Effect of Feed Gas Temperature on Intercept

The high intercept % SO2 oxidized gives efficient SO3 and H2SO4 production. It also 

SO2 + /2O2 — SO3 oxidation efficiency in a T catalyst bed is always below 80%. This is totally inadequate for efficient, low SO2 emission H2SO4 production. 

This limitation is overcome industrially by passing T catalyst bed eidt gas through two or more gas cooling/catalytic oxidation steps - bringing SO2 oxidation efficiency up to 

Multi-catalyst bed processing is discussed in Chapter 13 onwards. 

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Fig. 12.2 shows the effect of feed gas temperature on intercept temperature and % SO2 oxidized. It indicates that cool feed gas gives ... 

Fig. 12.5. Effect of feed gas 02 strength on constant S02 strength heatup paths, equilibrium curves and intercepts. Intercept temperature and % S02 oxidized increase slightly with increasing 02-in-feed-gas. Heatup path is barely affected by 02 strength - 3 paths are superimposed on this graph. The effect is small because ...

Table 17.2 shows 1st catalyst bed intercept temperature-% S02 oxidized points with and without 0.2 volume% S03 in feed gas. The presence of 0.2% S03 is shown to have little effect on intercept % S02 oxidized. 

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