Recovery of hydrogen halides

Claim 1

A PROCESS FOR RECOVERING A SUBSTANTIALLY ANHYDROUS HYDROGEN HALIDE SELECTED FROM THE GROUP CONSISTING OF HYDROGEN CHLORIDE AND HYDROGEN BROMIDE FROM A GAS STREAM CONSISTING ESSENTIALLY OF PERMANENT GAS CARRYING A SUBSTANTIAL AMOUNT OF WATER VAPOR AS WELL AS SAID HYDROGEN HALIDE, IN A PROPORTION MORE CONCENTRATED THAN AZEOTROPIC WITH RESPECT TO THE HYDROGEN HALIDE, SAID PROCESS BEING CHARACTERIZED BY THE STEPS OF WASHING SAID STREAM IN COUNTERCURRENT WITH A WATER SOLUTION OF SAID HYDROGEN HALIDE HAVING A CONCENTRATIN LESS THAN AZEOTROPIC WITH RESPECT TO THE HYDROGEN HALIDE, WHICH WATER SOLUTION AS IT ENTERS THE WASHING IS ABOVE 50*C. TO CAUSE THE GAS STREAM LEAVING THE WASHING TO CARRY WATER VAPOR AND A RELATIVELY SMALL CONCENTRATION OF HYDROGEN HALIDE, THE WASHING LIQUID BEING COOLED AS IT GOES THROUG THE WASHING SO THAT AS IT EMERGES FROM THE WASHING IT ABSORBS HYDROGEN HALIDE FROM THE ENTERING STREAM AND REACHES A HYDROGEN HALIDE CONCENTRATION GREATER THAN AZEOTROPIC, WORKING UP SAID EMERGING ACID BY BOILING TO OBTAIN HYDROGEN HALIDE OF 100% STRENGTH AND AN ESSENTIALLY AZEOTROPIC ACID, COOLING THE WASHED GAS STREAM IN A MANNER SUCH THAT SUBSTANTIALY ALL ITS HYDROGEN HALIDE IS CONDENSED TOGETHER WITH PART OF ITS WATER VAPOR TO FORM AN AQUEOUS HYDROHALIDE SOLUTION LESS CONCENTRATED THAN AZEOTROPIC WITH RESPECT TO HYDROGEN HALIDE AND TO LEAVE THE RESIDUAL GAS WITH THE EXCESS OF WATER VAPOR AND LESS THAN ABOUT 0.1% BY VOLUME OF HYDROGEN HALIDE.