JPH0141392B2 - - Google Patents
Info
- Publication number
- JPH0141392B2 JPH0141392B2 JP8415983A JP8415983A JPH0141392B2 JP H0141392 B2 JPH0141392 B2 JP H0141392B2 JP 8415983 A JP8415983 A JP 8415983A JP 8415983 A JP8415983 A JP 8415983A JP H0141392 B2 JPH0141392 B2 JP H0141392B2
- Authority
- JP
- Japan
- Prior art keywords
- residual
- water
- exchange resin
- resin layer
- equivalence ratio
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 44
- 150000001768 cations Chemical class 0.000 claims description 25
- 150000001450 anions Chemical class 0.000 claims description 22
- 238000005342 ion exchange Methods 0.000 claims description 12
- -1 hydrogen ions Chemical class 0.000 claims description 10
- 238000000034 method Methods 0.000 claims description 10
- 230000002378 acidificating effect Effects 0.000 claims description 7
- NWUYHJFMYQTDRP-UHFFFAOYSA-N 1,2-bis(ethenyl)benzene;1-ethenyl-2-ethylbenzene;styrene Chemical compound C=CC1=CC=CC=C1.CCC1=CC=CC=C1C=C.C=CC1=CC=CC=C1C=C NWUYHJFMYQTDRP-UHFFFAOYSA-N 0.000 claims description 6
- 239000003957 anion exchange resin Substances 0.000 claims description 6
- 239000003729 cation exchange resin Substances 0.000 claims description 6
- 238000010612 desalination reaction Methods 0.000 claims description 5
- 229910052739 hydrogen Inorganic materials 0.000 claims description 5
- 239000001257 hydrogen Substances 0.000 claims description 5
- 238000012546 transfer Methods 0.000 claims description 4
- VEXZGXHMUGYJMC-UHFFFAOYSA-M Chloride anion Chemical compound [Cl-] VEXZGXHMUGYJMC-UHFFFAOYSA-M 0.000 claims description 2
- 238000009826 distribution Methods 0.000 claims description 2
- FKNQFGJONOIPTF-UHFFFAOYSA-N Sodium cation Chemical compound [Na+] FKNQFGJONOIPTF-UHFFFAOYSA-N 0.000 claims 1
- 238000011033 desalting Methods 0.000 claims 1
- 229910001415 sodium ion Inorganic materials 0.000 claims 1
- 238000001514 detection method Methods 0.000 description 20
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 9
- 239000011734 sodium Substances 0.000 description 9
- 230000007935 neutral effect Effects 0.000 description 6
- 150000002500 ions Chemical class 0.000 description 4
- 238000004519 manufacturing process Methods 0.000 description 4
- 230000008929 regeneration Effects 0.000 description 3
- 238000011069 regeneration method Methods 0.000 description 3
- 150000003839 salts Chemical class 0.000 description 3
- FAPWRFPIFSIZLT-UHFFFAOYSA-M Sodium chloride Chemical compound [Na+].[Cl-] FAPWRFPIFSIZLT-UHFFFAOYSA-M 0.000 description 2
- 239000011575 calcium Substances 0.000 description 2
- 230000001276 controlling effect Effects 0.000 description 2
- 238000007796 conventional method Methods 0.000 description 2
- 239000011777 magnesium Substances 0.000 description 2
- OYPRJOBELJOOCE-UHFFFAOYSA-N Calcium Chemical compound [Ca] OYPRJOBELJOOCE-UHFFFAOYSA-N 0.000 description 1
- DGAQECJNVWCQMB-PUAWFVPOSA-M Ilexoside XXIX Chemical compound C[C@@H]1CC[C@@]2(CC[C@@]3(C(=CC[C@H]4[C@]3(CC[C@@H]5[C@@]4(CC[C@@H](C5(C)C)OS(=O)(=O)[O-])C)C)[C@@H]2[C@]1(C)O)C)C(=O)O[C@H]6[C@@H]([C@H]([C@@H]([C@H](O6)CO)O)O)O.[Na+] DGAQECJNVWCQMB-PUAWFVPOSA-M 0.000 description 1
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- 238000013459 approach Methods 0.000 description 1
- 229910052791 calcium Inorganic materials 0.000 description 1
- 239000003518 caustics Substances 0.000 description 1
- 238000004140 cleaning Methods 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 238000005336 cracking Methods 0.000 description 1
- 238000000354 decomposition reaction Methods 0.000 description 1
