海水淡化反渗透设计导则

®™TrademarkofTheDowChemicalCompany(“Dow”)oranaffiliatedcompanyofDow反渗透膜在海水淡化应用中的系统设计与运行®™TrademarkofTheDowChemicalCompany(“Dow”)oranaffiliatedcompanyofDow内容提要•取水方式•预处理系统•反渗透系统设计与选膜–通常的设计导则–ISD设计–海水除硼设计（Ashkelon）–7芯？8芯？9芯？®™TrademarkofTheDowChemicalCompany(“Dow”)oranaffiliatedcompanyofDowChlorineCoagulantFeCl3MMFPolishingFilterIntakePondFilteredWaterTankCartridgeFilterROUnitDrawBackTankHighPressurePumpSBSDisinfectionLimepHAdjustDistributionEnergyRecoveryDevice(ERD)ChlorineCoagulantFeCl3MMFPolishingFilterIntakePondFilteredWaterTankCartridgeFilterROUnitDrawBackTankHighPressurePumpSBSDisinfectionLimepHAdjustDistributionEnergyRecoveryDeviceERD)IntakeSystemPretreatmentSystemROSystemPost-treatmentMixBWwithSWBio-filterBoronResinNF-NForNF-ROHybridLargeDiameterROElementsCo-locationPowerStationHighRecoveryROSystem(SingleStageorBCS)DAFIntermittentChlorinationHighFloworThickerSpacerROElementsSubmergedMF/UFInfiltrationIntakeHighEfficiencyERDMF/UFBeachWellMixBWwithSWBio-filterBoronResinNF-NForNF-ROHybridLargeDiameterROElementsCo-locationPowerStationHighRecoveryROSystem(SingleStageorBCS)DAFIntermittentChlorinationHighFloworThickerSpacerROElementsSubmergedMF/UFInfiltrationIntakeHighEfficiencyERDMF/UFBeachWellOn-goingActivitiestoReduceCostsERD:EnergyRecoveryDevicesDAF:DissolvedAirFlotationBCS:BrineConversionSystem取水系统:膜法海水淡化系统的基本流程预处理系统:膜系统:后处理系统:®™TrademarkofTheDowChemicalCompany(“Dow”)oranaffiliatedcompanyofDow取水方式•敞开式取水–取水口距海岸100~300米远–水面以下约20米–海底以上20米–优点是取水费用低•深井取水–缺点是打深井费用较高–对大型海水淡化系统不适用–优点是取水水质很好，可以节省预处理部分的费用®™TrademarkofTheDowChemicalCompany(“Dow”)oranaffiliatedcompanyofDow预处理系统•传统预处理–絮凝沉淀+砂滤•膜法预处理–浸没式超滤–压力式超滤•其它方法–气浮（DAF）–活性碳过滤（ACF）–生物过滤（Bio-Filter）®™TrademarkofTheDowChemicalCompany(“Dow”)oranaffiliatedcompanyofDow根据取水水质选择预处理•深井取水（通常SDI2~3）–多介质过滤器–化学添加：少量的NaClO，SMBS；阻垢剂或酸（回收率50%）–保安过滤器•敞开取水（SDI一般在5~10之间）–NaClO消毒–FeCl3或其他絮凝剂，后接澄清池–多介质过滤器（之前通常二次投加NaClO），或UF–活性炭–SMBS–保安过滤器•结垢规律–45%回收率：无需考虑阻垢，S&DI0–45~55%回收率：CaCO3，加酸或阻垢剂–55%回收率：CaSO4，投加高端阻垢剂RawWaterAdjustedFeedConcentratepH7.67.67.77LangelierSaturationIndex0.450.451.12Stiff&DavisStabilityIndex-0.53-0.53-0.05®™TrademarkofTheDowChemicalCompany(“Dow”)oranaffiliatedcompanyofDowSWRO系统通常的设计导则®™TrademarkofTheDowChemicalCompany(“Dow”)oranaffiliatedcompanyofDow海水淡化系统段数设计•设计多少段？