A method for injecting reducing gas into blast furnace

Abstract

The present invention discloses a blast furnace reducing gas injection method, which belongs to the technical field of blast furnace ironmaking, and solves the technical problem that the existing blast furnace gas injection method has the blast furnace edge development effect and causes the iron-containing charge to be unable to fully contact with the gas. The injection method is based on a blast furnace reducing gas injection device, the injection device includes a gas supply structure and a gas distribution structure, the gas supply is arranged in the furnace body, and the gas supply structure is connected to a gas source; the gas distribution structure is cylindrical, the top of the gas distribution structure is closed, the bottom of the gas distribution structure is provided with a gas outlet, the side wall of the gas distribution structure is provided with a through hole connected to the gas supply structure, and the gas distribution structure is located in the middle of the furnace body; the injection method includes the following steps: heating the temperature of the reducing gas to the target temperature; introducing the reducing gas into the blast furnace with a target injection amount through the injection device. The application has a high utilization rate of the reducing gas, a high efficiency of processing the iron-containing charge in the blast furnace, and at the same time increases the service life of the blast furnace.

Description

Technical Field

[0001] The invention belongs to the technical field of blast furnace ironmaking, and in particular relates to a blast furnace reducing gas injection method. Background Art

[0002] Blast furnace reducing gas injection technology is one of the effective measures to reduce costs and increase efficiency in blast furnace ironmaking. Blast furnace reducing gas injection can not only promote the development of indirect reduction in the furnace, reduce the consumption of coke and pulverized coal in the blast furnace, but also add a means of adjustment for blast furnace operation. Blast furnace operators can use blast furnace reducing gas injection to control the thermal state of the blast furnace and solve the problem of insufficient heat in the furnace body caused by high oxygen enrichment and full oxygen smelting in the blast furnace.

[0003] However, the existing method of injecting reducing gas into a blast furnace is mainly to set an air inlet at the lower part of the furnace body for injection. This method has the problems of small injection amount of reducing gas and easy development of reducing gas at the edge of the blast furnace, which shortens the residence time of the reducing gas injected into the furnace body, making it difficult to fully contact with the iron-containing charge, reducing the utilization rate of the gas, and the high-temperature airflow entering from the lower part of the furnace body is easy to scour the furnace wall, reducing the service life of the lower part of the blast furnace wall, further limiting the smelting effect of injecting reducing gas into the blast furnace. Summary of the invention

[0004] The present application aims to at least to some extent solve the technical problem that the existing blast furnace gas injection method has the blast furnace edge development effect and causes the iron-containing charge and the gas to be unable to fully contact. To this end, the present application provides a blast furnace reducing gas injection method.

[0005] The technical solution of this application is as follows:

[0006] A blast furnace reducing gas injection method, based on a blast furnace reducing gas injection device, the injection device comprises:

[0007] A gas supply structure is arranged in the middle of the furnace body, and the gas supply structure is connected to a gas source;

[0008] A gas distribution structure, the gas distribution structure is cylindrical, the top of the gas distribution structure is closed, the bottom of the gas distribution structure is provided with a gas outlet, the side wall of the gas distribution structure is provided with a through hole connected with the gas supply structure, and the gas distribution structure is located in the middle of the furnace body;

[0009] The method comprises the following steps:

[0010] Heating the reduction gas to a target temperature;

[0011] The reducing coal gas is introduced into the blast furnace at a target injection amount through the injection device, wherein the gas outlet of the injection device is toward the bottom of the blast furnace. After reducing the material in the lower part of the blast furnace, the reducing coal gas reduces the material in the middle and upper parts of the blast furnace and is finally discharged from the top of the blast furnace.

[0012] In some embodiments, the blowing method further comprises the steps of:

[0013] Recovering the gas discharged from the top of the blast furnace;

[0014] De-CO2 treatment of the recovered gas;

[0015] The de-CO2 treated coal gas is reheated and introduced into the blast furnace after heating.

[0016] In some embodiments, the target temperature is 700-900°C.

[0017] In some embodiments, the target injection volume is 100-600m 3 / tHM.

