Study of the combustion behaviour of Indian coals in oxy-fuel environment

Study of the combustion behaviour of Indian coals in oxy-fuel environment

Abstract

Oxy-fuel combustion is one of the promising technologies for the direct capture of CO2 from power generating units. In this technology, the coal is combusted using pure oxygen in the absence of nitrogen, so that the obtained combustion product is predominantly CO2 which can directly be sequestered and the re-circulated flue gas is used in place of nitrogen for getting moderate temperatures in the boiler. The oxy-fuel combustion occurs in CO2-O2 environment where as the normal air combustion occurs in N2-O2 environment. As the CO2 is having high molecular weight, high density, high specific heat capacity (about 67% more than N2 at high temperatures) and varying radiation properties compared to N2, the heat and mass transfer in CO2-O2 (oxy-fuel) combustion is different to that of normal air combustion and this also leads to varying flow profiles and heat flux distributions within the furnace. While considering the retrofit of existing normal air operated coal fired furnaces with oxy-fuel mode, it is imperative to investigate these varying transport phenomena in detail. The seminar proposed will bring out the results of the studies carried out on the combustion behaviour of some of the Indian coals in oxy-fuel and normal air environments through lab-scale experiments and CFD simulations.