JP2005300068A - Method for control of oxygen concentration and temperature of exhaust gas from rotary hearth reducing furnace - Google Patents
Method for control of oxygen concentration and temperature of exhaust gas from rotary hearth reducing furnace Download PDFInfo
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本発明は製鉄プロセス等で発生する金属酸化物を還元処理し回収する還元処理方法に関するものである。特に、還元炉の排ガスの酸素濃度及び温度を制御する方法に関するものである。 The present invention relates to a reduction treatment method for reducing and recovering metal oxide generated in an iron making process or the like. In particular, the present invention relates to a method for controlling the oxygen concentration and temperature of exhaust gas from a reduction furnace.
製鋼ダスト、高炉ダスト、メッキスラッジ等の酸化鉄や酸化ニッケル等の金属酸化物を還元して金属を回収するための金属酸化物還元炉として、図１及び図２に示すような金属酸化物を石炭やコークス等の還元材と混合して造粒した被処理材１を炉室内を移動する炉床３に載せて、その炉室内を搬送しつつ還元雰囲気下で高温に加熱するインメトコ法と称される方法を適用したものが特許文献１で知られている。 As a metal oxide reduction furnace for recovering metal by reducing metal oxides such as iron oxide and nickel oxide such as steelmaking dust, blast furnace dust, and plating sludge, metal oxides as shown in FIGS. 1 and 2 are used. It is called an in-metoco method in which a material to be treated 1 that is granulated by mixing with a reducing material such as coal or coke is placed on a hearth 3 that moves in the furnace chamber and heated to a high temperature in a reducing atmosphere while being conveyed in the furnace chamber. Japanese Patent Application Laid-Open No. H10-228688 is known to which the method described above is applied.
しかし、この還元処理法では、特許文献２で説明されているとおり、還元炉室に設けたバーナー６を空気比１以下にて燃焼させることによって、該還元炉室に一酸化炭素等の未燃ガスを含む還元性の雰囲気ガスを生じさせている。また、加熱炉室に設けたバーナーは空気比１以上にて燃料ガスを完全燃焼させ十分な発熱をえることによって被処理材を高温度に加熱できるようにしている。
ところが、従来のインメトコ法を代表とする被処理材の搬送移動方向と雰囲気ガスの流動方向が逆となる交流式の回転炉床炉では、加熱炉室と還元炉室とが炉内で連通状態にあり、還元炉室で発生した還元性の雰囲気ガスが加熱炉室を通って排気ダクト３０へ排出されるようにしている。このため、加熱炉室では還元炉室で発生した還元性の雰囲気ガスをも燃焼させその燃焼熱を利用すべく十分なる空気を導入している。しかし、必要以上に空気を導入するとかえって加熱炉室の温度を下げることとなり、燃料原単位を悪化させ排ガス処理設備も大型化するなど不都合を招く。
However, in this reduction treatment method, as explained in
However, in an AC rotary hearth furnace in which the direction of the material to be processed and the flow direction of the atmosphere gas are reversed, such as the conventional in-metoco method, the heating furnace chamber and the reduction furnace chamber are in communication with each other in the furnace. The reducing atmosphere gas generated in the reduction furnace chamber is discharged to the
そこで、特許文献２、特許文献３、及び特許文献４では、安定した還元反応を実現するために炉室内の温度及び酸素濃度を制御する方法が提案されている。
この炉室からの排ガスは高効率での熱回収、及び排ガス基準を達成するため粉塵等を除去するガス清浄化処理が施される。
先行特許及び公知文献には明記されていないが、この炉室からの排ガスは酸素濃度の制御と熱回収及びガス清浄との両立が難しい実態がある。
例えば、特許文献２において炉室内ガスの酸素濃度または一酸化炭素濃度の測定濃度に従い該炉室内に空気を導入し該炉室前炉室で発生した未燃ガスを該炉室で燃焼させると記載されている。しかし、実際には、該炉室内ガス成分は該炉室部位で大きな偏差を有し酸素濃度または一酸化炭素濃度を該炉室内平均値として測定することが実質上不可能である。また、該炉室内ガスの酸素濃度または一酸化炭素濃度の測定濃度に従い該炉室内に空気を導入した結果、該炉室内の未燃ガスが多く該炉室内温度が制御すべき温度範囲を超えて上昇する現象が発生することがある。
Therefore,
The exhaust gas from the furnace chamber is subjected to heat recovery with high efficiency and a gas cleaning process for removing dust and the like in order to achieve the exhaust gas standard.
