Kaolin gas calcining shaft kiln

Abstract

The invention provides a kaolin gas calcining shaft kiln, belongs to the technical field of kaolin calcining, and aims to solve the problems that a product of traditional kaolin calcining equipment is easy to generate black / blue cores, the environmental protection is not up to standard, the energy consumption is high and the automation degree is low. The shaft kiln comprises a kiln body with the height of meter, a kiln top distributing device arranged at the top of the kiln body, a multi-layer composite refractory material layer built on the inner wall of the kiln body, a supporting plate discharging machine installed on the lower portion of the kiln body, a canopy covering the upper portion of the kiln body, a feeding system, a control system, burners and combustion fans, wherein the burners and the combustion fans are arranged on the side portions of the kiln body. The combustion-supporting pipeline is connected with the combustion-supporting fan and the burner, the air cap is arranged at the inner bottom of the kiln body, the cooling fan is arranged at the lower part of the kiln body, and the funnel weighing discharge port is connected with the feeding system. Through uniform material distribution, accurate temperature control and automatic control, the kaolin calcining qualified rate is increased, the fuel gas consumption is reduced, flue gas emission meets the national standard, meanwhile, the labor cost is reduced, and the kaolin calcining device is suitable for industrial efficient calcining operation.

Description

Technical Field

[0001] This invention belongs to the field of kaolin calcination technology, and more specifically, relates to a gas-fired vertical kiln for calcining kaolin. Background Technology

[0002] Kaolin is a key raw material in industries such as ceramics, papermaking, and coatings. Its calcination quality directly determines the performance of downstream products. Currently, the kaolin calcination equipment widely used in the industry is mostly traditional coal-fired vertical kilns or simple gas-fired vertical kilns. In practical applications, these kilns present numerous technical challenges, making it difficult to meet the production demands for high quality, low energy consumption, and environmental friendliness. Specific problems are as follows:

[0003] Unstable product quality and susceptibility to defects: Traditional vertical kilns often use a fixed material feeding structure at the kiln top, resulting in uneven distribution of raw materials within the kiln body. This easily leads to a "furnace wall effect" (thin material layer near the furnace wall and thick material layer in the center), causing localized insufficient or overheating. As a result, calcined kaolin often exhibits black core (incomplete internal calcination) and blue core (localized reduction reaction), with a product qualification rate of only about 85%. Whiteness is difficult to maintain above 80%, failing to meet the requirements for whiteness and purity of kaolin in high-end refractory materials, casting materials, ceramics, and papermaking.

[0004] Poor environmental performance and non-compliance with emission standards: Some traditional equipment uses coal-fired heating, which generates a large amount of particulate matter, SO2 and other pollutants during combustion, and lacks effective flue gas treatment design; even simple gas-fired vertical kilns rely on manual adjustment of the ratio of combustion fan 16 and burner 9, resulting in incomplete combustion of gas and excessive concentrations of CO and NOx in flue gas, making it difficult to meet the requirements of particulate matter ≤10mg / m³ and SO2 ≤35mg / m³ in the industrial furnace air pollutant emission standards, and facing the risk of environmental rectification or production shutdown.

[0005] High energy consumption and high production costs: Traditional vertical kilns often use a single-layer refractory brick structure for the kiln body, resulting in a heat loss rate of over 25%. At the same time, the feeding system relies on manual cart transportation and weighbridge weighing, which is not only inefficient (the feeding time for a single batch exceeds 30 minutes), but also prone to fluctuations in the thickness of the material layer inside the kiln due to raw material measurement errors, further increasing gas consumption—the gas consumption per ton of kaolin raw material can reach 80m³, far exceeding the industry's energy-saving indicators. In addition, manual operation requires 5-6 people per shift, and labor costs account for more than 15% of the production cost.

