Blast furnace pulverized coal injection device stable in coal injection

Abstract

The utility model discloses a blast furnace pulverized coal injection device stable in coal injection, which comprises an injection tank and two coal injection main pipes, a standby tank is arranged below one side of the injection tank, the standby tank is communicated with the injection tank through a communicating pipe, an outlet of the standby tank is respectively communicated with the two coal injection main pipes through coal conveying pipes, and the two coal injection main pipes are communicated with the injection tank through communicating pipes. The other end of each coal injection main pipe is sequentially connected with a coal injection short pipe and a distributor, a standby pipe is arranged between the two coal injection short pipes, a coal injection ball valve is arranged on the standby pipe, a nitrogen branch pipe is arranged below each coal injection main pipe in parallel, the nitrogen branch pipe is connected with a nitrogen main pipe, and the nitrogen main pipe is connected with the distributor. Gas distribution pipes are obliquely arranged between the nitrogen branch pipes and the corresponding coal injection main pipes, the gas outlet ends of the gas distribution pipes are communicated with the bottoms of the coal injection main pipes, the gas outlet directions of the gas distribution pipes obliquely face the coal powder conveying direction in the coal injection main pipes, and nitrogen heaters are arranged on the nitrogen main pipes. In conclusion, the device has the advantages of being not easy to block, good in preheating effect, capable of ensuring smooth operation of the blast furnace and stable in coal injection.

Description

Technical Field

[0001] The utility model relates to the technical field of blast furnace pulverized coal injection, in particular to a blast furnace pulverized coal injection device with stable coal injection. Background Technique

[0002] In the smelting process of a blast furnace, it is necessary to inject pulverized coal into the blast furnace through a blast furnace pulverized coal injection device. Pulverized anthracite, pulverized bituminous coal or a mixture of the two that has been ground fine is directly injected into the furnace from the blast furnace tuyere. In the blast furnace smelting process, it plays the role of providing heat and acting as a reducing agent to replace coke, thereby reducing the coke ratio and the cost of pig iron. Blast furnace coal injection is a major technological revolution in modern blast furnace smelting. More than 90% of pig iron is smelted by blast furnaces injecting fuel.

[0003] The existing blast furnace pulverized coal injection devices are arranged in the form of a group of injection tanks. Most of them are arranged in parallel by two or three injection tanks. One of the injection tanks injects pulverized coal, and the other one or two injection tanks store coal. The two or three injection tanks are used alternately. During the use process, it is found that due to problems such as excessive moisture in the pulverized coal or operational errors, the phenomenon of blockage of the main coal injection pipe often occurs. In order to reduce the losses caused by the blockage of the main coal injection pipe, some enterprises will set up two main coal injection pipes. Each main coal injection pipe transports pulverized coal to the distributor respectively, and then sends it to the tuyere through odd and even branch pipes, so as to reduce the possibility of blockage of the main coal injection pipe. However, after one of the main coal injection pipes is blocked, during the process of dealing with and dredging it, the amount of coal injection inside the blast furnace is affected, and it will still have a greater impact on the stable operation of the blast furnace, causing fluctuations in the quality of hot metal and being unfavorable to the normal progress of subsequent smelting processes. Secondly, the existing blast furnace pulverized coal injection devices generally wind electric heating wires on the outer walls of coal conveying pipes such as the main coal injection pipe, but this method has a poor preheating effect on pulverized coal. Therefore, it is objectively necessary to develop a blast furnace pulverized coal injection device with stable coal injection that is not easy to block, has a good preheating effect, and can ensure the smooth operation of the blast furnace. Content of the Utility Model

[0004] The purpose of the utility model is to provide a blast furnace pulverized coal injection device with stable coal injection that is not easy to block, has a good preheating effect, and can ensure the smooth operation of the blast furnace.

[0005] The object of the present utility model is achieved as follows. It includes a blowing tank and two main pulverized coal pipes. A spare tank is arranged below one side of the blowing tank. The spare tank is communicated with the blowing tank through a connecting pipe. The outlet of the spare tank is respectively communicated with the two main pulverized coal pipes through coal conveying pipes. Gate valves are arranged on the coal conveying pipes. One end of each main pulverized coal pipe is communicated with the outlet of the blowing tank. The other end of each main pulverized coal pipe is successively connected with a short pulverized coal pipe and a distributor. Gate valves are arranged on both the short pulverized coal pipe and the coal conveying pipe. A spare pipe is arranged between the two short pulverized coal pipes. A pulverized coal ball valve is arranged on the spare pipe. A nitrogen branch pipe is arranged in parallel below each main pulverized coal pipe. One end of the nitrogen branch pipe is blocked, and the other end is connected with a nitrogen main pipe. A gas distribution pipe is obliquely arranged between the nitrogen branch pipe and the corresponding main pulverized coal pipe. The gas outlet end of the gas distribution pipe is communicated with the bottom of the main pulverized coal pipe. The gas outlet direction of the gas distribution pipe is obliquely directed towards the pulverized coal conveying direction in the main pulverized coal pipe. A nitrogen heater is arranged on the nitrogen main pipe.

