JP3611022B2

JP3611022B2 - Measurement method for loss of ignition of sludge

Info

Publication number: JP3611022B2
Application number: JP36355399A
Authority: JP
Inventors: 和男長▲濱▼; 寛通安東; 正矢野; 誠黒田
Original assignee: Kubota Corp
Current assignee: Kubota Corp
Priority date: 1999-12-22
Filing date: 1999-12-22
Publication date: 2005-01-19
Anticipated expiration: 2019-12-22
Also published as: JP2001174384A

Description

【０００１】
【発明の属する技術分野】
本発明は、汚泥の強熱減量計測方法に関し、汚泥溶融炉等において用いる汚泥分析計に係る技術である。
【０００２】
【従来の技術】
近年、下水処理施設では、汚泥の効率的処分を目的として広域汚泥処理を採用する傾向にある。しかし、搬入される汚泥性状は時間変動を生じ易く、焼却、溶融処理プラントの安定運転に影響を及ぼしている。このような、処理プラントにおいて汚泥の含水率、強熱減量を事前に計測することは、プラントの安定運転を行なうために重要である。
【０００３】
この測定は、日本下水道協会が定める試験方法に基づいて行なっている。水分は、試料汚泥を１０５〜１１０℃で２時間乾燥し、経過後の全蒸発残留物の重量を測定し、乾燥前の試料汚泥の重量との差を算出する。強熱減量は、含水率計測後の全蒸発残留物を６００±２５℃で１時間強熱灰化し、経過後の強熱残留物の重量を測定し、全蒸発残留物の重量との差を算出する。
【０００４】
従来の汚泥含水率や強熱減量の計測装置においては、溶融炉等へ汚泥を供給する送泥本管から汚泥を計測装置へ引き込み、引き込んだ汚泥から試料汚泥（５ｇ）を予め重量計測した試料皿に採取し、始めに加熱計量室内において試料汚泥の重量を計測する。次に、乾燥工程における加熱によって試料汚泥の水分を蒸発させ、その後に全蒸発残留物の重量を計測し、この計測値と乾燥前の試料汚泥の重量との差を算出して水分量を求め、水分量を乾燥前の試料汚泥の重量で除算して含水率を算出する。続いて、強熱灰化工程における加熱によって燃焼させ、その後に強熱残留物の重量を計測し、この計測値と全蒸発残留物の重量との差を強熱減量として算出する。
【０００５】
この一連の計測処理工程が終了した時点で、計測操作サイクルの最初に戻り、前回に引き込んだ汚泥を廃棄し、新たに送泥本管から汚泥を計測装置へ引き込み、計測操作を繰り返す。そして、１回の計測操作が終了する毎に、計測結果を外部へ伝送出力し、計測出力値を更新する。
【０００６】
【発明が解決しようとする課題】
上記した従来の構成において、５ｇの試料汚泥において含水率が８０％とすると、乾燥後の全蒸発残留物の重量は１ｇとなる。その後の強熱灰化工程での強熱減量を１％の精度で計測するためには、強熱残留物の重量の計測において１０ｍｇ以上の測定誤差は許されない。
【０００７】
ところで、採取した試料汚泥の中には、希に石の欠片などの固形異物が混じっており、この場合には正確な計測結果を得ることができない。しかし、計測結果それ自体からは、その計測値が汚泥性状の変化を反映した正常な値か、固形異物に起因する異常な値であるかは判断することができない。このため、計測結果をそのまま出力すると、次回の計測結果を得るまでの間は誤った値に基づいて溶融炉等の運転を行なうことになる。
【０００８】
本発明は上記した課題を解決するものであり、計測結果を短時間の内に評価する強熱減量計測方法を提供することを目的とする。
【０００９】
【課題解決するための手段】
上記課題を解決するために、本発明の強熱減量計測方法は、毎回の計測操作の始めに汚泥供給源から適当量の計測対象汚泥を取り込み、計測対象汚泥から所定量の試料汚泥を採取し、乾燥前の試料汚泥の重量と、乾燥工程後の全蒸発残留物の重量と、強熱灰化工程後の強熱残留物の重量とを計測し、試料汚泥の重量と全蒸発残留物の重量との差分である水分量を試料汚泥の重量で除算して試料汚泥の含水率を求め、全蒸発残留物の重量と強熱残留物の重量との差分を全蒸発残留物の重量で除算して強熱減量を算出する強熱減量計測方法において、算出した強熱減量を本計測値として記録し、前回計測値に対する本計測値の変動量を一次評価値として求め、一次評価値が予め設定する評価基準値未満である場合には、本計測値を正常計測値と評価し、一次評価値が評価基準量以上である場合および初回の計測操作時には、同じ計測対象汚泥から新たに所定量の評価用試料汚泥を採取して評価計測を行ない、評価計測において評価用試料汚泥の重量と、強熱灰化工程後の強熱残留物の重量を計測し、評価用試料汚泥の重量と本計測値の計測時に求めた含水率とに基づいて評価用試料汚泥の全蒸発残留物の重量を算出し、評価用試料汚泥における全蒸発残留物の重量と強熱残留物の重量との差分である強熱減量を再評価用計測値として算出し、再評価用計測値と本計測値との差分を二次評価値として求め、二次評価値が予め設定する再評価基準値未満である場合には、本計測値を正常計測値と評価し、二次評価値が再評価基準値以上である場合には、本計測値を異常計測値と判断し、汚泥供給源から新たに計測対象汚泥を取り込んで改めて計測操作を行なうものである。
【００１０】
上記した構成により、毎回の計測操作時に汚泥供給源から計測対象汚泥を取り込み、試料汚泥を採取して強熱減量を計測することにより、汚泥供給源における汚泥性状の経時的変化を計測する。
