JP2001272019A - Method for operation of electric melting furnace - Google Patents
Method for operation of electric melting furnaceInfo
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- JP2001272019A JP2001272019A JP2000088652A JP2000088652A JP2001272019A JP 2001272019 A JP2001272019 A JP 2001272019A JP 2000088652 A JP2000088652 A JP 2000088652A JP 2000088652 A JP2000088652 A JP 2000088652A JP 2001272019 A JP2001272019 A JP 2001272019A
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- Prior art keywords
- melting furnace
- furnace
- electric
- grounding
- ground
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Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は産業廃棄物、ごみ焼
却炉からの焼却残渣や焼却飛灰、下水汚泥等の溶融処理
技術に関するものであり、電気溶融炉の構成材である炉
材の電気絶縁性能の劣化を自動的に高精度で検出するこ
とにより、電気溶融炉の溶融処理能率の低下やエネルギ
ー損失の増大、機器の損傷、人身事故等を生ずることな
しに、高能率で安全に被溶融物を溶融処理できるように
した電気溶融炉の運転方法に関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technology for melting industrial waste, incineration residue from a refuse incinerator, fly ash, sewage sludge, etc. Automatically detects the deterioration of insulation performance with high accuracy, enabling high-efficiency and safe melting without reducing the melting processing efficiency of the electric melting furnace, increasing energy loss, damage to equipment, personal injury, etc. The present invention relates to an operation method of an electric melting furnace capable of melting a material.
【０００２】[0002]
【従来の技術】ごみ焼却炉から排出される焼却残滓や飛
灰等は、溶融処理することにより容積を約１／３に減ら
す事ができると共に、重金属等の有害物質の溶出を防止
することができる。又、溶融スラグは道路用材やコンク
リート骨材として再利用できるうえ、減容により最終埋
立処分場の延命を図ることができる。2. Description of the Related Art The volume of incineration residues and fly ash discharged from a refuse incinerator can be reduced to about 1/3 by melting, and the elution of harmful substances such as heavy metals can be prevented. it can. In addition, the molten slag can be reused as road material or concrete aggregate, and the life of the final landfill can be extended by reducing the volume.
【０００３】前記焼却残滓の溶融処理には、アーク溶融
炉やプラズマ溶融炉等の電気エネルギーを用いる溶融方
法と、表面溶融炉や旋回溶融炉等の燃料の燃焼エネルギ
ーを用いる溶融方法とがあり、ごみ焼却施設に発電設備
が併置されている場合には、前者の電気エネルギーを用
いる方法が多く利用されている。[0003] The melting treatment of the incineration residue includes a melting method using electric energy such as an arc melting furnace or a plasma melting furnace, and a melting method using fuel combustion energy such as a surface melting furnace or a rotating melting furnace. When a power generation facility is installed in a refuse incineration facility, the former method using electric energy is often used.
【０００４】図５は従前のごみ焼却施設に併置した直流
アーク放電黒鉛電極式プラズマ溶融炉の一例を示すもの
であり、図に於いて１は灰コンテナ、２は供給装置、３
は溶融炉本体、４は黒鉛主電極、５は黒鉛スタート電
極、６は炉底電極、７は炉底冷却ファン、８は直流電源
装置、９は不活性ガス供給装置、１０は溶融スラグ流出
口、１１はタップホール、１２は燃焼室、１３は燃焼空
気ファン、１４は排ガス冷却ファン、１５はバグフィル
タ、１６は誘引通風機、１７は煙突、１８は溶融飛灰コ
ンベア、１９は飛灰だめ、２０はスラグ水冷槽、２１は
スラグ搬出コンベア、２２はスラグだめ、２３はスラグ
冷却水の冷却装置である。FIG. 5 shows an example of a DC arc discharge graphite electrode type plasma melting furnace juxtaposed in a conventional refuse incineration facility. In FIG.
Is a melting furnace body, 4 is a graphite main electrode, 5 is a graphite start electrode, 6 is a furnace bottom electrode, 7 is a furnace bottom cooling fan, 8 is a DC power supply, 9 is an inert gas supply device, and 10 is a molten slag outlet. , 11 is a tap hole, 12 is a combustion chamber, 13 is a combustion air fan, 14 is an exhaust gas cooling fan, 15 is a bag filter, 16 is an induction draft fan, 17 is a chimney, 18 is a molten fly ash conveyor, and 19 is fly ash sump. , 20 is a slag water cooling tank, 21 is a slag carry-out conveyor, 22 is slag storage, and 23 is a slag cooling water cooling device.
【０００５】コンテナ１内の焼却残渣や飛灰等（被溶融
物）Ａは供給装置２により溶融炉本体３内へ連続的に供
給される。溶融炉本体３には、炉頂部より略垂直に挿入
した黒鉛主電極４（−極）と、炉底に設置した炉底電極
６（＋極）とが設けられており、両電極４、６間に印加
した直流電源装置８（容量約６００〜１０００ＫＷ／Ｔ
・被溶融物）の電圧によりプラズマアーク電流が流れ、
これによって被溶融物Ａが１３００℃〜１６００℃に加
熱されることにより、順次溶融スラグＢとなる。尚、被
溶融物Ａは導電性が低いため、溶融炉の始動時にはスタ
ート電極（＋極）５を溶融炉本体３内へ挿入し、これと
黒鉛主電極４間へ通電することにより被溶融物Ａの溶融
を待つ。そして、被溶融物が溶融してその導電性が上昇
すると、スタート電極５を炉底電極６側へ切り換える。The incineration residue, fly ash, etc. (melted material) A in the container 1 is continuously supplied into the melting furnace main body 3 by the supply device 2. The melting furnace main body 3 is provided with a graphite main electrode 4 (-pole) inserted substantially vertically from the furnace top and a furnace bottom electrode 6 (+ pole) installed on the furnace bottom. DC power supply 8 (capacity of about 600 to 1000 KW / T
・ Plasma arc current flows due to the voltage of
Thereby, the material to be melted A is heated to 1300 ° C. to 1600 ° C., whereby the molten slag B is sequentially formed. Since the material to be melted A has low conductivity, the start electrode (+ electrode) 5 is inserted into the body 3 of the melting furnace at the start of the melting furnace, and a current is applied between this and the graphite main electrode 4 so that the material to be melted is heated. Wait for A to melt. When the material to be melted is melted and its conductivity increases, the start electrode 5 is switched to the furnace bottom electrode 6 side.
