JP2006320889A - Apparatus for rendering chloroflurocarbon decomposition gas harmless - Google Patents

Apparatus for rendering chloroflurocarbon decomposition gas harmless Download PDF

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JP2006320889A
JP2006320889A JP2006039208A JP2006039208A JP2006320889A JP 2006320889 A JP2006320889 A JP 2006320889A JP 2006039208 A JP2006039208 A JP 2006039208A JP 2006039208 A JP2006039208 A JP 2006039208A JP 2006320889 A JP2006320889 A JP 2006320889A
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water
washing
absorption tower
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tower
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Masaru Kumazawa
勝 熊澤
Tadashi Nagaoka
忠 長岡
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    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
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    • Y02C20/30—Capture or disposal of greenhouse gases of perfluorocarbons [PFC], hydrofluorocarbons [HFC] or sulfur hexafluoride [SF6]

Abstract

<P>PROBLEM TO BE SOLVED: To provide an apparatus for making a hydrofluoric acid concentration in a chlorofluorocarbon decomposition gas 0 ppm by neutralizing with only water or minimum caustic soda to remove completely hydrochloric acid and hydrofluoric acid in the chlorofluorocarbon decomposition gas dispensing with a plenty of expensive NaOH and CaCl<SB>2</SB>and at the same time obtaining 1.5-2.0% hydrochloric acid and hydrofluoric acid solutions. <P>SOLUTION: In an apparatus in which a washing water is supplied to water washing and absorbing towers from a most downstream tower to a most upstream tower, the chlorofluorocarbon gas is run and off from the most upstream tower to the most down stream tower while washing water is supplied and circulated in each tower, and a water absorbed with the gas is sent to a hydrofluoric acid solution recovering side, the apparatus for rendering chlorofluorocarbon decomposition gas harmless is characterized by: providing a washing water communicating tube which communicate between adjacent washing and absorbing towers at their bottom water storage parts under their liquid surface levels; supplying water to the bottom water storage part of the most downstream water washing absorbing tower; and providing a device for supplying washing water having a structure for maintaining a liquid surface level. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

本発明は、フロン分解ガスの無害化処理装置に関するものである。詳細は水による多段ガス洗浄法を用い、フッ酸のみを含むフロン分解ガス処理の場合は、水のみで洗浄無害化し同時に高濃度で高純度のフッ酸水溶液を得る装置、および塩酸とフッ酸を含むフロン分解ガス処理の場合は、最終段で最少のアルカリ剤を用いて洗浄無害化し同時に高濃度で高純度の塩酸とフッ酸の水溶液を得る装置に関するものである。   The present invention relates to a detoxification treatment apparatus for CFC decomposition gas. For details, use a multistage gas cleaning method with water, and in the case of chlorofluorocarbon cracking gas treatment containing only hydrofluoric acid, the device is detoxified with water only, and at the same time, obtains a high concentration and high purity hydrofluoric acid aqueous solution. In the case of the chlorofluorocarbon-containing gas treatment, the present invention relates to an apparatus for detoxifying using a minimum amount of alkaline agent in the final stage and simultaneously obtaining an aqueous solution of hydrochloric acid and hydrofluoric acid with high concentration and high purity.

空調機、冷凍機、カークーラー、などに含まれる塩素を含むフロンが大気中に排出された場合には、オゾン層を破壊する。また、塩素を組成中に含まないフロンについても、フロン分子は二酸化炭素より強力な地球温暖化の原因物質であるとして、大気中に放出することが禁止されている。
フロンの分解処理法として廃棄物混焼法方式、液中燃焼方式、プラズマ法
方式、加熱蒸気反応法方式、触媒法方式がある。
加熱蒸気反応法方式は約1,000℃の高温を必要とするが触媒法方式は燐酸アルミニウムの触媒を用いることにより６２０℃の低温でフロンを分解することが出来る。
フロンを加水分解すると炭酸ガス、フッ酸ガス、塩酸ガスを生成する。
これらのガスを無害化する方法としてアルカリ液で洗浄する方式が一般的
であるが、安価なアルカリ剤として消石灰を用いると蛍石のスラッジを生成するのでバッチ運転となる。継続運転を狙いとして苛性ソーダーで中和すると蛍石の結晶を作るために塩化カルシウムの助剤を必要とする。 When chlorofluorocarbon containing chlorine contained in air conditioners, refrigerators, car coolers, etc. is discharged into the atmosphere, the ozone layer is destroyed. In addition, chlorofluorocarbons that do not contain chlorine in the composition are also prohibited from being released into the atmosphere because chlorofluorocarbon molecules are a cause of global warming stronger than carbon dioxide.
There are a waste mixed combustion method, a submerged combustion method, a plasma method, a heating steam reaction method, and a catalyst method as a decomposition method of CFCs.
The heated steam reaction method requires a high temperature of about 1,000 ° C., but the catalyst method can decompose chlorofluorocarbon at a low temperature of 620 ° C. by using an aluminum phosphate catalyst.
Hydrolysis of CFCs produces carbon dioxide, hydrofluoric acid, and hydrochloric acid.
As a method for detoxifying these gases, a method of washing with an alkali solution is generally used. However, when slaked lime is used as an inexpensive alkaline agent, fluorite sludge is generated, and batch operation is performed. When neutralized with caustic soda for the purpose of continuous operation, calcium chloride auxiliary is required to form fluorite crystals.

