JP2013095640A - Method for continuously regenerating sulfuric acid containing organic matter - Google Patents
Method for continuously regenerating sulfuric acid containing organic matter Download PDFInfo
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Abstract
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本発明は芳香族炭化水素−ホルムアルデヒド樹脂を製造する際に発生する有機物含有廃硫酸を、過酸化水素を利用して連続的に再生する方法に関する。 The present invention relates to a method for continuously regenerating organic-containing waste sulfuric acid generated when producing an aromatic hydrocarbon-formaldehyde resin using hydrogen peroxide.
従来より、芳香族炭化水素とホルムアルデヒドを硫酸触媒下で反応させて、芳香族炭化水素−ホルムアルデヒド樹脂を製造することが実施されているが、製造する際に発生する廃硫酸中には、硫酸分の他にホルムアルデヒドや微量の樹脂成分といった有機物が残留している。
また、ホルムアルデヒド源としてホルマリンを使用した場合にはメタノールも残留している。そのためこの廃硫酸は、硫酸酸性下での過マンガン酸カリウムCOD測定法(工場排水試験法JIS K 0102 17)(以下でCODMnと称す)でのCODMn値が高く、これらの有機物を処理することなく芳香族炭化水素−ホルムアルデヒド樹脂製造に再使用した場合は、樹脂が着色したり、品質の低下を招くことが分っている。
Conventionally, an aromatic hydrocarbon-formaldehyde resin is produced by reacting an aromatic hydrocarbon with formaldehyde in the presence of a sulfuric acid catalyst. In addition, organic substances such as formaldehyde and a small amount of resin components remain.
In addition, when formalin is used as the formaldehyde source, methanol remains. For this reason, this waste sulfuric acid has a high COD Mn value in the potassium permanganate COD measurement method (factory drainage test method JIS K 0102 17) (hereinafter referred to as COD Mn ) under sulfuric acid acidity. It has been found that when it is reused in the production of aromatic hydrocarbon-formaldehyde resin without any problem, the resin is colored or the quality is deteriorated.
また、この有機物が残留した廃硫酸は反応における生成水やホルムアルデヒド源としてホルマリンを使用した場合に含まれる水分により硫酸濃度が低下しており、単純な濃縮では白濁や着色をしてしまうため、このまま芳香族炭化水素−ホルムアルデヒド樹脂製造に再使用した場合はやはり樹脂が着色したり、品質の低下を招いてしまう。 In addition, the waste sulfuric acid in which this organic matter remains is reduced in sulfuric acid concentration due to the water contained in the reaction when the formalin is used as the product water or formaldehyde source. When it is reused in the production of aromatic hydrocarbon-formaldehyde resin, the resin is still colored or the quality is deteriorated.
したがって、廃硫酸を芳香族炭化水素−ホルムアルデヒド樹脂製造反応の触媒として循環利用することはコスト面及び樹脂品質において不利である。そのため、酸化剤を用いて有機物を分解し、適度なpHに調整後に酸化剤を分解剤で処理して放流する方法や、適度なpHに調整後、大希釈して活性汚泥処理するか焼却処分する方法をとっているのが現状である。 Therefore, it is disadvantageous in terms of cost and resin quality to recycle waste sulfuric acid as a catalyst for aromatic hydrocarbon-formaldehyde resin production reaction. For this reason, organic substances are decomposed using an oxidant, adjusted to an appropriate pH, treated with the oxidant with a decomposing agent, discharged, adjusted to an appropriate pH, and then diluted with activated sludge or incinerated. The current method is to do this.
また、この廃硫酸には前述のようにホルムアルデヒドが含まれる。したがって、そのまま排水のpH調整に使用することは、活性汚泥の活性低下につながる。 The waste sulfuric acid contains formaldehyde as described above. Therefore, using as it is for adjusting the pH of the wastewater leads to a decrease in the activity of the activated sludge.
同様に、この廃硫酸もしくは再生硫酸に過酸化水素などの酸化剤が混入または残存している場合、排水のpH調整にそのまま使用すると活性汚泥の著しい活性低下につながる。また、これを芳香族炭化水素−ホルムアルデヒド樹脂製造の触媒として再使用すると、樹脂の収率や品質の低下を招く。 Similarly, when an oxidizing agent such as hydrogen peroxide is mixed in or remains in the waste sulfuric acid or the regenerated sulfuric acid, if used as it is for adjusting the pH of the wastewater, the activated sludge is significantly reduced in activity. Further, when this is reused as a catalyst for producing an aromatic hydrocarbon-formaldehyde resin, the yield and quality of the resin are reduced.
一方で、廃硫酸を冷却器付きで還流反応にて過酸化水素処理した後、濃縮した再生硫酸を得て、芳香族炭化水素−ホルムアルデヒド樹脂製造の反応触媒として再使用する芳香族炭化水素−ホルムアルデヒド樹脂製造廃液の有効利用法はすでに公知である。（特許文献１参照）。 On the other hand, after the waste sulfuric acid is treated with hydrogen peroxide by reflux reaction with a cooler, concentrated regenerated sulfuric acid is obtained and reused as a reaction catalyst for the production of aromatic hydrocarbon-formaldehyde resin. The effective utilization method of resin production waste liquid is already known. (See Patent Document 1).
しかしながら、特許文献１の方法で廃硫酸処理を実施すると処理工程数が煩雑となるばかりでなく、設備規模に対する時間当たりの処理量は著しく悪い。 However, when the waste sulfuric acid treatment is performed by the method of Patent Document 1, not only the number of treatment steps becomes complicated, but the treatment amount per hour with respect to the equipment scale is remarkably bad.
また、特許文献１の方法では、メタノール濃度が1.5質量％を超えるような高濃度の場合はたとえ過酸化水素濃度を高くしたとしても有機物、特にメタノールの分解処理が不十分となり、経済的に不利であるばかりでなく、CODMn値が高く着色した再生硫酸となる。 Further, in the method of Patent Document 1, when the concentration of methanol exceeds 1.5% by mass, even if the concentration of hydrogen peroxide is increased, the decomposition of organic matter, particularly methanol, is insufficient, which is economically disadvantageous. In addition, the regenerated sulfuric acid is colored with a high COD Mn value.
また、濃縮の際に留去した水側にも硫酸が含まれるため、これを排水処理する設備にも耐酸性能や中和の必要があり、経済性に劣る。 Moreover, since the sulfuric acid is contained also in the water side distilled off in the case of concentration, the equipment which drains this also needs acid resistance performance and neutralization, and is inferior to economical efficiency.
さらに、濃縮の際に留去した水側には過酸化水素も残留するため、これを活性汚泥に排水する場合には、活性汚泥中のバクテリアが死滅し、活性汚泥の排水処理速度低下等の悪影響が認められた。 Furthermore, since hydrogen peroxide also remains on the water side distilled off during concentration, if this is drained into activated sludge, the bacteria in the activated sludge will be killed, and the activated sludge wastewater treatment rate will be reduced. An adverse effect was observed.
もう一方で、廃硫酸に含有される有機物を紫外線または酸化剤もしくはその両方を用いて分解したのち、濃縮蒸留して高純度の硫酸を得る再生装置は公知である。（特許文献２参照）。 On the other hand, a regenerator that obtains high-purity sulfuric acid by decomposing an organic substance contained in waste sulfuric acid using ultraviolet rays and / or an oxidizing agent and then concentrating it is known. (See Patent Document 2).
