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00178 Growth and production of a short rotation coppice culture of poplar. III. Second rotation results
07 Alternative energy sources (bioconversion energy) 06•00176 Grassland bird response to harvesting switchgrass as a biomass energy crop Roth, A. M. et al. Biomass and Bioenergy, 2005, 28, (5), 490 498. The combustion of perennial grass biomass to generate electricity may be a promising renewable energy option. Switchgrass (Panicum vitigatum) grown as a biofuel has the potential to provide a cash crop for farmers and quality nesting cover for grassland birds. In southwestern Wisconsin (near lat. 42°5U, long. 90°08~), the authors investigated the impact of an August harvest of switchgrass for bioenergy on community composition and abundance of Wisconsin grassland bird species of management concern. Harvesting the switchgrass in August resulted in changes in vegetation structure and bird species composition the following nesting season. In harvested transects, residual vegetation was shorter and the litter layer was reduced in the year following harvest. Grassland bird species that preferred vegetation of short to moderate height and low to moderate density were found in harvested areas. Unharvested areas provided tall, dense vegetation structure that was especially attractive to tall-grass bird species, such as sedge wren (Cistothorus platensis) and Henslow's sparrow (Ammodramus henslowii). When considering wildlife habitat value in harvest management of switchgrass for biofuel, leaving some fields unharvested each year would be a good compromise, providing some habitat for a larger number of grassland bird species of management concern than if all fields were harvested annually. In areas where most idle grassland habitat present on the landscape is tallgrass, harvest of switchgrass for biofuel has the potential to increase the local diversity of grassland birds.
06•00177 Growth and production of a short rotation coppice culture of poplar. I1. Clonal and year-to-year differences in leaf and petiole characteristics and stand leaf area index Alas, N. A. el al. Biomass and Bioenerf;y, 2005, 28, (6), 536 547. Twelve different poplar (Populus) clones, belonging to different species and interspecific hybrids were studied during the first and second growing seasons of the second rotation of a high density coppice culture. Leaf size, leaf area, leaf nitrogen and specific leaf area (SLA) were examined at two different canopy levels, together with petiole length and petiole diameter. Leaves in the upper canopy layer were larger, heavier and had a lower SLA. They also had longer and thicker petioles, as well as a higher nitrogen concentration per unit dry weight than lower canopy leaves. Significant clonal variation was observed in leaf and petiole characteristics in both growing seasons. Leaf area index (LAI), scaled-up from allometric relationships, showed significant clonal variation in the two growing seasons, and increased for all clones in the second growing season. LAI increment was related to a significantly increased diameter of all shoots. The study demonstrates (i) that light significantly affects leaf and petiolar characteristics, and nitrogen concentrations of foliage elements, and (ii) that year-to-year differences in foliar characteristics are related to stand aging rather than to increased shading due to larger LAI.
06•00178 Growth and production of a short rotation coppice culture of poplar. II1. Second rotation results Laureysens, I. et al. Biomass and Bioenergy, 2005, 29, (1), 10 21. This study describes production and growth of the second rotation of 17 poplar (Populus spp.) clones in a short rotation coppice culture (SRC). In addition, the link with leaf characteristics was studied. In April 1996, an experimental field plantation with 10,000 cuttings ha 1 was established on a former waste disposal site. In December 1996, January 2001 and February 2004, all stools were coppiced. At the end of the second rotation (2001 2003), highest biomass production was found for P. nigra clone Wolterson with 9.7 Mg ha 1 y 1. The best performers of the first rotation, i.e.P, lrichocatTax P. deltoides clones Hoogvorst and Hazendans, performed poorly in the second rotation, due to heavy rust infections. Two growth strategies were evident: Wolterson had a slow elimination of smaller shoots and had lots of smaller leaves; Hazendans and Hoogvorst had a rapid elimination of smaller shoots and had fewer, larger leaves. The paper concludes that shoot growth dynamics and leaf size were not the primary production determinants in the poplar SRC. But Melampsora larici-populina remained an important external determinant of biomass production.
