Blast furnace coal injection system additionally provided with air supply structure

Abstract

The utility model discloses a blast furnace coal injection system added with an air supply structure, which is provided with a pulverized coal bunker, two injection tanks are arranged below the pulverized coal bunker side by side, the middle of the top of each injection tank is provided with a pulverized coal blanking pipe connected with the bottom of the pulverized coal bunker, and the lower parts of the two injection tanks are respectively provided with an annular injection structure; a first nitrogen supply pipe is further arranged, and a first air blowing pipe, a second air blowing pipe and a third air blowing pipe are led out of the first nitrogen supply pipe at the same time. The side walls, close to the lower parts, of the two injection tanks are respectively connected with a discharge pipe, the two discharge pipes are simultaneously connected to a secondary air supply device, an air outlet of the secondary air supply device is connected with a concentrated pulverized coal pipe, the concentrated pulverized coal pipe is connected to a blast furnace distributor, and the blast furnace distributor conveys pulverized coal into a blast furnace; a tail end air supply device is arranged on the concentrated pulverized coal pipe at the input end of the blast furnace distributor; the application of the tail end air supply structure has an obvious promotion effect on the kinetic energy improvement of the coal flow of the blast furnace coal injection gun, and the phenomenon that the coal flow brushes the sleeve can be effectively reduced.

Description

Technical Field

[0001] This utility model relates to the field of pulverized coal injection and conveying technology, and in particular to a blast furnace pulverized coal injection system with an added gas replenishment structure. Background Technology

[0002] In blast furnace pulverized coal injection (PCO) processes, the main power medium for conveying pulverized coal is nitrogen or air, and the primary conveying method is pneumatic conveying. Pneumatic conveying is divided into dilute-phase pneumatic conveying and dense-phase pneumatic conveying. Dense-phase pneumatic conveying is widely used in blast furnace PCO processes due to its advantages such as low gas velocity, high solid-to-gas ratio, low energy consumption, low gas consumption, minimal pipeline wear, and high safety performance. However, research on the flow patterns within dense-phase pneumatic conveying pipes has been limited by the complexity of gas-solid two-phase fluid mechanics, materials, and equipment, as well as the limitations of existing experimental methods and conditions. For a long time, the understanding of its mechanisms and theories has not been fully mature, thus posing significant difficulties for engineering design and calculation. However, from the perspective of macroscopic fluid dynamics, pneumatic conveying technology essentially "fluidizes" the conveyed solid particles, forming a "pseudo-fluid" with characteristics similar to a viscous liquid. The flow patterns within the conveying pipeline are usually classified as vertical or horizontal: I. Vertical Pipelines. (1) Uniform flow: The solid phase is evenly distributed in the pipe. (2) Dense flow: The particles still move upward, but the distribution is no longer uniform, and the arrangement of density varies. (3) Bolted flow: The particles begin to get stuck in the movement, forming material plugs, and the movement becomes unstable. (4) Columnar flow: The solid particles aggregate, forming material columns, and the movement resistance increases significantly, even causing blockage. II. Horizontal pipe (1) Uniform flow: The solid phase is evenly distributed in the cross-section of the pipe, and the flow is smooth. (2) Dense flow: Gravity is evident, and the particle distribution is uneven, with the bottom particles jumping forward. (3) Dune flow: The particles begin to settle under the action of gravity, forming wavy dunes at the bottom of the pipe. (4) Bolted flow: The particles begin to get stuck in the movement, forming material plugs, and the movement becomes unstable.

[0003] When pulverized coal is transported over long distances, insufficient kinetic energy and a decrease in flow velocity may occur at the end, leading to blockage of the pulverized coal injection pipe and pulverized coal injection gun. This utility model aims to address this technical problem by proposing a new solution to compensate for the loss of pulverized coal flow velocity and improve the problem of blockage of the pulverized coal injection pipe and pulverized coal injection gun. Utility Model Content

[0004] The purpose of this invention is to address the above-mentioned issues by providing a blast furnace pulverized coal injection system with an added gas replenishment structure. This invention eliminates the root cause of pulverized coal injection pipe blockage from the aspects of process and structural control, and effectively reduces the phenomenon of coal flow brushing.

