- Email: [email protected]
The economic viability of commercial wind plants in Greece a complete sensitivity analysis
07 Alternative energy sources (wind energy) of aluminium pipes embedded over its surface. No glazing on the top of the cement collector solar collector or insulation at the back have been used as in conventional solar water heaters. Although concrete collectors without glazing at the top are less efficient they can provide moderate hot water to meet the various requirements of the building during the day. The cement concrete solar collectors have been tested for water heating for several years and the results are presented. This knowledge can be used by architects for designing the roof of the building which may serve as a low cost solar collector to provide hot water at moderate temperature in buildings for meeting various purposes during the daytime.
00100420 The development and testing of small concentrating PV systems Whitfield, G. R. et al. Solar Energy, 1999, 67, (l-3), 23-34. Spreadsheets have been used to compare some 90 possible small PV concentrator designs that might be suitable for use at remote sites. They have apertures of about 2 m2, use BP Solar LBG cells,_and employ small aperture modules to reduce heat sinking and construction costs. Designs include fixed V-troughs and CPCs, single axis tracked cylindrical lens and mirror systems, and two-axis tracked sphericalsymmetry systems. Performance and volume production costs were estimated. Four promising systems were constructed as prototypes: (A) Point-focus Fresnel lenses, two-axis tracking; Cg = 32 x and 69 x with secondaries. (B) Line-focus mirror parabolic troughs, one-axis tracking, Cg = 20x. (C) SMTS (‘single-mirror two-stage’), one-axis tracking, Cg = 30x. (F) Multiple line-focus mirror parabolic troughs, E-W I/day manual tracking, Cg = 6x. The prototypes were tested at Reading, and three for up to a year’s field trial at ZSw’s test site, Widderstall, in Germany. The best system efficiencies, normalized to 25°C and excluding the end losses of linear systems, were 12.5%, 13.2%, 13.6% and 14.3% for collectors A, B, C, and F, respectively. The collectors were practical and robust, and the performances of collectors B, C and F are only 10% below the estimates in the spreadsheet calculations. The best collectors have estimated production costs between 1.5 and 1.8 US%/Wp, yielding energy costs at a good site (excluding BOS and overheads) of between 5 and 7 cents/kWh (I8 and 25 cents/MJ). On the same cost basis a conventional PV array costs 4.3 %/Wp, and 18 cents/kWh (65 cents/MJ).
00100421 The TROF (tower reflector with optical fibers): a new degree of freedom for solar energy systems
Zik, 0. et al. Solar Energy, 1999, 67, (l-3), 13-22. The integration of optical fibres into solar energy systems requires a trade-off between the cost, attenuation, and a limited flux carrying capability (due to limited numerical aperture) on one hand, and the flexibility in light distribution on the other hand. This paper presents a novel approach that minimizes the length of fibres in the system while fully utilizing the flexibility advantage. Optical fibres have been steadily improving and their cost has been declining as a result of the proliferation of their use in communication, and more recently in the lighting industry. The use of fibres in concentrating solar thermal systems has potential advantages of providing unprecedented flexibility in the final concentration and the receiver design. A central receiver system based on the tower reflector with optical fibres (TROF) is presented as a case study in a comparison between conventional concepts of solar thermal power generation, and new concepts employing optical fibres. Two new approaches to thermal conversion utilizing the flexibility of a fibre-based system, non-isothermal hightemperature receivers and distributed receivers, are presented. An approximate performance and cost analysis that assumes massproduced solar-optimized fibres is presented. The effects of system size and several fibre types are discussed. The results show that the use of current optical fibres may become competitive for solar-driven electricity generation systems under optimistic assumptions. The analysis points to research and development directions that could lead to cost-effective TROF and other optical fibre-based systems in the future.
very high effectiveness. The corrected Q(r) values follow the respective actual data with very high accuracy even when the measured SR is decreased by factor 2-3 due to low shunt resistance of the solar cell.