しかし、特許文献２の方法では硫酸そのものを留去させるため、膨大なエネルギーが必要となることから経済的ではない。 However, since the sulfuric acid itself is distilled off in the method of Patent Document 2, enormous energy is required, which is not economical.
また、特許文献２の装置を芳香族炭化水素−ホルムアルデヒド樹脂を製造する際に発生する廃硫酸の処理に適用しようとすると、この廃硫酸は低濃度であるため工業的に使用される殆どの金属を腐食することから設備設計が非常に困難であるだけでなく、莫大な費用がかかり経済的に不利である。 In addition, when the apparatus of Patent Document 2 is applied to the treatment of waste sulfuric acid generated when producing an aromatic hydrocarbon-formaldehyde resin, the waste sulfuric acid has a low concentration, so that most metals used industrially. In addition to making the equipment design very difficult, it is very expensive and economically disadvantageous.
さらに、特許文献２では濃縮蒸留以外の条件が示されていないが、芳香族炭化水素−ホルムアルデヒド樹脂を製造する際に発生する廃硫酸の処理に適用しようとすると、これに含有する有機物、特にメタノールを酸化剤のみですべて分解しようとする場合においては、常温では分解速度が遅く、たとえ熱をかけたとしても大量の酸化剤と長い処理時間が必要となり経済的に不利である。 Furthermore, Patent Document 2 does not show conditions other than concentrated distillation. However, when it is applied to the treatment of waste sulfuric acid generated when an aromatic hydrocarbon-formaldehyde resin is produced, organic substances contained therein, particularly methanol, are included. In the case of trying to decompose all with only an oxidizing agent, the decomposition rate is slow at room temperature, and even if heat is applied, a large amount of oxidizing agent and a long treatment time are required, which is economically disadvantageous.
また、特許文献２では分解・濃縮・蒸留において異なる装置を利用しているため、比較的大きな設備となってしまう。 Moreover, in patent document 2, since a different apparatus is utilized in decomposition | disassembly, concentration, and distillation, it will become a comparatively big installation.
また、特許文献２の有機物分解方法を芳香族炭化水素−ホルムアルデヒド樹脂を製造する際に発生する廃硫酸の処理に適用しようとすると、メタノールの分解は進むが含有する樹脂分の分解が不十分となり再生硫酸が着色することがある。 In addition, when the organic substance decomposition method of Patent Document 2 is applied to the treatment of waste sulfuric acid generated when producing an aromatic hydrocarbon-formaldehyde resin, the decomposition of methanol proceeds but the decomposition of the contained resin becomes insufficient. Regenerated sulfuric acid may be colored.
本発明は、芳香族炭化水素−ホルムアルデヒド樹脂を製造する際に発生する廃硫酸の再生において、以下（１）〜（５）を可能とする再生方法を提供することである。
（１）再生硫酸中のCODMn値が効率的に低下
（２）再生硫酸の着色が少ない（ハーゼン数100以下）
（３）再生硫酸での過酸化水素が非残留
（４）再生硫酸を、芳香族炭化水素−ホルムアルデヒド樹脂製造の触媒として再使用
（５）排水中和への利用
The present invention is to provide a regeneration method that enables the following (1) to (5) in the regeneration of waste sulfuric acid generated when an aromatic hydrocarbon-formaldehyde resin is produced.
(1) COD Mn value in regenerated sulfuric acid is efficiently reduced (2) Regenerated sulfuric acid is less colored (Hazen number of 100 or less)
(3) No residual hydrogen peroxide in the regenerated sulfuric acid (4) Reuse of the regenerated sulfuric acid as a catalyst for aromatic hydrocarbon-formaldehyde resin production (5) Use for wastewater neutralization
本発明者は、上記問題点を解決すべく鋭意検討した結果、この廃硫酸の再生方法において、廃硫酸を特定の条件を満たす連続過酸化水素処理工程及び連続濃縮工程を行うことによって、上記課題を解決できることを見出して、本発明に至った。 As a result of intensive studies to solve the above problems, the present inventor conducted the above-mentioned problem by performing a continuous hydrogen peroxide treatment step and a continuous concentration step for satisfying specific conditions of the waste sulfuric acid in this waste sulfuric acid regeneration method. As a result, the present invention has been found.
即ち、本発明は、以下（１）〜（８）記載の廃硫酸の再生方法に関するものである。
（１）
芳香族炭化水素−ホルムアルデヒド樹脂を製造する際に発生する廃硫酸中の有機物を分解し、硫酸を再生する方法であって、以下[工程I]および[工程II]からなることを特徴とする廃硫酸再生方法。
[工程I]
仕込み廃硫酸に含有されるホルムアルデヒドに対し、2〜10倍モルの過酸化水素を添加して、105〜115℃かつ710mmHg〜大気圧で反応させると同時に、低沸点成分を留去する。
[工程II]
工程Iで得られた反応液を150〜190℃かつ150mmHg〜大気圧に加熱して低沸点成分を留去し濃縮すると同時に、反応液内の有機物を分解除去し、過酸化水素を分解する。
（２）
工程Iで、仕込み廃硫酸に対して0.01〜0.36質量倍の低沸点成分を留去する(１)記載の廃硫酸再生方法。
（３)
工程IIで、仕込み廃硫酸に対して0.25〜0.56質量倍の低沸点成分を留去する(１)〜（２）記載の廃硫酸再生方法。
（４）工程Iにおいて過酸化水素を10〜360分かけて連続的または間欠的に添加することを特徴とする（１）〜（３）のいずれかに記載の廃硫酸再生方法。
（５）工程Iにおいて過酸化水素が水溶液で、過酸化水素の濃度が30〜60％である（１）〜（４）のいずれかに記載の廃硫酸再生方法。
（６）芳香族炭化水素−ホルムアルデヒド樹脂の原料である芳香族炭化水素が炭素数7〜12である（１）〜（５）のいずれかに記載の廃硫酸再生方法。
（７）芳香族炭化水素−ホルムアルデヒド樹脂の原料である芳香族炭化水素が、ｏ−キシレン、ｍ-キシレン、ｐ−キシレンおよびメシチレンから選ばれる少なくとも一つである（１）〜（６）のいずれかに記載の廃硫酸再生方法。
（８）芳香族炭化水素−ホルムアルデヒド樹脂の原料であるホルムアルデヒドが、ホルマリン由来である（１）〜（７）のいずれかに記載の廃硫酸再生方法。
That is, the present invention relates to a method for regenerating waste sulfuric acid as described in (1) to (8) below.
(1)
A method for decomposing an organic substance in waste sulfuric acid generated when producing an aromatic hydrocarbon-formaldehyde resin to regenerate sulfuric acid, comprising the following [Step I] and [Step II] Sulfuric acid regeneration method.
[Process I]
2-10 moles of hydrogen peroxide is added to the formaldehyde contained in the charged sulfuric acid and reacted at 105-115 ° C. and 710 mmHg-atmospheric pressure. At the same time, low-boiling components are distilled off.
[Process II]
The reaction liquid obtained in step I is heated to 150 to 190 ° C. and 150 mmHg to atmospheric pressure to distill off low-boiling components, and at the same time, decompose organic substances in the reaction liquid and decompose hydrogen peroxide.
(2)
The waste sulfuric acid regeneration method according to (1), wherein in step I, a low-boiling component 0.01 to 0.36 times by mass relative to the charged waste sulfuric acid is distilled off.
(3)
The waste sulfuric acid regeneration method according to (1) to (2), wherein in step II, a low-boiling component of 0.25 to 0.56 mass times with respect to the charged waste sulfuric acid is distilled off.