【０００６】溶融炉本体３の内部は、溶融スラグＢや黒
鉛主電極４等の酸化を防止するため還元性雰囲気に保持
されており、不活性ガス供給装置９から不活性ガスＣ
が、中空筒状に形成した黒鉛主電極４及びスタート電極
５の中空孔を通して、溶融炉本体３内へ連続的に供給さ
れている。尚、不活性ガスＣを黒鉛主電極４やスタート
電極５の中空孔を通して溶融炉本体３内へ供給するの
は、プラズマ放電領域に不活性ガスＣを充満させた方
が、プラズマアークの発生や安定性等の所謂プラズマ放
電性が良好になる、及び黒鉛主電極４やスタート電極
５の消耗がより少なくなるからである。The inside of the melting furnace main body 3 is maintained in a reducing atmosphere in order to prevent oxidation of the molten slag B and the graphite main electrode 4 and the like.
Is continuously supplied into the melting furnace main body 3 through the hollow holes of the graphite main electrode 4 and the start electrode 5 formed in a hollow cylindrical shape. The inert gas C is supplied into the melting furnace main body 3 through the hollow holes of the graphite main electrode 4 and the start electrode 5 when the plasma discharge region is filled with the inert gas C because of the occurrence of plasma arc or the like. This is because the so-called plasma discharge property such as stability is improved, and the consumption of the graphite main electrode 4 and the start electrode 5 is further reduced.
【０００７】溶融炉本体３の炉底は炉底冷却ファン７か
らの冷風により空冷され、これによって炉底電極６近傍
の過度な温度上昇が防止されている。また、溶融炉本体
３そのものは高温に耐える耐火材及びそれを覆う断熱材
等により構成されており、必要に応じて断熱材の外部に
水冷ジャケット（図示省略）が設けられる。The furnace bottom of the melting furnace body 3 is air-cooled by cool air from a furnace cooling fan 7, thereby preventing an excessive rise in temperature near the furnace bottom electrode 6. The melting furnace body 3 itself is made of a refractory material that can withstand high temperatures and a heat insulating material covering the same, and a water cooling jacket (not shown) is provided outside the heat insulating material as necessary.
【０００８】被溶融物Ａの溶融によって、その内部に存
在した揮発成分や発生した一酸化炭素等はガス体Ｄとな
る。また、鉄等の金属類やガラス、砂等の不燃性成分
は、プラズマアーク放電の発生熱により溶融点（１２０
０〜１２５０℃）を越えた約１３００℃〜１６００℃に
まで加熱され、流動性を有する液体状の溶融スラグＢと
なる。[0008] By the melting of the material to be melted A, the volatile components present therein and the generated carbon monoxide and the like become gaseous substances D. In addition, metals such as iron, and incombustible components such as glass and sand are melted (120 ° C) by heat generated by plasma arc discharge.
(0 to 1250 ° C.) to about 1300 ° C. to 1600 ° C. to form a liquid molten slag B having fluidity.
【０００９】溶融炉本体３に形成された溶融スラグＢは
溶融スラグ流出口１０より連続的に溢出し、水を満した
スラグ冷却槽２０内へ落下して水砕スラグとなり、スラ
グ搬出コンベア２１によってスラグだめ２２へ排出され
る。また、溶融炉を停止する際には、溶融炉本体３内の
溶融スラグＢが冷却、固化してしまうのを防止するた
め、タップホール１１から湯抜きを行い、溶融炉本体３
内を空状態にする。The molten slag B formed in the melting furnace main body 3 continuously overflows from the molten slag outlet 10 and falls into a slag cooling tank 20 filled with water to become granulated slag. It is discharged to the slag reservoir 22. Further, when the melting furnace is stopped, a molten metal is drained from the tap hole 11 to prevent the molten slag B in the melting furnace main body 3 from cooling and solidifying.
Empty inside.
【００１０】前記ガス体Ｄは溶融スラグ流出口１０の上
部より燃焼室１２に入り、ここで燃焼空気ファン１３か
ら燃焼用空気が送入されることにより、内部の未燃分が
完全燃焼される。また、燃焼排ガスは排ガス冷却ファン
１４からの冷空気によって冷却されたあと、バグフィル
タ１５を経て誘引通風機１６により煙突１７へ排出され
る。更に、バグフィルタ１５で捕捉された溶融飛灰Ｅ
は、溶融飛灰コンベア１８により飛灰だめ１９へ送られ
る。The gaseous substance D enters the combustion chamber 12 from above the molten slag outlet 10 and the combustion air is fed from the combustion air fan 13 so that the unburned portion inside is completely burned. . Further, the combustion exhaust gas is cooled by the cool air from the exhaust gas cooling fan 14, and then discharged through the bag filter 15 to the chimney 17 by the induction ventilator 16. Further, the molten fly ash E captured by the bag filter 15
Is sent to the fly ash sump 19 by the molten fly ash conveyor 18.
