JP3717226B2

JP3717226B2 - Incinerator dust treatment equipment

Info

Publication number: JP3717226B2
Application number: JP06909796A
Authority: JP
Inventors: 英雄岩崎; 好人船渡; 郁夫加納; 一男大隅; 彰啓伊藤
Original assignee: Takuma KK
Current assignee: Takuma KK
Priority date: 1995-02-28
Filing date: 1996-02-28
Publication date: 2005-11-16
Anticipated expiration: 2016-02-28
Also published as: JPH0919675A

Description

【０００１】
【発明の属する技術分野】
本発明は一般廃棄物や産業廃棄物の焼却炉において、焼却炉から排出される廃棄物のうち、ばいじん（電気集塵機やバグフィルタなどの集塵施設によって集められたものに限らず、ボイラーダストでの飛灰や溶融炉での飛灰なども含む意味で使用する。）を一般廃棄物として処分できるようにしたり、又は再利用できるようにするための中間処理を施す装置に関するものである。
【０００２】
【従来の技術】
ばいじんは廃棄物の処理及び清掃に関する法律（廃棄物処理法）の改正法により特別管理一般廃棄物に指定され、厚生大臣の定める次の４つの方法の何れかによって中間処理を施さなければ一般廃棄物として埋め立て処分などをすることができない（厚生省告示第１９４号）。
（１）溶融固化
（２）セメント固化
（３）薬剤処理
（４）酸その他の溶媒による安定化
【０００３】
ごみが千数百度という高温度で焼却される際、ごみ中の重金属の一部はその高温によって揮散（蒸発）するが、集塵されることによって冷却され、固体に戻る。そのため、ばいじん中には重金属が多く含まれている。ばいじんを埋め立て処分した際ばいじんに含まれている重金属が溶出しないようにするのが上記の中間処理の目的である。
上記の中間処理方法のうち、薬剤処理法は設備面、維持管理面、技術の確立の面において優れている。
【０００４】
中間処理されたばいじん中の鉛、カドミウム、六価クロム、砒素、水銀及びセレンの重金属に関して溶出基準が定められており、処分するためにはその基準を満たさなければならない。
ばいじん中に含まれる塩化水素を処理するために、排ガスラインには消石灰が添加される。ばいじんを１０％水溶液とした場合、通常のばいじんのｐＨは９程度であるが、消石灰注入後のばいじん水溶液では１１〜１３程度となる。
中間処理されたばいじん中の鉛は、ｐＨが１０程度のとき最も溶出しにくく、ｐＨがそれよりも高くなっても低くなっても溶出し易くなることが知られている。消石灰を含むアルカリ剤により排ガス処理を行なっている焼却設備において発生するばいじん（以下、アルカリ飛灰という）では、その水溶液のｐＨが高いため、鉛の溶出が著しい。
【０００５】
一方、アルカリ剤による排ガス処理を行なっていない焼却設備において発生するばいじん（以下、中性飛灰という）は、その水溶液のｐＨが６〜１０程度を示すため、鉛及びカドミウムが溶出基準以上に検出されることがある。
そのため、薬剤処理法では重金属が溶出しにくくなる重金属安定剤として液体キレートを添加するとともに、ｐＨ調整剤によりｐＨ調整を行なっている。
【０００６】
法に定められた方法によれば、中間処理されたばいじんからの重金属溶出量は、処理物を６時間かけて水に溶出させ、その上澄み液に酸処理及び溶媒抽出などの処理を施した後、原子吸光分析により測定する。したがって、このように長時間を要する分析の結果をばいじんの処理装置にフィードバックさせても、時間遅れが大きすぎてばいじんの性状が変化してしまっていることがあり、安定な中間処理を行なうことはできない。そのため、ばいじんの性状が変化しても重金属溶出量が基準からはみ出すことがないような一定量の液体キレートなどの重金属安定剤を添加している。
【０００７】
中間処理後のｐＨを１０付近に設定するだけによっても重金属の溶出を規定範囲内に抑えることができる場合もある。その場合も、ばいじん及びその処理物は固体であるため、そのｐＨ値は容易に測定することができない。そのため、現在は一定量のｐＨ調整剤を注入している。
【０００８】
【発明が解決しようとする課題】
一定量に設定された重金属安定剤を添加する方法では、ばいじん中の重金属量が少ない場合には重金属安定剤を必要以上に消費することになり、費用の無駄を生じるとともに、廃棄物の量を必要以上に大きくする問題が生じる。
【０００９】
一定量のｐＨ調整剤を注入する方法では、排ガス中のＨＣｌ量によって注入される消石灰量が変わるため、中間処理後のばいじんのｐＨはたえず変化する。したがって、中間処理後のばいじんが常に重金属が溶出しにくいｐＨ値になっている保証がない。
【００１０】
本発明の第１の目的は、ばいじんの処理物のｐＨが重金属の溶出しにくい値になるようにｐＨ調整剤の添加量を制御できるようにした処理装置を提供することである。
本発明の第２の目的は、重金属安定剤の無駄な添加を防ぎ、かつ規定の重金属溶出値を満たす処理装置を提供することである。
本発明の第３の目的は、ばいじんの処理物のｐＨが重金属の溶出しにくい値になるようにｐＨ調整剤の添加量を制御でき、かつ重金属安定剤の無駄な添加を防ぎ、しかも規定の重金属溶出値を満たす処理装置を提供することである。
【００１１】
【課題を解決するための手段】
本発明のばいじん処理装置は、焼却炉のばいじんに水又はさらにセメントも添加して処理する混練装置にｐＨ調整剤を添加するｐＨ調整剤添加部と重金属安定剤を添加する重金属安定剤添加部の少なくとも一方を備えている。ｐＨ調整剤添加量や重金属安定剤添加量を制御するために、混練装置による処理前又は処理後のばいじんの一定量を採取する採取部と、採取されたばいじんに一定量の水を添加して撹拌し、ばいじんに含有されている成分を数分〜数十分で溶出させる溶出部と、ｐＨ調整剤添加量制御用に溶出部からの溶出液のＰ−アルカリ度もしくはカルシウム溶出量、酸度又はｐＨを測定するアルカリ度・酸度測定部、及び重金属安定剤添加量制御用に溶出部からの溶出液の少なくとも鉛を含む重金属溶出量を測定する重金属測定部のうちの少なくとも一方を備えている測定部と、制御部とを備えている。
【００１２】
重金属測定部を備えた場合に、鉛やカドミウムを溶出しやすくするために、溶出部でばいじんに添加する水として一定のｐＨ値に調製された水を使用することができる。また、水を添加した後、さらに酸又はアルカリを添加してｐＨ値を一定に制御してもよい。添加する水のｐＨ値又は溶出部でのｐＨ値を酸性側にするために、硫酸、硝酸、塩酸、酢酸などを使用することができる。添加する水のｐＨ値又は溶出部でのｐＨ値をアルカリ性側にするために、カセイソーダや水酸化カルシウムなどを使用することができる。
【００１３】
重金属測定部を備えた場合に、鉛やカドミウムを溶出しやすくするために、水の他にさらに重金属と水溶性化合物を生成する溶出剤を添加してもよい。そのような溶出剤としては、クエン酸や蓚酸を使用することができ、炭酸ガスを吹き込んでもよい。
混練装置の語は、ばいじんに水又はさらにセメントも添加し混合して出す調湿装置、混合を目的とした装置、及び成形機の全てを含む意味で使用している。
【００１４】
制御部は図１に示された機能を果たす。制御部２は、薬液添加量算出部６及び薬液添加制御部８を含み、処理前のばいじんの溶出液を測定する場合にはさらに薬液添加量データ記憶部４も含む。
混練装置による処理前のばいじんの溶出液を測定して制御する場合は、ｐＨ調整剤添加量の制御のためには、薬液添加量データ記憶部４はＰ−アルカリ度もしくはカルシウム溶出量、酸度又はｐＨに対するｐＨ調整剤添加量のデータを記憶しており、薬液添加量算出部６は薬液添加量データ記憶部４のデータに従い、アルカリ度・酸度測定部での測定値に対応したｐＨ調整剤添加量を算出する。薬液添加制御部８はｐＨ調整剤添加部からのｐＨ調整剤添加量が薬液添加量算出部６でのｐＨ調整剤添加量の算出量となるようにｐＨ調整剤添加部の動作を制御する。重金属安定剤添加量の制御のためには、薬液添加量データ記憶部４は重金属溶出量に対する重金属安定剤添加量のデータを記憶しており、薬液添加量算出部６は薬液添加量データ記憶部４のデータに従い、重金属測定部での測定値に対応した重金属安定剤添加量を算出する。薬液添加制御部８は重金属安定剤添加部からの重金属安定剤添加量が薬液添加量算出部での算出量となるように重金属安定剤添加部の動作を制御する。ｐＨ調整剤添加量と重金属安定剤添加量の両方を制御するためには、各部４，６，８は両薬液添加のための両方の機能を果たす。
【００１５】
混練装置による処理後のばいじんの溶出液を測定して制御する場合は、ｐＨ調整剤添加量の制御のためには、そのばいじんがアルカリ飛灰である場合には、適当な薬液注入量で開始した後、薬液添加量算出部６は２回目以降の添加量として、アルカリ度測定部での測定値が所定値以上である場合は次回のｐＨ調整剤添加量を前回よりも増量し、所定値未満である場合は前回のＰ−アルカリ度又はカルシウム溶出量と比較し、前回の測定値より増加していれば次回のｐＨ調整剤添加量を前回と同じとし、増加していなければ前回よりも減量するようにｐＨ調整剤添加量を算出する。薬液添加制御部８はｐＨ調整剤添加部からのｐＨ調整剤添加量が薬液添加量算出部６での算出量となるようにｐＨ調整剤添加部の動作を制御する。重金属安定剤添加量の制御のためには、適当な薬液注入量で開始した後、薬液添加量算出部６は２回目以降の添加量として、重金属測定部での測定値が所定の値以上であれば前回の重金属安定剤添加量よりも増量し、所定値未満で前回の測定値と同一又は減少しておれば前回の重金属安定剤添加量よりも減量し、所定値未満で前回の測定値よりも増加しておれば前回の重金属安定剤添加量と同量とするように重金属安定剤添加量を算出する。薬液添加制御部８は重金属安定剤添加部からの重金属安定剤添加量が薬液添加量算出部６での算出量となるように重金属安定剤添加部の動作を制御する。この場合にもｐＨ調整剤添加量と重金属安定剤添加量の両方を制御するためには、薬液添加量算出部６と薬液添加制御部８は両薬液添加のための両方の機能を果たす。
【００１６】
Ｐ−アルカリ度もしくはカルシウム溶出量、酸度又はｐＨを測定してｐＨ調整剤添加量を制御する部分と、少なくとも鉛を含む重金属の濃度を測定して重金属安定剤の添加量を制御する部分は、何れか一方のみを備えていてもよく、両方を備えてｐＨ調整剤と重金属安定剤の両方を添加するようにしてもよい。
アルカリ度・酸度測定部は、処理対象のばいじんがアルカリ飛灰の場合にはＰ−アルカリ度もしくはカルシウム溶出量を測定するアルカリ測定部となる。Ｐ−アルカリ度はＪＩＳ規格Ｋ０１０１の用水試験に規定されたものであり、Ｐ−アルカリ度を自動的に測定するために自動適定装置が市販されている。本発明でのＰ−アルカリ度測定にはそのような自動適定装置を用いることができる。
【００１７】
また、アルカリ度・酸度測定部は、処理対象のばいじんが中性飛灰の場合には酸度を測定する酸度測定部となる。酸度測定にもＰ−アルカリ度測定と同様の自動適定装置を用い、滴定試薬としてカセイソーダ溶液などのアルカリ溶液を使用して実施することができる。
カルシウム溶出量は原子吸光光度計で測定することができる。
ｐＨはｐＨメータで測定することができ、ｐＨ値に応じてｐＨ調製剤添加量を制御してもよい。
【００１８】
測定する重金属には鉛、カドミウム、六価クロム、砒素、水銀及びセレンがある。重金属のうち最も多く含まれるのは鉛であるが、鉛以外にも地域によっては水銀やカドミウムが多く含まれる地域もある。地域によって、測定する重金属の種類を鉛だけにしたり、鉛と水銀やカドミウムその他の重金属も含めて行なうようにしてもよい。これらの重金属の濃度は、原子吸光光度計で光源として測定対象金属を用いた中空陰極ランプを使用することにより測定することができる。これらの重金属の濃度測定のためにはまた、原子吸光光度計に代えてＩＣＰ（誘導結合プラズマ）装置を用いることもできる。
ｐＨ調整剤としては、アルカリ飛灰に対しては硫酸バンド、ポリ鉄、塩化第２鉄などの水溶液を用い、中性飛灰に対してはカセイソーダ、水酸化カルシウム、水酸化マグネシウムなどのアルカリ溶液を用いることができる。
重金属安定剤としては液体キレート、無機系処理剤などを用いることができる。
【００１９】
ばいじんの溶出が短時間で可能であるかどうかを調べるために、混練装置による処理前のばいじんを水で希釈溶出した結果を図２〜図４に示す。それぞれ１０倍、１００倍、１０００倍に希釈した水溶液について測定したものであり、図２はＰ−アルカリ度、図３はカルシウム溶出量、図４は鉛溶出量をそれぞれ測定したものである。Ｐ−アルカリ度、カルシウム溶出量、鉛溶出量は焼却設備によって異なるが、ともに数分〜数十分間の溶出でほぼ平衡状態となっている。
【００２０】
液体キレートを添加し混練装置で処理した直後のばいじんを同様に測定した結果を図５、図６に示す。図５はＰ−アルカリ度、図６は鉛溶出量をそれぞれ測定したものである。この場合も、Ｐ−アルカリ度、鉛溶出量ともに数分〜数十分間の溶出でほぼ平衡状態となっており、カルシウム溶出量の測定結果は示していないが、同様の結果が得られている。
希釈倍率が１０００倍を超えてあまり大きくなった場合には装置が過大になる虞れがあるので、１０〜１０００倍希釈程度が適当である。
【００２１】
ばいじんがアルカリ飛灰である場合、処理される前のばいじんの溶出液から自動適定装置により測定されたＰ−アルカリ度に基づいてｐＨ調整剤添加量を制御する動作を図７〜１０により説明する。
制御装置２の薬液添加量データ記憶部４には図８，９に示されるようなＰ−アルカリ度に対するｐＨ調整剤（例えば硫酸バンド）の添加量を示すデータが記憶されている。図８は１０倍希釈の場合、図９は５００倍希釈の場合である。自動適定装置によりＰ−アルカリ度が測定されると、薬液添加量算出部６がｐＨ調整剤の添加量を算出し、薬液添加制御部８がｐＨ調整剤添加部からの供給流量を制御してｐＨ調整剤を混練装置に添加する。
【００２２】
Ｐ−アルカリ度の代りに原子吸光光度計によりカルシウム溶出量を測定してもよい。その場合、薬液添加量データ記憶部４には図１０に示されるようなカルシウム溶出量に対するｐＨ調整剤（例えば硫酸バンド）添加量を示すデータが記憶されており、このデータに基づいてｐＨ調整剤の添加量が調整される。
