Demonstration of the Allam Cycle: An Update on the Development Status of a High Efficiency Supercritical Carbon Dioxide Power Process Employing Full Carbon Capture

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The Allam cycle is a novel CO2, oxy-fuel power cycle that utilizes hydrocarbon fuels while inherently capturing approximately 100% of atmospheric emissions, including nearly all CO2 emissions at a cost of electricity that is highly competitive with the best available energy production systems that do not employ CO2 capture. The proprietary system achieves these results through a semi-closed-loop, high-pressure, low-pressure-ratio recuperated Brayton cycle that uses supercritical CO2 as the working fluid, dramatically reducing energy losses compared to steam- and air-based cycles. In conventional cycles, the separation and removal of low concentration combustion derived impurities such as CO2 results in a large additional capital cost and increased parasitic power. As a result, removal in conventional cycles can increase the cost of electricity by 50% to 70% [1]. The compelling economics of the Allam Cycle are driven by high target efficiencies, 59% net for natural gas and 51% net for coal (LHV basis) while inherently capturing nearly 100% CO2 at pipeline pressure with low projected capital and O&M costs. Additionally, for a small reduction in performance the cycle can run substantially water free. The system employs only a single turbine, utilizes a small plant footprint, and requires smaller and fewer components than conventional hydrocarbon fueled systems. The Allam Cycle was first presented at GHGT-11 [2]. Since then, significant progress has been made, including detailed system design, component testing and the construction of a 50 MWth demonstration plant commencing in Q1 2016 and now entering commissioning as of Q4 2016. This paper will review the development status of the Allam Cycle; for the demonstration plant, the construction and commissioning status, schedule, key components, layout, and detailed design; turbine design, manufacturing status; development of a novel dynamic control system and control simulator for the demonstration plant; and other key aspects of the cycle. It will provide an update on the progress of the gasified solid fuel Allam Cycle and then address the overall Allam Cycle commercialization program, benefits and applications, and the expected design of the natural gas 300 MWe commercial NET Power plant projected for 2020.