(4) The waste sulfuric acid regeneration method according to any one of (1) to (3), wherein hydrogen peroxide is added continuously or intermittently in Step I over 10 to 360 minutes.
(5) The waste sulfuric acid regeneration method according to any one of (1) to (4), wherein in step I, hydrogen peroxide is an aqueous solution and the concentration of hydrogen peroxide is 30 to 60%.
(6) The waste sulfuric acid regeneration method according to any one of (1) to (5), wherein the aromatic hydrocarbon which is a raw material of the aromatic hydrocarbon-formaldehyde resin has 7 to 12 carbon atoms.
(7) Any of (1) to (6), wherein the aromatic hydrocarbon which is a raw material of the aromatic hydrocarbon-formaldehyde resin is at least one selected from o-xylene, m-xylene, p-xylene and mesitylene The waste sulfuric acid reproduction | regeneration method of crab.
(8) The waste sulfuric acid regeneration method according to any one of (1) to (7), wherein formaldehyde which is a raw material of the aromatic hydrocarbon-formaldehyde resin is derived from formalin.
本発明によれば、芳香族炭化水素−ホルムアルデヒド樹脂を製造する際に発生する廃硫酸の再生において、以下（１）〜（５）が可能となる。
（１）再生硫酸中のCODMn値が効率的に低下
（２）再生硫酸の着色が少ない（ハーゼン数100以下）
（３）再生硫酸での過酸化水素が非残留
（４）再生硫酸を、芳香族炭化水素−ホルムアルデヒド樹脂製造の触媒として再使用
（５）排水中和への利用
According to the present invention, the following (1) to (5) are possible in the regeneration of waste sulfuric acid generated when producing an aromatic hydrocarbon-formaldehyde resin.
(1) COD Mn value in regenerated sulfuric acid is efficiently reduced (2) Regenerated sulfuric acid is less colored (Hazen number of 100 or less)
(3) No residual hydrogen peroxide in the regenerated sulfuric acid (4) Reuse of the regenerated sulfuric acid as a catalyst for aromatic hydrocarbon-formaldehyde resin production (5) Use for wastewater neutralization
以下、本発明を詳細に説明する。
本発明で用いる廃硫酸は芳香族炭化水素−ホルムアルデヒド樹脂を硫酸触媒下で製造する際に発生する廃硫酸が好適に用いられる。
通常、芳香族炭化水素−ホルムアルデヒド樹脂を製造する場合、目的とする樹脂組成に合わせて原料のモル比および触媒濃度を変化させる。そのため、結果的に発生する廃硫酸組成は異なる。
本発明に用いられる廃硫酸は、ホルムアルデヒド／芳香族炭化水素のモル比を0.1〜5.0とし、ホルムアルデヒドを含む水層部分の硫酸濃度（以下で単に硫酸濃度と表わすことがある）を20〜30質量％となるようにして、芳香族炭化水素−ホルムアルデヒド樹脂を製造した際に発生する。
この廃硫酸は有機物を含む硫酸水溶液で、硫酸を30〜38質量％含んでおり、有機物の含有量はホルムアルデヒドを0.3〜1.0質量％、メタノールを1.0〜5.0質量％、ギ酸を0.3〜1.0質量％、ギ酸メチルを0.05〜0.50質量％、芳香族炭化水素およびその樹脂分を0.01〜0.1質量％である。また残りの成分は水であり、この廃硫酸のCODMn値は10,000〜50,000ppmである。
Hereinafter, the present invention will be described in detail.
The waste sulfuric acid used in the present invention is preferably waste sulfuric acid generated when an aromatic hydrocarbon-formaldehyde resin is produced under a sulfuric acid catalyst.
Usually, when producing an aromatic hydrocarbon-formaldehyde resin, the molar ratio of raw materials and the catalyst concentration are changed in accordance with the intended resin composition. Therefore, the resulting waste sulfuric acid composition is different.
The waste sulfuric acid used in the present invention has a formaldehyde / aromatic hydrocarbon molar ratio of 0.1 to 5.0, and the sulfuric acid concentration in the aqueous layer containing formaldehyde (hereinafter sometimes simply referred to as sulfuric acid concentration) is 20 to 30 mass. %, It is generated when an aromatic hydrocarbon-formaldehyde resin is produced.
This waste sulfuric acid is an aqueous sulfuric acid solution containing organic matter, containing 30-38% by mass of sulfuric acid. The organic matter content is 0.3-1.0% by mass of formaldehyde, 1.0-5.0% by mass of methanol, and 0.3-1.0% by mass of formic acid. The methyl formate is 0.05 to 0.50% by mass, and the aromatic hydrocarbon and its resin content are 0.01 to 0.1% by mass. The remaining component is water, and the COD Mn value of this waste sulfuric acid is 10,000 to 50,000 ppm.
過酸化水素処理[工程I]
廃硫酸は過酸化水素を利用して含有する有機物を連続的かつ経済的に処理する。この工程Iにより廃硫酸に含まれるホルムアルデヒドおよび樹脂分は完全に酸化分解される。
過酸化水素源としては市販されている過酸化水素水をそのまま用いれば良いが、好ましくは30〜60質量％のものが用いられ、さらに好ましくは35〜45質量％のものが用いられる。過酸化水素の添加量は廃硫酸の含有する残存ホルムアルデヒド量の2〜10倍モル、好ましくは3〜5倍モルである。過酸化水素の添加量が少ないと得られる再生硫酸が着色したり、CODMn値の高いものとなり、逆に過酸化水素の添加量が多いとコスト面で不利となる。
Hydrogen peroxide treatment [Process I]
Waste sulfuric acid uses hydrogen peroxide to treat organic substances contained continuously and economically. By this step I, formaldehyde and resin contained in the waste sulfuric acid are completely oxidized and decomposed.
A commercially available hydrogen peroxide solution may be used as it is as the hydrogen peroxide source, but preferably 30 to 60% by mass, more preferably 35 to 45% by mass. The amount of hydrogen peroxide added is 2 to 10 times mol, preferably 3 to 5 times mol of the amount of residual formaldehyde contained in the waste sulfuric acid. If the added amount of hydrogen peroxide is small, the regenerated sulfuric acid obtained is colored or has a high COD Mn value. Conversely, if the added amount of hydrogen peroxide is large, it is disadvantageous in terms of cost.
工程Iに用いる装置としては耐酸性能が求められるが、加熱機能を有する攪拌槽もしくは循環装置、連続定量供給装置および熱交換器が挙げられる。また反応によるオフガス中に同伴される水分および微量の有機分を捕集するために、スクラバーの使用も行われるが、本発明は、還流反応ではないので還流冷却器は使用しない。
また、撹拌槽での攪拌は、（１）プロペラ型、半月型、アンカー型またはタービン型等の撹拌翼（２）水流による循環などが挙げられる。攪拌翼を用いた場合には、十分に接触混合が可能であれば特に限定されないが、回転数100〜600rpmが好ましい。
The apparatus used in Step I is required to have acid resistance, and examples thereof include a stirring tank or a circulation device having a heating function, a continuous quantitative supply device, and a heat exchanger. A scrubber is also used to collect moisture and a small amount of organic components that are entrained in the offgas produced by the reaction. However, since the present invention is not a reflux reaction, a reflux condenser is not used.
Further, stirring in the stirring tank includes (1) stirring blades such as a propeller type, a half moon type, an anchor type or a turbine type, and (2) circulation by a water flow. When a stirring blade is used, it is not particularly limited as long as sufficient contact mixing is possible, but a rotation speed of 100 to 600 rpm is preferable.