ばいじんが中性飛灰である場合はＰ−アルカリ度の代りに酸度を測定する。その場合、薬液添加量データ記憶部４には図８〜１０のデータに代わるものとして、酸度測定値に対するｐＨ調整剤としてのアルカリ溶液添加量を示すデータが記憶される。その場合も動作は同じであり、自動適定装置により酸度が測定されると、薬液添加量算出部６がｐＨ調整剤の添加量を算出し、薬液添加制御部８がｐＨ調整剤添加部からの供給流量を制御してｐＨ調整剤を混練装置に添加する。
【００２３】
処理される前のばいじんの溶出液から原子吸光光度計によって測定された重金属溶出量（一例として鉛溶出量）の信号に基づいて重金属安定剤としての液体キレート添加量を制御する動作を図７と図１１により説明する。制御部２の薬剤添加量データ記憶部４には図１１に示されるような鉛溶出量と液体キレート添加量を示すデータが記憶されており、鉛溶出量が測定されると、その測定値に基づいて薬液添加量算出部６が液体キレート添加量を算出し、薬液添加制御部８が重金属安定剤添加部からの供給流量を調整して所定量の液体キレートを混練装置に添加する。
【００２４】
混練装置で処理された後のばいじんの溶出液を用いて制御を行なう場合の動作を図１２に示す。この場合は、処理後のばいじん中のＰ−アルカリ度、カルシウム溶出度もしくはｐＨ、又は鉛その他の重金属溶出量が所定の値になるように制御する。
【００２５】
ばいじんがアルカリ飛灰である場合に、Ｐ−アルカリ度を低下させるｐＨ調整剤の添加量を制御する場合を説明すると、混練装置には最初、適当に設定された量のｐＨ調整剤を添加する。そして、混練装置での処理直後のばいじんの溶出液から自動適定装置によりＰ−アルカリ度を測定し、または原子吸光光度計によりカルシウム溶出量を測定する。鉛などの重金属が溶出しにくい所定の値に対して、その測定値に対応するｐＨ値がその所定の値以上である場合は、前回の添加量は足りなかったことになるので、次回のｐＨ調整剤添加量を前回よりも増量する。所定値未満である場合は前回のＰ−アルカリ度又はカルシウム溶出量と比較し、前回の測定値より増加していれば前回の添加量は適量に近づいているので次回のｐＨ調整剤添加量を前回と同じとし、増加していなければ所定の値に近づけるために前回よりも減量する。Ｐ−アルカリ度又はカルシウム溶出量の測定が最初のものである場合は、そのＰ−アルカリ度又はカルシウム溶出量が所定値未満であっても、前回のＰ−アルカリ度又はカルシウム溶出量と比較できないので、ｐＨ調整剤添加量は前回（最初のもの）と同じにしておく。
【００２６】
ばいじんが中性飛灰である場合はＰ−アルカリ度の代りに酸度を測定し、図１２と同様に制御する。
原子吸光光度計による鉛その他の重金属溶出量を測定したときも重金属安定剤の添加量の制御は図１２に示された通りである。
このように、混練装置で処理された後のばいじんの溶出液を用いて制御を行なえば、ｐＨ調整剤や重金属安剤の無駄な添加を防ぐことができる。
【００２７】
【実施例】
図１３は一実施例を表わす。
１０はばいじんサイロであり、ごみ焼却炉の電気集塵機で集められたばいじんが収容される。ばいじんサイロ１０に収容されたばいじんは、その底部から混練装置１２へ取り出される。混練装置１２にはばいじんを固化させるために水が添加される。ばいじんには既に消石灰が添加されているので、水を添加するだけで固化するが、さらにセメントを添加してもよい。混練装置１２には、さらにｐＨ調整剤供給部１４からのｐＨ調整剤と重金属安定剤供給部１８からの重金属安定剤のうちの何れか、又は両方が添加される。ｐＨ調整剤の添加量と重金属安定剤の添加量は、制御装置２により制御されたそれぞれの供給用ポンプ１６，２０により制御される。混練装置１２で固化された処理後のばいじん２２は、一般廃棄物として埋め立て処分などがなされる。
【００２８】
ばいじんサイロ１０からの処理前のばいじんの一定量を採取するために、ばいじんサイロ１０にはねじ式ポンプなどのポンプ２４が設けられ、ポンプ２４で引き抜かれたばいじんが循環パイプ２６によって再びばいじんサイロ１０へ戻る循環流路が設けられている。その循環パイプ２６の下端部には循環パイプを移動中のばいじんを取り出すバルブ２８が設けられている。そのバルブ２８の下部には、バルブ２８から供給されるばいじんを受けるホッパーを備えて、ばいじんを計量する計量器３０が設けられている。ポンプ２４、循環パイプ２６、バルブ２８及び計量器３０は採取部を構成している。
【００２９】
計量器３０で計量された一定量のばいじんが供給される位置には撹拌容器３２が設けられており、計量器３０に残ったばいじんが廃却される位置には廃却容器３４が設けられている。
【００３０】
撹拌容器３２の上部には水貯槽３６が設けられており、その水貯槽３６からバルブ３８を経て一定量の水が撹拌容器３２に供給されるようになっている。撹拌容器３２にはスターラ４０が設けられている。撹拌容器３２の底部には撹拌容器３２内に残ったばいじん水溶液を排出するために、バルブ４２を備えた排出口が設けられている。
【００３１】
撹拌容器３２内のばいじん水溶液の上澄み液を分析試料とするために、その上澄み液を吸引するための吸引流路４４が設けられ、吸引流路４４にはロール式濾紙によるフィルタ６２が設けられており、撹拌容器３２から吸引された上澄み液中の固形物が除去されるようになっている。吸引流路４４には切換えバルブ５４を介してシリンジポンプ４８により試料を採取する試料ループ４６が接続されている。試料ループ４６とシリンジポンプ４８の間に設けられている切換えバルブ５２は、シリンジポンプ４８を試料ループ４６と洗浄水５０に切り換えて接続するための切換えバルブである。
【００３２】
試料ループ４６を吸引流路４４側と分析装置側に切り換える切換えバルブ５４の分析装置側には切換えバルブ６０を介して分析装置が接続されている。分析装置としては原子吸光光度計５６とＰ−アルカリ度又は酸度を測定する自動適定装置５８が切換えバルブ６０により選択されて試料ループ４６と接続されるようになっている。
【００３３】
原子吸光光度計５６と自動適定装置５８の検出信号は、それぞれが重金属安定剤供給部のポンプ２０とｐＨ調整剤供給部のポンプ１６を制御する信号として利用されるものであり、制御装置２に取り込まれる。制御装置２は図１に示された機能を実現するように構成されている。
【００３４】
次に、図１３の実施例の動作の一例について説明する。
循環パイプ２６の下端のバルブ２８が制御信号によって開かれ、循環パイプ２６を循環中のばいじんの一部が計量器３０のホッパーに供給される。計量器３０はホッパー中のばいじんを自動で５０ｇ計量し、撹拌容器３２に供給する。ホッパー及び計量器内に残ったばいじんは廃却容器３４へ排出される。
【００３５】
撹拌容器３２へばいじんが供給されるのと前後して水貯槽３６から５００ｇ（５００ｍｌ）の水が撹拌容器３２へ供給され、スターラ４０により３０分間撹拌される。撹拌容器３２内の不溶解物を沈殿させるために１０分間静置された後、バルブ５４，６０の切換え操作とシリンジポンプ４８の作動により、上澄み液の一部が試料ループ４６中に吸引された後、原子吸光光度計５６のサンプルバイヤル及び自動適定装置５８の測定容器に供給される。
【００３６】
原子吸光光度計５６では鉛を代表とする重金属の濃度が自動的に測定され、自動適定装置５８ではＰ−アルカリ度又は酸度が自動的に測定され、それぞれの測定値が制御装置２に送られる。
制御装置２ではこれらの２つの測定値から重金属安定剤及びｐＨ調整剤の適切な添加量が決定され、各々の薬剤を混練装置１２へ送るポンプ２０，１６の流量が調整される。この一連の自動分析及び薬剤量の制御は約１時間に１回の周期で行なわれる。
撹拌容器３２及び上澄み液吸引流路４４は次の測定が開始されるまでに水貯蔵３６から供給された水と洗浄水５０とによって洗浄される。
【００３７】
上記の実施例は混練装置１２で処理される前のばいじんを採取してＰ−アルカリ度、カルシウム溶出量もしくはｐＨ、又は重金属溶出量を測定する例であるが、処理前のばいじんに代えて、混練装置１２で処理された直後の処理ばいじん２２を用いて同様に薬剤添加量を制御することもできる。この場合、混練装置１２から排出される処理ばいじん２２の一定量を採取する採取装置７０が設けられ、採取装置７０により採取された一定量の処理ばいじんが撹拌容器３２に供給される。採取装置７０は処理前のばいじんを採取するポンプ２４、循環パイプ２６、バルブ２８及び計量器３０に代るものである。
【００３８】
図１３の実施例はその各部を種々に変形することができる。例えば、ばいじんサイロ１０からの処理前のばいじんの一定量を採取するのに、ポンプ２４に代えて、一定量を吸引して輸送する空気輸送方式を採用してもよい。撹拌容器３２でのスターラによる撹拌溶出を浸透溶出に置き換えることもできる。フィルタ６２のロール式濾紙による濾過を単一濾紙やフィルタを自動交換する形の濾過器に置き換えることも可能である。またフィルタ６２を逆洗浄する形の濾過器とすることもできる。上澄み液を採取するシリンジポンプ４８を他の形のポンプに置き換えることもできる。
【００３９】
実施例では約１時間の周期で薬剤添加量の制御を行なっているが、その周期の大部分の時間は撹拌容器３２での溶出処理である。そのため、撹拌容器３２を含む溶出のための機構を２組備え、交互に使用するようにすればほぼ１／２の周期で薬剤添加量の制御を行なうことができるようになる。
図１３の実施例ではＰ−アルカリ度もしくはカルシウム溶出量、酸度又はｐＨと、鉛などの重金属溶出量とをともに測定できるようにしているが、いずれか一方を測定するようにしてもよい。また、重金属溶出量のみを測定する場合は、撹拌容器３２での溶出処理のために添加する水として一定のｐＨ値に調製された水を使用してもよく、水を添加した後、さらに酸又はアルカリを添加してｐＨ値を一定に制御してもよい。また、水添加とともに重金属と水溶性化合物を生成する溶出剤を添加してもよい。
【００４０】
【発明の効果】
本発明では、混練装置で処理される前又は後のばいじん溶出液からのＰ−アルカリ度もしくはカルシウム溶出量、酸度又はｐＨの測定値に基づいてｐＨ調整剤添加量を制御したり、鉛などの重金属溶出量の測定値に基づいて重金属安定剤添加量を制御するようにしたので、１時間又はそれ以下の周期で自動分析から薬剤添加量制御までを行なうことができるようになる。その結果、ばいじんの安定処理に最適なｐＨ調整剤や重金属安定剤を添加することが可能となり、過度の薬剤消費を抑え、費用の節減や環境汚染を抑えることができる。
【図面の簡単な説明】
【図１】本発明での制御部を示すブロック図である。
【図２】処理前のばいじんの希釈溶出による時間とＰ−アルカリ度との関係を示す図である。
【図３】処理前のばいじんの希釈溶出による時間とカルシウム溶出量との関係を示す図である。
【図４】処理前のばいじんの希釈溶出による時間と鉛溶出量との関係を示す図である。
【図５】処理直後のばいじんの希釈溶出による時間とＰ−アルカリ度との関係を示す図である。
【図６】処理直後のばいじんの希釈溶出による時間と鉛溶出量との関係を示す図である。
【図７】処理前のばいじんを用いた制御動作を示すフローチャート図である。
【図８】希釈倍率が１０倍の場合のＰ−アルカリ度と硫酸バンド添加量との関係を示す図である。
【図９】希釈倍率が５００倍の場合のＰ−アルカリ度と硫酸バンド添加量との関係を示す図である。
【図１０】カルシウム溶出量と硫酸バンド添加量との関係を示す図である。
【図１１】鉛溶出量と液体キレート添加量との関係を示す図である。
【図１２】処理直後のばいじんを用いた制御動作を示すフローチャート図である。
【図１３】一実施例を示す概略構成図である。
【符号の説明】
２制御部
４薬液添加量データ記憶部
６薬液添加量算出部
８薬液添加制御部
１０ばいじんサイロ
１２混練装置
１４ｐＨ調整剤供給部
１８重金属安定剤供給部
２６循環パイプ
３０計量器
３２撹拌容器
４６試料パイプ
４８シリンジポンプ
５６原子吸光光度計
５８自動適定装置
７０採取装置[0001]
BACKGROUND OF THE INVENTION
In the incinerator for general waste and industrial waste, the present invention is not limited to dust collected by dust collection facilities such as electric dust collectors and bag filters among the waste discharged from the incinerator. In other words, it is related to an apparatus for performing intermediate treatment so that it can be disposed of as general waste or can be reused.
[0002]
[Prior art]
Soot and dust is designated as specially managed general waste under the revised Law on Waste Disposal and Cleaning (Waste Management Law), and general waste is not disposed of by any of the following four methods specified by the Minister of Health and Welfare. Cannot be disposed of as landfills (Ministry of Health and Welfare Notification No. 194).
(1) Melt solidification
(2) Cement solidification
(3) Drug treatment
(4) Stabilization with acids and other solvents
[0003]
When garbage is incinerated at a high temperature of a few thousand degrees, some heavy metals in the garbage are volatilized (evaporated) by the high temperature, but are cooled by collecting the dust and returned to a solid. Therefore, the dust contains a lot of heavy metals. The purpose of the intermediate treatment is to prevent heavy metals contained in the dust from eluting when the dust is disposed of in landfills.