[0018] In some embodiments, the blast pressure value of the gas supply structure is 30-80 kPa less than the hot blast pressure value in the blast furnace.

[0019] In some embodiments, the air supply structure includes a main body, and the main body is processed with air supply holes along the length direction thereof, and the air supply holes are connected to the through holes.

[0020] In some embodiments, the bottom of the main body includes a first inclined surface and a second inclined surface opposite to each other, and an angle is formed between the first inclined surface and the second inclined surface.

[0021] In some embodiments, reinforcing ribs are provided between the air supply pipe and the main body, and the reinforcing ribs are provided along the length direction of the air supply pipe.

[0022] In some embodiments, two reinforcing ribs are disposed in the air supply structure, and the two reinforcing ribs are respectively located above and below the vent hole.

[0023] In some embodiments, the air supply structure includes an even number of main bodies, and the main bodies are arranged opposite to each other in pairs, and the reinforcing ribs of the two oppositely arranged main bodies are fixedly connected.

[0024] The embodiments of the present application have at least the following beneficial effects:

[0025] It can be seen from the above technical scheme that the blast furnace reducing gas injection method disclosed in the present application is based on the reducing gas injection device so that the output reducing gas will be output from the middle of the furnace body downward. On the one hand, the reducing gas will not directly flush the furnace wall, and the furnace wall is not easily damaged by the flushing of the reducing gas, thereby increasing the service life of the blast furnace; on the other hand, the movement path of the reducing gas is increased, the contact time between the reducing gas and the iron-containing charge is increased, and the problem of gas development at the edge of the blast furnace is not likely to occur. The reducing gas can be evenly distributed to various places in the furnace body, and the iron-containing charge in various places in the blast furnace can achieve effective contact with the reducing gas. The utilization rate of the reducing gas is high, and accordingly, the processing efficiency of the iron-containing charge in the blast furnace is high. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0027] Figure 1 A schematic flow chart showing a blast furnace reducing gas injection method in an embodiment of the present application is shown;

[0028] Figure 2 It shows a schematic structural diagram of a blast furnace reducing gas injection device in an embodiment of the present application;

[0029] Figure 3 Shows Figure 2 Schematic cross-sectional view along the AA direction;

[0030] Figure 4 Shows Figure 2 A schematic cross-sectional view along the BB axis;

[0031] Markings in the figure: 1-furnace body, 2-gas distribution structure, 3-main body, 4-gas valve, 5-reinforcement rib, 6-gas supply hole. DETAILED DESCRIPTION

[0032] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0033] In addition, the present application may repeat reference numbers and / or reference letters in different examples, and such repetition is for the purpose of simplicity and clarity, and does not in itself indicate the relationship between the various embodiments and / or settings discussed. In addition, the present application provides various specific examples of processes and materials, but those of ordinary skill in the art may recognize the application of other processes and / or the use of other materials.

[0034] Figure 1 A schematic flow chart showing a blast furnace reducing gas injection method in an embodiment of the present application is shown; Figure 2 It shows a schematic structural diagram of a blast furnace reducing gas injection device in an embodiment of the present application; Figure 3 Shows Figure 2 Schematic cross-sectional view along the AA direction; Figure 4 Shows Figure 2 Schematic cross-sectional view along the BB axis.

[0035] The present application is described below with reference to the accompanying drawings and specific embodiments:

[0036] like Figure 1 , Figure 2 , Figure 3 and Figure 4 As shown, this embodiment provides a blast furnace reducing gas injection device, which is arranged in the furnace body 1 of the blast furnace and is located in the middle of the furnace body 1, and is used for injecting reducing gas into the blast furnace to reduce the iron-containing charge in the furnace body 1. The injection device includes a gas supply structure and a gas distribution structure 2. The gas supply structure is arranged in the furnace body 1, and the gas distribution structure 2 is connected to the gas supply structure. The gas distribution structure 2 is cylindrical, the top end of the gas distribution structure 2 is closed, and the bottom end of the gas distribution structure 2 is provided with a gas supply port, and the side wall of the gas distribution structure 2 is provided with a through hole connected to the gas supply structure.

