發(fā)布時間：2018-05-14 14:02

  本文選題：高效納濾 + 低壓反滲透　； 參考：《寧波大學(xué)》2015年碩士論文

【摘要】：在海水淡化系統(tǒng)中引入納濾(NF)技術(shù)是降低系統(tǒng)能耗的一個方向。然而,常規(guī)的納濾-反滲透海水淡化(NF-SWRO)系統(tǒng),由于第一級NF脫鹽率不夠高,往往導(dǎo)致其第二級RO的操作壓力大和整體的能耗過高。為了得到降低系統(tǒng)的設(shè)備要求和能耗的方法,本文提出并探討了高效納濾-低壓反滲透(HRNF-LPRO)的集成膜的新型海水淡化工藝,即第一級采用高脫鹽的納濾,第二級用適合苦咸水脫鹽的低壓反滲透。實(shí)驗(yàn)中選用NF90型納濾膜和BW30型低壓反滲透膜搭建小型實(shí)驗(yàn)裝置,對HRNF-LPRO工藝進(jìn)行了實(shí)驗(yàn)驗(yàn)證研究,并在實(shí)驗(yàn)的基礎(chǔ)上,使用陶氏反滲透設(shè)計(jì)軟件(ROSA)對HRNF-LPRO工藝進(jìn)行模擬,以驗(yàn)證HRNF-LPRO工藝應(yīng)用于大型海水淡化裝置的可行性和能耗問題。在NF脫鹽的實(shí)驗(yàn)研究中,膜的通量和截留性能,是受操作壓力、給水濃度、給水溫度等條件的影響。實(shí)驗(yàn)表明:操作壓力升高,NF90膜通量升高,溶質(zhì)截留率增加;給水濃度增加,膜通量大幅降低,溶解固體總量(TDS)和一價(jià)離子截留率也穩(wěn)定下降,對二價(jià)離子截留率的影響很小或下降不多;給水溫度增加,膜通量近似線性增加,TDS和一價(jià)離子截留率則穩(wěn)定下降,對二價(jià)離子截留率的影響很小或降幅不大。在常溫20°C、標(biāo)準(zhǔn)人工海水(34998ppm)給水和2.6MPa時,膜通量和TDS截留率分別可達(dá)到9.61L/m2·h和82.73%。LPRO的實(shí)驗(yàn)中,同樣考察操作壓力和給水濃度、溫度對BW30膜通量和截留性能的影響,實(shí)驗(yàn)表明:壓力升高,BW30的通量近似線性增加,給水濃度增加則通量穩(wěn)定下降;壓力增加,LPRO的截留率隨之增加,給水濃度增加時,截留率下降,低壓時降幅大,壓力增加后降幅小。在小規(guī)模的實(shí)驗(yàn)中,采用HRNF和LPRO聯(lián)用的兩極系統(tǒng),可脫除人工海水中99.84%的鹽分而淡化海水。HRNF-LPRO工藝能顯著降低第二級脫鹽操作壓力和產(chǎn)水能耗,即第二級脫鹽壓力從6.6MPa左右降至小于3.0 MPa,同時第一級操作壓力相差不大。在沒有使用變頻器和能量回收渦輪等節(jié)能裝置時能耗至少降低1k Wh/m3。在ROSA的模擬中,兩級分別采用1280支NF和480支LPRO膜元件,選用常溫和3.5%太平洋海水的典型給水條件,即20°C和34967.39ppm,模擬的最終產(chǎn)水TDS為231.17ppm,鹽截留率99.34%,淡水產(chǎn)量為44.65 m3/h,總回收率44.65%,在沒有使用變頻技術(shù)和渦輪能量回收裝置的條件下,綜合產(chǎn)水能耗為4.527k Wh/m3。采用能量回收裝置(90%回收),綜合產(chǎn)水能耗可降至3.264 k Wh/m3,低于現(xiàn)有的NF-SWRO工藝在采用了節(jié)能技術(shù)的能耗,3.7-5.8 k Wh/m3。HRNF-LPRO除了海水淡化工藝有顯著的節(jié)能優(yōu)勢外,其231.17ppm的產(chǎn)水TDS含量與NF-LPRO工藝差距不大,并且,與NF-SWRO工藝相比,都是采用的兩級脫鹽工藝,不會增加工藝的復(fù)雜性。因此,HRNF-LPRO是一種有發(fā)展前途的低能耗的海水淡化工藝。實(shí)驗(yàn)和模擬研究表明,HRNF-LPRO集成膜海水淡化工藝在降低設(shè)備要求和降低產(chǎn)水成本上有實(shí)際意義。
[Abstract]:The introduction of NFN in seawater desalination system is a direction to reduce the energy consumption of the system. However, the conventional nanofiltration reverse osmosis seawater desalination (NF-SWRO) system, because the first stage NF desalination rate is not high enough, often lead to the second stage RO operation pressure and the overall energy consumption is too high. In order to reduce the equipment requirement and energy consumption of the system, a new seawater desalination process with high efficiency nanofiltration and low pressure reverse osmosis (HRNF-LPROP) integrated membrane is proposed and discussed in this paper, that is, the first stage is high desalination nanofiltration. The second stage is suitable for desalting brackish water under low pressure reverse osmosis. In the experiment, NF90 nanofiltration membrane and BW30 low pressure reverse osmosis membrane were selected to build a small experimental device. The HRNF-LPRO process was tested and studied. On the basis of the experiment, Dow reverse osmosis design software was used to simulate the HRNF-LPRO process. In order to verify the feasibility and energy consumption of HRNF-LPRO process applied to large seawater desalination plant. In the experimental study of NF desalting, membrane flux and retention performance are affected by operating pressure, feed water concentration and feed water temperature. The experimental results show that the flux of NF90 increases with the increase of operating pressure, the retention rate of solute increases with the increase of