一例として、特開２００２−１５３７３０号公報に紹介のように、所定のフロン分解能力を維持したフロン無害化処理装置が開発された。
これは、フロンを燃焼して得たフロン分解ガスをアルカリ水溶液で中和させて、該フロンを無害化処理する装置である。
特開２００２−１５３７３０号公報 特開平８−２１５５６６号公報 特開平2−131116号公報 特公平6−59388号公報 As an example, a freon detoxifying treatment apparatus that maintains a predetermined freon decomposing ability has been developed as introduced in Japanese Patent Laid-Open No. 2002-153730.
This is an apparatus for neutralizing chlorofluorocarbons by neutralizing chlorofluorocarbon decomposition gas obtained by burning chlorofluorocarbon with an alkaline aqueous solution.
JP 2002-153730 A JP-A-8-215566 JP-A-2-131116 Japanese Patent Publication No. 6-59388

しかしながら、塩酸とフッ酸を除去する方法としてアルカリ水溶液で洗浄するには、安価なアルカリ剤（消石灰：CaCO3)を使用すると吸収塔が蛍石（CaF2）で閉塞してしまい、苛性ソーダー（NaOH）を使用するとNaFの水溶液を得るが、NaFを結晶化するためにCaCl2を必要とする。即ち高価なNaOHとCaCl2を必要とする。
そこで本発明者は、高価なNaOHとCaCl2を多量に必要とすることなく、フロン分解ガス中のフッ酸及び塩酸を除去するために殆ど水のみで吸収を繰り返し、しかる後最少限のアルカリ（苛性ソダー）で排ガス中のフッ酸、塩酸を吸収し、フッ酸濃度を０ppm（塩酸濃度０ppm）にして大気に放出し、同時に高純度で高濃度のフッ酸、塩酸溶液を得る装置の開発を課題として本発明を完成したものである。 However, in order to remove hydrochloric acid and hydrofluoric acid with an alkaline aqueous solution, if an inexpensive alkaline agent (slaked lime: CaCO 3 ) is used, the absorption tower is clogged with fluorite (CaF 2 ), and caustic soda ( (NaOH) gives an aqueous solution of NaF, but requires CaCl2 to crystallize NaF. That is, expensive NaOH and CaCl2 are required.
Therefore, the present inventor repeats absorption with almost only water in order to remove hydrofluoric acid and hydrochloric acid in the chlorofluorocarbon decomposition gas without requiring a large amount of expensive NaOH and CaCl2, and then minimizes alkali (caustic). Soda) absorbs hydrofluoric acid and hydrochloric acid in exhaust gas, releases the hydrofluoric acid concentration to 0 ppm (hydrochloric acid concentration 0 ppm), and releases it to the atmosphere. This completes the present invention.

本発明は上記課題を解決するためになされたものでありその特徴とするところは、次の（1）〜（2）にある。
(1)、最下流段水洗浄吸収塔から最上流段水洗浄吸収塔に洗浄水を供給し且つ各段の底貯水部から上部散水部に洗浄水を循環供給しながらフロン分解ガスを最上流段水洗浄吸収塔に導入し最下流段水洗浄吸収塔から洗浄ガスとして排出すると共に、最上流段水洗浄吸収塔の底貯水部の溜水をフッ酸溶液回収側に送給する多段ガス洗浄式のフロン分解ガス無害化処理装置において、隣接段水洗浄吸収塔とは底貯水部をその液面下で互いに連通接続する洗浄水連通管を設け、最下流段水洗浄吸収塔の底貯水部に洗浄水を供給しかつ液面レベル保持機構を備えた洗浄水供給装置を設けたことを特徴とするフロン分解ガス無害化処理装置。
(2)、最下流段水洗浄吸収塔から最上流段水洗浄吸収塔に洗浄水を供給し且つ各段の底貯水部から上部散水部に洗浄水を循環供給しながらフロン分解ガスを最上流段水洗浄吸収塔に導入し最下流段水洗浄吸収塔から洗浄ガスとして排出すると共に、最上流段水洗浄吸収塔の底貯水部の溜水をフッ酸溶液回収側に送給する多段ガス洗浄式のフロン分解ガス無害化処理装置において、隣接段水洗浄吸収塔とは底貯水部をその液面下で互いに連通接続する洗浄水連通管を設け、最下流段水洗浄吸収塔の底貯水部に洗浄水を供給しかつ液面レベル保持機構を備えた洗浄水供給装置を設け、前記洗浄水供給装置にアルカリ剤を添加調整するアルカリ剤添加装置を設けたことを特徴とするフロン分解ガス無害化処理装置。 The present invention has been made to solve the above-mentioned problems, and the features thereof are the following (1) to (2).
(1) Supplying washing water from the most downstream stage water washing / absorption tower to the uppermost stage water washing / absorption tower and circulating supply of washing water from the bottom reservoir of each stage to the upper watering part, Multistage gas cleaning that is introduced into the staged water washing and absorption tower and discharged from the most downstream stage water washing and absorption tower as cleaning gas, and the water stored in the bottom reservoir of the most upstream stage water washing and absorption tower is sent to the hydrofluoric acid solution recovery side. In the CFC-decomposing detoxification treatment device, the adjacent stage water washing absorption tower is provided with a washing water communication pipe that connects the bottom water storage parts to each other under the liquid level, and the bottom water storage part of the most downstream stage water washing absorption tower A chlorofluorocarbon-decomposing gas detoxifying treatment apparatus characterized in that a rinsing water supply apparatus is provided that supplies rinsing water and has a liquid level maintaining mechanism.
(2) Supplying washing water from the most downstream stage water washing / absorption tower to the uppermost stage water washing / absorption tower and circulating supply of washing water from the bottom water storage part to the upper sprinkling part in each stage Multistage gas cleaning that is introduced into the staged water washing and absorption tower and discharged from the most downstream stage water washing and absorption tower as cleaning gas, and the water stored in the bottom reservoir of the most upstream stage water washing and absorption tower is sent to the hydrofluoric acid solution recovery side. In the CFC-decomposing detoxification treatment device, the adjacent stage water washing absorption tower is provided with a washing water communication pipe that connects the bottom water storage parts to each other under the liquid level, and the bottom water storage part of the most downstream stage water washing absorption tower A cleaning water supply device having a liquid level maintaining mechanism for supplying cleaning water is provided, and an alkaline agent addition device for adding and adjusting an alkaline agent is provided in the cleaning water supply device. Processing equipment.

