FIELD: petroleum processing. SUBSTANCE: invention relates to chemical purification of gaseous by-products in petroleum processing and, more specifically, to a method of decomposing hydrogen sulfide contained in crude gaseous stream. Method consists in interaction of hydrogen sulfide-containing crude gas with polar organic solvent containing anthraquinone and, in some cases, a complexing agent dissolved in it. Primarily obtained are sulfur and dissolved anthrahydroquinone. The latter is then catalytically dehydrogenated into anthraquinone and hydrogen. According to invention, relatively small water quantities (0.6 to 5.0 mol) are added to polar solvent to increase amount of elementary sulfur precipitated. Yield of hydrogen is also augmented when water is added into starting material or during sulfur production. EFFECT: enhanced process efficiency. 15 cl, 4 dwg
