JP2013150981A - Heat-cleaning apparatus for contaminated soil - Google Patents

Heat-cleaning apparatus for contaminated soil Download PDF

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JP2013150981A
JP2013150981A JP2013044950A JP2013044950A JP2013150981A JP 2013150981 A JP2013150981 A JP 2013150981A JP 2013044950 A JP2013044950 A JP 2013044950A JP 2013044950 A JP2013044950 A JP 2013044950A JP 2013150981 A JP2013150981 A JP 2013150981A
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contaminated soil
kiln
cylinder
preheating
heat
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Hideto Horai
秀人 蓬莱
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Nikko Co Ltd
日工株式会社
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PROBLEM TO BE SOLVED: To provide a heat-cleaning apparatus for contaminated soil that can perform ideal heat-cleaning treatment of contaminated soil while saving energy.SOLUTION: A preheating kiln 12 for heating soil before cleaning with the potential heat of exhaust gas exhausted from a heating treatment kiln 1 for performing heat-cleaning treatment of contaminated soil is provided downstream of exhaust gas from the heating treatment kiln 1. The contaminated soil before cleaning is supplied to the preheating kiln 12 and heated with the potential heat of exhaust gas from the heating treatment kiln 1 to perform pretreatment for reducing the water content of the contaminated soil, and then the contaminated soil reduced in the water content is supplied to the heating treatment kiln 1 to perform heat-cleaning treatment.

Description

本発明は、軽質油、重質油、VOC(揮発性有機化合物)、ダイオキシン、PCBなどの汚染物質を含んだ汚染土壌を加熱して浄化処理する装置に関する。   The present invention relates to an apparatus for heating and purifying contaminated soil containing pollutants such as light oil, heavy oil, VOC (volatile organic compound), dioxin, and PCB.
産業活動に伴って各事業所の敷地内やその周辺地域の土壌が油等の汚染物質の廃液によって汚染されていると、この汚染土壌を浄化する必要がある。汚染土壌を浄化処理する一方法として、加熱用ロータリーキルンを利用して土壌中にしみ込んでいる揮発性有機化合物を揮発・分解させることで浄化処理する方法がある。特許文献1記載の汚染土壌浄化処理装置では、内周壁に耐火材を施工した加熱処理キルンを設け、該加熱処理キルンでダイオキシンを含む汚染土壌を高温で加熱して土壌中のダイオキシンを揮発、熱分解させてガス化し、このガス化させたダイオキシンを酸化分解炉にて高温ガス雰囲気中にさらすことで加熱分解し、また酸化分解炉を通過した排ガスを冷却塔にて急冷させてダイオキシンの再析出を抑えることで、ダイオキシン等を含む汚染土壌をも浄化処理できるようにしている。
特開2008−62168号公報
If the soil in the premises of each business site or the surrounding area is contaminated with waste liquids of pollutants such as oil due to industrial activities, it is necessary to purify the contaminated soil. As one method of purifying contaminated soil, there is a method of purifying by volatilizing and decomposing volatile organic compounds that have soaked in the soil using a rotary kiln for heating. In the contaminated soil purification treatment apparatus described in Patent Document 1, a heat treatment kiln having a refractory material is provided on the inner peripheral wall, and the contaminated soil containing dioxin is heated at a high temperature in the heat treatment kiln to volatilize dioxins in the soil. The gasified dioxin is decomposed by heating and exposed to high-temperature gas atmosphere in an oxidative decomposition furnace, and the exhaust gas that has passed through the oxidative decomposition furnace is quenched in a cooling tower to reprecipitate dioxin. By suppressing the above, it is possible to purify contaminated soil containing dioxins and the like.
JP 2008-62168 A
しかしながら、上記のように高温で加熱する浄化処理装置においては、熱源として多量の化石燃料を使用することとなるため、燃料費の削減や二酸化炭素の発生量の抑制といった省エネルギー化をどのように工夫するかが問題となる。   However, in the purification processing apparatus that heats at a high temperature as described above, a large amount of fossil fuel is used as a heat source, so how to conserve energy such as reduction of fuel cost and suppression of carbon dioxide generation amount. It will be a problem.
本発明は上記の点に鑑み、省エネルギー化を図りながら汚染土壌を好適に加熱浄化処理できる汚染土壌の加熱浄化装置を提供することを課題とする。   This invention makes it a subject to provide the heating purification apparatus of the contaminated soil which can heat-purify the contaminated soil suitably, aiming at energy saving in view of said point.
上記の課題を解決するために、本発明者は鋭意検討を重ねた結果、汚染土壌を加熱することにより油等の有害物質の蒸気圧を高めて脱離することが浄化の基本原理であるがために、汚染土壌の含水比の影響が燃料消費量を大きく左右し、前もって汚染土壌の含水比を小さくすることが省エネルギー化の要となること、また汚染土壌を安定的に浄化処理装置に定量供給することが品質(浄化レベル)を安定させるために不可欠であり、そのために汚染土壌をホッパフィーダから定量切り出し可能な性状まで前処理を行っており、礫や異物の除去並びに粘土質やシルト質の高含水比の軟弱土壌には生石灰の添加等による含水比の低減や土粒子の増粒を行うなど、前処理に大きな労力と時間を要しているのが現状であり、この前処理を簡略化することで省エネルギー化が図れること、また汚染土壌を加熱する加熱用ロータリーキルンから導出される高温排ガスを冷却塔にて急冷させているが、この排ガス保有熱を有効に利用すれば省エネルギー化が図れること、等に着眼して本発明に至ったものである。   In order to solve the above problems, the present inventor has made extensive studies, and as a result, the basic principle of purification is to desorb the toxic substances such as oil by increasing the vapor pressure by heating the contaminated soil. Therefore, the influence of the moisture content of the contaminated soil has a great influence on the fuel consumption, and it is necessary to reduce the moisture content of the contaminated soil in advance to save energy. Supplying is essential to stabilize the quality (purification level). For this reason, contaminated soil is pretreated from the hopper feeder to a state where it can be cut out quantitatively, removing gravel and foreign materials, as well as clay and silt. Currently, it takes a lot of labor and time for pre-treatment, such as reducing the water content by adding quick lime and increasing the size of soil particles. To simplify Can save energy, and the high-temperature exhaust gas derived from the heating rotary kiln that heats contaminated soil is rapidly cooled in the cooling tower, but energy can be saved if this exhaust gas heat is used effectively, etc. Thus, the present invention has been achieved.
即ち、本発明の請求項1記載の汚染土壌の加熱浄化装置にあっては、回転自在に傾斜支持したドラム内でバーナから送り込む熱風と汚染土壌とを接触させて汚染土壌を加熱浄化処理する加熱処理キルンと、該加熱処理キルンの排出側には排ガス中の汚染物質を加熱分解させる酸化分解炉と、該酸化分解炉から排出される排ガスの保有熱によって浄化前の土壌を加熱する間接加熱方式の予備加熱装置と、該予備加熱装置から排出される汚染土壌を前記加熱処理キルンへと供給する供給手段とを備え、前記間接加熱方式の予備加熱装置に連結した加熱処理キルンから供給される高温排ガスを排気する排気ダクトの下流には熱交換器と、排ガス温度を低下させる冷却塔と、バグフィルター集塵機とを備える一方、予備加熱装置に連結した汚染土壌の加熱によって発生する水蒸気や揮発性有害ガスを含む低温のガスを排気する排気ダクトの下流にはバグフィルター集塵機を備え、該バグフィルター集塵機の排気ダクトを前記熱交換器内へと導き、前記高温の排ガスと熱交換させて昇温した揮発性有害ガスを含むガスを加熱処理キルンに備えたバーナの燃焼用空気として供給する構成としたことを特徴としている。   That is, in the heating and purifying apparatus for contaminated soil according to claim 1 of the present invention, heating is performed by heating and purifying the contaminated soil by bringing the hot air fed from the burner into contact with the contaminated soil in a drum that is rotatably and tiltably supported. A treatment kiln, an oxidation decomposition furnace that thermally decomposes pollutants in the exhaust gas on the discharge side of the heat treatment kiln, and an indirect heating method that heats the soil before purification by the retained heat of the exhaust gas discharged from the oxidation decomposition furnace High temperature supplied from the heat treatment kiln connected to the preheating device of the indirect heating system, and a supply means for supplying the contaminated soil discharged from the preheating device to the heat treatment kiln. A heat exchanger, a cooling tower that lowers the exhaust gas temperature, and a bag filter dust collector are provided downstream of the exhaust duct that exhausts the exhaust gas. A bag filter dust collector is provided downstream of the exhaust duct for exhausting low temperature gas including water vapor and volatile harmful gas generated by heat, the exhaust duct of the bag filter dust collector is led into the heat exchanger, and the high temperature It is characterized in that a gas containing volatile harmful gas heated by exchanging heat with exhaust gas is supplied as combustion air for a burner provided in the heat treatment kiln.
