A system and method for comprehensive utilization of thermal energy and regeneration of waste sand core

Abstract

A kind of heat comprehensive utilization waste sand core regeneration system and method, it is related to foundry field, including drying and crushing system, for crushing waste sand core into small block or granular;Temporary storage feeding system;High-temperature calcination system;Hot sand cooling system, it is set to calcination rotary kiln downstream;Reverse air cooling waste heat recovery system, including the air inlet formed by sand outlet and the air outlet formed by drying and crushing drum feed inlet, and air outlet is connected with negative pressure suction equipment, the discharge end of the calcination rotary kiln and the feed end of cooling drum are sealingly communicated, the feed end of the calcination rotary kiln and drying and crushing drum are sealingly communicated with one end close to screening mechanism.Cooling hot sand after heat exchange high-temperature hot air reverse flow, improve the combustion effect in calcination kiln, and preheat material in drying and crushing drum, fully recover the waste heat carried by calcination hot sand, greatly reduce the gas consumption of calcination process, solve the problem that traditional equipment is dispersedly arranged and transfers and causes a large amount of heat loss.

Description

TECHNICAL FIELD

[0001] The present invention relates to the technical field of casting sand core recovery, in particular to a waste sand core regeneration system and method with comprehensive heat energy utilization. BACKGROUND ART

[0002] In the production process of resin sand casting molding, a large amount of waste sand cores are continuously produced in the core making and molding processes. These waste sand cores are mixed with metal flashes, iron chips, caked sand masses and cured resin binders that fall off during the molding process. If they are directly disposed as industrial solid waste, it will not only greatly increase the cost of solid waste stacking, transshipment and disposal in the casting plant, but also cause a large amount of loss of molding sand resources for molding, which does not meet the requirements of green circular production in the casting industry. At present, the traditional waste sand regeneration production line matched with casting molding workshops has a relatively simple process, and most of them are only provided with a single high-temperature roasting process. It is difficult to completely pyrolyze and remove the trace molding residual resin wrapped in the internal pores of sand particles, and the cleanliness of reclaimed sand cannot meet the reuse standards for molding and core making.

[0003] In addition, the mainstream regeneration equipment on the market are relatively scattered among various devices, requiring the waste to be transported back and forth to different devices, which will cause serious heat loss during transportation. Moreover, the discharge position generally adopts water spray to cool the high-temperature hot sand after roasting. On the one hand, water spray cooling will greatly increase the moisture content of the sand, and an additional drying process is required to remove the moisture after cooling, which consumes extra heat energy. In addition, when water meets high-temperature sand, it vaporizes instantly, forming mixed flue gas with high humidity, high temperature and high dust. To avoid clogging and high-temperature burning of conventional dust removal filter bags, it is necessary to equip a high-cost high-temperature baghouse dust collector at the discharge end of sand output. At the same time, water spray produces a large amount of sewage, which increases the sewage treatment burden of the casting molding workshop. The high-temperature waste heat carried by the hot sand is all lost with water vapor, which cannot be recovered and recycled. The roasting process consumes a large amount of blast furnace gas, and the overall operating energy consumption of the casting molding production line is relatively high. SUMMARY OF THE INVENTION

[0004] In order to solve the above problems of large heat loss and insufficient resin removal effect of the existing waste sand core regeneration system, the present invention provides a waste sand core regeneration system and method with comprehensive heat energy utilization.

