摘要
采用共沉淀法制备氧化镁基吸附剂,开展烟气干法脱硫研究。模拟燃煤烟气脱硫,分析吸附剂制备时的焙烧时间和温度以及脱硫过程中的有氧、无氧等条件对脱硫效率、硫容、比表面积和脱硫时间等因素的影响。确定吸附剂制备的最佳工艺条件为:焙烧温度550℃,焙烧时间2h。此时吸附剂的比表面积(BET)为21.3982m2/g,硫容为6.8mg/g。研究表明,氧化镁基吸附剂可以进行烟气干法脱硫,氧气对脱硫起促进作用。
The present paper is concerned about our newly improved method in preparing magnesia-base adsorbent through our study- of coprecipitation and flue gas-treated dry desulphurization. For this purpose, first of all, we have conducted experimental analogy by burning the coal flue gas desulphurization so as to analyze the desulfuration efficacy, its content of sulfur, the desulfuration time and the other similar factors by changing the adsorbent roasting time and temperature, as well as desulfuration process with or without oxygen presence. In doing so, we succeeded in granulating, roasting and drying the magnesium-based adsorbent and making it activated at different temperature ranges in 2 hours, so as to make the specific area of the adsorbent and sulfur capacity enhanced significantly. That is to say, it is possible to gradually increase the specific surface area lower than 550 ℃ so as to make it reach the maximum temperature of 550 ℃ . Nevertheless, with further increase of temperature, the adsorbent specific area would begin to drop remarkably. At calcination temperature of 550 ℃ , with the increase of baking time, the specific surface area and sulfur capacity tend to increase significantly and then reach their maximum value in 2 h, and later would be slowly declining, with the fall tendency getting slower and slower in 3 h. In addition, we have also found that, under three different conditions of the flue gas temperature, that is, 30 ℃, 90 ℃, 150 ℃, the rise of the flue gas temperature is not favorable for the increase of desulphurization efficiency. Moreover, the simulated flue gas proves to be oxygen-absent, with the desulphurization efficiency dropping significantly, particularly within 30 -50 min. Thus, our experimental results prove that oxygen is favorite for desulphurization, the adsorbent preparative roasting temperature should be at 550 ℃ , at best roasting time length of 2 h. It also shows that it is possible to proceed flue gas dry desulphurization at the presence of magnesia base adsorbent with oxygen accelerating the process of desulphurization. What is more, it has proved that with the help of magnesia base adsorbent, the higher decomposition temperature, the more thorough decomposition reaction will be, and the more efficient the removing rate either of hydration water or of COa, and, in turn, the easier the sinter, mechanical strength fall, as well as the quicker specific area degression and sulfur capacity homologization. From what is said above, it can be concluded that our analysis helps to disclose the essential process of desulphurization, which is by nature the production of SO2 with the help of oxygen and in which SO2 or SO3 are simultaneously united inside and outside of the superficial of magnesia absorbent＇ s crystal plane. In addition, six steps prove to exist in the magnesium adsorbent gas-solid phase adsorption process.
出处
《安全与环境学报》
CAS
CSCD
2008年第3期33-36,共4页
Journal of Safety and Environment
基金
沈阳科学技术计划项目(1071057-9-00)
关键词
环境工程
干法烟气脱硫
吸附剂
硫容
比表面积
environmental engineering
dry flue-gas desulphurization
sorbent
sulfur capacity
BET