Transient thermal analysis of a refractive secondary solar concentrator
00100423
Geng, S. M. and Macosko, R. P. Proc. Intersoc. Energy Comers. Eng. Con/., 1999, 34, 65&655. This paper describes a secondary concentrator, which is an optical device that accepts solar energy from a primary concentrator and directs and further intensifies the solar flux. The refractive secondary is a prime example of such a device, fabricated from an optically clear solid material that can transmit the solar energy efficiently by way of refraction and total internal reflection. When combined with a large state-of-the-art rigid or inflatable primary concentrator, the refractive secondary concentrator enables solar concentration ratios of 10000: 1. In support of potential space solar thermal power and propulsion applications, the NASA Glenn Research Centre is developing a singlecrystal refractive secondary concentrator for use at temperatures greater than 2000 K. Candidate optically clear single-crystal materials like sapphire and zirconia are being evaluated for this application. To support this evaluation, a three-dimensional transient thermal model of a refractive secondary concentrator in a typical solar thermal propulsion application was developed. The model along with the thermal predictions for both sapphire and zirconia prototypes are presented in this paper. These predictions are then used to establish parameters for analysing and testing the materials’ ability to survive stress and thermal shock. 00/00424 Transparent insulation material in solar system for candle production
Chaurasia, P. B. L. Energy Cowers. Manage., 2000, 41, (14), 15691584. A simple solar machine has been developed to melt paraffin wax for candle production. The present solar technology is a safe, convenient method of candle production and obviates any type of care or attendance during the wax melting process as required in old methods based on conventional fuels. It is quite useful in the cottage industry and generates employment. On the demand of professional candle makers, the solar candle machine has been further improved enabling manufacture of candles in the night as well. For it, transparent insulation material has been successfully tested over the absorbing surface in the solar machine, which was found to prolong the storage of molten wax for candle production after sunset. The present paper describes the complete solar technology for candle production, including the advantage of the improved model. 00100425 Use of PV systems in remote car filling stations Ahmad, G. E. and Mohamad, M. A. Energy Comers. Manage., 2000, 41, (l2), 1293-1301. In Egypt, the average daily solar energy incident on a horizontal surface exceeds 5 kWh/m’/day and also, there are many remote areas that are not covered by the electrical energy of the grid utility. So it was necessary to depend on solar energy in supplying these remote applications. This paper introduces a case study for designing a PV system for feeding a remote area car filling station to be operated using photovoltaic energy. The design parameters will depend mainly on the load energy needed by the station, the geographical site data (solar radiation, ambient temperature) and also, the degree of availability of electrical energy needed for the system. To ensure the PV system availability and reliability during its operation, an expectation for the system performance is prepared. The expected monthly average daily output energy from the PV system is compared with that needed by the load during a complete year. In the case of rural zones, it is proven that the economic situation of the photovoltaic system will be competitive, especially in a site of high availability of solar energy, like the remote areas of Egypt.
Wind energy
00100422 The use of the self-calibration method for accurate determination of silicon solar cell internal quantum efficiency
Bordin, N. et al. Sol. Energy Mat. & Sol. Cells , 2000, 63, (3), 247-257. The application of the self-calibration method as a means of increasing the accuracy of spectral response, SR, and internal quantum efficiency, Q(r), measurements is discussed. The principle of the method is the precise calculation of Q(r& of a test cell for light at ^(m-0.8 pm, where the response is weakly dependent on the emitter and base parameters. The ratio of the calculated and measured Q(r,,,) values gives the corresponding factor for shifting the experimental spectral response curve. The sequence of calculations is described, and an algorithm of the necessary operations for a computer is developed. Several examples of the use of the self-calibration method for correction of SR measurements of solar cells with low shunt resistance demonstrate its
44
Fuel and Energy Abstracts
January 2001
The economic viability of commercial wind plants in Greece a complete sensitivity analysis
00100426
Kaldellis, J. K. and Gavras, T. J. Energy Policy, 2000, 28, (S), 509-517. The influence of the governing techno-economic parameters on the economic behaviour of commercial wind parks is investigated. For this purpose, a complete cost-benefit analysis model, properly adapted for the Greek market, is developed in order to calculate the pay-back period and the economic efficiency of similar investments in the energy production sector. Moreover, the impact of various parameters - such as capital cost, return on investment index, local inflation rate index, electricity price escalation rate, installation capacity factor, M&O cost,
07 Alternative energy sources (others, including development, economics) turn-on key cost of the power plant, size of wind turbines used -on the economic viability and attractiveness is extensively investigated, using a well-elaborated simple ‘expert system’ type numerical code. Finally, the prediction results are summarized in a representative sensitivity analysis map, including the most reasonable economic scenarios. Taking into account the analytical results of the proposed study along with the existence of high wind potential regions in Greece, a remarkable growth of the wind energy sector is expected in the near future, leading to considerable investment profits and offering a strong position (share) of the liberalized local power market.