- 238000001704 evaporation Methods 0.000 description 1
- 230000008020 evaporation Effects 0.000 description 1
- GPRLSGONYQIRFK-UHFFFAOYSA-N hydron Chemical group [H+] GPRLSGONYQIRFK-UHFFFAOYSA-N 0.000 description 1
- 229910052749 magnesium Inorganic materials 0.000 description 1
- 238000012544 monitoring process Methods 0.000 description 1
- 230000001105 regulatory effect Effects 0.000 description 1
- 238000001223 reverse osmosis Methods 0.000 description 1
- 238000005070 sampling Methods 0.000 description 1
- 229910052708 sodium Inorganic materials 0.000 description 1
- 239000011780 sodium chloride Substances 0.000 description 1
Description
【発明の詳細な説明】
本発明は、脱塩水をイオン交換処理することに
より処理水中に残留するカチオンとアニオンの濃
度比率を所定の値に制御するための方法に関する
ものである。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for controlling the concentration ratio of cations and anions remaining in treated water to a predetermined value by subjecting demineralized water to ion exchange treatment.
従来蒸発法、逆浸透法、イオン交換法などによ
つて原水を脱塩する方法は広く知られている。製
造された脱塩水は種々の用途に使用されるが、使
用目的によつて許容される残存塩類濃度やその他
の水質が異なることは言うまでもない。 Conventional methods of desalinating raw water by evaporation, reverse osmosis, ion exchange, and the like are widely known. The produced desalinated water is used for various purposes, and it goes without saying that the allowable residual salt concentration and other water qualities vary depending on the purpose of use.
上記従来法による脱塩水は必ずしも中性ではな
く、水素イオン以外のカチオン（以下、残存カチ
オンとする）と水酸化物イオン以外のアニオン
（以下、残存アニオンとする）のイオンバランス
がくずれている場合もある。残存カチオンと残存
アニオンの当量比が１より小さい場合には脱塩水
は酸性、１より大きい場合には脱塩水は塩基性と
なる。 Desalinated water obtained by the conventional method described above is not necessarily neutral, and the ion balance of cations other than hydrogen ions (hereinafter referred to as residual cations) and anions other than hydroxide ions (hereinafter referred to as residual anions) is disrupted. There is also. When the equivalent ratio of residual cations to residual anions is less than 1, the demineralized water is acidic, and when it is more than 1, the demineralized water is basic.
たとえば、第１塔に水素イオン（H+）形の強
酸性カチオン交換樹脂（以下、CRとする）を充
填し、第２塔に水酸化物イオン（OH-）形の強
塩基性アニオン交換樹脂（以下、ARとする）を
充填して、原水を第１塔から第２塔へと直列に通
水する「２床式」のイオン交換装置の処理水は通
常は塩基性である。 For example, the first column is filled with a strongly acidic cation exchange resin (hereinafter referred to as CR) in the form of hydrogen ions (H + ), and the second column is filled with a strongly basic anion exchange resin in the form of hydroxide ions (OH - ). (hereinafter referred to as AR), the treated water of the "two-bed type" ion exchange equipment, in which raw water is passed in series from the first column to the second column, is usually basic.
これは、第１塔のH+形CRが完全に再生されて
おらず一部がナトリウム（Na+）形、マグネシウ
ム（Mg2+）形、カルシウム（Ca2+）形などの負
荷形になつているため、通水時に第１塔からおも
にNa+がリークし、これが第２塔を素通りして第
２塔の流出水中に存在することによる。第２塔か
らの塩素イオン（Cl-）などのリークは通常Na+
リークに比較して非常に小さいので、結果として
第２塔からの流出水中には水酸化ナトリウム
（NaOH）が存在することになり処理水は塩基性
を呈するのである。 This is because the H + form CR in the first column is not completely regenerated and some of it becomes loaded forms such as sodium (Na + ) form, magnesium (Mg 2+ ) form, and calcium (Ca 2+ ) form. Therefore, Na + mainly leaks from the first tower during water flow, which passes through the second tower and is present in the outflow water of the second tower. Leakage of chloride ions (Cl - ) from the second column is usually caused by Na +
Since it is very small compared to the leakage, as a result, sodium hydroxide (NaOH) is present in the water flowing out from the second tower, and the treated water becomes basic.
