JP4039647B2 - Method and apparatus for treating dust in waste melting furnace - Google Patents

Method and apparatus for treating dust in waste melting furnace Download PDF

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JP4039647B2
JP4039647B2 JP17513998A JP17513998A JP4039647B2 JP 4039647 B2 JP4039647 B2 JP 4039647B2 JP 17513998 A JP17513998 A JP 17513998A JP 17513998 A JP17513998 A JP 17513998A JP 4039647 B2 JP4039647 B2 JP 4039647B2
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dust
waste
melting furnace
waste melting
furnace
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JPH11221545A (en
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猛 西
也寸彦 加藤
一毅 村橋
和浩 栗林
秀治 芝池
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Nippon Steel Engineering Co Ltd
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Nippon Steel Engineering Co Ltd
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    • YGENERAL 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
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02PCLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P80/00Climate change mitigation technologies for sector-wide applications
    • Y02P80/10Efficient use of energy, e.g. using compressed air or pressurized fluid as energy carrier
    • Y02P80/15On-site combined power, heat or cool generation or distribution, e.g. combined heat and power [CHP] supply
    • YGENERAL 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
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02WCLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
    • Y02W30/00Technologies for solid waste management
    • Y02W30/20Waste processing or separation

Description

【0001】
【発明の属する技術分野】
本発明は、一般廃棄物、産業廃棄物等を直接溶融処理する廃棄物溶融炉において発生するダストの処理方法及びその装置に関する。
【0002】
【従来の技術】
シャフト炉方式の廃棄物溶融炉で廃棄物を直接溶融する廃棄物溶融処理は、廃棄物溶融炉に装入された一般廃棄物あるいは産業廃棄物等を乾燥、熱分解、燃焼、溶融の過程を経て、廃棄物をスラグ及びメタルとして取り出し、これらを再資源化するものである。
【0003】
図7〜図9は一般廃棄物あるいは産業廃棄物等の廃棄物の直接溶融処理の系統図である。廃棄物を廃棄物溶融炉1の炉頂の装入口から装入するとともに副原料装入口からコークス及び石灰石等の副原料を廃棄物溶融炉内に装入し、これらは炉内で充填層を形成している。
【0004】
廃棄物溶融炉1は、円形断面のシャフト型の炉体をしており、炉体の下部には下段羽口5及び上段羽口6が設けられ、これらの羽口5,6から、酸素を富化した空気あるいは空気を吹き込み、前記コークスおよび廃棄物を燃焼させる。
【0005】
廃棄物溶融炉1内では、ごみの熱分解残渣及びコークスの燃焼により、廃棄物は、乾燥・予熱(約300℃)、熱分解(300〜1000℃)、燃焼・溶融(1700〜1800℃)の過程を経て、メタルとスラグの溶融物になり、水砕処理し、磁選機でメタルとスラグを分離し、これらを再資源化する。
【0006】
廃棄物溶融炉1においては、装入物中の可燃分が熱分解して残渣(チャー)が発生し、残渣は羽口6から送られてきた空気によって燃焼し、その灰分は溶融してスラグ化するが、微細なものは羽口6から送られてきた空気によって燃焼されることなく、気流によって炉から可燃性ダストとなって飛散する。
【0007】
廃棄物溶融炉1で飛散した可燃性ダストを含む熱分解ガスは、従来、図8に示すように、サイクロン等の除塵器7を介さずにそのまま燃焼室12に送って燃焼させるか、あるいは図9に示すようにサイクロン等の除塵器7を設ける場合でも捕集された可燃性ダストは、可燃性ダストを貯蔵するホッパと貯蔵された可燃性ダストを定量的に切り出しする装置と、さらに熱分解ガス中に均一に分散させる装置を介して熱分解ガスに混合させ、やはり燃焼室12に送って燃焼させていた。