feed water concentration, the flux of membrane decreases significantly, the total dissolved solids (TDSs) and the rejection rate of monovalent ions also decrease steadily. The effect on the bivalent ion rejection rate is very little or small, while the membrane flux increases linearly with the increase of feed water temperature, TDs and monovalent ion retention rate decrease steadily, and the effect on the bivalent ion rejection rate is very little or little. At 20 擄C at room temperature, the membrane flux and the TDS retention rate can reach 9.61L/m2 h and 82.73%.LPRO respectively under the conditions of standard artificial seawater water supply and 2.6MPa. The effects of operating pressure, feed water concentration and temperature on the membrane flux and retention performance of BW30 were also investigated. The experimental results show that the flux of BW30 increases linearly and the flux decreases steadily with the increase of feed water concentration, and the rejection rate of LPRO increases with the increase of pressure, and decreases with the increase of feed water concentration. The pressure increases after the decline is small. In a small scale experiment, the two-pole system combined with HRNF and LPRO can remove 99.84% of the salt in artificial seawater and desalinate seawater. HRNF-LPRO process can significantly reduce the second stage desalination operation pressure and water production energy consumption. The desalination pressure of the second stage is reduced from about 6.6MPa to less than 3. 0 MPA, and the first stage operation pressure is not different. Reduce energy consumption by at least 1 k / m 3 without the use of energy-efficient devices such as inverters and energy recovery turbines. In the simulation of ROSA, 1280 NF and 480 LPRO membrane elements were used in the two stages, and the typical water supply conditions of normal temperature and 3.5% Pacific water were selected. That is, 20 擄C and 34967.39 ppm, the simulated final water production TDS is 231.17 ppm, salt rejection rate is 99.34, fresh water output is 44.65 m3 / h, total recovery rate is 44.65 ppm, and without frequency conversion technology and turbine energy recovery device, the energy consumption of integrated water production is 4.527 k / m ~ (3). With 90% energy recovery unit, the comprehensive energy consumption of water production can be reduced to 3.264 kWhs / m3, which is lower than that of the existing NF-SWRO process. In addition to seawater desalination process, the energy consumption of 3.7-5.8k Wh/m3.HRNF-LPRO with energy saving technology has obvious advantages in energy saving. The water TDS content of 231.17ppm is not far from that of NF-LPRO process, and compared with NF-SWRO process, the two-stage desalination process is adopted, and the complexity of the process will not be increased. So HRNF-LPRO is a promising and low energy consumption desalination process. Experimental and simulation results show that HRNF-LPRO integrated membrane seawater desalination process has practical significance in reducing equipment requirements and water production cost.
【學(xué)位授予單位】：寧波大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：P747.5

【參考文獻(xiàn)】

相關(guān)期刊論文 前1條

1 尚偉娟;王曉琳;于養(yǎng)信;;基于電荷模型的荷電膜傳遞現(xiàn)象的研究進(jìn)展[J];化工學(xué)報(bào);2006年08期

，

本文編號：1888137