JPH09194915A - Combustion burner used for metallurgical furnace - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently burn bulky solid fuel of synthetic resin material, etc., supplied from a tuyere part of a metallurgical furnace and further, to suitably burn the bulky solid fuel, too while burning powdery and granular solid fuel such as pulverized fine coal, etc., at high efficiency in a melting furnace for iron-making. SOLUTION: In a combustion burner A arranged in the tuyere part B at the lower part of a shaft furnace, a pre-combustion chamber 1 is disposed inside a top opening hole part 2 and also, a charging hole for charging the bulky solid fuel into the pre-combustion chamber 1 is formed. This combustion burner has a structure having oxygen blowing holes (a) inside the pre-combustion chamber or a solid fuel injection hole arranged at the center of the burner diameter direction or this neighborhood thereof and the oxygen blowing holes (a) arranged at the surrounding thereof or the oxygen blowing hole (a) arranged at the center of the burner diameter direction or neighborhood thereof and the solid fuel injecting hole arranged at the surrounding thereof and further, the oxygen blowing holes (a) arranged at the surrounding of the solid fuel injecting hole. The bulky solid fuel is quickly burned at the high efficiency with the supplied oxygen in the pre-combustion chamber 1 and gasified by burning.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a combustion burner provided at a tuyere of a metallurgical furnace such as a melting furnace for iron making.
In particular, the present invention relates to a combustion burner suitable for using a massive synthetic resin material as fuel.

[0002]

2. Description of the Related Art In recent years, synthetic resins such as plastics have rapidly increased as industrial wastes and general wastes, and their disposal has become a major problem. Among these, plastics, which are high-molecular hydrocarbon compounds, generate a large amount of heat during combustion, and when incinerated, damage to the incinerator makes mass treatment difficult, and most of them are dumped in landfills. That is the current situation. However, dumping of plastics and the like is not preferable in terms of environmental measures, and development of a large-scale treatment method is eagerly desired.

By the way, plastics, which account for the majority of synthetic resins as waste, have a calorific value of around 10,000 cal / kg and are considered to be promising as a fuel for metallurgical furnaces such as melting furnaces for iron making. However, the inflammability of the synthetic resin material in the furnace has a strong correlation with the particle size, and the lumpy material has inferior inflammability, so that it cannot be used as a fuel simply by charging it in the furnace. Therefore, for example, when a synthetic resin material is used as an auxiliary fuel for a blast furnace or the like, as shown in JP-B-51-3349, the synthetic resin material is pulverized into powder and then blown into the furnace. I have no choice but to take. However, crushing the synthetic resin material into powder particles in this way causes an increase in processing cost, and the purpose of processing a large amount of waste synthetic resins at low cost cannot be achieved. In particular, Japanese Examined Patent Publication No. 51-3349
In the publication, hot air is blown when the synthetic resin material is blown, so the particle size of the applicable synthetic resin material is limited to about 1 mm, and it takes a lot of time and labor to pulverize to such particle size. There will be a cost.

On the other hand, in recent years, in the operation of smelting furnaces for iron making such as blast furnaces, it has been attempted to reduce the fuel cost by blowing tuyere of pulverized coal as a part of the heat source. When blowing the tuyere of charcoal, if pulverized coal is burned as efficiently as possible, and if a part of the pulverized coal can be replaced with waste synthetic resin material, or lump-shaped synthetic resin material that is not crushed, fuel cost Can be further reduced.

Further, in recent years, the supply of scraps (pigs and iron scraps) has been increasing, and their recycling is becoming an important issue in terms of effective use of resources. For this reason, there is a strong demand for the development of technology capable of producing hot metal at low cost and with high productivity from scrap as a raw material. Under such a background, the present inventors can not only efficiently produce scrap and produce hot metal, but also can produce a large amount of high-calorie exhaust gas with high utility value as a fuel gas, and Considering the utility value of calorie exhaust gas, we have developed a completely new type of scrap melting method that can be operated at a considerably lower manufacturing cost than the conventional technology.

This scrap melting method is operated under a high fuel ratio and a high pulverized coal ratio by blowing a large amount of pulverized coal.
Oxygen (substantially pure oxygen) is blown together with the pulverized coal through the combustion burner at the tuyere, the pulverized coal and oxygen are brought into contact with each other quickly and mixed to burn the pulverized coal rapidly, and the situation inside the furnace is also affected. It is characterized by adopting a means of realizing stable and highly efficient combustion of pulverized coal without causing the combustion gas of combustion of the pulverized coal to be significantly secondarily combusted in the furnace. In such a scrap melting method, it is necessary to use a pulverized coal combustion burner excellent in combustibility and combustion stability of pulverized coal in order to ensure stable and highly efficient combustion of pulverized coal, which is the above item. There is.
Also, as a partial replacement for pulverized coal, synthetic resin material that is waste,
In particular, if the lumpy synthetic resin material can be supplied, the manufacturing cost can be further reduced, and for this purpose, it is necessary to use a combustion burner that can appropriately burn the lumpy synthetic resin material.

Conventionally, as a pulverized coal combustion burner for a so-called oxygen blast furnace, it has a structure in which a pulverized coal pipe is arranged at the center and an oxygen pipe is arranged around the burner, and the pulverized coal pipe and the oxygen pipe are fed into the furnace. A burner is known in which pulverized coal is burned at the tip of the tuyere by directly blowing. However, even if this pulverized coal combustion burner is applied to the scrap melting method as described above, the combustion rate of pulverized coal varies greatly depending on the conditions of the charge (for example, coke packed bed) in the combustion space at the tuyere. , It is difficult to secure a high level of burning rate stably. Further, even if a lumpy synthetic resin material is blown from the pulverized coal pipe of the burner, the oxygen blown in at the same time is not effectively consumed for the combustion of the synthetic resin material, so that the lumpy synthetic resin material cannot be properly burned.

[0008]

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to efficiently combust solid fuel such as synthetic resin material supplied from tuyere of a metallurgical furnace even if the fuel is massive. It is to provide a combustion burner that can be used as fuel. Further, another object of the present invention is to burn powdery solid fuel such as pulverized coal with high efficiency in a melting furnace for iron making, and also to appropriately use solid solid fuel such as synthetic resin material supplied together with the powdery solid fuel. Provided is a combustion burner capable of burning, particularly a combustion burner capable of stably and efficiently burning pulverized coal in a melting furnace used for the above-described scrap melting method without being affected by conditions inside the furnace. Especially.

[0009]

In order to achieve such an object, the combustion burner of the present invention has the following structure. [1] A combustion burner provided at the tuyere of the lower part of a shaft furnace, the combustion burner having a pre-combustion chamber inside the tip opening, and charging solid lump fuel into the pre-combustion chamber. A combustion burner used in a metallurgical furnace, which has a charging port for heating and has an oxygen outlet inside the pre-combustion chamber. [2] A combustion burner provided at the tuyere of the lower part of the shaft furnace, wherein the combustion burner has a pre-combustion chamber inside the tip opening, and the solid solid fuel is charged into the pre-combustion chamber. And a solid fuel blowout hole arranged at or near the center of the burner radial direction, and an oxygen blowout hole arranged around the solid fuel blowout hole.
Combustion burner used in metallurgical furnaces.

[3] A combustion burner provided at the tuyere of the lower part of a shaft furnace, wherein the combustion burner has a pre-combustion chamber inside the tip opening, and the solid solid fuel is present in the pre-combustion chamber. Has a charging port for charging, the inside of the pre-combustion chamber, oxygen blowout hole arranged in the radial center of the burner or in the vicinity thereof, and a solid fuel blowout hole arranged around it,
Further, it has an oxygen outlet hole arranged around it,
Combustion burner used in metallurgical furnaces. [4] The combustion burner used in a metallurgical furnace according to any one of the above [1] to [3], wherein the burner axis has an inclination angle θ such that the tip end side of the burner is downward with respect to the horizontal direction. [5] In the combustion burner according to the above [1] to [4], the solid fuel blow-out hole and the oxygen blow-out hole are located near the tip exit of the pre-combustion chamber or inside the burner at the intersection of the hole axis extension lines of the two. Combustion burner used in a metallurgical furnace configured to be located.

[0011]

1 to 3 show different embodiments of the present invention. The combustion burner A shown in FIG. 1 is provided at a tuyere B at the lower part of a shaft furnace constituting a metallurgical furnace such as a melting furnace for iron making, and has a pre-combustion chamber 1 inside the tip opening 2 thereof, and the pre-combustion. The chamber 1 has a charging port 3 for charging a solid solid fuel such as a solid synthetic resin material,
Further, the pre-combustion chamber 1 has an oxygen outlet hole a inside. The combustion burner A shown in FIG. 2 is provided at a tuyere B at the lower part of a shaft furnace that constitutes a metallurgical furnace such as a melting furnace for iron making, and has a pre-combustion chamber 1 inside the tip opening 2 and the pre-combustion. The chamber 1 has a charging port 3 for charging a lumped solid fuel such as a lumped synthetic resin material, and further, a solid fuel blown out inside the pre-combustion chamber 1 at or near the radial center of the burner. It has a hole b and an oxygen outlet hole a arranged around the hole b.

