Dual Purity Oxygen from an Air Separation Unit
Publication Date: 2003-Sep-12
The IP.com Prior Art Database
In a dual column thermally integrated cryogenic air separation unit (ASU), purified oxygen is obtained from the sump of low pressure column with single or multiple reboilers. For the fixed boil-up in the lower pressure column, a larger quantity of low purity oxygen (lower than 98%) product can be obtained compared to the high purity product (98% and higher). Thus, the oxygen recovery for low purity product is greater than that for the high purity product. The given boil-up can also be utilized to co-produce high purity oxygen product from the sump of lower pressure column with a single reboiler. It was observed that without any significant penalty to the recovery, a fraction of high purity oxygen product can be produced from the sump of lower pressure column with a single reboiler and the low purity oxygen product can be obtained from the section above the sump. Up to 40% of the product can be obtained as high purity oxygen stream without any significant penalty to the recovery, and beyond 40% the high purity product can be obtained with a small penalty of reduced oxygen recovery.