JPS6255898B2 - - Google Patents
Info
- Publication number
- JPS6255898B2 JPS6255898B2 JP57144799A JP14479982A JPS6255898B2 JP S6255898 B2 JPS6255898 B2 JP S6255898B2 JP 57144799 A JP57144799 A JP 57144799A JP 14479982 A JP14479982 A JP 14479982A JP S6255898 B2 JPS6255898 B2 JP S6255898B2
- Authority
- JP
- Japan
- Prior art keywords
- exchange resin
- resin
- inorganic acid
- iron removal
- reducing agent
- 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
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 78
- MUBZPKHOEPUJKR-UHFFFAOYSA-N Oxalic acid Chemical compound OC(=O)C(O)=O MUBZPKHOEPUJKR-UHFFFAOYSA-N 0.000 claims description 58
- 229910052742 iron Inorganic materials 0.000 claims description 39
- 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 31
- 150000007522 mineralic acids Chemical class 0.000 claims description 28
- 239000003957 anion exchange resin Substances 0.000 claims description 26
- 239000003638 chemical reducing agent Substances 0.000 claims description 24
- 239000003729 cation exchange resin Substances 0.000 claims description 23
- 239000011347 resin Substances 0.000 claims description 22
- 229920005989 resin Polymers 0.000 claims description 22
- 238000011069 regeneration method Methods 0.000 claims description 21
- 238000000034 method Methods 0.000 claims description 19
- 230000008929 regeneration Effects 0.000 claims description 19
- 235000006408 oxalic acid Nutrition 0.000 claims description 17
- 239000003456 ion exchange resin Substances 0.000 claims description 14
- 229920003303 ion-exchange polymer Polymers 0.000 claims description 14
- 150000003839 salts Chemical class 0.000 claims description 11
- 239000007788 liquid Substances 0.000 claims description 8
- 239000011259 mixed solution Substances 0.000 claims description 8
- 238000005253 cladding Methods 0.000 claims description 5
- 230000001172 regenerating effect Effects 0.000 claims description 5
- 239000000203 mixture Substances 0.000 description 15
- CIWBSHSKHKDKBQ-JLAZNSOCSA-N Ascorbic acid Chemical compound OC[C@H](O)[C@H]1OC(=O)C(O)=C1O CIWBSHSKHKDKBQ-JLAZNSOCSA-N 0.000 description 13
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 12
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 11
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 9
- 238000010612 desalination reaction Methods 0.000 description 9
- 230000000694 effects Effects 0.000 description 8
- UQSXHKLRYXJYBZ-UHFFFAOYSA-N Iron oxide Chemical compound [Fe]=O UQSXHKLRYXJYBZ-UHFFFAOYSA-N 0.000 description 6
- RAHZWNYVWXNFOC-UHFFFAOYSA-N Sulphur dioxide Chemical compound O=S=O RAHZWNYVWXNFOC-UHFFFAOYSA-N 0.000 description 6
- 229910021529 ammonia Inorganic materials 0.000 description 6
- 239000003795 chemical substances by application Substances 0.000 description 6
- 150000001875 compounds Chemical class 0.000 description 6
- 230000008569 process Effects 0.000 description 6
- 235000010350 erythorbic acid Nutrition 0.000 description 5
- 238000012545 processing Methods 0.000 description 5
- 239000000126 substance Substances 0.000 description 5
- FAPWRFPIFSIZLT-UHFFFAOYSA-M Sodium chloride Chemical compound [Na+].[Cl-] FAPWRFPIFSIZLT-UHFFFAOYSA-M 0.000 description 4
- 239000002253 acid Substances 0.000 description 4
- CIWBSHSKHKDKBQ-DUZGATOHSA-N D-araboascorbic acid Natural products OC[C@@H](O)[C@H]1OC(=O)C(O)=C1O CIWBSHSKHKDKBQ-DUZGATOHSA-N 0.000 description 3
- 239000002211 L-ascorbic acid Substances 0.000 description 3
- 235000000069 L-ascorbic acid Nutrition 0.000 description 3
- 229960005070 ascorbic acid Drugs 0.000 description 3
- 239000004318 erythorbic acid Substances 0.000 description 3
- 238000002474 experimental method Methods 0.000 description 3
- 229940026239 isoascorbic acid Drugs 0.000 description 3
- 238000002156 mixing Methods 0.000 description 3
