Flue gas purification and recovery structure of a carbon material primary baking furnace

Abstract

The utility model belongs to graphite electrode processing technical field provides a flue gas purification recovery structure of carbon material primary baking furnace, its characterized in that, including the flue gas import unit, multistage purification unit, waste heat recovery unit and flue gas discharge unit that communicate in proper order, the flue gas import unit includes with the flue gas export of baking furnace connection's import flue duct and sets up on the flow control device of import flue duct, the multistage purification unit includes at least two stage purification device, is used for carrying out dust removal, desulfurization and filtration treatment to flue gas in proper order, the utility model primary dust removal chamber's cyclone separation and inertial sedimentation structure effectively removes large particle dust, the filler layer of secondary desulfurization reaction chamber and atomization spray system removes sulfide pertinently, the bag type filter assembly of fine filter chamber realizes flue gas fine filtration, and the high temperature, low temperature three -level heat exchanger of waste heat recovery unit carries out step -by -step recovery to flue gas heat, and through the special structure design of tube bundle strengthens heat transfer.

Description

Technical Field

[0001] This utility model belongs to the field of graphite electrode processing technology, and in particular relates to a flue gas purification and recovery structure for a primary roasting furnace for carbon materials. Background Technology

[0002] With the development of charcoal roasting technology, flue gas purification and waste heat recovery have become indispensable parts of the primary roasting furnace production process. However, existing flue gas purification and waste heat recovery technologies still have many shortcomings in practical applications. When dealing with the complex flue gas generated during charcoal roasting, it is difficult to simultaneously meet the requirements of efficient purification, heat recovery, and environmentally friendly emissions.

[0003] In existing technologies, flue gas purification and recovery devices generally suffer from discontinuous purification processes and insufficient purification levels, resulting in incomplete treatment of pollutants such as dust and sulfides in complex flue gases, making it difficult to consistently meet environmental emission standards. At the same time, waste heat recovery devices are mostly single-stage heat exchange designs, unable to achieve tiered heat recovery based on flue gas temperature gradients, resulting in low energy utilization. In addition, there is a lack of coordinated control mechanisms between the purification module and the waste heat recovery module, making it easy for fluctuations in flue gas parameters to affect the overall treatment effect and difficult to adapt to changes in the operating conditions of the roasting furnace.

[0004] Other technical solutions attempt to improve purification efficiency through complex structures, but they suffer from low system integration and independent operation of each functional unit, resulting in large equipment footprint, difficult installation and maintenance, and the lack of a complete process optimization design from flue gas introduction to emission, making it impossible to achieve efficient synergy between purification and waste heat recovery.

[0005] The aforementioned problems make it difficult for existing devices to balance purification effect, energy recovery, and operational economy in practical applications. There is an urgent need for an integrated and modular flue gas treatment structure that can solve the technical challenges of multi-stage purification, cascade heat exchange, and coordinated operation through systematic design.

[0006] Therefore, the technical problem to be solved by this utility model is to provide a structure for purifying and recovering flue gas from a primary roasting furnace of carbon materials that can overcome the above-mentioned shortcomings. Utility Model Content

[0007] To address the shortcomings of existing technologies, this utility model provides a flue gas purification and recovery structure for a primary calcination furnace for carbon materials, thus solving the problems mentioned in the background section.

[0008] The technical solution of this utility model is as follows:

[0009] A flue gas purification and recovery structure for a primary calcination furnace for carbon materials is characterized by comprising a flue gas inlet unit, a multi-stage purification unit, a waste heat recovery unit, and a flue gas emission unit connected in sequence.

[0010] The flue gas inlet unit includes a flue gas inlet pipe connected to the flue gas outlet of the roasting furnace and a flow control device installed on the flue gas inlet pipe.

[0011] The multi-stage purification unit includes at least two stages of purification devices for sequentially removing dust, desulfurizing and filtering flue gas.

[0012] The waste heat recovery unit includes at least one waste heat recovery device for multi-stage heat exchange of the purified flue gas to recover heat.

[0013] The flue gas emission unit is used to discharge the treated flue gas.

[0014] Furthermore, the multi-stage purification unit includes a primary dust removal chamber, a secondary desulfurization reaction chamber, and a fine filtration chamber connected in sequence; the primary dust removal chamber is connected to the flue gas inlet pipe through a first connecting pipe; the fine filtration chamber is connected to the waste heat recovery unit through a third connecting pipe.

