Carbon dioxide-tolerant nitrogen rejection reduces costs

A. Farooq, A. Finn, A. Hosainy and G. Johnson, Costain Natural Resources, Manchester, UK For commercial-scale nitrogen (N2) removal, cryogenic distillation is the only cost-effective technology. Cryogenic N2 rejection produces a high-purity N2 waste stream, which can be vented to the atmosphere and which achieves very high hydrocarbon recovery with low power consumption. Cryogenic N2-rejection processes that employ a pre-separation distillation unit can handle up to 60 times as much feed gas CO2 as processes that do not use pre-separation. A new process, achieved through the modification of an established cryogenic N2-rejection process, allows up to approximately 2 mol% CO2 content in the