06•00179 Herb layer productivity under different light gaps in the forets of Western Ghats of Karnataka, India Bhat, D.M. el al. Int. J. Agrieullural Resources, Governance and Ecology, 2005, 4, (1), 93 100. A productivity estimation of tree, shrub and herb layer biomass was undertaken in Uttara Kannada, a Western Ghats district in Kamataka in differentially managed forests. In addition to biomass, light gap in these sample sites was also estimated to understand the relationship between the light interception pattern at different canopy layers and their productivity. The studies indicate that tree biomass productivity decreases and herb productivity increases with increasing light gap. However, the herb biomass productivity attains maximum height at 40-
26
Fuel and Energy Abstracts
January 2006
60% light gaps than in plots with no trees or 100% light gap indicating that highest herb biomass is found in forests managed for leaf manure than in grasslands. This further indicates that partial shading enhances herb layer productivity. Thus, a strategy of undertaking agroforestry in villages to enhance the total biomass productivity to meet the needs of the villages was suggested.
06•00180 Immobilized Pseudomonas cepacia lipase for biodiesel fuel production from soybean oil Noureddini, H. et al. Bioresouree Technology, 2005, 96, (7), 769 777. Enzymatic transesterification of soybean oil with methanol and ethanol was studied. Of the nine lipases that were tested in the initial screening, lipase PS from Pseudomonas cepacia resulted in the highest yield of alkyl esters. Lipase from Pseudomonas cepacia was further investigated in immobilized form within a chemically inert, hydrophobic sol gel support. The gel-entrapped lipase was prepared by polycondensation of hydrolysed tetralnethoxysilane and iso-butyltrilnethoxysilane. Using the immobilized lipase PS, the effects of water and alcohol concentration, enzyme loading, enzyme thermal stability, and temperature in the transesterification reaction were investigated. The optimal conditions for processing 10 g of soybean oil were: 35~'C, 1:7.5 oil/ methanol molar ratio, 0.5 g water and 475 1rig lipase for the reactions with methanol, and 35°C, 1:15.2 oil/ethanol molar ratio, 0.3 g water, 475 nag lipase for the reactions with ethanol. Subject to the optimal conditions, methyl and ethyl esters formation of 67 and 65 tool% in 1 h of reaction were obtained for the immobilized enzyme reactions. Upon the reaction with the immobilized lipase, the triglycerides reached negligible levels after the first 30 rain of the reaction and the immobilized lipase was consistently more active than the free enzyme. The immobilized lipase also proved to be stable and lost little activity when was subjected to repeated uses.
06•00181 Influence of operating conditions and the role of sulfur in the formation of aerosols from biomass combustion Jimdnez, S. and Ballester, J. Combustion and Flame, 2005, 140, (4), 346 358. The properties of the fine particles generated from burning biomass have been experimentally studied in a laboratory facility under a variety of combustion and postcombustion conditions; the parameters varied include combustion temperature and the concentrations of oxygen and SO2 in the flue gases. SO2 was added as a pure gas or generated in cofiring experiments. Fine particles are composed only of K, el, and S, in the form of potassium sulfate and chloride, except for the tests at 1450°C, where phosphorus appeared also in significant amounts, although the species in which it was contained could not be determined exactly. From previous studies, K2SO 4 is known to nucleate first when the gas cools, KC1 condensing on these nuclei at lower temperatures. The chloride/sulfate ratio in fine particles is shown here to be greatly affected by the initial [SO2] and [02] in the flue gases; this dependence can be adequately modeled if the conversion of SO2 to SO3 is assumed to be the only limiting step in the route to K2SO4 formation. Evidence for such a kinetic limitation is provided. Both the experimental results and theoretical considerations show that the presence of C1 in the submicron particles, associated with severe boiler corrosion, can be at least partly avoided with adequate combustion strategies (e.g. cofiring). The properties of coarse (>1 ~tm) particles have also been studied; both their chemical composition and size distribution are consistent with the break-up model of fly-ash formation.
