Abstract
Chemical looping conversion of coal (CLCC), an innovative technology, is an efficient and clean way for the utilization of coal. Oxygen carrier (OC) reduction by the coal is the rate-limiting process for the CLCC with deep OC reduction. K-decorated Fe2O3/Al2O3 OC, found to be a promising OC, can increase the reaction rate of OC and char. Unfortunately, due to the complexity of the OC the preparation conditions on the performance of this composite OC were not clear. In this study, the effect of Al2O3 content and calcination temperature on the activity and stability of Fe-based OC were investigated by thermogravimetric analysis (TGA), H2 temperature-programmed reduction (TPR), N2 adsorption analyzer, X-ray diffraction (XRD) and scanning electron microscope (SEM). The impact of K2CO3 loadings on the reactivity and stability of OC was also studied in a fix-bed reactor. In addition, optimal preparation conditions were screened out. The results showed that Al2O3 could increase the specific surface area of OC and anti-sintering ability. However, the Al2O3 had an adverse impact on the mechanical strength and reactivity of OC. The increase of calcination temperature of OC could increase the mechanical strength but decrease the reactivity of OC. The loading of K2CO3 could significantly improve the reactivity of OC, and K2CO3 was favorable for the redox stability of OC. The optimal preparation conditions of the composite OC are as follows: the addition amount of Al2O3 was 30%, the addition amount of K2CO3 was 5%, and the calcination temperature of OC was 1030 °C.
Published Version
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