[0006] Further, the gas outlet end of the gas distribution pipe extends into the interior of the main pulverized coal pipe. A purging pipe is arranged on the gas distribution pipe near the bottom of the main pulverized coal pipe. The purging pipe is arranged in parallel with the main pulverized coal pipe.

[0007] Further, a material lifting plate is obliquely arranged at the bottom of the main pulverized coal pipe near the connection between the gas distribution pipe and the main pulverized coal pipe.

[0008] Further, the main pulverized coal pipe includes a thin pipe section, a reduced diameter cone and a thick pipe section that are successively communicated along the pulverized coal conveying direction. The coal conveying pipe is communicated with the thick pipe section.

[0009] Further, a nitrogen conveying pipe is arranged on the nitrogen main pipe at the outlet end of the nitrogen heater. Two short pipes are arranged on the nitrogen conveying pipe. The two short pipes are respectively communicated with the spare pipes on both sides of the pulverized coal ball valve.

[0010] Further, the short pipes are tangentially communicated with the spare pipes.

[0011] When the utility model operates normally, the gate valve on the coal injection short pipe is in the open state, the gate valve on the coal conveying pipe is in the closed state, and the coal injection ball valve is in the closed state. The pulverized coal in the injection tank is divided into two streams and enters the two main coal injection pipes respectively. Then it passes through the coal injection short pipe and the distributor in sequence, and then the pulverized coal is evenly sent into each tuyere of the blast furnace through each outlet branch pipe. The coal injection operations of the two coal injection routes are carried out simultaneously. When the main coal injection pipe on one of the coal injection routes is blocked, the gate valve on the coal injection short pipe of this coal injection route is closed, the gate valve on the coal conveying pipe of the other coal injection route is opened, and the coal injection ball valve is opened at the same time. At this time, the injection tank and the standby tank simultaneously transport pulverized coal to the main coal injection pipe of the other coal injection route, that is, double portions of pulverized coal are transported in the main coal injection pipe of the other coal injection route. The pulverized coal is transported to the coal injection short pipe and is split into two streams when it reaches the standby pipe, so that the pulverized coal is ejected from the two distributors. In the above process, the method of double pipelines and double distributors is adopted, combined with the use of the injection tank and the standby tank. When one main coal injection pipe is blocked, it can be quickly switched to use the other main coal injection pipe to supply the two distributors for injection, and the amount of pulverized coal ejected is the same as that ejected under the normal operating state, ensuring the stability of coal injection, and then being able to maintain the normal operation of the blast furnace, reducing the impact on the blast furnace condition caused by the blockage of the main coal injection pipe, ensuring the smooth running of the blast furnace, and stabilizing the quality of molten iron in the blast furnace. Secondly, a nitrogen branch pipe is provided in the utility model. Nitrogen can be obliquely blown into the main coal injection pipe through the gas distribution pipe, which has two advantages. One is that it can provide and supplement the power for the forward transportation of pulverized coal, prevent the reduction of the pulverized coal transportation speed, so that the pulverized coal can be smoothly delivered to the tuyere of the blast furnace. The other is that it has an upward lifting force on the pulverized coal, which can make the pulverized coal move upward and generate turbulence in the main coal injection pipe, preventing the pulverized coal from sinking and causing the blockage of the pipeline. Through the above method, the accumulation of pulverized coal in the main coal injection pipe can be effectively prevented, so that the main coal injection pipe is not easily blocked, and then the long-term stable operation of the main coal injection pipe is ensured. In addition, the nitrogen is heated by a nitrogen heater before being sent into the main coal injection pipe. After the nitrogen is sprayed into the main coal injection pipe, it can quickly and evenly mix with the pulverized coal and quickly increase the temperature of the pulverized coal. This method has a better preheating effect on the pulverized coal compared with the traditional method of winding electric heating wires on the main coal injection pipe, the heating efficiency of the pulverized coal is higher, and the heat loss is also smaller. To sum up, the utility model has the advantages of not being easily blocked, good preheating effect, ensuring the smooth running of the blast furnace, and stable coal injection. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 is the overall structural schematic diagram of the utility model;

