Double contact advantage

Double contact acidmaking always gives more efficient SO2 + /2O2 — SO3 oxidation than single contact acidmaking. This leads to  

The reason for double contact s high SO2 oxidation efficiency is given in Figs. 19.6 and 19.7. 

The starting point for this chapter s calculations is the product gas from a specific  

The exit gas from the 3 catalyst beds is specified to be that in Section 16.4. It contains  

This gas goes to intermediate H2SO4 making where 100% of its SO3 is specified as being removed as H2S04(f). The gas departing this step contains  

The increase in % SO2 oxidized after each bed is notable. Other industrial versions of double contact acid plants are  

The starting point for this chapter s calculations is the product gas from a specific 3catalystbed -I- intermediate H2SO4 making sequence (Fig. 19.2). 

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This confirms double contact s S02 oxidation advantage. 

This is called double contact acidmaking because it contacts gas and acid twice, steps (b) and (d). The advantage of double contact acidmaking is that it makes S03 and H2S04(f) more efficiently than single contact acidmaking. 

At the time of writing, there are no industrial triple contact acid plants. These plants would be more complex than their double contact counterparts, so they would have to give a significant S02 oxidation advantage. 

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