Syngas production by chemical looping gasification using Fe supported on phosphogypsum compound oxygen carrier

Abstract

Chemical looping gasification (CLG), which is a method for syngas production. The materials for the syngas are low-quality lignite and the industrial waste-phosphogypsum (PG). However, the reaction temperature for the process is high, which consumes a lot of energy. Therefore, in this work, a catalyst has been proposed to lower the reaction temperature in the CLG of syngas. Ellingham diagram has been used as a guide to find the catalyst. Furthermore, theoretical calculations using the thermodynamic software FactSage, have been conducted along with experiments to analyze the performance of compound oxygen carrier in the CLG process. After the analysis, it is suggested that the Fe supported PG has great characteristics with high oxygen carrying capacity, high selective conversion ability of C to CO, excellent activity and recyclability. In addition, compared with the PG applied used as oxygen carrier, the compound oxygen carrier has reduced the temperature to 1023 K with more than 90.00% carbon conversion, whereas more than 70.00% of carbon of lignite is transformed into CO. Additionally, the syngas has the cold gas efficiency of 81.38% and the lower heating value (LHV) 3222.52 kJ/Nm3. And, Fe promotes carbon conversion and syngas production mainly through the reactions: <Fe2O3+3CH4→2Fe+3CO+6H2> and <Fe2O3+3C→2Fe+3CO>.