1229053 五、發明說明（1 ) 本發明係關於脫鹽方法及使用薄膜模組單元之脫鹽裝置 ，尤其是毫微濾膜（nanofiltration membrane)及逆滲透 薄膜，適當地使用以高回收率由海水製造淡水。 近年來例如以技術可達成由海水或高濃度鹼水獲得工業 用水及飮用水，且使用逆滲透之海水脫鹽方法已取代傳統 一般被進行的蒸發法。此逆滲透膜脫鹽法在各領域應用備 受期待，但需大量能量才能製造一些水及獲得高品質的水 〇 關於一般逆滲透海水脫鹽法，使用一高壓泵浦將海水加 壓至逆滲透薄膜模組至約6 . 0至6 . 5 MPa，因此獲得滲透 水（典型淡水），但在此條件中提供海水的淡水回收率（回 收％ )最高約爲40%。”淡水”應符合飮水標準，其含總溶解 鹽低於500 ppm，”回收率”爲藉由脫鹽裝置，每單位體積 之進料水製造淡水的體積比率，對於海水脫鹽而言，進料 水爲海水。 在海水脫鹽法中，淡水回收率直接關係著脫鹽成本，因 此較高的回收率較好。然而，事實上以一般逆滲透海水脫 鹽法增加回收率有所限制，即是爲了提高回收率，必須要 非常高之壓力，此導致的問題即是在模組的上游元件上， 以低鹽度之联1水使得海水滲透壓及驅動壓力（如有效壓 力）間的差異變得太大，在逆滲透膜上滲透水之量變得太 大，且包含在供應水中的異物成分（懸浮物質）迅速地阻塞 逆滲透膜，因此降低性能。 1229053 五、發明說明（2) 爲了解決上述問題，JPA 08 1 08048中揭示一種包含逆滲 透膜模組之多階段的配置，其中自第一階段逆滲透膜模組 的濃縮水之壓力被提高，且供應至第二階段逆滲透膜模組 ，而操時各階段之_效壓力並不..變大，因此提供高回收 率進行海水脫鹽而在逆滲透膜效能上避免阻塞之方法。根 據此安排，以在第一階段逆滲透膜模組之操作壓力約 6 . 5 MPa，及第二階段逆滲透膜模組約9 . 0 MPa爲例，估 計由3 . 5%鹽度之海水所獲得之淡水回收率爲ϋ%。 然而，即使當使用上述JPA 08 1 08048中揭示的方法， 淡水的回收率之上限約60%，此歸因於二個原因。第一， 提高淡水之回收率增加了逆滲透膜上濃縮海水之濃度，且 海水中所謂之積垢化合物（如硫酸鈣）之濃度在6 5 %回收率 時超過物質平衡的溶解限度，導致如水垢之積垢化合物沉 積在逆滲透膜上，因而阻塞薄膜。第二，在操作第二階段 逆滲透膜模組，因爲鹽度增加而增加滲透壓力使壓力更高 於 9 · 0 MPa 〇 因此，本發明陳述上述傳統技術的問題，且尋求提供脫 鹽方法及脫鹽裝置，以更高之回收率由海水製造淡水之適 當方式。 爲達此目的，本發明提供一種將水脫鹽之方法，其個別 的薄膜模組單元被設置複數階段（至少二個），其中自第一 階段膜模組單元之滲透水被供應至第二階段膜模組單元， 由此以獲得脫鹽滲透水。此方法包含：第一步驟將具有 -4- 1229053 五、發明說明（3 ) 3.0〜4.8重量％之總鹽濃度及200〜500 mg/1之鈣離子濃度 之進料水加工，其中至少一比例之進料水在第一階段膜模 組單元處理，以獲得滲透水且滲透水可視情況地混合額外 之進料水，因此進行於第一步驟之水因而具有進料水的 55〜95%之總鹽濃度及進料水的95%以下之鈣離子濃度；與 第二步驟提供第一步驟所製之水至第二階段膜模組單元’ 藉以獲得脫鹽水。 圖示之簡單說明： 本發明較佳之具體例現將以附圖爲參考加以說明，其中： 第一圖爲說明本發明之具體例的脫鹽裝置之流程圖。 第二圖爲詳細說明本發明之其他具體例的脫鹽裝置之流 程圖。 第三圖爲說明逆滲透膜模組單元之組態之流程圖，其爲 第二圖所顯示之本發明具體例之修正。 第四圖爲說明逆滲透膜模組單元之其他組態之流程圖， 其爲第二圖所顯示之本發明具體例之修正。 元件符號對照表： 在第一至四圖中，下列符號爲： 1 ： 海水流 2:淨化裝置 3 :毫微濾膜模組單元 3a:第一階段毫微濾膜模組元件 3b:第二階段毫微濾膜模組元件 1229053 五、發明說明（4) 4:壓力泵浦 5：進料水旁道管路 6:自毫微濾膜模組單元之滲透水流 7:混和器 8：供應至逆滲透膜模組單元之水流 9：逆滲透膜模組單元 9a:第一階段逆滲透膜模組元件 9b:第二階段逆滲透膜模組元件 10:高壓泵浦 11 :自逆滲透膜模組單元之滲透水流 1 2 :自逆毫微濾膜模組單元之濃縮廢水流 1 3 :自逆滲透膜模組單元之濃縮廢水流 14:能量回收裝置 1 5 :自第一階段逆滲透膜模組之濃縮水流 16:壓力提高裝置 17:積垢防止劑注入裝置 在根據本發明之脫鹽方法中，任何能夠調整鹽及鈣離子 濃度能力之薄膜，其足以爲配置在多階段之膜模組單元， 例如其包括逆滲透膜、離子交換膜及電荷鑲嵌膜（charge mosaic membrane)，但尤其是在第一階段適合使用之毫 微濾膜單元，其具有好的分離效率且在相對低壓下可被操 作。此外，適合於第二階段使用者爲逆滲透膜單元，其能 具高鹽移除百分比及提供大量的滲透水。 1229053 五、發明說明（5) 第一階段毫微濾膜模組單元其本身可具有配置於多數個 別次階段之多數（即至少兩個）模組元件，藉以將由第一 次階段毫微濾膜模組元件之濃縮水供應至第二階段毫微濾 膜模組元件，以獲得滲透水。相同地，逆滲透膜模組具有 配置於多數個別次階段之多數模組元件，其可使用作爲第 二階段逆滲透膜模組單元，其中將第一次階段逆滲透膜模 組元件之濃縮水供應至第二階段逆滲透膜模組元件，以獲 得滲透水。此特別優異的在供應濃縮水前，將第一次階段 逆滲透膜模組元件至第二階段逆滲透膜模組元件之濃縮水 壓力提昇以獲得滲透水。此外，第一次階段逆滲透膜模組 元件之操作壓力P ( η )與第二次階段逆滲透膜模組元件之 操作壓力P ( η+1 )間之關係較佳的在下式之範圍內： 1 · 15S P ( n + 1 ) /P ( n) S 1 ·8 在上述脫鹽方法中，在進行毫微過濾前將積垢抑制劑注 入供應至毫微濾膜模組單元之水中較佳，因爲當具有高鈣 離子移除率之毫微濾膜時，硫酸錦積垢的生成可被避免， 並可提昇回收率使用。 再者，較佳地以使用毫微過濾或超過濾進行過濾之過濾 水作爲供應水，因爲毫微米濾膜的污損所導致效率的退化 可被緩和。 關於本發明之脫鹽方法，以第一階段膜模組單元處理 30 - 1 00%，較佳地爲3 5 - 95%，更佳地爲40 - 90%之量的水， 然後混合仍未處理之進料水再供至第二階段膜模組單元。 1229053 五、發明說明（6) 而且根據本發明，脫鹽方法較佳的進行於來自第一階段 膜模組單元所獲得（基於水之供應量）之滲透水量百分比 65 - 95%範圍內，較佳地爲75-90%，更佳地爲由第二階段膜 模組單元所獲得（基於水之供應量）之該滲透水量百分比 70 - 85%範圍內。 此外，脫鹽方法較佳地進行於由第二階段膜模組單元[ 基於進料水（所謂之總回收率）之總量]之滲透水量百分 比在60- 80%範圍內，較佳地爲65 - 75%。 而且爲了實行上述脫鹽方法，本發明之脫鹽裝置包括： 至少第一及第二膜模組單元位於個別連續第一及第二階 段以供水滲透， 當該第一膜單元於第一階段時，毫微濾膜模組單元具有 膜模組及排泄管道因而將水滲透， 當該第二膜單元於第二階段時，逆滲透濾膜模組單元配 置於毫微濾膜模組單元之排泄管道以供水滲透； 一種轉移裝置，將供應至毫微濾膜模組單元之部分進料 水導引至該排泄管道，爲了繞過其膜模組；及（較佳地） 一種位於該排泄管道之裝置，在第二階段將該部分進料 水與在第一階段逆滲透膜模組單元之毫微濾膜模組所滲透 之水混合。 根據本發明較佳的裝置包括： 一種第一階段濾膜模組單元（毫微濾膜模組單元），較 佳地該單元在多數個別的次階段中具有多數模組元件， 1229053 五、發明說明（7) 一種第二階段濾膜模組單元作爲逆滲透膜模組單元’在 多數個別的次階段中亦具有多數模組元件，且配置於毫微 濾膜模組單元之滲透水管道中， 一種裝置將供應至毫微濾膜模組單元之部分進料水繞道 ，及（較佳地） 一種裝置將繞道的進料水與毫微濾膜模組單元之滲透水 混合，混合裝置被配置於逆滲透膜模組單元供應管道中。 在上述脫鹽裝置中，以第一階段毫微濾膜模組單元在個 別次階段具有多數模組元件爲較佳，且第二次階段毫微濾 膜模組元件被配置於第一次階段毫微濾膜模組元件之濃縮 水管道中。正如以下之說明，在各個別次階段中有至少一 個模組元件，但在任何次階段（尤其是第一次階段）可有 多數模組元件相互並行。此外，各第一次階段毫微濾膜模 組元件之總膜表面積S 1 ( η )與各第二次階段毫微濾膜模 組元件之總膜表面積S 1 ( η+ 1 )間之關係較佳的在下式之 範圍內： 1 . 5 ^ SI ( n ) / SI ( n + 1 ) ^ 5 相同地，第二階段逆滲透膜模組單元較佳的在個別次階 段具有多數模組元件，如此第二次階段逆滲透膜模組元件 被配置於第一次階段逆滲透膜模組元件之濃縮水管道中。 正如以下之說明，在各個別次階段中有至少一個模組元件 ，但在任何次階段（尤其是第一次階段）可有多數模組元 件相互並行。此外，各第一次階段逆滲透膜模組元件之總 1229053 五、發明說明（8) 膜表面積S2 ( η )與各第二次階段逆滲透膜模組元件之總 膜表面積S2 ( η+1 )間之關係較佳的在下式之範圍內： 1 .67^ S2 ( n) /S2 ( n+1 ) ^2.5 可提高濃縮水壓力之提高設備較佳的設置於最終逆滲透 膜元件之上游的逆滲透膜模組元件之濃縮水管道中，或各 多數逆滲透膜模組元件中。 此外，積垢抑制劑注入裝置較佳的配置於毫微濾膜模組 元件單元之供應進料水管道。 再者，微濾膜模組單元或超濾膜模組單元較佳的配置於 毫微濾膜模組元件單元之供應進料水管道。 本發明之具體例將以參考圖說明。本發明脫鹽裝置之具 體例以第1圖爲參考作說明，在第1圖中，脫鹽裝置包含 一澄淸裝置2以由進料水（流動線1 )之海水中移除懸浮 物質，毫微米濾膜模組單元3及壓力泵浦4 ’以供應進料 水至毫微米濾膜模組單元3，一迴路管道5以繞過供應進 料水至毫微米濾膜模組單元3之部分，混合裝置7以混合 來自毫微米濾膜模組單元之滲透水（流動線6)與迴路之 進料水，一逆滲透膜模組單元9將供應水（流動線8 )脫 鹽而所獲得之滲透水1 1，及一高壓泵浦1 〇以加壓供應水 至逆滲透膜模組單元9。在此具體例中，在各個別微米過 濾及逆滲透膜模組單元中，模組藉由單一模組元件提供。 在此處，就第一階段毫微濾膜模組單元3而言，所有的 供應進料水被進行毫微過濾製程，或是部分進料水被進行 -10- 1229053 五、發明說明（9) 毫微過濾製程’且進料水以迴路管道5繞過而經混合裝置 7與毫微濾膜之滲透水（流動線6)混合。此時，供應至 第二階段逆滲透膜模組單元9 (流動線8)之水的總鹽度 調整至進料水的55 - 90% ’而鈣離子濃度相同地調整至進料 水的95%或更少，其較佳的亦可將硫酸鹽離子濃度調整至 進料水的80%或更少，其海水中含量通常爲1 500-3500 mg/1 〇 控制供應水8之溶質濃度的理由如下，如果總鹽度在上 述範圍內，則第二階段逆滲透膜模組單元9之供應水8的 滲透壓會下降，逆滲透膜的操作壓力可設定較低’因此可 降低高壓泵浦1 0之電力消耗，且逆滲透膜上之壓力負載 亦可降低，其裝置的逆滲透膜的壽命可以延長，或在相同 操作壓力下以高回收率可獲得更多的滲透水。此外’如果 鈣離子濃度較範圍爲高，則硫酸鈣之沉澱會導致逆滲透薄 膜表面上積垢的生成而抑制了高回收率，因此以逆滲透膜 模組單元9之滲透水回收率可被改進。 毫微濾膜之形式或性能並無特別限制，任何毫微濾膜皆 可使用，只要所有供應進料水可被進行毫微濾膜法，或部 分進料水進行毫微濾膜法然後再混合繞過之進料水，之後 總鹽度爲進料水的55 - 90%，且鈣離子濃度爲進料水的95% 或更少。然而，較佳地使用如聚醯胺、聚六氫吡啶醯胺、 聚酯醯胺及交連水溶性乙烯系聚合物之物質所製造的毫微 濾膜。此外，關於膜構造，較佳地使用在至少一面具有細 -11- 1229053 五、發明說明（1〇) 微層之膜，其具有細微之孔洞且自膜內之細微層或朝向膜 另一層逐漸擴大其直徑（即不對稱膜），或在該具有不同 直徑之不對稱膜的細微層上形成具有非常細之分離功能層 。而且，當選則較佳之膜物質時，應該牢記在低壓下具有 生產較多量過濾水能力之膜較佳。因此，聚醯胺膜尤其在 所欲之滲透水量即化學抗性上較優異，而聚六氫吡啶醯胺 膜更爲優異。 毫微濾膜可被製成螺旋捲筒元件（將平面膜捲曲在收集 管柱上）、盤-框架元件（在雙面盤狀支撐盤上由平面膜 所形成之伸展元件積層在餘留空間，並以襯墊穿插在其中 )、管柱元件（使用管柱型膜）或孔洞纖維膜元件（孔洞 纖維被捆成束並裝入筒中，其以一或多數直線地收集並至 於抗壓容器中）。可使用上述任何形式之元件，但以使用 螺旋捲筒元件在所欲之操作性能上較佳。元件數量可根據 膜之效能任意地設置。如果使用螺旋捲筒元件，則在一模 組中元件數量較佳地連續設置4至6個。 再者，關於毫微濾膜元件之效能，在25 °C時總鹽度 3. 5%之過濾海水、操作壓力1.5 Mpa及回收率13%之條件 下，較佳的配置爲：鹽之移除率[TDS (總溶解鹽）：蒸發 殘渣]在30至80%範圍內，鈣離子之移除率在20至80%範 圍內，硫酸離子之移除率在9 5%或更高，且薄膜滲透流在 0.3至1.5 m3/ni2/d範圍內，因爲上述供應水（流動線6) 之總鹽度及鈣離子濃度範圍可輕易的達成。更佳地配置爲 -12- 1229053 五、發明說明（11) :鹽之移除率在35至70%範圍內，鈣離子之移除率在3〇 至60%範圍內，硫酸離子之移除率在97%或更高。 繞道的一定比例量之供應進料水可任意的設定，只要總 鹽度及鈣離子濃度範圍滿足上述之供應水（流動線8)， 且繞道的量較多而在毫微濾膜上進行的量少，則毫微過濾 所需之能量（電能）較少。然而在另一方面，如果繞道量 太大，則必須降低毫微濾膜滲透水之總鹽度，以便調整混 合後之總鹽度至上述範圍，導致必須提高毫微濾膜之操作 壓力或降低毫微濾膜滲透水之回收率，此並不經濟。所以 ，以毫微濾膜模組元件進行的較佳範圍在30至100%之進 料水，然後混合繞道之未處理進料水，而更佳的爲3 5至 9 5 %，最佳的爲4 0至9 0 %。 混合毫微濾膜滲透水與繞道之進料水的混合裝置7並不 特別限制，可例如提供於裝置中之混合桶，或如靜態混合 器之裝置。 根據第一階段毫微濾膜模組元件3之滲透水的回收率， 如果回收較低則所獲得滲透水之總鹽度低，但轉變成難以 獲得預估之水量，因此所有之回收並無增加。再者，如果 回收太高，則總回收可輕易的提升，但降低毫微濾膜滲透 水之鹽度變得困難，且連續地以第二階段逆滲透膜模組元 件9的回收並不能提升。因此，來自毫微濾膜模組元件3 之滲透水量的比例（依供應水之量）以65至95%的範圍內 較佳，以70至9 0%的範圍內更佳。 -13- 1229053 五、發明說明（12) 此外，爲了經濟地以預計的回收率操作第一階段毫微濾 膜模組元件3，較佳的使用如第二圖所示之配置，其中多 毫微濾膜模組元件被設置於次階段，以第一次階段毫微濾 膜模組元件3a供應濃縮水至第二次階段毫微濾膜模組元 件3b，因此而獲得滲透水。在第二圖之特別的具體例中， 倂置兩組此第一次階段毫微濾膜模組元件而供應濃縮水至 單一毫微濾膜模組元件。同時，各第一次階段毫微濾膜模 組元件3 a之總膜表面積S 1 ( η )與第二次階段毫微濾膜模組 元件3b之膜表面積Sl(n+1)之間的關係較佳的於下式（1) 之範圍內 1 .5^ SI ( n) /SI ( n+1 ) ^ 5 (1) 如上所述，設定的第一及第二次階段毫微濾膜模組元件 之膜面積能夠增加膜模組內之膜表面流速，所以導因於在 毫微濾膜表面上濃縮極化現象的過濾效能老化可被抑制， 藉以能保持低的滲透水總鹽度而具高度回收。以式（1 )所 示之外的範圍，過濾效可能老化，因爲可獲得之膜表面流 速並不夠充分，或是如果流速過快，則模組內壓力的損失 變的較大，且在此狀況下有模組可能毀損或損壞之危險。 關於毫微濾膜模組之次階段數目，膜表面流速在各階 段皆可設定，尤其是在較多數目上，毫微濾膜之過濾能力 很迅速的被證實，但多餘的增加數目會使元件組太複雜而 增加成本，因此並不經濟。根據這個觀點，實際上次階段 的數目爲2至4個。 -14- 1229053 五、發明說明（13) 在任何次單位中，多數的毫微濾膜模組元件可被並行設 置，且將水分開供應至其之間。如先前所說明，在第二圖 中第一次階段具有兩個此模組元件，且由其各自來的濃縮 水被導入第二次階段之單一模組元件。在各次階段中所有 數目之模組元件，來自較前次階段中的模組元件之滲透較 佳的繞過所有下游連續的模組元件，且由最後次階段模組 元件導入滲透流動線。 供應毫微濾膜模組單元3之壓力泵浦4並無特別限制， 不同形式之泵浦皆可使用，例如離心泵浦、渦卷泵浦、渦 輪泵浦及柱塞泵浦。 隨繼，在第二逆滲透膜模組單元9中，來自第一階段毫 微濾膜模組單元3之供應水（流動線8)以壓力泵浦1 0加 壓至預設壓力等於或大於滲透壓力，以逆滲透膜模組單元 脫鹽，及分離成爲滲透水（流動線1 1 )及濃縮廢水（流動 線 1 3 )。 任何的逆滲透膜皆可，只要水夠選擇性的滲透，且總鹽 之滲透可被避免。至於膜之結構，已使用非對稱膜較佳， 其至少一面具有細微層之膜，其自膜內之細微層朝向膜另 一層逐漸擴大其直徑，或以不同物質在該具有不同直徑之 不對稱膜的細微層上形成具有非常細之分離功能層。所使 用作爲膜之物質，包括醋酸纖維素聚合物、聚醯胺、聚酯 、聚亞醯胺、乙烯系聚合物及其他類似之聚合物質’所使 用較佳的典型的逆滲透膜包含醋酸纖維素或聚醯胺之具有 -15- 1229053 五、發明說明（14) 不對稱膜及聚醯胺或聚脲之活性層的化合物膜，具有芳族 聚醯胺之活性層的化合物膜。其中芳族聚醯胺之化合物薄 膜尤其較佳，因爲即使在改變水的特性下其穩定的效能亦 是明顯的，且如三鹵甲烷及類似之環境激素的有害物質可 適當的被移除。 當使用毫微濾膜時，由操作性的觀點較佳的使用逆滲透 膜型式，其可使用包括螺旋捲筒元件、盤-框架元件、管 柱元件或孔洞纖維膜元件，且即使可使用任何型式，但以 螺旋捲筒元件較佳。根據膜之效能，元件的數量可隨意的 設定，且如果使用螺旋捲筒元件，則在一壓力容器中提供 至單一模組的元件數量較佳地連續設置約4至6個。 此外，關於逆滲透膜元件之效能，在25 °C時總鹽度 3. 5%之過濾海水、操作壓力1 .5 Mpa及回收率13%之條件 下，較佳的配置爲鹽之移除率[TDS (總溶解固體）：蒸發 殘渣濃度]在9 9 %或以上，且薄膜滲透流在 〇 · 3至 1 . 5m3/m2/d範圍內，因爲滲透水的水質優異且滲透水可有 效率的獲得。 關於逆滲透膜模組單元9之滲透水回收率’較高的則爲 全面的回收（此爲値得追求的）’但如果太高’則必須之 操作壓力變高且所獲得之滲透水水質也變差’所以並不經 濟。此外，設定低的回收率改善了所獲得之滲透水水質’ 但所獲得之量少且總回收降低’因此並不經濟。故來自逆 滲透膜模組單元之滲透水量之比率（與供應水之量比）較 -16- 1229053 五、發明說明（彳5) 佳的在70至85%。 此外，爲了以預計之回收率有效率的操作逆滲透膜模組 單元9，較佳的使用如第二圖‘所示之配置，其中多數逆滲 透膜模組元件被設置於次階段，以第一次階段逆滲透膜模 組元件9a供應濃縮水至第二次階段逆滲透膜模組元件9b ，因此而獲得滲透水。在第二圖之特別的具體例中，倂置 兩組此第一次階段逆滲透膜模組元件而供應濃縮水至單一 第二次階段逆滲透膜模組元件。同時，各第一次階段逆滲 透膜模組元件9a之總膜表面積S2( η)與第二次階段逆滲透 膜模組元件9b之膜表面積S2(n+1)之間的關係較佳的於下 式（2 )之範圍內 1 .67^ S2 ( n) /S2 ( n+1 )^2.5 (2) 如上所述，設定的第一及第二次階段逆滲透膜模組元件 之膜面積能夠增加膜模組內之膜表面流速，所以導因於在 逆滲透膜表面上濃縮極化現象的過濾效能之老化可被抑制 ，藉以即使以高回收下仍能保持高的滲透水水質，且因濃 縮極化使有效壓力下降而減少滲透水量的降低可被抑制。 以式（2 )所示之外的範圍，過濾水質或所產生之水量可被 降低，因爲可獲得之膜表面流速並不夠充分，或是如果流 速過快，則模組內壓力的損失變的太大，且在此狀況下有 模組可能毀損或損壞之危險。 關於逆滲透膜模組之次階段數目’膜表面流速在各階段 皆可設定，尤其是在較多數目上’逆滲透膜之過濾能力很 -17- 1229053 五、發明說明（16) 迅速的被證實，但多餘的增加數乱會使元件組太複雜而增 加成本，因此並不經濟。根據這個觀點，實際上次階段的 數目爲2至4個。 在任何次單位中，多數的逆滲透膜模組元件可被並行設 置，且將水分開供應至其之間。如在第二圖中第一次階段 具有兩個此模組元件，且由其各自來的濃縮水被導入第二 次階段之單一模組元件。在各次階段中所有數目之模組元 件，來自較前次階段中的模組元件之滲透較佳的繞過所有 下游連續的模組元件，且由最後次階段模組元件導入滲透 流動線。 關於在各階段逆滲透膜模組元件之操作壓力，藉由僅以 來自第一階段逆滲透膜模組元件所供應之水的壓力來操作 第二次階段逆滲透膜模組元件，滲透水可在充分有效率方 法下獲得，而並不再提供分離增壓裝置，但如第3圖所示 ，在逆滲透模組單元之第一次階段逆滲透膜模組元件9a 與第二次階段逆滲透膜模組元件9b間的濃縮水管道1 5中 ，以增壓裝置1 6將其中之濃縮水壓力增壓，以提高操作 壓力藉以供應濃縮水至第二次階段逆滲透膜模組元件以獲 得滲透水，此爲較佳的。因爲在各次階段中的逆滲透膜模 組元件之分離效率進一步的被提升，可有效率的獲得滲透 水。同時，於在各次階段的操作壓力，第一次階段逆滲透 膜模組元件之操作壓力P ( η )與第二次階段逆滲透膜模組 元件之操作壓力Ρ ( η+ 1 )間之關係較佳的在下式之範圍內 -18- 1229053 五、發明說明（η) 1 . 15^ P ( n+l ) /P ( n) ^1.8 此外，若以海水總鹽度爲3. 5%爲例，在逆滲透膜模組 40%回收下5 . 5至7 . 〇 MPa之操作壓力是必須的，而在60% 爲8· 5至1〇.〇 MPa。但在本發明中，被供應至逆滲透膜模 組之海水總鹽度經由毫微濾膜已被降至2 . 0至3 . 1 %，因 此在相同的回收下操作壓力可被設定低於一般者。特殊的 操作壓力適當的根據進料水之濃度、毫微濾膜之模組單元 3中總鹽度之調整、及逆滲透膜模組單元9加以選擇；然 而’例如若以具有總鹽度爲3.5%之海水以毫微濾膜模組單 元3調整，以具有總鹽度2 . 