各計測操作での計測結果を一次評価し、強熱減量の計測値が前回の計測値から大きく変化した場合、例えば前回の計測値に対して今回の計測値が１％以上の変動量を有する場合に、もしくは前回の計測値が得られていない初回の計測操作の場合には、計測した強熱減量の計測値の正当性を二次評価するために、今回計測した計測値を本計測値として保留し、評価用計測値を求める。
【００１１】
この評価用計測値の計測においては、溶融炉等へ汚泥を供給する送泥本管（汚泥供給源）から新たな計測対象汚泥の取り込みを行なわずに、計測装置の配管内に残留している同じ計測対象汚泥から評価用試料汚泥を再度採取する。このことにより、評価用試料汚泥が本計測の試料汚泥と同じ汚泥性状となるので、評価用試料汚泥の強熱減量と本計測の強熱減量とを比較することは、本計測の計測精度を検証することになる。
【００１２】
評価計測操作では、評価用試料汚泥の重量測定後に、乾燥工程を行なわずに直ちに、強熱灰化工程において強熱灰化して強熱残留物の重量を計測する。そして、評価用試料汚泥の含水率は先に本計測で得た値と同じであるとして、評価用試料汚泥の重量に本計測の含水率を乗算して全蒸発物重量を求め、評価用試料汚泥の重量から全蒸発物重量を減算して評価用試料汚泥における全蒸発残留物の重量を算出し、評価用試料汚泥の強熱減量を再評価用計測値として算出する。
【００１３】
これは、計測装置の配管内に残留している同じ計測対象汚泥から評価用試料汚泥を採取するので、含水率は基本的に同様であると推量でき、仮に異物が混じった例外的な試料汚泥を採取した場合は、含水率も正しく計測されず、強熱減量も実際からの誤差が大きくなり、再評価用計測値と本計測値との差違が明確に判断できるためであり、再評価用計測値の算出に本計測における含水率を用いても問題はない。
【００１４】
この再評価用計測値と本計測値との差分である二次評価値が再評価基準値より大きければ、例えば１％以上であれば、本計測値は例外的で異常な試料汚泥に基づくものであって、汚泥供給源における汚泥性状を適切に反映するものではないとして、計測結果の出力を保留する。
二次評価値が再評価基準値未満である場合には、つまり許容精度内であれば本計測値は汚泥供給源における汚泥性状の変化を正しく捉えていたものと判断して出力値を更新する。
【００１５】
本計測値の大きな変化を検出した場合に、乾燥工程を行なわずに強熱灰化工程のみの評価計測によって本計測値の正当性を評価することができ、従来のように、次回の計測終了時まで（１００分前後の期間）不正確な計測結果を出力し続けてしまうことが無くなり、あるいは前回計測値を再び保留し続けることもないので、汚泥性状の変化の正当性を短期間（１５〜３０分）の再評価操作で判断することができ、常に正しい計測値を出力することができる。
【００１６】
【発明の実施の形態】
以下、本発明の実施の形態を図面に基づいて説明する。図１において、計測装置１は計測装置本体２と計測制御盤３とからなり、計測装置本体２は汚泥採取室４、加熱計量室５、電子天秤室６、廃棄室７に区画してそれぞれ閉塞空間を形成している。
【００１７】
電子天秤室６には計測機器として電子天秤８を配置し、電子天秤８の天秤皿９を加熱計量室５の内部に配置し、この天秤皿９に試料汚泥１０を採取する試料皿１１を載置している。加熱計量室５は、上部に熱源としてのハロゲンランプ装置１２を配置し、側壁面上部に脱臭ファン１３を設けており、一側の壁面に形成した開口５ａを開閉する扉装置１４を有している。
【００１８】
汚泥採取室４には、試料皿１１をハンドリングするためのロボットハンド１５を配置するとともに、試料汚泥１０を供給する汚泥供給系１６と、計測後の残留物を吸引除去する吸引系１７と、汚泥供給系１６に残る余剰な汚泥を投棄する排水系１８とがそれぞれ開口している。
汚泥供給系１６は、途中に給泥ポンプ１９と開閉バルブ２０を有し、先端に鉛直方向の供給口２１を有しており、供給口２１には試料汚泥１０を圧縮空気で押し出す圧縮空気供給系２２が連通している。吸引系１７は廃棄室７に配置した吸引ブロア２３および集灰缶２４を有し、排水系１８は廃棄室７に配置した攪拌槽２５および排水ポンプ２６を有している。
【００１９】
これらの機器を制御する計測制御盤３は、ハロゲンランプ装置１２の出力を制御するランプコントローラ２７と、ランプコントローラ２７への指示量を調節する指示調節計２８と、パーソナルコンピュータ２９からなり、パーソナルコンピュータ２９は、加熱計量室５に配置した温度センサー３０および電子天秤８からの出力を受け取り、各機器を制御して計測操作を行なう。
【００２０】
以下、上記した構成における作用を説明する。図２に計測操作の手順を示す。試料に供する汚泥は、焼却、溶融処理プラントへ汚泥を供給する本管（図示省略）から汚泥供給系１６を通して取り出す。この汚泥の取出操作は給泥ポンプ１９を駆動して連続的に行なって本管を流れる汚泥と同質の汚泥をリアルタイムに取り込み、試料として採取しない汚泥を排水系１８に投入している。
【００２１】
計測操作の１サイクルの初期状態において試料皿１１は加熱計量室５の天秤皿９の上にある。この試料皿１１の重量を電子天秤８で計測し、この計測値を皿重量Ｗ_０として取得する。開閉バルブ２０を一旦閉栓し、供給口２１に残留する汚泥を圧縮空気供給系２２から供給する圧縮空気によって排出する。加熱計量室５の扉装置１４を開放し、ロボットハンド１５を操作して試料皿１１を採取位置へ移動する。
【００２２】
開閉バルブ２０を所定時間だけ開放して所定量の試料汚泥１０を供給口２１から試料皿１１へ供給し、供給口２１に残留する汚泥を圧縮空気供給系２２から供給する圧縮空気によって排出する。扉装置１４を開放し、試料汚泥１０を採取した試料皿１１をロボットハンド１５で天秤皿９に載置する。
