Chemical looping with oxygen uncoupling of coal: comparison of synthetic CuO/ CuAl2O4 and copper ore as oxygen carriers

In order to study the performance differences of synthetic Cu-based oxygen carrier (OC) and natural copper ore OC in chemical looping with oxygen uncoupling (CLOU) process of coal, comparative investigations of oxygen release performance of sol-gel made CuO/CuAl2O4 and natural copper ore as oxygen carriers were first conducted in a thermogravimetric analyzer (TGA). Subsequently, CLOU experiments of Gaoping anthracite (GP Coal) were performed in a batch-scale fluidized bed reactor, using CuO/CuAl2O4 and natural copper ore as OC, respectively. TGA experimental results show that both the oxygen release rate and oxygen transport capacity of CuO/CuAl2O4 are higher than that of copper ore, and the oxygen release property of the two oxygen carriers could maintain very well during cyclic TGA tests. During the CLOU experiments of GP coal in fluidized bed reactor, CuO/CuAl2O4 generally exhibits much higher carbon and OC conversion rates than that of copper ore OC. The CO2 yield of the two kinds of OCs maintain relatively high value (higher than 0.93) at the temperature range of 850-950℃, and the cyclic redox experiments indicate that they perform very good reactivity and stability within the CLOU process. © 2015, China Coal Society. All right reserved.