【作者】 陈福寿；

【导师】 杜军；

【作者基本信息】 重庆大学 ， 物理化学， 2008， 硕士

【摘要】 我国的能源结构是以煤炭为主,煤炭燃烧以后排放SO2造成的大气污染已经成为一个相当严重的问题,对燃煤固硫问题进行深入研究,控制SO2的排放已势在必行。在现有的脱硫技术中,干法钙基固硫技术工艺简单、脱硫成本低,特别适合生活燃煤、小型工业窑炉以及老锅炉的固硫改造。然而单一的钙基固硫剂钙利用率低,固硫效果有限,影响了该技术的发展,采用在钙基固硫剂中加入助剂制成复合固硫剂来提高固硫效率是一种较为经济可行的方法。本文通过对三种单一物质和两种固体废弃物对钙基固硫剂的固硫促进效果的考察,发现碱金属盐以及稻草灰(RSA)都是很好的钙基固硫添加剂,相比而言,RSA/钙基复合固硫剂更适合民用燃煤固硫。考察了各工艺条件诸如RSA与CaCO3的配比、Ca/S摩尔比以及燃烧情况等对RSA/CaCO3复合固硫剂固硫效果的影响,并利用RSA/CaCO3复合固硫剂进行了现场的民用型煤固硫实验,还利用XRD对固硫灰渣的物相成分进行了分析。此外,还对钙基固硫剂进行调质处理,大大提高了其在高温阶段(1100℃以上)的固硫效果。实验结果表明:CaCO3与RSA的最佳配比为10:1;Ca/S摩尔比最佳取值范围为1.5-2.5;复合固硫剂的最佳固硫温度为800℃-900℃;在固硫煤样中加入4%的水分能够得到较佳的固硫效果;最佳空气流量为150ml/min。当Ca/S为2.0、空气流量150ml/min时,复合固硫剂在800℃的固硫率达到70%以上。民用型煤固硫实验结果显示,本固硫剂对无烟煤和烟煤都有很好的固硫效果,固硫率高达90%。固硫灰渣XRD图谱显示在1000℃以下,主要固硫产物为CaSO4,而1100℃时固硫灰渣中有高温物相2Ca2SiO4·CaSO4的生成。通过对CaCO3调质处理,1100℃时钙基固硫剂的固硫率能够由16%左右增加到40%,1250℃时的固硫率也能够达到20%。XRD分析显示,煅烧熔融使粉煤灰得到了活化,而在1250℃时固硫灰渣的XRD图谱中出现了3CaO·Al2O3·CaSO4的吸收峰。更多还原

【Abstract】 Coal is the main energy in china’s energy structure. SO2 from coal combustion is one of the major air pollutants, leading to serious environmental pollution. Thus, it is urgent to control the emission of SO2. Among all kinds of desulphurization technologies, dry calcium-based retention technique is the most suitable one for civil coal combustion, small-scale industrial furnace as well as old boiler due to its simple process and low cost. However, low desulfurization efficiency and low utilization ratio of calcium have limited the development of this technology when using calcium-based absorbent alone. A new economic method, doping some additives into the Ca-based absorbent, has been developed to resolve this problem.It was found that alkali metal salts and rice straw ash(RSA) are both appropriate calcium-based absorbent additives, by investigating the desulphurization promoting of three different pure chemical additives and two different solid wastes. Compared with pure chemical additives, RSA is more suitable for civilian coal. The effect of rice straw ash ratio, Ca/S, combustion conditions were investigated, and civil briquette experiments were carried out at the scene. The phases of the sulfur retention ash were also analyzed by XRD. The calcium-based sulfur retention absorbent was treated by Acetic acid and activated fly ash (FA), and the sulfur retention efficiency was greatly improved when the temperature is above 1100℃.The results of the experiment show that the optimize process conditions of RSA/ CaCO3 sulfur retention absorbent are as fellow: mass ratio of CaCO3 and straw ash is 10:1, the Ca/S ratio is between 1.5-2.5, the temperature is between 800℃-900℃,the amount of additional water is 4%, and the air flow is 150 ml/min. The sulfur retention rate of RSA/CaCO3 is above 70%, When Ca/S = 2.0, the air flow is 150 ml/min and the temperature is 800℃.The Civil briquette experiments results show that, the sulfur retention absorbent has the higher sulfur retention efficiency to both anthracite and bituminous coal, which reached to 90%. The sulfur retention rate increased from 16% to 40% at 1100℃by acetate-quality processing and activated FA; when the temperature is 1250℃, the sulfur rate reached to 20%.The XRD patterns indicated that, the main form of sulfur in the sulfur retention ash are CaSO4 when temperature is below 1000℃; 2Ca2SiO4·CaSO4 is found when the sulfur retention temperature is 1100℃; the absorption peaks of 3CaO·Al2O3·CaSO4 are also found When the temperature rises to 1250℃.更多还原