WO2006080563A1 - Method for operating blast furnace - Google Patents

Abstract

Provided is a method for operating a blast furnace which can improve the combustibility in the mixed combustion of a solid reducing agent and a gaseous reducing agent and can be applied also to a practical furnace by the well-defined determination of the appropriate range of the injection rate of the solid reducing agent and the gaseous reducing agent. A method for operating a blast furnace involving injecting a gaseous reducing agent as an auxiliary reducing agent and a solid reducing agent from a tuyere, which comprises injecting the gaseous reducing agent at a controlled injection rate of 10 to 80 kg/t-p and the solid reducing agent at a controlled injection rate of 50 to 150 kg/t-p.

Description

 Blast furnace operation method Technical field

 The present invention is a gas reducing material mainly composed of pulverized coal, plastics, methane such as natural gas, etc. from blast furnace tuyere (tuyere). ) Blast furnace operation method. Background art

 Coke used as a reducing material in a blast furnace that produces pig iron requires expensive coking coal as a raw material, and its production equipment is a coke oven. ) Is generally expensive because it requires construction, operation, and repair costs. For this reason, it is desired to reduce pig iron production costs by reducing the amount of coatas used in the blast furnace.

 In order to achieve the above objectives, a large amount of pulverized coal, which is less expensive than Cotas, is used, and synthetic resin materials contained in waste materials are used as reducing materials for blast furnaces.

 However, solid reducing agents such as pulverized coal and synthetic resin materials (hereinafter referred to as solid reducing agents) are generally slow in burning velocity, unburnt char, etc. There is a problem that unburnt content of ash is generated and accumulates in the blast furnace as powder, impeding the stable operation of the blast furnace.

 Therefore, a means has been proposed for simultaneously injecting a gas reducing material having a fast ignition and combustion and promoting the combustion of the solid reducing material.

For example, Japanese Patent Publication No. 1- 2 9 8 4 7 discloses that the temperature of hot air supplied from a blow pipe is adjusted to 8 10 ° C or higher, and pulverized fuel (in recent years, Coal and coke put into the blast furnace play a role as a reducing agent for iron ore, so they are called “reducing material” from “fuel”, so they are called solid reducing material. Gas fuel parallel to the pipe (hereinafter referred to as “gas reducing material” for the reasons described above.) Blowing pipe is provided, and solid combustion and gas reducing material co-firing A technique for improving the combustibility of a solid reducing material by blowing into a blast furnace while performing (mixed combustion) is disclosed.

 In Japanese Patent Publication No. 1 1 2 9 8 4 7, the combustion heat of the gas reducing material is used to accelerate the temperature rise of the solid reducing material to cause quick combustion of the solid reducing material (quick combustion). However, the ratio of the solid reducing material to the gas reducing material (blow-off ratio) The injection ratio indicates the amount of reducing material injected per ton of pig iron, and the unit is expressed in kg / t-p.) Information on (injection rate) must be unclear. It is not possible to know whether the combustibility is improved in the case of the injection ratio.

 Therefore, the inventors have conducted various experiments on the technology disclosed in Japanese Patent Publication No. 1 _ 29 98 47 from the viewpoint of improving combustibility regardless of the injection ratio of the solid reducing material and the gaseous reducing material. It verified by. As a result, it is necessary to transfer the combustion heat of the gas reducing material to the solid reducing material in order to improve the combustibility regardless of the blowing ratio of the solid reducing material and the gas reducing material. It was found that the contact between the solid reducing material and the solid reducing material is important.

 In order to ensure this contact, a concentric lance (as shown in the example of Japanese Patent Publication No. 1 2 9 8 4 7) (gas reduction is performed on the outer periphery of the solid reducing material blowing pipe. Inject the gas reducing pipe with a lance that is structured so that the combustion flame of the gas reducing material wraps around the streamline of the solid reducing material, or from separate lances, respectively. When reducing material was injected, it became clear that it was necessary to adjust the position and direction of the lance very carefully so that the solid flow and gas flow from each lance were in good contact.

By the way, it is necessary to install the blow lance through a blast pipe of a blast furnace called a blow pipe. Therefore, it is desirable that the outer diameter is small, and that the larger the outer diameter of the blow lance is, Although it is necessary to open a large hole in the air duct, it will have a significant adverse effect on the strength and heat resistance of the air duct. Therefore, a concentric lance with an increased outer diameter can be used in an experimental furnace, but it is practically difficult to use in an actual manufacturing facility that is continuously operated for 24 hours.

