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00491 Dust removal and desulfurization of flue gas from small-medium type coal-burning boiler
08
Steam raising (boiler operation/design)
Premium power comes from renewable 98100484 fuel at all Jones. C. Power, 1997, 141. (S), 2%30, 32.
fuel-or
no
Strategies for a nation-wide survey of renewable98100485 enerav resources available in each villaae in India Arian%a, A. and Chowhan, P. L. Proc. In&c. Energy Comers. Eng. Conf., 1997. 32, 2181-2186. In India, about 0.6 million villages spread over the length and breadth of the country offer various economic opportunities for judicious exploitation of local resources, holding the key to sustainable development. Energy is the crucial input for sustainable development of the rural areas in the long run and the demand for energy is likely to continue to rise due to the development process and increase in population. Efficient use of non commercial fuels is important, while renewable sources of energy such as sun, wind and hydro potential have to be harnessed simultaneously. The electricity needs of the villages are by and large taken care of by SEBs under the REC schemes. However, there is need for survey of village-wise energy resources from the planning viewpoint, so that least cost energy options could be exercised as between conventional and renewable sources of energy. As data availability is poor, proper statistical analysis is needed to ascertain the load potential and demand in the villages and appropriate system arrangements. The census data 1991 contains valuable information about the villages. However, more details are required to be gathered in the ensuing Census 2001, so that energy plans may be drawn up village-wise/ block-wise/district-wise in a systematic manner based on updated national data. This paper discusses the various strategies required for adoption for a nation-wide survey including classification, selection criteria, division of work, questionnaire and action plan systematically compile the data to prepare a master plan for the use of non-conventional energy sources. Use of experience curves to analyse the prospects 98100488 for diffusion and adoption of renewable energy technology Neij, L. Energy Policy, 1997, 23 The prospects for diffusion and adoption of renewable energy technologies, with special emphasis on wind turbines and photovoltaic (PV) modules, were analysed with experience curves. The analysis shows that the possibility of cost reductions of renewable energy technologies is greater than for conventional energy technologies. However, large investments are necessary to make wind turbines and PV modules economically competitive with conventional power plants. The results indicate that the prospects for diffusion and adoption of wind turbines and PV modules will increase if policy instruments are used to bring about diffusion.
08
STEAM
RAISING
Boiler Operation/Design
Analysis of carbon loss from a pulverized coal-fired 98100487 boiler Walsh, P. M. Energy Fuel.!, 1997, 11, (5), 965-971. Our ability to specify the conditions for maintaining a low level of carbon loss from pulverized coal-fired boilers is still limited. This is partly due to problems from the large number of fuel, combustion, and equipment characteristics that may influence carbon burnout. Measurements of the concentration and size distribution of carbon in fly ash from a 30 MW utility boiler have been used to test assumptions regarding the factors controlling carbon conversion. The unexpectedly high carbon losses is attributed principally to air leakage into the furnace and convection sections, causing the furnace gas to be richer than expected from the flue gas analysis. Assuming that the in-leaking air made no contribution to combustion, a calculation of carbon burnout, using the mean chat combustion rate of Hurt and Mitchell and the chat reactivity distribution of Hurt, Lunden, Brehob, and Maloney reproduced the carbon loss and size distribution of unburned particles. It was within a factor of two of the Babcock & Wilcox correlation of carbon loss with stoichiometric ratio. The calculations suggest the char reactivities distribution has a significant influence on the carbon loss and abundance of small particles in the unburned carbon size distribution. Combustion performance of coal-water slurry fuel 98100488 in an off-the-shelf 15,000 lb steam/h fuel oil-designed industrial boiler Pisupati, S. V. et al. Proc. lnt. Tech. Conf. Coal Util. Fuel Syst., 1993, 18, 349-360. Based on the thermal input of the natural gas support fuel, the total combustion efficiency, the coal combustion efficiency, and the boiler efficiency, combustion performance was evaluated. A new burner with airstaging capabilities is needed to achieve 100% performance.
