- Email: [email protected]
00524 Environmental consequences when growing short rotation forests in Sweden
07 Alternative energy sources (bioconversion energy) sulfur than coal, an increasing
biomass
share in the thermal output makes In addition, SOz can partly be captured in the ash by the alkaline-earth fractions of the biomass ash. As for sewage sludge, the emissions of SOz correlate with the sulfur content of the fuel and, hence, rise with an increasing share of this biomass. Due to the high volatile content of the biomass, low NO, emissions can be achieved both by air staging and by reburning. the SO2 emissions decrease proportionally.
Effect of insect 99KKl519 composltion of grain maize
culture
on
the
nutrient
Abasiekong, S. F. Bioresource Technology, 1998, 66, (1) 59-61. Testing the efficacy of storedgrain insects in increasing crude protein and other contents of raw and processed maize grain was aimed at in this study. Crude protein values increased with increasing culture duration and differed between the different maize substrates (raw kernels, cooked and dried kernels and coarsely broken raw kernels). Thus, raw maize particularly the coarsely broken type, seemed a preferred substrate where most insects produced highest amount of protein. Fat content of the insectrich biomass followed a pattern similar to that of protein, while soluble carbohydrate was reduced with increase in culture duration, possibly due to utilization by the insects.
Effect of peat ash fertilization on the nutrient status and biomass production of short-rotation willow on cutaway peatland area Hytonen, J. Biomassand Bioenergy, 1998, 15, (l), 83-92. 99100520
In a field experiment in central Finland recycling of peat ash back to cutaway peatland areas for growing short-rotation willows was studied. Application amounts of 10, 160, 320 and 640 t/ha were tested. Willow (S. x dasyclados) planted as cuttings was grown with one-year rotations for four years. The effect of additional fertilization (0, N, P, K, NP, NK, PK, NPK) was also tested. Biomass production. soil and foliar nutrient concentrations were measured. High ash application amounts increased the soil extractable P, K, Ca, Mg and Fe concentrations manyfold compared with the 10 t/ha treatment. Marked increases were also noted in soil pH, electrical conductivity and microbial activity. At the 10 t/ha treatment foliar K concentrations were low and higher applications of ash or additional K fertilization increased foliar K concentrations. The effect of potassium fertilization on foliar K concentrations decreased with increasing amounts of ash used. Biomass production was low at the 10 t/ha treatment and increased manyfoid with higher application amounts. However, additional potassium fertilization was necessary unless extremely high application amounts were used. Even the highest application amount of peat ash (640 tl ha) was not toxic to the willow.
Effect of surfactants and zeolites on simultaneous 99/99521 saccharification and fermentation of steam-exploded poplar biomass to ethanol Ballesteros, I. er al. Appl. Biochemical Biotechnol., 1998, 70-72, 369-381. Investigated has been the effect of the addition of different concentrations of Tween-80 and three different zeolite-like products on enzymic hydrolysis, ethanol fermentation, and simultaneous saccharification and fermentation (SSF) process. The ability of these products to enhance the effectiveness of the SSF process to ethanol of steam-exploded poplar biomass using the thermotolerant strain Kluyveromyces marxianus EMS-26 has been tested. Tween-80 increased enzymic hydrolysis yield by 20% when compared to results obtained in hydrolysis in absence of the additive. Zeolite-like products (ZESEP-56 and ZECER-56) improved rates of conversion and ethanol yields in the fermentation of liquid fraction recovered from steam-exploded poplar. The periods required for the completion of fermentation were approximately 10 h in the presence of zeolite-like products and 24 h in the absence of additives. The probable mode of action is through lowered levels of inhibitory substances because of adsorption by the additive.