Others, including development, economics
W/O0427 A simple method for production of pure silica from rice hull ash
Kalapathy, U. et al. Bioresource Technology, 2000, 73, (3), 257-262. Rice hull ash (RI-IA), a waste product of the rice industry is rich in silica. A simple method based on alkaline extraction followed by acid precipitation was developed to produce pure silica xerogels from RHA, with minimal mineral contaminants. The silica gels produced were heated to 80°C for 12 hours to obtain xerogels. Silica and mineral contents of xerogels were determined by energy dispersive X-ray (EDX) and inductively-coupled plasma (ICP) emission spectrometers, respectively. Xerogels produced from RHA had 93% silica and 2.6% moisture. The major impurities of silica produced from RHA at an extraction yield of 91% were Na, K, and Ca. Acid washing prior to extraction resulted in silica with a lower concentration of Ca (~200 ppm). However, final water washing of the xerogel was more effective in producing silica with lower overall mineral content (Na ~200 ppm and K ~400 ppm). X-ray diffraction patterns revealed the amorphous nature of silica xerogel. Fourier transform infrared (FTIR) data indicated the presence of siloxane and silanol groups.
Biomass conversion to mixed alcohol fuels using the MixAlco process
00/00430
Holtzapple, M.T. er al. Appl. Biochem. Biotechnol., 1999, 77-79, 609631. The MixAlco process is a patented technology that converts any biodegradable material, including municipal solid waste, industrial biosludge, sewage sludge, manure, agricultural residues and energy crops into mixed alcohol fuels containing predominantly 2-propanol, but also higher alcohols up to 7-tridecanol. To increase the feedstock’s digestibility it is treated with lime. Then, it is fed into a fermentor in which a mixed culture of acid-forming micro-organisms produces carboxylic acids. Calcium carbonate is added to the fermentor to neutralize the acids to their corresponding carboxylate salt. The diluted (-3%) carboxylate salts are concentrated to 19% using an amine solvent that selectively extracts water. Multi-effect evaporators are used to complete the drying process. Finally, the dry salts are thermally converted to ketones, which are hydrogenated to alcohols. All the steps in the MixAlco process have been proven at the laboratory scale. This paper also provides a techno-economic model of the process.
00100421 Experimental investigation of paper mill sludge pyrolysis in the laboratory-scale rotary kiln
Li, s. et al. Gongcheng Rewuli Xuebao, 1999, 20, (3), 373-377. (In Chinese) From a point of view of pollution control and energy recovery, the pyrolysis which converts wastes to fuels and chemical products is a promising and practical alternative. This paper reports on the experimental study of the pyrolysis of paper mill sludge in the laboratory-scale, externally heated, rotary kiln. A discussion is also included on the correlation between the gas components and the temperature growth in addition to the heating value during pyrolysis. Meanwhile, the characteristics of semi-coke and the yields of gas, tar and semi-coke products varied with the pyrolysis final temperature A first-order apparent kinetic equation was successfully used to represent the gas release during the non-isothermal pyrolysis.
