超声波雾化处理模拟烟气中的SO2研究

Ultrasonic atomization simulated processing of SO2 in the flue gas

采用超声波雾化技术雾化Mn2＋吸收液,并利用雾滴中的Mn2＋催化氧化SO2,达到净化低浓度SO_2的目的。通过试验考察自然光照、雾化参数及工艺条件对超声雾化脱硫率的影响。结果表明,在有Mn2＋催化剂的条件下,自然光照对SO2在雾中的氧化贡献较小。在雾化液pH值4～6、气体流量0.3 L/min、雾化液体积120 m L、雾化功率40 W、Mn2＋浓度0.01 mol/L、温度35℃、SO2质量浓度1 500 mg/m3、氧体积分数15%的最佳反应条件下,脱硫率100%可维持510 min,脱硫率维持在80%以上的时间为880 min。

This paper is aimed to study on how to atomize the Mn2＋absorptive solution into fine droplets by using the ultrasonic atomization technology. To achieve the purpose,it would be necessary to increase the specific surface area of the absorbent and improve the gas-liquid contact effect so as to achieve the purpose of purifying the low content concentration of SO2 with the catalytic oxidation-ultrasonic atomization and synchronous absorption methods. Therefore,we have made experiments and investigations of the influence of the natural light,the atomization parameters and the processing conditions on the ultrasonic atomization and desulfurization. The results of our research show that,under the condition of Mn2＋catalyst,the natural light does not play a major role in the liquid-phase oxidation of SO2. However,when the atomization power reaches 40 W with the volume of atomized liquid being120 m L,it would be possible for the atomization rate to reach its maximal limit of 5 m L/min,with the desulfurization rate increasing up to 98. 7%. On the other hand,the optimalized reaction conditions for the ultrasonic atomization of absorbing low concentrated sulfur dioxide： gas flow rate should be 0. 3 L/min,whereas the atomization volume can go up to 120 m L,with the atomization power reaching 40 W and the Mn2＋concentration getting up to0. 01 mol/L under 35 ℃,so as for the SO2 mass concentration to teach 1 500 mg/m3 under the volume fraction of 15%. Furthermore,if the desulfurization rate can be maintained at 100% for the period of 510 minutes,the desulfurization rate can be maintained at a high rate of over 80% for the period of 880 minutes.What is more,if the p H value can be kept at 4-6,the concentration of HSO3- in the droplet water solution can be made to the highest rate,with the desulfurization rate increasing up to above90%. Nevertheless,if the pH value is below 4,the HSO-3 concentration in the droplet water solution may gradually be getting reduced,to quickly drop to 65. 4%. Therefore,in order to ensure better desulfurization effect,the p H value of the atomizing liquid should be maintained at least to 4-6. Thus,the experiment series we have laid out prove that under ultrasonic atomization,it would be possible to accelerate the catalytic oxidation rate of SO2,and,consequently,the reaction effect of the liquid-state catalytic oxidation of SO2 can be made effectively strengthened or enhanced.