Method for reducing dust deposition in dry dedusting raw gas pipeline

Abstract

The present application relates to a kind of methods for reducing dry dedusting raw gas pipeline dust, by the inlet branch pipe of box is designed by raw gas main pipe is led out after a distance vertically upward again into horizontal direction into box, reduce the dust of box inlet branch pipe.In the end of raw gas main pipe, new settling tank is added, and the gas outlet pipeline of settling tank is connected with large ash bin, by detecting the temperature difference of pipeline at the end of raw gas main pipe, whether there is dust in pipeline is judged, when there is dust in pipeline, by program control, utilize the pressure difference of raw gas pipeline and settling tank to improve gas flow rate, blast furnace dust in raw gas pipeline is blown into settling tank.The present application realizes the purpose of reducing dry dedusting raw gas pipeline dust by reasonably designing pipeline and adding raw gas pipeline dust removal system.

Description

Technical Field

[0001] This invention relates to a method, specifically a method for reducing ash accumulation in dry dust removal coal gas pipelines, belonging to the technical field of dust removal systems. Background Technology

[0002] The dry dust removal system for blast furnace gas is a secondary dust removal device for blast furnace raw gas. After dry dust removal, the dust content of the blast furnace gas is reduced to 5 mg / m³. 3 The gas then passes through the blast furnace gas residual pressure power generation system or pressure reducing valve group for pressure reduction and cooling before entering the plant's blast furnace gas pipeline network. As the economic and technical indicators of the blast furnace continue to rise, the blast furnace top temperature gradually shows a downward trend, with some domestic blast furnaces already reaching around 100℃. The raw blast furnace gas, starting from the blast furnace riser pipe, undergoes primary dust removal and then secondary dust removal equipment, gradually decreasing in temperature to around 80℃. Water vapor in the raw blast furnace gas gradually condenses and precipitates into liquid water. Under the action of liquid bridge force, the small dust particles in the raw blast furnace gas are transformed into larger dust particles. The larger the dust particle size, the higher the wind speed required for horizontal transport. However, as the temperature of the raw blast furnace gas decreases, under the condition that the blast furnace gas generation rate remains unchanged, the volume of the raw blast furnace gas decreases, and the horizontal flow velocity decreases accordingly. Under the influence of these two factors, ash accumulation is prone to occur in the raw blast furnace gas pipeline of the dry dust removal system.

[0003] Furthermore, the layout of the dry dust removal system for blast furnace gas is generally a two-row parallel arrangement. The main gas pipe branches into two main gas pipes, and branch pipes are then led out from the main gas pipes into the dust collector cylinder. This arrangement creates a blind end at the end of the main gas pipe, where the flow velocity drops to 0 m / s. Dust particles in the blast furnace gas are thrown to the end of the main gas pipe by centrifugal force, forming ash accumulation. If the section near the end is shut down, the area from the branch pipe of the second section near the end to the end of the main gas pipe becomes a blind end, making it prone to ash accumulation. When the section near the end is repaired and needs to be put back into production, it is difficult to operate normally due to the accumulated ash inside the main pipe.

[0004] Currently, the main method involves replacing the gas in the main and branch pipes of the raw coal gas during planned blast furnace maintenance to ensure accessibility before manually cleaning the interior. While this method achieves thorough cleaning, it can only be carried out during planned blast furnace maintenance. Large domestic steel enterprises typically schedule planned blast furnace maintenance only every six months or even a year, making the cleaning frequency insufficient. Therefore, a new solution to address these technical issues is urgently needed. Summary of the Invention

[0005] This invention addresses the problems existing in the prior art by providing a method to reduce ash accumulation in dry dust removal raw coal gas pipelines. The technical solution involves designing the inlet branch pipe of the casing to extend vertically upwards from the main raw coal gas pipe before turning horizontally into the casing, thus reducing ash accumulation in the inlet branch pipe. A settling tank is added at the end of the main raw coal gas pipe, with its gas outlet pipe connected to a large ash silo. By detecting the temperature difference between the upper and lower sections of the pipe at the end of the main raw coal gas pipe, the presence of ash accumulation is determined. When ash accumulation is detected, the gas flow rate is increased by utilizing the pressure difference between the raw coal gas pipeline and the settling tank, through program control, to blow the blast furnace ash from the raw coal gas pipeline into the settling tank. This invention achieves the goal of reducing ash accumulation in dry dust removal raw coal gas pipelines through a rational pipeline design and the addition of a raw coal gas pipeline cleaning system.