【００１１】而して、プラズマ溶融炉等の電気溶融炉で
は、従前から電気絶縁性に優れた炉材３ａを用いて溶融
炉本体３が形成されており、また、炉材３ａの外表部は
保護材である炉体鉄皮３ｂにより覆われている。炉材３
ａを電気絶縁性の高いものとすることにより、炉材３ａ
内に於ける電気エネルギー損失を抑制できるだけでな
く、サイドアークや機器の損傷、人身事故等の発生も防
止できるからである。[0011] In an electric melting furnace such as a plasma melting furnace, the melting furnace main body 3 is formed by using a furnace material 3a having excellent electric insulation properties. It is covered with a furnace shell 3b as a protection material. Furnace material 3
a is made of a material having high electrical insulation,
This is because not only the electric energy loss in the inside can be suppressed, but also the occurrence of side arcs, damage to equipment, personal injury, and the like can be prevented.
【００１２】ところが、前記炉材３ａの電気絶縁特性
は、所謂経時変化によって劣化するだけでなく、溶融ス
ラグＢや溶融メタルの隙間への侵入、電極シール部への
低融点金属等の付着によってもその性能が劣化する。ま
た、万一炉材３ａの電気絶縁性能が劣化すると、必然的
に黒鉛主電極４と炉底電極６間以外に通電路が形成され
ることになり、前述したように電気エネルギーの損失が
生ずるだけでなく、サイドアークや機器の損傷、人身事
故等の危険性が増加する。However, the electrical insulation properties of the furnace material 3a are not only deteriorated by so-called aging, but also by the penetration of the molten slag B and the molten metal into the gaps and the adhesion of the low melting point metal to the electrode seal portion. Its performance deteriorates. Also, if the electrical insulation performance of the furnace material 3a deteriorates, an energization path is necessarily formed between the graphite main electrode 4 and the furnace bottom electrode 6 and electric energy loss occurs as described above. In addition, the risk of side arcs, equipment damage, personal injury, etc. increases.
【００１３】そのため、従前の電気溶融炉では、図２に
示すように、電源トランス８ａの２次側の接地の他に溶
融炉本体３の前記鉄皮３ｂを接地することにより、鉄皮
３ｂに内接する炉材３ａの絶縁劣化等によりこれ等に電
流が流れても、溶融炉本体３の電位が大地と同電位とな
る。尚、前記鉄皮３ｂの接地は、専用の接地電極と接地
線Ｌ1 を用いて各溶融炉本体３毎に行なうようにしてい
る。For this reason, in the conventional electric melting furnace, as shown in FIG. 2, the iron shell 3b of the melting furnace main body 3 is grounded in addition to the grounding of the secondary side of the power transformer 8a. Even if current flows through the insulated furnace material 3a due to insulation deterioration or the like, the potential of the melting furnace main body 3 becomes the same potential as the ground. The ground of the furnace shell 3b is to perform for each melting furnace main body 3 with the ground line L 1 and the ground electrode dedicated.
【００１４】また、従前の電気溶融炉に於いては、前記
鉄皮３ｂの接地だけでなく、図３に示すように黒鉛主電
極４及び炉底電極６と溶融炉本体３との間に耐熱性の絶
縁体２４を介在させ、各電極４、６と溶融炉本体３間を
電気的に絶縁する構造としたものが存在する。この図３
の構造に於いては、万一炉材３ａの絶縁性能が劣化して
も、絶縁体２４の絶縁性能が良好である限り、ある程度
の安全性は確保されることになる。しかし、低融点金属
等の付着により絶縁体２４の絶縁性能が劣化した場合に
は、前記と同様の支障を生ずることになる。Further, in the conventional electric melting furnace, not only the grounding of the iron shell 3b but also the heat resistance between the graphite main electrode 4 and the bottom electrode 6 and the melting furnace main body 3 as shown in FIG. There is a structure in which the electrodes 4, 6 and the melting furnace body 3 are electrically insulated from each other by interposing a conductive insulator 24. This figure 3
In the structure (1), even if the insulation performance of the furnace material 3a deteriorates, a certain degree of safety can be secured as long as the insulation performance of the insulator 24 is good. However, when the insulating performance of the insulator 24 is deteriorated due to the adhesion of the low melting point metal or the like, the same trouble as described above occurs.
【００１５】図４は、前記図３の電気溶融炉の電気的な
等価回路を示すものである。いま、図３に於いて、溶融
炉本体３内の溶融物が全て溶融スラグＢであり、また、
溶融炉本体３の内径が３５０ｃｍφ、深さが４５ｃｍで
あるとすると、スラグ抵抗Ｒｂは、Ｒｂ＝ρｂ×Ｌ／Ｓ
＝（５０×４５）／（３５０×３５０×π／４）＝５．
８×１０-3（Ω）となる。但し、ρｂはスラグの抵抗率
５０Ω−ｃｍ、Ｌは深さ、Ｓは断面積である。今ここ
で、電源からの供給電流Ｉｓ＝１２．５ｋＡ、溶融炉本
体３内を流れる電流Ｉｅの最大許容値をＩｅ＝１２．５
Ａとすると、必要とする溶融炉本体３の絶縁抵抗Ｒｅは
Ｒｅ＝Ｒｂ×（Ｉｓ−Ｉｅ）／Ｉｅ≒５．８（Ω）とな
る。FIG. 4 shows an electric equivalent circuit of the electric melting furnace shown in FIG. Now, in FIG. 3, the molten material in the melting furnace main body 3 is all molten slag B,
Assuming that the inner diameter of the melting furnace body 3 is 350 cmφ and the depth is 45 cm, the slag resistance Rb is Rb = ρb × L / S
= (50 × 45) / (350 × 350 × π / 4) = 5.
It becomes 8 × 10 −3 (Ω). Here, ρb is the resistivity of the slag 50Ω-cm, L is the depth, and S is the cross-sectional area. Here, the supply current Is from the power source = 12.5 kA, and the maximum allowable value of the current Ie flowing in the melting furnace main body 3 is Ie = 12.5 kA.
Assuming that A, the required insulation resistance Re of the melting furnace main body 3 is Re = Rb × (Is−Ie) /Ie≒5.8 (Ω).