00/00432
Ignition behaviour of pulp and paper combustible
wastes
An analysis of alternative fuel credit provisions of US automotive fuel economy standards
00100428
Rubin, J. and Leiby, P. Energy Policy, 2000, 13, (9), 589-601. In the United States, alternative fuel vehicles are treated favourably in the calculations that are used to determine compliance with automotive fuel efficiency standards. It has been estimated that this favourable treatment is worth approximately $550-$1100 per alternative fuel vehicle in terms of avoided penalties. A dynamic simulation model must be used to examine the implications of this favourable treatment of alternative fuel vehicles for the goals of oil displacement contained in the United States Energy Policy Act. Welfare analysis demonstrates that the favourable treatment of alternative fuel vehicles costs $66 million or about 84 cents per gallon of gasoline displaced in the base case. Policy scenarios show greater costs. Whether this money is well spent depends on one’s views of the need to build alternative fuel and vehicle infrastructure and the goal of oil displacement.
Sun, C. L. and Kozinski, J. A. Fuel, 2000, 79, (13), 1587-1593. Ignition behaviour of combustible wastes from the pulp and paper industry was studied in a modified thermogravimetric furnace. Criteria for ignition and the ignition mechanism were developed. The ignition of combustible wastes was predominantly homogeneous. The influence of different factors, such as particle size, sample type, heating rate and oxygen concentratton, was studied. In general, no monotonic relationship between ignition temperature and particle size was observed. Different types of sample had different ignition temperatures (ranging from 203 to 227°C). The ignition temperature increased with heating rate but decreased with oxygen concentration. The combustible waste samples were collected and morphologically analysed at different stages of the heating process. No significant differences in morphology were observed just before and after ignition. The results obtained are useful in identifying the region for injection of combustible wastes into industrial combustors (e.g. boilers or fluidized beds).
Irreversible ecosystem change, species competition, and shifting cultivation 00100433
OO~Wu~2C~ An optimal renewable energy model for various _
Iniyan, S. and Sumathy, K. Energy, 2000, 25, (6), 563-575. Renewable energy sources are likely to play a significant role in meeting the future energy requirement of a developing country like India. The effect of introducing renewable energy sources on the commercial energy scene may have to be analysed carefully. In this paper, we present an optimal renewable energy model that minimizes the cost/efficiency ratio and determines the optimum allocation of different renewable energy sources for various end-uses. The potential of renewable energy sources, energy demand, reliability of renewable energy systems and their acceptance level will determine the pattern of renewable energy distribution and are used as constraints in the model. The model allocates the renewable energy distribution pattern for the year 2020-21 in India, which would be helpful for policy makers in commercializing the renewable energy sources to the greatest extent. The results indicate that solar energy systems can be utilized for lighting, pumping, heating and cooling to an extent of 6%, 16%, 2%, and 12% of total renewable energy demand in India, respectively. Similarly, the bio-energy systems can be utilized, 9% of lighting, 18% of cooking, 1% of pumping, 17% of heating and 14% of transportation of the total renewable energy demand. It is also observed that wind energy can be utilized for pumping end-use to an extent of 4% of total renewable energy demand. The scenario for different potential limits is presented in this paper. A sensitivity analysis has also been carried out to validate the model.
Albers, H. J. Goldbach, M. J. Resource and Energy Economics, 2000, 22, (3), 261-280. This paper explores the impact of resource use on species competition and the resulting effect on the regeneration of a renewable resource. In the case of shifting cultivation, agricultural activities alter the subsequent recovery of biomass during fallow upon which agricultural fertility depends. This paper introduces a model of agriculture’s impact on species competition and discontinuous ecological change, identifies conditions under which it is economically efficient to induce an ecological irreversibility, and compares these cases for farmers with and without land tenure security.
00100434 Method and apparatus for thermal decomposition-carbonization of combustible wastes by reduction Ishikawa, K. Jpn. Kokai Tokkyo Koho JP 11 293,254 [99 293,254] (Cl. ClOB53/00), 26 Ott 1999, Appl. 1998/130,945, 6 Apr 1998. 5. (In Japanese) The apparatus for the thermal decomposition-carbonization of combustible wastes using a reduction method, consists of a reduction chamber having a structure of an entrance door and an exit door for transporting and discharging the wastes. The reduction chamber is filled with nitrogen for carbonization under the oxygen-free state and because the two doors of the reduction chamber are not opened simultaneously, the flowing of outside atmosphere is prevented.
