FIELD: chemical industry, more particularly complete oxidation of hydrogen sulfide to sulfur in amount from 0.7 to 3 vol.%. SUBSTANCE: method is carried out in catalytic oxidation set-up which uses several catalytic oxidation stages disposed in series and includes initial stage, final stage and optionally at least one intermediate stage, each stage containing promoted catalyst of selective oxidation of H2S to sulfur and operating at temperature below then dew point of sulfur resulting from oxidation, H2S,-containing gas to be purified is fed to catalytic oxidation initial stage inlet and said gas is allowed to pass through each catalytic oxidation stage in contact with oxidation catalyst contained therein, and free oxygen-containing gas is forced into each catalytic oxidation stage to effect catalytic oxidation in each stage, at least partial oxidation of H2S gas passing through said stage to sulfur by means of oxygen gas- containing free oxygen. The resulting sulfur is deposited on catalyst of each catalytic oxidation stage, and purified gas having low residual H2S content is removed at final catalyst oxidation stage outlet. H2S, containing gas is preheated to 80-100 C at inlet of each catalytic oxidation stage, amount of free oxygen containing gas is regulated and fed into initial stage and into each of optional intermediate catalytic oxidation stages so that temperature of gas medium at outlet as each of catalytic oxidation stages operating under adiabatic conditions is not higher than maximum θs temperature of temperature range at which oxidation catalyst is capable of promoting desired selective oxidation of H2S to sulfur and is not above 150 C. Amount of free oxygen-containing gas fed into final catalytic oxygen stage is regulated to secure desired excess of oxygen in purified gas which causes complete oxidation of H2S, passing through final stage, and H2S is oxidized in final catalytic oxidation stage at temperature not higher than θs and is not above 150 C, and final catalytic stage is optionally cooled by indirect heat exchange with cold liquid-flowing medium. Yield of sulfur is more than 99.9%. EFFECT: more efficient oxidation method. 10 cl, 1 dwg