 In addition, an experiment was conducted in which a solid reducing agent and a gaseous reducing agent were separately blown from a plurality of lances and the stream lines were brought into contact with each other, but it was still difficult. In other words, it is quite difficult to properly adjust the position and angle of the lance in the actual machine. Even if it can be adjusted properly, the flow velocity of the hot air, the protruding speed of the solid and gas reducing material

 (injection velocity) pulsates and the lance position changes due to fine vibrations of the manufacturing equipment, so it was difficult to keep the streamline in contact at all times. When the streamline is out of contact, the combustibility of the solid reductant decreases and a large amount of unburned matter is generated, resulting in poor permeability and blow-through phenomenon (channeling).

phenomenon) and other undesirable effects.

 Here, blow-through refers to a phenomenon in which the flow of reducing gas explosively resumes when the flow of reducing gas stops and the pressure in the furnace rises and reaches a certain pressure. In such a case, the charge in the furnace moves along with the resumption of the gas flow, which disturbs the distribution of the charge deposited in layers. If the distribution of the charge is disturbed, the air permeability will be further deteriorated and the reduction of iron oxide will be deteriorated.This will not only have a very bad influence on the operation of the blast furnace, but also the mechanical pressure on the blast furnace body due to the increase in pressure. There are also concerns about the thermal detrimental effects on various facilities due to damage and rapid hot gas ejection.

 As described above, Japanese Patent Publication No. 1 2 9 8 4 7 does not provide information on the injection ratio of the solid reducing material and the gas reducing material. It is unclear whether it is effective for improvement.

 In addition, a special lance as shown in Japanese Patent Publication No. 1 2 9 8 4 7 is required to improve the flammability regardless of the injection ratio of the solid reducing material and the gas reducing material. Implementation is difficult.

The present invention has been made to solve such problems of the prior art, and by clarifying the appropriate range of the blowing ratio of the gas reducing material and the solid reducing material, The purpose is to provide a blast furnace operation method that can be realized in actual equipment as well as improving combustibility in mixed firing of the base material and the gas reducing material. Disclosure of the invention

 The present invention has been made based on the elucidation of the combustion promotion mechanism of the solid reducing material by simultaneous injection of the above-described solid reducing material and gas reducing material, and various experiments based on the elucidation of the above-described problems. is there.

 (1) The blast furnace operating method according to the present invention is a blast furnace operating method in which a gas reducing material and a solid reducing material are blown from the tuyere as auxiliary reducing materials, and the blowing ratio of the gas reducing material is set to 10 to 80 kg / t_p. In addition, the solid reducing material is blown with the blowing ratio adjusted to 50 to 1 501 ^ g / tp.

The auxiliary reducing agent referred to here is a reducing material that is blown from the feather loca and is a general term for a gas reducing material and a solid reducing material. Gas reductant and solid is 兀 ^ ¹ J is usually Bt, at room temperature and atmospheric pressure), which is a gas and solid substance, respectively, and is blown as a reductant from the tuyere. The

 (2) Further, in the above (1), pulverized coal and / or a synthetic resin material is used as the solid reducing material.

 The pulverized coal mentioned here is coal powder blown from the tuyere, and the particle size is generally about 75 μπι or less. The synthetic resin material will be defined later.

 (3) Further, in the above (1) or (2), a gas reducing material containing 50 mass% or more of carbon is used in dry base elemental analysis. is there.

(4) Further, in the above (1) or (2), a gas reducing material containing CH ₄ as a main component is used. Brief Description of Drawings FIG. 1 is an explanatory diagram of a blast furnace and its peripheral equipment used for carrying out a blast furnace operating method according to an embodiment of the present invention.

Fig. 2 is an explanatory diagram of a combustion test apparatus used in an experiment for completing the present invention.

Fig. 3: A graph showing the measured results of gas injection ratio and flame temperature in an experiment to complete the present invention, showing the calculated value of thermal radiation energy and the combustion rate of pulverized coal (Part 1).

Fig. 4: A graph showing the actual measurement results of gas injection ratio and flame temperature in the experiment to complete the present invention, showing the calculated value of thermal radiation energy and the combustion rate of pulverized coal (Part 2).

Fig. 5: Graph showing the relationship between pulverized coal ratio and pulverized coal combustion rate.

FIG. 6 is a solid reducing material blowing device according to another embodiment of the present invention.

FIG. 7 shows a gas reducing material and solid reducing material blowing device according to another embodiment of the present invention.

