Investigation into the Reactivity Behavior of CaSO_4 with Coal Chars in the Chemical Looping Combustion System

摘要

Chemical-looping combustion is a promising method to realize the near zero emissions of CO_2 without any excessive energy penalty. In this paper the reactivity behavior of calcium sulfate (CaSO_4) as oxygen carrier (OC) with coal chars are investigated. After the impregnation of nickel ions or iron ions, the reacting behaviors of the OC are remarkably promoted comparing with that before the impregnation. The high impregnation of nickel ions or iron ions is beneficial to the reactivity of the OC, especially in the first half of the reaction. After the reaction of fresh CaSO_4 with coal chars, the solid products are merely CaS. In addition, the solid products of Ni-impregnated OC consist mainly of CaS, CaO and Ni_3S_2 while the solid products of Fe-impregnated OC are composed of Fe_3O_4 and CaS.