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02711 Exergy analysis of a MSF distillation plant
11 Process heating, power and incineration (energy applications in industry) bed incinerator where a burning blend of three wastes (i.e. carbon soot, bio-sludge and fuel oil) is involved. To understand the mechanisms and related chemistry, several analytical approaches are employed to identify the bed materials (fresh sand and degrader sand) and the clinkers formed from full scale incinerator tests. The formation of clinker is believed to follow the mechanism of partial melting and/or reactive liquid sintering. The effects of temperature and blending ratio are tested in a muffle furnace. Carbon soot is believed to be more susceptible than the other two fuels. Thermodynamic multi-phase multi-component equilibrium calculations predict that the main low melting point species are predominant under the oxidizing condition, suggesting that reducing conditions might be favourable to restrain bed agglomeration. This study provides valuable information for better understanding of the chemistry related to clinker formation; it also helps in developing methods for control and possible elimination of the bed agglomeration problem for the design fuels.
05•02706 Changes in energy intensities of Thai industry between 1981 and 2000: a decomposition analysis Bhattacharyya, S. C, and Ussanarassamee, A. Energy Policy, 2005, 33, (8), 995-1002. Industrial demand accounts for about 30% of total final energy demand in Thailand, which experienced rapid increases in energy demand. This paper analyses the changes in industrial energy intensities over a period of 20 years (1981-2000) and identifies the factors affecting the energy consumption using logarithmic mean Divisia decomposition technique. It is found that Thai industry has passed through four different phases of growth and energy consumption has closely followed the industrial growth pattern. Energy intensity of Thai industry decreased from 17.6 toe/million babt (constant 1988 prices) in 1981 to 15.8 toe/million baht (1988 prices) in 2000. Nonmetallic mineral industry is the most intensive industry followed by basic metal, food and beverage, chemical and paper industries. The factor analysis indicates that both the structural effect and intensity effect contributed to a decline of aggregate intensity by 8% during 1981-1986 but in the rest of the periods, the two effects acted in opposite directions and thereby reducing the overall effect on aggregate intensity. Food and beverages, non-metallic mineral and chemical industries had significantly influenced the changes in aggregate intensity at sectoral level.
05/02707 Comparison of nickel- and iron-based oxygen carriers in chemical looping combustion for CO2 capture in power generation Wolf, J. et al. Fuel, 2005, 84, (7-8), 993 1006. In chemical looping combustion (CLC), a solid oxygen carrier circulates between two fluidized bed reactors and transports oxygen from the combustion air to the fuel; thus, the fuel is not mixed with air and an inherent CO2 separation occurs. In this paper, CLC is integrated in a natural gas fired combined cycle (NGCC). In this system, nickel-, and iron-based oxygen carriers are compared regarding the system's electrical and exergy efficiencies. Furthermore, the feasibility of CLC in two interconnected pressurized fluidized bed reactors (IPFBR) is studied for both oxygen carriers. The hypothetical layout plus dimensions of the IPFBR is presented for a capacity of 800 MW input of natural gas, Finally, top-firing is proposed as an option to overcome the apparent limitation in operating temperature of the reactor equipment and/or the oxygen carriers. The results indicate that there is no significant difference in the system's efficiency if both oxygen carriers could operate at the same temperature. However, CLC seems easier to be technically realized in an IPFBR with a nickel-based oxygen carrier.
05•02708 Development of a mixed integer programming model for technology development strategy and its application to IGCC technologies Akimoto, K. et al. Energy, 2005, 30, (7), 1176-1191. The cost effective R&D strategy is required especially for large-scale technologies because their development demands a large amount of investment in general. A mixed integer programming model was developed for the optimum technology development strategy in the field of energy systems. The module of the technology development process in the model is based on G E R T (graphical evaluation and review technique). In the module, a target technology is broken down into many elemental technologies. Usually several target technologies are involved for the evaluation of technology development strategy of one field and some of the elemental technologies are used common to a number of target technologies. Since elemental technologies are explicitly modelled, their spill-over effects are necessarily evaluated in this model analysis. The proposed method was applied to the evaluation of the development strategy of four types of IGCC (integrated coal gasification combined cycle) technologies which have different levels of thermal efficieneies. The total investment on both their R&D and practical use is optimized under the constraint of meeting a certain exogenous scenario of electricity demand. The
evaluation results include the optimum additional investment allocation among the developments of various elemental technologies; developments of integration technology for IGCC-43%, IGCC-55% and IGCC-48%, coal gasification technology, oxide dispersion strengthened super-alloy technology for the gas turbine blade and vane, ceramic matrix composite technology for the gas turbine blade, dry sulfur-removal technology, etc. are cost-effective.
