Study On The Composite Sulfur-fixing Agents Of Local Low-sulfur Briquette

In this thesis, local coal briquettes were prepared from Shanxi Jincheng coal. The influence of temperature, sulfur-fixing agents, sulfur-fixing asistants on the sulfur-fixing rate of coal briquette was investigated.The results indicate that temperature is an important factor which affects the sulfur-fixing efficiency of coal briquette. Considering the instability of the environment in the briquette oven, the experiments simulated the temperature of briquette combustion to ensure the experiments consistency and repeatability according to the real temperature dates during the coal briquette combustion.Influences of temperature on the properties of sulfur-fixing agents were studied in detail. The sulfur-fixing rate of three sulfur-fixing agents decreased with the increase of temperature. The sulfur-fixing rate of carbide slag was the highest, followed by limestone, blast furnace slag. The sulfur-fixing rate of carbide slag could be 79.26%、63.51% under low temperature. When the temperature increased to 1050℃, it`s sulfur-fixing rate fallen to 33.18%. The sintering under high temperature resulted in the decrease of surface area and the activity of sulfur-fixing agents, especially the blast furnace slag. But limestone has high activity under 1000-1050℃. It is good sulfur fixing agent used under high temperature. The experiments showed that carbide slag was active below 900℃, the limestone between 850℃ with 1050℃ had high sulfur-fixing rate, the blast furnace slag could be used as sulfur-fixing assistants under high temperature.Two kinds of sulfur-fixing agents were mixed for experiments. The results indicated two sulfur-fixing agents had higher sulfur-fixing rate than single sulfur-fixing agent. And two formulas(carbide slag: limestone = 60%:40%, carbide slag: blast furnace slag = 80%:20%) had good sulfur-fixing effect. According to the results of before, three kinds of sulfur-fixing agents were mixed for sulfur-fixing test. There were three formulas. After analyzing the sulfur-fixing rates and the SO2 adsorption rate, the first formula was the best formula. It was 53.6% carbide slag, 35.7% limestone and 10.7% blast furnace slag.The influence of sulfur-fixing assistants was very obviously. The results showed that Al2O3、Si O2 could improve the product of Ca Al(Al Si O7) and C4A3 S. These two products were more stable than Ca SO4. So the sulfur-fixing rate of coal briquette became higher than those without sulfur-fixing assistants. The sulfur-fixing agent contained 20% red mud, 20%bauxite, 20%bentonite had good sulfur-fixing effect. So 10% red mud, 10% bauxite, 10% bentonite were mixed for the best sulfur-fixing agent. It`s sulfur-fixing rate is highest.Analyzing the XRD-figure of ash without sulfur-fixing agents, 20% red mud, 20%bauxite, 20%bentonite and the best sulfur-fixing agent, the contents of ash were different. In a word, the sulfur-fixing assistants affected the sulfur-fixing reaction. They had different effect on the chemical contents of ash.