A combustion burner A shown in FIG. 3 is provided at a tuyere B at the bottom of a shaft furnace which constitutes a metallurgical furnace such as a melting furnace for iron making.
The pre-combustion chamber 1 is provided inside the tip opening 2, and the pre-combustion chamber 1 also has a charging port 3 for charging a lump solid fuel such as a lump synthetic resin material. An oxygen blowout hole a'disposed inside or in the vicinity of the radial direction of the burner inside the chamber 1, a solid fuel blowout hole b arranged around it, and an oxygen blowout hole a arranged further around it. Have As shown in FIGS. 2 and 3, the combustion burner of the present invention preferably has an inclination θ so that the burner axis line is downward with respect to the horizontal direction. Further, the oxygen blowing holes a and a'and the solid fuel blowing hole b are configured such that the intersection point p of the hole axis extension lines of the two is located near the tip exit of the pre-combustion chamber 1 or inside the burner than that. It is preferable.

In the combustion burner shown in FIG. 1, the number, shape and arrangement of the oxygen blowing holes a are arbitrary. In the combustion burner shown in FIG. 2, the oxygen outlet holes a may be provided in an annular shape around the solid fuel outlet holes b, or a plurality of oxygen outlet holes a may be provided around the solid fuel outlet holes b at appropriate intervals. You may do it. FIG. 4 and FIG. 5 show an example of the arrangement of the oxygen outlets a and the solid fuel outlets b in such a burner radial direction. Further, the position of the solid fuel blowout hole b may be deviated to some extent from the center of the burner radial direction, that is, the powdery solid fuel such as pulverized coal is blown out from the burner radial center or in the vicinity thereof, and its surroundings. Oxygen should be blown out from the.

Further, in the combustion burner of FIG. 3, the solid fuel blowout hole b may be provided so as to annularly surround the oxygen blowout hole a'disposed at or near the radial center of the burner, or oxygen. A plurality of solid fuel outlets b may be arranged around the outlet a'at appropriate intervals.
Also, the oxygen outlet holes a provided around the solid fuel outlet holes b may be annularly provided around the solid fuel outlet holes b, or a plurality of oxygen outlet holes a may be provided around the solid fuel outlet holes b at appropriate intervals. The oxygen outlet a may be provided.
6 to 8 show an example of the arrangement of the oxygen outlet holes a and the solid fuel outlet holes b in such a burner radial direction.
The position of the oxygen outlet hole a'may be deviated to some extent from the center of the burner radial direction. In short, oxygen is blown out from the center of the burner radial direction or in the vicinity thereof, and powder dust such as pulverized coal is generated from the periphery thereof. The solid fuel may be blown out and oxygen may be blown out from the surroundings.

The operation of each combustion burner will be described below with reference to the case where a lump synthetic resin material is used as the lump solid fuel and pulverized coal is used as the powdery solid fuel.
In the combustion burner shown in FIG. 1, a bulk synthetic resin material is charged into the pre-combustion chamber 1 through the charging port 3, and oxygen (O ₂ ) is blown through the oxygen blowing hole a. At this time, since the oxygen supplied to the pre-combustion chamber 1 is effectively used for the combustion of the synthetic resin material, even the lumpy synthetic resin material is rapidly and efficiently burned and converted into combustion gas. This combustion gas is introduced into the furnace through the burner tip opening 2.

In the combustion burner shown in FIG. 2, a lumped synthetic resin material is charged into the pre-combustion chamber 1 through the charging port 3, and the solid fuel blowout hole b is arranged at or near the radial center of the burner. Pulverized coal (PC) and oxygen (O ₂ ) are respectively blown from the oxygen blowing holes a provided around the pulverized coal (PC). At this time, as described above, the lumpy synthetic resin material burns with high efficiency, and since the pulverized coal is blown so as to be surrounded by oxygen, the contact between the pulverized coal and oxygen becomes extremely good, and both are The pulverized coal is rapidly mixed in the pre-combustion chamber 1 and rapidly ignited and burned. Therefore, even if a large amount of pulverized coal is blown in per unit amount of oxygen, the pulverized coal burns with high efficiency, and most of the pulverized coal is burnt and gasified in the pre-combustion chamber 1,
This combustion gas is introduced into the furnace through the burner tip opening 2 together with the combustion gas of the synthetic resin material. Since the pulverized coal is highly efficiently combusted and gasified in this manner, a large amount of pulverized coal is blown in, and the pulverized coal ratio PC (kg / t · pig) and the oxygen supply amount (N
The ratio [m ³ / t · pig] [PC / O ₂ ] can be made sufficiently high.

Further, in the combustion burner shown in FIG. 3, the bulk synthetic resin material is charged into the pre-combustion chamber 1 through the charging port 3, and the oxygen blowing hole a is arranged at or near the radial center of the burner. 'is oxygen (O ₂₎ from the pulverized coal from the pulverized coal outlet hole b disposed therearound (PC) is, oxygen (O ₂₎ is blown from each of more oxygen outlet hole a of the disposed around. Therefore, the pulverized coal (PC) is pre-combusted in the pre-combustion chamber 1 so that the inside and the outside of the pulverized coal are signed by oxygen (O ₂ ) blown out from the oxygen blowing holes a and a '.
Since it is blown into the inside, the contact and mixing of the pulverized coal and oxygen are further promoted, and the combustion efficiency of the pulverized coal is further enhanced. In the combustion burner of the present invention shown in FIGS. 2 and 3, charging of the lumped synthetic resin material from the charging port 3 and blowing of pulverized coal from the solid fuel blowing hole b are selectively performed. Good.

In the pre-combustion chamber 1, the ash content in the pulverized coal is melted to generate slag, but as shown in FIGS. 2 and 3, an inclination angle θ is added to the axis of the combustion burner so that the burner tip side is directed downward. By doing so, the slag will be burner tip opening 2
Does not impair the burner's combustion performance. Further, as shown in FIGS. 2 and 3, the intersection p of the hole axis extension lines of the oxygen outlets a, a ′ of the combustion burner and the solid fuel outlet b is located at the tip exit of the pre-combustion chamber 1 or inside the burner than that. When the structure is located on one side, the mixing of the pulverized coal and oxygen in the pre-combustion chamber 1 becomes faster, and the rapid ignition and combustion of the pulverized coal can be realized more reliably.

In order to ignite and burn the pulverized coal and the synthetic resin material charged or blown into the pre-combustion chamber 1, an ignition burner (not shown) using oil, LPG or the like as fuel can be used at all times. In addition, the inner wall of the pre-combustion chamber 1 is made of refractory, and only in the initial stage of operation, an ignition burner (pilot burner) is used to preheat the interior of the burner or to ignite and burn the synthetic resin material and pulverized coal. It is also possible to spontaneously ignite the synthetic resin material and the pulverized coal by the radiant heat of the red-heated refractory material.

As described above, according to the combustion burner of the present invention, the massive synthetic resin material can be efficiently burned, and the pulverized coal blown in a large amount in the furnace can be burned with high efficiency and stability. be able to. In contrast, FIG.
When the bulk synthetic resin material and the pulverized coal are blown by the known lance method as shown in Fig. 1, it is not possible to secure a sufficient amount of oxygen for burning the bulk synthetic resin material at the tuyere tip, and Since the contact between the pulverized coal and the pulverized coal is not sufficiently secured, the pulverized coal cannot be burned with high efficiency. FIG.
Even if a lumpy synthetic resin material and pulverized coal are burned from the center of the burner using a combustion burner that does not have a pre-combustion chamber as shown in Fig. 0, and oxygen is blown into the furnace from the surroundings and burned at the tuyere tip, A sufficient amount of oxygen for burning the lumpy synthetic resin material cannot be secured at the tip of the mouth, the combustion efficiency of pulverized coal is inferior to that of the combustion burner of the present invention, and the stability of combustion efficiency is lacking.

FIG. 9 shows the relationship between the average particle size of the synthetic resin material supplied to the burner and the combustibility of the combustion burner of the present invention and the combustion burner having no pre-combustion chamber shown in FIG. The results shown in FIG. 9 are obtained by attaching each combustion burner to the tuyere of the shaft furnace for melting scrap, blowing the synthetic resin material, and evaluating the combustibility of the synthetic resin material by the following coke substitution rate R. . Coke substitution rate R = A / B where A: coke ratio reduced by blowing synthetic resin material (kg / t · pig); B: blowing ratio of synthetic resin material (kg / t · pig); calculation of A Method: CR is the coke ratio during the synthetic resin blowing operation, PCR is the pulverized coal ratio during the synthetic resin blowing operation, and the pulverized coal ratio is 80% of the coke.
A (kg / by the following equation substituted by the ratio of “A = (fuel ratio during all coke operation) −CR−0.8 × PCR”]
t · pig) is calculated.