Although not specified in the prior patents and publicly known documents, the exhaust gas from the furnace chamber is difficult to achieve both oxygen concentration control, heat recovery, and gas cleaning.
For example,
金属酸化物還元炉室では、金属酸化物を還元剤と反応させるため１０００℃程度の高い温度と還元雰囲気、例えば一酸化炭素雰囲気を必要とする。この炉室雰囲気が排気ダクトにそのまま侵入すると、還元雰囲気が排気ダクトに侵入した大気と反応し不必要な発熱や圧力上昇を起こすことがある。そのため、排気ダクト直前のガス流れ上流側の炉室にて２次燃焼空気と称する還元雰囲気ガスを燃焼させる空気を吹き込む必要がある。
しかし、還元雰囲気ガスと２次空気が反応した結果、排気ガスが高温となり排ガスからの熱回収設備上限温度やガス清浄設備上限温度を超えたりする好ましくない事態を招く。このようなことが発生すると還元炉での処理量を低減し排ガス量を下げることにより排ガス温度を下げる操業を余儀なくされる。
本発明は、還元反応を進める炉室内での温度、酸素濃度及び還元ガス濃度を犠牲にすることなく排ガスの温度及び酸素濃度を制御し、廃熱回収とガス清浄化を円滑におこなうものである。
In the metal oxide reduction furnace chamber, a high temperature of about 1000 ° C. and a reducing atmosphere, for example, a carbon monoxide atmosphere are required to react the metal oxide with the reducing agent. If this furnace chamber atmosphere enters the exhaust duct as it is, the reducing atmosphere may react with the air that has entered the exhaust duct, causing unnecessary heat generation and pressure increase. Therefore, it is necessary to blow in air for combusting reducing atmosphere gas called secondary combustion air in the furnace chamber upstream of the gas flow just before the exhaust duct.
However, as a result of the reaction between the reducing atmosphere gas and the secondary air, the exhaust gas becomes high in temperature, leading to an undesirable situation in which the upper limit temperature of the heat recovery equipment from the exhaust gas or the upper limit temperature of the gas cleaning equipment is exceeded. When this occurs, it is necessary to reduce the exhaust gas temperature by reducing the throughput in the reduction furnace and reducing the exhaust gas amount.
The present invention controls exhaust gas temperature and oxygen concentration without sacrificing the temperature, oxygen concentration and reducing gas concentration in the furnace chamber for proceeding the reduction reaction, and smoothly performs waste heat recovery and gas purification. .
本発明は上記課題を解決するためになされたもので、その要旨は以下のとおりである。
（１）３室以上の炉室を有する回転炉床式還元炉における排ガスの酸素濃度及び温度の制御方法であって、排気ダクト中の排ガスの酸素濃度が所定の範囲になるように、排気ダクト直前のガス流れ上流側の炉室ａ内に２次燃焼空気を吹き込む第一の工程と、排気ダクト中の排ガスの温度が所定の範囲になるように、該炉室ａの直前の炉室ｂ内に２次燃焼空気を吹き込む第二の工程を、該所定の範囲の酸素濃度及び温度が共に満たされるまで交互に繰り返すことを特徴とする回転炉床式還元炉における排ガスの酸素濃度及び温度の制御方法。
（２）更に、前記炉室ａの温度が所定の範囲になるように、炉室ａ内の燃料量と１次燃焼空気量を空気比一定の下で変更する第三の工程と、前記炉室ｂの温度が所定の範囲になるように、炉室ｂ内の燃料量及び１次燃焼空気量を空気比一定の下で変更する第四の工程を、前記所定の酸素濃度範囲、前記排ガスの所定の温度範囲、該炉室ａの所定の温度範囲、及び該炉室ｂの所定の温度範囲の全てが満たされるまで、第一から第四の工程を繰り返すことを特徴とする（１）記載の回転炉床式還元炉における排ガスの酸素濃度及び温度の制御方法。
（３）前記炉室ａ、炉室ｂの少なくとも何れかにおいて、２次燃焼空気を吹き込む代わりに、１次燃焼空気比を燃料量一定の下で調整することを特徴とする（１）記載の回転炉床式還元炉における排ガスの酸素濃度及び温度の制御方法。
The present invention has been made to solve the above problems, and the gist thereof is as follows.