 (Explanation of symbols)

 1 blast furnace, 2 blow pipe, 3 pulverized coal injection lance, 4 synthetic resin injection lance, 5 gas reducing material injection lance. BEST MODE FOR CARRYING OUT THE INVENTION

 The inventors examined the combustion by radiation heat that does not depend on the contact state of the streamline of the solid reducing material and the gas reducing material as means for promoting the combustion of the solid reducing material. The reason is that if the combustion mode uses radiant combustion that can promote combustion without depending on the contact state between the solid reducing agent and the gaseous reducing agent, contact combustion (combustion by conduction or convection heat), radiant combustion This is because it is possible to improve the flammability in general combustion regardless of the above.

 Details are as follows.

In general, the energy of thermal radiation from the black body face (the ideal surface that absorbs and radiates all electromagnetic energy) E is Stefan Bol In accordance with Tuman's law shell IJ (Stefan- Boltzmann law of radiation), with constant number σ and absolute temperature T,

Ε = σ · Τ ⁴ (W / m ² ) · · · · · (Expression 1)

Since we are now considering high temperature radiation from combustion products of gas reducing materials, the emissivity of air-fuel mixture such as CO ₂ , H ₂ 0 and N ₂ Where ε is ε, the available thermal radiation energy E * is

E * = E · σ · T ⁴ (W / m ² ) '· · · · (Expression 2)

 In this way, the energy of thermal radiation changes in proportion to the fourth power of the temperature, so the thermal radiation energy is very influenced by temperature.

 Therefore, it is understood that it is important to control the flame temperature of the gas reducing material in order to promote the combustion of the solid reducing material using the energy of heat radiation.

Also, the value of emissivity f varies with temperature, etc., and is approximately 0.06 for C0 ₂ and 0.05 for H ₂ 0. C0 ₂ is slightly larger. Therefore, Japanese Patent Publication No. 1-29847 states that hydrogen is the most advantageous gas reducing material because of its high hydrogen combustion rate, but considering the energy of thermal radiation, Reducing materials that produce C0 ₂ such as methane (CH ₄ ) are advantageous.

 As described above, it was found that it was important to control the flame temperature of the gas reducing material, so the combustion flame temperature of the gas reducing material in a hot blast stream was examined. In the following, methane gas was used as the gas reducing material.

In so-called preraixed combustion, in which oxygen and methane are ignited after sufficient mixing and combustion occurs, the combustion reaction force S is generated in an average, so the combustion temperature is the theoretical flame temperature (theoretical). flame temperature) (average temperature determined by enthalpy balance and mass balance) assuming an adiabatic system, calculated by calculation However, when methane is ejected from a lance into a hot air stream and burned, so-called diffusion combustion occurs, which is not necessarily equal to the theoretical flame temperature. The diffusion combustion here refers to the following. The gas reductant flow ejected from the lance has a conical shape with the lance at the apex. Since there is no oxygen inside the cone, the combustion reaction does not proceed, and the gas reducing material mixed with the hot air starts burning at the outer peripheral surface of the cone. After that, the flame diffuses and propagates toward the inside of the cone. This is called diffusion combustion.

 In this way, when methane is ejected from a lance into a hot air stream and burned, it becomes diffuse combustion, so the combustion temperature is not just an adiabatic mean temperature. Therefore, the flame temperature was determined by actual measurement. Specifically, it was as shown below.

 Combustion test equipment that can reproduce one tuyere of a real blast furnace as shown in Figure 2

The flame temperature was measured using a (combustion test furnace). The blast temperature is fixed at 120 ° C, the blast volume is 300 Nm ³ / hr, and the methane blowing ratio is 0 to 100 kg / tp (unit kg / tp is the gas per ton of pig iron. (Indicating the amount of blown in). The flame temperature was measured from the sideward observation window with a radiation thermometer at 10 Omm and 20 Omm downstream from the tip of the lance.

 The methane blowing ratio was converted from the blowing rate per hour to the blowing rate per ton of pig iron using the conversion formula shown in Equation 3.

 Gas. R = (V / Vb) XVg X (Mg / C). (Equation 3)

However,

 Gas. R: Methane injection ratio per ton of pig iron (k g -gas / t-p)

V: Basic unit of air flow (Amount of air required to produce 1 ton of pig iron) (Nm ^3-

Vb: Air flow per hour (Nm ³ _air / hr)

Vg: Methane injection volume per hour (Nm ³ -gas / hr)

Mg: Methane molecular weight (= 16) (kg -gas / kmol-gas) Figure 3 shows the result of measurement of - (gas / kmol- gas N m 3) flame temperature coefficient that converts the volume of methane moles ^{(= 22 4.): C} . The figure shows the calculated value of thermal radiation energy and the combustion rate of pulverized coal at the same time. The thermal radiant energy indicates the relative value (E * / E * 1200) when the thermal radiant energy (E * 1200) at 1 200 ° C is 1. The combustion rate of pulverized coal is measured by measuring the combustion rate after collecting the unburned dust by co-firing with the blown gas at the blow rate of 100 kg / tp after the measurement of the combustion temperature of the gas flame. . The measurement method of the burning rate was measured by the method described in the following reference.