05/02709 Economic evaluation of the industrial solar production of lime Gremaud, A. M. N. and Steinfeld, A. Energy Conversion and Management, 2005, 46, (6), 905-926. The use of concentrated solar energy in place of fossil fuels for driving the endothermic calcination reaction CaCO3 ~ CaO + CO2 at above 1300 K has the potential of reducing CO2 emissions by 20% in a stateof-the-art lime plant and up to 40% in a conventional cement plant. An economic assessment for an industrial solar calcination plant with 25 MWth solar input indicates that the cost of solar produced lime ranges between 128 and 157 S/t, about twice the current selling price of conventional lime. The solar production of high purity lime for special sectors in the chemical and pharmaceutical industry might be competitive with conventional fossil fuel based calcination processes at current fuel prices.
05/02710 Effect of fin pitch and number of tube rows on the air side performance of herringbone wavy fin and tube heat exchangers Wongwises, S. and Chokeman, Y. Energy Conversion and Management, 2005, 46, (13-14), 2216-2231. An experimental study is conducted to investigate the effects of a fin pitch and number of tube rows on the air side performance of fin and tube heat exchangers having herringbone wavy fin configuration at various fin thicknesses. A total of 10 samples of fin and tube heat exchanger with a tube outside diameter of 9.53 ram, transverse tube pitch of 25.4 m m and longitudinal tube pitch of 19.05 mm, having various fin pitches, number of tube rows and fin thicknesses, are tested in a well insulated open wind tunnel. The heat exchangers are made from aluminium plate finned, copper tube. Ambient air is used as a working fluid in the air side while hot water is used for the tube side. The results are presented as the variation of the Colburn factor and the friction factor with the Reynolds number based on the fin collar outside diameter (RED). The experimental results reveal that the fin pitch has an insignificant effect on the heat transfer characteristic. The friction factor increases with increasing fin pitch when ReD > 2500, approximately. The Colburn factor and the friction factor decrease with increasing number of tube rows when ReD < 4000, approximately. These results remain the same when the fin thickness is changed.
05/02711
Exergy analysis of a MSF distillation plant
Kahraman, N. and Cengel, Y. A. Energy Conversion and Management, 2005, 46, (15-16), 2625-2636. In this paper, a large MSF distillation plant in the gulf area is analysed thermodynamically using actual plant operation data. Exergy flow rates are evaluated throughout the plant, and the exergy flow diagram is prepared. The rates of exergy destruction and their percentages are indicated on the diagram so that the locations of highest exergy destruction can easily be identified. The highest exergy destruction (77.7%) occurs within the MSF unit, as expected, and this can be reduced by increasing the number of flashing stages. The exergy destruction in the pumps and motors account for 5.3% of the total, and this also can be reduced by using high efficiency motors and pumps. The plant is determined to have a second law efficiency of just 4.2%, which is very iow. This indicates that there are major opportunities in the plant to reduce exergy destruction and, thus, the amount of electric and thermal energy supplied, making the operation of the plant more cost effective.