[0005] The technical solution of the present invention is as follows: A waste sand core regeneration system with comprehensive heat energy utilization, characterized by comprising: a drying and crushing system, configured to crush waste sand cores into small blocks or granular materials, comprising a drying and crushing drum, wherein one end of the drying and crushing drum is provided with a feed port, the other end close to the tail is provided with a discharge port, and a screening mechanism is integrated at the discharge port; a temporary storage and feeding system, comprising a temporary storage hopper arranged at the discharge port side of the drying and crushing drum, and a feeding device is arranged at the discharge end of the temporary storage hopper; A high-temperature roasting system is used for high-temperature pyrolysis and decomposition of the cured resin binder in small block or granular waste sand cores, including a roasting rotary kiln, whose feed end is used to receive the waste sand cores conveyed by the feeding equipment. A hot sand cooling system includes a cooling drum located downstream of a calcining rotary kiln, with its feed end connected to the discharge end of the calcining rotary kiln, and a sand outlet opened at the end of the cooling drum. The reverse air-cooled waste heat recovery system includes an air inlet formed by the sand outlet and an air outlet formed by the feed inlet of the drying and crushing drum. The air outlet is connected to a negative pressure suction device. The discharge end of the calcining rotary kiln is sealed and connected to the feed end of the cooling drum. The feed end of the calcining rotary kiln is sealed and connected to the end of the drying and crushing drum near the screening mechanism, forming a reverse airflow channel from the air inlet through the cooling drum, the calcining rotary kiln, the drying and crushing drum to the air outlet. The control system is electrically connected to the drying and crushing system, the temporary storage and feeding system, the high-temperature roasting system, the hot sand cooling system, and the reverse air-cooled waste heat recovery system. It can control the opening and closing of the above systems, monitor and control the rotation speed of the drying and crushing drum, the roasting rotary kiln, and the cooling drum in real time, monitor the temperature inside the roasting rotary kiln in real time, and control the gas flow rate required for combustion.

[0006] To facilitate monitoring and control of the calcination temperature, address the issue of high gas consumption, and achieve closed-loop temperature control within the kiln, ensuring complete resin pyrolysis while reducing gas energy consumption, a gas nozzle is installed on one side of the calcination rotary kiln. A proportional regulating valve is installed between the gas nozzle and the gas supply equipment. A high-temperature resistant temperature acquisition element is installed inside the calcination rotary kiln, and both the element and the proportional regulating valve are electrically connected to the control system.

[0007] To address the problem of iron filings and metal burrs mixed in with existing waste sand cores, resulting in recycled sand quality that does not meet reuse standards, magnetic impurities are separated and removed during the conveying stage. The feeding equipment includes a magnetic separator conveyor for receiving waste sand cores from a temporary storage bucket. A bucket elevator is connected to the discharge end of the magnetic separator conveyor, and the discharge end of the bucket elevator is connected to the inlet of the drying and crushing drum.

[0008] To address the issue of significant heat loss due to the dispersed layout of existing equipment and hot air leakage, and to ensure the airtightness of the reverse airflow channel, reduce waste heat loss, and improve waste heat recovery efficiency, the discharge end of the calcining rotary kiln is sealed and connected to the drying and crushing drum via a connecting sealing sleeve.

[0009] To optimize the installation layout of the bucket elevator and drying / crushing drums, and to address the sealing failure at the material inlet, the bucket elevator is fitted with a through-seal sleeve from bottom to top. Its outlet end is inclined downwards, penetrating the through-seal sleeve to connect with the inlet end of the calcining rotary kiln, and all these penetration points are sealed.

[0010] To address the issues of loose equipment layout, short heat exchange stroke, and poor cooling effect in existing production lines, material transport is achieved by gravity, while extending the heat exchange path of the hot sand, improving waste heat recovery efficiency, and reducing equipment footprint. The drying and crushing drum, calcining rotary kiln, and cooling drum are all arranged at an angle, meaning the feed end is higher than the discharge end, and the drying and crushing drum is collinear with the axis of the calcining rotary kiln. The cooling drum is located below the calcining rotary kiln, and the extension direction of the cooling drum from the feed end to the discharge end is opposite to the extension direction of the calcining rotary kiln.

[0011] To minimize the impact of hot gas recirculation on the bucket elevator and optimize the overall spatial layout, the bucket elevator is arranged vertically, with its axis offset from that of the calcining rotary kiln.