[0037] The gas supply structure is connected to a gas source, and the reducing gas will enter the gas distribution structure 2 through the gas supply structure and escape from the gas distribution hole into the furnace body 1, thus completing the supply of the reducing gas.

[0038] The spraying method comprises the following steps:

[0039] Step 100, heating the reducing gas to a target temperature.

[0040] The reducing gas can be produced and heated by a COREX furnace.

[0041] Step 200, introducing the reducing coal gas into the blast furnace with a target injection amount through the injection device, wherein the gas outlet of the injection device faces the bottom of the blast furnace, and the reducing coal gas reduces the materials in the lower part of the blast furnace, and then reduces the materials in the middle and upper parts of the blast furnace, and is finally discharged from the top of the blast furnace.

[0042] Reference Figure 2 and Figure 3 The blast furnace is placed vertically when in use, the cross section of the furnace body 1 is circular, the gas distribution structure 2 is located in the middle of the furnace body 1 and is arranged vertically. When the reducing gas overflows from the gas supply port, the reducing gas will first move downward and contact the iron-containing charge in the middle of the lower part of the furnace body 1. Since the gas supply port continuously supplies reducing gas into the furnace body 1, the reducing gas in contact with the iron-containing charge in the middle of the lower part of the furnace body 1 will gradually spread to the inner wall of the furnace body 1, and after contacting the bottom end of the inner ring wall of the furnace body 1, it will rise along the inner wall of the furnace body 1. Of course, part of the gas will also rise if it does not reach the inner wall of the furnace body 1, so it can be It is understood that the reducing gas output in the present embodiment will output the reducing gas downward from the middle of the furnace body 1. On the one hand, the reducing gas will not directly flush the furnace wall, and the furnace wall is not easily damaged by the flushing of the reducing gas, thereby increasing the service life of the blast furnace; on the other hand, the movement path of the reducing gas is increased, the contact time between the reducing gas and the iron-containing charge is increased, and the problem of gas development at the edge of the blast furnace is not likely to occur. The reducing gas can be evenly distributed to various places in the furnace body 1, and the iron-containing charge in various places in the blast furnace can achieve effective contact with the reducing gas. The utilization rate of the reducing gas is high, and accordingly, the processing efficiency of the iron-containing charge in the blast furnace is high.

[0043] At the same time, this embodiment can reduce the reduction burden of the area below the soft melting zone, reduce the amount of coke participating in the direct reduction reaction, and thus reduce the coke ratio of the blast furnace. The 700-900°C reducing gas injected from the furnace body 1 directly brings in a large amount of physical heat. The furnace body 1 area of ​​the blast furnace can reduce its dependence on the heat carried by the rising gas in the lower high-temperature zone of the blast furnace. Therefore, the amount of gas generated in the lower high-temperature zone of the blast furnace can be reduced, and large oxygen-enriched and full oxygen smelting operations can be implemented, which is conducive to increasing the output of the blast furnace. In addition, the gas supply structure can also support the iron-containing charge located above it, and reduce the load and extrusion borne by the charge located below the internal gas supply pipeline, reducing the blast furnace's requirements for coke strength, thereby reducing the production cost of coke.

[0044] Of course, a gas outlet is provided at the top of the blast furnace 1 to facilitate the recovery of the reducing gas. Therefore, the injection method in this embodiment also includes the steps of:

[0045] Step 300, recovering the gas exhausted from the top of the blast furnace.

[0046] Step 400, removing CO2 from the recovered gas.

[0047] Step 500, reheating the de-CO2 treated coal gas and introducing the heated coal gas into the blast furnace.

[0048] Through steps 300 to 500, the utilization rate of the reduction gas is improved and production materials are saved.

