AbstractThe Controlled Freeze Zone™ technology removes CO2 and H2S from natural gas in a single step cryogenic distillation process. Removal and management of acid gas impurities from natural gas pose significant challenges in developing sour gas fields. In many cases CFZ™ is capable of processing sour gases with a wide range of CO2 and H2S compositions at a lower cost than conventional technologies. The acidic components are removed as a high pressure liquid that can be injected into reservoirs for geosequestration or, when of suitable composition, to improve oil recovery. In either case, sulfur production from H2S and release of CO2 to the atmosphere can be eliminated.CFZ™ technology was successfully demonstrated through earlier pilot plant operations. Currently, ExxonMobil Upstream Research Company is advancing CFZ™ to large scale commercial readiness through a commercial demonstration plant in Wyoming, USA. By building the commercial demonstration plant at ExxonMobil’s world-class Shute Creek gas treating and acid gas injection facility, integration of CFZ™ with acid gas injection, will also be demonstrated when the unit is operated in 2010–2011.