工程Iの温度および圧力は、105〜115℃かつ710mmHg〜大気圧で行う。好ましくは、105〜115℃かつ730mmHg〜大気圧。より好ましくは、105〜115℃かつ大気圧であり、さらに好ましくは107〜112℃かつ大気圧である。
温度および圧力が105〜115℃かつ710mmHg〜大気圧であれば、以下（１）および（２）の利点がある。
（１）廃硫酸に含まれるホルムアルデヒドおよび樹脂分の酸化分解速度が十分であり、経済性に耐え、最終的に得られる副生希硫酸はCODMnの低いものとなる。
（２）過酸化水素が自己分解で無駄に消費されコスト高となることがなく、また、廃硫酸に含まれる樹脂分の酸化分解が進み着色を抑制した再生硫酸が得られる。
また、圧力が大気圧であれば、特別な設備が不要であり、より好ましい。
The temperature and pressure in Step I are 105 to 115 ° C. and 710 mmHg to atmospheric pressure. Preferably, 105 to 115 ° C. and 730 mmHg to atmospheric pressure. More preferably, it is 105-115 degreeC and atmospheric pressure, More preferably, it is 107-112 degreeC and atmospheric pressure.
If the temperature and pressure are 105 to 115 ° C. and 710 mmHg to atmospheric pressure, the following advantages (1) and (2) are obtained.
(1) The rate of oxidative decomposition of formaldehyde and resin contained in the waste sulfuric acid is sufficient, withstands economic efficiency, and finally obtained by-product dilute sulfuric acid has a low COD Mn .
(2) Hydrogen peroxide is not wasted due to self-decomposition, resulting in an increase in cost, and a regenerated sulfuric acid in which coloring is suppressed by progressing in oxidative decomposition of the resin contained in the waste sulfuric acid.
Moreover, if the pressure is atmospheric pressure, special equipment is unnecessary, which is more preferable.
工程Iの処理時間は、連続で処理する場合において滞留時間にして0.5〜6時間、好ましくは1〜4時間、さらに好ましくは2.5〜3.5時間である。処理時間が短いと着色した再生硫酸となることがあり、長いと効率が悪く経済的に不利である。 The treatment time of Step I is 0.5 to 6 hours, preferably 1 to 4 hours, and more preferably 2.5 to 3.5 hours as a residence time in continuous treatment. If the treatment time is short, colored regenerated sulfuric acid may be produced, and if the treatment time is long, the efficiency is poor and economically disadvantageous.
工程Iでは低沸点成分を留出させる。ここで留出する低沸点成分は、メタノール、ギ酸メチル、ギ酸および水等、並びに反応で発生した一酸化炭素、二酸化炭素、酸素および水素等である。
低沸点成分を留出させながら反応を行うことで、過酸化水素処理が還流反応で行われる場合と比較して、熱効率が経済的なだけでなく、含有する有機物のうち特にメタノールを効率的に除去できて最終的なCODMn値の低減に寄与する。
この時、ガスを通気しても良いしそのままでも良く、総ガス通気量は特に規定されないが温度および圧力を維持できる程度で通気する方が好ましい。通気する場合のガスとしては、例えば、空気、窒素、ヘリウム、アルゴン、二酸化炭素等が挙げられるが、好ましくは窒素、ヘリウム、アルゴン、二酸化炭素であり、さらに好ましくは窒素である。
本発明に用いる廃硫酸を上記の温度条件で処理することで、低沸点成分は、仕込んだ廃硫酸に対し0.01〜0.36倍の質量が留去される。
In step I, a low boiling point component is distilled off. The low boiling point components distilled here are methanol, methyl formate, formic acid, water, and the like, and carbon monoxide, carbon dioxide, oxygen, hydrogen, and the like generated by the reaction.
By performing the reaction while distilling the low-boiling components, compared to the case where the hydrogen peroxide treatment is carried out by reflux reaction, not only the thermal efficiency is economical, but also methanol among the contained organic substances is efficiently. It can be removed and contributes to the reduction of the final COD Mn value.
At this time, the gas may be ventilated or may be left as it is, and the total gas aeration amount is not particularly defined, but it is preferable that the gas is vented to such an extent that the temperature and pressure can be maintained. Examples of the gas in the case of aeration include air, nitrogen, helium, argon, carbon dioxide, and the like, preferably nitrogen, helium, argon, carbon dioxide, and more preferably nitrogen.
By treating the waste sulfuric acid used in the present invention under the above temperature conditions, the low-boiling component is distilled off by 0.01 to 0.36 times the mass of the waste sulfuric acid charged.
もし、工程Iで冷却器を用いて蒸発した低沸点成分を釜に戻す還流反応を行うと、熱量が無駄になるだけでなく、芳香族炭化水素−ホルムアルデヒド樹脂を製造する際に発生する廃硫酸に含まれる水よりも沸点の低いメタノールやギ酸メチル、またギ酸が効率よく除去できず、過酸化水素の不足により着色した再生硫酸となる。
また、特にメタノールの除去不足により、CODMnの高い再生硫酸となってしまう。
If the low-boiling component evaporated using the cooler in Step I is returned to the kettle, not only is the heat lost, but also the waste sulfuric acid generated when producing the aromatic hydrocarbon-formaldehyde resin. Methanol, methyl formate, and formic acid having a boiling point lower than that of water contained in the water cannot be efficiently removed, resulting in colored regenerated sulfuric acid due to lack of hydrogen peroxide.
In particular, due to insufficient removal of methanol, regenerated sulfuric acid with high COD Mn is obtained.
工程Iの結果、工程I後の廃硫酸中に残留するメタノール濃度は1.0質量％未満となることが重要で、本発明の方法によれば最終的に着色が無くCODMn1500ppm以下を達成できる。 As a result of Step I, it is important that the concentration of methanol remaining in the waste sulfuric acid after Step I is less than 1.0% by mass. According to the method of the present invention, COD Mn of 1500 ppm or less can be finally achieved without coloring.
同時に工程I後の廃硫酸中に残留する過酸化水素濃度は2500〜15000ppmであることが好ましく、さらに好ましくは5000〜10000ppmである。5000ppm以上であれば濃縮後に着色した再生硫酸となることはなく、10000ppm以下であれば経済的に不利となることがない。
本発明の方法によれば最終的に着色が無くCODMn1500ppm以下を達成できる。
At the same time, the concentration of hydrogen peroxide remaining in the waste sulfuric acid after Step I is preferably 2500-15000 ppm, more preferably 5000-10000 ppm. If it is 5000 ppm or more, it does not become a regenerated sulfuric acid colored after concentration, and if it is 10000 ppm or less, there is no economical disadvantage.
According to the method of the present invention, there is finally no coloration and COD Mn of 1500 ppm or less can be achieved.
濃縮[工程II]
工程Iの次に、大気圧または減圧下で濃縮[工程II]する。
大気圧で濃縮する場合、ガスを通気しても良いしそのままでも良いが、ガス通気した方が好ましい。総ガス通気量は特に規定されないが、加熱温度は過酸化水素の分解温度（150℃）以上190℃以下で行うことが好ましい。
150℃未満だと再生硫酸中に過酸化水素が残留する。また、190℃より高いと硫酸が留出するため設備保全等の面で好ましくない。
通気する場合のガスとしては、例えば、空気、窒素、ヘリウム、アルゴン、二酸化炭素等が挙げられるが、好ましくは窒素、ヘリウム、アルゴン、二酸化炭素であり、さらに好ましくは窒素である。
Concentration [Step II]
Following Step I, it is concentrated [Step II] under atmospheric pressure or reduced pressure.