[0012] A method for regenerating waste sand cores through comprehensive utilization of thermal energy, using the aforementioned waste sand core regeneration system, includes the following steps: S1: Start the negative pressure suction equipment to create a negative pressure environment for the drying and crushing drum, the calcining rotary kiln and the cooling drum; S2: At a preset time interval t, the drying and crushing drum is started and waste sand cores are continuously fed into the drum. As the drum rotates and tumbles, the waste sand cores fall into the temporary storage hopper from the screening mechanism after drying and crushing are completed. S3: Start the feeding equipment and the roasting rotary kiln and open the temporary storage hopper. The crushed waste sand core is formed into small blocks or granules and fed into the roasting rotary kiln for roasting to form high-temperature hot sand. S4: The cooling drum is started simultaneously with the calcining rotary kiln. The high-temperature hot sand enters the cooling drum and tumbles inside. The cold air and the high-temperature sand exchange heat through convection. The residual organic binder in the hot sand is decomposed by secondary combustion by the hot sand itself to form recycled sand particles. The hot air after heat exchange and heating flows through the calcining rotary kiln and the drying and crushing drum in sequence along the counter-flow channel. The waste heat of the hot air is used to preheat the waste sand core to be processed in the drying and crushing drum. The hot air is finally extracted by the negative pressure suction device through the air outlet at the feed port of the drying and crushing drum. S5: The recycled sand particles, after being cooled and subjected to secondary burnout treatment, are discharged from the sand outlet of the cooling drum.

[0013] To address the issue of large waste sand cores directly entering the downstream equipment, resulting in a high crushing and impurity removal load and impacting the overall production line's processing capacity, and to perform pre-magnetic separation on the waste sand to reduce metal impurities such as iron filings entering the drum, the system also includes a pretreatment system. This system can perform pre-magnetic separation and pre-crushing of the waste sand cores, and continuously feed the waste sand cores into the drying and crushing drum in step S2.

[0014] To address the issues of overcrowded equipment layout and interference between upstream and downstream equipment in the foundry workshop, optimize the workshop layout, and reserve space for maintenance, the pretreatment system is located upstream of the drying and crushing system. Furthermore, the direction in which the pretreatment system transports waste sand cores is perpendicular to the direction in which the drying and crushing system transports waste sand cores to the high-temperature roasting system.

[0015] The beneficial effects of this invention are as follows: This invention is a waste sand core regeneration system and method for comprehensive utilization of thermal energy. It sets up a reverse air-cooled waste heat recovery system, forming a closed reverse airflow channel that runs through the cooling drum, the roasting rotary kiln, and the drying and crushing drum. It eliminates the traditional water spray cooling method. External cold air enters from the sand outlet of the cooling drum and exchanges heat with the high-temperature hot sand through convection. On the one hand, during the air cooling process, the heat storage of the hot sand enables the residual resin binder inside the sand particle pores to achieve secondary and complete combustion, which significantly improves the cleanliness of the regenerated sand and meets the standards for molding and core making reuse. On the other hand, the high-temperature hot air after the heat exchange with the cooling sand flows back in reverse, which improves the combustion effect in the roasting kiln and preheats the material in the drying and crushing drum, fully recovers the waste heat carried by the roasting hot sand, greatly reduces the gas consumption in the roasting process, and solves the problem of large heat loss caused by the decentralized arrangement and transportation of traditional equipment.

[0016] The entire system adopts a closed series sealed connection structure, with materials flowing in a closed manner between each roller, without intermediate transfer spillage or heat leakage. The integration between the various devices in the regeneration system is high, while avoiding the increase in sand moisture content caused by water spray cooling and the need for subsequent additional drying. It also eliminates the high humidity and high temperature dust and flue gas generated by water spray vaporization, eliminating the need for expensive high temperature bag dust collectors and generating no cooling wastewater, reducing the pressure on workshop wastewater treatment, and realizing the green recycling of waste sand cores. Attached Figure Description

[0017] The solutions and advantages of this application will become clear to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the scope of the invention.

[0018] In the attached diagram: Figure 1 This is a schematic diagram of the system structure in Example 1; Figure 2 This is a schematic diagram showing the positions of the pretreatment system and the drying and crushing drum in Example 2; Figure 3 for Figure 2 Left view of the preprocessing system; The components represented by the various reference numerals in the diagram are: 1. Drying and crushing system; 11. Drying and crushing drum; 12. Feed inlet; 13. Discharge outlet; 14. Screening mechanism; 2. Temporary storage and feeding system; 21. Temporary storage hopper; 22. Magnetic separator conveyor; 23. Bucket elevator; 3. High-temperature roasting system; 31. Roasting rotary kiln; 32. Gas nozzle; 4. Hot sand cooling system; 41. Cooling drum; 42. Sand outlet; 5. Reverse air cooling waste heat recovery system; 51. Air inlet; 52. Air outlet; 53. Reverse airflow channel; 54. Air outlet pipe; 6. Connecting sealing sleeve; 7. Pretreatment system; 71. Pre-crushing equipment; 72. Pre-magnetic separator conveyor; 73. Plate chain elevator; 74. Waste sand storage bin; 75. Intermediate magnetic separator conveyor; 76. Feeding elevator; 77. Suspended magnetic separator; 78. Finished waste sand conveyor; 8. Waste sand core output machine. Detailed Implementation