(1) A method for controlling the oxygen concentration and temperature of exhaust gas in a rotary hearth reducing furnace having three or more furnace chambers, wherein the exhaust duct has an exhaust duct so that the oxygen concentration in the exhaust duct falls within a predetermined range. The first step of blowing secondary combustion air into the furnace chamber a on the upstream side of the immediately preceding gas flow, and the furnace chamber b immediately before the furnace chamber a so that the temperature of the exhaust gas in the exhaust duct falls within a predetermined range. The second step of blowing the secondary combustion air into the inside is repeated alternately until the oxygen concentration and temperature within the predetermined range are both satisfied. Control method.
(2) Furthermore, a third step of changing the amount of fuel and the amount of primary combustion air in the furnace chamber a under a constant air ratio so that the temperature of the furnace chamber a is in a predetermined range, and the furnace A fourth step of changing the amount of fuel and the amount of primary combustion air in the furnace chamber b under a constant air ratio so that the temperature of the chamber b falls within a predetermined range, the predetermined oxygen concentration range, the exhaust gas The first to fourth steps are repeated until all of the predetermined temperature range, the predetermined temperature range of the furnace chamber a, and the predetermined temperature range of the furnace chamber b are satisfied (1) A method for controlling the oxygen concentration and temperature of exhaust gas in the rotary hearth reducing furnace as described.
(3) The primary combustion air ratio is adjusted under a constant fuel amount instead of blowing secondary combustion air in at least one of the furnace chamber a and the furnace chamber b. A method for controlling the oxygen concentration and temperature of exhaust gas in a rotary hearth reducing furnace.
排ガスの酸素濃度を測定し排気直前のガス流れ上流側の炉室ａ内に燃焼用空気を吹き込むだけでは排ガス温度が上昇するが、本発明を適用し排ガス温度を測定して排気直前炉室ａのその前の炉室ｂ内にも燃焼用空気を吹き込むことにより排気前炉室内一酸化炭素等の還元ガス濃度を低下することが出来るので排ガス中の酸素濃度を不必要な発熱や圧力上昇が発生しない濃度に保ちつつ排ガス温度を安定して制御することが可能となる。 The exhaust gas temperature rises only by measuring the oxygen concentration of the exhaust gas and blowing combustion air into the furnace chamber a upstream of the gas flow immediately before the exhaust, but the exhaust gas temperature is measured by applying the present invention to measure the exhaust gas temperature a By reducing the concentration of reducing gas such as carbon monoxide in the pre-exhaust furnace chamber by injecting combustion air into the previous furnace chamber b, unnecessary heat generation and pressure increase can be achieved. It is possible to stably control the exhaust gas temperature while maintaining a concentration that does not occur.
還元炉の排気ダクトと排気ダクト直前のガス流れ上流側の炉室ａ、炉室ａのその前の炉室ｂ、炉室ｃから構成される装置にて炉室ａ、炉室ｂ、炉室ｃの各々の温度及び雰囲気ガスを制御して炉室内の材料を還元させる。排気ダクトへの入口からダクト径の３倍程度以上下流で排気ガスが完全に混合したと見なせる位置にて排気ダクト中の排ガス酸素濃度を酸素センサー等の酸素濃度分析計で測定し排気ダクト中の酸素濃度が制御目標酸素濃度未満（例えば１％未満）であれば炉室ａの２次燃焼空気量を増加させ、排気ダクト中の酸素濃度が制御目標酸素濃度を超え（例えば２％超）れば炉室ａの２次燃焼空気量を削減する。
次に排気ダクト中の排気ガス温度を熱電対等の温度測定器で測定し制御目標温度を超える（例えば１０２０℃超）であれば炉室ｂの２次燃焼空気量を増加させ、制御目標温度未満（例えば９８０℃未満）であれば炉室ｂの２次燃焼空気量を削減する。
炉室ａ及び炉室ｂの２次燃焼空気は該炉室内の一酸化炭素等の還元雰囲気ガスと反応する。炉室ａにおける二次燃焼空気が還元雰囲気ガスの燃焼に必要な理論空気比以上であれば排気ダクト中で酸素を検出し、理論空気比以下であれば還元雰囲気ガスの未燃焼分が排気ダクト中に流れ込む。排気ダクト中での酸素濃度は理論上は０％以上であれば良いが、高すぎると排ガス量が増加し過大な排ガス処理設備が必要となったりエネルギ効率を悪化させるので、実設備では外乱や制御安定性を考慮して１〜２％を目標とすることが望ましい。
また、排気ダクト中の酸素濃度を目標値に収めるため炉室ａの雰囲気ガスを理論空気比以上で燃焼したことにより炉室ａで必要とする熱量以上となることがあり得る。その場合には排気ダクト中の温度が目標値を超えることになる。排気ダクト中の温度を制御する目的で炉室ａにおける還元雰囲気ガスの濃度を下げるために炉室ｂに２次燃焼空気を投入する。