When concentrating at atmospheric pressure, the gas may be vented or left as it is, but it is preferred that the gas be vented. The total gas flow rate is not particularly defined, but the heating temperature is preferably a hydrogen peroxide decomposition temperature (150 ° C.) or higher and 190 ° C. or lower.
If it is lower than 150 ° C, hydrogen peroxide remains in the regenerated sulfuric acid. On the other hand, if it is higher than 190 ° C., sulfuric acid is distilled off, which is not preferable in terms of equipment maintenance.
Examples of the gas in the case of aeration include air, nitrogen, helium, argon, carbon dioxide, and the like, preferably nitrogen, helium, argon, carbon dioxide, and more preferably nitrogen.
大気圧下で濃縮する場合に用いる装置としては耐酸性能が求められ、加熱機能を有する攪拌槽もしくは循環装置、連続定量供給装置、蒸留装置および熱交換器が挙げられる。また濃縮で出たオフガス中に同伴される水分および微量の有機分を捕集するために、スクラバーの使用も行われる。
また、撹拌槽での攪拌は、（１）プロペラ型、半月型、アンカー型またはタービン型等の撹拌翼（２）水流による循環などが挙げられる。攪拌翼を用いた場合には、十分に接触混合が可能であれば特に限定されないが、回転数100〜600rpmが好ましい。
As an apparatus used in the case of concentrating under atmospheric pressure, acid resistance is required, and examples thereof include a stirring tank or a circulation apparatus having a heating function, a continuous quantitative supply apparatus, a distillation apparatus, and a heat exchanger. A scrubber is also used to collect moisture and trace amounts of organic components that are entrained in the off-gas produced by concentration.
Further, stirring in the stirring tank includes (1) stirring blades such as a propeller type, a half moon type, an anchor type or a turbine type, and (2) circulation by a water flow. When a stirring blade is used, it is not particularly limited as long as sufficient contact mixing is possible, but a rotation speed of 100 to 600 rpm is preferable.
減圧で濃縮する場合、温度および圧力は、150〜190℃かつ150mmHg以上〜大気圧未満とし、濃縮中に硫酸が留出しないように加熱を通じて、硫酸の蒸気圧を超えないように調整するのが好ましい。
上記範囲で温度および圧力を調整することにより、再生硫酸中の過酸化水素残留がなく、また留出側への過酸化水素留出もない。
また、留出側への硫酸留出もなく、収率や設備保全の面で好ましい。
この時、ガスを通気しても良いしそのままでも良いが、ガス通気した方が好ましい。総ガス通気量は特に規定されないが、温度および圧力を維持できる程度が適当である。通気する場合のガスとしては、例えば、空気、窒素、ヘリウム、アルゴン、二酸化炭素等が挙げられるが、好ましくは窒素、ヘリウム、アルゴン、二酸化炭素であり、さらに好ましくは窒素である。
When concentrating under reduced pressure, the temperature and pressure should be 150 to 190 ° C and 150 mmHg or more to less than atmospheric pressure, and adjusted so as not to exceed the vapor pressure of sulfuric acid through heating so that sulfuric acid does not distill during concentration. preferable.
By adjusting the temperature and pressure within the above ranges, there is no residual hydrogen peroxide in the regenerated sulfuric acid, and there is no hydrogen peroxide distillation to the distillation side.
Further, there is no sulfuric acid distillation to the distillation side, which is preferable in terms of yield and equipment maintenance.
At this time, the gas may be vented or may be left as it is, but it is preferable to vent the gas. The total gas flow rate is not particularly defined, but is suitable to the extent that the temperature and pressure can be maintained. Examples of the gas in the case of aeration include air, nitrogen, helium, argon, carbon dioxide, and the like, preferably nitrogen, helium, argon, carbon dioxide, and more preferably nitrogen.
減圧で濃縮する場合に用いる装置としては耐酸性能が求められ、減圧機能および加熱機能を有する攪拌槽もしくは循環装置、連続定量供給装置、蒸留装置および熱交換機が挙げられる。
減圧にする方法に特に制限はなく、真空ポンプでもエゼクターでも良い。また濃縮で出たオフガス中に同伴される水分および微量の有機分を捕集するために、スクラバーの使用も行われる。
また、撹拌槽での攪拌は、（１）プロペラ型、半月型、アンカー型またはタービン型等の撹拌翼（２）水流による循環などが挙げられる。攪拌翼を用いた場合には、十分に接触混合が可能であれば特に限定されないが、回転数100〜600rpmが好ましい。
An apparatus used for concentration under reduced pressure is required to have acid resistance, and includes a stirring tank or circulation device having a pressure reducing function and a heating function, a continuous quantitative supply device, a distillation device, and a heat exchanger.
There is no restriction | limiting in particular in the method to make pressure reduction, A vacuum pump or an ejector may be sufficient. A scrubber is also used to collect moisture and trace amounts of organic components that are entrained in the off-gas produced by concentration.
Further, stirring in the stirring tank includes (1) stirring blades such as a propeller type, a half moon type, an anchor type or a turbine type, and (2) circulation by a water flow. When a stirring blade is used, it is not particularly limited as long as sufficient contact mixing is possible, but a rotation speed of 100 to 600 rpm is preferable.
工程IIにおいて、工程I後の廃硫酸を上記の条件で処理することで、残存していた有機物は分解除去される。
また、メタノール、ギ酸メチル、ギ酸および水等、並びに反応で発生した一酸化炭素、二酸化炭素、酸素および水素等の低沸点成分は留去もされる
工程I後の廃硫酸に残存していた低沸点成分は仕込んだ廃硫酸の0.25〜0.56倍の質量で留去される。また、過酸化水素は完全に分解する。
In step II, the remaining sulfuric acid is decomposed and removed by treating the spent sulfuric acid after step I under the above conditions.
In addition, methanol, methyl formate, formic acid, water, etc., and low-boiling components such as carbon monoxide, carbon dioxide, oxygen, and hydrogen generated in the reaction are also distilled off. Boiling components are distilled off at a mass of 0.25 to 0.56 times the charged waste sulfuric acid. In addition, hydrogen peroxide is completely decomposed.
上記条件において、廃硫酸を過酸化水素処理した後に濃縮した結果、ホルムアルデヒドおよび過酸化水素は検出されず、CODMn1500ppm以下でハーゼン数5〜100の再生硫酸を得ることができる。また、その濃度は63質量％以上80質量％未満となる。 Under the above conditions, as a result of concentrating waste sulfuric acid after hydrogen peroxide treatment, formaldehyde and hydrogen peroxide are not detected, and regenerated sulfuric acid having a Hazen number of 5 to 100 at COD Mn of 1500 ppm or less can be obtained. Moreover, the density | concentration will be 63 to less than 80 mass%.