5%之海水供應至逆滲透膜模組 單元9作爲80%之回收，則操作壓力則被設定於8.0至 9.5 MPa之範圍內。 逆滲透膜模組單元9之高壓泵浦10可使用各種不同形 式之泵浦，例如離心泵浦、渦卷泵浦、渦輪泵浦及柱塞泵 浦。再者，關於增壓裝置1 6，如果提供多數逆滲透膜模組 次階段，且加壓來自第一次階段逆滲透膜模組元件之逆滲 透水壓力，則可使用如離心泵浦或渦卷泵浦之壓力泵浦。 此外，如上所述，逆滲透膜模組單元9之操作壓力極高 (約8 · 0至9 · 5 MPa )，且自單元中所排放出之濃縮水亦 具有約相同之壓力。因此，如第二及三圖所示，能量回收 裝置1 4較佳的設置以回收滲透水之壓力能量。只要能夠 達到能源回收之方法皆可使用，如回流泵浦、裴頓渦輪（ -19- 1229053 五、發明說明（18) Pelton turbine)、輪機充電機及壓力轉化器等任何方法 〇 回收能量的其他方法爲一種如第4圖所示配置，其中於 在多數逆滲透膜模組次階段之第一次階段設置能量回收裝 置1 4以增壓濃縮水之壓力。在此情況下，輪機充電機使 用作爲能量回收裝置（揭示於如JPA0 1 294903 )，其較佳 是因爲裝置之外形及操作方法簡便。 裝置較佳的較佳的操作是以經由逆滲透膜模組單元9所 獲得之滲透水最終量以進料水量之百分比表示，在60〜80% 之範圍內，更佳的爲65〜75%。 目前在毫微濾膜及逆滲透膜之滲透水方面，提高的鹽度 之濃縮經由增加鈣離子及硫酸離子（其爲積垢成分）的濃 度同時發生，此時如果兩離子之濃度皆增加，則如硫酸鈣 積垢會沉澱於膜表面。吾人經實驗證實引起硫酸鈣積垢沉 澱之最小離子濃度爲鈣離子約1 200 mg/1及硫酸離子約 2900mg/I，且只要兩個離子濃度不要同時超過上述之値並 不會有硫酸15積垢沉澱於膜表面之危險。 根據本發明，可以調整毫微濾膜模組單元之操作條件及 與繞道之進料水的混合比率，且如回收之逆滲透膜模組單 元之操作條件可被設定在硫酸鈣積垢之沉澱不會發生於逆 滲透膜表面，因此不會有任何關於積垢沉澱於逆滲透膜模 組的問題。另一方面，在毫微濾膜模組方面，如上所述根 據所使用毫微濾膜之性能在鈣離子移除百分比上有很大的 -20- 1229053 五、發明說明（19) 差異，所以，當使用鈣離子移除百分比相對低之毫微濾膜 ，在毫微濾膜表面的積垢沉澱並不容易發生，因爲在毫微 濾膜之濃縮方面，鈣離子濃度並不輕易的變高，即使如果 在高的回收率下。但使用鈣離子移除百分比高之毫微濾膜 ，則有在毫微濾膜表面之濃縮水方面鈣離子濃度變高及發 生硫酸鈣積垢沉澱之危險。因此當使用該鈣離子移除百分 比高之毫微濾膜時，毫微濾膜模組單元較佳的添加積垢沉 澱抑制劑至供應進料水，然後再操作裝置。 關於注入積垢沉澱抑制劑之位置，在與積垢沉澱抑制劑 直接注入進料水以使積垢沉澱抑制劑亦導入迴路側相互比 較下，如果在接於分裂迴路後的毫微濾膜模組單元（如第 1圖中所示之參考數1 7 )之前直接地注入，則只需要添加 較少的積垢沉澱抑制劑，故此配置較佳。 關於積垢沉澱抑制劑之類型，只要硫酸鈣積垢沉澱能夠 被防止，任何類型皆可使用。然而，由價格及產生預期效 果的觀點，較佳的使用如六偏磷酸鈉（SHMP)之聚磷酸鹽 、如以乙二胺四乙酸（EDTA )爲代表之有機單體、如聚丙 烯酸或聚藻朊酸之有機聚合物。 關於積垢沉澱抑制劑注入方法，在方式上並無特別限制 ’只要以定量注入供應水，但以使用隔膜泵浦或齒輪泵浦 而注入壓力泵浦之吸入部位以供毫微濾膜模組較佳，因爲 可精確地即有效率地進行注入。 再者，雖然本發明可被供應各種形式之水，如河水、湖 -21 - 1229053 五、發明說明（2〇) 及沼澤之水、地下水及工業廢水’但以加工海水或高濃度 鹹水較佳，因爲在如高回收及經濟效率之特性上可被顯示 出來。 污泥密度指數（SDI値）係爲一種表示進料水雜質之指 數，較佳控制在4以下。以具有低於4之SDI値的水而言 ，幾乎不會有懸浮物質吸附於毫微濾膜或逆滲透膜之污損 ，因此裝置可在穩定的方式下操作很長一段時間。必須注 意的是SDI値表示水中瞬間懸浮物質之濃度，且由（1-T0/T15) X 100/15表示，其中T。表示當以0.2 MPa過濾壓 力下使用0.45/z m微濾膜進行時，過濾前500 ml樣品水 所需之時間，而T15表示在相同條件下，在^後隨繼過濾 15之後過濾其他500 ml樣品水所需之時間，不具懸浮物 質總產量之水爲0，且最多雜質之水的最大値爲6 . 67。 控制進料水SDI値低於4之淨化裝置2並不以其方法加 以特別限制，但較佳地使用如一般所使用之冷凝沉積或冷 凝砂濾法、磨光過濾或其他過濾法。再者，使用微濾膜模 組或超濾膜模組進行過濾更佳，因爲因懸浮物質、微生物 等在毫微濾膜模組及逆滲透膜模組上的污染可被減低，可 穩定操作及膜元件之壽命可以延長。則微濾膜具有範圍在 0 . 1至1 // m的細微孔洞之分離膜，用以滲透水及溶解成分 但移除懸浮物質、細微粒子及微生物、0 . 1 // m或更大者。 超濾膜具有範圍在0.01至0 . 1 # m的細微孔洞之分離膜， 用以滲透水及溶解成分但移除有機聚合物、細微粒子、病 -22- 1229053 五、發明說明（21) 毒及微生物、0 · 1 // m或更大者。關於本發明，微濾膜及超 濾膜可以任何物質構成，且可爲任何形式，只要膜具有以 上功能或細微孔洞。在其他情況，可使用作爲膜之物質的 實例包括有機聚合物膜，如聚丙烯腈、聚碾、聚乙烯、聚 丙烯、聚醚碾及醋酸纖維素聚亞醯胺；及陶瓷濾膜，如礬 土、氧化鉻及礬土 -矽石。其形式可爲管狀膜，如中空纖 維、管式或單塊狀，或平面膜，如螺旋型或平板-框狀。 此外，根據以上使用過濾方法之配置，如果是使用200m 以上深度之深海水，或使用海床之砂作爲濾器所得之水， 則並不需要過濾過程，該配置亦爲較佳的。 本發明較佳的具體@現以下列實例及比較例作爲參考更 具體加以描述。 ' 實例1 -1 0及比較例1 - 5 毫微濾膜之功效藉由回收率及操作壓力加以評估。如第 1圖所示之具有連續裝配二階段膜膜組之脫鹽裝置係使用 毫微濾膜模組及逆滲透膜模組構成。 就毫微濾膜模組而言，裝配直徑4吋具有7 . 0 m2膜面積 之元件，且將4至6個該元件至於壓力槽中以供作膜模組 ，所使用之毫微濾膜模組的總脫鹽力約62%、鈣離子移除 百分率約53%、硫酸離子移除百分率約97%，且pH 6.5、 總鹽度約3.5%、鈣離子濃度約350 mg/I、及硫酸離子濃 度約2100 mg/1之25t海水於操作壓力1 .5 MPa及13%回 收之過濾條件下，產生約4 . 9 m3 / d之水。此外，就逆滲 -23- 1229053 五、發明說明（22) 透膜模組而言，以毫微濾膜相同方法裝配直徑4吋具有 7 . 0 m2膜面積之元件，且將6至8個該元件至於壓力槽中 以供作膜模組，所使用之逆滲透膜模組的總脫鹽力約 99.7%，且總鹽度約3.5%、pH 6.5之25°C海水於操作壓力 5.5 MPa及13%回收之過濾條件下，產生約5.0 m3/d之水 。以微濾膜元件調整海水之SDI値爲2 . 5至3 . 5範圍內而 供應至此脫鹽裝置，而海水具有總鹽度約3.5%、鈣離子濃 度約350 mg/I、及硫酸離子濃度約2100 mg/I。海水以毫 微濾膜模組單元加工，使用過濾水或混有繞道之海水，並 在表1之實例1-10所示之操作條件下，供至逆滲透膜模 組單元之水依表1所示之鹽度及鈣離子濃度製備並供至逆 滲透膜模組。另一方面，關於比較例，使用完全與實例相 同之脫鹽裝置，在本發明操作條件範圍以外下進行，如表 1比較例1 · 5所示，且在操作24小時後測量性能。 根據結果，當實例之步驟容許逆滲透膜模組以相當低的 操作壓力及高的回收操作時，獲得具高品質之淡水。這些 比較例則存有如因積垢的生成而導致之不充分的回收、在 與實例相同之回收下需要較高的操作壓力才能獲得淡水、 或是在與實例相同之逆滲透膜操作壓力下，相比較下僅能 允需以較低之回收操作。 此外，毫微濾膜及逆滲透膜之濃縮水鈣離子濃度以規定 於〗IS K01 01之ICP發射分光分析，硫酸離子濃度以亦規 定於HS K0101之離子色層分析法分析，以濃縮水顯示實1229053 V. Description of the invention (1) The present invention relates to a desalination method and a desalination device using a membrane module unit, especially a nanofiltration membrane and a reverse osmosis membrane, suitably used to produce fresh water from seawater with a high recovery rate . In recent years, for example, technology can be used to obtain industrial water and tritium water from seawater or high-concentration alkaline water, and seawater desalination methods using reverse osmosis have replaced traditional evaporation methods that are generally performed. The application of this reverse osmosis membrane desalination method is highly anticipated in various fields, but it requires a lot of energy to produce some water and obtain high quality water. About the general reverse osmosis seawater desalination method, a high pressure pump is used to pressurize the seawater to the reverse osmosis membrane. Module to about 6. 0 to 6. 5 MPa, so osmotic water (typically fresh water) is obtained, but the fresh water recovery rate (% recovery) that provides seawater in this condition is up to about 40%. “Fresh water” should meet the standard of decanted water, which contains less than 500 ppm of total dissolved salts. The “recovery rate” is the volume ratio of fresh water produced per unit volume of feed water by a desalination device. For seawater desalination, the feed Water is sea water. In seawater desalination, the freshwater recovery rate is directly related to the cost of desalination, so higher recovery rates are better. However, in fact, the general reverse osmosis seawater desalination method has some limitations in increasing the recovery rate, that is, in order to improve the recovery rate, a very high pressure must be used. The problem caused by this is the low salinity on the upstream components of the module Zhilian 1 water makes the difference between seawater osmotic pressure and driving pressure (such as effective pressure) become too large, the amount of osmotic water on the reverse osmosis membrane becomes too large, and the foreign matter components (suspended matter) contained in the supply water quickly Ground block the reverse osmosis membrane, thus reducing performance. 1229053 V. Description of the invention (2) In order to solve the above problems, JPA 08 1 08048 discloses a multi-stage configuration including a reverse osmosis membrane module, in which the pressure of concentrated water from the first stage reverse osmosis membrane module is increased, And supply to the second stage reverse osmosis membrane module, and the effective pressure of each stage during operation is not. . Larger, thus providing a method for high-recovery desalination of seawater while avoiding blockages in the performance of reverse osmosis membranes. Based on this arrangement, the operating pressure of the reverse osmosis membrane module in the first stage is about 6. 5 MPa, and the second stage reverse osmosis membrane module is about 9. 0 MPa as an example, estimated by 3. The fresh water recovery rate of 5% salinity seawater is ϋ%. However, even when the method disclosed in the above JPA 08 1 08048 is used, the upper limit of the recovery rate of fresh water is about 60%, which is attributed to two reasons. First, increasing the recovery rate of fresh water increases the concentration of concentrated seawater on the reverse osmosis membrane, and the concentration of so-called scale compounds (such as calcium sulfate) in the seawater exceeds the solubility limit of the material balance at a 65% recovery rate, resulting in Scale deposit compounds are deposited on the reverse osmosis membrane, thereby blocking the membrane. Secondly, in the second stage of the operation of the reverse osmosis membrane module, increasing the osmotic pressure due to the increase in salinity makes the pressure higher than 9 · 0 MPa. Therefore, the present invention addresses the problems of the conventional technology described above, and seeks to provide a desalination method and desalination. Appropriate way to produce fresh water from seawater with higher recovery. To achieve this, the present invention provides a method for desalination of water. The individual membrane module units are provided with a plurality of stages (at least two), and the permeated water from the membrane module units of the first stage is supplied to the second stage. Membrane module unit, thereby obtaining desalted permeate water. This method includes: the first step will have -4- 1229053 5. Invention Description (3) 3. 0 ~ 4. Processing of feed water with a total salt concentration of 8% by weight and a calcium ion concentration of 200 ~ 500 mg / 1, at least a proportion of the feed water is processed in the first-stage membrane module unit to obtain permeate water and the permeate water is visible The additional feed water is occasionally mixed, so the water performed in the first step thus has a total salt concentration of 55 to 95% of the feed water and a calcium ion concentration of less than 95% of the feed water; and the second step provides the first The water produced in one step is passed to the second-stage membrane module unit to obtain desalinated water. Brief description of the drawings: A preferred specific example of the present invention will now be described with reference to the drawings, wherein: The first figure is a flowchart illustrating a desalination device of a specific example of the present invention. The second figure is a flowchart illustrating a desalination apparatus according to another specific example of the present invention in detail. The third figure is a flowchart illustrating the configuration of the reverse osmosis membrane module unit, which is a modification of the specific example of the present invention shown in the second figure. The fourth figure is a flowchart illustrating other configurations of the reverse osmosis membrane module unit, which is a modification of the specific example of the present invention shown in the second figure. Component