Cu-Mn oxygen carrier with improved mechanical resistance: Analyzing performance under CLC and CLOU environments

Artikel i vetenskaplig tidskrift, 2021

Chemical Looping Combustion process allows combustion of gaseous, liquid or solid fuels with CO capture. The oxygen necessary for combustion can be supplied using lattice oxygen (CLC) or oxygen uncoupling (CLOU) mechanisms. The present work studies the effects of kaolin addition on Cu–Mn oxygen carrier behavior for CLC and CLOU processes. Cu–Mn oxygen carrier was prepared by granulation with a composition: 27.2 wt% CuO, 52.8 wt% Mn O and 20 wt% kaolin. Oxygen release rates and fluidization behavior were analyzed by TGA and batch fluidized bed reactor. The oxygen carrier was studied for CH and synthetic biogas combustion in a 500 W CLC continuous unit for 50 h of combustion at temperatures up to 930 °C. No agglomeration problems were observed. Results found during biogas combustion were similar to methane combustion. The addition of 20 wt% kaolin changed the mixed oxide chemical composition generating Cu Mn O and improved significantly the oxygen carrier mechanical resistance, increasing the extrapolated lifetime to 19,000 h, 3.6 times over the value found for any Cu based oxygen carrier in CLC. However, the oxygen carrier reactivity had an important decrease with respect to a similar oxygen carrier without kaolin addition, whose fraction in oxygen carrier must be optimized. 2 3 4 4 th 1.2 1.8 4