扉装置１４を閉じて電子天秤８によって採取した試料汚泥の重量を計測し、計測値Ｗｓ_１（汚泥試料重量Ｗ_１＋皿重量Ｗ_０）を記憶する。以後連続して重量を計測する。ランプコントローラ２７はハロゲンランプ装置１２を所定の出力で点灯し、試料汚泥１０を乾燥する乾燥工程を行う。この乾燥工程では、試料汚泥が乾燥温度（１０５〜１１０℃）となるように加熱し、乾燥工程の終了時に電子天秤８が示す計測値Ｗｓ_２（全蒸発残留物重量Ｗ_２＋皿重量Ｗ_０）を取得する。
【００２３】
指示調節計２８によりハロゲンランプ装置１２の出力を増し、試料皿１１に残る蒸発残留物を強熱灰化する。強熱灰化工程では、試料汚泥が強熱灰化温度（６００±２５℃）となるように加熱し、試料汚泥１０を強熱灰化し、強熱灰化工程の終了時に電子天秤８が示す計測値Ｗｓ_３（強熱残留物重量Ｗ_３＋皿重量Ｗ_０）を取得する。
【００２４】
そして、パーソナルコンピュータ２９は、含水率αと強熱減量β（％）とを次式において求める。
（Ｗｓ_１−Ｗｓ_２）／（Ｗｓ_１−Ｗ_０）×１００＝α
（Ｗｓ_２−Ｗｓ_３）／（Ｗｓ_２−Ｗ_０）×１００＝β
このように、毎回の計測操作時に汚泥供給源である本管から計測対象汚泥を取り込み、試料汚泥を採取して強熱減量βを計測することにより、汚泥供給源における汚泥性状の経時的変化を計測する。
【００２５】
次に、本計測の正当性を評価する。このため、算出した強熱減量を本計測値βとして記録し、前回計測値βｐに対する本計測値βの変動量｜β−βｐ｜を一次評価値として求め、予め設定する評価基準値、例えば１％と比較して一次評価する。一次評価値が評価基準値未満である場合には、本計測値βを正常計測値と評価し、前回に出力した計測値βｐを本計測値βに更新する。
【００２６】
本計測値βが前回計測値βｐから大きく変化して、一次評価値が評価基準量の１％以上である場合、および前回の計測値が得られていない初回の計測操作時の場合には、本計測値βの正当性を二次評価するために評価用計測値を求める。
この評価計測においては、本管から新たな計測対象汚泥の取り込みを行なわずに、計測装置の汚泥供給系１６に残留している同じ計測対象汚泥から評価用試料汚泥を前述した手順と同様にして再度採取する。このことにより、評価用試料汚泥が本計測の試料汚泥と同じ汚泥性状となるので、評価用試料汚泥の強熱減量と本計測の強熱減量とを比較することは、本計測値βの計測精度を検証することになる。
【００２７】
評価計測では前述した手順と同様にして評価用試料汚泥の重量Ｗ_１’を計測し、乾燥工程を行なわずに直ちに、強熱灰化工程を行なって強熱残留物の重量Ｗ_３’を計測し、次式において評価用試料汚泥の強熱減量β’を再評価用計測値として算出する。
β’＝［Ｗ_１’（１−α／１００）−Ｗ_３’］／Ｗ_１’（１−α／１００）×１００
ここでは、評価用試料汚泥の含水率は先に本計測で得た含水率αと同じであるとして、評価用試料汚泥の重量Ｗ_１’に本計測の含水率αを乗算して全蒸発物重量（Ｗ_１’×α／１００）を求め、評価用試料汚泥の重量Ｗ_１’から全蒸発物重量（Ｗ_１’×α／１００）を減算して評価用試料汚泥における全蒸発残留物の重量Ｗ_１’（１−α／１００）を算出している。
【００２８】
これは、計測装置の配管内に残留している同じ計測対象汚泥から評価用試料汚泥を採取するので、含水率は基本的に同様であると推量できるためであり、また、仮に異物が混じった例外的な試料汚泥を採取した場合は、含水率αも正しく計測されず、強熱減量βも実際からの誤差が大きくなり、再評価用計測値β’と本計測値βとの差違が明確に判断できるためであり、再評価用計測値β’の算出に本計測における含水率αを用いても問題はない。
【００２９】
再評価用計測値β’と本計測値βとの差分を二次評価値｜β−β’｜として求めて二次評価する。二次評価値｜β−β’｜が予め設定する再評価基準値、例えば１％未満である場合には、本計測値は許容精度内にあり、本管における汚泥性状の変化を正しく捉えているとして、本計測値βを正常計測値と評価し、前回に出力した計測値βｐを本計測値βに更新する。
【００３０】
二次評価値｜β−β’｜が再評価基準値より大きければ、例えば１％以上である場合には、本計測値βは例外的で異常な試料汚泥に基づくものであって、本管における汚泥性状を適切に反映するものではなく、異常計測値であると判断して次回の計測値が確定するまで計測結果の出力を保留する。
計測終了後に、ロボットハンド１５により試料皿１１を加熱計量室５から取り出し、試料皿１１を廃棄位置で吸引系１７に対応させる。吸引ブロア２３を駆動して試料皿１１の強熱残留物を吸引除去し、吸引した灰を集灰缶２４に貯留する。加熱計量室５の扉装置１４を開放し、ロボットハンド１５により試料皿１１をの天秤皿の計測位置に戻す。その後、脱臭ファン１３による加熱計量室５の空気を排気することにより加熱計量室５および試料皿１１を冷却し、初期状態に復帰して、本管から新たに計測対象汚泥を汚泥供給系１６に取り込んで、計測操作を繰り返す。
【００３１】
【発明の効果】
以上のように、本発明によれば、本計測値の大きな変化を検出した場合に、乾燥工程を行なわずに強熱灰化工程のみの評価計測によって本計測値の正当性を評価することができ、従来のように、次回の計測終了時まで（１００分前後の期間）不正確な計測結果を出力し続けてしまうことが無くなり、あるいは前回計測値を再び保留し続けることもないので、汚泥性状の変化の正当性を短期間（１５〜３０分）の再評価操作で判断することができ、常に正しい計測値を出力することができる。
【図面の簡単な説明】
【図１】本発明の実施の形態を示す計測装置の摸式図である。
【図２】同実施の形態における計測手順を示すフローシートである。
【符号の説明】
１計測装置
５加熱計量室
８電子天秤
９天秤皿
１０試料汚泥
１１試料皿
１２ハロゲンランプ装置
１３脱臭ファン
