Low SO{HD 2 {B emission sulfuric acid process form sulfur and oxygen

Claim 1

A PROCESS FOR THE PRODUCTION OF SULFURIC ACID FROM SULFUR AND AN OXYGEN-CONTAINING GAS CONTAINING AT LEAST 40% BY VOLUME MOLECULAR OXYGEN COMPRISING REACTING THE SULFUR WITH SAID GAS AT ABOUT 900-3*C., TO FROM AN SO2-CONTAINING COMBUSTION GAS, OXIDIZING SAID COMBUSTION GAS WITH OXYGEN IN A MAIN CONTACT OXIDATION STAGE TO FORM AN SO3-CONTAINING CONTACT GAS, ABSORBING SAID SULFUR TRIOXIDE IN A MAIN ABSORPTIONN STEP TO FORM A RESIDUAL SO3-LEAN GAS, BRANCHING SAID SO3-LEAN GAS INTO PORTIONS THEREOF, HEATING AND PASSING A FIRST PORTION THEREOF INTO SAID MAIN CONTACT STAGE IN ADMIXTURE WITH SAID SO2-CONTAINING, COMBUSTION GAS AN OXYGEN, HEATING A SECOND PORTION OF SAID SO3-LEAN GAS TO A TEMPERATURE LESS THAN THAT OF SAID FIRST PORTION AND PASSING ONLY HEATED SECOND PORTION OF SO3- LEAN GAS TO A POST-CONTACT OXIDATION STAGE TO CONVERT RESIDUAL SO2 TO SO3, AND SUBJECTING RESULTANT SO2 DEPLETED GAS TO A SUPPLEMENTAL POST-CONTACT ABSORPTION STEP, SAID POST-CONTACT OXIDATION STAGE AND SUPPLEMENTAL POST-CONTACT ABSORPTION STEPS BEING CONDUCTED IN EQUIPMENT SIMILAR TO, BUT SEPARATE AND DISTINCT FROM, AND PHYSICALLY SMALLER THAN COMPARABLE EQUIPMENT PROVIDED FOR THE MAIN CONTACT OXIDATION STAGE AND THE MAIN ABSORPTION STEP RESPECTIVELY.