Direct-fired super-critical carbon dioxide (sCO2) power cycles, are a potential method for efficiently capturing nearly all of the CO2 emissions from burning fossil fuels. Direct-fired sCO2 cycles require a very high degree of recuperation, which in turn means that the inlet temperature to the combustor is significantly higher than would typically be seen in a similar gas turbine combustors. Previous efforts have shown that combustor inlet temperatures of around 700 °C are to be expected for a cycle with around 1200 °C combustor exit temperatures . This high inlet temperature means that bypass gasses are extremely hot, which poses some difficulties for the design of the combustion system, especially thermal management of the combustor liner and injectors in the 200 bar sCO2 environment.
The project team led by Southwest Research Institute (SwRI) is in the process of building a 1 MW scale direct-fired combustor. This paper will detail some of the design challenges and obstacles associated with designing a direct-fired sCO2 combustor. These obstacles include thermal management of fuel and oxygen streams, oxygen safety, and combustor cooling. This paper will focus on many of the design questions necessary for the design of a direct-fired sCO2 combustor. This work presents computational modeling details of the actual 1 MW geometry currently being built.