JP3293430B2 - Scrap melting method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a scrap melting method,
More specifically, scrap metal is produced using scrap as an iron source, pulverized coal and synthetic resin as waste as main heat sources, and also producing high calorie exhaust gas having high utility value as a fuel gas. About the law.

[0002]

2. Description of the Related Art In recent years, the supply of scrap (pig waste, iron waste) has been steadily increasing, and recycling thereof has become an important issue in terms of effective use of resources. For this reason, there is a strong demand for the development of technology that can produce hot metal at a low cost and with high productivity using scrap as a raw material. Conventionally, an electric furnace has been used to produce hot metal from scrap,
The electric furnace method requires a huge amount of electricity and is expensive,
The requirements in terms of manufacturing cost cannot be satisfied.

[0003] In addition, casting iron is produced from scrap by the cupola method. In the cupola method, it is necessary to use high-grade large coke for casting as a fuel. 4 of coke for blast furnace
Since it is about twice as expensive, it is difficult to generalize it in terms of manufacturing costs. In the cupola method, the oxygen in the hot air blown from the tuyere is not rapidly consumed by the coke at the tuyere to promote the smooth dissolution of the scrap. It is necessary to make the temperature distribution such that the maximum temperature is reached in this part. For this reason, it is necessary to use coke having lower reactivity and less combustibility than coke for blast furnace. For this reason, it is essential to use a special casting coke having a larger particle size and a lower reactivity than the blast furnace coke.

In contrast to the above-mentioned conventional electric furnace method and cupola method, as a scrap melting method using a shaft furnace, scrap as an iron source and blast furnace coke are charged into the shaft furnace, High temperature oxygen-enriched air and pulverized coal at normal temperature are blown from the mouth to burn, and the scrap is melted by the sensible heat of this combustion gas. A scrap melting method that promotes melting has been proposed (Iron and Steel Vol.79, No.2, pp.139-14)
6).

[0005] As another method, a combustion furnace for pulverized coal combustion is provided outside a shaft furnace, a large amount of pulverized coal is burned in the combustion furnace, and the generated high-temperature combustion gas is charged into scrap and coke. A scrap melting method has been proposed in which the gas is introduced into a shaft furnace, and at the time of the introduction, an oxygen-containing gas is supplied to the combustion furnace to cause secondary combustion of the combustion gas, and the scrap is melted by the sensible heat of the combustion gas. (JP-A-1-195225). The scrap melting method according to these proposals uses pulverized coal as a part of the heat source and can use inexpensive blast furnace coke as the coke charged into the furnace, so that there is a possibility that economical operation can be realized.

[0006]

However, each of the two scrap melting methods described above is a technique aimed at energy minimum with a low fuel ratio, and therefore, the operation with a low fuel ratio (fuel ratio: 300 kg / t) (<Pig), and by blowing oxygen-containing gas such as air into the combustion gas generated by the combustion of pulverized coal to perform secondary combustion, thereby promoting scrap melting at a low fuel ratio. . That is, the aim of these conventional scrap melting methods is to reduce the fuel ratio and reduce the cost of scrap melting by using pulverized coal as a part of the heat source. There is no intention to produce a large amount of exhaust gas (fuel gas) by mass-supplying and operating at a high fuel ratio, and actively combusting and gasifying the large amount of pulverized coal to produce a large amount of exhaust gas (fuel gas). There are no special operating conditions or means.

In the above-mentioned scrap melting method, pulverized coal is used as a part of the heat source in order to reduce the production cost, but the amount of the supplied pulverized coal is 1 weight ratio of [pulverized coal ratio / coke ratio]. Less than 0 (at most about 0.9)
Although the fuel ratio is kept low, it is difficult to say that the cost has been sufficiently reduced in the sense that the coke ratio is relatively high. In addition, in these scrap melting methods, in order to enable operation at a low fuel ratio, 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 the secondary combustion, the discharged exhaust gas necessarily contains a large amount of nitrogen, CO _{2, and the} like. Therefore, the exhaust gas discharged from the furnace in the conventional scrap melting method has a certain use value as a fuel gas, but can be used as a fuel gas for performing high-efficiency power generation or a fuel gas for a heating furnace, for example. It is not a high calorie gas with a high calorific value.

For example, in the former literature (iron and steel Vol. 79, No. 2, pp. 139 to 146), high calorie exhaust gas is obtained as compared with the cupola method, and this is used as fuel gas. But the calorie of the exhaust gas is about 2000 kcal / Nm ³ (about 8400 kJ / Nm ³ )
Only about. In addition, the document also shows data of an experimental example performed without performing secondary combustion on a trial basis,
According to the results calculated by the present inventors, even in this case, the calories of the exhaust gas are at most only 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 a high-efficiency power generation. Therefore, the exhaust gas obtained by the conventional technique is suitable for a heating furnace or a high-efficiency power generation. It has to be said that it is of low utility value. In addition, since the operation is performed at a low fuel ratio, the amount of exhaust gas generated is small, and the exhaust gas calorie is low, which is not a technology capable of stably supplying a large amount of high-quality fuel gas.

Further, the latter prior art (Japanese Patent Laid-Open No. 1-195)
No. 225) requires a combustion furnace for pulverized coal combustion in addition to a melting furnace, so equipment costs are high. In addition, gas sensible heat is generated while a high-temperature gas generated in the combustion furnace is guided to a shaft furnace by a gas conduit. There is also a problem in terms of economics because part of the data is lost. As an improved technique of the cupola method described above, a method in which hot air enriched with oxygen is blown together with pulverized coal from tuyeres is also proposed (Klaus Scheiding: Proceedin
gs of the Eighth Japan-Germany Seminar, Oct., 6,7,1
993 (Sendai, Japan), p.22 “Hot Metal Production
Based on Scrap, Coal and Oxygen ")
In this method, large diameter coke must be used among coke for blast furnace, and there is a problem that the production cost is increased. Also, as in the prior art described above, this technology has no intention to supply a large amount of pulverized coal to convert it into combustion gas, and it is provided with operating conditions and means that enable this. However, even if hot air containing nitrogen is blown, it is hardly expected to obtain high calorie exhaust gas.

As described above, the conventionally proposed scrap melting technology basically aims at the energy minimum by reducing the fuel ratio, so that the exhaust gas has a small calorific value and a small discharge amount, and is of low utility value. It was low. In addition, although pulverized coal is used as a part of the heat source, the pulverized coal ratio cannot be sufficiently increased with respect to the coke ratio because highly efficient combustion of pulverized coal cannot be realized.
Cost reduction by using pulverized coal has not been sufficiently achieved.
On the other hand, in recent years, synthetic resins such as plastics have been rapidly increasing 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.

[0011] Accordingly, an object of the present invention is to provide a method for producing hot metal by dissolving scrap with high efficiency and producing a large amount of high calorie exhaust gas having high utility value as a fuel gas, in comparison with the conventional scrap melting technique described above. It can be operated at a considerably lower production cost compared to the prior art when considering the utilization value of high-calorie exhaust gas, and is synthesized as part of a heat source and high-calorie exhaust gas source. It is an object of the present invention to provide a completely new type of scrap dissolving method which enables mass processing and effective utilization of synthetic resins as wastes by utilizing resins.

[0012]

The present invention SUMMARY OF THE INVENTION a high fuel ratio due to the production of manufacturing and high-calorie exhaust gas hot metal to scrap mentioned above as a raw material the purpose of implementing a low-cost, mass-blowing of the pulverized coal, high This is achieved by the following means under operation at a pulverized coal ratio .
Oxygen is blown in along with pulverized coal from the tuyere combustion burner. The pulverized coal and oxygen are blown in by a specific method such that they are brought into contact with each other and mixed quickly, thereby realizing rapid combustion of the pulverized coal. Particularly preferably, most of the combustion of the pulverized coal is performed inside the combustion burner at the tuyere, thereby realizing stable and efficient combustion of the pulverized coal without being affected by the conditions inside the furnace. The combustion gas from pulverized coal combustion is not significantly secondary burned. Combustion burner
Pulverized coal ratio PC (kg / t-pig) (and
Plastic material ratio (kg / t · pig)) and oxygen flow rate O ₂ (Nm
³ / t · pig) [PC / O ₂ ] of 0.7 kg / N
m ³ or more. Fuel ratio less than 300kg / t-pig
Above, pulverized coal ratio (kg / t-pig) (and synthetic resin material ratio
(Kg / t · pig)) and coke ratio (kg / t · pig)
The weight ratio [pulverized coal ratio / coke ratio] is set to 1.0 or more.

[0013] At the same time, the present inventors have studied the melting of scrap.
Synthetic resin as part of heat source and high calorie exhaust gas source
Of furnaces inside the furnace, and as a result,
the above~ Scrap melting method characterized by the following structure
The synthetic resin material together with pulverized coal through a combustion burner.
The synthetic resin material is burned into the combustion
Waste or pyrolyzed,
Mass processing of synthetic resin materials, heat source and high calorie exhaust gas source
On the other hand,
Synthetic resin as originally expected in the clap dissolution method
The problem of materials entering the furnace interior, that is,
Is said to account for about 20% of the synthetic resin material
Emission of HCl generated by combustion of nitro materials and synthetic resin
Exhaust gas due to tar-like substances generated by decomposition products of wood
While properly avoiding problems such as clogging of piping,
Mass loading and processing is possible, and synthetic resin is practical
Mass use of wood as heat source and high calorie exhaust gas source
It turns out that it can be done.

