Thermodynamic and kinetic analysis of CuO-CaSO4 oxygen carrier in chemical looping gasification

Abstract

Chemical looping gasification (CLG) is an efficient coal gasification method and an emerging technology. In this process, the oxygen is from oxygen carriers such as CuO-CaSO4. The great reactivity characteristic of CuO-CaSO4 compound oxygen carrier has been confirmed by previous work. And, thermodynamics and kinetics are the vital parts of CLG process. To better understand the process of CLG with CuO-CaSO4, the thermodynamics and kinetics of CuO-CaSO4 CLG process has been investigated. In this work. A novel way was proposed to prepare to CuO-CaSO4 oxygen carrier with the industrial wast phosphogypsum (PG). And it showed that the molar ratio of PG to Cu element should be around 2. Activation energy was investigated by isoconversion method. In the CLG process, Activation energy was 86.4556 kJ/mol with CuO-CaSO4, However the activation energy was 145.6092 kJ/mol, when applied PG as oxygen carrier. Deeper studies showed that the mechanism of CLG with CuO-CaSO4 was controlled by product layer diffusion mechanisms of Shrinking Core Model (SCM) model. Therefore, theses phenomena indicate that CuO-CaSO4 is a recommended oxygen carrier in chemical looping technology.