This paper presents calculations of oxygen-enriched coal combustion. Enriching combustion air with oxygen is considered one of the most effective methods to improve thermal efficiency, reduce pollutant emissions such as NOx, and facilitate capture of CO2 pollutant from flue gas. In addition to solving transport equations for the continuous phase (gas), a discrete second phase (spherical particles) is simulated in the Lagrangian frame of reference. Reaction is modeled by a two-mixture fractions/PDF approach. Discrete phase modeling is used for the prediction of discrete phase trajectory and heat and mass transfer to and from particles. The coal used is a Canadian high sulfur bituminous coal. The mass fraction of oxygen in the combustion air was varied from 21% (air) to 100% (pure oxygen). The results show that the temperatures of the gas phase and coal particles increase, respectively, by 13% and 9% when the mass fraction of oxygen is increased from 21% to 100%. One important result is that the CO2 in the oxygen/coal exhaust stream is at a much higher concentration (50% higher) compared with the air and coal exhaust stream highly diluted by N2. This will help the capture of CO2 emissions from flue gas and consequently reduce the CO2 capture costs.

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