【0008】
燃焼により発生した燃焼排ガス(800〜900℃)は廃熱ボイラー13に送られて熱回収され、排ガス温度調節器14及び集塵器15を経て大気に放出する。
【0009】
廃棄物溶融炉から飛散する可燃性ダストの処理技術として、本出願人は、特開平7−88462号で、飛散する可燃性ダストを捕集し、捕集したダストを羽口より吹き込み、熱源として再利用することにより、廃棄物の乾燥及び溶融の熱源となるコークス等の補助燃料を削減する技術を提案した。この技術は、図7に示すように、除塵器7により捕集された可燃性ダストを可燃性ダストホッパー8に一時的に貯蔵した後、所定量を切り出し、羽口6より炉内に吹き込むことにより、ダスト中の可燃分が廃棄物溶融炉1の熱源として利用できるので、補助燃料であるコークスを削減することができるというものである。
【0010】
しかしながら、廃棄物溶融炉で発生した塩化物は、可燃性ダストに付着するので、除塵器により捕集した可燃性ダストを羽口より炉内に吹き込むと、可燃性ダストに付着した塩化物は再び廃棄物溶融炉に吹き込まれ、炉内の高温条件下でガス化し再飛散し、廃棄物溶融炉の後流の燃焼室、ボイラー、排ガス処理設備へ移行し、ボイラーの配管等を腐食させる。
【0011】
廃棄物処理において、塩化物によりボイラーの配管等が腐食するのを防止するために、例えば、特開平4−121511号公報には、廃棄物の熱分解炉で発生する熱分解ガスに反応剤を供給し、フィルターで除塵した清浄ガスをボイラーに導入し、フィルターで除去された反応生成物や飛灰は飛灰再生装置で再生され、再び反応剤とともに、反応器へ送る廃棄物処理装置が記載されている。
【0012】
また、特開平9−89227号公報には、熱分解炉で発生した塩素分を含むガスを2次燃焼室で熱回収し、熱分解炉で発生する残渣を溶融処理し、塩素を含まない排ガスにより廃熱ボイラーで発生した蒸気を高温高圧化する廃棄物熱分解溶融システムが記載されている。
【0013】
【発明が解決しようとする課題】
しかしながら、特開平4−121511号公報記載の廃棄物処理装置では、フィルターで除去された反応生成物や飛灰は、飛灰再生装置で再生され、再び反応剤とともに、反応器へ循環させるため、塩化物が系外から抜けることがなく、システムとして不完全である。
【0014】
また、特開平9−89227号公報記載の廃棄物熱分解溶融システムは、廃棄物を燃焼させる設備が、熱分解炉、2次燃焼室、溶融炉の3ヶ所となり、システムが複雑となるばかりでなく、塩素分を含んだ排ガスが2次燃焼室後流の廃熱ボイラーに流入するため、ボイラー部分で500℃〜300℃に排ガスが冷却される過程でダイオキシン類が再合成されることになる。また、廃棄物溶融炉の高温排ガスをボイラーの低温ガスに混合した後で熱回収することになるので、伝熱効率も悪くなる。
【0015】
本発明は、廃棄物を直接溶融する廃棄物溶融炉において発生する可燃性ダストを含む熱分解ガスから塩化物を除去することにより塩化物によるボイラー配管等の腐食を防止するとともに、ボイラーの除冷過程でのダイオキシンの再合成も防止するダストの処理方法及びその装置を提供するものである。
【0016】
【課題を解決するための手段】
本発明の廃棄物溶融炉におけるダストの処理方法は、廃棄物を直接溶融するシャフト炉方式の廃棄物溶融炉から飛散する可燃性ダストを含む熱分解ガスからダストを燃焼室に入る前に捕集し、捕集したダスト中の塩類を水で抽出した後脱水し、脱水した抽出液を排ガス温度調節器内に噴霧して蒸発させるとともに、前記脱水後の脱水ケーキを廃棄物溶融炉に再投入することを特徴とする。
【0017】
また、本発明の廃棄物溶融炉におけるダストの処理設備は、シャフト炉方式の廃棄物溶融炉から発生する熱分解ガスを燃焼室に導く熱分解ガスダクトに設けた除塵器と、除塵器で捕集したダスト中の塩類を水で抽出する抽出器と、固形分と抽出液を分離する脱水器と廃熱ボイラーに過熱蒸気の発生器を設けるとともに、排ガス温度調節器に脱水した抽出液を蒸発するためのスプレーノズル又はディスクアトマイザーを設けたことを特徴とする。
【0018】
【発明の実施の形態】
本発明の可燃性ダストを含むダストの処理方法では、廃棄物溶融炉の熱分解ガスからダストを捕集する前に、熱分解ガスに脱塩剤を脱塩剤添加装置で添加してガス状の塩化物を固体化することにより、ガス状の塩化水素を固体状の塩化物に変えて除塵器で捕集することもできる。その結果、塩化物の少ない排ガス中に、廃熱ボイラーを設けることができる。
【0019】
また、可燃性ダストが捕集された熱分解ガスを処理する燃焼室、廃熱ボイラー、排ガス温度調節器、集塵器等の排ガス処理設備から回収した飛灰を、捕集したダストと混合することにより、脱水ケーキの強度が上がり、また、飛灰の最終処分量を減少させることができる。
【0020】
さらに、脱水機から発生する抽出液を排ガス温度調節器内に噴霧して蒸発させることにより、系外への排水量をなくすか、もしくは減少させることができる。
【0021】
図1は廃棄物溶融炉におけるダストの処理設備の例を示す概略図である。廃棄物を直接溶融するシャフト炉方式の廃棄物溶融炉1は、前述の従来の廃棄物溶融炉と変わるところはなく、炉上部に、廃棄物、コークス、石灰石を装入するための2重シール弁機構の装入装置2、熱分解ガスを排気するための熱分解ガスダクト3が設けられ、炉下部には、スラグを排出するための出滓口4、空気と酸素を混合した酸素富化空気を吹き込む下段羽口5、空気を吹き込む上段羽口6が設けられている。
【0022】
ダストホッパー8に貯蔵されたダストを、水の入った洗浄漕9に投入し、反応を促進するために撹拌器10で撹拌して、水洗浄する。水洗浄により塩化物、硫酸塩などの水溶性成分は水に溶出する。その後、洗浄液は脱水機11で脱水され、塩類の少ない脱水ケーキと、塩類が溶出した排水とに分離される。塩類を含んだ排水は、無害化処理して放出する。
【0023】