The present invention has been made on the basis of such knowledge, and the characteristic configuration thereof is as follows. (1) was charged with scrap and coke is iron source into the shaft furnace, pulverized coal ratio is from combustion burner provided in the tuyere
PC (kg / t · pig) and synthetic resin material ratio SR (kg / t
(t · pig) and oxygen flow rate O ₂ (Nm ³ / t · pig)
[(PC + SR) / O ₂ ] is 0.7 kg / Nm ³ or more.
Under such conditions, pulverized coal, powdery or granular synthetic resin material and oxygen are blown into the furnace, and the fuel ratio is set to 300 kg /
At least t · pig, the ratio of pulverized coal supplied to the combustion burner (k
g / t-pig) and synthetic resin material ratio (kg / t-pig) and furnace
Weight ratio with coke ratio (kg / t-pig) charged to the top
[(Pulverized coal ratio + synthetic resin material ratio) / coke ratio] to 1.0
The scrap melting method implemented under the above operating conditions
Thus, the pulverized coal, powdery or flaky synthetic resin material and
In the blowing of oxygen and pulverized coal , the pulverized coal and the synthetic resin material are blown from or near the center in the burner radial direction, and oxygen is blown from the periphery thereof to mix the pulverized coal and the synthetic resin material with oxygen, thereby reducing the pulverized coal and the synthetic resin material. both were rapidly burned in the combustion zone that forms part of a synthetic resin material tuyere, with the production of molten iron by dissolving the scrap sensible heat of the combustion gases, significantly secondary the combustion gas in a furnace A scrap melting method characterized by recovering the fuel gas without burning it.

(2) Scrap and coke, which are iron sources, are charged into a shaft furnace, and a pulverized coal ratio PC (kg / t · pig) and a synthetic resin material ratio are obtained from a combustion burner provided at the tuyere.
SR (kg / t · pig) and oxygen flow rate O ₂ (Nm ³ / t · p)
ig) and the ratio [(PC + SR) / O ₂ ] is 0.7 kg / N.
pulverized coal under conditions such that m ³ or more, blowing a powdery or strip-shaped synthetic resin material and oxygen in the furnace, the fuel ratio 3
More than 00 kg / t · pig
Pulverized coal ratio (kg / t-pig) and synthetic resin material ratio (kg / t
・ Pig) and the coke ratio charged into the furnace top (kg / t ・ pig)
Weight ratio [(pulverized coal ratio + synthetic resin ratio) / coke ratio]
Melting performed under operating conditions with
Solution, wherein said pulverized coal, pulverized or flake-like synthesis
In blowing the resin material and oxygen, oxygen is blown from the center or in the vicinity of the burner radial direction, pulverized coal and synthetic resin material are blown from around the burner, and oxygen is blown from the surroundings to form pulverized coal and synthetic resin material and oxygen. By causing pulverized coal and at least a part of the synthetic resin material to burn rapidly in a combustion zone formed at the tuyere tip,
Scrap melting method characterized by the addition to produce the molten iron by dissolving the scrap sensible heat of the combustion gas is recovered as a fuel gas without significant secondary combustion of the combustion gas in the furnace.

(3) A shaft furnace equipped with a tuyere with a combustion burner provided with a pre-combustion chamber inside the burner tip opening is used.
Then, scrap and coke, which are iron sources, are charged into the shaft furnace, and the pulverized coal ratio P is set in the pre-combustion chamber of the combustion burner.
C (kg / t · pig) and synthetic resin material ratio SR (kg / t
Pig) and the oxygen flow rate O ₂ (Nm ³ / t · pig)
[(PC + SR) / O ₂ ] is 0.7 kg / Nm ³ or more.
While pulverized coal and oxygen are blown under such conditions, pulverized or flaky or massive synthetic resin material is blown or charged, and the fuel ratio is 300 kg / t · pig or more,
Pulverized coal ratio (kg / t · pig) to be supplied to the combustion burner
And the ratio of synthetic resin material (kg / t-pig)
Weight ratio to the groundwater ratio (kg / t · pig) [(pulverized coal ratio +
(Synthetic resin material ratio) / coke ratio] 1.0 or more
A scrap melting method carried out under conditions, wherein the fine powder
When blowing the coal, the granular or flake-shaped synthetic resin material and the oxygen , at least pulverized coal is blown from the burner radial center or the vicinity thereof, and oxygen is blown from the surroundings to mix the two. By doing so, the pulverized coal and at least a part of the synthetic resin material are rapidly burned in the pre-combustion chamber, the combustion gas is introduced into the furnace through the burner tip opening, and the scrap is melted by the sensible heat of the combustion gas. A scrap melting method, wherein hot metal is produced and the combustion gas is recovered as a fuel gas without significant secondary combustion in a furnace.

(4) A shaft furnace equipped with a tuyere with a combustion burner provided with a pre-combustion chamber inside the burner tip opening is used.
Then, scrap and coke, which are iron sources, are charged into the shaft furnace, and the pulverized coal ratio P is set in the pre-combustion chamber of the combustion burner.
C (kg / t · pig) and synthetic resin material ratio SR (kg / t
Pig) and the oxygen flow rate O ₂ (Nm ³ / t · pig)
[(PC + SR) / O ₂ ] is 0.7 kg / Nm ³ or more.
While pulverized coal and oxygen are blown under such conditions, pulverized or flaky or massive synthetic resin material is blown or charged, and the fuel ratio is 300 kg / t · pig or more,
Pulverized coal ratio (kg / t · pig) to be supplied to the combustion burner
And the ratio of synthetic resin material (kg / t-pig)
Weight ratio to the groundwater ratio (kg / t · pig) [(pulverized coal ratio +
(Synthetic resin material ratio) / coke ratio] 1.0 or more
A scrap melting method carried out under conditions, wherein the fine powder
When blowing coal, powdery or flake-shaped synthetic resin material and oxygen, oxygen is blown in from the burner radial center or in the vicinity thereof, and at least pulverized coal is blown from around the burner, and further around the burner. Pulverized coal and at least part of the synthetic resin material are rapidly burned in the pre-combustion chamber by blowing oxygen from the pulverized coal and oxygen, and the combustion gas is introduced into the furnace from the burner tip opening, with the production of molten iron by dissolving the scrap sensible heat of the combustion gas, scrap melting method characterized by recovering the combustion gas as a fuel gas without significant secondary combustion in the furnace.

In the scrap melting methods (1) to (4), the blowing of the synthetic resin material by the combustion burner or the blowing or charging of the synthetic resin material into the pre-combustion chamber is performed discontinuously or intermittently. The synthetic resin material may be blown or charged at the same time as the pulverized coal is blown, or may be temporarily replaced with the pulverized coal blow (that is, the blown pulverized coal is blown). (Temporary stop). That is, in the method of the present invention, blowing or charging a synthetic resin material through a combustion burner means that:
Such cases are included. Also especially above
In the scrap melting method of (3), it is possible to blow a synthetic resin material in the form of powder or granules into the pre-combustion chamber from or near the center of the burner radial direction, and in the scrap melting method of (4), It is preferable to blow the synthetic resin material in the form of powder or particles into the pre-combustion chamber from around the oxygen blown from the burner radial center or its vicinity into the pre-combustion chamber in order to burn the synthetic resin material with high efficiency.

In the present invention, blast furnace coke can be used as the coke charged into the shaft furnace .

In the scrap melting method of the above (1), when oxygen is blown from around a pulverized coal and a synthetic resin material blowing section (hereinafter, referred to as a solid fuel blowing section), a ring is formed around the solid fuel blowing section. Oxygen may be blown from an oxygen blowing section surrounding the solid fuel blowing section, or oxygen may be blown from a plurality of oxygen blowing sections arranged at appropriate intervals around the solid fuel blowing section. Further, the position of the solid fuel injection section in the burner radial direction may be deviated to some extent from the center of the burner. In short, pulverized coal and synthetic resin material are blown from or near the center in the burner radial direction. Oxygen is blown from the air.

In the scrap melting method of the above (2), when pulverized coal and synthetic resin material are blown from around the oxygen blown from the center in the burner radial direction or in the vicinity thereof, the periphery of the oxygen blowing portion is formed in a ring shape. Pulverized coal and synthetic resin material may be blown from a solid fuel injection section surrounded by the solid fuel injection section, or pulverized coal and synthetic resin may be injected from a plurality of solid fuel injection sections arranged at appropriate intervals around the oxygen injection section. A resin material may be blown. Further, even when oxygen is further blown from the periphery of the solid fuel injection unit, oxygen may be blown from an oxygen injection unit that annularly surrounds the solid fuel injection unit, or the solid fuel injection unit may Oxygen may be blown out from a plurality of oxygen blowing sections arranged at appropriate intervals around the circumference. Further, the position of the oxygen injection section in the burner radial direction (the position of the oxygen injection section inside the solid fuel injection section) may be deviated to some extent from the center of the burner. Oxygen is blown from above, and pulverized coal and a synthetic resin material may be blown from around.

In the scrap melting method of the above (3), when oxygen is blown from around the solid fuel blowing section in the pre-combustion chamber of the combustion burner, the oxygen blowing section surrounding the solid fuel blowing section in a ring shape is used. Oxygen may be blown from the air, or oxygen may be blown from a plurality of oxygen blowing portions arranged at appropriate intervals around the solid fuel blowing portion. Further, the position of the solid fuel injection section in the burner radial direction may be deviated to some extent from the center of the burner. In short, pulverized coal and synthetic resin material are blown from or near the center in the burner radial direction. Oxygen is blown from the air.