上記２床式のイオン交換装置の処理水を中性に
するためには第２塔の後段にH+形の弱酸性カチ
オン交換樹脂（以下、WCRとする）を設ければ
よいとされている。H+形のWCRは第２塔の流出
水中のアルルカリ度成分だけを吸着除去し、中性
塩を構成するカチオンは吸着除去しないとされて
いるので、その処理水は中性になる。しかしなが
ら、WCRもわずかながら中性塩分解能力を持つ
ことが多く、その場合には処理水は微酸性とな
る。さらにWCRは酸による再生後の洗浄特性が
悪いために再生後はしばらく処理水が酸性とな
り、その後通水を続けていると次第に処理水が中
性となつてくるという傾向がある。 In order to neutralize the treated water of the two-bed ion exchange equipment mentioned above, it is said that it is sufficient to install an H + type weakly acidic cation exchange resin (hereinafter referred to as WCR) at the latter stage of the second column. . It is said that the H + form of WCR adsorbs and removes only the alkaline alkalinity component in the water flowing out of the second column, and does not adsorb and remove the cations that make up the neutral salts, so the treated water becomes neutral. However, WCR also often has a small amount of neutral salt decomposition ability, and in that case, the treated water becomes slightly acidic. Furthermore, since WCR has poor cleaning properties after regeneration with acid, the treated water tends to become acidic for a while after regeneration, and then gradually become neutral as water continues to flow through it.
このような場合、WCRを後段に設ける代わり
に本発明を用れば、処理水を常に中性に保つこと
ができる。 In such a case, if the present invention is used instead of providing a WCR in the latter stage, the treated water can always be kept neutral.
次に、脱塩水がボイラ給水として使用される場
合に本発明を応用することについて説明する。よ
く知られているように、高圧ボイラにおいては
Na+はタービンスケールや苛性脆化の原因となり
Cl-は応力腐食割れの原因になるとされており、
ボイラ給水中のNa+濃度とCl-濃度は厳しく規制
されることが多い。この場合、Na+の存在環境が
問題であるとする見解もある。すなわちNaClと
して存在するか、NaOHとして存在するかによ
つて、ボイラ内における挙動が異なつてくるとい
う見解である。こうなると、Na+とCl-の当量比
が問題となる。 Next, application of the present invention to a case where desalinated water is used as boiler feed water will be described. As is well known, in high pressure boilers
Na + causes turbine scale and caustic embrittlement.
Cl - is said to cause stress corrosion cracking,
Na + and Cl - concentrations in boiler feedwater are often strictly regulated. In this case, there is a view that the problem is the environment in which Na + exists. In other words, the idea is that the behavior within the boiler differs depending on whether it exists as NaCl or NaOH. In this case, the equivalence ratio of Na + and Cl - becomes a problem.
このような場合に本発明を用いれば、Na+と
Cl-の当量比を広範囲にわたつて所望の値に制御
することが可能となる。 If the present invention is used in such a case, Na + and
It becomes possible to control the equivalent ratio of Cl - to a desired value over a wide range.
