Oxy-fuel combustion for use with coal to produce CO2 in an enhanced oil recovery application was evaluated by B&W initially in 1979 at the request of a major oil company. Beginning in 2001 and with the support of the U.S. Department of Energy (DOE) and others, B&W has worked to develop an advanced carbon capture technology for electric power generation plants. This oxy-fuel combustion process can be applicable to coal, natural gas, or oil-fired units.
In the oxy-fuel process, boiler combustion air is replaced with nearly pure oxygen from an air separation unit (ASU). Nitrogen that would normally be conveyed with the air through conventional air-fuel firing is excluded. Instead, a portion of the CO2-rich flue gas is recirculated to a conventional pulverizer/burner system, substituting CO2 for the nitrogen in the furnace. Oxy-combustion creates a flue gas that is primarily CO2, rather than nitrogen, and includes other products of combustion (although greatly reduced nitrogen oxides [NOx]). The non-recirculated flue gas leaving the boiler is cleaned using conventional particulate and sulfur removal systems and sent to the compression purification unit (CPU) where a high-purity CO2 stream is produced suitable for transportation or other uses.
B&W provided oxy-fuel technology for use with coal on the DOE Future Gen 2.0 demonstration project in Meredosia, Illinois, which was a retrofit of a 200 MWe coal-fired power plant. Although construction began in 2014, the project was canceled in 2016 due to redirection of DOE funding support. However, oxy-fuel combustion technology is ready for near commercial-scale validation which will lead to full-scale commercialization and deployment.