Fuel and Energy Abstracts
January 2001
45
00100420 The development and testing of small concentrating PV systems Whitfield, G. R. et al. Solar Energy, 1999, 67, (l-3), 23-34. Spreadsheets have been used to compare some 90 possible small PV concentrator designs that might be suitable for use at remote sites. They have apertures of about 2 m2, use BP Solar LBG cells,_and employ small aperture modules to reduce heat sinking and construction costs. Designs include fixed V-troughs and CPCs, single axis tracked cylindrical lens and mirror systems, and two-axis tracked sphericalsymmetry systems. Performance and volume production costs were estimated. Four promising systems were constructed as prototypes: (A) Point-focus Fresnel lenses, two-axis tracking; Cg = 32 x and 69 x with secondaries. (B) Line-focus mirror parabolic troughs, one-axis tracking, Cg = 20x. (C) SMTS (‘single-mirror two-stage’), one-axis tracking, Cg = 30x. (F) Multiple line-focus mirror parabolic troughs, E-W I/day manual tracking, Cg = 6x. The prototypes were tested at Reading, and three for up to a year’s field trial at ZSw’s test site, Widderstall, in Germany. The best system efficiencies, normalized to 25°C and excluding the end losses of linear systems, were 12.5%, 13.2%, 13.6% and 14.3% for collectors A, B, C, and F, respectively. The collectors were practical and robust, and the performances of collectors B, C and F are only 10% below the estimates in the spreadsheet calculations. The best collectors have estimated production costs between 1.5 and 1.8 US%/Wp, yielding energy costs at a good site (excluding BOS and overheads) of between 5 and 7 cents/kWh (I8 and 25 cents/MJ). On the same cost basis a conventional PV array costs 4.3 %/Wp, and 18 cents/kWh (65 cents/MJ).
00100421 The TROF (tower reflector with optical fibers): a new degree of freedom for solar energy systems
Zik, 0. et al. Solar Energy, 1999, 67, (l-3), 13-22. The integration of optical fibres into solar energy systems requires a trade-off between the cost, attenuation, and a limited flux carrying capability (due to limited numerical aperture) on one hand, and the flexibility in light distribution on the other hand. This paper presents a novel approach that minimizes the length of fibres in the system while fully utilizing the flexibility advantage. Optical fibres have been steadily improving and their cost has been declining as a result of the proliferation of their use in communication, and more recently in the lighting industry. The use of fibres in concentrating solar thermal systems has potential advantages of providing unprecedented flexibility in the final concentration and the receiver design. A central receiver system based on the tower reflector with optical fibres (TROF) is presented as a case study in a comparison between conventional concepts of solar thermal power generation, and new concepts employing optical fibres. Two new approaches to thermal conversion utilizing the flexibility of a fibre-based system, non-isothermal hightemperature receivers and distributed receivers, are presented. An approximate performance and cost analysis that assumes massproduced solar-optimized fibres is presented. The effects of system size and several fibre types are discussed. The results show that the use of current optical fibres may become competitive for solar-driven electricity generation systems under optimistic assumptions. The analysis points to research and development directions that could lead to cost-effective TROF and other optical fibre-based systems in the future.
very high effectiveness. The corrected Q(r) values follow the respective actual data with very high accuracy even when the measured SR is decreased by factor 2-3 due to low shunt resistance of the solar cell.