 (Reference: Advanced pulverized coal injection technology and blast furnace operation: Edited by K. Ishii, ELSEVIER 2000, P. 68)

 As shown in Fig. 3, it was found that the flame temperature increased as the gas injection ratio increased, and became almost constant when the gas injection ratio was 18 kg / tp or more. Correspondingly, the thermal radiant energy from the flame increases as the gas injection ratio increases, but as shown in Equations 1 and 2, it increases in proportion to the fourth power of the temperature, so the slope is extremely small. It has become big. The combustibility of pulverized coal will be improved by receiving this heat radiation energy.

 The combustion rate of pulverized coal became almost constant when the gas injection ratio was 10 kg / tp or more. The combustion of pulverized coal is preceded by the combustion of volatile matter content, and then fixed carbon is combusted. Among them, the heat feeding rate controlling reaction is the volatile matter content. This is a release and its combustion reaction. When the gas injection ratio is 10 kg / tp or more, the thermal radiation energy continues to rise, but a sufficient amount of heat is supplied to burn the volatile matter of pulverized coal. Therefore, the combustion efficiency of pulverized coal is considered to be constant. In other words, in order to further increase the combustion rate of pulverized coal, it may be necessary to devise measures to increase the contact between fixed carbon and oxygen rather than supplying thermal radiation energy. In any case, in order to improve the combustibility of pulverized coal, the gas injection ratio is desirably 10 kg / t-p or more.

As the gas injection ratio was increased, the flame temperature began to drop at 75 kg / tp or higher as shown in Fig. 4. This is because, as mentioned above, combustion is a conical gas stream. The surface area does not increase as much as the blowing ratio is increased, while the room temperature gas is used as a coolant by increasing the gas blowing ratio. It is thought to work. Although the combustion rate is maintained even when the combustion temperature decreases, the combustion rate of pulverized coal begins to decrease at a gas injection ratio of 8 O kg Λ-p or more where the radiant energy E * / E * 1200 is less than 6. .

 Therefore, the blowing ratio of the gas reducing material can be in the appropriate range of 10 to 80 kg / t-p.

 Next, the upper and lower limits of the blowing ratio of the solid reducing material such as pulverized coal of the present invention will be examined. There is no particular restriction on the lower limit of the injection ratio of the solid reducing material, but if the pulverized coal injection rate is 50 kg / t-p or less, as shown in Fig. 5, The pulverized coal combustion rate was almost the same when the coal was injected alone and when the gas reducing agent and pulverized coal were injected simultaneously. Normally, pulverized coal is blown at room temperature or preheated depending on the case, but even when preheated, the temperature is below the pyrolysis temperature of coal (approximately 400 ° C) and hot air (approximately 1200 ° C). Compared to low temperature. Therefore, when the injection ratio of pulverized coal is large, the ambient temperature immediately after the injection is cooled by the pulverized coal and greatly decreases, so the combustion of the pulverized coal is significantly delayed. For this reason, by blowing the gas reducing material at the same time, the thermal radiation energy resulting from the combustion of the gas reducing material promotes the combustion of the pulverized coal. On the other hand, when the blowing ratio of pulverized coal is small, it can be seen that the ignited combustion of pulverized coal can be sufficiently induced only by supplying heat with hot air. In this way, if the pulverized coal injection ratio is 50 kg / tp or less, the pulverized coal can be easily burned sufficiently, so that a high combustion rate can be obtained without applying the present invention. Therefore, it is possible to operate economically while reducing expensive coatas.

On the other hand, the upper limit of the blowing ratio of the solid reducing material was found to be 150 kg / t-p from the results of actual machine tests in the examples described later. When a test for verifying the present invention was carried out with an actual machine, the blow-through phenomenon increased rapidly when the pulverized coal injection ratio exceeded 150 kg / tp. Although the combustion efficiency of pulverized coal was increased from 60 mass% to 70 mass% according to the present invention, It is estimated that 3 O mass% of the pulverized coal enters the furnace as unburned material and accumulates.

