低温等离子体协同SCR的烟气脱硝研究

发布时间：2018-06-26 20:31

  本文选题：烟气脱硝 + 低温等离子体　； 参考：《大连理工大学》2015年硕士论文

【摘要】：氮氧化物(NOx)作为燃煤烟气中主要的气态污染物,对人类和生态环境造成严重的威胁。低温等离子协同催化剂具有反应速率高、不产生二次污染等特点,在污染物脱除领域受到广泛关注。本研究针对工业烟气低温脱硝难度大、催化剂用量多等问题,提出利用低温等离子体对NO预氧化与SCR协同快速脱硝,为NOx在低温度窗口下脱硝探索一条新方法。本文研究了沿面放电氧活性物质注入协同SCR和电晕放电协同SCR两种烟气脱硝方式。在沿面放电氧活性物质注入中,清洁空气通过沿面放电活化产生的氧活性物质注入到烟气中,将其中部分NO氧化；而在电晕放电中,烟气则通过放电区域,NO的氧化反应发生在低温等离子体的发生区域。经过低温等离子体预氧化后,烟气进入SCR反应装置完成脱硝反应。本研究的主要工作及结果如下：(1)在低温等离子体发生器优化条件下,分别考察沿面放电氧活性物质注入和电晕放电对含NOx的模拟烟气的预处理效果。O3是沿面放电氧活性物质注入氧化NO氧化的主要活性物质,而在电晕放电氧化的过程中,包括O·和OH·则都能参与到NO的氧化反应中。(2)沿面放电氧活性物质注入中,NO氧化效果随着电压的升高而升高,放电长度120mm,注入流量75mL/min,烟气温度150℃的实验条件下,负载电压2.7 kV时NO氧化效率为50%。(3)在电晕放电中,烟气中含有一定量的H2O则对NO的氧化有显著的促进作用,这归因于H2O电离产生的OH·具有极高的氧化电位,对NO的氧化能力极强。(4)在150℃时,低温等离子体协同SCR反应的脱硝效率比单独SCR提高了23%。低温等离子体将烟气中部分NO氧化形成N02,在催化剂表面形成NO3和NO2。一方面,NO2可以直接与NH3发生还原反应,另一方面,NO3对V4+-OH再氧化的加速作用进一步强化了低温窗口下催化剂的脱硝能力。在高硫、高湿两种烟气的环境下,沿面放电协同SCR比标准SCR情况下的脱硝效率分别高出了31.9%和21.5%。而在电晕放电协同SCR中,H20的存在还会在电晕放电后引发低温等离子体脱硝,脱硝效率比标准SCR效率高53%；当向高湿的模拟烟气中加入SO2时,脱硝效率则比单独SCR情况下脱硝高出60%。
[Abstract]:Nitrogen oxides (NOx), as the main gaseous pollutants in coal-fired flue gas, pose a serious threat to human and ecological environment. Low temperature plasma synergistic catalyst has the characteristics of high reaction rate and no secondary pollution, so it has been paid more and more attention in the field of pollutant removal. In order to solve the problems such as the difficulty of denitrification at low temperature and the amount of catalyst used in industrial flue gas denitrification, a new method for NOx denitrification under low temperature window is proposed, in which no preoxidation and SCR can be rapidly denitrification by using low temperature plasma. Two ways of flue gas denitrification are studied in this paper: co-injection of oxygen active substances along surface discharge and co-discharge of corona discharge. In surface discharge oxygen active substance injection, clean air is injected into flue gas by surface discharge activation to oxidize part of no, while in corona discharge, The oxidation of no in flue gas occurs in the region of low temperature plasma. After low temperature plasma preoxidation, flue gas enters SCR reactor to complete denitrification. The main work and results of this study are as follows: (1) under the conditions of low temperature plasma generator optimization, The pretreatment effects of surface discharge oxygen active substance injection and corona discharge on NOx containing simulated flue gas were investigated respectively. O 3 is the main active substance for no oxidation by surface discharge oxygen active substance injection, but in the process of corona discharge oxidation, Both O and OH can participate in the oxidation of no. (2) the oxidation effect of no increases with the increase of voltage, the discharge length is 120mm, the injection flow rate is 75ml / min, and the flue gas temperature is 150 鈩，

本文编号：2071323