JPS6232995B2 - - Google Patents
Info
- Publication number
- JPS6232995B2 JPS6232995B2 JP53105956A JP10595678A JPS6232995B2 JP S6232995 B2 JPS6232995 B2 JP S6232995B2 JP 53105956 A JP53105956 A JP 53105956A JP 10595678 A JP10595678 A JP 10595678A JP S6232995 B2 JPS6232995 B2 JP S6232995B2
- Authority
- JP
- Japan
- Prior art keywords
- waste liquid
- dithionate
- flue gas
- ions
- gas desulfurization
- 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
- 229940075933 dithionate Drugs 0.000 claims description 39
- 150000002500 ions Chemical class 0.000 claims description 39
- 239000007788 liquid Substances 0.000 claims description 34
- 239000002699 waste material Substances 0.000 claims description 31
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 claims description 28
- 239000003546 flue gas Substances 0.000 claims description 28
- 238000006477 desulfuration reaction Methods 0.000 claims description 23
- 230000023556 desulfurization Effects 0.000 claims description 23
- 238000000034 method Methods 0.000 claims description 23
- 229910052782 aluminium Inorganic materials 0.000 claims description 14
- -1 aluminum ions Chemical class 0.000 claims description 14
- 229910052602 gypsum Inorganic materials 0.000 claims description 14
- 239000010440 gypsum Substances 0.000 claims description 14
- 239000003795 chemical substances by application Substances 0.000 claims description 13
- 239000002244 precipitate Substances 0.000 claims description 8
- 239000003513 alkali Substances 0.000 claims description 5
- AXCZMVOFGPJBDE-UHFFFAOYSA-L calcium dihydroxide Chemical compound [OH-].[OH-].[Ca+2] AXCZMVOFGPJBDE-UHFFFAOYSA-L 0.000 description 14
- 239000000920 calcium hydroxide Substances 0.000 description 14
- 229910001861 calcium hydroxide Inorganic materials 0.000 description 14
- VEXZGXHMUGYJMC-UHFFFAOYSA-M Chloride anion Chemical compound [Cl-] VEXZGXHMUGYJMC-UHFFFAOYSA-M 0.000 description 11
- 239000002253 acid Substances 0.000 description 9
- VTYYLEPIZMXCLO-UHFFFAOYSA-L Calcium carbonate Chemical compound [Ca+2].[O-]C([O-])=O VTYYLEPIZMXCLO-UHFFFAOYSA-L 0.000 description 8
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 8
- CDBYLPFSWZWCQE-UHFFFAOYSA-L Sodium Carbonate Chemical compound [Na+].[Na+].[O-]C([O-])=O CDBYLPFSWZWCQE-UHFFFAOYSA-L 0.000 description 8
- 238000001556 precipitation Methods 0.000 description 8
- 239000010802 sludge Substances 0.000 description 8
- 238000005345 coagulation Methods 0.000 description 7
- 230000015271 coagulation Effects 0.000 description 7
- 229910018072 Al 2 O 3 Inorganic materials 0.000 description 6
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 6
- 230000003647 oxidation Effects 0.000 description 6
- 238000007254 oxidation reaction Methods 0.000 description 6
- 238000000926 separation method Methods 0.000 description 6
- 238000005979 thermal decomposition reaction Methods 0.000 description 6
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 5
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 4
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 4
- WNROFYMDJYEPJX-UHFFFAOYSA-K aluminium hydroxide Chemical compound [OH-].[OH-].[OH-].[Al+3] WNROFYMDJYEPJX-UHFFFAOYSA-K 0.000 description 4
- 229910000019 calcium carbonate Inorganic materials 0.000 description 4
- 229910000029 sodium carbonate Inorganic materials 0.000 description 4
- KWYUFKZDYYNOTN-UHFFFAOYSA-M Potassium hydroxide Chemical compound [OH-].[K+] KWYUFKZDYYNOTN-UHFFFAOYSA-M 0.000 description 3
- 150000007513 acids Chemical class 0.000 description 3
- 239000000654 additive Substances 0.000 description 3
- 150000004645 aluminates Chemical class 0.000 description 3
- DIZPMCHEQGEION-UHFFFAOYSA-H aluminium sulfate (anhydrous) Chemical compound [Al+3].[Al+3].[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O DIZPMCHEQGEION-UHFFFAOYSA-H 0.000 description 3
- 239000000428 dust Substances 0.000 description 3
- 239000007789 gas Substances 0.000 description 3
- 229910001385 heavy metal Inorganic materials 0.000 description 3
- 230000002452 interceptive effect Effects 0.000 description 3
- 238000010979 pH adjustment Methods 0.000 description 3
- 238000011084 recovery Methods 0.000 description 3