[0019] Exemplary embodiments of this disclosure will now be described in more detail with reference to the accompanying drawings. It should be noted that these embodiments are provided to enable a more thorough understanding of this disclosure and to fully convey the scope of this disclosure to those skilled in the art. This disclosure can be implemented in various forms and should not be limited to the embodiments set forth herein.

[0020] Example 1 This embodiment discloses a waste sand core recycling system for comprehensive thermal energy utilization, belonging to the field of foundry waste sand recycling technology. It is mainly applied to the harmless treatment and recycling of waste sand cores in resin sand casting production lines. Currently, traditional waste sand recycling production lines rely solely on a single high-temperature roasting process to process waste sand, and the cleanliness of the recycled sand is difficult to meet the standards for molding and core making reuse. At the same time, existing recycling equipment is relatively dispersed, the material transfer process is cumbersome, and heat loss during the transfer process is serious. In addition, conventional processes generally use water spraying to cool the high-temperature hot sand after roasting. Water spraying cooling significantly increases the moisture content of the sand, requiring additional drying and dehydration, resulting in a large amount of heat energy loss. After the high-temperature sand vaporizes upon contact with water, it forms a mixed flue gas with high humidity, high temperature, and high dust, requiring a high-cost high-temperature bag filter. At the same time, a large amount of production wastewater is generated, significantly increasing the burden of wastewater treatment in the workshop. The waste heat of the hot sand is completely lost with the water vapor and cannot be recovered, ultimately resulting in huge gas consumption in the roasting process. The entire production line has high energy consumption and poor production economy.

[0021] This solution optimizes the design of an integrated sealed series waste sand core regeneration system to address the aforementioned technical deficiencies. The system includes a drying and crushing system 1, a temporary storage and feeding system 2, a high-temperature roasting system 3, a hot sand cooling system 4, a reverse air cooling waste heat recovery system 5, and a control system. The systems work together to achieve continuous, low-energy, and high-cleanliness regeneration of waste sand cores.

[0022] Among them, combined Figure 1The drying and crushing system 1 is used to complete the drying, crushing and screening of waste sand cores. The core component is the drying and crushing drum 11. One end of the drying and crushing drum 11 is provided with a feed port 12 for receiving the waste sand cores to be processed, and the other end is provided with a discharge port 13 near the tail end. The discharge port 13 integrates a screening mechanism 14. It should be noted that, as shown in the figure, the discharge port 13 of this scheme is not located at the end of the drying and crushing drum 11, but is located on the side near the end. The location where the screening mechanism 14 is installed in the figure can screen the crushed material into small blocks or granular sand, ensuring uniform and stable subsequent roasting treatment. The temporary storage and feeding system 2 is arranged on one side of the discharge port 13 of the drying and crushing drum 11. It includes a temporary storage hopper 21 for temporarily buffering sand. An electric control valve can be installed at the bottom of the temporary storage hopper 21 and electrically connected to the control system to control the automatic discharge of the temporary storage hopper 21. The discharge end of the temporary storage hopper 21 is equipped with a feeding device, which includes a magnetic separation conveyor 22 and a bucket elevator 23. The magnetic separation conveyor 22 receives the sand output from the temporary storage hopper 21 and can further screen out iron filings and metal impurities mixed in the crushed sand. The bucket elevator 23 receives the discharge from the magnetic separation conveyor 22, and the discharge end of the bucket elevator 23 is connected to the feed end of the subsequent high-temperature roasting system 3 to achieve stable and continuous conveying of sand.