Energy from municipal solid waste: a comparison 99100522 with coal combustion technology Ruth, L. R. Progress in Energy and Combustion Science, 1998, 24, (6), 545564. By converting municipal solid waste (MSW) to energy more valuable fuels can be conserved and the environment can be improved by lessening the amount of waste that must be landfilled and by conserving energy and natural resources. The importance of utilizing MSW was recognized in the 1991 US National Energy Strategy, which sought to ‘support the conversion of municipal solid waste to energy.’ One route to utilizing the energy value of MSW is to burn it in a steam power plant to generate electricity. Coal has long been the predominant source of energy for electricity production in the USA; therefore, a considerable science and technology base related to coal combustion and emissions control can be, and has been, applied with substantial benefit to MSW combustion. This paper compares the combustion of coal and MSW in terms of fuel characteristics, combustion technology, emissions, and ash utilization/disposal. Co-combustion of coal and MSW is also discussed. MSW issues that can be addressed by research and development are provided. The major environmental issues that designers of MSW combustion systems have had to address are emissions of trace organic compounds, particularly polychlorinated dioxins and furans, and trace elements such as mercury, lead, and cadmium. Emission of trace organics is generally the result of a poorly designed andior operated combustion system; modern MSW systems use good combustion practices
that destroy organic compounds during the combustion process. Proper control of air/fuel mixing and temperature, and avoidance of ‘quench’ zones in the furnace, help to ensure that potentially harinful organics are not emitted. Computer codes and other design and troubleshooting tools that were developed for coal combustion systems have been applied to improve the performance of waste-to-energy systems. Trace element emissions from both coal and MSW combustion results primarily from vaporization of elements during the combustion process. Most of the trace elements that are vaporized condense on fly ash as the combustion products cool downstream of the furnace and can be effectively controlled by using an efficient particulate removal device. However, volatile elements, particularly mercury, are emitted as a vapour. Several mechanisms are available to capture mercury vapour and some are in use. The development of satisfactory control technology for mercury is a topic currently of high interest in coal burning. The potential for leaching of trace elements and organics from MSW residues after disposal raises issues about the classification and management of ash. Results of laboratory leaching tests, especially for lead and cadmium, have not been consistently supported by field experience. Because of the large scale of coal-fired boilers for electricity production, co-firing of MSW with coal in such boilers could consume large.quantities of waste. Several short-term demonstrations have shown that co-firing is feasible. The issues involved in co-firing are emissions of trace elements, trace organics, and acid gases; boiler slagging and fouling; and long-term effects, such as corrosion and erosion of boiler tubes. Areas where research and development have contributed to improved MSW combustion include (a) the formation mechanisms of polychlorinated dioxins/furans, especially low-temperature, catalytic mechanisms, (b) methods of combustion air distribution in incinerators that result in better combustion and reduced emission of organic compounds. (c) the use of gas reburning to control the nature of mineral matter in coal determines its NOx and reduce emission of organic compounds. (d) practical methods for removing organic compounds and mercury from MSW flue gas, (e) the performance of electrostatic precipitators in removing MSW fly ash, particularly when co-firing MSW and coal in existing coal-fired boilers, and (f) burning MSW in fluidized beds or of pulverizing refuse-derived fuel and firing it in suspension-fired, pulverized coal boilers.
Enhancement of biodiversity in energy farming: 99100523 towards a functional approach
Londo, M. and Dekker, J. Making Bus. Biomass Energy, Environ., Chemical, Fibers Mater., Proc. Biomass Conf. Am. 3rd, 1997, (2), 15251532. Edited by Overend, R. P. and Chornet, E. Land use and the environment of agriculture will be affected when biomass is a substantial sustainable energy source, and special energy crops are grown on a large scale. Of these effects, biodiversity deserves special attention. The enhancement of biodiversity in energy farming via standard setting is the overall purpose of this project. In this study, the potential functionality of biodiversity in energy farming is proposed as a way of operationalizing the rather abstract and broad concept of biodiversity. Functions of biodiversity are reviewed, and examples of functions are worked out, based on the current literature on functions of nature in energy farming systems.
Environmental consequences when growing short rotation forests in Sweden Ledin, S. Biomass and Bioenergy, 1998, 15, (1). 49-55. 99100524
Short rotation forests with willows have an influence on the environment that differs from the influence of annual farm crops due to their being a perennial crop with good root penetration into the soil, high water use and efficient nutrient uptake over a long growing season. Also the landscape is affected differently by the dense willow stand, with a height of 7 m before harvest. There is usually less use of herbicides in the perennial woody crop. Due to larger amounts of litter from the willow plantation and no tillage, there is, with time, an increase of the humus content in the soil. In relation to this, the soil fauna, using organic material for food, prosper in the short rotation forest. Considerably more cadmium is taken up by the willows than by conventional annual crops. This could be used to clean the soil of cadmium, but more knowledge is needed for the optimization of this procedure. Willows are usually efficient in taking up nutrients, including nitrogen, but when used as vegetation filters it is important to assess the actual ability of a stand to take up nitrogen. This ability varies considerably with the developmental stage of the plantation and also with site conditions.
Environmental enhancement of U.S. biomass crop 9woo525 technologies: research results to date Tolbert, V. R. and Wright, L. L. Biomass and Bioenergv, 1998, 15, (l), 93100. Efforts by the USA to develop genetically superior short-rotation woody crops (hybrid poplar and willow) and herbaceous crops (switchgrass) are continuing. These biomass crops can provide multiple environmental benefits as well as energy and fibre. This paper focuses on results of sitespecific studies that are quantifying the environmental potential and ramifications of converting agricultural croplands to biomass crop production. At research-scales, no differences have been found in erosion and movement of nutrients from annual row crops switchgrass, and tree crops with and without a cover crop in the initial year of establishment. Research and watershed-scale studies on different soil types in different regions, and to match tree species with specific site characteristics and management
Fuel and Energy Absttncts
January 1999 51
biomass
share in the thermal output makes In addition, SOz can partly be captured in the ash by the alkaline-earth fractions of the biomass ash. As for sewage sludge, the emissions of SOz correlate with the sulfur content of the fuel and, hence, rise with an increasing share of this biomass. Due to the high volatile content of the biomass, low NO, emissions can be achieved both by air staging and by reburning. the SO2 emissions decrease proportionally.
