A new synthesis gas production process based on partial oxidation (POX) of natural gas is investigated. Synthesis gas and mechanical power are generated in a plant that integrates a POX reactor, a synthesis gas turbine and an air separation unit. The synthesis gas is expanded in the turbine which runs the air separation unit. By means of an exergy analysis, it is shown that the synthesis gas turbine is a very efficient way of synthesis gas heat recovery. When compared with a conventional system (which uses a heat recovery steam generator), the new plant delivers 10 times more power, reduces with 26.4% the exergy losses and has an increased efficiency with 3.7%.