Among the above intermediate treatment methods, the chemical treatment method is excellent in terms of equipment, maintenance and technology.
[0004]
Elution standards have been established for heavy metals such as lead, cadmium, hexavalent chromium, arsenic, mercury and selenium in intermediately treated soot and must be met for disposal.
Slaked lime is added to the exhaust gas line to treat the hydrogen chloride contained in the dust. When the soot is made into a 10% aqueous solution, the normal pH of the soot is about 9, but the soot aqueous solution after slaked lime injection is about 11-13.
It is known that the lead in the intermediately treated soot is hardly eluted when the pH is about 10, and is easily eluted regardless of whether the pH is higher or lower. In soot and dust generated in an incineration facility that performs exhaust gas treatment with an alkaline agent containing slaked lime (hereinafter referred to as alkali fly ash), the elution of lead is significant because the pH of the aqueous solution is high.
[0005]
On the other hand, dust and soot generated in incineration equipment that has not been treated with exhaust gas with an alkaline agent (hereinafter referred to as neutral fly ash) has a pH of about 6 to 10 so that lead and cadmium are detected above the elution standard. May be.
Therefore, in the chemical treatment method, liquid chelate is added as a heavy metal stabilizer that makes it difficult to elute heavy metals, and pH adjustment is performed with a pH adjuster.
[0006]
According to the method stipulated by the law, the amount of heavy metal eluted from the intermediately treated soot is obtained by eluting the treated product into water over 6 hours and subjecting the supernatant to treatment such as acid treatment and solvent extraction. Measured by atomic absorption spectrometry. Therefore, even if the analysis result requiring a long time is fed back to the dust processing device, the time delay may be too large and the properties of the dust may change, and stable intermediate processing must be performed. I can't. Therefore, a certain amount of heavy metal stabilizer such as liquid chelate is added so that the amount of elution of heavy metal does not protrude from the standard even if the properties of the dust change.
[0007]
In some cases, elution of heavy metals can be suppressed within a specified range simply by setting the pH after the intermediate treatment to around 10. Even in that case, since the dust and the treated product are solid, the pH value cannot be easily measured. Therefore, a certain amount of pH adjuster is currently injected.
[0008]
[Problems to be solved by the invention]
In the method of adding a certain amount of heavy metal stabilizer, if the amount of heavy metal in the dust is small, heavy metal stabilizer will be consumed more than necessary, resulting in waste of cost and reducing the amount of waste. The problem of making it larger than necessary arises.
[0009]
In the method of injecting a certain amount of pH adjusting agent, the amount of slaked lime injected varies depending on the amount of HCl in the exhaust gas, so the pH of the dust after the intermediate treatment constantly changes. Therefore, there is no guarantee that the dust after the intermediate treatment is always at a pH value at which heavy metals are difficult to elute.
[0010]
The first object of the present invention is to provide a treatment apparatus in which the amount of pH adjuster added can be controlled so that the pH of the treated material of the dusts becomes a value at which heavy metals are difficult to elute.
A second object of the present invention is to provide a processing apparatus that prevents useless addition of a heavy metal stabilizer and satisfies a prescribed heavy metal elution value.
The third object of the present invention is to control the addition amount of the pH adjuster so that the pH of the soot treated product becomes a value at which heavy metals are difficult to elute, prevent unnecessary addition of heavy metal stabilizers, and It is providing the processing apparatus which satisfy | fills a heavy metal elution value.
[0011]
[Means for Solving the Problems]
The dust processing apparatus of the present invention comprises a pH adjusting agent adding section for adding a pH adjusting agent to a kneading apparatus for processing by adding water or further cement to the dust of an incinerator and a heavy metal stabilizer adding section for adding a heavy metal stabilizer. At least one is provided. In order to control the addition amount of the pH adjuster and the addition amount of the heavy metal stabilizer, a sampling part for collecting a certain amount of the dust before or after the treatment by the kneading apparatus, and a certain amount of water are added to the collected dust. The elution part that stirs and elutes the components contained in the dust in a few minutes to several tens of minutes, and the P-alkalinity or calcium elution amount, acidity or Measurement comprising at least one of an alkalinity / acidity measurement unit for measuring pH and a heavy metal measurement unit for measuring the amount of heavy metal elution containing at least lead in the eluate from the elution unit for controlling the amount of heavy metal stabilizer added Part and a control part.
[0012]
In the case where a heavy metal measuring unit is provided, in order to easily elute lead and cadmium, water adjusted to a certain pH value can be used as water added to the dust at the elution unit. Further, after adding water, an acid or alkali may be added to control the pH value to be constant. Sulfuric acid, nitric acid, hydrochloric acid, acetic acid and the like can be used to make the pH value of the water to be added or the pH value at the elution part acidic. In order to bring the pH value of the water to be added or the pH value at the elution part to the alkaline side, caustic soda or calcium hydroxide can be used.
[0013]