１４扉装置
１５ロボットハンド
２７ランプコントローラ
２８指示調節計
２９パーソナルコンピュータ
Ｗ_０皿重量
Ｗ_１試料汚泥の重量
Ｗ_２全蒸発残留物重量
Ｗ_３強熱残留物重量
Ｗ_１’ 評価用試料汚泥の重量
Ｗ_２’ 評価用試料汚泥の全蒸発残留物重量
Ｗ_３’ 評価用試料汚泥の強熱残留物重量
β 本計測値（強熱減量）
β’ 評価用計測値（強熱減量）[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a sludge ignition loss measurement method, and is a technology related to a sludge analyzer used in a sludge melting furnace or the like.
[0002]
[Prior art]
In recent years, sewage treatment facilities tend to employ wide-area sludge treatment for the purpose of efficient disposal of sludge. However, the sludge properties that are carried in easily change over time and affect the stable operation of the incineration and melting treatment plants. Measuring the moisture content of the sludge and the loss on ignition in advance in such a treatment plant is important for stable operation of the plant.
[0003]
This measurement is performed based on a test method defined by the Japan Sewerage Association. For the moisture, the sample sludge is dried at 105 to 110 ° C. for 2 hours, the weight of the total evaporation residue after the lapse is measured, and the difference from the weight of the sample sludge before drying is calculated. For ignition loss, the total evaporation residue after moisture content measurement is ashed at 600 ± 25 ° C for 1 hour, and the weight of the ignition residue after the lapse of time is measured, and the difference from the weight of the total evaporation residue is calculated. calculate.
[0004]
In a conventional measuring device for sludge moisture content and loss on ignition, a sample in which sludge is drawn into a measuring device from a sludge main pipe that supplies sludge to a melting furnace, and sample sludge (5 g) is weighed in advance from the drawn sludge Collect in a dish and first weigh the sample sludge in the heating and weighing chamber. Next, the moisture in the sample sludge is evaporated by heating in the drying process, after which the weight of the total evaporation residue is measured, and the difference between this measured value and the weight of the sample sludge before drying is calculated to obtain the moisture content. Then, the moisture content is calculated by dividing the moisture content by the weight of the sample sludge before drying. Subsequently, it is burned by heating in the ignition ashing step, after which the weight of the ignition residue is measured, and the difference between this measured value and the weight of the total evaporation residue is calculated as ignition loss.
