水泥炉窑烟气低温SCR脱硝成型催化剂优化研究

发布时间：2018-03-26 01:44

  本文选题：低温SCR脱硝　切入点：成型催化剂　出处：《浙江大学》2015年硕士论文

【摘要】：氮氧化物(NOx是主要的大气污染物,对环境造成了严重影响。选择性催化还原(SCR)技术是脱除固定源排放烟气中氮氧化物(NOx)的有效手段,对NOx污染的控制具有重要意义。我国水泥行业NOx排放量大,随着我国对NOx的排放标准日益提高,水泥行业NOx的进一步深度减排势在必行,但现有成熟有效的高温SCR技术对水泥炉窑的烟气适应性不佳。因此,开发一种适用于水泥炉窑尾气特点的低温SCR烟气脱硝技术具有非常重要的意义。目前,低温SCR成型催化剂在实际应用中仍面临低温条件下抗水和抗硫性差、易潮解以及机械强度不佳等问题。针对以上问题,本文对低温SCR成型催化剂的机械性能和抗性的提升展开优化研究,并在此基础上确立了低温SCR脱硝中试系统的设计方案。本文首先研究了催化剂的载体组分对抗水性和机械性能的影响。结果表明Ti02与分子筛对抗水性的影响相当,但Ti02对机械性能提升作用优于分子筛；在优化的Ti02添加量条件下,催化剂具有最优的抗水性和较强的机械性能。在此基础上,本文对催化剂的活性组分进行抗水和抗潮解正交实验分析,分别计算得到最优组合。经过综合极差比较和分析,选取5×5孔的综合最优组合催化剂。该催化剂在120℃,8%H20烟气条件下反应27h后,催化剂活性可以稳定在82%左右。此外,本文还考察了金属掺杂对成型催化剂在水、硫共存的低温烟气条件下脱销活性的影响。发现未掺杂的成型催化剂在同时含H2O和SO2的气氛中会快速失活,主要是由于活性组分和载体的硫酸化以及硫铵盐沉积堵塞孔道和覆盖活性位点所造成。而Co的掺入可以有效抑制成型催化剂表面的载体和活性组分的硫酸化以及硫铵盐的沉积,从而可以大大提高催化剂在同时含H2O和SO2气氛中的耐受性。最后,本文在实验室研究基础上,对水泥炉窑工况120℃,10000m3/h烟气量的中试工程进行了设计,中试系统的设计方案主要包括SCR脱硝反应器系统、烟道系统和氨供应、制备及喷射系统,并对该系统进行了相应的经济性评价。
[Abstract]:The selective catalytic reduction (SCR) technique is an effective method to remove no _ x from flue gas from stationary sources. It is of great significance to control NOx pollution. China's cement industry has a large amount of NOx emissions. With the increasing emission standard of NOx in China, it is imperative to further reduce the emission of NOx in cement industry. However, the existing mature and effective high temperature SCR technology is not suitable for the flue gas adaptability of cement kiln. Therefore, it is very important to develop a low temperature SCR flue gas denitrification technology suitable for the characteristics of cement kiln exhaust gas. The low temperature SCR forming catalyst is still faced with the problems of poor water and sulfur resistance, easy moisture solution and poor mechanical strength under low temperature conditions. In this paper, the mechanical properties and the improvement of resistance of low temperature SCR forming catalyst were studied. On this basis, the design scheme of low-temperature SCR denitrification pilot-scale system was established. Firstly, the effects of the support components of the catalyst on the water resistance and mechanical properties were studied. The results showed that the effects of Ti02 and molecular sieve on water resistance were equal to those of molecular sieve. However, the effect of Ti02 on mechanical performance is better than that of molecular sieve, and the catalyst has the best water resistance and strong mechanical property under the optimized Ti02 content. In this paper, the optimum combination of the active components of the catalyst was analyzed by orthogonal experiments of water resistance and moisture resistance, and the optimum combination was obtained by comprehensive range comparison and analysis. A 5 脳 5 pore composite catalyst was selected. After 27 h reaction at 120 鈩，

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