- 235000011121 sodium hydroxide Nutrition 0.000 description 3
- -1 H 2 SO 4 Chemical compound 0.000 description 2
- 238000009835 boiling Methods 0.000 description 2
- 229940023913 cation exchange resins Drugs 0.000 description 2
- 238000007796 conventional method Methods 0.000 description 2
- 229940079593 drug Drugs 0.000 description 2
- 239000003814 drug Substances 0.000 description 2
- 229940026231 erythorbate Drugs 0.000 description 2
- 229940062993 ferrous oxalate Drugs 0.000 description 2
- 235000003891 ferrous sulphate Nutrition 0.000 description 2
- 239000011790 ferrous sulphate Substances 0.000 description 2
- 150000002500 ions Chemical class 0.000 description 2
- BAUYGSIQEAFULO-UHFFFAOYSA-L iron(2+) sulfate (anhydrous) Chemical compound [Fe+2].[O-]S([O-])(=O)=O BAUYGSIQEAFULO-UHFFFAOYSA-L 0.000 description 2
- OWZIYWAUNZMLRT-UHFFFAOYSA-L iron(2+);oxalate Chemical compound [Fe+2].[O-]C(=O)C([O-])=O OWZIYWAUNZMLRT-UHFFFAOYSA-L 0.000 description 2
- 229910000359 iron(II) sulfate Inorganic materials 0.000 description 2
- 238000011160 research Methods 0.000 description 2
- 238000005070 sampling Methods 0.000 description 2
- 239000011780 sodium chloride Substances 0.000 description 2
- 239000007787 solid Substances 0.000 description 2
- 239000000243 solution Substances 0.000 description 2
- 238000003756 stirring Methods 0.000 description 2
- XTQHKBHJIVJGKJ-UHFFFAOYSA-N sulfur monoxide Chemical class S=O XTQHKBHJIVJGKJ-UHFFFAOYSA-N 0.000 description 2
- 229910052815 sulfur oxide Inorganic materials 0.000 description 2
- 239000002699 waste material Substances 0.000 description 2
- 229910000859 α-Fe Inorganic materials 0.000 description 2
- 229910006299 γ-FeOOH Inorganic materials 0.000 description 2
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 1
- 230000002378 acidificating effect Effects 0.000 description 1
- 230000009471 action Effects 0.000 description 1
- 150000001450 anions Chemical class 0.000 description 1
- 238000011001 backwashing Methods 0.000 description 1
- 125000002091 cationic group Chemical group 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 230000002542 deteriorative effect Effects 0.000 description 1
- 238000004090 dissolution Methods 0.000 description 1
- GRWZHXKQBITJKP-UHFFFAOYSA-L dithionite(2-) Chemical compound [O-]S(=O)S([O-])=O GRWZHXKQBITJKP-UHFFFAOYSA-L 0.000 description 1
- 230000000666 effect on cation Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000001125 extrusion Methods 0.000 description 1
- 239000000945 filler Substances 0.000 description 1
- 238000005342 ion exchange Methods 0.000 description 1
- 150000002505 iron Chemical class 0.000 description 1
- 150000002506 iron compounds Chemical class 0.000 description 1
- RUTXIHLAWFEWGM-UHFFFAOYSA-H iron(3+) sulfate Chemical compound [Fe+3].[Fe+3].[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O RUTXIHLAWFEWGM-UHFFFAOYSA-H 0.000 description 1
- 229910000360 iron(III) sulfate Inorganic materials 0.000 description 1
- 230000007774 longterm Effects 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 238000010979 pH adjustment Methods 0.000 description 1
- 238000000746 purification Methods 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 238000011946 reduction process Methods 0.000 description 1
- 239000012492 regenerant Substances 0.000 description 1
- 238000005201 scrubbing Methods 0.000 description 1
- 235000011149 sulphuric acid Nutrition 0.000 description 1
- 230000008685 targeting Effects 0.000 description 1
- 238000002525 ultrasonication Methods 0.000 description 1
- 238000005406 washing Methods 0.000 description 1
- 229910006540 α-FeOOH Inorganic materials 0.000 description 1
Landscapes
- Treatment Of Water By Ion Exchange (AREA)
Description
本発明は、イオン交換樹脂に付着したクラツド
すなわち酸化鉄等の鉄化合物を主体とする腐蝕生
成物を除去する方法に関するものであり、クラツ