[0015] Furthermore, the primary dust removal chamber is equipped with a cyclone separator and an inertial settling plate; the air inlet of the cyclone separator is connected to the first connecting pipe; the inertial settling plate is arranged at an inclination below the cyclone separator, and a first ash collection hopper is provided at its bottom.

[0016] Furthermore, the secondary desulfurization reaction chamber is filled with a desulfurizing agent layer, and an atomizing spray system is arranged above the desulfurizing agent layer; the atomizing spray system includes an annular water distribution pipe and multiple atomizing nozzles evenly distributed on the annular water distribution pipe; the annular water distribution pipe is connected to an external alkali supply device through a water supply pipeline.

[0017] Furthermore, the desulfurizing agent layer has a multi-layered packing structure, which includes a limestone particle layer, an activated alumina layer, and a zeolite molecular sieve layer from top to bottom; the annular water distribution pipe is horizontally fixed above the desulfurizing agent layer.

[0018] Furthermore, the fine filtration chamber is equipped with multiple sets of bag filter components; each set of bag filter components includes a filter bag frame and a composite filter bag fitted over the filter bag frame; the fine filtration chamber is equipped with a pulse cleaning system.

[0019] Furthermore, the waste heat recovery unit includes a high-temperature heat exchanger, a medium-temperature heat exchanger, and a low-temperature heat exchanger connected in sequence by pipes; the high-temperature heat exchanger is provided with a first heat exchange tube bundle, the medium-temperature heat exchanger is provided with a second heat exchange tube bundle, and the low-temperature heat exchanger is provided with a third heat exchange tube bundle; the first heat exchange tube bundle, the second heat exchange tube bundle, and the third heat exchange tube bundle are connected in series in sequence.

[0020] Furthermore, the high-temperature heat exchanger, the medium-temperature heat exchanger, and the low-temperature heat exchanger all adopt a shell-and-tube structure; the first heat exchange tube bundle adopts a spiral coil structure; the second heat exchange tube bundle adopts a straight tube bundle structure with enhanced heat transfer fins; and the third heat exchange tube bundle adopts a corrugated tube structure.

[0021] Furthermore, a star-shaped ash discharge valve is provided at the bottom of the first ash hopper; and each chamber of the multi-stage purification unit is provided with a drain outlet at the bottom.

[0022] Compared with the prior art, the beneficial effects of the technical solution provided by this utility model are as follows:

[0023] (1) The cyclone separation and inertial settling structure of the primary dust removal chamber effectively removes large particles of dust;

[0024] (2) The packing layer and atomizing spray system in the secondary desulfurization reaction chamber are used to remove sulfides; the bag filter assembly in the fine filter chamber achieves fine filtration of flue gas.

[0025] (3) The high-temperature, medium-temperature and low-temperature three-stage heat exchangers of the waste heat recovery unit recover the heat of the flue gas in stages, and enhance the heat transfer through the special structural design of the tube bundle. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the overall structure of this utility model;

[0027] In the diagram: 1. Smoke inlet duct; 2. Flow control device; 3. Primary dust removal chamber; 4. Cyclone separator; 5. Inertial settling plate; 6. First ash hopper; 7. Secondary desulfurization reaction chamber; 8. Desulfurizing agent layer; 81. Limestone particle layer; 82. Activated alumina layer; 83. Zeolite molecular sieve layer; 9. Annular water distribution pipe; 10. Atomizing nozzle; 11. Fine filtration chamber; 12. Filter bag frame; 13. Composite filter bag; 14. Compressed air storage tank; 15. Safety valve; 16. Branch pipe; 17. Pulse valve; 18. Pulse jet pipe; 19. Second ash hopper; 20. Waste heat recovery unit; 21. High-temperature heat exchanger; 22. First heat exchange tube bundle; 23. Medium-temperature heat exchanger; 24. Second heat exchange tube bundle; 25. Low-temperature heat exchanger; 26. Third heat exchange tube bundle; 29. ​​Ash discharge valve; 30. Drainage outlet. Detailed Implementation

[0028] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present utility model without creative effort are within the scope of protection of the present utility model.

[0029] See Figure 1 A flue gas purification and recovery structure for a primary roasting furnace for carbon materials includes a flue gas inlet unit, a multi-stage purification unit, a waste heat recovery unit 20, and a flue gas emission unit connected in sequence.