塩類が除去された脱水ケーキは、廃棄物溶融炉1の炉頂から再投入され、脱水ケーキ中の可燃分は廃棄物溶融炉内で熱分解ガス化され、スラグ成分は溶融スラグ化される。
【0024】
除塵器7により塩類の付着した可燃性ダストを取り除いた可燃性ガスは、燃焼室12へ送って燃焼させ、燃焼により発生した排ガスは廃熱ボイラー13に送られて熱回収され、排ガス温度調節器14で冷却し、バグフィルター15で集塵した後、大気へ放出する。燃焼室12、廃熱ボイラー13及び排ガス温度調節器14から出る飛灰は混練造粒して廃棄物溶融炉に装入し、バグフィルター15の集塵灰は無害化処理する。
【0025】
発明者等は、このにおける、可燃性ダストを含む熱分解ガス中の塩素分の挙動に注目し、廃棄物溶融炉1から発生する熱分解ガスの温度を変化させ、熱分解ガス中の塩素濃度、ダスト濃度、及びダスト中の塩素含有率を測定することにより、熱分解ガス中に含まれるガス状及び固体状の塩素分の量について調査した。
【0026】
図2は、熱分解ガス単位体積当たりのガス状及び固体状の塩素重量を示しており、更に、この結果より熱分解ガス温度を変化させた場合の〔固体状の塩素分〕/〔ガス状及び固体状の塩素分〕を図3に示す。
【0027】
この図から明かなように、熱分解ガスの温度が400℃前後以下では、熱分解ガス中の塩素分は、ガス状よりも固体状、即ちダスト中に多く含まれている。
【0028】
これは、廃棄物溶融炉から発生する熱分解ガス中には、塩化アンモニウム(昇華点338℃)等の低沸点(昇華点)の塩類として存在する塩素分が含まれ、これらは低温条件で析出し、固体状の塩類としてダストに付着するためだと思われる。また、熱分解ガス中にHClが存在する場合も、ガス温度を低温とすることでダスト中に存在するアルカリとの反応(例えば、CaO+2HCl→CaCl2+H2O等)を促進する結果、ガス中塩素が固体状の塩類としてダスト中に付着するので同様の傾向を示すものである。
【0029】
従って、本発明にあっては、廃棄物溶融炉炉頂から排出される熱分解ガスの温度が、400℃以下になるように操業すれば、熱分解ガス中の塩類を、よりダスト中に移行させることが出来るため、排ガス中のダストを除塵器で集塵した場合、その塩類をより効果的に除去することが出来る。
【0030】
しかして、シャフト炉方式の廃棄物溶融炉にあって、熱分解ガスの温度を制御するには、供給するコークス量、下段羽口からの酸素供給割合、または、処理しようとする廃棄物の炉内の充填高さを調整することにより容易に達成することが出来る。
【0031】
但し、上述したように熱分解ガスの温度は高くない方が、塩類の多くはダスト中に含まれるというものの、150℃未満では、特に、水分割合の大きい廃棄物や、プラスチックの多い廃棄物等のタール発生割合が大きい廃棄物を処理する場合には、排ガス温度が低下し、廃棄物の温度上昇が緩やかになり、低温での熱分解により発生するタール分の割合が増大するため、充填層上部の乾燥領域での凝縮量が増大し、通気性を阻害し、ついには操業の継続を困難とするので好ましくない。
【0032】
図4は廃棄物溶融炉におけるダストの処理設備の別の例の概略図である。本例は、廃棄物溶融炉1からのダストを除塵器7で捕集する前に、廃棄物溶融炉1と除塵器7とを接続する熱分解ガスダクト3に設けた脱塩剤添加装置16で熱分解ガスに脱塩剤、例えば、消石灰を添加することにより、ガス状の塩化物を固体状の塩化物に変えて除塵器で捕集する。この結果、廃棄物溶融炉1の後流の燃焼室12、廃熱ボイラー13等の排ガス処理設備へ移行するガス状の塩化物量をさらに減少させることができる。
【0033】
図5は廃棄物溶融炉におけるダストの処理設備のさらに別の例の概略図である。ダストが捕集された熱分解ガスを処理する燃焼室12、廃熱ボイラー13、排ガス温度調節器14、集塵器15等の排ガス処理設備では、飛灰が発生するが、各装置12,13,14,15の下部からスクリューコンベア17により回収した飛灰の一部又は全部を除塵器7で捕集した可燃性ダストと洗浄槽9で混合する。飛灰中には水によって硬化する水硬性成分が含まれており、ダストに飛灰を添加することにより、脱水ケーキの強度が高まる。また、飛灰の最終処分量を減少させることもできる。
【0034】
実施例
図6は本発明の廃棄物溶融炉におけるダストの処理設備の実施例の概略図である。脱水機11からの排水を排ガス温度調節器14内のスプレーノズル18から噴霧して蒸発させることにより、系外への排水量を減少させることができる。
【0035】
【発明の効果】
(1)塩類が多く付着したダストを捕集し、脱塩処理した後、廃棄物溶融炉に再投入することにより、廃棄物溶融炉の後流の燃焼室、ボイラー等の排ガス処理設備への塩化物の移行を抑制することができるため、ボイラー腐食の主原因である塩化物の量が減少するので、従来は廃棄物中に塩化物が多いために上げられなかったボイラーの蒸気条件を上げることが可能となり、エネルギー回収効率を上昇させることができる。
【0036】
(2)従来技術では、塩化物に起因するダイオキシン類は燃焼室でほぼ完全に分解されるものの、ボイラーおよび排ガス処理系の200〜500℃の冷却過程では再合成されていたが、ボイラーおよび排ガス処理系を通過する塩化物の量が減少することにより、上記冷却過程でのダイオキシン類の再合成を抑制することが可能となる。
【図面の簡単な説明】
【図1】棄物溶融炉におけるダストの処理設備の一例を示す概略図である。
【図2】熱分解ガス単位体積当たりのガス状及び固体状の塩素重量を示すグラフである。
【図3】図2の結果より熱分解ガス温度を変化させた場合の〔固体状の塩素分〕/〔ガス状及び固体状の塩素分〕を示すグラフである。
【図4】棄物溶融炉におけるダストの処理設備の別の例の概略図である。
【図5】棄物溶融炉におけるダストの処理設備のさらに別の例を示す概略図である。
【図6】 本発明の廃棄物溶融炉におけるダストの処理設備の実施例の概略図である
【図7】一般廃棄物あるいは産業廃棄物等の廃棄物の直接溶融処理の系統図である。
