Needle coke calcination pretreatment system and method
Through screening, crushing and dehydration treatment in the needle-shaped coke calcination pretreatment system, the problems of high moisture content and uneven particle size of needle-shaped coke are solved, calcination uniformity and product quality are improved, and energy consumption is reduced.
Patent Information
- Application Number
- CN202510357811.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-25
- Publication Date
- 2025-06-17
AI Technical Summary
The high moisture content and uneven particle size of needle-shaped coke lead to increased energy consumption during calcination, unstable product quality, and it is difficult to form a good needle-shaped structure.
The properties and treatment processes of needle-shaped coke before calcination are optimized by screening, crushing, dehydration and other methods. Through a combination of a series of conveyors, drainage silos, screening machines and crushers, the particle size uniformization and moisture reduction of needle-shaped coke are achieved.
It improves the uniformity of calcination, avoids local overheating or supercooling, and obtains needle-shaped coke products with better performance, while reducing moisture in the raw materials, reducing heat consumption, and improving the fluidity of the raw materials.
Smart Images
Figure CN120158320A_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the technical field of pre-treatment of needle coke calcination, and particularly relates to a pre-treatment system and method for needle coke calcination. Background Art
[0002] Needle coke is a product after calcination of green coke and is an important raw material for electric arc furnace steelmaking. With the rapid development of China's steel industry, ordinary electric furnaces are gradually phased out, while large-capacity electric furnaces are increasing day by day. The demand for ultra-high power graphite electrodes with a diameter of Φ300 - 700mm has increased rapidly. Ultra-high power graphite electrodes mainly use needle coke as the main raw material. There are few domestic production enterprises, and the quality is not ideal, mainly relying on imports.
[0003] High moisture content and uneven particle size of needle coke raw materials will significantly affect product quality. During the heating and vaporization process of the moisture in needle coke, it will increase the fuel consumption and the load of the vacuum pumping system, increasing the energy consumption of the entire production system; during the gasification reaction process of liquid water, cracks and pores will be generated from a macroscopic perspective, and phase changes and molecular arrangements will occur from a microscopic perspective, interfering with the generation, growth, and coalescence processes of mesophase spheres and making it difficult to form a good needle-like structure; moisture may carry some impurities, affecting the purity and quality of the product.
[0004] The particle size of needle coke is uneven. During the kneading process, it is difficult to mix unevenly sized needle coke with other raw materials such as binders; during the molding process, uneven particle size will cause uneven filling of the material in the mold. Large particles may block the mold channels or cause local accumulation, while small particles may fill the gaps between large particles, resulting in poor dimensional accuracy and uneven surface of the molded electrode, and even defects such as material shortage and voids. During the roasting process, due to uneven heating of unevenly sized needle coke, the volatiles will be discharged unevenly. The volatiles inside large particles may be difficult to be completely discharged, while small particles may be overheated, thus affecting the quality of the roasted electrode, such as uneven density and inconsistent hardness. Summary of the Invention
[0005] In view of the above-mentioned disadvantages and deficiencies of the prior art, the present invention provides a pre-treatment system and method for needle coke calcination, which optimize the properties and treatment process of needle coke before calcination through methods such as screening, crushing, and dehydration.
[0006] In order to achieve the above object, the main technical solutions adopted by the present invention include: A pre-treatment system for calcining needle coke, comprising a first conveyor, the discharge end of the first conveyor is connected to the feed end of a positive three-way reversing valve, one discharge end of the positive three-way reversing valve is connected to the feed end of a first water-draining bin, the other discharge end of the positive three-way reversing valve is connected to a second conveyor, the second conveyor has two transportation channels, one transportation channel is connected to the feed end of a four-way reversing valve, the discharge of the four-way reversing valve is connected to the feed end of a second water-draining bin, the other transportation channel is connected to the feed end of a third water-draining bin, the bottom of the water-draining bin is provided with a drainage pipeline and a discharge pipeline, the discharge of the discharge pipeline is connected to a vibrating conveyor, an electric slide valve is provided on the discharge pipeline, the discharges of the three vibrating conveyors are all connected to a screening machine through a third conveyor, the discharge end of the oversize material of the screening machine is connected to a crusher, the discharge end of the crusher and the discharge end of the undersize material of the screening machine are connected to the feed end of a weighing bin through a fourth conveyor, the discharge end of the weighing bin is connected to a metering feeder, a manual valve is provided on the discharge pipeline of the weighing bin, the discharge end of the metering feeder is connected to a side three-way reversing valve, one discharge end of the side three-way reversing valve is connected to a dryer through a star feeder valve, and the other discharge end of the side three-way reversing valve is a sampling end.
