本文選題：氣態(tài)膜 + 可逆型吸收劑�。� 參考：《天津大學(xué)》2016年碩士論文

【摘要】：氣態(tài)膜分離技術(shù)目前雖已得到廣泛研究并正在實(shí)現(xiàn)工業(yè)化應(yīng)用,但在處理特定料液體系時仍存在膜易被污染,長期操作穩(wěn)定性差、無法獲得理想目標(biāo)產(chǎn)物、吸收劑消耗大且產(chǎn)品無法回用等問題。聚四氟乙烯(PTFE)具有優(yōu)異的疏水性能,耐酸、堿和氧化性強(qiáng),是理想的微孔疏水膜制作材料。本研究針對海水提溴和廢水脫氨提出一種吸收劑可再生氣態(tài)膜過程,分別選用溴化鈉和磷酸二氫銨作可逆吸收劑;同為嚴(yán)格避免料液和吸收液泄露造成相互污染,分別采用PTFE中空纖維雙套型膜組件和單膜組件作為實(shí)驗(yàn)用膜接觸器,考察可逆氣態(tài)膜法濃海水提溴和廢水脫氨過程中料液流速、吸收液流速、溫度、料液進(jìn)口濃度和吸收液濃度對膜傳質(zhì)性能的影響及其操作穩(wěn)定性,運(yùn)用相應(yīng)的數(shù)學(xué)模型對傳質(zhì)過程進(jìn)行描述,同時驗(yàn)證吸收液蒸餾再生得到高濃溴水和濃氨水的可行性。濃海水提溴實(shí)驗(yàn)結(jié)果表明:逆流操作條件下,可逆氣態(tài)膜總傳質(zhì)系數(shù)K和提溴率η隨溫度的升高而增大,25℃時K可達(dá)1.10×10-5 m/s,η可達(dá)46.18%,多級膜組件串聯(lián)η可達(dá)95%以上;而料液流量和含溴量、吸收液流量和濃度對K影響不大。對吸收完成液進(jìn)行分析測定發(fā)現(xiàn),與料液溴含量相比溴素在吸收液中被富集了33倍以上。吸收完成液直接蒸餾后塔頂餾出液經(jīng)溴-水分離可得濃度75%以上的高濃溴水,這幾乎避免了酸堿消耗,蒸汽消耗也不到傳統(tǒng)提溴工藝過程的1/5,塔底溴化鈉溶液可重新用做提溴吸收液�？赡鏆鈶B(tài)膜長期提溴操作實(shí)驗(yàn)顯示PTFE膜具有良好的傳質(zhì)穩(wěn)定性和操作穩(wěn)定性。廢水脫氨實(shí)驗(yàn)結(jié)果表明:25℃時,傳統(tǒng)單膜組件總傳質(zhì)系數(shù)K可達(dá)1.37×10-5 m/s,單程氨氮脫除率η可達(dá)97.5%以上,新型雙膜組件總傳質(zhì)系數(shù)K可達(dá)9.6×10-6 m/s,單程氨氮脫除率η可達(dá)93.5%以上。雖然雙膜組件總傳質(zhì)系數(shù)小于單膜組件,但其組件構(gòu)型有利于保持料液和吸收液之間形成的負(fù)溫差,從而有效抑制滲透蒸餾現(xiàn)象,在低酸濃度時也可維持較高傳質(zhì)系數(shù),相比單膜組件其膜性能更加穩(wěn)定。可逆氣態(tài)膜過程可以把廢水氨氮值降至5 mg/L以下,吸收完成液經(jīng)蒸餾再生可得到濃度5%~18%的氨水和磷酸二氫銨溶液回用,蒸汽耗量不到單純蒸餾過程的1/3�？赡鏆鈶B(tài)膜長期脫氨操作實(shí)驗(yàn)顯示PTFE膜傳質(zhì)性能穩(wěn)定,能夠滿足此要求。可逆氣態(tài)膜過程在提取或脫除揮發(fā)性組分的同時能夠?qū)崿F(xiàn)揮發(fā)性組分和吸收劑的循環(huán)利用,本研究為PTFE可逆氣態(tài)膜法用于海水提溴和廢水脫氨工業(yè)化應(yīng)用提供了新思路和技術(shù)基礎(chǔ)。
[Abstract]:Although the gaseous membrane separation technology has been extensively studied and is being applied in industry at present, the membrane is still liable to be contaminated in the treatment of specific feed liquid system, and the long-term operation stability is poor, and the ideal target product can not be obtained.Absorbent consumption and products can not be reused and other problems.PTFEs are excellent hydrophobic, acid-resistant, alkali-resistant and oxidizing, and are ideal microporous hydrophobic films.In this study, an absorbent renewable gaseous membrane process was proposed for bromine extraction and wastewater deamination, in which sodium bromide and ammonium dihydrogen phosphate were used as reversible absorbers respectively.Using PTFE hollow fiber double nested membrane module and single membrane module as experimental membrane contactors, the flow rate of feed liquid, absorption liquid flow rate and temperature during bromine extraction from concentrated seawater by reversible gaseous membrane process and ammonia removal from wastewater were investigated.The effects of inlet concentration and absorbent concentration on the mass transfer properties of the membrane and its operational stability were studied. The mathematical model was used to describe the mass transfer process and the feasibility of distillation regeneration of the absorbent to produce high concentration bromine water and concentrated ammonia water was verified.The experimental results of bromine extraction in concentrated seawater show that the total mass transfer coefficient K and bromine extraction rate 畏 of reversible gaseous membrane can reach 1.10 脳 10 ~ (-5) m / s and 46.18 m / s at 25 鈩，

本文編號：1761802