以下、実施例等により本発明を更に詳細に説明するが、本発明はこれらの例により何ら限定されるものではない。下記の例において「％」および「部」は特にことわらない限り、「質量％」および「質量部」を各々意味する。
分析方法は、次の条件に従った。
＜硫酸濃度＞
1N-NaOH水溶液による中和滴定により求めた。指示薬にはチモールフタレイン溶液を使用した。
＜残留ホルムアルデヒド濃度＞
アセチルアセトン法による発色を、分光光度計（日立社製）を使用して、420nmにおける吸収を測定して求めた。
＜残留メタノール濃度＞
パックドカラム（充填剤：ジーエルサイエンス社Porapak Q相当）を使用して、内部標準法で分析を行った。内部標準にはエタノールを使用した。
＜残留過酸化水素濃度＞
過酸化水素濃度試験紙（菱江化学社製）を使用して求めた。
EXAMPLES Hereinafter, although an Example etc. demonstrate this invention further in detail, this invention is not limited at all by these examples. In the following examples, “%” and “part” mean “% by mass” and “part by mass”, respectively, unless otherwise specified.
The analysis method followed the following conditions.
<Sulfuric acid concentration>
It was determined by neutralization titration with 1N-NaOH aqueous solution. A thymolphthalein solution was used as an indicator.
<Residual formaldehyde concentration>
Color development by the acetylacetone method was determined by measuring absorption at 420 nm using a spectrophotometer (manufactured by Hitachi).
<Residual methanol concentration>
Analysis was carried out by an internal standard method using a packed column (filler: equivalent to GL Sciences' Porapak Q). Ethanol was used as an internal standard.
<Residual hydrogen peroxide concentration>
The hydrogen peroxide concentration test paper (manufactured by Hishoe Chemical Co., Ltd.) was used.
＜参考例１＞廃硫酸を得る方法の実例
キシレン250g、40％ホルマリン354gおよび98％濃硫酸129gを反応器に仕込み、100℃にて6時間反応させた後、反応液を静置して樹脂層１と水層１に分液した。
この水層１全量387gおよびキシレン250gを反応器に仕込み、6時間反応させた後、反応液を静置して樹脂層２と水層２に分液した。
ここで得られた水層２の品質は、硫酸35％、ホルムアルデヒド0.7％、メタノール2.5％、ギ酸0.6％、ギ酸メチル0.12％、芳香族炭化水素およびその樹脂分0.04％、残りは水であり、CODMn値35000ppmであった。この水層２を芳香族炭化水素−ホルムアルデヒド樹脂を硫酸触媒下で製造した際に生ずる廃硫酸として本発明に用いた。
なお、上記、何れの反応においても反応器には攪拌機、冷却器および温度計を取り付けた同様のものを利用した。
<Reference Example 1> An example of a method for obtaining waste sulfuric acid: 250 g of xylene, 354 g of 40% formalin and 129 g of 98% concentrated sulfuric acid are charged into a reactor, reacted at 100 ° C. for 6 hours, and then the reaction solution is left to stand to form a resin. Separated into layer 1 and aqueous layer 1.
A total amount of 387 g of this aqueous layer 1 and 250 g of xylene were charged into a reactor and reacted for 6 hours, and then the reaction solution was left to separate into a resin layer 2 and an aqueous layer 2.
The quality of the aqueous layer 2 obtained here is 35% sulfuric acid, 0.7% formaldehyde, 2.5% methanol, 0.6% formic acid, 0.12% methyl formate, 0.04% aromatic hydrocarbon and its resin content, and the rest is water. The COD Mn value was 35000 ppm. This aqueous layer 2 was used in the present invention as waste sulfuric acid produced when an aromatic hydrocarbon-formaldehyde resin was produced under a sulfuric acid catalyst.
In any of the above reactions, the same reactor equipped with a stirrer, a cooler, and a thermometer was used.
＜実施例１＞
[工程I]
1Lの過酸化水素処理攪拌槽に廃硫酸500gおよび45％過酸化水素水27.8g(廃硫酸が含有する残存ホルムアルデヒド量の3倍モル)を入れ、250rpmで撹拌しながら110℃に加熱した。この際、装置には冷却器を設置せずに大気圧下で低沸点成分を留出（以下で全留出反応と称すことがある）させた。この際、通気ガスとして窒素を毎時40立方センチメートルで通気した。
攪拌槽を110℃に保持し、滞留時間が3時間となるように廃硫酸を毎時500gずつ、および45％過酸化水素水を毎時27.8gずつ連続的に仕込み、液面レベルが変化しないように連続的に抜きながら工程Iを行った。この際も、通気ガスとして窒素を毎時40立方センチメートルで通気した。
上記の工程Iにより、過酸化水素処理された無色透明の処理済み硫酸3600ｇを得た。処理済み硫酸中の各成分濃度は、硫酸37％、ホルムアルデヒド非検出、メタノール0.8％、ギ酸0.4％、ギ酸メチル0.1％、芳香族炭化水素およびその樹脂分は非検出、過酸化水素6000ppmで残りは水であった。また、CODMn値15000ppm、ハーゼン数15であった。
[工程II] 大気圧下での濃縮
工程Iの処理済み硫酸1200gを1L攪拌槽に仕込み、250rpmで撹拌しながら170℃に加熱した。この際、通気ガスとして窒素を毎時40立方センチメートルで通気し、装置には冷却器を設置せずに大気圧下で低沸点成分を留出させた。
攪拌槽を170℃に保持し、更に滞留時間が3時間となるように毎時400gずつ連続的に仕込み、液面レベルが変化しないように連続的に抜きながら大気圧下で工程IIを行った。この際も、通気ガスとして窒素を毎時40立方センチメートルで通気した。
上記操作により、無色透明の再生硫酸を1200ｇ得た。再生硫酸中の各成分濃度は、硫酸70％、メタノール0.06％、ギ酸0.0％、ギ酸メチル0.0％、残りは水で、ホルムアルデヒドおよび過酸化水素は非検出であった。また、CODMn値700ppm、ハーゼン数は20であった。この時、留去された水中から過酸化水素および硫酸は非検出であった。
<Example 1>
[Process I]
500 g of waste sulfuric acid and 27.8 g of 45% aqueous hydrogen peroxide (3 times the amount of residual formaldehyde contained in the waste sulfuric acid) were placed in a 1 L hydrogen peroxide treatment stirring tank and heated to 110 ° C. while stirring at 250 rpm. At this time, a low boiling point component was distilled off under atmospheric pressure without installing a cooler in the apparatus (hereinafter sometimes referred to as a total distillation reaction). At this time, nitrogen was vented at 40 cubic centimeters per hour as an aeration gas.
Keep the stirring tank at 110 ° C and continuously charge 500g / h of waste sulfuric acid and 27.8g / h of 45% hydrogen peroxide so that the residence time is 3 hours so that the liquid level does not change. Step I was performed with continuous removal. At this time, nitrogen was vented at 40 cubic centimeters per hour as an aeration gas.
According to the above step I, 3600 g of colorless and transparent treated sulfuric acid treated with hydrogen peroxide was obtained. Concentration of each component in the treated sulfuric acid is 37% sulfuric acid, formaldehyde not detected, methanol 0.8%, formic acid 0.4%, methyl formate 0.1%, aromatic hydrocarbon and its resin content not detected, hydrogen peroxide 6000ppm, the rest It was water. The COD Mn value was 15000 ppm and the Hazen number was 15.
[Step II] Concentration under atmospheric pressure 1200 g of the sulfuric acid treated in Step I was charged in a 1 L stirring tank and heated to 170 ° C. while stirring at 250 rpm. At this time, nitrogen was vented at 40 cubic centimeters per hour as an aeration gas, and a low boiling point component was distilled off under atmospheric pressure without installing a cooler in the apparatus.
The stirring tank was kept at 170 ° C., 400 g / h was continuously charged so that the residence time was 3 hours, and Step II was performed under atmospheric pressure while continuously removing the liquid level so as not to change. At this time, nitrogen was vented at 40 cubic centimeters per hour as an aeration gas.
