Experiment Research Of Additives On Sulfur Capture During Coal Combustion And Analysis Of Mechanism On Promoting Effect

The sulfur dioxide pollutant derived from coal combustion was a serious worldwide problem. The total sulfur dioxide emission in China was foremost in the world. Sulfur capture in furnaces was competitive for controlling the SO₂ pollutants, due to the low capital and operating costs. But it had some shortcomings, such as the low using efficiency of Ca-based, sulfate product redecomposing easily during high temperature, leading to the low desulfurization efficiency. In this thesis, additives were researched to increase the sulfur capture efficiency, and effect and mechanism additives affecting sulfur capture efficiency were discussed.Put the importance on four mail factors, such as burning temperature, Ca/S mol ratio, sulfur capture sorbent and the size of coal particle, based on the representative coal, characteristic of four sulfur capture sorbents were investigated. It was found that calcium carbide residue showed the best activity.The additive effect of 12 kinds different single-composition was investigated. The promoting effect of additive was affected by different factors, and the temperature showed the most distinct influence. It was found that different additives produced different promoting effect on calcium carbide residue sulfur capture and the promoting effect and mechanism were dissimilar. For example, the promoting effect of MnO₂ and Fe₂O₃ were the more prominent at low temperature than at high temperature. By contraries, K₂CO₃ showed the more remarkable at high temperature than at low temperature. And rare earths oxide showed good catalyzing character. And this important result was not reported now.Based on the single-composition experiment, 13 kinds double-composition additives were researched. It were concluded that, on the condition of the additive total quality of 1.0% of coal and the temperature of 900℃, when K₂CO₃ and MgO mol ratio was 0.1 the sulfur capture ratio got 77.99% the best result, and the second was 74.21% when MnO₂ and Fe₂O₃ mol ratio was 0.1. At last, three compositions additive were studied, and the sulfur capture ratio of two composite additives, which were named KMM and MFK, was higher than 84%.The coal samples were analyzed through TG and DTG and the cinder was characterized through XRD and SEM. The result showed that the thermal stability...