In the scrap melting method of the above (4), when pulverized coal and synthetic resin material are blown into the pre-combustion chamber of the combustion burner from around oxygen blown from the center in the burner radial direction or the vicinity thereof, Pulverized coal and a synthetic resin material may be blown from a solid fuel blowing portion that annularly surrounds the oxygen blowing portion, or a plurality of solid fuels arranged at appropriate intervals around the oxygen blowing portion. Pulverized coal and a synthetic resin material may be blown from the blowing section. Further, even when oxygen is further blown from the periphery of the solid fuel injection unit, oxygen may be blown from an oxygen injection unit that annularly surrounds the solid fuel injection unit, or the solid fuel injection unit may Oxygen may be blown out from a plurality of oxygen blowing sections arranged at appropriate intervals around the circumference. Further, the position of the oxygen injection section in the burner radial direction (the position of the oxygen injection section inside the solid fuel injection section) may be deviated to some extent from the center of the burner. Oxygen is blown from above, and pulverized coal and a synthetic resin material may be blown from around.

In each of the scrap melting methods described above, the pulverized coal and the synthetic resin material can be blown from separate blowing sections (blowing holes). The particle size and the like of the pulverized coal to be injected are not particularly limited.
Pulverized coal such as that described above is preferred. In addition, the powdery or granular synthetic resin material to be blown is obtained by crushing a lump-shaped (including plate-like) synthetic resin material, or a film-like synthetic resin material is crushed into small pieces. The product obtained by the treatment, the synthetic resin material is once melted or semi-molten, and then processed (pulverized or cut) into powder and granules, and the synthetic resin material is semi-molten and quenched to obtain a powder. Includes those condensed and solidified in the form of particles. The particle size is not particularly limited, and may be relatively coarse, but usually, the particle size is 10 mm or less, preferably 6 mm or less. Further, in the scrap melting methods (3) and (4), since a combustion burner provided with a pre-combustion chamber is used, the synthetic resin material has good fuel properties. It can be charged to the combustion chamber. In addition,
The present invention does not prevent charging of other iron sources and charges together with scrap into the furnace.

[0025]

BEST MODE FOR CARRYING OUT THE INVENTION In the scrap melting method of the present invention, in order to actively obtain high calorie exhaust gas in scrap melting, the fuel ratio is increased by supplying a large amount of solid fuel composed of pulverized coal and synthetic resin material, and the coke ratio is increased. It is assumed that the operation will be performed with the ratio of pulverized coal + synthetic resin material increased. For this reason, in order to efficiently burn the pulverized coal and the synthetic resin material supplied in large quantities and reduce the low-calorie components in the exhaust gas, oxygen (substantially together with the pulverized coal and the synthetic resin material through the tuyere combustion burner is used. Pure oxygen), and the pulverized coal and the synthetic resin material and the oxygen are quickly contacted and mixed to form a combustion gas, and the highly efficient combustion of the pulverized coal and the synthetic resin material (particularly preferably, conditions in the furnace, etc.) Specific combustion and combustion methods that enable stable and highly efficient combustion of pulverized coal and synthetic resin materials that are not affected by
The resulting combustion gas (and gas generated by thermal decomposition of some synthetic resin materials) is discharged to the outside of the furnace without significant secondary combustion, thereby dissolving scrap and collecting high-calorie exhaust gas at low cost. To realize. By supplying synthetic resin into the furnace as part of a heat source and a high calorie exhaust gas source, large-scale processing and effective use of synthetic resin as waste, and further melting of scrap by reducing the amount of pulverized coal are further improved. Realize cost reduction.

The details of the present invention will be described below with reference to the drawings. FIG. 1 is a conceptual diagram showing one configuration example of a shaft furnace used in the scrap melting method of the present invention. A raw material charging device 4 is connected to the upper portion of the furnace top 3 of the shaft furnace 1. Can be completely recovered through the duct 6. In the scrap melting method of the present invention, scrap and coke, which are iron sources, are charged from a furnace top 3 of a shaft furnace 1 by a raw material charging device 4. As the coke, general blast furnace coke (usually, particle size is 20 to 80 mm) can be used. The coke charged into the furnace serves to hold the scrap filled in the furnace and also serves as a part of a heat source for melting the scrap. However, in the present invention, pulverized coal and synthetic resin material blown from the tuyere occupy a larger specific gravity as a heat source.

From the tuyere 2, pulverized coal, synthetic resin material and oxygen are blown into the furnace through a combustion burner. FIG. 2 is an explanatory view showing an example of a method of blowing the pulverized coal and the synthetic resin material and oxygen, and reference numeral 7 denotes a furnace wall. From the combustion burner 8A provided in the tuyere part 2, pulverized coal PC and a granular or flake-shaped synthetic resin material SR from the solid fuel injection part a at or near the center of the burner radial direction, and the surrounding oxygen Oxygen O ₂ (which may be cold oxygen) is blown into the furnace from the blowing part b. At this time, pulverized coal PC and synthetic resin material SR
Is blown into the furnace so that its surroundings are surrounded by oxygen O ₂ , so that the contact of oxygen is extremely good, and the pulverized coal and the synthetic resin material and oxygen are mixed at the tuyere to mix with the pulverized coal and at least the synthetic resin material. Part of the fuel burns rapidly, forming a combustion zone and a raceway at the tuyere. Therefore, a large amount of pulverized coal + synthetic resin material is blown per unit oxygen amount, and [(PC +
Even if SR) / O ₂ ] is sufficiently increased, the pulverized coal and the synthetic resin material are gasified with high efficiency. In addition, a small amount of N ₂ or the like is usually used as a pneumatic gas for blowing the pulverized coal PC and the synthetic resin material.

On the other hand, when pulverized coal and synthetic resin material are blown by a known lance method as shown in FIG.
When hot air or oxygen-enriched air is blown in instead of oxygen gas, sufficient contact between oxygen and pulverized coal and synthetic resin material is not ensured, and pulverized coal and synthetic resin material can be burned with high efficiency. And a large amount of pulverized coal + synthetic resin material cannot be injected. The rapid combustion of pulverized coal and a considerable amount of synthetic resin material blown with oxygen forms a high-temperature combustion zone of about 2,000 ° C at the tuyere tip, and the heat melts the scrap, leaving it as hot metal outside the furnace. Is taken out.
The reducing combustion gas generated by the rapid combustion of pulverized coal and synthetic resin material rises up the shaft furnace while melting and preheating scrap with its sensible heat, and is discharged from the furnace upper part as exhaust gas. The combustion gases are discharged out of the furnace without significant secondary combustion. That is, the combustion gas is not secondary-combusted by supplying air or oxygen-enriched air to the shaft portion unlike the related art.

Further, since synthetic resin materials are inferior in flammability as compared with pulverized coal, it is not usually possible to burn all of the synthetic resin materials in the combustion zone. The high-calorie gas is discharged outside the furnace together with the combustion gas, and is recovered as a fuel gas. As described above, the injection of the synthetic resin material from the solid fuel injection section a may be performed continuously, discontinuously or intermittently. The blowing of the material may be performed together with the blowing of the pulverized coal, or may be performed temporarily instead of the blowing of the pulverized coal. This is the same in the methods shown in FIGS. 3, 9 and 10 described later.

According to the present invention, the gas blown from the tuyere for combustion is oxygen (substantially pure oxygen), and a large amount of pulverized coal can be efficiently gasified by combustion per unit oxygen amount. By burning or thermally decomposing the synthetic resin material blown with the pulverized coal, a high calorie gas can be obtained. Furthermore, by not burning the combustion gas as described above, high levels of CO, H ₂ , and lower hydrocarbons can be obtained. High-calorie exhaust gas (2700 kc) having a very high content of caloric components (and therefore a very low content of CO ₂ and N ₂ )
al / Nm ² or more).

In the present invention, since pulverized coal can be burned with high efficiency, [(PC + SR) / O ₂ ]: 0.7 k
g / Nm ³ or more (preferably 1.0 kg / Nm ³ or more), stable operation is possible, and [(PC + SR)
/ O ₂ ] is the nearly stoichiometric combustion limit [(PC +
SR) / O ₂ ] = about 1.4 kg / Nm ³ pulverized coal and a synthetic resin material can be blown. Therefore, a large amount of high calorie exhaust gas can be obtained by efficiently burning the pulverized coal and the synthetic resin material supplied in large quantities, and the coke ratio is relatively reduced with respect to the pulverized coal ratio + the synthetic resin material ratio. Operation is possible.

FIG. 3 is an explanatory view showing another example of a method of blowing pulverized coal and a synthetic resin material and oxygen in the scrap melting method of the present invention. The combustion burner 8B provided in the tuyere 2 Oxygen O ₂ (which may be cold oxygen) is supplied from the oxygen injection portion b ′ at or near the center of the burner in the radial direction, and pulverized coal PC and the powdery or granular synthetic resin material SR are supplied from the surrounding solid fuel injection portion a. And the oxygen blowing part b around it
Oxygen O ₂ (or cold oxygen) is blown into each furnace from. That is, the pulverized coal PC and the synthetic resin material SR are blown in such a manner that the inside and the outside are sandwiched by oxygen O ₂ . This makes pulverized coal PC and synthetic resin material SR
And oxygen O ₂ are mixed at the tuyere tip, and the pulverized coal and at least part of the synthetic resin material burn rapidly, forming a combustion zone and a raceway at the tuyere tip. In this method, the contact between the pulverized coal and the synthetic resin material and the oxygen is better than in the method of FIG.

FIGS. 4 and 5 show how pulverized coal PC and synthetic resin material SR and oxygen O ₂ are blown in the combustion burner radial direction in the scrap melting method shown in FIG. 2. FIG. The pulverized coal PC and the synthetic resin material SR are blown from the solid fuel blowing portion a at or near the center in the radial direction, and oxygen O ₂ is blown from the oxygen blowing portion b that annularly surrounds the solid fuel blowing portion a. FIG. 5 is an example in which oxygen O ₂ is blown from a plurality of oxygen blowing portions b arranged at appropriate intervals around the solid fuel blowing portion a.