また、請求項2記載の汚染土壌の加熱浄化装置にあっては、前記予備加熱装置は、回転自在に傾斜支持した内筒と、該内筒を覆う外筒とから成る二重筒構造とし、内筒内に汚染土壌を供給すると共に、外筒内に加熱処理キルンの排ガスを通過させる構成とした間接加熱方式の予備加熱キルンとしたことを特徴としている。   Further, in the heating and purifying apparatus for contaminated soil according to claim 2, the preheating apparatus has a double cylinder structure including an inner cylinder that is rotatably supported to be inclined and an outer cylinder that covers the inner cylinder, It is characterized by being a preheating kiln of an indirect heating system in which contaminated soil is supplied into the inner cylinder and the exhaust gas of the heat treatment kiln is passed through the outer cylinder.
また、請求項3記載の汚染土壌の加熱浄化装置にあっては、前記予備加熱キルンの内筒の排出端には格子状円筒体を連結し、該格子状円筒体の目開きを通過した汚染土壌は加熱処理キルンに供給し、目開きを通過しなかった塊状物は回収する構成としたことを特徴としている。   Moreover, in the heating and purifying apparatus for contaminated soil according to claim 3, a contamination in which a lattice-shaped cylindrical body is connected to the discharge end of the inner cylinder of the preheating kiln, and passes through the openings of the lattice-shaped cylindrical body. The soil is supplied to the heat treatment kiln, and the lump that has not passed through the openings is collected.
また、請求項4記載の汚染土壌の加熱浄化装置にあっては、前記予備加熱キルンの内筒内に生石灰を投入する投入手段を設けたことを特徴としている。   According to a fourth aspect of the present invention, there is provided an apparatus for heating and purifying contaminated soil, characterized in that a charging means for charging quick lime into an inner cylinder of the preheating kiln is provided.
本発明に係る請求項1記載の汚染土壌の加熱浄化装置によれば、回転自在に傾斜支持したドラム内でバーナから送り込む熱風と汚染土壌とを接触させて汚染土壌を加熱浄化処理する加熱処理キルンと、該加熱処理キルンの排出側には排ガス中の汚染物質を加熱分解させる酸化分解炉と、該酸化分解炉から排出される排ガスの保有熱によって浄化前の土壌を加熱する間接加熱方式の予備加熱装置と、該予備加熱装置から排出される汚染土壌を前記加熱処理キルンへと供給する供給手段とを備え、前記間接加熱方式の予備加熱装置に連結した加熱処理キルンから供給される高温排ガスを排気する排気ダクトの下流には熱交換器と、排ガス温度を低下させる冷却塔と、バグフィルター集塵機とを備える一方、予備加熱装置に連結した汚染土壌の加熱によって発生する水蒸気や揮発性有害ガスを含む低温のガスを排気する排気ダクトの下流にはバグフィルター集塵機を備え、該バグフィルター集塵機の排気ダクトを前記熱交換器内へと導き、前記高温の排ガスと熱交換させて昇温した揮発性有害ガスを含むガスを加熱処理キルンに備えたバーナの燃焼用空気として供給する構成としたので、加熱処理キルンの排ガス保有熱を利用して浄化前の汚染土壌の含水比を低減することで土壌浄化に要する燃料費の削減や二酸化炭素の発生量の抑制といった省エネルギー化を図ることができる。また、予備加熱装置にて汚染土壌の含水比を低減できるので、従来のような加熱処理キルンへの投入前の汚染土壌の含水比調整などの前処理を不要とすることもできる。更には、バーナに供給する燃焼用空気の温度を高くすることでバーナの燃料費の削減が図れる。また、予備加熱装置から排出される水蒸気や揮発性有害ガスを含むガスを燃焼用空気として燃焼させることで揮発性有害ガスを無害化処理できる。   According to the heat purification apparatus for contaminated soil according to claim 1 of the present invention, the heat treatment kiln that heats and purifies the contaminated soil by bringing the hot air sent from the burner into contact with the contaminated soil in a drum that is rotatably supported in an inclined manner. And an oxidative decomposition furnace for thermally decomposing pollutants in the exhaust gas on the discharge side of the heat treatment kiln, and a preliminary indirect heating system for heating the soil before purification by the retained heat of the exhaust gas discharged from the oxidative decomposition furnace A heating device and supply means for supplying contaminated soil discharged from the preheating device to the heat treatment kiln, and supplying high-temperature exhaust gas supplied from the heat treatment kiln connected to the indirect heating preheating device. A heat exchanger, a cooling tower that lowers the exhaust gas temperature, and a bag filter dust collector are provided downstream of the exhaust duct to be exhausted, while heating the contaminated soil connected to a preheating device. Therefore, a bag filter dust collector is provided downstream of the exhaust duct for exhausting low temperature gas including water vapor and volatile harmful gas generated, and the exhaust duct of the bag filter dust collector is led into the heat exchanger, and the high temperature exhaust gas Because it is configured to supply gas containing volatile harmful gas that has been heated up by heat exchange as combustion air for the burner provided in the heat treatment kiln, it uses the heat stored in the exhaust gas of the heat treatment kiln to contaminate before purification. By reducing the moisture content of the soil, it is possible to save energy such as reducing fuel costs required for soil purification and suppressing the amount of carbon dioxide generated. Moreover, since the water content ratio of the contaminated soil can be reduced by the preheating device, it is possible to eliminate the need for a pretreatment such as the conventional adjustment of the water content ratio of the contaminated soil prior to the heat treatment kiln. Furthermore, the fuel cost of the burner can be reduced by increasing the temperature of the combustion air supplied to the burner. Further, the volatile harmful gas can be rendered harmless by burning the gas containing water vapor or volatile harmful gas discharged from the preheating device as combustion air.
本発明に係る請求項2記載の汚染土壌の加熱浄化装置によれば、前記予備加熱装置は、回転自在に傾斜支持した内筒と、該内筒を覆う外筒とから成る二重筒構造とし、内筒内に汚染土壌を供給すると共に、外筒内に加熱処理キルンの排ガスを通過させる構成とした間接加熱方式の予備加熱キルンとしたので、装置構造簡単にして連続送りで効率よく予備加熱を行うことができる。   According to the contaminated soil heating and purifying apparatus according to claim 2 of the present invention, the preheating apparatus has a double cylinder structure including an inner cylinder that is rotatably supported to be inclined and an outer cylinder that covers the inner cylinder. In addition to supplying contaminated soil in the inner cylinder and passing the exhaust gas from the heat treatment kiln through the outer cylinder, the indirect heating type preheating kiln is used. It can be performed.
本発明に係る請求項3記載の汚染土壌の加熱浄化装置によれば、前記予備加熱キルンの内筒の排出端には格子状円筒体を連結し、該格子状円筒体の目開きを通過した汚染土壌は加熱処理キルンに供給し、目開きを通過しなかった塊状物は回収する構成としたので、加熱浄化前に目開きを通過しなかった礫や異物を回収除去でき、従来、加熱浄化前に行っている礫や異物を取り除くための前処理を不要とすることもできる。   According to the contaminated soil heating and purifying apparatus according to claim 3 of the present invention, a grid-like cylindrical body is connected to the discharge end of the inner cylinder of the preheating kiln, and passes through the openings of the grid-like cylindrical body. Contaminated soil is supplied to the heat-treated kiln, and the lump that has not passed through the openings is collected, so that gravel and foreign matters that have not passed through the openings can be collected and removed before heat purification. It is also possible to eliminate the need for pre-treatment for removing gravel and foreign matters that have been performed in advance.
