Study of seed-reprocessing systems for open-cycle coal-fired MHD power plants

Abstract

Of the several processes that are capable of separating sulfur from potassium sulfate, the process developed by Pittsburgh Energy Research Center (PERC), and the Formate process were selected for the detailed mass and energy balance calculations. As a basis for the calculations, an MHD power plant of 450 Mwt size and burning Illinois number 6 coal was selected. In the mass balance calculations, the role played by various trace impurities was included to the extent of current knowledge about such impurities and their impacts on process chemistry. The results given should be considered as preliminary values because various simplifying assumptions were made and factors such as heat losses and component efficiencies were excluded. On the basis of net energy requirements, the Formate process showed a slight advantage; however, it produced a potentially unacceptable sludge as the sulfur-containing waste. In both the processes, the regenerated seed material was found to contain significant amounts of sodium and other impurities, which may warrant some kind of a post-treatment step before injecting the regenerated seed material in the MHD combustor.