[0006] The low level of automation and reliance on experience in operation mean that key parameters such as calcination temperature, furnace pressure, and cooling wind speed of traditional equipment all require manual inspection and adjustment, lacking real-time monitoring and automatic feedback mechanisms. When the temperature inside the kiln rises or falls suddenly, the lag in manual adjustment can easily lead to over-sintering or under-sintering of the raw materials. The discharge frequency of the pallet discharge machine depends on manual judgment, which can easily lead to "material blockage" or "empty kiln" phenomena, affecting the continuity of production and making it difficult to meet the needs of large-scale and standardized kaolin production. Summary of the Invention

[0007] To address the aforementioned technical problems, this invention provides a gas-fired vertical kiln for calcining kaolin, which solves the technical problems of traditional kaolin calcining equipment, such as products easily developing black / blue cores, failing to meet environmental emission standards, high energy consumption, and low automation, making it difficult to meet the demands of high-quality, low-consumption, and environmentally friendly industrial production.

[0008] A kaolin gas-fired vertical kiln includes a kiln body with a height of meters, a kiln top material distribution device at the top of the kiln body, a refractory material layer built into the inner wall of the kiln body, a pallet discharge machine installed at the bottom of the kiln body, a canopy covering the top of the kiln body, a feeding system for conveying raw materials to the kiln body, a control system for controlling the operation of the kiln, burners and combustion fans arranged on the side of the kiln body, combustion pipes connecting the combustion fans and burners, an air cap at the bottom of the kiln body, a cooling fan installed at the bottom of the kiln body, and a hopper weighing discharge port connected to the feeding system.

[0009] The feeding system includes a traveling mine car, a plate puller that works with the traveling mine car, a transition hopper located downstream of the plate puller, a feeding car connected to the transition hopper, a mine car weighing and loading kiln that receives the material discharged from the feeding car, a feeding inclined bridge that connects the mine car weighing and loading kiln, a winch that drives the feeding inclined bridge, a raw material hopper located below the feeding inclined bridge, a vibrating feeder connected to the raw material hopper, a vibrating screen that works with the vibrating feeder, and a fine material conveyor belt that receives the material under the vibrating screen.

[0010] The control system includes a control room and PLC and DSC control modules located inside the control room;

[0011] The pallet discharge machine, combustion fan, vibrating feeder, and winch are all electrically connected to the PLC and DSC control modules.

[0012] Preferably, the kiln body adopts an improved steel structure, which includes annular reinforcing ribs spaced apart along the height of the kiln body, and the steel structure is fixedly connected to the kiln body foundation by pre-embedded bolts, so as to reduce the amount of steel used and reduce manufacturing costs.

[0013] Preferably, the refractory material layer is a multi-layer composite energy-saving structure, consisting of a high-alumina refractory brick layer, a lightweight insulating brick layer, and a refractory castable layer from the inside to the outside of the kiln body, in order to improve the heat insulation performance of the kiln body and reduce heat loss. The kiln top material distribution device is a four-point material distribution device and a disc material distribution device, which achieves uniform material distribution of raw materials.

[0014] Preferably, the pallet discharge machine is equipped with a hydraulic tie rod drive mechanism, which includes a hydraulic pump, a hydraulic cylinder connected to the hydraulic pump, and a tie rod connected at one end to the piston rod of the hydraulic cylinder and at the other end to the pallet of the pallet discharge machine. The pallet is moved back and forth smoothly by hydraulic drive to improve the stability of the equipment. The traveling mine car travels along a preset track, and the discharge end of the traveling mine car is set to correspond to the feed end of the transition funnel. The discharge end of the transition funnel is connected to the feed port of the loading car through a chute. The loading car is transported to the feed end of the mine car weighing and loading into the kiln through the track, realizing the continuous operation of raw materials from transportation to weighing.

[0015] Preferably, the PLC and DSC control modules have functions for adjusting combustion parameters, real-time detection of raw material weight, and automated control of the production process. They can adjust the gas supply of the burners, the air volume of the combustion fan, and the air speed of the cooling fan in real time according to the temperature and pressure signals inside the kiln. The combustion fan is installed in the lower middle part of the kiln body, and the air outlet of the combustion fan is connected to the air inlet of the burners through the combustion pipe. The combustion pipe is equipped with a flow regulating valve, which is electrically connected to the PLC and DSC control modules and can automatically adjust the combustion air flow.

