Hot multi-stage impurity removal device with magnetic medium temperature control for continuous production of calcined petroleum coke

Abstract

The application belongs to the technical field of carbon material purification and magnetic separation equipment, and relates to a hot multi-stage impurity removal device with magnetic medium temperature control for continuous production of calcined petroleum coke. The device is aimed at the long-term technical contradiction of the industry, that is, high efficiency of hot-state impurity removal but easy high-temperature demagnetization of magnetic medium, stable cold-state impurity removal equipment but low efficiency and high energy consumption. The device innovatively adopts a reverse double-cooling magnetic separation structure with an inner tube core cooling and an outer jacket global wrapping, cooperates with high-speed scattering and depolymerization, two-stage hot-state grading screening, two-stage gradient magnetic separation, full-closed nitrogen-filling protection and an intelligent closed-loop temperature control system, and realizes continuous and efficient impurity removal of 300-500 DEG C hot-state calcined petroleum coke. The device can stably control the global working temperature of the magnetic medium within 120 DEG C, and the magnetic strength annual decay rate is less than or equal to 2%. The device has reasonable structure, stable operation and high purification precision, and has multiple advantages of efficient impurity removal, energy saving and consumption reduction and long service life, and is suitable for large-scale continuous production of high-end calcined petroleum coke for negative electrodes of lithium batteries.

Description

Technical Field

[0001] This invention relates to the technical field of magnetic separation and purification equipment, and more particularly to a hot-state multi-stage impurity removal device with magnetic medium temperature control for continuous production of calcined petroleum coke. Background Technology

[0002] Calcined petroleum coke is a core precursor for artificial graphite anode materials. The content of magnetic metal impurities such as iron, nickel, cobalt, and copper in it directly determines the cycle life, rate performance, and safety performance of lithium batteries. As power lithium batteries iterate towards higher energy density and higher safety, the total metal impurity requirement for calcined petroleum coke used in high-end anodes has been reduced to below 30 ppm, which places extremely high demands on purification processes and equipment.

[0003] High-gradient magnetic separation is the mainstream technology for removing magnetic metal impurities from calcined petroleum coke. However, current industrial applications all adopt the cold offline magnetic separation mode, that is, the high-temperature material after calcination is first cooled to room temperature and then transported to the magnetic separation process for impurity removal. This mode has three inherent defects that are difficult to overcome: the temperature of the material after calcination is as high as 300~500℃, and a large amount of high-quality sensible heat is directly lost during the cooling process and cannot be effectively recovered and utilized, resulting in serious energy waste. The waste heat per ton of product is equivalent to about 20kg of standard coal, which is contrary to the green manufacturing requirements under the dual carbon target.

[0004] Meanwhile, the impurity removal efficiency of high gradient magnetic separation is low. During the material cooling process, the ultrafine coke powder agglomerates and coats, encapsulating metal impurity particles inside the agglomerates. During the magnetic separation process, the magnetic field cannot effectively act on the encapsulated metal particles, resulting in a total metal impurity removal rate of only 50-60%. To meet the purity requirements, repeated magnetic separation is required, resulting in low production efficiency and large yield loss.

[0005] Furthermore, the production process is lengthy, with each step—cooling, transfer, and magnetic separation—being set up independently. The process is lengthy, occupies a large area, and has a low degree of automation, making it difficult to seamlessly integrate with continuous calcination production lines and hindering the improvement of production efficiency.

[0006] To address the aforementioned issues, the industry has attempted to directly employ hot magnetic separation to retain residual heat and improve impurity removal efficiency. However, it has consistently faced insurmountable technical bottlenecks: the core magnetic media of high-gradient magnetic separators are mostly equipped with neodymium iron boron permanent magnets or excitation magnetic guide steel wool. The Curie temperature of neodymium iron boron is only around 310℃, and its magnetic properties begin to irreversibly decay when the actual operating temperature exceeds 120℃, and it will rapidly demagnetize and fail above 300℃. Even with electromagnetic magnetic separation, high temperatures can lead to coil insulation aging, increased resistance, and a dramatic increase in energy consumption. Therefore, the high impurity removal efficiency of hot materials and the long-term stable operation of the magnetic media have created a common industry contradiction that is difficult to reconcile, leading to a widespread technical prejudice in the industry that "hot magnetic separation can only be used for short-term trials and cannot be industrialized for long-term operation."

[0007] Existing publicly available technologies have also explored high-temperature magnetic separation to some extent: for example, some patents disclose high-temperature material magnetic separators, which only have a simple water-cooling jacket on the outer shell of the magnetic separator. This cannot accurately cool the core filling area of ​​the magnetic medium, and the core temperature inside the magnetic medium still far exceeds the safety threshold. Moreover, the cooling uniformity is poor, the magnetic field distribution is disordered, and the impurity removal effect fluctuates greatly. There are also patents that disclose multi-stage demagnetization systems for calcined petroleum coke, which are all designed based on cold working conditions and do not involve hot magnetic separation and temperature control protection structures. Another solution uses high-temperature resistant permanent magnet materials, but the material cost increases exponentially, and the magnetic field strength is insufficient to meet the requirements for deep impurity removal.

