Hydrochloric acid recovery

Claim 1

A PROCESS FOR THE MANUFACTURE OF HYDROCHLORIC ACID WHICH COMPRISES SUPPLYING WATER AT A TEMPERATURE SUBSTANTIALLY BELOW 100* C., TO THE UPPER PORTION OF AN UNCOOLED ABSORPTION TOWER, SUPPLY A GAS RICH IN HYDROGEN CHLORIDE TO THE LOWER PORTION OF THE ABSORPTION TOWER AT A TEMPERATURE SUBSTANTIALLY BELOW 90* C., PASSING THE HYDROGEN CHLORIDE CONTAINING GAS UPWARDLY THROUGH THE ABSORPTION TOWER COUNTERCURRENT TO THE FLOW OF WATER THERETHROUGH WHEREBY THE HYDROGEN CHLORIDE GAS IS ABSORBED BY THE WATER, CONTROLLING THE RATE OF FLOW OF THE WATER, THE RATE OF FLOW OF SAID GAS, AND THE TEMPERATURES THEREOF SO AS TO MAINTAIN THE TEMPERATURE WITHIN THE TOWER AT THE ENTRANCE POINT OF THE GAS SUBSTANTIALLY BELOW 90* C. AND THE STRENGTH OF THE ACID OBTAINED AT LEAST ABOUT 20* BE. (ABOUT 32% ALLOWING THE HEAT OF ABSORPTION OF THE HYDROGEN CHLORIDE IN THE WATER TO EVAPORATE A PORTION OF THE WATER IN THE TOWER, APPLYING PARTIAL VACUUM TO EVAPORATE ADDITIONAL WATER AND TO WITHDRAW AN AMOUNT OF WATER VAPOR FROM THE SUPPER PORTION OF THE TOWER WHICH CONTAINS AS LATENT HEAT OF VAPORIZATION AN AMOUNT OF HEAT WHICH IS A SUBSTANTIAL PROPORTION OF THE HEAT OF ABSORPTION EVOLVED IN THE TOWER, AND WITHDRAWING FROM THE BOTTOM OF THE TOWER AN ACID WITH A CONCENTRATION OF AT LEAST ABOUT 32% BY WEIGHT OF HYDROGEN CHLORIDE.