When a heavy metal measuring unit is provided, an eluent that generates a heavy metal and a water-soluble compound may be added in addition to water in order to easily elute lead and cadmium. As such an eluent, citric acid or oxalic acid can be used, and carbon dioxide gas may be blown.
The term “kneading device” is used to include all of a humidity control device for adding water or even cement to a soot and mixing it, a device intended for mixing, and a molding machine.
[0014]
The control unit performs the function shown in FIG. The control unit 2 includes a chemical solution addition amount calculation unit 6 and a chemical solution addition control unit 8, and further includes a chemical solution addition amount data storage unit 4 when measuring an eluate of dust before processing.
When measuring and controlling the eluate of the dust before the treatment by the kneading apparatus, the chemical solution addition amount data storage unit 4 has the P-alkaliness or calcium elution amount, acidity or Data of pH adjuster addition amount relative to pH is stored, and the chemical solution addition amount calculation unit 6 follows the data in the chemical solution addition amount data storage unit 4 to add pH adjuster corresponding to the measured value in the alkalinity / acidity measurement unit Calculate the amount. The chemical solution addition control unit 8 controls the operation of the pH adjuster addition unit so that the pH adjuster addition amount from the pH adjuster addition unit becomes the calculated amount of the pH adjuster addition amount in the chemical solution addition amount calculation unit 6. In order to control the heavy metal stabilizer addition amount, the chemical solution addition amount data storage unit 4 stores data of the heavy metal stabilizer addition amount with respect to the heavy metal elution amount, and the chemical solution addition amount calculation unit 6 stores the chemical solution addition amount data storage unit. According to the data of No. 4, the heavy metal stabilizer addition amount corresponding to the measured value in the heavy metal measuring unit is calculated. The chemical solution addition control unit 8 controls the operation of the heavy metal stabilizer addition unit so that the heavy metal stabilizer addition amount from the heavy metal stabilizer addition unit becomes the amount calculated by the chemical solution addition amount calculation unit. In order to control both the added amount of the pH adjuster and the added amount of the heavy metal stabilizer, the respective parts 4, 6 and 8 serve both functions for adding both chemical solutions.
[0015]
When measuring and controlling the dust eluate after treatment by the kneading device, in order to control the amount of pH adjuster added, If the dust is alkaline fly ash, After starting with an appropriate chemical solution injection amount, the chemical solution addition amount calculation unit 6 determines the addition amount for the second and subsequent times, Alkalinity measurement unit The measured value at If it is above the specified value, increase the amount of the next pH adjuster addition from the previous time, and if it is less than the specified value, it is compared with the previous P-alkalinity or calcium elution amount and increased from the previous measured value. If it is not increased, the amount of the pH adjuster added next time will be the same as the previous time. The amount of pH adjuster added is calculated as follows. The chemical solution addition control unit 8 controls the operation of the pH adjuster addition unit so that the pH adjuster addition amount from the pH adjuster addition unit becomes the amount calculated by the chemical solution addition amount calculation unit 6. In order to control the addition amount of the heavy metal stabilizer, after starting with an appropriate injection amount of the chemical solution, the chemical solution addition amount calculation unit 6 sets the second and subsequent addition amounts so that the measured value in the heavy metal measurement unit is a predetermined value or more. If there is, increase it from the previous heavy metal stabilizer addition amount, and if it is less than the predetermined value and the same or decrease as the previous measurement value, then decrease it from the previous heavy metal stabilizer addition amount, and lower than the predetermined value, the previous measurement value If it has increased, the amount of heavy metal stabilizer added is calculated so as to be the same amount as the previous amount of heavy metal stabilizer added. The chemical solution addition control unit 8 controls the operation of the heavy metal stabilizer addition unit so that the heavy metal stabilizer addition amount from the heavy metal stabilizer addition unit becomes the amount calculated by the chemical solution addition amount calculation unit 6. Also in this case, in order to control both the addition amount of the pH adjuster and the addition amount of the heavy metal stabilizer, the chemical solution addition amount calculation unit 6 and the chemical solution addition control unit 8 fulfill both functions for adding both chemical solutions.
[0016]
A part for measuring the amount of P-alkali or calcium elution, acidity or pH to control the amount of pH adjuster added, and a part for measuring the concentration of heavy metal containing at least lead to control the amount of added heavy metal stabilizer, Only one of them may be provided, or both of them may be provided, and both the pH adjusting agent and the heavy metal stabilizer may be added.
The alkalinity / acidity measurement unit is an alkali measurement unit that measures P-alkalinity or calcium elution when the dust to be treated is alkaline fly ash. The P-alkalinity is specified in the water test of JIS standard K0101, and an automatic titration apparatus is commercially available for automatically measuring the P-alkalinity. Such an automatic titration apparatus can be used for P-alkalinity measurement in the present invention.
[0017]
The alkalinity / acidity measurement unit is an acidity measurement unit that measures acidity when the dust to be treated is neutral fly ash. The acidity measurement can also be carried out using an automatic titration apparatus similar to the P-alkalinity measurement and using an alkaline solution such as a caustic soda solution as a titration reagent.