[0008] In summary, there is currently no mature dedicated equipment that can simultaneously achieve the three major goals of efficient hot impurity removal, long-life stable operation of magnetic media, and continuous closed production throughout the entire process. This severely restricts the technological upgrading of continuous, low-energy-consumption, and high-quality production of calcined petroleum coke. Summary of the Invention

[0009] The purpose of this invention is to overcome the shortcomings of the prior art, systematically solve the three major common problems in the preparation of calcined petroleum coke, and provide a hot multi-stage impurity removal device with magnetic medium temperature control for continuous production of calcined petroleum coke. This device significantly improves product purity and structural stability while achieving long-cycle, low-energy consumption, large-scale continuous and stable production.

[0010] The technical solution adopted by this invention to solve its technical problem is: A multi-stage hot impurity removal device with magnetic medium temperature control for continuous production of calcined petroleum coke, comprising the following components connected in series along the material flow direction: The system includes a feeding buffer and dispersing unit, a two-stage hot vibrating screening unit, a two-stage temperature-controlled high-gradient magnetic separation unit, and a closed discharge conveying unit. The entire device is equipped with a sealed, insulated outer shell and is equipped with an independent circulating cooling temperature control unit and an inert gas protection unit. The two-stage temperature-controlled high-gradient magnetic separation unit consists of a first-stage coarse high-gradient magnetic separator and a second-stage fine high-gradient magnetic separator, forming a gradient impurity removal system. Each magnetic separator is equipped with a magnetic medium component and a magnetic medium filling layer. A sealed jacketed cooling cavity is set around the magnetic medium component. Multiple sets of cooling pipes are arranged inside the magnetic medium filling layer. The jacketed cooling cavity and the cooling pipes are connected to form a dual cooling circuit. The circulating cooling temperature control unit is connected to the dual cooling circuit and is used for forced cooling and temperature control of the magnetic medium component. After being fed and dispersed, deagglomerated, and classified by two-stage screening, the hot-calcined petroleum coke is kept at a high temperature and then passed through two-stage temperature-controlled magnetic separation units to complete deep impurity removal. The magnetic media components maintain a safe operating temperature under the hot working conditions of the material.

[0011] As a preferred embodiment of the invention, the feeding buffer and dispersing unit includes an insulated feeding chute, a conical buffer hopper, and a high-speed dispersing roller; The inner lining of the insulated feed chute is made of wear-resistant ceramic, and the outer wall is covered with an insulation layer. It is sealed and connected to the discharge port of the vertical continuous calcining furnace. The other end of the insulated feed chute is connected to the conical buffer silo. The high-speed dispersing roller is horizontally positioned at the outlet of the conical buffer hopper. The roller surface is arranged with staggered dispersing teeth. The rotation speed is 300~600 r / min. The high-speed dispersing roller is equipped with bearing seats at both ends and external water-cooling jackets.

[0012] As a preferred embodiment of the invention, the two-stage hot vibrating screen unit includes a primary hot vibrating screen 3 and a secondary hot vibrating screen 4; the screen aperture size of the primary hot vibrating screen is 6~10mm, used to remove large particle agglomerates; the screen aperture size of the secondary hot vibrating screen is 0.05~0.1mm, and an ultrasonic screen cleaning device is equipped at the bottom of the screen plate to remove ultrafine coke powder; both vibrating screens are fully enclosed and insulated structures, and the screen box and pipeline are sealed with high-temperature resistant flexible connections.

[0013] As a preferred embodiment of the invention, the cooling tubes are inserted into the magnetic medium filling layer with a spacing of 20~60mm between the tubes; cooling water enters the cooling tubes from the bottom to exchange heat with the core area of ​​the magnetic medium, then flows into the outer jacket cooling cavity and upwards, and is discharged from the top, forming a dual cooling circuit with reverse heat exchange, so that the temperature deviation in the magnetic medium filling layer is ≤±5℃.

[0014] As a preferred embodiment of the invention, the background magnetic field strength of the primary coarsening high-gradient magnetic separator is 9000~13000Gs, and the material flow rate is 0.6~1.0m / s, used to remove large-particle strongly magnetic iron impurities; the background magnetic field strength of the secondary cleaning magnetic separator is 16000~22000Gs, and the material flow rate is 0.3~0.6m / s, used to deeply remove fine-particle weakly magnetic metal impurities.

[0015] As a preferred embodiment of the invention, the circulating cooling temperature control unit includes an industrial chiller, a water distributor, a water collector, an electric flow regulating valve, and a temperature control module; multiple temperature sensors are arranged inside the magnetic media component, and the temperature control module automatically adjusts the cooling water flow and inlet water temperature according to the real-time feedback of the temperature sensors, and controls the magnetic media working temperature in a closed loop within the range of 100~120℃. The temperature sensor is electrically connected to the circulating cooling temperature control unit.

[0016] As a preferred embodiment of the invention, the inert gas protection unit is filled with high-purity nitrogen from multiple points including feeding, screening, and magnetic separation. The device maintains a slight positive pressure and controls the oxygen content to below 1%, preventing the high-temperature materials from oxidizing and burning.

