本文關(guān)鍵詞： 氣隙式膜蒸餾 真空膜蒸餾 過(guò)程優(yōu)化 多級(jí)能量回收 PTFE中空纖維膜　出處：《浙江大學(xué)》2016年博士論文　論文類(lèi)型：學(xué)位論文

【摘要】：膜蒸餾(MD)是正在發(fā)展中的一種新型膜技術(shù),在濃海水的淡化、含鹽水的濃縮、高鹽水的資源化處理等方面具有潛在應(yīng)用前景。本研究使用具有高孔隙率、高疏水特性PTFE中空纖維膜,設(shè)計(jì)并研制出滲透?jìng)?cè)負(fù)壓氣隙式膜蒸餾(V-AGMD)裝置。通過(guò)考察在負(fù)壓條件下的氣隙式膜蒸餾性能、在不同進(jìn)料溫度、流速、鹽濃度及冷凝液溫度條件下,V-AGMD和AGMD的運(yùn)行性能比較,以及通過(guò)正交試驗(yàn),進(jìn)行V-AGMD和AGMD的最優(yōu)運(yùn)行條件的考察等,所得結(jié)論如下：1.研究使用具有高孔隙率、高疏水性的PTFE中空纖維膜,并設(shè)計(jì)出新型的膜元件,此膜元件以多孔的中空纖維膜內(nèi)腔為待蒸發(fā)含鹽溶液的流道,用無(wú)孔的中空纖維內(nèi)腔為冷凝水的流道,用于構(gòu)建氣隙式膜蒸餾(AGMD)裝置,該裝置最大程度避免了膜的親水化現(xiàn)象發(fā)生,提高了膜元件使用壽命,為膜蒸餾過(guò)程的穩(wěn)定運(yùn)行、過(guò)程放大應(yīng)用奠定基礎(chǔ)。2.通過(guò)在滲透?jìng)?cè)輔加真空泵,所設(shè)計(jì)的負(fù)壓-氣隙式膜蒸餾裝置,用于膜蒸餾的蒸發(fā)實(shí)驗(yàn)。在進(jìn)料液溫度為80℃,鹽濃度為0.0253%,冷凝液溫度為20℃時(shí),隨進(jìn)料液流速由2增加到4 L/min, PR和η分別提高了15.25%和11.99%；在進(jìn)料液流速4 L/min,溫度50℃下,PF和GOR分別增加了24.96%和14.29%。該結(jié)果說(shuō)明有效地提升了AGMD的運(yùn)行性能。該試驗(yàn)結(jié)果表明,負(fù)壓-氣隙式膜蒸餾裝置能有效提高膜蒸餾過(guò)程的蒸發(fā)通量(PF)、熱效率(η),增益膜蒸餾的輸出比率(GOR)和性能比(PR)。3.通過(guò)正交實(shí)驗(yàn),獲得了不同操作條件下的最優(yōu)值。在進(jìn)料液溫度80℃,流速4 L/min,鹽濃度0.0253%。在此條件下,獲得了最高的PF和η。在進(jìn)料液溫度為70℃,流速2 L/min,鹽濃度1.6335%的條件下,獲得了AGMD過(guò)程最高的PR和GOR值。對(duì)于V-MEMD過(guò)程,在80℃、4 L/min、0.0253%的條件下獲得了最優(yōu)的PF、η和PR的值,而最優(yōu)的GOR則在80℃、2L/min、4.4825%的條件下獲得。進(jìn)一步設(shè)計(jì)出的具有多級(jí)能量回收功能的多效膜蒸餾(MEMD)裝置,用于對(duì)含鹽水溶液的膜蒸餾試驗(yàn)研究。試驗(yàn)結(jié)果表明：在高能耗的V-MEMD過(guò)程中輔加一級(jí)能量回收單元,能有效地提高V-MEMD的滲透流量并降低能耗；同時(shí)設(shè)計(jì)了具有三級(jí)能量回收單元的V-MEMD裝置,并進(jìn)行二種裝置運(yùn)行性能的比較,所得結(jié)論如下：1.所設(shè)計(jì)的具有一級(jí)能量回收單元的V-MEMD膜蒸餾過(guò)程,試驗(yàn)結(jié)果表明：PF, PR和GOR均有所提升,能耗(EC)/m3有所下降。與一級(jí)的V-MEMD過(guò)程相比,三級(jí)的V-MEMD過(guò)程,具有更高的運(yùn)行性能并降低能耗,有效地提高了V-MEMD過(guò)程的效率。2.對(duì)于具有三級(jí)能量回收單元的V-MEMD膜蒸餾過(guò)程,當(dāng)進(jìn)料流速400L/hr,滲透?jìng)?cè)真空度0.085MPa,進(jìn)料溫度80℃和鹽濃度為5.71%時(shí),其V-MEMD過(guò)程的PF, PR和GOR均有明顯提高。3.對(duì)于具有三級(jí)能量回收單元的V-MEMD膜蒸餾過(guò)程,當(dāng)進(jìn)料鹽濃度由5.71%上升到19.60%時(shí),V-MEMD過(guò)程對(duì)潛熱明顯提高,熱能回收率在17.32%與34.92%之間,電能回收率則提高到86.85%到91.50%之間。4.實(shí)驗(yàn)結(jié)果表明,與一級(jí)的V-MEMD過(guò)程相比,三級(jí)的V-MEMD過(guò)程有更高性能和更低的能耗,且引入能量回收過(guò)程有效地提高了V-MEMD過(guò)程的效率。
[Abstract]:Membrane distillation (MD) is a new type of membrane technology is being developed and in the desalination of sea water, concentrated salt, has potential application prospects of saline water resource treatment. This study has high porosity, high hydrophobic properties of PTFE hollow fiber membrane, designed and developed the permeate side pressure gas gap membrane distillation (V-AGMD) apparatus. Through the investigation of air gap membrane distillation performance under the condition of negative pressure, at different feed temperature, flow rate, salt concentration and condensate temperature conditions, comparison of performance of V-AGMD and AGMD, and through the orthogonal test, the optimum operating conditions for V-AGMD and AGMD inspection etc. the conclusions are as follows: 1., research with high porosity, high hydrophobic PTFE hollow fiber membrane, and the design of a new membrane element and the membrane element with hollow fiber porous cavity for passage to vaporize the salt solution, with empty holes Fiber lumen for condensate flow, for the construction of air gap membrane distillation (AGMD) device, the device maximum avoid the phenomenon of hydrophilic membrane, improve the service life of the membrane