【００１６】但し、現実の電気溶融炉に於いては、溶融
物が全て溶融スラグＢとなることは殆んどなく、溶融メ
タルがこれに混るため、前記スラグ抵抗Ｒｂは５．８×
１０ -3（Ω）よりも小さくなる。その結果、溶融炉本体
３内を流れる電流Ｉｅもより小さくなる。即ち、溶融炉
本体３が必要とする絶縁抵抗Ｒｅは、安全を考慮して約
１０Ω（約２倍）の抵抗値があれば十分であり、前記絶
縁体２４の抵抗値は、この等価回路に於ける絶縁抵抗値
Ｒｅを勘案して決定される。However, in the actual electric melting furnace,
Most of the material does not become molten slag B,
Slag resistance Rb is 5.8 ×
10 -3(Ω). As a result, the melting furnace body
3 also becomes smaller. That is, the melting furnace
The insulation resistance Re required by the main body 3 is approximately
A resistance value of 10Ω (about 2 times) is sufficient.
The resistance value of the edge 24 is the insulation resistance value in this equivalent circuit.
Determined in consideration of Re.
【００１７】[0017]
【発明が解決しようとする課題】本発明は、従前のこの
種電気溶融炉に於ける上述の如き問題、即ち溶融炉本
体３を形成する炉材３ａの絶縁性能が劣化した場合、炉
材３ａ内に通電路が形成されて電気エネルギーの損失が
増加したり、サイドアークが生じて炉損傷を起すこと、
接地不良の場合には、溶融炉本体３の鉄皮３ｂの電位
と対地電位に差が生じて危険な状態が現出すること、
絶縁体２４を用いる構造の溶融炉本体３の場合、絶縁体
２４の劣化により、前記・と同様の事象が生ずるこ
と等の問題を解決せんとするものであり、電気溶融炉の
運転中炉材３ａの絶縁性能を連続的に監視し、絶縁性能
が設定値以下に低下した場合にはその運転を停止するこ
とにより、電気溶融炉を安全に連続操業することを可能
にした電気溶融炉の運転方法を提供するものである。SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems in the conventional electric melting furnace, namely, when the insulation performance of the furnace material 3a forming the melting furnace body 3 is deteriorated, the furnace material 3a A current path is formed in the inside, increasing the loss of electric energy or causing a side arc to cause furnace damage,
In the case of poor grounding, there is a difference between the potential of the steel shell 3b of the melting furnace body 3 and the ground potential, and a dangerous state appears.
In the case of the melting furnace body 3 having the structure using the insulator 24, the problem that the same event as described above occurs due to the deterioration of the insulator 24 is to be solved. Operation of the electric melting furnace which continuously monitors the insulation performance of 3a and stops the operation when the insulation performance falls below the set value, thereby enabling the safe continuous operation of the electric melting furnace. It provides a method.
【００１８】[0018]
【課題を解決するための手段】溶融炉本体３を形成する
炉材３ａや絶縁体２４の絶縁性能の劣化を検出する方法
については、これ迄にも多くの開発研究が行なわれてい
る。例えば、図２からも明らかなように、鉄皮３ｂの接
地線Ｌ1 に流れる地絡電流Ｉｇを監視することにより、
炉材３ａの絶縁抵抗の変化を知ることが可能である。し
かし、電気溶融炉では、一般に直流電源８と電気溶融炉
間の電路にブスバーが使用されるため、その対地間静電
容量は殆んど零に近い値である。また、直流電源８側の
接地は、整流電源トランス８ａの二次側を接地すること
により行なわれており、直流側の接地は行なわれていな
い。To detect the deterioration of the insulation performance of the furnace material 3a and the insulator 24 forming the melting furnace body 3, many development studies have been made so far. For example, as is apparent from FIG. 2, by monitoring the ground fault current Ig flowing through the ground line L 1 of the furnace shell 3b,
It is possible to know the change in the insulation resistance of the furnace material 3a. However, in an electric melting furnace, since a bus bar is generally used for an electric path between the DC power supply 8 and the electric melting furnace, the capacitance between the electric ground and the ground is almost zero. The DC power supply 8 is grounded by grounding the secondary side of the rectified power transformer 8a, and the DC side is not grounded.
【００１９】そのため、炉材３ａの絶縁劣化時に接地線
Ｌ1 に流れる地絡電流Ｉｇは、現実には数ｍＡ程度の極
く小さな値の電流となる。また、前記対値静電容量も略
零であるため、絶縁劣化が急激に生じた場合でも、これ
による過度地絡電流（充電々流）は殆んど生じない。そ
の結果、従前の電気溶融炉に於いては、地絡電流Ｉｇの
変化から炉材３ａの絶縁劣化を安定して確実にしかも高
精度で検出することが、現実には不可能な状態にある。[0019] Therefore, the ground-fault current Ig flowing through the ground line L 1 at the time of insulation deterioration of furnace material 3a is a current of very small value of about several mA in reality. Further, since the above-mentioned value capacitance is also substantially zero, even if insulation deterioration occurs rapidly, an excessive ground fault current (charging current) hardly occurs due to this. As a result, in the conventional electric melting furnace, it is actually impossible to stably and reliably detect the insulation deterioration of the furnace material 3a with high accuracy from the change in the ground fault current Ig. .
【００２０】また、炉材３ａ内に抵抗率の検出センサー
を分散状に設置し、炉材３ａの抵抗率の変化そのものを
監視することも可能である。しかし、現実には、溶融炉
本体３の温度等の環境条件が厳しいため、設備が大掛か
りになるうえ寿命等の点にも問題があり、電気溶融炉の
運転中に於ける炉材３ａや絶縁体２４の絶縁性能の連続
的な検出は、現時点に於いては不可能な状態にある。It is also possible to dispose a resistivity detection sensor in the furnace material 3a in a distributed manner and to monitor the change in the resistivity of the furnace material 3a itself. However, in reality, the environmental conditions such as the temperature of the melting furnace body 3 are severe, so that the equipment becomes large and there is a problem in the life and the like. Continuous detection of the insulation performance of body 24 is not possible at this time.