FIGS. 6 to 8 show the manner in which the pulverized coal PC and the synthetic resin material SR and oxygen O ₂ are blown in the combustion burner radial direction in the scrap melting method shown in FIG. 3, of which FIG. Oxygen O ₂ is blown from the oxygen blowing part b ′ at or near the center in the radial direction, and the solid fuel blowing part a is formed to annularly surround the oxygen blowing part b ′.
Pulverized coal PC and synthetic resin material SR are blown from the above, and oxygen O ₂
This is an example in which is blown. FIG. 7 shows the pulverized coal PC and the synthetic resin material SR blown from the solid fuel blowing part a which annularly surrounds the oxygen blowing part b 'at or near the center of the burner radial direction. This is an example in which oxygen O ₂ is blown from a plurality of oxygen blowing portions b arranged at appropriate intervals. FIG. 8 shows a plurality of solid fuel injection parts a arranged at appropriate intervals around the oxygen injection part b 'at or near the center of the burner radial direction.
This is an example in which pulverized coal PC and synthetic resin material SR are blown in from above, and oxygen O ₂ is blown from a plurality of oxygen blowing portions b arranged at appropriate intervals around the solid fuel blowing portion a.

FIGS. 9 and 10 are explanatory views showing another example of a method of blowing pulverized coal and a synthetic resin material and oxygen in the scrap melting method of the present invention. These methods are shown in FIGS. Compared with the scrap melting method shown in the above, there is an advantage that highly efficient combustion of pulverized coal and synthetic resin material can be stably obtained.

In the blowing method shown in FIG. 9, a combustion burner 8C having a pulverized coal pre-combustion chamber 9 is installed in the tuyere 2 inside the burner tip opening 10. In the pre-combustion chamber 9, pulverized coal PC and the synthetic resin material SR are supplied from a solid fuel injection section a disposed at or near the center in the burner radial direction, and oxygen O ₂ (from an oxygen injection section b disposed therearound). Cold oxygen). At this time, since the pulverized coal PC and the synthetic resin material SR are blown in such a manner that their surroundings are surrounded by oxygen O ₂ , the contact between the pulverized coal and the synthetic resin material and oxygen becomes extremely good, and Oxygen is rapidly mixed in the pre-combustion chamber 9 and the pulverized coal and at least a part of the synthetic resin material are rapidly ignited and burned in the pre-combustion chamber 9. The combustion gas thus generated is introduced into the furnace from the burner tip opening 10, and the sensible heat melts the scrap, and is taken out of the furnace as hot metal. Further, as described above, the combustion gas is discharged out of the furnace as a fuel gas together with the gas generated by the thermal decomposition of the unburned synthetic resin material without significant secondary combustion. Therefore, in this method, since the pulverized coal and the synthetic resin material are burned inside the combustion burner, the pulverized coal and the synthetic resin material can be stably burned with high efficiency without being affected by the condition in the furnace.

In the blowing method shown in FIG. 10, a combustion burner 8D having a pulverized coal pre-combustion chamber 9 is installed in the tuyere 2 inside the burner tip opening 10. In the 8D pre-combustion chamber 9, oxygen O ₂ is synthesized from the oxygen injection part b ′ arranged at or near the center in the burner radial direction, and pulverized coal PC is synthesized from the solid fuel injection part a arranged therearound. The resin material SR is further blown with oxygen O ₂ from the oxygen blowing portion b disposed therearound. In this method, since the pulverized coal PC and the synthetic resin material SR are blown in such a manner that the inside and the outside thereof are sandwiched by oxygen O ₂ , the contact state between the pulverized coal and the synthetic resin material and oxygen is compared with the method of FIG. This has the advantage that the combustion efficiency of the pulverized coal and the synthetic resin material is further improved.

Here, the structure of the combustion burner used in the method of FIGS. 9 and 10 will be briefly described.
First, the burner body 12 of the combustion burner 8C shown in FIG.
It is composed of a tubular water cooling jacket 13 and a solid fuel supply pipe 14 and an oxygen supply pipe 15 penetrating the water cooling jacket 13.
3, a solid fuel injection section a and an oxygen injection section b are formed. The pre-combustion chamber 9 is formed in a tubular shape between the burner main body 12 and the burner tip opening 10, and has a nonmetallic refractory 16 lined on its inner wall, as described above. As described above, during use of the burner, the refractory 16 is glowed red, and the radiant heat ignites the pulverized coal and the synthetic resin material supplied into the pre-combustion chamber. Further, in order to secure a gas flow rate of the combustion gas injected into the furnace, the pre-combustion chamber 9 is configured such that the burner tip side is tapered.

Outside the pre-combustion chamber 9, a water cooling jacket 17 is provided.
And a tuyere 18 having a water-cooled structure is provided at the tip of the burner. The tuyere 18 is provided to protect the tip of the burner from the high-temperature atmosphere in the furnace, but may not be provided in some cases. Further, in order to speed up the mixing of the pulverized coal and the synthetic resin material with the oxygen in the pre-combustion chamber 9 and efficiently and rapidly burn the pulverized coal and the synthetic resin material, the solid fuel injection section a and the oxygen injection section b Are configured such that the intersection point p of the extension lines of both hole axes is located at the outlet end of the pre-combustion chamber 9 or inside the burner.

Further, the entire combustion burner is attached to the furnace wall 7 so that its axis has an inclination angle θ such that the tip side of the burner is downward with respect to the horizontal direction. The inclination angle θ is provided in this manner in order to smoothly discharge slag generated by melting ash such as pulverized coal into the furnace from the burner tip opening 10. Is set to a value such that the tapered portion of the inner surface of the pre-combustion chamber is horizontal or its tip side is inclined downward so that the slag in the pre-combustion chamber 9 flows smoothly toward the burner tip opening 10. Is preferred. Further, in the case of the combustion burner shown in FIG. 10, each of the blowing portions a, b, b 'is formed by a leading end opening of the solid fuel supply pipe 14 and the oxygen supply pipes 15, 15' penetrating through the water-cooled jet. ing. Note that the other configuration is the same as that of FIG.

FIGS. 11 and 12 show pulverized coal PC in the combustion burner radial direction in the scrap melting method shown in FIG.
FIG. 11 shows the state of blowing the synthetic resin material SR and oxygen O _2, of which FIG. This is an example in which oxygen O ₂ is blown from an oxygen blowing portion b which annularly surrounds a fuel blowing portion a. FIG. 12 is arranged at appropriate intervals around a solid fuel blowing portion a. This is an example in which oxygen O ₂ is blown from a plurality of oxygen blowing sections b.

FIGS. 13 to 15 show the manner of blowing the pulverized coal PC and the synthetic resin material SR and oxygen O _{2 in} the radial direction of the combustion burner in the scrap melting method shown in FIG. 10, and FIG. Oxygen O ₂ is blown from the oxygen blowing part b ′ at the radial center or in the vicinity thereof,
The pulverized coal PC and the synthetic resin material SR are blown from the solid fuel blowing portion a surrounding the oxygen blowing portion b 'in a ring shape, and oxygen O ₂ is blown from the oxygen blowing portion b surrounding the circumference in a ring shape. This is an example. FIG. 14 shows a pulverized coal PC from a solid fuel injection part a which annularly surrounds an oxygen injection part b 'at or near the center of the burner radial direction.
This is an example in which a synthetic resin material SR is blown, and oxygen O ₂ is blown from a plurality of oxygen blowing portions b arranged at appropriate intervals around the solid fuel blowing portion a. FIG. 15 shows that the pulverized coal PC and the synthetic resin material SR are blown from a plurality of solid fuel blowing portions a arranged at appropriate intervals around the oxygen blowing portion b ′ at or near the burner radial center. This is an example in which oxygen O ₂ is blown from a plurality of oxygen blowing sections b arranged at appropriate intervals around a solid fuel blowing section a.

In the combustion burner provided with the pre-combustion chamber 9 as shown in FIGS. 9 and 10, instead of or together with the blowing of the synthetic resin material in the form of powder or granules, the synthetic resin material in the form of a lump is formed. The material can be charged into the pre-combustion chamber 9 and at least a part thereof can be burned. In this case, the massive synthetic resin material is charged into the pre-combustion chamber 9 through a charging port separately provided in the combustion burner. In order to ignite and burn the pulverized coal and the synthetic resin material in the pre-combustion chamber 9, an ignition burner (not shown) using oil, LPG, or the like as a fuel can be used at all times. The burner (pilot burner) is used to preheat the interior of the burner or ignite and burn pulverized coal, etc., only in the early stages of operation. Ignition can also be used.

FIG. 16 shows the burning rate of pulverized coal at [PC / O ₂ ] = 1.2 kg / Nm ³ when the pulverized coal was rapidly burned by the method shown in FIG. 2 and the method shown in FIG. It shows the results of examination over time. In this test, synthetic resin material was blown in only a small amount in order to check the combustion rate of pulverized coal. According to FIG. 16, a high pulverized coal combustion rate is obtained as a whole by any of the methods. However, in the method shown in FIG. 2, the combustion rate tends to fluctuate slightly with time. This is because the state of the charge (for example, a coke packed bed) in the combustion space at the tuyere tip fluctuates. It is thought to be due to the effect on flammability. On the other hand, according to the method shown in FIG. 9, most of the supplied pulverized coal is gasified by combustion in the pre-combustion chamber, so that the combustion of the pulverized coal is hardly affected by the condition in the furnace and the like. A stable level of pulverized coal combustion rate is obtained.