- 229910052815 sulfur oxide Inorganic materials 0.000 description 3
- 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 description 2
- 235000008733 Citrus aurantifolia Nutrition 0.000 description 2
- MHAJPDPJQMAIIY-UHFFFAOYSA-N Hydrogen peroxide Chemical compound OO MHAJPDPJQMAIIY-UHFFFAOYSA-N 0.000 description 2
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 2
- 235000011941 Tilia x europaea Nutrition 0.000 description 2
- 238000010521 absorption reaction Methods 0.000 description 2
- 229940037003 alum Drugs 0.000 description 2
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 2
- 239000003245 coal Substances 0.000 description 2
- 238000002485 combustion reaction Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 239000010881 fly ash Substances 0.000 description 2
- 239000003456 ion exchange resin Substances 0.000 description 2
- 229920003303 ion-exchange polymer Polymers 0.000 description 2
- 229910052742 iron Inorganic materials 0.000 description 2
- 239000004571 lime Substances 0.000 description 2
- WPBNNNQJVZRUHP-UHFFFAOYSA-L manganese(2+);methyl n-[[2-(methoxycarbonylcarbamothioylamino)phenyl]carbamothioyl]carbamate;n-[2-(sulfidocarbothioylamino)ethyl]carbamodithioate Chemical compound [Mn+2].[S-]C(=S)NCCNC([S-])=S.COC(=O)NC(=S)NC1=CC=CC=C1NC(=S)NC(=O)OC WPBNNNQJVZRUHP-UHFFFAOYSA-L 0.000 description 2
- 229910052759 nickel Inorganic materials 0.000 description 2
- 239000002002 slurry Substances 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- XTQHKBHJIVJGKJ-UHFFFAOYSA-N sulfur monoxide Chemical class S=O XTQHKBHJIVJGKJ-UHFFFAOYSA-N 0.000 description 2
- CBENFWSGALASAD-UHFFFAOYSA-N Ozone Chemical compound [O-][O+]=O CBENFWSGALASAD-UHFFFAOYSA-N 0.000 description 1
- QAOWNCQODCNURD-UHFFFAOYSA-L Sulfate Chemical compound [O-]S([O-])(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-L 0.000 description 1
- ANBBXQWFNXMHLD-UHFFFAOYSA-N aluminum;sodium;oxygen(2-) Chemical compound [O-2].[O-2].[Na+].[Al+3] ANBBXQWFNXMHLD-UHFFFAOYSA-N 0.000 description 1
- 239000002956 ash Substances 0.000 description 1
- 239000003153 chemical reaction reagent Substances 0.000 description 1
- 238000000975 co-precipitation Methods 0.000 description 1
- 239000000701 coagulant Substances 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 238000000354 decomposition reaction Methods 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 238000005265 energy consumption Methods 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 238000001914 filtration Methods 0.000 description 1
- 239000008394 flocculating agent Substances 0.000 description 1
- 239000010842 industrial wastewater Substances 0.000 description 1
- 238000009434 installation Methods 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 239000007800 oxidant agent Substances 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 150000003839 salts Chemical class 0.000 description 1
- 238000004062 sedimentation Methods 0.000 description 1
- 239000000779 smoke Substances 0.000 description 1
- 229910001388 sodium aluminate Inorganic materials 0.000 description 1
- CSMWJXBSXGUPGY-UHFFFAOYSA-L sodium dithionate Chemical compound [Na+].[Na+].[O-]S(=O)(=O)S([O-])(=O)=O CSMWJXBSXGUPGY-UHFFFAOYSA-L 0.000 description 1
- 229940075931 sodium dithionate Drugs 0.000 description 1
- LSNNMFCWUKXFEE-UHFFFAOYSA-L sulfite Chemical compound [O-]S([O-])=O LSNNMFCWUKXFEE-UHFFFAOYSA-L 0.000 description 1
- 150000003464 sulfur compounds Chemical class 0.000 description 1
- 239000002351 wastewater Substances 0.000 description 1
Landscapes
- Treating Waste Gases (AREA)
- Separation Of Suspended Particles By Flocculating Agents (AREA)
- Removal Of Specific Substances (AREA)
Description
【発明の詳細な説明】
本発明は石灰石―石こう法湿式排煙脱硫装置か
ら排出される廃液中のジチオン酸イオンを簡単な
処理システムで二次公害を引き起こすことなくほ
ぼ完全に分離することを可能ならしめる湿式排煙
脱硫廃液処理方法に関する。[Detailed Description of the Invention] The present invention makes it possible to almost completely separate dithionate ions in the waste liquid discharged from a limestone-gypsum wet flue gas desulfurization equipment using a simple treatment system without causing secondary pollution. This invention relates to a wet flue gas desulfurization waste liquid treatment method.
