Abstract: A system comprising a compressor (10) having an inlet stream (25) and an outlet stream (26), a pre-heater (12) having a process inlet stream (29) and a process outlet stream (31), a catalytic combustor (13) having an inlet stream (32) and an outlet stream (33) and containing an catalyst, and a turbine (14) having an inlet stream (34) and an outlet stream (35), wherein, the outlet stream (26) of the compressor(10) is connected to the process inlet stream (29) of the pre-heater (12), the process outlet stream (31) of the pre-heater (12) is connected to the inlet stream (32) of the catalytic combustor (13). The outlet stream (33) of the catalytic combustor (13) is connected to the inlet stream (34) of the turbine (14). During operation of the system, the inlet stream (25) of the compressor (10) has a substantially constant and low concentration of fuel.