本発明に係る請求項4記載の汚染土壌の加熱浄化装置によれば、前記予備加熱キルンの内筒内に生石灰を投入する投入手段を設けたので、汚染土壌と共に生石灰を供給すれば、高含水比の軟弱土壌でもその含水比の低減促進と共に土粒子の増粒化によって次工程の加熱処理キルンへの汚染土壌の安定的な定量供給が可能となり、浄化レベルを安定させることができる。また、従来、加熱浄化前に行っている生石灰による含水比調整等の前処理を不要とすることもできる。更には、内筒内を通過した生石灰は次工程の加熱処理キルンへと供給された後、排ガスに随伴して冷却塔を通過して水酸化カルシウムとなってバグフィルター集塵機のろ布表面に付着し、浄化の燃焼過程にて発生する酸性ガス(SOx、HCL等)と反応することで排ガスの浄化を行う効果も期待できる。   According to the heating and purifying apparatus for contaminated soil according to claim 4 of the present invention, since the charging means for supplying quick lime is provided in the inner cylinder of the preheating kiln, if the quick lime is supplied together with the contaminated soil, a high water content Even in soft soils with a specific ratio, the reduction of the water content and the increase in the number of soil particles enable stable quantitative supply of contaminated soil to the heat treatment kiln in the next step, thereby stabilizing the purification level. In addition, it is possible to eliminate the need for pretreatment such as adjustment of the water content ratio by quick lime, which has been performed before heat purification. Furthermore, after the quick lime that has passed through the inner cylinder is supplied to the heat treatment kiln of the next process, it passes through the cooling tower accompanying the exhaust gas and becomes calcium hydroxide, which adheres to the filter cloth surface of the bag filter dust collector. In addition, an effect of purifying exhaust gas can be expected by reacting with acidic gas (SOx, HCL, etc.) generated in the purification combustion process.
本発明に係る汚染土壌の浄化装置の一実施例を示す概略説明図である。It is a schematic explanatory drawing which shows one Example of the purification apparatus of the contaminated soil which concerns on this invention.
本発明に係る汚染土壌の加熱浄化装置によれば、汚染土壌を加熱浄化処理する加熱処理キルンと、該加熱処理キルンから排出される排ガスの保有熱によって浄化前の汚染土壌を加熱する予備加熱装置と、該予備加熱装置から排出される汚染土壌を前記加熱処理キルンへと供給する供給手段を備える。また、加熱処理キルンの排ガスの下流には、熱交換器、冷却塔、バグフィルター集塵機等を備える。   According to the heat purification apparatus for contaminated soil according to the present invention, a heat treatment kiln for heat purification treatment of the contaminated soil, and a preheating apparatus for heating the contaminated soil before purification by the retained heat of the exhaust gas discharged from the heat treatment kiln. And supply means for supplying contaminated soil discharged from the preheating device to the heat treatment kiln. In addition, a heat exchanger, a cooling tower, a bag filter dust collector and the like are provided downstream of the exhaust gas of the heat treatment kiln.
前記加熱処理キルンは、ダイオキシンを含む汚染土壌も処理する場合には、内周壁に耐火材を施工し、例えば約1800℃程度の高温にも耐えうるものが採用される。また、加熱処理キルンの下流には、加熱処理キルンから導出される排ガスを例えば約2秒程度滞留させ、かつ排ガス温度を約800℃程度に維持させることによって、ガス化した汚染物質を加熱分解させる酸化分解炉(二次燃焼炉)を配設する。   When the heat-treated kiln also treats contaminated soil containing dioxin, a fireproof material is applied to the inner peripheral wall, and for example, a heat-resistant kiln that can withstand a high temperature of about 1800 ° C. is used. Further, downstream of the heat treatment kiln, the exhaust gas derived from the heat treatment kiln is retained for about 2 seconds, for example, and the exhaust gas temperature is maintained at about 800 ° C., whereby the gasified pollutant is thermally decomposed. An oxidative decomposition furnace (secondary combustion furnace) is provided.
また、前記予備加熱装置は、例えば、回転自在に傾斜支持した内筒と、該内筒を覆う外筒とから成る二重筒構造とした間接加熱方式の予備加熱キルンを採用する。そして、内筒内に汚染土壌を投入する一方、内筒と外筒との間に形成されたガス通路に加熱処理キルンから導出されて酸化分解炉を通過した高温の排ガスを通過させ、汚染土壌が内筒内を転動流下する間に間接加熱して汚染土壌の含水比を低減させる。また、生石灰を予備加熱キルンの内筒内に定量投入するスクリューフィーダ等の投入手段を配設する。   In addition, the preheating device employs, for example, an indirect heating type preheating kiln having a double cylinder structure including an inner cylinder that is rotatably supported to be inclined and an outer cylinder that covers the inner cylinder. And while putting the contaminated soil into the inner cylinder, the high temperature exhaust gas led out from the heat treatment kiln and passed through the oxidative decomposition furnace is passed through the gas passage formed between the inner cylinder and the outer cylinder, and the contaminated soil Indirect heating while rolling down the inner cylinder reduces the moisture content of the contaminated soil. In addition, a feeding means such as a screw feeder for placing quick lime into the inner cylinder of the preheating kiln is provided.
また、前記予備加熱キルンの内筒の排出端には格子状円筒体を連結し、該格子状円筒体の目開きを通過した汚染土壌は適宜の供給手段、例えば供給シュートにて下位の加熱処理キルンに供給可能とし、また目開きを通過しなかった塊状物を外部へと取り出す回収シュートを配設する。   Further, a grid-like cylindrical body is connected to the discharge end of the inner cylinder of the preheating kiln, and the contaminated soil that has passed through the openings of the grid-like cylindrical body is subjected to lower heating treatment by an appropriate supply means, for example, a supply chute. A recovery chute is provided that allows supply to the kiln and takes out the lump that has not passed through the openings.
また、加熱処理キルンから排出する高温排ガスを導く排気ダクトの予備加熱キルン下流には熱交換器を配設すると共に、予備加熱キルンの内筒から排出される水蒸気や揮発性有害ガスを含む低温のガスをバグフィルター集塵機を経由させて前記熱交換器内へと導き、前記高温の排ガスと熱交換させ、昇温した予備加熱キルンのガスを加熱処理キルンに備えたバーナの燃焼用空気として供給するようにしている。   In addition, a heat exchanger is disposed downstream of the preheating kiln of the exhaust duct that guides the high-temperature exhaust gas discharged from the heat treatment kiln, and a low-temperature gas containing water vapor and volatile harmful gas discharged from the inner cylinder of the preheating kiln. Gas is passed through the bag filter dust collector into the heat exchanger, heat exchanged with the high-temperature exhaust gas, and the heated preheating kiln gas is supplied as combustion air for the burner provided in the heat treatment kiln. I am doing so.