 In the above experiment, only pulverized coal was used as the blown solid reducing material, but similar results were obtained even when pulverized coal and synthetic resin were mixed and blown. In addition, atomized synthetic resin, atomized wood chips, or a mixture thereof may be used.

Synthetic resins used in the present invention are polypropylene, polyethylene, polystyrene, polyethylene terephthalate, vinyl chloride resin, _N- vinyl chloride resin, and poly (vinyl alcohol). ), Plastics mainly composed of C, H and O such as Celluloid (trademark), and it is particularly preferable to use used plastics from the viewpoint of promoting recycling of waste.

Used plastics are plastic products that are discharged as garbage from ordinary households, and scraps and defective products (industrial waste) generated during the manufacturing and processing of plastics at factories, etc. Foreign materials other than plastic (metal, paper, etc.) , Other inorganic substances and organic substances) are included. Specific examples of such used plastics (waste plastics) include plastic bottles, plastic bags, plastics packaging materials, pufstech film aplastics film, and plastic trays. tray), plastic cut cup 7 (plastics cup), magnetic card (magnetic card), magnetic tape, magnetic tape), IC card (flexible container), flexible board, printed board, Printed sheet, printed sheet, wire covering material, business equipment or home appliance (body and frame for home electric appliances), coated plywood board ), Pipe, pipe), hose, synthetic fiber) and clothing, clothing material), 7 fstech Palletized plastic molding compound, urethane: packing sheet, packing band, packing buffer material, electrical component (electric) part) toy, stationery product, toner, autoraative parts (eg tf ~ f, interior equipment, nounno

(bumper)), shredder dust for automobiles and home appliances, ion-exchange resin, artificial paper, synthetic-resin adhesive, synthetic Resin paint (synthetic-resin paint), recycled plastic fuel (waste plastic volume reduction), etc. are exemplified, and these are treated as waste or given treatment as required. Can be used. A mixture of these used plastics and product plastics may also be used.

In the above experiment, methane gas was used as the gas reducing material, but liquefied natural gas (LNG), city gas, liquefied petroleum gas (LPG), coatas gas (COG) ) Similar results were obtained with hydrogen gas injection. However, considering the thermal radiation from C 0 ₂ with a high emissivity shown in Equation 2 above, methane containing 50 mass% or more of carbon, liquefied natural gas, city gas, A reducing material containing carbon such as liquefied petroleum gas and coatus gas is more preferable. These gases are also easily available industrially. Hydrogen gas is disadvantageous compared to CO ₂ in terms of heat radiation, and pure hydrogen gas is difficult to obtain industrially.

 In particular, liquefied natural gas and city gas are desirable as readily available gases, and these are often mainly composed of methane (approximately 80% by volume or more of methane). Example

 Fig. 1 is an explanatory diagram of the outline of the blast furnace and its peripheral equipment used in the implementation of the blast furnace operating method according to this embodiment.

As shown in Fig. 1, the blast furnace used in the present embodiment and its peripheral equipment penetrated the blast pipe 2 of the blast furnace 1 having an internal volume of 3 2 2 3 m ³ and pulverized coal injection lance 3, A resin material blowing lance 4 and a gas reducing material blowing lance 5 are installed. Table 1 shows the analytical values of pulverized coal, synthetic resin material, and gas reducing material used in the present embodiment. In addition, Table 2 shows the constituent molecular analysis values of the gas reducing materials used. -In the examples described below, a blast furnace operation method in which a gas reducing material and a solid reducing material are injected as auxiliary reducing materials from the tuyere under various blowing conditions, and the blowing ratio of the gas reducing materials is set. Examples are shown in Tables 3 and 4 as examples in the range of 10 to 80 kg / t-p and the blowing ratio of the solid reducing material in the range of 50 to 150 kg / t-p. Indicated. Tables 5 and 6 show examples in which the blowing ratio of the gas reducing material and / or the blowing ratio of the solid reducing material was out of the range of the present invention as comparative examples.

 In order to operate the blast furnace stably, it is important to keep the theoretical adiabatic temperature at the tuyere constant at a value of about 200 ° C., so oxygen enrichment depends on each blowing condition. The rate (oxygen enrichment rate) was adjusted. At this time, the air flow rate was adjusted so that the amount of oxygen supplied to the blast furnace was 1 (ie, the production rate of pig iron was constant). In an embodiment with a high oxygen enrichment rate, the air flow is reduced.

