Hydrogen-rich gas spray gun for blast furnace

Abstract

The utility model discloses a hydrogen-rich gas spray gun for a blast furnace, which comprises a coal powder conveying metal inner pipe, a coal powder conveying metal outer pipe, a hydrogen-rich gas conveying metal outer pipe, a coal inlet and a coal outlet, the outer side of the inner pulverized coal conveying metal pipe is sleeved with the outer hydrogen-rich gas conveying metal pipe, an annular space for conveying hydrogen-rich gas is formed between the inner pulverized coal conveying metal pipe and the outer hydrogen-rich gas conveying metal pipe, and the same end of the annular space and the coal outlet serves as a gas outlet; the hydrogen-rich gas pipeline is communicated with the annular space, and a venturi flow control valve is mounted on the hydrogen-rich gas pipeline. A venturi flow control valve is arranged on a hydrogen-rich gas conveying metal outer pipe of the spray gun, the gas inlet amount and the gas inlet speed of a hydrogen-rich gas source are reliably reduced, and an online adjusting means is provided for remote debugging and operation and maintenance.

Description

Technical Field

[0001] The utility model belongs to the technical field of special equipment for blast furnace metallurgy, and in particular relates to a hydrogen-rich gas spray gun for a blast furnace. Background Art

[0002] The steel industry is a key industry for carbon reduction efforts. In the entire steel production process, about 70% of carbon emissions come from the blast furnace process, and this process will remain the mainstream ironmaking link now and in the future. Therefore, it is particularly important to optimize the consumption of carbon-containing materials in the blast furnace process.

[0003] The blast furnace hydrogen-rich injection smelting technology mainly uses hydrogen-rich gases such as natural gas, coke oven gas, and hydrogen to partially replace solid fuels such as coal powder or coke used for blast furnace tuyere combustion. In addition, the hydrogen element carried in the hydrogen-rich gas fuel can participate in the reduction reaction under high temperature conditions to generate metallic iron, and the product is water vapor, thereby achieving the goal of reducing carbon consumption per ton of iron.

[0004] Traditional hydrogen-rich gas injection lances primarily come in straight-tube and sleeve-tube styles. Given the unique characteristics of hydrogen-rich gas, the mainstream market choice is straight-tube lances. These lances are placed on either side of the tuyere, with one side injecting pulverized coal and the other injecting hydrogen-rich gas. However, single-lance injection produces large volumes of hydrogen-rich gas at high velocities, leading to uneven delivery to the furnace, impacting smooth flow and hydrogen utilization. Unused hydrogen can also escape into the top gas, posing a safety hazard. Taking a 2500 blast furnace as an example, it has 30 tuyeres. Affected by the blast furnace's injection conditions, the furnace pressure in the tuyere area is 4 kg, and the pressure at the injection end is no less than 5 kg. As a result, only 4 to 6 tuyere hydrogen-rich lances are needed to reach the upper limit of furnace conditions. The flow rate of the hydrogen-rich gas in the lance varies greatly depending on the medium: natural gas injection process flow rates are approximately 90 m / s, coke oven gas approximately 120 m / s, and pure hydrogen approximately 500 m / s. This leads to uneven initial distribution of gas flow in the tuyere area, affecting smooth flow and limiting the carbon reduction capacity per ton of iron. Especially when pure hydrogen is injected, the flow rate is far higher than the safe value, and most of it does not participate in the reduction in the furnace and directly escapes into the top gas, resulting in poor overall carbon reduction capacity.

[0005] The inner tube of a sleeve-type lance injects a pulverized coal mixture, while the outer tube injects cooling air to extend its operating life. Some scholars and experts have proposed directly replacing the cooling gas in the sleeve-type lance with hydrogen-rich gas to achieve the purpose of injecting hydrogen-rich gas into the furnace. However, hydrogen is a flammable, explosive, and highly dangerous gas, and direct replacement poses extremely high safety risks. Hydrogen also easily corrodes steel pipes under high temperature conditions, shortening the sleeve-type lance's service life and posing a significant safety hazard. However, the sleeve-type lance has the advantage of a smaller air intake per lance, which can achieve uniform injection around the circumference of the blast furnace.

