as cereal-harvesting residues, animal dune. roundwood felline residues and timber scrap. The ultimate bioenernv pot&tial, from all the Gomass residues, will be 577 U/year in AD 2100 G the world. (3) The mature-forest area in the developing regions decreases from 2.1 billion ha in 1990 to 0.8 billion ha in 2100. although it is assumed that the feiling area is reforested completely after AD 2025.?hus, there will not be much room to obtain more fuelwood from forests in the developing regions.
The Evritania (Greece) demonstration plant of biomass pyrolysis
99103769
Zabaniotou, A. A. and Karabelas, A. J. Biomass and Eioenergy, 1999, 16, (6), 431-445. The Evritania demonstration plant for pyrolysis of forestry biomass is described. Constructed in the village of Voulpi, district of Evritania, in Central Greece in 1995, the plant has a three-fold purpose: development of know-how, forest fire prevention and rural development. The products are charcoal and bio-oil. The plant capacity is 1200-1450 kg/h of wet biomass and the pyrolysis temperature is approximately 400°C. The raw material used is Arburus unedo, which is an evergreen broad-leaf tree which covers the area. Other agricultural waste could also be used, such as olive pits and cuttings, almond shells and cotton kernels. The paper includes the conceptual process flow sheet, the changes and improvements made during the trial phase, data from the start-up phase and product characteristics. Comparison of the process with the Alten process is presented. Additionally, comparisons are made of product characteristics with those from other pyrolysis processes. In general, the results obtained are encouraging, even though several improvements of the pilot plant are required.
Fermentation properties of agro-residues, leaf biomass and urban market garbage in a solid phase biogas fermenter
99103770
Chanakya, H. N. et al. Biomass and Bioenergy, 1999, 16, (6), 417-429. This laboratory study monitored the decomposition and gas production pattern of eight unprocessed biomass feedstocks representing annual weeds, leaf litter, agro residues and market wastes. Solid phase fermentation was effected with a weekly-fed biomass bed sprinkled twice daily with recycled fermentor liquid to initiate and sustain biogas production from the decomposing biomass bed. Fermentors were fed from the top with gradually increasing feed rates to determine maximum feed rates sustainable. Feed rates of 1 g total solids (TS) l-‘day-’ was possible which lead to pseudo-steady-state gas production rates between 0.26-0.98 ll-‘day-’ at specific gas vields of 0.18-0.44 I g-’ TS at 35-75% volatile solids (VS) destruct&. -During decomoositioi. bulkv biomass feedstocks underwent compaction and obiiated thk need ior a ire-treatment step. Bulk densities rose manifold to reach between 150-350 g I-’ within 20 days. A higher decomposition rate, process optimization and use of prk-compacted feedstocks have the potential to increase the feed rates and the quantity of feedstock held in the reactor, as well as gas production rates. The current gas production rates and space economy in these fermentors compare well with Indian cattle dung fermentors.
Alternative
energy sources (bioconversion
energy)
Formation of dioxin8 and other semi-volatile organic compounds in biomass combustion
99103771
Changer. H. K. et al. AD&. EnerPv. 1998. 60. (21. 101-114. Ide&fiecl in this work &e key a&mtag& of ‘u&g biofuels and biomass mixed with coal in combustion. With regard to land use, the availabilitv of biomass is reviewed, followed by a brief-account of the combustion proiess and the concomitant formation of semi-volatile organic compounds (SVOCs). The chemical compositions of selected biofuels and coal are presented. Routes of formation for polychlorinated dibenzodioxins/furans (dioxins and furans) are illustrated with subsequent reference to associated emissions. Graphs in the paper show coal and biofuel propensities for forming dioxin and furan isomers, followed by methods for predicting emission levels and isomer distributions within combustion systems. The final sections of the paper summarize recent equilibrium concentration studies and discuss the on-going combustion experiments being conducted in the University of Leeds’ Department of Fuel and Energy. Preliminary results are presented and discussed, finishing with three main experimentally drawn conclusions.
Gaseous nitrogen emissions for energy gain in the life of cereal crops
99103772
Freibauer, A. and Kaltschmitt, M. Umwehwiss. Schadst.-Forsch., 1998, 10, (61, 353-365. (In German) kith respect tb the resu&g environmental impacts, the release of volatile nitrogen species (NzO, NO,, NH4) was evaluated for the case of heat supply from-whoie cereal crops as a substitute for light oil products. The applied methodology of the life cycle assessment is discussed. The release of volatile nitrogen species and the resulting environmental impacts were subsequently quantified putting a special focus on the release of gases from biogenic sources in the agricultural ecosystem.
