Study on the mechanism and reaction characteristics of metal-supported phosphogypsum as oxygen carrier in a chemical looping gasification application.

This study aimed to explore the chemical looping gasification (CLG) reaction characteristics of the metal-supported composite phosphogypsum (PG) oxygen carriers (OCs) and the thermodynamic mechanism. The FactSage 7.1 thermodynamic simulation was used to explore the oxygen release and H ₂ S removal mechanisms. The experimental results showed that the syngas yield of CLG with PG-CuFe ₂ O ₄ was more than that with PG-Fe ₂ O ₃ 20/CuO40 or PG-Fe ₂ O ₃ 30/CuO30 OC at 1023 K when the water vapor content was 0.3. Furthermore, the maximum syngas yield of the CO selectivity was 70.3% and of the CO ₂ selectivity was 23.8%. The H ₂ /CO value was 0.78, and the highest carbon conversion efficiency was 91.9% in PG-CuFe ₂ O ₄ at the gasification temperature of 1073 K. The metal-supported PG composite oxygen carrier was proved not only as an oxygen carrier to participate in the preparation of syngas but also as a catalyst to catalyze coal gasification reactions. Furthermore, both the experimental results and FactSage 7.1 thermodynamic analysis revealed that the trapping mechanism of H ₂ S by composite OCs was as follows: CuO first lost lattice oxygen as an oxygen carrier to generate Cu ₂ O, which, in turn, reacted with H ₂ S to generate Cu ₂ S. This study provided efficient guidance and reference for OC design in CLG.
Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this study.
(Copyright © 2023. Published by Elsevier B.V.)