[0005] The specific solution of this utility model is as follows: a blast furnace pulverized coal injection system with an added gas replenishment structure, comprising a pulverized coal silo, two injection tanks arranged side by side below the pulverized coal silo, each injection tank having a pulverized coal feed pipe connected to the bottom of the pulverized coal silo at the top center of its respective top, and each injection tank having an annular injection structure at its lower part, the annular injection structure spraying towards the corresponding injection tank interior; a first nitrogen supply pipe is also provided, which simultaneously leads out to a first blowing pipe, a second blowing pipe, and a third blowing pipe, wherein the first blowing pipe simultaneously blows air to the top of both injection tanks, the second blowing pipe simultaneously blows air to the top of both injection tanks, and the third blowing pipe simultaneously blows air to the top of both injection tanks. A ring-shaped venting structure is used for ventilation, and a third venting pipe is connected to the bottom of two venting tanks. A discharge pipe is connected to the lower side wall of each of the two venting tanks, and the two discharge pipes are connected to a secondary venting device. A secondary venting pipe is also led out from the first nitrogen supply pipe and leads to the secondary venting device. The outlet of the secondary venting device is connected to a centralized pulverized coal pipe, which is connected to the blast furnace distributor. The blast furnace distributor delivers pulverized coal to the blast furnace. An end venting device is also installed on the centralized pulverized coal pipe at the input end of the blast furnace distributor. An end venting structure is connected to the side wall of the end venting device.

[0006] Furthermore, the end-gas replenishment structure described in this utility model includes a second nitrogen supply pipe, through which nitrogen is introduced and connected to the end-gas replenisher. The second nitrogen supply pipe is sequentially equipped with a manual ball valve, a check valve, a pneumatic regulating valve, a gas flow meter, and a pneumatic ball valve, with one side of the manual ball valve connected to the end-gas replenisher.

[0007] Furthermore, each of the injection tanks in this invention is provided with a pressure relief pipe on one side of its top, with the upper end of the pressure relief pipe connected upward to the pulverized coal silo; a solenoid valve is installed on the pressure relief pipe.

[0008] Furthermore, the annular spray structure described in this utility model includes an annular nozzle, which is installed on the outer wall of the lower part of the corresponding spray tank. Each annular nozzle is provided with a jet nozzle at even intervals, and the jet nozzle passes through the tank wall of the corresponding spray tank to spray nitrogen gas into it.

[0009] Furthermore, in this invention, a branch air supply pipe is provided between the second air supply pipe and the first air supply pipe on the outside of each blow-off can, and a solenoid valve is provided on the branch air supply pipe.

[0010] Furthermore, in this invention, the first air blowing pipe, the second air blowing pipe, and the third air blowing pipe are all equipped with solenoid valves.

[0011] Furthermore, the discharge pipe described in this utility model is equipped with a solenoid valve.

[0012] Furthermore, in this invention, the terminal gas supplementer is located at the right-angle bend of the centralized pulverized coal pipe at the input end of the blast furnace distributor.

[0013] This utility model has the following beneficial effects:

[0014] 1. The application of the end-gas replenishment structure has a significant promoting effect on the kinetic energy of the coal flow in the blast furnace pulverized coal injection gun. From the perspective of process control, it eliminates the root cause of blockage in the pulverized coal injection gun and related pulverized coal injection pipelines. In actual use, by fine-tuning the insertion angle of the pulverized coal injection gun, the phenomenon of coal flow brushing can be effectively reduced.

[0015] 2. The adjustment and precise control between the end-point gas supply structure and the secondary gas supply device provide a large adjustment range for the fully automatic and precise pulverized coal injection control of the blast furnace, ensuring uniform and accurate pulverized coal injection.

[0016] 3. The application of the end-point air supply structure significantly reduces the secondary air supply flow, reduces the consumption of injection power medium, increases the injection concentration, reduces the initial flow velocity of pulverized coal in the pipeline, and reduces wear on the pulverized coal pipeline.

[0017] 4. The end-point air supply structure has broad application prospects in pulverized coal injection systems with a conveying distance of more than 200m. It has the advantages of low engineering investment and simple process layout. It has a significant energy-saving effect on the consumption of pulverized coal conveying medium. For pulverized coal injection systems with a conveying distance of more than 400m, a multi-stage air supply system can be added to achieve better conveying effect. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the overall structure of this utility model.

[0019] In the diagram: 1—Pulverized coal bin, 2—Pressure relief pipe, 3—Pulverized coal feed pipe, 4—First air blowing pipe, 5—Branch air supply pipe, 6—Injection tank, 7—Solenoid valve, 8—Second air blowing pipe, 9—Third air blowing pipe, 10—Secondary air supply pipe, 11—Secondary air supply device, 12—Centralized pulverized coal pipe, 13—Pneumatic ball valve, 14—Gas flow meter, 15—Pneumatic regulating valve, 16—Check valve, 17—Manual ball valve, 18—End air supply device, 19—Blast furnace distributor, 20—Blast furnace, 21—Discharge pipe, 22—Annular nozzle, 23—Air jet nozzle, 24—First nitrogen supply pipe, 25—Second nitrogen supply pipe. Detailed Implementation

[0020] The technical solution of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model. In the description of this utility model, it should be noted that the terms "upper," "lower," "inner," "outer," etc., indicating orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the utility model product is in use. They are only for the convenience of describing this utility model or simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed or operated in a specific orientation, and therefore should not be construed as a limitation of this utility model.