–回收率50%以下，通常只用一段（1995年前两段）–回收率50~60%，需要两段设计•两段设计，段间需要设增压泵•例外：采用ISD设计和FilmTec新型的大通量海水淡化膜，可以只用一段达到55~57%的回收率PumpRecyclePermeateConcentratePumpConcentratestage1Concentratestage2®™TrademarkofTheDowChemicalCompany(“Dow”)oranaffiliatedcompanyofDow系统回收率的演变20%30%40%50%60%70%Recovery(%)Before2000After2000FukuokaFukuokaTampaTampaCeuta(2003)Ceuta(2003)Ceuta(1998)Ceuta(1998)FujairahFujairahLarnakaLarnakaAddurAddur(1990)(1990)JeddahJeddahMedinaMedinaYanbuYanbuPointLisasPointLisas20%30%40%50%60%70%Recovery(%)Before2000After2000FukuokaFukuokaTampaTampaCeuta(2003)Ceuta(2003)Ceuta(1998)Ceuta(1998)FujairahFujairahLarnakaLarnakaAddurAddur(1990)(1990)JeddahJeddahMedinaMedinaYanbuYanbuPointLisasPointLisasDesignRecoveryisalsoaffectedbytemperature,finalwaterquaDesignRecoveryisalsoaffectedbytemperature,finalwaterquality,andetc.lity,andetc.PlantCapacity10,000m3/dayPlantCapacity10,000m3/day®™TrademarkofTheDowChemicalCompany(“Dow”)oranaffiliatedcompanyofDow级数设计•设计多少级？–与原水TDS，温度有关–与产水要求有关，TDS，硼脱除率–除了脱硼要求外，通常为一级–需结合通量，回收率等其他方面综合考虑•新概念–分流产水，压力容器两端均有产水管，前端产水直接应用，后端产水根据需要做二级处理PumpFeedWaterConcentrate(drain)Concentrate(sidestream)Permeatestage1(or“pass1”)Permeatestage2(or“pass2”)SeawaterHighpHBWROSWROBWROtreatedrearendpermeateBypass,frontendpermeateBlend®™TrademarkofTheDowChemicalCompany(“Dow”)oranaffiliatedcompanyofDow设计导则•设计缺陷导致污堵•高产水通量，高回收率，低浓水流量容易导致浓差极化和污染•ROSA自动设计报警•FilmTec的导则最严格FeedsourceROPermeateSeawaterWellorMF1OpenintakeFeedsiltdensityindexSDI1SDI3SDI5gfd21-258-127-10Averagesystemfluxl/m2h36-4313-2011-17Maximumelementrecovery%301513FeedsourceROPermeateSeawaterWellorMF1OpenintakeActiveMembraneAreaMaximumpermeateflowrate,gpd(m3/d)320ft2elements9,000(34)6,700(25)6,100(23)380ft2elements10,600(40)7,900(30)7,200(27)400ft2elements11,000(42)83007600FeedsourceROPermeateSeawaterWellorMF1OpenintakeElementtypeMinimumconcentrateflowrate2,gpm(m3/h)BWelements(400ft2and440ft2)10(2.3)SWelements10(2.3)13(3.0)15(3.4)ElementtypeActiveareaft2(m2)Maximumfeedflowrate2,gpm(m3/h)BWelements440(40.9)75(17)SWelements320(29.7)65(15)63(14)56(13)SWelements380(35.3)72(16)70(16)62(14)®™TrademarkofTheDowChemicalCompany(“Dow”)oranaffiliatedcompanyofDow典型设计•传统海水淡化–单支压力容器7~8支膜–一段，45%回收率–13~16lmh平均通量–SW30HRLE-400i–在最低温和最高温下分别设计–深井取水的FF为0.8，敞开取水的FF为0.7•低能耗–ISD设计，回收率50~55%，大通量膜元件•高污染海水–更低的平均通量，34mil流道的SW30HR-370元件•硼脱除要求–产水分流–高TDS产水做进一步处理，通常在高pH下采用BWRO，回收率85%®™TrademarkofTheDowChemicalCompany(“Dow”)oranaffiliatedcompanyofDow设计要点•控制好预处理是关键–控制pH，SDI，氧化还原电位–预先运行一个月再启动反渗透–预处理出问题要立即关闭反渗透系统。•反渗透部分–缓慢升压（2分钟）–防止产水回流导致背压破坏–坚持记录和标准化运行数据–出现问题及时清洗–停机时注意保存好膜元件®™TrademarkofTheDowChemicalCompany(“Dow”)oranaffiliatedcompanyofDow内部分段式设计内部分段式设计(ISD)(ISD)————降低反渗透海水淡化成本的降低反渗透海水淡化成本的新型设计概念新型设计概念®™TrademarkofTheDowChemicalCompany(“Dow”)oranaffiliatedcompanyofDow反渗透脱盐系统降低能耗的关键因素•更低