[0007] Further, the first conveyor, the second conveyor, the third conveyor, and the fourth conveyor are belt conveyors or elevators.
[0008] Further, the first water-draining bin, the second water-draining bin, and the third water-draining bin discharge the material after reducing the water content of the needle coke green coke to 8% - 12%.
[0009] Further, the angle of the bottom discharge hopper of the first water-draining bin, the second water-draining bin, and the third water-draining bin is 60°.
[0010] Further, level gauges are provided in the first water-draining bin, the second water-draining bin, and the third water-draining bin.
[0011] Further, the feed particle size of the screening machine is ≤ 70 mm, the oversize material particle size is 8 - 70 mm, and the undersize material particle size is < 8 mm.
[0012] Further, the feed particle size of the crusher is 8 - 70 mm, and the particle size after crushing is < 8 mm.
[0013] Further, the dryer discharges the material after reducing the water content of the needle coke green coke to 5% or less.
[0014] The method for pretreating needle coke before calcination using the described system is as follows: The green needle coke is transported to the positive three-way reversing valve by the first conveyor. The green coke enters the first water drainage bin through one of the discharge ends of the positive three-way reversing valve. When the material in the first water drainage bin reaches the set target, the green coke enters the second conveyor through the other discharge end of the positive three-way reversing valve, and is first transported to the second water drainage bin through the four-way reversing valve. After the material in the second water drainage bin reaches the set target, the four-way reversing valve changes direction to make the material enter the second conveyor and be transported to the third water drainage bin. The discharged material after water drainage in the water drainage bin is transported to the third conveyor by the vibrating conveyor. The third conveyor transports the material to the screening machine. The material on the screen of the screening machine after being crushed by the crusher and the material under the screen of the screening machine are transported to the weighing bin by the fourth conveyor. The discharged material from the weighing bin enters the dryer through the metering feeder, metering feeder, side three-way reversing valve, and star feeder valve.
[0015] Further, the green needle coke is transported to the feeding end of the first conveyor by the grab crane.
[0016] The beneficial effects of the present invention are: The needle coke calcination pretreatment system and method provided by the present invention can make the product particle size uniform, which is beneficial to improving the calcination uniformity, avoiding local overheating or overcooling, and thus obtaining a needle coke product with better performance. In addition, the system and method of the present invention can not only reduce the moisture in the raw material and reduce the heat consumed during the moisture evaporation process, but also make the raw material finer and more uniform, improving the fluidity of the raw material. The present invention can optimize the properties of the raw material, improve the production efficiency, and ensure the stable quality of the product for the pretreatment of needle coke before calcination. Brief Description of the Drawings
[0017] Figure 1 It is a schematic diagram of the needle coke calcination pretreatment system of the present invention.
[0018] In the figure: 1. Grab crane; 2. First conveyor; 3. Positive three-way reversing valve; 4. Four-way reversing valve; 5. First water drainage bin; 6. Electric slide valve; 7. Vibrating conveyor; 8. Screening machine; 9. Crusher; 10. Weighing bin; 11. Manual valve; 12. Metering feeder; 13. Side three-way reversing valve; 14. Star feeder valve; 15. Dryer; 16. Second conveyor; 17. Third conveyor; 18. Fourth conveyor; 19. Second water drainage bin; 20. Third water drainage bin. Detailed Embodiments
[0019] In order to better explain the present invention for easy understanding, the present invention will be described in detail below with reference to the drawings and through specific embodiments.