By the above operation, 1200 g of colorless and transparent regenerated sulfuric acid was obtained. The concentration of each component in the regenerated sulfuric acid was 70% sulfuric acid, 0.06% methanol, 0.0% formic acid, 0.0% methyl formate, the rest was water, and formaldehyde and hydrogen peroxide were not detected. The COD Mn value was 700 ppm and the Hazen number was 20. At this time, hydrogen peroxide and sulfuric acid were not detected from the distilled water.
＜実施例２＞工程IIが減圧濃縮の例
実施例１の工程IIでの処理温度を150℃とし圧力を400mmHgとした以外は、実施例１と同様の条件で工程IIを行った。
その結果、無色透明の再生硫酸を1200ｇ得た。再生硫酸中の各成分濃度は、硫酸70％、メタノール0.05％、ギ酸0.0％、ギ酸メチル0.0％、残りは水で、ホルムアルデヒドおよび過酸化水素は非検出であった。またCODMn値650ppm、ハーゼン数25であった。この時、留去された水中から過酸化水素および硫酸は非検出であった。
<Example 2> Example in which step II is concentrated under reduced pressure
Step II was performed under the same conditions as in Example 1 except that the treatment temperature in Step II of Example 1 was 150 ° C. and the pressure was 400 mmHg.
As a result, 1200 g of colorless and transparent regenerated sulfuric acid was obtained. The concentration of each component in the regenerated sulfuric acid was 70% sulfuric acid, 0.05% methanol, 0.0% formic acid, 0.0% methyl formate, the rest was water, and formaldehyde and hydrogen peroxide were not detected. The COD Mn value was 650 ppm and the Hazen number was 25. At this time, hydrogen peroxide and sulfuric acid were not detected from the distilled water.
＜実施例３＞工程Iで温度が高い
実施例１の工程Iの温度を115℃にした以外は、実施例１と同様にした結果、硫酸濃度70％、メタノール濃度0.08％、ギ酸濃度0.0％、ギ酸メチル濃度0.1％、残りは水で、ホルムアルデヒドおよび過酸化水素は非検出であった。CODMn値1350ppm、ハーゼン数100で着色少ない、CODMn値が効率的に低下した再生硫酸が得られた。また、留去された水中から過酸化水素および硫酸は非検出であった。
なお、工程I後の処理済み硫酸中の過酸化水素は3000ppmであった。
<Example 3> Temperature is high in Step I As a result of the same as Example 1 except that the temperature in Step I of Example 1 was 115 ° C., sulfuric acid concentration 70%, methanol concentration 0.08%, formic acid concentration 0.0% The methyl formate concentration was 0.1%, the rest was water, and formaldehyde and hydrogen peroxide were not detected. A regenerated sulfuric acid having a COD Mn value of 1350 ppm, a Hazen number of 100 and low coloration, and a low COD Mn value was obtained. Further, hydrogen peroxide and sulfuric acid were not detected from the distilled water.
The hydrogen peroxide in the treated sulfuric acid after Step I was 3000 ppm.
＜実施例４＞工程I後の過酸化水素含有量の効果確認
実施例３の工程Iの結果で得られた処理液に45％過酸化水素水を添加し、過酸化水素濃度が5000ppmとなったものを実施例１の工程IIにより濃縮した結果、得られた再生硫酸は、硫酸70％、メタノール濃度が0.06％であり、CODMn値900ppm、ハーゼン数50で、ホルムアルデヒドおよび過酸化水素が非検出であった。
また、留去された水中から過酸化水素および硫酸は非検出であった。
<Example 4> Confirmation of effect of hydrogen peroxide content after step I 45% hydrogen peroxide solution was added to the treatment liquid obtained as a result of step I in Example 3, and the hydrogen peroxide concentration became 5000 ppm. As a result of concentrating the product by Step II in Example 1, the obtained regenerated sulfuric acid had 70% sulfuric acid, a methanol concentration of 0.06%, a COD Mn value of 900 ppm, a Hazen number of 50, and no formaldehyde and hydrogen peroxide. It was a detection.
Further, hydrogen peroxide and sulfuric acid were not detected from the distilled water.
＜比較例１＞工程Iが還流反応
実施例１の工程Iの反応条件のうち、装置に冷却器を設置して還流反応とした以外は、実施例１と同様にした結果、工程I後のメタノール濃度は1.6％となり、その後の工程IIにより得られた再生硫酸のメタノール濃度は0.3％であり、CODMn値は3500ppmと高くなった。
<Comparative example 1> Step I is a reflux reaction Among the reaction conditions of Step I of Example 1, except that a condenser was installed in the apparatus to make a reflux reaction, the result was the same as in Example 1; The methanol concentration was 1.6%, the methanol concentration of the regenerated sulfuric acid obtained in the subsequent Step II was 0.3%, and the COD Mn value was as high as 3500 ppm.
＜比較例２＞工程Iで反応温度が低い場合
実施例１の工程Iの反応温度を95℃とした以外は、実施例１と同様にした結果、工程I後のメタノール濃度は2.1％となり、その後の工程IIにより得られた再生硫酸のメタノール濃度は0.4％であり、CODMn値は4500ppmと高くなった。
<Comparative Example 2> When the reaction temperature is low in Step I As a result of the same as Example 1 except that the reaction temperature in Step I of Example 1 was 95 ° C, the methanol concentration after Step I was 2.1%. The methanol concentration of the regenerated sulfuric acid obtained by the subsequent step II was 0.4%, and the COD Mn value was as high as 4500 ppm.
＜比較例３＞メタノール除去が不十分の場合
実施例１の工程Iの結果で得られた処理液にメタノールを添加し、メタノール濃度が1.2％となったものを実施例１の工程II方法により濃縮した結果、得られた再生硫酸のメタノール濃度は0.2％であり、CODMn値は2500ppmと高くなった。
<Comparative Example 3> Insufficient methanol removal Methanol was added to the treatment liquid obtained as a result of Step I in Example 1, and the methanol concentration was 1.2% by the method in Step II of Example 1. As a result of concentration, the methanol concentration of the obtained regenerated sulfuric acid was 0.2%, and the COD Mn value was as high as 2500 ppm.
＜比較例４＞過酸化水素が少ない場合
実施例１の工程Iにおいて過酸化水素水添加量を毎時8.8g(廃硫酸が含有する残存ホルムアルデヒド量の1倍モル)とした以外は、実施例１と同様にした結果、工程I後の処理済み硫酸中の過酸化水素は500ppmであって、工程II後はハーゼン数300と明らかに着色した。
<Comparative example 4> When hydrogen peroxide is low
As a result of performing in the same manner as in Example 1 except that the amount of hydrogen peroxide added in Step I of Example 1 was 8.8 g per hour (1 mol of the residual formaldehyde contained in the waste sulfuric acid), the treatment after Step I was performed. Hydrogen peroxide in the spent sulfuric acid was 500 ppm, and after Step II, it was clearly colored with a Hazen number of 300.
＜比較例５＞工程Iの温度上限外
実施例１の工程Iの温度を125℃にした以外は、実施例１と同様にした結果、ハーゼン数250と明らかな着色が見られた。なお、工程I後の処理済み硫酸中の過酸化水素は1000ppmであった。
<Comparative example 5> Outside temperature upper limit of step I As a result of performing the same as in example 1 except that the temperature of step I in example 1 was set to 125 ° C, a clear coloring with a Hazen number of 250 was observed. The hydrogen peroxide in the treated sulfuric acid after Step I was 1000 ppm.
