JP4707635B2 - Method and apparatus for monitoring the bottom of melting furnace - Google Patents

Method and apparatus for monitoring the bottom of melting furnace Download PDF

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JP4707635B2
JP4707635B2 JP2006249976A JP2006249976A JP4707635B2 JP 4707635 B2 JP4707635 B2 JP 4707635B2 JP 2006249976 A JP2006249976 A JP 2006249976A JP 2006249976 A JP2006249976 A JP 2006249976A JP 4707635 B2 JP4707635 B2 JP 4707635B2
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忠八 五島
野間　　彰
敬太 井上
佳正 川見
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Mitsubishi Heavy Industries Environmental and Chemical Engineering Co Ltd
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Description

本発明は、炉底ケーシング温度に基づいて炉底耐火材の侵食や損傷等の炉底異常を監視する溶融炉の炉底監視方法及び装置に関する。   The present invention relates to a melting furnace bottom monitoring method and apparatus for monitoring a bottom abnormality such as erosion or damage of a bottom refractory based on a bottom casing temperature.

廃棄物を溶融処理する溶融炉は、廃棄物の無害化、減容化及び資源化の観点からその必要性が高まりつつある。溶融炉には、重油等を燃料として被処理物を溶融するバーナ式溶融炉や、電気を熱源として被処理物を溶融する電気抵抗式溶融炉及びプラズマ式溶融炉等が知られている。
一例として、プラズマ式溶融炉につき図１０を参照して説明する。プラズマ式溶融炉５０は、炉頂部から垂下される主電極５１と、炉底５９に配設される炉底電極５２とを有し、これらの両電極間に直流電圧５３を印加することによりプラズマアークを発生する。そして、投入ホッパ５５より炉本体５４内に投下された被処理物をプラズマ熱により加熱して溶融する。被処理物は溶融して溶融スラグ５６と、これより比重が大である溶融メタル５７が炉本体５４内に溜まり、出滓口５８より排出される。炉本体５４内は高温に維持されるため、その内部は耐火材６０により形成され、この耐火材６０を鋼板製のケーシング６３により被覆した構造となっている。炉底の耐火構造は、溶融メタルに接触する内側は侵食に強いアーチ状レンガ６１を配設し、このレンガ６１とケーシング６３の間に耐火レンガ６２を配設した構成などがある。 The need for melting furnaces for melting waste is increasing from the viewpoint of detoxification, volume reduction, and resource recycling of waste. Known melting furnaces include a burner type melting furnace for melting an object to be processed using heavy oil or the like as a fuel, an electric resistance type melting furnace and a plasma type melting furnace for melting an object to be processed using electricity as a heat source.
As an example, a plasma melting furnace will be described with reference to FIG. The plasma melting furnace 50 has a main electrode 51 suspended from the top of the furnace and a furnace bottom electrode 52 disposed on the furnace bottom 59, and a plasma is generated by applying a DC voltage 53 between these two electrodes. Generate an arc. And the to-be-processed object dropped in the furnace main body 54 from the charging hopper 55 is heated and melted by plasma heat. The object to be processed is melted and molten slag 56 and molten metal 57 having a specific gravity larger than that are accumulated in the furnace main body 54 and discharged from the outlet 58. Since the inside of the furnace main body 54 is maintained at a high temperature, the inside of the furnace body 54 is formed of a refractory material 60, and the refractory material 60 is covered with a steel plate casing 63. The fireproof structure of the bottom of the furnace includes a configuration in which an arch-like brick 61 that is resistant to erosion is disposed on the inner side in contact with the molten metal, and a refractory brick 62 is disposed between the brick 61 and the casing 63.

このような溶融炉においては、炉内から溶融メタルや溶融スラグが漏れ出す可能性があり、水蒸気爆発等の危険性があることから炉底は水冷却しない場合が多い。しかし、自然空冷の場合は冷却が弱く、水冷構造を有していない炉底耐火物はメタルやスラグによって侵食されてしまう。一般に、侵食の進行は、耐火物同士を固着させる目地から発生し、目地の侵食が進むと耐火レンガの固定が劣弱となりメタルより比重の小さい耐火レンガが剥離してメタル中に浮き上がる。耐火レンガは剥離部を中心として徐々に拡大し、該剥離部近傍の炉底ケーシングの温度は上昇する。ケーシングは、耐熱温度以上（３５０℃程度）まで昇温すると変形、抜け落ち等の不具合が発生してしまう惧れがある。従って、炉底の鉄皮温度を監視する必要がある。   In such a melting furnace, there is a possibility that molten metal or molten slag leaks from the inside of the furnace, and there is a risk of a steam explosion or the like, so the furnace bottom is often not cooled with water. However, in the case of natural air cooling, the cooling is weak and the bottom refractory that does not have a water cooling structure is eroded by metal or slag. In general, the progress of erosion occurs from the joint where the refractories adhere to each other. When the erosion of the joint progresses, the fixing of the refractory brick becomes poor, and the refractory brick having a specific gravity smaller than that of the metal peels off and floats in the metal. The refractory brick gradually expands around the peeling part, and the temperature of the furnace bottom casing near the peeling part rises. If the casing is heated to a temperature higher than the heat-resistant temperature (about 350 ° C.), there is a possibility that problems such as deformation and dropout may occur. Therefore, it is necessary to monitor the furnace skin temperature at the bottom of the furnace.

炉体温度の測定には、特許文献１（特開平１１−２１８３２０号公報）に記載されるように、炉本体底部から耐火物に貫通するごとく熱電対６５（図１０参照）を設置し、耐火物の温度を測定したり、炉底ケーシングに温度センサを設置して炉底表面の温度を測定する方法が一般的であった。温度センサとしては、熱電対やサーモグラフィ装置が用いられることが多い。
また、特許文献２（特開２００１−４２８３号公報）には、測定した温度情報に基づいて耐火材層の検査を行う方法が開示されている。これは、ロータリーキルンのレンガ壁の壁中及び壁外に温度センサを設け、得られた温度検出信号に基づいて耐火材層の厚さ若しくは内部状況を監視するものである。 For the measurement of the furnace body temperature, as described in Patent Document 1 (Japanese Patent Laid-Open No. 11-218320), a thermocouple 65 (see FIG. 10) is installed so as to penetrate the refractory from the bottom of the furnace main body. A general method is to measure the temperature of an object or to measure the temperature of the furnace bottom surface by installing a temperature sensor in the furnace bottom casing. As the temperature sensor, a thermocouple or a thermography device is often used.
Patent Document 2 (Japanese Patent Laid-Open No. 2001-4283) discloses a method for inspecting a refractory material layer based on measured temperature information. In this method, temperature sensors are provided in and outside the brick wall of the rotary kiln, and the thickness or internal state of the refractory material layer is monitored based on the obtained temperature detection signal.

特開平１１−２１８３２０号公報JP 11-218320 A 特開２００１−４２８３号公報JP 2001-4283 A

上記したように、電気式溶融炉において水冷構造を備えない炉底耐火材は侵食、崩壊し易く、炉底耐火物が侵食や崩壊で消失すると炉内の溶融物が炉底ケーシングまで到達し、溶融物が漏れ出す状況に発展しかねない。
そこで、特許文献２に記載されるように温度計により測定した温度に基づいて炉耐火物の損耗状態を監視する方法があるが、これは温度測定の精度に問題があった。 As described above, the bottom refractory material that does not have a water cooling structure in an electric melting furnace is easily eroded and collapsed. It can develop into a situation where the melt leaks.
Therefore, as described in Patent Document 2, there is a method of monitoring the worn state of the furnace refractory based on the temperature measured by the thermometer, but this has a problem in accuracy of temperature measurement.