[0030] The flue gas introduction unit includes a flue gas inlet pipe 1 connected to the flue gas outlet of the roasting furnace and a flow control device 2 installed on the flue gas inlet pipe 1;

[0031] The flue gas inlet unit is located at the very front of the entire purification and recovery structure, and is responsible for guiding the high-temperature flue gas from the primary calcining furnace of the carbon material into the system. The flue gas inlet pipe 1 has a cylindrical structure. One end of the flue gas inlet pipe 1 is directly and fixedly connected to the flue gas outlet of the primary calcining furnace of the carbon material by welding, and the other end of the flue gas inlet pipe 1 is connected to the first connecting pipe of the primary dust removal chamber 3 of the multi-stage purification unit by flange connection. The flow control device 2 adopts an electric butterfly valve structure, and its diameter is the same as the inner diameter of the flue gas inlet pipe 1. The flow control device 2 is installed on the vertical section of the flue gas inlet pipe 1.

[0032] The multi-stage purification unit includes at least two stages of purification devices for sequentially removing dust, desulfurizing and filtering flue gas. By setting up a multi-stage purification unit, different purification mechanisms can be used to intercept dust and gaseous pollutants of different particle sizes in the flue gas, achieving efficient removal of pollutants.

[0033] The waste heat recovery unit 20 includes at least one stage of waste heat recovery device for multi-stage heat exchange of the purified flue gas to recover heat. By setting up the waste heat recovery unit 20, the heat difference of flue gas in different temperature ranges can be utilized to achieve cascade heat exchange through multi-stage heat exchangers, matching water systems with different temperature requirements, maximizing the recovery of heat energy in the flue gas, and reducing energy waste.

[0034] The flue gas emission unit is used to discharge the treated flue gas; the flue gas emission unit is located at the end of the entire purification and recovery structure and is responsible for discharging the treated clean flue gas into the atmosphere; the flue gas emission unit includes an induced draft fan and a flue gas exhaust stack, the induced draft fan is connected to the outlet of the waste heat recovery unit, the flue gas exhaust stack is arranged vertically and the bottom is connected to the exhaust port of the induced draft fan.

[0035] This utility model also integrates an advanced temperature monitoring and linkage control system to ensure the stability and efficiency of system operation. The temperature monitoring and linkage control system mainly includes a first temperature sensor located at the outlet of the fine filter chamber 11, a second temperature sensor located at the outlet of the high-temperature heat exchanger 21, a third temperature sensor located at the outlet of the medium-temperature heat exchanger 23, and a central controller. The first, second, and third temperature sensors all use armored K-type thermocouples, with the sensing element encapsulated in a stainless steel protective tube. The measurement accuracy is ±1 degree Celsius, and the response time is less than 5 seconds. Their respective signal output terminals are... The signal is connected to the analog input module of the central controller via a shielded cable. The central controller is a programmable logic controller with high-speed data acquisition, real-time processing, complex logic control and Ethernet communication functions. It is installed in an independent control cabinet with IP65 protection. In addition to receiving temperature data from three temperature sensors in real time, the central controller is also electrically connected to the servo motor driver of the flow control device 2 and the frequency converter of the induced draft fan through control lines. According to the preset control strategy (such as PID control algorithm), the opening degree of the flue gas flow control device 2 and the speed of the induced draft fan are precisely adjusted to optimize the system operating parameters.

[0036] like Figure 1 As shown, the multi-stage purification unit includes a primary dust removal chamber 3, a secondary desulfurization reaction chamber 7, and a fine filtration chamber 11 connected in sequence; the primary dust removal chamber 3 is connected to the flue gas inlet pipe 1 through a first connecting pipe; the fine filtration chamber 11 is connected to the waste heat recovery unit through a third connecting pipe.

[0037] The primary dust removal chamber 3 is equipped with a cyclone separator 4 and an inertial settling plate 5; the air inlet of the cyclone separator 4 is connected to the first connecting pipe; the inertial settling plate 5 is arranged at an inclination below the cyclone separator 4, and a first dust collection hopper 6 is provided at its bottom.

[0038] Specifically, the primary dust removal chamber 3 has a cylindrical shell structure with sufficient internal space to accommodate the cyclone separator 4 and the inertial settling plate 5. The shell side wall has an inspection door (not mentioned in the document but is a standard design for internal component maintenance). Flange interfaces are designed on the side and bottom for connecting the smoke inlet and outlet pipes and the first ash collection hopper 6, respectively.

[0039] The upper part of the cyclone separator 4 is a cylindrical shell, and the lower part is conical. Tangential air inlets are opened on the side walls to allow the flue gas to enter in a tangential direction and form a spiral upward airflow. An axial exhaust pipe is set at the top to discharge the flue gas after centrifugal separation. The lower part is a conical dust collection section. The conical surface design can guide the separated dust to collect at the bottom and avoid dust residue on the inner wall of the shell.