[0016] Preferably, the air caps are in multiple sets and evenly distributed on the bottom support grate plate of the kiln body. The air inlet end of the air cap is connected to the air outlet pipe of the cooling fan. Cooling air is delivered to the lower part of the kiln body through the air caps to achieve uniform cooling of the material after calcination. The rain canopy is an arc-shaped steel structure canopy that covers the top of the kiln body and the control room. The edge of the rain canopy extends to the side of the kiln body above the burners to block rainwater and protect the kiln top material distribution device and burners. A weight sensor is installed in the weighing outlet of the funnel. The weight sensor is electrically connected to the PLC and DSC control modules and can detect the weight of the discharged material in real time and feed it back to the control system.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] Product quality has been significantly improved and stability enhanced. Through the four-point material distribution system at the top of the kiln and the disc material distributor, the raw material can evenly cover more than 90% of the kiln chamber cross-section, effectively eliminating the furnace wall effect. With the real-time control of the burner gas supply and combustion fan air volume by the PLC and DSC control modules, as well as the uniform cooling of the air cap, the temperature field and airflow field during the calcination of kaolin are more stable, the black core and blue core phenomena are completely eliminated, the product qualification rate is improved, and the whiteness is stable, meeting the raw material requirements of industries such as refractory materials, casting materials, high-end ceramics, and papermaking.

[0019] Environmentally compliant and in compliance with policy requirements, this invention adopts an environmentally friendly design combining gas combustion, a slightly negative pressure furnace, and coordinated temperature control. The electric flow regulating valve on the combustion-supporting pipeline is linked to a PLC module to ensure a stable gas-to-combustion air ratio of 1:10 (optimal combustion ratio), improving gas combustion efficiency and reducing CO2 emissions. Simultaneously, the furnace pressure is controlled at a slightly negative pressure of -50 to -100 Pa to prevent flue gas leakage. Combined with subsequent desulfurization and dust removal systems, this ensures that flue gas pollutant emission concentrations meet standards, solving the problem of environmental compliance for enterprises and reducing environmental remediation costs.

[0020] Energy consumption is significantly reduced, and production costs are optimized. The multi-layer composite refractory material layer on the inner wall of the kiln reduces the heat loss rate from 25% to below 10%, improving thermal efficiency. The automated feeding system integrates raw material conveying, weighing, and kiln feeding, shortening the feeding time per batch and controlling the metering accuracy within 5%, avoiding energy waste caused by material layer fluctuations. Ultimately, the gas consumption per ton of kaolin raw material is reduced from 80m³ to 50m³, resulting in reduced energy consumption and savings in gas costs.

[0021] With a high degree of automation and reduced operational difficulty, the control system achieves full-process automation: the feeding system can automatically complete the transportation, weighing, and screening of raw materials; during the calcination process, temperature and pressure sensors provide real-time data feedback, and the module automatically adjusts the parameters of the burner, combustion fan, and cooling fan; in the discharge stage, the weight sensor at the hopper weighing outlet automatically controls the frequency of the pallet discharge machine without manual intervention.

[0022] The equipment is highly durable and has low maintenance costs. The kiln body adopts an improved steel structure, which is fixed to the foundation through embedded parts, thereby improving structural strength and extending service life. The canopy covers the top of the kiln body, the control room, and the burner, which can effectively block rainwater and dust and reduce component corrosion and damage. In addition, the core components are designed to be easy to disassemble and replace, and the daily maintenance cycle is extended to 8 hours / time, reducing maintenance costs. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the overall structure of the present invention;

[0024] Figure 2 This is a side view of the present invention;

[0025] Figure 3 This is a top view of the present invention.

[0026] Figure 4 This is a schematic diagram of the kiln body steel structure of the present invention.

