JP3032400B2 - NOx reduction method in plasma furnace - Google Patents
NOx reduction method in plasma furnaceInfo
- Publication number
- JP3032400B2 JP3032400B2 JP5109919A JP10991993A JP3032400B2 JP 3032400 B2 JP3032400 B2 JP 3032400B2 JP 5109919 A JP5109919 A JP 5109919A JP 10991993 A JP10991993 A JP 10991993A JP 3032400 B2 JP3032400 B2 JP 3032400B2
- Authority
- JP
- Japan
- Prior art keywords
- plasma
- gas
- furnace
- fuel
- nox
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
Landscapes
- Incineration Of Waste (AREA)
- Gasification And Melting Of Waste (AREA)
Description
【０００１】[0001]
【産業上の利用分野】本発明は、プラズマアークにより
高温で廃棄物を溶融させる（可燃物を含む場合には焼却
を伴って溶融する）プラズマ炉から生じる排ガスの低Ｎ
Ｏｘを実現するための運転方法に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for melting waste gas at a high temperature by means of a plasma arc (melting with incineration when combustibles are contained).
The present invention relates to a driving method for realizing Ox.
【０００２】[0002]
【従来の技術】下水汚泥、都市ごみ、産業廃棄物、自動
車シュレッダーダスト等の廃棄物は、これまで燃焼法に
より焼却された後に焼却灰として埋め立て処分された
り、また焼却されずそのまま埋め立て処分されてきた。
しかし最近は埋め立て処分地の確保が難しくなり、その
ままではなく減容化して埋め立て処分地の延命化が必要
となってきた。また、焼却灰の埋め立て時には有害物質
の濃縮や重金属の地下水への溶出が問題になる。2. Description of the Related Art Waste such as sewage sludge, municipal solid waste, industrial waste, and automobile shredder dust has hitherto been incinerated by a combustion method and then landfilled as incinerated ash, or landfilled without incineration. Was.
Recently, however, it has become difficult to secure landfill sites, and it has become necessary to extend the life of landfill sites by reducing the volume instead of keeping the landfill. In addition, when reclaiming incinerated ash, harmful substances are concentrated and heavy metals are eluted into groundwater.
【０００３】そこで、廃棄物を焼却且つ溶融して体積を
減らし、または廃棄物焼却灰を溶融して無害化し、更に
溶融固化したスラグを骨材や路盤材などの建設資材とし
て有効活用するようになった。この廃棄物又は廃棄物焼
却灰の溶融には、旋回流溶融炉、表面溶融炉およびコー
クスベッド法などの燃焼法もあるが、プラズマアークの
電気プラズマ熱を使用するプラズマ炉が着目されてい
る。[0003] Therefore, the waste is incinerated and melted to reduce the volume, or the waste incineration ash is melted to make it harmless, and the molten and solidified slag is effectively used as construction material such as aggregate and roadbed material. became. For melting this waste or waste incineration ash, there are combustion methods such as a swirling flow melting furnace, a surface melting furnace, and a coke bed method. However, a plasma furnace using electric plasma heat of a plasma arc has attracted attention.
【０００４】このプラズマ炉は約１万度の高温のプラズ
マアークを用いるのでダイオキシンなどの有害物質の分
解が容易に行えると共に、燃焼法に比べて排ガス量が３
０分の１以下であるために、排ガス処理設備がコンパク
トになる利点がある。一方、プラズマアークが高温にな
るためＮＯｘを多量に発生する問題があり、特にプラズ
マガスとして空気を使用した場合には数１０００ｐｐｐ
ｍの高濃度のＮＯｘを発生する。Since this plasma furnace uses a high-temperature plasma arc of about 10,000 degrees, it can easily decompose harmful substances such as dioxin, and has an exhaust gas amount of 3 times as compared with the combustion method.
Since it is 1/0 or less, there is an advantage that the exhaust gas treatment equipment becomes compact. On the other hand, there is a problem that a large amount of NOx is generated due to the high temperature of the plasma arc. In particular, when air is used as the plasma gas, several thousand ppp
m of NOx at a high concentration.
【０００５】このため、特開平２−１２２１０９号公報
では、焼却灰を高温下で溶融処理するに当たり、プラズ
マ炉にコークス、石炭、木炭、可燃性ごみ、下水汚泥な
どの炭素源または炭水化物源を別途に投入添加し、還元
性雰囲気にて焼却灰を溶融し、低ＮＯｘを実現する運転
方法が提案されている。[0005] For this reason, in Japanese Patent Application Laid-Open No. 2-122109, when melting incinerated ash at a high temperature, a carbon source or a carbohydrate source such as coke, coal, charcoal, combustible waste and sewage sludge is separately provided in a plasma furnace. An operation method has been proposed in which the incineration ash is melted in a reducing atmosphere to achieve low NOx.
【０００６】[0006]
【発明が解決しようとする課題】しかしながら、この運
転方法によると炉内を安定して還元性雰囲気にするため
には多量の炭素源または炭水化物源を投入せざるを得な
いという問題点がある。即ち、投入されたコークス、石
炭、木炭などは不定型の固体であり、スラグ浴の表面上
に供給された後で加熱され溶融しながらガス化された
り、落下と同時にガス化されたりするので還元性ガスの
発生量が不安定になり易いため、炉内を還元性雰囲気に
確実に保つためには多量の炭素源または炭水化物源を供
給する必要がある。However, according to this operation method, there is a problem that a large amount of a carbon source or a carbohydrate source has to be supplied in order to stabilize the inside of the furnace to a reducing atmosphere. That is, the injected coke, coal, charcoal, etc. are amorphous solids, which are supplied on the surface of the slag bath, heated and melted to gasify, or dropped and gasified at the same time. Since the generation amount of the reactive gas is likely to be unstable, it is necessary to supply a large amount of a carbon source or a carbohydrate source in order to reliably maintain the inside of the furnace in a reducing atmosphere.