炉体の温度測定は、特許文献１や特許文献２に記載される熱電対を用いた方法や、放射温度計を用いる方法が一般に用いられている。
しかし、熱電対を耐火材に埋めこむ場合、腐食や熱により断線してしまうという問題があった。また、熱電対によりケーシング表面温度を計測する場合は、耐火材の断熱性のために計測温度の変化が小さく、また図１１に示すように、スラグ温度など運転条件の変動による影響が定常運転時でも±２０℃程度存在し、精度のよい温度計測は困難であった。
一方、放射温度計を用いる場合は、表面放射率が計測面の状況で大きく変化するため正確な値が把握できず、また計測面内に放射率分布が発生することから、温度の絶対値評価が難しいという問題があった。 For the temperature measurement of the furnace body, a method using a thermocouple described in Patent Document 1 or Patent Document 2 or a method using a radiation thermometer is generally used.
However, when a thermocouple is embedded in a refractory material, there has been a problem of disconnection due to corrosion or heat. Also, when measuring the casing surface temperature with a thermocouple, the change in the measured temperature is small due to the heat insulation of the refractory material, and as shown in FIG. However, there was about ± 20 ° C., and accurate temperature measurement was difficult.
On the other hand, when using a radiation thermometer, the surface emissivity varies greatly depending on the measurement surface condition, so accurate values cannot be obtained, and an emissivity distribution is generated within the measurement surface. There was a problem that was difficult.

このように従来の技術では、運転条件の変動や計測誤差を考慮すると計測温度の絶対値評価では、炉底耐火物の異常を検知できなかった。
従って、本発明は上記従来技術の問題点に鑑み、炉底の絶対温度を正確に検出することが困難な場合であっても精度良く炉底異常を検知することができる溶融炉の炉底監視方法及び装置を提供することを目的とする。 As described above, in the conventional technology, in consideration of fluctuations in operating conditions and measurement errors, the absolute value evaluation of the measured temperature cannot detect the abnormality of the furnace bottom refractory.
Therefore, in view of the above-mentioned problems of the prior art, the present invention is capable of detecting the bottom of a melting furnace with high accuracy even when it is difficult to accurately detect the absolute temperature of the bottom of the furnace. It is an object to provide a method and apparatus.

そこで、本発明はかかる課題を解決するために、内部に耐火材が配設され、その外側を鋼板製ケーシングにより覆われた炉底部を有する電気式溶融炉における炉底耐火材の異常を検知する溶融炉の炉底監視方法において、
前記溶融炉における耐火材侵食量とケーシング温度変化量の相関関係からケーシング温度の最大許容変化量を予め設定しておき、
前記ケーシングの温度を計測し、該ケーシングの時系列的な計測温度から温度変化量を算出し、該温度変化量と前記最大許容変化量とを比較し、前記温度変化量が前記最大許容変化量を超える場合に炉底耐火材の異常と判定することを特徴とする。 Therefore, in order to solve such a problem, the present invention detects an abnormality in the furnace bottom refractory material in an electric melting furnace having a furnace bottom portion in which a refractory material is disposed and covered outside by a steel plate casing. In the bottom monitoring method of the melting furnace,
From the correlation between the refractory material erosion amount and the casing temperature change amount in the melting furnace, preset the maximum allowable change amount of the casing temperature,
The temperature of the casing is measured, a temperature change amount is calculated from a time-series measured temperature of the casing, the temperature change amount is compared with the maximum allowable change amount, and the temperature change amount is the maximum allowable change amount. It is determined that an abnormality of the furnace bottom refractory material is exceeded.

本発明は、ケーシングの相対温度変化に基づいて炉底異常を検知する構成としたため、ケーシング計測温度の絶対値精度とは関係なく精度の高い検出結果を得ることができる。また本発明によれば、炉底耐火材の侵食状況とその位置まで把握することができ、異常が検出された場合に炉の緊急停止により溶融物とケーシングの直接接触を事前に防止でき、ケーシングの溶損、損傷による溶融物の漏れ出しトラブルを防止できる。
尚、定常運転時でもスラグ温度は変動しており、ケーシング温度は±２０℃程度の変動を示すが、計測温度の時間平均処理をすることにより耐火材侵食による正確な温度上昇を検知できる。 Since the present invention is configured to detect the furnace bottom abnormality based on the relative temperature change of the casing, a highly accurate detection result can be obtained regardless of the absolute value accuracy of the casing measurement temperature. Further, according to the present invention, the erosion status of the furnace bottom refractory material and its position can be grasped, and when an abnormality is detected, direct contact between the melt and the casing can be prevented beforehand by an emergency stop of the furnace. It is possible to prevent the leakage of molten material due to melting and damage.
Note that the slag temperature fluctuates even during steady operation, and the casing temperature varies by about ± 20 ° C. However, an accurate temperature rise due to refractory material erosion can be detected by performing time-average processing of the measured temperature.

また、前記溶融炉内のスラグ温度を検出し、該検出したスラグ温度とスラグ温度が予め設定された標準運転時におけるスラグ温度との差分を算出し、スラグ温度変化量とケーシング温度変化量の相関関係から前記差分に相当する温度補正値を前記ケーシングの計測温度に加えることを特徴とする。
上記したように、定常運転時にもスラグ温度は変動し、これに伴いケーシング温度も変動する。従って、温度変化量を検出する間にスラグ温度が大幅に変動すると正確な温度変化量を求められない場合がある。従って本発明では、スラグ温度のケーシング温度への影響を予め熱伝導解析で予測しておき、これに基づいてケーシングの計測温度を補正することで、標準運転時に相当する計測温度を得ることができ、運転状況の変動に関わらず精度のよい異常検出が可能となる。
尚、スラグ温度の検出は、炉内のスラグ温度を直接計測する方法や、入出熱量のバランスから算出する方法などが挙げられ、何れの方法を用いてもよい。 Further, the slag temperature in the melting furnace is detected, the difference between the detected slag temperature and the slag temperature in the standard operation in which the slag temperature is set in advance is calculated, and the correlation between the slag temperature change amount and the casing temperature change amount is calculated. From the relationship, a temperature correction value corresponding to the difference is added to the measured temperature of the casing.
As described above, the slag temperature varies even during steady operation, and the casing temperature also varies accordingly. Therefore, if the slag temperature fluctuates significantly while detecting the temperature change amount, an accurate temperature change amount may not be obtained. Therefore, in the present invention, the influence of the slag temperature on the casing temperature is predicted in advance by heat conduction analysis, and the measured temperature corresponding to the standard operation can be obtained by correcting the measured temperature of the casing based on this. Therefore, it is possible to detect an abnormality with high accuracy regardless of fluctuations in driving conditions.
The detection of the slag temperature includes a method of directly measuring the slag temperature in the furnace, a method of calculating from the balance of heat input and output, and any method may be used.

さらに、内部に耐火材が配設され、その外側をケーシングにより覆われた炉底部を有する電気式溶融炉における炉底耐火材の異常を検知する溶融炉の炉底監視方法において、
前記ケーシングの材料強度低下温度である基準温度を予め設定しておき、
前記ケーシングの温度分布を検出し、該温度分布のうち前記基準温度を超える領域を高温領域とし、該高温領域の半径若しくは長径が、ケーシングにかかる荷重、ケーシング厚さ及びケーシング温度から設定された最大許容半径若しくは最大許容長径を超える場合に炉底耐火材の異常と判定することを特徴とする。 Furthermore, in the furnace bottom monitoring method of the melting furnace for detecting an abnormality of the furnace bottom refractory material in an electric melting furnace having a furnace bottom portion disposed inside and covered with a casing on the outside thereof,
A reference temperature that is a material strength lowering temperature of the casing is set in advance,
The temperature distribution of the casing is detected, a region exceeding the reference temperature in the temperature distribution is defined as a high temperature region, and a radius or a major axis of the high temperature region is a maximum set from a load applied to the casing, a casing thickness, and a casing temperature. When the allowable radius or the maximum allowable major axis is exceeded, it is determined that the furnace bottom refractory material is abnormal.