FIG. 17 shows ideal combustion conditions of pulverized coal near the tuyere for the method shown in FIG. 2 and the method shown in FIG. According to this, in the case of the method of FIG. 2, a combustion zone is formed at the tuyere tip, and a so-called raceway is formed outside the combustion zone. In contrast, FIG.
In the case of the method (1), almost all of the oxygen blown into the pre-combustion chamber 9 is rapidly consumed in the pre-combustion chamber 9, and as a result, the combustion gas of pulverized coal (CO ₂ in the combustion burner) Is generated, but CO ₂ in the combustion gas introduced into the furnace is extremely small, and most of the CO is introduced. Thereby, the combustion zone (oxidation zone) as shown in FIG. 2 is hardly formed at the tuyere tip, and only the raceway is formed.

As described above, according to the method of the present invention, a large amount of pulverized coal + synthetic resin material can be efficiently combusted and gasified.
For this reason, it is possible to operate the coke ratio relatively lower than the pulverized coal ratio and the synthetic resin material ratio, but particularly in the method shown in FIGS. 9 and 10, most of the supplied oxygen is contained in the pre-combustion chamber. Due to rapid consumption, little or no, if any, combustion zone is formed at the tuyere tip. For this reason, consumption (combustion) of coke at the tuyere tip is suppressed, and this also contributes to a reduction in coke ratio.

Next, the operation and effect of blowing the pulverized coal + synthetic resin material from the tuyere in the method of the present invention will be described in detail. In the present invention, the synthetic resin material is used as a part of a heat source and a high-calorie exhaust gas source by blowing or charging the synthetic resin material through a combustion burner provided in the tuyere in a specific manner. Such a synthetic resin material can be used by blowing the synthetic resin material together with pulverized coal (preferably, a relatively large amount of pulverized coal). It depends largely on what you take.

That is, when a relatively large amount of synthetic resin material is generally blown into the shaft furnace from the tuyere, the following problems can be considered. (1) If a sufficient amount of the injected synthetic resin material does not burn rapidly at the tuyere or tuyere, the unburned synthetic resin material fuses in the bed coke and significantly increases the air permeability in the furnace. Hinders the operation of the shaft furnace as a result. (2) It is said that the ratio of vinyl chloride in synthetic resin material as general waste and industrial waste is about 20%, but when such synthetic resin material is blown into the furnace, A large amount of HCl is generated by the combustion of the vinyl chloride material,
This is mixed into the exhaust gas and significantly lowers the quality as a fuel gas. (3) The unburned synthetic resin material is once thermally decomposed in the furnace, and the decomposed products (gases) react secondarily at the furnace top and in the exhaust gas pipe system to generate tar precursors. The resulting tar-like substance adheres and accumulates on the inner surface of the exhaust gas pipe to block the pipe.

However, according to the scrap melting method of the present invention, the synthetic resin material can be blown into the furnace without causing the above-mentioned problems. That is, first, regarding the above point (1), the present invention employs a special blowing method (the blowing method based on the above-described configuration) that enables highly efficient combustion of pulverized coal, and the synthetic resin material. Basically, it is burned efficiently by being blown by this method, so that a considerable amount of the blown synthetic resin material burns rapidly at the tuyere or tuyere tip. For this reason,
The proportion of unburned synthetic resin material remaining in the lower part of the furnace is reduced, and there is no problem that the synthetic resin material is fused in the coke bed and impairs the air permeability in the furnace.

Regarding the above point (2), in the method of the present invention, the HCl concentration in the exhaust gas is effectively reduced for the following reasons. First, in order to reduce the concentration of HCl in the exhaust gas, CaO, Na ₂ O, F contained in the dust in the exhaust gas are used.
It is most effective to cause the HCl capturing component such as e to capture HCl. According to the method of the present invention, pulverized coal can be burned with high efficiency. Therefore, even when a large amount of pulverized coal is blown, the amount of unburned char contained in the exhaust gas is small for the amount of the blown coal. The amount of dust in the 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 injected, the amount of the HCl trapping component in the furnace top gas is relatively large in the method of the present invention in which a large amount of pulverized coal is blown. H due to HCl trapping component
High Cl capture rate.

As described above, in the method of the present invention, since the combustion efficiency of pulverized coal is high, the amount of unburned char in the exhaust gas is relatively small in spite of the amount of pulverized coal injected. Contains a considerable amount of unburned char. Since the unburned char has a function of strongly and strongly adsorbing (physical adsorption) HCl in the exhaust gas, the concentration of HCl in the gas is reduced by contact with the exhaust gas for a very short time.
HCl physically adsorbed on the surface of the unburned char gradually removes HCl trapping components (CaO, Na) contained in the dust.
₂ O, and reacted with Fe, etc.) are secured to the dust. In other words, the HCl physically adsorbed on the unburned char is absorbed by the HCl trapping component by a chemical reaction over time, and is finally fixed as chlorides such as CaCl ₂ , NaCl, and FeCl _2. . Then, these chlorides are separated and removed from the exhaust gas as a part of dust.

In particular, according to the method of the present invention, since no significant secondary combustion is performed at the shaft portion and the furnace top, unburned char to be adsorbed with HCl is not lost through the furnace shaft portion and the furnace top. There are advantages. Therefore, the adsorption of HCl by the unburned char is effectively performed, and
HCl once adsorbed on 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, the amount of synthetic resin material blown (more precisely, the amount of vinyl chloride material blown) must be adjusted. It is preferable to ensure that the amount of HCl trapping component and the amount of unburned char are ensured, and therefore, a considerable amount of pulverized coal is blown in accordance with the blown amount of the synthetic resin material. Specifically, 1/1 of the blowing amount of the synthetic resin material
It is preferable to blow pulverized coal having a weight of 0 or more, and it is preferable that the blowing amount (weight) of the pulverized coal is equal to or larger than the blowing amount of the vinyl chloride material.

Next, regarding point (3), since a relatively large amount of pulverized coal is blown from the tuyere in the method of the present invention, usually, the furnace top gas contains hydrogen at a concentration of 5% or more. It is.
Since the decomposition product of the synthetic resin material is stabilized by the presence of the hydrogen, the decomposition product is prevented from secondary reacting with each other to generate a tar precursor, thereby preventing trouble such as pipe blockage. It is possible to prevent the generation of a tar-like or wax-like substance which causes a problem. As described above, the problem that becomes a major bottleneck when the synthetic resin material is blown into the furnace in the molten iron manufacturing method does not cause any problem according to the scrap melting method of the present invention. Therefore, the in-furnace injection of the synthetic resin material in the melting of scrap has the purpose of performing low-cost production of hot metal and high calorie exhaust gas using scrap and pulverized coal and synthetic resin material as main raw materials. It is no exaggeration to say that the method of the present invention, which can be achieved by the above-mentioned means under an operation at a high fuel ratio by blowing a large amount of synthetic resin material, becomes possible for the first time.

As described above, the present invention is based on the premise that the fuel ratio is higher than in the conventional method and that a large amount of pulverized coal + synthetic resin material is blown. On a base, fuel ratio: 300 kg / t · pig or more, pulverized coal ratio (kg / t ·
pig) and the weight ratio of the synthetic resin material ratio (kg / t · pig) and the coke ratio (kg / t · pig) charged into the furnace top [(pulverized coal ratio + synthetic resin material ratio) / coke ratio]: 1 0.0 or more, thereby making it possible to produce hot metal with high efficiency and to stably supply a large amount of high calorie exhaust gas as described above. The upper limit is determined by the operation rate, the fuel cost, the required recovered gas balance, and the like. In general, the fuel ratio is 500 kg / t · pig, [(pulverized coal ratio + synthetic resin ratio) / coke ratio]: 2. It is considered that about 5 is a substantial upper limit.

As described above, in the present invention, since it is assumed that the operation is performed with the fuel ratio relatively increased as compared with the conventional method, the fuel cost itself becomes higher as compared with the conventional method. By using a lot of pulverized coal, which is much cheaper than coke, and using a considerable amount of synthetic resin material, the coke ratio can be relatively reduced,
Moreover, since a large amount of high calorie exhaust gas having high utility value can be produced, the production and operation costs can be reduced as a whole as compared with the conventional method.
Simultaneously injecting pulverized coal, synthetic resin material and oxygen in a manner as in the present invention also helps to ensure the yield and quality of the hot metal. That is, assuming a system in which only coke is charged into the furnace as a heat source and only oxygen is blown from the tuyere, an oxygen zone is formed in the tuyere tip long in the depth direction, and hot metal flowing in the vicinity thereof is easily oxidized. For,
Iron migrates into the slag as FeO to lower the yield of iron, and the quality of the hot metal is degraded by suspending the oxide in the components of the hot metal.

On the other hand, in the method of the present invention, the pulverized coal and the synthetic resin material rapidly consume oxygen at the tuyere tip, so that the oxidation zone is sufficiently small. No. In particular, in the method of the present invention shown in FIGS. 9 and 10, pulverized coal and the synthetic resin material rapidly consume oxygen in the pre-combustion chamber, so that almost no or no combustion zone is formed at the tuyere tip. Even if it is performed, it is formed only in a very limited narrow area, and therefore, the oxidation of the molten iron slag as described above hardly causes a problem. The action described above is particularly effective when [(PC + SR) / O ₂ ] is 0.7 kg /
Effectively obtained by setting Nm ³ or more, more preferably 1.0 or more.

In the method of the present invention, the scrap is smoothly dissolved by blowing the combustion gas obtained by rapidly burning the pulverized coal and the synthetic resin material to the tuyere. No special casting coke is required for distribution control. In the method of the present invention, a coke is required to form a raceway below the melting zone and hold the filled scrap, but coke for a blast furnace can be used for this. In addition, the slag mainly composed of coal ash generated by the combustion and gasification of pulverized coal is easily melted, separated from the hot metal at the lower part of the furnace, accumulates at the upper part, and easily discharged outside the furnace together with tapping. It does not hinder operation. In the method of the present invention, in addition to blowing the pulverized coal and the synthetic resin material and oxygen by the combustion burner, steam, nitrogen, or the like for adjusting the combustion temperature can be appropriately blown as a coolant through the same combustion burner or the like.