【０００７】また、コークス、石炭、木炭などの不定型
固体を別途の供給装置を設けて炉内へ投入することは設
備費が高くなり、定量供給も難しい。更に、溶融炉と移
動するプラズマトーチの間に隙間ができ易く、溶融炉の
シールを完全にすることは難しく、隙間からのＣＯ等の
還元性ガスの外部への排出が問題となる。Further, it is difficult to provide a fixed supply of amorphous solids such as coke, coal, charcoal and the like into a furnace by providing a separate supply device, which increases equipment costs and makes it difficult to supply a fixed amount. Further, a gap is easily formed between the melting furnace and the moving plasma torch, and it is difficult to completely seal the melting furnace. Discharge of a reducing gas such as CO from the gap to the outside becomes a problem.
【０００８】[0008]
【発明が解決しようとする課題】本発明は、従来の技術
の有するこのような問題点に鑑みてなされたものであ
り、その目的とするところは、プラズマ炉で廃棄物を溶
融処理するにあたり、低コストで容易にＮＯｘの発生を
抑制できるプラズマ炉のＮＯｘ低減方法を提供するとこ
ろにある。SUMMARY OF THE INVENTION The present invention has been made in view of such problems of the prior art, and an object thereof is to melt waste in a plasma furnace. An object of the present invention is to provide a method for reducing NOx in a plasma furnace which can easily suppress NOx generation at low cost.
【０００９】[0009]
【課題を解決するための手段】上記目的を達成する本発
明のプラズマ炉の運転方法は、プラズマ炉の排ガス中に
燃料を吹き込むことを基本とする方法である。吹き込み
位置は好ましくは排気孔又は排気孔兼用のスラグ排出孔
であり、吹き込み位置の温度は好ましく５００°Ｃ以上
であり、プラズマガス量が変動する場合には前記燃料の
量を連動させて変動させることが好ましい。ここで燃料
は吹き込み可能なものであればよく、都市ガス、ブタン
ガス等の気体燃料が最適であり、灯油やＡ重油等の燃焼
性の良好な液体燃料でもよく、多少の粉体燃料が混じっ
たものでもよい。The method for operating a plasma furnace according to the present invention, which achieves the above object, is a method based on blowing fuel into exhaust gas from a plasma furnace. The blowing position is preferably an exhaust hole or a slag discharge hole that also serves as an exhaust hole, and the temperature of the blowing position is preferably 500 ° C. or higher. When the plasma gas amount fluctuates, the amount of the fuel is fluctuated in conjunction therewith. Is preferred. Here, the fuel may be any as long as it can be blown, and a gas fuel such as city gas or butane gas is optimal, and a liquid fuel having good flammability such as kerosene or heavy oil A may be used, and some powder fuel is mixed. It may be something.
【００１０】また、プラズマ炉の排気孔に燃料を吹き込
み、更にその下流で燃焼用空気を吹き込み、この燃焼用
空気の吹き込み位置の温度を好ましくは８００°Ｃ以上
とする方法がある。Further, there is a method in which fuel is blown into an exhaust hole of a plasma furnace, and further, combustion air is blown downstream thereof, and the temperature of the combustion air blowing position is preferably 800 ° C. or higher.
【００１１】[0011]
【作用】ＮＯｘを大量に含んだ排ガスは排気孔又は排気
孔兼用のスラグ排出孔から流出するので、この排気孔又
は排気孔兼用のスラグ排出孔に例えばＣＯを含む都市ガ
スを吹き込むと、この排気孔又は排気孔兼用のスラグ排
出孔は還元性ガスであるＣＯ，Ｈ2 の燃焼状態となり、
ＮＯｘが還元される。吹き込み位置の温度が５００°Ｃ
以上であると、燃料が着火し、還元性ガスとなる。The exhaust gas containing a large amount of NOx flows out from the exhaust hole or the slag discharge hole also serving as the exhaust hole. When city gas containing, for example, CO is blown into the exhaust hole or the slag discharge hole also serving as the exhaust hole, the exhaust gas is exhausted. The holes or the slag discharge holes also serving as exhaust holes are in a state of combustion of CO and H 2 as reducing gases,
NOx is reduced. The temperature at the blowing position is 500 ° C
With the above, the fuel ignites and becomes a reducing gas.
【００１２】また、ＮＯｘを還元後の排出孔又は排気孔
兼用のスラグ排出孔からの排ガスに燃焼用空気を吹込
み、還元性ガスを完全燃焼させてＣＯ、Ｈ2 などの還元
性ガスの排出を抑制する。吹き込み位置の温度が８００
°Ｃ以上であると、大気放出されるＣＯ濃度が１００ｐ
ｐｍ以下に抑制される。Further, combustion air is blown into exhaust gas from a discharge hole after reducing NOx or a slag discharge hole also serving as an exhaust hole, and the reducing gas is completely burned to discharge a reducing gas such as CO and H 2. Suppress. 800 at the blowing position
° C or higher, the concentration of CO released to the atmosphere is 100p
pm or less.