 Here, regarding the replacement rate of pulverized coal, the coke ratio without reducing material blowing was 499 kg / t, and the replacement rate of gas reducing material and synthetic resin material was fixed at 1.0 for convenience. It was calculated by the following formula 4. Strictly speaking, the replacement rate varies depending on the type of reducing material, but it is extremely difficult to calculate the replacement rates of multiple types of reducing materials separately. For convenience, the replacement rate other than pulverized coal is fixed, and the replacement rate of multiple types of reducing materials is represented by the replacement rate of pulverized coal, but the goal is to ultimately reduce the total reducing material ratio In view of this, such a substitution rate calculation method is considered to be effective as a simple method.

(Formula 4) Example 1 shows the case where the gas reducing material C (methane) ratio is 20 kg / tp and the pulverized coal ratio is 70 kg / t-P. The substitution rate of pulverized coal is as high as 0.71, and it can be said that coke can be effectively reduced by the blowing reducing material.

Example 2 shows a case where the gas reducing material C ratio is 20 kg Λ- _Ρ , the pulverized coal ratio is 70 kg / tp, and the synthetic resin material ratio is 30 kg / tp. The blowing ratio of the solid reductant is 1 OO kg / t-p, which is within the scope of the present invention. Therefore, the substitution rate of pulverized coal is as high as 0.70. It can be said that.

 Example 3 shows a case where the gas reducing material C ratio is 40 kg / t-p and the pulverized coal ratio is 120 kg / t-p. The substitution rate of pulverized coal is as high as 0.71, and it can be said that the coke can be effectively reduced by the blowing reduction material.

 Example 4 shows a case where the gas reducing material C ratio is 60 kg / t-p, the pulverized coal ratio is 120 kg / t-p, and the synthetic resin material ratio is 20 kg / t-. As the blowing ratio of the solid reducing material is 140 kg / tp, which is within the scope of the present invention, the substitution rate of pulverized coal is as high as 0.70. I can say that.

 Example 5 shows a case where the gas reducing material A ratio is 20 kg / t-p and the pulverized coal ratio is 50 kg / t-p. The substitution rate of pulverized coal is as high as 0.72, and it can be said that coke can be effectively reduced by the blown reducing material.

 Example 6 shows the case where the gas reducing material A ratio is 20 kg / t-p, the pulverized coal ratio is 70 kg / t-p, and the synthetic resin material ratio is 30 kg / t_p. The injection ratio of the solid reducing material is 100 kg / t-p, which is within the scope of the present invention, so that the substitution rate of pulverized coal is as high as 0.73, and the blowing reduction material can effectively reduce the coke. I can say that.

 Example 7 shows a case where the gas reducing material A ratio is 40 kg / t_p and the pulverized coal ratio is 100 kg / t-p. The substitution rate of pulverized coal is as high as 0.73.

Example 8 shows the case of gas reducing material A ratio 60 kg / tp, the pulverized coal ratio 120 kg / tp and synthetic resin ratio was 20 kg / _t-P. The blowing ratio of the solid reducing material is 140 kg / t-p, which is within the scope of the present invention, so the substitution rate of pulverized coal is as high as 0.72, and the blowing reduction material can effectively reduce the coast. I can say that. Example 9 shows a case where the gas reducing material B ratio is 50 kg / tp, the pulverized coal ratio is 100 kg / tp, and the synthetic resin material ratio is 20 _kg / tp. The blowing ratio of the solid reducing material is 120 kg / tp, which is within the scope of the present invention, so the substitution rate of pulverized coal is as high as 0.74. I can say that.

Example 10 shows a case where the gas reducing material B ratio is 40 kg / t-p, the pulverized coal ratio is 70 kg / tp, and the synthetic resin material ratio is 40 kg / t- _P . The blowing ratio of the solid reducing material is 110 kg / tp, which is within the scope of the present invention, so the substitution rate of pulverized coal is as high as 0.73, and it can be said that coke can be effectively reduced by the blowing reducing material. .

 Example 11 shows a case where the gas reducing material A ratio is 10 kg / t-p and the pulverized coal ratio is 140 kg / t-p. The substitution rate of pulverized coal is as high as 0.72, and it can be said that the coatus can be effectively reduced by the blowing reduction material.

 Example 12 shows a case where the gas reducing material B ratio is 10 kg / t-p, the pulverized coal ratio is 100 kg / t-p, and the synthetic resin material ratio is 40 kg / t-p. The blowing ratio of the solid reducing material is 140 kg / t-p, which is within the scope of the present invention, so that the pulverized coal substitution rate is as high as 0.73, and the blowing reducing material can effectively reduce coke. I can say that.