炉底耐火物が消失して溶融物がケーシングに近づくと、ケーシング温度が上昇する。さらにその高温領域が広範囲の場合、溶融物がケーシングに到達する前にケーシング強度の低下と発生応力によってケーシングが損傷するという問題があった。また、高温化することで材料の許容応力も低下するので、炉体耐火物や溶融物の重量によってケーシングに亀裂が発生する。
そこで、本発明にように、溶融炉ごとにケーシングにかかる荷重、ケーシング厚さ及びケーシング温度から求めた最大許容半径若しくは最大許容長径を予め設定し、運転時における高温領域の半径若しくは長径との比較からケーシング強度の合否判定を行うことによって、局所的な高温部位のみでなく、広範囲に亘って温度上昇がおこり材料強度が低下した場合においても的確に異常を検知することができる。 As the furnace refractory disappears and the melt approaches the casing, the casing temperature rises. Furthermore, when the high temperature region is wide, there is a problem that the casing is damaged due to a decrease in casing strength and generated stress before the melt reaches the casing. Further, since the allowable stress of the material is reduced by increasing the temperature, cracks are generated in the casing due to the weight of the furnace refractory or the melt.
Therefore, as in the present invention, the maximum allowable radius or maximum allowable major axis obtained from the load applied to the casing, casing thickness and casing temperature for each melting furnace is set in advance, and compared with the radius or major axis of the high temperature region during operation. By determining whether or not the casing strength is acceptable, it is possible to accurately detect an abnormality even when the temperature rises over a wide range as well as the local high-temperature region and the material strength decreases.

また、内部に耐火材が配設され、その外側を鋼板製ケーシングにより覆われた炉底部を有する電気式溶融炉における炉底耐火材の異常を検知する溶融炉の炉底監視装置において、
前記ケーシングの温度を計測する温度計と、該計測した温度に基づいて炉底の異常を検知する制御装置と、を備え、
前記温度計が、前記ケーシングの時系列的な温度変化を検出する手段であり、
前記制御装置は、耐火材侵食量とケーシング温度変化量の相関関係に基づき予め設定されたケーシング温度の最大許容変化量が格納された格納手段と、前記温度計により得られた温度変化量と前記最大許容変化量とを比較し、前記温度変化量が前記最大許容変化量を超える場合に炉底耐火材の異常と判定する比較判定手段と、を備えることを特徴とする。 In addition, in the furnace bottom monitoring device for the melting furnace, which detects an abnormality of the furnace bottom refractory material in an electric melting furnace having a furnace bottom portion in which a refractory material is disposed inside and covered with a steel plate casing,
A thermometer that measures the temperature of the casing, and a control device that detects an abnormality in the furnace bottom based on the measured temperature,
The thermometer is means for detecting a time-series temperature change of the casing;
The control device includes a storage unit that stores a preset maximum allowable change amount of the casing temperature based on a correlation between the refractory material erosion amount and the casing temperature change amount, the temperature change amount obtained by the thermometer, and the Comparing and determining means for comparing with a maximum allowable change amount, and determining that the bottom refractory material is abnormal when the temperature change amount exceeds the maximum allowable change amount.

さらに、前記溶融炉内のスラグ温度を検出するスラグ温度検出手段を備え、
前記制御装置は、前記スラグ温度検出手段により検出したスラグ温度と、スラグ温度が予め設定された標準運転時におけるスラグ温度との差分を算出し、スラグ温度変化量とケーシング温度変化量の相関関係から前記差分に相当する温度補正値を前記ケーシングの計測温度に加える補正手段を備えることを特徴とする。 Furthermore, slag temperature detecting means for detecting the slag temperature in the melting furnace is provided,
The control device calculates the difference between the slag temperature detected by the slag temperature detecting means and the slag temperature at the time of standard operation in which the slag temperature is preset, and from the correlation between the slag temperature change amount and the casing temperature change amount. A correction means for adding a temperature correction value corresponding to the difference to the measured temperature of the casing is provided.

さらにまた、内部に耐火材が配設され、その外側をケーシングにより覆われた炉底部を有する電気式溶融炉における炉底耐火材の異常を検知する溶融炉の炉底監視装置において、
前記ケーシングの温度を計測する温度計と、該計測した温度に基づいて炉底の異常を検知する制御装置と、を備え、
前記温度計が、前記炉底ケーシングの温度分布を検出する手段であり、
前記制御装置は、ケーシングの材料強度低下温度である基準温度が設定された格納手段と、前記温度計により得られた温度分布のうち前記基準温度を超える高温領域を検出する高温領域検出手段と、該検出した高温領域の半径若しくは長径が、ケーシングにかかる荷重、ケーシング厚さ及びケーシング温度から設定された最大許容半径若しくは最大許容長径を超える場合に炉底耐火材の異常と判定する比較判定手段と、を備えることを特徴とする。 Furthermore, in the furnace bottom monitoring device of the melting furnace, which detects an abnormality of the furnace bottom refractory material in an electric melting furnace having a furnace bottom portion in which a refractory material is disposed inside and covered with a casing on the outside,
A thermometer that measures the temperature of the casing, and a control device that detects an abnormality in the furnace bottom based on the measured temperature,
The thermometer is means for detecting the temperature distribution of the furnace bottom casing;
The control device includes a storage unit in which a reference temperature that is a material strength lowering temperature of the casing is set, a high temperature region detection unit that detects a high temperature region exceeding the reference temperature among the temperature distribution obtained by the thermometer, A comparison judgment means for judging that the furnace bottom refractory material is abnormal when the detected radius or major axis of the high temperature region exceeds the maximum allowable radius or the maximum allowable major axis set from the load applied to the casing, the casing thickness and the casing temperature. It is characterized by providing.

以上記載のごとく本発明によれば、ケーシングの相対温度変化に基づいて炉底異常を検知する構成としたため、ケーシング計測温度の絶対値精度とは関係なく精度の高い検出結果を得ることができる。
また、スラグ温度のケーシング温度への影響を予め熱伝導解析で予測しておき、これに基づいてケーシングの計測温度を補正することで、標準運転時に相当する計測温度を得ることができ、運転状況の変動に関わらず精度のよい異常検出が可能となる。
また、本発明によれば、ケーシングの高温領域と最大許容半径若しくは最大許容長径との比較からケーシング強度の合否判定を行うようにしたため、局所的な高温部位のみでなく、広範囲に亘って温度上昇がおこり材料強度が低下した場合においても的確に異常を検知することができる。 As described above, according to the present invention, since the furnace bottom abnormality is detected based on the relative temperature change of the casing, a highly accurate detection result can be obtained regardless of the absolute value accuracy of the casing measurement temperature.
In addition, the influence of the slag temperature on the casing temperature is predicted in advance by heat conduction analysis, and the measured temperature corresponding to the standard operation can be obtained by correcting the measured temperature of the casing based on this. Therefore, it is possible to detect an abnormality with high accuracy regardless of the fluctuation of.
In addition, according to the present invention, since the pass / fail determination of the casing strength is performed based on the comparison between the high temperature region of the casing and the maximum allowable radius or the maximum allowable long diameter, the temperature rises not only in the local high temperature region but also in a wide range. Even when the material strength decreases, the abnormality can be accurately detected.

以下、図面を参照して本発明の好適な実施例を例示的に詳しく説明する。但しこの実施例に記載されている構成部品の寸法、材質、形状、その相対的配置等は特に特定的な記載がない限りは、この発明の範囲をそれに限定する趣旨ではなく、単なる説明例に過ぎない。
本実施例では炉底監視対象である溶融炉として、一例としてプラズマ式溶融炉につき説明するが、被処理物を溶融処理する溶融炉であれば特にこれに限定されるものではない。
図１〜図６は実施例１を説明するための図で、図７〜図９は実施例２を説明するための図である。
図１及び図２は本実施例１に係る炉底監視装置を備えた溶融炉の側断面図、図３は本実施例１に係る炉底監視方法のフロー図、図４は炉底耐火レンガの侵食量とケーシング温度の相関関係を示すグラフ、図５は最大許容温度差を説明する図、図６は計測温度の補正方法を説明する図である。
図７は本実施例２に係る炉底監視装置を備えた溶融炉の概略図、図８は最大許容半径を説明する図、図９は本実施例２に係る炉底監視方法のフロー図である。 Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the components described in this embodiment are not intended to limit the scope of the present invention unless otherwise specified, but are merely illustrative examples. Not too much.
In the present embodiment, a plasma melting furnace will be described as an example of a melting furnace that is a furnace bottom monitoring target. However, the present invention is not particularly limited as long as it is a melting furnace that melts a workpiece.
1 to 6 are diagrams for explaining the first embodiment, and FIGS. 7 to 9 are diagrams for explaining the second embodiment.
1 and 2 are side sectional views of a melting furnace equipped with a furnace bottom monitoring device according to the first embodiment, FIG. 3 is a flowchart of the furnace bottom monitoring method according to the first embodiment, and FIG. 4 is a furnace bottom refractory brick. 5 is a graph showing the correlation between the amount of erosion and the casing temperature, FIG. 5 is a diagram for explaining the maximum allowable temperature difference, and FIG. 6 is a diagram for explaining a method for correcting the measured temperature.
FIG. 7 is a schematic view of a melting furnace provided with a furnace bottom monitoring device according to the second embodiment, FIG. 8 is a diagram for explaining the maximum allowable radius, and FIG. 9 is a flowchart of the furnace bottom monitoring method according to the second embodiment. is there.