そして、汚染土壌を浄化処理するときには、ストックヤードに貯留された汚染土壌を、例えばショベルローダにてすくい上げて予備加熱キルンの内筒内に投入する一方、内筒と外筒との間のガス通路に加熱処理キルンの高温、約800℃の排ガスを通過させ、汚染土壌が内筒内を転動流下する間に間接加熱し、汚染土壌の含水比を低減させ、次工程の加熱処理キルンへ供給できるように前処理を行う。このとき、粘土質やシルト質等の高含水比の軟弱の汚染土壌であれば、予備加熱キルンの内筒内に汚染土壌と同時に生石灰を適宜投入する。この投入された生石灰によって汚染土壌中の水分が吸収され、含水比をより低減させると共に、土粒子の増粒も促進し、次工程の加熱処理キルンへの安定的な供給が可能となる。   And when purifying the contaminated soil, the contaminated soil stored in the stock yard is scooped up by, for example, an excavator loader and put into the inner cylinder of the preheating kiln, while the gas passage between the inner cylinder and the outer cylinder The heat treatment kiln's high temperature, about 800 ° C exhaust gas is passed through and indirectly heated while the contaminated soil rolls down the inner cylinder, reducing the moisture content of the contaminated soil and supplying it to the next heat treatment kiln. Pre-process as much as possible. At this time, if it is a soft contaminated soil having a high water content such as clay and silt, quick lime is appropriately put into the inner cylinder of the preheating kiln simultaneously with the contaminated soil. Moisture in the contaminated soil is absorbed by the input quick lime, and the water content ratio is further reduced, and the increase of soil particles is also promoted, so that stable supply to the heat treatment kiln in the next step becomes possible.
汚染土壌が予備加熱キルンの内筒排出端の格子状円筒体に到達すれば、回転する格子状円筒体によって篩われ、格子状円筒体の目開きを通過した汚染土壌は供給シュートを介して加熱処理キルン内に供給され、目開きを通過しなかった礫や異物は回収シュートによって外部へと取り出される。   If the contaminated soil reaches the grid cylinder at the discharge end of the inner cylinder of the preheating kiln, it is sieved by the rotating grid cylinder, and the contaminated soil passing through the openings of the grid cylinder is heated through the supply chute. Gravel and foreign matters that have been supplied into the treatment kiln and have not passed through the mesh are taken out by the recovery chute.
汚染土壌が加熱処理キルンへと供給されると、汚染土壌はドラム内を転動流下する間に約1800℃程度の高温雰囲気にさらされ、土壌温度が約300〜400℃程度に達すると土壌中のダイオキシンが揮発並びに熱分解してガス化する。更に、土壌をそのまま加熱し続けて約600℃前後まで昇温させて浄化する。   When the contaminated soil is supplied to the heat treatment kiln, the contaminated soil is exposed to a high temperature atmosphere of about 1800 ° C. while rolling down in the drum, and when the soil temperature reaches about 300 to 400 ° C. Dioxins volatilize and thermally decompose to gasify. Furthermore, the soil is heated as it is, and is heated to about 600 ° C. to be purified.
また、加熱処理キルンから導出される排ガスは酸化分解炉へと導かれ、酸化分解炉内で約800℃の高温雰囲気に約2秒程度さらされることで、排ガス中に存在するガス化したダイオキシンを加熱分解させる。加熱処理キルン、酸化分解炉を経た高温の排ガスは前記した予備加熱キルンを経て熱交換器へと導かれる。また予備加熱キルンの内筒から排出される水蒸気や揮発性有害ガスを含む低温のガスをバグフィルター集塵機を経由させて前記熱交換器内へと導き、前記高温の排ガスと熱交換させ、約500℃に昇温した予備加熱キルンのガスを加熱処理キルンに備えたバーナへと導き、バーナの燃焼用空気として使用する。   In addition, the exhaust gas derived from the heat treatment kiln is guided to an oxidative decomposition furnace, and is exposed to a high-temperature atmosphere at about 800 ° C. for about 2 seconds in the oxidative decomposition furnace, so that the gasified dioxins present in the exhaust gas are removed. Heat decomposition. High-temperature exhaust gas that has passed through the heat treatment kiln and the oxidative decomposition furnace is guided to the heat exchanger through the preheating kiln. In addition, a low-temperature gas containing water vapor and volatile harmful gas discharged from the inner cylinder of the preheating kiln is introduced into the heat exchanger via a bag filter dust collector, and heat exchange with the high-temperature exhaust gas is performed. The gas of the preheating kiln heated up to 0 degreeC is led to the burner with which the heat processing kiln was equipped, and is used as combustion air of a burner.
このように、加熱処理キルンの排ガス保有熱を利用して浄化前の汚染土壌の含水比を低減するので、浄化処理に要する燃料費の削減や二酸化炭素の発生量の抑制といった省エネルギー化を図ることができる。また、加熱処理キルンによる浄化処理前に予備加熱キルンにて汚染土壌の含水比を低減させるので、従来のような加熱処理キルンへの投入前の汚染土壌の含水比調整などの前処理を不要とすることもできる。   In this way, the water content ratio of the contaminated soil before purification is reduced by using the heat stored in the exhaust gas of the heat treatment kiln, so that energy savings such as reduction in fuel costs required for purification treatment and suppression of carbon dioxide generation are to be achieved. Can do. In addition, since the water content of the contaminated soil is reduced by the preheating kiln before the purification treatment by the heat treatment kiln, pretreatment such as adjustment of the water content of the contaminated soil before the introduction to the heat treatment kiln is unnecessary. You can also
また、予備加熱キルンに汚染土壌と同時に生石灰を投入すれば、高含水比の軟弱土壌の含水比を低減させると共に、土粒子の増粒も促進し、次工程の加熱処理キルンへの安定的な供給が可能となり、浄化レベルを安定させることができる。また、予備加熱キルンの内筒排出端の格子状円筒体を配設することで、粒径の大きな礫や異物は次工程の加熱処理キルンに供給されずに回収除去することができ、礫や異物などを除去する前処理も不要となる。   In addition, if quick lime is added to the preheated kiln at the same time as the contaminated soil, the moisture content of the soft soil with high water content is reduced, and the increase of soil particles is promoted. Supply becomes possible and the purification level can be stabilized. In addition, by arranging a grid-like cylindrical body at the discharge end of the inner cylinder of the preheating kiln, gravel and foreign matters having a large particle size can be recovered and removed without being supplied to the heat treatment kiln in the next step. Pre-processing for removing foreign substances is also unnecessary.
更に、予備加熱キルンの内筒から排出される水蒸気や揮発性有害ガスを含む低温のガスを熱交換器にて加熱昇温し、この昇温したガスを加熱処理キルンのバーナの燃焼用空気として利用すればバーナの燃料費を削減できて省エネルギー化が図れ、かつ予備加熱キルンから排出される揮発性有害ガスも燃焼させて無害化処理できる。   Furthermore, a low temperature gas containing water vapor and volatile harmful gas discharged from the inner cylinder of the preheating kiln is heated and heated with a heat exchanger, and the heated gas is used as combustion air for the burner of the heat treatment kiln. If used, the fuel cost of the burner can be reduced, energy saving can be achieved, and volatile harmful gas discharged from the preheating kiln can be burned and detoxified.
以下、本発明の実施例を図面に基づいて説明する。   Embodiments of the present invention will be described below with reference to the drawings.
図中の1は、汚染土壌を加熱浄化する加熱処理キルンであって、例えば約1800℃程度の高温雰囲気にも耐えうるように内周壁に耐火材を施工したドラム2を機台3上に回転自在に傾斜支持し、駆動モーター(図示せず)によって所定の速度で回転させるようにしている。そして、ドラム2の一端部の投入ホッパ4側に配設したバーナ5よりドラム2内に火炎を形成して熱風を送り込む一方、投入ホッパ4の供給シュート6から汚染土壌をドラム2内に供給し、ドラム2内を転動流下させる間に汚染土壌を高温雰囲気にさらし、汚染土壌中の汚染物質を揮発または熱分解させて浄化している。   1 in the figure is a heat treatment kiln that heats and purifies contaminated soil. For example, a drum 2 with a refractory material applied to the inner peripheral wall so as to withstand a high temperature atmosphere of about 1800 ° C. is rotated on the machine base 3. It is tilted and supported freely, and is rotated at a predetermined speed by a drive motor (not shown). A flame is formed in the drum 2 from the burner 5 arranged on the charging hopper 4 side at one end of the drum 2 and hot air is sent into the drum 2, while contaminated soil is supplied into the drum 2 from the supply chute 6 of the charging hopper 4. The contaminated soil is exposed to a high temperature atmosphere while rolling down in the drum 2 to purify the pollutants in the contaminated soil by volatilization or thermal decomposition.