In the present invention, the purity of the oxygen gas blown from the combustion burner is preferably as high as possible, but the purity of the oxygen gas generally used for industrial purposes is 99%.
% (Usually, the purity of commercially available industrial oxygen gas is about 99.8% to 99.9%, and the purity of oxygen gas obtained from an oxygen plant in a steel mill is about 99.5%) And this degree of purity is sufficient. Further, from the viewpoint of the function and effect obtained by the present invention, oxygen gas having a purity of less than 95% cannot sufficiently ensure contact between the pulverized coal and synthetic resin material to be blown and oxygen.
The combustion efficiency of the pulverized coal and the synthetic resin material deteriorates, and the low-calorie gas component in the exhaust gas also increases, making it difficult to achieve the object of the present invention. Therefore,
In the present invention, the oxygen blown from the tuyere is 95% pure.
% Or more of oxygen gas.

[0059]

【Example】

Example 1 A test furnace for scrap melting having a tuyere of the structure shown in FIG. 2 in the furnace body of FIG. 1 (furnace inner volume: 2.5 m ³ ,
A test furnace for scrap melting having a tuyere of the structure shown in FIG. 3 in the furnace body of FIG. 1 (furnace volume: 2.5 m ³ , pig iron production: 10 t / day); A scrap melting test furnace having a tuyere having the structure shown in FIG. 9 in the furnace body of FIG. 1 (furnace volume: 2.5 m ² , pig iron production: 10 t)
/ Day), and [PC / O ₂ ] was changed by the method of the present invention to dissolve the scrap and produce hot metal. In the present embodiment, pulverized coal and powdery synthetic resin material and room temperature oxygen (cold oxygen) are blown into the furnace from the combustion burner or into the pre-combustion chamber of the combustion burner, and the combustion temperature at the tuyere tip is set to 2000.
Nitrogen and / or steam were blown as a cooling agent to adjust to ° C. In this example, in order to examine the combustibility of the pulverized coal, the injection amount of the synthetic resin material was suppressed to an extremely small amount, and the weight ratio of synthetic resin material / (synthetic resin material ratio + pulverized coal) was 0.1.
The range was from 01 to 0.5.

As a comparative method, scrap was melted by changing the [PC / O ₂ ] using a test furnace having the tuyere shown in FIG. 19 in the furnace body of FIG. 1 to produce hot metal. FIG.
Is a method in which pulverized coal is blown into oxygen-enriched hot air through a lance 20 based on a known cupola method.
[PC / O ₂ ] was changed by adjusting the amount of oxygen enrichment and the amount of pulverized coal using hot air at ℃. In this example, pulverized coal having a particle size of 74% or less and 75% and having the industrial analysis values shown in Table 1 was used for blowing, and blast furnace coke was used as coke.

In order to check the pulverized coal injection limit in the method of the present invention and the comparative method, dust in the furnace top gas was sampled sequentially, and the C concentration (%) in the dust was measured. FIG. 18 shows the result. FIG. 18 shows the relationship between the ratio [PC / O ₂ ] of the input pulverized coal amount PC (kg / h) and the oxygen flow rate O ₂ (Nm ³ / h) and the C concentration in the furnace-top dry dust (the blowing of synthetic resin material). (PC / O ₂ ] was evaluated because the amount of inclusion was extremely small.) In the comparative method, the value of [PC / O ₂ ] was 0.7 kg.
When it exceeds / Nm ³ , the C concentration in the dust at the furnace top sharply increases. This indicates that when [PC / O ₂ ] is in this region, the pulverized coal cannot be sufficiently burned at the tuyere tip and is discharged without burning from the furnace top. This means that it is not fully utilized as fuel.

On the other hand, in the method of the present invention according to the method shown in FIG. 2, the C concentration in the dry gas at the furnace top is low until [PC / O ₂ ] is in the vicinity of 1.4 kg / Nm ^3. It turns out that it is burned and burned in the furnace.
Further, it can be seen that pulverized coal burns more efficiently in the method of the present invention according to the method of FIG. 3, and further, pulverized coal burns most efficiently in the method of the present invention according to the method of FIG. Incidentally, [PC / O _2] is almost the upper limit is stoichiometrically 1.4 kg / Nm ^3, the present invention method [PC / O _2]:
The rapid increase in the C concentration in the furnace top dry gas at around 1.4 kg / Nm ³ does not indicate the limit of the method of the present invention. As is clear from this embodiment, according to the method of the present invention, pulverized coal and oxygen blown from the tuyere are rapidly mixed at the tuyere tip and the pulverized coal is rapidly burned, so that [PC / O ₂ ] Even if p is sufficiently increased, pulverized coal can be efficiently burned and gasified. Further, it was confirmed that the method of the present invention did not hinder the melting of scrap and the production of hot metal.

[0063]

[Table 1]

[Example 2] A test furnace having the tuyere shown in Fig. 2 as in Example 1, a test furnace having the tuyere shown in Fig. 3, and a test having the tuyere shown in Fig. 9 Scrap was melted by using a furnace and a test furnace having a tuyere shown in FIG. 19, respectively, to produce hot metal. Example 1 pulverized coal and coke
The same material as described above was used, and a powdery synthetic resin material having an average particle size of 0.2 to 1 mm was used. In this example, in some comparative examples, air for secondary combustion was introduced into the shaft portion, and the combustion gas was subjected to secondary combustion. Tables 2 to 10 show the production conditions and the results of each example.

In Tables 2 to 10, No. No. 1 is an operation example (pulverized coal ratio: 0) in which pulverized coal and synthetic resin material were not blown (only oxygen was blown from the tuyeres) and all heat sources were coke (pulverized coal ratio: 0). 2-No. No. 4 blows pulverized coal and a small amount of powdery synthetic resin material together with oxygen from a combustion burner. 2 → No. 4 is an operation example in which the pulverized coal ratio + the synthetic resin material ratio was increased in the order of 4. No. which does not blow pulverized coal and synthetic resin material. In No. 1, Fe in the slag was affected by the expansion of the oxidation zone in the raceway.
O becomes high, resulting in a decrease in quality of hot metal and a decrease in iron yield. In addition, this No. In the case of No. 1, since the heat source is entirely coke, the production cost is naturally high.

No. No. 2 has pulverized coal injected but has a low [(PC + SR) / O ₂ ]. FeO in the slag is high, though not as much as one. Further, in this operation example, [(pulverized coal ratio + synthetic resin material ratio) / coke ratio] is about 0.36, and there is a problem in the production cost because the coke ratio is relatively high. On the other hand, No. 3, No. In No. 4, FeO in the slag was low, and the quality of the hot metal and the iron yield were good. In addition, these Nos. 3, No. In No. 4, despite the fact that a large amount of pulverized coal + synthetic resin material exceeding the coke ratio was injected, their combustion was performed efficiently, so that 2700 kca
A large amount of high calorie exhaust gas of 1 / Nm ³ or more is obtained.

No. 5, No. Reference numeral 6 denotes a test furnace having a tuyere having the structure shown in FIG. 7, No. 8 uses a test furnace provided with a tuyere of the structure shown in FIG.
The above No. 3, No. 4 is an operation example in which oxygen, pulverized coal, and a small amount of a granular synthetic resin material were blown from a combustion burner under conditions substantially corresponding to No. 4.
3, No. As compared with No. 4, the flammability of the pulverized coal and the synthetic resin material was further enhanced, and as a result, the coke ratio was slightly reduced, and the amount of furnace dust generated was further reduced. No. 9-No. 1
No. 5 shows the ratio of synthetic resin material blown from the tuyere. 3, N
o. No. 4 and more. 9 → No. These are operation examples in which the ratio of the vinyl chloride resin contained in the synthetic resin material was increased in the order of 15, and the HCl concentration in the exhaust gas was kept low in each case.

No. 16-No. Reference numeral 18 denotes a test furnace having a tuyere having the structure shown in FIG. 19-No.
No. 21 uses a test furnace having a tuyere having the structure shown in FIG. 10, No. 12, No. This is an operation example in which the operation was performed under conditions substantially corresponding to No. 14, and in each of the operation examples, the HCl concentration in the exhaust gas was kept low. No. 22-No. No. 24 is an operation example in which the synthetic resin material ratio was greatly increased with respect to the pulverized coal ratio. The concentration of HCl in the exhaust gas is higher than that of Nos. 10 to 21.

No. Reference numeral 25 denotes an operation example in which pulverized coal, an appropriate amount of synthetic resin material (hereinafter, referred to as pulverized coal, etc.) and oxygen are blown using a conventional blowing tuyere, and [(PC + SR) ) / O ₂ ], which requires a large amount of coke as compared with pulverized coal and the like, and the production cost is high. Further, since contact between pulverized coal or the like at the tuyere tip and oxygen is not sufficiently ensured, the content of FeO in the slag is high, and the quality of the hot metal is reduced and the iron yield is reduced.

No. Reference numeral 26 denotes an operation example in which oxygen-enriched air is blown together with pulverized coal or the like using a conventional blowing tuyere. In this operation example, in addition to using the conventional blowing tuyere, Since oxygen-enriched air is used as the gas, sufficient contact between oxygen and pulverized coal cannot be ensured, and the combustion efficiency of pulverized coal is reduced by N
o. Therefore, the production cost is high because the coke ratio must be increased. In addition, since oxygen-enriched air (66% O ₂ ) is used, the calorie of the exhaust gas is low (less than 2500 kcal / Nm ³ ), and the contact between oxygen and pulverized coal is sufficient as described above. , The FeO in the slag is high, resulting in a decrease in the quality of the hot metal and a decrease in the iron yield.

