Fundamental Concepts

This chapter gives an overview of the fundamental concepts involved in the research of chemical looping combustion. The principles of two types of chemical looping process for solid fuel, that is, the in situ gasification chemical looping combustion (iG-CLC) and chemical looping with oxygen uncoupling (CLOU) are elaborated. To realize high-efficiency combustion, different types of reactors including the bubbling fluidized bed, spouted-fluidized bed, and circulating fluidized bed as well as the moving bed are used for CLC process. In addition, the concept of fixed bed has also been applied to the combustion of gas fuels with the advantage of simple design. Another critical component for CLC is the oxygen carrier, which can be metal oxides such as NiO, CuO, Fe2O3, Mn3O4, and nonmetal oxides such as CaSO4. Finally, the calcium looping combustion, another carbon capture technology, is briefly introduced. In recent years, magnesium looping and manganese looping have also been investigated, but they are not included in this book.