Abstract: The Allam Cycle is a transcritical CO2 power cycle that shows great potential to generate low-cost electricity from fossil fuels while producing near-zero air emissions, including CO2. NET Power is currently demonstrating the core cycle by building and commissioning a 50 MWth natural gas-fired power plant in La Porte, Texas. In parallel, a team consisting of the University of North Dakota Energy and Environmental Research Center (EERC), 8 Rivers Capital, the U.S. Department of Energy National Energy Technology Laboratory, ALLETE, Inc., Basin Electric Power Cooperative, and the Lignite Energy Council is working to develop lignite-based Allam Cycle technology. Material corrosion is one of the major issues being studied. A high temperature (up to 750°C), high pressure (up to 300 bar) dynamic corrosion test rig was built at the EERC for testing alloys under various conditions relevant to a lignite-fired Allam Cycle system. In this paper we describe tests of several high nickel alloys to determine their relative performance under conditions representing the low-pressure and high-pressure passages of the primary heat recuperator in conditions similar to those that would be experienced in a lignite fired Allam Cycle power plant. All nickel-based alloys displayed good resistance to oxidation and sulfidation in tests lasting up to 1500 hours. Based on the information obtained to date, none of the nickel-based alloys tested can be rejected for use in this type of system.
Authors: Xijia Lu, Mike McGroddy, Brock Forrest, David Freed, John Kay, Jason Laumb, Joshua Stanislowski, and John Hurley,
Keywords: Allam Cycle, alloy corrosion, high CO2