The calcium elution amount can be measured with an atomic absorption photometer.
The pH can be measured with a pH meter, and the addition amount of the pH adjusting agent may be controlled according to the pH value.
[0018]
Heavy metals to be measured include lead, cadmium, hexavalent chromium, arsenic, mercury and selenium. Lead is the most abundant heavy metal, but in addition to lead, some regions contain a lot of mercury and cadmium. Depending on the region, the type of heavy metal to be measured may be only lead, or lead, mercury, cadmium and other heavy metals may be included. The concentration of these heavy metals can be measured by using a hollow cathode lamp using a metal to be measured as a light source with an atomic absorption photometer. In order to measure the concentration of these heavy metals, an ICP (inductively coupled plasma) apparatus can be used in place of the atomic absorption photometer.
As pH adjusters, sulfuric acid bands, polyiron, ferric chloride and other aqueous solutions are used for alkaline fly ash, and alkaline solutions such as caustic soda, calcium hydroxide and magnesium hydroxide are used for neutral fly ash. Can be used.
As the heavy metal stabilizer, a liquid chelate, an inorganic processing agent, or the like can be used.
[0019]
In order to investigate whether or not soot can be eluted in a short time, the results of diluting and eluting soot before treatment by the kneading apparatus with water are shown in FIGS. It measured about the aqueous solution diluted 10 times, 100 times, and 1000 times, respectively, FIG. 2 measured P-alkalinity, FIG. 3 measured calcium elution amount, FIG. 4 measured lead elution amount, respectively. P-alkalinity, calcium elution amount, and lead elution amount differ depending on the incineration equipment, but both are in an equilibrium state with elution for several minutes to several tens of minutes.
[0020]
FIG. 5 and FIG. 6 show the results of measuring the dust in the same manner immediately after adding the liquid chelate and treating it with the kneading apparatus. FIG. 5 shows the P-alkalinity, and FIG. 6 shows the lead elution amount. In this case as well, both the P-alkalinity and the lead elution amount are in an equilibrium state with elution for several minutes to several tens of minutes, and the measurement result of the calcium elution amount is not shown, but the same result was obtained. Yes.
If the dilution factor exceeds 1000 times and becomes too large, there is a possibility that the apparatus becomes excessive, and therefore a dilution of about 10 to 1000 times is appropriate.
[0021]
When the soot is alkaline fly ash, the operation of controlling the addition amount of the pH adjusting agent based on the P-alkalinity measured by the automatic titration device from the eluate of the dust before being treated will be described with reference to FIGS. To do.
The chemical addition amount data storage unit 4 of the control device 2 stores data indicating the addition amount of a pH adjusting agent (for example, sulfuric acid band) with respect to the P-alkalinity as shown in FIGS. FIG. 8 shows the case of 10-fold dilution, and FIG. 9 shows the case of 500-fold dilution. When the P-alkalinity is measured by the automatic leveling device, the chemical addition amount calculation unit 6 calculates the addition amount of the pH adjuster, and the chemical addition control unit 8 controls the supply flow rate from the pH adjustment agent addition unit. Then add the pH adjuster to the kneader.
[0022]
The calcium elution amount may be measured by an atomic absorption photometer instead of P-alkalinity. In that case, the chemical solution addition amount data storage unit 4 stores data indicating the addition amount of the pH adjuster (for example, sulfate band) with respect to the calcium elution amount as shown in FIG. 10, and the pH adjuster is based on this data. The amount of addition of is adjusted.
When the dust is neutral fly ash, acidity is measured instead of P-alkalinity. In that case, the chemical solution addition amount data storage unit 4 stores data indicating the addition amount of the alkaline solution as the pH adjuster with respect to the acidity measurement value, instead of the data of FIGS. In this case, the operation is the same. When the acidity is measured by the automatic leveling device, the chemical solution addition amount calculation unit 6 calculates the addition amount of the pH adjuster, and the chemical solution addition control unit 8 starts from the pH adjuster addition unit. The pH adjusting agent is added to the kneading apparatus while controlling the flow rate of
[0023]
FIG. 7 shows the operation of controlling the amount of liquid chelate added as a heavy metal stabilizer based on the signal of the amount of heavy metal elution (as an example, the amount of lead elution) measured from an eluate of dust before being processed by an atomic absorption photometer. This will be described with reference to FIG. Data indicating the amount of lead elution and the amount of liquid chelate added as shown in FIG. 11 is stored in the drug addition amount data storage unit 4 of the control unit 2, and when the amount of lead elution is measured, Based on this, the chemical addition amount calculation unit 6 calculates the liquid chelate addition amount, and the chemical addition control unit 8 adjusts the supply flow rate from the heavy metal stabilizer addition unit to add a predetermined amount of liquid chelate to the kneading apparatus.
[0024]
FIG. 12 shows the operation in the case where control is performed using the eluate of dust after being processed by the kneading apparatus. In this case, control is performed so that the P-alkalinity, the calcium elution degree or pH, or the elution amount of lead and other heavy metals in the dust after the treatment becomes a predetermined value.
[0025]
