Allam Cycle

The Allam cycle, also called the Allam-Fetvedt cycle, is a power generation process that burns a carbonaceous fuel such as natural gas with oxygen and captures the resulting carbon dioxide and water as part of normal operation, rather than needing a separate capture step afterward. It was invented by the English engineer Rodney John Allam together with the American engineers Jeremy Eron Fetvedt and Miles R. Palmer and the American businessman G. William Brown Jr., and MIT Technology Review named it one of its 10 Breakthrough Technologies in 2018. The cycle is a recuperated, high pressure Brayton cycle that burns fuel with oxygen and recycled supercritical carbon dioxide at pressures around 30 megapascals, using the recycled carbon dioxide both to control combustion temperature and to dilute the combustion products; after the working fluid expands through a turbine, the exhaust is cooled, its water removed, and the remaining carbon dioxide compressed and sent back to the combustor. When burning natural gas the cycle has been modeled to reach an efficiency of up to 60 percent on a lower heating value basis, net of all internal power uses including its air separation unit, while producing a high purity, pressurized stream of carbon dioxide ready for storage or use with no extra compression needed.