【００１３】[0013]
【実施例】以下本発明の実施例を図面に従って説明す
る。図１はプラズマ炉を示す。まずプラズマ炉の構造を
説明し、次に運転方法を説明する。Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a plasma furnace. First, the structure of the plasma furnace will be described, and then the operation method will be described.
【００１４】図１において、炉本体１は外壁を水冷し、
内側を耐火物構造として炉壁放散熱を最少限化すると共
に炉寿命を延長させている。プラズマトーチ２は上部か
ら炉内に挿入され、高温のプラズマアーク３を作り、炉
内を高温に保つ。廃棄物４は、図示されないスクリュー
フィーダーやベルトコンベアなどの一般的な供給装置に
より炉内に供給される。この廃棄物４は、プラズマアー
ク３により加熱されて溶け、スラグ浴１５を形成する。
更に廃棄物４を炉内へ供給し続けるとスラグ６がスラグ
排出孔７からオーバーフローして炉外へ排出される。こ
のスラグ６は水または空気で冷却されて、コンベア等の
搬送手段９で輸送されて、図示されないコンテナバッグ
又は貯蔵ビンに貯えられる。プラズマ溶融炉の排ガス１
３は、排気孔１６を経て排ガス１４となり煙道１１の上
側から図示されない集じん機を経て大気放散される。こ
の排気孔１６の入口には、ＮＯｘを低減するために気体
（都市ガス、ブタンガス等）又は液体（灯油やＡ重油
等）の如く吹き込み可能な燃料５の噴射孔８を設けて、
燃料５を排ガス１３中に噴射させ均一に混合させつつ燃
焼させ、還元性ガス雰囲気にして、ＮＯｘを還元する。
また排気孔１６からの排ガス１３に残る還元性ガスを、
煙道１１に設けられた燃焼用空気の吹き込みノズルまた
はバーナ１０で完全燃焼させ、排ガス１４となり煙道１
１の上側から図示されない集じん機を経て大気放散され
る。In FIG. 1, a furnace main body 1 has an outer wall water-cooled,
The inside has a refractory structure to minimize the heat dissipated from the furnace wall and extend the life of the furnace. The plasma torch 2 is inserted into the furnace from above to create a high-temperature plasma arc 3 and keep the inside of the furnace at a high temperature. The waste 4 is supplied into the furnace by a general supply device such as a screw feeder or a belt conveyor (not shown). The waste 4 is heated and melted by the plasma arc 3 to form a slag bath 15.
Further, when the waste 4 is continuously supplied into the furnace, the slag 6 overflows from the slag discharge hole 7 and is discharged out of the furnace. The slag 6 is cooled by water or air, transported by transport means 9 such as a conveyor, and stored in a container bag or storage bin (not shown). Exhaust gas from plasma melting furnace 1
The exhaust gas 3 becomes exhaust gas 14 through an exhaust hole 16 and is released from the upper side of the flue 11 to the atmosphere through a dust collector (not shown). At the inlet of the exhaust hole 16, an injection hole 8 of a fuel 5 that can be blown like a gas (city gas, butane gas, etc.) or a liquid (kerosene, A heavy oil, etc.) is provided to reduce NOx.
The fuel 5 is injected into the exhaust gas 13 and burned while being uniformly mixed, thereby reducing the NOx in a reducing gas atmosphere.
The reducing gas remaining in the exhaust gas 13 from the exhaust hole 16 is
The fuel is completely burned by a combustion air blowing nozzle or a burner 10 provided in the flue 11 to become exhaust gas 14 and the flue 1
The air is released from the upper side of the device 1 through a dust collector (not shown).
【００１５】プラズマトーチ２には様々なタイプの物が
あり、プラズマガスもＡｒ、Ｎ2 、空気など様々なガス
が使われる。コスト的にはプラズマガスとして空気を使
用する場合が最も安いので広く使われている。この場合
には、空気中のＮ2 とＯ2 が高温のプラズマ炎（アーク
炎）の中で反応して高濃度のＮＯｘを発生する。このＮ
Ｏｘは、光化学スモッグや酸性雨などの公害の原因物質
であり、排出ガス１３に含まれたまま排出される。そこ
で噴射孔８から気体又は液体の燃料好ましくは気体燃料
５を排ガス１３中に噴射させ均一に混合し、還元性ガス
の燃焼状態とし、ＮＯｘを還元して低減する。プラズマ
ガスの空気量は、出力３００ｋｗクラスで１０〜３０Ｎ
ｍ3 ／Ｈ，１．５ＭＷで８０〜１２０Ｎｍ3 ／Ｈ程度で
あり、排ガス１３中のＯ2 は廃棄物中に可燃分が無い場
合は約２１％である。従って燃料はＮＯｘ低減効果を高
めるために、排ガス量とＯ2 濃度を勘案して還元性ガス
が発生するように気体燃料又は液体燃料を吹込めば良
い。上記の条件例で気体燃料として１３Ａ都市ガスを吹
込む場合の吹込み量は、３００ｋｗクラスでわずか１〜
３Ｎｍ3 ／Ｈ，１．５ＭＷで８〜１２Ｎｍ3 ／Ｈ程度と
なる。勿論、廃棄物中に可燃分が含まれる場合には、プ
ラズマ空気中のＯ2 が消費されるので、吹込み都市ガス
量が少なくて済むことになる。またこの都市ガスが炉内
に逆流しないので、炉とトーチ２の隙間から漏れる排ガ
スにＣＯ等の有害物質が紛れ込む恐れがない。There are various types of plasma torches 2, and various gases such as Ar, N 2 and air are used as the plasma gas. The use of air as the plasma gas is widely used since it is the cheapest in terms of cost. In this case, N 2 and O 2 in the air react in a high-temperature plasma flame (arc flame) to generate a high concentration of NOx. This N
Ox is a substance causing pollution such as photochemical smog and acid rain, and is emitted while being contained in the exhaust gas 13. Therefore, gaseous or liquid fuel, preferably gaseous fuel 5, is injected into the exhaust gas 13 from the injection holes 8 and uniformly mixed to make a reducing gas combustion state, and NOx is reduced and reduced. The air amount of the plasma gas is 10 to 30 N in the output 300 kW class.
