| 摘要 |
1,097,560. Cold separation of gas mixtures. PULLMAN Inc. Feb. 3, 1966 [March 11, 1965], No. 4870/66. Heading F4P. A liquefied gas mixture to be separated in a column 56 into gaseous argon rich nitrogen and liquid methane containing nitrogen is first flashed through a valve 62 into a drum 61, a portion of the liquid fraction so formed is withdrawn through valve-controlled line 63 and is at least partially vaporized in indirect heat exchange at 59 with feed mixture in a line 57 after which at the least partially vaporized liquid fraction is admitted at a point 65 to the column 56 whilst the remainder of the liquid fraction from drum 61 together with the vapour fraction is admitted to a point 67 of column 56 through a line 66. Product liquid methane withdrawn from the base of column 56 is passed through a reflux condenser 116 in the head of the column, and through heat exchangers 11, 24 in which its cold content is recovered and is discharged through a line 124 for use as fuel gas. Argon-rich gas is withdrawn from column 56 through line 69 leading to a column 72 where it is further enriched in argon which is withdrawn in the liquid phase through lines 85, 91 and expanded at a valve 94 into a flash drum 96. Liquid formed therein is at least partially vaporized in indirect heat exchange at 93 with liquid feed in line 91 and fed to a column 84 at a point 101 whilst the remainder of the liquid from drum 96 together with vapour is fed to the column 84 at a point 103. Product argon-rich liquid ' is withdrawn through a line 104 or argon-rich gas may be withdrawn through a line 105. The overhead gaseous fraction consisting mostly of nitrogen is withdrawn through a line 106. The liquid feed mixture for line 57 is derived from purge gas of an ammonia synthesis plant. Compressed feed mixture in a line 10 is cooled in exchanger 11 and condensed ammonia is separated in a drum 12. Residual ammonia vapour is absorbed at 16, feed mixture is cooled at 24, 25 to condensation temperature and fed to a separating drum 27 from which hydrogen-rich vapour is withdrawn through a line 28. A portion is withdrawn as product through a line 31 whilst the rest is exhausted at 29 and added to liquid withdrawn from drum 27 through an expansion valve 34. The combined expanded mixture is fed through a line 35 into a separating drum 26, liquid is expanded through a valve 38 into a flash drum 39 and condensate withdrawn through a line 46 is pressurized by a pump 47 and passed through lines 48, 49, 53 and a reboiler 55 in column 56 to feed line 57. Flash vapour from drum 39 is warmed in exchangers 24, 25 and added to tail gas in line 124. |