ドを効率的に除去すると共に、取扱いが容易でか
つその後の運転に好適な除去方法(以下、「除鉄
回生方法」と記す)を提供することを目的とする
ものである。
クラツドがイオン交換樹脂に付着すると、交換
容量が低下するだけでなくクラツドが恒常的に漏
出し処理水質が悪化する。特に問題となるのは火
力発電所、原子力発電所で用いられている浄化系
の復水脱塩装置においてクラツドの付着が生ずる
場合である。復水脱塩装置のイオン交換樹脂に付
着するクラツドは磁性酸化鉄(Fe3O4+γ−
Fe2O3)、α−Fe2O3、γ−FeOOH、α−FeOOH
及び非晶質のものに概略分けられる。火力発電所
では磁性酸化鉄、γ−FeOOH、非晶質のものの
三つが主体であるといわれている。カチオン交換
樹脂は再生毎にH2SO4、HCl等で再生されるため
付着クラツド量は500mg/−RasFe以下の場合
が多い。しかし、アニオン交換樹脂においては、
付着クラツドは再生剤(苛性ソーダ)では除去さ
れにくく、しだいに蓄積していき1000〜1500mg/
−RasFeに達する場合もある。付着しているク
ラツドの形態はカチオン交換樹脂、アニオン交換
樹脂によつて異なるといわれるがその詳細は不明
である。
沸騰水型の原子力発電所ではα−Fe2O3の割合
が大きく、またクラツドの大部分はカチオン交換
樹脂によつて除去されており、カチオン交換樹脂
のクラツド付着量は10000〜30000mg/−RasFe
に達する場合もある。アニオン交換樹脂にクラツ
ドが付着する割合は極く小さいが火力発電所の場
合と同様徐々に蓄積していく。このようにクラツ
ド付着量が多くなると処理水へのクラツドの漏出
も恒常的に高くなつていく。
これら付着しているクラツドは、逆洗あるいは
エアスクラビングを頻繁に行つても除去される割
合は極くわずかである。現在火力発電所ではクラ
ツド付着量が500mg/−RasFe程度以上になる
と薬品(除鉄回生剤)による除鉄回生処理が行わ
れ、硫黄酸化物を主体とするもの例えばハイドロ
サルフアイト、Na2SO3、NaHSO3等の還元剤を
イオン交換樹脂に接触させ、付着しているクラツ
ドを還元し可溶性の鉄として除去することが行わ
れている。
従来の一般的な除鉄回生処理工程は下記の如く
である。
(1) 樹脂イオン型調整のためオチオン交換樹脂、
アニオン交換樹脂に対して同一の塔でNaClを
投入しそれぞれNa型、Cl型にする。
(2) マンホールより固形状の還元剤を投入し還元
処理を数時間行う。この時、苛性ソーダあるい
はH2SO4、HClを用いてPH調整を厳密に行う。
これは酸性サイドに傾くと大量の亜硫酸ガスが
発生すること、またアルカリサイドになつて除
鉄効果がかなり小さくなること等を防止するた
めである。イオン交換樹脂と上記還元剤とを数
時間接触させたのちに押出、洗浄を行う。クラ
ツドはこの工程で可溶性の鉄として樹脂より液
中に溶出し除去される。
(3) 混合樹脂を逆洗分離しカチオン交換樹脂は
H2SO4、HClでアニオン交換樹脂は通常再生レ
ベルの2〜3倍量でそれぞれ再生する。
しかしながら、この除鉄回生方法には次のよう
な欠点がある。
(イ) 硫黄酸化物を主体とする還元剤は不安定であ
り溶液として保存することができず固形で取扱
うため、再生塔のマンホールの開閉の操作が必
要となり作業性が悪い。また、特にその溶解時
あるいはPH調整時に多量の亜硫酸ガスが発生し
作業上かなり問題となる。
(ロ) カチオン交換樹脂、アニオン交換樹脂を同時
に処理していると、前記(2)の工程でアニオン交
換樹脂よりはくり・還元された鉄イオンがカチ
オン交換樹脂とイオン交換し、かえつて還元処
理前よりカチオン交換樹脂の鉄量が増え、この
除去に多量の無機酸が必要となるとともに除鉄
効果が小さくなつてしまう。
(ハ) NaCl処理を行いNa型、Cl型にわざわざ変換
するため、前記(3)の再生工程によつてもNa
型、Cl型が多量残留し、その後の採水におい
てアンモニアサイクルを実施すると多量の
Na、Clのリークが生ずる。これを避けるため
除鉄回生後の5サイクル程度、約1ケ月間はH
−OHサイクルで運転しNa型、Cl型の減少した
のを見計つてアンモニアサイクルに移行してい
る。すなわち、除鉄回生処理によつてその後の
運転に大きい制約を受けている。
沸騰水型原子力発電所では火力発電所で用いら
れている還元剤の入つた除鉄回生剤によつて処理
することは行われていない。これは除鉄回生剤に
含まれるNa、KあるいはCl、SO4等のイオンによ
りNa型、Cl型等の塩型となるため塩型の再生に
多量の再生剤が必要となり再生廃液量が多くなる
こと、Clの漏出量等があり火力発電所より厳し
い処理水質の達成が困難となること等による。現
在超音波処理によるクラツド除去が実験的に行わ
れているがその効果は小さく、実用化するには更
に長期の研究が必要である。
本発明者らは火力発電所の復水脱塩装置の実機
で使われているイオン交換樹脂を主な対象とし
て、前記欠点を解消する効果的な除鉄回生剤につ
いて鋭意研究した結果シユウ酸、還元剤及び無機
酸を用いることにより効果的に除鉄回生ができる
ことを見い出した。
すなわち、
(1) シユウ酸単独ではカチオン交換樹脂に対して
30〜40%の除鉄率が得られるが、アニオン交換
樹脂に対してはその除鉄率は小さく10%以下で
ある。
(2) シユウ酸と無機酸の混合液ではシユウ酸単独
より効果があり、カチオン交換樹脂に対して除
鉄率40〜50%を示す。しかし、(1)と同様にアニ
オン交換樹脂に対しては効果が小さい。
(3) シユウ酸あるいはシユウ酸と無機酸の混合液
で処理したのち、更に無機酸を通薬することに
よりカチオン交換樹脂はH2SO4で70〜80%、
HCl、HNO3で90%以上除去できる。しかしア
ニオン交換樹脂に対しては(1)、(2)と同様効果が
小さい。
このようにアニオン交換樹脂に対する除鉄効果
が不充分なのは、カチオン交換樹脂とアニオン交
換樹脂では、これらに付着しているクラツドの形
態がかなり異なるためである。本発明者らはアニ
オン交換樹脂に対しても除鉄効果のあるものを見
い出すべく更に実験し、下記の結果を得た。
(4) 還元剤としてL−アスコルビン酸又はエリソ
ルビン酸を用い、この還元剤とシユウ酸と無機
酸との混合液で十数時間〜数日間処理したのち
無機酸を通薬すると、アニオン交換樹脂の除鉄
率は90%以上となる。
(5) 更に強い還元剤であるNa2SO3、NaHSO3を
用い、この還元剤とシユウ酸との混合液あるい
はこれらと無機酸との混合液で数時間処理した
のち無機酸を通薬すると、アニオン交換樹脂の
除鉄率は90%以上となる。
(6) カチオン交換樹脂に対してもシユウ酸と還元
剤との混合液またはシユウ酸と還元剤と無機酸
との混合液で処理したのち無機酸を通薬するこ
とにより、除鉄率は無機酸がH2SO4の場合でも
80〜90%となる。
(7) 以上の処理においては、シユウ酸の代りにシ
ユウ酸塩を用い、還元剤としてL−アスコルビ
ン酸塩またはエリソルビン酸塩を用いてもその
効果はかわらない。
本発明は、以上のような基本的知見に基づいて
完成されたものである。すなわち本発明は、シユ
ウ酸、シユウ酸塩の少なくとも一方と還元剤との
混合液、又はシユウ酸、シユウ酸塩の少なくとも
一方と還元剤と無機酸との混合液で数十分間〜数
日間処理したのち無機酸を通薬することによつ
て、付着しているクラツドを除去することを特徴
とするものである。
本発明は、従来法が還元剤の作用により一度に
クラツドを溶解性のものとして除去するのに対
し、クラツドをシユウ酸第一鉄等の溶解度の低い
化合物としたのち、無機酸によつてこの化合物を
溶解除去するものである。
本発明を用いて復水脱塩装置のイオン交換樹脂
を除鉄回生処理する場合には次のように行う。
処理対象の樹脂がカチオン交換樹脂の場合は、
これが前記除鉄回生処理時に塩型にならないよう
に還元剤として塩の形でないもの、例えばL−ア
スコルビン酸、エリソルビン酸のような酸の形の
ものを用いるのが好ましく、これらの還元剤とシ
ユウ酸とH2SO4(無機酸としてはアンモニアサイ
クルを運転する場合H2SO4が好ましい)との混合
液で十数時間〜数日間処理したのちH2SO4を通薬
する。このようにするとカチオン交換樹脂は全く
塩型となることなく除鉄回生される。
一方、アニオン交換樹脂について処理する場合
は、これが塩型とならないようにすることはでき
ないためシユウ酸、シユウ酸塩の少なくとも一方
と、無機酸と、そして還元剤として前記酸の形の
ものに限らずNa2SO3、NaHSO3、L−アスコル
ビン酸塩、エリソルビン酸塩のような塩の形のも
のを利用してもよい。Na2SO3、NaHSO3を用い
る時は混合液のPHを2以下にすることにより数十