石油および石炭燃焼装置よりの硫黄酸化物
（SOX）含有の排ガスを処理した石灰石―石こう
法湿式排煙脱硫装置から排出される廃液は上記排
ガスの除じんおよびSO2吸収のために使用された
液を、さらに酸化塔、石こう分離装置を通過させ
たものであり、この廃液にはSSおよび鉄、マン
ガン、ニツケル、アルミニウム等の重金属類のほ
かに、亜硫酸イオンを主成分とする還元性物質の
酸化により生成した硫酸イオンや上記過程におい
て生成したいくつかの低級硫黄化合物であるポリ
チオン酸類が含まれている。このポリチオン酸類
の中でも、難酸化性のジチオン酸イオン
（S2O6 2-）がCOD成分の主体をなしている。従つ
て、このジチオン酸イオンを分離すれば、COD
は確実に低下することになる。しかしながら、こ
のジチオン酸イオンは非常に安定な物質で過酸化
水素やオゾンなどの強力な酸化剤を用いての酸化
処理や通常の凝集沈殿処理では除去することがほ
とんど不可能であるので、従来は加熱分解法によ
つてのみ除去されているが、この加熱分解法にお
いても上記廃液を直接加熱するのはエネルギー消
費の面で不利であるので、あらかじめジチオン酸
イオンをイオン交換樹脂で分離した後、減容され
た再生廃液を加熱するシステムをとつている。し
かしながら、この加熱分解法はなお多量の熱量を
必要とするだけでなく、高濃度の硫酸等の酸を加
えて加熱するので加熱分解装置には耐食性材料を
用いなければならず、設備費を高くする要因とな
つている。しかもジチオン酸イオンの分解は70％
にすぎない。 The waste liquid discharged from the limestone-gypsum wet flue gas desulfurization equipment that treated flue gas containing sulfur oxides ( SOx ) from oil and coal combustion equipment was used to remove dust from the flue gas and absorb SO2 . The liquid is further passed through an oxidation tower and a gypsum separator, and this waste liquid contains not only SS and heavy metals such as iron, manganese, nickel, and aluminum, but also reducing substances mainly composed of sulfite ions. It contains sulfate ions produced by oxidation and polythionic acids, which are some lower sulfur compounds produced in the above process. Among these polythionic acids, the oxidation-resistant dithionate ion (S 2 O 6 2- ) is the main component of COD. Therefore, if this dithionate ion is separated, COD
will definitely decline. However, this dithionate ion is a very stable substance and it is almost impossible to remove it by oxidation treatment using strong oxidizing agents such as hydrogen peroxide or ozone or by ordinary coagulation precipitation treatment. Although it is only removed by thermal decomposition, it is disadvantageous in terms of energy consumption to directly heat the waste liquid even in this thermal decomposition method, so after separating the dithionate ions with an ion exchange resin, A system is in place to heat the recycled waste liquid whose volume has been reduced. However, this thermal decomposition method not only still requires a large amount of heat, but also requires the addition of highly concentrated acids such as sulfuric acid, which requires the use of corrosion-resistant materials for the thermal decomposition equipment, resulting in high equipment costs. This is a contributing factor. Moreover, the decomposition of dithionate ion is 70%.
It's nothing more than that.
