03952 Fluidized-bed combustion of coal. Part II. Emission of pollutants from fluidized-bed boilers

03952 Fluidized-bed combustion of coal. Part II. Emission of pollutants from fluidized-bed boilers

08 Steam raising (boiler operation/design) emissions. This paper reviews the results of cyclone boiler modellmy. and also reviews some results of in...

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08

Steam raising (boiler operation/design)

emissions. This paper reviews the results of cyclone boiler modellmy. and also reviews some results of initial cyclone testing related to the results of the modelling efforts. 97103942 Combustion performance of coal-water slurry fuel in an off-the-shelf 15,000 lb steam/h fuel oil-designed industrial boiler Pisupati, S. V. Proc. Int. Tech. Conf: Coal UtiL Fuel Syst.. 1993, 18, 349360. 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 1005 performance. 97103943 Comparison of fluidized bed and pulverized coal boilers based on environmentally related factors Pope, F. B., 111 and Ghayal, D. B. Proc. Int. Tech. Conf. Coal Uril. Fuel syst., 1997, 22, 641-658. Pulverized coal boilers (PC) and circulating fluidized bed coal boilers (CFB) were compared based on potential impact on ambient air quality. The comparison was made for two 100 MW PC and two 100 MW CFB systems based on a specific fuel source. The PC system may be the chosen technology for exceptionally clean or even compliant coal. However, for projects using coals with a moderate sulfur content and a wide variation in heating, volatiles content, and other factors, CFB units generally have an operating and environmental edge over the PC units. The choice depends on the coal quality, the availability of advanced SOz control systems, and the importance of other aspects of plant design and operation. The best way to assess appropriate boiler technology is to examine all the financial and technical aspects, and then consider environmental factors if the cost analysis for the PC system (with controls) and the CFB options are comparable. 97103944 A comparison of premium coal fuel supply options for the conversion of industrial-sized boilers Schaal. A. M. and Gordon. R. L. Proc. Int. Tech. Conf. Coal (iti/. Fuel syst., 1994, 19, 317-387. Technologies are being developed by the Consortium for Coal-Water Slurry Fuel Technology to allow the United States to decrease its dependence on foreign oil and increase its use of coal. This work is being performed under the auspices of the Department of Energy (DOE) for the Department of Defense (DOD). The existing programme is aimed at the development and demonstration of integrated combustion systems that would include coal-fuel preparation, delivery, storage and transport to the burner, combustion, heat recovery, ash collection, flue gas treatment, and system control. The objective of Phase I is to develop and evaluate technologies for retrofitting an existing DOD oil-fired boiler to fire premium coal fuels such as micronized coal-water slurry fuels (MCWSFS) and dry, micronized coal (DMC). Basic economics are developed and comparisons are made between the MCWSF and DMC fuels. MCWSF has a cost advantage over DMC at the point of supply only when considering supply of multiple retrofitted boilers from a single slurry preparation plant. However, when transportation charges are added, DMC is delivered to the boiler at a lower cost than MCWSF. The implications of the fuel cost differential between MCWSF and DMC towards capital costs of retrofitting are also discussed. 97m3945 CWS co-firing on two cyclone-fired electric utility boilers Ashworth. R. A. et al. Proc. Int. Tech. Co& Coal Util. Fuel SW.. 1997. 22. 159-172. The paper presents coal-water slurry (CWS) co-firing demonstrations performed on 2 cyclone electrical utility boilers. Both tests indicated that CWS was a viable cyclone co-firing fuel. 97103946 Demonstration of a high efficiency advanced coal combustor for an industrial boiler Rini, M. J. et al. Proc. Int. Tech. Conf. Coal Util. Fuel Syst., 1993, 18, l324. This study concerns the feasibility of retrofitting a gas/oil-designed industrial boiler to burn micronized coal. Design implementation and test results are described. The effective control of NO,, high combustion efficiency, acceptable fan head requirements, flame shaping capability and turn down required of a commercial retrofit coal burner are all demonstrated in test results. Long-term operation is expected to yield the technical and economic data required to confirm commercial viability of the system. 97103947 Development and design of an advanced coal-fired low-emission boiler system Regan, J. W. et al. Proc. Int. Tech. Conf. Coal Util. Fuel Syst., 1994, 19, ll89. The U.S. Department of Energy (DOE) has established a four-phase project for ‘Engineering Development of Advanced Coal-Fired LowEmission Boiler Systems’ (LEBS), one of two projects in the DOE’s ‘Combustion 2000 Program. The project’s primary objective SO, and NO, emissions limitation to l/3 of the New Source Performance Standards (NSPS) requirements and particulates to l/2 NSPS requirements. Furthermore, in reaching these emission levels the project aims to prevent

