Temperatures, industrial H2SO4 making

Industrial H2SO4 making input and output acid temperatures (Table 9.3) are typically ... 

Fig. 21.1. Heat transfer flowsheet for single contact, suliiir burning sulfuric acid plant. It is simpler than industrial plants, which nearly always have 4 catalyst beds rather than 3. The gaseous product is cool, SO3 rich gas, ready for H2SO4 making. The heat transfer product is superheated steam. All calculations in this chapter are based on this figure s feed gas composition and catalyst bed input gas temperatures. All bed pressures are 1.2 bar. The catalyst bed output gas temperatures are the intercept temperatures calculated in Sections 12.2, 15.2 and 16.3.

Of course, output acid temperature will increase if mass% H2SO4 in output acid is allowed to increase with increasing volume% SO3 in H2SO4 making tower input gas. Fig. 24.4. This is the case when input acid flowrate and mass% H2SO4 are kept constant while volume% SO3 in input gas increases. This is usual industrial practice. 

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