When the dust is alkaline fly ash, Reduce P-alkalinity The case of controlling the amount of the pH adjuster added will be described. First, an appropriately set amount of the pH adjuster is added to the kneading apparatus. Then, the P-alkalinity is measured from the eluate of the dust immediately after the treatment in the kneading apparatus by an automatic titration apparatus, or the calcium elution amount is measured by an atomic absorption photometer. For certain values where heavy metals such as lead are difficult to elute, The pH value corresponding to the measured value is That If it is greater than or equal to the specified value Because the amount of the previous addition was not enough, Increase the amount of the next pH adjuster addition from the previous time. If it is less than the predetermined value, compare with the previous P-alkalinity or calcium elution amount, and if it is higher than the previous measured value Since the previous addition amount is close to the appropriate amount If the amount of the next pH adjuster addition is the same as the previous one and it has not increased To get closer to the specified value Reduce weight than last time. When the measurement of P-alkalinity or calcium elution amount is the first, even if the P-alkalinity or calcium elution amount is less than a predetermined value, it cannot be compared with the previous P-alkalinity or calcium elution amount. Therefore, the addition amount of the pH adjuster is the same as the previous time (first one).
[0026]
When the dust is neutral fly ash, the acidity is measured instead of the P-alkalinity and controlled in the same manner as in FIG.
When the elution amount of lead and other heavy metals is measured by an atomic absorption photometer, the control of the addition amount of the heavy metal stabilizer is as shown in FIG.
As described above, if the control is performed using the eluate of the dust after being processed by the kneading apparatus, it is possible to prevent useless addition of the pH adjusting agent or the heavy metal safener.
[0027]
【Example】
FIG. 13 shows an embodiment.
Reference numeral 10 denotes a dust silo, in which dust collected by an electric dust collector of a waste incinerator is accommodated. The dust contained in the dust silo 10 is taken out from the bottom to the kneading device 12. Water is added to the kneading device 12 in order to solidify the dust. Since slaked lime has already been added to the soot, it is solidified only by adding water, but cement may also be added. In the kneading apparatus 12, either or both of a pH adjuster from the pH adjuster supply unit 14 and a heavy metal stabilizer from the heavy metal stabilizer supply unit 18 are added. The addition amount of the pH adjusting agent and the addition amount of the heavy metal stabilizer are controlled by the respective supply pumps 16 and 20 controlled by the control device 2. The treated dust 22 solidified by the kneading device 12 is disposed as landfill or the like as general waste.
[0028]
In order to collect a certain amount of the dust before processing from the dust silo 10, the dust silo 10 is provided with a pump 24 such as a screw pump, and the dust extracted by the pump 24 is recirculated by the circulation pipe 26. A circulation flow path is provided to return to. A valve 28 is provided at the lower end of the circulation pipe 26 to take out the dust moving along the circulation pipe. Below the valve 28, a hopper for receiving the dust supplied from the valve 28 is provided, and a measuring device 30 for measuring the dust is provided. The pump 24, the circulation pipe 26, the valve 28, and the meter 30 constitute a sampling part.
[0029]
A stirring container 32 is provided at a position where a certain amount of dust measured by the measuring instrument 30 is supplied, and a disposal container 34 is provided at a position where the dust remaining in the measuring instrument 30 is discarded. Yes.
[0030]
A water storage tank 36 is provided above the stirring container 32, and a certain amount of water is supplied from the water storage tank 36 to the stirring container 32 through a valve 38. A stirrer 40 is provided in the stirring vessel 32. A discharge port provided with a valve 42 is provided at the bottom of the stirring vessel 32 in order to discharge the aqueous dust solution remaining in the stirring vessel 32.
[0031]
In order to use the supernatant liquid of the soot and dust solution in the stirring vessel 32 as an analysis sample, a suction flow path 44 for sucking the supernatant liquid is provided, and the suction flow path 44 is provided with a filter 62 made of roll filter paper. The solid matter in the supernatant liquid sucked from the stirring vessel 32 is removed. A sample loop 46 for collecting a sample by a syringe pump 48 is connected to the suction channel 44 via a switching valve 54. A switching valve 52 provided between the sample loop 46 and the syringe pump 48 is a switching valve for switching and connecting the syringe pump 48 to the sample loop 46 and the washing water 50.
[0032]
An analyzer is connected via a switching valve 60 to the analyzer side of the switching valve 54 for switching the sample loop 46 between the suction channel 44 side and the analyzer side. As an analysis device, an atomic absorption photometer 56 and an automatic determination device 58 for measuring P-alkalinity or acidity are selected by a switching valve 60 and connected to the sample loop 46.
[0033]
The detection signals of the atomic absorption photometer 56 and the automatic leveling device 58 are used as signals for controlling the pump 20 of the heavy metal stabilizer supply unit and the pump 16 of the pH adjuster supply unit, respectively. Is taken in. The control device 2 is configured to realize the functions shown in FIG.
[0034]
Next, an example of the operation of the embodiment of FIG. 13 will be described.
A valve 28 at the lower end of the circulation pipe 26 is opened by a control signal, and a part of the dust circulating in the circulation pipe 26 is supplied to the hopper of the meter 30. The meter 30 automatically weighs 50 g of the dust in the hopper and supplies it to the stirring container 32. The dust remaining in the hopper and the measuring instrument is discharged to the disposal container 34.
[0035]
About 500 g (500 ml) of water is supplied from the water storage tank 36 to the stirring container 32 before and after the dust is supplied to the stirring container 32, and is stirred by the stirrer 40 for 30 minutes. After allowing to stand for 10 minutes to precipitate the insoluble matter in the stirring vessel 32, a part of the supernatant was sucked into the sample loop 46 by the switching operation of the valves 54 and 60 and the operation of the syringe pump 48. Thereafter, the sample vial of the atomic absorption photometer 56 and the measurement container of the automatic leveling device 58 are supplied.