06•00182 Modeling circulating fluidized bed biomass gasifiers. A pseudo-rigorous model for stationary state Corella, J. and Sanz, A. Fuel Processing Teehnology, 2005, 86, (9), 1021 1053. A l-dimensional model for an atmospheric circulating fluidized bed biomass gasifier (CFBBG) under stationary state is presented in this paper. The model is based on the kinetic equations for the reaction network solved together with mass and heat balances and with several hydrodynamic considerations. Kinetics used include both the authors' own kinetic data and published equations with some corrective factors. The reaction network used involves 12 different reactions. A sub-model for the tar generation-elimination in the CFBBG is included in the whole model. The model has an academic structure, but several assumptions were made because of lack of accurate data in some areas. The overall model has some empirical aspects and can therefore be considered as semi-rigorous. Hydrodynamics in the model were checked with a survey carried out worldwide among the existing pilot and commercial CFBBGs. The axial profiles of concentration of ten different species (H2, CO, CO2, tar, char, etc.) and temperature can be calculated with this model which was conceived to optimize both design and operation of CFBBGs.
06•00183 Robust control for fuel cell-microturbine hybrid power plant using biomass Jurado, F. Energ;y, 2005, 30, (10), 1711 1727.
06•00177 Growth and production of a short rotation coppice culture of poplar. I1. Clonal and year-to-year differences in leaf and petiole characteristics and stand leaf area index Alas, N. A. el al. Biomass and Bioenerf;y, 2005, 28, (6), 536 547. Twelve different poplar (Populus) clones, belonging to different species and interspecific hybrids were studied during the first and second growing seasons of the second rotation of a high density coppice culture. Leaf size, leaf area, leaf nitrogen and specific leaf area (SLA) were examined at two different canopy levels, together with petiole length and petiole diameter. Leaves in the upper canopy layer were larger, heavier and had a lower SLA. They also had longer and thicker petioles, as well as a higher nitrogen concentration per unit dry weight than lower canopy leaves. Significant clonal variation was observed in leaf and petiole characteristics in both growing seasons. Leaf area index (LAI), scaled-up from allometric relationships, showed significant clonal variation in the two growing seasons, and increased for all clones in the second growing season. LAI increment was related to a significantly increased diameter of all shoots. The study demonstrates (i) that light significantly affects leaf and petiolar characteristics, and nitrogen concentrations of foliage elements, and (ii) that year-to-year differences in foliar characteristics are related to stand aging rather than to increased shading due to larger LAI.
06•00178 Growth and production of a short rotation coppice culture of poplar. II1. Second rotation results Laureysens, I. et al. Biomass and Bioenergy, 2005, 29, (1), 10 21. This study describes production and growth of the second rotation of 17 poplar (Populus spp.) clones in a short rotation coppice culture (SRC). In addition, the link with leaf characteristics was studied. In April 1996, an experimental field plantation with 10,000 cuttings ha 1 was established on a former waste disposal site. In December 1996, January 2001 and February 2004, all stools were coppiced. At the end of the second rotation (2001 2003), highest biomass production was found for P. nigra clone Wolterson with 9.7 Mg ha 1 y 1. The best performers of the first rotation, i.e.P, lrichocatTax P. deltoides clones Hoogvorst and Hazendans, performed poorly in the second rotation, due to heavy rust infections. Two growth strategies were evident: Wolterson had a slow elimination of smaller shoots and had lots of smaller leaves; Hazendans and Hoogvorst had a rapid elimination of smaller shoots and had fewer, larger leaves. The paper concludes that shoot growth dynamics and leaf size were not the primary production determinants in the poplar SRC. But Melampsora larici-populina remained an important external determinant of biomass production.
06•00179 Herb layer productivity under different light gaps in the forets of Western Ghats of Karnataka, India Bhat, D.M. el al. Int. J. Agrieullural Resources, Governance and Ecology, 2005, 4, (1), 93 100. A productivity estimation of tree, shrub and herb layer biomass was undertaken in Uttara Kannada, a Western Ghats district in Kamataka in differentially managed forests. In addition to biomass, light gap in these sample sites was also estimated to understand the relationship between the light interception pattern at different canopy layers and their productivity. The studies indicate that tree biomass productivity decreases and herb productivity increases with increasing light gap. However, the herb biomass productivity attains maximum height at 40-
26
Fuel and Energy Abstracts
January 2006
60% light gaps than in plots with no trees or 100% light gap indicating that highest herb biomass is found in forests managed for leaf manure than in grasslands. This further indicates that partial shading enhances herb layer productivity. Thus, a strategy of undertaking agroforestry in villages to enhance the total biomass productivity to meet the needs of the villages was suggested.