42
Fuel and Energy Abstracts
January 1998
98100489 CWS co-firing on two cyclone-fired electric utility boilers Ashworth, R. A. et al. Proc. Int. Tech. Conf. Coal Util. Fuel Syst., 1997, 22, 159-172. Tests on coal-water slurry (CWS) co-firing were performed on two cyclone electric utility boilers showed that CWS was a viable cyclone co-firing fuel. 98100490 Determination of the operational parameters of steam generation in coal-fired power stations Schlessing, J. VCR Kraftwerkstech., 1997, 77, (9), 731-737. (In German) The paper details tests, operating experiences, operational parameters. and characteristic properties of combustion in a coal-fired power plant regarding coal types from different origin. Criteria for steam generation are stable flame in all operational areas, ignition loss in the filter ash c5%, low emission of NOC, availability, no corrosion, no scaling or slagging on the evaporator and reheater heating surface, and low excess of air. Measures to optimize the firing and coal processing and for process control including comminution, CO/OZ measurements, and rapid analyses are described. 98100491 Dust removal and desulfuritation of flue gas from small-medium type coal-burning boiler Xu, X. et al. Shanghat Huanjing Kexue, 1996, 15, (IO), 22-24. (In Chinese) Reviews dust removal and desulfurization of flue gas from small-medium type coal-burning boiler. 98100492 Effects of fouling on the efficiency of heat exchangers in lignite utility boilers Bergeles, G. et al. Appl. Therm. Ens.. 1997, 17. (X-10). 739-749. The objective of this work is the understanding of the ash deposition mechanism on the surfaces of tubes of heat exchangers in lignite utility boilers. It also attempts to evaluate the influence of fouling on heat exchanger efficiency. For this purpose a numerical model was developed to predict the deposition of particles onto the heat transfer surfaces. The deposition model is combined with a numerical procedure that solves the two phase flow and temperature field around the tubes of the heat exchanger. Predictions of the flow field in both in-line and staggered tube bundles were validated through comparisons with experimental measurements that are conducted in laboratory model geometries. The industrial partner provided observations in full scale geometries of lignite utility boiler heat exchangers that are in current operation. The results of the work performed indicate that the maximum deposit height on the surface of the first tube is reached in about two weeks for a staggered tuhe bundle arrangement. The actual spacing of the tube arrangement is an important factor in reducing the fouling rate while closely spaced tubes in in-line arrangements show signs of bridge formation between subsequent tube rows. 98100493 An experience on carbon loss reduction in a process steam generator firing Indian high ash coals Sathyanathan, V. T. et al. Proc. Int. Tech. Conf. Coal Util. Fuel Syst., 1997. 22, 263-273. Efficiency optimization of boiler performance is possible by reducing the dry gas loss and carbon loss in any coal fired boiler. Experience in a 35 kg/s steam generator designed for a Fertilizer Plant where the operating efficiency was seen to be low mainly because of high carbon loss is discussed here. The boiler is a natural circulation unit, tangentially fired, hi-drum type, with suction type bowl mill and having economizer and air heater. A detailed field study was under taken to understand the reason for such high carbon loss. The coal was analysed in detail via proximate, ultimate and petrographical analyses. Based on these studies, recommendations regarding operations and burner modifications were made to improve upon the carbon loss. After implementation another detailed field study was undertaken when it was found to further halve the carbon loss. After a considerable period of operation of the boiler, more trials and studies were done to validate whether the above performance is sensitive to coal changes. The experience suggests that in the case of high ash Indian coals, due to its virtue of formation, the carbon loss is very high in a low residence time boiler. The reasons were seen to be very poorly reactive macerals, presence of tri-macerals, presence of certain special macerals. like semivitrinite and semi-fusinites in high percentage and impregnation of organics in clay as carbonaceous shale. The Indian high ash coals are found to give large variation in properties due to its virtue of formation which also affects the carbon loss in the boiler and needs a regular watch and tuning of the operational regime. This paper details the full study and analyses carried out, recommendations made and the results obtained. Resultant changes in boiler design concepts for Indian high ash coals are also briefly touched upon. 98100494 Fluidized-bed coal combustion. Part Ill. Steam power plants with pressurized fluidized-bed boilers Nowak, W. Gospod. Paliwami Energ., 1997, 45, (7), 2-10. (In Polish) Describes the development of power stations with pressurized fluidized bed boilers. The design differences between bubbling and circulating fluidized bed boilers are discussed. Particular attention is paid to high-temperature and high-efficiency dust removal systems. Environmental performance of PFBC boilers was also discussed.
