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02933 Polycyclic aromatic hydrocarbons in catalytically upgraded biomass pyrolysis oils
07 fraction of SOZ in the gas was well below IO-’ before cooling to 700°C at 4 atm and before 800°C at IO atm. Even by almost doubling the sulfur, it was below this limit before cooling to 600°C indicating a buffering effect of the assemblage of condensates and the gas. Measured sulfur additions to the basic inorganic materials in burning wood should improve the performance of wood in combustors. If the solids produced can be separated from the gas by a cyclone and/or filters, sulfur additions might make aspen wood a reasonable candidate for fuelling an efficient turbine.
97t0292a The wheat straw
inorganic
chemistry
of the
combustion
of
Blander, M. and Pelton, A. D. Biomass and Bioeneqg, 1997, 12, (4). 295298. The authors carried out equilibrium calculations of the combustion of wheat straw in an excess of air at 1 atm at temperatures ranging from 5001200°C. A low melting molten silicate was present at all temperatures which, in addition to a large concentration of silica (76-83 mol%) and potassium (IO-12 mol%) contained small concentrations (~5 mol%) of calcium, sodium, magnesium and aluminium oxides as well as small amounts of chloride, sulfate and carbonate. This liquid is the probable cause of problems with fouling and corrosion in combustors using wheat straw. The identification of this liquid is an aid in deducing solutions to these problems.
Kinetic NO, 97to2929 from single wood particle
modelling and combustion
experimental
results
Skreiberg, 0. t’t al. Fuel, 1997, 76, (7), 671-682. In order to investigate the NO emission level from single wood particle combustion, batch combustion experiments were performed in an electrically heated small-scale fixed-bed reactor. An extensive homogeneous kinetic modelling study was carried out to verify and explain the experimental results. In general, the NO, emission level increases with an increasing excess air ratio. However, it may show a maximum as a function of temperature, for both experimental and modelling results.
Life cycle 97to2930 environmental aspects
analysis
of
biofuels
under
different
Kaltschmitt, M. et al. Biomas.s and Bioenergy, 1997, 12, (2), 121-134. With the help of life cycle analysis, the environmental impact of bioenergy carriers can be determined. The present study shows that bioenergy carriers offer some clear ecological advantages over fossil fuels, such as conserving fossil energy resources or reducing the greenhouse effect, but they also have some definite disadvantages, e.g. certain airborne pollutants, when the overall life cycle is considered. The paper first discusses the methodological approach for conducting a Life Cycle Analysis (LCA) for biofuels; this approach is then used for a case study of Rape Methyl Ester (RME) compared with diesel fuel. The same approach is then applied for some bioenergy routes discussed currently in Germany. For the different bioenergy routes the results of the ECA for Energy. COZ equivalents, N?O emissions, SO2 equivalents SO2 emissions and NO, emissions are given and discussed.
Liquefaction of biomass in the presence 97to2931 and Hz0 using alkalis and salts as the catalyst
of phenol
Maldas, D. and Shiraisri, N. Biomasr and Bioenergy, 1997, 12, (4), 27327’). The paper reports the results of this experimental study. The reaction conditions, mainly pH and temperature, as well as type of biomass sample, hydrating power and chelating power, particularly for transition metals, of metal ions were found have a profound influence on the extent of dissolution of biomass in phenol.
Modeling biomass pyrolysis kinetics and 97to2932 mechanisms Ch:;~~y. et al. Prep-. Pap. Am. Chem. Sot., Div. Fuel Chew., 1997, 42, (l), Emphasis on the production of chemicals and liquid fuels from biomass will be renewed over the next ten years on the use of agricultural wastes as feedstocks, and the co-firing of coal and biomass materials. In view of the tremendous diversity of biomass feedstocks, there exists a great need for a robust, comprehensive model that could be utilized to predict the composition and properties of pyrolysis products as a function of feedstock characteristics and process conditions. The objective of this work is to adapt an existing coal pyrolysis model and make it suitable for biomass pyrolysis. This approach is sound due to the numerous similarities between biomass and coal. There are important differences, however, which preclude direct application of the coal model. This work involved: (I) selection of a set of materials representing the main types of biomass; (2) development of a biomass classification scheme; (3) development of amodelling approach based on modifications of a coal pyrolysis model; (4) calibration of the model for a set of standard materials against pyrolysis data taken over a range of heating rates; (5) validation of the model against pyrolysis data taken under other heating rate conditions.