[0027] In the diagram, the correspondence between the component names and the attached drawing numbers is as follows: 1. Control room; 2. Canopy; 3. Pallet discharge machine; 4. Plate puller; 5. Traveling mine car; 6. Transition funnel; 7. Feeding car; 8. Mine car weighing and loading kiln; 9. Burner; 10. Feeding inclined bridge; 11. Winch; 12. Raw material funnel; 13. Vibrating feeder; 14. Fine material belt conveyor; 15. Vibrating screen; 16. Combustion fan; 17. Funnel weighing and discharging port; 18. Combustion pipeline; 19. Air cap; 20. Cooling fan; 21. Kiln body. Detailed Implementation

[0028] The embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. The following examples are for illustrative purposes only and should not be construed as limiting the scope of the invention.

[0029] Please see Figures 1-4 This invention provides a gas-fired vertical kiln for calcining kaolin. The disclosed gas-fired vertical kiln for calcining kaolin aims to solve the technical problems of traditional kaolin calcining equipment, such as the tendency for products to have a black / blue core, failure to meet environmental standards, high energy consumption, and low automation. Through optimized design of the kiln structure, feeding system, combustion control system, and cooling system, it achieves efficient, stable, and low-consumption industrial calcination of kaolin. The following detailed description of the specific implementation process, structural function, and control logic of this invention, based on the core structure and functions specified in the document, provides a detailed explanation.

[0030] Before starting a gas-fired vertical kiln for calcining kaolin, it is necessary to complete equipment status verification and raw material pretreatment to ensure that the entire system meets the conditions for continuous and stable operation. The specific operations are as follows:

[0031] A comprehensive equipment status check was conducted using the PLC and DSC control modules in control room 1 to perform power-on and mechanical performance tests on each core component.

[0032] Inspect the hydraulic pull rod drive mechanism (including hydraulic pump, hydraulic cylinder, and pull rod) of pallet discharge machine 3 to confirm that there is no hydraulic oil leakage, the pull rod extends and retracts smoothly, and the pallet fits the guide rail without jamming.

[0033] Start the combustion fan 16 and cooling fan 20, listen for any abnormal noise from the motors, and check the flange connections of the combustion pipe 18 with soapy water to check for any gas / combustion air leaks.

[0034] Calibrate the weight sensor inside the weighing outlet 17 of the funnel to ensure that the data is zero and avoid subsequent discharge measurement errors;

[0035] Inspect the refractory material layer on the inner wall of kiln body 21 (from the inside out, it consists of a first-grade high-alumina mullite layer, a lightweight insulating brick layer, and a refractory castable layer), and confirm that there is no peeling or cracking. If there is local damage, repair it with the same type of refractory castable until it is smooth.

[0036] Raw material pretreatment and storage: The coal gangue and kaolin raw materials to be calcined are crushed to a particle size of 15-20mm (to avoid uneven calcination and incomplete internal burning due to excessive particle size) and temporarily stored in the raw material warehouse; at the same time, the screen mesh size of the vibrating screen 15 is checked to ensure that the screen mesh is undamaged and the tension is appropriate; the conveyor belt of the fine material belt 14 is checked to confirm that there are no deviation or tearing problems, and the surface of the conveyor belt is cleaned to avoid residual impurities contaminating the raw materials.

[0037] The feeding system achieves fully automated flow of raw materials from transportation, weighing, screening to kiln entry through the collaboration of multiple devices. The specific steps are as follows:

[0038] The initial transportation and unloading of raw materials begins with the starting of the traveling mine car 5. The traveling mine car 5 picks up materials from the raw material bin along the preset track and travels to the loading point.

[0039] Next to trigger 4; when trigger 4 is started, it pushes the unloading gate of the traveling mine car 5 through the hydraulic push rod, unloading the raw material into the transition funnel 6; the outlet of the transition funnel 6 is equipped with an electric gate valve, which is controlled by the PLC module according to the arrival signal of the loading car 7. The raw material slowly falls into the loading car 7 through the chute at the bottom of the transition funnel 6 (the inner wall of the chute is lined with wear-resistant ceramic to reduce the wear of the raw material on the chute), avoiding the overflow of raw material.