Effect of insect 99KKl519 composltion of grain maize
culture
on
the
nutrient
Abasiekong, S. F. Bioresource Technology, 1998, 66, (1) 59-61. Testing the efficacy of storedgrain insects in increasing crude protein and other contents of raw and processed maize grain was aimed at in this study. Crude protein values increased with increasing culture duration and differed between the different maize substrates (raw kernels, cooked and dried kernels and coarsely broken raw kernels). Thus, raw maize particularly the coarsely broken type, seemed a preferred substrate where most insects produced highest amount of protein. Fat content of the insectrich biomass followed a pattern similar to that of protein, while soluble carbohydrate was reduced with increase in culture duration, possibly due to utilization by the insects.
Effect of peat ash fertilization on the nutrient status and biomass production of short-rotation willow on cutaway peatland area Hytonen, J. Biomassand Bioenergy, 1998, 15, (l), 83-92. 99100520
In a field experiment in central Finland recycling of peat ash back to cutaway peatland areas for growing short-rotation willows was studied. Application amounts of 10, 160, 320 and 640 t/ha were tested. Willow (S. x dasyclados) planted as cuttings was grown with one-year rotations for four years. The effect of additional fertilization (0, N, P, K, NP, NK, PK, NPK) was also tested. Biomass production. soil and foliar nutrient concentrations were measured. High ash application amounts increased the soil extractable P, K, Ca, Mg and Fe concentrations manyfold compared with the 10 t/ha treatment. Marked increases were also noted in soil pH, electrical conductivity and microbial activity. At the 10 t/ha treatment foliar K concentrations were low and higher applications of ash or additional K fertilization increased foliar K concentrations. The effect of potassium fertilization on foliar K concentrations decreased with increasing amounts of ash used. Biomass production was low at the 10 t/ha treatment and increased manyfoid with higher application amounts. However, additional potassium fertilization was necessary unless extremely high application amounts were used. Even the highest application amount of peat ash (640 tl ha) was not toxic to the willow.
Effect of surfactants and zeolites on simultaneous 99/99521 saccharification and fermentation of steam-exploded poplar biomass to ethanol Ballesteros, I. er al. Appl. Biochemical Biotechnol., 1998, 70-72, 369-381. Investigated has been the effect of the addition of different concentrations of Tween-80 and three different zeolite-like products on enzymic hydrolysis, ethanol fermentation, and simultaneous saccharification and fermentation (SSF) process. The ability of these products to enhance the effectiveness of the SSF process to ethanol of steam-exploded poplar biomass using the thermotolerant strain Kluyveromyces marxianus EMS-26 has been tested. Tween-80 increased enzymic hydrolysis yield by 20% when compared to results obtained in hydrolysis in absence of the additive. Zeolite-like products (ZESEP-56 and ZECER-56) improved rates of conversion and ethanol yields in the fermentation of liquid fraction recovered from steam-exploded poplar. The periods required for the completion of fermentation were approximately 10 h in the presence of zeolite-like products and 24 h in the absence of additives. The probable mode of action is through lowered levels of inhibitory substances because of adsorption by the additive.