【図8】一般廃棄物あるいは産業廃棄物等の廃棄物の直接溶融処理の系統図である。
【図9】一般廃棄物あるいは産業廃棄物等の廃棄物の直接溶融処理の系統図である。
[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method and apparatus for treating dust generated in a waste melting furnace that directly melts general waste, industrial waste, and the like.
[0002]
[Prior art]
Waste melting treatment, which directly melts waste in a shaft furnace type waste melting furnace, involves drying, pyrolysis, combustion, and melting processes of general waste or industrial waste charged in the waste melting furnace. Then, waste is taken out as slag and metal, and these are recycled.
[0003]
7 to 9 are system diagrams of direct melting treatment of waste such as general waste or industrial waste. The waste is charged from the top inlet of the waste melting furnace 1 and the auxiliary materials such as coke and limestone are charged into the waste melting furnace from the auxiliary material inlet. Forming.
[0004]
The waste melting furnace 1 is a shaft type furnace body having a circular cross section, and a lower tuyere 5 and an upper tuyere 6 are provided at the lower part of the furnace body, and oxygen is supplied from these tuyere 5 and 6. Enriched air or air is blown to burn the coke and waste.
[0005]
In the waste melting furnace 1, the waste is dried and preheated (about 300 ° C.), pyrolyzed (300 to 1000 ° C.), and burned and melted (1700 to 1800 ° C.) due to combustion of waste pyrolysis residue and coke. Through this process, it becomes a melt of metal and slag, and is subjected to water granulation, separating the metal and slag with a magnetic separator, and recycling them.
[0006]
In the waste melting furnace 1, the combustible matter in the charge is pyrolyzed to generate a residue (char), which is burned by the air sent from the tuyere 6, and the ash is melted to form slag. However, the fine particles are not burned by the air sent from the tuyere 6, but are scattered as flammable dust from the furnace by the airflow.
[0007]
Conventionally, the pyrolysis gas containing the combustible dust scattered in the waste melting furnace 1 is sent to the combustion chamber 12 as it is without passing through the dust remover 7 such as a cyclone as shown in FIG. As shown in Fig. 9, even when a dust remover 7 such as a cyclone is provided, the collected combustible dust includes a hopper for storing the combustible dust, a device for quantitatively cutting out the stored combustible dust, and further pyrolysis. It was mixed with the pyrolysis gas through a device that uniformly disperses in the gas, and it was also sent to the combustion chamber 12 for combustion.