【００２１】そこで、本願発明者は、前記地絡電流Ｉｇ
の直流電源側への帰還路を別途に設け、直流電源装置８
や電気溶融炉の主通電回路等に悪影響を与えることなし
に、炉材３ａの絶縁性能の劣化時に於ける地絡電流Ｉｇ
を検出に適した適宜の大きさの電流値とすることを着想
し、各種の回路構成を実稼動の電気溶融炉へ適用するこ
とにより、絶縁劣化の検出試験を積み重ねた。Therefore, the inventor of the present application proposes that the ground fault current Ig
A separate return path for the DC power supply
Ground current Ig when the insulation performance of the furnace material 3a is degraded without adversely affecting the main energizing circuit of the furnace or the electric melting furnace.
In order to obtain a current value of an appropriate magnitude suitable for detection, a test for detecting insulation deterioration was conducted by applying various circuit configurations to an actual operating electric melting furnace.
【００２２】本願発明は、上記炉材３ａの絶縁特性検出
試験の結果に基づいて創作されたものであり、請求項１
の発明は、電気絶縁性の炉材３ａと炉材３ａを覆う鉄皮
３ｂとから成る溶融炉本体３と、当該溶融炉本体３へ電
気エネルギーを供給する直流電源装置８とを備えた電気
溶融炉に於いて、前記溶融炉本体３の鉄皮３ｂを接地す
ると共に、前記直流電源装置８の出力側端子間に接地抵
抗Ｒを介挿してその中間部を接地し、溶融炉本体３の運
転中前記鉄皮３ｂ側の接地線Ｌ1 又は接地抵抗Ｒ側の接
地線Ｌ2 に流れる地絡電流Ｉｇを連続的に検出して、当
該地絡電流Ｉｇの検出値から炉材３ａの電気絶縁性能の
劣化を検知して、電気溶融炉の運転・停止を制御するよ
うにしたことを発明の基本構成とするものである。The present invention has been created based on the results of the insulation property detection test of the furnace material 3a.
The invention relates to an electric melting apparatus comprising: a melting furnace main body 3 including an electrically insulating furnace material 3a and a steel shell 3b covering the furnace material 3a; and a DC power supply device 8 for supplying electric energy to the melting furnace main body 3. In the furnace, the iron shell 3b of the melting furnace main body 3 is grounded, and an intermediate portion thereof is grounded by inserting a grounding resistor R between output terminals of the DC power supply 8 to operate the melting furnace main body 3. the middle ground fault current Ig flowing through the ground line L 2 of the ground lines of the furnace shell 3b side L 1 or the ground resistance R side continuously detected, the electrical insulation of the furnace material 3a from the detected value of the ground fault current Ig The basic configuration of the present invention is to detect the deterioration of the performance and control the operation / stop of the electric melting furnace.
【００２３】請求項２の発明は、請求項１の発明に於い
て、接地抵抗Ｒの大きさを１４００Ω〜１６００Ωとす
ると共に、抵抗値の中央点Ｎを接地するようにしたもの
である。According to a second aspect of the present invention, in the first aspect of the present invention, the magnitude of the ground resistance R is set to 1400 Ω to 1600 Ω, and the center point N of the resistance value is grounded.
【００２４】請求項３の発明は、請求項１の発明に於い
て溶融炉本体３を鉄皮３ｂと各電極４、６との間に絶縁
材２４を配設した構成としたものである。According to a third aspect of the present invention, in the first aspect of the invention, the melting furnace main body 3 has a configuration in which an insulating material 24 is disposed between the iron shell 3b and each of the electrodes 4 and 6.
【００２５】請求項４の発明は、請求項１の発明に於い
て、地絡電流Ｉｇの検出値が定常運転時の検出値の約１
０倍を越えたとき、炉材３ａの電気絶縁性能が劣化した
と判断して電気溶融炉の運転を停止するようにしたもの
である。According to a fourth aspect of the present invention, in the first aspect, the detected value of the ground fault current Ig is about one of the detected value in the steady operation.
When it exceeds 0 times, it is determined that the electric insulation performance of the furnace material 3a has deteriorated, and the operation of the electric melting furnace is stopped.
【００２６】[0026]
【発明の実施の形態】以下、図面に基づいて本発明の実
施形態を説明する。図１は、本発明を実施した電気溶融
炉の電気回路の概要を示すものであり、図１に於いて、
８は直流電源装置、８ａは電源トランス、８ｂは整流
器、３は溶融炉本体、３ａは炉材、３ｂは鉄皮、４は黒
鉛主電極、６は炉底電極、Ｂは溶融スラグ（溶融物）、
Ｒは接地抵抗、Ｉｇは地絡電流、Ｎは抵抗値の中央点で
ある。Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows an outline of an electric circuit of an electric melting furnace embodying the present invention.
8 is a DC power supply, 8a is a power transformer, 8b is a rectifier, 3 is a melting furnace main body, 3a is a furnace material, 3b is a steel shell, 4 is a graphite main electrode, 6 is a furnace bottom electrode, B is a molten slag (melted material). ),
R is a ground resistance, Ig is a ground fault current, and N is a center point of the resistance value.