06•00180 Immobilized Pseudomonas cepacia lipase for biodiesel fuel production from soybean oil Noureddini, H. et al. Bioresouree Technology, 2005, 96, (7), 769 777. Enzymatic transesterification of soybean oil with methanol and ethanol was studied. Of the nine lipases that were tested in the initial screening, lipase PS from Pseudomonas cepacia resulted in the highest yield of alkyl esters. Lipase from Pseudomonas cepacia was further investigated in immobilized form within a chemically inert, hydrophobic sol gel support. The gel-entrapped lipase was prepared by polycondensation of hydrolysed tetralnethoxysilane and iso-butyltrilnethoxysilane. Using the immobilized lipase PS, the effects of water and alcohol concentration, enzyme loading, enzyme thermal stability, and temperature in the transesterification reaction were investigated. The optimal conditions for processing 10 g of soybean oil were: 35~'C, 1:7.5 oil/ methanol molar ratio, 0.5 g water and 475 1rig lipase for the reactions with methanol, and 35°C, 1:15.2 oil/ethanol molar ratio, 0.3 g water, 475 nag lipase for the reactions with ethanol. Subject to the optimal conditions, methyl and ethyl esters formation of 67 and 65 tool% in 1 h of reaction were obtained for the immobilized enzyme reactions. Upon the reaction with the immobilized lipase, the triglycerides reached negligible levels after the first 30 rain of the reaction and the immobilized lipase was consistently more active than the free enzyme. The immobilized lipase also proved to be stable and lost little activity when was subjected to repeated uses.
06•00181 Influence of operating conditions and the role of sulfur in the formation of aerosols from biomass combustion Jimdnez, S. and Ballester, J. Combustion and Flame, 2005, 140, (4), 346 358. The properties of the fine particles generated from burning biomass have been experimentally studied in a laboratory facility under a variety of combustion and postcombustion conditions; the parameters varied include combustion temperature and the concentrations of oxygen and SO2 in the flue gases. SO2 was added as a pure gas or generated in cofiring experiments. Fine particles are composed only of K, el, and S, in the form of potassium sulfate and chloride, except for the tests at 1450°C, where phosphorus appeared also in significant amounts, although the species in which it was contained could not be determined exactly. From previous studies, K2SO 4 is known to nucleate first when the gas cools, KC1 condensing on these nuclei at lower temperatures. The chloride/sulfate ratio in fine particles is shown here to be greatly affected by the initial [SO2] and [02] in the flue gases; this dependence can be adequately modeled if the conversion of SO2 to SO3 is assumed to be the only limiting step in the route to K2SO4 formation. Evidence for such a kinetic limitation is provided. Both the experimental results and theoretical considerations show that the presence of C1 in the submicron particles, associated with severe boiler corrosion, can be at least partly avoided with adequate combustion strategies (e.g. cofiring). The properties of coarse (>1 ~tm) particles have also been studied; both their chemical composition and size distribution are consistent with the break-up model of fly-ash formation.
06•00182 Modeling circulating fluidized bed biomass gasifiers. A pseudo-rigorous model for stationary state Corella, J. and Sanz, A. Fuel Processing Teehnology, 2005, 86, (9), 1021 1053. A l-dimensional model for an atmospheric circulating fluidized bed biomass gasifier (CFBBG) under stationary state is presented in this paper. The model is based on the kinetic equations for the reaction network solved together with mass and heat balances and with several hydrodynamic considerations. Kinetics used include both the authors' own kinetic data and published equations with some corrective factors. The reaction network used involves 12 different reactions. A sub-model for the tar generation-elimination in the CFBBG is included in the whole model. The model has an academic structure, but several assumptions were made because of lack of accurate data in some areas. The overall model has some empirical aspects and can therefore be considered as semi-rigorous. Hydrodynamics in the model were checked with a survey carried out worldwide among the existing pilot and commercial CFBBGs. The axial profiles of concentration of ten different species (H2, CO, CO2, tar, char, etc.) and temperature can be calculated with this model which was conceived to optimize both design and operation of CFBBGs.
06•00183 Robust control for fuel cell-microturbine hybrid power plant using biomass Jurado, F. Energ;y, 2005, 30, (10), 1711 1727.