分〜数時間処理したのち無機酸を通薬することに
より除鉄率は90%以上が得られる。しかし処理中
に亜硫酸ガスが発生するので取扱いに注意を要す
る。なお、従来法においてはNa2SO3、NaHSO3
を用いても除鉄率は低く50%以下である。
L−アスコルビン酸やその塩、エリソルビン酸
やその塩を用いる場合はその還元力が弱いため、
数時間〜数日間の混合液による処理を行うことが
好ましい。
カチオン交換樹脂、アニオン交換樹脂共に混合
液はシユウ酸、シユウ酸塩の少なくとも一方が
0.1〜8%(1〜160g/−R)、還元剤が0.1〜
10%(1〜200g/−R)、無機酸が0.5〜15%
になるように混合溶解し、前述の如く還元剤の種
類に応じて適当な時間撹拌し放置する。この混合
液中ではクラツドは用いた無機酸に応じて例えば
H2SO4の場合は一部硫酸第一鉄等の形で溶解する
が溶解している量は全体の約30%までであり、残
りはシユウ酸第一鉄等の形の溶解度の低い化合物
として樹脂層に付着する。次いでこの混合液を排
出し、無機酸の濃度を1〜10%とし、200〜400
g/−RasCaCO3通薬すると前記溶解度の低い
化合物が硫酸第一鉄及び硫酸第二鉄等になつて完
全に除去される。
この時アニオン交換樹脂は、用いる無機酸に応
じてSO4型、Cl型等に変わる。復水脱塩装置にお
いてはアンモニアサイクル等の運転時に、Naだ
けでなくアニオンの漏出もできるだけ低減する必
要があり、アニオン交換樹脂はCl型の場合より
SO4型となつている方がアンモニアサイクル時の
漏出量が少ないこと、また苛性ソーダによる再生
もCl型よりSO4型の方が非常に再生し易いことか
ら、無機酸としてH2SO4を用いるのが好都合であ
る。
本発明では、イオン交換樹脂が混合樹脂である
場合には、無機酸としてH2SO4を用い通薬を下記
の如く行うのが好ましい。
混合樹脂を逆洗分離し、各樹脂をそれぞれ別
個の再生塔に移送する。
各樹脂を別個に前記混合液で処理する。
ついでカチオン交換樹脂にH2SO4を通薬し
て、これをH型へ再生すると共に前記溶解度の
低い化合物の除去を行う。この通薬後の再生廃
液をアニオン交換樹脂に通薬してこれをSO4型
へ変換すると共に前記溶解度の低い化合物を除
去する。
次に、本発明の実施例について記す。
実施例 1
復水脱塩装置の実機で使用中のアニオン交換樹
脂について除鉄回生処理を行つた。
処理前におけるアニオン交換樹脂の鉄付着量は
650mg/−R(OH型)である。処理用混合液
の種類は第1表のとおりで、いずれの処理方法に
おいても各混合液の成分としての各単品薬品の樹
脂に対する割合は樹脂1に対し100gとし、樹
脂と混合液の混合物試料の総体積を2とした。
また、いずれの処理方法においても樹脂にまず
H2SO4を添加してこれをSO4型としたのち他の薬
品を加えた。
The present invention relates to a method for removing crud adhering to ion exchange resins, that is, corrosion products mainly composed of iron compounds such as iron oxide. The purpose of this is to provide a removal method suitable for operation (hereinafter referred to as "iron removal regeneration method"). When crud adheres to the ion exchange resin, not only does the exchange capacity decrease, but the crud permanently leaks out, deteriorating the quality of treated water. A particular problem arises when crud adhesion occurs in condensate desalination equipment for purification systems used in thermal power plants and nuclear power plants. The crud that adheres to the ion exchange resin of the condensate desalination equipment is magnetic iron oxide (Fe 3 O 4 +γ−
Fe 2 O 3 ), α−Fe 2 O 3 , γ−FeOOH, α−FeOOH
It is roughly divided into amorphous and amorphous. It is said that the three main materials used in thermal power plants are magnetic iron oxide, γ-FeOOH, and amorphous. Since the cation exchange resin is regenerated with H 2 SO 4 , HCl, etc. each time it is regenerated, the amount of attached crud is often less than 500 mg/-RasFe. However, in anion exchange resin,
Adhering crud is difficult to remove with regenerant (caustic soda) and gradually accumulates to 1000-1500mg/
−RasFe may be reached in some cases. The form of the attached cladding is said to differ depending on the cation exchange resin and anion exchange resin, but the details are unknown. In boiling water nuclear power plants, the proportion of α-Fe 2 O 3 is large, and most of the crud is removed by cation exchange resin, and the amount of crud deposited by the cation exchange resin is 10,000 to 30,000 mg/-RasFe.
In some cases, it can reach . Although the proportion of crud adhering to anion exchange resin is extremely small, it gradually accumulates as in the case of thermal power plants. As the amount of crud adhesion increases as described above, the leakage of crud into the treated water also increases constantly. Even if backwashing or air scrubbing is performed frequently, only a small percentage of these deposited crud can be removed. Currently, at thermal power plants, when the amount of crud deposits exceeds 500 mg/-RasFe, iron removal regeneration treatment is performed using chemicals (iron removal regeneration agents), and substances mainly composed of sulfur oxides, such as hydrosulfite, Na 2 SO 3 , NaHSO 3 or the like is brought into contact with an ion exchange resin to reduce the adhering crud and remove it as soluble iron. The conventional general iron removal regeneration treatment process is as follows. (1) Otion exchange resin for resin ion type adjustment,