Improved pretreatment process for conversion of cellulose to fuel ethanol
99103773
Foody, B. et al. Eur. Pat. Appl. EP 884,391 (Cl. C12P7108). 16 Dee 1998, US Appl. 871,347, 9 Jun 1997,.22 pp. Enzyme treatment of cellulosic feedstocks to produce ethanol has been improved with a new pre-treatment method, making the process more economical. The improved pre-treatment comprises choosing either a feedstock with a ratio of r0.39 arabinoxylan to total non-starch polysaccharides (AX/NSP) or a selectively bred feedstock on the basis of an increased ratio of AXiNSP over a starting feedstock material. The reaction takes place at conditions that disrupt the fibre structure and hydrolyse a portion of the cellulose and hemicellulose. This pre-treatment produces a superior substrate for enzymic hydrolysis, by enabling the production of more glucose with less cellulose enzyme than any known procedures. 99103774 Kinetic study on hydrolysis of biomass (Ailanthus altissima chips) by using Alkaline-glycerol solution Kii@k, M. M. and Demirbas, A. Energy Convers. Manage., 1999, 40. (13). 1397-1403. This paper addresses the kinetics of biomass hydrolysis (Ailanthus altissima) using an aqueous alkaline-glycerol solution. The study was performed at four temperature levels (438,458,478 and 498 K) and for different times (1, 2, 3, 4, 5, 6, 7 and 8 hours). The solution concentration was constant (75 g glycerol, 25.0 g water, 10% NaOH and 10.0 g wood chips). After conversion has been determined, the fractional weight loss was found to be a function of the amount of wood residue and the reaction rate constant. The order of reaction and activation energy were calculated. The results were, respectively, 1.32 x lo-’ s-‘, 1.16, and 19.5 kJ mol-‘. 99103775 Life cycle assessment of electricity production from poplar energy crops compared with conventional fossil fuels
Rafaschieri, A. et al. Energy Comers. Manage., 1999, 40, (14), 1477-1493. A life cycle assessment approach is used to analyse the environmental impact of electric power production through an integrated gasification combined cycle (IGCC) fired by dedicated energy crops Iooular short rotation forkstry ‘(SRF)]. The r&sults are cornpar& with th’k alternative option of producing power by conventional fossil fuelled power plants. The energy and raw materials consumption and polluting emissions data both come from experimental cases. Thermodynamic models are applied for simulation of the energy conversion system. The results establish relative prooortions for both consumotion and emissions of the two enerev svstems. in detail. Considerable differknces emerge about the environmeiial’impaci caused by the different gasification conditions. The evaluation of the environmental effects of residues of the pesticides in ground/surface water and in the soil required particular care, as well as the characterization of all chemicals (herbicides, fungicides and insecticides) used for the crops.
Possibility of renewable energy production and CO2 mitigation by thermochemical liquefaction of mlcroalgae
99103776
Sawayama, S. et al. Biomass and Bioenergy, 1999, 17, (l), 33-39. The paper studies the energy balance and COz mitigating effect of a liquid fuel production process from microalgae using thermochemical liquefaction. Thermochemical liquefaction has the advantage of treating wet materials compared with direct combustion, gasification and pyrolysis, because it does not require a drying process. The yield of liquid fuel produced from Botryococcus braunii and its lower heating value were high
Fuel and Energy Abstracts
November 1999
397
quantity and methane percentage increased as the ambient temperature increased to the optimum temperature of about 35°C. Cattle manure was found to be the best animal waste and olive product waste the best plant waste for methane production. Fermenting organic waste and animal manure in particular resulted in an odourless fairly stabilized organic matter which could be used as soil conditioner and therefore protect the environment from a major source of pollution. The animal manure, which is considered a source of pollution and disturbance in the environment, could be converted into a source of energy in farms nearby, especially those away from the national electricity grid. The results showed that a family of four to five uersons living in the farm house can have sufficient source of enerev “, bv using such unit of 16 m3 for cooking and lighting. The cost analysk comparing the biogas costs with those of the market available LPG bottles showed a pay back period of about 20 years, which suggests the nonfeasibility of the units. Using such units in remote areas as oasis or mountainous farms will be highly valuable, especially in places lacking electrical connection. L
Evaluation of bioenergy resources with a global land use and energy model formulated with SD technique
99103766
Yamamoto, H. et al. Applied Energy, 1999, 63, (2) 101-113. Bioenergy is expected to become one of the key energy resources for global sustainable development. However, bioenergy cannot be infinite, because the land area available for biomass production is limited and a certain amount of biomass must be reserved for food and materials. The purpose of this study is to evaluate global bioenergy potential: for this purpose, the authors developed a global land-use and energy model (GLUE) formulated using a SD (system dynamics) technique. Through a simulation, the following results were obtained. (1) There will be a certain potential for energy crops harvested from surplus arable land in the developed regions of the world. However, care must be taken because the potential is sensitive to the global food supply and demand. (2) There will be a large bioenergy potential for biomass residues, such as cereal-harvesting residues, animal dune. roundwood felline residues and timber scrap. The ultimate bioenernv pot&tial, from all the Gomass residues, will be 577 U/year in AD 2100 G the world. (3) The mature-forest area in the developing regions decreases from 2.1 billion ha in 1990 to 0.8 billion ha in 2100. although it is assumed that the feiling area is reforested completely after AD 2025.?hus, there will not be much room to obtain more fuelwood from forests in the developing regions.