[0021] In the description of this utility model, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," and "connect" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0022] See Figure 1This utility model is a blast furnace pulverized coal injection system with an added gas replenishment structure. It includes a pulverized coal silo 1, with two injection tanks 6 arranged side-by-side below the silo. Each injection tank has a pulverized coal feed pipe 3 at the top center, connecting to the bottom of the pulverized coal silo. Each injection tank has an annular injection structure at its lower part, which injects nitrogen into the corresponding injection tank. Furthermore, the annular injection structure includes an annular nozzle 22, which is mounted on the outer wall of the lower part of the corresponding injection tank. Each annular nozzle has evenly spaced air nozzles 23 that penetrate the tank wall to inject nitrogen into the tank. A first nitrogen supply pipe 24 is also provided, which simultaneously leads to a first blowing pipe 4 and a second blowing pipe 4. The system includes a gas pipe 8 and a third gas blowing pipe 9. The first gas blowing pipe blows air to the top of both injection tanks simultaneously, the second gas blowing pipe blows air to both annular injection structures simultaneously, and the third gas blowing pipe connects to the bottom of both injection tanks simultaneously. A discharge pipe 21 is connected to the lower side wall of each of the two injection tanks. Both discharge pipes are connected to a secondary gas replenisher 11. A secondary gas replenisher 10 is also led out from the first nitrogen supply pipe. The secondary gas replenisher leads to the secondary gas replenisher. The outlet of the secondary gas replenisher is connected to a centralized pulverized coal pipe 12. The centralized pulverized coal pipe is connected to the blast furnace distributor 19. The blast furnace distributor delivers pulverized coal to the blast furnace 20. An end gas replenisher 18 is also installed on the centralized pulverized coal pipe at the input end of the blast furnace distributor. An end gas replenishment structure is connected to the side wall of the end gas replenisher. Furthermore, the end-gas replenishment structure described in this utility model includes a second nitrogen supply pipe 25, through which nitrogen is introduced and connected to the end-gas replenisher. The second nitrogen supply pipe is sequentially equipped with a manual ball valve 17, a check valve 16, a pneumatic regulating valve 15, a gas flow meter 14, and a pneumatic ball valve 13, with one side of the manual ball valve connected to the end-gas replenisher.

[0023] Furthermore, in this embodiment, a pressure relief pipe 2 is also provided on one side of the top of each injection tank, and the upper end of the pressure relief pipe is connected upward to the pulverized coal silo; a solenoid valve 7 is installed on the pressure relief pipe. Furthermore, in this invention, a branch gas supply pipe 5 is also provided between the second gas supply pipe and the first gas supply pipe outside each injection tank, and a solenoid valve is provided on the branch gas supply pipe. Furthermore, in this invention, solenoid valves are provided on the first gas supply pipe, the second gas supply pipe, and the third gas supply pipe. Furthermore, a solenoid valve is provided on the discharge pipe in this invention. Furthermore, in this invention, the end gas supply device is located at the right-angle bend of the centralized pulverized coal pipe at the input end of the blast furnace distributor.

[0024] like Figure 1As shown, this utility model is integrated into the blast furnace distributor of the blast furnace. Coal powder is injected into the blast furnace through the blast furnace distributor. The end gas supply structure located at the end of the centralized coal powder pipe allows the power medium (nitrogen) to enter. After entering, the gas passes through a pneumatic ball valve, a pneumatic regulating valve, a flow meter, a check valve, and a manual ball valve, and then connects to the end gas supply device to enter the main coal injection pipeline.

[0025] Control Method: The end-point gas supply structure is integrated into the automatic pulverized coal injection program via a control program. The manual ball valve is normally open. To ensure a stable and uniform coal flow in the blast furnace lances and prevent pulsation, the end-point gas supply flow rate is a fixed value. This stability is achieved by controlling the opening of the pneumatic regulating valve through the automatic control module. Upon receiving a blast furnace blast command, the pneumatic ball valve automatically opens, completing the automatic end-point blast operation. During normal blast furnace pulverized coal injection, only the end-point gas supply flow rate value needs to be set; the process control is handled by the automatic control module. Upon receiving a blast furnace shutdown command, the pneumatic ball valve automatically closes, completing the automatic end-point shutdown operation.

[0026] The secondary and terminal air replenishers in this invention are both air replenishers and belong to existing technology. Their structure mainly consists of two flanges, a regulating pipe, a pressure ring, a regulating nut, and valves. Specifically, the air replenisher is usually installed on the main pulverized coal pipe at the outlet of the injection tank for use in the pneumatic conveying of pulverized coal. It allows coal to flow through the inner pipe, while supplementary gas flows through the annular gap formed by the outer and inner pipes, thereby achieving dilution and uniform mixing of the pulverized coal. This invention incorporates relevant air replenishment structures at various locations within the two injection tanks to achieve pneumatic conveying; see details below. Figure 1 Simply connect.