No. Reference numeral 27 denotes an operation example in which oxygen-enriched air is blown together with pulverized coal and the like and air for secondary combustion is introduced into the shaft portion using a conventional blowing tuyere. Although the fuel ratio can be lower than that of No. 26, For the same reason as in No. 26, the combustion efficiency of pulverized coal or the like is low, and the production cost is high because the coke ratio is high. Further, since oxygen-enriched air (66% O ₂ ) is used and the combustion gas generated by the combustion of pulverized coal or the like is subjected to secondary combustion, the calories of the exhaust gas are extremely low (less than 1800 kcal / Nm ³ ). . In addition, No. 26
In the same manner as described above, since sufficient contact between oxygen and pulverized coal or the like is not ensured, FeO in the slag is high, and the quality of the hot metal is reduced and the iron yield is reduced.

No. An operation example 28 employs a tuyere injection method corresponding to the method of the present invention and blows oxygen-enriched air from around pulverized coal or the like. In this operation example, oxygen-enriched air is blown gas. Due to its use, sufficient contact between oxygen and pulverized coal or the like cannot be ensured, so that the combustion efficiency of the pulverized coal or the like is low, and therefore the coke ratio must be increased, resulting in high production costs. Also, since oxygen-enriched air (69% O ₂ ) is used, the calories of the exhaust gas are also low (less than 2400 kcal / Nm ³ ).
Further, since oxygen-enriched air is used, contact between oxygen and pulverized coal is not sufficiently ensured. 3, No. 4 is higher than that of No. 4 and lowers the quality of hot metal and lowers the yield.

No. Reference numeral 29 denotes an operation example in which a tuyere injection method corresponding to the method of the present invention is employed, oxygen-enriched air is blown from around pulverized coal or the like, and air for secondary combustion is introduced into the shaft portion. In the operation example, No. 28
Although the fuel ratio can be lower than that of For the same reason as in No. 28, the combustion efficiency of pulverized coal and the like is low, and the production cost is high because the coke ratio is high. Also, since oxygen-enriched air (62% O ₂ ) is used and the combustion gas generated by the combustion of pulverized coal or the like is subjected to secondary combustion, the calories of the exhaust gas are extremely low (less than 1800 kcal / Nm ³ ). . In addition, No. As in the case of No. 28, the contact between oxygen and pulverized coal is not sufficiently ensured. 3, N
o. 4 compared to No. 4 and lowers the quality of the hot metal and lowers the iron yield.

No. 30 and No. No. 31 is an example of operation with a low fuel ratio. Numeral 30 denotes an operation example in which a tuyere blowing method corresponding to the method of the present invention is adopted, and oxygen-enriched air is blown from around pulverized coal or the like. In this operation example, since oxygen-enriched air is used as the blowing gas, the contact between oxygen and pulverized coal cannot be sufficiently secured,
For this reason, the combustion efficiency of pulverized coal or the like is low, and the coke ratio must be increased, so that the production cost is high. In addition, since oxygen-enriched air (63% O ₂ ) is used, the calories of the exhaust gas are low (2300 kcal / N
m ³ ), and the amount of exhaust gas is small due to the operation at a low combustion ratio. In addition, since oxygen-enriched air is used, sufficient contact between oxygen and pulverized coal or the like cannot be ensured. 3, No. 4 is higher than that of No. 4 and lowers the quality of hot metal and lowers the yield.

No. Reference numeral 31 denotes an operation example in which a tuyere blowing method corresponding to the method of the present invention is employed, oxygen-enriched air is blown from around pulverized coal or the like, and air for secondary combustion is introduced into the shaft portion. In the operation example, No. 30
Although the fuel ratio can be lower than that of For the same reason as in the case of 30, the combustion efficiency of pulverized coal or the like is low, and the production cost is high because the coke ratio is high. Further, since oxygen-enriched air (63% O ₂ ) is used and the combustion gas generated by the combustion of pulverized coal or the like is subjected to secondary combustion, the calories of the exhaust gas are extremely low (less than 1800 kcal / Nm ³ ). Further, since the operation is performed at a low combustion ratio, the amount of exhaust gas is small.
In addition, No. As in the case of No. 30, the contact between oxygen and pulverized coal or the like is not sufficiently ensured. 3,
No. 4 compared to No. 4 and lowers the quality of the hot metal and lowers the iron yield.

No. 32, no. Reference numeral 33 denotes an operation example in which pulverized coal and a relatively large amount of synthetic resin material are blown from the tuyere using a tuyere blowing method corresponding to the method of the present invention, and air for secondary combustion is introduced into the shaft. However, in these operation examples, the unburned char in the exhaust gas is lost due to the secondary combustion. As a result, most of the HCl adsorbed on the unburned char is desorbed and transferred again into the exhaust gas.
The concentration is remarkably high.

[0077]

[Table 2]

[0078]

[Table 3]

[0079]

[Table 4]

[0080]

[Table 5]

[0081]

[Table 6]

[0082]

[Table 7]

[0083]

[Table 8]

[0084]

[Table 9]

[0085]

[Table 10]

[0086]

As described above, according to the present invention, not only can molten iron be efficiently produced by melting scrap, but also a large amount of high-calorie exhaust gas having high utility value as a fuel gas can be obtained. In addition, inexpensive pulverized coal obtained by pulverizing thermal coal can be used as the main heat source, synthetic resin material can be used as a part of the heat source and high calorie exhaust gas source, and [(PC + SR) / O ₂ ] can be increased. Since it is possible to burn a large amount of pulverized coal and synthetic resin material with a small amount of oxygen and to carry out it with simple equipment, production of scrap, hot metal and gas for high calorie fuel using pulverized coal and synthetic resin material as the main raw materials. It can be implemented at low cost. In particular, in consideration of the fact that the ratio of pulverized coal + the ratio of synthetic resin material can be increased and that high-value calorie exhaust gas with high utility value can be produced in large quantities, the production and operation costs are considerably lower than those of the prior art. In addition, there is an excellent effect that large-scale processing and effective utilization of synthetic resin as waste can be achieved.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram showing an example of a configuration of a shaft furnace used for performing a scrap melting method of the present invention.

FIG. 2 is an explanatory view showing one configuration example (cross-sectional structure) of a tuyere portion of a shaft furnace and a method of blowing pulverized coal, a synthetic resin material, and oxygen according to the method of the present invention.

FIG. 3 is another structural example of a tuyere portion of a shaft furnace (cross-sectional structure).
And an explanatory view showing a method of blowing pulverized coal and a synthetic resin material and oxygen according to the method of the present invention

FIG. 4 is an explanatory view showing an example of a mode of blowing pulverized coal, a synthetic resin material, and cold oxygen O ₂ in the burner radial direction in the combustion burner shown in FIG. 2;

FIG. 5 is an explanatory view showing another example of the mode of blowing the pulverized coal, the synthetic resin material, and the cold oxygen O ₂ in the burner radial direction in the combustion burner shown in FIG. 2;

FIG. 6 is an explanatory view showing an example of a mode of blowing pulverized coal, a synthetic resin material, and cold oxygen O ₂ in the burner radial direction in the combustion burner shown in FIG. 3;

FIG. 7 is an explanatory view showing another example of the mode of blowing the pulverized coal, the synthetic resin material, and the cold oxygen O ₂ in the burner radial direction in the combustion burner shown in FIG. 3;

FIG. 8 is an explanatory view showing another example of a mode of blowing pulverized coal, a synthetic resin material, and cold oxygen O ₂ in the burner radial direction in the combustion burner shown in FIG. 3;

FIG. 9 shows another configuration example (cross-sectional structure) of the tuyere portion of the shaft furnace.
And an explanatory view showing a method of blowing pulverized coal and a synthetic resin material and oxygen according to the method of the present invention

FIG. 10 is an explanatory view showing another configuration example (cross-sectional structure) of a tuyere portion of a shaft furnace and a method of injecting pulverized coal, a synthetic resin material, and oxygen according to the method of the present invention.

11 is an explanatory diagram showing an example of a mode of blowing pulverized coal, a synthetic resin material, and cold oxygen O ₂ in the burner radial direction in the combustion burner shown in FIG. 9;

FIG. 12 is an explanatory view showing another example of the mode of blowing the pulverized coal, the synthetic resin material, and the cold oxygen O ₂ in the burner radial direction in the combustion burner shown in FIG. 9;

13 is an explanatory diagram showing an example of a mode of blowing pulverized coal, a synthetic resin material, and cold oxygen O ₂ in the burner radial direction in the combustion burner shown in FIG. 10;

FIG. 14 is an explanatory diagram showing another example of the mode of blowing pulverized coal, a synthetic resin material, and cold oxygen O ₂ in the burner radial direction in the combustion burner shown in FIG. 10;

FIG. 15 is an explanatory diagram showing another example of the mode of blowing pulverized coal, a synthetic resin material, and cold oxygen O ₂ in the burner radial direction in the combustion burner shown in FIG. 10;

FIG. 16 is a graph showing the pulverized coal combustion rate over time when pulverized coal and a synthetic resin material are blown with oxygen according to the method of the present invention.

FIG. 17 is an explanatory diagram showing an ideal combustion situation near the tuyere when oxygen is blown into pulverized coal and a synthetic resin material according to the method of the present invention.

FIG. 18 shows the amount of pulverized coal pulverized PC (kg / h) and the oxygen flow rate in Example 1 regarding the method of the present invention of the injection method according to FIGS. 2, 3 and 9 and the comparison method of the injection method according to FIG. Graph showing the relationship between the ratio [PC / O ₂ ] of O ₂ (Nm ³ / h) and the C concentration in the dry gas at the furnace top.

