Performance of cement decorated copper ore as oxygen carrier in chemical-looping with oxygen uncoupling

Abstract

Chemical-looping with oxygen uncoupling (CLOU) provides a revolutionary route for CO2 capture with low energy consumption. To address the CLOU process, the appropriate oxygen carrier should have the ability of releasing gaseous oxygen in the fuel reactor and regenerating itself in the air reactor at temperatures of interest for combustion. Copper ore, known for its low cost and abundant reserves, has been identified as an applicable oxygen carrier material for CLOU. However, Cu-based oxygen carriers share the common disadvantages of sintering and agglomeration at high temperatures. To enhance the sintering-resistant property of copper ore particles, four types of cement decorated copper ore oxygen carrier were prepared by mechanical mixing. Successive cyclic redox experiments at different temperatures in a thermogravimetric analyzer (TGA) were first conducted to investigate the oxidation and reduction properties of the newly prepared oxygen carriers. The TGA results showed that within 20 cycles, cement modified copper ore (CuC) particles performed better redox reactivity than single copper ore oxygen carrier, especially at elevated temperatures. Among the CuC oxygen carriers, CuC-20 (copper ore modified with 20wt.% of cement) was the best in redox reactivity. Cyclic redox reactivity of Cu-ore and CuC-20 were further tested in a batch-scale fluidized bed reactor with both synthesis gas and coal as fuel at 950°C. The results both indicated that CuC-20 showed little tendency toward agglomeration and no chemical interaction between the active phase of copper ore and cement, which maintained stable and good reactivity after the activation process.