Transient thermal analysis of a refractive secondary solar concentrator
00100423
Geng, S. M. and Macosko, R. P. Proc. Intersoc. Energy Comers. Eng. Con/., 1999, 34, 65&655. This paper describes a secondary concentrator, which is an optical device that accepts solar energy from a primary concentrator and directs and further intensifies the solar flux. The refractive secondary is a prime example of such a device, fabricated from an optically clear solid material that can transmit the solar energy efficiently by way of refraction and total internal reflection. When combined with a large state-of-the-art rigid or inflatable primary concentrator, the refractive secondary concentrator enables solar concentration ratios of 10000: 1. In support of potential space solar thermal power and propulsion applications, the NASA Glenn Research Centre is developing a singlecrystal refractive secondary concentrator for use at temperatures greater than 2000 K. Candidate optically clear single-crystal materials like sapphire and zirconia are being evaluated for this application. To support this evaluation, a three-dimensional transient thermal model of a refractive secondary concentrator in a typical solar thermal propulsion application was developed. The model along with the thermal predictions for both sapphire and zirconia prototypes are presented in this paper. These predictions are then used to establish parameters for analysing and testing the materials’ ability to survive stress and thermal shock. 00/00424 Transparent insulation material in solar system for candle production
Chaurasia, P. B. L. Energy Cowers. Manage., 2000, 41, (14), 15691584. A simple solar machine has been developed to melt paraffin wax for candle production. The present solar technology is a safe, convenient method of candle production and obviates any type of care or attendance during the wax melting process as required in old methods based on conventional fuels. It is quite useful in the cottage industry and generates employment. On the demand of professional candle makers, the solar candle machine has been further improved enabling manufacture of candles in the night as well. For it, transparent insulation material has been successfully tested over the absorbing surface in the solar machine, which was found to prolong the storage of molten wax for candle production after sunset. The present paper describes the complete solar technology for candle production, including the advantage of the improved model. 00100425 Use of PV systems in remote car filling stations Ahmad, G. E. and Mohamad, M. A. Energy Comers. Manage., 2000, 41, (l2), 1293-1301. In Egypt, the average daily solar energy incident on a horizontal surface exceeds 5 kWh/m’/day and also, there are many remote areas that are not covered by the electrical energy of the grid utility. So it was necessary to depend on solar energy in supplying these remote applications. This paper introduces a case study for designing a PV system for feeding a remote area car filling station to be operated using photovoltaic energy. The design parameters will depend mainly on the load energy needed by the station, the geographical site data (solar radiation, ambient temperature) and also, the degree of availability of electrical energy needed for the system. To ensure the PV system availability and reliability during its operation, an expectation for the system performance is prepared. The expected monthly average daily output energy from the PV system is compared with that needed by the load during a complete year. In the case of rural zones, it is proven that the economic situation of the photovoltaic system will be competitive, especially in a site of high availability of solar energy, like the remote areas of Egypt.
Wind energy
00100422 The use of the self-calibration method for accurate determination of silicon solar cell internal quantum efficiency
Bordin, N. et al. Sol. Energy Mat. & Sol. Cells , 2000, 63, (3), 247-257. The application of the self-calibration method as a means of increasing the accuracy of spectral response, SR, and internal quantum efficiency, Q(r), measurements is discussed. The principle of the method is the precise calculation of Q(r& of a test cell for light at ^(m-0.8 pm, where the response is weakly dependent on the emitter and base parameters. The ratio of the calculated and measured Q(r,,,) values gives the corresponding factor for shifting the experimental spectral response curve. The sequence of calculations is described, and an algorithm of the necessary operations for a computer is developed. Several examples of the use of the self-calibration method for correction of SR measurements of solar cells with low shunt resistance demonstrate its
44
Fuel and Energy Abstracts
January 2001
The economic viability of commercial wind plants in Greece a complete sensitivity analysis
00100426
Kaldellis, J. K. and Gavras, T. J. Energy Policy, 2000, 28, (S), 509-517. The influence of the governing techno-economic parameters on the economic behaviour of commercial wind parks is investigated. For this purpose, a complete cost-benefit analysis model, properly adapted for the Greek market, is developed in order to calculate the pay-back period and the economic efficiency of similar investments in the energy production sector. Moreover, the impact of various parameters - such as capital cost, return on investment index, local inflation rate index, electricity price escalation rate, installation capacity factor, M&O cost,
07 Alternative energy sources (others, including development, economics) turn-on key cost of the power plant, size of wind turbines used -on the economic viability and attractiveness is extensively investigated, using a well-elaborated simple ‘expert system’ type numerical code. Finally, the prediction results are summarized in a representative sensitivity analysis map, including the most reasonable economic scenarios. Taking into account the analytical results of the proposed study along with the existence of high wind potential regions in Greece, a remarkable growth of the wind energy sector is expected in the near future, leading to considerable investment profits and offering a strong position (share) of the liberalized local power market.