FIG. 19 is an explanatory view showing a cross-sectional structure of a tuyere portion of a conventional method.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... shaft furnace, 2 ... tuyere part, 3 ... furnace top part, 4 ... raw material charging apparatus, 5 ... opening / closing apparatus, 6 ... duct, 7 ... furnace wall, 8A,
8B, 8C, 8D: Combustion burner, 9: Pre-combustion chamber, 10 ...
Burner tip opening, 12: burner body, 13: water-cooled jet, 14: solid fuel supply pipe, 15, 15 ': oxygen supply pipe, 16: refractory, 17: water-cooled jet, 18: tuyere,
20: lance, a: solid fuel charcoal blowing section, b, b '... oxygen blowing section, p: intersection

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Takanori Inokuchi 1-1-2 Marunouchi, Chiyoda-ku, Tokyo Inside Nippon Kokan Co., Ltd. (72) Inventor Tatsuro Ariyama 1-1-2 Marunouchi, Chiyoda-ku, Tokyo Japan JP Steel Co., Ltd. JP-A-63-195207 (JP, A) JP-A-49-7114 (JP, A) JP-A-61-69608 (JP, U) JP-A-7-502568 (JP, A) JP-A 62-502202 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C21B 11/02 C21B 5/00 319 C21B 7/00 309

Claims (13)

(57) [Claims] Claims: 1. An iron source scrap in a shaft furnace.
Charge the coke and use the combustion burner provided at the tuyere
IsPulverized coal ratio PC (kg / t · pig) and synthetic resin material ratio S
R (kg / t · pig) and oxygen flow rate O ₂ (Nm ³ / T ・ pi
g) [(PC + SR) / O ₂ Is 0.7 kg / N
m ³ Under the conditions abovePulverized coal, granular or fine
Blowing synthetic resin and oxygen into the furnaceFuel ratio 3
More than 00 kg / t · pig
Pulverized coal ratio (kg / t-pig) and synthetic resin material ratio (kg / t
・ Pig) and the coke ratio charged into the furnace top (kg / t ・ pig)
Weight ratio [(pulverized coal ratio + synthetic resin ratio) / coke ratio]
Melting performed under operating conditions with
The solution The pulverized coal, powdery or flaky synthetic resin material and oxygen
of When blowing,Burner with pulverized coal and synthetic resin material
Blow in from the radial center or its vicinity,
Pulverized coal and synthetic resin material and acid
Mixed with pulverized coal and at least synthetic resin
Part of the material is burned rapidly in the combustion zone formed at the tuyere tip,
Hot metal is produced by melting scrap with the sensible heat of this combustion gas
Along withSaidThe combustion gases are significantly burned in the furnace
Characterized in that it is recovered as fuel gas without
Scrap dissolution method. 2. A shaft furnace having a scrap as an iron source in a shaft furnace.
Charge the coke and use the combustion burner provided at the tuyere
IsPulverized coal ratio PC (kg / t · pig) and synthetic resin material ratio S
R (kg / t · pig) and oxygen flow rate O ₂ (Nm ³ / T ・ pi
g) [(PC + SR) / O ₂ Is 0.7 kg / N
m ³ Under the conditions abovePulverized coal, granular or fine
Blowing synthetic resin and oxygen into the furnaceFuel ratio 3
More than 00 kg / t · pig
Pulverized coal ratio (kg / t-pig) and synthetic resin material ratio (kg / t
・ Pig) and the coke ratio charged into the furnace top (kg / t ・ pig)
Weight ratio [(pulverized coal ratio + synthetic resin ratio) / coke ratio]
Melting performed under operating conditions with
The solution The pulverized coal, powdery or flaky synthetic resin material and oxygen
of When blowing,Burner radial center or
Oxygen is blown from the vicinity of
Inject charcoal and synthetic resin material and further oxygen from around
Blow to mix oxygen with pulverized coal and synthetic resin material.
By using pulverized coal and at least a part of synthetic resin material
Rapid combustion in the combustion zone formed earlier, this combustion gas
Melting scrap with sensible heat to produce hot metal,
SaidCombustion gas without significant secondary combustion in the furnace
Scrap melting characterized by being recovered as feed gas
solution. 3. The blowing of the synthetic resin material by the combustion burner is performed discontinuously or intermittently, and the blowing of the synthetic resin material is performed together with the blowing of the pulverized coal or temporarily instead of the blowing of the pulverized coal. 3. The method according to claim 1, wherein the scrap is dissolved. 4. A pre-combustion chamber is provided inside the burner tip opening.
A shaft furnace equipped with a burned combustion burner at the tuyerefor
In the shaft furnaceScrap and coke as iron sources
And in the pre-combustion chamber of the combustion burnerPulverized coal ratio P
C (kg / t · pig) and synthetic resin material ratio SR (kg / t
・ Pig) and oxygen flow rate O ₂ (Nm ³ / T · pig)
[(PC + SR) / O ₂ Is 0.7 kg / Nm ³ And above
Under such conditionsInject pulverized coal and oxygen
Inject granular, strip-shaped or massive synthetic resin material
Or charge,Fuel ratio of 300kg / t-pig or more,
Pulverized coal ratio (kg / t · pig) to be supplied to the combustion burner
And the ratio of synthetic resin material (kg / t-pig)
Weight ratio to the groundwater ratio (kg / t · pig) [(pulverized coal ratio +
(Synthetic resin material ratio) / coke ratio] 1.0 or more
Scrap melting method carried out under the conditions, The pulverized coal, powdery or flaky synthetic resin material and oxygen
of When injecting, at least pulverized coal must be burner diameter
Inject from the center of the direction or near
Into the surrounding area to mix the two.
Pulverized coal and at least part of the synthetic resin material in the pre-combustion chamber
And burn the combustion gas from the burner tip opening.
Introduced into the furnace to dissolve the scrap with the sensible heat of the combustion gas
To produce hot metal,SaidCombustion gas significant in furnace
As fuel gas without secondary combustion
And a scrap melting method. 5. The scrap melting method according to claim 4, wherein a powdery or granular synthetic resin material is blown into the pre-combustion chamber from the burner radial center or its vicinity. 6. A pre-combustion chamber is provided inside the burner tip opening.
A shaft furnace equipped with a burned combustion burner at the tuyerefor
Inside the shaft furnaceScrap and coke as iron sources
And in the pre-combustion chamber of the combustion burnerPulverized coal ratio P
C (kg / t · pig) and synthetic resin material ratio SR (kg / t
・ Pig) and oxygen flow rate O ₂ (Nm ³ / T · pig)
[(PC + SR) / O ₂ Is 0.7 kg / Nm ³ And above
Under such conditionsInject pulverized coal and oxygen
Inject granular, strip-shaped or massive synthetic resin material
Or charge,Fuel ratio of 300kg / t-pig or more,
Pulverized coal ratio (kg / t · pig) to be supplied to the combustion burner
And the ratio of synthetic resin material (kg / t-pig)
Weight ratio to the groundwater ratio (kg / t · pig) [(pulverized coal ratio +
(Synthetic resin material ratio) / coke ratio] 1.0 or more
Scrap melting method carried out under the conditions, The pulverized coal, powdery or flaky synthetic resin material and oxygen
of When injecting oxygen, apply oxygen only to the burner radial center.
Or from the vicinity, and at least pulverized coal
From the surrounding area, and oxygen from the surrounding area.
Pre-combustion by mixing and mixing pulverized coal and oxygen
Rapid combustion of pulverized coal and at least part of synthetic resin material indoors
And the combustion gas is introduced into the furnace through the burner tip opening.
And melt the scrap with the sensible heat of the combustion gas to produce hot metal.
Build andSaidSignificant secondary combustion of combustion gases in the furnace
It is characterized by being recovered as fuel gas without causing
Scrap melting method. 7. The scrap melting method according to claim 6, wherein the powdery or granular synthetic resin material is blown into the pre-combustion chamber from around oxygen blown from the burner radial center or its vicinity. . 8. The blowing or charging of the synthetic resin material into the pre-combustion chamber is performed discontinuously or intermittently, and the blowing or charging of the synthetic resin material is performed simultaneously or temporarily with the blowing of pulverized coal. 8. The method according to claim 4, wherein the pulverized coal is blown in place of the pulverized coal.
2. The scrap dissolving method according to 1. 9. A hole in the pulverized coal blowing section a in the pre-combustion chamber.
The intersection point p between the shaft extension line and the hole axis extension line of the oxygen blowing part b is
Located at the end of the firing chamber or inside the burner Place
Using a combustion burner configured as described above.
Item 4. The scrap melting method according to Item 4, 5, 6, 7 or 8. 10. The combustion burner is blown into a pre-combustion chamber.
Almost all of the oxygen that has been removed is pulverized coal or pulverized
A charcoal characterized by being consumed for the combustion of charcoal and synthetic resin
The scrap melting according to claim 4, 5, 6, 7, 8, or 9
solution. 11. The amount of pulverized coal injected (weight) is a synthetic tree.
It must be at least 1/10 of the blowing amount (weight) of the fat material
Claims 1, 2, 3, 4, 5, 6, 7, 8, 9
Or the scrap dissolution method according to 10. 12. The amount of pulverized coal injected (weight) is
The feature is that it is more than the blowing amount (weight) of vinyl material
The scrap dissolving method according to claim 11, wherein 13. A method for controlling the inside of a combustion burner or a combustion burner.
The purity of oxygen blown into the combustion chamber is 95% or more
Claims 1, 2, 3, 4, 5, 6, 7,
Scrap melting according to 8, 9, 10, 11 or 12
Law.