Process for treating the effluent gas obtained by the oxidation of a hydrogen halide gas

Claim 1

IN A PROCESS WHEREIN THE CHLORINE GS IS PRODUCED BY THE OXIDATION OF A HYDROGEN CHLORIDE IN THE PRESENCE OF AN OXIDATION CATALYST AND AN EFFLUENT GAS CONTAINING WATER, HYDROGEN CHLORIDE AND CHLORINE IS PRODUCED, THE IMPROVEMENT FOR TREATING THE EFFLUENT WHICH COMRPSIES: COUNTERCURRENTLY CONTACTING THE EFFLUENT INTRODUCED INTO THE LOWER PORTION OF A DRYING ZONE PACKED WITH ACIDRESISTANT CONTACT MATERIAL WITH AN AQUEOUS SOLUTION OF SULFURIC ACID, COOLING AND DRYING THE EFFLUENT IN THE DRYING ZONE UNDER ADIABATIC CONDITIONS TO A WATER DEW POINT OF LESS THAN -30*F., RECOVERING DRIED EFFLUENT GAS FROM THE DRYING ZONE, PASSING SULFURIC ACID HAVING AN INCREASED HEAT CONTENT AND CONTAINING SORBED WATER TO A DEHYDRATING ZONE, FLASHING AT LEAST THE SORBED WATER FROM THE SULFURIC ACID IN THE DEHYDRATION ZONE UNDER ADIABATIC CONDITIONS AND REDUCED PRESSURE TO RESTORE AT LEAST THE ORIGINAL CONCENTRATION OF THE ACID, COOLING AT LEAST A PORTION OF THE RECONCENTRATED SULFURIC ACID TO A TEMPERATURE BELOW THE TEMPERATURE OF THE DRIED EFFLUENT LEAVING THE DRYING ZONE AND RECYCLING SAID COOLED, DEHYDRATED SULFURIC ACID TO THE UPPER PORTION OF SAID DRYING ZONE, RECOVERING CHLORINE FROM THE DRIED EFFLUENT REMOVED FROM THE UPPER PORTION OF THE DRYING ZONE BY PRESSURIZING THE EFFLUENT AND CONDENSING THE CHLORINE PRODUCT FROM THE UNCONDENSED HYDROGEN CHLORIDE IN THE EFFLUENT, RECYCLING UNCONDENSED HYDROGEN CHLORIDE TO THE OXIDATION ZONE AS PART OF THE FEED THERETO AND RECOVERING CHLORINE AS THE PRODUCT OF THE PROCESS.