[0005]
When this series of measurement processing steps is completed, the process returns to the beginning of the measurement operation cycle, discards the sludge drawn in the previous time, newly draws the sludge from the main mud pipe into the measuring device, and repeats the measurement operation. Each time one measurement operation is completed, the measurement result is transmitted to the outside and the measurement output value is updated.
[0006]
[Problems to be solved by the invention]
In the conventional configuration described above, if the moisture content is 80% in 5 g of sample sludge, the weight of the total evaporation residue after drying is 1 g. In order to measure the loss on ignition in the subsequent ignition ashing process with an accuracy of 1%, a measurement error of 10 mg or more is not allowed in the measurement of the weight of the ignition residue.
[0007]
By the way, the collected sample sludge is rarely mixed with solid foreign matters such as stone fragments, and in this case, an accurate measurement result cannot be obtained. However, it cannot be determined from the measurement result itself whether the measurement value is a normal value reflecting a change in sludge properties or an abnormal value due to solid foreign matter. For this reason, if the measurement result is output as it is, the operation of the melting furnace or the like is performed based on an incorrect value until the next measurement result is obtained.
[0008]
This invention solves an above-described subject, and it aims at providing the ignition loss measuring method which evaluates a measurement result within a short time.
[0009]
[Means for solving the problems]
In order to solve the above problems, the ignition loss measurement method of the present invention takes an appropriate amount of measurement sludge from a sludge supply source at the beginning of each measurement operation, and collects a predetermined amount of sample sludge from the measurement sludge. Measure the weight of the sample sludge before drying, the weight of the total evaporation residue after the drying process, and the weight of the ignition residue after the ignition ashing process. Divide the moisture content, which is the difference from the weight, by the weight of the sample sludge to obtain the moisture content of the sample sludge, and divide the difference between the weight of the total evaporation residue and the weight of the ignition residue by the weight of the total evaporation residue. In the ignition loss measurement method for calculating the ignition loss, the calculated ignition loss is recorded as the actual measurement value, and the amount of fluctuation of the actual measurement value with respect to the previous measurement value is obtained as the primary evaluation value. If it is less than the evaluation reference value to be set, this measurement value is evaluated as a normal measurement value. When the primary evaluation value is equal to or greater than the evaluation reference amount and during the first measurement operation, a predetermined amount of sample sludge for evaluation is newly collected from the same measurement target sludge, and evaluation measurement is performed. The total evaporation residue of the sample sludge for evaluation is measured based on the weight of the sample sludge after the ignition ashing process and based on the weight of the sample sludge for evaluation and the moisture content obtained during the measurement. The weight of the product is calculated, and the loss on ignition, which is the difference between the weight of the total evaporation residue and the weight of the ignition residue in the sample sludge for evaluation, is calculated as the measurement value for re-evaluation. The difference from the measured value is obtained as a secondary evaluation value, and if the secondary evaluation value is less than the preset re-evaluation reference value, this measurement value is evaluated as a normal measurement value, and the secondary evaluation value is reevaluated. If it is above the reference value, this measured value is judged as an abnormal measured value and sludge In which again performs measurement operation fetches the new measurement target sludge from sources.
[0010]
With the above-described configuration, the time-dependent change in the sludge property in the sludge supply source is measured by taking the measurement target sludge from the sludge supply source during each measurement operation, collecting the sample sludge, and measuring the loss on ignition.
When the measurement result of each measurement operation is primarily evaluated and the measured value of ignition loss greatly changes from the previous measured value, for example, the current measured value has a fluctuation amount of 1% or more with respect to the previous measured value. In this case, or in the case of the first measurement operation for which the previous measured value is not obtained, the measured value measured this time is used as the actual measured value in order to secondarily evaluate the validity of the measured value of the ignition loss measured. As a result, the measurement value for evaluation is obtained.
[0011]
In the measurement of the measurement values for evaluation, the sludge is not taken in from the main pipe (sludge supply source) that supplies sludge to the melting furnace or the like, but remains in the pipe of the measuring device. Collect the sample sludge for evaluation again from the same measurement target sludge. As a result, the sample sludge for evaluation has the same sludge properties as the sample sludge for this measurement, so comparing the ignition loss of the sample sludge for evaluation with the ignition loss for this measurement increases the measurement accuracy of this measurement. Will be verified.
[0012]
In the evaluation measurement operation, after the weight of the sample sludge for evaluation is measured, the weight of the ignition residue is measured by ashing in the ignition ashing process immediately without performing the drying process. Then, assuming that the moisture content of the evaluation sample sludge is the same as the value obtained in the previous measurement, the weight of the evaluation sample sludge is multiplied by the moisture content of the measurement to obtain the total evaporate weight, and the evaluation sample The total evaporant weight is subtracted from the sludge weight to calculate the total evaporation residue weight in the sample sludge for evaluation, and the loss on ignition of the sample sludge for evaluation is calculated as a measurement value for re-evaluation.