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Fuel and Energy Abstracts

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increases in plant heat rate or cost of electricity, to reduce the amount of waste produced, and to make the waste more readily disposable. Ultimately, a design data base will be produced allowing future pulverized coal-fired plants to meet the stated objectives, as well as a preliminary design of a commercial generating unit. This paper reports the results of Phase IA, devoted to producing the Management Plan for all four Phases, concept development and evaluation, subsystem preliminary design uncertainties analysis, and a research and development plan for Phase IB. The status of Phase IB is discussed, consisting of component definition, the preliminary design of a commercial generating unit (CGU), and research and development plans for Phase II. Plans for future work are also reported.

97lO3948 Environmental impact of Orimulsion combustion in large utility boilers Ailen, J. W. and Beal, P. R. Proc. Int. Tech. Conf. Coal Util. Fuel Syst.. 1997, 22.443-450.

The authors

discuss emissions

from utility boilers fired with Orimulsion.

97103949 Evaluation of hybrid SNCRISCR for NO, abatement on a utility boiler Albanese, V. et al. Proc. lnt. Tech. Conf. Coal Util. Fuel Syst.. IY96. 21. lS86.

For effective moderate to extensive NO, reductions, hybrid combinations of selective non-catalytic reduction (SNCR) and selective catalytic reduction (SCR) are a particularly flexible method. The cost of such a method is generally lower than a fully-engineered SCR retrofit. Reductant utilization observed in recent field work and ramifications of increased use on lifecycle costs of NO, reduction, validated by owners and operators, are discussed.

97l03950 Experience from conversion of a 640 MW coal-and oil-fired unit into Orimulsion Meisingset, L. Proc. Int. Tech. Conf Coal Util. Fuel Syst., 1997. 22. 4hl412. The paper describes the conversion of a 640 MW coal- and oil-fired boiler to firing with Orimulsion (natural bitumen emulsion). The operating experience of the converted unit is characterized, including its environmental performance.

97103951 An experience on carbon loss reduction in a process steam generator firing Indian high ash coals Sathyanathan, V. T. et al. Proc. fnt. Tech. Conf Coal Util. Fuel Syst.. lYY7, 22, 263-273. By reducing the dry gas loss and carbon loss in any coal fired boiler. operating efficiency can be optimized. Experience in a 35 kg/r steam generator designed for a fertilizer plant where the operating efficiency was seen to be low mainly due to high carbon loss. The boiler is a natural circulation unit, tangentially fired, bi-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 and air tuning was found to affect the carbon burn out significantly by about 40%. Based on these studies, recommendations regarding operations and burner modifications were made to improve carbon loss figures. After implementation of the recommendations, a detailed field study was undertaken, discovering a further reduction of carbon loss by half. Further trials and studies were done after a considerable period of boiler operation to validate whether the above performance is sensitive to coal changes. This experience shows 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 for such a behaviour were seen to be very poorly reactive macerals, presence of tri-macerals, presence of certain special macerals in high percentage and impregnation of organics in clay as carbonaceous shale. The experience has led to changes in boiler design concepts for Indian high ash coals which are also briefly touched upon in this paper.

97103952 Fluidized-bed combustion of coal. Part II. Emission of pollutants from fluidized-bed boilers Nowak, W. Gospod. Paliwami Energ., 1996, 44, (7), 2-l 1. (In Polish) The environmental performance of commercial-scale fluidized bed boilers is assessed. Emissions of concern include SOa, NO,, NzO. CO and trace elements. Fluidized bed boilers can meet the most stringent of current emission limits with low costs, high efficiency and reliability of operation.

97103953 Incineration of a clarifier sludge suspension in a coal fines-fired boiler Stroeer, K. and Koritz, D. Ger. Offen. DE 19,.545,236 (Cl. F23G5/00), 28 May 1997, Appl. 19,545,236, 22 Nov 1995, 4 pp. (In German) Partial combustion of the clarifier sludge takes place in the holler in the wall region. The remaining sludge is pulled into the afterburner along with coal fines and flue gases and incinerated in the coal fines burner.