Steam raising (boiler operation/design)
Premium power comes from renewable 98100484 fuel at all Jones. C. Power, 1997, 141. (S), 2%30, 32.
fuel-or
no
Strategies for a nation-wide survey of renewable98100485 enerav resources available in each villaae in India Arian%a, A. and Chowhan, P. L. Proc. In&c. Energy Comers. Eng. Conf., 1997. 32, 2181-2186. In India, about 0.6 million villages spread over the length and breadth of the country offer various economic opportunities for judicious exploitation of local resources, holding the key to sustainable development. Energy is the crucial input for sustainable development of the rural areas in the long run and the demand for energy is likely to continue to rise due to the development process and increase in population. Efficient use of non commercial fuels is important, while renewable sources of energy such as sun, wind and hydro potential have to be harnessed simultaneously. The electricity needs of the villages are by and large taken care of by SEBs under the REC schemes. However, there is need for survey of village-wise energy resources from the planning viewpoint, so that least cost energy options could be exercised as between conventional and renewable sources of energy. As data availability is poor, proper statistical analysis is needed to ascertain the load potential and demand in the villages and appropriate system arrangements. The census data 1991 contains valuable information about the villages. However, more details are required to be gathered in the ensuing Census 2001, so that energy plans may be drawn up village-wise/ block-wise/district-wise in a systematic manner based on updated national data. This paper discusses the various strategies required for adoption for a nation-wide survey including classification, selection criteria, division of work, questionnaire and action plan systematically compile the data to prepare a master plan for the use of non-conventional energy sources. Use of experience curves to analyse the prospects 98100488 for diffusion and adoption of renewable energy technology Neij, L. Energy Policy, 1997, 23 The prospects for diffusion and adoption of renewable energy technologies, with special emphasis on wind turbines and photovoltaic (PV) modules, were analysed with experience curves. The analysis shows that the possibility of cost reductions of renewable energy technologies is greater than for conventional energy technologies. However, large investments are necessary to make wind turbines and PV modules economically competitive with conventional power plants. The results indicate that the prospects for diffusion and adoption of wind turbines and PV modules will increase if policy instruments are used to bring about diffusion.
08
STEAM
RAISING
Boiler Operation/Design
Analysis of carbon loss from a pulverized coal-fired 98100487 boiler Walsh, P. M. Energy Fuel.!, 1997, 11, (5), 965-971. Our ability to specify the conditions for maintaining a low level of carbon loss from pulverized coal-fired boilers is still limited. This is partly due to problems from the large number of fuel, combustion, and equipment characteristics that may influence carbon burnout. Measurements of the concentration and size distribution of carbon in fly ash from a 30 MW utility boiler have been used to test assumptions regarding the factors controlling carbon conversion. The unexpectedly high carbon losses is attributed principally to air leakage into the furnace and convection sections, causing the furnace gas to be richer than expected from the flue gas analysis. Assuming that the in-leaking air made no contribution to combustion, a calculation of carbon burnout, using the mean chat combustion rate of Hurt and Mitchell and the chat reactivity distribution of Hurt, Lunden, Brehob, and Maloney reproduced the carbon loss and size distribution of unburned particles. It was within a factor of two of the Babcock & Wilcox correlation of carbon loss with stoichiometric ratio. The calculations suggest the char reactivities distribution has a significant influence on the carbon loss and abundance of small particles in the unburned carbon size distribution. Combustion performance of coal-water slurry fuel 98100488 in an off-the-shelf 15,000 lb steam/h fuel oil-designed industrial boiler Pisupati, S. V. et al. Proc. lnt. Tech. Conf. Coal Util. Fuel Syst., 1993, 18, 349-360. Based on the thermal input of the natural gas support fuel, the total combustion efficiency, the coal combustion efficiency, and the boiler efficiency, combustion performance was evaluated. A new burner with airstaging capabilities is needed to achieve 100% performance.