[0017] As a preferred embodiment of the invention, the closed discharge conveying unit includes an insulated discharge chute and a closed conveying device. The discharge chute is sealed to the concentrate outlet of the secondary magnetic separator, and the subsequent waste heat recovery process is carried out directly. The total temperature loss of the material throughout the entire process is ≤50℃.

[0018] As a preferred embodiment of the invention, the discharge end is equipped with an online metal detection unit to detect the metal impurity content of the finished product in real time. The data is fed back to the magnetic separation control system, which automatically adjusts the magnetic field strength and material flow rate to form a closed-loop control of product quality.

[0019] As a preferred embodiment of the invention, when processing petroleum coke calcined at 300~500℃, the total metal impurity removal rate is ≥85%, the total metal impurities in the finished product are ≤20ppm, and the annual magnetic intensity decay rate of the magnetic medium is ≤2%.

[0020] The beneficial effects of this application are as follows: 1. Breaking through industry technical biases, this application achieves a win-win situation of efficient hot-state impurity removal and long lifespan of magnetic media. It is the first to create a reverse dual cooling structure with internal core cooling and full-area outer jacket wrapping. This structure directly penetrates the core area of ​​the magnetic media for uniform heat exchange, breaking through the bottleneck of simple shell cooling. It can stably control the working temperature of the magnetic media under hot conditions of 300~500℃ to within 120℃, with excellent temperature uniformity and an annual magnetic intensity decay rate of ≤2%. The service life of the equipment is comparable to that of cold-state magnetic separation. At the same time, the material is kept hot throughout the process. With the pre-dispersion and deagglomeration, there is no coke powder agglomeration and the metal impurities are fully exposed. The total metal impurity removal rate can reach more than 90%, which is 35% higher than that of traditional cold-state magnetic separation. This fundamentally solves the long-standing technical contradiction that efficiency and lifespan cannot be achieved at the same time, and achieves unexpected technical results.

[0021] 2. The entire process of dispersing, screening, magnetic separation, and conveying is arranged in a closed series, directly connected to the vertical calcining furnace for discharge. There is no need for intermediate cooling and transfer links. The total temperature loss throughout the process is ≤50℃, which maximizes the preservation of the high-quality sensible heat of the material. It can be equipped with a subsequent waste heat recovery device to produce industrial steam. The waste heat recovered per ton of product is equivalent to about 15kg of standard coal, resulting in significant comprehensive energy-saving effects. At the same time, nitrogen protection is provided throughout the process to completely avoid oxidation and burn-off of high-temperature materials and air pollution. The sulfur and ash content of the product does not increase, ensuring the high-end quality of the calcined coke.

[0022] 3. This application adopts a synergistic process system of high-speed dispersing and deagglomeration, two-stage screening and grading, and two-stage gradient magnetic separation. First, it disperses and breaks up agglomerates, then it screens to remove extreme particle sizes, and finally, it removes metal impurities of different magnetic properties and particle sizes through coarse and fine separation. It has a high efficiency in removing various impurities such as iron, nickel, and copper embedded in calcined petroleum coke. The total metal impurities in the finished product can be stably reduced to below 20 ppm. It is suitable for the production of raw materials of different grades and products with different purity requirements, and has a wide range of applications.

[0023] 4. The circulating cooling temperature control unit is linked with the magnetic medium temperature in real time, resulting in good magnetic field stability; after expanding the online quality module, closed-loop control of impurity content can be achieved, resulting in excellent batch consistency of products; the cooling circuit is completely isolated from the material, eliminating the risk of leakage and pollution; the modular design of the magnetic medium components allows for quick disassembly and replacement, significantly reducing the overall operation and maintenance cost compared to hot magnetic separation without temperature control, making it suitable for large-scale industrial long-term continuous operation. Attached Figure Description

[0024] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0025] Figure 1 This is a schematic diagram of the overall structure of the present invention.

[0026] Figure 2 This is a schematic diagram of the structure of the primary hot vibrating screen of the present invention; Figure 3 This is a schematic diagram of the structure of the two-stage hot vibrating screen of the present invention; Figure 4 This is a schematic diagram of the structure of the first-stage coarsening high-gradient magnetic separator of the present invention; Figure 5 This is a schematic diagram of the internal structure of the primary coarsening high-gradient magnetic separator of the present invention; Figure 6 This is a schematic diagram of the material flow channel of the present invention; Figure 7 This is a schematic diagram of the feeding buffer and dispersing unit of the present invention.

[0027] In the diagram: 1. Sealed insulated outer shell; 2. Feed buffer and dispersing unit; 3. Primary hot vibrating screen; 4. Secondary hot vibrating screen; 5. Primary coarsening high-gradient magnetic separator; 6. Secondary cleaning high-gradient magnetic separator; 7. Sealed discharge conveying unit; 8. Circulating cooling temperature control unit; 9. Inert gas protection unit; 10. Insulated feed chute; 11. Conical buffer hopper; 12. High-speed dispersing roller; 13. Primary screen plate; 14. Secondary screen; 15. Ultrasonic screen cleaning device; 16. Magnetic yoke; 17. Excitation coil; 18. Magnetic medium assembly; 19. Magnetic medium filling layer; 20. Material flow channel; 21. Jacketed cooling chamber; 22. Cooling pipe; 23. Water inlet; 24. Water outlet; 25. Temperature sensor. Detailed Implementation

[0028] The present invention will now be described in further detail with reference to the accompanying drawings. These drawings are simplified schematic diagrams, illustrating only the basic structure of the invention, and therefore only show the components relevant to the invention.