05•02712 From physical properties of ice slurries to industrial ice slurry applications Egolf, P. W. and Kauffeld, M. International Journal of Refrigeration, 2005, 28, (1), 4-12. The use of ice slurries dates back many millennia, e,g. the ancient Romans applied the cooling of snow-water and ice-water mixtures. Approximately two decades ago a breakthrough of the new technology of producing ice slurries has set in the refrigeration domain for the cooling of shops and supermarkets. After some difficulties at the beginning, it is now possible to build systems, which operate as designed. However, there is still a huge potential to lower the energy consumption and the costs of the systems. Actions in this direction are the design of new ice slurry generators, the development of new concepts for storage and mixing, etc. In this article a short review of the basic research on ice slurries is presented. Furthermore, practical problems of the application of the technology in refrigeration and process techniques are discussed.
Fuel and Energy Abstracts November 2005 395
05•02706 Changes in energy intensities of Thai industry between 1981 and 2000: a decomposition analysis Bhattacharyya, S. C, and Ussanarassamee, A. Energy Policy, 2005, 33, (8), 995-1002. Industrial demand accounts for about 30% of total final energy demand in Thailand, which experienced rapid increases in energy demand. This paper analyses the changes in industrial energy intensities over a period of 20 years (1981-2000) and identifies the factors affecting the energy consumption using logarithmic mean Divisia decomposition technique. It is found that Thai industry has passed through four different phases of growth and energy consumption has closely followed the industrial growth pattern. Energy intensity of Thai industry decreased from 17.6 toe/million babt (constant 1988 prices) in 1981 to 15.8 toe/million baht (1988 prices) in 2000. Nonmetallic mineral industry is the most intensive industry followed by basic metal, food and beverage, chemical and paper industries. The factor analysis indicates that both the structural effect and intensity effect contributed to a decline of aggregate intensity by 8% during 1981-1986 but in the rest of the periods, the two effects acted in opposite directions and thereby reducing the overall effect on aggregate intensity. Food and beverages, non-metallic mineral and chemical industries had significantly influenced the changes in aggregate intensity at sectoral level.
05/02707 Comparison of nickel- and iron-based oxygen carriers in chemical looping combustion for CO2 capture in power generation Wolf, J. et al. Fuel, 2005, 84, (7-8), 993 1006. In chemical looping combustion (CLC), a solid oxygen carrier circulates between two fluidized bed reactors and transports oxygen from the combustion air to the fuel; thus, the fuel is not mixed with air and an inherent CO2 separation occurs. In this paper, CLC is integrated in a natural gas fired combined cycle (NGCC). In this system, nickel-, and iron-based oxygen carriers are compared regarding the system's electrical and exergy efficiencies. Furthermore, the feasibility of CLC in two interconnected pressurized fluidized bed reactors (IPFBR) is studied for both oxygen carriers. The hypothetical layout plus dimensions of the IPFBR is presented for a capacity of 800 MW input of natural gas, Finally, top-firing is proposed as an option to overcome the apparent limitation in operating temperature of the reactor equipment and/or the oxygen carriers. The results indicate that there is no significant difference in the system's efficiency if both oxygen carriers could operate at the same temperature. However, CLC seems easier to be technically realized in an IPFBR with a nickel-based oxygen carrier.
05•02708 Development of a mixed integer programming model for technology development strategy and its application to IGCC technologies Akimoto, K. et al. Energy, 2005, 30, (7), 1176-1191. The cost effective R&D strategy is required especially for large-scale technologies because their development demands a large amount of investment in general. A mixed integer programming model was developed for the optimum technology development strategy in the field of energy systems. The module of the technology development process in the model is based on G E R T (graphical evaluation and review technique). In the module, a target technology is broken down into many elemental technologies. Usually several target technologies are involved for the evaluation of technology development strategy of one field and some of the elemental technologies are used common to a number of target technologies. Since elemental technologies are explicitly modelled, their spill-over effects are necessarily evaluated in this model analysis. The proposed method was applied to the evaluation of the development strategy of four types of IGCC (integrated coal gasification combined cycle) technologies which have different levels of thermal efficieneies. The total investment on both their R&D and practical use is optimized under the constraint of meeting a certain exogenous scenario of electricity demand. The
evaluation results include the optimum additional investment allocation among the developments of various elemental technologies; developments of integration technology for IGCC-43%, IGCC-55% and IGCC-48%, coal gasification technology, oxide dispersion strengthened super-alloy technology for the gas turbine blade and vane, ceramic matrix composite technology for the gas turbine blade, dry sulfur-removal technology, etc. are cost-effective.