 Example 13 shows a case where the gas reducing material C ratio is 10 kg / t-p and the pulverized coal ratio is 120 kg / t-p. The substitution rate of pulverized coal is as high as 0.73, and it can be said that coke can be effectively reduced by the blowing reduction material.

 Example 14: Gas reducing material A ratio 20kg / tp, gas reducing material B ratio 20kg / tp, gas reducing material C ratio 20kg / tp, pulverized coal ratio 50kg / tp and synthetic resin The case where the material ratio is 30 kg / t-p is shown. The blowing ratio of the gas reducing material is 60 kg / tp, and the blowing ratio of the solid reducing material is 80 kg / t_p, which is within the scope of the present invention, so the substitution rate of pulverized coal is as high as 0.72. It can be said that the coatus can be effectively reduced by the blowing reducing material.

On the other hand, Comparative Example 1 shows a case where the gas reducing material C ratio is 5 kg / tp and the pulverized coal ratio is 100 kg / tp. The ratio of the gas reducing material is small and out of the range of the present invention, and the substitution rate of pulverized coal is as low as 0.59. Comparative Example 2 shows the case where the gas reducing material C ratio is 30 kg / tp and the pulverized coal ratio is 160 kg / tp. The ratio of solid reductant is too large, which is outside the scope of the present invention, and the substitution rate of pulverized coal is as low as 0.53.

 Comparative Example 3 shows a case where the gas reducing material C ratio is 15 kg / t-p, the pulverized coal ratio is 120 kg / tp, and the synthetic resin material ratio is 40 kg / tp. The ratio of solid reductant is too large as 160 kg Λ-ρ in total, and it is out of the scope of the present invention, and the substitution rate of pulverized coal is as low as 0.52, and it can be said that coke is not effectively reduced by blowing reductant.

 Comparative Example 4 shows the case where the gas reducing material C ratio is 100 kg / t-p and the pulverized coal ratio is 100 kg / t-p. The ratio of gas reductant is too large, which is outside the scope of the present invention, and the substitution rate of pulverized coal is as low as 0.53.

 Comparative Example 5 shows a case where the gas reducing material A ratio is 5 kg / t-p and the pulverized coal ratio is 60 kg / t-p. The ratio of the gas reducing material is small and outside the scope of the present invention, and the substitution rate of pulverized coal is as low as 0.57, and it can be said that the coatus cannot be effectively reduced by the blowing reducing material.

 Comparative Example 6 shows the case where the gas reducing material A ratio is 30 kg / t_p and the pulverized coal ratio is 160 kg / tp. The ratio of solid reductant is too large, outside the scope of the present invention, and the substitution rate of pulverized coal is as low as 0.56, so it can be said that coke can not be effectively reduced by the blown reductant.

 Comparative Example 7 shows the case where the gas reducing material A ratio is 20 kg / t-p, the pulverized coal ratio is 120 kg / t-p, and the synthetic resin material ratio is 50 kg / t-p. The solid reducing agent ratio is 170 kg / t-p, which is outside the scope of the present invention, so the substitution rate of pulverized coal is as low as 0.53, and it can be said that coke is not effectively reduced by the blowing reducing agent.

 Comparative Example 8 shows the case where the gas reducing material A ratio is 100 kg / t-p and the pulverized coal ratio is 60 kg / t-p. Since the ratio of the gas reducing material is too large and out of the scope of the present invention, the substitution rate of pulverized coal is as low as 0.53, and it can be said that the coatus cannot be effectively reduced by the blowing reducing material.

Comparative Example 9 shows the case where the gas reducing material B ratio is 5 kg / t-p and the pulverized coal ratio is 50 kg / t_p. The ratio of gas reductant is small and out of the scope of the present invention, and the substitution rate of pulverized coal is as low as 0.56. It can be said that coke can not be effectively reduced by blowing reductant. Comparative Example 10 shows a case where the gas reducing material B ratio is 90 kg / tp, the pulverized coal ratio is 120 kg / tp, and the synthetic resin material ratio is 40 kg / tp. The ratio of gas reductant is 90kg / tp and the ratio of solid reductant is 160kg / tp, both of which are too large and outside the scope of the present invention, so the substitution rate of pulverized coal is as low as 0.53. Therefore, it can be said that coke is not effectively reduced.