排気ガスの酸素濃度、温度の制御性を更に向上させるために炉室ａ及び炉室ｂの各々の炉室炉体に炉内雰囲気ガス温度を測定するように設けた熱電対等の温度測定器を用いて測定した各々の炉室温度を用いて当該炉室の燃料量と１次燃焼空気量を空気比一定で同時に制御する。
以上の制御方法をフローチャートに示したのが図３である。
尚、第一の工程と第二の工程の間に第三の工程を実行し、第二の工程の後に第四の工程を実行する等の手段の順序を変えても構わない。
A furnace chamber a, a furnace chamber b, a furnace chamber comprising an exhaust duct of the reduction furnace, a furnace chamber a upstream of the gas flow immediately before the exhaust duct, a furnace chamber b in front of the furnace chamber a, and a furnace chamber c The material in the furnace chamber is reduced by controlling the temperature and atmospheric gas of each of c. The exhaust gas oxygen concentration in the exhaust duct is measured with an oxygen concentration analyzer such as an oxygen sensor at a position where it can be considered that exhaust gas is completely mixed downstream from the entrance to the exhaust duct by about three times the diameter of the duct. If the oxygen concentration is less than the control target oxygen concentration (for example, less than 1%), the amount of secondary combustion air in the furnace chamber a is increased, and the oxygen concentration in the exhaust duct exceeds the control target oxygen concentration (for example, more than 2%). The amount of secondary combustion air in the furnace chamber a is reduced.
Next, if the exhaust gas temperature in the exhaust duct is measured with a temperature measuring device such as a thermocouple and exceeds the control target temperature (for example, more than 1020 ° C.), the amount of secondary combustion air in the furnace chamber b is increased to be less than the control target temperature. If it is (for example, less than 980 ° C.), the amount of secondary combustion air in the furnace chamber b is reduced.
The secondary combustion air in the furnace chamber a and the furnace chamber b reacts with a reducing atmosphere gas such as carbon monoxide in the furnace chamber. If the secondary combustion air in the furnace chamber a is greater than the theoretical air ratio required for the combustion of the reducing atmosphere gas, oxygen is detected in the exhaust duct, and if the secondary combustion air is less than the theoretical air ratio, the unburned portion of the reducing atmosphere gas is the exhaust duct. Flows in. The oxygen concentration in the exhaust duct should theoretically be 0% or more, but if it is too high, the amount of exhaust gas will increase and an excessive exhaust gas treatment facility will be required or energy efficiency will be deteriorated. In view of control stability, it is desirable to target 1 to 2%.
In addition, in order to keep the oxygen concentration in the exhaust duct at a target value, the amount of heat required in the furnace chamber a may be increased by burning the atmosphere gas in the furnace chamber a at a theoretical air ratio or higher. In that case, the temperature in the exhaust duct exceeds the target value. In order to control the temperature in the exhaust duct, secondary combustion air is introduced into the furnace chamber b in order to reduce the concentration of the reducing atmosphere gas in the furnace chamber a.
In order to further improve the controllability of the oxygen concentration and temperature of the exhaust gas, a temperature measuring device such as a thermocouple provided to measure the furnace atmosphere gas temperature in each furnace chamber furnace body of the furnace chamber a and the furnace chamber b. Using each furnace chamber temperature measured using the same, the fuel amount in the furnace chamber and the primary combustion air amount are simultaneously controlled at a constant air ratio.
FIG. 3 shows the above control method in a flowchart.