[0040] The tangential air inlet of the cyclone separator 4 is connected to the first connecting pipe through a flange to ensure that the flue gas can smoothly enter the separator in the tangential direction; the axial exhaust pipe extends upward, passes through the top of the primary dust removal chamber 3, and is connected to the second connecting pipe through a flange, so that the separated flue gas can directly enter the secondary desulfurization reaction chamber 7; the bottom opening of the conical ash collection section is connected to the upper opening of the first ash collection hopper 6 through a flange or welding to ensure that all the separated dust can fall into the first ash collection hopper 6; the bottom of the first ash collection hopper 6 is equipped with an ash discharge valve 29, which is connected to the external ash and slag conveying system to periodically discharge the collected dust;

[0041] When the flue gas enters the cyclone separator 4 tangentially, it generates high-speed rotational motion. The centrifugal force on the dust particles is much greater than that on the gas molecules. They are thrown against the inner wall of the cyclone separator 4 and settle along the wall surface. Meanwhile, the gas gathers towards the center during the rotation, forming an upward inner vortex, which is discharged from the axial exhaust pipe, thus achieving gas-solid separation.

[0042] The inertial settling plate 5 is inclinedly arranged below the cyclone separator 4, covering the space around and below the cyclone separator 4. It is fixed to the inner wall of the primary dust removal chamber 3 by welding brackets. The height and tilt angle of the brackets are adjustable to ensure that the airflow can flow evenly through each settling plate.

[0043] Multiple inertial settling plates 5 are arranged in an alternating manner, with the lower ends of the settling plates all facing the first ash hopper 6, so that the dust falling after the collision can slide directly into the first ash hopper 6; when the flue gas flows through the inertial settling plates 5, the airflow is forced to change its flow direction due to the obstruction of the settling plates; due to the large inertia of the dust particles, their trajectory is difficult to change quickly with the airflow, and they will collide with the settling plates and be captured, while the gas can smoothly bypass the settling plates and continue to flow, further realizing gas-solid separation;

[0044] The first dust hopper 6 has an overall inverted cone shape with an inclined wall. The angle of inclination is designed to ensure that the dust can slide down smoothly under gravity without accumulating. The bottom of the first dust hopper 6 has an opening for connecting to the subsequent dust discharge valve 29 to achieve centralized dust discharge.

[0045] Flue gas entry and preliminary separation: Flue gas from the calcining furnace enters the separator through the flue gas inlet pipe 1 and the first connecting pipe, and enters the separator through the tangential air inlet of the cyclone separator 4. Due to the inertia of tangential entry, the flue gas rotates at high speed along the inner wall of the cylindrical shell, forming a spiral upward airflow. During this process, larger and denser dust particles in the flue gas are thrown towards the inner wall of the shell under the action of centrifugal force, and then slide down the inner wall and enter the first ash collection hopper 6 through the conical ash collection section.

[0046] Secondary settling purification: After the flue gas has undergone preliminary dust removal by the cyclone separator 4, it is discharged from the axial exhaust pipe and flows downward into the area where the inertial settling plate 5 is located. Since the settling plates are arranged in an alternating manner, the flue gas needs to constantly change its flow direction to bypass the settling plates. During this process, the remaining fine dust particles in the flue gas cannot turn quickly with the airflow due to inertia. They will collide with the wavy surface of the settling plate and then slide down the settling plate under the action of gravity, falling into the first ash collection hopper 6 below.

[0047] Dust collection and discharge: The dust collected in the first dust collection hopper 6 is periodically discharged from the bottom opening of the first dust collection hopper 6 under the action of the ash discharge valve 29, so as to avoid the dust from accumulating and agglomerating in the hopper and ensure the continuous and stable operation of the primary dust removal chamber 3; the flue gas that has completed the secondary dust removal continues to flow upward and enters the secondary desulfurization reaction chamber 7 through the second connecting pipe for subsequent desulfurization treatment.

[0048] like Figure 1 As shown, the secondary desulfurization reaction chamber 7 is filled with a desulfurizing agent layer 8, and an atomizing spray system is arranged above the desulfurizing agent layer 8. The atomizing spray system includes an annular water distribution pipe 9 and multiple atomizing nozzles 10 evenly distributed on the annular water distribution pipe 9. The annular water distribution pipe 9 is horizontally fixed above the desulfurizing agent layer 8. The annular water distribution pipe 9 is connected to an external alkali supply device through a water supply pipeline. The desulfurizing agent layer 8 has a multi-layer packing structure, which includes a limestone particle layer 81, an activated alumina layer 82 and a zeolite molecular sieve layer 83 from top to bottom.