本発明は、原水を脱塩工程で処理したのちイオ
ン交換工程で処理する方法において、前記イオン
交換工程を前記脱塩工程による脱塩水の移送ライ
ン、水素イオン形の強酸性カチオン交換樹脂層及
び水酸化物イオン形の強塩基性アニオン交換樹脂
層を並列に配備して形成すると共に、該イオン交
換工程からの流出水について水素イオン以外の残
留カチオンと水酸化物イオン以外の残留アニオン
の当量比を測定し、目標とする当量比と前記測定
当量比の差がなくなるように該測定当量比に基づ
いて前記イオン交換工程へ流入する前記脱塩水の
前記カチオン交換樹脂層、アニオン交換樹脂層及
び移送ラインへの分配供給流量の比率を設定する
ことを特徴とする脱塩水中の残存カチオンと残存
アニオンの存在比率の制御方法である。 The present invention provides a method in which raw water is treated in a desalination process and then treated in an ion exchange process, in which the ion exchange process is performed in a transfer line for desalted water from the desalination process, a strongly acidic cation exchange resin layer in the hydrogen ion form, and a water In addition to forming strongly basic anion exchange resin layers in the form of oxide ions in parallel, the equivalent ratio of residual cations other than hydrogen ions and residual anions other than hydroxide ions in the water effluent from the ion exchange process is determined. The cation exchange resin layer, the anion exchange resin layer, and the transfer line of the desalted water that is measured and flows into the ion exchange step based on the measured equivalence ratio so that there is no difference between the target equivalence ratio and the measured equivalence ratio. This is a method for controlling the abundance ratio of residual cations and residual anions in demineralized water, which is characterized by setting the ratio of the distribution and supply flow rate to the demineralized water.
以下に、図面を用いて本発明の一実施態様を説
明する。図において１は脱塩水製造装置、２は
H+形のCR層、３はOH-の形のAR層、４はカチ
オン濃度検出手段、５はアニオン濃度検出手段、
６は流量制御装置、７，８，９は流量検出手段、
１０，１１，１２は流量制御弁である。 An embodiment of the present invention will be described below with reference to the drawings. In the figure, 1 is a desalinated water production device, and 2 is a desalinated water production device.
CR layer of H + type, 3 AR layer of OH - type, 4 cation concentration detection means, 5 anion concentration detection means,
6 is a flow rate control device; 7, 8, 9 are flow rate detection means;
10, 11, and 12 are flow rate control valves.
しかして脱塩水製造装置１によつて製造された
脱塩水は弁１０、流量検出手段７、カチオン濃度
検出手段４、アニオン濃度検出手段５を通つて流
れる。カチオン濃度検出手段４、アニオン濃度検
出手段５によつて測定されたカチオン濃度とアニ
オン濃度は流量制御装置６に伝えられ、もしカチ
オンとアニオンの当量比が所望の値よりも小さい
場合には、弁１２が少し開き弁１０が少し閉じる
ことによつて脱塩水の一部がOH-形AR層３にバ
イパスされる。その結果はカチオン濃度検出手段
４、アニオン濃度検出手段５によつて測定され、
その結果によつて弁１０と弁１２の開き加減が調
節される。このようなフイードバツク制御によ
り、カチオンとアニオンの当量比は所望の値に近
づく。 Thus, the desalted water produced by the desalted water production apparatus 1 flows through the valve 10, the flow rate detection means 7, the cation concentration detection means 4, and the anion concentration detection means 5. The cation concentration and anion concentration measured by the cation concentration detection means 4 and the anion concentration detection means 5 are transmitted to the flow rate control device 6, and if the equivalence ratio of cations and anions is smaller than a desired value, the By slightly opening valve 12 and slightly closing valve 10, a portion of the desalinated water is bypassed to the OH - type AR layer 3. The results are measured by cation concentration detection means 4 and anion concentration detection means 5,
Depending on the result, the degree of opening of the valves 10 and 12 is adjusted. Through such feedback control, the equivalence ratio of cations and anions approaches a desired value.
脱塩水中のカチオンとアニオンの当量比が１よ
りも大きい場合には、弁１１が少し開き弁１０が
少し閉じることによつて脱塩水の一部がH+形CR
層２ににバイパスされる。なお流量検出手段７，
８，９は流量制御が正常に動作しているかを確認
するためのものであり、この情報も流量制御装置
６に伝えられる。 When the equivalence ratio of cations and anions in the desalinated water is greater than 1, the valve 11 opens slightly and the valve 10 closes slightly, so that a portion of the desalted water becomes H +
Bypassed to layer 2. Note that the flow rate detection means 7,
Reference numerals 8 and 9 are used to confirm whether the flow rate control is operating normally, and this information is also transmitted to the flow rate control device 6.