【００２７】電気溶融炉としては、直流プラズマ溶融炉
が用いられている。しかし、電気溶融炉は直流アーク溶
融炉や直流抵抗溶融炉であってもよいことは勿論であ
る。また、電気溶融炉を形成する溶融炉本体３の鉄皮３
ｂは、従前の電気溶融炉と同様に接地線Ｌ1 により接地
されている。更に、本実施形態では絶縁体２４を各電極
挿入部に用いていないが、図３に示すような絶縁体２４
を用いる型式の電気溶融炉であっても良いことは勿論で
ある。As the electric melting furnace, a DC plasma melting furnace is used. However, it goes without saying that the electric melting furnace may be a DC arc melting furnace or a DC resistance melting furnace. Further, the iron shell 3 of the melting furnace main body 3 forming the electric melting furnace.
b is grounded by a ground line L 1 as with conventional electric melting furnace. Further, in this embodiment, the insulator 24 is not used for each electrode insertion portion, but the insulator 24 as shown in FIG.
It goes without saying that an electric melting furnace of the type using the above may be used.
【００２８】直流電源装置８は、整流器用の電源トラン
ス８ａとサイリスタ型整流器８ｂとから形成されてお
り、電気溶融炉に特有の二次側負荷特性（低電圧・大電
流）に対応できるものであれば、如何なる整流回路型式
のものであってもよい。尚、本実施形態に於いては、三
相純ブリッジ方式の整流電源装置（ＤＣ１００〜４５０
Ｖ、４００〜３８００Ａ）が使用されている。The DC power supply 8 is composed of a power transformer 8a for a rectifier and a thyristor type rectifier 8b, and can cope with a secondary load characteristic (low voltage and large current) peculiar to an electric melting furnace. Any rectifier circuit type may be used. In this embodiment, a three-phase pure bridge rectifying power supply (DC 100 to 450) is used.
V, 400 to 3800 A).
【００２９】整流器８ｂの直流出力端子間には、接地抵
抗Ｒが介挿されており、接地抵抗Ｒの中間点が接地され
ている。具体的には、６００〜８００Ωの抵抗Ｒ1 、Ｒ
2 が２本直列状に接続されており、両者の接続点Ｎ即ち
抵抗値Ｒの中央値に相当する点が接地線Ｌ2 により接地
されている。尚、各接地抵抗Ｒは１２００〜１６００Ω
程度に選定されているが、抵抗値Ｒ 1 、Ｒ2 が小さい場
合には、接地抵抗Ｒに於ける損失が増大し、また逆に、
抵抗値Ｒ1 、Ｒ2 が大き過ぎると、炉材８ａの絶縁性能
の劣化時に於ける地絡電流Ｉｇが小さくなり過ぎてその
検出精度が低下するからである。また、本実施形態では
接地抵抗Ｒの中央値を接地点Ｎとしているが、設置点Ｎ
は必ずしも接地抵抗Ｒの中央値の点に限られるものでは
ない。A grounding resistor is provided between the DC output terminals of the rectifier 8b.
An anti-R is inserted, and the middle point of the ground resistance R is grounded.
ing. Specifically, a resistance R of 600 to 800Ω1, R
TwoAre connected in series, and a connection point N between them, that is,
The point corresponding to the central value of the resistance value R is the ground line L.TwoGround by
Have been. In addition, each ground resistance R is 1200-1600Ω.
The resistance value R 1, RTwoIs small
In this case, the loss in the ground resistance R increases, and conversely,
Resistance value R1, RTwoIs too large, the insulation performance of the furnace material 8a
The ground fault current Ig at the time of deterioration of
This is because the detection accuracy decreases. In this embodiment,
Although the median value of the ground resistance R is the ground point N,
Is not necessarily limited to the center value of the ground resistance R.
Absent.
【００３０】炉材３ａの絶縁性能が劣化したり、絶縁体
２４が設けられている場合にその絶縁性能が劣化する
と、電源からの供給電流Ｉｓの一部が地絡電流Ｉｇと接
地線Ｌ 1 へ流れ込み、地絡電流Ｉｇが増加する。また、
当該地絡電流Ｉｇは、接地線Ｌ 2 及び接地抵抗Ｒ1 を通
して整流器８ｂ側へ還流する。The insulation performance of the furnace material 3a is deteriorated,
When 24 is provided, its insulation performance is deteriorated.
And a part of the supply current Is from the power supply contacts the ground fault current Ig.
Ground line L 1And the ground fault current Ig increases. Also,
The ground fault current Ig is equal to the ground line L. TwoAnd ground resistance R1Through
Then, it is returned to the rectifier 8b side.
【００３１】溶融処理量（２５ｔｏｎ／日、焼却残滓）
の実稼動中の電気溶融炉Ｋを用いた試験によれば、炉材
３ａの絶縁性が良好な場合には、定常運転時に於ける電
源からの供給電流Ｉｓ（主回路のプラズマ電流）が約１
５００Ａのとき、前記地絡電流Ｉｇは約０．２Ａであ
り、またＩｓが約３０００Ａのとき、Ｉｇは約０．４Ａ
であった。従って、本実施形態に於いては、地絡電流Ｉ
ｇが約０．６Ａ以下であれば、炉材３ａに絶縁劣化が起
っていないと判断することができ、地絡電流Ｉｇを連続
的に監視すると共に、その許容最大値を適宜に設定する
ことにより、これによって電気溶融炉の運転を継続する
か或いは運転を停止するかの判断を行なうことができ
る。Melting amount (25 ton / day, incineration residue)
According to the test using the electric melting furnace K during the actual operation of the furnace, when the insulation property of the furnace material 3a is good, the supply current Is (plasma current of the main circuit) from the power supply during the steady operation is about 1
At 500 A, the ground fault current Ig is about 0.2 A, and when Is is about 3000 A, Ig is about 0.4 A.
Met. Therefore, in the present embodiment, the ground fault current I
If g is about 0.6 A or less, it can be determined that insulation deterioration has not occurred in the furnace material 3a, the ground fault current Ig is continuously monitored, and the allowable maximum value is appropriately set. Thereby, it is possible to determine whether to continue the operation of the electric melting furnace or to stop the operation.