97to2933 upgraded
Alternative
energy sources (bioconversion
energy)
Polycyclic aromatic hydrocarbons in catalytically biomass pyrolysis oils P. T. and Home, P. A. J. Inst. Energy, December 1996,481, 176-
Williams, 191. The fluidized-bed pyrolysis of biomass at 55O’C was studied. The evolved pyrolysis vapours were passed over a fixed-bed of zeolite ZSM-5 catalyst placed in the freeboard of the reactor. The influence of pyrolysis and catalyst temperature, of catalyst ageing and regeneration and the vapour residence time of the catalyst on the polycyclic aromatic hydrocarbons concentration was investigated.
97to2934 Processing and utilizing urban wood waste and pallets for fuel Smith, M. L. Proc. Biomass Conf. Am.: Emqs, EnL,irorl., Agric. fad.. Znd, 1995, IlO-119. The potential for recovering, processing and utilizing a number of urban waste materials and selected manufacturing waste for fuel is currently being investigated. The emphasis is on relatively clean, low ash, high BTU Urban Fuels that might be obtained at substantially reduced cost over conventional fuels. Results from recently completed studies by the Council of Great Lakes Governors Regional Binmass Energy Program, show urban wood waste to be an important source of energy comparing favourably to other urban waste fuels. The GLRBEP Studies. which are reviewed in this paper, examined the types, quantities, current disposition, energy potential and potential markets for urban wood waste in large Metropolitan areas of a five state region including Illinois, Iowa, Minnesota, Ohio and Wisconsin. Net costs to make urban wood fuel available and avoided disposal costs are reviewed. Incentives, methods of sorting and opportunities to salvage urban wood waste and other combustible waste are also discussed. Urban wood fuels are compared to other urban waste fuels.
97to2935 Properties for power production
of Danish biofuels
and the requirements
Sander, B. L3lomas.p and Bioenergy, 1997, 12. (3). 177-183. Straw and wood chips are the most abundant biofuels in Denmark, and an overview of fuel composition in comparison with coal is given. The high content of potassium and chlorine in straw causes a number of serious technical problems in power production plants and therefore the possibility of reducing the content of potassium and chlorine in straw has been investigated. Cultivation trials were established in the growing seasons of 1993 and 1994. In the first part of the project, the wa,y in which different cultivation factors influence the chemical composltion of straw was investigated. The effect of chlorine supply with fertilizers on straw composition was also studied. No correlation was found between the content of potassium and chlorine in straw and soil type, nitrogen and potassium fertilizer dose, pesticide dose and geographic location, but a strong correlation existed between chlorine content in straw and supply of chlorine with fertilizer. The study concluded that the variety determines the content of potassium and chlorine and grain has a lower content of ash, K, Ca. Si and Cl than straw, but a higher content of N.
97tO2936 mechanisms
Relating catalytic coal or biomass to plant capital cost components
gasification
Hauserman, W. B. ItIt. J. Hydrogen Energy, 1997, 22. (4), 409-414. Equipment selection for HZ production from biomass or coal is dominated by whether the process intent is to maximize pyrolysis and subsequent cracking or to maximize steam-semicoke or steam-char gasification. Benchscale methods are discussed in order to predict which approach is best suited to specific coals or biomass materials. Either reaction mode can be greatly enhanced by use of various catalysts, which adds a major economic dimension to process selection and design. Bench-scale methodology is presented to determine proportions of Hr and CH., from pyrolysis and gasification reactions, with criteria for relating the?e results to capital cost components of catalytic options in full-scale processes. The author claims that catalyst evaluations should not be based on steam-char (or cteamsemicoke) reactivity measurements alone, especially for biomass and for low-rank coal with high volatile material content.
97to2937 feedstocks
Removal of by mechanical
inorganic constituents of dewatering and leaching
biomass
Turn, S. Q. et al. Biomass and BioenerR), 1997. 12, (4), 241-252. The authors state that inorganic constituents of ash in biomass fuels are responsible for equipment failure and operating difficulties in thermochemical energy conversion facilities. Alkali metals, in the presence of chlorine and sulfur, are the leading contributors to this problem. Banagrass, a herbaceous species being considered for use as a dedicated energy crop, contains high levels of potassium and chlorine. Some inorganic elements are water soluble and the opportunity exists to remove them by mechanical dewatering and leaching as part of the feedstock preparation process. Laboratory-scale equipment, representative of processes employed in the commercial extraction of sugar from cane, was used to prepare banagrass fuel treatments. These included two degrees of comminution and two dewatering schemes. It is concluded that banagrass subjected to the most severe treatment, fine comminution with multi-step dewatering, should produce a boiler fuel with characteristics similar to those of baggasse.