前記H+形のCR層２およびOH-形のAR層３は
向流再生し、かつ再生レベルを高くとることによ
つて、それぞれカチオンおよびアニオンのリーク
をできるだけ小さくすることが好ましい。カチオ
ン濃度検出手段４としては、完全再生したOH-
形のAR層に脱塩水を通した後の導電率を測定す
る方法や、イオン選択性電極を用いたイオンメー
タなどがある。また、このように連続的にモニタ
リングせずに、間欠的にサンプリングしてカチオ
ンを分析してもよい。すなわち本発明ではカチオ
ン濃度検出手段４については特に限定されない。
同様にアニオン濃度検出手段５についても特に限
定されない。 It is preferable that the H + -type CR layer 2 and the OH - -type AR layer 3 be regenerated in countercurrent and at a high regeneration level to minimize the leakage of cations and anions, respectively. As the cation concentration detection means 4, completely regenerated OH -
There are methods that measure the conductivity after passing demineralized water through a shaped AR layer, and ion meters that use ion-selective electrodes. Alternatively, cations may be analyzed by sampling intermittently, without continuous monitoring in this way. That is, in the present invention, the cation concentration detection means 4 is not particularly limited.
Similarly, the anion concentration detection means 5 is not particularly limited either.
前記流量制御装置６はカチオン濃度検出手段
４、アニオン濃度検出手段５、流量検出手段７，
８，９からの情報を受けて弁１０，１１，１２
（自動制御弁が好ましいが、手動弁としてもよい）
を操作し各流路に流れる流量を制御する。 The flow rate control device 6 includes a cation concentration detection means 4, an anion concentration detection means 5, a flow rate detection means 7,
Valve 10, 11, 12 receives information from 8, 9
(An automatic control valve is preferred, but a manual valve may also be used.)
to control the flow rate flowing into each channel.
なお、本発明が上記実施態様に限定されるもの
でないことは勿論である。 Note that, of course, the present invention is not limited to the above embodiments.
以上本発明によれば、脱塩水中の残存カチオン
と残存アニオンの存在比率を広範囲にわたつて所
望の値に簡便かつ適確に制御することができる実
益がある。 As described above, according to the present invention, there is a practical advantage that the abundance ratio of residual cations and residual anions in demineralized water can be easily and accurately controlled to a desired value over a wide range.
図面は、本発明の一実施態様を示すフローシー
トである。
１……脱塩水製造装置、２……CR層、３……
AR層、４……カチオン濃度検出手段、５……ア
ニオン濃度検出手段、６……流量制御装置、７，
８，９……流量検出手段、１０，１１，１２……
弁。
The drawing is a flow sheet illustrating one embodiment of the invention. 1...Demineralized water production device, 2...CR layer, 3...
AR layer, 4...Cation concentration detection means, 5...Anion concentration detection means, 6...Flow rate control device, 7,
8, 9...Flow rate detection means, 10, 11, 12...
valve.
