Power generation, coal gasification

Y. Wajiki. "Current Status of R D for 200T/d Entrained Flow Coal Gasification Power Generation Pilot Plant." Presented at the EPRI Tenth Annual Conference on Gasification Power Plants, San Francisco, California, October 15-18, 1991. 

Eig. 16. Coal gasification power plant HRSG = heat recovery steam generator. Courtesy of Black and Veatch. 

The use of coal as a fuel and the varied, often detrimental, effects of the mineral matter on the fuel properties of coal has been a source of concern for consumers (Alpern et al., 1984). Even the interactions of the mineral constituents themselves (Table 7.9) have directed interest toward the mineral constituents of coals but with the tendency to an increased use of coal for power generation as well as for gasification and conversion plants that will enable coal to act as a source of liquid and gaseous fuels. Therefore, methods by which the mineral matter can be evaluated have been a constant target for quantitative and qualitative improvement. 

Direct Carbon Fuel Cells (DCFC). In direct carbon fuel cells, solid carbon (presumably a fuel derived from coal, pet-coke or biomass) is used directly in the anode, without an intermediate gasification step. Concepts with solid oxide, molten carbonate, and alkaline electrolytes are all under development. The thermodynamics of the reactions in a DCFC allow very high efficiency conversion. Therefore, if the technology can be developed into practical systems, it could ultimately have a significant impact on coal-based power generation. 

The CAAA mandates the reduction of SO2 emissions from utility power plants in the United States to a maximum or "cap" of 8.9 million tons per year by January 1, 2000 and thereafter. Any expansion in capacity of coal-based power generation will be allowed to emit SO2 only if SO2 emissions are reduced elsewhere in the utility system. Since coal gasification combined cycle power plants can be designed for over 99% sulfur recovery, they can be built with minimum offsetting impact for SO2 control on other utility power plants. 

Iyengar, R. and Haque, R. (1991) Gasification of high-ash Indian coals for power generation. Fuel Processing Technology, 27 (3), 2A7-262. 

The importance of coal gasification as a means of produciag fuel gas(es) for iadustrial use caimot be underplayed. But coal gasification systems also have undesirable features. A range of undesirable products are also produced which must be removed before the products are used to provide fuel and/or to generate electric power (see Power generation) (22,41). 

Methanol, a clean burning fuel relative to conventional industrial fuels other than natural gas, can be used advantageously in stationary turbines and boilers because of its low flame luminosity and combustion temperature. Low NO emissions and virtually no sulfur or particulate emissions have been observed (83). Methanol is also considered for dual fuel (methanol plus oil or natural gas) combustion power boilers (84) as well as to fuel gas turbines in combined methanol / electric power production plants using coal gasification (85) (see Power generation). 

For central station power generation the open cycle system using electrically conducting coal combustion products as the working fluid is employed. The fuel typically is pulverized coal burned directly in the MHD combustor, although in some plant designs cleaner fuels made from coal by gasification or by beneficiation have been considered (8—10) (see Fuels, synthetic). 

Combustor. In the majority of MHD plant designs the MHD combustor bums coal directly. Because MHD power generation is able to utilize pulverized coal in an environmentally acceptable fashion, there is usually no need to make cleaner fuels from coal, eg, by gasification or by beneficiation. A discussion of combustion techniques for MHD plants is available (70). 

G. W. Roberts, N. K. Dicciani, J. Klosek, Conference on Coal Gasification and Synthetic Fuels for Power Generator, San Francisco, Calif., Apr. 14—18,1985. 

Coal Gasification Combined Cycle Power Generation... 

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