[0036]
The atomic absorption photometer 56 automatically measures the concentration of heavy metals such as lead, and the automatic leveling device 58 automatically measures P-alkalinity or acidity, and sends each measured value to the controller 2. It is done.
In the control device 2, appropriate addition amounts of the heavy metal stabilizer and the pH adjusting agent are determined from these two measured values, and the flow rates of the pumps 20 and 16 that send the respective chemicals to the kneading device 12 are adjusted. This series of automatic analysis and drug amount control is performed at a cycle of about once per hour.
The stirring vessel 32 and the supernatant liquid suction channel 44 are washed with the water supplied from the water storage 36 and the washing water 50 until the next measurement is started.
[0037]
The above example is an example of collecting the dust before being processed by the kneading apparatus 12 and measuring the P-alkalinity, calcium elution amount or pH, or heavy metal elution amount, but instead of the dust before the treatment, It is also possible to control the amount of drug added in the same manner using the processing dust 22 immediately after being processed by the kneading apparatus 12. In this case, a collection device 70 for collecting a certain amount of the processing dust 22 discharged from the kneading device 12 is provided, and a certain amount of the processing dust collected by the sampling device 70 is supplied to the stirring container 32. The sampling device 70 is a substitute for the pump 24, the circulation pipe 26, the valve 28, and the meter 30 for collecting the dust before processing.
[0038]
The embodiment shown in FIG. 13 can be variously modified. For example, in order to collect a certain amount of dust before processing from the dust silo 10, an air transportation method in which a certain amount is sucked and transported instead of the pump 24 may be employed. The stirring elution by the stirrer in the stirring container 32 can be replaced with the osmotic elution. It is also possible to replace the filtration of the filter 62 by the roll type filter paper with a single filter paper or a filter that automatically replaces the filter. Further, the filter 62 may be a backwasher type filter. The syringe pump 48 for collecting the supernatant can be replaced with another type of pump.
[0039]
In the embodiment, the drug addition amount is controlled in a cycle of about 1 hour, but most of the cycle is the elution process in the stirring vessel 32. For this reason, if two sets of elution mechanisms including the stirring vessel 32 are provided and used alternately, the amount of drug added can be controlled with a period of approximately ½.
In the embodiment of FIG. 13, the P-alkalinity or calcium elution amount, acidity or pH and the elution amount of heavy metals such as lead can be measured together, but either one may be measured. In addition, when measuring only the elution amount of heavy metal, water adjusted to a certain pH value may be used as the water to be added for the elution treatment in the stirring vessel 32. Alternatively, the pH value may be controlled to be constant by adding an alkali. Moreover, you may add the eluent which produces | generates a heavy metal and a water-soluble compound with water addition.
[0040]
【The invention's effect】
In the present invention, the amount of P-alkaline or calcium elution from the dust eluate before or after being processed in the kneading apparatus is controlled based on the measured value of the pH or acidity or pH, Since the heavy metal stabilizer addition amount is controlled based on the measurement value of the heavy metal elution amount, automatic analysis to drug addition amount control can be performed in a cycle of one hour or less. As a result, it is possible to add a pH adjusting agent and a heavy metal stabilizer that are optimal for the stabilization of soot and dust, thereby suppressing excessive drug consumption, reducing costs, and preventing environmental pollution.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a control unit in the present invention.
FIG. 2 is a diagram showing the relationship between the time required for diluting and eluting soot before treatment and the P-alkalinity.
FIG. 3 is a diagram showing the relationship between the time taken for dilution elution of dust before treatment and the amount of calcium elution.
FIG. 4 is a diagram showing the relationship between the time taken for dilution elution of dust before processing and the amount of lead elution.
FIG. 5 is a graph showing the relationship between the time required for diluting and eluting soot immediately after treatment and the P-alkalinity.
FIG. 6 is a diagram showing the relationship between the time taken for dilute elution of dust immediately after treatment and the amount of lead elution.
FIG. 7 is a flowchart showing a control operation using dust before processing.
FIG. 8 is a diagram showing the relationship between the P-alkalinity and the amount of sulfuric acid band added when the dilution factor is 10 times.
FIG. 9 is a graph showing the relationship between the P-alkalinity and the amount of sulfuric acid band added when the dilution factor is 500 times.
FIG. 10 is a graph showing the relationship between the calcium elution amount and the sulfate band addition amount.
FIG. 11 is a diagram showing the relationship between the amount of lead elution and the amount of liquid chelate added.
FIG. 12 is a flowchart showing a control operation using dust immediately after processing.
FIG. 13 is a schematic configuration diagram showing one embodiment.
[Explanation of symbols]
2 Control unit
4 Chemical solution addition data storage
6 Chemical solution addition amount calculation part
8 Chemical addition control unit
10 Dust silo
12 Kneading equipment
14 pH adjuster supply section
18 Heavy metal stabilizer supply section
26 Circulation pipe
30 Weighing scale
32 Stirring container
46 Sample pipe
48 syringe pump
56 Atomic absorption photometer
58 Automatic leveling equipment
70 Collection device