本発明は、上記構成によりフロン分解ガスの無害化を、水のみで又は最少減のアルカリ薬剤を用いて達成出来る。これと同時に高純度、高濃度（1.5〜2.0 ％）のフッ酸又はフッ酸と塩酸水溶液が得られる。またこの回収したフッ酸又はフッ酸と塩酸の水溶液からは、別途設けた中和・結晶分離装置により高純度の蛍石（CaF）を製造することができるなどの優れた効果を得るものである。   The present invention can achieve detoxification of CFC-decomposed gas by using the above-described configuration using only water or a minimal amount of alkali chemicals. At the same time, high-purity and high-concentration (1.5 to 2.0%) hydrofluoric acid or hydrofluoric acid and hydrochloric acid aqueous solution are obtained. Further, from the recovered hydrofluoric acid or the aqueous solution of hydrofluoric acid and hydrochloric acid, excellent effects such as high purity fluorite (CaF) can be produced by a neutralization / crystal separation apparatus provided separately. .

本発明を実施するための最良の形態を以下に具体的に紹介する。
本発明においてフロン分解ガスの原料フロンガスは、塩素を含まないものとしてCH2FCF3を対象とし、塩素を含むものとしてCCl2F2を対象とする。本発明において、塩素を含まないフロンガスを分解する手段は、例えばＬＰＧ、ＬＮＧ、メタガスなどの可燃ガスの燃焼排ガス（6２0〜700℃）とフロンガスを混合し、これを触媒として焼酸アルミ等を用いた触媒塔に導入するものでよい。
本発明において、塩素を含むフロンガスを分解する手段は、例えば可燃ガスの燃焼排ガス（6２0〜700℃）とフロンガスを混合し、これを触媒として燐酸アルミを用いた触媒塔に導入するものでよい。
また前記効果を確実に得るための多段の水洗浄吸収塔の処理条件は、触媒筒を出たフロン分解ガスはフッ酸濃度４〜５％、ガス温度６２０〜７００℃であるが最終段の水噴射によって４０〜５０℃のフロン分解ガス温度となる。このガス７５０NＬ／分 処理する場合、各段の水洗浄吸収塔の容量を６５〜７０Ｌとし、充填材の材質をテフロンとし、最上流段の散水温度は６０〜５０℃になり、その他の水洗浄吸収塔における散水温度は５０〜４０℃の平衡温度になる。また好ましい塔頂圧力２００〜１５０mmAqとする。
各塔での循環水量は360〜400 L／hrで洗浄水供給装置から最下流段の底貯水部への給水量は100〜120／hrとすればよい。
本発明において塩酸を含むフロン分解ガスの処理において、最下流段の水洗浄吸収塔の散水pHを調整するアルカリ剤としては、苛性ソーダー、を用い、pHは6.0以下にならないようにアルカリ液を注入することによって最下流段の水洗浄吸収塔からの排出ガス中のフッ素濃度を0ppmにすることができる。排ガス中の塩酸濃度は規制値以下の0ppm である。pH6.0以下では0ppmにすることができない。また、前記洗浄水供給装置における液面レベル保持手段は、最下流段の水洗浄吸収塔から最上流段の水洗浄吸収塔及び洗浄水供給装置の給水タンクの各底貯水部をその液面下で連通管で接続する。これらの底貯水部の液面は各塔内の充填材のガス圧損だけ上流側は下がるが、相互に関連があるので、外気に液面が出ている給水タンクで水位制御をするのみで各吸収塔全部の液面制御を容易に確実に実施することができる。このため前記の給水タンクへの給水流量の設定を、フッ酸又は塩酸とフッ酸の溶液回収側に送給する機構に給水調節弁を設け、この操作と給水タンクに液面制御用のボールタップ等を設けて給水タンクのみのレベル制御を自動的に行えばよい。
つまり多段の水洗浄吸収塔における各水洗浄吸収塔下部の底貯水部の液面制御は、安定した外気に接する前記給水タンクの液面一カ所のみで行うことが最も好ましい。 The best mode for carrying out the present invention will be specifically described below.
In the present invention, the raw material freon gas of the flon decomposition gas is intended for CH 2 FCF 3 as containing no chlorine, and intended for CCl 2 F 2 as containing chlorine. In the present invention, the means for decomposing chlorine-free chlorofluorocarbon gas is, for example, a mixture of flammable exhaust gas (620 ° C. to 700 ° C.) of flammable gas such as LPG, LNG, metagas, etc., and using baked aluminum as a catalyst. May be introduced into the catalyst tower.
In the present invention, the means for decomposing chlorine-containing chlorofluorocarbon gas may be, for example, a mixture of flammable combustion gas (620 to 700 ° C.) and chlorofluorocarbon gas and introducing it into a catalyst tower using aluminum phosphate as a catalyst.
The processing conditions of the multi-stage water-washing absorption tower for ensuring the above-mentioned effect are as follows. The chlorofluorocarbon decomposition gas exiting the catalyst cylinder has a hydrofluoric acid concentration of 4 to 5% and a gas temperature of 620 to 700 ° C. The chlorofluorocarbon decomposition gas temperature is 40 to 50 ° C. by injection. When treating this gas at 750 NL / min, the capacity of the water-washing absorption tower of each stage is 65-70 L, the material of the filler is Teflon, the watering temperature of the uppermost stream is 60-50 ° C., and other water washing The watering temperature in the absorption tower is an equilibrium temperature of 50 to 40 ° C. Moreover, it is set as preferable column top pressure 200-150 mmAq.
The amount of circulating water in each tower may be 360 to 400 L / hr, and the amount of water supplied from the washing water supply device to the bottom reservoir of the most downstream stage may be 100 to 120 / hr.
In the treatment of CFC-decomposing gas containing hydrochloric acid in the present invention, caustic soda is used as an alkaline agent for adjusting the sprinkling pH of the water washing absorption tower at the most downstream stage, and an alkaline liquid is injected so that the pH does not become 6.0 or lower. By doing so, the fluorine concentration in the exhaust gas from the water washing absorption tower at the most downstream stage can be reduced to 0 ppm. The concentration of hydrochloric acid in the exhaust gas is 0 ppm below the regulation value. It cannot be reduced to 0ppm below pH 6.0. Further, the liquid level holding means in the washing water supply device includes the bottom water storage part of the water washing absorption tower of the most upstream stage and the water tank of the washing water supply apparatus from the water washing absorption tower of the most downstream stage below the liquid level. Connect with a communication pipe. The liquid level of these bottom reservoirs is lowered on the upstream side by the gas pressure loss of the packing material in each tower, but since they are related to each other, each level can be controlled only by controlling the water level in the water supply tank where the liquid level is exposed to the outside air. Liquid level control of the entire absorption tower can be carried out easily and reliably. For this reason, a water supply control valve is provided in the mechanism for supplying the water supply flow rate to the water supply tank to the solution recovery side of hydrofluoric acid or hydrochloric acid and hydrofluoric acid, and a ball tap for controlling the liquid level is provided in this operation and the water tank. And the level control of only the water supply tank may be automatically performed.
In other words, it is most preferable that the liquid level control of the bottom water storage section at the lower part of each water washing / absorbing tower in the multistage water washing / absorbing tower is performed only at one liquid level of the water supply tank in contact with the stable outside air.