symbol comparison table: In the first to fourth figures, the following symbols are: 1: Seawater flow 2: Purification device 3: Nanofiltration membrane module unit 3a: First stage nanofiltration membrane module element 3b: Second Phase nanofiltration membrane module element 1229053 V. Description of the invention (4) 4: Pressure pump 5: Feed water bypass pipe 6: Permeate water flow from the nanofiltration membrane module unit 7: Mixer 8: Supply Water flow to reverse osmosis membrane module unit 9: reverse osmosis membrane module unit 9a: first stage reverse osmosis membrane module element 9b: second stage reverse osmosis membrane module element 10: high pressure pump 11: self-reverse osmosis membrane Permeate water flow of module unit 1 2: Concentrated wastewater flow of self-reverse nanofiltration membrane module unit 1 3: Concentrated wastewater flow of self-reverse osmosis membrane module unit 14: Energy recovery device 1 5: Reverse osmosis from the first stage Concentrated water flow of membrane module 16: Pressure increasing device 17: Fouling preventive agent injection device In the desalination method according to the present invention, any film capable of adjusting the salt and calcium ion concentration capability is sufficient for a film mold configured in multiple stages Group unit, for example, it includes reverse osmosis membrane, ion exchange membrane and charge mosaic (Charge mosaic membrane), but especially suitable for use in the first stage of milli microfiltration unit, having a good separation efficiency at relatively low pressure and can be operated. In addition, suitable for the second-stage user is a reverse osmosis membrane unit, which can have a high percentage of salt removal and provide a large amount of permeate water. 1229053 V. Description of the invention (5) The first stage nanofiltration membrane module unit may have a majority (ie at least two) module elements arranged in most individual substages, so that the first stage nanofiltration membrane module The concentrated water of the module element is supplied to the second-stage nanofiltration membrane module element to obtain permeate water. Similarly, the reverse osmosis membrane module has most module elements arranged in most individual sub-stages, which can be used as the second stage reverse osmosis membrane module unit, in which concentrated water of the first stage reverse osmosis membrane module element is used. Supply to the second stage reverse osmosis membrane module element to obtain permeate water. This is particularly excellent in increasing the pressure of the concentrated water from the first stage reverse osmosis membrane module element to the second stage reverse osmosis membrane module element to obtain the permeate water before supplying concentrated water. In addition, the relationship between the operating pressure P (η) of the reverse osmosis membrane module element in the first stage and the operating pressure P (η + 1) of the reverse osmosis membrane module element in the second stage is better within the range of the following formula : 1 · 15S P (n + 1) / P (n) S 1 · 8 In the desalination method described above, it is better to inject the scale inhibitor into the water supplied to the nanofiltration membrane module unit before performing the nanofiltration. Because when the nanofiltration membrane has a high calcium ion removal rate, the formation of sulfate sulfate scale can be avoided and the recovery rate can be improved. Furthermore, it is preferable to use filtered water that is filtered using nanofiltration or ultrafiltration as the supply water, because degradation in efficiency caused by the fouling of the nanofiltration membrane can be alleviated. Regarding the desalination method of the present invention, the first-stage membrane module unit processes 30-100%, preferably 35-95%, and more preferably 40-90% of water, and then mixes the untreated water. The feed water is then supplied to the second-stage membrane module unit. 1229053 V. Description of the invention (6) Furthermore, according to the present invention, the desalination method is preferably performed within the range of 65 to 95% of the permeated water obtained from the first-stage membrane module unit (based on the water supply). The land is 75-90%, and more preferably, the permeate water percentage obtained based on the water supply amount of the second-stage membrane module unit is within the range of 70-85%. In addition, the desalination method is preferably performed in the second stage of the membrane module unit [based on the total amount of feed water (so-called total recovery rate)] of the permeated water amount in the range of 60-80%, preferably 65 -75%. In order to implement the desalination method described above, the desalination device of the present invention includes: at least the first and second membrane module units are located in individual consecutive first and second stages to penetrate with water supply. When the first membrane unit is in the first stage, The microfiltration membrane module unit has a membrane module and a drainage pipe so as to permeate water. When the second membrane unit is in the second stage, the reverse osmosis membrane module unit is arranged in the drainage pipe of the nanofiltration membrane module unit to Water penetration; a transfer device that directs part of the feed water supplied to the nanofiltration membrane module unit to the drainage pipe in order to bypass its membrane module; and (preferably) a device located in the drainage pipe In the second stage, the part of the feed water is mixed with the water penetrated by the nanofiltration membrane module of the reverse osmosis membrane module unit in the first stage. The preferred device according to the present invention includes: a first-stage filter membrane module unit (nano-filtration membrane module unit), preferably the unit has a majority of module components in most individual sub-stages, 1229053 V. Invention Explanation (7) A second-stage filter membrane module unit as a reverse osmosis membrane module unit also has most module components in most individual sub-stages and is arranged in the permeate water pipeline of the nanofiltration membrane module unit A device bypasses part of the feed water supplied to the nanofiltration membrane module unit, and (preferably) a device mixes the bypassed feed water with the permeate water of the nanofiltration membrane module unit, and the mixing device is It is arranged in the supply pipeline of the reverse osmosis membrane module unit. In the above desalination device, it is preferable that the first-stage nanofiltration membrane module unit has most module components in individual sub-stages, and the second-stage nanofiltration membrane module unit is configured in the first stage. Microfiltration membrane module components in the concentrated water pipeline. As explained below, there are at least one module component in each sub-phase, but in any sub-phase (especially the first phase), most of the module components can be parallel to each other. In addition, the relationship between the total membrane surface area S 1 (η) of the nanofiltration membrane module element in each first stage and the total membrane surface area S 1 (η + 1) of the nanofiltration membrane module element in each second stage Preferably within the range of: 1. 5 ^ SI (n) / SI (n + 1) ^ 5 Similarly, the second-stage reverse osmosis membrane module unit preferably has most module elements in individual sub-stages, so the second-stage reverse osmosis membrane module The element is arranged in the concentrated water pipeline of the first-stage reverse osmosis membrane module element. As explained below, there are at least one module component in each sub-phase, but in any sub-phase (especially the first phase), most of the module components can be parallel to each other. In addition, the total number of reverse osmosis membrane module elements in each first stage 1229053 V. Description of the invention (8) Membrane surface area S2 (η) and the total membrane surface area S2 (η + 1) of each second stage reverse osmosis membrane module element The relationship between) is preferably within the range of: 1. 67 ^ S2 (n) / S2 (n + 1) ^ 2. 