It is about 80 to 120 Nm 3 / H at m 3 / H and 1.5 MW, and O 2 in the exhaust gas 13 is about 21% when there is no combustible component in the waste. Therefore, in order to enhance the NOx reduction effect, gaseous fuel or liquid fuel may be injected into the fuel so as to generate a reducing gas in consideration of the exhaust gas amount and the O 2 concentration. In the case of 13A city gas as the gaseous fuel in the above condition example, the amount of injection is only 1 to 300 kW class.
At 3 Nm 3 / H, 1.5 MW, it is about 8 to 12 Nm 3 / H. Of course, when combustibles are contained in the waste, O 2 in the plasma air is consumed, so that the amount of the blown city gas can be reduced. In addition, since the city gas does not flow back into the furnace, there is no possibility that harmful substances such as CO may be mixed into exhaust gas leaking from a gap between the furnace and the torch 2.
【００１６】ここで、燃料噴射孔８の位置は、図１のよ
うに排ガス１３との良好な混合を保ち、高温燃焼できる
ように排気孔１６の炉内側（入口部）に設けることが好
ましいが、煙道１１に設けても良い。この場合の気体ま
たは液体燃料の吹込み位置温度は少なくとも各燃料の着
火温度以上ならば良く、５００℃以上が良い。また、Ｎ
Ｏｘの低減効果を高めるためには、吹込み燃料を残存酸
素量を消費するよりも多量に吹込み、ＣＯ，Ｈ2 などの
還元性ガスを発生させるので、煙道１１では空気ノズル
１０から燃焼用空気を吹込み完全燃焼させる必要があ
る。この燃焼用空気の吹込み位置温度は、大気放散され
るＣＯ濃度を１００ｐｐｍ以下に抑制するために８００
℃以上とする必要がある。Here, the position of the fuel injection hole 8 is preferably provided inside the furnace (inlet portion) of the exhaust hole 16 so as to maintain good mixing with the exhaust gas 13 and perform high-temperature combustion as shown in FIG. , May be provided in the flue 11. In this case, the gas or liquid fuel injection position temperature should be at least the ignition temperature of each fuel, and preferably 500 ° C. or more. Also, N
In order to enhance the effect of reducing Ox, the blowing fuel is blown in a larger amount than the consumption of the residual oxygen to generate reducing gas such as CO and H 2. It is necessary to blow in the working air and complete combustion. The temperature at which the combustion air is injected is set at 800 to suppress the concentration of CO released to the atmosphere to 100 ppm or less.
It is necessary to be higher than ° C.
【００１７】また、超高温空気はプラズマトーチ２の銅
電極等を酸化させやすい。そこでトーチ２の寿命を長く
保つために、プラズマガス空気量を周期的に変動させて
いる。即ち、プラズマガス量を周期的に変動させると、
超高温のプラズマの発生点が電極内で移動するので電極
の消耗量が一様になり電極寿命が長くなる。従来の如く
プラズマ炉内に不定型固体の炭素源または炭水化物源を
別途投入添加する場合には、これら不定型固体がガス
化、溶融して還元ガスを発生するまでに時間がかかり、
かつ固体の種類または大きさによって大幅に還元性ガス
発生速度が異なるためＮＯｘ低減効果を高めるための多
量の固体の炭素源または炭水化物源を加える必要があ
り、応答性が低くなる。一方本発明では都市ガスなど還
元性ガスを有した気体のような燃料５を使用し、吹込み
と同時に還元性ガスとなりＮＯｘを還元できるので、少
量でＮＯｘ低減効果が非常に大きく取扱いも容易であ
る。そこでプラズマガス量の周期的変動と連動させた燃
料５の吹き込みも簡単にでき、還元性ガス量を適切に保
つことによってＮＯｘをより低いレベルまで低減でき
る。Further, the ultra-high temperature air easily oxidizes the copper electrode and the like of the plasma torch 2. Therefore, in order to keep the life of the torch 2 long, the plasma gas air amount is periodically changed. That is, when the plasma gas amount is periodically changed,
Since the point of generation of the ultra-high temperature plasma moves within the electrode, the amount of consumption of the electrode becomes uniform and the life of the electrode is prolonged. When a carbon source or a carbohydrate source of an amorphous solid is separately charged and added into a plasma furnace as in the past, it takes time until these amorphous solids are gasified and melted to generate a reducing gas,
In addition, since the reducing gas generation rate greatly differs depending on the type or size of the solid, it is necessary to add a large amount of a solid carbon source or a carbohydrate source to enhance the NOx reduction effect, and the response becomes low. On the other hand, in the present invention, a fuel 5 such as a gas having a reducing gas such as a city gas is used, and the NOx can be reduced at the same time as the blowing, and the NOx can be reduced. is there. Therefore, the injection of the fuel 5 in conjunction with the periodic fluctuation of the plasma gas amount can be easily performed, and NOx can be reduced to a lower level by appropriately maintaining the reducing gas amount.
