Semi-continuous process for alternately producing a sterilizing vapor and regenerating a dilute process solution in a single apparatus

The method of the invention consists in conveying a concentrated aqueous solution of a substance less volatile than water and miscible with the latter into the upper portion of a liquid-vapor exchange column operating at atmospheric pressure and supplied with saturated water vapor at its lower portion, in collecting a dilute aqueous solution of said substance in the lower portion of said column and vapor rich in said substance and sparingly rich in water, at a temperature comprised between about 110 DEG and 150 DEG C, in the upper portion of the said column, said column also alternately functioning to dehydrate, and thereby regenerate said dilute aqueous solution to thereby produce said concentrated aqueous solution.