The report gives results of a study to identify and classify 22 hot gas cleanup (HGC) processes for desulfurizing reducing gases at above 430 C according to absorbent type into groups employing solid, molten salt, and molten metal absorbents. It describes each process in terms of its status, chemistry, operating characteristics, problems, and uncertainties. It assesses the applicability of none HGC processes to a variety of coal gasification systems for several end uses for the product gases. It evaluates advantages and disadvantages of HGC relative to conventional low temperature cleanup systems with respect to thermal efficiency, the presence and/or emissions of tars, particulates, and NOx, and corrosion. It also presents economic comparisons between HGC and low temperature desulfurization. HGC processes are best suited for combined-cycle and on-site combustion applications coupled with low- or intermediate-Btu gasifiers. The Kennecott and MERC processes are applicable for desulfurizing gases at high temperatures. HGC processes provide greater overall efficiencies than low temperature desulfurization. Processing gases at high temperatures result in increased NOx emissions. Particulate removal at high temperatures is inefficient and corrosion problems increase. HGC processes complicate and add uncertainties which economically offset some thermal efficiency.

"Dynalectron Corporation/Applied Research Division." "July 1979." Includes bibliographical references. "Contract no. 68-02-2601, program element no. EHE623A."