[0023] In this embodiment, the high-temperature roasting system 3 is used for high-temperature pyrolysis and decomposition of the solidified resin binder inside the sand material. It includes a roasting rotary kiln 31, whose feed end receives small chunks or granular waste sand cores conveyed by a feeding device. The resin binder is removed through pyrolysis in a high-temperature environment. During the binder removal process, the small chunks of waste sand cores collide and are conveyed by the rotation of the rotary kiln, forming granular waste sand cores. A gas nozzle 32 is installed on one side of the roasting rotary kiln 31. A proportional regulating valve is installed between the gas nozzle 32 and the gas supply equipment. A high-temperature resistant temperature acquisition element is installed inside the roasting rotary kiln 31. Both the temperature acquisition element and the proportional regulating valve are electrically connected to the control system. The control system can monitor the kiln temperature in real time and dynamically adjust the gas flow rate according to the actual working conditions to achieve precise and constant kiln temperature control, avoiding incomplete resin pyrolysis due to insufficient temperature or energy waste due to excessively high temperature.

[0024] Based on the above system, combined with Figure 1 The hot sand cooling system 4 is located downstream of the high-temperature roasting system 3 and includes a cooling drum 41. The feed end of the cooling drum 41 is connected to the discharge end of the roasting rotary kiln 31. A sand outlet 42 is opened at the end of the cooling drum 41 to discharge the cooled recycled sand particles.

[0025] It should be noted that this solution also features an innovative design for the location layout of multiple systems. Specifically, the drying and crushing drum 11, the calcining rotary kiln 31, and the cooling drum 41 are all arranged at an angle, with the height of the feed end of each drum being higher than the height of the discharge end. The sand is automatically conveyed by its own weight. The drying and crushing drum 11 and the calcining rotary kiln 31 are arranged on the same axis to ensure smooth and stable material conveying. The cooling drum 41 is arranged below the calcining rotary kiln 31, and the extension direction of the cooling drum 41 is opposite to that of the calcining rotary kiln 31, which effectively extends the heat exchange stroke of the hot sand and improves the cooling and waste heat recovery efficiency. In other words, the cooling drum 41 is installed below the calcining rotary kiln 31 by stacking installation components, which effectively saves installation space.

[0026] In this embodiment, the control system serves as the core control unit of the entire machine, and is electrically connected to each system. It can uniformly control the start and stop of the entire set of equipment, monitor and adjust the operating speed of the drying and crushing drum 11, the roasting rotary kiln 31, and the cooling drum 41 in real time, match different material processing speeds, and accurately regulate the gas combustion flow rate in conjunction with temperature monitoring data to achieve full-process automated intelligent control. Moreover, the magnetic separation conveyor 22 adopts a metering conveyor belt, which can weigh the waste sand on the belt and achieve linkage adjustment with the temperature and gas supply in the roasting rotary kiln 31 to ensure stable roasting effect.

[0027] The core invention of this solution is the design of a reverse air-cooled waste heat recovery system 5, which differs from existing technologies. This system includes an air inlet 51 formed by the sand outlet 42 of the cooling drum 41 and an air outlet 52 formed by the feed inlet 12 of the drying and crushing drum 11. The air outlet 52 is connected to a negative pressure suction device via an air outlet pipe 54. The discharge end of the calcining rotary kiln 31 and the feed end of the cooling drum 41, as well as the feed end of the calcining rotary kiln 31 and the end of the drying and crushing drum 11 near the screening mechanism 14, are all sealed together by a connecting sealing sleeve 6. This forms a closed reverse airflow channel 53 from the air inlet 51 through the cooling drum 41, the calcining rotary kiln 31, and the drying and crushing drum 11 to the air outlet 52. Figure 1 As shown by the dashed arrow, waste heat is recovered and utilized in stages.