[0008]
The combustion exhaust gas (800 to 900 ° C.) generated by the combustion is sent to the waste heat boiler 13 for heat recovery, and is discharged to the atmosphere through the exhaust gas temperature controller 14 and the dust collector 15.
[0009]
As a processing technique for combustible dust scattered from a waste melting furnace, the present applicant, in Japanese Patent Application Laid-Open No. 7-88462, collects scattered combustible dust, blows the collected dust from a tuyere, and uses it as a heat source. We have proposed a technology to reduce auxiliary fuel such as coke, which is a heat source for drying and melting waste by reuse. In this technique, as shown in FIG. 7, after the flammable dust collected by the dust remover 7 is temporarily stored in the flammable dust hopper 8, a predetermined amount is cut out and blown into the furnace from the tuyere 6. Thus, the combustible component in the dust can be used as a heat source for the waste melting furnace 1, so that coke as auxiliary fuel can be reduced.
[0010]
However, since the chloride generated in the waste melting furnace adheres to the combustible dust, when the combustible dust collected by the dust remover is blown into the furnace from the tuyere, the chloride attached to the combustible dust is again It is blown into the waste melting furnace, gasifies and re-scatters under the high temperature condition in the furnace, moves to the combustion chamber, boiler, and exhaust gas treatment facility downstream of the waste melting furnace and corrodes the boiler piping and the like.
[0011]
In waste treatment, in order to prevent corrosion of boiler piping and the like by chlorides, for example, Japanese Patent Laid-Open No. 4-121511 discloses that a reactive agent is added to pyrolysis gas generated in a waste pyrolysis furnace. A waste gas treatment device is described in which clean gas supplied and dust-removed by a filter is introduced into the boiler, and the reaction products and fly ash removed by the filter are regenerated by the fly ash regeneration device and sent again to the reactor along with the reactants. Has been.
[0012]
Japanese Patent Application Laid-Open No. 9-89227 discloses a gas containing chlorine generated in a pyrolysis furnace, recovering heat in a secondary combustion chamber, melting a residue generated in the pyrolysis furnace, and exhaust gas not containing chlorine. Describes a waste pyrolysis melting system for increasing the temperature and pressure of steam generated in a waste heat boiler.
[0013]
[Problems to be solved by the invention]
However, in the waste treatment apparatus described in JP-A-4-121511, the reaction products and fly ash removed by the filter are regenerated by the fly ash regeneration apparatus and are again circulated to the reactor together with the reactants. Chloride does not escape from the system and is incomplete as a system.
[0014]
In addition, the waste pyrolysis melting system described in Japanese Patent Laid-Open No. 9-89227 has three facilities for combusting waste, a pyrolysis furnace, a secondary combustion chamber, and a melting furnace. Since the exhaust gas containing chlorine flows into the waste heat boiler at the downstream of the secondary combustion chamber, dioxins are re-synthesized in the process where the exhaust gas is cooled to 500 ° C to 300 ° C in the boiler part. . Moreover, since heat recovery is performed after the high-temperature exhaust gas from the waste melting furnace is mixed with the boiler low-temperature gas, the heat transfer efficiency also deteriorates.
[0015]
The present invention prevents corrosion of boiler piping and the like by chloride by removing chloride from pyrolysis gas containing combustible dust generated in a waste melting furnace that directly melts waste, and removes cooling of the boiler. The present invention provides a dust processing method and an apparatus for preventing dioxin resynthesis in the process.
[0016]
[Means for Solving the Problems]
The dust processing method in the waste melting furnace of the present invention collects dust before entering the combustion chamber from pyrolysis gas containing combustible dust scattered from a shaft furnace type waste melting furnace that directly melts the waste. The salt in the collected dust is extracted with water and then dehydrated. The dehydrated extract is sprayed into the exhaust gas temperature controller to evaporate it, and the dehydrated cake after dehydration is re-introduced into the waste melting furnace. It is characterized by doing.
[0017]
In addition, the dust processing facility in the waste melting furnace according to the present invention includes a dust remover provided in a pyrolysis gas duct that guides the pyrolysis gas generated from the shaft furnace type waste melting furnace to the combustion chamber, and is collected by the dust remover. An extractor that extracts salt from the collected dust with water, a dehydrator that separates solids from the extract, and a waste heat boiler with a superheated steam generator, and an exhaust gas temperature controller that evaporates the dehydrated extract A spray nozzle or a disk atomizer is provided .