Others, including development, economics
W/O0427 A simple method for production of pure silica from rice hull ash
Kalapathy, U. et al. Bioresource Technology, 2000, 73, (3), 257-262. Rice hull ash (RI-IA), a waste product of the rice industry is rich in silica. A simple method based on alkaline extraction followed by acid precipitation was developed to produce pure silica xerogels from RHA, with minimal mineral contaminants. The silica gels produced were heated to 80°C for 12 hours to obtain xerogels. Silica and mineral contents of xerogels were determined by energy dispersive X-ray (EDX) and inductively-coupled plasma (ICP) emission spectrometers, respectively. Xerogels produced from RHA had 93% silica and 2.6% moisture. The major impurities of silica produced from RHA at an extraction yield of 91% were Na, K, and Ca. Acid washing prior to extraction resulted in silica with a lower concentration of Ca (~200 ppm). However, final water washing of the xerogel was more effective in producing silica with lower overall mineral content (Na ~200 ppm and K ~400 ppm). X-ray diffraction patterns revealed the amorphous nature of silica xerogel. Fourier transform infrared (FTIR) data indicated the presence of siloxane and silanol groups.
Biomass conversion to mixed alcohol fuels using the MixAlco process
00/00430
Holtzapple, M.T. er al. Appl. Biochem. Biotechnol., 1999, 77-79, 609631. The MixAlco process is a patented technology that converts any biodegradable material, including municipal solid waste, industrial biosludge, sewage sludge, manure, agricultural residues and energy crops into mixed alcohol fuels containing predominantly 2-propanol, but also higher alcohols up to 7-tridecanol. To increase the feedstock’s digestibility it is treated with lime. Then, it is fed into a fermentor in which a mixed culture of acid-forming micro-organisms produces carboxylic acids. Calcium carbonate is added to the fermentor to neutralize the acids to their corresponding carboxylate salt. The diluted (-3%) carboxylate salts are concentrated to 19% using an amine solvent that selectively extracts water. Multi-effect evaporators are used to complete the drying process. Finally, the dry salts are thermally converted to ketones, which are hydrogenated to alcohols. All the steps in the MixAlco process have been proven at the laboratory scale. This paper also provides a techno-economic model of the process.
00100421 Experimental investigation of paper mill sludge pyrolysis in the laboratory-scale rotary kiln
Li, s. et al. Gongcheng Rewuli Xuebao, 1999, 20, (3), 373-377. (In Chinese) From a point of view of pollution control and energy recovery, the pyrolysis which converts wastes to fuels and chemical products is a promising and practical alternative. This paper reports on the experimental study of the pyrolysis of paper mill sludge in the laboratory-scale, externally heated, rotary kiln. A discussion is also included on the correlation between the gas components and the temperature growth in addition to the heating value during pyrolysis. Meanwhile, the characteristics of semi-coke and the yields of gas, tar and semi-coke products varied with the pyrolysis final temperature A first-order apparent kinetic equation was successfully used to represent the gas release during the non-isothermal pyrolysis.
00/00432
Ignition behaviour of pulp and paper combustible
wastes
An analysis of alternative fuel credit provisions of US automotive fuel economy standards
00100428
Rubin, J. and Leiby, P. Energy Policy, 2000, 13, (9), 589-601. In the United States, alternative fuel vehicles are treated favourably in the calculations that are used to determine compliance with automotive fuel efficiency standards. It has been estimated that this favourable treatment is worth approximately $550-$1100 per alternative fuel vehicle in terms of avoided penalties. A dynamic simulation model must be used to examine the implications of this favourable treatment of alternative fuel vehicles for the goals of oil displacement contained in the United States Energy Policy Act. Welfare analysis demonstrates that the favourable treatment of alternative fuel vehicles costs $66 million or about 84 cents per gallon of gasoline displaced in the base case. Policy scenarios show greater costs. Whether this money is well spent depends on one’s views of the need to build alternative fuel and vehicle infrastructure and the goal of oil displacement.