NaCl is added to the anion exchange resin in the same column to form Na-type and Cl-type, respectively. (2) A solid reducing agent is introduced through the manhole and the reduction process is carried out for several hours. At this time, the pH is strictly adjusted using caustic soda, H 2 SO 4 , or HCl.
This is to prevent a large amount of sulfur dioxide gas from being generated if the method goes to the acidic side, and also to prevent the iron removal effect from becoming quite small if the method goes to the alkaline side. After the ion exchange resin and the reducing agent are brought into contact for several hours, extrusion and washing are performed. In this step, the crud is eluted from the resin into the liquid as soluble iron and removed. (3) Backwash the mixed resin and separate the cation exchange resin.
Anion exchange resins are regenerated with H 2 SO 4 and HCl at two to three times the normal regeneration level, respectively. However, this iron removal regeneration method has the following drawbacks. (a) Reducing agents mainly composed of sulfur oxides are unstable and cannot be stored as a solution and are handled in solid form, which requires opening and closing of the manholes in the regeneration tower, resulting in poor workability. In addition, a large amount of sulfur dioxide gas is generated especially during dissolution or pH adjustment, which poses a considerable problem during work. (b) If the cation exchange resin and anion exchange resin are treated at the same time, the iron ions peeled off and reduced from the anion exchange resin in step (2) above will undergo ion exchange with the cation exchange resin, and will be subjected to the reduction treatment instead. The amount of iron in the cation exchange resin increases compared to before, and a large amount of inorganic acid is required to remove it, and the iron removal effect becomes smaller. (c) Because the NaCl treatment is carried out to specifically convert Na and Cl types, Na
A large amount of type and Cl type remains, and when an ammonia cycle is performed in subsequent water sampling, a large amount of
Na and Cl leaks occur. To avoid this, H
- After operating on the -OH cycle and seeing a decrease in Na type and Cl type, the system was shifted to the ammonia cycle. In other words, subsequent operation is severely restricted by the iron removal regeneration process. In boiling water nuclear power plants, iron removal regeneration agents containing reducing agents, which are used in thermal power plants, are not used for treatment. This is because ions such as Na, K, Cl, and SO 4 contained in the iron removal regenerating agent form salt types such as Na type and Cl type, so a large amount of regenerating agent is required to regenerate the salt type, resulting in a large amount of recycled waste liquid. This is because it is difficult to achieve treated water quality that is stricter than that at thermal power plants due to the amount of Cl leaking. Currently, cladding removal by ultrasonication is being experimentally performed, but its effectiveness is small, and further long-term research is required before it can be put to practical use. The present inventors conducted intensive research on an effective iron removal regenerating agent that eliminates the above drawbacks, mainly targeting ion exchange resins used in actual condensate desalination equipment at thermal power plants.As a result, oxalic acid, It has been discovered that iron removal regeneration can be effectively achieved by using a reducing agent and an inorganic acid. In other words, (1) Oxalic acid alone has no effect on cation exchange resins.
