Methods for the removal of gaseous impurities from mixed gas streams

Abstract

Methods are disclosed for the purification of mixed gas streams containing hydrogen sulfide, carbon dioxide, carbon monoxide, sulfur, hydrogen, and methane and other hydrocarbon gases, and mixtures thereof, by the use of an oxidizing reactive solid. In one method, the oxidizing reactive solid is, in a first step, contacted with the mixed gas stream which may contain, among other gases, hydrogen sulfide and carbon dioxide. The reactive solid removes the hydrogen sulfide in the form of elemental sulfur with no detectable formation of sulfur oxide. The reactive solid also partially removes the carbon dioxide from the mixed gas stream. In the second step of the first method, the oxidizing reactive solid is regenerated by flowing air. In a second method of the present invention, mixed gas streams, containing hydrogen sulfide and oxygen in an approximate stoichiometric amount, are contacted with the solid, and hydrogen sulfide is converted directly to sulfur with minimal formation of compounds of sulfur. The oxidizing reactive solid has the general formula D-M-O, wherein D is chosen from the alkali metals or alkaline earth metals comprising sodium, potassium, lithium, calcium or magnesium; M represents a transition metal selected from the group comprising manganese, copper, and iron, and groups IB, VB, VIB, VIIB or VIII from the Periodic Table; and O designates oxygen.