Energy from municipal solid waste: a comparison 99100522 with coal combustion technology Ruth, L. R. Progress in Energy and Combustion Science, 1998, 24, (6), 545564. By converting municipal solid waste (MSW) to energy more valuable fuels can be conserved and the environment can be improved by lessening the amount of waste that must be landfilled and by conserving energy and natural resources. The importance of utilizing MSW was recognized in the 1991 US National Energy Strategy, which sought to ‘support the conversion of municipal solid waste to energy.’ One route to utilizing the energy value of MSW is to burn it in a steam power plant to generate electricity. Coal has long been the predominant source of energy for electricity production in the USA; therefore, a considerable science and technology base related to coal combustion and emissions control can be, and has been, applied with substantial benefit to MSW combustion. This paper compares the combustion of coal and MSW in terms of fuel characteristics, combustion technology, emissions, and ash utilization/disposal. Co-combustion of coal and MSW is also discussed. MSW issues that can be addressed by research and development are provided. The major environmental issues that designers of MSW combustion systems have had to address are emissions of trace organic compounds, particularly polychlorinated dioxins and furans, and trace elements such as mercury, lead, and cadmium. Emission of trace organics is generally the result of a poorly designed andior operated combustion system; modern MSW systems use good combustion practices
that destroy organic compounds during the combustion process. Proper control of air/fuel mixing and temperature, and avoidance of ‘quench’ zones in the furnace, help to ensure that potentially harinful organics are not emitted. Computer codes and other design and troubleshooting tools that were developed for coal combustion systems have been applied to improve the performance of waste-to-energy systems. Trace element emissions from both coal and MSW combustion results primarily from vaporization of elements during the combustion process. Most of the trace elements that are vaporized condense on fly ash as the combustion products cool downstream of the furnace and can be effectively controlled by using an efficient particulate removal device. However, volatile elements, particularly mercury, are emitted as a vapour. Several mechanisms are available to capture mercury vapour and some are in use. The development of satisfactory control technology for mercury is a topic currently of high interest in coal burning. The potential for leaching of trace elements and organics from MSW residues after disposal raises issues about the classification and management of ash. Results of laboratory leaching tests, especially for lead and cadmium, have not been consistently supported by field experience. Because of the large scale of coal-fired boilers for electricity production, co-firing of MSW with coal in such boilers could consume large.quantities of waste. Several short-term demonstrations have shown that co-firing is feasible. The issues involved in co-firing are emissions of trace elements, trace organics, and acid gases; boiler slagging and fouling; and long-term effects, such as corrosion and erosion of boiler tubes. Areas where research and development have contributed to improved MSW combustion include (a) the formation mechanisms of polychlorinated dioxins/furans, especially low-temperature, catalytic mechanisms, (b) methods of combustion air distribution in incinerators that result in better combustion and reduced emission of organic compounds. (c) the use of gas reburning to control the nature of mineral matter in coal determines its NOx and reduce emission of organic compounds. (d) practical methods for removing organic compounds and mercury from MSW flue gas, (e) the performance of electrostatic precipitators in removing MSW fly ash, particularly when co-firing MSW and coal in existing coal-fired boilers, and (f) burning MSW in fluidized beds or of pulverizing refuse-derived fuel and firing it in suspension-fired, pulverized coal boilers.
Enhancement of biodiversity in energy farming: 99100523 towards a functional approach
Londo, M. and Dekker, J. Making Bus. Biomass Energy, Environ., Chemical, Fibers Mater., Proc. Biomass Conf. Am. 3rd, 1997, (2), 15251532. Edited by Overend, R. P. and Chornet, E. Land use and the environment of agriculture will be affected when biomass is a substantial sustainable energy source, and special energy crops are grown on a large scale. Of these effects, biodiversity deserves special attention. The enhancement of biodiversity in energy farming via standard setting is the overall purpose of this project. In this study, the potential functionality of biodiversity in energy farming is proposed as a way of operationalizing the rather abstract and broad concept of biodiversity. Functions of biodiversity are reviewed, and examples of functions are worked out, based on the current literature on functions of nature in energy farming systems.
Environmental consequences when growing short rotation forests in Sweden Ledin, S. Biomass and Bioenergy, 1998, 15, (1). 49-55. 99100524
Short rotation forests with willows have an influence on the environment that differs from the influence of annual farm crops due to their being a perennial crop with good root penetration into the soil, high water use and efficient nutrient uptake over a long growing season. Also the landscape is affected differently by the dense willow stand, with a height of 7 m before harvest. There is usually less use of herbicides in the perennial woody crop. Due to larger amounts of litter from the willow plantation and no tillage, there is, with time, an increase of the humus content in the soil. In relation to this, the soil fauna, using organic material for food, prosper in the short rotation forest. Considerably more cadmium is taken up by the willows than by conventional annual crops. This could be used to clean the soil of cadmium, but more knowledge is needed for the optimization of this procedure. Willows are usually efficient in taking up nutrients, including nitrogen, but when used as vegetation filters it is important to assess the actual ability of a stand to take up nitrogen. This ability varies considerably with the developmental stage of the plantation and also with site conditions.
Environmental enhancement of U.S. biomass crop 9woo525 technologies: research results to date Tolbert, V. R. and Wright, L. L. Biomass and Bioenergv, 1998, 15, (l), 93100. Efforts by the USA to develop genetically superior short-rotation woody crops (hybrid poplar and willow) and herbaceous crops (switchgrass) are continuing. These biomass crops can provide multiple environmental benefits as well as energy and fibre. This paper focuses on results of sitespecific studies that are quantifying the environmental potential and ramifications of converting agricultural croplands to biomass crop production. At research-scales, no differences have been found in erosion and movement of nutrients from annual row crops switchgrass, and tree crops with and without a cover crop in the initial year of establishment. Research and watershed-scale studies on different soil types in different regions, and to match tree species with specific site characteristics and management
Fuel and Energy Absttncts
January 1999 51