[0013]
This is because the sample sludge for evaluation is collected from the same sludge to be measured remaining in the piping of the measuring device, so it can be assumed that the moisture content is basically the same, and exceptional sample sludge mixed with foreign matters is assumed. This is because the moisture content is not measured correctly, and the actual loss of ignition increases greatly, and the difference between the measured value for re-evaluation and this measured value can be clearly determined. There is no problem even if the moisture content in the main measurement is used for the calculation of the measurement value.
[0014]
If the secondary evaluation value, which is the difference between the measured value for reevaluation and the measured value, is larger than the reevaluation reference value, for example, 1% or more, the measured value is based on exceptional and abnormal sample sludge. However, the output of the measurement result is suspended because the sludge property in the sludge supply source is not appropriately reflected.
If the secondary evaluation value is less than the re-evaluation reference value, that is, if it is within the permissible accuracy, it is judged that this measurement value correctly captured the change in sludge properties at the sludge supply source, and the output value is updated. .
[0015]
When a large change in the measured value is detected, the validity of the measured value can be evaluated by evaluating and measuring only the ignition ash process without performing the drying process. Inaccurate measurement results will not continue to be output until time (a period of about 100 minutes), or the previous measurement value will not be held again, so the change in sludge properties can be justified for a short period (15 (~ 30 minutes) can be determined by a re-evaluation operation, and a correct measurement value can always be output.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. In FIG. 1, the measuring device 1 includes a measuring device main body 2 and a measurement control panel 3, and the measuring device main body 2 is partitioned into a sludge collection chamber 4, a heating and weighing chamber 5, an electronic balance chamber 6, and a disposal chamber 7. A space is formed.
[0017]
An electronic balance 8 is arranged as a measuring device in the electronic balance chamber 6, a balance pan 9 of the electronic balance 8 is placed inside the heating weighing chamber 5, and a sample pan 11 for collecting the sample sludge 10 is placed on the balance pan 9. It is location. The heating metering chamber 5 has a halogen lamp device 12 as a heat source at the top, a deodorizing fan 13 at the top of the side wall surface, and a door device 14 for opening and closing an opening 5a formed on one side wall surface. Yes.
[0018]
In the sludge collection chamber 4, a robot hand 15 for handling the sample dish 11 is arranged, a sludge supply system 16 for supplying the sample sludge 10, a suction system 17 for sucking and removing the residue after measurement, and sludge A drainage system 18 for dumping excess sludge remaining in the supply system 16 is opened.
The sludge supply system 16 has a mud supply pump 19 and an open / close valve 20 in the middle, and has a supply port 21 in the vertical direction at the tip, and the supply port 21 is supplied with compressed air to push the sample sludge 10 with compressed air. The system 22 is in communication. The suction system 17 has a suction blower 23 and an ash collecting can 24 disposed in the disposal chamber 7, and the drainage system 18 has a stirring tank 25 and a drainage pump 26 disposed in the disposal chamber 7.
[0019]
The measurement control panel 3 that controls these devices includes a lamp controller 27 that controls the output of the halogen lamp device 12, an instruction controller 28 that adjusts an instruction amount to the lamp controller 27, and a personal computer 29. 29 receives the output from the temperature sensor 30 and the electronic balance 8 disposed in the heating and weighing chamber 5, and controls each device to perform a measurement operation.
[0020]
Hereinafter, the operation of the above-described configuration will be described. FIG. 2 shows the procedure of the measurement operation. The sludge used for the sample is taken out through a sludge supply system 16 from a main pipe (not shown) that supplies the sludge to the incineration and melting treatment plant. This sludge extraction operation is continuously performed by driving the feed pump 19 to take in real time sludge of the same quality as the sludge flowing through the main pipe, and throwing in the drainage system 18 sludge not collected as a sample.
[0021]
In the initial state of one cycle of the measurement operation, the sample pan 11 is on the balance pan 9 in the heating and weighing chamber 5. The weight of the sample pan 11 is measured by the electronic balance 8, to obtain the measurement value as a pan weight W _0. The on-off valve 20 is once closed, and the sludge remaining in the supply port 21 is discharged by the compressed air supplied from the compressed air supply system 22. The door device 14 of the heating and measuring chamber 5 is opened, and the robot hand 15 is operated to move the sample dish 11 to the collection position.
[0022]
The on-off valve 20 is opened for a predetermined time to supply a predetermined amount of sample sludge 10 from the supply port 21 to the sample pan 11, and the sludge remaining in the supply port 21 is discharged by compressed air supplied from the compressed air supply system 22. The door device 14 is opened, and the sample pan 11 from which the sample sludge 10 has been collected is placed on the balance pan 9 by the robot hand 15.
The door device 14 is closed and the weight of the sample sludge collected by the electronic balance 8 is measured, and the measured value Ws ₁ (sludge sample weight W ₁ + dish weight W ₀ ) is stored. Thereafter, the weight is continuously measured. The lamp controller 27 turns on the halogen lamp device 12 with a predetermined output and performs a drying process for drying the sample sludge 10. In this drying step, the sample sludge is heated to a drying temperature (105 to 110 ° C.), and the measured value Ws ₂ (total evaporation residue weight W ₂ + dish weight W ₀₎ indicated by the electronic balance 8 at the end of the drying step. ) To get.