【００１８】つぎに、具体的な実施例について説明す
る。図１に示すプラズマ炉を使用して都市ごみ焼却灰２
５０ｋｇ／Ｈをノントランスファータイププラズマトー
チ３００ｋｗの出力で溶融した。プラズマガスとして空
気を使用し、そのガス量は平均値２１Ｎｍ3 ／Ｈとし±
２０％で空気量を周期的に変動させている。Next, a specific embodiment will be described. Municipal solid waste incineration ash 2 using the plasma furnace shown in FIG.
50 kg / H was melted with a non-transfer type plasma torch output of 300 kW. Air was used as the plasma gas, and the gas amount was set to an average value of 21 Nm 3 / H ±
The air amount is periodically changed at 20%.
【００１９】燃料の吹き込み量によって、ＣＯ濃度及び
ＮＯｘ低減率がどのように変化するか調べた結果を図２
に示す。なお燃料５として都市ガス１３Ａ（メタン８８
％，エタン６％，プロパン４％，ブタン２％）を噴射孔
８から排ガス１３中に噴射した。都市ガス吹込み量が１
Ｎｍ3 ／Ｈの条件ではＣＯ濃度は１００ｐｐｍ以下でＮ
Ｏｘ低減率は４６％程度となる。更に都市ガス吹込み量
を２Ｎｍ3 ／Ｈから４Ｎｍ3 ／Ｈまで増加させると、
（Ａ）曲線の○印データのように、ＣＯ濃度が上昇し、
ＮＯｘ低減率が約９０％程度まで大きくなる。また煙道
において大気を吸い込んでＣＯ濃度を減少させている
が、それでも相当高くなる。そこで、煙道に更に燃焼用
空気を吹き込みノズル１０から空気を２０〜３０Ｎｍ3
／Ｈ強制的に吹込み排ガスと混合させ、ＣＯの発生を抑
制した結果が（Ｂ）曲線の×印データであり、ＮＯｘ低
減率は９０〜９２％と変わらないが、ＣＯを１００ｐｐ
ｍ以下に低減できた。FIG. 2 shows the results of examining how the CO concentration and the NOx reduction rate change depending on the amount of fuel injected.
Shown in Note that city gas 13A (methane 88
%, Ethane 6%, propane 4%, butane 2%) were injected into the exhaust gas 13 from the injection hole 8. City gas injection volume is 1
Under the condition of Nm 3 / H, the CO concentration is 100 ppm or less and N
The Ox reduction rate is about 46%. When further increase the city gas blowing amount from 2 Nm 3 / H to 4 Nm 3 / H,
(A) As indicated by the data marked with a circle in the curve, the CO concentration increases,
The NOx reduction rate increases to about 90%. In addition, although the air is sucked into the flue to reduce the CO concentration, it is still considerably high. Then, the combustion air is further blown into the flue, and the air is emitted from the nozzle 10 by 20 to 30 Nm 3.
/ H forcibly mixed with the blown exhaust gas to suppress the generation of CO is the x-mark data of the curve (B), and the NOx reduction rate does not change from 90 to 92%, but CO is reduced to 100 pp.
m or less.
【００２０】図３は他のプラズマ炉の断面図である。図
１のものと異なる点は、スラグ排出孔７が排ガス１３の
排出孔兼用となっている点である。この場合もスラグ排
出孔７の入口に燃料５の噴射孔８が設けられている。図
１のものと同様に排ガス１３を還元性雰囲気にしてＮＯ
ｘを低減させると共に、スラグ排出孔の加熱も同時にで
き、スラグ６の安定出滓を達成することができる。FIG. 3 is a sectional view of another plasma furnace. 1 in that the slag discharge hole 7 is also used as a discharge hole for the exhaust gas 13. Also in this case, an injection hole 8 for the fuel 5 is provided at the entrance of the slag discharge hole 7. As in the case of FIG.
In addition to reducing x, heating of the slag discharge hole can be performed at the same time, and stable slag discharge of the slag 6 can be achieved.
【００２１】通常プラズマ溶融炉は燃焼溶融炉に比較す
ると排ガス量が約３０分の１以下と少量である。そのた
めプラズマ溶融炉のスラグ排出孔７の出口付近を高温に
保つことが難しく、スラグ排出孔７の出口にスラグ６が
固まり出滓不能になったり、炉内の炉圧制御ができず浮
遊したいるばいじんが大気に放出されて環境を悪くす
る。しかし噴射孔８から吹き込まれた燃料は、スラグ排
出孔７の中で排ガス１３と良く混合して狭い空間で燃焼
し、高熱を発生する。この結果スラグ排出孔７の全域が
高温に保たれ、スラグ排出孔７の出口付近も高温にな
り、スラグ排出孔７の閉塞を防止するという効果を奏す
る。したがってスラグ排出孔７の全域を高温に保つため
に、燃料噴射孔をスラグ排出孔７の入口に設ける。Normally, a plasma melting furnace has a small amount of exhaust gas of about 1/30 or less as compared with a combustion melting furnace. Therefore, it is difficult to keep the temperature near the outlet of the slag discharge hole 7 of the plasma melting furnace at a high temperature, and the slag 6 is solidified at the outlet of the slag discharge hole 7 so that the slag 6 cannot be removed, or the furnace pressure in the furnace cannot be controlled, and the slag 6 floats. Soot and dust are released into the atmosphere, causing environmental damage. However, the fuel blown from the injection hole 8 mixes well with the exhaust gas 13 in the slag discharge hole 7 and burns in a narrow space to generate high heat. As a result, the entire area of the slag discharge hole 7 is maintained at a high temperature, the temperature near the outlet of the slag discharge hole 7 also becomes high, and there is an effect that the slag discharge hole 7 is prevented from being blocked. Therefore, a fuel injection hole is provided at the inlet of the slag discharge hole 7 in order to keep the entire area of the slag discharge hole 7 at a high temperature.
