Pressurized oxy-combustion is a promising technology that can significantly reduce the energy penalty associated with first-generation oxy-combustion systems designed to capture CO2 in coal-fired power plants. However, higher pressure increases the production of strong acid gases — including sulfur trioxide (SO3) and nitrogen dioxide (NO2) — and aggravates the threat of corrosion. The formation of SO3 and NO2 in the gas phase and their interaction have not been adequately addressed, particularly at elevated pressures.
At LACER, we have constructed a detailed chemistry model, including a subset of sulfur chemistry, nitrogen chemistry and SOx-NOx interactions. By validating this detailed chemistry against reported measurement data, we have been able to estimate the formation of SO3 and NO2 in pressurized oxygen-combustion furnaces and concisely demonstrate their formation pathways. We also have developed a skeletal mechanism and a reduced mechanism to help understand this chemistry.