JPS608961B2 - Manufacturing method of high concentration sodium hypochlorite aqueous solution - Google Patents

Description

【発明の詳細な説明】 本発明は高濃度次亜塩素酸ソーダ水溶液の製造方法に関
する。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a highly concentrated aqueous solution of sodium hypochlorite.

詳しくは苛性ソーダと塩素とを反応させるに際し、４５
〜５５％苛性ソーダを反応器液面より、一方塩素ガスー
水混合物を反応器底部ノズルより連続的に供給して反応
させる方法である。苛性ソーダ水溶液と塩素ガスを反応
させ次亜塩素酸ソーダ水溶液を得る場合、生成する食塩
の結晶が析出しないようにするには苛性ソーダ濃度を約
２０％以下とする必要がある。For details, when reacting caustic soda and chlorine, 45
This is a method in which ~55% caustic soda is continuously supplied from the liquid level of the reactor, while a chlorine gas-water mixture is continuously supplied from the nozzle at the bottom of the reactor. When a sodium hypochlorite aqueous solution is obtained by reacting a caustic soda aqueous solution with chlorine gas, the caustic soda concentration needs to be about 20% or less in order to prevent the resulting salt crystals from precipitating.

この条件での反応液は有効塩素濃度１２〜１３％、食塩
１０〜１２％であり、室温程度では食塩は析出しない。
これ以上の有効塩素濃度を得るには原料苛性ソーダ濃度
を高くする必要がある。しかし苛性ソーダ濃度が高くな
るに従い、液の粘度も高くなり、塩素ガスの液中での分
散が悪くなり局部的な過塩素化反応を起こす。The reaction solution under these conditions has an effective chlorine concentration of 12 to 13% and a common salt concentration of 10 to 12%, and the common salt does not precipitate at about room temperature.
To obtain a higher effective chlorine concentration, it is necessary to increase the raw material caustic soda concentration. However, as the concentration of caustic soda increases, the viscosity of the liquid also increases, and the dispersion of chlorine gas in the liquid becomes poor, causing a localized hyperchlorination reaction.

これは塩素ガスの原単位を悪くするだけでなく、連鎖反
応を引き起こし反応液全体を塩素酸ソーダと食塩に分解
し、その反応熱により設備破損の危険性をもつ。また析
出する食塩結晶によるトラブルも多く、液中に閉口した
塩素ガスノズルが語り易く定量的供繋台が不可能となり
、反応液の品位もばらつくばかりでなく、結晶粒径も細
かくなりその後の分離に支障をきたす。特に４０〜５０
％苛性ソーダ水溶液に塩素ガスをバッチ式で導適する場
合、その反応初期においてはほとんどの塩素ガスが吸収
されないまま液面に浮上し、理論量の塩素ガスを吸収さ
せるには長時間を要し実際的ではなく、析出する結晶も
細かく分離が困難である。This not only worsens the unit consumption of chlorine gas, but also causes a chain reaction, decomposing the entire reaction solution into sodium chlorate and salt, and the reaction heat poses a risk of equipment damage. In addition, there are many troubles caused by precipitated salt crystals, and a chlorine gas nozzle that is closed in the liquid makes it impossible to establish a quantitative feeder.Not only does the quality of the reaction liquid vary, but the crystal grain size also becomes fine, making it difficult for subsequent separation. cause trouble. Especially 40-50
% caustic soda aqueous solution in a batch process, most of the chlorine gas rises to the surface of the liquid without being absorbed in the early stages of the reaction, and it takes a long time to absorb the theoretical amount of chlorine gas, making it impractical. However, the precipitated crystals are also difficult to separate finely.

また連続して当量的に苛性ソーダと塩素ガスを供Ｖ給す
るとしても、短期間で塩素ガスノズルが詰まり、洗浄が
必要となり、定常的な供Ｖ給は不可能となる。Furthermore, even if caustic soda and chlorine gas are continuously supplied in equivalent amounts, the chlorine gas nozzle will become clogged in a short period of time, requiring cleaning, making constant supply impossible.