【００２２】つぎに、図３のタイプのプラズマ炉による
具体的な実施例を以下に説明する。図３に示すプラズマ
炉を使用して都市ごみ焼却灰３００ｋｇ／Ｈをノントラ
ンスファータイププラズマトーチ３００ｋｗの出力で溶
融した。プラズマガス量は１５〜２５Ｎｍ3 ／Ｈの範囲
で３分周期で流量変動させた。また煙道１１で未燃ガス
を燃焼させるために、吹き込みノズル１０から燃焼用空
気を２０Ｎｍ3 ／Ｈ吹き込みＣＯの排出を抑制した。上
述した都市ガス１３Ａの３．０Ｎｍ3 ／Ｈを噴射孔８か
ら吹き込んだところ、ＮＯｘ低減率は時間平均で９３．
７％が得られた。この場合、プラズマガス量が変動する
のに対して、吹き込む都市ガスの流量を一定にしていた
ため、還元度がプラズマガス量が多い場合に低く、ＮＯ
ｘ低減率が小さくなり、一方プラズマガス量が少ない合
に低く、ＮＯｘ低減率が大きくなり、時間的変動が大き
かった。そこで、プラズマガス量の変動と同期させて時
間平均３．０Ｎｍ3 ／Ｈを噴射孔８から吹き込んだとこ
ろ、ＮＯｘ低減率は時間平均で９６．４％が得られた。
また、スラグ排出孔７に都市ガスを吹き込まない場合に
は、スラグ排出孔７の出口にスラグ６が固まり、約５時
間に一回程度のメインテナンスが必要であった。しかし
スラグ排出孔７に都市ガスを吹き込むと、スラグ６が固
まるトラブルは完全に解消されメインテナンスが不要と
なった。さらにスラグ６が高温で出滓できるので、スラ
グ６の品質が非常に良く、骨材等に広く利用できるよう
になった。Next, a specific embodiment using a plasma furnace of the type shown in FIG. 3 will be described below. Using the plasma furnace shown in FIG. 3, 300 kg / H of municipal waste incineration ash was melted at an output of a non-transfer type plasma torch 300 kW. The flow rate of the plasma gas was varied in a cycle of 3 minutes within a range of 15 to 25 Nm 3 / H. Further, in order to burn unburned gas in the flue 11, 20 Nm 3 / H of combustion air was blown from the blowing nozzle 10 to suppress the emission of CO. When 3.0 Nm 3 / H of the above-mentioned city gas 13A was blown from the injection hole 8, the NOx reduction rate was 93.times.
7% was obtained. In this case, while the amount of the plasma gas fluctuates, the flow rate of the city gas to be blown was kept constant.
The x reduction rate was low, while the plasma gas amount was low when it was low, the NOx reduction rate was high, and the temporal variation was large. Then, when a time average of 3.0 Nm 3 / H was blown from the injection hole 8 in synchronization with the fluctuation of the plasma gas amount, a NOx reduction rate of 96.4% was obtained on a time average.
When city gas was not blown into the slag discharge hole 7, the slag 6 solidified at the outlet of the slag discharge hole 7, and required maintenance about once every 5 hours. However, when city gas was blown into the slag discharge hole 7, the trouble that the slag 6 solidified was completely eliminated, and maintenance became unnecessary. Further, since the slag 6 can be leached at a high temperature, the quality of the slag 6 is very good, and the slag 6 can be widely used for aggregates and the like.
【００２３】[0023]
【発明の効果】本発明のプラズマ炉の運転方法は、排ガ
ス中に燃料を吹き込んで還元性ガス雰囲気にするので、
排ガスに含まれるＮＯｘは還元され、燃料は有効に還元
に活用されるので、少量の燃料吹込みで容易にＮＯｘを
低減できる。すなわち、吹き込み可能な気体又は液体の
如き燃料であるので、固体燃料に比較して扱い易く、プ
ラズマガスの流動変動周期に同調した吹き込みも可能で
あり、還元性ガスの過不足を最適に保持できる。また炉
内を還元性ガスの雰囲気にするものではないので、炉か
ら漏れる排ガスに有害物質が含まれる恐れは少なくな
る。また排ガスの排出孔兼用のスラグ排出孔に燃料を吹
き込んで燃焼させると、スラグ排出孔の加熱もでき、ス
ラグの安定出滓に寄与する。According to the method for operating a plasma furnace of the present invention, a fuel is blown into exhaust gas to form a reducing gas atmosphere.