本実施例は塩酸を含むフロン分解ガスの無害化処理装置を紹介するものである。
図１に示す装置例において、原料フロンとして塩素を含むR12,R22を用い、フロン分解ガス生成装置は、LPGガス燃焼炉１からの可燃ガスの燃焼排ガス（650℃）に排ガス管1-2で前記原料フロンガスR12,又はR22を３kg/h注入混合し、これを触媒として燐酸アルミを用いた触媒塔２に導入して温度６２０℃、後述のようにフッ酸濃度４％のフロン分解ガスを750 NL/分を得る。
塩素を含む冷媒（例R12,R22）は触媒塔２で次の加水分解をして塩酸（HCl）とフッ酸（HF）を生成する。
R12： CCl2F2＋2H2O＝CO2＋2HCl＋2HF
R22： CHClF2＋2H2O＝CO2＋HCl＋2HF
前記フロン分解ガスの水分を除く成分を表1（単位％）に示す。 This embodiment introduces a detoxification treatment apparatus for chlorodecomposition gas containing hydrochloric acid.
In the apparatus example shown in FIG. 1, R 12 and R 22 containing chlorine are used as the raw material flon, and the CFC decomposition gas generator generates the flue gas pipe 1− from the LPG gas combustion furnace 1 as the combustible gas combustion exhaust gas (650 ° C.). The raw material chlorofluorocarbon gas R 12 or R 22 is injected and mixed at 2 kg and introduced into the catalyst tower 2 using aluminum phosphate as a catalyst. The temperature is 620 ° C. and chlorofluorocarbon concentration is 4% as described later. Obtain 750 NL / min of cracked gas.
A refrigerant containing chlorine (eg, R 12 and R 22 ) undergoes the following hydrolysis in the catalyst tower 2 to generate hydrochloric acid (HCl) and hydrofluoric acid (HF).
R 12 : CCl 2 F 2 + 2H 2 O = CO 2 + 2HCl + 2HF
R 22 : CHClF 2 + 2H 2 O = CO 2 + HCl + 2HF
Table 1 (unit%) shows the components of the CFC decomposition gas excluding moisture.

