Coal chemical-looping combustion (CLC) is an advantageous technology for CO2 capture. To maximize CO2 capture, the combustion efficiency should be improved. Certain factors such as oxygen carrier (OC) material, OC to coal ratio, temperature and gas environment affect the combustion rate and efficiency. This study used mixed metal oxides of cupper and iron with an inert support of silicon dioxide as an oxygen carrier (Cu-Fe-Si) for coal CLC. The goal of the combined Cu-Fe OC was to overcome the disadvantages of Fe-based OC slow reaction rate and low oxygen transport capability. The Cu-Fe OC will also attempt to improve the mechanical strength and reaction stability of the Cu-based OC. Cu-Fe-Si is attractive based on its availability from naturally occurring materials with low cost. The OC was prepared by mechanical mixing with different mass ratios of Cu to Fe oxides. The reactivity and stability of the OC with coal char was investigated at high temperature (up to 1100°C) in different gas environments (Ar, air and H2O). The impact of the OC to coal ratios on the Cu-Fe oxides redox system was studied by analyzing the copper and iron compounds in the test residues using XRD. CO2 capture efficiency was analyzed based on product gas compositions measured using a quadrupole mass spectrometer (QMS). Results show that the OC to coal ratio is a key factor on the combustion rate and CO2 capture efficiency. Cu-Fe-Si has potential as a competitive oxygen carrier in the coal chemical looping combustion process.

Bimetallic Cu-Fe oxygen carriers for coal chemical-looping combustion

255th National Meeting (2018)

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