[0023]
The output of the halogen lamp device 12 is increased by the indicator controller 28, and the evaporation residue remaining in the sample pan 11 is ignited with high heat. In the ignition ashing step, the sample sludge is heated to an ignition ashing temperature (600 ± 25 ° C.) to ignite the sample sludge 10 and the electronic balance 8 indicates at the end of the ignition ashing step. The measured value Ws ₃ (ignition residue weight W ₃ + dish weight W ₀ ) is acquired.
[0024]
And the personal computer 29 calculates | requires the moisture content (alpha) and the ignition loss (beta) (%) in following Formula.
(Ws ₁ −Ws ₂ ) / (Ws ₁ −W ₀ ) × 100 = α
(Ws ₂ −Ws ₃ ) / (Ws ₂ −W ₀ ) × 100 = β
In this way, by taking the measurement target sludge from the main, which is the sludge supply source, at each measurement operation, collecting the sample sludge and measuring the loss on ignition β, the sludge properties at the sludge supply source over time can be changed. measure.
[0025]
Next, the validity of this measurement is evaluated. For this reason, the calculated ignition loss is recorded as the main measurement value β, the fluctuation amount | β−βp | of the main measurement value β with respect to the previous measurement value βp is obtained as a primary evaluation value, and a preset evaluation reference value, for example, 1 Primary evaluation compared to%. When the primary evaluation value is less than the evaluation reference value, the main measurement value β is evaluated as a normal measurement value, and the measurement value βp output last time is updated to the main measurement value β.
[0026]
When the main measurement value β is greatly changed from the previous measurement value βp and the primary evaluation value is 1% or more of the evaluation reference amount, and at the time of the first measurement operation in which the previous measurement value is not obtained, An evaluation measurement value is obtained in order to secondarily evaluate the validity of the measurement value β.
In this evaluation measurement, the sample sludge for evaluation is made from the same measurement target sludge remaining in the sludge supply system 16 of the measurement apparatus without taking in the new measurement target sludge from the main pipe in the same manner as described above. Collect again. As a result, the sample sludge for evaluation has the same sludge properties as the sample sludge for this measurement, so comparing the ignition loss of the sample sludge for evaluation with the ignition loss for this measurement is the measurement of this measurement value β. The accuracy will be verified.
[0027]
In the evaluation measurement, the weight W ₁ ′ of the sample sludge for evaluation is measured in the same manner as described above, and the ignition ashing process is immediately performed without performing the drying process, and the weight W ₃ ′ of the ignition residue is measured. Then, the ignition loss β ′ of the sample sludge for evaluation is calculated as a re-evaluation measurement value in the following equation.
β ′ = [W ₁ ′ (1−α / 100) −W ₃ ′] / W ₁ ′ (1−α / 100) × 100
Here, assuming that the moisture content of the evaluation sample sludge is the same as the moisture content α previously obtained in this measurement, the total evaporate is obtained by multiplying the weight W ₁ ′ of the evaluation sample sludge by the moisture content α in this measurement. The weight (W ₁ ′ × α / 100) is obtained, and the total evaporation residue in the evaluation sample sludge is obtained by subtracting the total evaporate weight (W ₁ ′ × α / 100) from the evaluation sample sludge weight W ₁ ′. The weight W ₁ ′ (1−α / 100) is calculated.
[0028]
This is because the sample sludge for evaluation is collected from the same sludge to be measured remaining in the piping of the measuring device, so that it can be assumed that the moisture content is basically the same, and foreign matter is temporarily mixed. When exceptional sample sludge is collected, the moisture content α is not correctly measured, and the ignition loss β is also significantly different from the actual value. The difference between the measured value β ′ for re-evaluation and the actual measured value β is clear. Therefore, there is no problem even if the moisture content α in the main measurement is used for the calculation of the re-evaluation measurement value β ′.
[0029]
The difference between the measurement value β ′ for re-evaluation and the actual measurement value β is obtained as a secondary evaluation value | β−β ′ | and subjected to secondary evaluation. When the secondary evaluation value | β−β ′ | is less than a preset re-evaluation reference value, for example, less than 1%, the measured value is within the allowable accuracy, and the change in sludge properties in the main pipe is correctly captured. As a result, the main measurement value β is evaluated as a normal measurement value, and the measurement value βp output last time is updated to the main measurement value β.
[0030]
If the secondary evaluation value | β−β ′ | is larger than the re-evaluation reference value, for example, if it is 1% or more, the measured value β is based on exceptional and abnormal sample sludge. The sludge properties are not properly reflected, and the measurement result is determined to be an abnormal measurement value, and the output of the measurement result is suspended until the next measurement value is determined.
After completion of the measurement, the sample pan 11 is taken out from the heating and weighing chamber 5 by the robot hand 15, and the sample pan 11 is made to correspond to the suction system 17 at the disposal position. The suction blower 23 is driven to remove the ignition residue on the sample dish 11 and the sucked ash is stored in the ash collecting can 24. The door device 14 of the heating and weighing chamber 5 is opened, and the sample pan 11 is returned to the measuring position of the balance pan by the robot hand 15. Thereafter, the heating metering chamber 5 and the sample pan 11 are cooled by exhausting the air in the heating metering chamber 5 by the deodorizing fan 13, the initial state is restored, and the measurement target sludge is newly supplied from the main to the sludge supply system 16. Capture and repeat the measurement operation.
