A method for obtaining a liquid nitrogen product by low-temperature separation of air and air separation plant

摘要

It is a method for obtaining a liquid nitrogen product (lin) by means of low-temperature separation of air (air) in an air separation plant (100) with a distillation columns system (30), the exactly two distillation columns (31, 32), namely a high-pressure column (31) and a low-pressure column (32), each of which is designed as a bath evaporator top condenser (33, 34) with a liquefaction chamber and an evaporation space, is proposed. The method according to the invention comprises, inter alia, a purified feed air stream (b) in a first turbines driven compressor (22) of a first pressure level, which provides an air compressor (12), to a second pressure level, and subsequently, in a second turbines driven compressor (23) of the second to a third pressure level to a compressed air feedstream (c), with the entire air of the compressed air stream (c) then a main heat exchanger (21) is cooled and fed into this. A corresponding air separation unit (100) is likewise subject matter of the invention.