[0006] To achieve the above objectives, the technical solution of the present invention is as follows: a method for reducing ash accumulation in dry dust removal coal gas pipelines, characterized in that the method includes the following steps:

[0007] Step 1: Design the layout of the inlet branch pipes of the box in a reasonable way to reduce dust accumulation in the inlet branch pipes;

[0008] Step 2: Install an automatic ash removal system on the main gas pipeline to reduce ash accumulation in the pipeline.

[0009] Step 1 is as follows:

[0010] The inlet branch pipe extends vertically upwards for 2m from directly above the main gas pipe, where an inlet valve is installed. It then extends upwards for another 1m before turning horizontally via a 90° bend and connecting to the housing. With this pipe layout, the thrust exerted by the gas flow velocity in the branch pipe on dust particles is less than the force of gravity. As a result, the dust particles fall into the main gas pipe under the influence of gravity and continue to be pushed horizontally forward by the gas in the main gas pipe. This pipe layout can reduce ash accumulation in the inlet branch pipe.

[0011] Step 2 involves installing an automatic ash removal system on the main raw gas pipe, as follows: A 90° elbow is connected to the end of the main raw gas pipe, turning it vertically. This elbow extends downwards for 1 meter, where an ash removal valve is installed. The pipe then extends downwards for another 2 meters, connecting to the inside of the settling tank. An ash discharge valve is located at the bottom of the settling tank. A gas outlet pipe is installed at the top of the settling tank, connecting to the ash hopper at the bottom of the large ash silo. The large ash silo contains built-in dust collector bags, and a pressure relief valve is connected to the top of the silo. The other end of the pressure relief valve is connected to the low-pressure clean gas main pipe.

[0012] In step 2, two sets of temperature detection devices are installed on both sides of the inlet branch pipe near the end of the main gas pipe to detect the temperature difference between the upper and lower sides of the main gas pipe.

[0013] In step 2,

[0014] An automatic ash removal PLC control program for the main gas pipeline was developed. After repeated field tests and continuous optimization, the program was determined to activate the automatic ash removal program when the difference between two temperature data points in group A or group B of the main gas pipeline exceeds 10℃. This activates the ash discharge valve, the ash unloading valve, the large ash silo pressure relief valve, and the ash removal valve. The program logic is as follows: When the program detects a difference between the temperature data points at the bottom and top of thermocouple a in group A, or between the temperature data points at the bottom and top of thermocouple b in group B, exceeding 10℃, the automatic ash removal program is activated, closing the ash discharge valve and the ash unloading valve, opening the large ash silo pressure relief valve, and then opening the ash removal valve. After the ash removal valve opens, it closes after a 10-second delay, then closes after another 5-minute delay. The program then checks the temperature data points at the bottom and top of thermocouple a in group A, or between the temperature data points at the bottom and top of thermocouple b in group B. If the activation conditions are still met, the above procedure is repeated.

[0015] In step 2, the gas pressure in the raw coal main pipe is above 200 kPa, and the gas pressure in the low-pressure clean coal gas main pipe is below 20 kPa. After the above procedure is executed, the gas in the raw coal main pipe enters the low-pressure clean coal gas main pipe through the ash removal system described in this invention. The pressure difference between the two sides of the ash removal system reaches more than 180 kPa. The ash accumulated at the end of the raw coal gas main pipe can be transported to the ash removal system by airflow. The ash first enters the settling tank and settles under gravity. Some of the suspended dust enters the ash hopper at the bottom of the large ash silo and is filtered by the built-in filter bag in the large ash silo. After the ash removal valve is opened, it closes after a 10-second delay and then after a 5-minute delay. The program detects the difference between the two temperature detection data in group A or group B of the raw coal gas main pipe. If the start-up conditions are still met, the above procedure is repeated. After the automatic ash removal system stops, the ash discharge valve at the bottom of the settling tank is opened to discharge the internal ash.

[0016] Compared to existing technologies, this invention has the following advantages: The method is simple and highly implementable; by optimizing the layout of the inlet branch pipes of the blast furnace, ash accumulation in the inlet branch pipes is reduced; and by installing an automatic ash removal system in the main gas pipe, regular ash removal operations are performed during production. This achieves the goal of reducing ash accumulation in the inlet branch pipes and the main gas pipe, thus facilitating the long-term stable operation of the blast furnace dry dust removal system. The automatic ash removal system described in this invention mainly utilizes the thrust generated by the existing pressure difference in the blast furnace gas pipeline system to clean the ash accumulation in the main gas pipe, requiring no additional energy and resulting in low overall operating costs, making it an economical and reliable method. Attached Figure Description

[0017] Figure 1 : Schematic diagram of the relationship between blast furnace gas pipelines and valves in this invention;

[0018] Figure 2 : Schematic diagram of the dust removal system of this invention;

[0019] Figure 3: Schematic diagram of the control logic of the automatic dust removal system of the present invention.