[0028] It should be noted that this solution differs from the existing water-cooling method. A lifting assembly is installed on the inner wall of the cooling drum 41. This assembly can be a lifting plate or similar structure, which is part of the existing cooling drum 41 structure and will not be elaborated further. It is used to agitate the high-temperature hot sand formed after crushing and high-temperature roasting inside the drum. A negative pressure suction device draws combustion-supporting gas, such as oxygen-containing air, into the cooling drum 41 through the air inlet 51. This gas contacts the surface of the agitated high-temperature hot sand, creating a wind-sand convection heat exchange mode. On one hand, as the cold air exchanges heat with the hot sand and gradually heats up, it fully utilizes the residual heat of the incandescent sand, combining with air for secondary combustion. This further burns the incompletely roasted residual resin and trace organic matter on the surface and in the pores of the sand particles. The first step involves complete combustion and decomposition to achieve secondary deep purification. On the other hand, after the heat exchange is completed in the secondary combustion, the airflow flows into the roasting rotary kiln 31 through the airflow channel. The hot air carrying heat can directly preheat the roasting rotary kiln 31, increase the initial temperature inside the kiln, and assist combustion, reducing the amount of gas supply required for the roasting rotary kiln 31 to maintain the set working temperature. Subsequently, the heated airflow continues to flow into the drying and crushing drum 11 through the reverse airflow channel 53. The heat is used to preheat and dry the raw waste sand core to be processed entering the drying and crushing drum 11, further recovering the residual heat in the airflow. Finally, the cooled airflow carries the dust generated during the drying and crushing process and is uniformly extracted by the negative pressure suction device through the air outlet 52 and sent to the subsequent dust removal and purification device for emission in compliance with standards.

[0029] In addition, the bucket elevator 23 adopts a vertical arrangement structure. The bucket elevator 23 passes through the connecting sealing sleeve 6 from bottom to top, and the discharge end passes through the connecting sealing sleeve 6 at an angle downward and connects with the feed end of the calcining rotary kiln 31. All penetration positions are sealed to effectively prevent air leakage, heat leakage and dust leakage. Moreover, its axis is offset from the axis of the calcining rotary kiln 31, which can reduce the area of ​​the bucket elevator 23 shell that is constantly eroded by the return hot air. On the one hand, it reduces the corrosion and wear of the conveying equipment by the high temperature airflow and extends the service life of the equipment. On the other hand, it also reduces the obstruction of the hot airflow and improves the efficiency of heat utilization.

[0030] This solution also discloses a method for the comprehensive utilization of thermal energy to regenerate waste sand cores, which is compatible with the above-mentioned regeneration system. The specific operation steps are as follows: S1: Start the negative pressure suction device to create a stable negative pressure sealed environment inside the cooling drum 41, the calcining rotary kiln 31 and the drying and crushing drum 11, ensuring that the cooling airflow entering from the air inlet flows along the airflow channel.

[0031] S2: The interval is a preset time t, which is 1-5 minutes in this embodiment. This interval ensures that the negative pressure suction device creates a negative pressure environment inside the cylinder. The drying and crushing drum 11 is started, and waste sand cores are continuously conveyed into the drum. The waste sand cores are continuously tumbled under the rotation of the drum. The hot airflow that enters from the airflow channel at the same time completes the drying and dehydration, and completes the crushing and refining operation. The small block and granular sand materials that are qualified by crushing and screening fall from the screening mechanism 14 into the temporary storage hopper 21 for temporary storage.

[0032] S3: Then start the first conveying equipment and the roasting rotary kiln 31, that is, turn on the magnetic separator conveyor 22 and the bucket elevator 23, and start the temporary storage hopper 21 to discharge material. After the magnetic separator conveyor 22 reaches the preset amount of waste sand, close the temporary storage hopper 21. The sand is magnetically separated to remove impurities and then conveyed to the roasting rotary kiln 31. The solidified resin binder inside the sand is decomposed by high-temperature roasting and cracking to form high-temperature hot sand. Moreover, the control system controls the corresponding amount of gas supply based on the preset amount of waste sand on the magnetic separator conveyor 22.

[0033] S4: The cooling drum 41 is started synchronously. The high-temperature hot sand enters the cooling drum 41 and continues to tumble. The outside cold air enters the equipment through the sand outlet 42 and the air inlet 51, forming a counter-current heat exchange with the high-temperature sand. The hot sand relies on its own heat storage to complete the secondary combustion and decomposition of the residual trace organic binder, further improving the cleanliness of the sand. The hot air after heat exchange and heating flows through the counter-current airflow channel 53 in sequence through the roasting rotary kiln 31 and the drying and crushing drum 11. The waste heat is used to assist the combustion in the kiln and preheat the waste sand core to be processed in the drying and crushing drum 11, which greatly reduces the energy consumption of roasting gas and drying. The low-temperature exhaust gas after heat exchange is finally extracted by negative pressure through the air outlet 52 and discharged after being purified by the purification device.