まず、図１を参照して、本実施例に係る炉底監視装置が設置されるプラズマ式溶融炉１０につき説明する。プラズマ式溶融炉１０は、炉本体１４の炉蓋から主電極１１が垂下され、これに対向して炉底から炉底電極１２が挿設されている。プラズマ式灰溶融炉１０では、これらの電極間に直流電源１３により直流電流を通流して炉内にプラズマアーク２４を発生させる。投入ホッパ２１より投入された被処理物は、炉壁に設けられた被処理物投入口２０より炉内に投下され、プラズマアーク熱及び前記電極間を流れる電流のジュール熱により溶融処理され、溶融スラグ２２として炉底に溜まる。また溶融スラグ２２の下部には比重差により溶融メタル２３が形成されている。溶融後は、適宜出滓口２５より排出される。
炉本体１４の側壁及び蓋部の内側は不定形耐火材１５で形成され、炉底には、侵食に強いアーチ状の耐火レンガ１８が内側に配設され、その下に耐火レンガ１９が配設される。これらの耐火物の外表面は鋼板製のケーシング１６で被覆されている。 First, a plasma melting furnace 10 in which a furnace bottom monitoring apparatus according to this embodiment is installed will be described with reference to FIG. In the plasma melting furnace 10, a main electrode 11 is suspended from a furnace lid of a furnace body 14, and a furnace bottom electrode 12 is inserted from the furnace bottom to face the main electrode 11. In the plasma ash melting furnace 10, a direct current is passed between these electrodes by a direct current power source 13 to generate a plasma arc 24 in the furnace. An object to be processed input from the input hopper 21 is dropped into the furnace through an object input port 20 provided on the furnace wall, and is melted and processed by plasma arc heat and Joule heat of current flowing between the electrodes. The slag 22 accumulates at the furnace bottom. In addition, a molten metal 23 is formed in the lower portion of the molten slag 22 due to a difference in specific gravity. After melting, it is discharged from the tap 25 as appropriate.
The inner side of the side wall and the lid portion of the furnace body 14 is formed of an irregular refractory material 15, and an arcuate refractory brick 18 that is resistant to erosion is disposed on the inside of the furnace bottom, and the refractory brick 19 is disposed below the refractory brick. Is done. The outer surface of these refractories is covered with a casing 16 made of steel plate.

本実施例では、炉底ケーシング１７の温度を計測するための温度計を一または複数備えている。温度計の種類は限定されないが、熱電対３０若しくはサーモグラフィ装置３１などが挙げられる。
熱電対３０を用いる場合は、炉底ケーシング表面に設置するか、若しくは耐火物に浅く埋設してあり、図１に示すように炉底の略全面に亘って温度測定できるように複数設けられている。複数の熱電対３０を設置し、温度ｔ１〜ｔ６までの炉底温度分布を計測できるようにすることが好ましい。
サーモグラフィ装置３１を用いる場合は、図２に示すように、炉底の略全面が視野範囲となるように、一又は数台設けられる。尚、サーモグラフィ装置３０は、測定対象から放出される放射エネルギ量を非接触で検出して該放射エネルギ量から測定対象の温度を求める周知の装置である。 In this embodiment, one or more thermometers for measuring the temperature of the furnace bottom casing 17 are provided. Although the kind of thermometer is not limited, the thermocouple 30 or the thermography apparatus 31 etc. are mentioned.
When the thermocouple 30 is used, it is installed on the surface of the furnace bottom casing or buried shallowly in the refractory, and a plurality of the thermocouples 30 are provided so that the temperature can be measured over almost the entire surface of the furnace bottom as shown in FIG. Yes. It is preferable to install a plurality of thermocouples 30 so that the temperature distribution at the bottom of the furnace from temperatures t 1 to t 6 can be measured.
When using the thermography apparatus 31, as shown in FIG. 2, one or several sets are provided so that the substantially whole surface of a furnace bottom may become a visual field range. The thermography device 30 is a well-known device that detects the amount of radiant energy emitted from the measurement object in a non-contact manner and determines the temperature of the measurement object from the amount of radiant energy.

熱電対３０若しくはサーモグラフィ装置３１は制御装置４０に接続され、計測した温度信号は該制御装置４０に送られる。制御装置４０には、炉底ケーシング１７の温度変化量と炉底耐火物の侵食量の相関関係に基づいて設定された炉底ケーシング温度の最大許容変化量が格納された格納手段と、熱電対３０により計測された温度変化量と前記最大許容変化量とを比較して、温度変化量が最大許容変化量を超える場合に炉底耐火材の異常と判定する比較判定手段と、該比較判定手段により炉底耐火材の異常と判定された場合に異常警報を発する出力手段と、を備える。   The thermocouple 30 or the thermography device 31 is connected to the control device 40, and the measured temperature signal is sent to the control device 40. The control device 40 includes storage means for storing a maximum allowable change amount of the furnace bottom casing temperature set based on a correlation between the temperature change amount of the furnace bottom casing 17 and the erosion amount of the furnace bottom refractory, and a thermocouple. A comparison determination unit that compares the temperature change amount measured by 30 with the maximum allowable change amount and determines that the bottom refractory material is abnormal when the temperature change amount exceeds the maximum allowable change amount; and the comparison determination unit Output means for issuing an abnormality alarm when it is determined that the furnace refractory material is abnormal.

炉底ケーシング１７の温度変化量と炉底耐火物の侵食量の相関関係は、熱伝導解析により導き出す方法、実測値から求める方法などがある。この相関関係を図４に示す。同図に示すように、炉底ケーシング温度がΔＴ℃上昇すると耐火レンガの侵食量はｄｍｍであることが導かれる。例えば、アーチ状レンガ１８が消失し、その下の耐火レンガ１９が１００ｍｍ侵食すると、炉底ケーシング温度は約６０℃上昇する。従って、熱電対３０により時系列的な温度を計測し、この測定温度の変化量が６０℃となったら耐火レンガ１９の侵食量が１００ｍｍであることがわかる。耐火レンガ１９の許容侵食量は装置によって設定されており、これに対応する温度変化量が許容温度変化量となる。
一方、定常運転時でもスラグ温度は変動しており、炉底ケーシング温度は±２０℃程度の変動を示すが、計測データの時間平均処理をすれば耐火材侵食による温度上昇を検知できる。 The correlation between the temperature change amount of the furnace bottom casing 17 and the erosion amount of the furnace bottom refractory includes a method derived from heat conduction analysis, a method obtained from an actual measurement value, and the like. This correlation is shown in FIG. As shown in the figure, when the furnace bottom casing temperature rises by ΔT ° C., it is derived that the erosion amount of the refractory brick is dmm. For example, when the arcuate brick 18 disappears and the refractory brick 19 below erodes 100 mm, the furnace bottom casing temperature rises by about 60 ° C. Therefore, the time-series temperature is measured by the thermocouple 30, and when the amount of change in the measured temperature reaches 60 ° C., it can be seen that the erosion amount of the refractory brick 19 is 100 mm. The allowable erosion amount of the refractory brick 19 is set by the apparatus, and the temperature change amount corresponding to this is the allowable temperature change amount.
On the other hand, the slag temperature fluctuates even during steady operation, and the furnace bottom casing temperature varies by about ± 20 ° C. However, if the measurement data is time-averaged, a temperature rise due to refractory material erosion can be detected.