Figure 2006320889
（注1）35℃〜40℃ に於ける飽和水蒸気を含む
第１〜第５水洗浄吸収塔７a〜７eは、触媒塔２からの前記フロン分解ガスを最上流の第１水洗浄吸収塔７aの上部に導入し最下流段の第５水洗浄吸収塔7eの上部から排出する。第１水洗浄吸収塔７aからの排ガスはその胴部から第２水洗浄吸収塔７bの胴部に排ガス管16で供給する。第２〜第５水洗浄吸収塔７b〜７eの各塔間の排ガスは、隣接する上流段の水洗浄吸収塔の上部から下流段の水洗浄吸収塔の胴部に排ガス管17で供給する。
第５水洗浄吸収塔７eの洗浄排ガス15は排ガス管18から大気放散する。
また第１〜第５水洗浄吸収塔７a〜７eは、底貯水部から上部散水部6に洗浄水を循環供給管３とポンプ４で供給し、隣接塔とは底貯水部11を互いに洗浄水連通管５で接続する。散水温度は水蒸気とその他ガスの分圧から平衡する温度になる。即ち第１水洗浄吸収塔７aは５０〜６０℃、第２〜第５水洗浄吸収塔７b〜７eは３５〜５０℃になる。14は充填材層である。
最下流段の第５水洗浄吸収塔７eは、洗浄水供給装置により底貯水部11に洗浄水を供給する。
洗浄水供給装置は、給水タンク9と液面レベル保持機構8とアルカリ剤を添加調整するアルカリ剤添加装置10とを備えてある。
５段の水洗浄吸収塔の吸収液（循環液）の液面制御をする液面レベル保持機構8は、第５水洗浄吸収塔7eに連通させた給水タンク9の外気に接する液面の１カ所にボールタップ8aを設けこれに連動する給水弁8bを設けてなる。
アルカリ剤添加装置10は、フロン分解ガスに塩酸が含まれている場合のみ稼動させる。
最上流段の第１水洗浄吸収塔7aは、底貯水部11の溜水をフッ酸又は塩酸とフッ酸溶液の回収側に送給する回収機構12、13を付設してある。回収機構は流量設定120Ｌ／ｈの流量調節弁12と回収管13とからなる。
Figure 2006320889
 (Note 1) The first to fifth water washing / absorbing towers 7a to 7e containing saturated water vapor at 35 ° C. to 40 ° C. are the first water washing / absorbing tower 7a which is the most upstream of the CFC decomposition gas from the catalyst tower 2. And is discharged from the upper part of the fifth water washing absorption tower 7e at the most downstream stage. The exhaust gas from the first water washing / absorbing tower 7a is supplied from its trunk to the trunk of the second water washing / absorbing tower 7b through the exhaust pipe 16. The exhaust gas between each of the second to fifth water washing absorption towers 7b to 7e is supplied from the upper part of the adjacent upstream water washing absorption tower to the trunk of the downstream water washing absorption tower through the exhaust pipe 17.
The cleaning exhaust gas 15 of the fifth water cleaning absorption tower 7e is diffused into the atmosphere from the exhaust gas pipe 18.
In addition, the first to fifth water washing absorption towers 7a to 7e supply washing water from the bottom water storage section to the upper watering section 6 by the circulation supply pipe 3 and the pump 4, and the adjacent towers wash the bottom water storage section 11 with each other. Connect with the communication pipe 5. The sprinkling temperature is a temperature that equilibrates from the partial pressure of water vapor and other gases. That is, the first water washing absorption tower 7a has a temperature of 50 to 60 ° C, and the second to fifth water washing absorption towers 7b to 7e have a temperature of 35 to 50 ° C. 14 is a filler layer.
The fifth water washing / absorbing tower 7e at the most downstream stage supplies washing water to the bottom water reservoir 11 by a washing water supply device.
The cleaning water supply device includes a water supply tank 9, a liquid level holding mechanism 8, and an alkaline agent addition device 10 for adding and adjusting an alkaline agent.
The liquid level maintaining mechanism 8 for controlling the liquid level of the absorption liquid (circulating liquid) of the five-stage water washing absorption tower is one of the liquid levels in contact with the outside air of the water supply tank 9 communicated with the fifth water washing absorption tower 7e. A ball tap 8a is provided at the place, and a water supply valve 8b linked to the ball tap 8a is provided.
The alkaline agent addition apparatus 10 is operated only when hydrochloric acid is contained in the chlorofluorocarbon decomposition gas.
The first water-washing absorption tower 7a in the uppermost stream stage is provided with recovery mechanisms 12 and 13 for feeding the water stored in the bottom water storage part 11 to the recovery side of hydrofluoric acid or hydrochloric acid and hydrofluoric acid solution. The recovery mechanism comprises a flow rate control valve 12 and a recovery pipe 13 with a flow rate setting of 120 L / h.