前記加熱処理キルン1の排出側下位には、加熱された土壌を一時貯蔵するストックビン7を配設しており、該ストックビン7内に加熱土壌を一時貯蔵することで曝気を行って土壌中に残留する微量の汚染物質をガス化させて離脱除去するようにしている。そして浄化した土壌は移送手段8にて後述する土壌冷却装置9に供給される。   In the lower part of the discharge side of the heat treatment kiln 1, a stock bin 7 for temporarily storing heated soil is disposed, and the heated soil is temporarily stored in the stock bin 7 so that aeration is performed in the soil. A small amount of contaminants remaining in the gas are gasified and removed. The purified soil is supplied to a soil cooling device 9 described later by the transfer means 8.
前記ストックビン7の上位には、加熱処理キルン1の高温、例えば800℃程度の排ガスを導入し、約2秒程度滞留させ、排ガス中の汚染物質を高温雰囲気にさらして加熱分解させる酸化分解炉10を配設している。酸化分解炉10の炉内温度を所定温度、例えば800℃に維持するために、炉内温度を検出し、該検出値に基づいてバーナ5の燃焼量を制御するようにしている。なお、バーナ5の燃焼量制御にて炉内温度を適正に維持できないときには、酸化分解炉10に補助バーナ(図示せず)を配設し、該補助バーナを制御することによって炉内温度を適正に維持するようにしても良い。   An oxidative decomposition furnace in which exhaust gas at a high temperature of the heat treatment kiln 1, for example, about 800 ° C. is introduced and retained for about 2 seconds, and the pollutants in the exhaust gas are exposed to a high temperature atmosphere and thermally decomposed above the stock bin 7. 10 is disposed. In order to maintain the furnace temperature of the oxidative decomposition furnace 10 at a predetermined temperature, for example, 800 ° C., the furnace temperature is detected, and the combustion amount of the burner 5 is controlled based on the detected value. When the furnace temperature cannot be properly maintained by controlling the combustion amount of the burner 5, an auxiliary burner (not shown) is disposed in the oxidative decomposition furnace 10, and the auxiliary furnace is controlled so as to make the furnace temperature appropriate. You may make it maintain to.
前記酸化分解炉10の排ガス下流にはダスト捕捉用のサイクロン集塵機11を配設し、該サイクロン集塵機11の排ガス下流には汚染土壌を予備加熱する予備加熱キルン12を配設する。予備加熱キルン12は、回転自在に傾斜支持した内筒13と、該内筒13を覆う外筒14とから成る二重筒構造とし、内筒13と外筒14との間に排ガスを通過させるガス通路15を形成する。また、内筒13の一端側には汚染土壌を投入するための投入ホッパ16を配設すると共に、生石灰をスクリューフィーダー(図示せず)等にて定量投入できるようにしておく。そして、汚染土壌を予備加熱キルン12の投入ホッパ16から投入して内筒13内を転動流下させる間に、ガス通路15を通過する高温排ガスによって間接加熱するようにしている。   A cyclone dust collector 11 for capturing dust is disposed downstream of the exhaust gas from the oxidative decomposition furnace 10, and a preheating kiln 12 for preheating the contaminated soil is disposed downstream of the exhaust gas of the cyclone dust collector 11. The preheating kiln 12 has a double cylinder structure including an inner cylinder 13 that is rotatably supported to be inclined and an outer cylinder 14 that covers the inner cylinder 13, and allows exhaust gas to pass between the inner cylinder 13 and the outer cylinder 14. A gas passage 15 is formed. In addition, a charging hopper 16 for charging contaminated soil is disposed on one end side of the inner cylinder 13, and quick lime can be quantitatively charged by a screw feeder (not shown) or the like. The contaminated soil is indirectly heated by the high-temperature exhaust gas passing through the gas passage 15 while the contaminated soil is introduced from the introduction hopper 16 of the preheating kiln 12 and tumbles down the inner cylinder 13.
また、内筒13の排出端には格子状円筒体17を連結し、該格子状円筒体17の目開きを通過した汚染土壌は排出ホッパ18の排出口18aから排出され、加熱処理キルン1の供給シュート6に案内されてドラム2内に供給されるようにしている一方、目開きを通過しなかった礫や異物は回収シュート19から外部へと取り出されるようにしている。   Further, a grid-like cylindrical body 17 is connected to the discharge end of the inner cylinder 13, and the contaminated soil that has passed through the openings of the grid-like cylinder 17 is discharged from the discharge port 18 a of the discharge hopper 18. While being guided by the supply chute 6 to be supplied into the drum 2, gravel and foreign matters that have not passed through the mesh are taken out from the recovery chute 19 to the outside.
なお、予備加熱キルン12への汚染土壌の投入は、ストックヤード20に貯留された浄化前の汚染土壌Aを図示しないショベルローダにてすくい上げて投入ホッパ16に直接投入するようにしても良いし、また搬送コンベヤを使用して投入するようにしても良い。このとき、含水比が高い汚染土壌を投入するのであれば、汚染土壌を内筒13内に強制的に送り込む手段を適宜取り付けることが好ましい。なお、従来のように、汚染土壌の含水比調整等の前処理を行った後、ホッパフィーダにて切り出しながら予備加熱キルン12へ投入しても良い。   In addition, the contaminated soil may be input into the preheating kiln 12 by scooping up the uncontaminated contaminated soil A stored in the stock yard 20 with an unillustrated shovel loader and directly inputting it into the input hopper 16. Moreover, you may make it throw in using a conveyance conveyor. At this time, if contaminated soil having a high water content ratio is introduced, it is preferable to appropriately attach means for forcibly feeding the contaminated soil into the inner cylinder 13. In addition, after performing pretreatments such as adjusting the water content ratio of contaminated soil as in the past, it may be put into the preheating kiln 12 while being cut out by a hopper feeder.
予熱加熱キルン12のガス通路15を通過した高温の排ガスは、排気ダクト21を通過して熱交換器22へと導入され、該熱交換器22では、後述するように、前記高温の排ガスと予備加熱キルン12の内筒13から排出される低温のガスとを熱交換させるようにしている。熱交換器22の下流には排ガスを冷却するための水冷式の冷却塔23を配設し、排ガスに対し水を噴霧してガス温度を約180℃程度まで急冷させるようにしており、これによってダイオキシンの再析出を抑えるようにしている。   The high-temperature exhaust gas that has passed through the gas passage 15 of the preheating heating kiln 12 passes through the exhaust duct 21 and is introduced into the heat exchanger 22. Heat exchange is performed with the low-temperature gas discharged from the inner cylinder 13 of the heating kiln 12. A water-cooled cooling tower 23 for cooling the exhaust gas is disposed downstream of the heat exchanger 22, and water is sprayed on the exhaust gas to rapidly cool the gas temperature to about 180 ° C. Dioxin reprecipitation is suppressed.
冷却塔23の下流には、バグフィルター集塵機24を配設する一方、重質油やVOCの加熱浄化過程にて生成される有害物質である硫黄酸化物や塩化水素を中和するための消石灰を貯蔵する消石灰貯蔵ビン25を配設し、所定量の消石灰を切り出すスクリューフィーダー26や排気ダクト21内に消石灰を吹き込むブロア(図示せず)等より成る消石灰供給装置を備え、該消石灰供給装置によって消石灰をバグフィルター集塵機24の入口側の排気ダクト21内に適宜量吹き込み、バグフィルター集塵機24内で硫黄酸化物や塩化水素を中和させるようにしている。なお、消石灰に活性炭を混入し、バグフィルター集塵機24に吹き込んでろ布に被覆させ、排ガス中のダイオキシンを活性炭に吸着させて除去しても良いし、また、活性炭を消石灰に混入して吹き込むのではなく、バグフィルター24の下流に活性炭捕捉用のバグフィルター集塵機(図示せず)を配設し、該バグフィルター集塵機の上流に活性炭を単独にて吹き込むようにしても良い。   A bag filter dust collector 24 is disposed downstream of the cooling tower 23, while slaked lime for neutralizing sulfur oxides and hydrogen chloride, which are harmful substances generated in the heating and purification process of heavy oil and VOC, is provided. A slaked lime storage bottle 25 for storing the slaked lime is provided, and includes a screw feeder 26 for cutting out a predetermined amount of slaked lime, a blower (not shown) for blowing slaked lime into the exhaust duct 21, and the like. Is appropriately blown into the exhaust duct 21 on the inlet side of the bag filter dust collector 24 so that sulfur oxide and hydrogen chloride are neutralized in the bag filter dust collector 24. In addition, activated carbon may be mixed into slaked lime, blown into the bag filter dust collector 24 and covered with a filter cloth, and dioxins in the exhaust gas may be adsorbed and removed by activated carbon. Alternatively, a bag filter dust collector (not shown) for capturing activated carbon may be provided downstream of the bag filter 24, and activated carbon may be blown alone upstream of the bag filter dust collector.
