Effects of CaO-MgCO3 on the combustion behavior and emission properties of SO2 and NOx during semi-coke combustion

Abstract

The effect of CaO-MgCO3 additives on the combustion property of semi-coke (SC) was investigated using thermogravimetric analysis. Based on the experimental results, the addition of CaO (Ca/S = 2) on SC could reduce the ignition temperature (about 1.3 °C) and burnout temperature (about 0.99 °C). Besides, the additive of CaO on SC had significantly decreased the emissions of SO2 and NOx. However, the addition of 1 wt% MgCO3 on SC-CaO could promote the burning process and remarkably reduce the ignition temperature (about 10 °C) and burnout temperature (about 8.64 °C). Moreover, the smallest activation energy was available for the combustion of SC-CaO-1 wt% MgCO3. On the other hand, the addition of MgCO3 with different content (0.5 wt%, 1 wt%, 2 wt%, 4 wt%) on SC-CaO could enhance the pore size of CaO, promote the sulfur fixation performance. Comparing with other SC-CaO-MgCO3 samples, the addition of appropriate amount of MgCO3 (1 wt%) could effectively promote the catalytic desulfuration and denitrification of CaO. Therefore, CaO-1 wt% MgCO3 could effectively inhibit SO2 and NOx emission, which had great potential to be an efficient and clean method for the large-scale utilization of semi-coke.