次にこの装置例と操業条件例を前提に具体的な無害化処理工程を詳述する。
１）フロン分解ガスを多段の水洗浄吸収塔で水洗浄無害化
前記フロン分解ガスを大気に放出するために前記５段の第１〜第５水洗浄吸収塔７a〜７eでフッ酸と塩酸を完全に除去する。
通常、塩素を含むフロンの前記フロン分解ガスは、塩酸、フッ酸をアルカリ液で洗浄すればよいが安価なアルカリ剤（消石灰：CaCO3)を使用すると水洗浄吸収塔の充填部が蛍石（CaF2）で閉塞する。苛性ソダー（NaOH）を使用するとNaFの水溶液を得るが、NaFを結晶化するためにCaClを必要とする。即ち高価なNaOHとCaClを必要とする。
そこでフロン分解ガス中の塩酸、フッ酸を完全に除去するために最少限の苛性ソダーで中和するためには、塩酸、フッ酸を含有するフロン分解ガスを先ず水で前記５段の水洗浄吸収塔7a〜7eで順次洗浄循環水に吸収して排気中の塩酸、フッ酸濃度をさげ最下流段の第５水洗浄吸収塔で洗浄循環水のpHを6.0以上の微酸性に維持して洗浄することにより洗浄排ガス15中のフッ酸濃度を０ppmにすることができる。
フッ酸、塩酸を含有したフロン分解ガスを5段の水洗浄吸収塔で水洗浄すると強酸である塩酸は優先的に水に溶けるが、フッ酸は液相に移れず 最下流段の第５水洗浄吸収塔7eからフロン分解ガス中に微量検出される。
最下流段の第５水洗浄吸収塔7eの循環液のpHが例えば5.8のとき20 ppmを検出した。
最下流段の第５水洗浄吸収塔7eにアルカリ剤添加装置10から給水タンク9を介して苛性ソーダーNaOHを注入してpHを6.0にすればフロン分解ガス中にフッ酸は検出されない。当然 塩酸も検収されない。
最下流段の第５水洗浄吸収塔7eの循環液に苛性ソーダーNaOHを加えるとフッ酸と次の中和反応（HF＋NaOH＝NaF＋H2O）がおこる。
第５水洗浄吸収塔7eで生成したNaFは水に対する溶解度が高くNa+イオン、F−イオンの状態でその上流の第４水洗浄吸収塔7dに送られる。
第５洗浄吸収塔7dの循環液では、HCl＋NaF→HF＋NaClの置換がおこる。
この第１〜第５水洗浄吸収塔で1.5〜2.0 ％の塩酸、フッ酸水溶液が製造される。この水溶液にここで使用した苛性ソーダー（NaOH）に等モルの食塩（NaCl）が含まれることになる。
３）吸収液のPHとフロン分解ガス中のフッ酸、塩酸濃度の関係
実験の結果から最終段（最下流）の水洗浄吸収塔7eの洗浄循環水のpHを６以上にすれば排気中の塩酸とフッ酸の濃度を０ ppmに出来る。pHを６以上に保つためにアルカリ剤としてカセイソーダー（NaOH）等を用いる。
第５水洗浄吸収塔7eでの洗浄循環水のpHとフロン分解ガス中のフッ酸、塩酸濃度は表2に示す。 Next, specific detoxification processing steps will be described in detail on the premise of this apparatus example and operation condition example.
1) Detoxification of CFC-resolved gas with multi-stage water-washing / absorbing towers In order to release the CFC-decomposed gas into the atmosphere, hydrofluoric acid and hydrochloric acid are used in the five-stage first to fifth water-washing / absorbing towers 7a to 7e. Remove completely.
Normally, the chlorofluorocarbon-containing chlorofluorocarbon decomposition gas should be washed with hydrochloric acid and hydrofluoric acid with an alkaline solution. However, when an inexpensive alkaline agent (slaked lime: CaCO 3 ) is used, the packed part of the water washing absorption tower is fluorite ( Block with CaF 2 ). When caustic soda (NaOH) is used, an aqueous solution of NaF is obtained, but CaCl is required to crystallize NaF. That is, expensive NaOH and CaCl are required.
Therefore, in order to completely remove hydrochloric acid and hydrofluoric acid in the chlorofluorocarbon cracking gas, neutralization with the minimum amount of caustic soda is performed. First, the chlorofluorocarbon cracking gas containing hydrochloric acid and hydrofluoric acid is washed with water in the above five stages. The absorption water in the washing towers 7a to 7e is absorbed into the wash circulating water in order to reduce the concentration of hydrochloric acid and hydrofluoric acid in the exhaust gas, and the pH of the wash circulating water is maintained at a slightly acidic value of 6.0 or more in the fifth water wash absorption tower at the most downstream stage. By cleaning, the concentration of hydrofluoric acid in the cleaning exhaust gas 15 can be reduced to 0 ppm.
When hydrocracking gas containing hydrofluoric acid and hydrochloric acid is washed with water in a 5-stage water-washing absorption tower, hydrochloric acid, which is a strong acid, is preferentially dissolved in water, but hydrofluoric acid cannot be transferred to the liquid phase and is the fifth most downstream water. A trace amount is detected in the chlorofluorocarbon decomposition gas from the cleaning absorption tower 7e.
For example, 20 ppm was detected when the pH of the circulating liquid in the fifth water washing absorption tower 7e in the most downstream stage was 5.8.
If caustic soda NaOH is injected from the alkaline agent addition device 10 through the water supply tank 9 to the fifth water washing absorption tower 7e in the most downstream stage to adjust the pH to 6.0, hydrofluoric acid is not detected in the chlorofluorocarbon decomposition gas. Naturally, hydrochloric acid is not accepted.
When caustic soda NaOH is added to the circulating liquid of the fifth water washing absorption tower 7e at the most downstream stage, hydrofluoric acid and the next neutralization reaction (HF + NaOH = NaF + H 2 O) occur.
NaF produced in the fifth water washing / absorbing tower 7e has a high solubility in water and is sent to the fourth water washing / absorbing tower 7d upstream in the state of Na + ions and F − ions.
In the circulating liquid of the fifth washing absorption tower 7d, substitution of HCl + NaF → HF + NaCl occurs.
In the first to fifth water-washing absorption towers, 1.5 to 2.0% hydrochloric acid and hydrofluoric acid aqueous solution are produced. This aqueous solution contains equimolar sodium chloride (NaCl) in the caustic soda (NaOH) used here.
3) From the results of the experiment on the relationship between the pH of the absorption liquid and the concentration of hydrofluoric acid and hydrochloric acid in the CFC decomposition gas, if the pH of the wash circulating water in the final stage (the most downstream) water wash absorption tower 7e is 6 or more, The concentration of hydrochloric acid and hydrofluoric acid can be reduced to 0 ppm. In order to maintain the pH at 6 or more, caustic soda (NaOH) or the like is used as an alkaline agent.
Table 2 shows the pH of the circulating circulating water in the fifth water cleaning absorption tower 7e and the concentrations of hydrofluoric acid and hydrochloric acid in the chlorofluorocarbon decomposition gas.

