低浓度H₂S液相催化氧化动力学

【作者】 唐晓龙；

【导师】 宁平；

【作者基本信息】 昆明理工大学 ， 环境工程， 2003， 硕士

【摘要】 本研究中，以低浓度硫化氢气体为研究对象，在充分分析研究了以往的各种治理方法以及前期子课题的研究成果后，采用了一条以铁基离子作为主催化剂的较为简明的催化氧化净化路线，简化工艺的同时兼顾了硫磺回收。实验研究中，主要针对H₂S浓度在200～1500ppm之间，氧含量在0.5～21％的尾气进行了大量的动力学实验分析：随着原料气进气中H₂S浓度的提高，吸收过程的传质动力增强，在其他操作条件不变的情况下，吸收速率随之增大，实验数据对H₂S回归得吸收反应速率方程为：N_H2S=-1.49566+0.009284P_H2S，r=0.999043，r²=0.998087，因此可认为对H₂S是一级反应；在不同的吸收温度下，其吸收速率随原料气中H₂S浓度而变化的趋势基本一致，均随H₂S浓度的增加而增大，吸收反应在60℃时可达到较理想的净化效果；无论原料气中H₂S是高浓度还是低浓度，其吸收速率均随吸收液中Fe³⁺浓度的增加而增大，在原料气中H₂S浓度较低的情况下，吸收速率受Fe³⁺浓度的影响更大。当Fe³⁺浓度的增加到0.05mol／L时，吸收速率曲线的增长趋势均趋于平缓。因此，认为在此浓度下就可以满足反应需要了；在Fe³⁺离子浓度相同的条件下，pH值对吸收速率的影响较小，尤其在Fe³⁺离子浓度为0.05 mol／L时，吸收速率就已基本达到最大值。相对而言，H₂S含量低的气体比H₂S含量高的气体易受pH影响，pH控制在7～10的范围内时，反应速率及效率均随pH值的增大而升高，但变化幅度不大，能保持较稳定的状态；综合考虑，pH保持在9左右是较为理想的；在不同的试验温度下，In[P_H2S]-t呈现较好的线性关系，说明本实验中在20～80℃温度范围内，该反应对H₂S为一级反应：吸收反应的表观活化能Ea为24.814kJ／mol：当原料气中的氧含量在0.5％～10％之间时，随着氧含量的增加，吸收速率增长的趋势并不明显；而从10％到21％之间，吸收速率的增长幅度较为显著；在最佳操作条件下，用Fe³⁺作催化氧化剂，同时加入稳定剂，当尾气中氧含量仅为0.5％时，其净化效率可长时间维持在95％以上，且吸收液的硫容量大于4gH₂S／L吸收液；当吸收液硫容量达到饱和，可通入空气进行再生，同时可回收硫磺。 因此，本课题研究的液相催化氧化法对低浓度硫化氢尾气的治理及硫的回收利用具有重要的现实意义。更多还原

【Abstract】 In this paper, the study target is H2S gas in low concentration. After much study of all kinds of ways about H2S harnessing, which we know now, and based on the former researching of this project, we designed a compendious means. The main catalyzer is Fe3+, and after the redox of this reaction we can get sulfur (S).In my main dynamics experiments, H2S concentration is during 200 to 1500 ppm, the O2 content is 0.5~21%(volumetric proportion). After my analyzing, I found that: with the H2S concentration of the input gas increasing, the drive power of mass transfer is heightened. When the other experiment conditions are not changed, the reaction rate will also increase. From my experiment data, I got a reaction rate equation: NH2S = -1.49566 + 0.009284PH2S , r =0.999043, r2 =0.998087. So, I can consider this reaction is a first-degree reaction to H2S. Under the deferent reaction temperature, the change trend of reaction rate with the changing of H2S concentration in the input gas is almost same: all are heightened with the H2S increasing, and when the reaction temperature is 60℃, the reaction can be more better. Whether the concentration of H2S is low or high, the reaction rate is also heightened with the increasing of Fe3+ content. Especially under the low H2S concentration condition, the change trend is more obvious. When the Fe3+content increased to 0.05 mol/L, the change trend of reaction rate will be gentle. So, I can get that 0.05 mol/L of Fe3+content is better. When the other reaction conditions are same, pH influence is slight to reaction rate. Considering all conditions, pH=9 is better. In my experiment, the apparent activation energy (Ea) is 24.814 kJ/moL When the O2 content is during 0.5~10%( volumetric proportion) in the input gas, the reaction rate change trend is not obvious. But when O2 content changing from 10% to 21%, the increasing trend of reaction rate is more obvious.Under the best experiment conditions (Fe" is main catalyzer), and throw in a kind stabilizer, although the O2 content just is 0.5%, the purifying efficiency almost can be higher than 95% for a long time. When the absorbing liquid is saturated, we can input air to regenerate. At the same time, we can get sulfur after simply purifying.Therefore, this project study will be more useful to waste gas (H2S) harnessing.更多还原