Coal cleaning plus scrubbing proves economic desulfurization combination

The combination of coal cleaning and flue-gas desulfurization can be a better choice than scrubbers alone. An analysis of sulfur and ash removal for three coal types, West Kentucky No. 9, 11, and 12, shows that precombustion cleaning reduces the capital investment and operating costs for the scrubber's absorbent handling and preparation system and for sludge disposal. Generally, the savings cover the cost of the coal preparation plant. If the EPA requires chemical fixation of scrubber sludge, the economics will tilt more in favor of the combination of precombustion cleaning and flue gas desulfurization. The greatest potential savings attributable to coal cleaning, however, are reduced maintenance costs and increased rated capacity. Precombustion cleaning would allow an increase in availability and capacity and reduced operating costs. Recently proposed EPA regulations preclude the use of coal cleaning alone as a method for complying with sulfur dioxide standards in new electric utility boilers. However, coal cleaning with scrubbers may be used in some cases as a cost-effective method of meeting the revised New Source Performance Standards.