NOx and SO2 emissions from O2/CO2 recycle coal combustion

Capturing CO2 from conventional coal-fired power plant is very costly because of its relatively dilute concentration in the flue gas. One option to reduce the cost of gas separation is to increase CO2 concentration in the flue gas by eliminating nitrogen before combustion and by recycling part of the flue gas. This scheme is known as O2/CO2 recycle combustion. The present work focuses on the implications of O2/CO2 recycle combustion on NOx and SO2 emissions. Two main types of experiments were performed: combustion in once-through O2/CO2 mixtures and experiments with recycled flue gas. Combustion in air was performed as a base case. For each experiment, NOx and SO2 were measured at several locations along the reactor and the experimental results are presented in this paper.