バグフィルター集塵機24の下流には、排ガスを吸引排気する排風機27が配設され、バーナ5から加熱処理キルン1内に供給する燃焼ガスを過不足なしに吸引するために、投入ホッパ4の隅部にて検出する静圧がほぼ大気圧程度となるように排気ダクト21内の風量調整ダンパー(図示せず)の開度または排風機27の回転数を制御して吸引量調整を行っている。そして、排風機27を通過した排ガスは煙突28から大気中に放出される。   Downstream of the bag filter dust collector 24, an exhaust fan 27 for sucking and exhausting exhaust gas is disposed. In order to suck the combustion gas supplied from the burner 5 into the heat treatment kiln 1 without excess or deficiency, a corner of the charging hopper 4 is provided. The suction amount is adjusted by controlling the opening degree of the air volume adjusting damper (not shown) in the exhaust duct 21 or the rotational speed of the exhaust fan 27 so that the static pressure detected by the air outlet becomes approximately atmospheric pressure. . The exhaust gas that has passed through the exhaust fan 27 is released from the chimney 28 into the atmosphere.
また、予備加熱キルン12の排出ホッパ18には、内筒13から排出される水蒸気や揮発性有害ガスを含む低温のガスを排気する排気ダクト29が連結され、該排気ダクト29の下流にはバグフィルター集塵機30、排風機31、32が配設されると共に、排気ダクト29の末端は熱交換器22を通過して加熱処理キルン1のバーナ5に連結されている。そして、内筒13から排気される揮発性有害ガスを含む低温のガスをバグフィルター集塵機30にて清浄化し、熱交換器22を通過させることで、予備加熱キルン12のガス通路15から排出される高温の排ガスと熱交換させ、約500℃に昇温させたガスをバーナ5の燃焼用空気として使用している。このように、予備加熱キルン12の内筒13から排出される水蒸気や揮発性有害ガスを含むガスを加熱処理キルン1のバーナ5にて燃焼させることで、揮発性有害ガスを無害化処理すると共に、昇温させた燃焼用空気を使用することでバーナの燃料費を削減している。   The discharge hopper 18 of the preheating kiln 12 is connected to an exhaust duct 29 for exhausting low-temperature gas including water vapor and volatile harmful gas discharged from the inner cylinder 13, and a bug is disposed downstream of the exhaust duct 29. A filter dust collector 30 and exhaust fans 31 and 32 are disposed, and the end of the exhaust duct 29 passes through the heat exchanger 22 and is connected to the burner 5 of the heat treatment kiln 1. And the low-temperature gas containing the volatile harmful gas exhausted from the inner cylinder 13 is cleaned by the bag filter dust collector 30 and passed through the heat exchanger 22, so that it is discharged from the gas passage 15 of the preheating kiln 12. A gas that is heat-exchanged with high-temperature exhaust gas and heated to about 500 ° C. is used as combustion air for the burner 5. In this way, the gas containing water vapor and volatile harmful gas discharged from the inner cylinder 13 of the preheating kiln 12 is burned in the burner 5 of the heat treatment kiln 1 to detoxify the volatile harmful gas. By using combustion air that has been heated, burner fuel costs are reduced.
また、土壌冷却装置9は、公知の装置であり、ストックビン7に貯蔵した高温の土壌を冷却して取り扱いやすいようにするもので、例えば、ロータリーキルン方式のものを採用し、内部に掻き上げ羽根を周設した円筒状のドラム33を機台34上に回転自在に傾斜支持し、駆動装置(図示せず)により所定の速度で回転させている。   The soil cooling device 9 is a well-known device that cools the high-temperature soil stored in the stock bin 7 so that it can be easily handled. For example, a rotary kiln type is used, and a scraping blade is used inside. A cylindrical drum 33 is provided on the machine base 34 so as to be rotatable and is rotated at a predetermined speed by a driving device (not shown).
前記ドラム33の一端には投入ホッパ35を、他端には排出ホッパ36を配設し、加熱土壌を投入ホッパ35側から投入し、掻き上げ羽根によって掻き上げながら排出ホッパ36側へと移動させる間に、水貯留タンク37に貯留する水を水噴射ノズル38から噴射することによって加熱土壌を冷却すると共に、埃が出にくい程度に含水率を高めて取り扱いやすい状態にしている。また、土壌冷却装置9にて発生する埃や水蒸気は、排気ダクト39の末端に配設した排風機40によって吸引排気し、バグフィルター集塵機41にてダストを捕捉してから煙突28より大気中に放出するようにしている。   A charging hopper 35 is disposed at one end of the drum 33, and a discharging hopper 36 is disposed at the other end. In the meantime, the water stored in the water storage tank 37 is sprayed from the water spray nozzle 38 to cool the heated soil, and the moisture content is increased to such an extent that dust is not easily produced, thereby making it easy to handle. Further, dust and water vapor generated in the soil cooling device 9 are sucked and exhausted by the exhaust fan 40 disposed at the end of the exhaust duct 39, captured by the bag filter dust collector 41, and then introduced into the atmosphere from the chimney 28. It is trying to release.
次に、上記浄化装置によってダイオキシンを含む汚染土壌を浄化処理する場合について説明する。汚染土壌を浄化処理するときには、先ず、排風機27、31、32を稼働しながら加熱処理キルン1のバーナ5を燃焼させ、内周壁に施工した耐火材を加熱してドラム2内を高温雰囲気に維持する。これによって加熱処理キルン1の排ガス下流の予備加熱キルン12や熱交換器22も加熱されて浄化の準備が整う。   Next, the case where the contaminated soil containing dioxin is purified by the purification device will be described. When purifying the contaminated soil, first, the burner 5 of the heat treatment kiln 1 is burned while operating the exhaust fans 27, 31, 32, and the refractory material applied to the inner peripheral wall is heated to bring the drum 2 into a high temperature atmosphere. maintain. As a result, the preheating kiln 12 and the heat exchanger 22 downstream of the exhaust gas of the heat treatment kiln 1 are also heated, and preparation for purification is completed.
続いて、ストックヤード20に貯留した汚染土壌Aを例えばショベルローダにてすくい上げて予備加熱キルン12の投入ホッパ16内に投入すると、汚染土壌は内筒13内を転動流下する間にガス通路15を通過する高温排ガスによって間接的に加熱され、汚染土壌の含水比が徐々に低下していき、内筒13の排出端に達すると格子状円筒体17によって篩われ、格子状円筒体17の目開きを通過した汚染土壌は排出ホッパ18の排出口18aから排出され、加熱処理キルン1の供給シュート6に案内されてドラム2内に供給される。また、目開きを通過しなかった礫や異物は回収シュート19から外部へと取り出される。   Subsequently, when the contaminated soil A stored in the stock yard 20 is scooped up by, for example, an excavator loader and introduced into the charging hopper 16 of the preheating kiln 12, the contaminated soil is in a gas passage 15 while rolling down the inner cylinder 13. The moisture content of the contaminated soil is gradually reduced by the high-temperature exhaust gas passing through the inner cylinder 13, and when it reaches the discharge end of the inner cylinder 13, it is sieved by the grid cylinder 17. The contaminated soil that has passed through the opening is discharged from the discharge port 18 a of the discharge hopper 18, guided to the supply chute 6 of the heat treatment kiln 1, and supplied into the drum 2. Further, gravel and foreign matters that have not passed through the openings are taken out from the collection chute 19 to the outside.
