ES357411A1 - Procedure for the obtaining of sulfuric acid by catalytic oxidation under gas pressure with small content in so2. (Machine-translation by Google Translate, not legally binding) - Google Patents

Abstract

Sulphuric acid is made by the catalytic oxidation of gases having an S0 2 content of not more than 12% volume wherein the catalysis is carried out at a pressure of 3-9 bars absolute either in one or two catalytic stages, each catalytic stage comprising passing the gas through one or more layers of catalyst and absorbing the S0 3 formed in water, the residue gases leaving the final absorption step being heated prior to expansion. Gases obtained by burning sulphur or gases obtained by roasting sulphides or the decomposition of sulphates and having S0 2 contents of 4-9% may be used. The process may be performed in a single catalytic stage comprising passing the gas through three catalyst layers before SO 3 absorption or in two catalytic stages, the first comprising two or three catalyst layers and an absorption step and the second comprising a single layer and an absorption step. The gases leaving the final absorption may be heated by heat exchange with reactant gases and/or through direct or indirect combustion of fuel. A variety of suitable heat exchanger arrangents are disclosed. The gases may be expanded through a turbine, cooled and exhausted at at least 150 C.