【作者】 齐麟；

【导师】 吕晓龙；

【作者基本信息】 天津工业大学 ， 环境工程， 2008， 硕士

【摘要】 氨氮存在于许多工业废水中。其排入水体易形成富营养化污染,破坏水体环境。目前,传统处理工业含氨废水的方法主要是吹脱法,该方法有能耗高,不容易控制等缺点。膜吸收法具有投资少、能耗低、高效、使用方便和操作简单等特点,此外膜吸收法还有传质面积大的优点和没有雾沫夹带、液泛、沟流、鼓泡等现象发生,因此本文运用膜吸收法进行废水脱氨的研究。本文利用实验室自制的聚偏氟乙烯中空纤维膜,硫酸作吸收剂处理含氨废水,研究含氨废水处理过程。文中讨论了膜吸收法氨/水分离操作参数对传质的影响及其原因。实验结果表明膜吸收法对废水中的氨有较高的去除率(90%以上)。适当提高原料液的温度、流速和pH值都会大幅度提高氨的传质效率。吸收液侧硫酸的温度、流速和pH值对传质影响很小,相对于原料液侧各参数的影响可以忽略。而吸收液的pH值应小于4才能获得较好的吸收效果。此外,含氨废水走壳程时,可以利用这种操作模式所获得的较大的传质面积得到较含氨废水走管程时更高氨去除率,而不同的膜组件放置方式对膜吸收脱氨的效果并无明显影响。研究结果还表明了随着装填密度的增加,传质系数的变化趋势是先增大后减小。膜组件长度的增加提高了氨的去除率,传质系数却有所降低但程度较缓慢。随着中空纤维膜丝的壁厚从0.12mm增加到0.4mm,传质系数减小了69%,且两者成线性关系;而随着中空纤维膜丝的内径从0.6mm增加到1.2mm,传质系数增大了62.5%。中试现场实验结果表明,膜两侧流速、硫酸pH值、放置方式以及不同操作模式对传质的影响与实验室实验所得到的结论基本一致,在最佳操作条件下,氨的去除率达到95%。更多还原

【Abstract】 Ammonia, presenting in many industrial wastewaters, is a common pollutant to induce eutrophication of the receiving water body and to destroy water environment. Currently, the most widely used method for removing ammonia from industrial wastewater is air stripping which has several drawbacks such as high energy consumption and difficult in control, etc.Membrane absorption has a lot of advantages over traditional separation processes, such as high efficiency, low investment and energy consumption, convenient application and simple operation. In addition, membrane absorption also has some merits including surprisingly high interfacial area, absence of emulsions, no unloading at low flow rates and no flooding at high flow rates. Therefore, membrane absorption process was used for removal of ammonia from wastewater in this thesis.The laboratory-made hydrophobic microporous poly-vinylidene fluoride (PVDF) hollow fiber membrane was applied and sulfuric acid was used as the absorbent in the experiments. The influence of operation parameters in the process of ammonia/water separation using membrane adsorption was investigated experimentaly. The results indicated that increasing the circulation velocity, pH and temperature of the feed facilitated the mass transfer evidently and above 90% removal of ammonia from the wastewater was obtained. Whereas, the variation in operating factors of the absorbent had negligible effect on the efficiency of the membrane absorption process, except that the pH should be maintained below 4 for an effective ammonia removal. In addition, higher ammonia removal was obtained by applying outside-in module instead of inside-out module by utilizing the larger surface area of the former. Further, experimental results showed no obvious effect of the module orientation on the mass transfer.The effect of membrane and module properties were also discussed in this thesis based on the experimentalal data. The results indicated that the mass-transfer coefficient increased with the module packing density but followed by a decreasing trend. Longer modules favored the removal of ammonia but the mass transfer coefficient decreased due to the decreased mass transfer driving force along the longer modules. Moreover, mass-transfer coefficient was found to be linearly related to fiber thickness. As the fiber thickness increased from 0.12mm to 0.4mm, the mass-transfer coefficient decreased 69%. In addition, increasing the fiber inner diameter from 0.6mm to 1.2mm resulted in 62.5% enhancement in the mass-transfer coefficient.Finally, this paper introduced a field study of ammonia removal from an industrial wastewater using a pilot-scale membrane absorption system. The results in influence of liquid circulation velocities, pH of sulfuric acid, module orientation and different operating modes on ammonia removal and mass transfer confirmed the conclusion obtained from the laboratory study. The ammonia removal rate achieved 95% at the optimal operating condition.更多还原