 Comparative Example 11 shows a case where the gas reducing material C ratio is 85 kg / t-p, the pulverized coal ratio is 115 kg / t-p, and the synthetic resin material ratio is 40 kg / t-p. The gas reducing agent ratio is 85 kg / tp, and the solid reducing agent ratio is 155 kg / tp, both of which are too large and outside the scope of the present invention, so the substitution rate of pulverized coal is as low as 0.54. Therefore, it can be said that coke is not effectively reduced.

Comparative Example 12 shows a case where the gas reducing material C ratio is 5 kg / tp, the pulverized coal ratio is 140 kg / tp, and the synthetic resin material ratio is 20 kg / t-p. The ratio of solid reductant is too high at 160kg / tp, and the ratio of gas reductant is small and outside the scope of the present invention, so the substitution rate of pulverized coal is as low as 0.52, and coke is made effective by blowing reductant. It can be said that it has not been reduced. Comparative Example 13 shows a case where the gas reducing material B ratio is 10 kg / tp, the gas reducing material C ratio is 5 kg / tp, and the pulverized coal ratio is 160 kg / -p. Since the ratio of solid reductant is too high at 160 kg / t- _P , the substitution rate of pulverized coal is as low as 0.51.

 Comparative Example 14 shows a case where the gas reducing material A ratio is 40 kg / tp, the gas reducing material B ratio is 40 kg / tp, the gas reducing material C ratio is 10 kg / tp, and the pulverized coal ratio is 100 kg / -p. . The ratio of gas reductant is too high at 90kg / t-p, so the substitution rate of pulverized coal is as low as 0.52, and it can be said that coke can not be effectively reduced by blowing reductant.

 As described above, Examples 1 to 14 of the present invention all show a high value of pulverized coal replacement ratio of 0.7 or more, and coke can be effectively reduced by the blown reducing material. Moreover, the occurrence of a blow-through phenomenon never occurred.

On the other hand, in all of Comparative Examples 1 to 14, the substitution rate of pulverized coal is 0.6 or less, and the coatus cannot be effectively reduced by the blowing reducing material. In addition, the occurrence of the blow-through phenomenon occurred frequently at 11 or more times. There are various methods for injecting the auxiliary reducing material. For example, two or three types of pulverized coal, synthetic resin material, and gas reducing material are simultaneously injected by concentric multi-tube lances. (Refer to Fig. 6) and a method of mixing and blowing two or three types in a single tube (see Fig. 7). A plurality of methods are conceivable, and the present invention is not particularly limited.

 In this regard, in the prior art, it is necessary to promote heat transfer by bringing the gas reducing material and the blown solid reducing material into contact with each other, so special attention was required for the lance structure and arrangement.

 However, in the present invention, since the heat radiation generated by the combustion of the gas reducing material is used, there is no particular restriction on the structure of the lance and the blowing method, and the implementation on the actual machine is easy. Industrial applicability

In the present invention, in a blast furnace operating method in which a gas reducing material and a solid reducing material are blown from the tuyere as an auxiliary reducing material, the blowing ratio of the gas reducing material is set to 10 to 80 kg / t-p, and Since the blowing ratio of the solid reducing material was adjusted to 50 to 1500 kg / tp, it was blown. Therefore, all combinations and combinations of the blowing ratios of the solid reducing material and the gas reducing material were tested. Optimal blowing conditions can be determined without churning, reducing the cost of the production of pig iron and reducing the cost of pig iron production.

組成 vol%

Composition vol%

¾V body 兀 Gas 3S 兀 Gas reducing material A material B material C

(COG) (LPG) (CH ₄ )

H ₂ 58.4--

CO 6.4--

CH ₄ 27.3-100

C ₂ H ₄ 2.6-One

G ₂ H6 0.8--

C _{3 6} 0.3--

C3H ₈ - 82.3 -

C ₄ H ₁₀ - 17.7 -

C0 ₂ 1.9-One

N ₂ 2.3--

Claims

The scope of the claims 1. In a blast furnace operation method in which a gas reducing material and a solid reducing material are blown from the tuyere as an auxiliary reducing material, the blowing ratio of the gas reducing material is set to 10 to 80 kg / tp, and the blowing ratio of the solid reducing material is set to Blast furnace operation method of adjusting to 50 to 1 50 kg / tp. 2. The method for operating a blast furnace according to claim 1, wherein pulverized coal and / or synthetic resin material is used as the solid reducing material. 3. The method for operating a blast furnace according to claim 1 or 2, wherein a gas reducing material containing 5 Omass% or more of carbon is used in elemental analysis on a dry basis. 4. The method for operating a blast furnace according to claim 1 or 2, wherein a gas reducing material containing CH ₄ as a main component is used.