[0031]
【The invention's effect】
As described above, according to the present invention, when a large change in the main measurement value is detected, the validity of the main measurement value can be evaluated by the evaluation measurement only of the ignition ash process without performing the drying process. As in the past, inaccurate measurement results will not continue to be output until the end of the next measurement (a period of about 100 minutes), or the previous measurement value will not continue to be held again. The correctness of the property change can be determined by a short-term (15 to 30 minutes) re-evaluation operation, and a correct measurement value can always be output.
[Brief description of the drawings]
FIG. 1 is a schematic diagram of a measuring apparatus showing an embodiment of the present invention.
FIG. 2 is a flow sheet showing a measurement procedure in the embodiment.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Measuring device 5 Heating weighing chamber 8 Electronic balance 9 Balance pan 10 Sample sludge 11 Sample tray 12 Halogen lamp device 13 Deodorizing fan 14 Door device 15 Robot hand 27 Lamp controller 28 Indicator controller 29 Personal computer W ₀ Plate weight W ₁ Sample sludge Weight W ₂ total evaporation residue weight W ₃ ignition residue weight W ₁ 'evaluation sample sludge weight W ₂ ' evaluation sample sludge total evaporation residue weight W ₃ 'evaluation sample sludge ignition residue Weight β This measured value (loss on ignition)
β 'Measured value for evaluation (loss on ignition)

Claims

毎回の計測操作の始めに汚泥供給源から適当量の計測対象汚泥を取り込み、計測対象汚泥から所定量の試料汚泥を採取し、乾燥前の試料汚泥の重量と、乾燥工程後の全蒸発残留物の重量と、強熱灰化工程後の強熱残留物の重量とを計測し、試料汚泥の重量と全蒸発残留物の重量との差分である水分量を試料汚泥の重量で除算して試料汚泥の含水率を求め、全蒸発残留物の重量と強熱残留物の重量との差分を全蒸発残留物の重量で除算して強熱減量を算出する強熱減量計測方法において、
算出した強熱減量を本計測値として記録し、前回計測値に対する本計測値の変動量を一次評価値として求め、一次評価値が予め設定する評価基準値未満である場合には、本計測値を正常計測値と評価し、
一次評価値が評価基準量以上である場合および初回の計測操作時には、同じ計測対象汚泥から新たに所定量の評価用試料汚泥を採取して評価計測を行ない、評価計測において評価用試料汚泥の重量と、強熱灰化工程後の強熱残留物の重量を計測し、評価用試料汚泥の重量と本計測値の計測時に求めた含水率とに基づいて評価用試料汚泥の全蒸発残留物の重量を算出し、評価用試料汚泥における全蒸発残留物の重量と強熱残留物の重量との差分である強熱減量を再評価用計測値として算出し、
再評価用計測値と本計測値との差分を二次評価値として求め、二次評価値が予め設定する再評価基準値未満である場合には、本計測値を正常計測値と評価し、二次評価値が再評価基準値以上である場合には、本計測値を異常計測値と判断し、汚泥供給源から新たに計測対象汚泥を取り込んで改めて計測操作を行なうことを特徴とする汚泥の強熱減量計測方法。At the beginning of each measurement operation, an appropriate amount of measurement sludge is taken from the sludge supply source, a predetermined amount of sample sludge is collected from the measurement sludge, the weight of the sample sludge before drying, and the total evaporation residue after the drying process The weight of the residue and the weight of the ignition residue after the ashing process are measured, and the sample is obtained by dividing the moisture content, which is the difference between the sample sludge weight and the total evaporation residue weight, by the sample sludge weight. In the ignition loss measurement method that calculates moisture loss by calculating the moisture content of sludge and dividing the difference between the weight of the total evaporation residue and the weight of the ignition residue by the weight of the total evaporation residue,
The calculated loss on ignition is recorded as the actual measurement value, the amount of fluctuation of the actual measurement value with respect to the previous measurement value is obtained as the primary evaluation value, and if the primary evaluation value is less than the preset evaluation reference value, the actual measurement value Is evaluated as a normal measurement value,
When the primary evaluation value is equal to or greater than the evaluation reference amount and at the first measurement operation, a new amount of sample sludge for evaluation is newly collected from the same sludge to be measured, and evaluation measurement is performed. And the weight of the ignition residue after the ignition ashing process, and the total evaporation residue of the evaluation sample sludge based on the weight of the evaluation sample sludge and the moisture content obtained at the time of the measurement. Calculate the weight, calculate the loss on ignition, which is the difference between the weight of the total evaporation residue and the weight of the ignition residue in the sample sludge for evaluation, as the measurement value for re-evaluation,
The difference between the measurement value for re-evaluation and the main measurement value is obtained as a secondary evaluation value.If the secondary evaluation value is less than the preset re-evaluation reference value, the main measurement value is evaluated as a normal measurement value, When the secondary evaluation value is equal to or higher than the re-evaluation reference value, this measurement value is judged to be an abnormal measurement value, and the measurement operation is performed by newly taking the measurement target sludge from the sludge supply source. Ignition loss measurement method.