ES337098A1 - A Process for Catalytically Converting SO2-Containing Gases to Produce SO3 and Sulphuric Acid - Google Patents

Abstract

Sulphur trioxide and sulphuric acid are produced from sulphur dioxide containing gases by a catalytic process in which the gases are dried and conducted together with oxygen through a multi-stage catalytic converter in each stage of which the gases are reacted over one catalyst hurdle to convert sulphur dioxide into sulphur trioxide, and the SO 3 -containing gases leaving each stage of the converter are cooled in at least two stages to the operating temperature of an appropriate stage of a multi-stage absorber, prior to being fed into the absorber where the sulphur trioxide is absorbed with the aid of H 2 SO 4 , the gases discharged from the respective absorber stage, except the last, being heated to the operating temperature of the next catalytic conversion stage by heat exchange with the gases to be subjected to absorption in that absorber stage. The operating temperature of each absorber stage except the last one is from 100 to 200 C., the last being operated at 100 to 150 C. The sulphur trioxide containing gases are cooled in a plurality of stages to 110 to 140 C. before entering the respective absorber stage as shown in Fig. 1. In this Figure the SO 2 -containing gas obtained by burning sulphur in furnace 8 are fed into a first catalytic stage 13 after being cooled in waste heat boiler 11. After partial conversion the gases are cooled in an intermediate heat exchanger 15 and an economizer 16 and then pass into an intermediate absorber 18. The discharged gases are then heated in heat exchanger 15, and fed into a second catalytic stage 22. After partial conversion the gases are cooled in an intermediate heat exchanger 24 and an economizer 25 and then passed into absorber 27. The gases enter the final catalytic stage 31 after passing through heat exchanger 24. The gases were then cooled in steam generator 33, and air preheater 6, and passed into a final absorber 35.