초록 ▼

A first flow of air is compressed in a first air compressor associated with a gas turbine and is purified in an adsorptive purification unit which separates water vapour and carbon dioxide from the air. The purified first flow of air is further compressed to a pressure at least 5 bar higher than tha

A first flow of air is compressed in a first air compressor associated with a gas turbine and is purified in an adsorptive purification unit which separates water vapour and carbon dioxide from the air. The purified first flow of air is further compressed to a pressure at least 5 bar higher than that at which it is purified in a second air compressor whose outlet pressure is independent of fluctuations in the power output of the gas turbine, is cooled in a main heat exchanger, is passed through an expansion valve, and is introduced into a higher pressure rectification column. A second flow of air is compressed in a third air compressor which is independent of the gas turbine. The compressed second flow of air is purified in an adsorptive purification unit by the separation of water vapour and carbon dioxide therefrom. The purified second flow of air is cooled in the main heat exchanger and is introduced into the higher pressure rectification column. The air flows are rectified in the higher pressure rectification column and an associated lower pressure rectification column operating at pressures above 2 bar. A nitrogen product is withdrawn from the top of the lower pressure rectification column and a liquid oxygen product from the bottom thereof. The liquid oxygen is revised in pressure to at least 25 bar by a pump and is warmed to ambient temperature in the main heat exchanger.

대표청구항 ▼

In a method of separating air comprising: a) taking a first flow of air from a first air compressor associated with a gas turbine; b) purifying said first flow of air by separating water vapour and carbon dioxide therefrom; c) further compressing at least part of the first air flow in a second air c

In a method of separating air comprising: a) taking a first flow of air from a first air compressor associated with a gas turbine; b) purifying said first flow of air by separating water vapour and carbon dioxide therefrom; c) further compressing at least part of the first air flow in a second air compressor; d) heat exchanging at least part of the further compressed and purified first air flow with a stream of pressurised oxygen taken from a lower pressure rectification column in liquid state; e) reducing the pressure of at least part of the heat exchanged first air flow and introducing it into a higher pressure rectification column; f) compressing a second flow of air in a third air compressor which is independent of said gas turbine; g) purifying said second flow of air by separating water vapour and carbon dioxide therefrom, cooling the second flow of air, and introducing the cooled second flow of air into the higher pressure rectification column; h) rectifying the air flows in the higher and lower pressure rectification columns; and i) withdrawing a gaseous nitrogen stream from the lower pressure rectification column; the improvement comprising: i) operating the second air compressor with an outlet pressure independent of fluctuations in the power output of the gas turbine; ii) purifying of the first air flow at a pressure at least about 5 bar less than that at which the said part of the first air flow leaves the second compressor; iii) operating the lower pressure rectification column at pressures in excess of about 2 bar; iv) pressurising the liquid oxygen to a pressure of at least about 25 bar.