5 The equipment that can increase the pressure of concentrated water is better placed in the concentrated water pipeline of the reverse osmosis membrane module element upstream of the final reverse osmosis membrane element, or in most reverse osmosis membrane module elements. In addition, the fouling inhibitor injection device is preferably configured in a feed water pipe of a nanofiltration membrane module element unit. Furthermore, the microfiltration membrane module unit or the ultrafiltration membrane module unit is preferably arranged in a supply and feed water pipe of the nanofiltration membrane module element unit. Specific examples of the present invention will be described with reference to the drawings. The specific example of the desalination device of the present invention is described with reference to FIG. 1. In FIG. 1, the desalination device includes a clearing device 2 to remove suspended matter from the seawater of the feed water (flow line 1), nanometers. Membrane module unit 3 and pressure pump 4 'to supply feed water to the nanometer membrane module unit 3, and a loop pipe 5 to bypass the supply of feed water to the part of the nanometer membrane module unit 3, The mixing device 7 mixes the permeated water (flow line 6) from the nanometer membrane module unit with the feed water of the circuit, and a reverse osmosis membrane module unit 9 desalted the supplied water (flow line 8) to obtain the infiltration. Water 11 and a high-pressure pump 10 supply water to the reverse osmosis membrane module unit 9 under pressure. In this specific example, in each of the individual micron filtration and reverse osmosis membrane module units, the module is provided by a single module element. Here, with regard to the first-stage nanofiltration membrane module unit 3, all the supplied feed water is subjected to a nanofiltration process, or part of the feed water is subjected to -10- 1229053 V. Description of the invention (9 ) Nanofiltration process' and the feed water is bypassed by the loop pipe 5 and mixed by the mixing device 7 with the permeate water (flow line 6) of the nanofiltration membrane. At this time, the total salinity of the water supplied to the second-stage reverse osmosis membrane module unit 9 (flow line 8) is adjusted to 55-90% of the feed water, and the calcium ion concentration is adjusted to the same as that of the feed water. % Or less, it is also better to adjust the sulfate ion concentration to 80% or less of the feed water, and its content in seawater is usually 1 500-3500 mg / 1 〇 Control the solute concentration of the supply water 8 The reason is as follows, if the total salinity is within the above range, the osmotic pressure of the supply water 8 of the reverse osmosis membrane module unit 9 in the second stage will decrease, and the operating pressure of the reverse osmosis membrane can be set lower, so the high-pressure pump can be reduced. The power consumption of 10 and the pressure load on the reverse osmosis membrane can also be reduced. The life of the reverse osmosis membrane of the device can be extended, or more permeate water can be obtained with high recovery rate under the same operating pressure. In addition, 'If the calcium ion concentration is higher than the range, the precipitation of calcium sulfate will cause the formation of scale on the surface of the reverse osmosis membrane and suppress the high recovery rate. Therefore, the recovery rate of the osmotic water of the reverse osmosis membrane module unit 9 can be Improve. The form or performance of the nanofiltration membrane is not particularly limited, and any nanofiltration membrane can be used, as long as all the supplied feed water can be subjected to the nanofiltration membrane method, or part of the feed water can be subjected to the nanofiltration membrane method and then The bypassed feed water is mixed, after which the total salinity is 55-90% of the feed water, and the calcium ion concentration is 95% or less of the feed water. However, it is preferable to use nanofiltration membranes made of materials such as polyamidoamine, polyhexamidine, polyesteramido, and crosslinked water-soluble vinyl polymers. In addition, as for the structure of the film, it is preferable to use a film having a fine layer on at least one side of 11-1229053. V. INTRODUCTION (1) A microlayer film having fine holes and gradually moving from the fine layer in the film or toward another layer of the film Enlarge its diameter (ie, asymmetric membrane), or form a very fine separation function layer on the fine layer of the asymmetric membrane with different diameter. Moreover, when a more preferred membrane material is selected, it should be kept in mind that membranes that have the ability to produce large quantities of filtered water under low pressure are preferred. Therefore, the polyamide membrane is particularly excellent in a desired amount of water penetration, that is, chemical resistance, and the polyhexamidine membrane is more excellent. Nanofiltration membranes can be made into spiral roll elements (curling flat membranes on collection tubes), disc-frame elements (stretching elements formed by flat membranes on a double-sided disc-shaped support disc, laminated in the remaining space , And interspersed with gaskets), tubular elements (using tubular membranes) or hole fiber membrane elements (hole fibers are bundled into bundles and packed into cylinders, which are collected in one or more straight lines and as for pressure resistant containers in). Any of the above types of components can be used, but the use of spiral drum components is better in the desired operating performance. The number of components can be arbitrarily set according to the performance of the film. If spiral reel elements are used, the number of elements in a module is preferably set to be 4 to 6 consecutively. Furthermore, regarding the performance of nanofiltration membrane elements, the total salinity at 25 ° C 3. 5% filtered seawater, operating pressure 1. Under the conditions of 5 Mpa and 13% recovery rate, the preferred configuration is: the salt removal rate [TDS (Total Dissolved Salt): evaporation residue] is in the range of 30 to 80%, and the calcium ion removal rate is in the range of 20 to In the 80% range, the removal rate of sulfate ions is 9 5% or higher, and the permeate flow of the film is 0. 3 to 1. In the range of 5 m3 / ni2 / d, the total salinity and calcium ion concentration range of the above-mentioned supply water (flow line 6) can be easily achieved. Better configuration is -12-1229053 5. Description of the invention (11): The removal rate of salt is in the range of 35 to 70%, the removal rate of calcium ions is in the range of 30 to 60%, and the sulfate ion is removed. The rate is 97% or higher. A certain proportion of the feed water for the bypass can be arbitrarily set, as long as the total salinity and calcium ion concentration range meets the above-mentioned supply water (flow line 8), and the amount of bypass is larger on the nanofiltration membrane. Fewer quantities require less energy (electricity) for nanofiltration. On the other hand, if the bypass volume is too large, the total salinity of the nanofiltration membrane must be reduced in order to adjust the total salinity after mixing to the above range, resulting in the need to increase the operating pressure of the nanofiltration membrane or reduce The recovery rate of nanofiltration membrane permeated water is not economical. Therefore, the preferred range for the nanofiltration membrane module components is 30 to 100% of the feed water, and then the untreated feed water of the bypass is mixed, and more preferably 35 to 95%. The best It is 40 to 90%. The mixing device 7 for mixing the nanofiltration membrane permeated water and the bypassed feed water is not particularly limited, and may be, for example, a mixing tank provided in the device, or a device such as a static mixer. According to the recovery rate of the permeated water of the nanofiltration membrane module element 3 in the first stage, if the recovery is low, the total salinity of the permeated water obtained is low, but it is difficult to obtain the estimated water amount, so all the recovery is not increase. Furthermore, if the recovery is too high, the total recovery can be easily improved, but it becomes difficult to reduce the salinity of the nanofiltration membrane permeated water, and the continuous recovery of the second-phase reverse osmosis membrane module element 9 cannot be improved. . Therefore, the proportion of permeated water from the nanofiltration membrane module element 3 (depending on the amount of water supplied) is preferably in the range of 65 to 95%, and more preferably in the range of 70 to 90%. -13- 1229053 V. Description of the invention (12) In addition, in order to economically operate the first-stage nanofiltration membrane module element 3 with the expected recovery rate, it is better to use the configuration shown in the second figure, where more than The microfiltration membrane module element is arranged in the second stage, and the concentrated water is supplied from the nanofiltration membrane module element 3a in the first stage to the nanofiltration membrane module element 3b in the second stage, thereby obtaining permeated water. In the specific example of the second figure, two sets of nanofiltration membrane module elements in this first stage are set up to supply concentrated water to a single nanofiltration membrane module element. At the same time, the total membrane surface area S 1 (η) of the nanofiltration membrane module element 3 a in each first stage and the membrane surface area S1 (n + 1) of the nanofiltration membrane module element 3 b in the second stage The relationship is better within the range of the following formula (1) 1. 