Figure 2006320889
４）多段吸収の効率を上げることによって アルカリ剤（NaOH）の実機に於ける使用量は減少するが５段の水洗浄吸収塔の最下流段の水洗浄吸収塔7eにおけるNaOH(苛性ソーダー)注入量は下記のとおり。
＜冷媒フロンR22を触媒法により2.78 kg/h 処理する場合＞
a. フロン分解ガスの流量：745 NL/分（ドライベース％）
b. 吸収液の補給水：２Ｌ/分
c. フロン分解ガスの成分（ドライベース）は前述の表１に示してある。
d. NaOH(苛性ソーダー)注入量は毎時１グラム以上を投入すればpHを6.0以上を維持出来る。即ちフロン分解ガス中のフッ酸、塩酸濃度を０ppmを達成できる。
５）NaOH(苛性ソーダー)注入量
具体的注入方式としてはアルカリ剤添加装置10から給水タンク９の給水中に１規定のNaOH溶液を毎時25 CCを点滴し、第５水洗浄吸収塔7eに供給する。
これにより触媒塔を出た前記フロン分解ガスは、塩酸、フッ酸を散水洗浄吸収液に吸収させて1.5〜2％の塩酸、フッ酸の水溶液を得る。
このとき各水洗浄吸収塔7a〜7eの洗浄循環水の洗浄循環水のpH値（水素イオン濃度）は、表３の通りであった。
Figure 2006320889
 4) Increasing the efficiency of multistage absorption reduces the amount of alkali agent (NaOH) used in the actual machine, but injects NaOH (caustic soda) into the water wash absorption tower 7e at the most downstream stage of the 5 stage water wash absorption tower. The amount is as follows.
<When treating refrigerant CFC R22 by catalytic method 2.78 kg / h>
a. Flow rate of CFC decomposition gas: 745 NL / min (dry base%)
b. Replenishment water for absorbent: 2L / min
c. Components of CFC decomposition gas (dry base) are shown in Table 1 above.
d. The pH of NaOH (caustic soda) can be maintained at 6.0 or higher by adding more than 1 gram per hour. That is, the concentration of hydrofluoric acid and hydrochloric acid in the chlorodecomposition gas can be achieved to 0 ppm.
5) NaOH (caustic soda) injection amount As a specific injection method, 1 CC of NaOH solution is instilled into the water supply tank 9 from the alkaline agent addition device 10 at a rate of 25 CC per hour and supplied to the fifth water washing absorption tower 7e. To do.
As a result, the chlorofluorocarbon-decomposing gas exiting the catalyst tower absorbs hydrochloric acid and hydrofluoric acid in the sprinkling washing absorbent to obtain an aqueous solution of 1.5 to 2% hydrochloric acid and hydrofluoric acid.
At this time, the pH value (hydrogen ion concentration) of the washing circulating water in each of the water washing absorption towers 7a to 7e was as shown in Table 3.

Figure 2006320889
Figure 2006320889

本発明は、上記効果の通りフロン分解ガスの無害化を、水のみで又は最少減のアルカリ薬剤を用いて達成出来ると同時に高純度、高濃度のフッ酸又はフッ酸と塩酸水溶液が得られる。またこの回収したフッ酸又はフッ酸と塩酸の水溶液からは、別途設けた中和・結晶分離装置により高純度の蛍石（CaF）を製造することができるものであり、蛍石は冶金学でいうところのフラックスとして使用したり冷媒の原料など多くの利用分野が存在する。   As described above, the present invention can achieve detoxification of CFC-decomposed gas using only water or a minimal amount of alkali chemicals, and at the same time, high-purity and high-concentration hydrofluoric acid or hydrofluoric acid and hydrochloric acid aqueous solution can be obtained. From this recovered hydrofluoric acid or aqueous solution of hydrofluoric acid and hydrochloric acid, high-purity fluorite (CaF) can be produced by a separate neutralization / crystal separation device. There are many fields of use such as fluxes and raw materials for refrigerants.