[0020] The present invention provides a needle coke calcination pretreatment system and method, as Figure 1As shown in the figure, the pre-treatment system for calcining needle coke provided by the present invention includes a first conveyor 2. The discharge end of the first conveyor 2 is connected to the feed end of a positive three-way reversing valve 3. Specifically, the green needle coke is transported to the feed end of the first conveyor 2 by a grab crane 1. One discharge end of the positive three-way reversing valve 3 is connected to the feed end of a first water drainage bin 5, and the other discharge end of the positive three-way reversing valve 3 is connected to a second conveyor 16. The second conveyor 16 has two transportation channels. One transportation channel is connected to the feed end of a four-way reversing valve 4, and the discharge of the four-way reversing valve 4 is connected to the feed end of a second water drainage bin 19. The other transportation channel is connected to the feed end of a third water drainage bin 20. Since the second conveyor 16 is arranged above the water drainage bin, a four-way reversing valve 4 is arranged above the second water drainage bin 19. Two of the ports of the four-way reversing valve 4 are discharge ends, which can be arranged on both sides of the second conveyor 16 above the second water drainage bin 19, so that the material enters the second water drainage bin 19 along both sides of the second water drainage bin 19, which can avoid the feed of the second water drainage bin 19 deviating to one side due to feeding from one side. The angles of the bottom discharge hoppers of the first water drainage bin 5, the second water drainage bin 19, and the third water drainage bin 20 are 60°, which can better assist in draining water and discharging materials of the green coke with a higher water content. The first water drainage bin 5, the second water drainage bin 19, and the third water drainage bin 20 are provided with level gauges. Specifically, they can be radar level gauges, which are connected to the control system. When the material in the water drainage bin reaches the set height, the feeding is stopped, and the valves of the corresponding positive three-way reversing valve 3 and four-way reversing valve 4 are controlled to open and close. Sensors for bearing the water drainage bin are also arranged in the water drainage bin. Drainage pipelines and discharge pipelines are arranged at the bottoms of the three water drainage bins. The discharge of the discharge pipeline is connected to a vibrating conveyor 7. An electric slide valve 6 is arranged on the discharge pipeline. The discharges of the three vibrating conveyors 7 are all connected to a screening machine 8 through a third conveyor 17. The discharge end of the oversize material of the screening machine 8 is connected to a crusher 9. The discharge end of the crusher 9 and the discharge end of the undersize material of the screening machine 8 are connected to the feed end of a weighing bin 10 through a fourth conveyor 18. The discharge end of the weighing bin 10 is connected to a metering feeder 12. A manual valve 11 is arranged on the discharge pipeline of the weighing bin 10. The discharge end of the metering feeder 12 is connected to a side three-way reversing valve 13. One discharge end of the side three-way reversing valve 13 is connected to a dryer 15 through a star feeder valve 14, and the other discharge end of the side three-way reversing valve 13 is a sampling end. Specifically, the first conveyor 2, the second conveyor 16, the third conveyor 17, and the fourth conveyor 18 are belt conveyors or elevators.
[0021] The electrical equipment in the system of the present invention, such as the grab crane 1, conveyors, vibrating feeders, vibrating screens, crushers, metering feeders, dryers, valves, radar level gauges of the water drainage bins, and sensors of the weighing bins, can all be connected to the existing control system to achieve automatic control.
[0022] The present invention also provides a method for pre-treatment of needle coke before calcination using the said system, which includes that the green needle coke is transported to the raw material station by truck, the stored green coke in the warehouse is used, and the grab crane 1 is used to pour the green coke with a relatively high water content into the feeding end of the first conveyor 2. The first conveyor 2 transports the green needle coke to the positive three-way reversing valve 3. The green coke enters the first water drainage bin 5 through one of the discharge ends of the positive three-way reversing valve 3. When the material in the first water drainage bin 5 reaches the set target, the green coke enters the second conveyor 16 through the other discharge end of the positive three-way reversing valve 3, and is first transported to the second water drainage bin 19 through the four-way reversing valve 4. After the material in the second water drainage bin 19 reaches the set target, the four-way reversing valve 4 changes its direction to make the material enter the second conveyor 16 and be transported to the third water drainage bin 20. The material is statically stored in the first water drainage bin 5, the second water drainage bin 19 and the third water drainage bin 20, and the water content of the green needle coke is reduced to 8%-12% before discharging. Specifically, it can be reduced to 10% before discharging. The electric slide valve 6 is remotely opened, and the discharged material after water drainage in the water drainage bin is transported to the third conveyor 17 through the vibrating conveyor 7. The third conveyor 17 transports the material to the screening machine 8. The discharged material after the screening machine 8 screens the oversize material and crushes it through the crusher 9 and the discharged material of the undersize material of the screening machine 8 are transported to the weighing bin 10 through the fourth conveyor 18. The feeding particle size of the green needle coke of the present invention is ≤70mm, the feeding particle size of the material before entering the screening machine 8 is ≤70mm, the oversize material particle size is 8-70mm, the undersize material particle size is <8mm, the feeding particle size of the crusher 9 is 8-70mm, and the crushed particle size is <8mm. The discharged material of the weighing bin 10 enters the dryer 15 through the metering feeder 12, the metering feeder 12, the side three-way reversing valve 13 and the star feeder 14. The side discharge port of the side three-way reversing valve 13 is the sampling port for sampling, testing the water content, etc. The dryer 15 discharges the material after reducing the water content of the green needle coke to 5% or less, and the dried green coke is sent to the next process through the belt conveyor.
[0023] The needle coke treatment system and method of the present invention screen, crush, initially dehydrate and secondarily dehydrate the green coke with a relatively high water content. The system and method of the present invention can not only reduce the moisture in the raw material and reduce the heat consumed during the moisture evaporation process, but also make the raw material finer and more uniform, and improve the fluidity of the raw material. The present invention can optimize the properties of the raw material, improve the production efficiency and ensure the stable product quality for the pre-treatment of needle coke before calcination. The present invention is not only applicable to the raw material pretreatment of the needle coke calcination process, but also applicable to industries and fields such as non-ferrous metallurgy and carbon that contain a calcination section.
