Indirect fired gas turbine integrated with an air separation unit

Oxygen is produced by compressing air (1) to provide a first and a second pressurized air stream (5,7), separating the first pressurized air stream (5) into an oxygen-rich product stream (17) and a nitrogen-rich byproduct stream (11), which is heated by indirect heat exchange (21) with a hot process stream (23) and is work expanded in a gas turbine expander (27). The second pressurized air stream (7), separately or in combination with the nitrogen-rich byproduct stream (11), also is heated by indirect heat exchange (21) with a hot process stream (23) and work expanded in a gas turbine expander (27). At least a portion of the expander(s) shaft work is utilized for the air compression step (3). Fuel (35) is combusted with the air-containing expander discharge stream (29) to provide a hot process stream (23) for said indirect heat exchange(s). The use of this integrated indirectly-fired gas turbine to provide pressurized feed air for the air separation system improves the availability and reliability of the integrated system compared with conventional directly-fired gas turbine systems.