Assessment of the potential benefits and constraints of a hybrid solar receiver and combustor operated in the MILD combustion regime

A novel configuration of a Hybrid Solar Receiver and Combustor (HSRC) operated in the Moderate and Intense Low oxygen Dilution (MILD) combustion regime, termed the MILD HSRC is reported. This combustion regime is chosen because of its potential to lower NOx emissions, while increasing the magnitude and uniformity of heat transfer relative to alternative combustion systems, but has not previously been assessed with the HSRC concept. An analytical model is used to identify configurations of the MILD HSRC that achieve the conditions required for MILD combustion. The preferred configuration was then incorporated into a multiple time-step, piecewise-continuous model to evaluate the potential savings in fuel and hence, overall Levelized Cost of Electricity (LCOE) for the MILD HSRC in an electrical power plant. This revealed that there is potential to reduce fuel consumption and LCOE by up to 41% and 4% respectively, relative to the HSRC operating with conventional combustion for a receiver size of 30MWth. The reduction in LCOE increases up to 6% for a receiver size of 100MWth due to economies of scale. This justifies further work to develop detailed designs and evaluate specific technical and economic performance through demonstration and scale-up.