PRODUCTION OF SULPHUR TRIOXIDE, SULPHURIC ACID AND OLEUM

摘要

1380692 Manufacture of sulphuric acid CANADIAN INDUSTRIES Ltd 18 Oct 1972 [16 Nov 1971 6 April 1972] 53087/71 and 15902/72 Heading C1A Sulphuric acid is prepared by the catalytic conversion of gaseous sulphur dioxide to sulphur trioxide in the presence of dry air and under a pressure of at least 2 atmospheres gauge wherein the converted gas stream is fed under pressure to an absorbing unit through which essentially sulphur dioxide free sulphuric acid is circulated to absorb the sulphur trioxide and unconverted sulphur dioxide from the converted gas stream, the acid emerging from the absorbing unit being depressurized and the sulphur dioxide being stripped therefrom by means of an essentially sulphur dioxide free gas and the resulting essen tially sulphur dioxide free acid being cooled and at least a part thereof recirculated to the absorbing unit. Air may be used in the stripping operation and this may be used subsequently in the catalytic conversion stage as the source of dry air. The stripping may be conducted under super-atmospheric pressure and at a temperature higher than that of the absorbing stage. Part of the converted gas may be fed to an oleum unit, from which oleum may be recovered and distilled to produce SO 3 . The SO 2 in the sulphuric acid stream leaving the absorbing unit may be oxidized by injection of an oxidizing agent such as hydrogen peroxide or ozone.