气液两相滑动弧放电处理火电厂含硫废气的研究

发布时间：2018-07-05 03:11

本文选题：滑动弧放电 + 烟气脱硫　；参考：《西安理工大学》2017年硕士论文

【摘要】：由于经济的迅速发展,电力市场的需求逐日增长,煤炭消耗量亦与日递增。燃煤电厂在发电过程中会产生大量大气污染物如SO_2, SO_2是导致酸雨形成的重要诱因。控制燃煤电厂烟气污染物排放对环境治理有着重要的意义。利用等离子体技术脱硫具有投资小,,占地面积小,处理效率高等优点,受到了世界各国科学家的关注。滑动弧放电是一种新型等离子体,因其兼具冷、热等离子体特性,能提供大量的高能电子和活性自由基,而被广泛研究应用于废气处理与烟气净化领域。木文首先选取SO_2为研究对象,改变实验条件如放电功率,气体流速,相对湿度,SO_2初始浓度等参数,研究不同的放电工况对处理效果的影响。实验结果表明:提高放电功率能够提高SO_2的去除率,放电功率的提高增大了放电区域的能量输入,增强了放电等离子体区域的电场,提高了放电区域活性粒子的数量和强度;气体流速越大,去除率越低,气流量的增大导致反应气的流速变快,气体在等离子体反应区域内的停留时间缩短,造成部分气体得不到充分反应就离开了等离子体区域,因而降解率随之下降;在低于饱和湿度的范围内,提高反应环境的相对湿度有利于提高SO_2的去除率。OH基团与SO_2之间的反应在整个去除过程中起关键作用。SO_2去除率随初始浓度的增加而降低,但能量利用率是提高的。在实际投入工业应用时,也应该考虑能量利用率的大小,寻求二者的一个交叉点,作为最佳初始浓度。为了提高气液两相滑动弧放电对火电厂废气的处理效率,将传统的纯水液相替换成NaOH溶液。通过观测放电过程中的电压-电流波形和发射光谱,研究加入NaOH对滑动弧放电的电气特性和光学特性的影响。选取SO_2作为待处理废气,对比分析NaOH溶液、纯水液相下SO_2的去除率以及产物浓度随处理时间、气体流速的变化情况,以及NaOH溶液浓度对SO_2去除结果的影响。实验结果表明,相同条件下,NaOH溶液代替纯水液相协强了气液两相放电强度,电离出更为大量的OH自由基;同时,NaOH的加入使SO_2的去除率提高了 5%～7%,产物中的SO_3含量较纯水液相时降低了 50%左右。实验结果表明,本文研究的气液两相滑动弧放电等离子体对于火电厂脱硫具有较高的效率。在工业污染物控制方面具有广阔的发展前景。本文的研究工作提出了一种火电厂污染物处理的新途径,为其今后在火电厂污染物处理领域的应用奠定了理论基础。
[Abstract]:With the rapid development of economy, the demand of electricity market increases day by day, and the consumption of coal increases day by day. A large number of atmospheric pollutants such as so _ 2s can be produced in coal-fired power plants. So _ 2s _ 2 is an important cause of acid rain formation. Controlling the emission of flue gas pollutants from coal-fired power plants is of great significance to environmental control. Desulfurization by plasma technology has attracted the attention of scientists all over the world for its advantages of small investment, small area, high treatment efficiency and so on. Sliding arc discharge is a new type of plasma, which is widely used in waste gas treatment and flue gas purification because of its characteristics of cold and thermal plasma, which can provide a large number of high energy electrons and active free radicals. At first, so _ 2 is selected as the research object. The experimental conditions such as discharge power, gas flow rate and initial concentration of so _ 2 are changed to study the effect of different discharge conditions on the treatment effect. The experimental results show that increasing the discharge power can increase the removal rate of SO2, increase the discharge power, increase the energy input in the discharge region, enhance the electric field in the discharge plasma region, and increase the number and intensity of active particles in the discharge region. The higher the gas flow rate, the lower the removal rate, the higher the gas flow rate, the faster the reaction gas flow rate, the shorter the residence time of the gas in the plasma reaction region, and the less sufficient reaction of some gases to leave the plasma region. As a result, the degradation rate decreases; in a range below saturated humidity, Increasing the relative humidity of the reaction environment is beneficial to increase the removal rate of SOS _ 2. The reaction between the OH group and so _ 2 plays a key role in the whole removal process. The removal rate of so _ 2 decreases with the increase of initial concentration, but the energy utilization rate is increased. In practical industrial application, the energy utilization ratio should also be taken into account, and an intersection of the two should be found as the optimal initial concentration. In order to improve the efficiency of gas-liquid two-phase sliding arc discharge in treating waste gas from thermal power plant, the traditional pure water liquid phase was replaced with NaOH solution. The effects of NaOH on the electrical and optical properties of sliding arc discharge were studied by observing the voltage-current waveforms and emission spectra during the discharge. So _ 2 was chosen as the waste gas to be treated. The removal rate of so _ 2 in pure water liquid phase and the change of product concentration with treatment time, gas flow rate and the effect of NaOH solution concentration on the removal of so _ 2 were compared and analyzed. The experimental results show that under the same conditions, the gas-liquid two-phase discharge intensity is strengthened in the presence of NaOH solution instead of pure water, and a large amount of OH free radicals are ionized. At the same time, the addition of NaOH increased the removal rate of SO2 by 5%, and the content of SO3 in the product decreased by about 50% compared with that in pure water liquid phase. The experimental results show that the gas-liquid two-phase sliding arc discharge plasma has a high efficiency for desulfurization in thermal power plants. It has a broad prospect in industrial pollutant control. In this paper, a new approach to pollutant treatment in thermal power plants is proposed, which lays a theoretical foundation for its application in the field of pollutant treatment in thermal power plants in the future.
【学位授予单位】：西安理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM621;X773

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