本発明は上記の従来法の欠点を解決し、石灰石
―石こう法湿式排煙装置から排出される廃液中の
ジチオン酸イオンを簡単な処理システムで二次公
害を引き起こすことなく、ほぼ完全に分離するこ
とを可能ならしめる湿式排煙脱硫廃液処理方法を
提供するもので、その要旨とするところは、石灰
石―石こう法排煙脱硫装置から排出されるジチオ
ン酸イオンを含む廃液の処理方法において、該廃
液をアルカリ処理したのち過し、該過された
廃液にアルミニウムイオンを含む無機系凝集剤を
加え、さらにアルカリ剤でPHを10以上にしてジチ
オン酸イオンを凝集沈殿させることを特徴とする
湿式排煙脱硫廃液処理方法、にある。 The present invention solves the above-mentioned drawbacks of the conventional method, and almost completely separates dithionate ions in the waste liquid discharged from a limestone-gypsum wet smoke evacuation system using a simple treatment system without causing secondary pollution. The purpose of the present invention is to provide a wet flue gas desulfurization waste liquid treatment method that makes it possible to A wet flue gas flue gas system characterized by treating the waste liquid with an alkali, filtering it, adding an inorganic flocculant containing aluminum ions to the filtered waste liquid, and further adjusting the pH to 10 or more with an alkaline agent to coagulate and precipitate dithionate ions. Desulfurization waste liquid treatment method.
次に、本発明を図面によつて説明する。 Next, the present invention will be explained with reference to the drawings.
図面は石灰石―石こう法湿式排煙脱硫工程を含
めての本発明の一実施例のフローシートである。 The drawing is a flow sheet of an embodiment of the present invention including a limestone-gypsum wet flue gas desulfurization process.
図において、は石灰石―石こう法湿式排煙脱
硫工程、は排煙脱硫廃液処理工程である。排煙
脱硫工程はボイラーからの硫黄酸化物含有の排
ガス１６の除じん工程１、SO2吸収工程２、酸化
工程３および石こう分離工程４よりなり、１０は
石灰スラリー、１７は脱硫排ガスである。排煙脱
硫廃液処理工程は上記湿式排煙脱硫工程から
の廃液のアルカリ剤、たとえば水酸化カルシウム
１１添加による凝集沈殿処理工程５、アルミニウ
ムイオンを含む無機系凝集剤、たとえばポリ塩化
アルミニウム１２とアルカリ剤、たとえば水酸化
カルシウム１３との添加によるSO6 2-分離除去工
程６、炭酸ナトリウム１４の添加による炭酸カル
シウム回収工程７、酸１５添加によるPH調節工程
８および過工程９よりなり、１８はスラツジ、
１９はSO6 2-を含むスラツジ、２０は回収
CaCO3、２１は水酸化アルミニウム、２２は処
理水である。 In the figure, indicates the limestone-gypsum wet flue gas desulfurization process, and indicates the flue gas desulfurization waste liquid treatment process. The flue gas desulfurization step consists of a dust removal step 1, an SO 2 absorption step 2, an oxidation step 3, and a gypsum separation step 4 for the flue gas 16 containing sulfur oxides from the boiler, where 10 is lime slurry and 17 is the desulfurized flue gas. The flue gas desulfurization waste liquid treatment step includes a coagulation and precipitation treatment step 5 by adding an alkaline agent, such as calcium hydroxide 11, to the waste liquid from the wet flue gas desulfurization process, and an inorganic flocculant containing aluminum ions, such as polyaluminum chloride 12, and an alkaline agent. , for example, includes an SO 6 2- separation and removal step 6 by adding calcium hydroxide 13, a calcium carbonate recovery step 7 by adding sodium carbonate 14, a PH adjustment step 8 by adding acid 15, and a passing step 9, 18 is sludge,
19 is sludge containing SO 6 2- , 20 is recovered
CaCO 3 , 21 is aluminum hydroxide, and 22 is treated water.
すなわち、排煙脱硫廃液処理工程の最初の工
程である凝集沈殿処理工程５では、石灰石−石こ
う法湿式排煙脱硫工程の最終工程からの廃液に
アルカリ剤１１を添加し、上述したように、該廃
液に含まれるSS、鉄、マンガン、ニツケル、ア
ルミニウム等の重金属類を凝集沈殿させ、これら
をスラツジ１８として分離する。この段階ではな
おジチオン酸イオンが約千数百ppm含まれてい
る。上記アルカリ剤１１としては水酸化カルシウ
ミ、水酸化ナトリウム、炭酸ナトリウム等が用い
られるが、水酸化カルシウムが好適である。PHと
してはアルカリ性、好ましくは10以上に調整す
る。 That is, in the coagulation-sedimentation treatment step 5, which is the first step in the flue gas desulfurization waste liquid treatment step, the alkaline agent 11 is added to the waste liquid from the final step of the limestone-gypsum wet flue gas desulfurization step, and as described above, the Heavy metals such as SS, iron, manganese, nickel, and aluminum contained in the waste liquid are coagulated and precipitated, and these are separated as sludge 18. At this stage, it still contains about 1,000 and several hundred ppm of dithionate ions. As the alkali agent 11, calcium hydroxide, sodium hydroxide, sodium carbonate, etc. are used, but calcium hydroxide is preferred. The pH is adjusted to alkaline, preferably 10 or higher.