[0020] In the diagram: 1. Raw coal gas main pipe; 2. Inlet branch pipe of box a; 3. Inlet valve of box a; 4. Box a; 5. Outlet valve of box a; 6. High-pressure clean coal gas main pipe; 7. Ash conveying valve of box a; 8. Ash conveying pipe of box a; 9. Large ash silo; 10. Ash discharge valve of large ash silo; 11. Inlet branch pipe of box b; 12. Inlet valve of box b; 13. Box b; 14. Outlet valve of box b; 15. Ash conveying valve of box b; 16. Ash cleaning valve; 17. Settling tank; 18. Coal gas outlet pipe; 19. Pressure relief valve; 20. Low-pressure clean coal gas main pipe; 21. Ash discharge valve; 22. Lower thermocouple of box a; 23. Upper thermocouple of box a; 24. Lower thermocouple of box b; 25. Upper thermocouple of box b. Detailed Implementation

[0021] To enhance understanding of the present invention, the embodiments will be described in detail below with reference to the accompanying drawings.

[0022] Example 1: See Figure 1 A method for reducing ash accumulation in dry dust removal coal gas pipelines, the method comprising the following steps:

[0023] Step 1: Design the layout of the inlet branch pipes of the box in a reasonable way to reduce dust accumulation in the inlet branch pipes;

[0024] Step 2: Install an automatic ash removal system on the main gas pipeline to reduce ash accumulation in the pipeline.

[0025] Step 1 is as follows:

[0026] The inlet branch pipe extends vertically upwards for 2m from directly above the main gas pipe, where an inlet valve is installed. It then extends upwards for another 1m before turning horizontally via a 90° bend and connecting to the housing. With this pipe layout, the thrust exerted by the gas flow velocity in the branch pipe on dust particles is less than the force of gravity. As a result, the dust particles fall into the main gas pipe under the influence of gravity and continue to be pushed horizontally forward by the gas in the main gas pipe. This pipe layout can reduce ash accumulation in the inlet branch pipe.

[0027] Step 2 involves installing an automatic ash removal system on the main raw gas pipe, as follows: A 90° elbow is connected to the end of the main raw gas pipe, turning it vertically. This elbow extends downwards for 1 meter, where an ash removal valve is installed. The pipe then extends downwards for another 2 meters, connecting to the inside of the settling tank. An ash discharge valve is located at the bottom of the settling tank. A gas outlet pipe is installed at the top of the settling tank, connecting to the ash hopper at the bottom of the large ash silo. The large ash silo contains built-in dust collector bags, and a pressure relief valve is connected to the top of the silo. The other end of the pressure relief valve is connected to the low-pressure clean gas main pipe.

[0028] In step 2, two sets of temperature detection devices are installed on both sides of the inlet branch pipe near the end of the main gas pipe to detect the temperature difference between the upper and lower sides of the main gas pipe.

[0029] In step 2,

[0030] An automatic ash removal PLC control program for the main gas pipeline was developed. After repeated field tests and continuous optimization, the program was determined to activate the automatic ash removal program when the difference between two temperature data points in group A or group B of the main gas pipeline exceeds 10℃. This activates the ash discharge valve, the ash unloading valve, the large ash silo pressure relief valve, and the ash removal valve. The program logic is as follows: When the program detects a difference between the temperature data points at the bottom and top of thermocouple a in group A, or between the temperature data points at the bottom and top of thermocouple b in group B, exceeding 10℃, the automatic ash removal program is activated, closing the ash discharge valve and the ash unloading valve, opening the large ash silo pressure relief valve, and then opening the ash removal valve. After the ash removal valve opens, it closes after a 10-second delay, then closes after another 5-minute delay. The program then checks the temperature data points at the bottom and top of thermocouple a in group A, or between the temperature data points at the bottom and top of thermocouple b in group B. If the activation conditions are still met, the above procedure is repeated.