[0049] Further, see Figure 2 , the gas distribution structure 2 includes a circular tube and a first conical tube arranged above the circular tube, that is, the upper part of the gas distribution structure 2 is in the shape of a conical tube, and the through hole is arranged on the circular tube. After the reducing gas enters the inner cavity of the gas distribution structure 2, the inner wall shape of the first conical tube is conducive to guiding the reducing gas, so that the reducing gas has a horizontal component velocity when overflowing from the gas distribution port, thereby facilitating the dispersion of the reducing gas in the furnace body 1. A second conical tube is also arranged at the top of the first conical tube, and the taper of the second conical tube is greater than the taper of the first conical tube. It can be understood that by setting the second conical tube, the reducing gas entering the top of the gas distribution structure 2 is buffered to avoid the collision of the reducing gas with the top surface of the gas distribution structure 2, which causes the airflow of the reducing gas to be turbulent.

[0050] The air supply structure can be in the shape of a circular tube, or can refer to Figure 3 and Figure 4 The gas supply structure includes a main body 3, and the main body 3 is processed with a gas supply hole 6 along its length direction. The gas supply hole 6 is connected to the through hole. The two ends of the main body 3 are fixedly connected to the gas distribution structure 2 and the inner wall of the furnace body 1 respectively. The furnace body 1 is provided with an air inlet hole. The outlet pipe of the reduction gas generator inputs the reduction gas into the gas supply hole 6 through the air inlet hole. Of course, the gas valve 4 is provided on the outlet pipe. It is convenient for the operator to adjust the amount of reduction gas input into the furnace body 1. The main body 3 is cast with refractory materials to increase the service life.

[0051] Reference Figure 4 The bottom of the main body 3 includes a first inclined surface and a second inclined surface opposite to each other, and there is an angle between the first inclined surface and the second inclined surface. The two inclined surfaces have a guiding function, so that the rising reducing gas can rise along the first inclined surface and the second inclined surface, thereby reducing the high-temperature erosion of the reducing gas on the main body 3 and improving the service life of the main body 3. Furthermore, the top surface of the main body 3 is an arc surface, so that when the material is distributed into the furnace body, the material can fall smoothly.

[0052] A reinforcing rib 5 is provided between the air supply pipe and the main body 3, and the reinforcing rib 5 is provided along the length direction of the air supply pipe to improve the strength of the main body 3, reduce the deformation of the main body 3 during long-term use and cause air flow turbulence, and further improve the service life of the main body 3. Furthermore, two reinforcing ribs 5 are provided in the air supply structure, and the two reinforcing ribs 5 are respectively located above and below the vent hole to further improve the strength and resistance of the main body 3.

[0053] Taking into account that the gas distribution structure 2 is arranged in the furnace body 1 through the gas supply structure, the gas supply structure includes an even number of main bodies 3, and the main bodies 3 are arranged opposite to each other, that is, the axes of the gas supply holes 6 of the two oppositely arranged main bodies 3 are located on the same straight line, and the reinforcing ribs 5 of the two oppositely arranged main bodies 3 are fixedly connected. It can be understood that the same reinforcing rib 5 is used between the two oppositely arranged main bodies 3. The overall strength of the gas distribution structure 2 enables the gas distribution structure 2 to maintain a normal operating state for a long time, thereby enabling the blast furnace to maintain a good reduction effect and reduction efficiency of the iron-containing charge for a long time.

[0054] As a feasible implementation method, the diameter of the furnace body 1 parallel to the gas outlet is taken as the reference diameter, then the diameter of the gas outlet is 10-20% of the reference diameter, the height of the gas distribution structure 2 is 15-35% of the reference diameter, and at the same time, the outer ring wall of the main body 3 is coaxial with the gas supply pipe, and the equivalent diameter of the outer contour of the main body 3 is 5-10% of the diameter of the cross section at the furnace body 1 of the blast furnace where it is located, and the diameter of the gas supply hole 6 is 2-5% of the diameter of the cross section at the position of the blast furnace 1 where it is located, so that the main body 3 has a thicker wall thickness to improve resistance, thereby increasing the service life of the main body 3. At the same time, in this embodiment, the target temperature is 700-900℃, and the target injection volume is 100-600m 3 / tHM, the blast pressure of the gas supply structure is 30-80kPa less than the hot air pressure in the blast furnace. The operator selects the appropriate target temperature and target injection volume according to the characteristics of the iron-containing charge. For example, the target temperature can be 720℃, 750℃, 780℃, 800℃, 830℃ or 880℃, and the target injection volume can be 120m 3 / tHM, 170m 3 / tHM, 220m 3 / tHM, 270m 3 / tHM、320m 3 / tHM、370m 3 / tHM, 420m 3 / tHM or 520m 3 / tHM.