Fuel and Energy Abstracts
July 1997
241
97t0292a The wheat straw
inorganic
chemistry
of the
combustion
of
Blander, M. and Pelton, A. D. Biomass and Bioeneqg, 1997, 12, (4). 295298. The authors carried out equilibrium calculations of the combustion of wheat straw in an excess of air at 1 atm at temperatures ranging from 5001200°C. A low melting molten silicate was present at all temperatures which, in addition to a large concentration of silica (76-83 mol%) and potassium (IO-12 mol%) contained small concentrations (~5 mol%) of calcium, sodium, magnesium and aluminium oxides as well as small amounts of chloride, sulfate and carbonate. This liquid is the probable cause of problems with fouling and corrosion in combustors using wheat straw. The identification of this liquid is an aid in deducing solutions to these problems.
Kinetic NO, 97to2929 from single wood particle
modelling and combustion
experimental
results
Skreiberg, 0. t’t al. Fuel, 1997, 76, (7), 671-682. In order to investigate the NO emission level from single wood particle combustion, batch combustion experiments were performed in an electrically heated small-scale fixed-bed reactor. An extensive homogeneous kinetic modelling study was carried out to verify and explain the experimental results. In general, the NO, emission level increases with an increasing excess air ratio. However, it may show a maximum as a function of temperature, for both experimental and modelling results.
Life cycle 97to2930 environmental aspects
analysis
of
biofuels
under
different
Kaltschmitt, M. et al. Biomas.s and Bioenergy, 1997, 12, (2), 121-134. With the help of life cycle analysis, the environmental impact of bioenergy carriers can be determined. The present study shows that bioenergy carriers offer some clear ecological advantages over fossil fuels, such as conserving fossil energy resources or reducing the greenhouse effect, but they also have some definite disadvantages, e.g. certain airborne pollutants, when the overall life cycle is considered. The paper first discusses the methodological approach for conducting a Life Cycle Analysis (LCA) for biofuels; this approach is then used for a case study of Rape Methyl Ester (RME) compared with diesel fuel. The same approach is then applied for some bioenergy routes discussed currently in Germany. For the different bioenergy routes the results of the ECA for Energy. COZ equivalents, N?O emissions, SO2 equivalents SO2 emissions and NO, emissions are given and discussed.
Liquefaction of biomass in the presence 97to2931 and Hz0 using alkalis and salts as the catalyst
of phenol
Maldas, D. and Shiraisri, N. Biomasr and Bioenergy, 1997, 12, (4), 27327’). The paper reports the results of this experimental study. The reaction conditions, mainly pH and temperature, as well as type of biomass sample, hydrating power and chelating power, particularly for transition metals, of metal ions were found have a profound influence on the extent of dissolution of biomass in phenol.
Modeling biomass pyrolysis kinetics and 97to2932 mechanisms Ch:;~~y. et al. Prep-. Pap. Am. Chem. Sot., Div. Fuel Chew., 1997, 42, (l), Emphasis on the production of chemicals and liquid fuels from biomass will be renewed over the next ten years on the use of agricultural wastes as feedstocks, and the co-firing of coal and biomass materials. In view of the tremendous diversity of biomass feedstocks, there exists a great need for a robust, comprehensive model that could be utilized to predict the composition and properties of pyrolysis products as a function of feedstock characteristics and process conditions. The objective of this work is to adapt an existing coal pyrolysis model and make it suitable for biomass pyrolysis. This approach is sound due to the numerous similarities between biomass and coal. There are important differences, however, which preclude direct application of the coal model. This work involved: (I) selection of a set of materials representing the main types of biomass; (2) development of a biomass classification scheme; (3) development of amodelling approach based on modifications of a coal pyrolysis model; (4) calibration of the model for a set of standard materials against pyrolysis data taken over a range of heating rates; (5) validation of the model against pyrolysis data taken under other heating rate conditions.