[0029] Example 1: like Figures 1 to 6As shown, a multi-stage hot impurity removal device with magnetic medium temperature control for continuous production of calcined petroleum coke is provided in series along the material flow direction, consisting of a feeding buffer and dispersing unit 2, a two-stage hot vibrating screening unit, a two-stage temperature-controlled high-gradient magnetic separation unit, and a closed discharge conveying unit 7. The entire device is equipped with a sealed heat-insulating shell 1, and is connected to a circulating cooling temperature control unit 8 and an inert gas protection unit 9, forming a fully enclosed, continuous, temperature-controlled hot impurity removal system.

[0030] In this embodiment, the inner lining of the insulated feed chute 10 is a wear-resistant ceramic layer, and the outer wall is covered with an insulation layer. A high-temperature resistant sealing ring is installed at the flange connection, and the whole assembly is connected to the discharge port of the vertical continuous calcining furnace to achieve a leak-free and airtight connection. The conical buffer silo 11 has a conical structure that is wider at the top and narrower at the bottom, and its volume meets the material buffering capacity for 10 to 15 minutes. A level gauge is installed on the silo wall, which is linked with the upstream feed valve to control the material level height and avoid uneven material distribution caused by feed impact. The high-speed dispersing roller 12 is horizontally arranged at the outlet of the conical buffer silo 11. The roller surface is arranged with staggered arc-shaped dispersing teeth and driven by a variable frequency motor. It can completely disperse the soft agglomerates in the hot material, remove the coke powder from the metal impurities, and improve the efficiency of subsequent magnetic separation. The bearing seat of the high-speed dispersing roller 12 is equipped with an external water-cooling jacket to avoid high temperature conduction damage to the bearing and seals.

[0031] like Figure 1 As shown, the two-stage hot vibrating screening unit includes a primary linear vibrating screen and a secondary linear vibrating screen, both of which adopt a fully enclosed screen box structure. The outer wall of the screen box is covered with a heat insulation layer, and the interior is connected to the inert gas protection unit 9 throughout the entire process.

[0032] The primary linear vibrating screen is a coarse grading screen, also called primary screen plate 13. It adopts a high-temperature and wear-resistant perforated screen plate, which mainly removes large particle agglomerates and sintered lumps from the material. The material on the screen is discharged by a screw conveyor, crushed and returned to the calcination feeding system for reprocessing.

[0033] The secondary linear vibrating screen is a fine grading screen, also called a secondary screen 14. It adopts a precision woven screen and is equipped with an ultrasonic screen cleaning device 15 at the bottom of the screen plate. It works continuously to prevent fine coke powder from clogging the screen holes. It mainly removes ultrafine coke powder from the material. The ultrafine powder under the screen is collected in a closed system and processed separately.

[0034] Both vibrating screens use high-temperature resistant vibration damping components, and the screen box and the inlet and outlet chutes are sealed with soft connections to prevent vibration transmission and dust leakage.

[0035] like Figure 1 and Figure 5 As shown, in this embodiment, the two-stage temperature-controlled high-gradient magnetic separation unit is the core innovative part of the whole device, including a first-stage coarse high-gradient magnetic separator 5 and a second-stage fine high-gradient magnetic separator 6. The two magnetic separators have the same structure but different parameters, forming a gradient impurity removal system.

[0036] Each temperature-controlled high-gradient magnetic separator mainly consists of a magnetic yoke frame, excitation coil 17, magnetic medium assembly 18, material flow channel 20, cooling chamber, and temperature detection module. Among them, the magnetic yoke 16 is made of high magnetic permeability material to form a closed magnetic circuit; the excitation coil 17 is equipped with an independent water cooling circuit to maintain the coil operating temperature within a safe range.

[0037] In this embodiment, the magnetic medium component 18 is filled with multiple layers of magnetically conductive steel wool, which forms an extremely high magnetic field gradient under the action of a magnetic field, and can efficiently capture micron-sized weakly magnetic metal impurities.

[0038] In this embodiment, the core temperature control structure is as follows: a sealed annular jacketed cooling cavity 21 is provided around the magnetic medium component 18, and multiple sets of cooling tubes 22 are inserted inside the magnetic medium filling layer 19 along the material flow direction. The jacketed cooling cavity 21 is connected to the bottom and top of the internal cooling tubes 22, forming a dual reverse cooling circuit with the outer jacket covering the entire area and the inner tubes penetrating deep into the core. Cooling water enters from the bottom inlet 23, first cools the high-temperature area of ​​the magnetic medium core through the cooling tubes 22, then flows upward into the outer jacket, and finally exits from the top outlet 24. The heat exchange direction is the same as the material flow direction, resulting in more uniform cooling and higher efficiency.