[0049] Specifically, the outlet end of the second connecting pipe is connected to the lower part of the secondary desulfurization reaction chamber 7, that is, the lower end of the desulfurizing agent layer 8; the secondary desulfurization reaction chamber 7 is designed as a vertical cylindrical structure, which allows the flue gas to form a stable upward airflow in the reaction chamber, avoiding insufficient desulfurization due to airflow turbulence; the top of the reaction chamber is provided with a flue gas outlet, and the bottom is provided with a drain outlet 30 (for discharging the waste liquid generated after spraying), and the side wall is reserved with an inspection port (for easy replacement of desulfurizing agent or maintenance of internal components in the future).

[0050] A grid support plate is installed at the lower end of the desulfurizing agent layer 8. The grid support plate has a porous plate structure with uniformly distributed pores, which allows the flue gas to diffuse evenly in the lateral direction, ensuring that each part of the flue gas can fully contact the packing. The support plate is made of corrosion-resistant stainless steel and has sufficient structural strength to support the weight of each layer of packing while ensuring that the flue gas can pass through the packing layer evenly. The grid support plate is fixed to the inner wall of the reaction chamber by welding or bolting. Each layer of packing is granular, and the particle size is matched to the pores of the support plate, which can ensure the smooth passage of flue gas and prevent the packing from leaking out from the gaps in the grid support plate.

[0051] The annular water distribution pipe 9 has a closed annular structure with uniformly reserved interfaces on the pipe body for installing atomizing nozzles 10; the atomizing nozzles 10 have a spiral or centrifugal atomizing structure, which can atomize the alkaline solution into fine droplets, increasing the contact area between the alkaline solution and the flue gas.

[0052] The annular water distribution pipe 9 is horizontally fixed above the desulfurizing agent layer 8 by a stainless steel bracket. The height of the bracket must ensure that the alkaline liquid droplets sprayed by the nozzle can just cover the entire surface of the desulfurizing agent layer 8, and that the droplets can fully mix with the rising flue gas during the falling process.

[0053] The liquid supply port of the annular water distribution pipe 9 is connected to an external alkaline solution supply device (such as an alkaline solution storage tank or a transfer pump 36) through a water supply pipeline. After being pressurized by the transfer pump, the alkaline solution enters the water distribution pipe and is then atomized and sprayed out through the atomizing nozzle 10. The nozzle sprays vertically downward, so that the alkaline solution droplets fall directly onto the surface of the uppermost limestone particle layer 81. Part of the alkaline solution reacts with the sulfides in the flue gas in the gas phase, and the other part penetrates into the packing layer and continuously reacts with the flue gas in the gaps between the packing layers, thereby improving the desulfurization efficiency.

[0054] The drain outlet 30 at the bottom of the reaction chamber is connected to the external wastewater treatment system through a pipe, which can discharge the waste liquid generated after spraying and reaction with the packing in a timely manner, and prevent the waste liquid from accumulating at the bottom of the reaction chamber and soaking the packing. An observation window 37 can be set on the side wall of the reaction chamber to facilitate the staff to observe the state of the desulfurizing agent layer 8 (such as whether it is clumped or needs to be replaced) and whether the spraying is uniform.

[0055] Flue gas enters: The flue gas that has had large particulate dust removed by the primary dust removal chamber 3 enters the secondary desulfurization reaction chamber 7 through the second connecting pipe. The flue gas flows slowly from bottom to top in the reaction chamber, passing through the zeolite molecular sieve layer 83, the activated alumina layer 82, and the limestone particle layer 81 in sequence.

[0056] Atomized spraying and preliminary reaction: The external alkaline solution supply device delivers alkaline solution to the annular water distribution pipe 9 through the water supply pipeline. The alkaline solution is atomized into fine droplets by the atomizing nozzle 10 and sprayed vertically downwards onto the surface of the limestone particle layer 81. The flue gas flowing from bottom to top and the falling alkaline solution droplets are in full contact above and inside the limestone particle layer 81. The sulfides (such as sulfur dioxide) in the flue gas undergo a neutralization reaction with the alkaline solution to generate solid or liquid desulfurization products.