[0018]
DETAILED DESCRIPTION OF THE INVENTION
In the method for treating dust containing combustible dust according to the present invention, before collecting dust from the pyrolysis gas of the waste melting furnace, a desalting agent is added to the pyrolysis gas with a desalting agent addition device. By solidifying this chloride, gaseous hydrogen chloride can be changed to solid chloride and collected by a dust remover. As a result, a waste heat boiler can be provided in the exhaust gas with less chloride.
[0019]
In addition, fly ash collected from exhaust gas treatment equipment such as combustion chambers, waste heat boilers, exhaust gas temperature controllers, and dust collectors that process pyrolysis gas from which combustible dust is collected is mixed with the collected dust. As a result, the strength of the dehydrated cake is increased, and the final disposal amount of fly ash can be reduced.
[0020]
Further, the amount of drainage to the outside of the system can be eliminated or reduced by spraying and evaporating the extract generated from the dehydrator into the exhaust gas temperature controller.
[0021]
FIG. 1 is a schematic view showing an example of dust processing equipment in a waste melting furnace . The shaft furnace type waste melting furnace 1 that directly melts waste is not different from the conventional waste melting furnace described above, and is a double seal for charging waste, coke, and limestone in the upper part of the furnace. The charging device 2 of the valve mechanism, the pyrolysis gas duct 3 for exhausting the pyrolysis gas are provided, the outlet 4 for discharging the slag, the oxygen-enriched air in which air and oxygen are mixed at the lower part of the furnace A lower tuyere 5 for blowing air and an upper tuyere 6 for blowing air are provided.
[0022]
The dust stored in the dust hopper 8 is put into a washing bowl 9 containing water, and stirred with a stirrer 10 to promote the reaction, and washed with water. Water-soluble components such as chlorides and sulfates are eluted in water by washing with water. Thereafter, the cleaning liquid is dehydrated by the dehydrator 11 and separated into a dehydrated cake with less salt and drainage from which the salt has eluted. Wastewater containing salts is detoxified and released.
[0023]
The dehydrated cake from which the salts have been removed is re-introduced from the top of the waste melting furnace 1, combustible components in the dehydrated cake are pyrolyzed and gasified in the waste melting furnace, and the slag component is melted into slag.
[0024]
The combustible gas from which the combustible dust to which the salt has adhered is removed by the dust remover 7 is sent to the combustion chamber 12 to be combusted, and the exhaust gas generated by the combustion is sent to the waste heat boiler 13 for heat recovery, and the exhaust gas temperature controller. After cooling with 14 and collecting with the bag filter 15, it is discharged to the atmosphere. Fly ash from the combustion chamber 12, the waste heat boiler 13 and the exhaust gas temperature controller 14 is kneaded and granulated and charged into a waste melting furnace, and the dust collection ash of the bag filter 15 is detoxified.
[0025]
The inventors pay attention to the behavior of the chlorine content in the pyrolysis gas containing combustible dust in this example , change the temperature of the pyrolysis gas generated from the waste melting furnace 1, and change the chlorine in the pyrolysis gas. The amount of gaseous and solid chlorine contained in the pyrolysis gas was investigated by measuring the concentration, dust concentration, and chlorine content in the dust.
[0026]
FIG. 2 shows the weights of gaseous and solid chlorine per unit volume of pyrolysis gas. Further, from this result, [solid chlorine content] / [gaseous gas] when the pyrolysis gas temperature is changed. And solid chlorine content] are shown in FIG.
[0027]
As is clear from this figure, when the temperature of the pyrolysis gas is around 400 ° C. or less, the chlorine content in the pyrolysis gas is contained more in the solid, that is, in the dust than in the gaseous state.
[0028]
This is because the pyrolysis gas generated from the waste melting furnace contains chlorine that exists as low-boiling point (sublimation point) salts such as ammonium chloride (sublimation point 338 ° C.). However, it seems to adhere to dust as solid salts. Further, even when HCl is present in the pyrolysis gas, the reaction with the alkali present in the dust (for example, CaO + 2HCl → CaCl 2 + H 2 O, etc.) is promoted by lowering the gas temperature. Since chlorine adheres in the dust as solid salts, the same tendency is exhibited.
[0029]
Therefore, in the present invention, if the operation is performed so that the temperature of the pyrolysis gas discharged from the top of the waste melting furnace becomes 400 ° C. or less, the salts in the pyrolysis gas are transferred to the dust more. Therefore, when dust in exhaust gas is collected by a dust remover, its salts can be removed more effectively.
[0030]
In a shaft furnace type waste melting furnace, in order to control the temperature of the pyrolysis gas, the amount of coke to be supplied, the oxygen supply rate from the lower tuyere, or the furnace of the waste to be treated It can be easily achieved by adjusting the filling height inside.