[0039] Meanwhile, multiple temperature sensors 25 are installed inside the magnetic medium component 18 to monitor the temperature at different locations of the magnetic medium in real time and transmit the data to the circulating cooling temperature control unit 8; the material flow channel 20 is lined with wear-resistant and high-temperature resistant material, and the material flows from top to bottom through the magnetic medium filling area.

[0040] In this application, the parameter differences between the two stages of magnetic separation are set as follows: Primary roughing high gradient magnetic separator 5: background magnetic field strength 9000~13000Gs, material flow rate 0.6~1.0m / s, mainly removes large particles of strongly magnetic iron impurities, and protects the secondary fine high gradient magnetic separator.

[0041] Secondary high-gradient magnetic separator 6: background magnetic field strength 16000~22000Gs, material flow rate 0.3~0.6m / s, deeply removes fine-particle weak magnetic metal impurities such as nickel, cobalt, and copper, ensuring the purity of the final product.

[0042] The circulating cooling temperature control unit 8 includes an industrial chiller, a water distributor, a water collector, an electric flow regulating valve, a temperature control module, and a circulating pipeline, providing a constant temperature cooling water source for the magnetic separator and the bearing of the high-speed dispersing roller 12.

[0043] The industrial chiller unit's cooling capacity matches the heat load of two magnetic separators, ensuring a stable and controllable outlet water temperature. The chiller unit's outlet 24 connects to a distributor, branching off to the primary magnetic separation medium cooling, secondary magnetic separation medium cooling, primary magnetic separation coil cooling, and secondary magnetic separation coil cooling, respectively. Each pipeline is equipped with a flow regulating valve, flow meter, and temperature sensor 25. The temperature control module has a built-in control system that works in real-time with the temperature sensor 25 inside the magnetic medium, presetting the safe operating temperature range for the magnetic medium. When the magnetic medium temperature exceeds the upper threshold, the corresponding loop flow regulating valve automatically opens, increasing the cooling water flow. When the temperature falls below the lower threshold, the valve automatically closes, reducing cooling energy consumption and forming a precise closed-loop temperature control. The returned water after heat exchange flows into a collector and back to the chiller unit, forming a closed-loop circulation. The cooling water is completely isolated from the materials, eliminating the risk of contact contamination.

[0044] like Figure 1 As shown, the inert gas protection unit 9 includes a high-purity nitrogen source, a pressure reducing and stabilizing valve, multi-point gas distribution pipelines, an oxygen content detector, and an exhaust dust removal device. Nitrogen is introduced from multiple points, including the feed buffer silo, the primary screen box, the secondary screen box, and the feed inlets of the two magnetic separators, to ensure a uniform atmosphere inside the device. A slight positive pressure is maintained inside the device to prevent outside air from seeping in. The exhaust port is located at the top of the device, and dust is removed by the matching dust removal device before being uniformly discharged. An online oxygen content detector is installed at the discharge end to monitor the internal oxygen concentration in real time and control it at a low level to avoid oxidation and moisture absorption of the coke after high-temperature calcination, thus ensuring the stability of the carbon content and purity of the product.

[0045] like Figure 1 As shown, the closed discharge conveying unit 7 includes an insulated discharge chute and a closed conveying device; the discharge chute is lined with wear-resistant material and insulated on the outer wall, and is sealed to the concentrate port of the secondary high gradient magnetic separator 6; the conveying device is fully enclosed and conveys the high-temperature material after impurity removal to the subsequent vertical cooling waste heat recovery process, and the conveying distance can be flexibly adjusted according to the production line layout.

[0046] The device can be expanded with an online quality closed-loop module: an online metal composition detector is installed at the discharge chute to periodically detect the metal impurity content of the finished product, and the data is fed back to the magnetic separation control system; when the impurity content is too high, the magnetic field strength of the secondary magnetic separation is automatically increased and the material flow rate is reduced; when the impurity content is far below the standard, the magnetic field strength is automatically reduced and the flow rate is increased, realizing intelligent optimization of quality and energy consumption, and adapting to the upgrade needs of intelligent manufacturing production lines.

[0047] Example 2: This embodiment is the standard configuration for connecting to a 400,000-ton / year continuous production line of calcined petroleum coke. The specific structure and operating parameters are as follows: The device configuration includes a feeding buffer and dispersing unit 2, a primary 8mm vibrating screen, a secondary 0.075mm vibrating screen, a primary coarsening high-gradient magnetic separator 5, a secondary refining high-gradient magnetic separator 6, a circulating cooling temperature control unit 8, and an inert gas protection unit 9; the magnetic medium adopts a reverse dual cooling structure of "internal tube + external jacket", and four sets of PT100 temperature sensors 25 are arranged inside the magnetic medium.

[0048] Feed conditions: calcined petroleum coke discharged from the vertical calciner, temperature 420℃, total metal impurity content 125ppm (iron 85ppm, nickel 25ppm, copper 15ppm), particle size distribution 0.15~8mm, and processing capacity 50t / h.

