Process for selectively separating a constituent from a liquid mixture

摘要

517,270. Distilling liquids. MUNEKATA, E. May 20, 1938, No. 15079. [Class 32] A volatile constituent present in admixture or in solution in a liquid system is separated by treating the system with a carrier gas so as to cause preferential evaporation of the volatile constituent and passing the mixture of gas and constituent through an absorption zone in which the constituent is removed from the gas. The vapour pressure of the constituents of the carrier gas common to the system and to the absorption zone is adjusted to be slightly greater in the absorption zone than in contact with the system. The liquid to be treated is placed in the tank 7 and is passed into the evaporating chamber 1 by a pipe 8 by the aid of a pump 6. The unevaporated portion of the liquid flows out through the pipe 8a. The chamber 1 is connected to the separating chamber 2 by two passages 4, 5 provided with a circulating fan 3 for the carrier gas. This gas contains the vapour from the chamber 1 and carries it to the chamber 2 when the vapour is absorbed by an absorbing agent stored in the reservoir 10 and pumped through the chamber 2 via a pipe 11 by a pump 9. In an example, a mixture of 30 per cent. alcohol, 20 per cent. acetic acid and 50 per cent. water at 50 ‹C. is put in the tank 7. The vapour pressure of the liquid is 160mm. of mercury and air is used as the carrier gas mixed with alcohol vapour and steam to raise the total pressure to nearly atmospheric pressure. The acetic acid in the solution, is contained in the carrier gas and is absorbed by an aqueous-alcoholic solution of calcium hydroxide. The precipitated calcium acetate is removed from the absorbing agent and the acetic acid recovered.