97to2933 upgraded
Alternative
energy sources (bioconversion
energy)
Polycyclic aromatic hydrocarbons in catalytically biomass pyrolysis oils P. T. and Home, P. A. J. Inst. Energy, December 1996,481, 176-
Williams, 191. The fluidized-bed pyrolysis of biomass at 55O’C was studied. The evolved pyrolysis vapours were passed over a fixed-bed of zeolite ZSM-5 catalyst placed in the freeboard of the reactor. The influence of pyrolysis and catalyst temperature, of catalyst ageing and regeneration and the vapour residence time of the catalyst on the polycyclic aromatic hydrocarbons concentration was investigated.
97to2934 Processing and utilizing urban wood waste and pallets for fuel Smith, M. L. Proc. Biomass Conf. Am.: Emqs, EnL,irorl., Agric. fad.. Znd, 1995, IlO-119. The potential for recovering, processing and utilizing a number of urban waste materials and selected manufacturing waste for fuel is currently being investigated. The emphasis is on relatively clean, low ash, high BTU Urban Fuels that might be obtained at substantially reduced cost over conventional fuels. Results from recently completed studies by the Council of Great Lakes Governors Regional Binmass Energy Program, show urban wood waste to be an important source of energy comparing favourably to other urban waste fuels. The GLRBEP Studies. which are reviewed in this paper, examined the types, quantities, current disposition, energy potential and potential markets for urban wood waste in large Metropolitan areas of a five state region including Illinois, Iowa, Minnesota, Ohio and Wisconsin. Net costs to make urban wood fuel available and avoided disposal costs are reviewed. Incentives, methods of sorting and opportunities to salvage urban wood waste and other combustible waste are also discussed. Urban wood fuels are compared to other urban waste fuels.
97to2935 Properties for power production
of Danish biofuels
and the requirements
Sander, B. L3lomas.p and Bioenergy, 1997, 12. (3). 177-183. Straw and wood chips are the most abundant biofuels in Denmark, and an overview of fuel composition in comparison with coal is given. The high content of potassium and chlorine in straw causes a number of serious technical problems in power production plants and therefore the possibility of reducing the content of potassium and chlorine in straw has been investigated. Cultivation trials were established in the growing seasons of 1993 and 1994. In the first part of the project, the wa,y in which different cultivation factors influence the chemical composltion of straw was investigated. The effect of chlorine supply with fertilizers on straw composition was also studied. No correlation was found between the content of potassium and chlorine in straw and soil type, nitrogen and potassium fertilizer dose, pesticide dose and geographic location, but a strong correlation existed between chlorine content in straw and supply of chlorine with fertilizer. The study concluded that the variety determines the content of potassium and chlorine and grain has a lower content of ash, K, Ca. Si and Cl than straw, but a higher content of N.
97tO2936 mechanisms
Relating catalytic coal or biomass to plant capital cost components
gasification
Hauserman, W. B. ItIt. J. Hydrogen Energy, 1997, 22. (4), 409-414. Equipment selection for HZ production from biomass or coal is dominated by whether the process intent is to maximize pyrolysis and subsequent cracking or to maximize steam-semicoke or steam-char gasification. Benchscale methods are discussed in order to predict which approach is best suited to specific coals or biomass materials. Either reaction mode can be greatly enhanced by use of various catalysts, which adds a major economic dimension to process selection and design. Bench-scale methodology is presented to determine proportions of Hr and CH., from pyrolysis and gasification reactions, with criteria for relating the?e results to capital cost components of catalytic options in full-scale processes. The author claims that catalyst evaluations should not be based on steam-char (or cteamsemicoke) reactivity measurements alone, especially for biomass and for low-rank coal with high volatile material content.
97to2937 feedstocks
Removal of by mechanical
inorganic constituents of dewatering and leaching
biomass
Turn, S. Q. et al. Biomass and BioenerR), 1997. 12, (4), 241-252. The authors state that inorganic constituents of ash in biomass fuels are responsible for equipment failure and operating difficulties in thermochemical energy conversion facilities. Alkali metals, in the presence of chlorine and sulfur, are the leading contributors to this problem. Banagrass, a herbaceous species being considered for use as a dedicated energy crop, contains high levels of potassium and chlorine. Some inorganic elements are water soluble and the opportunity exists to remove them by mechanical dewatering and leaching as part of the feedstock preparation process. Laboratory-scale equipment, representative of processes employed in the commercial extraction of sugar from cane, was used to prepare banagrass fuel treatments. These included two degrees of comminution and two dewatering schemes. It is concluded that banagrass subjected to the most severe treatment, fine comminution with multi-step dewatering, should produce a boiler fuel with characteristics similar to those of baggasse.
Fuel and Energy Abstracts
July 1997
241