Characteristic Evaluation and Process Simulation of CuFeO as Oxygen Carriers in Coal Chemical Looping Gasification.

Chemical looping gasification (CLG) has been described as an innovative and low-cost gasification technology to convert carbonaceous fuels into synthesis gases. Oxygen carrier (OC) is the key to resolve the contradiction between rapid carbon conversion and appropriate partial oxidation of coal. At present, the solid fuel conversion in the CLG process is limited by an iron-based OC, and a copper-based carrier has difficulty in maintaining the reduction atmosphere. Hence, CuFeO has been proposed as a high-performance OC because of its synergistic effect. The present study first conducted a characteristic evaluation on CuFeO, including the reducibility and oxygen release capacity. The results showed that the addition of copper made a great contribution to the reduction process, and the presence of ferrite better relieved the deep oxygen loss of CuFeO. The thermodynamic limitation and evolution behavior of CuFeO in the reduction process were discussed for the simulation. An Aspen model of the CLG process with coal as the fuel and CuFeO as the OC was then established and validated by the experimental data. By consideration of the high carbon conversion and high syngas productivity in the operation, an OC/fuel mass ratio of approximately 1.25-2.25 and a gasification temperature range of 800-900 °C were thought to be optimal in the coal CLG process.