[0013] Figure 2 is the structural schematic diagram of the main coal injection pipe 2, the nitrogen branch pipe 9 and the gas distribution pipe 11 in the utility model;

[0014] In the figure: 1 - injection tank, 2 - main pulverized coal injection pipe, 3 - spare tank, 4 - coal conveying pipe, 5 - short pulverized coal injection pipe, 6 - distributor, 7 - spare pipe, 8 - pulverized coal injection ball valve, 9 - nitrogen branch pipe, 10 - main nitrogen pipe, 11 - gas distribution pipe, 12 - nitrogen heater, 13 - purging pipe, 14 - material lifting plate, 15 - fine pipe section, 16 - thick pipe section, 17 - nitrogen conveying pipe, 18 - short nitrogen injection pipe. Specific implementation manner

[0015] The present invention will be further described below in conjunction with the accompanying drawings, but the present invention is not limited in any way. Any changes or improvements made based on the present invention fall within the protection scope of the present invention.

[0016] As Figures 1-2 shown, the present invention includes an injection tank 1 and two main pulverized coal injection pipes 2. A spare tank 3 is arranged below one side of the injection tank 1. The spare tank 3 is communicated with the injection tank 1 through a connecting pipe. The outlet of the spare tank 3 is respectively communicated with the two main pulverized coal injection pipes 2 through a coal conveying pipe 4. One end of each main pulverized coal injection pipe 2 is communicated with the outlet of the injection tank 1. The other end of each main pulverized coal injection pipe 2 is successively connected with a short pulverized coal injection pipe 5 and a distributor 6. Gate valves are arranged on both the short pulverized coal injection pipe 5 and the coal conveying pipe 4. A spare pipe 7 is arranged between the two short pulverized coal injection pipes 5. A pulverized coal injection ball valve 8 is arranged on the spare pipe 7. A nitrogen branch pipe 9 is arranged in parallel below each main pulverized coal injection pipe 2. One end of the nitrogen branch pipe 9 is blocked, and the other end is connected with a main nitrogen pipe 10. A gas distribution pipe 11 is obliquely arranged between the nitrogen branch pipe 9 and the corresponding main pulverized coal injection pipe 2. The gas outlet end of the gas distribution pipe 11 is communicated with the bottom of the main pulverized coal injection pipe 2. The gas outlet direction of the gas distribution pipe 11 is obliquely oriented towards the pulverized coal conveying direction in the main pulverized coal injection pipe 2. A nitrogen heater 12 is arranged on the main nitrogen pipe 10. The nitrogen heater 12 is an existing device for heating nitrogen.

[0017] When the present invention operates normally, the gate valve on the short pulverized coal injection pipe 5 is in the open state, the gate valve on the coal conveying pipe 4 is in the closed state, and the pulverized coal injection ball valve 8 is in the closed state. The pulverized coal in the injection tank 1 is divided into two streams and enters the two main pulverized coal injection pipes 2 respectively, and then successively passes through the short pulverized coal injection pipe 5 and the distributor 6, and then the pulverized coal is evenly sent into each tuyere of the blast furnace through each outlet branch pipe. The pulverized coal injection operations are carried out simultaneously on the two pulverized coal injection routes. When the main pulverized coal injection pipe 2 on one of the pulverized coal injection routes is blocked, the gate valve on the short pulverized coal injection pipe 5 of this pulverized coal injection route is closed, the gate valve on the coal conveying pipe 4 of the other pulverized coal injection route is opened, and the pulverized coal injection ball valve 8 is opened at the same time. At this time, the injection tank 1 and the spare tank 3 simultaneously send pulverized coal to the main pulverized coal injection pipe 2 of the other pulverized coal injection route, that is, double portions of pulverized coal are conveyed in the main pulverized coal injection pipe 2 of the other pulverized coal injection route. The pulverized coal is conveyed to the short pulverized coal injection pipe 5 and is split into two streams when reaching the spare pipe 7, so that the pulverized coal is ejected from the two distributors 6.