塩素ガスの不規則な導通は局部的な過塩素化を起こした
り、液組成に変動をきたし液品質、食塩結晶粒径をばら
つかせる原因となる。本発明者等はこのような状況にお
いて安定したしかも高品質の高濃度次亜塩素酸ソーダ水
溶液の製造方法について種々研究した結果、下記の如き
知見を得て本発明に至った。すなわち４５〜５５％の苛
性ソーダ水溶液と塩素ガスを連続的に供総合・する方法
として苛性ソーダは反応器液面より、一方塩素ガスは適
量の水と混合させ反応器液底部のノズルより吹き出させ
ることにより過塩素化反応が抑えられ、高品位の高濃度
次蓮塩素酸ソ〜ダ水溶液が得られる。Irregular conduction of chlorine gas causes localized hyperchlorination and changes in liquid composition, causing variations in liquid quality and salt crystal grain size. The inventors of the present invention conducted various studies on a method for producing a high-concentration sodium hypochlorite aqueous solution that is stable and of high quality under such circumstances, and as a result, they obtained the following knowledge and arrived at the present invention. That is, as a method of continuously combining 45 to 55% caustic soda aqueous solution and chlorine gas, the caustic soda is mixed with the reactor liquid level, while the chlorine gas is mixed with an appropriate amount of water and blown out from a nozzle at the bottom of the reactor liquid. The perchlorination reaction is suppressed, and a high-quality, highly concentrated sodium hypochlorite aqueous solution can be obtained.

また過塩素化の危険が少なく析出する食塩結晶の粒径も
大きく、その後の分離操作上有利であるばかりでなく、
塩素ガスノズルの詰りは全然なく安定した運転が得られ
る。本発明による高濃度次亜塩素酸ソーダ水溶液製造は
具体的には次のようにして得られる。In addition, there is less risk of overchlorination, and the grain size of the precipitated salt crystals is large, which is not only advantageous for subsequent separation operations, but also
There is no clogging of the chlorine gas nozzle and stable operation is achieved. Specifically, the high concentration sodium hypochlorite aqueous solution according to the present invention can be produced as follows.

蝿伴機、冷却コイル、反応液オーバーフロー口を具備し
た反応器に市販次亜塩素酸ソーダ水溶液（有効塩素１２
〜１３％、食塩１０〜１２％）を仕込む。A commercially available sodium hypochlorite aqueous solution (available chlorine 12
-13%, salt 10-12%).

次に４５〜５５％苛性ソーダ溶液を液面上より、一方塩
素ガスを反応器底部に取付けた分散ノズルより供Ｖ給す
る。この時塩素ガスはノズルより上流部において供給し
た水と充分混合された後吹出させる。その後所定の液ｐ
Ｈ、温度になるよう調整しながら連続的に反応させる。
反応液はオーバ−フロー出口より回収し、沈降槽あるい
は遠心分離機で固液分離する。ここにおいて供給する水
の童は０．３〜１．が２０ｋ９／ＣＩ２ｋ９が適当であ
り、これより低い範囲ではノズルのつまりをきたし、高
い範囲では液濃度が低くなり、高濃度次亜塩素酸ソーダ
水溶液が得にくくなる。また塩素ガスと水の混合の具合
は単にノズル近辺においてガスと水とを接触させるだけ
では効果がなく、水をある程度ミスト化できる混合部が
必要である。Next, a 45-55% caustic soda solution is supplied from above the liquid level, while chlorine gas is supplied from a dispersion nozzle attached to the bottom of the reactor. At this time, the chlorine gas is sufficiently mixed with the supplied water at the upstream portion of the nozzle and then blown out. Then the prescribed liquid p
H. Continuously react while adjusting the temperature.
The reaction solution is collected from the overflow outlet and subjected to solid-liquid separation in a sedimentation tank or centrifuge. The water child supplied here is 0.3 to 1. A suitable value is 20k9/CI2k9; if the range is lower than this, the nozzle will clog, and if it is higher than this, the liquid concentration will be low and it will be difficult to obtain a high concentration sodium hypochlorite aqueous solution. Furthermore, regarding the mixing of chlorine gas and water, simply bringing the gas and water into contact in the vicinity of the nozzle is not effective; a mixing section that can turn the water into a certain amount of mist is required.