element, for the stable operation of membrane distillation process, amplification.2. lay the foundation by adding the permeate side vacuum pump, negative pressure the design of air gap membrane distillation device for evaporation experiment of membrane distillation. The feed liquid temperature is 80 DEG C, the concentration of salt is 0.0253%, the condensate temperature is 20 degrees centigrade with feed liquid velocity increased from 2 to 4 L/min, PR and N were increased by 15.25% and 11.99%; in the liquid flow rate was 4 L/min, the temperature of 50 DEG C, PF and GOR were increased by 24.96% and the results show that 14.29%. effectively improve the performance of AGMD. The test results show that the negative pressure air gap membrane distillation device can effectively improve the evaporation flux of membrane distillation (PF), thermal efficiency (ETA). Increase The output rate of benefit of membrane distillation (GOR) and the performance ratio (PR).3. by the orthogonal experiment, the optimal under different operating conditions. The value of feed liquid at 80 degrees Celsius temperature, flow rate of 4 L/min, the salt concentration of 0.0253%. under this condition, obtained the highest PF and ETA. In the feed temperature is 70 C, a flow rate of 2 L/min, the concentration of salt under the condition of 1.6335%, PR and GOR got the highest AGMD value for the V-MEMD process. In the process, 80 C, 4 L/min, 0.0253% under the condition of optimum PF, ETA and PR values, and the optimum GOR at 80 DEG C, 2L/min, 4.4825% conditions. Further designed with multistage energy recovery function of multi effect membrane distillation (MEMD) device for experimental research on membrane distillation of aqueous solution containing salt. The experimental results show that adding a level of energy recovery unit in the V-MEMD process, high energy consumption, can effectively improve the penetration of V-MEMD flow at the same time and reduce energy consumption; The V-MEMD device has a three energy recovery unit, and compared two kinds of device performance, the conclusions are as follows: 1. the design of a energy recovery unit V-MEMD membrane distillation process, the results show that PF, PR and GOR have improved, energy consumption (EC) decreased. Compared to /m3 with the V-MEMD level, V-MEMD level three, with higher operating performance and reduce energy consumption, improve the efficiency of.2. V-MEMD process for V-MEMD membrane distillation process with three levels of energy recovery unit, when the feed rate of 400L/hr penetration side vacuum 0.085MPa, feed temperature and 80 DEG C when salt concentration was 5.71%, the V-MEMD PF, PR and GOR were significantly increased in.3. V-MEMD membrane distillation process with three levels of energy recovery unit, when the feed concentration increased from 5.71% to 19.60%, V-MEMD of latent heat is obviously improved, the heat energy The recovery rate is between 17.32% and 34.92%, energy recovery rate is increased to 86.85% to 91.50%.4.. The experimental results show that compared with the V-MEMD level, V-MEMD level three has higher performance and lower power consumption, and the energy recovery process can effectively improve the efficiency of the V-MEMD process.

【學(xué)位授予單位】：浙江大學(xué)
【學(xué)位級(jí)別】：博士
【學(xué)位授予年份】：2016
【分類(lèi)號(hào)】：TQ028.8
，

本文編號(hào)：1496042