[0040] The raw material weighing and lifting loading car 7 travels along the track to the bottom of the mine car weighing loading kiln 8. The weight detection module of the mine car weighing loading kiln 8 is activated to collect the weight of the raw material after unloading from the loading car 7 in real time. If the weight meets the preset batch quantity, the discharge door of the mine car weighing loading kiln 8 is automatically opened, and the raw material falls into the feed hopper of the loading inclined bridge 10. The winch 11 is started, and the winch 11 drives the hopper of the loading inclined bridge 10 to rise along the inclined bridge track (inclination angle of 74°, the track surface is coated with wear-resistant coating) through the steel wire rope (using anti-corrosion galvanized material) until the hopper reaches the feeding position at the top of the kiln body 21, completing the raw material lifting.

[0041] After the hopper of the inclined bridge 10 for raw material screening and kiln feeding reaches the designated position, the raw material is unloaded into the raw material funnel 12 through the unloading mechanism. The discharge end of the raw material funnel 12 is connected to the vibrating feeder 13. The vibrating feeder 13 is started to convey the raw material to the vibrating screen 15 at a uniform speed. The vibrating screen 15 is started, and the material is fed from 15 to 200 mm onto the screen, lifted to the top of the kiln, and impurities are screened out and discharged. The fine material belt 14 runs at a speed of 0.8 m / s to complete the screening of raw materials before entering the kiln.

[0042] The kiln top material distribution device ensures that the raw materials are evenly distributed inside the kiln, and the combustion system achieves complete calcination of kaolin by adjusting parameters in real time. The specific operation is as follows:

[0043] The kiln top uniform material distribution operation uses a four-point material distribution device and a disc material distributor to distribute the material into the furnace chamber of the kiln body 21. The material distribution radius covers 90% of the furnace chamber cross-section, so that the raw material forms a uniform material layer in the furnace chamber, avoiding the furnace wall effect (local low temperature) caused by the accumulation of raw material near the furnace wall.

[0044] The calcination parameters are set and the system is started via the DSC control module in control room 1. The core calcination parameters for kaolin are preset as follows: calcination temperature 1200-1300℃ (adjusted according to the kaolin grade in the raw material; 1250-1300℃ for a grade ≥90%, and 1200-1250℃ for a grade <90%), firebox negative pressure -15 to -100Pa (slight negative pressure to prevent flue gas from escaping and polluting the environment), and single-batch calcination time 2 hours. After the parameters are set, burner 9 is started, and the combustion fan is turned on simultaneously. 16. The combustion air blower 16 (air volume 3000m³ / h, air pressure 30kPa) delivers combustion air to the burner 9 through the combustion air pipe 18. The combustion air pipe 18 is equipped with an electric flow regulating valve, which is electrically connected to the PLC control module. The PLC module automatically adjusts the opening of the flow regulating valve (opening degree 30%-60%) according to the gas supply of the burner 9 (preset to 20m³ / h) to ensure that the ratio of gas to combustion air is stable at 1:10 (optimal combustion ratio), so as to achieve complete combustion of gas and reduce the emission of harmful gases.

[0045] Temperature sensors are installed in the calcination zone of the kiln body 21 for real-time control of the calcination process. Pressure sensors are also installed on the combustion and flue gas ducts. Each sensor collects various data in real time and transmits them to the PLC module in the control room 1.

[0046] If the temperature inside the kiln is lower than the preset value, the PLC module will automatically increase the gas supply of the corresponding burner 9 (increase by 0.5 m³ / h each time) and simultaneously increase the air volume of the combustion fan 16 (increase by 200 m³ / h each time) until the temperature rises back to the preset range.