このようにして連続反応を行なうときは局部的な過塩素
化が抑えられ、反応器よりオーバーフロ−してくる生成
液中の塩素酸ソーダの濃度は０．１〜０．２％と低く、
塩素ガスのみを吹き込む方法に比べ１／５〜１／３とな
っており、品質の良い高濃度次亜塩素酸ソーダ水溶液が
得られる。When performing continuous reactions in this way, local overchlorination is suppressed, and the concentration of sodium chlorate in the product solution overflowing from the reactor is as low as 0.1 to 0.2%.
This is 1/5 to 1/3 compared to the method of blowing only chlorine gas, and a high-concentration sodium hypochlorite aqueous solution of good quality can be obtained.

これは塩素ガス吹出しノズル近辺で起こると考えられる
過塩素化反応が塩素ガスと同時に同じノズルより供ｖ給
される水の存在により緩和されるものと考えられる。す
なわち吹き出しノズル近辺で反応生成した次亜塩素酸ソ
ーダがすぐ後に続く塩素と直接接触する頻度が低くなる
ためと推測される。またこの供９者水の存在は食塩結晶
が析出する領域において液粘度、液費を変え、ノズル近
辺での２次核の発生を抑え結晶が成長しやすい条件をつ
くり、そのため析出する食塩結晶が４００〜４５０〃の
粒径にまで成長し、その分離を容易にする。更に本発明
方法においては塩素ガスノズルのつまりが全くなく、塩
素ガス吹出し圧は反応器液深さ圧のみ程度でよく、殆ん
ど変動なく長時間に亘る連続運転が安定して行ない得る
。従って高圧設備を必要としない。次に上記発明の効果
を実施例を用いて述べる。This is thought to be because the perchlorination reaction that is thought to occur near the chlorine gas blowing nozzle is alleviated by the presence of water that is supplied from the same nozzle at the same time as the chlorine gas. In other words, it is presumed that this is because the frequency of direct contact between the sodium hypochlorite generated by the reaction near the blowing nozzle and the chlorine that immediately follows becomes lower. In addition, the presence of this water changes the liquid viscosity and liquid flow in the region where salt crystals precipitate, suppressing the generation of secondary nuclei near the nozzle, and creating conditions that facilitate crystal growth. It grows to a particle size of 400 to 450 mm, making it easy to separate. Further, in the method of the present invention, there is no clogging of the chlorine gas nozzle, and the chlorine gas blowing pressure only needs to be the depth pressure of the reactor liquid, so that continuous operation can be carried out stably for a long time with almost no fluctuation. Therefore, high pressure equipment is not required. Next, the effects of the above invention will be described using examples.

実施例 １涜梓機（３０仇ｐｍ）「冷却コイル、オーバ
ーフロー出口、底部に４柵で×４ケのＣＩ２吹き出しノ
ズルを持ち、供給水が一時保持される環状の供給管を持
つ２５その反応器に市販の次亜塩素酸ソーダ水溶液を仕
込み、次に４９％苛性ソーダを１８．８ｋ９／ｈｒで液
面上より、一方塩素ガスは上流で水と浪合（塩素７．８
ｋ９／ｈｒ、水５．５ｋｇ／ｈｒ、公○／ＣＩ＝０．７
）させ「底部環状供給管より吹き出させ、反応液はオー
バーフロー出口より回収する。Example 1 Reactor (30 pm) with a cooling coil, an overflow outlet, 4 CI2 blowout nozzles with 4 rails at the bottom, and an annular supply pipe in which the feed water is temporarily held. A commercially available sodium hypochlorite aqueous solution was charged into the tank, and then 49% caustic soda was added above the liquid level at 18.8 k9/hr, while chlorine gas was mixed with water upstream (chlorine 7.8
k9/hr, water 5.5kg/hr, public ○/CI=0.7
) and the reaction solution is blown out from the bottom annular supply pipe, and the reaction solution is collected from the overflow outlet.