なお、高含水比の汚染土壌を予備加熱キルン12に投入するときには、所定量の生石灰を同時に投入する。これによって、汚染土壌が内筒13内を流下する間に生石灰の作用によって汚染土壌の含水比が一層低減すると共に、土粒子の増粒を促進し、次工程の加熱処理キルン1の加熱浄化の前処理を効果的に行うことができる。   Note that when a contaminated soil having a high water content is charged into the preheating kiln 12, a predetermined amount of quicklime is simultaneously charged. As a result, the moisture content of the contaminated soil is further reduced by the action of quick lime while the contaminated soil flows down the inner cylinder 13, and the increase of the soil particles is promoted, so that the heat treatment kiln 1 in the next process can be heated and purified. Pretreatment can be performed effectively.
予備加熱キルン12から加熱処理キルン1に供給された汚染土壌は、約300〜400℃に加熱されると土壌中のダイオキシンが揮発並びに熱分解してガス化する。この土壌をそのまま加熱し続けて約600℃前後に昇温させてから加熱処理キルン1出口のストックビン7へと投入して貯蔵する。ストックビン7において約600℃前後の加熱土壌をしばらく、例えば約1時間程度貯蔵して曝気を行うことによって土壌中に残留する微量のダイオキシンをガス化させて離脱させる。   When the contaminated soil supplied from the preheating kiln 12 to the heat treatment kiln 1 is heated to about 300 to 400 ° C., dioxins in the soil volatilize and thermally decompose to gasify. The soil is heated as it is to raise the temperature to about 600 ° C. and then put into the stock bin 7 at the outlet of the heat treatment kiln 1 for storage. In the stock bottle 7, the heated soil at about 600 ° C. is stored for a while, for example, for about 1 hour, and aerated, whereby a small amount of dioxin remaining in the soil is gasified and separated.
加熱処理キルン1及びストックビン7にてガス化したダイオキシンは、排ガスに随伴して酸化分解炉10へと導かれ、酸化分解炉10内で約800℃の高温雰囲気に約2秒程度さらされることで、ガス化したダイオキシンが加熱分解される。このとき、酸化分解炉10内のガス温度を温度センサーにて逐次計測し、ダイオキシンを加熱分解できる温度、例えば約800℃程度となるようにバーナ5の燃焼量を制御する。なお、酸化分解炉10の炉内温度をバーナ5の燃焼量にて適正に制御しにくいときには補助バーナ(図示せず)にて炉内温度を制御する。   The dioxins gasified in the heat treatment kiln 1 and the stock bin 7 are guided to the oxidative decomposition furnace 10 along with the exhaust gas, and are exposed to a high temperature atmosphere of about 800 ° C. in the oxidative decomposition furnace 10 for about 2 seconds. Thus, the gasified dioxin is thermally decomposed. At this time, the gas temperature in the oxidative decomposition furnace 10 is sequentially measured by a temperature sensor, and the combustion amount of the burner 5 is controlled so as to reach a temperature at which dioxins can be thermally decomposed, for example, about 800 ° C. In addition, when it is difficult to appropriately control the furnace temperature of the oxidative decomposition furnace 10 by the combustion amount of the burner 5, the furnace temperature is controlled by an auxiliary burner (not shown).
酸化分解炉10から導出される高温の排ガスは、サイクロン集塵機11を経て予備加熱キルン12のガス通路15へと導かれ、内筒13内を転動流下する汚染土壌を間接加熱した後、排気ダクト21内を通って熱交換器22に導入される。   The high-temperature exhaust gas derived from the oxidative decomposition furnace 10 is guided to the gas passage 15 of the preheating kiln 12 through the cyclone dust collector 11, and indirectly heats the contaminated soil that tumbles down in the inner cylinder 13, and then the exhaust duct. 21 is introduced into the heat exchanger 22.
前記熱交換器22には、予備加熱キルン12の排出ホッパ18から排出される水蒸気や揮発性有害ガスを含む低温のガスが排気ダクト29を通過し、バグフィルター集塵機30を経由して導入され、前記予備加熱キルン12のガス通路15を通過した高温の排ガスとの間で熱交換が行われる。そして約500℃程度に昇温した揮発性有害ガスを含むガスは加熱処理キルン1のバーナ5に導入され、燃焼用空気として使用される。   In the heat exchanger 22, low temperature gas including water vapor and volatile harmful gas discharged from the discharge hopper 18 of the preheating kiln 12 passes through the exhaust duct 29 and is introduced via the bag filter dust collector 30. Heat exchange is performed with the high-temperature exhaust gas that has passed through the gas passage 15 of the preheating kiln 12. And the gas containing the volatile harmful gas heated up to about 500 degreeC is introduce | transduced into the burner 5 of the heat processing kiln 1, and is used as combustion air.
また、熱交換器22の排気ダクト21から導出される排ガスは、冷却塔23へと導かれ、水を噴射して排ガス温度をダイオキシンが再析出しない約180℃程度まで急冷させてダイオキシンの再析出を抑えた後、バグフィルター集塵機24へと導かれる。   Further, the exhaust gas led out from the exhaust duct 21 of the heat exchanger 22 is guided to the cooling tower 23, and water is injected to rapidly cool the exhaust gas temperature to about 180 ° C. where the dioxin does not reprecipitate, thereby reprecipitation of the dioxin. After being suppressed, it is guided to the bag filter dust collector 24.
前記バグフィルター集塵機24の手前では活性炭を混入した消石灰を消石灰供給装置にて吹き込んでバグフィルター集塵機24のろ布表面に被覆させておき、排ガス中のダイオキシンを活性炭で吸着する。また、土壌中に重質油を含んでいると加熱過程で硫黄成分により硫黄酸化物が生成され、またVOCを含んでいると酸化分解及び熱分解する過程でホスゲンが生成し、これに水蒸気を添加することで加水分解によって塩化水素が生成されることとなるので、これら排ガス中の酸性ガス(SOx、HCL等)を消石灰にて中和する。そして、バグフィルター集塵機24にて消石灰、活性炭、及びダスト微粒分を除去して清浄となったガスを煙突28から大気中へと放出する。   In front of the bag filter dust collector 24, slaked lime mixed with activated carbon is blown with a slaked lime supply device so as to cover the filter cloth surface of the bag filter dust collector 24, and dioxins in the exhaust gas are adsorbed by the activated carbon. In addition, if heavy oil is contained in the soil, sulfur oxides are produced by sulfur components during the heating process, and if VOC is contained, phosgene is produced in the process of oxidative decomposition and thermal decomposition, and water vapor is added to this. When added, hydrogen chloride is generated by hydrolysis, so acid gases (SOx, HCL, etc.) in these exhaust gases are neutralized with slaked lime. Then, the bag filter dust collector 24 removes slaked lime, activated carbon, and dust fine particles and releases the gas, which has been cleaned, from the chimney 28 to the atmosphere.
また、ストックビン7に貯蔵された加熱土壌は、高温であるため取り扱いやすい温度まで冷却するために土壌冷却装置9に供給される。土壌冷却装置9に供給された土壌は、ドラム33内を転動流下する間に水噴霧ノズル38から水を噴霧されて冷却され、取り扱いやすい状態になって排出ホッパ36から排出されて山積みとした後に処理される。また、ドラム33内にて発生する埃や水蒸気は排風機40によって吸引排気されて下流のバグフィルター集塵機41へと導かれ、埃が捕捉された後に煙突28より排気される。   In addition, the heated soil stored in the stock bin 7 is supplied to the soil cooling device 9 in order to cool it to a temperature that is easy to handle because it is hot. The soil supplied to the soil cooling device 9 is cooled by being sprayed with water from the water spray nozzle 38 while rolling down in the drum 33, becomes easy to handle, is discharged from the discharge hopper 36, and is piled up. It will be processed later. Further, dust and water vapor generated in the drum 33 are sucked and exhausted by the exhaust fan 40 and guided to the downstream bag filter dust collector 41, where the dust is trapped and exhausted from the chimney 28.