Note that the order of the means such as executing the third step between the first step and the second step and executing the fourth step after the second step may be changed.
排気ダクト中排気ガスの酸素濃度と温度とを制御するために必要な空気量を炉室ａ及び炉室ｂの２次燃焼空気で調整する代わりに、炉室ａ及び炉室ｂの１次燃焼空気量を変えることで調整することも可能である。
排気ダクトの位置は炉室端部に設定する場合の他に、図７に示すように、乾燥予熱炉室０を有し炉室０と炉室ａとの間に設ける場合にも本発明の適用は有効である。その場合には乾燥予熱炉室０の排ガスとそれ以降の炉室排ガスとを混合する前の炉室ａ経由のみの排ガスの酸素濃度と温度とを測定することにより本発明が有効になる。
Instead of adjusting the amount of air required to control the oxygen concentration and temperature of the exhaust gas in the exhaust duct with the secondary combustion air in the furnace chamber a and the furnace chamber b, the primary combustion in the furnace chamber a and the furnace chamber b It is also possible to adjust by changing the amount of air.
In addition to the case where the position of the exhaust duct is set at the end of the furnace chamber, as shown in FIG. 7, the present invention can be applied to a case where the drying preheating furnace chamber 0 is provided between the furnace chamber 0 and the furnace chamber a. Application is effective. In that case, the present invention becomes effective by measuring the oxygen concentration and temperature of the exhaust gas only through the furnace chamber a before mixing the exhaust gas in the dry preheating furnace chamber 0 and the subsequent furnace chamber exhaust gas.
以下、本発明の実施例について図面を使用しさらに説明する。 Hereinafter, examples of the present invention will be further described with reference to the drawings.
図４は、還元炉室にて酸化物を還元材と反応させている炉室内を示している。炉室ａ及び炉室ｂは炉室内還元雰囲気を燃焼させる２次燃焼空気を供給できる。炉室ｃに燃料と燃焼用空気を反応させるバーナーを有して炉室温度を１０５０℃になるように制御している。炉室ｃから炉室ｂに移動する炉室内ガスは炉室ｂで発生する被処理物から発生する還元ガスと２次燃焼空気が燃焼した排ガスと混合して炉室ｂ内ガスとなる。更に炉室ａでも炉室ｂと同様の反応となり炉室ａ内ガスとなり排ガス処理の誘引ブロワーなどにより吸引されて排ガスとなり排気ダクトに移動する。 FIG. 4 shows the furnace chamber in which the oxide is reacted with the reducing material in the reduction furnace chamber. The furnace chamber a and the furnace chamber b can supply secondary combustion air for burning the reducing atmosphere in the furnace chamber. The furnace chamber c has a burner for reacting fuel and combustion air, and the furnace chamber temperature is controlled to 1050 ° C. The furnace chamber gas moving from the furnace chamber c to the furnace chamber b is mixed with the reducing gas generated from the object to be processed generated in the furnace chamber b and the exhaust gas burned by the secondary combustion air to become the gas in the furnace chamber b. Further, the reaction in the furnace chamber a is the same as that in the furnace chamber b, becomes the gas in the furnace chamber a, is sucked by an exhaust blower induction blower or the like, becomes exhaust gas, and moves to the exhaust duct.
本発明を適用する前は排ガス中の酸素濃度が０％で、ＣＯを３％程度検出していた。排ガス中の酸素濃度を測定して炉室ａのみの２次燃焼空気の吹き込み量を変更する第一の工程を実行したところ排ガスダクト中の酸素濃度は所定の濃度１〜２％にできたが排ガス温度が１０９２℃と高くなった。そこで更に排ガスダクト中の温度を測定し炉室ｂの２次燃焼空気量も変更する第ニの工程を実行し、更に第一と第二の工程を繰り返したところ、約１０分という短時間で、排ガスダクト中の酸素濃度は所定の１〜２％、温度は大半の場合に目標の９８０〜１０２０℃に安定した。 Prior to application of the present invention, the oxygen concentration in the exhaust gas was 0% and CO was detected at about 3%. When the first step of measuring the oxygen concentration in the exhaust gas and changing the amount of secondary combustion air blown only into the furnace chamber a was performed, the oxygen concentration in the exhaust gas duct could be a predetermined concentration of 1 to 2%. The exhaust gas temperature was as high as 1092 ° C. Therefore, the second step of measuring the temperature in the exhaust gas duct and changing the amount of secondary combustion air in the furnace chamber b is executed, and when the first and second steps are further repeated, in a short time of about 10 minutes. The oxygen concentration in the exhaust gas duct was predetermined 1 to 2%, and the temperature was stabilized at the target 980 to 1020 ° C. in most cases.