5 ^ SI (n) / SI (n + 1) ^ 5 (1) As mentioned above, the membrane area of the first and second stage nanofiltration membrane module elements can be set to increase the membrane surface in the membrane module. The flow rate, so the aging effect of the filtering efficiency due to the concentration polarization phenomenon on the surface of the nanofiltration membrane can be suppressed, so that the total salinity of the permeate water can be kept low and highly recovered. In the range outside the formula (1), the filtering efficiency may be deteriorated because the available surface velocity of the membrane is not sufficient, or if the velocity is too fast, the pressure loss in the module becomes larger, and here There is a danger that the module may be damaged or damaged under such conditions. Regarding the number of secondary stages of the nanofiltration membrane module, the membrane surface flow rate can be set in each stage, especially on a larger number. The filtration ability of the nanofiltration membrane is quickly confirmed, but the extra increase of the number will cause Component sets are too complex and add cost, so they are not economical. From this point of view, the number of secondary stages is actually two to four. -14- 1229053 V. Description of the invention (13) In any sub-unit, most of the nanofiltration membrane module elements can be set in parallel, and water is supplied between them. As explained earlier, in the second figure, there are two such module elements in the first stage, and the concentrated water from each of them is introduced into a single module element in the second stage. In all stages, the number of module elements, from the module elements in the previous stage, penetrates better and bypasses all downstream continuous module elements, and the module elements in the last stage are introduced into the percolation flow line. The pressure pump 4 for supplying the nanofiltration membrane module unit 3 is not particularly limited. Different types of pumps can be used, such as centrifugal pump, scroll pump, scroll pump and plunger pump. Subsequently, in the second reverse osmosis membrane module unit 9, the supply water (flow line 8) from the first-stage nanofiltration membrane module unit 3 is pressurized by a pressure pump 10 to a preset pressure equal to or greater than The osmotic pressure is desalinated by a reverse osmosis membrane module unit and separated into osmotic water (flow line 1 1) and concentrated wastewater (flow line 1 3). Any reverse osmosis membrane is acceptable, as long as the water is selectively permeable and total salt penetration can be avoided. As for the structure of the membrane, it is better to use an asymmetric membrane, a membrane having a fine layer on at least one side, which gradually expands its diameter from the fine layer in the membrane toward the other layer of the membrane, or asymmetric materials with different diameters in different substances. A very fine separation function layer is formed on the fine layer of the membrane. Materials used as membranes include cellulose acetate polymers, polyamides, polyesters, polyamides, vinyl polymers, and other similar polymeric materials. The preferred typical reverse osmosis membranes include acetate fibers Element or Polyamide with -15-1229053 V. Description of the Invention (14) Asymmetric membrane and compound film with active layer of polyamine or polyurea, compound film with active layer of aromatic polyamine. Among them, the compound film of aromatic polyamine is particularly preferable, because its stable performance is obvious even when the characteristics of water are changed, and harmful substances such as trihalomethane and similar environmental hormones can be appropriately removed. When a nanofiltration membrane is used, a reverse osmosis membrane type is preferably used from the viewpoint of operability, which can use a spiral reel element, a disc-frame element, a tubular element, or a hole fiber membrane element, and even if any Type, but spiral coil elements are preferred. According to the performance of the membrane, the number of components can be arbitrarily set, and if a spiral reel component is used, the number of components provided to a single module in a pressure vessel is preferably set continuously about 4 to 6. In addition, regarding the effectiveness of reverse osmosis membrane elements, the total salinity at 25 ° C 3. 5% filtered seawater, operating pressure 1. Under the conditions of 5 Mpa and a recovery rate of 13%, the preferred configuration is the salt removal rate [TDS (Total Dissolved Solids): evaporation residue concentration] of 99% or more, and the permeate flow of the film is 0.3 to 1 . In the range of 5m3 / m2 / d, the quality of the permeated water is excellent and the permeated water can be obtained efficiently. Regarding the reverse osmosis membrane module unit 9, the permeate water recovery rate is 'higher for comprehensive recovery (this is what we are pursuing)', but if it is too high, the necessary operating pressure becomes high and the permeate water quality obtained Also worse 'so it is not economical. In addition, setting a low recovery rate improves the quality of the permeate water obtained ', but the amount obtained is small and the total recovery is reduced', so it is not economical. Therefore, the ratio of the amount of permeated water from the reverse osmosis membrane module unit (to the amount of water supplied) is better than -16-1229053 V. Description of the invention (彳 5) is preferably 70 to 85%. In addition, in order to efficiently operate the reverse osmosis membrane module unit 9 with the expected recovery rate, it is preferable to use the configuration shown in the second figure ', in which most of the reverse osmosis membrane module elements are arranged in the secondary stage. The primary stage reverse osmosis membrane module element 9a supplies concentrated water to the second stage reverse osmosis membrane module element 9b, thereby obtaining permeated water. In the specific example of the second figure, two sets of this first-stage reverse osmosis membrane module element are set and supplied with concentrated water to a single second-stage reverse osmosis membrane module element. At the same time, the relationship between the total membrane surface area S2 (η) of the reverse osmosis membrane module element 9a in the first stage and the membrane surface area S2 (n + 1) of the reverse osmosis membrane module element 9b in the second stage is better. Within the range of the following formula (2) 1. 67 ^ S2 (n) / S2 (n + 1) ^ 2. 5 (2) As mentioned above, the membrane area of the first and second stage reverse osmosis membrane module components can increase the membrane surface flow rate in the membrane module, so it is caused by the concentration polarization on the surface of the reverse osmosis membrane. The aging of the filtration efficiency of the phenomenon can be suppressed, thereby maintaining high permeate water quality even with high recovery, and the decrease in the amount of permeate water due to the reduction in effective pressure due to concentration polarization can be suppressed. In the range outside the formula (2), the filtered water quality or the amount of water produced can be reduced because the available membrane surface velocity is not sufficient, or if the velocity is too fast, the pressure loss in the module becomes It is too large, and there is a danger that the module may be damaged or damaged in this condition. Regarding the number of reverse osmosis membrane modules in the next stage, the membrane surface flow rate can be set in each stage, especially in a larger number. The filtration capacity of the reverse osmosis membrane is -17-1229053 V. Description of the invention (16) It is confirmed, but the excessive increase of the number of chaos will make the component set too complicated and increase the cost, so it is not economical. From this perspective, the number of secondary stages is actually two to four. In any subunit, most of the reverse osmosis membrane module elements can be set in parallel and water is supplied between them separately. For example, in the second figure, there are two such module elements in the first stage, and the concentrated water from each of them is introduced into a single module element in the second stage. In all stages, the penetration of all the number of module elements is better than that of the module elements in the previous stage, bypassing all downstream continuous module elements, and the module elements in the last stage are introduced into the infiltration flow line. Regarding the operating pressure of the reverse osmosis membrane module element at each stage, by operating the second stage reverse osmosis membrane module element only with the pressure of water supplied from the first stage reverse osmosis membrane module element, the permeate water can be Obtained under a sufficiently efficient method, and no separate pressurization device is provided, but as shown in FIG. 3, in the first stage of the reverse osmosis module unit, the reverse osmosis membrane module element 9a and the second stage In the concentrated water pipe 15 between the osmotic membrane module elements 9b, the pressure of the concentrated water is pressurized by a pressure increasing device 16 to increase the operating pressure so as to supply concentrated water to the second stage reverse osmosis membrane module elements. It is preferable to obtain permeated water. Because the separation efficiency of the reverse osmosis membrane module components in each stage is further improved, permeate water can be efficiently obtained. At the same time, between the operating pressure in each stage, the operating pressure P (η) of the reverse osmosis membrane module element in the first stage and the operating pressure P (η + 1) of the reverse osmosis membrane module element in the second stage The relationship is better within the range of -18-1229053 V. Description of the invention (η) 1. 15 ^ P (n + l) / P (n) ^ 1. 8 In addition, if the total salinity of the seawater is 3. 5% as an example, with 40% recovery of reverse osmosis membrane module 5. 5 to 7. 〇 MPa operating pressure is necessary, and at 60% is 8.5 to 10. 