Oxygen Enriched and Oxyfuel Combustion - Promising Trends for Low Carbon Future
The escalation of ambient CO2 concentration due excessive use of coal in power generation has put impetus on the development of technologies for utilization of vast and cheap resources available through out the world. Eco-scrub, Oxygen enriched and oxyfuel combustion are among the promising technologies guaranteeing the low carbon future. In our recent investigations, pulverized coal (Russian) was fired in a 20 kW down fired combustion rig under simulated exhaust gas recirculation. The effect of CO2 at burner inlet on the combustion efficiency, flue gas CO2 and NO emission was studied. The test conditions were essentially achieved by replacing the secondary air with a mixture of O2 and CO2 in different proportion. The test conditions do imitate the four key conditions for eco-scrub project. The basic theme under eco-scrub project is to use limited oxygen addition to reduce the volume of flue gas for processing, increase the efficiency of post combustion scrubbing due to higher CO2 levels and reduced the size and cost of post combustion capture. The exhaust gas CO2 was observed to increase linearly with increasing the CO2 at burner inlet. The flue gas concentration for 35% and 45% flue gas recycle was recorded to be 24% and 30% respectively. The NO emission was most of the time under the base line emission of 818 ppm. A maximum of 66% reduction was observed when the burner inlet CO2 was 45% and 21% O2. How ever an increase of 37% was seen when 80% of the secondary air was replaced with a 50%O2-50%CO2 mixture.
M. T. Javed and B. Nimmo, "Oxygen Enriched and Oxyfuel Combustion - Promising Trends for Low Carbon Future", Applied Mechanics and Materials, Vol. 145, pp. 11-15, 2012