本発明の装置例を示す説明図であるIt is explanatory drawing which shows the example of an apparatus of this invention

符号の説明Explanation of symbols

１ フロン分解ガス生成装置のLPGガス燃焼炉
２ フロン分解ガス生成装置の触媒塔
1-2 排ガス管
３ 循環供給
４ ポンプ
７a〜７e 第１〜第５水洗浄吸収塔
8 液面レベル保持機構
8a ボールタップ
8b 給水弁
9 給水タンク
10 アルカリ剤添加装置
11 底貯水部
12 流量調節弁
13 回収管
14 充填材
15 洗浄排ガス管
17,16 ,18 排ガス管
1 LPG gas combustion furnace of CFC decomposition gas generator 2 Catalyst tower of CFC decomposition gas generator
1-2 Exhaust gas pipe
3 Circulating supply 4 Pumps 7a to 7e First to fifth water washing absorption towers
8 Liquid level holding mechanism
8a Ball tap
8b Water supply valve
9 Water tank
10 Alkaline agent addition equipment
11 Bottom water reservoir
12 Flow control valve
13 Collection pipe
14 Filler
15 Cleaning exhaust pipe
17,16,18 Exhaust pipe

Claims (2)

最下流段水洗浄吸収塔から最上流段水洗浄吸収塔に洗浄水を供給し且つ各段の底貯水部から上部散水部に洗浄水を循環供給しながらフロン分解ガスを最上流段水洗浄吸収塔に導入し最下流段水洗浄吸収塔から洗浄ガスとして排出すると共に、最上流段水洗浄吸収塔の底貯水部の溜水をフッ酸溶液回収側に送給する多段ガス洗浄式のフロン分解ガス無害化処理装置において、隣接段水洗浄吸収塔とは底貯水部をその液面下で互いに連通接続する洗浄水連通管を設け、最下流段水洗浄吸収塔の底貯水部に洗浄水を供給しかつ液面レベル保持機構を備えた洗浄水供給装置を設けたことを特徴とするフロン分解ガス無害化処理装置。 Supplying washing water from the most downstream stage water washing absorption tower to the uppermost stage water washing absorption tower and circulating supply of washing water from the bottom water storage part of each stage to the upper sprinkling part, absorbs the CFC decomposition gas to the uppermost stage water washing absorption Multistage gas cleaning type chlorofluorocarbon decomposition system that introduces into the tower and discharges it from the most downstream stage water washing and absorption tower as cleaning gas, and supplies the water stored in the bottom reservoir of the most upstream stage water washing and absorption tower to the hydrofluoric acid solution recovery side In the gas detoxification treatment equipment, the adjacent stage water washing absorption tower is provided with a washing water communication pipe that connects the bottom water storage parts to each other under the liquid level, and the washing water is supplied to the bottom water storage part of the most downstream stage water washing absorption tower. A fluorocarbon decomposition gas detoxification treatment apparatus provided with a cleaning water supply device that supplies and has a liquid level holding mechanism. 最下流段水洗浄吸収塔から最上流段水洗浄吸収塔に洗浄水を供給し且つ各段の底貯水部から上部散水部に洗浄水を循環供給しながらフロン分解ガスを最上流段水洗浄吸収塔に導入し最下流段水洗浄吸収塔から洗浄ガスとして排出すると共に、最上流段水洗浄吸収塔の底貯水部の溜水をフッ酸溶液回収側に送給する多段ガス洗浄式のフロン分解ガス無害化処理装置において、隣接段水洗浄吸収塔とは底貯水部をその液面下で互いに連通接続する洗浄水連通管を設け、最下流段水洗浄吸収塔の底貯水部に洗浄水を供給しかつ液面レベル保持機構を備えた洗浄水供給装置を設け、前記洗浄水供給装置にアルカリ剤を添加調整するアルカリ剤添加装置を設けたことを特徴とするフロン分解ガス無害化処理装置。
Supplying washing water from the most downstream stage water washing absorption tower to the uppermost stage water washing absorption tower and circulating supply of washing water from the bottom water storage part of each stage to the upper sprinkling part, absorbs the CFC decomposition gas to the uppermost stage water washing absorption Multistage gas cleaning type chlorofluorocarbon decomposition system that introduces into the tower and discharges it from the most downstream stage water washing and absorption tower as cleaning gas, and supplies the water stored in the bottom reservoir of the most upstream stage water washing and absorption tower to the hydrofluoric acid solution recovery side In the gas detoxification treatment equipment, the adjacent stage water washing absorption tower is provided with a washing water communication pipe that connects the bottom water storage parts to each other under the liquid level, and the washing water is supplied to the bottom water storage part of the most downstream stage water washing absorption tower. A fluorocarbon cracking gas detoxification treatment apparatus characterized in that a cleaning water supply device that supplies and has a liquid level holding mechanism is provided, and an alkaline agent addition device that adds and adjusts an alkaline agent is provided in the cleaning water supply device.
JP2006039208A 2005-04-20 2006-02-16 Apparatus for rendering chloroflurocarbon decomposition gas harmless Pending JP2006320889A (en)

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101601957A (en) * 2008-12-23 2009-12-16 匡优新 A kind of recycling EGR of acid waste gas of improvement
KR20220134066A (en) * 2021-03-26 2022-10-05 엽정화 Hazardous Exhaust Gas Wet Purification device

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101601957A (en) * 2008-12-23 2009-12-16 匡优新 A kind of recycling EGR of acid waste gas of improvement
KR20220134066A (en) * 2021-03-26 2022-10-05 엽정화 Hazardous Exhaust Gas Wet Purification device
KR102589114B1 (en) 2021-03-26 2023-10-16 엽정화 Hazardous Exhaust Gas Wet Purification device

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