[0031]
However, as mentioned above, when the temperature of the pyrolysis gas is not high, most of the salts are contained in the dust. However, when the temperature is lower than 150 ° C., especially waste with a high water content, waste with a lot of plastic, etc. When processing waste with a large tar generation rate, the exhaust gas temperature decreases, the temperature rise of the waste becomes moderate, and the rate of tar content generated by thermal decomposition at low temperature increases. This is not preferable because the amount of condensation in the upper drying region increases, impairs air permeability, and finally makes it difficult to continue the operation.
[0032]
FIG. 4 is a schematic view of another example of dust processing equipment in a waste melting furnace . In this example , before the dust from the waste melting furnace 1 is collected by the dust remover 7, the desalting agent addition device 16 provided in the pyrolysis gas duct 3 connecting the waste melting furnace 1 and the dust remover 7 is used. By adding a desalting agent such as slaked lime to the pyrolysis gas, the gaseous chloride is changed to a solid chloride and collected by a dust remover. As a result, it is possible to further reduce the amount of gaseous chloride transferred to the exhaust gas treatment equipment such as the combustion chamber 12 and the waste heat boiler 13 in the downstream of the waste melting furnace 1.
[0033]
FIG. 5 is a schematic view of still another example of dust processing equipment in a waste melting furnace . In the exhaust gas treatment equipment such as the combustion chamber 12, the waste heat boiler 13, the exhaust gas temperature controller 14, and the dust collector 15 that process the pyrolysis gas in which dust is collected, fly ash is generated. , 14 and 15, part or all of the fly ash collected by the screw conveyor 17 is mixed in the washing tank 9 with the combustible dust collected by the dust remover 7. The fly ash contains a hydraulic component that is hardened by water, and the strength of the dehydrated cake is increased by adding fly ash to the dust. Moreover, the final disposal amount of fly ash can also be reduced.
[0034]
Embodiment FIG. 6 is a schematic view of an embodiment of the dust treatment facility in the waste melting furnace of the present invention. By spraying the waste water from the dehydrator 11 from the spray nozzle 18 in the exhaust gas temperature controller 14 and evaporating it, the amount of waste water to the outside of the system can be reduced.
[0035]
【The invention's effect】
(1) Dust with a large amount of salt attached is collected, desalted, and then re-introduced into the waste melting furnace, so that it can be sent to the exhaust gas treatment equipment such as the combustion chamber and boiler behind the waste melting furnace. Since the migration of chloride can be suppressed, the amount of chloride, which is the main cause of boiler corrosion, is reduced, so the steam conditions of boilers that could not be raised due to the high amount of chloride in the waste are increased. Energy recovery efficiency can be increased.
[0036]
(2) In the prior art, although dioxins resulting from chlorides are almost completely decomposed in the combustion chamber, they were re-synthesized in the cooling process of the boiler and exhaust gas treatment system at 200 to 500 ° C., but the boiler and exhaust gas By reducing the amount of chloride passing through the treatment system, it is possible to suppress the resynthesis of dioxins during the cooling process.
[Brief description of the drawings]
1 is a schematic diagram showing an example of a dust treatment facility in waste melting furnace.
FIG. 2 is a graph showing the weight of gaseous and solid chlorine per unit volume of pyrolysis gas.
3 is a graph showing [solid chlorine content] / [gaseous and solid chlorine content] when the pyrolysis gas temperature is changed from the results of FIG.
Figure 4 is a schematic diagram of another example of the dust of the processing equipment in waste melting furnace.
5 is a schematic diagram showing still another example of the dust of the processing equipment in waste melting furnace.
FIG. 6 is a schematic diagram of an embodiment of a dust treatment facility in the waste melting furnace of the present invention. FIG. 7 is a system diagram of direct melting treatment of waste such as general waste or industrial waste.
FIG. 8 is a system diagram of direct melting treatment of waste such as general waste or industrial waste.
FIG. 9 is a system diagram of direct melting treatment of waste such as general waste or industrial waste.

