Formation Mechanism Of High-Temperature Sulfur Retention Phase-Sulphoaluminate And Influence Of Atmosphere

Coal is an important resource in our country. As the consumption of coal becomes larger by power plant boiler, it is more urgent for us to utilize the desulphurization slag. in this paper, with focus on the idea of resource-energy-environment integration and resolving the problem that the desulphurization rate is low and traditional desulfuration production CaSO4 is easy to decompose during coal combustion at high temperature, combustion characteristic of coal and the production mechanism and the influence factors of sulphoaluminate for desulfuration were investigated which has the important practical meaning to solve problem of coal utilization By the means of thermo-gravimetric analysis, chemical analysis, XRD and Flue gas analyzer.This paper investigated the combustion characteristic of coal by the means of TG analysis and flue gas analyzer. The results show that the emission rules of SO2 are different because of the type of coal; the decomposition area of Sulfur-containing material is well displayed; Organic sulfur usually decomposes within 200s. Flue gas analyzer can determine sulphur content of coal. The combustion characteristic of coal is investigated by the means of TG analysis. Then we obtain fire index, combustion characteristic and some other important indexes; evaluate the quality of coal whether it is Superior or inferior. At last, the best coal has been selected.The formation mechanism of sulphoaluminate and influence of atmosphere were investigated by the means of XRD and chemical analysis. The results show that sulphoaluminate is a better sulfur containing matter which is high temperature stability. It begins to form and increases with the rising of temperature. Up to 1400℃, it is also stable. The atmosphere of oxygen is beneficial to the formation of sulphoaluminate, decreasing the Emission of SO2; the material reduction can significantly promote the decomposition of calcium sulfate that lead to the low desulphurization rate and the disadvantage of absorbing free calcium oxide.In the practical processes of coal, the formation of sulphoaluminate is influenced by the impurities which exist in the coal. The formation of sulphoaluminate and influence of material reduction have been carried by evaluating desulphurization efficiency and the analysis of mineral composition. The results show that the desulphurization efficiency is lower with the up of temperature. Above 1200℃, calcium sulfate decomposes rapidly, so the decreasing rate of desulphurization efficiency is very fast; The stronger the material reducibility is, the more the emission of SO2 will be, the lower the desulphurization efficiency is. From the emission of SO2 and the desulphurization efficiency, oxygen atmosphere is better than air atmosphere. Due to the influence of harmful minerals, the formation of sulphoaluminate is blocked. The amount of sulphoaluminate is largest in 1100℃as well as the desulphurization efficiency. So the best temperature for the formation of sulphoaluminate is 1100℃.