Burnout Characteristic of Coal Chars Under Oxyfuel Combustion Conditions

Burnout experiments of DT bituminous coal in oxyfuel combustion conditions were conducted in the flat-flame assisted entrained flow reactor.Ash tracer method was used to analysis the char burnout and element release behaviors.And the apparent reaction kinetic parameters based on the char oxidation reaction(C+0.5O_2 →CO) solved from the burnout curves using the shrinking core model.The results indicated that the reaction rate of pulverized coal under oxyfuel combustion condition was slower than that under air combustion condition.The oxygen atoms chemically adsorbed on char surface,resulted by the char-CO_2 gasification reaction,leads the reduction of release rate of oxygen element.The suppression effect of high content CO_2 on char burnout is more than promotion effect of CO_2 gasification reaction on char consumption at the high oxygen condition.The contribution of CO_2 gasification reaction on char consumption can be enhanced through reducing the oxygen concentration.