[0057] Deep desulfurization of the packing layer: The unreacted flue gas continues to pass upward through the activated alumina layer 82. The porous structure of the activated alumina adsorbs the residual sulfides and small molecule impurities in the flue gas. Then the flue gas enters the zeolite molecular sieve layer 83. The specific pore structure of the molecular sieve further adsorbs water vapor and trace impurities in the flue gas, while intercepting unreacted alkaline droplets to prevent them from entering the subsequent fine filtration chamber with the flue gas.

[0058] Waste liquid discharge and flue gas transportation: The liquid products (including waste liquid containing desulfurization products) generated by the spray reaction flow downward along the gaps in the packing and collect at the bottom of the reaction chamber. They are then discharged into the wastewater treatment system through the drain outlet 30. The flue gas that has completed desulfurization and purification is discharged from the third connecting pipe at the top of the reaction chamber and enters the fine filter chamber 11 for the next step of fine filtration.

[0059] like Figure 1 As shown, the fine filtration chamber 11 is equipped with multiple sets of bag filter components; each set of bag filter components includes a filter bag frame 12 and a composite filter bag 13 sleeved on the outside of the filter bag frame 12; the fine filtration chamber 11 is equipped with a pulse cleaning system.

[0060] Specifically, the fine filtration chamber 11 has a rectangular box structure, which facilitates the neat matrix arrangement of multiple filter components; the top of the box is equipped with a flue gas outlet (connected to the waste heat recovery unit), the bottom is equipped with a conical second dust collection hopper 19 (to collect dust that falls off during cleaning), and the side wall is reserved with an inspection door (for easy filter bag replacement and internal maintenance).

[0061] The filter bag frame 12 includes a perforated plate symmetrically arranged on the upper and lower sides of the housing, longitudinal support wires, and transverse support rings. The perforated plate serves as a fixed carrier for the bag filter assembly. The perforated plate has circular mounting holes that match the number of filter bags to ensure precise positioning of the filter assembly. The longitudinal support wires are evenly distributed and fixedly connected between the upper and lower perforated plates along the circumference to ensure uniform circumferential force on the filter bags. The transverse support rings are spaced apart on the longitudinal support wires to prevent local depressions in the filter bags when flue gas flows, thus ensuring stable filtration area.

[0062] The composite filter bag 13 has a cylindrical bag structure with an elastic sealing ring at the top that fits tightly against the inner wall of the mounting hole in the upper tube sheet to prevent unfiltered flue gas from leaking through the installation gap (i.e., "short circuit"). The length of the filter bag matches the skeleton, and after being fitted, it can completely cover the surface of the skeleton without wrinkles or looseness, ensuring that the flue gas can only pass through the gaps between the filter bag fibers and thus achieve dust interception.

[0063] The pulse cleaning system includes a compressed air tank 14, a pulse valve 17, and a blowpipe 18. The compressed air tank 14 is installed at the upper end of the fine filter chamber 11. The compressed air tank 14 is equipped with a safety valve 15 and is connected to several branch pipes 16 in the fine filter chamber through a high-pressure air pipe. The lower end of the branch pipe 16 is equipped with a pulse valve 17, which is connected to the blowpipe 18. The blowpipe 18 is located directly above the filter bag frame 12 and maintains a fixed distance from the filter bag (to ensure that the blown airflow can fully act on the filter bag).

[0064] Each blowpipe 18 corresponds to a row of filter bags, and the blow holes are precisely aligned with the center of each filter bag frame 12. The central controller is electrically connected to the pulse valve 17 and can control the pulse valve 17 to open sequentially according to a preset cycle. When a single row of pulse valves 17 is opened, compressed air is injected at high speed into the corresponding filter bag through the blow holes of the blowpipe 18. After completing the cleaning of a single row, the valve is closed, and then the next row is opened to achieve "cleaning row by row" and avoid the flue gas outlet concentration from rising instantaneously due to overall cleaning.

[0065] The bottom of the second ash hopper 19 at the bottom of the fine filtration chamber is equipped with an ash discharge valve 29, which is connected to the external ash and slag conveying system to periodically discharge the collected dust;

[0066] The flue gas after secondary desulfurization enters from the bottom inlet of the fine filter chamber 11 and is evenly diffused between multiple sets of bag filter components under the action of airflow. The flue gas passes through the fiber gaps of the composite filter bag 13 from the outside of the filter bag. During the process, dust particles (including desulfurization product particles, residual dust, etc.) are intercepted by the filter bag membrane layer and adhere to the outer surface of the filter bag. The clean flue gas after dust removal enters the inside of the filter bag, flows upward along the filter bag skeleton 12, is collected in the gas collection chamber above the upper tube sheet, and is discharged from the top outlet of the fine filter chamber and enters the waste heat recovery unit.