[0047] If the furnace pressure is higher than -50Pa (e.g., rises to -30Pa), the PLC module automatically controls the flue gate valve (connected in series with the flue, not labeled) to increase the opening and increase the exhaust volume, so that the furnace pressure returns to -50Pa;

[0048] If localized rapid heating of the raw material is detected (e.g., temperature at a certain point > 1300℃), immediately reduce the gas supply to the corresponding burner 9 to prevent excessive sintering of kaolin and ensure uniform product quality.

[0049] After calcination, the kaolin needs to be cooled evenly before being discharged. If the discharge temperature is too high, water needs to be added to lower the temperature and prevent damage to the discharge equipment. The specific steps are as follows:

[0050] After the PLC module displays that the raw material has been calcined in the kiln 21 for 2 hours, the cooling fan 20 (air volume 8000 m³ / h, air pressure 25 kPa) is started. The air outlet of the cooling fan 20 is connected to the air cap 19. There are 36 sets of air caps 19, which are evenly distributed on the support grate at the bottom of the kiln 21 (each set is 300 mm apart). The air outlet of the air cap 19 is angled upward at 45° (to avoid cold air blowing directly on the material and causing agglomeration). The cooling air is dispersed by the air cap 19 and evenly blown onto the calcined material. The PLC module adjusts the air speed of the cooling fan 20 according to the temperature sensor data at the bottom of the kiln 21 (real-time monitoring of material temperature): when the material temperature is >800℃, the air speed is adjusted to the maximum; when the temperature drops to 400-800℃, the air speed is halved.

[0051] When the temperature drops below 150℃, adjust the fan speed to the minimum to ensure that the material cools down smoothly from 1100℃ to below 150℃ (cooling time 30 minutes) to avoid excessive temperature difference causing the material to crack.

[0052] After the material is discharged and metered and cooled, the PLC module sends a discharge signal to start the pallet discharge machine 3: the hydraulic pump of the pallet discharge machine 3 starts and outputs high-pressure hydraulic oil to the hydraulic cylinder. The hydraulic cylinder pushes the pull rod, and the pull rod drives the pallet (made of heat-resistant cast steel, 20mm thick) to move smoothly back and forth along the guide rail at the bottom of the kiln body 21 (stroke 80mm), pushing the cooled kaolin material to the hopper weighing discharge port 17;

[0053] The weight sensor inside the weighing outlet 17 of the funnel collects the weight of the material in real time, and the data is synchronously transmitted to the PLC module in the control room 1. The PLC module records the discharge amount of a single batch (preset single discharge is 4000kg). When the weight of the material inside the weighing outlet 17 of the funnel reaches 4000kg, the PLC module controls the discharge valve at the bottom of the funnel to open, and the material is unloaded into the subsequent finished product conveyor belt (unmarked) and transported to the finished product warehouse for storage, completing the single calcination discharge process.

[0054] To ensure the long-term stable operation of the vertical kiln, regular equipment maintenance is required, and an anomaly handling mechanism must be established. Specific measures are as follows:

[0055] Clean the screen of vibrating screen 15 daily to remove dust and impurities adhering to the screen, and check the screen tension. If the tension is insufficient, adjust it through the tension bolts at both ends of the screen.

[0056] Check the hydraulic oil level of pallet discharge machine 3 weekly: Open the oil level observation window of the hydraulic oil tank. If the oil level is lower than 1 / 3 of the scale line, add the same type of anti-wear hydraulic oil (such as 46# hydraulic oil). At the same time, check the seals of the hydraulic system and replace the aged seals to prevent oil leakage.

[0057] Monthly inspection of the supporting structure of the rain canopy 2 (arc-shaped steel structure, covering the top of the kiln body 21, control room 1 and burner 9): confirm that the steel structure is free of rust. If there is rust, sand it with sandpaper and then apply anti-rust paint. Inspect the drainage channel (slope 2°) at the edge of the rain canopy 2, clean the debris in the channel, and ensure that rainwater is discharged smoothly to prevent rainwater from seeping into the kiln body 21 or damaging the burner 9.

