Effect of ash on coal direct chemical looping combustion

Although major coal deposits are of high ash content, chemical loop combustion (CLC) technology for these coals are yet to be perfected. Thus, to evaluate the effect of ash on CLC process, a CFD model which incorporates both fuel and air reactors and their inter-connecting parts of a given pilot plant has been developed. The model results for sub-bituminous coal and metallurgical coke for CLC process have been validated against the published data within an error band of +/- 7-14%. The validated model is then used for two high ash content coals designated as A and B. Simulated results show that fuel conversions for A and B, are 93.8% and 87.79% respectively and that purity of CO2 in fuel reactor exhaust are 89.12% and 90.73%. It is further observed that, ash components such as CaO, Fe2O3 exhibit significant reactivity at the operating conditions, whereas, it is negligible for SiO2.