図５は、炉室ａ、炉室ｂ、炉室ｃ、それぞれに燃料と燃焼用空気を反応させるバーナーを有して炉室温度をそれぞれ所定の温度９５０℃、１０００℃、１０５０℃になるように制御した例である。炉室ａ及び炉室ｂは炉室内還元雰囲気を燃焼させる２次燃焼空気を供給できる。炉室ｃから炉室ｂに移動する炉室内ガスは炉室ｂで発生する被処理物から発生する還元ガスと加熱バーナー排ガスと混合して炉室ｂ内ガスとなる。更に炉室ａでも炉室ｂと同様の反応となり炉室ａ内ガスとなり排ガス処理の誘引ブロワーなどにより吸引されて排気ガスとなり排気ダクトに移動する。 FIG. 5 shows that the furnace chamber a, the furnace chamber b, and the furnace chamber c each have a burner for reacting fuel and combustion air so that the furnace chamber temperatures become predetermined temperatures 950 ° C., 1000 ° C., and 1050 ° C., respectively. This is an example of control. The furnace chamber a and the furnace chamber b can supply secondary combustion air for burning the reducing atmosphere in the furnace chamber. The furnace chamber gas that moves from the furnace chamber c to the furnace chamber b is mixed with the reducing gas generated from the object to be processed generated in the furnace chamber b and the exhaust gas from the heating burner to become the gas in the furnace chamber b. Further, the reaction in the furnace chamber a is the same as that in the furnace chamber b, becomes the gas in the furnace chamber a, is sucked in by an exhaust blower induction blower, etc., becomes exhaust gas, and moves to the exhaust duct.
本発明を適用する前は排ガス中の酸素濃度が０％で、ＣＯを２％程度検出していた。排ガス中の酸素濃度を測定して炉室ａのみの２次燃焼空気の吹き込み量を変更する第一の工程を実行したところ排ガスダクト中の酸素濃度は所定の濃度１〜２％にできたが排ガス温度が１０８５℃とやはり高くなった。そこで更に排ガスダクト中の温度を測定し炉室ｂの２次燃焼空気量も変更する第ニの工程を実行したところ、約５分という短時間で、排ガスダクト中の酸素濃度は所定の１〜２％、温度は目標の９８０〜１０２０℃となった。 Before the application of the present invention, the oxygen concentration in the exhaust gas was 0%, and CO was detected at about 2%. When the first step of measuring the oxygen concentration in the exhaust gas and changing the amount of secondary combustion air blown only into the furnace chamber a was performed, the oxygen concentration in the exhaust gas duct could be a predetermined concentration of 1 to 2%. The exhaust gas temperature was still as high as 1085 ° C. Therefore, when the second step of measuring the temperature in the exhaust gas duct and changing the amount of secondary combustion air in the furnace chamber b was performed, the oxygen concentration in the exhaust gas duct was set to a predetermined 1 to 2 in a short time of about 5 minutes. The target temperature was 980 to 1020 ° C. at 2%.