〇 MPa. However, in the present invention, the total salinity of the seawater supplied to the reverse osmosis membrane module has been reduced to 2 through the nanofiltration membrane. 0 to 3. 1%, so the operating pressure can be set lower than normal with the same recovery. The special operating pressure is appropriately selected according to the concentration of the feed water, the adjustment of the total salinity in the module unit 3 of the nanofiltration membrane, and the reverse osmosis membrane module unit 9; however, 'for example, if the total salinity is 3. 5% of seawater is adjusted with nanofiltration membrane module unit 3 to have a total salinity of 2. 5% of seawater is supplied to the reverse osmosis membrane module unit 9 as 80% recovery, then the operating pressure is set to 8. 0 to 9. Within 5 MPa. The high-pressure pump 10 of the reverse osmosis membrane module unit 9 can use various types of pumps, such as a centrifugal pump, a scroll pump, a turbo pump, and a plunger pump. Furthermore, regarding the booster device 16, if a majority of the reverse osmosis membrane module sub-stages are provided, and the reverse osmosis water pressure from the first stage reverse osmosis membrane module elements is pressurized, such as a centrifugal pump or a vortex can be used Volume pump pressure pump. In addition, as described above, the operating pressure of the reverse osmosis membrane module unit 9 is extremely high (about 8 · 0 to 9 · 5 MPa), and the concentrated water discharged from the unit also has about the same pressure. Therefore, as shown in the second and third figures, the energy recovery device 14 is preferably arranged to recover the pressure energy of the permeated water. Any method can be used as long as it can achieve energy recovery, such as reflux pump, Pelton turbine (-19-1229053 V. Invention Description (18) Pelton turbine), turbine charger and pressure converter, etc. The method is a configuration as shown in FIG. 4, in which an energy recovery device 14 is provided in the first stage of most reverse osmosis membrane module stages to boost the pressure of concentrated water. In this case, the turbine charger is used as an energy recovery device (disclosed in, for example, JPA0 1 294903), which is preferred because of the device's external shape and easy operation. The better and better operation of the device is to express the final amount of permeate water obtained through the reverse osmosis membrane module unit 9 as a percentage of the amount of feed water, in the range of 60 to 80%, and more preferably 65 to 75%. . At present, in the osmotic water of nanofiltration membranes and reverse osmosis membranes, the concentration of increased salinity occurs simultaneously by increasing the concentrations of calcium ions and sulfate ions (which are scale components). At this time, if the concentrations of both ions increase, Such as calcium sulfate scale will be deposited on the membrane surface. My experiments have confirmed that the minimum ion concentration that causes calcium sulfate scale precipitation is about 1 200 mg / 1 calcium ion and about 2900 mg / I sulfate ion, and as long as the concentration of the two ions does not exceed the above, there will not be 15 sulfuric acid products. The risk of scale deposits on the membrane surface. According to the present invention, the operating conditions of the nanofiltration membrane module unit and the mixing ratio with the feed water of the bypass can be adjusted, and the operating conditions of the recovered reverse osmosis membrane module unit can be set to the precipitation of calcium sulfate scale It does not occur on the surface of the reverse osmosis membrane, so there will not be any problems regarding the deposition of scale on the reverse osmosis membrane module. On the other hand, in terms of the nanofiltration membrane module, as described above, there is a large -20-1229053 in the percentage of calcium ion removal according to the performance of the nanofiltration membrane used. 5. Description of the invention (19) Difference, so When using a nanofiltration membrane with a relatively low percentage of calcium ion removal, scale deposition on the surface of the nanofiltration membrane is not easy to occur, because the concentration of calcium ion in the nanofiltration membrane does not easily increase. Even if at high recovery rates. However, if a nanofiltration membrane with a high percentage of calcium ion removal is used, there is a danger that the concentration of calcium ions will increase in the concentrated water on the surface of the nanofiltration membrane and calcium sulfate scale precipitation will occur. Therefore, when using this calcium ion to remove a nanometer membrane with a high percentage, the nanofiltration membrane module unit preferably adds a fouling deposition inhibitor to the supply water, and then operates the device. Regarding the position where the scale precipitation inhibitor is injected, in comparison with the scale precipitation inhibitor directly injected into the feed water so that the scale precipitation inhibitor is also introduced to the circuit side, if the nanofiltration membrane mold after the split circuit is connected, The group unit (reference number 17 shown in Fig. 1) is injected directly before, so less scale precipitation inhibitor needs to be added, so the configuration is better. Regarding the type of scale precipitation inhibitor, any type can be used as long as calcium sulfate scale precipitation can be prevented. However, from the viewpoint of price and the desired effect, polyphosphates such as sodium hexametaphosphate (SHMP), organic monomers such as ethylenediaminetetraacetic acid (EDTA), such as polyacrylic acid or polymer, are preferably used. Organic polymer of alginic acid. Regarding the method for injecting the fouling precipitation inhibitor, there is no particular limitation on the method. 'As long as the supply water is metered in, the diaphragm pump or gear pump is used to inject the pressure pump into the suction part for the nanofiltration membrane module. It is preferable because the injection can be performed accurately and efficiently. Furthermore, although the present invention can be supplied with various forms of water, such as river water, lake-21-1229053 V. Description of the invention (20) and marsh water, groundwater and industrial wastewater ', it is better to process seawater or high-concentration saline water. Because it can be displayed in characteristics such as high recovery and economic efficiency. The sludge density index (SDI 値) is an index representing impurities in the feed water, and is preferably controlled below 4. For water with an SDI of less than 4, there is almost no fouling of suspended matter adsorbed on the nanofiltration membrane or reverse osmosis membrane, so the device can be operated in a stable manner for a long time. It must be noted that SDI 値 represents the concentration of suspended matter in the water and is expressed by (1-T0 / T15) X 100/15, where T. Means when 0. 0 at 2 MPa filtration pressure When the 45 / zm microfiltration membrane is performed, the time required to filter the 500 ml sample water before the filtration, and T15 means the time required to filter the other 500 ml sample water after the subsequent filtration 15 under the same conditions, without suspended matter The total yield of water is 0, and the maximum water content of most impurities is 6. 67. The purification device 2 for controlling the feed water SDI 値 lower than 4 is not particularly limited by its method, but it is preferable to use a condensation sedimentation or freezing sand filtration method, a polishing filtration method, or other filtration methods as generally used. Furthermore, it is better to use a microfiltration membrane module or an ultrafiltration membrane module for filtration, because the pollution of the nanofiltration membrane module and the reverse osmosis membrane module due to suspended matter, microorganisms and the like can be reduced and stable operation can be performed. And the life of membrane elements can be extended. The microfiltration membrane has a range of 0. 1 to 1 // m fine-pore separation membrane for permeating water and dissolved components but removing suspended matter, fine particles and microorganisms, 0. 1 // m or greater. Ultrafiltration membranes have a range of 0. 01 to 0. 1 # m fine pore separation membrane, used to penetrate water and dissolve components but remove organic polymers, fine particles, and disease-22-1229053 V. Description of the invention (21) Toxins and microorganisms, 0 · 1 // m or The bigger one. With regard to the present invention, the microfiltration membrane and the ultrafiltration membrane may be composed of any substance and may be in any form as long as the membrane has the above functions or fine pores. In other cases, examples of materials that can be used as the membrane include organic polymer membranes such as polyacrylonitrile, polymill, polyethylene, polypropylene, polyether mill, and cellulose acetate polyimide; and ceramic filter membranes, such as Alumina, chromium oxide and alumina-silica. It can be in the form of a tubular membrane, such as hollow fiber, tubular or monolithic, or a flat membrane, such as spiral or flat-frame. In addition, according to the above configuration using a filtering method, if deep seawater with a depth of 200 m or more is used, or sand obtained from the sea floor is used as a filter, the filtering process is not required, and this configuration is also preferable. Preferred embodiments of the present invention will now be described in more detail with reference to the following examples and comparative examples. '' Examples 1-10 and Comparative Examples 1-5 The efficacy of the nanofiltration membrane was evaluated by the recovery rate and the operating pressure. As shown in Figure 1, the desalination device with a two-stage membrane module that is continuously assembled is composed of a nanofiltration membrane module and a reverse osmosis membrane module. As far as the nanofiltration module is concerned, the assembly diameter is 4 inches with 7. A component of 0 m2 membrane area, and 4 to 6 of this component are placed in a pressure tank for use as a membrane module. The total desalting force of the nanofiltration membrane module used is about 62%, and the percentage of calcium ion removal is about 53. %, Sulfate ion removal percentage is about 97%, and pH 6. 