Patent ID: 6170291
Filing Date: 2001-01-09
Classification: F25J,Y10S

Abstract:
A method of separating air by rectification, including:compressing the air to a first pressure;without further compression, cooling in a main heat exchanger a first flow of the compressed air to a temperature suitable for its separation by rectification and introducing the first flow into a higher pressure column of a double rectification column comprising, in addition to the higher pressure column, a lower pressure column, in which a bottom oxygen fraction having an oxygen content in the range of about 50 to about 96 mole percent is formed;expanding with the performance of external work a second flow of the compressed air; andintroducing the expanded second flow into the lower pressure rectification column, and taking an impure oxygen product from the said bottom fraction the external work being the generation of electrical power;the double rectification column additionally including a condenser-reboiler placing the higher pressure column in heat exchange relationship with the lower pressure column, and the expansion of the second flow being performed without further compression of the second flow upstream thereof.