図６は、排気ガス中の酸素濃度と温度を制御する手段として実施例２における２次燃焼空気の代わりに、炉室ａ、炉室ｂの燃料燃焼用空気の量を燃料量一定の下で調整するようにしたものである。炉室ａ、炉室ｂ、炉室ｃ、それぞれ所定の温度９５０℃、１０００℃、１０５０℃になるようにし制御した。本発明を適用する前は排ガス中の酸素濃度が０％で、ＣＯを２％程度検出していた。排ガス中の酸素濃度を測定して炉室ａの燃焼空気の吹き込み量を変更する第一の工程を実行し、更に排ガスダクト中の温度を測定し炉室ｂの燃焼空気量も変更する第ニの工程を実行したところ、約７分という短時間で、排ガスダクト中の酸素濃度は所定の１〜２％、温度は目標の９８０〜１０２０℃となった。
FIG. 6 shows that the amount of fuel combustion air in the furnace chamber a and the furnace chamber b is constant under the amount of fuel instead of the secondary combustion air in the
図７は、排気ダクトの位置を炉室端部に設置するのではなく炉室全体の中間部に設置した場合である。炉室０は所定温度９００℃に制御し被処理物の乾燥予熱に用いている。バーナー６４は空気比１．０５にて燃料を完全燃焼させ十分な発熱を得ている。炉室０排ガスの余剰酸素約１％と炉室ａ排ガスの未燃ガスが排気ダクト内で反応し不必要な発熱や圧力上昇を起こさないように排気ダクトには仕切壁６１を設け統合排気ダクトで混合する前に炉室ａ排ガスの酸素濃度と温度を測定し所定の酸素濃度と温度になるよう制御した例である。炉室ａ、炉室ｂ、炉室ｃ、それぞれ所定の温度９５０℃、１０００℃、１０５０℃になるように制御した。
FIG. 7 shows a case where the position of the exhaust duct is not installed at the end of the furnace chamber but at the middle portion of the entire furnace chamber. The furnace chamber 0 is controlled to a predetermined temperature of 900 ° C. and is used for drying preheating of the object to be processed. The
本発明を適用する前は、排ガス中の酸素濃度が０〜１％で、一酸化炭素を０〜３％程度検出していた。本発明の第一の工程、第二の工程、第三の工程、第四の工程の適用に加えて排気ダクトに仕切壁６１を設け統合排気ダクトで混合する前に炉室ａ排ガスの酸素濃度と温度を測定し所定の酸素濃度と温度になるよう制御したところ、約８分という短時間で、炉室ａ排ガス中の酸素濃度は所定の１〜２％、温度は目標の９８０〜１０２０℃となった。
Before applying the present invention, the oxygen concentration in the exhaust gas was 0 to 1%, and carbon monoxide was detected about 0 to 3%. In addition to the application of the first step, the second step, the third step, and the fourth step of the present invention, the
１…造粒被処理物
２…回転炉床炉
３…炉床
４…被処理物装入設備
５…被処理物排出設備
６…加熱用バーナー(総称)
７…炉床回転方向
８…炉内雰囲気ガス流れ方向
11…排気ガス
12…炉室ａ加熱用バーナー
13…炉室ｂ加熱用バーナー
14…炉室ｃ加熱用バーナー
15…炉室ａ加熱用バーナーへの燃料制御調節弁
16…炉室ｂ加熱用バーナーへの燃料制御調節弁
17…炉室ｃ加熱用バーナーへの燃料制御調節弁
18…炉室ａ加熱用バーナーへの１次燃焼用空気制御調節弁
19…炉室ｂ加熱用バーナーへの１次燃焼用空気制御調節弁
20…炉室ｃ加熱用バーナーへの１次燃焼用空気制御調節弁
21…炉室ａ内温度検出器
22…炉室ｂ内温度検出器
23…炉室ｃ内温度検出器
24…炉室ａの２次燃焼用空気バーナー
25…炉室ｂの２次燃焼用空気バーナー
26…炉室ａの２次燃焼用空気バーナーへの空気制御調節弁
27…炉室ｂの２次燃焼用空気バーナーへの空気制御調節弁
28…排気ダクト内酸素検出器
29…排気ダクト内温度検出器
30…排気ダクト
31…炉室ａ内で発生する還元ガス
32…炉室ｂ内で発生する還元ガス
33…炉室ｃから炉室ｂへ移動する炉室ｃ内ガス
34…炉室ｂから炉室ａへ移動する炉室ｂ内ガス
35…炉室ａ
36…炉室ｂ
37…炉室ｃ
38…炉室０（乾燥予熱炉）
51…炉室ａ加熱用電気ヒーター
52…炉室ｂ加熱用電気ヒーター
53…炉室ｃ加熱用電気ヒーター
61…仕切壁
62…炉室０用排気ダクト
63…統合排気ダクト
64…炉室０加熱用バーナー
65…炉室０加熱用バーナーへの燃料制御調節弁
66…炉室０加熱用バーナーへの１次燃焼用空気制御調節弁
67…炉室０内温度検出器
68…炉室０内で発生するガス（水蒸気他）
DESCRIPTION OF SYMBOLS 1 ... Granulation to-
7 ... hearth rotation direction 8 ... atmosphere gas flow direction in the furnace
11 ... Exhaust gas
12 ... Burner for heating furnace chamber a
13 ... Furnace chamber b heating burner
14 ... Furnace chamber c heating burner
15 ... Fuel control valve to the furnace chamber a heating burner
16 ... Fuel control valve to the furnace chamber b heating burner
17 ... Fuel control valve for furnace chamber heating burner
18 ... Air combustion control valve for primary combustion to the furnace chamber a heating burner
19 ... Air combustion control valve for primary combustion to furnace chamber b heating burner
20 ... Air combustion control valve for primary combustion to furnace chamber c heating burner
21 ... Furnace chamber a temperature detector
22 ... Temperature detector in furnace chamber b
23 ... Temperature detector in furnace chamber c
24 ... Secondary combustion air burner for furnace chamber a