図５（ａ）に、例として正常運転時と異常運転時におけるケーシング温度を夫々示す。正常運転時には、炉の中心より出滓口側に僅かにずれた位置が最も温度が高く、出滓口及び灰投入口側は低くなっている。これに対して、異常運転時はいずれの位置においても正常運転時よりも温度が高く、且つ灰投入口側に最も高い温度が現れている。（ｂ）は炉底ケーシング位置と温度変化量の関係を示すグラフで、（ａ）における異常運転時と正常運転時の温度差分を示したものである。これによれば、最大許容温度差を超える部分が灰投入口側に現れていることがわかる。このように、現運転における温度変化量を求めることで、異常運転か否かを容易に判定でき、且つその位置も特定することができる。   FIG. 5A shows casing temperatures during normal operation and abnormal operation, respectively. During normal operation, the temperature is highest at a position slightly shifted from the center of the furnace to the tap outlet side, and the tap outlet and the ash inlet side are low. In contrast, during abnormal operation, the temperature is higher at any position than during normal operation, and the highest temperature appears on the ash inlet side. (B) is a graph showing the relationship between the furnace bottom casing position and the temperature change amount, and shows the temperature difference between the abnormal operation and the normal operation in (a). According to this, it can be seen that a portion exceeding the maximum allowable temperature difference appears on the ash inlet side. In this way, by obtaining the temperature change amount in the current operation, it is possible to easily determine whether or not the operation is abnormal, and it is also possible to specify the position.

また、前記制御装置４０は、運転条件の変動による温度計測値の誤差を補正する補正手段を備えることが好ましい。
炉底耐火材１８、１９は侵食していなくても、運転スラグ温度が高いと炉底ケーシング温度が上昇することがある。図６に示すように、標準運転時のスラグ温度と現運転時のスラグ温度が異なると、これに伴い炉底ケーシング温度もΔＴだけ異なる。
補正手段は、現運転におけるスラグ温度を検出し、該検出したスラグ温度と予め設定された標準運転時におけるスラグ温度との差分を算出し、スラグ温度変化量とケーシング温度変化量の相関関係から前記差分に相当する温度補正値をケーシングの計測温度に加える補正を行う手段である。スラグ温度の検出は、炉内のスラグ温度を直接計測する方法や、入出熱量のバランスから算出する方法などが挙げられる。
例えば、炉内のスラグ温度のケーシング温度への影響を予め熱伝導解析により予測しておき、ケーシング温度の計測値を修正することで、標準運転時（例えば１６００℃運転）のケーシング温度分布と比較することができる。
このように、スラグ温度が炉底ケーシング温度へ与える影響の予測結果から、現運転と標準運転との炉底ケーシング温度の変化分を計算し、これを用いて現運転でのケーシング計測温度を修正し、標準運転相当の炉底ケーシング温度を求めることで補正を行うことにより、運転条件に変動があってもこの変動を排除した精度の高い測定が可能となる。 Moreover, it is preferable that the said control apparatus 40 is provided with the correction | amendment means which correct | amends the error of the temperature measurement value by the fluctuation | variation of an operating condition.
Even if the bottom refractory materials 18 and 19 are not eroded, the bottom casing temperature may rise if the operating slag temperature is high. As shown in FIG. 6, if the slag temperature during the standard operation and the slag temperature during the current operation are different, the furnace bottom casing temperature is also different by ΔT.
The correction means detects the slag temperature in the current operation, calculates a difference between the detected slag temperature and a slag temperature in the standard operation set in advance, and calculates the difference from the correlation between the slag temperature change amount and the casing temperature change amount. It is a means for performing correction to add a temperature correction value corresponding to the difference to the measured temperature of the casing. Examples of the detection of the slag temperature include a method of directly measuring the slag temperature in the furnace, a method of calculating from the balance of heat input and output, and the like.
For example, the effect of the slag temperature in the furnace on the casing temperature is predicted in advance by heat conduction analysis, and the measured value of the casing temperature is corrected to compare with the casing temperature distribution during standard operation (eg, 1600 ° C. operation). can do.
In this way, from the prediction result of the effect of the slag temperature on the bottom casing temperature, the change in the bottom casing temperature between the current operation and the standard operation is calculated, and this is used to correct the casing measurement temperature in the current operation. In addition, by performing correction by obtaining the furnace bottom casing temperature equivalent to the standard operation, it is possible to perform highly accurate measurement that eliminates the fluctuation even if the operating condition fluctuates.

次に、図３を参照して本実施例１に係る炉底監視方法のフローにつき説明する。
まず、温度変化量−侵食量の相関関係から温度変化の最大許容変化量を求め、制御装置４０に予め設定しておく（Ｓ１）。プラズマ式溶融炉１０の通常運転を開始したら、温度計により連続的に若しくは間欠的に炉底ケーシング温度を計測する（Ｓ２）。
このとき、炉内のスラグ温度を計測し、計測したスラグ温度に基づいて現在の運転状態を判定する（Ｓ３）。これは、炉内スラグ温度が標準運転の範囲内であるかを否かを判断し（Ｓ４）、標準運転でない場合には、上記した補正手段により計測温度の補正を行う（Ｓ５）。 Next, the flow of the furnace bottom monitoring method according to the first embodiment will be described with reference to FIG.
First, the maximum allowable change amount of the temperature change is obtained from the correlation between the temperature change amount and the erosion amount, and is preset in the control device 40 (S1). When the normal operation of the plasma melting furnace 10 is started, the furnace bottom casing temperature is measured continuously or intermittently with a thermometer (S2).
At this time, the slag temperature in the furnace is measured, and the current operation state is determined based on the measured slag temperature (S3). In this case, it is determined whether or not the in-furnace slag temperature is within the range of the standard operation (S4), and if it is not the standard operation, the measured temperature is corrected by the correction means described above (S5).

運転状態が標準運転である場合は、計測温度よりケーシング温度の時系列的な変化量を算出する（Ｓ６）。標準以外の運転の場合も補正後に同様の処理を行う。そして、この算出した温度変化量と、予め設定しておいた最大許容変化量とを比較する（Ｓ７）。温度変化量が最大許容変化量を超えた場合は（Ｓ８）、制御装置４０により炉底の耐火物に異常ありと判定し（Ｓ９）、温度変化量が最大許容変化量以下である場合は異常なしと判定する（Ｓ１０）。尚、異常ありと判定された場合は、炉の運転を停止し、耐火レンガ１９の補修・交換を行う。   When the operation state is the standard operation, the time-series change amount of the casing temperature is calculated from the measured temperature (S6). In the case of non-standard operation, the same processing is performed after correction. Then, the calculated temperature change amount is compared with a preset maximum allowable change amount (S7). When the temperature change amount exceeds the maximum allowable change amount (S8), the controller 40 determines that there is an abnormality in the refractory at the bottom of the furnace (S9), and when the temperature change amount is less than or equal to the maximum allowable change amount, it is abnormal It is determined that there is none (S10). If it is determined that there is an abnormality, the operation of the furnace is stopped, and the refractory brick 19 is repaired or replaced.

このように、本実施例によれば、炉底ケーシング１７の計測温度の絶対値の精度が低くても、相対温度変化は比較的精度良く計測できるので、予め求めた最大許容温度差と計測温度変化値を比較することで、炉底耐火材の侵食状況とその位置（領域）を把握でき、炉の緊急停止により、溶融物とケーシングの直接接触を事前に防止でき、ケーシングの溶損、損傷による溶融物の漏れ出しトラブルを防止できる。   As described above, according to the present embodiment, even if the accuracy of the absolute value of the measured temperature of the furnace bottom casing 17 is low, the relative temperature change can be measured with relatively high accuracy. By comparing the change values, the erosion status of the bottom refractory material and its position (region) can be grasped, and the emergency stop of the furnace can prevent direct contact between the melt and the casing in advance, and the casing can be damaged or damaged. This prevents the leakage of molten material caused by

図７を参照して本実施例２に係る炉底監視装置及び方法につき説明する。
炉底耐火物１８、１９が消失し溶融物が炉底ケーシング１７に近づくと、炉底ケーシング温度は上昇するが、この高温領域が広範囲の場合、溶融物が炉底ケーシング１７に到達する前に、ケーシングの材料強度の低下と発生応力によって、炉底ケーシング１７が損傷する。本実施例は、このように広範囲に亘る炉底耐火物の異常を検知するものである。 A furnace bottom monitoring apparatus and method according to the second embodiment will be described with reference to FIG.
When the bottom refractory 18, 19 disappears and the melt approaches the bottom casing 17, the bottom casing temperature rises, but when this high temperature region is wide, before the melt reaches the bottom casing 17. The furnace bottom casing 17 is damaged due to the lowering of the material strength of the casing and the generated stress. In this embodiment, abnormalities in the furnace bottom refractories over a wide range are detected.