According to FIG. 9, in the combustion burner shown in FIG. 20, when the average particle size of the synthetic resin material is 2 to 3 mm or more, the coke replacement rate begins to decrease, and when the average particle size is 7 mm or more, the coke replacement rate becomes. It breaks 80%. On the other hand, in the combustion burner of the present invention, the average particle size of the synthetic resin material is 2
If it is 5 mm or less, a burning rate of about 100% is obtained. Although there is no particular limitation on the particle size of the bulk synthetic resin material that can be supplied to the combustion burner of the present invention, as shown in FIG. 9, a synthetic resin material having an average particle size of 25 mm or less is supplied from the viewpoint of flammability. Preferably. Although there is no lower limit to the particle size of the synthetic resin material in relation to the burning rate, in consideration of the pretreatment cost of the synthetic resin material and the like, it is preferable to use a lumpy synthetic resin material having an average particle size of 10 mm or more. It is advantageous.

Next, with respect to the combustion burner of the present invention shown in FIGS. 2 and 3, the function and effect of pulverized coal combustibility will be described. FIG. 10 shows a case where pulverized coal is rapidly burned by the combustion burner of the present invention shown in FIG. 2 at the tuyere of a scrap melting furnace (example of the present invention), and a combustion burner shown in FIG. 20 having no pre-combustion chamber. When the pulverized coal was rapidly burned at the tuyere tip (Comparative Example), the burning rate of the pulverized coal was examined over time (all were [PC / O ₂ ] = 1.2 k
g / Nm ³ ). According to this, even in the case of the comparative example, although the pulverized coal combustion rate temporarily reaches a high level of about 90%, the combustion rate fluctuates greatly over time, and the high-level combustion rate is stably maintained. Difficult to do. This is the charge in the combustion space at the tuyere (for example,
It is considered that the situation such as coke packed bed) fluctuates, which affects the combustibility of pulverized coal.

On the other hand, in the case of the combustion burner of the present invention shown in FIG. 2, most of the supplied pulverized coal is combusted and gasified in the pre-combustion chamber, so that the combustion of the pulverized coal depends on the condition inside the furnace. It is almost unaffected and, as a result, a high level of pulverized coal combustion rate is stably obtained. According to the combustion burner of the present invention,
The combustion limit of [PC / O ₂ ] is almost stoichiometric [P
Even if pulverized coal is blown up to about C / O ₂ ] = 1.4 kg / Nm ^2, most of the pulverized coal is combusted and gasified in the pre-combustion chamber,
In addition, even if there is some unburned pulverized coal, it burns rapidly at the tuyere.

FIG. 11 shows a case where pulverized coal is rapidly burned using the combustion burner of the present invention shown in FIG. 2 (example of the present invention),
FIG. 20 shows ideal combustion conditions in the vicinity of each tuyere when pulverized coal was rapidly burned at the tuyere tip using a combustion burner without a pre-combustion chamber (comparative example). is there. According to this, in the combustion burner of the comparative example, a combustion zone is formed at the tuyere and a so-called raceway is formed outside thereof. On the other hand, in the ideal state of the combustion burner of the present invention, almost all the amount of oxygen blown into the pre-combustion chamber 1 is rapidly consumed in the pre-combustion chamber 1, and as a result,
Although the furnace CO ₂ is generated in the combustion gas (the combustion burner of the pulverized coal, CO ₂ in the combustion gas introduced into the furnace
Is very small and most are CO). As a result, almost no combustion zone (oxidation zone) like the combustion burner of the comparative example is formed at the tuyere, and only the raceway is formed.

The purity of the oxygen gas used in the combustion burner of the present invention is preferably as high as possible, but the purity of the oxygen gas generally used for industrial purposes is 99% or more (generally sold on the market). The purity of industrial oxygen gas is about 9
It is about 9.8% to 99.9%, and the purity of oxygen gas obtained from an oxygen plant of a steel mill is about 99.5%), and a purity of this level is sufficient. Further, from the viewpoint of the action and effect, since the combustibility of the lump synthetic resin material and the contact between the pulverized coal and oxygen cannot be sufficiently secured with oxygen gas having a purity of less than 95%, the combustion of the lump synthetic resin material and the pulverized coal is not possible. Inefficient. Therefore, the oxygen blown from the oxygen blowing holes a in the combustion burner of the present invention means oxygen gas having a purity of 95% or more. Further, although there is no particular restriction on the particle size of the pulverized coal to be blown, for example, pulverized coal having a particle size of 74 μm or less in an amount of 80% or more is suitable.

The basic operation of the combustion burner of the present invention has been described above by taking the case of using the lump synthetic resin material as the lump solid fuel and the pulverized coal as the pulverized solid fuel as an example. Needless to say that the solid fuel is not limited to these, and for example, as the powdery solid fuel, a powdery or strip-like synthetic resin material can be used alone or in combination with pulverized coal. Further, the combustion burner of the present invention can be applied to various iron melting furnaces such as blast furnaces, cupolas, scrap melting furnaces, and other metallurgical furnaces.

As described above, according to the combustion burner of the present invention, not only the massive synthetic resin material can be appropriately burned, but also a large amount of pulverized coal can be highly efficiently irrespective of fluctuations in the furnace conditions and operating conditions. It can be stably converted into combustion gas. Therefore, it can be said that the combustion burner of the present invention is particularly suitable for the scrap melting method characterized by the above-mentioned items 1 to 3. Hereinafter, the operation and usefulness of the combustion burner of the present invention when applied to this scrap melting method will be described.

First, the background to the development of the scrap melting method characterized by the above items 1 to 3 will be described. Conventionally, the electric furnace method and the cupola method have been widely used for producing hot metal and cast iron from scrap, but these methods have a major drawback of high production cost. In contrast to such conventional electric furnace method and cupola method, as a scrap melting method using a shaft furnace, the scrap that is the iron source and the blast furnace coke are charged into the shaft furnace, and at the same time from the tuyere to room temperature. Highly oxygen-enriched air and pulverized coal are blown and burned, and the sensible heat of this combustion gas melts the scrap, and by blowing air from the shaft part, the combustion gas is secondarily burned to promote the melting of scrap. A scrap melting method has been proposed (Iron and Steel Vol. 7
9, No. 2, P. 139-146).

As another method, a combustion furnace for combustion of pulverized coal is provided outside the shaft furnace, and a large amount of pulverized coal is burned in this combustion furnace, and the generated high-temperature combustion gas is charged with scrap and coke. A scrap melting method has been proposed in which the scrap is melted by sensible heat of the combustion gas by introducing oxygen-containing gas to the combustion furnace to re-combust the combustion gas during the introduction. (JP-A-1-195225). In the scrap melting method proposed by these proposals, pulverized coal can be used as a part of the heat source, and inexpensive blast furnace coke can be used as the coke to be charged into the furnace. Therefore, there is a possibility that economical operation can be realized.

However, both of the above-mentioned two scrap melting methods are technologies aiming at an energy minimum with a low fuel ratio, and therefore, operation with a low fuel ratio (fuel ratio: less than 300 kg / t · pig) is performed. In addition, oxygen-containing gas such as air is further blown into the combustion gas generated by the combustion of pulverized coal for secondary combustion to promote scrap melting under a low fuel ratio. That is, the purpose of these conventional scrap melting methods is to reduce the fuel ratio and to achieve the cost reduction of scrap melting by using pulverized coal as a part of the heat source. There is no intention to obtain a large amount of exhaust gas (fuel gas) by actively supplying a large amount of pulverized coal to combustion gas by supplying a large amount of fuel to operate at a high fuel ratio. It does not have the proper operating conditions or means.

Further, in these conventional scrap melting methods, pulverized coal is used as part of the heat source in order to reduce the manufacturing cost, but the supply amount is [pulverized coal ratio / coke ratio].
The weight ratio was less than 1.0 (at most about 0.9) and the fuel ratio was kept low, but the cost was sufficiently reduced in the sense that the coke ratio was relatively high. It is hard to say that In addition, in these scrap melting methods, in order to enable operation at a low fuel ratio, an oxygen-containing gas such as air is further blown into the combustion gas of pulverized coal for secondary combustion. Since air or oxygen-enriched air is used for secondary combustion,
Exhaust gas inevitably contains a large amount of nitrogen, CO _{2, and the} like. Therefore, although the exhaust gas discharged from the furnace in these conventional scrap melting methods has a certain utility value as a fuel gas, it can be used as a fuel gas for performing highly efficient power generation or a fuel gas for a heating furnace, for example. It is not a high-calorie gas with a large amount of heat.