The Evritania (Greece) demonstration plant of biomass pyrolysis
99103769
Zabaniotou, A. A. and Karabelas, A. J. Biomass and Eioenergy, 1999, 16, (6), 431-445. The Evritania demonstration plant for pyrolysis of forestry biomass is described. Constructed in the village of Voulpi, district of Evritania, in Central Greece in 1995, the plant has a three-fold purpose: development of know-how, forest fire prevention and rural development. The products are charcoal and bio-oil. The plant capacity is 1200-1450 kg/h of wet biomass and the pyrolysis temperature is approximately 400°C. The raw material used is Arburus unedo, which is an evergreen broad-leaf tree which covers the area. Other agricultural waste could also be used, such as olive pits and cuttings, almond shells and cotton kernels. The paper includes the conceptual process flow sheet, the changes and improvements made during the trial phase, data from the start-up phase and product characteristics. Comparison of the process with the Alten process is presented. Additionally, comparisons are made of product characteristics with those from other pyrolysis processes. In general, the results obtained are encouraging, even though several improvements of the pilot plant are required.
Fermentation properties of agro-residues, leaf biomass and urban market garbage in a solid phase biogas fermenter
99103770
Chanakya, H. N. et al. Biomass and Bioenergy, 1999, 16, (6), 417-429. This laboratory study monitored the decomposition and gas production pattern of eight unprocessed biomass feedstocks representing annual weeds, leaf litter, agro residues and market wastes. Solid phase fermentation was effected with a weekly-fed biomass bed sprinkled twice daily with recycled fermentor liquid to initiate and sustain biogas production from the decomposing biomass bed. Fermentors were fed from the top with gradually increasing feed rates to determine maximum feed rates sustainable. Feed rates of 1 g total solids (TS) l-‘day-’ was possible which lead to pseudo-steady-state gas production rates between 0.26-0.98 ll-‘day-’ at specific gas vields of 0.18-0.44 I g-’ TS at 35-75% volatile solids (VS) destruct&. -During decomoositioi. bulkv biomass feedstocks underwent compaction and obiiated thk need ior a ire-treatment step. Bulk densities rose manifold to reach between 150-350 g I-’ within 20 days. A higher decomposition rate, process optimization and use of prk-compacted feedstocks have the potential to increase the feed rates and the quantity of feedstock held in the reactor, as well as gas production rates. The current gas production rates and space economy in these fermentors compare well with Indian cattle dung fermentors.
Alternative
energy sources (bioconversion
energy)
Formation of dioxin8 and other semi-volatile organic compounds in biomass combustion
99103771
Changer. H. K. et al. AD&. EnerPv. 1998. 60. (21. 101-114. Ide&fiecl in this work &e key a&mtag& of ‘u&g biofuels and biomass mixed with coal in combustion. With regard to land use, the availabilitv of biomass is reviewed, followed by a brief-account of the combustion proiess and the concomitant formation of semi-volatile organic compounds (SVOCs). The chemical compositions of selected biofuels and coal are presented. Routes of formation for polychlorinated dibenzodioxins/furans (dioxins and furans) are illustrated with subsequent reference to associated emissions. Graphs in the paper show coal and biofuel propensities for forming dioxin and furan isomers, followed by methods for predicting emission levels and isomer distributions within combustion systems. The final sections of the paper summarize recent equilibrium concentration studies and discuss the on-going combustion experiments being conducted in the University of Leeds’ Department of Fuel and Energy. Preliminary results are presented and discussed, finishing with three main experimentally drawn conclusions.