５ｑ時間連続運転を行なったが、この間塩素吹出し圧は
０．１ｋ９／の程度で全然変化なく、反応温度２３〜２
５ｑｏ、ＰＨ１３．４〜１３．６で安定した運転が可能
であった。Continuous operation was carried out for 5 q hours, during which time the chlorine blowing pressure remained at around 0.1 k9/, with no change at all, and the reaction temperature was 23 to 2.
Stable operation was possible at 5 qo and pH 13.4 to 13.6.

４時間おきに反応液をサンプリング分析したがほとんど
一定であった。The reaction solution was sampled and analyzed every 4 hours, but it was almost constant.

反応開始後８時間経過のオーバーフロー液分析結果では
反応液組成は有効塩素２４．０％、食塩２０．７％水酸
化ナトリウム０．９５％、塩素酸ソーダ０．１５％であ
った。この反応液を遠心分離機にかけ食塩を分離したと
ころ平均粒蓬４９５仏の結晶が得られ、炉液組成は有効
塩素２８．２％、食塩６．５％、水酸化ナトリウム１．
１３％、塩素酸ソーダ０．１８％であった。実施例 ２ 実施例１と同じ装遭を用い市販次亜塩素酸ソーダ水溶液
を仕込んだ後、５２．８％苛性ソーダを１６．１ｋ９／
ｈｒ、塩素ガス７．５ｋｇ／ｈｒ、混合水７．５ｋｇ／
ｈｒ（混合比日２０／ＣＩ２＝１．０）で供給した。Analysis of the overflow liquid 8 hours after the start of the reaction revealed that the composition of the reaction liquid was 24.0% available chlorine, 20.7% common salt, 0.95% sodium hydroxide, and 0.15% sodium chlorate. When this reaction solution was centrifuged to separate the common salt, crystals with an average grain size of 495 Buddhas were obtained, and the furnace liquid composition was 28.2% available chlorine, 6.5% common salt, and 1.5% sodium hydroxide.
13%, and sodium chlorate 0.18%. Example 2 Using the same container as in Example 1, a commercially available sodium hypochlorite aqueous solution was charged, and then 52.8% caustic soda was added at 16.1k9/ml.
hr, chlorine gas 7.5kg/hr, mixed water 7.5kg/hr
hr (mixing ratio day 20/CI2=1.0).

約３■時間の連続運転中塩素吹き込み圧は０．０８ｋ９
ノｈｒで一定、反応温度２６〜２８００、ＰＨ１３．５
〜１３．７でコントロールされた。反応開始後８時間経
過のオーバーフロー液を分析したところ、有効塩素２２
．５％、食塩１９．３％、水酸化ナトリウム１．１０％
、塩素酸ソーダ０．１３％であった。この反応液を遠心
分離機にかけて食塩を分離したところ平均粒径４７０ム
の結晶が得られ、炉液組成は有効塩素２５．６％、食塩
６．８％、塩素酸ソーダ０．１５％であった。比較例
１ 凝杵機（３０比ｐｍ）、冷却コイル、液オーバーフロー
出口、底部に４柵？×４ケのノズルのある塩素供Ｖ給管
をもつ２５そのの反応器に市販の次亜塩素酸ソーダ水溶
液を仕込み、次に３７．９％の苛性ソーダを液面上より
２７．２ｋ９／ｈｒ、塩素をノズルより８．９５ｋ９／
ｈｒで吹き出させた。During continuous operation for approximately 3 hours, the chlorine injection pressure was 0.08k9.
Constant hr, reaction temperature 26-2800, pH 13.5
It was controlled at ~13.7. Analysis of the overflow liquid 8 hours after the start of the reaction revealed that available chlorine was 22.
．． 5%, salt 19.3%, sodium hydroxide 1.10%
, sodium chlorate 0.13%. When this reaction solution was centrifuged to separate the salt, crystals with an average particle size of 470 μm were obtained, and the furnace liquid composition was 25.6% available chlorine, 6.8% common salt, and 0.15% sodium chlorate. Ta. Comparative example
1. Condensing machine (30 pm), cooling coil, liquid overflow outlet, 4 bars at the bottom? A commercially available sodium hypochlorite aqueous solution was charged into a 25 reactor equipped with a chlorine supply V pipe with 4 nozzles, and then 37.9% caustic soda was added from above the liquid level at a rate of 27.2k9/hr. 8.95k9/chlorine from the nozzle
I burst out with hr.