For example, in the former document describing the prior art (Iron and Steel Vol.79, No.2, P.139-146), exhaust gas having a higher calorie than that of the cupola method is obtained, and this is used as fuel gas. The exhaust gas calorie is about 2000 kcal / Nm ³ (about 8400 kJ / Nm ³ ).
Only about. In addition, although data of an experimental example performed without conducting secondary combustion on a trial basis is also shown in the same literature,
According to the results calculated by the present inventors, even in this case, the calorie of the exhaust gas is no more than about 2300 kcal / Nm ³ . Generally, a high-calorie gas of 2500 kcal / Nm ³ or more is used as a fuel gas for a heating furnace or high-efficiency power generation. Therefore, the exhaust gas obtained by the conventional technique is suitable for a heating furnace or high-efficiency power generation. In other words, it must be said that it has low utility value. Further, since the operation is performed at a low fuel ratio, the amount of exhaust gas generated is small, and the calorie of exhaust gas is low, which is not a technology capable of stably supplying a large amount of high-quality fuel gas.

The latter prior art (Japanese Patent Laid-Open No. 1-195)
No. 225) requires a combustion furnace for combustion of pulverized coal in addition to the melting furnace, and the facility cost is high, and the sensible heat of gas is generated while the high temperature gas generated in the combustion furnace is introduced into the shaft furnace by the gas conduit. There is also a problem in terms of economy because some of the As described above, since the scrap melting technology that has been conventionally proposed is basically aimed at the energy minimum by reducing the fuel ratio, the exhaust gas has low heat quantity and low emission quantity, and is of low utility value. there were. Also, although pulverized coal is used as part of the heat source, it is not possible to achieve highly efficient combustion of pulverized coal, so the pulverized coal ratio cannot be sufficiently increased with respect to the coke ratio,
Cost reduction has not been sufficiently achieved by using pulverized coal.

The scrap melting method having the above-mentioned characteristics (1) to (3) not only efficiently melts scrap under such a background to produce hot metal, but also has a high calorific value which is highly useful as a combustion gas. It was developed for the purpose of positively obtaining exhaust gas, and a combustion burner was installed at the tuyere under operating conditions where the fuel ratio was increased by supplying a large amount of pulverized coal and the pulverized coal ratio was increased relative to the coke ratio. Scrap and coke (usually
Blast furnace coke) is charged, and the pulverized coal blown through the combustion burner at the tuyere is efficiently contacted with oxygen to rapidly burn the pulverized coal and the combustion gas is introduced into the furnace to produce combustion gas. The sensible heat of melts the scrap to produce hot metal, and the combustion gas does not significantly burn in the furnace (that is, by supplying air or oxygen-enriched air to the shaft as in the prior art). The basic content is to recover the fuel gas as fuel gas without second combustion.

In such a scrap melting method, as shown in FIG.
And the case of using the combustion burner of the present invention shown in FIG.
As shown in Fig. 0, a large amount of pulverized coal can be efficiently and stably combusted and gasified regardless of the conditions inside the furnace or changes in operating conditions. Therefore, [PC / O ₂ ]: 0.7 kg / Nm ³ Stable operation is possible even at the above (preferably 1.0 kg / Nm ³ or more), so that a large amount of high-calorie exhaust gas can be obtained by highly efficient combustion of pulverized coal, and moreover, coke with respect to the pulverized coal ratio. It is possible to operate with a relatively low ratio. Further, since a part of the pulverized coal to be used is replaced by a lumpy synthetic resin material and this lumpy synthetic resin material can be highly efficiently combusted and gasified, a high calorie exhaust gas can be produced at a further lower cost. . Further, as shown in FIG. 11, in the combustion burner of the present invention, most of the supplied oxygen is rapidly consumed in the pre-combustion chamber, so that it is assumed that the combustion zone is hardly formed or is formed at the tuyere. Also, it is formed only in a very limited and narrow area. Therefore, the consumption (combustion) of coke at the tuyere is suppressed, which also contributes to the reduction of the coke ratio.

The gas blown into the combustion burner for combustion is oxygen (substantially pure oxygen), and a large amount of pulverized coal per unit amount of oxygen is efficiently burned without being affected by the in-furnace conditions. High-calorie gas can be obtained by burning the massive synthetic resin material that can be gasified and is charged together with pulverized coal. Furthermore, by not secondary burning the combustion gas as described above, low hydrocarbons and It is possible to obtain a high-calorie exhaust gas (2700 kcal / Nm ² or more) having an extremely high content of high-calorie gas components such as CO and H ₂ (thus having a very low content of CO ₂ and N ₂ ).

The above-mentioned scrap melting method is premised on a higher fuel ratio and a larger amount of pulverized coal injection as compared with the conventional method, but the target range is based on actual operation, fuel ratio: 300 kg. / T · pig or more, the weight ratio of the pulverized coal ratio (kg / t · pig) and the coke ratio (kg / t · pig) [pulverized coal ratio / coke ratio]: 1.0 or more, which makes the hot metal high. It is possible to efficiently manufacture and to stably supply a large amount of the high-calorie exhaust gas as described above. In addition, the upper limit of these is the operating rate,
Although it depends on the fuel cost and the required recovery gas balance, etc., it is generally considered that the fuel ratio: 500 kg / t · pig, [pulverized coal ratio / coke ratio]: about 2.5 is the practical upper limit.

Thus, in the scrap melting method described above,
Since it is premised on operating with a relatively higher fuel ratio than the conventional method, the fuel cost itself will be higher than the conventional method, but on the other hand, a large amount of pulverized coal, which is much cheaper than coke, will be produced. It is possible to reduce the coke ratio relatively by using a large amount of massive synthetic resin material, and it is possible to mass produce high-calorie exhaust gas with high utility value. It can be implemented at a significantly lower manufacturing and operating cost than the law.

Further, in the above scrap melting method, simultaneously blowing pulverized coal (and a synthetic resin material) and oxygen by using the combustion burner of the present invention is useful for ensuring the yield and quality of the hot metal. That is, assuming a method in which only coke is charged into the furnace as a heat source and only oxygen is blown from the tuyere, an oxygen band is formed long in the depth direction at the tuyere, and the hot metal flowing in the vicinity thereof is easily oxidized. Therefore, iron migrates as FeO into the slag to reduce the yield of iron, and suspends the oxide in the components of the hot metal to deteriorate the quality of the hot metal. Also,
Even when pulverized coal (and synthetic resin material) and oxygen are blown into the furnace using a combustion burner having no pre-combustion chamber as shown in FIG. 20, O ₂ is present at the tuyere tips as shown in FIG. The existing combustion zone (oxidation zone) is formed, and as a result, the molten pig iron dropping on the tuyere is oxidized.

On the other hand, when the combustion burner of the present invention is used, the pulverized coal (and the synthetic resin material) rapidly consumes oxygen in the pre-combustion chamber, so that the combustion zone is almost present at the tuyere. It is not formed, or even if it is formed, it is formed only in a very limited narrow area, so that the above-described oxidation of the molten pig iron poses almost no problem. Further, such an effect can be effectively obtained by setting [PC / O ₂ ] to 0.7 kg / Nm ³ or more, and more preferably 1.0 kg / Nm ³ or more.

By the way, in general, when a relatively large amount of synthetic resin material is supplied as fuel from the tuyere into the shaft furnace,
The following problems are conceivable. (1) If a sufficient amount of the supplied synthetic resin material does not burn rapidly at the tuyere or at the tuyere, the unburned synthetic resin material will be fused in the bed coke and the air permeability in the furnace will be significantly increased. It interferes with the operation of the shaft furnace as a result. (2) The proportion of vinyl chloride in synthetic resin materials as general waste or industrial waste is said to reach about 20%. When such a synthetic resin material is charged into the furnace, ,
A large amount of HCl is generated by the combustion of the vinyl chloride material, and this is mixed in the exhaust gas and remarkably deteriorates the quality of the fuel gas. (3) The unburned synthetic resin material is once pyrolyzed in the furnace, but these decomposed products (gas) secondarily react with each other at the furnace top or in the exhaust gas pipe system to generate a tar precursor, The tar-like substance generated by the deposition adheres to and accumulates on the inner surface of the exhaust gas pipe and blocks the pipe.

However, according to the above scrap melting method using the combustion burner of the present invention shown in FIGS. 2 and 3, (1)
It has been found that it is possible to supply synthetic resin material in the furnace without causing the problem of (3). That is, first
Regarding the point (1), a considerable amount of the synthetic resin material charged by using the combustion burner of the present invention rapidly burns in the pre-combustion chamber, and therefore the unburned synthetic resin material in the lower part of the furnace. However, the problem that the synthetic resin material is fused in the coke bed and impairs the air permeability in the furnace does not occur.

