| 摘要 |
1,213,095. Separation of krypton and xenon from air. AIR REDUCTION CO. Inc. 25 April, 1969 [16 May, 1968], No. 21305/69. Heading F4P. Separation of krypton and xenon from a crude liquid oxygen stream 1, Fig. 1, derived from an air rectification column (not shown) is effected by absorbing acetylene in alternating absorbers 9, 10, feeding through a line 21 to the mid-point 22 of a rectification column 23 provided with reflux by a condenser 44, withdraw- ing krypton and xenon-rich liquid oxygen from the sump 24 and returning the major position through a reboiler 28 to the column whilst the remainder of the sump liquid is withdrawn through a line 52, vaporized in alternating heat exchangers 58, 59, heated in exchangers 69, 72, Fig. 2, to about 900‹ F. and passed through a catalyst chamber 74 thereby oxidizing the hydrocarbons, thereafter cooling in exchangers 69, 59 to temperature at which said oxidized impurities mainly carbon dioxide and water are frozen out, passing the so-liquefied krypton and xenon-rich oxygen mixture through filters 100a, 100b and through a line 91 into the middle of a rectification column 92 having a reflux condenser 98, passing uncondensed top gas through a line 102 to the column 23 withdrawing product krypton and xenon-rich liquid from the sump 94 provided with a reboiler 95 through a line 97 and storing it at 125 and finally returning flash vapour from storage through a line 105 to just above the sump of column 92. The feed liquid oxygen in line 1 contains 30 parts per million of krypton and 2 p.p.m. of xenon, the liquid in sump 24 contains 3315 and 220 p.p.m. of krypton and xenon whilst the product contains 92% and 6À7% by volume of krypton and xenon respectively. Reboiler 28 of column 23 is heated by cold compressed gaseous nitrogen admitted through a line 31 and a position of nitrogen so liquefied in reboiler 28 is returned to source through a line 36 whilst the remainder is passed through lines 37, 39 and 40 to the condensers 44, 98 where the nitrogen is vaporized and returned through lines 45, 108, 106 and 30 tothe nitrogen source. The level of liquid in sump 24 is monitored by known electromechanical means 11 which controls a valve 12 in liquid nitrogen return line 36. The level in sump 94 is monitored and the temperature is controlled by an electric heater 95. Also means responsive to liquid level of vapour-condensate in condensers 44, 98 serve to control the liquid nitrogen intake to said condensers.
|