An iron removal rate of 30 to 40% can be obtained, but the iron removal rate is small and less than 10% for anion exchange resins. (2) A mixed solution of oxalic acid and inorganic acid is more effective than oxalic acid alone, showing an iron removal rate of 40 to 50% compared to cation exchange resin. However, like (1), it has little effect on anion exchange resins. (3) After treatment with oxalic acid or a mixture of oxalic acid and an inorganic acid, the cation exchange resin is treated with 70 to 80% H 2 SO 4 by passing with an inorganic acid.
More than 90% can be removed with HCl and HNO 3 . However, similar to (1) and (2), the effect on anion exchange resins is small. The reason why the iron removal effect of the anion exchange resin is insufficient is that the cation exchange resin and the anion exchange resin have considerably different forms of the cruds attached to them. The present inventors conducted further experiments to find an anion exchange resin that has an iron removal effect, and obtained the following results. (4) Using L-ascorbic acid or erythorbic acid as a reducing agent, the anion exchange resin is treated with a mixture of this reducing agent, oxalic acid, and an inorganic acid for 10 hours to several days, and then passed through the inorganic acid. The iron removal rate is over 90%. (5) Using even stronger reducing agents Na 2 SO 3 and NaHSO 3 and treating with a mixture of these reducing agents and oxalic acid or a mixture of these and an inorganic acid for several hours, and then passing the inorganic acid through. , the iron removal rate of anion exchange resin is over 90%. (6) Cation exchange resins can also be treated with a mixture of oxalic acid and a reducing agent or a mixture of oxalic acid, a reducing agent, and an inorganic acid, and then passed through with an inorganic acid to improve the iron removal rate. Even if the acid is H 2 SO 4
It will be 80-90%. (7) In the above treatment, the effect remains the same even if oxalate is used instead of oxalic acid and L-ascorbate or erythorbate is used as the reducing agent. The present invention was completed based on the above basic findings. That is, in the present invention, a mixture of at least one of oxalic acid and oxalate and a reducing agent, or a mixture of at least one of oxalic acid and oxalate, a reducing agent, and an inorganic acid is used for several tens of minutes to several days. After the treatment, the adhering crud is removed by passing an inorganic acid through the treatment. In contrast to the conventional method, in which the soluble crud is removed at once by the action of a reducing agent, the present invention converts the crud into a compound with low solubility, such as ferrous oxalate, and then removes the crud with an inorganic acid. It dissolves and removes compounds. When the ion exchange resin of the condensate desalination apparatus is subjected to iron removal regeneration treatment using the present invention, it is carried out as follows. If the resin to be treated is a cation exchange resin,
It is preferable to use a reducing agent that is not in a salt form, for example, an acid form such as L-ascorbic acid or erythorbic acid, so that it does not become a salt form during the iron removal regeneration process. After treatment with a mixed solution of acid and H 2 SO 4 (H 2 SO 4 is preferred as the inorganic acid when operating an ammonia cycle) for more than ten hours to several days, H 2 SO 4 is passed through. In this way, the cation exchange resin is regenerated to remove iron without turning into salt form at all. On the other hand, when treating an anion exchange resin, it is impossible to prevent it from turning into a salt form, so it is limited to at least one of oxalic acid and oxalate, an inorganic acid, and the above acid form as a reducing agent. Salt forms such as Na 2 SO 3 , NaHSO 3 , L-ascorbate, and erythorbate may also be used. When Na 2 SO 3 or NaHSO 3 is used, an iron removal rate of 90% or more can be obtained by controlling the pH of the mixed solution to 2 or less, treating it for several tens of minutes to several hours, and then passing it through with an inorganic acid. However, sulfur dioxide gas is generated during processing, so care must be taken when handling it. In addition, in the conventional method, Na 2 SO 3 , NaHSO 3
Even when using iron, the iron removal rate is low, less than 50%. When using L-ascorbic acid or its salts, or erythorbic acid or its salts, their reducing power is weak, so
It is preferable to perform the treatment with the mixed solution for several hours to several days. The mixed solution of both cation exchange resin and anion exchange resin contains at least one of oxalic acid and oxalate.
