Catalytic oxidn. of sulphur di:oxide to tri:oxide - in sulphuric acid mfr., by double conversion using wall heat exchange to increase heat exchange intensity

摘要

Catalyst oxidn. of SO2 to SO3 in H2SO4 mfr. by double conversion, with intermediate absorption, involves contacting the SO2-contg. gas and O2 with a V catalyst at elevated temp. in a chamber with >=3 oxidn. levels, the first forming the first oxidn. stage and the others the second oxidn. stage. Part of the SO2 stream is introduced at each level, whilst the SO3 formed in the first oxidn. stage is absorbed and the gas leaving the absorption stage is heated in wall heat exchangers and passed to the second oxidn. stage. The SO2 formed in the second stage is absorbed in the final absorber, from which a gas with a low SO2 content is discharged. The novel features are as follows, the gas passed from intermediate absorption to the second oxidn. stage is heated in 2 stages, first by the gas from the past plate of the first oxidn. stage and then by the gas from the preceding plate of this stage. The gas passed to intermediate absorption is cooled first by the gas passing to the second conversion stage and then by air passing to the combustion of S. More intensive heat exchange is attained, whilst the size and wt. of the heat exchanger and current consumption are reduced.