【００３２】具体的には、前記地絡電流Ｉｇが約２Ａ
（供給電流Ｉｓが約１５００Ａのとき）若しくは約４Ａ
（供給電流Ｉｓが約３０００Ａのとき）を越えた場合、
即ち定常時の地絡電流Ｉｇの約１０倍の地絡電流Ｉｇを
検出した時点で、炉材３ａの絶縁が劣化したと判断す
る。そして、手動若しくは自動的に電気溶融炉の連続操
業を停止して、炉材３ａの点検、補修或いは取り換えを
行う。このようにして、炉材３ａや絶縁体２４の絶縁劣
化を地絡電流Ｉｇ値の測定によって検知することで、電
気溶融炉の安定な連続運転を確保することができる。
尚、地絡電流Ｉｇの検出は、接地線Ｌ1 及び接地線Ｌ2
の何れか一方で行なわれ、本実施形態に於いては接地抵
抗Ｒ側の接地線Ｌ2 に流れる地絡電流Ｉｇを連続的に自
動検出している。Specifically, the ground fault current Ig is about 2 A
(When the supply current Is is about 1500 A) or about 4 A
(When the supply current Is is about 3000 A)
That is, it is determined that the insulation of the furnace material 3a has deteriorated when a ground fault current Ig that is about 10 times the ground fault current Ig in a steady state is detected. Then, the continuous operation of the electric melting furnace is stopped manually or automatically, and the furnace material 3a is inspected, repaired or replaced. In this way, by detecting the insulation deterioration of the furnace material 3a and the insulator 24 by measuring the ground fault current Ig value, stable continuous operation of the electric melting furnace can be secured.
The detection of the ground fault current Ig is ground line L 1 and the ground line L 2
Any place in one, in the present embodiment is continuously automatically detect ground-fault current Ig flowing through the ground line L 2 of the ground resistance R side.
【００３３】[0033]
【発明の効果】本発明に於いては、電気溶融炉Ｋの直流
電源装置８の出力側に接地抵抗Ｒを介挿してその中間点
を接地することにより、電気溶融炉の鉄皮３ｂを通して
流れ込む地絡電流Ｉｇを前記接地抵抗Ｒを経て直流電源
側へ環流させ、この地絡電流Ｉｇの検出値の大・小から
炉材３ａや電極挿入部の絶縁体２４の絶縁劣化を判断し
て、電気溶融炉の運転を制御するようにしている。その
結果、従前の電気溶融炉の場合に比較して、炉材３ａ等
の絶縁劣化をより簡単に、しかも確実に高精度で検出す
ることができ、電気エネルギーの損失量の増大や機器の
損傷、人身事故等の発生を未然に防止しつつ電気溶融炉
を安全に且つ高能率で連続運転することが可能となる。
本発明は上述の通り優れた実用的効用を奏するものであ
る。According to the present invention, the output side of the DC power supply 8 of the electric melting furnace K is inserted through the grounding resistor R and the intermediate point thereof is grounded, so that the electric current flows through the iron sheath 3b of the electric melting furnace. The ground fault current Ig is circulated to the DC power supply side via the ground resistance R, and the insulation deterioration of the furnace material 3a and the insulator 24 of the electrode insertion part is determined from the magnitude of the detected value of the ground fault current Ig, The operation of the electric melting furnace is controlled. As a result, the insulation deterioration of the furnace material 3a and the like can be detected more easily and reliably with higher accuracy than in the case of the conventional electric melting furnace, and the loss of electric energy can be increased and the equipment can be damaged. In addition, it is possible to safely and efficiently operate the electric melting furnace continuously while preventing the occurrence of personal injury or the like.
The present invention has excellent practical utility as described above.
【図１】本発明を実施した電気溶融炉の電気回路の概要
図である。FIG. 1 is a schematic diagram of an electric circuit of an electric melting furnace embodying the present invention.
【図２】従前の電気溶融炉の電気回路の概要図である。FIG. 2 is a schematic diagram of an electric circuit of a conventional electric melting furnace.
【図３】従前の電気溶融炉の他の電気回路の概要図であ
る。FIG. 3 is a schematic diagram of another electric circuit of the conventional electric melting furnace.
【図４】図３の電気溶融炉の電気的な等価回路図であ
る。FIG. 4 is an electrical equivalent circuit diagram of the electric melting furnace of FIG.
【図５】従前の電気溶融炉の全体系統図である。FIG. 5 is an overall system diagram of a conventional electric melting furnace.
Ａは被溶融物、Ｂは溶融スラグ、Ｒは接地抵抗、Ｎは抵
抗値の中央点、Ｌ1 ・Ｌ2 は接地線、Ｉｇは地絡電流、
３は溶融炉本体、３ａは炉材、３ｂは鉄皮、４は黒鉛主
電極、５は黒鉛スタート電極、６は炉底電極、８は直流
電源装置、８ａは電源トランス、８ｂは整流器、２４は
絶縁体。A is the melt, B is the molten slag, R is the ground resistance, N is the center point of the resistance, L 1 and L 2 are the ground wire, Ig is the ground fault current,
3 is a melting furnace main body, 3a is a furnace material, 3b is an iron shell, 4 is a graphite main electrode, 5 is a graphite start electrode, 6 is a furnace bottom electrode, 8 is a DC power supply, 8a is a power transformer, 8b is a rectifier, 24 Is an insulator.