Claims

A kneader for adding water or even cement to the dust in the incinerator,
A pH adjuster addition unit for further adding a pH adjuster to the kneading device;
A collecting part for collecting a certain amount of dust before treatment by the kneading device;
An elution part that adds a certain amount of water to the collected dust and stirs, and elutes the components contained in the dust in several minutes to several tens of minutes,
An alkalinity / acidity measurement unit for measuring the P-alkaline or calcium elution amount, acidity or pH of the eluate from the elution part;
P-alkalinity or calcium elution amount, acidity or pH adjuster addition amount data storage unit storing data of pH, and according to the data of the chemical solution addition amount data storage unit, the alkalinity / acidity measurement unit The chemical solution addition amount calculation unit that calculates the pH adjustment agent addition amount corresponding to the measured value in the above, and the pH adjustment agent addition amount from the pH adjustment agent addition unit is the calculation amount in the chemical solution addition amount calculation unit and a control unit including a chemical solution addition control unit for controlling the operation of the pH adjuster addition unit.

A kneader for adding water or even cement to the dust in the incinerator,
A heavy metal stabilizer addition part for further adding a heavy metal stabilizer to the kneading device,
A collecting part for collecting a certain amount of dust before treatment by the kneading device;
An elution part that adds a certain amount of water to the collected dust and stirs, and elutes the components contained in the dust in several minutes to several tens of minutes,
A heavy metal measuring unit for measuring a heavy metal elution amount containing at least lead in the eluate from the elution unit;
The amount of heavy metal stabilizer added corresponding to the measured value in the heavy metal measurement unit according to the data in the chemical solution addition amount data storage unit storing the data of the amount of heavy metal stabilizer added to the amount of heavy metal elution And a chemical solution addition unit for controlling the operation of the heavy metal stabilizer addition unit so that the heavy metal stabilizer addition amount from the heavy metal stabilizer addition unit becomes a calculation amount in the chemical solution addition amount calculation unit And a control unit including a control unit.

A kneader for adding water or even cement to the dust in the incinerator,
A pH adjuster addition unit for further adding a pH adjuster to the kneading device;
A heavy metal stabilizer addition part for further adding a heavy metal stabilizer to the kneading device,
A collecting part for collecting a certain amount of dust before treatment by the kneading device;
An elution part that adds a certain amount of water to the collected dust and stirs, and elutes the components contained in the dust in several minutes to several tens of minutes,
An alkalinity / acidity measurement unit for measuring the P-alkaline or calcium elution amount, acidity or pH of the eluate from the elution part;
A heavy metal measuring unit for measuring a heavy metal elution amount containing at least lead in the eluate from the elution unit;
Chemical solution addition data storage unit storing data of pH adjuster addition amount with respect to P-alkalinity or calcium elution amount, acidity or pH, and heavy metal stabilizer addition amount data with respect to heavy metal elution amount, this chemical solution addition amount data storage In accordance with the data of the part, the chemical solution addition amount calculating unit for calculating the pH adjusting agent addition amount corresponding to the measurement value in the alkalinity / acidity measurement unit and the heavy metal stabilizer addition amount corresponding to the measurement value in the heavy metal measurement unit, And controlling the operation of the pH adjuster addition unit so that the pH adjuster addition amount from the pH adjuster addition unit becomes the calculated amount of the pH adjuster addition amount in the chemical addition amount calculation unit, and the heavy metal stabilizer A chemical liquid addition control unit that controls the operation of the heavy metal stabilizer addition unit so that the heavy metal stabilizer addition amount from the addition unit becomes the calculated amount of the heavy metal stabilizer addition amount in the chemical solution addition amount calculation unit; Dust processing apparatus characterized by comprising: a control unit.

A kneading device for adding water or further cement to the dust that is the alkali fly ash of the incinerator;
A pH adjuster addition unit for further adding a pH adjuster to the kneading device;
A collection unit for collecting a certain amount of dust after processing by the kneading apparatus;
An elution part that adds a certain amount of water to the collected dust and stirs, and elutes the components contained in the dust in several minutes to several tens of minutes,
An alkalinity measuring unit for measuring the P-alkalinity or calcium elution amount of the eluate from the elution part ;
After starting from an appropriate pH adjuster addition amount, if the measured value in the alkalinity measurement unit is greater than or equal to a predetermined value, increase the next pH adjuster addition amount from the previous time, if less than the predetermined value Compared to the previous P-alkalinity or calcium elution amount, if it is higher than the previous measured value, the next pH adjuster addition amount will be the same as the previous one, and if not increased, the chemical solution addition amount will be reduced from the previous time A control unit including a calculation unit, and a chemical solution addition control unit that controls the operation of the pH adjustment agent addition unit so that the pH adjustment agent addition amount from the pH adjustment agent addition unit becomes the calculation amount in the chemical solution addition amount calculation unit And a dust processing apparatus.

A kneading device for adding water or even cement to the dust in an incinerator;
A heavy metal stabilizer addition part for further adding a heavy metal stabilizer to the kneading device,
A collection unit for collecting a certain amount of dust after processing by the kneading device;
An elution part that adds a certain amount of water to the collected dust and stirs, and elutes the components contained in the dust in several minutes to several tens of minutes,
A heavy metal measuring unit for measuring a heavy metal elution amount containing at least lead in the eluate from the elution unit;
After starting from an appropriate heavy metal stabilizer addition amount, if the measured value at the heavy metal measuring section is equal to or greater than the predetermined value, the amount is increased from the previous heavy metal stabilizer addition amount, and less than the predetermined value is the same as the previous measured value. Or if it is decreased, it will be reduced from the previous heavy metal stabilizer addition amount, and if it is less than the predetermined value and increased from the previous measurement value, it will be the same amount as the previous heavy metal stabilizer addition amount. And a control unit including a chemical liquid addition control unit that controls the operation of the heavy metal stabilizer addition unit so that the heavy metal stabilizer addition amount from the heavy metal stabilizer addition unit becomes a calculation amount in the chemical liquid addition amount calculation unit, A dust processing apparatus characterized by comprising:

A kneading device for adding water or even cement to the dust in an incinerator;
A pH adjuster addition unit for further adding a pH adjuster to the kneading device;
A heavy metal stabilizer addition part for further adding a heavy metal stabilizer to the kneading device,
A collection unit for collecting a certain amount of dust after processing by the kneading apparatus;
An elution part that adds a certain amount of water to the collected dust and stirs, and elutes the components contained in the dust in several minutes to several tens of minutes,
An alkalinity measuring unit for measuring the P-alkalinity or calcium elution amount of the eluate from the elution part ;
A heavy metal measuring unit for measuring a heavy metal elution amount containing at least lead in the eluate from the elution unit;
When controlling the amount of pH adjuster added to the soot of alkaline fly ash, start from an appropriate amount of pH adjuster added, and if the measured value in the alkalinity measuring unit is greater than or equal to a predetermined value, the next pH adjustment If the amount added is higher than the previous value and is less than the predetermined value, it is compared with the previous P-alkalinity or calcium elution amount. If it is not increased, the amount is reduced from the previous time, and when controlling the amount of heavy metal stabilizer added, after starting from an appropriate amount of added heavy metal stabilizer, the measured value in the heavy metal measuring unit is a predetermined value. If it is above, it will be increased from the previous heavy metal stabilizer addition amount, and if it is less than or equal to the previous measurement value below the predetermined value, it will be reduced from the previous heavy metal stabilizer addition amount and less than the predetermined value will be the previous value. If it is higher than the measured value, The chemical solution addition amount calculation unit having the same amount as the heavy metal stabilizer addition amount, and the pH adjustment agent addition amount from the pH adjustment agent addition unit become the calculation amount of the pH adjustment agent addition amount in the chemical solution addition amount calculation unit The heavy metal stabilizer is controlled such that the amount of heavy metal stabilizer added from the heavy metal stabilizer addition unit becomes the calculated amount of the heavy metal stabilizer addition amount in the chemical addition amount calculation unit. And a control unit including a chemical addition control unit for controlling the operation of the addition unit.

The dust treatment apparatus according to claim 2 or 5, wherein the water added to the dust in the elution part is water adjusted to a neutral or constant pH value.

The dust treating apparatus according to claim 2 or 5, wherein an acid or an alkali is further added to the elution part to control the pH value to be constant.

The dust treating apparatus according to claim 2 or 5, wherein an eluting agent that generates a heavy metal and a water-soluble compound is further added to the eluting unit.