Process for producing chlorine and recovering substantially pure hydrogen chloride from the hot reaction product

Claim 1

IN THE PROCESS FOR THE SUBSTANTIALLY COMPLETE CONVERSION OF HYDROGEN CHLORIDE TO CHLORINE IN A PROCESS WHEREIN HYDROGEN CHLORIDE IS REACTED WITH AIR IN THE PRESENCE OF A CATALYST CONSISTING ESSENTIALLY OF COPPER HALIDE IN ADMIXTURE WITH A LANTHANIDE HALIDE AND POTASSIUM HALIDE AT A TEMPERATURE OF FROM ABOUT 300 TO ABOUT 600*C., THEREBY FORMING A REACTION MIXTURE COMPRISING HYDROGEN CHLORIDE IN ADMIXTURE WITH WATER VAPOR AND CHLORINE IN A REACTION ZONE, THE COMBINATION OF STEPS CONSISTING ESSENTIALLY OF: QUENCHING SAID REACTION MIXTURE IN A QUENCHING ZONE TO A TEMPERATURE IN THE RANGE OF FROM ABOUT 40* TO ABOUT 150*C. WITH HYDROCHLORIC ACID OBTAINED WITHIN THE SYSTEM, SUBJECTING THE RESULTING QUENCHED REACTION MIXTURE TO COUNTERCURRENT DIRECT CONTACT WITH LIQUID SOLVENT FOR HYDROGEN CHLORIDE GAS IN SAID EXTRACTION ZONE, THEREBY SEPARATING A VAPOR OVERHEAD RAFFINATE FRACTION COMPRISING WATER VAPOR AND CHLORINE FROM A LIQUID BOTTOM EXTRACT FRACTION COMPRISING ENRICHED HYDROCHLORIC ACID IN THE BOTTOM OF SAID EXTRACTION ZONE, INTRODUCING LIQUID DILUTE HYDROCHLORIC ACID EMANATING FROM WITHIN THE SYSTEM INTO SAID EXTRACTION ZONE AT AN INTERMEDIATE POINT THEREOF AS SAID SOLVENT FOR HYDROGEN CHLORIDE GAS, INTRODUCING LIQUID WATER AS SUPPLEMENTARY SOLVENT FOR HYDROGEN CHLORIDE GAS INTO SAID EXTRACTION ZONE AT A POINT NEAR THE WITHDRAWAL OF SAID VAPOR OVERHEAD RAFFINATE FRACTION THEREFROM, PASSING A PART OF SAID LIQUID BOTTOM EXTRACT FRACTION FROM SAID EXTRACTION ZONE INTO SAID QUENCHING ZONE TO BE USED THEREIN AS SAID HYDROCHLORIC ACID EMANATING FROM WITHIN THE SYSTEM, PASSING THE REMAINDER OF SAID BOTTOM EXTRACT FRACTION FROM SAID EXTRACTION ZONE INTO A DISTILLATION ZONE, DISTILLING HYDROGEN CHLORIDE FREE OF ANY SUBSTANTIAL AMOUNT OF WATER FROM STILL BOTTOMS CONSISTING ESSENTIALLY OF DILUTE HYDROCHLORIC ACID APPROXIMATING THE HYDROGEN CHLORIDEWATER AZEOTROPE IN SAID DISTILLATION ZONE, PASSING SAID LIQUID STILL BOTTOMS FROM SAID DISTILLATION ZONE INTO SAID EXTRACTION ZONE AT SAID INTERMEDIATE POINT THEREOF TO BE USED THEREIN AS SAID DILUTE HYDROCHLORIC ACID EMANATING FROM WITHIN THE SYSTEM, SEPARATING CHLORINE FROM SAID VAPOR OVERHEAD FRACTION SEAPARATED IN SAID EXTRACTION ZONE, CONTROLLING THE TEMPERATURE AT WHICH SAID DILUTE HYDROCHLORIC ACID AND WATER SOLVENT STREAMS ARE INTRODUCED INTO SAID EXTRACTION ZONE TO MAINTAIN THE TOTAL AMOUNT OF WATER WITHDRAWN OVERHEAD FROM SAID EXTRACTION ZONE AND IN THE UNCONDENSED OVERHEAD ELIMINATED FROM SAID DISTILLATION ZONE SUBSTANTIALLY EQUAL TO THE TOTAL AMOUNT OF WATER INTRODUCED INTO SAID QUENCHING ZONE AND AS SUPPLEMENTARY SOLVENT INTO SAID EXTRACTION ZONE, AND RECYCLING UNCONDENSED OVERHEAD FROM SAID DISTILLATION ZONE TO SAID REACTION ZONE.