[0031] In step 2, the gas pressure in the raw coal main pipe is above 200 kPa, and the gas pressure in the low-pressure clean coal gas main pipe is below 20 kPa. After the above procedure is executed, the gas in the raw coal main pipe enters the low-pressure clean coal gas main pipe through the ash removal system described in this invention. The pressure difference between the two sides of the ash removal system reaches more than 180 kPa. The ash accumulated at the end of the raw coal gas main pipe can be transported to the ash removal system by airflow. The ash first enters the settling tank and settles under gravity. Some of the suspended dust enters the ash hopper at the bottom of the large ash silo and is filtered by the built-in filter bag in the large ash silo. After the ash removal valve is opened, it closes after a 10-second delay and then after a 5-minute delay. The program detects the difference between the two temperature detection data in group A or group B of the raw coal gas main pipe. If the start-up conditions are still met, the above procedure is repeated. After the automatic ash removal system stops, the ash discharge valve at the bottom of the settling tank is opened to discharge the internal ash.

[0032] Work process: See Figure 1 Inlet branch pipe 2 extends vertically upwards for 2m from directly above the main gas pipe 1, where inlet valve 3 is installed. It then extends upwards for another 1m before turning horizontally via a 90° bend and connecting to housing 4. Inlet branch pipe 11 extends vertically upwards for 2m from directly above the main gas pipe 1, where inlet valve 12 is installed. It then extends upwards for another 1m before turning horizontally via a 90° bend and connecting to housing 13. The installation method for valves on the remaining housing pipes follows the same principle. With this pipe layout, when the thrust exerted on dust particles by the flow velocity of the raw gas in inlet branch pipes 2 and 11 is less than gravity, the dust particles fall into the main gas pipe 1 under gravity and continue to be pushed horizontally forward by the raw gas in the main gas pipe 1. This pipe layout reduces ash accumulation in inlet branch pipes 2 and 11.

[0033] See Figure 1 — Figure 3 The raw coal gas main pipe 1 is connected to a 90° elbow at its end, turning it vertically and extending downwards for 1m. A cleaning valve 16 is installed thereon, and it extends downwards for another 2m, connecting to the interior of the settling tank 17. The bottom of the settling tank 17 has an ash discharge valve 21. A coal gas outlet pipe 18 is installed on the upper part of the settling tank 17, connecting to the lower ash hopper of the large ash silo 9. The large ash silo 9 contains a dust collector bag, and a pressure relief valve 19 is connected to its upper part. The other end of the pressure relief valve 19 is connected to the low-pressure clean coal gas main pipe 20. A thermocouple 22 is installed below the inlet side of the inlet branch pipe 11 near the end of the raw coal gas main pipe 1, and a thermocouple 23 is installed above the inlet side of the inlet branch pipe 11. The difference between the data measured by thermocouples 23 and 22 is the temperature data for group A. A thermocouple 24 is installed below the end of the raw coal gas main pipe 1 near the end, and a thermocouple 25 is installed above it. The difference between the data measured by thermocouples 24 and 25 is the temperature data for group B. An automatic ash removal PLC control program for the raw coal gas main pipe was developed. After repeated field tests and continuous optimization, the program was determined to be effective when the difference between temperature data from thermocouples 23 and 22 in group A of the raw coal gas main pipe 1, or the difference between two temperature data from thermocouples 24 and 25 in group B, exceeds 10°C. This initiates the automatic ash removal program, closing ash discharge valve 21 and ash unloading valve 10, opening the pressure relief valve 19 of the large ash silo, and opening the ash removal valve 16. The gas pressure inside the raw coal gas main pipe 1 is above 200 kPa, and the gas pressure inside the low-pressure clean coal gas main pipe 20 is below 20 kPa. After executing the above program, the gas in the raw coal gas main pipe 1 enters the low-pressure clean coal gas main pipe 20 through the ash removal system described in this invention. The pressure difference between the two sides of the ash removal system reaches above 180 kPa, allowing the accumulated ash at the end of the raw coal gas main pipe 1 to be transported into the ash removal system via airflow. The accumulated dust first enters the settling tank 17 and settles under the action of gravity. Some of the suspended dust enters the lower ash hopper of the large ash silo 9 and is filtered by the built-in filter bags in the large ash silo.

[0034] After the ash removal valve opens, it closes after a 10-second delay, followed by a 5-minute delay. The program then checks the temperature difference between temperature data couplers 23 and 22 in group 1A of the raw coal gas main or the temperature difference between temperature data couplers 24 and 25 in group B. If the startup conditions are still met, the above procedure is repeated. After the automatic ash removal system stops, the ash discharge valve 21 at the bottom of the settling tank 17 is opened to discharge the accumulated ash.

[0035] It should be noted that the above embodiments are not intended to limit the scope of protection of the present invention. Equivalent transformations or substitutions made based on the above technical solutions all fall within the scope of protection of the claims of the present invention.

