High pressure combustion turbine and air separation system integration

In an integrated combustion turbine/air separation process which includes compressing air in a combustion turbine air compressor (105), combusting a first portion (7) of the resulting compressed air (6) with a fuel (1) in a combustor (101) to form hot combustion products, expanding the hot combustion products (9) in a hot gas expander (103) which drives the combustion turbine air compressor (105) and optionally an electric generator (107), cooling a second portion (11) of the compressed air, removing impurities from the resulting cooled compressed air (14), and separating the resulting purified compressed air (15) into one or more products, the separation of the purified compressed air (15) is carried out by a method which comprises:

• (a) cooling the purified compressed air (15), work expanding a first portion (17) of the resulting cooled air, and introducing the resulting cooled work-expanded air (19) into a lower pressure distillation column (119);
• (b) further cooling a second portion (21) of the resulting cooled air, reducing the pressure of the further cooled air (22), and introducing the resulting reduced-pressure cooled air (23) into a higher pressure distillation column (123);
• (c) withdrawing an oxygen-enriched liquid bottoms stream (33) from the higher pressure distillation column (123), cooling and reducing the pressure of the stream, and introducing the resulting cooled reduced-pressure stream into the lower pressure distillation column (119);
• and
• (d) withdrawing a nitrogen-rich product (35) from the lower pressure distillation column (119).