| abstract |
1,106,736. Liquefaction of gases. LUMMUS CO. 11 Feb., 1966 [16 Feb., 1965], No. 6265/66. Heading F4P. Compressed gas, e.g. methane, air or nitrogen is liquefied by passage through heat exchangers 14, 16, 18, 20, 22, 24 cooled by external refrigerants arranged in cascade formation and is then sub-cooled by passage through an exchanger 26 in a closed nitrogen circuit comprising a multi-stage compressor 74, after coolers 80, 82, 84, exchangers 72, 68 traversed by reverse flowing nitrogen from the warm end of sub-cooler (26), exchangers 70, 66 cooled by an external refrigerant and an expander 64 which exhausts through a line 60 to the cold end of the sub-cooler. Cold liquefied gas at high pressure is flashed to just above atmospheric pressure into a drum 28, product liquid is withdrawn to storage whilst flash vapour is passed through a line 100, exchangers 68, 72, a compressor 106 and refrigerators 40, 46, to assist cooling of propylene and ethylene therein. |