Process for purifying aqueous hydrochloric acid

Claim 1

A PROCESS FOR PURIFYING CONTAMINATED AQUEOUS HYDROCHLORIC ACID, SAID ACID BEING OF AT LEAST 30 PERCENT CONCENTRATION AND CONTAINING DISSOLVED OR SUSPENDED VOLATILE CONTAMINATION, SAID PURIFYING BEING CONDUCTED WITHOUT SUBSTANTIAL LOSS OF ACID CONCENTRATION COMPRISING: (A) INTRODUCING THE CONTAMINATED AQUEOUS HYDROCHLORIC ACID IN A DISTRIBUTED STATE INTO A FIRST PURIFICATION ZONE AT THE TOP THEREOF AND CONDUCTING SAID CONTAMINATED AQUEOUS HYDROCHLORIC ACID DOWNWARDLY THROUGH SAID FIRST ZONE, (B) HEATING SAID ACID AS IT IS CONDUCTED DOWNWARDLY TOWARD THE BASE OF SAID FIRST PURIFICATION ZONE TO EVAPORATE THE CONTAMINATION AND A PORTION OF THE HYDROCHLORIC ACID, WHEREBY THE HYDROGEN CHLORIDE VAPORS AND THE EVAPORTAED CONTAMINATION RISE THROUGH SAID FIRST PURIFICATION ZONE, (C) COLLECTING THE REMAINING PURIFIED HYDROCHLORIC ACID WHICH IS CONDUCTED COMPLETELY THROUGH SAID FIRST PURIFICATION ZONE AT THE BASE THEREOF, (D) PASSING THE HYDROGEN CHLORIDE VAPORS AND THE EVAPORATED CONTAMINATION UPWARDLY FROM SAID FIRST PURIFICATION ZONE INTO THE BASE OF A SECOND PURIFICATION ZONE LOCATED DIRECTLY OVER AND IN COMMUNICATION WITH SAID FIRST PURIFICATION ZONE, WHEREBY THE HYDROGEN CHLORIDE VAPORS AND THE EVAPORATED CONTAMINATION PASS UPWARDLY THROUGH SAID SECOND PURIFICATION ZONE, (E) INTRODUCING A STREAM OF HOT WATER INTO THE TOP OF THE SECOND PURIFICATION ZONE AND PASSING THE STREAM OF WATER COUNTERCURRENTLY TO THE UPWARDLY RISING HYDROGEN CHLORIDE VAPORS AND THE EVAPORATED CONTAMINATION, WHEREBY THE STREAM OF WATER PARTIALLY EVAPORATES TO FORM STEAM WHICH PICKS UP THE EVAPORATED CONTAMINATION WHILE THE HYDROGEN CHLORIDE VAPORS ARE ABSORBED BY THE REMAINING WATER, (F) PASSING THE STEAM AND THE CONTAMINATION OUT OF SAID SECOND PURIFICATION ZONE, AND (G) RETURNING THE WATER CONTAINING THE ABSORBED HYDROGEN CHLORIDE VAPORS TO THE TOP OF THE FIRST PURIFICATION ZONE AND COMBINING THEREIN WITH THE ACID TO PURIFIED.