[0049] Process parameters: High-speed dispersing roller 12 rotates at 450 r / min; The two-stage vibrating screen has a frequency of 20Hz and an amplitude of 3mm, with the secondary screen having an ultrasonic power of 500W. The primary magnetic separation field strength is 11000 Gs, the material flow rate is 0.8 m / s, and the magnetic media filling rate is 10%. The secondary magnetic separation field strength is 19000 Gs, the material flow rate is 0.45 m / s, and the magnetic media filling rate is 10%. Cooling system: chiller unit outlet water temperature 22℃, primary magnetic separation magnetic medium cooling water flow rate 18m³ / h, secondary magnetic separation 20m³ / h; Nitrogen protection: internal oxygen content 0.8%, slight positive pressure 70Pa.

[0050] Execution result: The magnetic medium has a stable operating temperature of 108℃, and the temperature uniformity within the layer has a deviation of ±4℃. The total metal impurities in the finished product were 18 ppm, with a total removal rate of 85.6%; including 10 ppm iron, 5 ppm nickel, and 3 ppm copper. The total temperature loss of the device is 42℃, and the discharge temperature is 378℃. After 30 days of continuous operation, the magnetic field attenuation rate was 0.3%, with no irreversible demagnetization. The material oxidation loss rate was 0.2%, with no significant decrease in carbon content.

[0051] Example 3: High-Temperature Feed Enhanced Impurity Removal Implementation Scheme This embodiment is designed for high-temperature calcination output and high-impurity raw materials, and enhances the cooling and impurity removal intensity. The specific parameters are as follows: Feed conditions: calcined petroleum coke from the high-temperature refining zone, temperature 480℃, total metal impurities 160ppm, raw material is high-sulfur and high-ash delayed petroleum coke, processing capacity 45t / h.

[0052] Process parameters: High-speed dispersing roller speed 550 r / min, to enhance dispersing and deagglomeration; The magnetic field strength of the primary magnetic separation is 12500 Gs, and the flow velocity is 0.7 m / s; The secondary magnetic separation field strength is 21000 Gs, and the flow velocity is 0.35 m / s; Cooling system: chiller unit outlet water temperature 20℃, primary magnetic separation cooling water flow rate 22m³ / h, secondary magnetic separation 25m³ / h; Nitrogen protection: Oxygen content 0.6%, increase nitrogen replenishment.

[0053] Execution result: The magnetic medium has a stable operating temperature of 115℃, which is within the safe threshold. The total metal impurities in the finished product were 15 ppm, with a total removal rate of 90.6%. The total temperature loss of the device is 45℃, the discharge temperature is 435℃, and the waste heat quality is high. After 30 days of continuous operation, the magnetic field attenuation rate was 0.4%, and the operation was stable.

[0054] Example 4: Energy-saving operation scheme for medium and low temperature feeding This embodiment is designed for medium-temperature discharge and low-impurity raw materials. Cooling parameters are optimized to reduce operating energy consumption. The specific parameters are as follows: Feed conditions: calcined petroleum coke from the medium-temperature calcination zone, temperature 320℃, total metal impurities 95ppm, raw material is imported low-sulfur coke, processing capacity 55t / h.

[0055] Process parameters: The high-speed dispersing roller rotates at 350 r / min; The magnetic field strength of the primary magnetic separation is 9500 Gs, and the flow velocity is 0.9 m / s; The secondary magnetic separation field strength is 17000 Gs, and the flow velocity is 0.55 m / s; Cooling system: chiller unit outlet water temperature 25℃, primary magnetic separation cooling water flow rate 12m³ / h, secondary magnetic separation 15m³ / h; Nitrogen protection: Oxygen content 1.0%.

[0056] Execution result: The magnetic medium has a stable operating temperature of 98℃. The total metal impurities in the finished product were 16 ppm, with a total removal rate of 83.2%, meeting the product standards. Cooling water energy consumption is reduced by 35% compared to Example 2, resulting in a significant decrease in operating costs; The total temperature loss of the device is 38℃, and the discharge temperature is 282℃.

[0057] Example 5: Intelligent Closed-Loop Control Upgrade Solution This embodiment adds an online XRF detection and intelligent control system to the basis of embodiment 2 to achieve intelligent manufacturing upgrade, as detailed below: New configuration: An online XRF metal analyzer is installed at the discharge end with a detection cycle of 10 seconds; the control system has a preset target total metal impurities of ≤20ppm, and adjusts the magnetic field strength and material flow rate in conjunction with the magnetic separation field strength.

[0058] Regulation logic: When the detected value is >18ppm, the magnetic field strength of the secondary magnetic separation increases by 5%, and the material flow rate decreases by 10%. When the detected value is <12ppm, the magnetic field strength of the secondary magnetic separation decreases by 5%, and the material flow rate increases by 10%. When the temperature of the magnetic medium exceeds 115℃, the cooling water flow rate will be automatically increased.

[0059] Execution result: After 7 days of continuous operation, the total metal impurities in the finished product fluctuated within the range of 16~19ppm, with a fluctuation range of ±1.5ppm, and the consistency was improved by 60% compared with manual control. The average consumption of cooling water and excitation energy is reduced by 12%, achieving a dynamic balance between energy saving and quality. It can operate unattended, reducing labor costs.

[0060] Example 6: Adaptation scheme for materials with high fine powder content This embodiment optimizes the screening and magnetic separation parameters for materials with a high proportion of fine powder and a tendency to clog screens, as follows: Feed conditions: calcined petroleum coke temperature 400℃, total metal impurities 130ppm, of which fine powder below 0.075mm accounts for 25%, and the processing capacity is 48t / h.