次に、ジチオン酸イオン分離除去工程６では、
まず凝集沈殿処理工程５からの廃液にポリ塩化ア
ルミニウム１２を添加し、さらに水酸化カルシウ
ム１３を添加してPHを10以上にすることによつ
て、ジチオン酸イオン凝集、沈殿させる。このよ
うに、アルミニウムイオンを含む無機系凝集剤、
たとえばポリ塩化アルミニウム１２に過剰のアル
カリ剤、たとえば水酸化カルシウム１３を添加す
ることによつて、難溶性水和アルミン酸塩を生成
させ、この難溶性水和アルミン酸塩にジチオン酸
イオンを吸着させて共沈の形で凝集沈殿させ、ス
ラツジ１９として廃液から分離除去されるのであ
る。上記アルミニウムイオンを含む無機系凝集剤
１２としてはポリ塩化アルミニウム、アルミン酸
ナトリウム、硫酸アルミニウム、ミヨウバン等が
用いられるが、ポリ塩化アルミニウムが最も好適
である。また、石炭燃焼装置から排出されるフラ
イアツシユは微小な灰の粒子でAl2O3を通常20％
前後含有するので、これを酸、たとえば塩酸で処
理して得られるアルミニウムイオン溶液を上記凝
集剤として使用することができる。フライアツシ
ユはきわめて安価であるので、その使用はコスト
的に著しく有利となる。一方、硫酸アルミニウ
ム、ミヨウバンはジチオン酸イオンの上記凝集沈
殿を妨害するSO4 2-を含むので好ましくないが、
このSO4 2-の妨害作用はアルミニウムイオン量を
増すことによつて防ぐことができる。これらアル
ミニウムイオンを含む無機系凝集剤１２の添加量
はジチオン酸イオン濃度に比例し、ジチオン酸イ
オン濃度１に対して理論値の２倍、すなわち
Al2O3として１の濃度を添加する。たとえば、ジ
チオン酸イオン1000ppmに対してはポリ塩化ア
ルミニウムはAl2O3として1000ppm添加する。こ
の添加量は上記SO4 2-の妨害作用を考慮した一般
的の場合であつて、理論値の２倍に相当するもの
である。ただし、SO4 2-の妨害作用を考慮する必
要のない場合には理論値に相当する添加量でよ
い。また、上記アルカリ剤１３としては水酸化カ
ルシウムが好適である。水酸化ナトリウム、水酸
化カリウム等は単独使用ではジチオン酸イオンを
沈殿させることはできないが、アルミニウムイオ
ンを含む無機系凝集剤と併用すればジチオン酸イ
オンを沈殿させることができる。これらアルカリ
剤１３の過剰添加によつてPHを10以上に保つ理由
は、実験の結果、PH＝10からジチオン酸イオンの
凝集沈殿による除去効果があらわれ、PH11〜12で
はほぼ90〜99％近い除去効果が確認されたためで
ある。 Next, in dithionate ion separation and removal step 6,
First, polyaluminum chloride 12 is added to the waste liquid from the coagulation-precipitation treatment step 5, and calcium hydroxide 13 is further added to adjust the pH to 10 or more, thereby causing dithionate ions to coagulate and precipitate. In this way, inorganic flocculants containing aluminum ions,
For example, by adding an excess of an alkaline agent such as calcium hydroxide 13 to polyaluminum chloride 12, a sparingly soluble hydrated aluminate is produced, and dithionate ions are adsorbed to the sparingly soluble hydrated aluminate. The sludge is coagulated and precipitated in the form of coprecipitation, and is separated and removed from the waste liquid as sludge 19. As the inorganic flocculant 12 containing aluminum ions, polyaluminum chloride, sodium aluminate, aluminum sulfate, alum, etc. are used, but polyaluminum chloride is most preferred. In addition, fly ash discharged from coal combustion equipment is a fine ash particle that usually contains 20% Al 2 O 3 .
