Reaction of spinel CuFe2O4 oxygen carrier with converter off-gas during chemical looping combustion: An experimental characteristic and decomposition kinetic study

Converter off-gas, an important by-product in the steel industry with CO (<15 %) and O-2 (>2 %) as the main components, is toxic, explosion risk and difficult to capture. Herein, we propose a method to produce pure CO2 via chemical looping combustion by using converter off-gas as reducing agent, which can easily concentrate CO2 for capture. It was found that the CuFe2O4 could strongly improve the activity for CO conversion, and almost regenerate the reduced oxygen carrier by air oxidation. Under the atmosphere of 8 % CO and 3 % O-2, CuFe2O4 was reacted for ten cycles at 850 degrees C, the average CO conversion, CO2 selectivity, and CO2 yield reached 95.41 %, 98.08 %, and 93.58 %, respectively, nearly realizing the complete CO2 capture. XRD and Raman analysis shows that CuFe2O4 can almost be regenerated after ten cycles with no carbon accumulation on the surface. Meanwhile, SEM and XPS analysis shows that the fresh CuFe2O4 surface is dense, CO inlet/outlet channels are formed on the surface after cycled, and CO2 was produced through reaction of mainly the lattice oxygen with CO. The expression of the control function for the thermal decomposition mechanism of CuFe2O4 in Ar environment as G(X)= [-ln(1-X)](1/3), its average activation energy E = 33.41 KJ/mol, and the average finger forward factor A= 1.374 center dot 10(12) s(-1).