Scaling and burner design concepts of a staged-pressurized oxy-combustion boiler

Oxy-coal combustion is a promising technology for carbon capture, utilization and storage (CCUS). One of the primary limitations of oxy-coal combustion is the large efficiency penalty compared to air-fired combustion without carbon capture. The staged, pressurized oxy-combustion (SPOC) process significantly reduces this efficiency penalty by reducing the amount of flue gas recycle, and by capturing and utilizing the latent heat of condensation of flue gas moisture. The SPOC power plant consists of multiple pressurized boilers connected in series. This staged combustion approach allows for significant reduction of flue gas recycle. In this work, the scaling and the burner and boiler design concepts are presented and evaluated using CFD simulations. Since for a low flue gas recycle system the local temperatures could be very high, the primary objective during design optimization is to control the heat flux to the boiler tubes. An analysis of the radiation heat transfer in a SPOC boiler is presented to demonstrate that radiative heat flux can be well controlled, even in the case of extremely high flame temperature, due to the high optical thickness of the medium.