0.1-8% (1-160g/-R), reducing agent 0.1-8%
10% (1-200g/-R), 0.5-15% inorganic acid
The mixture is mixed and dissolved so that the reducing agent is mixed and dissolved, and the mixture is stirred and left for an appropriate time depending on the type of reducing agent as described above. In this mixture, depending on the inorganic acid used, the cladding is e.g.
In the case of H 2 SO 4 , some of it dissolves in the form of ferrous sulfate, etc., but the dissolved amount is only about 30% of the total, and the rest is compounds with low solubility in the form of ferrous oxalate, etc. It adheres to the resin layer as a. Next, drain this mixed solution, adjust the concentration of inorganic acid to 1-10%, and increase the concentration of 200-400%.
By passing 3 g/-RasCaCO, the compounds with low solubility become ferrous sulfate, ferric sulfate, etc. and are completely removed. At this time, the anion exchange resin changes into SO 4 type, Cl type, etc. depending on the inorganic acid used. In condensate desalination equipment, it is necessary to reduce leakage of not only Na but also anions as much as possible during operation of an ammonia cycle, etc., and anion exchange resins are more effective than Cl type.
H 2 SO 4 is used as the inorganic acid because the SO 4 type has less leakage during the ammonia cycle and the SO 4 type is much easier to regenerate with caustic soda than the Cl type. It is convenient. In the present invention, when the ion exchange resin is a mixed resin, it is preferable to use H 2 SO 4 as the inorganic acid and conduct the drug passage as described below. The mixed resin is backwashed and separated, and each resin is transferred to a separate regeneration tower. Each resin is treated separately with the mixture. Next, H 2 SO 4 is passed through the cation exchange resin to regenerate it into H-type and to remove the low-solubility compound. The regenerated waste liquid after passing through the solution is passed through an anion exchange resin to convert it into SO 4 type, and at the same time, remove the low-solubility compounds. Next, examples of the present invention will be described. Example 1 Iron removal regeneration treatment was performed on an anion exchange resin currently in use in an actual condensate desalination device. The amount of iron deposited on anion exchange resin before treatment is
650mg/-R (OH type). The types of mixed liquids for treatment are as shown in Table 1. In all treatment methods, the ratio of each single chemical as a component of each mixed liquid to resin is 100g to 1 resin, and The total volume was set to 2.
In addition, in either treatment method, the resin is
H 2 SO 4 was added to make it into SO 4 form and then other chemicals were added.
【表】
処理の工程については、上記各混合物試料を5
分間撹拌・混合後、5時間静置し、次いで濃度8
%のH2SO4をSV3、再生レベル(RL)を300g/
−RasCaCO3として通薬し再生した。処理結果
は第2表のとおりである。[Table] Regarding the processing steps, each of the above mixture samples was
After stirring and mixing for 5 minutes, let it stand for 5 hours, and then
% H2SO4 to SV3, regeneration level ( RL) to 300g/
− It was regenerated by passing the drug as RasCaCO 3 . The processing results are shown in Table 2.
【表】
実施例 2
実施例1と同一の樹脂について還元剤、無機酸
を変えて同様の実験を行つた。
各混合液の成分は第3表のとおりであり、実施
例1と比べた実験条件の相異点は、撹拌・混合工
程を省略したこと、その代りに静置時間を24時間
と長くしたこと、再生剤として第3表に併記した
ようにH2SO4以外のものを使用したことである。[Table] Example 2 A similar experiment was carried out using the same resin as in Example 1 by changing the reducing agent and inorganic acid. The components of each mixture are shown in Table 3, and the differences in the experimental conditions compared to Example 1 are that the stirring and mixing steps were omitted, and instead the standing time was extended to 24 hours. As shown in Table 3, a substance other than H 2 SO 4 was used as a regenerating agent.
【表】【table】
【表】
なお、上記各再生剤の濃度と再生レベルについ
ても実施例1と同一である。処理結果を第4表に
示す。[Table] Note that the concentrations and regeneration levels of each of the above-mentioned regenerants are also the same as in Example 1. The processing results are shown in Table 4.
【表】
実施例 3
復水脱塩装置の実機で使用中のカチオン交換樹
脂について実施例2と同様の実験を行つた。
処理前におけるカチオン樹脂の鉄付着量は410
mg/−RasFeである。処理用混合液の種類は第
5表のとおりで、樹脂とこの混合液との混合物試
料の調製要領は実施例1と同様であり、処理工程
は実施例2と同じく24時間静置とその後のH2SO4
による再生処理からなる。実験結果は第6表のと
おりである。[Table] Example 3 An experiment similar to Example 2 was conducted on a cation exchange resin currently in use in an actual condensate desalination device. The amount of iron attached to the cationic resin before treatment is 410
mg/−RasFe. The types of the mixed liquid for treatment are as shown in Table 5. The procedure for preparing a mixture sample of resin and this mixed liquid is the same as in Example 1, and the treatment process is the same as in Example 2, including standing for 24 hours and subsequent treatment. H 2 SO 4
It consists of playback processing by The experimental results are shown in Table 6.
