A novel cryogenic air separation process based on self-heat recuperation

Abstract

In this paper, a novel cryogenic air separation process that reduces energy consumption by self-heat recuperation is proposed. In the proposed cryogenic air separation process, heat from the top vapor stream of the column is recuperated and exchanged with heat in the bottom liquid and feed streams, using self-heat recuperation technology. As a result, not only the latent heat but also the sensible heat of the process stream is circulated in the process. Furthermore, the pressure in the column can be decreased compared with the high pressure part of a conventional cryogenic air separation system, in which high and low pressure columns are combined to exchange nitrogen latent heat with oxygen latent heat. Thus, the energy input to the main compressor located before the column can be dramatically reduced. A simulation demonstrated that the energy consumption of the proposed cryogenic air separation process with self-heat recuperation decreased by more than 36% compared with the conventional cryogenic air separation process, when producing 99.99 mol% oxygen from air.