Claims (6)

廃棄物を直接溶融するシャフト炉方式の廃棄物溶融炉から飛散する可燃性ダストを含む熱分解ガスからダストを燃焼室に入る前に捕集し、捕集したダスト中の塩類を水で抽出した後脱水し、脱水した抽出液を排ガス温度調節器内に噴霧して蒸発させるとともに、前記脱水後の脱水ケーキを廃棄物溶融炉に再投入することを特徴とする廃棄物溶融炉におけるダストの処理方法。Dust is collected before entering the combustion chamber from pyrolysis gas containing combustible dust scattered from a shaft furnace type waste melting furnace that directly melts waste, and salts in the collected dust are extracted with water. after de water, dehydrated extracts with evaporated by spraying into the exhaust gas temperature controller, the dust in the waste melting furnace, characterized in that repopulate the dehydrated cake after the dehydration waste melting furnace Processing method. 廃棄物を直接溶融するシャフト炉方式の廃棄物溶融炉から飛散する可燃性ダストを含む熱分解ガスの、炉頂排出時の温度が、150〜400℃となるように炉の操業を行うことを特徴とする請求項1記載の廃棄物溶融炉におけるダストの処理方法。To operate the furnace so that the temperature at the top discharge of the pyrolysis gas containing combustible dust scattered from the shaft furnace type waste melting furnace that melts the waste directly becomes 150-400 ° C. The method for treating dust in the waste melting furnace according to claim 1, wherein: 廃棄物を直接溶融するシャフト炉方式の廃棄物溶融炉から飛散する可燃性ダストを含む熱分解ガスからダストを捕集する前に、熱分解ガスに消石灰またはCaOの脱塩剤を添加してガス状の塩化物を固体化することを特徴とする請求項1又は2記載の廃棄物溶融炉におけるダストの処理方法。Before collecting dust from pyrolysis gas containing combustible dust scattered from a shaft furnace type waste melting furnace that directly melts waste, gas is added to the pyrolysis gas by adding slaked lime or CaO desalting agent The method for treating dust in a waste melting furnace according to claim 1 or 2, wherein said chloride is solidified. 可燃性ダストが捕集された後の熱分解ガスを処理する燃焼室、廃熱ボイラー、排ガス温度調節器、集塵器等の排ガス処理設備から回収した飛灰を捕集した可燃性ダストと混合し、塩類を水で抽出することを特徴とする請求項1ないし3のいずれかの項に記載の廃棄物溶融炉におけるダストの処理方法。Mixing with flammable dust collected fly ash collected from exhaust gas treatment equipment such as combustion chamber, waste heat boiler, exhaust gas temperature controller, dust collector, etc., which processes pyrolysis gas after flammable dust is collected 4. The method for treating dust in a waste melting furnace according to claim 1, wherein the salt is extracted with water. シャフト炉方式の廃棄物溶融炉から発生する熱分解ガスを燃焼室に導く熱分解ガスダクトに設けた除塵器と、除塵器で捕集したダスト中の塩類を水で抽出する抽出器と、固形分と抽出液を分離する脱水器と廃熱ボイラーに過熱蒸気の発生器を設けるとともに、排ガス温度調節器に脱水した抽出液を蒸発するためのスプレーノズル又はディスクアトマイザーを設けたことを特徴とする廃棄物溶融炉におけるダストの処理装置。 A dust remover installed in the pyrolysis gas duct that guides the pyrolysis gas generated from the shaft furnace waste melting furnace to the combustion chamber, an extractor that extracts salt from the dust collected by the dust remover with water, and a solid content Disposer characterized by having a dehydrator for separating the extract and the waste heat boiler, a superheated steam generator, and a spray nozzle or disk atomizer for evaporating the dehydrated extract in the exhaust gas temperature controller Dust processing equipment in a material melting furnace. シャフト炉方式の廃棄物溶融炉と除塵器とを接続する熱分解ガスダクトに消石灰またはCaOの脱塩剤を添加する脱塩剤添加装置を設けたことを特徴とする請求項記載の廃棄物溶融炉におけるダストの処理装置。 6. A waste melting apparatus according to claim 5, further comprising a desalting agent addition device for adding slaked lime or a CaO desalting agent to a pyrolysis gas duct connecting a shaft furnace type waste melting furnace and a dust remover. Dust processing equipment in the furnace.
JP17513998A 1997-12-02 1998-06-22 Method and apparatus for treating dust in waste melting furnace Expired - Fee Related JP4039647B2 (en)

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JP33213197 1997-12-02
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JP4542417B2 (en) * 2004-11-26 2010-09-15 新日鉄エンジニアリング株式会社 Method of treating combustible gas in waste melting furnace
JP4881279B2 (en) * 2007-11-06 2012-02-22 新日鉄エンジニアリング株式会社 Waste gas melting furnace gas pipe and cyclone dust adhesion prevention method and apparatus
JP5198409B2 (en) * 2009-11-04 2013-05-15 大同特殊鋼株式会社 Treatment method of exhaust gas dust
JP5704427B2 (en) * 2010-06-30 2015-04-22 住友大阪セメント株式会社 Thermal decomposition apparatus, dechlorination treatment apparatus, thermal decomposition method and dechlorination method
JP5767938B2 (en) * 2011-10-19 2015-08-26 新日鉄住金エンジニアリング株式会社 Volume reduction method for low-level radioactive waste
JP6180983B2 (en) * 2014-03-28 2017-08-16 住友重機械工業株式会社 Combustion apparatus, operation method of combustion apparatus, and ash circulation system
CN106475398B (en) * 2016-10-12 2018-09-14 辽宁东大粉体工程技术有限公司 A kind of industrial waste salt carbonization treatment method
CN111380060A (en) * 2020-03-21 2020-07-07 深圳市海文环保技术有限公司 Chemical waste salt harmless treatment system and method

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