5.Total salinity is about 3. 25t seawater at 5%, calcium ion concentration of about 350 mg / I, and sulfate ion concentration of about 2100 mg / 1 at operating pressure 1. Under the filtration conditions of 5 MPa and 13% recovery, about 4. 9 m3 / d of water. In addition, in terms of reverse osmosis -23-1229053 V. Description of the invention (22) Permeable membrane module, the same method of assembling a nanofiltration membrane with a diameter of 4 inches has 7. 0 m2 membrane area of the element, and 6 to 8 of this element are placed in the pressure tank for the membrane module, the total desalination force of the reverse osmosis membrane module used is about 99. 7%, and total salinity is about 3. 5%, pH 6. 5 at 25 ° C seawater at operating pressure 5. Under filtration conditions of 5 MPa and 13% recovery, about 5. 0 m3 / d of water. Use the microfiltration membrane element to adjust the SDI 値 of seawater to 2. 5 to 3. 5 range and supplied to this desalination device, and the seawater has a total salinity of about 3. 5%, calcium ion concentration of about 350 mg / I, and sulfate ion concentration of about 2100 mg / I. The seawater is processed by the nanofiltration membrane module unit, using filtered water or seawater mixed with the bypass, and under the operating conditions shown in Example 1-10 of Table 1, the water supplied to the reverse osmosis membrane module unit is according to Table 1 The salinity and calcium ion concentration shown are prepared and supplied to a reverse osmosis membrane module. On the other hand, as for the comparative example, a desalination apparatus which is completely the same as the example was used outside the operating conditions of the present invention, as shown in Table 1 Comparative Examples 1 and 5, and the performance was measured after 24 hours of operation. According to the results, when the steps of the example allow the reverse osmosis membrane module to operate at a relatively low operating pressure and a high recovery, high-quality fresh water is obtained. These comparative examples have inadequate recovery due to the formation of scale, require higher operating pressure to obtain fresh water under the same recovery as the example, or under the same reverse osmosis membrane operating pressure as the example, In comparison, only a lower recovery operation can be allowed. In addition, the concentration of calcium ions in nanofiltration membranes and reverse osmosis membranes is analyzed by ICP emission spectrometry specified in IS K01 01, and the sulfate ion concentration is analyzed by ion chromatography analysis also specified in HS K0101. real
-24- 1229053 五、發明說明（23) 例1-10及比較例1-3之分析，濃度低於硫酸鈣積垢沉積 極限，且事實上確定在濃縮水中並無積垢之沉澱。但進行 不具毫微過濾製程之配置及逆滲透製程以高回收進行（第 5比較例），則逆滲透膜模組之鈣離子濃度及硫酸離子濃 度同時達到或超過積垢沉積極限，且事實上確定在濃縮水 中有積垢之沉澱。 實例1 1 - 1 3 在使用具高鈣移除之毫微濾膜估計積垢抑制劑之功效。 使用與實例1相同之裝置，除了所使用之毫微濾膜模組具 有總脫鹽力約65%，高的鈣離子移除百分率約72%，硫酸 離子移除百分率約99%，.且產生約4.8 m3/d之水，且在具 有pH 6.5、總鹽度約3.5%、鈣離子濃度約3 50 mg/I、及 硫酸離子濃度約2100 mg/I之25°C海水於操作壓力1.5 MPa及13%回收之過濾條件下。以表1中之實例顯示，以 在實例1 1 - 1 3所表示之比率添加作爲積垢抑制劑之六偏磷 酸鈉至供應進料水中以供毫微濾膜模組，且在表1之條件 下進行脫鹽。根據結果，以實例11 - 1 3而言，因爲積垢抑 制劑，濃縮水的鈣離子濃高但無積垢發生在毫微濾膜模組 上。所以，當逆滲透膜模組亦在高回收下操作時，毫微濾 膜模組可以高回收進型而步生成積垢。 實例1 4 毫微濾膜模組單元及逆滲透膜模組單元中個別多階段配 置功效之估計。使用8個與實例1相同之毫微濾膜模組元 -25- 1229053 五、發明說明（24) 件，具三個元件之二個設定被置於個別的壓力槽中，以形 成個別的毫微濾膜模組，其使用作爲第一次階段模組元件 ，具二個元件之一個設定被置於一個壓力槽中，以形成一 個毫微濾膜模組，其使用作爲單一第二階段模組元件’藉 以組成毫微濾膜模組單元；及使用1 2個與實例1相同之 逆滲透膜模組單元，具四個元件之三個設定被置於個別的 壓力槽中，以形成個別的逆滲透膜模組，其中二個使用作 爲個別的第一次階段模組元件，而一個使用作爲第二次階 段模組元件，藉以組成逆滲透膜模組單元。因而組成之脫 鹽裝置顯示於第2圖。 以冷凝砂濾裝置調整海水之SDI値爲3至4範圍內而供 應至此脫鹽裝置，而海水具有總鹽度約3.5%、鈣離子濃度 約 3 50 mg/I、及硫酸離子濃度約 2100 mg/I。其中， 70m3/d其70%被供至毫微濾膜模組單元，在25 °C調整毫微 過濾製程之操作壓力爲2. 5 MPa，然後毫微濾膜模組單元 產生具有2.0 7%總鹽度、鈣離子濃度2 39 mg/I、及硫酸離 子濃度133 mg/I之滲透水57.7 m3/d，回收率82.4%。其 次，由毫微濾膜模組單元獲得之滲透水在靜態混合器中混 合3 0%之進料水，產生具有2. 56%總鹽度、.鈣離子濃度 276mg/I、及硫酸離子濃度 805 mg/I之滲透水體積 57.7m3/d 。 之後，將所調整之海水供應至供至逆滲透膜模組單元， 將逆滲透分離進行於9.0 MPa之操作壓力，藉以在80%回 -26- 1229053 五、發明說明（25) 收率下產生70 m3/d之產物水，其淡水水質具有2 26 mg/1 之總鹽度。同時，由供應至脫鹽裝置的100 m3/d進料水 的逆滲透膜模組滲透水之總回收爲70%。 再者，在上述操作條件下連續操作進行約三個月，且來 自逆滲透膜模組單元之淡水流、水質、回收、操作壓力等 幾乎與剛開始操作時相同，亦即沒有發生效能老化。 實例15 以增加第一階段濃縮物之壓力以估計逆滲透膜模組單元 中多階段配置之功效。以實例1 4相同之方法配置脫鹽裝 置，除了將離心增壓泵浦設置於第一階段逆滲透膜模組之 濃縮水管道中，因而組成之脫鹽裝置顯示於第3圖。 以超濾膜裝置調整海水之SDI値低於1 . 5而供應至此脫 鹽裝置，而海水具有總鹽度約 3 . 5%、鈣離子濃度約 3 5 0mg/I、及硫酸離子濃度約2100 mg/I。在與實例14相 同條件下進行超濾製程，並混合繞道之進料水，藉以製備 與實例1 4相同成分及用量之進料水以供應至逆滲透膜模 組單元。 之後將所有調整後之海水供應至逆滲透膜模組單元，將 逆滲透分離進行於6.5 MPa之操作壓力以供逆滲透膜模組 元件。且以9.0 MPa之操作壓力供於第二階段逆滲透膜模 組元件，藉以在75%之回收率下產生66 m3/d之產物水， 其淡水水質具有174 mg/I之總鹽度。同時，來自供應至 脫鹽裝置的100 m3/d進料水的逆滲透膜模組滲透水之總 -27- 1229053 五、發明說明（26) 回收爲6 6 %。 再者，在上述操作條件下連續操作進行約三個月，且來 自逆滲透膜模組單元之淡水流、水質、回收、操作壓力等 幾乎與剛開始操作時相同，亦即沒有發生效能老化。 發明功效 根據本發明，可抑制因懸浮物質及鈣積垢所導致之逆滲 透膜污損，逆滲透膜因降低總鹽度而可在高回收率下操作 ’例如以高回收低成本在穩定的方法下將海水製成淡水。 -28- 1229053 五、發明說明（27) _ 表1 實 例 進料水 繞道 毫微濾膜模組單元 (m3/d) 比例 供應水 元 滲透水(24小時後） 濃縮水(24小時後） 編 (%) 流 壓力 積垢 件 流 回收率 鹽度 Ca2+ Ca2+ S02+ 積垢 號 (m3/d) (MPa) 抑制劑 號 (m3/d) (%) (mg/1) (mg/1) (mg/1) (mg/1) (形成) (ml/1) 1 40 0 40.0 2.5 - 6 35.4 88.6 22393 254 1092 17190 無 2 40 0 40.0 2.5 — 6 35.4 88.6 22393 254 1092 17190 Μ yiw 3 40 10 36.0 2.0 - 6 29.8 82.8 20741 239 884 11565 yfrrr 4 40 10 36.0 2.0 - 6 29.8 82.8 20741 239 884 11565 int 5 45 20 36.0 2.5 - 5 30.6 85.1 21397 245 850 13300 •fnT 無 實 6 50 30 35.0 2.5 — 5 30.3 86.5 21796 249 998 14610 無 7 55 40 33.0 2.0 - 5 25.8 78.1 19786 230 779 9161 無 例 8 70 45 35.0 2.5 一 5 30.3 86.5 21796 249 998 14610 4τττ Ws 9 75 60 30.0 2.5 一 4 25.0 83.5 21067 242 897 12023 無 10 100 70 30.0 2.5 — 4 25.0 83.5 21067 242 897 12023 >fnT 11 40 0 40.0 2.5 1.0 6 34.7 86.8 20534 176 1492 15660 無 12 50 30 35.0 2.0 0.5 6 28.9 82.5 19383 165 1222 11843 4rrr. 撕 13 100 70 30.0 2.5 1.5 5 27.4 91.4 22340 195 2001 23937 Μ ✓ ι、、 1 150 80 30.0 2.5 - 4 25.0 83.5 21067 242 897 12023 4τττ 撕 比 2 150 80 30.0 2.5 — 4 25.0 83.5 21067 242 897 12023 Μ 較 3 150 85 22.5 2.0 — 4 19.5 86.7 21974 250 998 14772 视 例 4 40 100 5 40 100 — 進料水 鹽度濃度：34987 mg/l，Ca2+濃度：350 mg/l，SO,濃度：2100 mg/1，溫度：25°C，pH : 6.5 毫微濾膜元件功效 脫鹽率：62%，Ca2+移除百分比：53%，S042_移除百分比：97%， 淡水生成量：4.9 m3/d[在上述進料水條件下估計及1.5 MPa之壓力] -29- 1229053 五、發明說明（28) 表1 (續） 送滲透膜模組單元 總回 供應水(毫微過濾+繞道之水） 元 滲透水(24小時後） 濃縮水(24小時後） 流 鹽度 Ca+ 壓力 件 流 回收 鹽度 Ca2+ S042- 積垢 收率 (m3/d) (mg/1) (mg/1) (MPa) 號 (m3/d) (%) (mg/1) (mg/1) (mg/1) (形成) (%) 35.4 22393 254 8.5 6 28.0 79.0 269 1191 731 無 70.0 35.4 22393 254 9.2 6 29.5 83.3 301 1492 903 dnt Μ 73.8 33.8 22428 252 8.4 6 26.7 79.0 283 1184 1732 irrC m 66.8 33.8 22428 252 9.2 6 27.8 82.2 312 1400 2030 -far 無 69.5 39.6 24485 269 8.7 6 30.5 77.0 250 1160 2547 dot 67.8 45.3 26171 282 9.0 6 34.4 75.9 234 1176 3306 ^\\\ 69.0 47.8 26789 285 8.7 8 36.3 75.9 289 1188 4303 r. 11M 66.0 32.7 28876 303 9.0 6 24.5 74.9 361 1190 4765 4at 70.0 35.0 30018 311 9.0 6 25.9 74.0 343 1197 5378 fnr ρΤΤΓ j\\\ 69.1 47.5 31329 322 9.0 8 34.7 73.1 329 1185 5852 M /\s\ 69.4 34.7 20534 176 9.0 6 28.5 82.1 290 980 221 dnt Ws 71.3 43.9 24722 228 9.0 8 34.9 79.5 333 1142 3708 flTf 69.8 48.7 31436 306 9.2 8 35.6 73.1 323 1178 5854 4at 71.2 48.3 32594 331 10.1 6 34.8 72.0 272 1183 6290 4τττ Μ 69.6 48.3 32594 331 9.0 6 31.9 66.0 234 973 5172 dnL Μ 63.8 49.0 33272 337 9.0 6 31.3 63.9 233 936 5110 4πτ Μ 62.7 40.0 34990 350 9.0 6 24.5 61.3 307 901 5414 Μ 61.3 40.0 34990 350 11.5 6 27.6 69.0 307 1241 7442 ίΒΕΕ "、、 69.0 逆滲透膜元件功效 脫鹽率：99.7%，淡水生成量：5.0 m3/d， [在上述進料水條件下估計及5.5 MPa之壓力] 積垢抑制劑 六偏磷酸鈉 -30--24- 1229053 V. Explanation of the invention (23) The analysis of Examples 1-10 and Comparative Examples 1-3 showed that the concentration was lower than the calcium sulfate deposition limit, and in fact, it was determined that there was no scale precipitation in concentrated water. However, when the configuration without the nanofiltration process and the reverse osmosis process are performed with high recovery (Comparative Example 5), the calcium ion concentration and sulfate ion concentration of the reverse osmosis membrane module simultaneously reach or exceed the scale deposition limit, and in fact Make sure there is scale deposits in the concentrated water. Examples 1-1 3 The efficacy of a fouling inhibitor was estimated using a nanofiltration membrane with high calcium removal. Using the same device as in Example 1, except that the nanofiltration membrane module used has a total desalting power of about 65%, a high calcium ion removal percentage of about 72%, a sulfuric acid ion removal percentage of about 99%, and produces about 4.8 m3 / d of water at 25 ° C with pH 6.5, total salinity of about 3.5%, calcium ion concentration of about 3 50 mg / I, and sulfate ion concentration of about 2100 mg / I at an operating pressure of 