Process design and performance analysis of a Staged, Pressurized Oxy-Combustion (SPOC) power plant for carbon capture

Support for carbon capture, utilization and storage (CCUS) for coal power plants is limited, to some extent, by the high cost of electricity associated with available technologies. While a comparison of different capture methods favors oxy-combustion technology, the cost is still prohibitively high and the efficiency is low. The requirement that CO2 must ultimately be delivered at high pressure for storage or enhanced oil recovery has led to interest in pressurizing the combustion process, whereby the latent heat in the flue gas moisture can be largely recovered and integrated into the Rankine cycle, thus increasing the plant efficiency. In this work, the performance of a novel Staged, Pressurized Oxy-Combustion (SPOC) process is presented, which has the potential of increasing plant efficiency even further via reduction of auxiliary loads associated with flue gas recycle and flue gas cleanup. Heat flux and temperature are controlled with fuel staging and burner design. ASPEN Plus modeling of a conceptual power plant using the SPOC approach shows an improvement in efficiency of over 6 percentage points over first generation atmospheric oxy-combustion technology. The process design and results from ASPEN Plus modeling are described.