Since NOx contained in the exhaust gas is reduced and the fuel is effectively used for the reduction, NOx can be easily reduced with a small amount of fuel injection. That is, since it is a fuel such as a gas or liquid that can be blown, it is easier to handle than a solid fuel, it is possible to blow it in synchronization with the flow fluctuation cycle of the plasma gas, and it is possible to optimally maintain the excess or deficiency of the reducing gas. . Further, since the inside of the furnace is not made to have an atmosphere of a reducing gas, the risk of containing harmful substances in exhaust gas leaking from the furnace is reduced. Further, when fuel is blown into the slag discharge hole also serving as the exhaust gas discharge hole and burned, the slag discharge hole can be heated, which contributes to the stable slag discharge of the slag.
【図１】本発明方法が適用されるプラズマ炉の断面図で
ある。FIG. 1 is a sectional view of a plasma furnace to which the method of the present invention is applied.
【図２】燃料の吹き込み量によるＣＯ濃度及びＮＯｘ低
減率の変化を示すグラフ図である。FIG. 2 is a graph showing changes in CO concentration and NOx reduction rate depending on the amount of fuel injected.
【図３】本発明方法が適用される他のプラズマ炉の断面
図である。FIG. 3 is a sectional view of another plasma furnace to which the method of the present invention is applied.
１ 炉本体 ２ プラズマトーチ ３ プラズマガス ４ 廃棄物 ５ 吹き込み可能な燃料 ６ スラグ ７ スラグ排出孔 ８ 噴射孔 １０ 吹き込みノズル １１ 煙道 １３ 排ガス １５ スラグ浴 １６ 排気孔 DESCRIPTION OF SYMBOLS 1 Furnace main body 2 Plasma torch 3 Plasma gas 4 Waste 5 Injectable fuel 6 Slag 7 Slag discharge hole 8 Injection hole 10 Blow nozzle 11 Flue 13 Exhaust gas 15 Slag bath 16 Exhaust hole
フロントページの続き (51)Int.Cl.7 識別記号 ＦＩ Ｆ２３Ｇ 7/06 ＺＡＢ Ｆ２３Ｇ 7/06 ＺＡＢ Ｆ２３Ｊ 1/00 Ｆ２３Ｊ 1/00 Ｂ (72)発明者 東 康夫 兵庫県神戸市西区高塚台１丁目５番５号 株式会社神戸製鋼所 神戸総合研究所 内 (72)発明者 田頭 成能 兵庫県神戸市西区高塚台１丁目５番５号 株式会社神戸製鋼所 神戸総合研究所 内 (72)発明者 山田 基夫 兵庫県尼崎市若王寺３丁目11番20号 関 西電力株式会社 総合技術研究所内 (56)参考文献 特開 平２−122109（ＪＰ，Ａ) 特開 平４−217710（ＪＰ，Ａ) (58)調査した分野(Int.Cl.7，ＤＢ名) F23G 5/50 ZAB F23G 5/00 115 F23G 7/06 105 F23J 1/00 Continuation of the front page (51) Int.Cl. 7 Identification code FI F23G 7/06 ZAB F23G 7/06 ZAB F23J 1/00 F23J 1/00 B (72) Inventor Yasuo Higashi Yasuo Higashi-ku Kobe-shi Takatsukadai 1-chome No. 5-5 Kobe Steel, Ltd.Kobe Research Laboratory (72) Inventor Shigeno Tabashi 1-5-5 Takatsukadai, Nishi-ku, Kobe City, Hyogo Prefecture Kobe Steel Co., Ltd.Kobe Research Laboratory (72) Inventor Motoo Yamada 3-11-20 Wakao-ji Temple, Amagasaki City, Hyogo Kansai Electric Power Co., Inc. General Research Laboratory (56) References JP-A-2-122109 (JP, A) JP-A-4-217710 (JP, A) (58) Field surveyed (Int.Cl. 7 , DB name) F23G 5/50 ZAB F23G 5/00 115 F23G 7/06 105 F23J 1/00
Claims (5)
ズマ炉の排ガス中に燃料を吹き込むプラズマ炉における
ＮＯｘ低減方法であって、 前記燃料の吹き込み位置がプ
ラズマ炉の排気孔兼用のスラグ排出孔であるプラズマ炉
におけるＮＯｘ低減方法。1. A plasma furnace in which fuel is blown into exhaust gas of a plasma furnace for melting waste by a plasma arc.
A method for reducing NOx, wherein the fuel injection position is
Plasma furnace, which is a slag discharge hole that also serves as a plasma furnace exhaust hole
NOx reduction method in.
°Ｃ以上とする請求項１記載のプラズマ炉におけるＮＯ
ｘ低減方法。2. The temperature of the fuel injection position is 500
2 ° C. or higher.
x reduction method.
量の変動に前記燃料の量を連動させる請求項１記載のプ
ラズマ炉におけるＮＯｘ低減方法。3. The method for reducing NOx in a plasma furnace according to claim 1, wherein the amount of the fuel is linked to a change in the amount of plasma gas due to the plasma arc.
ズマ炉の排気孔兼用のスラグ排出孔に燃料を吹き込み、
更にその下流で燃焼用空気を吹き込むプラズマ炉におけ
るＮＯｘ低減方法。4. A blowing fuel into the slag discharge hole of the exhaust pores combined plasma furnace for melting the waste in a plasma arc,
Further, a method for reducing NOx in a plasma furnace into which combustion air is blown downstream.
８００°Ｃ以上とする請求項４記載のプラズマ炉におけ
るＮＯｘ低減方法。5. The method for reducing NOx in a plasma furnace according to claim 4, wherein the temperature of the combustion air blowing position is 800 ° C. or higher.