Regarding the above point (2), the HCl concentration in the exhaust gas is effectively reduced for the following reason.
First, in order to reduce the concentration of HCl in the exhaust gas, H such as CaO, Na ₂ O and Fe contained in the dust in the exhaust gas should be used.
It is most effective to let the Cl trapping component trap HCl. In the scrap melting method using the combustion burner of the present invention, since pulverized coal is burned with high efficiency and stability, even if a large amount of pulverized coal is blown, the amount of the blown coal is included in the exhaust gas. The amount of unburned char that is discharged is small, and therefore the amount of dust in the furnace top gas is also relatively small. However, since the amount of the HCl trapping component in the furnace top gas is proportional to the amount of pulverized coal blown, the amount of the HCl trapping component in the furnace top gas is relatively large in the above scrap melting method in which a large amount of pulverized coal is blown. Therefore, the HCl trapping rate by the HCl trapping component is high.

In the scrap melting method using the combustion burner of the present invention, since the combustion efficiency of pulverized coal is high, the amount of unburned char in the exhaust gas is relatively large relative to the amount of pulverized coal injected. Although small, the exhaust gas still contains a considerable amount of unburned char. The unburned char has a function of strongly adsorbing (physically adsorbing) a large amount of HCl in the exhaust gas (physical adsorption), so that the concentration of HCl in the gas is reduced by contact with the exhaust gas for a very short time. The HCl physically adsorbed on the surface of the unburned char is gradually contained in the dust.
It reacts with trapping components (CaO, Na ₂ O, Fe, etc.) and is fixed to dust. In other words, the HCl physically adsorbed on the unburned char is absorbed by the HCl trapping component due to a chemical reaction over time, and finally CaCl ₂ , N
It is fixed as a chloride such as aCl or FeCl ₂ . Then, these chlorides are separated and removed from the exhaust gas as a part of dust.

In particular, in the scrap melting method described above, since significant secondary combustion is not performed at the shaft portion or furnace top, H
There is an advantage that unburned char for adsorbing Cl is not lost through the furnace shaft and the furnace top. Therefore, the adsorption of HCl by the unburned char is effectively performed, and the HCl once adsorbed by the unburned char does not move to the gas side again. From the above mechanism for reducing HCl, in order to effectively reduce HCl in exhaust gas, it is necessary to adjust the blowing amount of the synthetic resin material (more accurately, the blowing amount of the vinyl chloride material). It is preferable that the amount of HCl trapping component and the amount of unburned char are secured, and therefore, a considerable amount of pulverized coal corresponding to the amount of synthetic resin material blown is blown. Specifically, it is preferable to blow pulverized coal with a weight that is 1/10 or more of the amount of synthetic resin material blown, and the amount (weight) of the pulverized coal blown is the amount of vinyl chloride material blown. It is preferably at least the amount.

Next, regarding the above point (3), since a relatively large amount of pulverized coal is blown from the tuyere in the scrap melting method using the combustion burner of the present invention, the furnace top gas is generally Hydrogen is contained at a concentration of 5% or more. And, since the decomposition product of the synthetic resin material is stabilized by the presence of this hydrogen, it is controlled that the decomposition products secondarily react with each other to generate the tar precursor, which causes troubles such as pipe clogging. It is possible to prevent the generation of tar-like or wax-like substances that are the cause. As described above, even if the synthetic resin material is put in the furnace in the hot metal manufacturing method, no problems are expected by the scrap melting method using the combustion burner of the present invention.

In the above scrap melting method,
The purity of oxygen gas supplied to the combustion burner of the present invention is preferably as high as possible, but as described above, the purity of oxygen gas generally used for industrial purposes is 99% or more, which is about this level. Purity is sufficient. In terms of the effects obtained by the present invention, the purity is 95%.
If the oxygen gas content is less than 10%, sufficient contact between the pulverized coal and synthetic resin material to be blown cannot be ensured, and the combustion efficiency of the pulverized coal and synthetic resin material will deteriorate, and the low-calorie gas component in the exhaust gas will also increase. It is not preferable because it will happen. Therefore, as the oxygen gas to be supplied to the combustion burner, one having a purity of 95% or more is used.

[0049]

EXAMPLE FIG. 12 and FIG. 13 show an example of a combustion burner of the present invention provided in a tuyere B of a metallurgical furnace such as a melting furnace for iron making. 4 is a furnace wall of the melting furnace. is there. In each of the following examples, a bulk synthetic resin material is used as a bulk solid fuel,
Further, a case where pulverized coal is used as the powdery solid fuel will be described as an example. The combustion burner A has a pre-combustion chamber 1 inside the burner tip opening 2 for burning a lump of synthetic resin material, and a burner main body 5 having an oxygen blowout hole a and a peep window c inside thereof. In addition, it also has a charging port 3 for charging the massive synthetic resin material into the pre-combustion chamber 1.

The burner body 5 includes a water cooling jacket 6 having a cylindrical shape, an oxygen supply pipe 7 penetrating the jacket 6, and a tube body 8 for a sight glass.
And the like, and the oxygen supply pipe 7 and the viewing window pipe body 8
The end of the open end opens to the front surface of the burner body 5 (the front surface of the water cooling jacket 6) to form an oxygen outlet hole a and a viewing window c. A pilot burner 9 for preheating the inner wall of the pre-combustion chamber 1 at the start of use of the combustion burner
However, like the oxygen supply pipe 7 and the like, it is provided so as to penetrate the water cooling jacket 5.

The pre-combustion chamber 1 is formed in a tubular shape between the burner main body 5 and the burner tip opening 2, and a non-metal refractory 10 is lined on the inner wall of the burner. During use, the refractory 10 is made to glow red, and the radiant heat ignites the fuel (synthetic resin material) supplied into the pre-combustion chamber. Further, in order to secure the gas flow velocity of the combustion gas injected into the furnace, the pre-combustion chamber 1 is configured so that the burner tip side is tapered. The charging port 3 is open to the inner wall surface of the pre-combustion chamber 1 at the front position of the burner body 5, and an inclined charging chute 11 is connected to the charging port 3.

The charging chute 11 is provided with a fixed amount cutting device 1
A lump synthetic resin material supply hopper 13 is connected via 2. Further, 14 is a storage hopper for a block of synthetic resin material, 1
Reference numeral 5 denotes a replenishment hopper interposed between the storage hopper 14 and the supply hopper 13, and the massive synthetic resin material stored in the storage hopper 14 is cut out to a replenishment hopper 15 via a cutting device 30. Replenishing hopper 15 to cutting device 3
It is cut out into the supply hopper 13 via 1. The replenishing hopper 15 and the supply hopper 13 each have an airtight structure, and a communication pipe 21 having a pressure equalizing valve 22 is connected between both hoppers. Further, the refilling hopper 15 is provided with a pressure reducing valve 23.

A gas for pressurization (N
₍₂ etc.) is connected to a gas supply pipe 16 and the gas supply pipe 16 is provided with a valve 17 having an opening degree adjuster 18. Further, 19a is a pressure gauge for measuring the pressure in the pre-combustion chamber 1, 19b is a pressure gauge for measuring the pressure in the supply hopper 13, and 20 is a differential pressure between the pressures measured by both pressure gauges 19a, 19b. It is a differential pressure detector for detecting, and the opening adjuster 18 is the differential pressure detector 2
The opening degree of the valve 17 is adjusted based on the differential pressure signal from zero. A water cooling jacket 24 for cooling the precombustion chamber is provided outside the precombustion chamber 1, and a tuyere 25 having a water cooling structure is provided at the tip of the burner. This tuyere 25
Is for protecting the burner tip from the high temperature atmosphere in the furnace, but may not be provided in some cases. In addition,
In the other drawings, 26a and 26b are pipes for supplying and draining cooling water with respect to the water cooling jacket 6, and 27a.
Is a pipe for supplying / draining cooling water with respect to the water cooling jacket 24 (however, a water distribution pipe is not shown), and 28a is a pipe for supplying / draining cooling water with respect to the tuyere 25 (however, a drain pipe is not shown). ).

14 and 15 show another embodiment of the combustion burner of the present invention provided at the tuyere B of a metallurgical furnace such as a melting furnace for iron making. The burner body constituting the combustion burner A is shown in FIGS. On the front surface of the burner 5, a solid fuel blowout hole b is arranged at or near the center of the burner radial direction, and a plurality of oxygen blowout holes a are arranged around the solid fuel blowout hole b at appropriate intervals. Each of these blow-out holes a and b is formed by the tip end opening of the oxygen supply pipe 7 and the solid fuel supply pipe 29 which penetrate the water cooling jacket 6, respectively. Further, in order to speed up the mixing of pulverized coal and oxygen in the pre-combustion chamber 1 and efficiently and rapidly combust the pulverized coal, the oxygen outlet a and the solid fuel outlet b are
The intersection point p of the extension lines of the two hole axes is arranged so as to be located at the outlet tip of the pre-combustion chamber 1 or inside the burner than that.