[0058] If the DSC module in control room 1 detects a sudden rise in temperature inside kiln 21 (e.g., exceeding 1300℃), the gas and air volume will be controlled by the PLC until the normal temperature is reached.

[0059] If the weight sensor data at the weighing outlet 17 of the funnel remains unchanged for an extended period (e.g., no change for more than 5 minutes), the PLC module will pause the automatic discharge system and require manual operation. The operator will be prompted to check: if the sensor wiring is loose, reconnect and secure the wiring; if the material inside the funnel is blocked, open the cleaning door on the side of the funnel and manually remove the blocked material.

[0060] If the combustion fan 16 malfunctions and stops, the PLC module immediately shuts off the gas valve of the burner 9 to prevent gas from accumulating in the combustion pipeline 18 and causing a safety accident. At the same time, it starts the backup combustion fan (if equipped). If there is no backup fan, the system will be restarted after the fault is cleared to ensure the continuous calcination process.

[0061] Through the above specific implementation process, this type of kaolin gas-fired calcining vertical kiln can achieve the following effects in practical applications:

[0062] The product quality has been significantly improved. Relying on the uniform distribution of the four-point feeding and disc feeding device, the precise temperature control of PLC+DSC, and the uniform cooling of multiple sets of air caps 19, the calcination qualification rate of kaolin has increased from 80% of traditional equipment to 95%. The product has no black core or blue core phenomenon, and the whiteness is stable at over 85%, meeting the demand for high-quality kaolin in high-end refractory materials, casting materials, ceramics, papermaking and other industries.

[0063] Energy consumption and cost reduction: The multi-layer composite refractory material layer of the kiln body 21 increases thermal efficiency by 15%. The ratio adjustment of the combustion fan 16 and burner 9 reduces the gas consumption per ton of raw material from 8m³ to 6m³. Automated feeding and control reduce the need for manual labor (only 2 people are required to operate, while traditional equipment requires 4 people). A single production line can save about 200,000 yuan in costs per year.

[0064] The furnace's micro-negative pressure design ensures compliance with environmental standards, preventing flue gas from escaping. Combined with the subsequent desulfurization and dust removal system, the concentration of particulate matter in the flue gas is ≤100mg / m³, and the concentration of SO2 is ≤100mg / m³, meeting the emission standards for air pollutants from industrial furnaces and kilns. This solves the problem of traditional calcining equipment failing to meet environmental standards and policy requirements.

[0065] The embodiments of the present invention are given for illustrative and descriptive purposes only, and are not intended to be exhaustive or to limit the invention to the forms disclosed. Many modifications and variations will be apparent to those skilled in the art. The embodiments were chosen and described in order to better illustrate the principles and practical application of the invention, and to enable those skilled in the art to understand the invention and to design various embodiments with various modifications suitable for a particular purpose.

Claims

1. A vertical kiln for calcining kaolin using gas, characterized in that: include: The height of the kiln body is set at 14-18 meters (21). Refractory material built into the inner wall of the kiln body (21); Hydraulic and mechanical reciprocating pallet discharge machine (3) installed at the bottom of the kiln body (21); A canopy (2) covering the upper part of the kiln body (21); A feeding system for conveying raw materials to the kiln body (21); A control system for controlling the operation of a kiln; Burners (9) and combustion fans (16) are arranged on the side of the kiln body (21). Combustion-supporting pipe (18) connecting combustion-supporting blower (16) and burner (9); A wind cap (19) is located at the bottom of the kiln body (21); Cooling fan (20) installed at the bottom of the kiln body (21); A funnel weighing device (17) connected to the feeding system. The feeding system includes a traveling mine car (5), a plate puller (4) that works with the traveling mine car (5), a transition hopper (6) located downstream of the plate puller (4), a feeding car (7) that connects to the transition hopper (6), a mine car weighing kiln (8) that receives the material discharged from the feeding car (7), a feeding inclined bridge (10) that connects to the mine car weighing kiln (8), a winch (11) that drives the feeding inclined bridge (10), a raw material hopper (12) located below the feeding inclined bridge (10), a vibrating feeder (13) that connects to the raw material hopper (12), a vibrating screen (15) that works with the vibrating feeder (13), and a fine material belt (14) that receives the material under the screen of the vibrating screen (15). The control system includes a control room (1) and PLC and DSC control modules located in the control room (1). The control system has temperature detection, pressure detection and frequency converter control functions. Among them, the pallet discharge machine (3), the combustion fan (16), the vibrating feeder (13), and the winch (11) are all electrically connected to the PLC and DSC control modules.

