SO2 removal performances of Al- and Mg-modified carbide slags from CO2 capture cycles at calcium looping conditions

In this work, the SO 2 removal performances of the aluminum- and the magnesium-modified carbide slags fabricated by the combustion synthesis from CO 2 capture cycles at the calcium looping conditions were investigated in a thermogravimetric analyzer and a dual fixed-bed reactor. The effects of sulfation temperature, number of CO 2 capture cycles and calcination condition on the SO 2 removal performances of Al- and Mg-modified carbide slags experienced the multiple CO 2 capture cycles were studied. The sulfation temperature in the range of 800–950 °C shows a little effect on SO 2 removal capacities of Al- and Mg-modified carbide slags experienced the multiple CO 2 capture cycles. As the number of CO 2 capture cycles increases, the sulfation conversions of the original and modified carbide slags decrease rapidly. However, Al- and Mg-modified carbide slags possess obviously higher SO 2 removal capacity and cyclic stability than original carbide slag due to the good supports Ca 3 Al 2 O 6 and MgO, respectively. And the larger surface areas and volumes of pores in 5–20 nm in diameter of Al- and Mg-modified carbide slags promote the higher SO 2 removal capacity than original carbide slag. The modified carbide slag shows higher sintering resistance in high concentration of steam calcination condition during the CO 2 capture cycles, compared with high concentration of CO 2 calcination condition. Therefore, Al- and Mg-modified carbide slags from CO 2 capture cycles based on calcium looping calcined under high steam concentration achieve SO 2 removal capacities.