[0067] Pulse cleaning of filter bags: As filtration time increases, the dust layer on the outer surface of the filter bag gradually thickens, and the pressure difference (filtration resistance) between the inside and outside of the filter bag increases accordingly; when the resistance reaches a preset value (or according to a preset cycle), the central controller sends a command to the pulse cleaning system:

[0068] First, the pulse valve 17 corresponding to the row of filter bags is opened. The high-pressure air in the compressed air tank 14 is injected into the filter bag frame 12 in the form of a high-speed airflow jet through the pulse valve 17 and the blow hole of the blow pipe 18.

[0069] High-speed airflow causes the filter bag to expand and vibrate instantly, while generating a "reverse airflow" that peels off the dust layer attached to the outer surface of the filter bag.

[0070] The detached dust falls under gravity and enters the second ash collection hopper 19 at the bottom of the fine filter chamber, and is then discharged through the ash discharge valve 29. After the cleaning of a single row of filter bags is completed, the pulse valve 17 of that row closes, and the pulse valve 17 of the next row opens in sequence, repeating the above process until all filter bags are cleaned. During the cleaning process, other rows of filter bags filter normally, without affecting the overall continuity of flue gas treatment of the system.

[0071] like Figure 1As shown, the waste heat recovery unit 20 includes a high-temperature heat exchanger 21, a medium-temperature heat exchanger 23, and a low-temperature heat exchanger 25 connected in sequence by pipes; the high-temperature heat exchanger 21 is provided with a first heat exchange tube bundle 22, the medium-temperature heat exchanger 23 is provided with a second heat exchange tube bundle 24, and the low-temperature heat exchanger 25 is provided with a third heat exchange tube bundle 26; the first heat exchange tube bundle 22, the second heat exchange tube bundle 24, and the third heat exchange tube bundle 26 are connected in series.

[0072] The high-temperature heat exchanger 21, the medium-temperature heat exchanger 23, and the low-temperature heat exchanger 25 all adopt a shell-and-tube structure; the first heat exchange tube bundle 22 adopts a spiral coil structure; the second heat exchange tube bundle 24 adopts a straight tube bundle structure with reinforced heat transfer fins; and the third heat exchange tube bundle 26 adopts a corrugated tube structure.

[0073] Specifically, the first heat exchange tube bundle 22 adopts a spiral coil structure and is fixed to both ends of the heat exchanger by a tube sheet; the second heat exchange tube bundle 24 adopts a straight tube bundle structure with reinforced heat transfer fins, which are evenly arranged along the circumference of the tube sheet, and rectangular fins are vertically welded to the outside of the straight tubes, with the fins evenly distributed along the tube length; the third heat exchange tube bundle 26 (inside the low-temperature heat exchanger) adopts a corrugated tube structure: the tube bundle is a corrugated tube and is fixed to both ends of the heat exchanger by a tube sheet.

[0074] Each heat exchange tube bundle is connected in series by pipes, and the inlet and outlet of the tube bundle are connected by flanges to ensure no leakage of the medium. The flow direction of the medium is counter-current to the flow direction of the flue gas (e.g., flue gas from left to right, medium from right to left). Counter-current can maintain a large temperature difference in each section of the tube bundle, significantly improving the overall heat exchange efficiency.

[0075] The outlet of the first heat exchange tube bundle 22 is connected to the external high-temperature water system, and the inlet of the third heat exchange tube bundle 26 is connected to the external low-temperature water system, so as to realize the cascade utilization of heat absorption by the low-temperature medium to energy supply by the high-temperature medium and avoid energy waste.

[0076] External low-temperature water (such as cold water) → inlet of the third heat exchange tube bundle 26 (absorbs heat from low-temperature flue gas, initially raising the temperature) → outlet of the third heat exchange tube bundle 26 → inlet of the second heat exchange tube bundle 24 (absorbs heat from medium-temperature flue gas, raising the temperature a second time) → outlet of the second heat exchange tube bundle 24 → inlet of the first heat exchange tube bundle 22 (absorbs heat from high-temperature flue gas, raising the temperature a third time) → outlet of the first heat exchange tube bundle 22 → high-temperature water is supplied to external systems (such as boiler feedwater, hot water for production).

[0077] The above description is only a preferred embodiment of the present utility model, but the protection scope of the present utility model is not limited thereto. Any equivalent substitutions or changes made by those skilled in the art within the technical scope disclosed in the present utility model, based on the technical solution and concept of the present utility model, should be included within the protection scope of the present utility model.

