稀硝酸作吸收剂的气态膜法回收废水中氨氮  

Supported Gas Membrane Process for Removal / Recovery of Ammonia from Wastewater by Using Dilute Nitric Acid as Absorbent

作　　者：郝兴阁[1] 王元喜[1] 李海庆[1] 秦英杰[1,2] 刘立强 崔东胜 

机构地区：[1]天津大学化工学院,天津300072 [2]天津凯铂能膜工程技术有限公司,天津300308

出　　处：《化学工业与工程》2015年第2期43-49,79,共8页Chemical Industry and Engineering

摘　　要：利用稀硝酸作吸收剂研究了基于聚四氟乙烯(PTFE)中空纤维微孔疏水膜的气态膜分离过程用于脱除/回收废水中氨氮并制取硝酸铵的可行性和长期操作稳定性。在相同的操作条件下对用PTFE、聚丙烯(PP)和聚偏氟乙烯(PVDF)制得的3种膜接触器的除氨性能进行了系统的比较,并研究了料液进口浓度、流速、温度条件对3种膜接触器传质性能的影响。实验数据表明中空纤维膜内径和壁厚是影响传质过程的最主要因素,且总传质系数K、膜侧传质系数kM、管程液相传质系数kL均随温度的升高而显著增加。室温下长期实验结果显示:PVDF膜运行7 d后发生严重泄漏,PP膜稳定运行20 d后传质系数显著下降,PTFE膜运行30 d时性能仍然保持稳定。表明具有良好耐硝酸氧化性的PTFE膜为气态膜法脱除/回收废水(或化工料液)中氨氮并制取硝酸铵的工业化应用提供了基本保障。In this study,the feasibility and long-term operational stability of PTFE hydrophobic microporous hollow fiber-based supported gas membrane process is demonstrated by using dilute nitric acid as absorbent solution to remove / recover ammonia from a wastewater stream. Under similar operation conditions,the separation performance of three kinds of membrane contactors made from PTFE,PP and PVDF were compared; the influence of inlet feed concentration,velocity and temperature on the mass transfer performance of PP,PVDF and PTFE contactors was also studied. Experimental results showed that the lumen-side diameter and wall thickness of the hollow fibers were the most dominant factor influencing the mass transfer process,and that,the overall mass transfer coefficient K,membrane mass transfer coefficient kM,lumen-side mass transfer coefficient kLincreased significantly with the increase of temperature.The long-term experimental results showed that the PVDF membrane contactor had a leakage problem after 7 days,the mass transfer coefficient of the PP membrane contactor had dropped notably after 20 days,while the PTFE membrane contactor still had a stable performance after running for 30 days. This study indicates that PTFE membrane has good resistance to nitric acid oxidation,it provides basic guarantee to remove / recover ammonia from wastewater（ or chemical feed solution） streams as a by-product of ammo-nium nitrate by using gas supported membrane separation process.

关 键 词：气态膜 聚四氟乙烯 硝酸 氧化性 操作稳定性 

分 类 号：TQ028.8[化学工程]