[0061] Process parameters: The ultrasonic cleaning power for secondary screening has been increased to 800W, with a vibration frequency of 22Hz and an amplitude of 2.5mm. The primary magnetic separation flow rate is 0.7 m / s, the secondary magnetic separation flow rate is 0.4 m / s, and the magnetic media filling rate is increased to 12%. The cooling parameters are the same as in Example 2.

[0062] Execution result: The screen operates continuously without clogging, ensuring stable screening efficiency. The total metal impurities in the finished product were 17 ppm, with a total removal rate of 86.9%. The ultrafine powder removal rate is over 95%, and there is no accumulation of fine powder in the magnetic separator.

[0063] Comparative Example 1: Traditional Cold Magnetic Separator A two-stage high-gradient magnetic separator of the same model was used. The material was cooled to 25°C by water before magnetic separation, and the magnetic field strength was exactly the same as in Example 2. Test results: The total metal impurities in the finished product were 52 ppm, with a total removal rate of 58.4%; all sensible heat of the material was dissipated, and there was no value in recovering residual heat; additional cooling and transfer processes were required, increasing the floor space by 40%.

[0064] Comparative Example 2: Hot Magnetic Separator without Temperature Control All magnetic medium cooling circuits were eliminated, and hot material at 420℃ was directly introduced. The remaining structure and parameters were the same as in Example 12. Test results: Initially, the total metal impurities in the finished product were 20 ppm, with a removal rate of 84%; after 7 days of continuous operation, the magnetic strength decreased by 18%, and the total metal impurities in the finished product increased to 42 ppm; after 30 days of continuous operation, the magnetic strength decreased by 45%, the magnetic medium underwent irreversible demagnetization, and the impurity removal ability was basically lost, resulting in equipment failure.

[0065] Comparative Example 3: A hot magnetic separator with only a water-cooled outer shell. This comparative example only has a water-cooled jacket on the outer shell of the magnetic separator, and there is no cooling pipe inside the magnetic medium. The other parameters are the same as in Example 2.

[0066] Test results: The surface temperature of the magnetic medium was 135℃, and the core temperature was 185℃. The temperature distribution was extremely uneven, with a deviation of 50℃. The total metal impurities in the finished product were 32ppm, with a total removal rate of 74.4%. After 30 days of continuous operation, the magnetic strength decreased by 12%, indicating poor magnetic field stability and large fluctuations in product indicators, which could not meet the consistency requirements of high-end products.

[0067] In summary, through the comparison of the above embodiments and comparative examples, the following conclusions can be clearly drawn: The impurity removal efficiency of the device of this invention is far superior to that of traditional cold magnetic separation, while fully preserving the sensible heat of the material, thus solving the inherent defects of low efficiency, high energy consumption and long process of cold process; This invention employs a reverse dual cooling structure with an inner tube and an outer jacket, which provides a cooling effect far superior to simple shell water cooling. It can stably control the temperature of the magnetic medium throughout the entire range within a safe threshold, exhibiting excellent temperature uniformity and no significant demagnetization during long-term operation. This completely solves the industry problem of short lifespan of hot magnetic separators. In contrast, Comparative Example 2 suffers from rapid failure due to lack of temperature control, and Comparative Example 3 shows insufficient cooling effect due to its simple cooling. This further proves that the temperature control structure of this invention is not a simple superposition of conventional techniques in the field. Those skilled in the art would not easily conceive of extending the cooling pipes deep into the core of the magnetic medium and adopting a reverse heat exchange design based on existing shell water cooling. This invention possesses outstanding substantive features. The multi-module system, which integrates dispersing, screening, magnetic separation, temperature control, and protection, works synergistically to achieve multiple technical benefits such as "high efficiency, long lifespan, low energy consumption, and high quality." The various structures support each other and work together to enhance efficiency. Dispersing improves magnetic separation efficiency, screening stabilizes magnetic separation conditions, temperature control ensures equipment lifespan, and protection maintains product quality.

[0068] Based on the above-described preferred embodiments of the present invention, and through the foregoing description, those skilled in the art can make various changes and modifications without departing from the inventive concept. The technical scope of this invention is not limited to the contents of the specification, but must be determined according to the scope of the claims.

Claims

1. A multi-stage hot impurity removal device with magnetic medium temperature control for continuous production of calcined petroleum coke, characterized in that, The following are connected in series along the material flow direction: Feed buffer and dispersing unit (2), two-stage hot vibrating screening unit, two-stage temperature-controlled high gradient magnetic separation unit and closed discharge conveying unit (7); The entire device is equipped with a sealed heat-insulating shell (1), and is equipped with an independent circulating cooling temperature control unit (8) and an inert gas protection unit (9); The two-stage temperature-controlled high-gradient magnetic separation unit consists of a first-stage coarse high-gradient magnetic separator (5) and a second-stage fine high-gradient magnetic separator (6) forming a gradient impurity removal system; Each of the magnetic separators is equipped with a magnetic media component (18) and a magnetic media filling layer (19). A sealed jacketed cooling chamber (21) is provided around the magnetic media component (18). Multiple sets of cooling pipes (22) are arranged inside the magnetic media filling layer (19). The jacketed cooling chamber (21) and the cooling pipes (22) are connected to form a dual cooling circuit. The circulating cooling temperature control unit (8) is connected to the dual cooling circuit and is used to perform forced cooling and temperature control on the magnetic medium component (18).

