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Circulating fluid bed gasifier for biomass. THERMIE demonstration project in Lahti, Finland
07 Alternative energy sources (bioconversionenergy) than those in case of fossil fuels. Therefore, research and development is carried out for the application of renewables now and in the near future. This chapter focuses on biomass applications and more specifically on the use of catalysts for the conversion technologies of biomass. Promising technologies, which are in a demonstration phase, are gasification, pyrolysis and hydrothermal upgrading. The products from these types of conversion technologies are: gas, fuel oil or bio-oil transport fuels and chemicals for the food and chemical industry. Of most bio-oil upgrading research, the production of hydrocarbons is the major objective. Flash and fast pyrolysis are techniques combining high heating rates and short reaction times. Valuable products are preserved with rapid quenching. Most of the technologies are studied on laboratory-scale or pilot-scale. For a number of conversion routes, catalysts are applied. During the upgrading of pyrolysis oils, char formation and coke deposition are the major problems. Coke deposition deactivates the catalyst and has to be avoided or minimized. Pyrolysis oils are highly oxygenated, corrosive, viscous, relatively unstable and very complex. However, catalytic upgrading may produce a high valuable chemical feedstock. Oxygen in the oxygenated compounds is, therefore, converted to CO and CO? rather than HsO to preserve hydrogen for hydrocarbon reactions. Finally, this paper also discusses the use of catalysts in the field of thermal conversion of biomass. W/O0358 Circulating fluid bed gasifier for biomass. THERMIE demonstration project in Lahti, Finland Nieminen, J. et al. VGB Krafiverksrech, 1999, 79, (IO), 13&135. (In German) The development of the advanced Foster Wheeler Energia Oy’s Circulating Fluidized Bed combustion system was so successful that it subsequently led to the development of the CFB gasification technology in the early 1980s. The dramatical increase in oil price during the oil crisis was the driving force for the developing work. The primary advantage of CFB gasification technology is that it enables the replacement of expensive fuels such as oil or gas by cheap solid fuels. Prior to this Lahti project Foster Wheeler Energia Oy has supplied four commercial scale CFB gasifiers during the mid-1980s to the pulp and paper industry with capacities from 17 to 35 MW based on fuel input. Waste wood is used as the feedstock in these applications and the units are still operating successfully today.
CWOfJ359 Conversion of biomass using glycerin to liquid fuel for blending gasoline as alternative engine fuel Demirbas, A. Energy Convers. Manage., 2000, 41, (15), 1741-1748. Dried ground biomass samples, being heated for 20 minutes in anhydrous glycerin in the presence of NasCOs or KOH, have been converted completely into water insoluble and soluble chemicals. The most important variables appear to be temperature, amount of alkali and the nominal reaction time among the reaction parameters. The yield of total water insolubles is 68.4% from the beech wood in the presence of sodium carbonate. At these conditions, the yield of gaseous products is almost negligible. The acetone solubles from acidification of the liquefaction products was called biofuel in this study. The solubilitv of the biofuel in gasoline was tested as 1.96% bv weieht. When lb% ethanol is added-to gasoline, the octane number incre&ed by 8%. The Cs, Cd and C.&o and n-alcohols were found to be the most effective blending agents in reducing the phase separation temperature. 00100380
Effect of lignin content on aqueous liquefaction products of biomass
Demirbas, A. Energy Convers. Manage., 2000, 41, (15), 1601-1607. Nine species of biomass with different lignin contents were liquefied by water in an autoclave at non-catalytic and catalytic runs. The absolute values of the correlation coefficients between the lignin content and the oil and the char yields were about 0.898 for non- catalytic aqueous liauefaction and 0.883 for catalvtic aaueous liauefaction. indicatine a stiong correletion. With both processes of aqueous liquefaction, with increasing lignin content, the oil yield decreased and the char yield increased.