[0006] Therefore, it is necessary to make improvements to the sleeve-type spray gun to overcome the above problems. Utility Model Content

[0007] The utility model is a key technology innovation of hydrogen metallurgy in the iron and steel metallurgical industry and a technology for developing special blast furnace injection equipment. The flow rate of hydrogen-rich gas is controlled by a Venturi flow control valve, so that the blast furnace can be more smooth and efficient after hydrogen-rich injection. The carbon reduction effect per ton of iron of the blast furnace hydrogen-rich injection technology can be further improved. It is conservatively estimated that the comprehensive carbon reduction will be increased to 9-10%. It has strong universality and certain promotion value.

[0008] To solve the above problems, the present application provides a hydrogen-rich gas lance for a blast furnace, comprising:

[0009] A metal inner pipe for conveying pulverized coal, wherein the inner pipe is used to convey pulverized coal. The end of the pipe section of the metal inner pipe for conveying pulverized coal extending from the outer metal pipe for conveying hydrogen-rich gas serves as a coal inlet, and the other end of the metal inner pipe for conveying pulverized coal serves as a coal outlet.

[0010] The outer metal tube for conveying hydrogen-rich gas is sleeved on the outer side of the inner metal tube for conveying pulverized coal, forming an annular space between the inner metal tube for conveying pulverized coal and the outer metal tube for conveying hydrogen-rich gas. The annular space is used for conveying hydrogen-rich gas, and the same end of the annular space and the coal outlet serves as a gas outlet.

[0011] A hydrogen-rich gas pipeline is in communication with the annular space and is used for delivering hydrogen-rich gas to the annular space. A venturi flow control valve is installed on the hydrogen-rich gas pipeline.

[0012] Optionally, a purge gas pipeline is further included, and the purge gas pipeline is connected to the pipe section where the coal powder conveying metal inner pipe extends out of the hydrogen-rich gas conveying metal outer pipe.

[0013] Optionally, a grounding wire connector is provided on the tube wall of the hydrogen-rich gas conveying metal outer tube.

[0014] Optionally, a ceramic lining is provided on the inner surface of the hydrogen-rich gas conveying metal outer tube.

[0015] Optionally, a coal injection hose connector is fixedly connected to the coal inlet, and the coal injection hose connector is used to be connected to the coal injection hose.

[0016] Optionally, the purge gas pipeline is arranged to be inclined toward the coal inlet; and the hydrogen-rich gas pipeline is arranged to be inclined toward the coal inlet.

[0017] Compared with the prior art, this application has the following beneficial effects:

[0018] (1) The hydrogen-rich gas is injected through the annular space, which greatly reduces the gas output and gas output speed of a single spray gun under working conditions, making the initial distribution of blast furnace gas more reasonable. The cross-section of the annular space of the pure hydrogen spray gun is approximately 1 / 2 to 1 / 6 of the cross-section of the natural gas / coke oven gas spray gun. The speed of the hydrogen-rich gas entering the tuyere under working conditions can be reliably controlled, reducing central escape and improving utilization;

[0019] (2) Before the hydrogen-rich gas enters the annular space, a Venturi flow control valve is set to reliably reduce the intake volume and intake speed of the hydrogen-rich gas source, and provide an online adjustment method for remote debugging and operation and maintenance;

[0020] (3) A grounding wire connector is provided on the wall of the metal outer tube for connecting to the grounding wire to improve system safety.

[0021] (4) The inner surface of the outer tube of the spray gun head is lined with ceramic, which can prevent high-temperature surge and reduce hydrogen corrosion.

[0022] (5) A purge gas pipeline is connected to the pulverized coal conveying metal inner tube. After the pulverized coal injection stops, the purge gas is blown out to the air outlet through the pulverized coal conveying metal inner tube, which can keep the pulverized coal conveying metal inner tube in a positive pressure state and prevent the high-temperature coal gas from flowing back. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a schematic diagram of a hydrogen-rich gas lance for a blast furnace according to an embodiment of the present invention.