Therefore, an aluminum ion solution obtained by treating this with an acid, for example, hydrochloric acid, can be used as the flocculant. Since fly ash is extremely inexpensive, its use is extremely cost-effective. On the other hand, aluminum sulfate and alum are not preferred because they contain SO 4 2- , which interferes with the above-mentioned coagulation and precipitation of dithionate ions.
This interfering effect of SO 4 2- can be prevented by increasing the amount of aluminum ions. The amount of the inorganic flocculant 12 containing aluminum ions added is proportional to the dithionate ion concentration, and is twice the theoretical value for a dithionate ion concentration of 1, i.e.
Add a concentration of 1 as Al 2 O 3 . For example, for 1000 ppm of dithionate ion, 1000 ppm of polyaluminum chloride is added as Al 2 O 3 . This addition amount is a general case taking into consideration the interfering effect of SO 4 2- mentioned above, and corresponds to twice the theoretical value. However, if there is no need to consider the interfering effect of SO 4 2- , the addition amount may be equivalent to the theoretical value. Moreover, calcium hydroxide is suitable as the alkali agent 13. Sodium hydroxide, potassium hydroxide, etc. cannot precipitate dithionate ions when used alone, but can precipitate dithionate ions when used in combination with an inorganic flocculant containing aluminum ions. The reason why the pH is kept above 10 by adding excess alkaline agent 13 is that as a result of experiments, the removal effect by coagulation and precipitation of dithionate ions appears from pH = 10, and at pH 11 to 12, the removal is nearly 90 to 99%. This is because its effectiveness has been confirmed.
このように、アルミニウムイオンを含む無機系
凝集剤１２と過剰のアルカリ剤１３の併用による
凝集沈殿によつて、通常の凝集沈殿処理では除去
することがほとんど不可能であつた上記廃液中の
COD成分の主体をなすジチオン酸イオンを千数
百ppmから10ppm以下にまで低下させることを
可能ならしめるものである。 In this way, the coagulation and precipitation caused by the combined use of the inorganic coagulant 12 containing aluminum ions and the excess alkaline agent 13 removes the waste liquid, which is almost impossible to remove by normal coagulation and precipitation treatment.
This makes it possible to reduce dithionate ions, which are the main component of COD, from several thousand ppm to less than 10 ppm.
さらに、炭酸カルシウム回収工程７ではジチオ
ン酸イオン分離除去工程６からの廃液に炭酸ナト
リウム１４を添加して沈殿生成するCaCO3２０
を回収し、PH調節工程８では酸（塩酸が好適）１
５を添加してPH７前後に調整し再生成する水酸化
アルミニウムをスラツジ２１として分離し、最後
に過工程９では液はそのまま無害な処理水２
２として放流することができる。 Furthermore, in the calcium carbonate recovery step 7, sodium carbonate 14 is added to the waste liquid from the dithionate ion separation and removal step 6 to precipitate CaCO 3 20.
is recovered, and in the PH adjustment step 8, an acid (hydrochloric acid is preferred) 1
5 is added to adjust the pH to around 7, and the regenerated aluminum hydroxide is separated as sludge 21.Finally, in a pass step 9, the liquid is converted into harmless treated water 2.
It can be released as 2.
本発明の効果は次の通りである。 The effects of the present invention are as follows.
(1) 廃液中のCOD成分の主体をなすジチオン酸
イオンをほぼ100％除去でき、放流される処理
水中のジチオン酸イオン濃度を10ppm以下と
することができる。(1) Almost 100% of dithionate ions, which are the main component of COD in wastewater, can be removed, and the concentration of dithionate ions in discharged treated water can be reduced to 10 ppm or less.
(2) 添加剤はアルカリ剤として水酸化カルシウ
ム、酸として塩酸、アルミニウムイオンを含む
無機系凝集剤としてポリ塩化アルミニウムが好
適であるので、これらを使用することによつて
二次公害を引きおこすことはない。従つて、PH
＝10以上で生成する難溶性水和アルミン酸塩と
ジチオン酸イオンとからなる沈殿を分離し、さ
らにPH＝７前後に調整した時に再生成する水酸
化アルミニウムを分離すれば過水は無害な処
理水として放流できる。(2) Calcium hydroxide as an alkaline agent, hydrochloric acid as an acid, and polyaluminum chloride as an inorganic flocculant containing aluminum ions are suitable additives, so the use of these additives will not cause secondary pollution. do not have. Therefore, PH
If you separate the precipitate consisting of poorly soluble hydrated aluminate and dithionate ion that forms at pH = 10 or higher, and then separate the aluminum hydroxide that regenerates when the pH is adjusted to around 7, perhydration can be treated as a harmless treatment. It can be released as water.