W/O0381 Feasibility study of energy use for densificated lignocellulosic material (briquettes)
Tabarks, J. L. M. er al. Fuel,2000, 79, (IO), 122991237. This article’presents a study on a series of briquettes made from forest or industrial waste, some types of which have not to date been used in briquette formation. They are evaluated from both an energy and economic viewpoint. Lignocellulosic densification improves the briquettes’ behaviour as a fuel by increasing the homogeneity and by being easier to manage and transport. Lignocellulosic binderless briquettes’ characteristic net heating value (LHV) and remaining amount of fuel during combustion (weight) have been investigated to obtain a general expression function of production and raw material factors. In both cases the main factor is the fixed carbon in a quadratic way as all the factors are easily measurable.
00100382
Gas cleaning for IC engine applications from fixed bed biomass gasification Hasler, P. Nussbaumer, T. Biomass Bioenergy, 1999, 16, (6), 385-395. Gas cleaning for tar and particle removal is necessary for internal combustion (IC) engine applications of producer gas from fixed bed biomass gasifiers which are usually in the capacity range from 100 kW up to 5000 kW. In the present investigation, tar and particle collection efficiencies have been determined in a wash tower, a sand bed filter, two different fabric filters and a rotational particle separator in different test runs with fixed bed gasifiers. A fixed bed batch reactor, was used to investigate tar adsorption on coke. Furthermore, data from literature for catalytic tar crackers, venturi scrubbers, a rotational atomizer and a wet electrostatic precipitator (ESP) are given. Based on the presented gas cleaning efficiencies and the investment cost, an assessment of gas cleaning systems is made for IC engine applications from cocurrent gasifiers. The postulated gas quality requirements for IC engines cannot be safely achieved with state-of-the-art gas cleaning techniques and that 90% particle removal is easier to achieve than 90% tar removal. Except for the catalytic tar crackers which are considered as an option for applications above several MW and for gases with a high tar level, none of the investigated gas cleaning systems can securely meet a tar reduction exceeding 90%. Therefore one of the kev issues for successfully applying biomass derived producer gas from small scale gasifiers is the removal of tar, where it is required to be developed further. 00100383
Gasification and combustion of biomass in
Denmark Zysin, L. V. Koshkin, N. L. Teploener-getika (Moscow), 1999, 2, 73-75. (In Russian) A discussion of the use of biomass in Denmark. A description is also provided of the design of a commercial power plant operating on various forms of wood waste and coal. 00100384 Gasification of biomass chars in air - effect of heat treatment temperature Devi, T. G. and Kannan, M. P. Energy Fuels, 2000, 14, (l), 127-130. Three biomass materials-coir dust (CD), wheat straw (WS), and potato pulp (PP)-were pyrolysed under nitrogen, and the resultant chars were gasified in air at 400°C. In all cases, gasification rate of the chars showed the normal dependence on heat treatment temperature (HIT), i.e.. a decrease with increasine HIT. onlv UD to a certain value of H’IT (560, 550, and 750 “C for CD: WS, and PP,’ respectively), above which the rate dramatically increases. This contrasts with the monotonic decrease in reactivity reported for coal chars. It is believed that the unusual H’IT effect is a result of a change in the chemical state of the indigenous potassium species at the H’IT inflection temperature. 00/00385
Kinetics of ammonia decomposition in hot gas
cleaning Wang, W. et al. Ind. Eng. Chem. Res., 1999, 38, (11) 4175-4182. A study on the reduction in the ammonia content in fuel gas produced by biomass gasification. The experiments were performed in a fiiedbed reactor at 200-1000”, 21 atm. A kinetic model for ammonia decomposition was developed. The partial pressure of hydrogen in the fuel eas was a kev factor to model ammonia decomuosition. Activation . energies in the empty reactor, on carbon, and in a sand bed were similar, 130-140 kJ/mol. The frequency factors for carbon and sand were ten times as large as for the empty reactor. The activation energy for a nickel-based catalvst was 111-113 kJ/mol. The nickel-based catalyst was deactivated by the carbon deposit. It was discovered that to avoid carbon fouling and achieve high ammonia removal efficiency, it was essential to use high temperatures. Estimations of the ammonia reduction for fuel gas showed that a moderate amount of ammonia could be removed by use of the nickel-based pellets at 800”. 00100388 Lignin -the raw material for industry in the future Zuman, P. and Rupp, E. Biomass, Proc. Biomass Co& Am.,, 1999, 1, 555-562. Edited by Overend R.P. and Chornet E. When petroleum and coal reserves are finally exhausted, lignin has a promising future as a raw material for synthesizing aromatic organic compounds. Economic cleavage of lignin under mild conditions (pH 812, 25”) was demonstrated. Cleavage follows first-order kinetics and rate constants (k’) increase with increasine DH. The nlot s of k’ = f(oH) -\r--, -.s indicates the presence of a rapidly estabhshed acid-base equilibrium with pK. z 11. Phenolate formation is considered to precede the unzipping of the polymer. The only step that can be excluded is the rate determining addition of OH’- ions. Natural (rot wood) lignin and kraft lignin demonstrate similar cleavage patterns; which suggests they have similar cross-linking.
