【作者】 陈芳；

【导师】 杨春平； 甘海明；

【作者基本信息】 湖南大学 ， 环境工程， 2010， 硕士

【摘要】 我国工业锅炉量大面广,随着其对环境污染的日趋严重,发展中小型锅炉脱硫技术,削减中小型锅炉的S02排放量和排放达标已成为工业锅炉行业一项刻不容缓的任务。湿法烟气脱硫技术(WFGD)作为一种相对较成熟、脱硫效率较高的技术,是目前世界上应用最广泛的一种烟气脱硫方法,而石灰石/石灰-石膏湿法烟气脱硫是控制二氧化硫排放的最常用方法,但该法存在结垢、堵塞、副产品销路困难等问题。另外,我国石煤钒矿资源丰富,多用于湿法冶金提钒技术领域,到目前为止国内外还尚未出现利用钒矿脱硫的报道。传统从石煤中提钒主要采用添加氯化钠氧化焙烧工艺,该工艺在生产过程中产生大量的Cl2、HCl、SO2等有害气体和废水,严重污染周边环境,同时钒收率低、能耗高。针对以上2个问题,本文进行了以无氯钠盐作焙烧添加剂,焙烧后的含钠钒矿先用于回收焙烧过程中产生的SO2气体,再用稀酸浸取提钒的新工艺可行性研究。对焙烧阶段、烟气回收处理阶段及酸浸提钒阶段各种影响因素进行了分析。研究结果表明,所用焙烧添加剂为新型环保复合添加剂无氯钠盐,添加量10%,适宜的焙烧温度为850℃,焙烧时间为2.5-3.0h。矿样的入炉温度宜低不宜高,尤其对大规模的工业生产来说,当连续作业时,应当控制入炉温度在200℃以下；当进气压降为3.0kPa,气体流量为2350m3·h-1左右,钒矿浆液pH值在4.5以上时,脱硫.效率持续稳定在90%左右,整个过程长达20min。脱硫率随吸收剂循环次数的增加而增加,2次循环比1次循环的脱硫率高3.5%。吸收塔运行约40min后,塔中钒的平均浸出率为20%左右,脱硫渣再用5%的稀硫酸浸取10h后浸取率可达到62%；V205的浸出率随H2SO4浓度的增加而提高,当H2SO4浓度为15%,常温下浸取10h后浸出率达到最大值70.01%,硫酸浓度再增加,浸出率反而有下降趋势。焙烧钒矿是一种较好的新型脱硫剂,脱硫渣可副产具有工业应用价值的五氧化二钒产品,并且解决了传统提钒工艺中钠离子废水对环境造成的污染问题。因此,该法是一种较好的资源化烟气脱硫方法,可应用于脱硫或湿法冶金等行业。更多还原

【Abstract】 There are a lot of industrial boilers, and their distribution is very wide in our country. Along with their pollution to the atmosphere becoming more and more serious, developing desulfurization technologies of middle and small scale boilers and reducing emissions of sulfur oxides to the atmosphere has become an important and urgent work. Wet flue gas desulphurization technology(WFGD)as a relatively mature technology that has higher desulfurization efficiency, is the most widely used method in the world, and the most popular of which is the wet-type limestone/lime-gypsum process. Yet it often encounters problems such as fouling, clogging, and difficulty of selling the by-products during the system working. In China, especially in the southern provinces such as Hunan, Hubei, Zhejiang, Guizhou Province. There are abundant navajoite ore resources, which are often used in the field of hydrometallurgical technology, and there has not yet been reports of the use in desulfurization areas. In conventional technology, Vanadium Pentoxide(V2O5) is extracted from navajoite by roasting with adding sodium chloride. Large amounts of chlorine, hydrogen chloride, sulfur dioxide and other harmful gases and waste water produced in the process, simultaneously, the energy consumption is high, while the yield of vanadium is low.An innovative flue gas desulfurization (FGD) coupling process was proposed in this study to overcome the problems in wet-type limestone/lime processes which include fouling, clogging, and difficulty of selling the by-products and the problems in traditional process for vanadium extraction from navajoite ore such as excessive consumption of sulphuric acid and emissions of pollutants. The performance of a jet bubbling reactor(JBR) at pilot-scale was evaluated using navajoite ore produced in the process of extracting vanadium pentoxide as desulfurization absorbent.Results showed that roasting additives used in the process were the new environment-friendly chlorine-free sodium salt compound additives, the amount of adding additives was 10%, optimum calcination temperature was 850℃, roasting time was 2.5-3.0 hours. Temperature of putting ore sample into furnace should be controlled at lower temperature, especially for the large-scale industrial production, the temperature should be below 200℃; Navajoite ore slurry achieved better desulfurization performance than limestone slurry. When the inlet flue gas pressure drop was 3.0 kPa, the gas flow was about 2350 m·h-1 and the pH of the navajoite ore slurry was higher than 4.5, the desulfurization efficiency was stable about 90%; The SO2 removal efficiency appeared to increase along with the increasing of absorbent cycle-index. The efficiency of the second circulation was improved 3.5% compared to the first circulation; After an operating duration of 40 minutes, the leaching rate of vanadium pentoxide was about 20%, and reached 62% when the by-products were leached with 5% dilute sulphuric acid for 10 hours; The leaching rate of V2O5 improved along with the increasing of sulphuric acid concentration, and it could reach the maximum 70.01% when the sulphuric acid concentration was 15% and leaching time was 10 hours, however, the sulphuric acid concentration increased again, the leaching rate had a decreasing trend. The by-product from this process not only could be used to produce vanadium pentoxide which is a valuable industrial product, but also could significantly overcome the pollution problem existing in the traditional refining process of vanadium pentoxide when navajoite ore is used as the feed material. This FGD process using roasted navajoite slurry as absorbent is environmental sound and cost-effective, and shows the potential for application in the field of flue gas desulfurization as well as hydrometallurgy.更多还原