Gaseous nitrogen emissions for energy gain in the life of cereal crops
99103772
Freibauer, A. and Kaltschmitt, M. Umwehwiss. Schadst.-Forsch., 1998, 10, (61, 353-365. (In German) kith respect tb the resu&g environmental impacts, the release of volatile nitrogen species (NzO, NO,, NH4) was evaluated for the case of heat supply from-whoie cereal crops as a substitute for light oil products. The applied methodology of the life cycle assessment is discussed. The release of volatile nitrogen species and the resulting environmental impacts were subsequently quantified putting a special focus on the release of gases from biogenic sources in the agricultural ecosystem.
Improved pretreatment process for conversion of cellulose to fuel ethanol
99103773
Foody, B. et al. Eur. Pat. Appl. EP 884,391 (Cl. C12P7108). 16 Dee 1998, US Appl. 871,347, 9 Jun 1997,.22 pp. Enzyme treatment of cellulosic feedstocks to produce ethanol has been improved with a new pre-treatment method, making the process more economical. The improved pre-treatment comprises choosing either a feedstock with a ratio of r0.39 arabinoxylan to total non-starch polysaccharides (AX/NSP) or a selectively bred feedstock on the basis of an increased ratio of AXiNSP over a starting feedstock material. The reaction takes place at conditions that disrupt the fibre structure and hydrolyse a portion of the cellulose and hemicellulose. This pre-treatment produces a superior substrate for enzymic hydrolysis, by enabling the production of more glucose with less cellulose enzyme than any known procedures. 99103774 Kinetic study on hydrolysis of biomass (Ailanthus altissima chips) by using Alkaline-glycerol solution Kii@k, M. M. and Demirbas, A. Energy Convers. Manage., 1999, 40. (13). 1397-1403. This paper addresses the kinetics of biomass hydrolysis (Ailanthus altissima) using an aqueous alkaline-glycerol solution. The study was performed at four temperature levels (438,458,478 and 498 K) and for different times (1, 2, 3, 4, 5, 6, 7 and 8 hours). The solution concentration was constant (75 g glycerol, 25.0 g water, 10% NaOH and 10.0 g wood chips). After conversion has been determined, the fractional weight loss was found to be a function of the amount of wood residue and the reaction rate constant. The order of reaction and activation energy were calculated. The results were, respectively, 1.32 x lo-’ s-‘, 1.16, and 19.5 kJ mol-‘. 99103775 Life cycle assessment of electricity production from poplar energy crops compared with conventional fossil fuels
Rafaschieri, A. et al. Energy Comers. Manage., 1999, 40, (14), 1477-1493. A life cycle assessment approach is used to analyse the environmental impact of electric power production through an integrated gasification combined cycle (IGCC) fired by dedicated energy crops Iooular short rotation forkstry ‘(SRF)]. The r&sults are cornpar& with th’k alternative option of producing power by conventional fossil fuelled power plants. The energy and raw materials consumption and polluting emissions data both come from experimental cases. Thermodynamic models are applied for simulation of the energy conversion system. The results establish relative prooortions for both consumotion and emissions of the two enerev svstems. in detail. Considerable differknces emerge about the environmeiial’impaci caused by the different gasification conditions. The evaluation of the environmental effects of residues of the pesticides in ground/surface water and in the soil required particular care, as well as the characterization of all chemicals (herbicides, fungicides and insecticides) used for the crops.
Possibility of renewable energy production and CO2 mitigation by thermochemical liquefaction of mlcroalgae
99103776
Sawayama, S. et al. Biomass and Bioenergy, 1999, 17, (l), 33-39. The paper studies the energy balance and COz mitigating effect of a liquid fuel production process from microalgae using thermochemical liquefaction. Thermochemical liquefaction has the advantage of treating wet materials compared with direct combustion, gasification and pyrolysis, because it does not require a drying process. The yield of liquid fuel produced from Botryococcus braunii and its lower heating value were high
Fuel and Energy Abstracts
November 1999
397