Possibility of renewable energy production and CO, mitigation by thermochemical liquefaction of microalgae
00100387
Sawayama,
S. et al. Biomass Bioenergy,
1999, 17, (1) 33-39.
Fuel and Energy Abstracts
January 2001
37
CWOfJ359 Conversion of biomass using glycerin to liquid fuel for blending gasoline as alternative engine fuel Demirbas, A. Energy Convers. Manage., 2000, 41, (15), 1741-1748. Dried ground biomass samples, being heated for 20 minutes in anhydrous glycerin in the presence of NasCOs or KOH, have been converted completely into water insoluble and soluble chemicals. The most important variables appear to be temperature, amount of alkali and the nominal reaction time among the reaction parameters. The yield of total water insolubles is 68.4% from the beech wood in the presence of sodium carbonate. At these conditions, the yield of gaseous products is almost negligible. The acetone solubles from acidification of the liquefaction products was called biofuel in this study. The solubilitv of the biofuel in gasoline was tested as 1.96% bv weieht. When lb% ethanol is added-to gasoline, the octane number incre&ed by 8%. The Cs, Cd and C.&o and n-alcohols were found to be the most effective blending agents in reducing the phase separation temperature. 00100380
Effect of lignin content on aqueous liquefaction products of biomass
Demirbas, A. Energy Convers. Manage., 2000, 41, (15), 1601-1607. Nine species of biomass with different lignin contents were liquefied by water in an autoclave at non-catalytic and catalytic runs. The absolute values of the correlation coefficients between the lignin content and the oil and the char yields were about 0.898 for non- catalytic aqueous liauefaction and 0.883 for catalvtic aaueous liauefaction. indicatine a stiong correletion. With both processes of aqueous liquefaction, with increasing lignin content, the oil yield decreased and the char yield increased.
W/O0381 Feasibility study of energy use for densificated lignocellulosic material (briquettes)
Tabarks, J. L. M. er al. Fuel,2000, 79, (IO), 122991237. This article’presents a study on a series of briquettes made from forest or industrial waste, some types of which have not to date been used in briquette formation. They are evaluated from both an energy and economic viewpoint. Lignocellulosic densification improves the briquettes’ behaviour as a fuel by increasing the homogeneity and by being easier to manage and transport. Lignocellulosic binderless briquettes’ characteristic net heating value (LHV) and remaining amount of fuel during combustion (weight) have been investigated to obtain a general expression function of production and raw material factors. In both cases the main factor is the fixed carbon in a quadratic way as all the factors are easily measurable.