Further, the entire combustion burner is attached to the furnace wall 4 with its axis having an inclination angle θ such that the tip end side of the burner is downward with respect to the horizontal direction. The inclination angle θ is added in this manner in order to smoothly discharge the slag generated by melting the ash content in the pulverized coal from the burner tip opening 2 into the furnace. The inclination angle θ is set so that the tapered portion of the pre-combustion chamber 1 is horizontal or the tip side thereof is inclined downward so that the slag in the pre-combustion chamber 1 flows down smoothly toward the burner tip opening 2. It is preferable. In addition,
Other configurations are similar to those of the embodiment shown in FIGS. 12 and 13, and therefore, the same reference numerals are given and detailed description thereof is omitted.
Further, a mechanism such as a supply hopper for supplying the lumped synthetic resin material to the charging chute 11 is also similar to that of the embodiment shown in FIGS. 12 and 13, though not shown. Further, the shapes and arrangements of the oxygen outlets a and the solid fuel outlets b are not limited to the present embodiment, and various aspects such as those illustrated in FIGS. 4 and 5 described above are applicable. Can be taken.

16 and 17 show another embodiment of the combustion burner of the present invention provided at the tuyere B of a metallurgical furnace such as a melting furnace for iron making. The burner body constituting the combustion burner A is shown in FIGS. On the front surface of the burner 5, an oxygen blowout hole a'is arranged at or near the center of the burner radial direction, a plurality of solid fuel blowout holes b are arranged at appropriate intervals around the burner radial direction, and further at appropriate intervals around it. In addition, a plurality of oxygen outlets a are arranged. Each of these blow-out holes a, a ′, b is formed by an oxygen supply pipe 7, 7 ′ penetrating the water cooling jacket 6 and a tip end opening of a solid fuel supply pipe 29. In addition,
Other configurations are the same as those of the embodiments shown in FIGS. 12, 1 and 14 and 15, and therefore, the same reference numerals are given and detailed description thereof is omitted. Further, a mechanism such as a supply hopper for supplying the lumped synthetic resin material to the charging chute 11 is also similar to that of the embodiment shown in FIGS. 12 and 13, though not shown. Further, as in the embodiment shown in FIGS. 14 and 15, the shapes and arrangements of the oxygen blowing holes a and a ′ and the solid fuel blowing holes b are not limited to the present embodiment, and are described above. Various modes as illustrated in FIGS. 6 to 8 can be adopted.

In each of the embodiments described above, the charging chute 11
The lump-shaped synthetic resin material supplied through the charging port 3 is charged into the pre-combustion chamber 1 through the charging port 3, and oxygen is blown into the pre-combustion chamber 1 through the oxygen outlet holes a. The resin material burns into combustion gas, and this combustion gas is introduced into the furnace through the burner tip opening 2. In addition, in the embodiment of FIGS. 14 and 15 and the embodiment of FIGS. 16 and 17, pulverized coal is blown into the pre-combustion chamber 1 through the solid fuel ejection holes b, and this pulverized coal also rapidly flows in the pre-combustion chamber 1. Burns and turns into combustion gas. The ignition of the massive synthetic resin material in the pre-combustion chamber 1 is carried out only by the pilot burner 9 in the early stage of the operation by preheating the interior of the burner or by igniting and burning the massive synthetic resin material (and the pulverized coal), and in the subsequent steady operation, red heat is generated. The massive synthetic resin material (and pulverized coal) is spontaneously ignited by the radiant heat of the refractory material 10 thus prepared.

Next, the supply hopper 13 and the charging chute 1
A method of supplying the block-shaped synthetic resin material from No. 1 will be described.
The massive synthetic resin material in the supply hopper 13 is quantitatively supplied into the charging chute 11 by the constant amount cutting device 12, and is charged into the pre-combustion chamber 1 from the charging port 3. At this time, in order to prevent the combustion gas in the pre-combustion chamber 1 from flowing back to the supply hopper 13 side, gas such as N ₂ is supplied into the supply hopper 13 through the gas supply pipe 16 and the inside of the hopper is pressurized. It This pressure control is performed by using the pressure gauges 19a and 19b to control the pressure P in the pre-combustion chamber 1.
a and the pressure Pb in the supply hopper 13 are measured, and the differential pressure between the two is detected by the differential pressure detector 20, and this differential pressure (Pb-Pa) is Pb-Pa> 0 and is opened so as not to become excessively large. This is performed by automatically controlling the opening degree of the valve 17 by the degree adjuster 18.

The massive synthetic resin material stored in the storage hopper 14 is cut out by the cutting device 30 into the replenishing hopper 15, and further cut out from the replenishing hopper 15 by the cutting device 31 into the supply hopper 13. This replenishing hopper 15
In order to prevent the pressurized gas in the supply hopper 13 from backflowing toward the replenishment hopper 15 side when the massive synthetic resin material is cut out from the replenishment hopper 15 to the supply hopper 13, the replenishment hopper 15 After closing the decompression valve 23, the valve 22 of the communication pipe 21 is opened to equalize the pressure of the supply hopper 13 and the replenishment hopper 15, and thereafter, the block synthetic resin material is cut out from the replenishment hopper 15 to the supply hopper 13. I do. After the block synthetic resin material is cut out, the valve 22 is closed and the pressure reducing valve 23 is opened to reduce the pressure in the refilling hopper 15 to atmospheric pressure.
The block-shaped synthetic resin material can be cut out from the storage hopper 14 to the refilling hopper 15.

[Operation Example 1] As an example of the present invention, FIG.
8 to the tuyere B of the furnace body shown in FIG.
A test furnace for scrap melting (within a furnace)
Volume: 2.5m^Three, Pig iron production: 10t / day) and Fig. 1
8 to the tuyere B of the furnace body of the present invention shown in FIGS.
Test furnace for scrap melting with combustion burner (furnace contents
Product: 2.5m ^Three, Pig iron production: 10t / day)
Used, scrap characterized by the above-mentioned configurations
The dissolution method was performed.

In this operation example, the pre-combustion chamber 1 of each combustion burner is used.
Pulverized coal and oxygen at room temperature are blown into each of the outlets, and [P
C / O ₂ ] was changed to melt the scrap to produce hot metal. Also, in order to adjust the combustion temperature at the tuyere to 2000 ° C., steam was blown into the pre-combustion chamber as a coolant. The shaft furnace 31 shown in FIG. 18 has a structure in which a raw material charging device 133 is continuously provided above the furnace top 32, and the raw material charging device 33 and the inside of the furnace can be shut off by an opening / closing device 34. The furnace top gas can be completely recovered through the duct 35.

As a comparative example, a test furnace having a furnace body shown in FIG. 18 with tuyere portions shown in FIG. 21 and a combustion burner having a structure shown in FIG. 20 at tuyere B of the furnace body shown in FIG. Pulverized coal and a plastic material having an average particle size of 5 mm or less were blown in using a test furnace equipped with, and the scrap was melted by changing [PC / O ₂ ] to produce hot metal. In addition,
FIG. 21 shows a method of blowing pulverized coal through a lance into hot air enriched with oxygen based on a known cupola method, at a temperature of 80
[PC / O ₂ ] was changed by adjusting the amount of oxygen enrichment and the amount of pulverized coal using hot air at 0 ° C. In this operation example, pulverized coal having a particle size of 74 μm or less and 75% and having an industrial analysis value shown in Table 1 was used for blowing, and blast furnace coke was used as coke. In addition, since this operation example is performed to check the combustibility of pulverized coal, the charging port 3
No plastic material was blown in from.

In order to check the blowing limit of the pulverized coal in the examples of the present invention and the comparative examples, the dust in the furnace top gas was sequentially sampled and the C concentration (%) in the dust was measured. The result is shown in FIG. Fig. 19 shows the input pulverized coal ratio PC (kg / t · pi
g) and oxygen supply amount O ₂ (Nm ³ / t · pig) [PC / O
₂ ] and the C concentration in the furnace top dry gas,
In the comparative example by the method of FIG. 21, when the value of [PC / O ₂ ] is 0.7 kg / Nm ³ or more, the C concentration in the furnace top dust increases rapidly. This indicates that when [PC / O ₂ ] is in this region, the pulverized coal is not completely burned at the tuyere and is discharged unburned from the top of the furnace. It means that it is not fully used as fuel. Further, in the comparative example using the combustion burner of FIG. 20, although the C concentration in the furnace top dry dust is at a lower level than that in the comparative example, [PC / O ₂ ]: 1.3 kg /
Below Nm ³ , the C concentration exceeds 25%.