反応液はオーバーフロー出口より取り出した。この反応
では結晶析出後約３０分程度で塩素ノズルがつまり、圧
力がｌｋｇ／の以上に上昇した、２ｋ９／地上昇した時
点で反応を止めノズルを水洗した。その後１５〜３０分
に１回の頻度でノズルを水洗しながら塩素化反応を続け
た。この間塩素吹き込み圧力は１．５〜２．２ｋ９／地
、反応温度２１〜２ｙｏ、ＰＨ１３．２〜１３．７であ
った。反応開始後８時間経過の反応液組成は有効塩素２
２．９％、食塩２１．０％、水酸化ナトリウム０．９３
％、塩素酸ソーダ０．６２％であった。遠心分離後の炉
液組成は有効塩素２６．５％、食塩７−０％、水酸化ナ
トリウム１．１％、塩素酸ソーダ０．７３％であった。
また食塩結晶の平均的粒径は１８０仏であった。比較例
２比較例１とノズル径だけ違い（６側ぐ×４ケ）他は
同じ装置を用い、４０％苛性ソーダ２０ｋ９／ｈｒ塩素
ガス７．２ｋ９ノｈｒで供給した。The reaction solution was taken out from the overflow outlet. In this reaction, the chlorine nozzle became clogged about 30 minutes after crystal precipitation, and the reaction was stopped when the pressure rose to more than 1 kg/kg, or 2k9/kg, and the nozzle was washed with water. Thereafter, the chlorination reaction was continued while washing the nozzle with water once every 15 to 30 minutes. During this time, the chlorine blowing pressure was 1.5 to 2.2 k9/kg, the reaction temperature was 21 to 2 yo, and the pH was 13.2 to 13.7. The reaction liquid composition 8 hours after the start of the reaction was 2 available chlorine.
2.9%, salt 21.0%, sodium hydroxide 0.93
%, and sodium chlorate 0.62%. The composition of the furnace liquid after centrifugation was 26.5% available chlorine, 7-0% common salt, 1.1% sodium hydroxide, and 0.73% sodium chlorate.
Moreover, the average particle size of the salt crystals was 180 mm. Comparative Example 2 The same equipment as Comparative Example 1 was used except for the nozzle diameter (6 side holes x 4 holes), and 40% caustic soda was supplied at 20 k9/hr and chlorine gas was supplied at 7.2 k9/hr.

食塩結晶析出後約１８分で塩素吹き出し庄がｌｋ９／係
まで上昇した。２．０ｋ９ノ地上昇するごとに反応をス
トップしてノズルを水洗しながら反応を続けた。Approximately 18 minutes after the salt crystals were deposited, the chlorine pressure increased to lk9. The reaction was stopped every time the temperature rose by 2.0k9, and the reaction was continued while washing the nozzle with water.

Claims (1)

【特許請求の範囲】[Claims] １ 苛性ソーダと塩素を反応させて高濃度の次亜塩素酸
ソーダ溶液を得るに際し、４５〜５５％の苛性ソーダを
反応器液面より、一方塩素ガスを０．３〜１．２Ｈ＿２
Ｏｋｇ／Ｃｌ＿２ｋｇの塩素ガス−水混合物として反応
器底部ノズルより連続的に供給して反応させることを特
徴とする高濃度次亜塩素酸ソーダ水溶液の製造法。1. When reacting caustic soda and chlorine to obtain a highly concentrated sodium hypochlorite solution, 45-55% caustic soda is added from the reactor liquid level, while chlorine gas is added 0.3-1.2H_2
A method for producing a high-concentration sodium hypochlorite aqueous solution, which is characterized in that a chlorine gas-water mixture of Okg/Cl_2kg is continuously supplied from a nozzle at the bottom of a reactor and reacted.