Patent ID: 7143606
Filing Date: 2006-12-05
Classification: F25J

Abstract:
1. An integrated process for the separation of air by cryogenic distillation and liquefaction of natural gas in which at least part of the refrigeration required to liquefy the natural gas is derived from at least one cryogenic air distillation plant comprising a main heat exchanger and distillation columns, wherein the natural gas liquefies by indirect heat exchange in a heat exchanger with a cold fluid, the cold fluid being sent to the heat exchanger at least partially in liquid form and undergoing at least a partial vaporization in the heat exchanger; wherein the natural gas is liquefied within the main heat exchanger of the cryogenic air distillation plant, in which feed air for the cryogenic air distillation plant is cooled to a temperature suitable for distillation and the cold fluid is at least one liquid stream, enriched in at least one of oxygen, nitrogen and argon with respect to air, which vaporises in the main heat exchanger; wherein all the air to be separated in the cryogenic air distillation plant is cooled in the main heat exchanger, and wherein the natural gas is liquefied by heat exchange in an additional heat exchanger other than the main heat exchanger with at least one cold fluid which has previously been cooled by a vaporising liquid in the main heat exchanger of at least one air distillation plant.