Chemical desulfurization of coal: a misunderstood technology

The U.S. Department of Energy (DOE) studied two processes for coal desulfurization: the Oxydesulfurization process developed at the DOE Pittsburgh Energy Technology Center and the Gravichem process being developed by TRW Systems and Energy Group. For each process, an additional case was made by assuming major process modifications to combine physical beneficiation techniques with chemical desulfurization technologies in order to reduce capital and operating costs while maintaining the same product standard. The modified Gravichem process showed a 24.4% reduction in capital cost and a 17.6% reduction in operating cost. For the modified Oxydesulfurization process, capital cost was lowered 21.6% and operating costs, 21.4%. Precombustion coal cleaning appears to be more economically justifiable than previously thought. The need for continuing research is indicated.