Production of Ultrahigh-Purity Oxygen: A Distillation Method for the Coproduction of the Heavy Key Component Stream Free of Heavier Impurities

摘要

Use of a side stripper for the coproduction of the heavy key component stream free of undesirable heavier impurities has been suggested. A side stream containing the heavy key component is withdrawn from a column at a location that is sufficiently above the feed such that it is essentially free of the undesired impurities. This side stream is then distilled in a side stripper to remove lighter components. From a given feed, this method is capable of coproducing a significant fraction of the heavy key component with extremely high purities and with minimal additional energy usage. Coproduction of ultrahigh-purity oxygen, containing only ppb level impurities, along with standard-grade oxygen (99.5%) is presented. In comparison with earlier techniques, this method of distillation is simpler and more efficient and uses less equipment while maintaining a high recovery of oxygen from air.