GB212533A - Improvements in or relating to processes for the separation of gaseous mixtures - Google Patents

Abstract

212,533. Soc. l'Air Liquide, Soc. Anon. pour l'Etude et l'Exploitation des ProcÚdÚs G. Claude. March 10, 1923, [Convention date]. Separating gaseous mixtures by liquefaction.- In the separation of the constituents of gaseous mixtures by liquefaction and rectification by employing expansion with production of external work and utilizing the separated gas or gases to cool a part of the gaseous mixture to liquefy it wholly or in part, this part of the mixture is compressed to a higher pressure than the other part, and the liquid so produced, and in some cases a part of the gas, is expanded by simple throttling to a pressure greater than that of the separating column, the gas so produced being expanded with production of external work, liquefied and separated. The second expansion may be combined in one process with the expansion of the other, low-pressure, portion of the gaseous mixture. In a modification, the throttling may be replaced by an independent expansion of the high pressure gas, which is then delivered to the separating column. In the apparatus shown, air compressed to about ten atmospheres passes through an interchanger B traversed in the opposite direction by the separated oxygen and nitrogen passing through tubes B<1> to the outlets U, S. The cooled compressed air is expanded in a motor D, and the expanded mixture passes through a pipe M<1> to a. coil M in the bottom of a rectifying column N. Here it is cooled by the oxygen collecting in the bottom, and after expansion through a valve O<1> is delivered to the top of the column. The oxygen is withdrawn from the column just above the liquid, in gaseous form, and delivered by a pipe T to the interchanger B. The nitrogen passes from the top of the column to a second exchanger F, and thence is delivered partly to the exchanger B and partly to an outlet Q. Air compressed to say 800 atmospheres is passed through the exchanger F and expanded through a valve G, from which the gas passes to the motor D while the liquid so formed is delivered to the pipe M<1> leading to the separator. In a modification, the valve G is suppressed, the high pressure air passing to an engine or turbine the exhaust of which is delivered to the coil M. Specification 17216/09 is referred to.