[0055] In the present application, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0056] In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise" and "counterclockwise" indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0057] It should be noted that all directional indications in the embodiments of the present application are only used to explain the relative position relationship, movement status, etc. between the components in a certain specific posture. If the specific posture changes, the directional indication will also change accordingly.

[0058] In this application, unless otherwise clearly specified and limited, the terms "connection", "fixation", etc. should be understood in a broad sense. For example, "fixation" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0059] In addition, the descriptions of "first", "second", etc. in this application are only for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of this application, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0060] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine different embodiments or examples described in this specification.

[0061] In addition, the technical solutions between the various embodiments can be combined with each other, but they must be based on the fact that they can be implemented by ordinary technicians in this field. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by this application.

[0062] Although the embodiments of the present application have been shown and described, those skilled in the art will appreciate that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present application, and that the scope of the present application is defined by the claims and their equivalents.

Claims

1. A blast furnace reducing gas injection method, characterized in that: Based on the blast furnace reducing gas injection device, the injection device comprises: A gas supply structure is arranged in the middle of the furnace body, the gas supply structure is connected to a gas source, the gas supply structure comprises a main body, the main body is processed with a gas supply hole along its length direction, the gas supply hole is connected with the through hole, the bottom of the main body comprises a first inclined surface and a second inclined surface opposite to each other, the first inclined surface and the second inclined surface have an included angle, a reinforcing rib is arranged between the gas supply pipe and the main body, and the reinforcing rib is arranged along the length direction of the gas supply pipe; A gas distribution structure, the gas distribution structure is cylindrical, the top of the gas distribution structure is closed, the bottom of the gas distribution structure is provided with a gas outlet, the side wall of the gas distribution structure is provided with a through hole connected to the gas supply structure, the gas distribution structure is located in the middle of the furnace body, wherein the gas distribution structure includes a round tube and a first conical tube arranged above the round tube, a second conical tube is further arranged at the top of the first conical tube, and the taper of the second conical tube is greater than the taper of the first conical tube; The spraying method comprises the following steps: Heating the reduction gas to a target temperature; The reducing coal gas is introduced into the blast furnace at a target injection amount through the injection device, wherein the gas outlet of the injection device is toward the bottom of the blast furnace. After reducing the material in the lower part of the blast furnace, the reducing coal gas reduces the material in the middle and upper parts of the blast furnace and is finally discharged from the top of the blast furnace.

2. The blast furnace reducing gas injection method according to claim 1, characterized in that: The spraying method further comprises the steps of: Recovering the gas discharged from the top of the blast furnace; De-CO2 treatment of the recovered gas; The de-CO2 treated coal gas is reheated and introduced into the blast furnace after heating.

3. The blast furnace reducing gas injection method according to claim 1, characterized in that: The target temperature is 700-900°C.

4. The blast furnace reducing gas injection method according to claim 1, characterized in that: The target injection volume is 100-600m 3 / tHM.

5. The blast furnace reducing gas injection method according to claim 1, characterized in that: The blast pressure value of the air supply structure is 30-80 kPa lower than the hot air pressure value in the blast furnace.

6. The blast furnace reducing gas injection device according to claim 1, characterized in that: Two reinforcing ribs are arranged in the air supply structure, and the two reinforcing ribs are respectively located above and below the air vent.

7. The blast furnace reducing gas injection device according to claim 1, characterized in that: The air supply structure comprises an even number of main bodies, wherein two of the main bodies are arranged opposite to each other, and the reinforcing ribs of the two oppositely arranged main bodies are fixedly connected.

Images