───────────────────────────────────────────────────── フロントページの続き (51)Int.Cl.7 識別記号 ＦＩ テーマコート゛(参考） Ｆ２３Ｇ 5/00 １１５ Ｆ２７Ｂ 3/28 ４Ｋ０５６ Ｆ２７Ｂ 3/28 Ｆ２７Ｄ 21/00 Ａ Ｆ２７Ｄ 21/00 Ｂ０９Ｂ 3/00 ３０３Ｌ Ｆターム(参考） 3K061 AA23 AB03 AC02 AC03 BA03 BA06 CA12 DA13 DB06 DB20 3K062 AA23 AB03 AC02 AC03 BA02 BB01 CB03 DA40 DB14 4D004 AA02 AA36 AA37 BA02 CA29 CA32 CB31 CB32 DA03 DA20 4D059 AA03 BB04 EA20 EB20 4K045 AA04 BA07 DA01 RB02 4K056 AA05 BA02 BB08 CA20 FA19──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. 7 Identification symbol FI Theme coat ゛ (Reference) F23G 5/00 115 F27B 3/28 4K056 F27B 3/28 F27D 21/00 A F27D 21/00 B09B 3/00 303L F-term (Reference) 3K061 AA23 AB03 AC02 AC03 BA03 BA06 CA12 DA13 DB06 DB20 3K062 AA23 AB03 AC02 AC03 BA02 BB01 CB03 DA40 DB14 4D004 AA02 AA36 AA37 BA02 CA29 CA32 CB31 CB32 DA03 DA20 4D0 A04 A04 A04 A04 A04 A04 A04 A04 A04 A04 A04 A04 A04 A04 A04 A04 A04 A04 A04 A04 A04 A04 A04 A04 A04 A04 A04 A04 A04 A04 A04 A04 A04 BA02 BB08 CA20 FA19
Claims (4)
ら成る溶融炉本体と、当該溶融炉本体へ電気エネルギー
を供給する直流電源装置とを備えた電気溶融炉に於い
て、前記溶融炉本体の鉄皮を接地すると共に、前記直流
電源装置の出力側端子間に接地抵抗を介挿してその中間
部を接地し、溶融炉本体の運転中前記鉄皮側の接地線又
は接地抵抗側の接地線に流れる地絡電流を連続的に検出
して、当該地絡電流の検出値から炉材の電気絶縁性能の
劣化を検知して運転・停止を制御するようにしたことを
特徴とする電気溶融炉の運転方法。1. An electric melting furnace comprising: a melting furnace main body composed of an electrically insulating furnace material and a shell covering the furnace material; and a DC power supply for supplying electric energy to the melting furnace main body. While grounding the steel shell of the melting furnace main body, grounding the middle part thereof by inserting a grounding resistor between the output side terminals of the DC power supply device, and grounding the ground side or grounding the steel shell side during operation of the melting furnace main body. The ground fault current flowing in the ground wire on the resistance side is continuously detected, and the operation and shutdown are controlled by detecting the deterioration of the electrical insulation performance of the furnace material from the detected value of the ground fault current. Method of operating an electric melting furnace.
（Ω）とすると共に、抵抗値の中間点を接地するように
した請求項１に記載の電気溶融炉の運転方法。2. The magnitude of the ground resistance is set to 1400 to 1600.
The method for operating an electric melting furnace according to claim 1, wherein (Ω) is set, and an intermediate point of the resistance value is grounded.
を配設した構成とした請求項１に記載の電気溶融炉の運
転方法。3. The method for operating an electric melting furnace according to claim 1, wherein the melting furnace main body has a configuration in which an insulating material is provided between the iron shell and the electrode.
の約１０倍を越えたとき、炉材の電気絶縁性能が劣化し
たと判断して運転を停止するようにした請求項１に記載
の電気溶融炉の運転方法。4. The method according to claim 1, wherein when the detected value of the ground fault current exceeds about 10 times the detected value in the steady operation, the operation is stopped upon judging that the electrical insulation performance of the furnace material has deteriorated. 3. The method for operating an electric melting furnace according to claim 1.
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|---|---|---|---|
| JP2000088652A JP3764624B2 (en) | 2000-03-28 | 2000-03-28 | Operation method of electric melting furnace |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2000088652A JP3764624B2 (en) | 2000-03-28 | 2000-03-28 | Operation method of electric melting furnace |
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| Publication Number | Publication Date |
|---|---|
| JP2001272019A true JP2001272019A (en) | 2001-10-05 |
| JP3764624B2 JP3764624B2 (en) | 2006-04-12 |
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|---|---|---|---|
| JP2000088652A Expired - Fee Related JP3764624B2 (en) | 2000-03-28 | 2000-03-28 | Operation method of electric melting furnace |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2008223060A (en) * | 2007-03-09 | 2008-09-25 | Ihi Corp | Vacuum carburization method and vacuum carburizing apparatus |
| US8465598B2 (en) | 2006-09-27 | 2013-06-18 | Ihi Corporation | Vacuum carburization processing method and vacuum carburization processing apparatus |
| KR101447536B1 (en) * | 2013-10-16 | 2014-10-13 | 한미전기로(주) | Metal leak and insulation detector for induction melting furnace |
-
2000
- 2000-03-28 JP JP2000088652A patent/JP3764624B2/en not_active Expired - Fee Related
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8465598B2 (en) | 2006-09-27 | 2013-06-18 | Ihi Corporation | Vacuum carburization processing method and vacuum carburization processing apparatus |
| JP2008223060A (en) * | 2007-03-09 | 2008-09-25 | Ihi Corp | Vacuum carburization method and vacuum carburizing apparatus |
| US8152935B2 (en) | 2007-03-09 | 2012-04-10 | Ihi Corporation | Vacuum carburization method and vacuum carburization apparatus |
| US20120180717A1 (en) * | 2007-03-09 | 2012-07-19 | Ihi Corporation | Vacuum carburization method and vacuum carburization apparatus |
| US8741061B2 (en) | 2007-03-09 | 2014-06-03 | Ihi Corporation | Vacuum carburization method and vacuum carburization apparatus |
| KR101447536B1 (en) * | 2013-10-16 | 2014-10-13 | 한미전기로(주) | Metal leak and insulation detector for induction melting furnace |
Also Published As
| Publication number | Publication date |
|---|---|
| JP3764624B2 (en) | 2006-04-12 |
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