Abstract: There are provided systems and methods for using partial oxidation to produce an end product from hydrocarbon gases, such as flare gas. There are provided methods and systems to minimize the amount of compression work needed for an air breathing engine reformer in a gas-to-liquid system and method by one or more of: (a) reducing the amount of nitrogen; (b) increasing back-pressure of the engine reformer from standard 1 or 2 bar, to up to 5 bar; (c) use of a turbo-expander to recover much of the compression work, thus lowering the cost, among other efficiencies, to operate a plant; and (d) utilizing an intensified synthesis loop to achieve acceptable methanol synthesis at lower overall pressure. In an embodiment, the end product is methanol.