Sulfuric acid production
S + O2 = SO2
SO2 + ½ O2 = SO3
SO3 + H2O =H2SO4
Description: Molten sulfur is oxidized with air in burner. Heat produced is recovered in waste heat boiler. Gas stream containing 7-10% SO2 and 11-14 % O2 preheated by convertor gas and send to first stage reactor . The reacted temp is 500-600o C contained 30% catalyst and convert about 80% of SO2. The converter product exchange heat at 300o C and sent to second stage where yield is increased to 97% at 400-450o C .The product gases are cooled to 150o C by water and air heat exchanger and absorbed in oleum fed at rate to allowed not over 1% rise in acid strength. Final scrubbing is done with lower strength.
DCDA is double conversion double absorption. In sulfuric acid process sulfur is converted two times i.e. SO2 and SO3. SO3 is absorbed in two scrubbers in series.