膜吸收法处理高浓度甲醛废气资源化技术研究

Treatment and resource utilization of high concentration formaldehyde with membrane absorption

采用疏水性中空纤维膜接触器,以NaHSO3为吸收液处理高浓度甲醛废气。研究了吸收液流量、吸收液温度、吸收液浓度、气体进口流量和气体进口浓度等因素对甲醛去除率和总传质系数的影响。结果表明,当吸收液流量为4.17×10-6m3/s,吸收液温度为60℃,甲醛进气流量为3.7×10-6m3/s,甲醛进气浓度为566 mg/m3时,甲醛出气浓度可低至2.8mg/m3,甲醛的去除率可达99.5%,总传质系数为4.46×10-5m/s。反应产物(ɑ-羟基磺酸钠)易分离,并可作为重要的有机合成原料或用于制备高纯甲醛而得到充分利用,NaHSO3溶液经适当稀释后仍可作为吸收液循环使用。表明膜吸收法可基本实现高浓度甲醛废气处理的资源化。

A new technique for treatment and resource utilization of high concentration formaldehyde with NaHSO3 by hydrophobic microporous hollow fiber membrane contactor was developed. Some important factors, such as the flux, temperature and concentration of the absorbent, the flux and concentration of the feed gas were thoroughly studied. Experimental results show that under the proper operation conditions, the absorbent flux is 4. 17×10^-6m^3/s, the temperature of the absorbent is 60 ℃ , the inlet flux and the inlet concentration of formalde- hyde are 3.7 ×10^-6m^3/s and 566 mg/m3 , respectively, the outlet concentration of formaldehyde is as low as 2.8 mg/m3 , the removal rate of formaldehyde reaches 99.5% and the overall mass transfer coefficient is 4.46 ×10^-5m/s. Moreover, the absorption product, CH2 （OH）SO3Na, can easily be separated and used as organic material or produce pure formaldehyde. The solution of NaHSO3can be recycled as absorbent only with proper dilution. The proposed technique may be a novel way to treat and utilize the high concentration formaldehyde as a resource.