A new high-pressure catalytic Partial oxidation reactor was developed for high-pressure production of synthesis gas from natural gas and pure oxygen, and the integration of the new reactor with the gas to liquids process was investigated, The experimental work was performed at Praxair's laboratory, process design and economic estimates were performed by Foster Wheeler, and theoretical simulations were preformed by University of Delaware. The reactor system was based oil a millisecond contact time mixer capable of delivering a fuel-oxygen mixture to the catalyst without Onset of homogeneous reactions. Significant differences were observed between high- and low-pressure operation. With proper mixer and catalyst bed design the system was able to operate stably at pressures up to 18 bar with performance comparable to low-pressure operation. Process economic analysis predicted a small economic advantage for a catalytic partial oxidation reactor compared to conventional technology.