Pressurized chemical-looping combustion of coal with iron-based industrial wastes as oxygen carrier

In this study, pressurized chemical-looping combustion of coal with iron-based industrial wastes and the cyclic durability of the iron-based industrial wastes were investigated in a laboratory fixed bed reactor. The results showed that the pressurized condition suppressed the initial coal pyrolysis process while enhanced the gasification process of coal char and the reaction between gasification products and oxygen carrier. With the increase of pressure, higher concentration of CO₂ and carbon conversion and lower concentrations of CO and CH₄ were obtained, also the conversion of the oxygen carrier was higher under higher pressure. With the increase of mass ratio of coal to oxygen carrier, the concentration of CO₂ and fuel conversion decreased due to the limited oxygen capacity of oxygen carrier, which is not favorable for CO₂ capture and the efficient use of energy. The cyclic experiments showed that the reactivity of the oxygen carrier increased with the increase of number of cycles, the conversions of volatile gases and gasification products of coal char increased as well as the fuel conversion.