42
Fuel and Energy Abstracts
January 1998
98100489 CWS co-firing on two cyclone-fired electric utility boilers Ashworth, R. A. et al. Proc. Int. Tech. Conf. Coal Util. Fuel Syst., 1997, 22, 159-172. Tests on coal-water slurry (CWS) co-firing were performed on two cyclone electric utility boilers showed that CWS was a viable cyclone co-firing fuel. 98100490 Determination of the operational parameters of steam generation in coal-fired power stations Schlessing, J. VCR Kraftwerkstech., 1997, 77, (9), 731-737. (In German) The paper details tests, operating experiences, operational parameters. and characteristic properties of combustion in a coal-fired power plant regarding coal types from different origin. Criteria for steam generation are stable flame in all operational areas, ignition loss in the filter ash c5%, low emission of NOC, availability, no corrosion, no scaling or slagging on the evaporator and reheater heating surface, and low excess of air. Measures to optimize the firing and coal processing and for process control including comminution, CO/OZ measurements, and rapid analyses are described. 98100491 Dust removal and desulfuritation of flue gas from small-medium type coal-burning boiler Xu, X. et al. Shanghat Huanjing Kexue, 1996, 15, (IO), 22-24. (In Chinese) Reviews dust removal and desulfurization of flue gas from small-medium type coal-burning boiler. 98100492 Effects of fouling on the efficiency of heat exchangers in lignite utility boilers Bergeles, G. et al. Appl. Therm. Ens.. 1997, 17. (X-10). 739-749. The objective of this work is the understanding of the ash deposition mechanism on the surfaces of tubes of heat exchangers in lignite utility boilers. It also attempts to evaluate the influence of fouling on heat exchanger efficiency. For this purpose a numerical model was developed to predict the deposition of particles onto the heat transfer surfaces. The deposition model is combined with a numerical procedure that solves the two phase flow and temperature field around the tubes of the heat exchanger. Predictions of the flow field in both in-line and staggered tube bundles were validated through comparisons with experimental measurements that are conducted in laboratory model geometries. The industrial partner provided observations in full scale geometries of lignite utility boiler heat exchangers that are in current operation. The results of the work performed indicate that the maximum deposit height on the surface of the first tube is reached in about two weeks for a staggered tuhe bundle arrangement. The actual spacing of the tube arrangement is an important factor in reducing the fouling rate while closely spaced tubes in in-line arrangements show signs of bridge formation between subsequent tube rows. 98100493 An experience on carbon loss reduction in a process steam generator firing Indian high ash coals Sathyanathan, V. T. et al. Proc. Int. Tech. Conf. Coal Util. Fuel Syst., 1997. 22, 263-273. Efficiency optimization of boiler performance is possible by reducing the dry gas loss and carbon loss in any coal fired boiler. Experience in a 35 kg/s steam generator designed for a Fertilizer Plant where the operating efficiency was seen to be low mainly because of high carbon loss is discussed here. The boiler is a natural circulation unit, tangentially fired, hi-drum type, with suction type bowl mill and having economizer and air heater. A detailed field study was under taken to understand the reason for such high carbon loss. The coal was analysed in detail via proximate, ultimate and petrographical analyses. Based on these studies, recommendations regarding operations and burner modifications were made to improve upon the carbon loss. After implementation another detailed field study was undertaken when it was found to further halve the carbon loss. After a considerable period of operation of the boiler, more trials and studies were done to validate whether the above performance is sensitive to coal changes. The experience suggests that in the case of high ash Indian coals, due to its virtue of formation, the carbon loss is very high in a low residence time boiler. The reasons were seen to be very poorly reactive macerals, presence of tri-macerals, presence of certain special macerals. like semivitrinite and semi-fusinites in high percentage and impregnation of organics in clay as carbonaceous shale. The Indian high ash coals are found to give large variation in properties due to its virtue of formation which also affects the carbon loss in the boiler and needs a regular watch and tuning of the operational regime. This paper details the full study and analyses carried out, recommendations made and the results obtained. Resultant changes in boiler design concepts for Indian high ash coals are also briefly touched upon. 98100494 Fluidized-bed coal combustion. Part Ill. Steam power plants with pressurized fluidized-bed boilers Nowak, W. Gospod. Paliwami Energ., 1997, 45, (7), 2-10. (In Polish) Describes the development of power stations with pressurized fluidized bed boilers. The design differences between bubbling and circulating fluidized bed boilers are discussed. Particular attention is paid to high-temperature and high-efficiency dust removal systems. Environmental performance of PFBC boilers was also discussed.