Managing Trace Contaminants in Cryogenic Air Separation
نویسندگان
چکیده
Atmospheric air contains many trace components which are process contaminants or equipment fouling agents in a cryogenic air separation process unit (ASU). Based on the potential problems that they may cause, the trace contaminants are categorized as corrosive, plugging or reactive species. This paper discusses a three step process to manage the trace contaminants as they move through the ASU: identify the hazard, abate the hazard and verify the abatement. Guidelines that contribute to safe and efficient operation of ASU’s are presented and summarized. Focus is placed on the reboiler sump, where high boiling components concentrate in high purity oxygen. The special needs of oxygen vaporizers, where the oxygen is boiled to dryness, are also discussed. Nitrous oxide (N2O) is one of the trace contaminants present in the air and it has received special attention in the past few years. It has a low solubility at cryogenic temperatures, and can be present in sufficient quantities to plug equipment. Various methods used to abate N2O accumulation are discussed, including a novel adsorbent, together with relevant plant operating data.
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