[0018] In the above process, the method of using a dual pipeline and a dual distributor 6 is adopted, combined with the use of the injection tank 1 and the standby tank 3. When one of the coal injection main pipelines 2 is blocked, it can be quickly switched to use the other coal injection main pipeline 2 to supply the two distributors 6 for injection, and the amount of pulverized coal ejected is the same as that in the normal operation state, ensuring the stability of pulverized coal injection. Furthermore, it can maintain the normal operation of the blast furnace, reduce the impact on the blast furnace condition caused by the blockage of the coal injection main pipeline 2, ensure the smooth running of the blast furnace, and stabilize the quality of hot metal in the blast furnace. Secondly, a nitrogen branch pipe 9 is provided in the present utility model. Nitrogen can be obliquely blown into the coal injection main pipeline 2 through the air distribution pipe 11, which has two advantages. One is that it can provide and supplement the power for the forward transportation of pulverized coal, prevent the reduction of the pulverized coal transportation speed, and enable the pulverized coal to be smoothly delivered to the blast furnace tuyere. The other is that it has an upward lifting force on the pulverized coal, which can make the pulverized coal move upward and generate turbulence in the coal injection main pipeline 2, preventing the pulverized coal from sinking and causing pipeline blockage. Through the above method, the accumulation of pulverized coal in the coal injection main pipeline 2 can be effectively prevented, making the coal injection main pipeline 2 not easily blocked, and thus ensuring the long-term stable operation of the coal injection main pipeline 2. In addition, the nitrogen is heated by a nitrogen heater 12 before being sent into the coal injection main pipeline 2. After the nitrogen is sprayed into the coal injection main pipeline 2, it can quickly and evenly mix with the pulverized coal and quickly increase the temperature of the pulverized coal. Compared with the traditional method of winding electric heating wires on the coal injection main pipeline 2, this method has a better preheating effect on the pulverized coal, higher heating efficiency of the pulverized coal, and less heat loss.

[0019] The air outlet end of the air distribution pipe 11 extends into the interior of the coal injection main pipeline 2. A purging pipe 13 is provided on the air distribution pipe 11 near the bottom of the coal injection main pipeline 2. The purging pipe 13 is arranged parallel to the coal injection main pipeline 2. In the actual use process of this device, it is found that there will still be a very small amount of pulverized coal with high humidity, agglomeration, and large particles falling at the bottom of the coal injection main pipeline 2. Over time, it will still accumulate continuously, affecting the normal transportation of pulverized coal. To solve this problem, the purging pipe 13 is provided. Nitrogen will be ejected from the purging pipe 13 and blow the pulverized coal falling at the bottom of the coal injection main pipeline 2 forward. Several purging pipes 13 continuously relay to blow the pulverized coal out of the coal injection main pipeline 2.

[0020] A lifting plate 14 is obliquely arranged at the bottom of the coal injection main pipeline 2 near the connection between the air distribution pipe 11 and the coal injection main pipeline 2. During operation, some nitrogen will be ejected from the purging pipe 13, which can blow the pulverized coal falling at the bottom of the coal injection main pipeline 2, making the pulverized coal move forward. When it encounters the lifting plate 14, it will be lifted upward along the surface of the lifting plate 14 and then be carried away, preventing the pulverized coal from accumulating and causing pipeline blockage.

[0021] The main pulverized coal injection pipe 2 includes a thin pipe section 15, a reducing cone, and a thick pipe section 16 that are sequentially connected along the pulverized coal conveying direction. The coal conveying pipe 4 is connected to the thick pipe section 16. When the main pulverized coal injection pipe 2 on one pulverized coal injection route is blocked, pulverized coal is added to the main pulverized coal injection pipe 2 on another pulverized coal injection route through the standby tank 3. At this time, the main pulverized coal injection pipe 2 on another pulverized coal injection route needs to convey double the amount of pulverized coal. If the diameter of the main pulverized coal injection pipe 2 is too small, it may cause blockage or the conveying capacity may not meet the requirements. To solve this problem, the main pulverized coal injection pipe 2 is set as the thin pipe section 15, the reducing cone, and the thick pipe section 16, and the pulverized coal in the standby tank 3 is introduced into the thick pipe section 16. During design, the flow area of the thick pipe section 16 is made not less than twice the flow area of the thin pipe section 15, which can ensure that the thick pipe section 16 has the required pulverized coal conveying capacity and effectively prevent blockage of the pipeline.

[0022] When the main pulverized coal injection pipe 2 on one pulverized coal injection route is blocked, in order to maintain the smooth operation of the blast furnace, the pulverized coal injection ball valve 8 on the standby pipe 7 is opened, so that the pulverized coal on another pulverized coal injection route can be sent to the distributor 6 of the blocked pulverized coal injection route through the standby pipe 7. However, when the blocked main pulverized coal injection pipe 2 becomes unblocked and the pulverized coal injection device resumes normal operation, the pulverized coal injection ball valve 8 needs to be closed again. At this time, some pulverized coal will remain inside the standby pipe 7. If not cleaned in time, it may cause blockage of the standby pipe 7. To solve this problem, a nitrogen delivery pipe 17 is provided on the main nitrogen pipe 10 at the outlet end of the nitrogen heater 12. Two nitrogen injection short pipes 18 are provided on the nitrogen delivery pipe 17. The two nitrogen injection short pipes 18 are respectively connected to the standby pipe 7 on both sides of the pulverized coal injection ball valve 8. The heated nitrogen is introduced into the nitrogen delivery pipe 17 and then split into the two nitrogen injection short pipes 18, and enters the standby pipe 7 on both sides of the pulverized coal injection ball valve 8 respectively, taking away the pulverized coal inside the standby pipe 7 on both sides of the pulverized coal injection ball valve 8 respectively, achieving the purpose of cleaning the pulverized coal.