1.5 MPa and 13% recovery under filtration conditions. The example shown in Table 1 shows that sodium hexametaphosphate as a fouling inhibitor is added to the feed water for the nanofiltration membrane module at the ratios shown in Examples 1 1 to 13 and shown in Table 1 Desalting is performed under conditions. According to the results, in the case of Examples 11-13, the calcium ion concentration of the concentrated water was high due to the scale inhibitor, but no scale occurred on the nanofiltration membrane module. Therefore, when the reverse osmosis membrane module is also operated under high recovery, the nanofiltration membrane module can be highly recovered into the mold and generate scale. Example 14 Estimates of the efficacy of individual multi-stage configuration in 4 nanofiltration membrane module units and reverse osmosis membrane module units. Using eight nanofiltration membrane module elements which are the same as in Example 1-25-1229053 V. Description of the invention (24) pieces, two settings with three components are placed in separate pressure tanks to form individual milliseconds Microfiltration membrane module, which is used as a first-stage module component, and one setting with two components is placed in a pressure tank to form a nanofiltration membrane module, which is used as a single second-stage module Group of elements' is used to form a nanofiltration membrane module unit; and 12 reverse osmosis membrane module units which are the same as in Example 1 are used. Three settings with four components are placed in individual pressure tanks to form individual units. Of the reverse osmosis membrane module, two of which are used as individual first-stage module elements, and one is used as the second-stage module element to form a reverse osmosis membrane module unit. The composition of the desalination apparatus is shown in FIG. 2. The condensed sand filter device was used to adjust the SDI 値 of seawater to a range of 3 to 4 and supplied to this desalination device. The seawater has a total salinity of about 3.5%, a calcium ion concentration of about 3 50 mg / I, and a sulfate ion concentration of about 2100 mg / I. Among them, 70% of 70m3 / d is supplied to the nanofiltration membrane module unit, and the operating pressure of the nanofiltration process is adjusted to 2.5 MPa at 25 ° C, and then the nanofiltration membrane module unit generates 2.0 7% Total salinity, calcium ion concentration of 2 39 mg / I, and sulfate ion concentration of 133 mg / I permeate water 57.7 m3 / d, with a recovery rate of 82.4%. Second, the permeate water obtained from the nanofiltration membrane module unit was mixed with 30% of the feed water in a static mixer to produce a total salinity of 2.56%, a calcium ion concentration of 276mg / I, and a sulfate ion concentration. The osmotic water volume of 805 mg / I was 57.7 m3 / d. After that, the adjusted seawater is supplied to the reverse osmosis membrane module unit, and the reverse osmosis separation is performed at an operating pressure of 9.0 MPa, so that 80% is returned to -26-1229053 V. Description of the invention (25) The yield is generated The product water of 70 m3 / d has fresh water with a total salinity of 2 26 mg / 1. At the same time, the total recovery of permeate water from the 100 m3 / d feed water supplied to the desalination unit was 70%. Furthermore, continuous operation was performed for about three months under the above-mentioned operating conditions, and the fresh water flow, water quality, recovery, operating pressure, etc. from the reverse osmosis membrane module unit were almost the same as when the operation was just started, that is, no performance aging occurred. Example 15 The pressure of the first-stage concentrate was increased to estimate the efficacy of a multi-stage configuration in a reverse osmosis membrane module unit. The desalination device was configured in the same manner as in Example 14, except that the centrifugal booster pump was set in the concentrated water pipeline of the first-stage reverse osmosis membrane module, and the composition of the desalination device is shown in FIG. 3. The ultrafiltration membrane device was used to adjust the SDI of the seawater to less than 1.5 and supplied to the desalination device. The seawater had a total salinity of about 3.5%, a calcium ion concentration of about 350 mg / I, and a sulfate ion concentration of about 2100 mg. / I. The ultrafiltration process was performed under the same conditions as in Example 14 and the bypass feed water was mixed to prepare feed water with the same composition and amount as in Example 14 to supply to the reverse osmosis membrane module unit. After that, all the adjusted seawater is supplied to the reverse osmosis membrane module unit, and the reverse osmosis separation is performed at an operating pressure of 6.5 MPa for the reverse osmosis membrane module element. It was supplied to the second-stage reverse osmosis membrane module components at an operating pressure of 9.0 MPa, so as to produce 66 m3 / d of product water at a 75% recovery rate. The fresh water quality had a total salinity of 174 mg / I. At the same time, the total permeated water of the reverse osmosis membrane module from the 100 m3 / d feed water supplied to the desalination unit was -27-1229053. V. Description of the invention (26) The recovery was 66%. Furthermore, continuous operation was performed for about three months under the above-mentioned operating conditions, and the fresh water flow, water quality, recovery, operating pressure, etc. from the reverse osmosis membrane module unit were almost the same as when the operation was just started, that is, no performance aging occurred. EFFECTS OF THE INVENTION According to the present invention, fouling of reverse osmosis membranes caused by suspended matter and calcium scale can be suppressed, and reverse osmosis membranes can be operated at high recovery rates by reducing the total salinity ', such as high recovery and low cost in stable Under the method, seawater is made into fresh water. -28- 1229053 V. Description of the invention (27) _ Table 1 Example Feed water bypass nanofiltration membrane module unit (m3 / d) Proportional supply of water permeate water (after 24 hours) Concentrated water (after 24 hours) (%) Flow pressure fouling flow recovery salinity Ca2 + Ca2 + S02 + Scale number (m3 / d) (MPa) Inhibitor number (m3 / d) (%) (mg / 1) (mg / 1) (mg / 1) (mg / 1) (formation) (ml / 1) 1 40 0 40.0 2.5-6 35.4 88.6 22393 254 1092 17190 None 2 40 0 40.0 2.5 — 6 35.4 88.6 22393 254 1092 17190 Μ yiw 3 40 10 36.0 2.0 -6 29.8 82.8 20741 239 884 11565 yfrrr 4 40 10 36.0 2.0-6 29.8 82.8 20741 239 884 11565 int 5 45 20 36.0 2.5-5 30.6 85.1 21397 245 850 13300 • fnT No real 6 50 30 35.0 2.5 — 5 30.3 86.5 21796 249 998 14610 none 7 55 40 33.0 2.0-5 25.8 78.1 19786 230 779 9161 no case 8 70 45 35.0 2.5 one 5 30.3 86.5 21796 249 998 14610 4 τττ Ws 9 75 60 30.0 2.5 one 4 25.0 83.5 21067 242 897 12023 no 10 100 70 30.0 2.5 — 4 25.0 83.5 21067 242 897 12023 > fnT 11 40 0 40.0 2.5 1.0 6 34.7 86.8 205 34 176 1492 15660 None 12 50 30 35.0 2.0 0.5 6 28.9 82.5 19383 165 1222 11843 4rrr. Tear 13 100 70 30.0 2.5 1.5 5 27.4 91.4 22340 195 2001 23937 Μ ✓, 1 150 80 30.0 2.5-4 25.0 83.5 21067 242 897 12023 4 τττ Tear ratio 2 150 80 30.0 2.5 — 4 25.0 83.5 21067 242 897 12023 Μ compared to 3 150 85 22.5 2.0 — 4 19.5 86.7 21974 250 998 14772 Visual example 4 40 100 5 40 100 — Salinity concentration of feed water: 34987 mg / l, Ca2 + concentration: 350 mg / l, SO, concentration: 2100 mg / 1, temperature: 25 ° C, pH: 6.5 The efficiency of the nanofiltration membrane element desalination rate: 62%, Ca2 + removal percentage: 53%, S042_Removal percentage: 97%, fresh water production: 4.9 m3 / d [estimated under the above feed water conditions and a pressure of 1.5 MPa] -29-1229053 V. Description of the invention (28) Table 1 (continued) Send infiltration Membrane module unit total supply water (nanofiltration + bypass water) Element permeate water (after 24 hours) Concentrated water (after 24 hours) Salinity Ca + Pressure salvage salinity Ca2 + S042- Fouling yield ( m3 / d) (mg / 1) (mg / 1) (MPa) (m3 / d) (%) (mg / 1) (mg / 1) (mg / 1) (Formation) (%) 35.4 22393 254 8.5 6 28.0 79.0 269 1191 731 None 70.0 35.4 22393 254 9.2 6 29.5 83.3 301 1492 903 dnt Μ 73.8 33.8 22428 252 8.4 6 26.7 79.0 283 1184 1732 irrC m 66.8 33.8 22428 252 9.2 9.2 6 27.8 82.2 312 1400 2030 -far None 69.5 39.6 24485 269 8.7 6 30.5 77.0 250 1160 2547 dot 67.8 45.3 26171 282 9.0 6 34.4 75.9 234 1176 3306 ^ \\\ 69.0 47.8 26789 285 8.7 8 36.3 75.9 289 1188 4303 r. 11M 66.0 32.7 28876 303 9.0 6 24.5 74.9 361 1190 4765 4at 70.0 35.0 30018 311 9.0 6 25.9 74.0 343 1197 5378 fnr ρΤΤΓ j \\\ 69.1 47.5 31329 322 9.0 8 34.7 73.1 329 1185 5852 M / \ s \ 69.4 34.7 20534 176 9.0 6 28.5 82.1 290 980 221 dnt Ws 71.3 43.9 24722 228 9.0 8 34.9 79.5 333 1142 3708 flTf 69.8 48.7 31436 306 9.2 8 35.6 73.1 323 1178 5854 4at 71.2 48.3 32594 331 10.1 6 34.8 72.0 272 1183 6290 4τττ Μ 69.6 48.3 32594 6 31.9 66.0 234 973 5172 dnL Μ 63.8 49.0 33272 337 9.0 6 31.3 63.9 233 936 5110 4πτ Μ 62.7 40.0 34990 350 9.0 6 24.5 61.3 307 901 5414 Μ 61.3 40.0 34990 350 11.5 6 27.6 69.0 307 1241 7442 ίΒΕΕ ", 69.0 Reverse osmosis membrane element efficacy Desalination rate: 99.7%, fresh water generation: 5.0 m3 / d, [estimated under the above feed water conditions and a pressure of 5.5 MPa] Fouling inhibitor sodium hexametaphosphate