UTILIZATION OF NITROGEN-ENRICHED STREAMS PRODUCED IN AIR SEPARATION UNITS COMPRISING SPLIT-CORE MAIN HEAT EXCHANGERS

摘要

Split-core main heat exchangers are employed to warm up product streams generated in an air rectification unit (43) against 1) a main feed air stream (10a) in the low pressure heat exchanger (31) and 2) at least one boosted pressure air stream (11) in the high pressure heat exchanger (32). Because the boosted pressure air stream (11) is at a higher pressure and temperature than the main feed air stream (10a), after separate heat exchange in the split main heat exchangers, the subsidiary waste nitrogen stream (135) exiting the high pressure heat exchanger (32) is also warmer than the subsidiary waste nitrogen stream (134) exiting the low pressure heat exchanger (31). The warmer waste nitrogen stream (138) is fed into the air purification unit (3) for regeneration purposes and the cooler waste nitrogen stream (137) is introduced into the nitrogen water tower (4) to perform cooling duty. The two subsidiary waste nitrogen streams (134, 135) are also connected on the warm side of the main heat exchangers to allow flexible distribution of the flow.