＜比較例６＞工程IIの温度上限外
実施例１の工程IIの温度を215℃にした以外は、実施例１と同様にした結果、硫酸濃度は81％となった。この時の留出には硫酸が確認され、再生硫酸収率の悪化が認められた。
<Comparative example 6> Outside temperature upper limit of step II As a result of carrying out similarly to Example 1 except having made the temperature of the process II of Example 1 into 215 degreeC, the sulfuric acid density | concentration became 81%. Sulfuric acid was confirmed in the distillate at this time, and deterioration of the regenerated sulfuric acid yield was observed.
＜比較例７＞工程IIの圧力下限外
実施例２において、工程IIの圧力を50mmHgにした以外は、実施例２と同様にした結果、硫酸濃度は85％となった。この時の留出には硫酸および過酸化水素が確認され、再生硫酸収率が悪化し、排水処理に不都合が生じた。
<Comparative example 7> Outside pressure lower limit of step II In Example 2, except that the pressure of step II was changed to 50 mmHg, the sulfuric acid concentration was 85% as a result of carrying out similarly to Example 2. At this time, sulfuric acid and hydrogen peroxide were confirmed in the distillate, and the yield of regenerated sulfuric acid deteriorated, resulting in inconvenience in wastewater treatment.
＜比較例８＞工程IIの温度下限外
実施例２において、工程IIの温度を142℃、圧力を300mmHgにした以外は、実施例２と同様にした結果、硫酸濃度は70％となった。この時の留出には過酸化水素が確認され、排水処理に不都合が生じた。
<Comparative example 8> Outside temperature lower limit of step II In Example 2, except that the temperature of step II was 142 ° C and the pressure was 300 mmHg, the sulfuric acid concentration was 70% as a result of the same as in Example 2. At this time, hydrogen peroxide was found in the distillate, which caused inconvenience in wastewater treatment.
＜参考例２＞通常の樹脂合成
キシレン250g、40％ホルマリン354gおよび98％濃硫酸129gを、攪拌機、冷却器および温度計を取り付けた反応器に仕込み、100℃にて6時間反応させた後、反応液を静置して樹脂層と水層に分液した。この樹脂層を数回水洗し、水蒸気蒸留を1時間実施した後、120℃、50mmHgにおいて1時間減圧蒸留を行い、キシレン−ホルムアルデヒド樹脂を得た。
得られたキシレン−ホルムアルデヒド樹脂は収量325g（対キシレン収率130％）、粘度350mPa・s（at 20℃）の淡黄色流動性液体であった。
<Reference Example 2> Ordinary Resin Synthesis 250 g of xylene, 354 g of 40% formalin and 129 g of 98% concentrated sulfuric acid were charged into a reactor equipped with a stirrer, a cooler and a thermometer, and reacted at 100 ° C. for 6 hours. The reaction solution was allowed to stand to separate into a resin layer and an aqueous layer. This resin layer was washed several times with water and subjected to steam distillation for 1 hour, followed by vacuum distillation at 120 ° C. and 50 mmHg for 1 hour to obtain a xylene-formaldehyde resin.
The obtained xylene-formaldehyde resin was a pale yellow fluid having a yield of 325 g (xylene yield of 130%) and a viscosity of 350 mPa · s (at 20 ° C.).
＜実施例５＞再生希硫酸利用による樹脂合成
キシレン250g、40％ホルマリン354gおよび98％濃硫酸62gと実施例１で得られた70％再生硫酸111gを反応器に仕込み、参考例２と同様の操作を行った。
得られたキシレン−ホルムアルデヒド樹脂は収量319g（対キシレン収率128％）、粘度325mPa・s（at 20℃）の淡黄色流動性液体であり、参考例２で得られたものとほとんど異ならない性状であった。
<Example 5> Resin synthesis using regenerated dilute sulfuric acid 250 g of xylene, 354 g of 40% formalin and 62 g of 98% concentrated sulfuric acid and 111 g of 70% regenerated sulfuric acid obtained in Example 1 were charged into a reactor, and the same as in Reference Example 2 The operation was performed.
The obtained xylene-formaldehyde resin is a pale yellow fluid with a yield of 319 g (with respect to xylene yield of 128%) and a viscosity of 325 mPa · s (at 20 ° C.). Met.
本発明により得られた再生硫酸は、ホルムアルデヒドおよび過酸化水素ならびに微量の樹脂も含まずCODMn値も低いため、排水中和に使用しても環境への影響が小さく、活性汚泥の活性低下が無いという大きなメリットが得られる。また、着色が無いため、樹脂製造に再利用しても樹脂品質に悪影響が無い。 The regenerated sulfuric acid obtained by the present invention does not contain formaldehyde, hydrogen peroxide, and a small amount of resin, and has a low COD Mn value. There is a big merit that there is no. Moreover, since there is no coloring, even if it reuses for resin manufacture, there is no bad influence on resin quality.
本発明によれば、芳香族炭化水素−ホルムアルデヒド樹脂を硫酸触媒下で反応した際に生じる、有機物を含有した廃硫酸からCODMn1500ppm以下でハーゼン数100以下の着色の少ない再生硫酸を得て、芳香族炭化水素−ホルムアルデヒド樹脂製造の触媒として再使用することや、排水中和に利用することができる。 According to the present invention, a regenerated sulfuric acid with less coloration having a COD Mn of 1500 ppm or less and a Hazen number of 100 or less is obtained from waste sulfuric acid containing organic matter, which is produced when an aromatic hydrocarbon-formaldehyde resin is reacted under a sulfuric acid catalyst. It can be reused as a catalyst for producing an aromatic hydrocarbon-formaldehyde resin, or used for neutralizing wastewater.
Claims (8)
[工程I]
仕込み廃硫酸に含有されるホルムアルデヒドに対し、2〜10倍モルの過酸化水素を添加して、105〜115℃かつ710mmHg〜大気圧で反応させると同時に、低沸点成分を留去する。
[工程II]
工程Iで得られた反応液を150〜190℃かつ150mmHg〜大気圧に加熱して低沸点成分を留去し濃縮すると同時に、反応液内の有機物を分解除去し、過酸化水素を分解する。 A method for decomposing an organic substance in waste sulfuric acid generated when producing an aromatic hydrocarbon-formaldehyde resin to regenerate sulfuric acid, comprising the following [Step I] and [Step II] Sulfuric acid regeneration method.
[Process I]
2-10 moles of hydrogen peroxide is added to the formaldehyde contained in the charged sulfuric acid and reacted at 105-115 ° C. and 710 mmHg-atmospheric pressure. At the same time, low-boiling components are distilled off.
[Process II]
The reaction liquid obtained in step I is heated to 150 to 190 ° C. and 150 mmHg to atmospheric pressure to distill off low-boiling components, and at the same time, decompose organic substances in the reaction liquid and decompose hydrogen peroxide.
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| EP3012275A4 (en) * | 2013-06-18 | 2016-12-14 | Mitsubishi Gas Chemical Co | Aromatic hydrocarbon formaldehyde resin, modified aromatic hydrocarbon formaldehyde resin, and epoxy resin, and method for producing said resins |
| EP3012274A4 (en) * | 2013-06-18 | 2016-12-14 | Mitsubishi Gas Chemical Co | Aromatic hydrocarbon formaldehyde resin, modified aromatic hydrocarbon formaldehyde resin, and epoxy resin, and method for producing said resins |
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