本実施例２の詳細な装置構成は、図１及び図２に示すプラズマ式溶融炉１０と同様である。尚、本実施例２において、上記した実施例１と同一の構成についてはその詳細な説明を省略する。
図７（ａ）に示されるように、電気式溶融炉（プラズマ式溶融炉）１０は、温度計（熱電対）３０と、制御装置４０と、を備える。
温度計として熱電対３０を用いる場合は、炉底１７の温度分布を測定できるように熱電対３０を炉底全面に亘って複数個所設置する。好ましくは、熱電対３０を出滓口２５へ向けたスラグ流れ方向に沿って設置するとよい。サーモグラフィ装置３１を用いる場合は、炉底の略全面が視野範囲となるように一又は複数台設置する。図７（ｂ）は、炉底ケーシングの高温領域３５を示す。 The detailed apparatus configuration of the second embodiment is the same as that of the plasma melting furnace 10 shown in FIGS. In the second embodiment, detailed description of the same configuration as that of the first embodiment will be omitted.
As shown in FIG. 7A, the electric melting furnace (plasma melting furnace) 10 includes a thermometer (thermocouple) 30 and a control device 40.
When the thermocouple 30 is used as a thermometer, a plurality of thermocouples 30 are installed over the entire furnace bottom so that the temperature distribution of the furnace bottom 17 can be measured. Preferably, the thermocouple 30 may be installed along the slag flow direction toward the tap outlet 25. When the thermography device 31 is used, one or a plurality of devices are installed so that substantially the entire surface of the furnace bottom is within the visual field range. FIG. 7B shows a high temperature region 35 of the furnace bottom casing.

制御装置４０は、高温領域の閾値となる基準温度Ｔと、荷重ｐ、ケーシング厚さｄ、ケーシング温度ｔから求めたケーシングの高温強度限界を示す最大許容半径ｒmax（若しくは長径Ｒmax）とが格納された格納手段と、炉底温度分布内の基準温度Ｔを超える高温領域３５を検出する高温領域検出手段と、高温領域３５の半径ｒと最大許容半径ｒmaxとを比較し、半径ｒが最大許容半径ｒmaxを超える場合に異常と判定する比較判定手段と、異常時に警報を発する出力手段と、を備える。
この制御装置４０では、熱電対３０若しくはサーモグラフィ装置３１で測定した温度分布に基づいて、各計測点での温度が基準温度Ｔを超えた領域を高温領域と定義し、その半径ｒ若しくは長辺Ｒが予めケーシングの高温強度限界から予測された最大値ｒmax若しくはＲmaxを超えたかどうかで、ケーシングの強度合否を判断し、異常を検知する装置である。 The control device 40 has a reference temperature T serving as a threshold value in the high temperature region, and a maximum allowable radius r max (or major axis R max ) indicating a high temperature strength limit of the casing obtained from the load p, the casing thickness d, and the casing temperature t. The stored storing means, the high temperature region detecting means for detecting the high temperature region 35 exceeding the reference temperature T in the furnace bottom temperature distribution, the radius r of the high temperature region 35 and the maximum allowable radius r max are compared, and the radius r is Comparing / determining means for determining an abnormality when the maximum allowable radius r max is exceeded, and an output means for issuing an alarm when abnormal.
In this control device 40, based on the temperature distribution measured by the thermocouple 30 or the thermography device 31, a region where the temperature at each measurement point exceeds the reference temperature T is defined as a high temperature region, and its radius r or long side R Is a device that judges whether the strength of the casing is acceptable or not by detecting whether or not the maximum value r max or R max predicted in advance from the high temperature strength limit of the casing is exceeded.

炉底ケーシング１７の温度分布に現れる高温領域３５は、正円状、長円状、若しくは変形円状となることが多い。
高温領域３５が正円状の場合は、炉底ケーシング１７に発生する最大応力は円の半径の２乗に比例する。また、高温化することで材料の許容応力も低下するので、炉内の耐火物、溶融物の重量によって炉底ケーシング１７に亀裂が発生する。
そこで、溶融炉ごとに荷重ｐ、ケーシング厚さｄ、ケーシング温度ｔから求めた最大許容半径ｒmaxを予め設定し、運転時の高温領域半径ｒとの比較からケーシング強度の合否判定を行い、異常を検知する。 The high temperature region 35 appearing in the temperature distribution of the furnace bottom casing 17 is often a perfect circle, an ellipse, or a deformed circle.
When the high temperature region 35 is a perfect circle, the maximum stress generated in the furnace bottom casing 17 is proportional to the square of the radius of the circle. Further, since the allowable stress of the material is reduced by increasing the temperature, cracks occur in the furnace bottom casing 17 due to the weight of the refractory and melt in the furnace.
Therefore, the maximum allowable radius r max obtained from the load p, casing thickness d, and casing temperature t is preset for each melting furnace, and the pass / fail judgment of the casing strength is made by comparing with the high temperature region radius r during operation. Is detected.

図８（ａ）に、例として炉底ケーシング１７に高温領域３５が現れた場合のケーシング位置に対応した温度を示す。出滓口よりに基準温度Ｔを超える温度領域が出現しており、これを高温領域３５と定義する。図８（ｂ）に、ケーシング温度ｔに対する最大許容半径ｒmaxを示す。最大許容半径ｒmaxは、ケーシング温度ｔが高くなる程小さくなる。即ち、ケーシング温度ｔが高いほど材料強度が低下し、小さい荷重でケーシングが損傷するため耐えうる半径が小さくなることを表す。本実施例では、基準温度Ｔ以上の温度範囲から、温度ｔに対応する最大許容半径ｒmaxを一段階若しくは複数段階設けておき、計測された炉底熱分布がこの最大許容半径ｒmaxを超えたら異常ありと判定する。 FIG. 8A shows the temperature corresponding to the casing position when the high temperature region 35 appears in the furnace bottom casing 17 as an example. A temperature region exceeding the reference temperature T appears from the tap and is defined as a high temperature region 35. FIG. 8B shows the maximum allowable radius r max with respect to the casing temperature t. The maximum allowable radius r max decreases as the casing temperature t increases. That is, the higher the casing temperature t, the lower the material strength and the smaller the radius that can be tolerated because the casing is damaged by a small load. In this embodiment, the maximum allowable radius r max corresponding to the temperature t is provided in one or more stages from the temperature range equal to or higher than the reference temperature T, and the measured furnace bottom heat distribution exceeds the maximum allowable radius r max . If so, it is determined that there is an abnormality.

また、高温領域３５の面積から異常検知することもできる。これは、炉底ケーシング１７の温度分布から基準温度Ｔを超える高温領域３５の面積を算出し、該面積を等価円に換算してこの等価円の半径ｒを求める。半径ｒから上記した正円状高温領域の場合と同様に異常検知を行う。
一方、高温領域３５が長円状若しくは変形円状である場合には、その長径Ｒから異常検知を行う。これは、溶融炉ごとに荷重Ｐ、炉底ケーシング厚さｔ、炉底ケーシング温度Ｔから求めた最大許容長径Ｒmaxを予め設定しておき、運転時の高温領域長辺Ｒとの比較からケーシング強度の合否判定を行い、異常を検知する。 Further, an abnormality can be detected from the area of the high temperature region 35. This calculates the area of the high temperature region 35 exceeding the reference temperature T from the temperature distribution of the furnace bottom casing 17, and converts the area into an equivalent circle to obtain the radius r of the equivalent circle. Abnormality detection is performed from the radius r in the same manner as in the above-described perfect circular high temperature region.
On the other hand, when the high temperature region 35 is in the shape of an ellipse or a deformed circle, an abnormality is detected from the major axis R. This is because the maximum allowable long diameter R max obtained from the load P, the furnace bottom casing thickness t, and the furnace bottom casing temperature T is preset for each melting furnace, and the casing is compared with the high temperature region long side R during operation. The strength is accepted or rejected, and an abnormality is detected.