【表】【table】
【表】
実施例 4
実施例2の処理法(11)及び実施例3の処理法
(22)で得られた除鉄回生処理後の樹脂を等量で
混合してアニオン交換樹脂とカチオン交換樹脂と
の混合樹脂となし、これを用いて実機による復水
をイオン交換処理したところ処理水水質は第7表
のとおり導電率、全鉄ともに低下し、樹脂の除鉄
回生処理の効果が確認された。つづいてアンモニ
アサイクル通水を行つたが処理水のNa、Clリー
クはいずれも0.3ppb以下を示した。[Table] Example 4 An anion exchange resin and a cation exchange resin were prepared by mixing equal amounts of the resins after the iron removal regeneration treatment obtained by the treatment method (11) of Example 2 and the treatment method (22) of Example 3. When condensate was ion-exchanged using this mixed resin in an actual machine, the quality of the treated water decreased in both electrical conductivity and total iron as shown in Table 7, confirming the effectiveness of the iron removal regeneration treatment of the resin. Ta. Next, water was passed through an ammonia cycle, but the Na and Cl leaks in the treated water were both below 0.3 ppb.
【表】
以上述べた如く本発明は、火力発電所の復水脱
塩装置にとつて大きな効果を有するものであり、
また、原子力発電所の復水脱塩装置についてもカ
チオン交換樹脂を塩型にすることなくクラツドを
除去できると共に、その後の再生工程及び採水工
程を円滑に行うことができるなど、大きいメリツ
トを有している。更に本発明はクラツドの付着し
た純水装置、粉末状イオン交換樹脂、その他クラ
ツドの付着した充てん剤の洗浄にも有効に適用で
きるものであり、産業技術に貢献するところ大で
ある。[Table] As described above, the present invention has great effects on condensate desalination equipment for thermal power plants.
In addition, it has great advantages for condensate desalination equipment at nuclear power plants, such as being able to remove crud without turning the cation exchange resin into salt form, and making it possible to perform the subsequent regeneration process and water sampling process smoothly. are doing. Furthermore, the present invention can be effectively applied to clean water purifiers with cruds, powdered ion exchange resins, and other fillers with cruds, making a significant contribution to industrial technology.
Claims (1)
酸、シユウ酸塩の少なくとも一方と還元剤の混合
液、又はシユウ酸、シユウ酸塩の少なくとも一方
と還元剤と無機酸の混合液で処理した後、無機酸
を通薬することを特徴とするイオン交換樹脂の除
鉄回生方法。 2 前記クラツドの付着したイオン交換樹脂がカ
チオン交換樹脂である場合に、前記還元剤として
塩の形でないものを使用する特許請求の範囲第1
項記載の方法。 3 前記クラツドの付着したイオン交換樹脂がカ
チオン交換樹脂とアニオン交換樹脂との混合樹脂
である場合に、該混合樹脂を個別の塔に分離した
後、これら各イオン交換樹脂について除鉄回生操
作を行う特許請求の範囲第1項又第2項記載の方
法。 4 前記カチオン交換樹脂についての除鉄回生操
作において通薬した後の無機酸排出液を、アニオ
ン交換樹脂へ通液する特許請求の範囲第3項記載
の方法。[Scope of Claims] 1. The ion exchange resin to which the cladding is attached is treated with a mixed solution of at least one of oxalic acid and oxalate and a reducing agent, or a mixed solution of at least one of oxalic acid and oxalate, a reducing agent, and an inorganic acid. A method for regenerating iron removal from an ion exchange resin, which comprises treating the resin with an inorganic acid and then passing it through an inorganic acid. 2. When the ion exchange resin to which the cladding is attached is a cation exchange resin, claim 1 in which the reducing agent is not in the form of a salt.
The method described in section. 3. When the ion exchange resin to which the crud is attached is a mixed resin of a cation exchange resin and an anion exchange resin, after separating the mixed resin into individual columns, iron removal regeneration operation is performed for each of these ion exchange resins. A method according to claim 1 or 2. 4. The method according to claim 3, wherein the inorganic acid discharged liquid after being passed through the anion exchange resin in the iron removal regeneration operation for the cation exchange resin is passed through the anion exchange resin.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP57144799A JPS5936550A (en) | 1982-08-23 | 1982-08-23 | Regeneration of ion exchange resin by removing iron |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP57144799A JPS5936550A (en) | 1982-08-23 | 1982-08-23 | Regeneration of ion exchange resin by removing iron |
Publications (2)
Publication Number | Publication Date |
---|---|
JPS5936550A JPS5936550A (en) | 1984-02-28 |
JPS6255898B2 true JPS6255898B2 (en) | 1987-11-21 |
Family
ID=15370724
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP57144799A Granted JPS5936550A (en) | 1982-08-23 | 1982-08-23 | Regeneration of ion exchange resin by removing iron |
Country Status (1)
Country | Link |
---|---|
JP (1) | JPS5936550A (en) |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS6238247A (en) * | 1985-08-12 | 1987-02-19 | Hitachi Ltd | Method for regenerating ion exchange resin |
-
1982
- 1982-08-23 JP JP57144799A patent/JPS5936550A/en active Granted
Also Published As
Publication number | Publication date |
---|---|
JPS5936550A (en) | 1984-02-28 |
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