2. The hot-state multi-stage impurity removal device with magnetic medium temperature control for continuous production of calcined petroleum coke as described in claim 1, characterized in that, The feeding buffer and dispersing unit (2) includes an insulated feeding chute (10), a conical buffer hopper (11), and a high-speed dispersing roller (12); The inner lining of the insulated feed chute (10) is wear-resistant ceramic, and the outer wall is covered with an insulation layer. It is sealed and connected to the discharge port of the vertical continuous calcining furnace. The other end of the insulated feed chute (10) is connected to the conical buffer silo (11). The high-speed dispersing roller (12) is horizontally positioned at the outlet of the conical buffer hopper (11), with staggered dispersing teeth arranged on the roller surface. The rotation speed is 300~600 r / min. The high-speed dispersing roller (12) is provided with bearing seats at both ends and external water-cooling jackets.

3. The hot-state multi-stage impurity removal device with magnetic medium temperature control for continuous production of calcined petroleum coke as described in claim 1, characterized in that, The two-stage hot vibrating screen unit includes a primary hot vibrating screen (3) and a secondary hot vibrating screen (4); The screen aperture size of the primary hot vibrating screen (3) is 6~10mm, which is used to remove large particle agglomerates; The screen aperture size of the secondary hot vibrating screen (4) is 0.05~0.1mm, and the bottom of the screen plate is equipped with an ultrasonic screen cleaning device (15) for removing ultrafine coke powder; Both vibrating screens are fully enclosed and insulated, and the screen box and pipeline are sealed with high-temperature resistant flexible connections.

4. The hot-state multi-stage impurity removal device with magnetic medium temperature control for continuous production of calcined petroleum coke as described in claim 1, characterized in that, The cooling tubes (22) are inserted into the magnetic medium filling layer (19) with a spacing of 20~60mm. Cooling water enters the cooling tubes (22) from the bottom to exchange heat with the core area of ​​the magnetic medium, and then flows into the outer jacket cooling cavity (21) to flow upward and is discharged from the top, forming a dual cooling circuit with reverse heat exchange, so that the temperature deviation in the magnetic medium filling layer (19) is ≤±5℃.

5. The hot-state multi-stage impurity removal device with magnetic medium temperature control for continuous production of calcined petroleum coke as described in claim 1, characterized in that, The primary coarsening high-gradient magnetic separator has a background magnetic field strength of 9000~13000Gs and a material flow rate of 0.6~1.0m / s, and is used to remove large-particle strongly magnetic iron impurities; the secondary refining high-gradient magnetic separator has a background magnetic field strength of 16000~22000Gs and a material flow rate of 0.3~0.6m / s, and is used to deeply remove fine-particle weakly magnetic metal impurities.

6. The hot-state multi-stage impurity removal device with magnetic medium temperature control for continuous production of calcined petroleum coke as described in claim 1, characterized in that, The circulating cooling temperature control unit (8) includes an industrial chiller, a water distributor, a water collector, an electric flow regulating valve and a temperature control module; multiple temperature sensors (25) are arranged inside the magnetic medium component (18), and the temperature control module automatically adjusts the cooling water flow and inlet water temperature according to the real-time feedback of the temperature sensors (25), and controls the working temperature of the magnetic medium in a closed loop within the range of 100~120℃. The temperature sensor (25) is electrically connected to the circulating cooling temperature control unit (8).

7. The hot-state multi-stage impurity removal device with magnetic medium temperature control for continuous production of calcined petroleum coke as described in claim 1, characterized in that, The inert gas protection unit (9) is filled with high-purity nitrogen from multiple points including feeding, screening, and magnetic separation. The device maintains a slight positive pressure and controls the oxygen content to below 1% to prevent the high-temperature materials from oxidizing and burning.

8. The hot-state multi-stage impurity removal device with magnetic medium temperature control for continuous production of calcined petroleum coke as described in claim 1, characterized in that, The closed conveying unit (7) includes an insulated discharge chute and a closed conveying device. The discharge chute is sealed to the concentrate outlet of the secondary magnetic separator to realize the subsequent waste heat recovery process. The total temperature loss of the material throughout the entire process is ≤50℃.

9. The hot-state multi-stage impurity removal device with magnetic medium temperature control for continuous production of calcined petroleum coke as described in claim 1, characterized in that, The discharge end of the closed conveying unit (7) is equipped with an online metal detection unit to detect the metal impurity content of the finished product in real time. The data is fed back to the magnetic separation control system, which automatically adjusts the magnetic field strength and material flow rate to form a closed-loop control of product quality.

10. The hot-state multi-stage impurity removal device with magnetic medium temperature control for continuous production of calcined petroleum coke as described in claim 1, characterized in that, The total metal impurities in the finished product of this device are ≤20ppm, and the annual magnetic intensity attenuation rate of the magnetic medium is ≤2%.

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