Equilibrium SO2 oxidation

Fig. 10.2 shows a typical equilibrium % SO2 oxidized vs. temperature curve for the Fig. 10.1 catalyst bed. This chapter and Appendix D show how it is prepared. 

Fig. 17.1. Effect of C02-in-feed-gas on 1st catalyst bed heatup path and heatup path-equilibrium curve intercept. C02 increases heatup path slope and slightly increases intercept (equilibrium) % SO2 oxidized. Section 17.4. Appendix Table R.l describes the 10 volume% C02 intercept calculation.

Temperature, K Heatup path %S02 oxidized, aa Equilibrium % SO2 oxidized, 0Eaftcr... 

This appendix shows that C02 has no affect on equilibrium % SO2 oxidized equations, e.g. Eqn. (10.12). 

Fig. 7.4. Maximum attainable (equilibrium) SO2 oxidation as a function of reaction temperature. It decreases markedly with increasing temperature. Calculation and plotting of this curve are described in Chapter 10.

Fig. 7.5 also shows that SO2 oxidation and gas heat up end when the heatup path reaches Fig. 7.4 s equilibrium % SO2 oxidized curve. 

This equation permits equilibrium % SO2 oxidized to be calculated from... 

Equilibrium % SO2 oxidized (O ) is related to equilibrium temperature by combining Eqns. (10.11) and (10.12), which gives ... 

Fig. 10.2 plots this equation as described in Appendix D. The figure emphasizes that equilibrium % SO2 oxidized increases with decreasing equilibrium temperature. 

Fig. 10.3 shows the effect of equilibrium pressure on equilibrium % SO2 oxidized. Equilibrium % SO2 oxidized increases slightly with increasing equilibrium pressure. 

Fig. 10.3. Equilibrium % SO2 oxidized as affected by equilibrium pressure, P,. Equilibrium % SO2 oxidized is seen to increase slightly with increasing pressure, Eqn. (10.7). Industrial catalyst bed pressures are typically 1 to 1.4 bar.

Fig. 10.4. Effect of feed gas O2 concentration on equilibrium % SO2 oxidized. High O2 concentration gives high equilibrium % SO2 oxidized and vice versa.

At 894 K and above, however, heatup path % SO2 oxidized is greater than equilibrium % SO2 oxidized. This is, of course, impossible because equilibrium % SO2 oxidized cannot be exceeded up a heatup path. 

Maximum (equilibrium) % SO2 oxidized occurs, therefore, between 893 K and 894 K. Interpolation shows that it occurs at ... 

Table D.l. Excel spreadsheet for calculating Fig. 10.2 equilibrium points from Eqn. (10.13). The calculation method is previous page. Equilibrium % SO2 oxidized is seen to increase with decreasing equilibrium temperature. 

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