Sun, C. L. and Kozinski, J. A. Fuel, 2000, 79, (13), 1587-1593. Ignition behaviour of combustible wastes from the pulp and paper industry was studied in a modified thermogravimetric furnace. Criteria for ignition and the ignition mechanism were developed. The ignition of combustible wastes was predominantly homogeneous. The influence of different factors, such as particle size, sample type, heating rate and oxygen concentratton, was studied. In general, no monotonic relationship between ignition temperature and particle size was observed. Different types of sample had different ignition temperatures (ranging from 203 to 227°C). The ignition temperature increased with heating rate but decreased with oxygen concentration. The combustible waste samples were collected and morphologically analysed at different stages of the heating process. No significant differences in morphology were observed just before and after ignition. The results obtained are useful in identifying the region for injection of combustible wastes into industrial combustors (e.g. boilers or fluidized beds).
Irreversible ecosystem change, species competition, and shifting cultivation 00100433
OO~Wu~2C~ An optimal renewable energy model for various _
Iniyan, S. and Sumathy, K. Energy, 2000, 25, (6), 563-575. Renewable energy sources are likely to play a significant role in meeting the future energy requirement of a developing country like India. The effect of introducing renewable energy sources on the commercial energy scene may have to be analysed carefully. In this paper, we present an optimal renewable energy model that minimizes the cost/efficiency ratio and determines the optimum allocation of different renewable energy sources for various end-uses. The potential of renewable energy sources, energy demand, reliability of renewable energy systems and their acceptance level will determine the pattern of renewable energy distribution and are used as constraints in the model. The model allocates the renewable energy distribution pattern for the year 2020-21 in India, which would be helpful for policy makers in commercializing the renewable energy sources to the greatest extent. The results indicate that solar energy systems can be utilized for lighting, pumping, heating and cooling to an extent of 6%, 16%, 2%, and 12% of total renewable energy demand in India, respectively. Similarly, the bio-energy systems can be utilized, 9% of lighting, 18% of cooking, 1% of pumping, 17% of heating and 14% of transportation of the total renewable energy demand. It is also observed that wind energy can be utilized for pumping end-use to an extent of 4% of total renewable energy demand. The scenario for different potential limits is presented in this paper. A sensitivity analysis has also been carried out to validate the model.
Albers, H. J. Goldbach, M. J. Resource and Energy Economics, 2000, 22, (3), 261-280. This paper explores the impact of resource use on species competition and the resulting effect on the regeneration of a renewable resource. In the case of shifting cultivation, agricultural activities alter the subsequent recovery of biomass during fallow upon which agricultural fertility depends. This paper introduces a model of agriculture’s impact on species competition and discontinuous ecological change, identifies conditions under which it is economically efficient to induce an ecological irreversibility, and compares these cases for farmers with and without land tenure security.
00100434 Method and apparatus for thermal decomposition-carbonization of combustible wastes by reduction Ishikawa, K. Jpn. Kokai Tokkyo Koho JP 11 293,254 [99 293,254] (Cl. ClOB53/00), 26 Ott 1999, Appl. 1998/130,945, 6 Apr 1998. 5. (In Japanese) The apparatus for the thermal decomposition-carbonization of combustible wastes using a reduction method, consists of a reduction chamber having a structure of an entrance door and an exit door for transporting and discharging the wastes. The reduction chamber is filled with nitrogen for carbonization under the oxygen-free state and because the two doors of the reduction chamber are not opened simultaneously, the flowing of outside atmosphere is prevented.
Fuel and Energy Abstracts
January 2001
45