Claims

1. A flue gas purification and recovery structure for a primary roasting furnace of carbon materials, characterized in that, It includes a flue gas inlet unit, a multi-stage purification unit, a waste heat recovery unit (20) and a flue gas emission unit connected in sequence; The flue gas inlet unit includes a flue gas inlet pipe (1) connected to the flue gas outlet of the roasting furnace and a flow control device installed on the flue gas inlet pipe (1); The multi-stage purification unit includes at least two stages of purification devices for sequentially removing dust, desulfurizing and filtering flue gas. The waste heat recovery unit (20) includes at least one stage of waste heat recovery device for multi-stage heat exchange of the purified flue gas to recover heat. The flue gas emission unit is used to discharge the treated flue gas.

2. The flue gas purification and recovery structure of the primary roasting furnace for carbon materials according to claim 1, characterized in that, The multi-stage purification unit includes a primary dust removal chamber (3), a secondary desulfurization reaction chamber (7), and a fine filtration chamber (11) connected in sequence; the primary dust removal chamber (3) is connected to the flue gas inlet pipe (1) through a first connecting pipe; the fine filtration chamber (11) is connected to the waste heat recovery unit through a third connecting pipe.

3. The flue gas purification and recovery structure of the primary roasting furnace for carbon materials according to claim 2, characterized in that, The primary dust removal chamber (3) is equipped with a cyclone separator (4) and an inertial settling plate (5); the air inlet of the cyclone separator (4) is connected to the first connecting pipe; the inertial settling plate (5) is arranged at an angle below the cyclone separator (4), and a first dust collection hopper (6) is provided at its bottom.

4. The flue gas purification and recovery structure of the primary roasting furnace for carbon materials according to claim 2, characterized in that, The secondary desulfurization reaction chamber (7) is filled with a desulfurizing agent layer (8), and an atomizing spray system is arranged above the desulfurizing agent layer (8); the atomizing spray system includes an annular water distribution pipe (9) and multiple atomizing nozzles (10) evenly distributed on the annular water distribution pipe (9); the annular water distribution pipe (9) is connected to an external alkali supply device through a water supply pipeline.

5. The flue gas purification and recovery structure of the primary roasting furnace for carbon materials according to claim 4, characterized in that, The desulfurizing agent layer (8) is a multi-layered filler structure, which includes a limestone particle layer (81), an active alumina layer (82) and a zeolite molecular sieve layer (83) from top to bottom; the annular water distribution pipe (9) is horizontally fixed above the desulfurizing agent layer (8).

6. The flue gas purification and recovery structure of the primary roasting furnace for carbon materials according to claim 2, characterized in that, The fine filtration chamber (11) is equipped with multiple sets of bag filter components; each set of bag filter components includes a filter bag frame (12) and a composite filter bag (13) sleeved on the outside of the filter bag frame (12); the fine filtration chamber (11) is equipped with a pulse cleaning system.

7. The flue gas purification and recovery structure of the primary roasting furnace for carbon materials according to claim 1, characterized in that, The waste heat recovery unit (20) includes a high-temperature heat exchanger (21), a medium-temperature heat exchanger (23), and a low-temperature heat exchanger (25) connected in sequence by pipes; the high-temperature heat exchanger (21) is provided with a first heat exchange tube bundle (22), the medium-temperature heat exchanger (23) is provided with a second heat exchange tube bundle (24), and the low-temperature heat exchanger (25) is provided with a third heat exchange tube bundle (26); the first heat exchange tube bundle (22), the second heat exchange tube bundle (24), and the third heat exchange tube bundle (26) are connected in series.

8. The flue gas purification and recovery structure of the primary roasting furnace for carbon materials according to claim 7, characterized in that, The high-temperature heat exchanger (21), the medium-temperature heat exchanger (23), and the low-temperature heat exchanger (25) all adopt a shell-and-tube structure; the first heat exchange tube bundle (22) adopts a spiral coil structure; the second heat exchange tube bundle (24) adopts a straight tube bundle structure with reinforced heat transfer fins; and the third heat exchange tube bundle (26) adopts a corrugated tube structure.

9. The flue gas purification and recovery structure of the primary roasting furnace for carbon materials according to claim 3, characterized in that, The bottom of the first ash hopper (6) is provided with a star-shaped ash discharge valve (29); each chamber of the multi-stage purification unit is provided with a drain outlet (30) at its bottom.

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