On the other hand, in the example of the present invention using the combustion burner shown in FIGS. 14 and 15, [PC / O ₂ ] was 1.4.
The C concentration in the furnace top dry gas is low up to around kg / Nm ³ ,
Particularly, [PC / O ₂ ]: 1.3 kg / Nm ³ or less, the C concentration is less than 25%, and it can be seen that even if a large amount of pulverized coal is blown, it is highly efficiently combusted and combusted and gasified.
Further, in the example of the present invention using the combustion burner of FIGS. 16 and 17, the pulverized coal burns with higher efficiency, so that the C concentration is lower. As described above, [PC / O ₂ ] has a stoichiometrically upper limit of 1.4 kg / Nm ³ , and in the examples of the present invention, [PC / O ₂ ]: 1.4.
The sharp increase in the C concentration in the furnace top dry gas in the vicinity of kg / Nm ³ does not indicate the limit of the combustion burner of the present invention.
As is clear from this operation example, according to the combustion burner of the present invention, pulverized coal and oxygen are rapidly mixed in the pre-combustion chamber and pulverized coal is rapidly combusted, so that [PC / O ₂ ] is sufficiently increased. Can efficiently combust pulverized coal for combustion gasification.

[0065]

[Table 1]

[Operation Example 2] The same scrap melting method as in Operation Example 1 was carried out. This operation example is the same as operation example 1 in FIG.
A test furnace equipped with the combustion burner of the present invention shown in FIGS. 14 and 15 at the tuyere B of the furnace body shown in FIG. 8 and a combustion burner having the structure shown in FIG. 20 at the tuyere B of the furnace body shown in FIG. The scrap was melted by using the test furnace provided and the test furnace having the tuyere portion shown in FIG. 21 in the furnace body shown in FIG. 18, respectively, to produce hot metal. The same pulverized coal and coke as in Operation Example 1 are used, and the synthetic resin material has an average particle size of 10 to 25 m.
m plastic material was used. Also, in this operational example,
In some of the comparative examples, secondary combustion air was introduced into the furnace shaft portion to secondarily combust the combustion gas. Tables 2 to 6 show the operating conditions and the results of each example.

In Tables 2 to 6, Nos. 1 to No. Four
Is an operation example in which pulverized coal is blown in using the combustion burner of the present invention, No. 5-No. No. 8 is an operation example in which a lumpy plastic material is blown together with pulverized coal by using the combustion burner of the present invention, No. 9-No. 12 is an operation example in which blowing is performed by the conventional lance method shown in FIG. 21,
No. 13-No. 19 is an operation example using the combustion burner of the comparative example shown in FIG.

No. 1 to No. No. 4 blows pulverized coal together with oxygen using the combustion burner of the present invention. 1 → N
o. In this example, the pulverized coal ratio was increased in the order of 4. Of these, No. 1 is blowing pulverized coal, but [P
Since C / O ₂ ] is low, FeO in the slag is high. Also, in this operation example, the pulverized coal ratio / coke ratio is 0.
The coke ratio is relatively high, which is a problem in terms of manufacturing cost. On the other hand, No. which is a preferable operation example. 2-No. In 4, FeO in the slag is low,
The quality of hot metal and iron yield are good. In addition, in these operation examples, the furnace conditions were favorable, and the injection of pulverized coal was substantially stoichiometrically limited to [PC / O ₂ ] [P
C / O ₂ ]: It was possible to blow up to 1.4 kg / Nm ³ . In addition, the coke ratio gradually decreased as the amount of pulverized coal blown increased, and it was possible to carry out cost-effective operation. Further, since the pulverized coal is efficiently burned by the combustion burner, a large amount of high calorie exhaust gas of 2800 kcal / Nm ³ or more is obtained.

No. 5-No. No. 8 is an operation example in which the lump plastic material was blown together with the pulverized coal in order to investigate the flammability of the lump plastic material by the combustion burner of the present invention. In these operation examples, the furnace conditions were also favorable. In addition, especially No. In 8 about the injection of plastic material (Plastic ratio: PLA) [PL
[A / O ₂ ] is a stoichiometric limit [PLA /
O ₂ ]: The plastic material could be blown up to near 1.0 kg / Nm ³ . In addition, the coke ratio gradually decreased as the injection amount of the plastic material increased, and the cost-effective operation could be performed. This is because a plastic material with inferior flammability due to its large particle size and small specific surface area
This shows that the combustion was efficiently performed in the pre-combustion chamber and the tuyere inside the burner.

No. 9-No. 12 is an operation example in which pulverized coal or pulverized coal + plastic material is blown from the tuyere by the conventional lance method. Of these, No. 9 is an operation example in which pulverized coal is blown together with oxygen, No. 9 10 is an operation example in which pulverized coal was blown in together with oxygen-enriched air. In these operation examples, the combustion efficiency of pulverized coal is low [P
C / O ₂ ] cannot be raised, and thus a large amount of coke is required as compared with pulverized coal, and the manufacturing cost is high. Further, since the contact between the pulverized coal and oxygen at the tuyere tip is not sufficiently secured, the FeO content in the slag is high and the iron yield is reduced.

No. No. 11 is an operation example in which pulverized coal was blown in together with oxygen-enriched air, and air for secondary combustion was introduced into the furnace shaft portion.
Although the fuel ratio can be made lower than that of No. 10, No. For the same reason as in No. 10, the combustion efficiency of pulverized coal is low and the coke ratio is high, so the manufacturing cost is high. Further, since the oxygen-enriched air is used and the combustion gas generated by the combustion of pulverized coal is secondarily combusted, the calorie of the exhaust gas is extremely low (less than 1800 kcal / Nm ³ ). In addition, No. 10
Similar to the above, since the contact between oxygen and pulverized coal is not sufficiently secured, FeO in the slag is high, and a decrease in iron yield cannot be avoided.

No. 12 is an operation example in which pulverized coal and a plastic material are blown together with oxygen. This operation example is [P
LA / O ₂ ]: 0.2 kg / Nm ³ , [PC / O ₂ ]:
It is 0.6 kg / Nm ³ , and the coke substitution rate R by the plastic material is extremely low at 3.2%, despite the fact that the amount of pulverized coal and the plastic material injected is relatively small and oxygen is in excess. This indicates that a plastic material having a large particle size and a small specific surface area and having inferior combustibility cannot be efficiently combusted at the tuyere, and therefore is not effectively used as a fuel.

No. No. 13 is an operation example in which oxygen-enriched air is blown from around the pulverized coal using the combustion burner shown in FIG. Due to the same reason as in 10, it is not possible to sufficiently secure the contact between oxygen and pulverized coal, and therefore the combustion efficiency of pulverized coal is low, and therefore the coke ratio must be increased, resulting in high manufacturing cost. Moreover, since oxygen-enriched air is used, the calorie of the exhaust gas is low (less than 2500 kcal / Nm ³ ). Furthermore, No. 10
Similar to the above, since the contact between oxygen and pulverized coal is not sufficiently secured, FeO in the slag is high, and a decrease in iron yield cannot be avoided.

No. No. 14 is an operation example in which oxygen-enriched air is blown from around the pulverized coal using the combustion burner shown in FIG. 20, and air for secondary combustion is introduced into the furnace shaft portion. Although the fuel ratio can be made lower than that of No. 13, No. 13 For the same reason as in No. 13, it was not possible to ensure sufficient contact between oxygen and pulverized coal, so the combustion efficiency of pulverized coal was low, and the coke ratio was higher than in the operation example using the combustion burner of the present invention. Manufacturing cost is high because it cannot help but be forced. Further, since the oxygen-enriched air is used and the exhaust gas is secondarily burned, the calorie of the exhaust gas is extremely low (less than 1800 kcal / Nm ³ ). Furthermore, No. As with No. 13, since the contact between oxygen and pulverized coal is not sufficiently ensured, FeO in the slag is high, and a decrease in iron yield cannot be avoided.

No. No. 15 is an operation example in which pulverized coal and a plastic material are blown using the combustion burner shown in FIG. 20, and oxygen-enriched air is blown from the surroundings. Although it is improved compared with 12, the absolute value is less than 10%, and the blown plastic material is not effectively used as a fuel.
No. 16-No. No. 18 is an operation example in which oxygen was blown from around the pulverized coal using the combustion burner shown in FIG. No. 16 is No. 2 and No. No. 17 is No. 3
No. No. 18 is No. No. 4 and [PC / O ₂ ] are the same. These Nos. 16-N
o. No. 18 is No. 2-No. As compared with No. 4, the combustion efficiency of pulverized coal is low, so the coke ratio is high, and since a combustion zone is formed at the tuyere, FeO in the slag is No. 2-No. Four
It is higher than that of the steel, and the yield of iron decreases. No.
No. 19 is an operation example in which pulverized coal and a plastic material are blown using the combustion burner shown in FIG. 20 and oxygen is blown from the surroundings. 12 or N
o. Although it is better than 15, it is still at a low level.