次に、図３を参照して本実施例２に係る炉底監視方法のフローにつき説明する。
まず、炉底ケーシング１７における高温領域３５の閾値となる基準温度Ｔと、荷重ｐ、ケーシング厚さｄ、ケーシング温度ｔから求めた最大許容半径ｒmax（若しくは長径Ｒmax）とを制御装置４０に予め設定しておく（Ｓ１１）。プラズマ式溶融炉１０の通常運転を開始したら、熱電対３１により炉底ケーシング１７の温度を計測し（Ｓ１２）、ここから炉底ケーシング１７の温度分布を算出する（Ｓ１３）。次いで、この温度分布から基準温度Ｔに基づき高温領域３５の有無を判定する（Ｓ１４）。基準温度Ｔより高い温度を示す高温領域３５が存在するか否かの判定において（Ｓ１５）、存在しない場合には通常運転を続行する。高温領域３５が存在する場合にはその半径ｒと最大許容半径ｒmaxとを比較し（Ｓ１６）、半径ｒが最大許容半径ｒmaxを超えるか否かを判断する（Ｓ１７）。半径ｒが最大許容半径ｒmaxを超える場合には、炉底耐火物が広範囲に亘って侵食され炉底ケーシング１７の強度が低下して危険な状態であるため異常ありと判定し（Ｓ１８）、警報手段により警報を発する。尚、異常ありと判定された場合は、炉の運転を停止し、炉底耐火物１８、１９の補修・交換を行う。一方、高温領域の半径ｒが最大許容半径ｒmaxを超えていない場合には、異常なしと判定する（Ｓ１９）。 Next, the flow of the furnace bottom monitoring method according to the second embodiment will be described with reference to FIG.
First, a reference temperature T serving as a threshold value for the high temperature region 35 in the furnace bottom casing 17, a maximum allowable radius r max (or a major axis R max ) obtained from the load p, the casing thickness d, and the casing temperature t are set in the control device 40. It is set in advance (S11). When the normal operation of the plasma melting furnace 10 is started, the temperature of the furnace bottom casing 17 is measured by the thermocouple 31 (S12), and the temperature distribution of the furnace bottom casing 17 is calculated therefrom (S13). Next, the presence / absence of the high temperature region 35 is determined from the temperature distribution based on the reference temperature T (S14). In determining whether or not the high temperature region 35 showing a temperature higher than the reference temperature T exists (S15), if it does not exist, normal operation is continued. When the high temperature region 35 exists, the radius r is compared with the maximum allowable radius r max (S16), and it is determined whether the radius r exceeds the maximum allowable radius r max (S17). When the radius r exceeds the maximum allowable radius r max , the furnace bottom refractory is eroded over a wide range, the strength of the furnace bottom casing 17 is lowered, and it is determined that there is an abnormality (S18), An alarm is issued by an alarm means. If it is determined that there is an abnormality, the operation of the furnace is stopped and the furnace bottom refractories 18 and 19 are repaired or replaced. On the other hand, when the radius r of the high temperature region does not exceed the maximum allowable radius rmax , it is determined that there is no abnormality (S19).

本実施例によれば、温度計により計測された炉底温度が、実施例１のように炉底ケーシング１７を直接損傷する温度まで上昇していなくても、高温領域が広範囲に亘って出現した場合に、溶融炉内容物の自重などによって炉底ケーシング１７が損傷することを防止できる。   According to this example, even if the furnace bottom temperature measured by the thermometer does not rise to a temperature at which the furnace bottom casing 17 is directly damaged as in Example 1, a high temperature region appears over a wide range. In this case, it is possible to prevent the furnace bottom casing 17 from being damaged by the dead weight of the contents of the melting furnace.

尚、本実施例では、実施例１と実施例２を組み合わせた構成としてもよい。例えば、図３に示したフローを第１ステップとし、図９に示したフローを第２ステップとし、第１ステップで異常なしと判定された場合に、第２ステップを行うようにする。これにより、より高精度の異常検出を行うことが可能となり、安定運転を保障することができる。   In addition, in a present Example, it is good also as a structure which combined Example 1 and Example 2. FIG. For example, the flow shown in FIG. 3 is the first step, the flow shown in FIG. 9 is the second step, and the second step is performed when it is determined that there is no abnormality in the first step. As a result, it is possible to detect an abnormality with higher accuracy and to ensure stable operation.

本発明は、炉底の絶対温度を高精度で検出できない場合であっても炉底耐火物の異常を的確に検出することができるため、プラズマ式溶融炉を始めとして、電気抵抗式溶融炉、バーナ式溶融炉、旋回式溶融炉、反射式溶融炉等の何れの溶融炉にも適用可能である。   Since the present invention can accurately detect the abnormality of the furnace bottom refractory even when the absolute temperature of the furnace bottom cannot be detected with high accuracy, an electric resistance melting furnace, including a plasma melting furnace, The present invention can be applied to any melting furnace such as a burner type melting furnace, a swirling type melting furnace, a reflection type melting furnace or the like.

本実施例１に係る炉底監視装置を備えた溶融炉の側断面図である。1 is a side sectional view of a melting furnace equipped with a furnace bottom monitoring device according to a first embodiment. 図１の応用例を示す炉底監視装置を備えた溶融炉の側断面図である。It is a sectional side view of the melting furnace provided with the furnace bottom monitoring apparatus which shows the application example of FIG. 本実施例１に係る炉底監視方法のフロー図である。1 is a flowchart of a furnace bottom monitoring method according to the first embodiment. 炉底耐火レンガの侵食量とケーシング温度の相関関係を示すグラフである。It is a graph which shows the correlation of the amount of erosion of a furnace bottom refractory brick, and casing temperature. 最大許容温度差を説明する図で、（ａ）は異常時と正常時における温度分布の比較を示すグラフ、（ｂ）は炉底ケーシング位置と温度変化量の関係を示すグラフである。It is a figure explaining the maximum allowable temperature difference, (a) is a graph which shows the comparison of the temperature distribution in the time of abnormality, and (b) is a graph which shows the relationship between a furnace bottom casing position and temperature variation. 計測温度の補正方法を説明する図である。It is a figure explaining the correction method of measured temperature. 本実施例２に係る炉底監視装置を備えた溶融炉の概略図で、（ａ）は側断面図、（ｂ）は底面図である。It is the schematic of the melting furnace provided with the furnace bottom monitoring apparatus which concerns on the present Example 2, (a) is a sectional side view, (b) is a bottom view. 最大許容半径を説明する図で、（ａ）は炉底ケーシング位置と温度の関係を示すグラフ、（ｂ）はケーシング温度と許容半径を示すグラフである。It is a figure explaining the maximum allowable radius, (a) is a graph which shows the relationship between a furnace bottom casing position and temperature, (b) is a graph which shows casing temperature and an allowable radius. 本実施例２に係る炉底監視方法のフロー図である。It is a flowchart of the furnace bottom monitoring method which concerns on the present Example 2. 従来の溶融炉の断面を示す全体構成図である。It is a whole block diagram which shows the cross section of the conventional melting furnace. 従来の温度計により測定した炉底温度の測定値である。It is the measured value of the furnace bottom temperature measured with the conventional thermometer.