このように、予備加熱キルン12において加熱処理キルン1の排ガス保有熱を利用して浄化前の汚染土壌の含水比を低減するので、浄化処理に要する燃料費の削減や二酸化炭素の発生量の抑制といった省エネルギー化を図ることができる。また、予備加熱キルン12にて汚染土壌の含水比を低減できるので、従来のような加熱処理キルンへの投入前の含水比調整などの前処理も不要とすることができる。   Thus, since the water content ratio of the contaminated soil before purification is reduced by using the heat stored in the exhaust gas of the heat treatment kiln 1 in the preheating kiln 12, the fuel cost required for the purification treatment and the generation amount of carbon dioxide are suppressed. Energy saving. Moreover, since the water content ratio of the contaminated soil can be reduced by the preheating kiln 12, it is possible to eliminate the need for pretreatment such as adjustment of the water content ratio before charging into the heat treatment kiln.
なお、予備加熱装置として間接加熱方式の予備加熱キルン12を採用したが何らこれに限定するものではなく、要は加熱処理キルン1から導出される排ガスの保有熱にて浄化前の汚染土壌を予備加熱できる装置であれば良く、本発明を逸脱しない範囲内での種々の変形は可能である。   Although the indirect heating type preheating kiln 12 is used as the preheating device, the present invention is not limited to this. In short, the contaminated soil before purification is preliminarily preserved by the retained heat of the exhaust gas derived from the heat treatment kiln 1. Any device capable of heating can be used, and various modifications can be made without departing from the scope of the present invention.
1…加熱処理キルン 5…バーナ
6…供給シュート(供給手段) 7…ストックビン
9…土壌冷却装置 10…酸化分解炉
12…予備加熱キルン(予備加熱装置) 13…内筒
14…外筒 15…ガス通路
16…投入ホッパ 17…格子状円筒体
18…排出ホッパ 18a…排出口
19…回収シュート 22…熱交換器
23…冷却塔 24…バグフィルター集塵機
25…消石灰貯蔵ビン
26…スクリューフィーダー(消石灰供給装置)
DESCRIPTION OF SYMBOLS 1 ... Heat processing kiln 5 ... Burner 6 ... Supply chute (supply means) 7 ... Stock bottle 9 ... Soil cooling device 10 ... Oxidation cracking furnace 12 ... Preheating kiln (preheating device) 13 ... Inner cylinder 14 ... Outer cylinder 15 ... Gas passage 16 ... Input hopper 17 ... Grid-shaped cylinder 18 ... Discharge hopper 18a ... Discharge port 19 ... Recovery chute 22 ... Heat exchanger 23 ... Cooling tower 24 ... Bag filter dust collector 25 ... Slaked lime storage bottle 26 ... Screw feeder (slaked lime supply) apparatus)

Claims (4)

  1. 回転自在に傾斜支持したドラム内でバーナから送り込む熱風と汚染土壌とを接触させて汚染土壌を加熱浄化処理する加熱処理キルンと、該加熱処理キルンの排出側には排ガス中の汚染物質を加熱分解させる酸化分解炉と、該酸化分解炉から排出される排ガスの保有熱によって浄化前の土壌を加熱する間接加熱方式の予備加熱装置と、該予備加熱装置から排出される汚染土壌を前記加熱処理キルンへと供給する供給手段とを備え、前記間接加熱方式の予備加熱装置に連結した加熱処理キルンから供給される高温排ガスを排気する排気ダクトの下流には熱交換器と、排ガス温度を低下させる冷却塔と、バグフィルター集塵機とを備える一方、予備加熱装置に連結した汚染土壌の加熱によって発生する水蒸気や揮発性有害ガスを含む低温のガスを排気する排気ダクトの下流にはバグフィルター集塵機を備え、該バグフィルター集塵機の排気ダクトを前記熱交換器内へと導き、前記高温の排ガスと熱交換させて昇温した揮発性有害ガスを含むガスを加熱処理キルンに備えたバーナの燃焼用空気として供給する構成としたことを特徴とする汚染土壌の加熱浄化装置。   A heat treatment kiln that heats and purifies the contaminated soil by bringing hot air sent from the burner into contact with the contaminated soil in a drum that is rotatably supported in a tiltable manner, and the pollutants in the exhaust gas are thermally decomposed on the discharge side of the heat treatment kiln An oxidative decomposition furnace to be heated, a preheating device of an indirect heating method for heating the soil before purification by the retained heat of exhaust gas discharged from the oxidative decomposition furnace, and the contaminated soil discharged from the preheating device to the heat treatment kiln A heat exchanger downstream of the exhaust duct for exhausting the high-temperature exhaust gas supplied from the heat treatment kiln connected to the indirect heating type preheating device, and cooling for reducing the exhaust gas temperature While equipped with a tower and bag filter dust collector, exhausts low-temperature gases including water vapor and volatile harmful gases generated by heating contaminated soil connected to a preheating device. A bag filter dust collector is provided downstream of the exhaust duct, and the exhaust duct of the bag filter dust collector is led into the heat exchanger, and gas containing volatile harmful gas heated by exchanging heat with the high-temperature exhaust gas. A heat purification apparatus for contaminated soil, characterized in that it is configured to supply as combustion air for a burner provided in a heat treatment kiln.
  2. 前記予備加熱装置は、回転自在に傾斜支持した内筒と、該内筒を覆う外筒とから成る二重筒構造とし、内筒内に汚染土壌を供給すると共に、外筒内に加熱処理キルンの排ガスを通過させる構成とした間接加熱方式の予備加熱キルンとしたことを特徴とする請求項1記載の汚染土壌の加熱浄化装置。   The preheating device has a double cylinder structure comprising an inner cylinder that is rotatably and tiltably supported and an outer cylinder that covers the inner cylinder, supplies contaminated soil into the inner cylinder, and heat-treats the kiln in the outer cylinder. 2. The apparatus for heating and purifying contaminated soil according to claim 1, wherein a preheating kiln of an indirect heating system configured to allow the exhaust gas to pass through is used.
  3. 前記予備加熱キルンの内筒の排出端には格子状円筒体を連結し、該格子状円筒体の目開きを通過した汚染土壌は加熱処理キルンに供給し、目開きを通過しなかった塊状物は回収する構成としたことを特徴とする請求項2記載の汚染土壌の加熱浄化装置。   A grid-like cylinder is connected to the discharge end of the inner cylinder of the preheating kiln, and the contaminated soil that has passed through the openings of the grid-like cylinder is supplied to the heat treatment kiln, and the lump that has not passed through the openings The apparatus for collecting and purifying contaminated soil according to claim 2, wherein:
  4. 前記予備加熱キルンの内筒内に生石灰を投入する投入手段を設けたことを特徴とする請求項1乃至3のいずれかに記載の汚染土壌の加熱浄化装置。   The apparatus for heating and purifying contaminated soil according to any one of claims 1 to 3, further comprising a charging means for charging quicklime into an inner cylinder of the preheating kiln.
JP2013044950A 2013-03-07 2013-03-07 Heat-cleaning apparatus for contaminated soil Pending JP2013150981A (en)

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN105180171A (en) * 2015-10-19 2015-12-23 深圳市创辉煌环保科技发展有限公司 Garbage treatment method and garbage treatment equipment
CN105834204A (en) * 2016-05-12 2016-08-10 贵州省环境科学研究设计院 Soil mercury removing system

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN105180171A (en) * 2015-10-19 2015-12-23 深圳市创辉煌环保科技发展有限公司 Garbage treatment method and garbage treatment equipment
CN105180171B (en) * 2015-10-19 2017-12-08 深圳市创辉煌环保科技发展有限公司 A kind of waste disposal method and its processing equipment
CN105834204A (en) * 2016-05-12 2016-08-10 贵州省环境科学研究设计院 Soil mercury removing system

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