Air separation process with single distillation column for combined gas turbine system

A process for separating high purity oxygen from air in a single pressure distillation column comprising the steps of:

• (a) compressing an air feed stream wherein the compressor is powered by a gas turbine,
• (b) cooling the air feed stream in a reversing heat exchanger against a nitrogen waste stream from said column and an oxygen product stream,
• (c) separating a side air feed stream from a remaining air feed stream and passing the side stream back through the heat exchanger to provide a temperature unbalance to preclude carbon dioxide and water buildup in said exchanger,
• (d) expanding and cooling the side stream in a turbine before introducing said stream into an intermediate point of said column,
• (e) heat exchanging the remaining air feed stream with the liquid phase of the bottom of said column to condense said stream and reboil said liquid,
• (f) further heat exchanging the remaining air feed stream against the overhead product stream of said column before introducing said feed stream as reflux into the top of said column,
• (g) removing, at pressure, a nitrogen waste stream containing a combustible level of oxygen from the top of said column as the overhead product stream of step (f),
• (h) combusting said pressurized nitrogen waste stream with a fuel to provide a hot pressurized gas feed to said gas turbine of step (a),
• (i) removing a high purity oxygen product stream from the bottom of said column and pressurizing the same by a compressor driven by a steam turbine wherein said steam turbine is provided with steam by a cyclic heat exchange of the steam with the exhaust of the gas turbine.