符号の説明Explanation of symbols

１０ プラズマ式溶融炉
１１ 主電極
１２ 炉底電極
１３ 直流電源
１４ 炉本体
１７ 炉底ケーシング
１８ アーチ状レンガ
１９ 耐火レンガ
２１ 投入ホッパ
２２ 溶融スラグ（スラグ層）
２３ 溶融メタル（メタル層）
２５ スラグ出滓口
３０ 熱電対
３１ サーモグラフィ装置
４０ 制御装置 DESCRIPTION OF SYMBOLS 10 Plasma type melting furnace 11 Main electrode 12 Furnace bottom electrode 13 DC power supply 14 Furnace main body 17 Furnace bottom casing 18 Arched brick 19 Refractory brick 21 Input hopper 22 Molten slag (slag layer)
23 Molten metal (metal layer)
25 Slag outlet 30 Thermocouple 31 Thermography device 40 Control device

Claims (6)

内側に耐火材が配設され、その外側を鋼板製ケーシングにより覆われた炉底部を有する電気式溶融炉における炉底耐火材の異常を検知する溶融炉の炉底監視方法において、
前記溶融炉における耐火材侵食量とケーシング温度変化量の相関関係からケーシング温度の最大許容変化量を予め設定しておき、
前記ケーシングの温度を計測し、該ケーシングの時系列的な計測温度から温度変化量を算出し、該温度変化量と前記最大許容変化量とを比較し、前記温度変化量が前記最大許容変化量を超える場合に炉底耐火材の異常と判定することを特徴とする溶融炉の炉底監視方法。 In the furnace bottom monitoring method of the melting furnace, in which an abnormality of the furnace bottom refractory material is detected in the electric melting furnace having the furnace bottom part which is provided with a furnace bottom part which is covered with a steel plate casing on the outside thereof,
From the correlation between the refractory material erosion amount and the casing temperature change amount in the melting furnace, preset the maximum allowable change amount of the casing temperature,
The temperature of the casing is measured, a temperature change amount is calculated from a time-series measured temperature of the casing, the temperature change amount is compared with the maximum allowable change amount, and the temperature change amount is the maximum allowable change amount. A furnace bottom monitoring method for a melting furnace, characterized by determining that the furnace refractory material is abnormal when the temperature exceeds. 前記溶融炉内のスラグ温度を検出し、該検出したスラグ温度とスラグ温度が予め設定された標準運転時におけるスラグ温度との差分を算出し、スラグ温度変化量とケーシング温度変化量の相関関係から前記差分に相当する温度補正値を前記ケーシングの計測温度に加えることを特徴とする請求項１記載の溶融炉の炉底監視方法。 Detecting the slag temperature in the melting furnace, calculating the difference between the detected slag temperature and the slag temperature at the time of standard operation in which the slag temperature is preset, and from the correlation between the slag temperature change amount and the casing temperature change amount The method according to claim 1, wherein a temperature correction value corresponding to the difference is added to the measured temperature of the casing. 内部に耐火材が配設され、その外側を鋼板製ケーシングにより覆われた炉底部を有する電気式溶融炉における炉底耐火材の異常を検知する溶融炉の炉底監視方法において、
前記ケーシングの材料強度低下温度である基準温度を予め設定しておき、
前記ケーシングの温度分布を検出し、該温度分布のうち前記基準温度を超える領域を高温領域とし、該高温領域の半径若しくは長径が、ケーシングにかかる荷重、ケーシング厚さ及びケーシング温度から設定された最大許容半径若しくは最大許容長径を超える場合に炉底耐火材の異常と判定することを特徴とする溶融炉の炉底監視方法。 In the furnace bottom monitoring method of the melting furnace, in which an abnormality of the furnace bottom refractory material is detected in the electric melting furnace having a furnace bottom portion that is disposed inside and covered with a steel plate casing on the outside,
A reference temperature that is a material strength lowering temperature of the casing is set in advance,
The temperature distribution of the casing is detected, a region exceeding the reference temperature in the temperature distribution is defined as a high temperature region, and a radius or a major axis of the high temperature region is a maximum set from a load applied to the casing, a casing thickness, and a casing temperature. A furnace bottom monitoring method for a melting furnace, characterized in that when the allowable radius or the maximum allowable major axis is exceeded, it is determined that the furnace bottom refractory is abnormal. 内部に耐火材が配設され、その外側をケーシングにより覆われた炉底部を有する電気式溶融炉における炉底耐火材の異常を検知する溶融炉の炉底監視装置において、
前記ケーシングの温度を計測する温度計と、該計測した温度に基づいて炉底の異常を検知する制御装置と、を備え、
前記温度計が、前記ケーシングの時系列的な温度変化を検出する手段であり、
前記制御装置は、耐火材侵食量とケーシング温度変化量の相関関係に基づき予め設定されたケーシング温度の最大許容変化量が格納された格納手段と、前記温度計により得られた温度変化量と前記最大許容変化量とを比較し、前記温度変化量が前記最大許容変化量を超える場合に炉底耐火材の異常と判定する比較判定手段と、を備えることを特徴とする溶融炉の炉底監視装置。 In the furnace bottom monitoring device of the melting furnace, which detects an abnormality of the furnace bottom refractory material in an electric melting furnace having a furnace bottom portion in which a refractory material is disposed and covered outside by a casing,
A thermometer that measures the temperature of the casing, and a control device that detects an abnormality in the furnace bottom based on the measured temperature,
The thermometer is means for detecting a time-series temperature change of the casing;
The control device includes a storage unit that stores a preset maximum allowable change amount of the casing temperature based on a correlation between the refractory material erosion amount and the casing temperature change amount, the temperature change amount obtained by the thermometer, and the A furnace bottom monitor for a melting furnace, comprising: a comparison judgment means for comparing with a maximum allowable change amount, and determining that the bottom refractory material is abnormal when the temperature change amount exceeds the maximum allowable change amount. apparatus. 前記溶融炉内のスラグ温度を検出するスラグ温度検出手段を備え、
前記制御装置は、前記スラグ温度検出手段により検出したスラグ温度と、スラグ温度が予め設定された標準運転時におけるスラグ温度との差分を算出し、スラグ温度変化量とケーシング温度変化量の相関関係から前記差分に相当する温度補正値を前記ケーシングの計測温度に加える補正手段を備えることを特徴とする請求項４記載の溶融炉の炉底監視装置。 Comprising slag temperature detecting means for detecting the slag temperature in the melting furnace,
The control device calculates the difference between the slag temperature detected by the slag temperature detecting means and the slag temperature at the time of standard operation in which the slag temperature is preset, and from the correlation between the slag temperature change amount and the casing temperature change amount. The furnace bottom monitoring device for a melting furnace according to claim 4 , further comprising correction means for adding a temperature correction value corresponding to the difference to the measured temperature of the casing. 内部に耐火材が配設され、その外側をケーシングにより覆われた炉底部を有する電気式溶融炉における炉底耐火材の異常を検知する溶融炉の炉底監視装置において、
前記ケーシングの温度を計測する温度計と、該計測した温度に基づいて炉底の異常を検知する制御装置と、を備え、
前記温度計が、前記炉底ケーシングの温度分布を検出する手段であり、
前記制御装置は、ケーシングの材料強度低下温度である基準温度が設定された格納手段と、前記温度計により得られた温度分布のうち前記基準温度を超える高温領域を検出する高温領域検出手段と、該検出した高温領域の半径若しくは長径が、ケーシングにかかる荷重、ケーシング厚さ及びケーシング温度から設定された最大許容半径若しくは最大許容長径を超える場合に炉底耐火材の異常と判定する比較判定手段と、を備えることを特徴とする溶融炉の炉底監視装置。 In the furnace bottom monitoring device of the melting furnace, which detects an abnormality of the furnace bottom refractory material in an electric melting furnace having a furnace bottom portion in which a refractory material is disposed and covered outside by a casing,
A thermometer that measures the temperature of the casing, and a control device that detects an abnormality in the furnace bottom based on the measured temperature,
The thermometer is means for detecting the temperature distribution of the furnace bottom casing;
The control device includes a storage unit in which a reference temperature that is a material strength lowering temperature of the casing is set, a high temperature region detection unit that detects a high temperature region exceeding the reference temperature among the temperature distribution obtained by the thermometer, A comparison judgment means for judging that the furnace bottom refractory material is abnormal when the detected radius or major axis of the high temperature region exceeds the maximum allowable radius or the maximum allowable major axis set from the load applied to the casing, the casing thickness and the casing temperature. A furnace bottom monitoring device for a melting furnace.
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