Process for recovering as sulfur the compounds H2S, SO2, COS and/or CS2 in a tail gas from a sulfur plant

摘要

A process is provided to recover residual H₂S, SO₂, COS and CS₂ in the tail gas from a sulphur recovery process. The tail gas is oxidized and hydrolyzed at a temperature of from 180° C. to 700° C. to provide an oxidized and hydrolyzed gas stream containing substantially no COS or CS₂ and having a concentration by volume of H₂S and SO₂ such that the H₂S concentration minus twice the SO₂ concentration is from 0.25% to 0.5%. Then the gas stream from the hydrolysis is passed over a Claus catalyst, for example based on alumina and/or titanium oxide, for the reaction of H₂S with SO₂ to form sulphur and provide a gas stream with substantially no SO₂. The resulting gas stream from the Claus reaction together with a gas containing free oxygen is then passed over an oxidation catalyst, such as one of more oxides or salts of Ni, Co, Fe, Cu, Ag, Mn, Mo, Cr, W or V, deposited on a support, such as bauxite, activated aluminia, silica, titanium oxide, zirconium oxide, zeolite or activated carbon to form sulphur and release a purified gas stream containing substantially no sulphur compounds.