Claims (1)
程で処理する方法において、前記イオン交換工程
を前記脱塩工程による脱塩水の移送ライン、水素
イオン形の強酸性カチオン交換樹脂層及び水酸化
物イオン形の強塩基性アニオン交換樹脂層を並列
に配備して形成すると共に、該イオン交換工程か
らの流出水について水素イオン以外の残留カチオ
ンと水酸化物イオン以外の残留アニオンの当量比
を測定し、目標とする当量比と前記測定当量比の
差がなくなるように該測定当量比に基づいて前記
イオン交換工程へ流入する前記脱塩水の前記カチ
オン交換樹脂層、アニオン交換樹脂層及び移送ラ
インへの分配供給流量の比率を設定することを特
徴とする脱塩水中の残存カチオンと残存アニオン
の存在比率の制御方法。 ２ 前記脱塩工程がイオン交換工程である特許請
求の範囲第１項記載の方法。 ３ 前記脱塩工程が復水を処理するものである特
許請求の範囲第１項記載の方法。 ４ 前記残留カチオンがナトリウムイオンであ
り、前記残留アニオンが塩素イオンである特許請
求の範囲第１項記載の方法。[Scope of Claims] 1. In a method in which raw water is treated in a desalination process and then treated in an ion exchange process, the ion exchange process is performed in a transfer line for desalinated water from the desalination process, and a strongly acidic cation exchange resin in the form of hydrogen ions. The strong basic anion exchange resin layer in the form of hydroxide ions is arranged in parallel to form a strong base anion exchange resin layer, and the residual cations other than hydrogen ions and the residual anions other than hydroxide ions are The cation exchange resin layer and the anion exchange resin layer of the demineralized water flowing into the ion exchange step based on the measured equivalence ratio so that the equivalence ratio is measured and there is no difference between the target equivalence ratio and the measured equivalence ratio. and a method for controlling the abundance ratio of residual cations and residual anions in demineralized water, the method comprising setting the ratio of the distribution and supply flow rate to the transfer line. 2. The method according to claim 1, wherein the desalting step is an ion exchange step. 3. The method according to claim 1, wherein the desalination step treats condensate. 4. The method according to claim 1, wherein the residual cation is a sodium ion and the residual anion is a chloride ion.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP8415983A JPS59209697A (en) | 1983-05-16 | 1983-05-16 | Controlling method for existence ratio of cation and anion remaining in desalinated water |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP8415983A JPS59209697A (en) | 1983-05-16 | 1983-05-16 | Controlling method for existence ratio of cation and anion remaining in desalinated water |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS59209697A JPS59209697A (en) | 1984-11-28 |
| JPH0141392B2 true JPH0141392B2 (en) | 1989-09-05 |
Family
ID=13822714
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP8415983A Granted JPS59209697A (en) | 1983-05-16 | 1983-05-16 | Controlling method for existence ratio of cation and anion remaining in desalinated water |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS59209697A (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR101017918B1 (en) | 2008-11-14 | 2011-03-04 | 박병호 | Method for producing ion reduced water using ion exchange resin |
-
1983
- 1983-05-16 JP JP8415983A patent/JPS59209697A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS59209697A (en) | 1984-11-28 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| AU2009244243B2 (en) | Method of minimizing corrosion, scale, and water consumption in cooling tower systems | |
| US5997745A (en) | Method for producing high purity water using triple pass reverse osmosis (TPRO) | |
| US6120689A (en) | High purity water using triple pass reverse osmosis (TPRO) | |
| US4276180A (en) | Industrial waste-water reuse by selective silica removal over activated alumina | |
| US6126834A (en) | High resistivity water production with controlled water temperatures | |
| US7618538B2 (en) | Procedure for elimination of boron from sea-water by reverse osmosis membranes | |
| US3223620A (en) | Corrosion inhibition | |
| Migliorini et al. | Seawater reverse osmosis plant using the pressure exchanger for energy recovery: a calculation model | |
| JPH1085743A (en) | Method and apparatus for treating water containing boron | |
| WO2011163361A1 (en) | Water treatment method and apparatus | |
| US5096589A (en) | Hydrogen sulfide removal from reverse osmosis product water | |
| JPH0141392B2 (en) | ||
| Rice et al. | Threshold Treatment of Municipal Water Supplies: Use of Sodium Hexametaphosphate | |
| JP3278918B2 (en) | Desalting method | |
| Thompson et al. | Ion-Exchange Treatment of Water Supplies [with Discussion] | |
| IL25055A (en) | Process of removing a component from a fluid | |
| JP2022015198A (en) | Treatment method of water with hardness and treatment device of water with hardness | |
| JP2005118712A (en) | Pure water manufacturing method | |
| US11008230B2 (en) | Exchange based-water treatment | |
| Zhu et al. | Prevention of calcium sulfate formation in seawater desalination by ion exchange | |
| Applegate | Posttreatment of reverse osmosis product waters | |
| JP7261711B2 (en) | Ultrapure water production system and ultrapure water production method | |
| US2701791A (en) | Water softening process | |
| WO2021140824A1 (en) | Water treatment method and device for boilers | |
| JPS6150675B2 (en) |