Maximum SO2 Oxidation

Chapters 10 and 11 discuss oxidation of SO2 when warm SO2, O2, N2 feed gas descends a catalyst bed. They do so in terms of  

Together, they indicate that maximum oxidation in a catalyst bed is obtained where a feed gas s  

For an intercept calculation to be valid, its heatup path and equilibrium curve must be for the same feed gas. Each intercept calculation must, therefore, specify a feed gas 

A calculated intercept is valid only for these specified values. 

Temperature, K Heatup path % SO2 oxidized, I Equilibrium % SO2 oxidized, 

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Fig. 10.1 indicates that maximum SO2 oxidation is achieved when Reaction (1.1) comes to equilibrium. The next few sections show how this maximum is predicted. 

Catalyst bed SO2 + /2O2 —SO3 oxidation is represented by heatup paths and equilibrium curves. Maximum SO2 oxidation occurs where a feed gas s heatup path intercepts its equilibrium curve. 

Fig. 20.5. 3 - 1 acid plant with one Cs catalyst bed (660 K gas input) and three K, Na catalyst beds (690 and 720 K). Maximum SO2 oxidation is obtained with the Cs catalyst in bed 4, i.e. after H2SO4 making. Bed 3 Oust before H2SO4 making) is nearly as good. The calculations are all based on Table 20.1 s values - except for gas input temperature. 

Chapter 15 indicates that maximum SO2 oxidation in a 2" catalyst bed occurs where the bed s ... 

Maximum SO2 oxidation Heatup path-equilibrium curve intercepts... 

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