GB893057A - Improvements in or relating to low temperature gas mixture separation processes - Google Patents

Abstract

893,057. Cold separation of gas mixtures. UNITED KINGDOM ATOMIC ENERGY AUTHORITY. Nov. 12, 1958 [Nov. 25, 1957], No. 36616/57. Class 8(2) In a process for separating deuterium from a crude hydrogen mixture by rectification following freezing out nitrogen and carbon monoxide in a line 2, Fig. 2a, of aheat exchanger 1 having counterflowing pure hydrogen line 3 or in a line 5 of a heat exchanger 4 having a counterflow pure hydrogen line 6 in the event of line 2 of exchanger 1 being derimed, deriming is effected by passing pure outflow hydrogen through the congested line of the offstream exchanger in the direction of feed and allowing said line to warm up to the temperature at which feed mixture normally enters the line. In operation and assuming exchanger 1 to be or stream and exchanger 4 to be in process of being derimed, crude mixture at 51‹K enters line A, traverses an open valve 9, line 2, open valves 17, 18 and is discharged at 22À5‹K through a line B to the rectification column from which outflow hydrogen passes into a line D at 21À5‹K, through an open valve 19, the line 3, a valve 8 at 50‹K leading to a discharge line C. This outflow hydrogen is warmed by heat from a turbo-expander (not shown), and is fed to a line K and through a valve 15 to the warm end of line 5 to effect vaporization of congealed nitrogen and carbon monoxide, and the contaminated outflow hydrogen traverses a valve 20 and is discharged through a line J. Immediately prior to switching the feed mixture from line 2 to the derimed line 4 the latter is cooled by a reverse flow of cold purified feed mixture leaving line 2 and being directed through a valve 21, Fig. 2b (the valve 18 being closed), the line 5, a valve 14 and a line leading to an open valve 22 and to the line B. Line 5 having been cooled, feed mixture is directed therethrough by opening valves 13, 18, Fig. 2C, and closing valves 9, 22 whilst outflow hydrogen is directed through line 6 in counterflow to the feed mixture by opening valves 23, 12 and closing valves 19, 8. The so-wormed outflow hydrogen leaves by line C and after having been further warmed in the turbo expander enters line K and is directed through line 2 by opening valves 11, 16 and closing valves 17, 20; the contaminated outflow hydrogen leaving through line J. Specification 869,412 is referred to.