(3) 使用する添加剤は安く、従来の加熱分解法の
ように熱源を必要としない。(3) The additives used are cheap and do not require a heat source like traditional thermal decomposition methods.
(4) 従来のイオン交換樹脂塔や加熱分解装置等を
必要とせず、しかも非常に簡単な処理システム
であるので設備費は低廉でかつ設置面積は小さ
い。(4) Since it does not require conventional ion exchange resin towers or thermal decomposition equipment, and is a very simple treatment system, the equipment cost is low and the installation area is small.
(5) 運転管理が容易である。(5) Operation management is easy.
本発明は、以上のごとく、石灰石―石こう法湿
式排煙脱硫装置から排出される廃液中のCOD成
分の主体をなすジチオン酸イオンを簡単な処理シ
ステムで二次公害を引き起こすことなくほぼ完全
に分離することを可能ならしめる湿式排煙脱硫廃
液処理方法を提供するもので、産業廃水公害対策
上きわめて有用である。 As described above, the present invention can almost completely separate dithionate ions, which are the main component of COD components in the waste liquid discharged from limestone-gypsum wet flue gas desulfurization equipment, without causing secondary pollution, using a simple treatment system. The present invention provides a wet flue gas desulfurization waste liquid treatment method that makes it possible to do this, and is extremely useful as a countermeasure against industrial wastewater pollution.
次に本発明を実施例によつてさらに具体的に説
明する。 Next, the present invention will be explained in more detail with reference to Examples.
実施例 １
特級試薬のジチオン酸ナトリウムを用いてジチ
オン酸イオン500ppm容液を調製し、これにアル
カリ処理後のPHを想定して水酸化カルシウムを添
加してPHを11としたのち、ポリ塩化アルミニウム
をAl2O3として500ppmを添加し、さらに水酸化
カルシウムを添加してPHを12として、生成したジ
チオン酸イオンを含む沈殿を別した後、酸塩で
PHを中性付近まで調整した液についてジチオン酸
イオン濃度を測定したところ、4.4ppmであつ
た。従つて、ジチオン酸イオンの除去率は99.1％
である。また、上記と同様に調製したジチオン酸
イオン1000ppm溶液にポリ塩化アルミニウムを
Al2O3として500ppm添加し、上記と同様に処理
したところ、ジチオン酸イオン濃度は8.8ppmに
低下した。従つて、この場合もジチオン酸イオン
の除去率は99.1％である。Example 1 A 500 ppm solution of dithionate ions was prepared using sodium dithionate, a special grade reagent, and calcium hydroxide was added to this to adjust the pH to 11, assuming the pH after alkali treatment, and then polyaluminum chloride was added. was added as Al 2 O 3 at 500 ppm, and then calcium hydroxide was added to adjust the pH to 12. After separating the generated precipitate containing dithionate ions, it was mixed with an acid salt.
When the dithionate ion concentration of the solution whose pH was adjusted to around neutrality was measured, it was 4.4 ppm. Therefore, the removal rate of dithionate ion is 99.1%
It is. In addition, polyaluminum chloride was added to a 1000 ppm dithionate ion solution prepared in the same manner as above.
When 500 ppm of Al 2 O 3 was added and treated in the same manner as above, the dithionate ion concentration decreased to 8.8 ppm. Therefore, in this case as well, the removal rate of dithionate ions was 99.1%.
実施例 ２
石炭を燃料としたボイラの排ガスを石灰石―石
こう法湿式排煙脱硫装置に導き、該装置から排出
された排煙脱硫廃液（ジチオン酸イオン濃度
1113ppm）のPHを水酸化カルシウムにて11に調
整してSSおよび重金属類を別したのち、ポリ
塩化アルミニウムをAl2O3として1000ppm添加
し、さらに、水酸化カルシウムを加えて廃液のPH
を12とした。この時、生成した沈殿を別し、
液中のジチオン酸イオン濃度を測定したところ、
5.5ppmであつた。従つて、ジチオン酸イオンの
除去率は99.5％である。Example 2 Exhaust gas from a coal-fired boiler was introduced into a limestone-gypsum wet flue gas desulfurization system, and the flue gas desulfurization waste liquid (dithionate ion concentration) discharged from the equipment was evaluated.