Priority Applications (12)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP5109919A JP3032400B2 (en) | 1993-03-08 | 1993-04-12 | NOx reduction method in plasma furnace |
| CA 2135204 CA2135204C (en) | 1993-03-08 | 1994-03-08 | Plasma furnace and a method of operating the same |
| AT94908506T ATE168762T1 (en) | 1993-03-08 | 1994-03-08 | METHOD FOR OPERATING A PLASMA MELTING FURNACE |
| EP19940908506 EP0645584B1 (en) | 1993-03-08 | 1994-03-08 | Method of operating a plasma furnace |
| AT96116254T ATE201863T1 (en) | 1993-03-08 | 1994-03-08 | PLASMA OVEN |
| DK94908506T DK0645584T3 (en) | 1993-03-08 | 1994-03-08 | Process of operating a plasma oven |
| CA 2205529 CA2205529C (en) | 1993-03-08 | 1994-03-08 | Plasma furnace and a method of operating the same |
| PCT/JP1994/000362 WO1994020791A1 (en) | 1993-03-08 | 1994-03-08 | Plasma fusion furnace and method of its operation |
| DE1994627412 DE69427412T2 (en) | 1993-03-08 | 1994-03-08 | Plasma furnace |
| EP19960116254 EP0757972B1 (en) | 1993-03-08 | 1994-03-08 | Plasma furnace |
| DE1994611835 DE69411835T2 (en) | 1993-03-08 | 1994-03-08 | Process for operating a plasma melting furnace |
| US08/556,022 US5579705A (en) | 1993-03-08 | 1995-11-13 | Plasma furnace and a method of operating the same |
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP5-75199 | 1993-03-08 | ||
| JP7519993 | 1993-03-08 | ||
| JP5109919A JP3032400B2 (en) | 1993-03-08 | 1993-04-12 | NOx reduction method in plasma furnace |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH06317311A JPH06317311A (en) | 1994-11-15 |
| JP3032400B2 true JP3032400B2 (en) | 2000-04-17 |
Family
ID=26416356
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP5109919A Expired - Lifetime JP3032400B2 (en) | 1993-03-08 | 1993-04-12 | NOx reduction method in plasma furnace |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3032400B2 (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP4806991B2 (en) * | 2005-07-29 | 2011-11-02 | 日立造船株式会社 | NOx reduction method for exhaust gas from plasma ash melting furnace |
| JP4760702B2 (en) * | 2006-12-27 | 2011-08-31 | 日立造船株式会社 | Leak ammonia reduction method in non-catalytic denitration of non-transfer type ash melting furnace exhaust gas |
-
1993
- 1993-04-12 JP JP5109919A patent/JP3032400B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPH06317311A (en) | 1994-11-15 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| KR100582753B1 (en) | Cyclonic Plasma Pyrolysis/Vitrification System | |
| WO2011114794A1 (en) | Method for supplying combustion air in vertical waste incinerator, and vertical waste incinerator | |
| KR100529826B1 (en) | Device and method for waste processing using Plasma pyrolysis | |
| KR100411606B1 (en) | a trash burn system | |
| EP0645584B1 (en) | Method of operating a plasma furnace | |
| JP3032400B2 (en) | NOx reduction method in plasma furnace | |
| EP1367323A1 (en) | Gasification melting furnace and gasification melting method for combustible refuse and/or burned ash | |
| JP2005180881A (en) | Waste treatment device | |
| JPH10281411A (en) | Combustion of emulsion oxygen | |
| KR100300106B1 (en) | Incinerator Melting System | |
| JP2003042429A (en) | Ash melting furnace equipment for gasifying/melting plasma, and method for its control | |
| JP2000102777A (en) | Heating system for waste | |
| JP3764635B2 (en) | Waste incinerator | |
| JP3060197B2 (en) | Incineration ash melting equipment | |
| JP2957941B2 (en) | Incinerator | |
| JP3744668B2 (en) | Ash melting furnace | |
| JP2799550B2 (en) | Melting furnace | |
| JP2002195519A (en) | Method and system for gasifying/melting refuse | |
| JP3959067B2 (en) | Incinerator | |
| KR100317005B1 (en) | Dissolution method of waste incinerator | |
| JP2005226953A (en) | Incinerator | |
| KR101050557B1 (en) | Plasma module and incinerating facility using plasma | |
| JP2004085010A (en) | Melting treatment device | |
| JP2002168427A (en) | Gasification combustion device and method for waste | |
| JP2006010199A (en) | Melting treatment method of waste |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20090210 Year of fee payment: 9 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20100210 Year of fee payment: 10 |
|
| S111 | Request for change of ownership or part of ownership |
Free format text: JAPANESE INTERMEDIATE CODE: R313117 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20100210 Year of fee payment: 10 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20110210 Year of fee payment: 11 |
|
| R360 | Written notification for declining of transfer of rights |
Free format text: JAPANESE INTERMEDIATE CODE: R360 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20110210 Year of fee payment: 11 |
|
| R370 | Written measure of declining of transfer procedure |
Free format text: JAPANESE INTERMEDIATE CODE: R370 |
|
| S111 | Request for change of ownership or part of ownership |
Free format text: JAPANESE INTERMEDIATE CODE: R313117 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20110210 Year of fee payment: 11 |
|
| R350 | Written notification of registration of transfer |
Free format text: JAPANESE INTERMEDIATE CODE: R350 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20120210 Year of fee payment: 12 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20130210 Year of fee payment: 13 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20140210 Year of fee payment: 14 |
|
| EXPY | Cancellation because of completion of term |