A medium-temperature process for removal of hydrogen sulfide from sour gas streams with aqueous metal sulfate solutions

A process is proposed for removing hydrogen sulfide from coal gas at its adiabatic saturation temperature. The coal gas would be contacted with a metal sulfate solution in a Venturi scrubber, leading to the formation of a solid metal sulfide. This metal sulfide would be oxidized with ferric ion, forming sulfur and regenerating the metal sulfate solution. Ferrous ion would be reoxidized with air. Experimental work was done on the absorption of hydrogen sulfide into zinc and copper sulfate solutions. The rate of absorption into zinc sulfate is a strong function of pH and is unsatisfactory at the pH proposed for this process