Project ForgeChemical Technology
Inorganic Chemical Industries
GATE 2013
Medium
In the manufacture of sulphuric acid by the contact process, the catalytic oxidation of SO2 is carried out in multiple stages mainly to
- Aincrease the reaction rate by providing inter-stage heating
- Bincrease the overall conversion by providing inter-stage heating
- increase the overall conversion by providing inter-stage cooling
- Ddecrease the overall conversion by removing sulphur trioxide between stages
Explanation
SO2 oxidation to SO3 is exothermic and equilibrium-limited, so conversion is favored at LOWER temperature even though rate is favored at higher temperature. Multi-stage operation with inter-stage cooling removes heat between beds, keeping the reaction closer to the more favorable (lower-temperature) equilibrium at each stage and boosting overall conversion.
Source: GATE CH 2013 (2013)
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