[0024] Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Any modifications, alterations, substitutions and variations made by those of ordinary skill in the art to the above embodiments fall within the scope of the present invention.
Claims
1. A needle coke calcination pretreatment system, characterized in that: The invention comprises a first conveyor (2), wherein the discharge end of the first conveyor (2) is connected to the feed end of a positive three-way reversing valve (3), one of the discharge ends of the positive three-way reversing valve (3) is connected to the feed end of a first draining bin (5), and the other discharge end of the positive three-way reversing valve (3) is connected to a second conveyor (16), and the second conveyor (16) has two transport channels, one of which is connected to the feed end of a four-way reversing valve (4), the discharge of the four-way reversing valve (4) is connected to the feed end of a second draining bin (19), and the other transport channel is connected to the feed end of a third draining bin (20), a drainage pipeline and a discharge pipeline are provided at the bottom of the draining bin, the discharge of the discharge pipeline is connected to a vibrating conveyor (7), and an electric plug plate is provided on the discharge pipeline. The discharges of the three vibrating conveyors (7) are connected to the screening machine (8) via the third conveyor (17); the discharge end of the screened material of the screening machine (8) is connected to the crusher (9); the discharge end of the crusher (9) and the discharge end of the screened material of the screening machine (8) are connected to the feed end of the weighing bin (10) via the fourth conveyor (18); the discharge end of the weighing bin (10) is connected to the quantitative feeder (12); a manual valve (11) is provided on the discharge pipeline of the weighing bin (10); the discharge end of the quantitative feeder (12) is connected to the side three-way reversing valve (13); one discharge end of the side three-way reversing valve (13) is connected to the drying machine (15) via the star-shaped feeding valve (14); the other discharge end of the side three-way reversing valve (13) is the sampling end.
2. The needle coke calcination pretreatment system according to claim 1, characterized in that: The first conveyor (2), the second conveyor (16), the third conveyor (17), and the fourth conveyor (18) are belt conveyors or elevators.
3. The needle coke calcination pretreatment system according to claim 1, characterized in that: The first drain bin (5), the second drain bin (19), and the third drain bin (20) reduce the moisture content of the needle coke to 8%-12% before discharging the coke.
4. The needle coke calcination pretreatment system according to claim 1, characterized in that: The discharge hopper angles at the bottoms of the first drain bin (5), the second drain bin (19) and the third drain bin (20) are 60°.
5. The needle coke calcination pretreatment system according to claim 1, characterized in that: Material level meters are provided in the first drain bin (5), the second drain bin (19), and the third drain bin (20).
6. The needle coke calcination pretreatment system according to claim 1, characterized in that: The feed particle size of the screening machine (8) is ≤70 mm, the particle size of the material on the screen is 8-70 mm, and the particle size of the material under the screen is <8 mm.
7. The needle coke calcination pretreatment system according to claim 1, characterized in that: The feed particle size of the crusher (9) is 8-70 mm, and the particle size after crushing is less than 8 mm.
8. The needle coke calcination pretreatment system according to claim 1, characterized in that: The dryer (15) reduces the moisture content of the needle coke to 5% or less and then discharges the material.
9. A method for pre-treatment of needle coke calcination using the system according to any one of claims 1 to 8, characterized in that: The needle coke raw coke is transported to the positive three-way reversing valve (3) via the first conveyor (2), and the raw coke enters the first drain bin (5) via one of the discharge ends of the positive three-way reversing valve (3). When the material in the first drain bin (5) reaches a set target, the raw coke enters the second conveyor (16) via the other discharge end of the positive three-way reversing valve (3), and is first transported to the second drain bin (19) via the four-way reversing valve (4). When the material in the second drain bin (19) reaches a set target, the four-way reversing valve (4) is reversed to allow the material to enter the second conveyor (16) for transportation. The material is conveyed to the third drain bin (20) after being drained from the drain bin via a vibrating conveyor (7) to a third conveyor (17). The third conveyor (17) conveys the material to a screening machine (8). The material on the screen of the screening machine (8) is crushed by a crusher (9) and the material under the screen of the screening machine (8) is conveyed to a weighing bin (10) via a fourth conveyor (18). The material on the weighing bin (10) is conveyed to a dryer (15) via a quantitative feeder (12), a side three-way reversing valve (13), and a star-shaped feeder valve (14).
10. The method for pre-treatment of needle coke calcination according to claim 9, characterized in that: The green needle coke is transported to the feed end of the first conveyor (2) via a grab crane (1).