Claims

1. A method for reducing ash accumulation in dry dust removal coal gas pipelines, characterized in that, The method includes the following steps: Step 1: Design the layout of the inlet branch pipes of the dust collector housing in a reasonable way to reduce dust accumulation in the inlet branch pipes; Step 2: Install an automatic ash removal system on the main gas pipeline to reduce ash accumulation in the pipeline; Step 1 is as follows: The inlet branch pipe of the dust collector housing is led vertically upwards for 2m from directly above the main gas pipe, where an inlet valve is installed. It then extends upwards for another 1m and turns horizontally through a 90° bend, connecting to the dust collector housing. With this pipe layout, the thrust of the gas flow velocity in the branch pipe on the dust particles is less than the force of gravity. As a result, the dust particles fall into the main gas pipe under the action of gravity and continue to be pushed horizontally forward by the gas in the main gas pipe. This pipe layout can reduce the accumulation of ash in the inlet branch pipe. Step 2: Install an automatic ash removal system on the main gas pipe. Specifically: Connect a 90° elbow at the end of the main gas pipe to make it vertical, extend it downwards for 1m, install an ash removal valve, and then extend it downwards for another 2m to connect to the inside of the settling tank. The bottom of the settling tank is a discharge valve. A gas outlet pipe also needs to be installed on the upper part of the settling tank. The gas outlet pipe is connected to the ash hopper at the bottom of the large ash silo. The large ash silo has a built-in dust collector bag. The upper part of the large ash silo is connected to a pressure relief valve, and the other end of the pressure relief valve is connected to the low-pressure clean gas main pipe.

2. The method for reducing ash accumulation in dry dust removal coal gas pipelines according to claim 1, characterized in that, In step 2, a lower thermocouple (a) is installed below the inlet side of the inlet branch pipe near the end of the main gas pipe, and an upper thermocouple (a) is installed above the inlet side of the inlet branch pipe. The difference between the detection data of the upper thermocouple (a) and the lower thermocouple (a) is the temperature data of group A. A lower thermocouple (b) is installed below the end of the main gas pipe, and an upper thermocouple (b) is installed above it. The difference between the data measured by the upper thermocouple (b) and the lower thermocouple (b) is the temperature data of group B.

3. The method for reducing ash accumulation in dry dust removal coal gas pipelines according to claim 2, characterized in that, In step 2, An automatic ash removal PLC control program for the main gas pipeline was developed. After repeated field tests and continuous optimization, the program was determined to start automatically when the difference between two temperature data points in group A or group B of the main gas pipeline exceeds 10℃. This initiates the automatic ash removal program by closing the ash discharge valve of the settling tank, closing the ash discharge valve of the large ash silo, opening the pressure relief valve of the large ash silo, and opening the ash removal valve. The program logic is as follows: When the program detects that the difference between the temperature data points of the lower and upper thermocouples a in group A, or the temperature data points of the lower and upper thermocouples b in group B, exceeds 10℃, the automatic ash removal program is initiated. This involves closing the ash discharge valve of the settling tank, closing the ash discharge valve of the large ash silo, opening the pressure relief valve of the large ash silo, and opening the ash removal valve. After the ash removal valve opens, it closes after a 10-second delay, followed by a 5-minute delay. The program then checks the difference between the temperature data points of the lower and upper thermocouples a in group A, or the difference between the temperature data points of the lower and upper thermocouples b in group B. If the activation conditions are still met, the above procedure is repeated.

4. The method for reducing ash accumulation in dry dust removal coal gas pipelines according to claim 3, characterized in that, In step 2, the gas pressure in the raw coal main pipe is above 200 kPa, and the gas pressure in the low-pressure clean coal gas main pipe is below 20 kPa. After the above procedure is executed, the gas in the raw coal main pipe enters the low-pressure clean coal gas main pipe through the ash removal system. The pressure difference between the two sides of the ash removal system reaches more than 180 kPa. The ash accumulated at the end of the raw coal gas main pipe can be transported to the ash removal system by airflow. The ash first enters the settling tank and settles under gravity. Some of the suspended dust enters the ash hopper at the bottom of the large ash silo and is filtered by the built-in filter bag in the large ash silo. After the ash removal valve is opened, it closes after a 10-second delay and then after a 5-minute delay. The program detects the difference between the two temperature detection data in group A or group B of the raw coal gas main pipe. If the start-up conditions are still met, the above procedure is repeated. After the automatic ash removal system stops, the ash discharge valve of the settling tank is opened to discharge the internal ash.

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