00100382
Gas cleaning for IC engine applications from fixed bed biomass gasification Hasler, P. Nussbaumer, T. Biomass Bioenergy, 1999, 16, (6), 385-395. Gas cleaning for tar and particle removal is necessary for internal combustion (IC) engine applications of producer gas from fixed bed biomass gasifiers which are usually in the capacity range from 100 kW up to 5000 kW. In the present investigation, tar and particle collection efficiencies have been determined in a wash tower, a sand bed filter, two different fabric filters and a rotational particle separator in different test runs with fixed bed gasifiers. A fixed bed batch reactor, was used to investigate tar adsorption on coke. Furthermore, data from literature for catalytic tar crackers, venturi scrubbers, a rotational atomizer and a wet electrostatic precipitator (ESP) are given. Based on the presented gas cleaning efficiencies and the investment cost, an assessment of gas cleaning systems is made for IC engine applications from cocurrent gasifiers. The postulated gas quality requirements for IC engines cannot be safely achieved with state-of-the-art gas cleaning techniques and that 90% particle removal is easier to achieve than 90% tar removal. Except for the catalytic tar crackers which are considered as an option for applications above several MW and for gases with a high tar level, none of the investigated gas cleaning systems can securely meet a tar reduction exceeding 90%. Therefore one of the kev issues for successfully applying biomass derived producer gas from small scale gasifiers is the removal of tar, where it is required to be developed further. 00100383
Gasification and combustion of biomass in
Denmark Zysin, L. V. Koshkin, N. L. Teploener-getika (Moscow), 1999, 2, 73-75. (In Russian) A discussion of the use of biomass in Denmark. A description is also provided of the design of a commercial power plant operating on various forms of wood waste and coal. 00100384 Gasification of biomass chars in air - effect of heat treatment temperature Devi, T. G. and Kannan, M. P. Energy Fuels, 2000, 14, (l), 127-130. Three biomass materials-coir dust (CD), wheat straw (WS), and potato pulp (PP)-were pyrolysed under nitrogen, and the resultant chars were gasified in air at 400°C. In all cases, gasification rate of the chars showed the normal dependence on heat treatment temperature (HIT), i.e.. a decrease with increasine HIT. onlv UD to a certain value of H’IT (560, 550, and 750 “C for CD: WS, and PP,’ respectively), above which the rate dramatically increases. This contrasts with the monotonic decrease in reactivity reported for coal chars. It is believed that the unusual H’IT effect is a result of a change in the chemical state of the indigenous potassium species at the H’IT inflection temperature. 00/00385
Kinetics of ammonia decomposition in hot gas
cleaning Wang, W. et al. Ind. Eng. Chem. Res., 1999, 38, (11) 4175-4182. A study on the reduction in the ammonia content in fuel gas produced by biomass gasification. The experiments were performed in a fiiedbed reactor at 200-1000”, 21 atm. A kinetic model for ammonia decomposition was developed. The partial pressure of hydrogen in the fuel eas was a kev factor to model ammonia decomuosition. Activation . energies in the empty reactor, on carbon, and in a sand bed were similar, 130-140 kJ/mol. The frequency factors for carbon and sand were ten times as large as for the empty reactor. The activation energy for a nickel-based catalvst was 111-113 kJ/mol. The nickel-based catalyst was deactivated by the carbon deposit. It was discovered that to avoid carbon fouling and achieve high ammonia removal efficiency, it was essential to use high temperatures. Estimations of the ammonia reduction for fuel gas showed that a moderate amount of ammonia could be removed by use of the nickel-based pellets at 800”. 00100388 Lignin -the raw material for industry in the future Zuman, P. and Rupp, E. Biomass, Proc. Biomass Co& Am.,, 1999, 1, 555-562. Edited by Overend R.P. and Chornet E. When petroleum and coal reserves are finally exhausted, lignin has a promising future as a raw material for synthesizing aromatic organic compounds. Economic cleavage of lignin under mild conditions (pH 812, 25”) was demonstrated. Cleavage follows first-order kinetics and rate constants (k’) increase with increasine DH. The nlot s of k’ = f(oH) -\r--, -.s indicates the presence of a rapidly estabhshed acid-base equilibrium with pK. z 11. Phenolate formation is considered to precede the unzipping of the polymer. The only step that can be excluded is the rate determining addition of OH’- ions. Natural (rot wood) lignin and kraft lignin demonstrate similar cleavage patterns; which suggests they have similar cross-linking.
Possibility of renewable energy production and CO, mitigation by thermochemical liquefaction of microalgae
00100387
Sawayama,
S. et al. Biomass Bioenergy,
1999, 17, (1) 33-39.
Fuel and Energy Abstracts
January 2001
37