溴水的膜吸收性能研究

Study on membrane absorption performances of aqueous bromine solution

研究了溴水的膜吸收分离性能,并采用回归正交试验设计方法优化溴水膜吸收工艺条件.以NaOH溶液作为吸收剂,采用PVDF中空纤维膜,研究了吸收时间、溴水温度、吸收液浓度及其流速等操作条件对溴水膜吸收性能的影响.结果表明:溴的吸收率随吸收时间的增加而增大,溴水膜吸收过程进料温度与传质系数之间符合阿伦尼斯关系.吸收液侧NaOH的浓度从0.003mol/L增加至0.01mol/L时,传质系数从4.75×10-4 cm/s增至6.02×10-4cm/s,对应的膜通量从2.4×10-3 kg/(m2.h)增至3×10-3 kg/(m2.h).吸收液的流体动力学条件对于溴水膜吸收过程通量无显著影响.采用回归正交试验确定的PVDF膜溴水膜吸收分离最佳工艺为:当NaOH吸收溶液浓度为0.01mol/L,流量为2L/h时,浓度为220mg/L的溴水在进料温度为50℃、进料流速为22.24cm/s的条件下,膜吸收通量达到6.17×10-3kg/(m2.h).

The membrane absorption performances of aqueous bromine solution were studied in this work, and regression orthogonal experiment was adopted to develop the optimal technology. The effects ofabsorption time, aqueous bromine solution temperature, stripping solution concentration and flow rate and the other operating conditions on polyvinylidene fluoride （PVDF） hollow fiber membrane absorption performances of aqueous bromine solution were studied, NaOH was a stripping solution. The results showed that absorption rate of bromine increased with increasing absorption time and the feed temperature, and mass transfer coefficient was consistent with Arrhenius relationship. When the concentration of stripping solution was from 0. 003 mol/L to 0.01 mol/L, the mass transfer coefficient was from 4. 75 × 10 -4 cm/s tO 6.02 × 10-4 cm/s, and the membrane absorption flux was from 2.4 7（ 10-3kg/（m2 h） to 3× 10 3 kg/（m2 h） accordingly. The effect of fluid dynamic conditions of stripping side on membrane flux for membrane absorption was not obvious. The optimal technology conditions were developed by regression orthogonal experiment method= the stripping flow rate was 2 L/h and stripping concentration was 0. 01 mol/L; and the feed temperature was 50 ℃, the feed flow rate was 22.24 cm/s, and the feed concentration of aqueous bromine solution was 220 mg/L, the membrane absorption flux of queous bromine solution was 6. 177（10-3kg/（㎡· h）.