25 ... Air burner for secondary combustion in furnace chamber b
26 ... Air control valve for secondary combustion air burner in furnace chamber a
27 ... Air control valve for secondary combustion air burner in furnace chamber b
28 ... Oxygen detector in exhaust duct
29… Exhaust duct temperature detector
30 ... Exhaust duct
31 ... Reducing gas generated in the furnace chamber a
32 ... Reducing gas generated in the furnace chamber b
33 ... Gas in furnace chamber c moving from furnace chamber c to furnace chamber b
34 ... Gas in furnace chamber b moving from furnace chamber b to furnace chamber a
35 ... Furnace chamber a
36 ... Furnace room b
37 ... Furnace chamber c
38 ... Furnace room 0 (dry preheating furnace)
51 ... Electric heater for heating furnace chamber a
52 ... Electric heater for heating furnace chamber b
53 ... Electric heater for heating furnace chamber c
61 ... Partition wall
62 ... Exhaust duct for furnace chamber 0
63 ... Integrated exhaust duct
64 ... Burner 0 heating burner
65 ... Fuel control valve for furnace chamber 0 heating burner
66 ... Air combustion control valve for primary combustion to furnace chamber 0 heating burner
67 ... Furnace chamber 0 temperature detector
68 ... Gas generated in furnace chamber 0 (water vapor, etc.)
Claims (3)
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2004118918A JP2005300068A (en) | 2004-04-14 | 2004-04-14 | Method for control of oxygen concentration and temperature of exhaust gas from rotary hearth reducing furnace |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2004118918A JP2005300068A (en) | 2004-04-14 | 2004-04-14 | Method for control of oxygen concentration and temperature of exhaust gas from rotary hearth reducing furnace |
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| Publication Number | Publication Date |
|---|---|
| JP2005300068A true JP2005300068A (en) | 2005-10-27 |
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|---|---|---|---|
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| Country | Link |
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2007246957A (en) * | 2006-03-14 | 2007-09-27 | Jfe Steel Kk | Method for producing reduced metal |
| CN102207354A (en) * | 2011-06-22 | 2011-10-05 | 武汉北湖胜达制铁有限公司 | Novel energy-saving combustion device based on tunnel kiln reducing process |
| CN104913633A (en) * | 2015-05-28 | 2015-09-16 | 丁海涛 | Biomass fuel furnace for brightness |
| JP2017052995A (en) * | 2015-09-08 | 2017-03-16 | 住友金属鉱山株式会社 | Smelting method of nickel oxide ore |
-
2004
- 2004-04-14 JP JP2004118918A patent/JP2005300068A/en not_active Withdrawn
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2007246957A (en) * | 2006-03-14 | 2007-09-27 | Jfe Steel Kk | Method for producing reduced metal |
| CN102207354A (en) * | 2011-06-22 | 2011-10-05 | 武汉北湖胜达制铁有限公司 | Novel energy-saving combustion device based on tunnel kiln reducing process |
| CN104913633A (en) * | 2015-05-28 | 2015-09-16 | 丁海涛 | Biomass fuel furnace for brightness |
| CN104913633B (en) * | 2015-05-28 | 2017-06-20 | 奉化市精翔热处理设备厂 | A kind of biomass fuel furnace for brightness |
| JP2017052995A (en) * | 2015-09-08 | 2017-03-16 | 住友金属鉱山株式会社 | Smelting method of nickel oxide ore |
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