05/02709 Economic evaluation of the industrial solar production of lime Gremaud, A. M. N. and Steinfeld, A. Energy Conversion and Management, 2005, 46, (6), 905-926. The use of concentrated solar energy in place of fossil fuels for driving the endothermic calcination reaction CaCO3 ~ CaO + CO2 at above 1300 K has the potential of reducing CO2 emissions by 20% in a stateof-the-art lime plant and up to 40% in a conventional cement plant. An economic assessment for an industrial solar calcination plant with 25 MWth solar input indicates that the cost of solar produced lime ranges between 128 and 157 S/t, about twice the current selling price of conventional lime. The solar production of high purity lime for special sectors in the chemical and pharmaceutical industry might be competitive with conventional fossil fuel based calcination processes at current fuel prices.
05/02710 Effect of fin pitch and number of tube rows on the air side performance of herringbone wavy fin and tube heat exchangers Wongwises, S. and Chokeman, Y. Energy Conversion and Management, 2005, 46, (13-14), 2216-2231. An experimental study is conducted to investigate the effects of a fin pitch and number of tube rows on the air side performance of fin and tube heat exchangers having herringbone wavy fin configuration at various fin thicknesses. A total of 10 samples of fin and tube heat exchanger with a tube outside diameter of 9.53 ram, transverse tube pitch of 25.4 m m and longitudinal tube pitch of 19.05 mm, having various fin pitches, number of tube rows and fin thicknesses, are tested in a well insulated open wind tunnel. The heat exchangers are made from aluminium plate finned, copper tube. Ambient air is used as a working fluid in the air side while hot water is used for the tube side. The results are presented as the variation of the Colburn factor and the friction factor with the Reynolds number based on the fin collar outside diameter (RED). The experimental results reveal that the fin pitch has an insignificant effect on the heat transfer characteristic. The friction factor increases with increasing fin pitch when ReD > 2500, approximately. The Colburn factor and the friction factor decrease with increasing number of tube rows when ReD < 4000, approximately. These results remain the same when the fin thickness is changed.
05/02711
Exergy analysis of a MSF distillation plant
Kahraman, N. and Cengel, Y. A. Energy Conversion and Management, 2005, 46, (15-16), 2625-2636. In this paper, a large MSF distillation plant in the gulf area is analysed thermodynamically using actual plant operation data. Exergy flow rates are evaluated throughout the plant, and the exergy flow diagram is prepared. The rates of exergy destruction and their percentages are indicated on the diagram so that the locations of highest exergy destruction can easily be identified. The highest exergy destruction (77.7%) occurs within the MSF unit, as expected, and this can be reduced by increasing the number of flashing stages. The exergy destruction in the pumps and motors account for 5.3% of the total, and this also can be reduced by using high efficiency motors and pumps. The plant is determined to have a second law efficiency of just 4.2%, which is very iow. This indicates that there are major opportunities in the plant to reduce exergy destruction and, thus, the amount of electric and thermal energy supplied, making the operation of the plant more cost effective.
05•02712 From physical properties of ice slurries to industrial ice slurry applications Egolf, P. W. and Kauffeld, M. International Journal of Refrigeration, 2005, 28, (1), 4-12. The use of ice slurries dates back many millennia, e,g. the ancient Romans applied the cooling of snow-water and ice-water mixtures. Approximately two decades ago a breakthrough of the new technology of producing ice slurries has set in the refrigeration domain for the cooling of shops and supermarkets. After some difficulties at the beginning, it is now possible to build systems, which operate as designed. However, there is still a huge potential to lower the energy consumption and the costs of the systems. Actions in this direction are the design of new ice slurry generators, the development of new concepts for storage and mixing, etc. In this article a short review of the basic research on ice slurries is presented. Furthermore, practical problems of the application of the technology in refrigeration and process techniques are discussed.
Fuel and Energy Abstracts November 2005 395