After adjusting the pH of the waste liquid (1113ppm) to 11 with calcium hydroxide and separating SS and heavy metals, 1000ppm of polyaluminum chloride was added as Al 2 O 3 , and then calcium hydroxide was added to adjust the pH of the waste liquid.
was set to 12. At this time, separate the generated precipitate,
When the concentration of dithionate ion in the liquid was measured,
It was 5.5ppm. Therefore, the removal rate of dithionate ions is 99.5%.
図面は石灰石―石こう法湿式排煙脱硫工程を含
めての本発明の一実施例のフローシートである。
図において、
…石灰石―石こう法湿式排煙脱硫工程、…
本発明の湿式排煙脱硫廃液処理工程、１…排ガス
の除じん工程、２…SO2吸収工程、３…酸化工
程、４…石こう分離工程、５…凝集沈殿処理工
程、６…ジチオン酸イオン分離除去工程、７…炭
酸カルシウム回収工程、８…PH調節工程、９…
過工程、１０…石灰スラリー、１１…アルカリ剤
（水酸化カルシウム）、１２…アルミニウムイオン
を含む無機系凝集剤（ポリ塩化アルミニウム）、
１３…アルカリ剤（水酸化カルシウム）、１４…
炭酸ナトリウム、１５…酸（塩酸）、１６…排ガ
ス、１７…脱硫排ガス、１８…スラツジ、１９…
ジチオン酸イオンを含むスラツジ、２０…回収炭
酸カルシウム、２１…水酸化アルミニウム、２２
…処理水。
The drawing is a flow sheet of an embodiment of the present invention including a limestone-gypsum wet flue gas desulfurization process.
In the figure, ...limestone-gypsum wet flue gas desulfurization process,...
Wet flue gas desulfurization waste liquid treatment process of the present invention, 1... flue gas dust removal process, 2... SO 2 absorption process, 3... oxidation process, 4... gypsum separation process, 5... coagulation precipitation treatment process, 6... dithionate ion separation Removal step, 7... Calcium carbonate recovery step, 8... PH adjustment step, 9...
10... Lime slurry, 11... Alkaline agent (calcium hydroxide), 12... Inorganic flocculant containing aluminum ions (polyaluminum chloride),
13...Alkaline agent (calcium hydroxide), 14...
Sodium carbonate, 15... acid (hydrochloric acid), 16... exhaust gas, 17... desulfurization exhaust gas, 18... sludge, 19...
Sludge containing dithionate ions, 20... Recovered calcium carbonate, 21... Aluminum hydroxide, 22
...treated water.
Claims (1)
るジチオン酸イオンを含む廃液の処理方法におい
て、該廃液をアルカリ処理したのち過し、該
過された廃液にアルミニウムイオンを含む無機系
凝集剤を加え、さらにアルカリ剤でPHを10以上に
してジチオン酸イオンを凝集沈殿させることを特
徴とする湿式排煙脱硫廃液処理方法。1. In a method for treating waste liquid containing dithionate ions discharged from a limestone-gypsum method flue gas desulfurization process, the waste liquid is treated with an alkali and then filtered, and an inorganic flocculant containing aluminum ions is added to the filtered waste liquid. A wet flue gas desulfurization waste liquid treatment method characterized by further raising the pH to 10 or higher using an alkaline agent to coagulate and precipitate dithionate ions.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP10595678A JPS5547181A (en) | 1978-08-30 | 1978-08-30 | Wet type treatment of waste water from waste gas desulfurization |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP10595678A JPS5547181A (en) | 1978-08-30 | 1978-08-30 | Wet type treatment of waste water from waste gas desulfurization |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS5547181A JPS5547181A (en) | 1980-04-03 |
| JPS6232995B2 true JPS6232995B2 (en) | 1987-07-17 |
Family
ID=14421262
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP10595678A Granted JPS5547181A (en) | 1978-08-30 | 1978-08-30 | Wet type treatment of waste water from waste gas desulfurization |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS5547181A (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2551116Y2 (en) * | 1991-05-27 | 1997-10-22 | 松下電工株式会社 | Bathtub support structure |
| CN100450943C (en) * | 2006-12-31 | 2009-01-14 | 湖南华迪电力环保工程技术有限公司 | Method and system unit for flue gas desulfurization and wastewater treatment |
-
1978
- 1978-08-30 JP JP10595678A patent/JPS5547181A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5547181A (en) | 1980-04-03 |
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