As is apparent from the above operation example, the use of the combustion burner of the present invention enables efficient combustion of the lumpy synthetic resin material, and a large amount of pulverized coal in the furnace and operating conditions. It is possible to stably and highly efficiently combust gasification regardless of conditions, etc., and further, under the operation with a high fuel ratio and a high pulverized coal ratio, by efficiently melting scrap and obtaining a large amount of high-calorie exhaust gas, In order to realize cost operation, oxygen is blown together with the pulverized coal from the combustion burner at the tuyere, and pulverized coal and oxygen are blown by using the combustion burner of the present invention to realize rapid combustion of the pulverized coal. , To realize stable and highly efficient combustion of pulverized coal without being affected by the situation inside the furnace, to prevent the combustion gas of the combustion of pulverized coal from being significantly secondary burned,
It turns out that it is necessary to satisfy all the conditions.

[0077]

[Table 2]

[0078]

[Table 3]

[0079]

[Table 4]

[0080]

[Table 5]

[0081]

[Table 6]

[0082]

As described above, according to the combustion burner of the present invention, it is possible to efficiently burn massive solid fuel such as massive synthetic resin material. Therefore, a large amount of synthetic resin material is used in the metallurgical furnace. It can be processed at low cost without crushing and can be effectively used as fuel. Further, according to the combustion burner of the present invention shown in FIGS. 2 and 3,
It is possible to stably and efficiently burn a fuel such as pulverized coal supplied from the tuyere of an iron-making melting furnace, etc., without being affected by the conditions inside the furnace. For this reason, inexpensive pulverized coal can be used in large quantities for melting the iron source in the melting furnace for iron making, etc., and moreover, massive synthetic resin material that is waste can be used in large quantities, so that the manufacturing cost of hot metal can be It can be significantly reduced compared to. Further, when used in a melting furnace in the novel scrap melting method as described above, since it is possible to stably and efficiently combust a pulverized coal that is supplied in a large amount in the furnace to combustion gasification, scrap and fine powder The production of hot metal and gas for high-calorie fuel using charcoal as the main raw material can be carried out at low cost.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing an embodiment of a combustion burner of the present invention.

FIG. 2 is a vertical sectional view showing another embodiment of the combustion burner of the present invention.

FIG. 3 is a vertical sectional view showing another embodiment of the combustion burner of the present invention.

FIG. 4 is an explanatory view showing an arrangement example of oxygen blowout holes and solid fuel blowout holes in a burner radial direction in the structure of the combustion burner shown in FIG.

5 is an explanatory view showing another example of the arrangement of the oxygen blowout holes and the solid fuel blowout holes in the burner radial direction in the structure of the combustion burner shown in FIG.

6 is an explanatory view showing an example of arrangement of oxygen blowout holes and solid fuel blowout holes in a burner radial direction in the structure of the combustion burner shown in FIG. 3. FIG.

7 is an explanatory view showing another example of the arrangement of the oxygen blowout holes and the solid fuel blowout holes in the burner radial direction in the structure of the combustion burner shown in FIG.

8 is an explanatory view showing another example of the arrangement of the oxygen blowout holes and the solid fuel blowout holes in the burner radial direction in the structure of the combustion burner shown in FIG.

FIG. 9 is a graph showing the relationship between the average particle size of the synthetic resin material supplied and the combustibility (coke substitution rate) for the combustion burner of the present invention and the combustion burner of the comparative example.

FIG. 10 is a graph showing the burning rate of pulverized coal over time in the case of using the combustion burner of the present invention and the case of using the combustion burner of the comparative example.

FIG. 11 is an explanatory diagram showing ideal combustion conditions of pulverized coal near the tuyere when the combustion burner of the present invention is used and when the combustion burner of the comparative example is used.

FIG. 12 is a vertical sectional view showing an embodiment of a combustion burner of the present invention.

13 is a sectional view taken along the line XIII-XIII in FIG.

FIG. 14 is a longitudinal sectional view showing another embodiment of the combustion burner of the present invention.

15 is a sectional view taken along the line XV-XV of FIG.

FIG. 16 is a longitudinal sectional view showing another embodiment of the combustion burner of the present invention.

17 is a sectional view taken along the line XVII-XVII in FIG.

FIG. 18 is a conceptual diagram showing a configuration example of a scrap melting furnace to which the combustion burner of the present invention is applied.

FIG. 19 is a graph showing the relationship between [PC / O ₂ ] and the C concentration in the furnace top dry gas when the combustion burner of the present invention is used and when the combustion burner of the comparative example is used.

FIG. 20 is an explanatory view showing a sectional structure of a tuyere provided with a combustion burner having no pre-combustion chamber.

FIG. 21 is an explanatory view showing a cross-sectional structure of a conventional tuyere.

[Explanation of symbols]

1 ... Pre-combustion chamber, 2 ... Burner tip opening, 3 ... Charging inlet, 4
… Furnace wall, 5… Burner body, 6… Water cooling jacket, 7,
7 '... Oxygen supply pipe, 8 ... Viewing window pipe body, 9 ... Pilot burner, 10 ... Refractory material, 11 ... Charging chute, 12 ... Fixed amount cutting device, 13 ... Supply hopper, 14 ... Storage hopper, 15
... replenishing hopper, 16 ... gas supply pipe, 17 ... valve, 1
8 ... Opening degree regulator, 19a, 19b ... Pressure gauge, 20 ... Differential pressure detector, 21 ... Communication piping, 22 ... Valve, 23 ... Pressure reducing valve, 24 ... Water cooling jacket, 25 ... Tuyere, 26a, 2
6b, 27a, 28a ... Piping, 29 ... Solid fuel supply pipe,
30, 31 ... Cutout device, 31 ... Shaft furnace, 32 ... Furnace top part, 33 ... Raw material charging device, 34 ... Opening / closing device, 35 ... Duct, a, a '... Oxygen blowing hole, b ... Solid fuel blowing hole, c ...
Peep window, A ... combustion burner, B ... tuyere

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Tatsuro Ariyama 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Inside Nihon Kohkan Co., Ltd. (72) Hidetoshi Noda 1-2-1 Marunouchi, Chiyoda-ku, Tokyo Nippon Steel Tube Co., Ltd. (72) Inventor Masahiro Matsuura 1-2-2 Marunouchi, Chiyoda-ku, Tokyo Nihon Steel Tube Co., Ltd. (72) Inventor Takanori Inoguchi 1-2-1 Marunouchi, Chiyoda-ku, Tokyo Nihon Inside Steel Pipe Co., Ltd. (72) Inoue, Noboru Nozoe, Tokyo, Koto-ku, Tokyo 2-11-1, Kawasaki Heavy Industries, Ltd. (72) Inventor Kenji Kimura 2--11, Minamisuna, Koto-ku, Tokyo Kawasaki Heavy Industries Ltd. Tokyo Design Office (72) Inventor Eiichi Harada 1-1 Kawasaki-cho, Akashi-shi, Hyogo Kawasaki Heavy Industries Ltd. Akashi Plant

Claims (5)

[Claims] 1. A combustion burner provided at the tuyere of a lower part of a shaft furnace, wherein the combustion burner has a pre-combustion chamber inside the tip end opening thereof, and the solid solid fuel is contained in the pre-combustion chamber. A combustion burner used in a metallurgical furnace, which has a charging inlet for charging and an oxygen blowing hole inside the pre-combustion chamber. 2. A combustion burner provided at the tuyere of a lower part of a shaft furnace, wherein the combustion burner has a pre-combustion chamber inside an opening of the tip thereof, and the solid solid fuel is contained in the pre-combustion chamber. It has a charging port for charging, and has a solid fuel blowout hole arranged inside or in the vicinity of the center of the burner radial direction inside the pre-combustion chamber, and an oxygen blowout hole arranged around it. A combustion burner used in a metallurgical furnace. 3. A combustion burner provided at the tuyere of the lower part of a shaft furnace, wherein the combustion burner has a pre-combustion chamber inside the tip opening, and the solid fuel is in the pre-combustion chamber. An oxygen outlet is provided inside the pre-combustion chamber at or near the radial center of the burner, a solid fuel outlet is provided around the oxygen inlet, and the surroundings thereof. A combustion burner used in a metallurgical furnace, the burner having an oxygen blowout hole disposed in. 4. The combustion burner used in the metallurgical furnace according to claim 1, wherein the axis of the burner has an inclination angle θ such that the tip end side of the burner is downward with respect to the horizontal direction. 5. The solid fuel blowout hole and the oxygen blowout hole are configured such that the intersection of the hole axis extension lines of the solid fuel blowout hole and the oxygen blowout hole is located near the tip exit of the precombustion chamber or inside the burner than that. A combustion burner used in the metallurgical furnace according to 2, 3, or 4.