[0027] The application of the end-point gas supply structure significantly promotes the kinetic energy enhancement of the coal flow in the blast furnace pulverized coal injection lance. From a process control perspective, it eliminates the root cause of blockages in the pulverized coal injection lance and related injection pipelines. In practical use, fine-tuning the lance insertion angle effectively reduces coal flow smudging. The adjustment and precise control between the end-point gas supply structure and the secondary gas supply device provide a large adjustment range for fully automatic and precise pulverized coal injection control in the blast furnace, ensuring uniform and accurate pulverized coal injection. The application of the end-point gas supply structure significantly reduces the secondary gas supply flow rate, lowers the consumption of injection power media, increases the injection concentration, reduces the initial flow velocity of pulverized coal in the pipeline, and reduces wear on the injection pipeline. The end-point gas supply structure has broad application prospects in pulverized coal injection systems with a conveying distance exceeding 200m, offering advantages such as low engineering investment and simple process layout. It also has a significant energy-saving effect on the consumption of pulverized coal conveying media. For pulverized coal injection systems with a conveying distance exceeding 400m, multi-stage gas supply systems can be added to achieve better conveying effects.

Claims

1. A blast furnace pulverized coal injection system with an added gas replenishment structure, comprising a pulverized coal silo, characterized in that: Below the pulverized coal bunker, two injection tanks are arranged side by side. Each injection tank has a pulverized coal feed pipe at its top center that connects to the bottom of the pulverized coal bunker. Each injection tank has an annular injection structure at its lower part, which injects air into the corresponding injection tank. A first nitrogen supply pipe is also provided, which simultaneously leads to a first air blowing pipe, a second air blowing pipe, and a third air blowing pipe. The first air blowing pipe simultaneously blows air into the tops of both injection tanks, the second air blowing pipe simultaneously supplies air to both annular injection structures, and the third air blowing pipe simultaneously connects to... It is connected to the bottom of two injection tanks; a discharge pipe is connected to the lower side wall of each of the two injection tanks, and the two discharge pipes are connected to a secondary gas replenisher. A secondary gas replenisher pipe is also led out from the first nitrogen supply pipe. The secondary gas replenisher pipe leads to the secondary gas replenisher. The outlet of the secondary gas replenisher is connected to a centralized pulverized coal pipe, which is connected to the blast furnace distributor. The blast furnace distributor delivers pulverized coal to the blast furnace. An end gas replenisher is also installed on the centralized pulverized coal pipe at the input end of the blast furnace distributor. An end gas replenishment structure is connected to the side wall of the end gas replenisher.

2. The blast furnace pulverized coal injection system with added gas replenishment structure according to claim 1, characterized in that: The end-gas replenishment structure includes a second nitrogen supply pipe, through which nitrogen is introduced and connected to the end-gas replenisher. The second nitrogen supply pipe is sequentially equipped with a manual ball valve, a check valve, a pneumatic regulating valve, a gas flow meter, and a pneumatic ball valve. One side of the manual ball valve is connected to the end-gas replenisher.

3. A blast furnace pulverized coal injection system with an added gas replenishment structure according to claim 1, characterized in that: Each of the aforementioned injection tanks is also provided with a pressure relief pipe on one side of its top, with the upper end of the pressure relief pipe connected upward to the coal powder silo; a solenoid valve is installed on the pressure relief pipe.

4. A blast furnace pulverized coal injection system with an added gas replenishment structure according to claim 1, characterized in that: The annular spray structure includes an annular nozzle, which is installed on the outer wall of the lower part of the corresponding spray tank. Each annular nozzle is evenly spaced with a jet nozzle, which sprays nitrogen gas into the tank through the tank wall of the corresponding spray tank.

5. A blast furnace pulverized coal injection system with an added gas replenishment structure according to claim 1, characterized in that: A branch air supply pipe is also provided between the second air supply pipe and the first air supply pipe on the outside of each blow tank, and a solenoid valve is provided on the branch air supply pipe.

6. A blast furnace pulverized coal injection system with an added gas replenishment structure according to claim 1, characterized in that: Solenoid valves are installed on the first, second, and third air blowing pipes.

7. A blast furnace pulverized coal injection system with an added gas replenishment structure according to claim 1, characterized in that: A solenoid valve is installed on the discharge pipe; a solenoid valve is also installed on the pulverized coal discharge pipe.

8. A blast furnace pulverized coal injection system with an added gas replenishment structure according to claim 1, characterized in that: The end-point gas replenisher is located at the right-angle bend of the centralized pulverized coal pipe at the input end of the blast furnace distributor.

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