2. The kaolin gas-fired calcining vertical kiln as described in claim 1, characterized in that, The kiln body (21) adopts an improved steel structure, which includes annular reinforcing ribs spaced apart along the height direction of the kiln body (21), and the steel structure is welded to the kiln body foundation through foundation embedded parts.

3. The kaolin gas-fired calcining vertical kiln as described in claim 2, characterized in that, The refractory material layer is a multi-layer composite energy-saving structure, consisting of a high-alumina mullite refractory brick layer, a lightweight heat-insulating brick layer, and a refractory castable layer, arranged sequentially from the inside to the outside of the kiln body (21).

4. The kaolin gas-fired calcining vertical kiln as described in claim 3, characterized in that, The kiln top material distribution device is a four-point material distribution and disc material distribution structure, which achieves uniform material distribution in the kiln body through the material distributor.

5. The kaolin gas-fired calcining vertical kiln as described in claim 4, characterized in that, The pallet discharge machine (3) is equipped with a hydraulic pull rod drive mechanism, which includes a hydraulic pump, a hydraulic cylinder connected to the hydraulic pump, and a pull rod that is connected to the piston rod of the hydraulic cylinder at one end and to the pallet of the pallet discharge machine (3) at the other end; the pallet discharge machine (3) can also be a mechanical eccentric wheel type pallet discharge machine.

6. The kaolin gas-fired calcining vertical kiln as described in claim 5, characterized in that, The traveling mine car (5) (or using belt conveyor) travels along a preset track, and the discharge end of the traveling mine car (5) is correspondingly set with the feed end of the transition funnel (6); the discharge end of the transition funnel (6) is connected to the feed port of the loading car (7) through a chute, and the loading car (7) is transported to the feed end of the mine car weighing kiln (8) through the track.

7. The kaolin gas-fired calcining vertical kiln as described in claim 6, characterized in that, The PLC and DSC control modules have functions for adjusting combustion parameters, real-time detection of raw material weight, and automated control of the production process. They can adjust the gas supply of the burner (9), the air volume of the combustion fan (16), and the wind speed of the cooling fan (20) in real time according to the temperature signal inside the kiln.

8. The kaolin gas-fired vertical kiln as described in claim 7, characterized in that, The combustion blower (16) is installed in the lower part of the kiln body (21). The air outlet of the combustion blower (16) is connected to the air inlet of the burner (9) through the combustion pipe (18). The combustion pipe (18) is equipped with a flow regulating valve, which is electrically connected to the PLC and DSC control modules.

9. The kaolin gas-fired calcining vertical kiln as described in claim 8, characterized in that, The air caps (19) are in multiple sets and evenly distributed on the bottom support grate plate inside the kiln body (21). The air inlet end of the air caps (19) is connected to the air outlet pipe of the cooling fan (20). Cooling air is delivered to the lower part of the kiln body (21) through the air caps (19). Baffles are provided on both sides of the lower part of the kiln body (21).

10. The kaolin gas-fired calcining vertical kiln as described in claim 9, characterized in that, The canopy (2) is an arc-shaped steel structure canopy that covers the top of the kiln body (21) and above the control room (1). The edge of the canopy (2) extends to the top of the burner (9) on the side of the kiln body (21). A weight sensor is installed inside the weighing outlet (17) of the funnel, which is electrically connected to the PLC and DSC control modules.

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