Cyclic reactivity of the sol-gel and graphite impregnation-derived Cu-based oxygen carriers for chemical looping with oxygen uncoupling

Chemical looping with oxygen uncoupling (CLOU) is a promising technology to be used in combination with the oxy-fuel combustion/gasification processes for carbon capture and sequestration in that it reduces the energy penalty for O(2)generation; hence, much attention has been focused on the production of proper oxygen carriers. In this work, four oxygen carrier candidates for CLOU made of 90% CuO and 10% ZrO(2)or Y(2)O(3)are first prepared with the sol-gel and graphite impregnation methods. The reduction reactivity of the prepared oxygen carriers is investigated at 900, 950, and 1000 degrees C in the CO(2)atmosphere, and the redox stability is evaluated through ten sequential cycles using the thermogravimetric analyzer. It is found that the Avrami-Erofeev random nucleation and subsequence growth model (A2) describes the reduction process very well. CuO/ZrO(2)prepared by the graphite impregnation performs better reactivity and stability than the others. The agglomeration and sintering of the oxygen carriers at high temperatures are found to be the main cause of the low reactivity over the repeated cycles.

Automated summary

This study prepared four oxygen carrier candidates for CLOU for the first time, finding that CuO/ZrO(2) prepared by the graphite impregnation method showed better reactivity and stability compared to others, with agglomeration and sintering of the carriers at high temperatures identified as the main cause of low reactivity over repeated cycles.