[0023] The nitrogen injection short pipe 18 is tangentially connected to the standby pipe 7. The nitrogen injection short pipe 18 is used to introduce nitrogen into the standby pipe 7 to take away the pulverized coal inside the standby pipe 7 to prevent blockage. However, it is found in actual use that there will still be a small amount of pulverized coal falling to the bottom of the standby pipe 7 and not being taken away by nitrogen. To solve this problem, the nitrogen injection short pipe 18 is tangentially connected to the standby pipe 7, so that the nitrogen rotates and flows inside the standby pipe 7, and then can roll up the pulverized coal at various parts inside the standby pipe 7, cleaning the pulverized coal thoroughly and having a better cleaning effect.

Claims

1. A blast furnace pulverized coal injection device with stable pulverized coal injection, comprising a blowing tank (1) and two main pulverized coal pipes (2), characterized in that : A spare tank (3) is arranged below one side of the injection tank (1). The spare tank (3) is communicated with the injection tank (1) through a connecting pipe. The outlet of the spare tank (3) is communicated with two pulverized coal injection main pipes (2) respectively through a coal conveying pipe (4). One end of each pulverized coal injection main pipe (2) is communicated with the outlet of the injection tank (1). The other end of each pulverized coal injection main pipe (2) is successively connected with a pulverized coal injection short pipe (5) and a distributor (6). Gate valves are arranged on both the pulverized coal injection short pipe (5) and the coal conveying pipe (4). A spare pipe (7) is arranged between the two pulverized coal injection short pipes (5). A pulverized coal injection ball valve (8) is arranged on the spare pipe (7). A nitrogen branch pipe (9) is arranged in parallel below each pulverized coal injection main pipe (2). One end of the nitrogen branch pipe (9) is blocked, and the other end is connected with a nitrogen main pipe (10). An air distribution pipe (11) is obliquely arranged between the nitrogen branch pipe (9) and the corresponding pulverized coal injection main pipe (2). The air outlet end of the air distribution pipe (11) is communicated with the bottom of the pulverized coal injection main pipe (2). The air outlet direction of the air distribution pipe (11) is obliquely directed towards the pulverized coal conveying direction in the pulverized coal injection main pipe (2). A nitrogen heater (12) is arranged on the nitrogen main pipe (10).

2. The pulverized coal injection device for blast furnace with stable coal injection according to claim 1, characterized in that : The air outlet end of the air distribution pipe (11) extends into the interior of the pulverized coal injection main pipe (2). A purge pipe (13) is arranged on the air distribution pipe (11) near the bottom of the pulverized coal injection main pipe (2). The purge pipe (13) is arranged in parallel with the pulverized coal injection main pipe (2).

3. The pulverized coal injection device for blast furnace with stable pulverized coal injection according to claim 2, characterized in that : A lifting plate (14) is obliquely arranged at the bottom of the pulverized coal injection main pipe (2) near the connection between the air distribution pipe (11) and the pulverized coal injection main pipe (2).

4. The pulverized coal injection device for blast furnace with stable coal injection according to claim 1, characterized in that : The pulverized coal injection main pipe (2) includes a thin pipe section (15), a reducing cone and a thick pipe section (16) that are successively communicated along the pulverized coal conveying direction. The coal conveying pipe (4) is communicated with the thick pipe section (16).

5. A blast furnace pulverized coal injection device with stable pulverized coal injection according to claim 1, characterized in that : A nitrogen conveying pipe (17) is arranged on the nitrogen main pipe (10) at the outlet end of the nitrogen heater (12). Two nitrogen injection short pipes (18) are arranged on the nitrogen conveying pipe (17). The two nitrogen injection short pipes (18) are respectively communicated with the spare pipes (7) on both sides of the pulverized coal injection ball valve (8).

6. The pulverized coal injection device for blast furnace with stable pulverized coal injection according to claim 5, characterized in that : The nitrogen injection short pipe (18) is tangentially communicated with the spare pipe (7).

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