[0024] Reference numerals:

[0025] Coal injection hose connector 1, coal powder conveying metal inner tube 2, hydrogen-rich gas conveying metal outer tube 3, spray gun head 5, purge gas pipeline 6, hydrogen-rich gas pipeline 7, Venturi flow control valve 8, grounding wire connector 9. DETAILED DESCRIPTION

[0026] The following is a clear and complete description of the technical solution of the present invention in conjunction with the accompanying drawings. Obviously, the embodiments described are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0027] In the description of the embodiments of the present application, it should be noted that, unless otherwise clearly stipulated and limited, the terms "installation" and "connection" should be understood in a broad sense. For example, "connection" can be a detachable connection or a non-detachable connection; it can be a direct connection or an indirect connection through an intermediate medium. Among them, "fixed connection" means that the two are connected to each other and the relative position relationship after the connection remains unchanged. "Rotational connection" means that the two are connected to each other and can rotate relative to each other after the connection. The directional terms mentioned in the embodiments of the present application, such as "inside" and "outside", etc., are only reference to the directions of the accompanying drawings. Therefore, the directional terms used are for better and clearer explanation and understanding of the embodiments of the present application, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the embodiments of the present application.

[0028] The hydrogen-rich gas spray gun for a blast furnace of the present application is used to spray coal powder and hydrogen-rich gas into the furnace at the blast furnace tuyere, and includes a coal injection hose connector 1, a metal inner tube 2 for conveying coal powder, a metal outer tube 3 for conveying hydrogen-rich gas, a purge gas pipeline 6, a hydrogen-rich gas pipeline 7, a Venturi flow control valve 8, and a grounding wire connector 9.

[0029] The pulverized coal conveying metal inner tube 2 is disposed inside the hydrogen-rich gas conveying metal outer tube 3 and is used to convey pulverized coal within the pulverized coal conveying metal inner tube 2. An annular space is formed between the pulverized coal conveying metal inner tube 2 and the hydrogen-rich gas conveying metal outer tube 3, and hydrogen-rich gas is conveyed within the annular space.

[0030] One end of the pulverized coal conveying metal inner tube 2 extends from the hydrogen-rich gas conveying metal outer tube 3, and the end extending from the hydrogen-rich gas conveying metal outer tube 3 serves as a coal inlet. The coal inlet is fixedly connected to a coal injection hose connector 1 for connecting to the coal injection hose. The pulverized coal conveyed from the coal injection hose connector 1 can enter the pulverized coal conveying metal inner tube 2, flow along the pulverized coal conveying metal inner tube 2 to the other end of the pulverized coal conveying metal inner tube 2, and be ejected from the other end of the pulverized coal conveying metal inner tube 2. The other end of the pulverized coal conveying metal inner tube 2 serves as a coal outlet. The outlet of the annular space at this end serves as an air outlet. The coal outlet of the pulverized coal conveying metal inner tube 2 is flush with the air outlet of the hydrogen-rich gas conveying metal outer tube 3.

[0031] In addition, combustion will occur when pulverized coal and hydrogen-rich gas enter the furnace, and the high-temperature coal gas after combustion may flow back from the lance. Therefore, a purge gas pipeline 6 can be connected to the pipe section where the pulverized coal conveying metal inner tube 2 extends from the hydrogen-rich gas conveying metal outer tube 3. After the pulverized coal injection stops, purge gas is introduced into the pulverized coal conveying metal inner tube 2 through this pipeline. The purge gas is blown out of the blast furnace tuyere through the pulverized coal conveying metal inner tube 2 to maintain a positive pressure in the pulverized coal conveying metal inner tube 2 and prevent the high-temperature coal gas from flowing back. The purge gas can be air.

[0032] A hydrogen-rich gas pipeline 7 is connected to the outside of the hydrogen-rich gas delivery metal outer tube 3. One end of the hydrogen-rich gas pipeline 7 is connected to the annular space, and the other end is connected to an external hydrogen-rich gas source, so as to transport hydrogen-rich gas into the annular space. The hydrogen-rich gas flows from the annular space to the gas outlet.

[0033] A Venturi flow control valve 8 is installed on the hydrogen-rich gas pipeline 7. The Venturi flow control valve 8 consists of three parts: a "contraction section," a "throat," and a "diffusion section." It uses a flow measurement method based on the Bernoulli equation and the flow continuity equation. The Venturi flow control valve 8 consists of a circular measuring tube and a core body inserted into and coaxial with the measuring tube. The radial outer surface of the core body has a geometric profile similar to that of the inner surface of the Venturi tube, and forms a different-diameter annular flow gap with the inner surface of the measuring tube. This structure can reduce the erosion and accumulation of sharp edges by high-speed gas, facilitate the purging of residual hydrogen-rich gas and reduce escape, and effectively adjust (rectify) the velocity distribution gradient of the fluid in the tube before throttling and any non-axisymmetric velocity distribution, thereby achieving high-precision and high-stability flow measurement. In addition, the Venturi flow control valve 8 can also be remotely controlled in real time as needed. The hydrogen-rich gas enters the annular space for annular gas output and cooperates with the Venturi flow control valve 8 to achieve remote online precise control of the hydrogen-rich gas flow, making the hydrogen-rich gas more uniform and stable in the circumferential direction of the blast furnace, maximizing the hydrogen utilization efficiency and increasing the solid carbon raw material substitution rate.

[0034] In some embodiments, the operating temperature at the end of the blast furnace tuyere lance can reach over 2000°C. Under such operating conditions, ordinary steel pipes can easily soften and surge, causing the flow trajectory of the injected material to abrade the tuyere device. Therefore, the inner surface of the hydrogen-rich gas conveying metal outer pipe 3 can be lined with a ceramic lining to prevent high-temperature surge and reduce hydrogen corrosion. In particular, the ceramic lining can be provided only in the lance head area.

[0035] In some embodiments, considering that the molecular mass of hydrogen-rich gas is smaller and its flow rate is higher than that of traditional blowing gas (nitrogen, compressed air) under the same pressure difference, it is inevitable that high-speed flow will generate static electricity with the steel pipe wall, and hydrogen may explode under the action of static electricity. Therefore, a grounding wire connector 9 is installed on the pipe wall of the hydrogen-rich gas conveying metal outer pipe 3 for connecting to the grounding wire to further improve the safety of the system.

[0036] In some embodiments, the purge gas pipeline 6 and the hydrogen-rich gas pipeline 7 are both arranged at an angle, for example, they may be inclined toward the coal inlet, so that the purge gas enters the pulverized coal conveying metal inner tube 2 in a substantially identical direction to the pulverized coal conveying direction. Similarly, the hydrogen-rich gas enters the annular space in a substantially identical direction to the conveying direction.

[0037] In some embodiments, the lance head 5 can be bent. The bending is conducive to the coal outlet and the gas outlet being closer to the hot surface, so that lower-priced coal can be sprayed.

[0038] Of course, the present invention may have many other embodiments. Without departing from the spirit and essence of the present invention, those skilled in the art may make various corresponding changes and deformations based on the present invention, but these corresponding changes and deformations shall fall within the scope of protection of the claims of the present invention.

Claims

1. A hydrogen-rich gas lance for a blast furnace, characterized in that: include: A metal inner pipe for conveying pulverized coal, wherein the inner pipe is used to convey pulverized coal. The end of the pipe section of the metal inner pipe for conveying pulverized coal extending from the outer metal pipe for conveying hydrogen-rich gas serves as a coal inlet, and the other end of the metal inner pipe for conveying pulverized coal serves as a coal outlet. The outer metal tube for conveying hydrogen-rich gas is sleeved on the outer side of the inner metal tube for conveying pulverized coal, forming an annular space between the inner metal tube for conveying pulverized coal and the outer metal tube for conveying hydrogen-rich gas. The annular space is used for conveying hydrogen-rich gas, and the same end of the annular space and the coal outlet serves as a gas outlet. A hydrogen-rich gas pipeline is in communication with the annular space and is used for delivering hydrogen-rich gas to the annular space. A venturi flow control valve is installed on the hydrogen-rich gas pipeline.

2. The hydrogen-rich gas lance for a blast furnace according to claim 1, characterized in that: It also includes a purge gas pipeline, which is connected to the pipe section where the coal powder conveying metal inner pipe extends out of the hydrogen-rich gas conveying metal outer pipe.

3. The hydrogen-rich gas lance for a blast furnace according to claim 1, characterized in that: A grounding wire connector is provided on the pipe wall of the hydrogen-rich gas conveying metal outer pipe.

4. The hydrogen-rich gas lance for a blast furnace according to claim 1, characterized in that: A ceramic lining is provided on the inner surface of the hydrogen-rich gas conveying metal outer tube.

5. The hydrogen-rich gas lance for a blast furnace according to claim 1, characterized in that: A coal injection hose connector is fixedly connected to the coal inlet, and the coal injection hose connector is used to be connected to the coal injection hose.

6. The hydrogen-rich gas lance for a blast furnace according to claim 2, characterized in that: The purge gas pipeline is arranged obliquely toward the coal inlet; the hydrogen-rich gas pipeline is arranged obliquely toward the coal inlet.

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