[0034] S5: The qualified recycled sand particles that have completed cooling and purification are finally discharged stably from the sand outlet 42 of the cooling drum 41, completing the entire recycling process. Subsequently, waste sand is continuously introduced to perform the above steps until the same batch of waste sand is processed.

[0035] Example 2 In Example 1, pre-crushed waste sand cores can be fed into the drying and grinding system. Unlike Example 1, this example includes a pretreatment system upstream of the drying and crushing system 1. Figure 2 This illustrates the positional relationship between the pretreatment system 7 and the drying and crushing drum 11, that is... Figure 1 Looking to the left, the drying and crushing drum 11 and the subsequent calcining rotary kiln 31, etc., are perpendicular to the direction shown in the figure. Figure 2Arranged inwards on the paper surface, the pretreatment system 7 includes a pre-crushing system and a conveying system, which can perform pre-crushing and pre-magnetic separation of the raw waste sand cores. In step S2, the conveying system supplies the crushed waste sand cores to the drying crushing drum 11. The pretreatment system is located downstream of the waste sand core conveying system. The waste sand core conveying system includes a waste sand core output machine 8, which is used to output the waste sand cores to be processed in batches. In this embodiment, the pre-crushing system includes a pre-crushing device 71, which can be a toothed roller crusher, used to receive the waste sand cores at the output end of the waste sand core output machine 8 and crush them. A pre-magnetic separation conveyor 72 is provided at the discharge end of the pre-crushing device 71 to receive the waste sand cores, which can perform primary magnetic separation on the pre-crushed waste sand cores to reduce the metal substances contained in the sand cores entering the subsequent equipment.

[0036] In addition, the conveying system includes a plate chain elevator 73 installed at the discharge end of the front magnetic separator 72. The discharge end of the latter is equipped with a waste sand storage bin 74 for storing and buffering the crushed waste sand cores. A mid-section magnetic separator 75 is installed at the discharge end of the waste sand storage bin 74, and a feeding elevator 76 is installed at its discharge end. The discharge end of the feeding elevator 76 is sealed and connected to the feed inlet 12 of the drying and crushing drum 11, forming a feeding route from the waste sand core conveyor to the drying and crushing drum 11.

[0037] Moreover, combined Figure 2 and Figure 3 The pretreatment system also includes a suspended magnetic separator 77, which is suspended above the waste sand core output machine 8 and located upstream of the pre-crushing equipment 71. It can adsorb large iron impurities mixed in the waste sand core material flow, avoid large iron objects from hitting and damaging the downstream toothed roller crusher, improve the safety of equipment operation, and reduce the probability of metal impurities entering the recycled sand material from the source.

[0038] In addition, a finished waste sand conveyor 78 is also provided in the extension direction of the intermediate magnetic separation conveyor 75. The discharge end is set corresponding to the feed end of the feeding elevator 76. It is symmetrically set with the intermediate magnetic separation conveyor 75 relative to the feeding elevator 76. When the amount of waste sand core in the pretreatment system is insufficient, crushed waste sand can be added through the finished waste sand conveyor 78, thereby improving the adaptability of this system to waste sand processing.

[0039] Furthermore, the waste sand storage silo 74 is equipped with a level gauge, and the intermediate magnetic separation conveyor 75 is equipped with a weight sensor. Both are electrically connected to the control system. The silo is opened based on the level signal fed back by the level gauge, and the waste sand storage silo 74 or the intermediate magnetic separation conveyor 75 is closed based on the weight signal fed back by the gravity sensor after the preset weight is reached.

[0040] It should be noted that the direction in which the pretreatment system conveys waste sand cores is perpendicular to the direction in which the drying and crushing system 1 to the high-temperature roasting system 3 conveys waste sand cores. In other words, the direction of the waste sand core conveyor to the feeding elevator 76 is perpendicular to the flow direction during the waste sand core drying process. Figure 2 As shown in the attached diagram, the solid arrow at the bottom represents the sand core conveying process of the pretreatment system 7. Upon reaching the position of the drying and crushing drum 11, it moves vertically... Figure 2 The paper-side sand core is fed inward, ensuring that the pretreatment system and the drying and crushing system are staggered, saving workshop layout space and facilitating flexible planning and layout of the production line according to the existing site. It does not require large-scale modification and adjustment of the original factory structure, thus reducing the overall cost of production line modification and installation.

Claims

1. A thermal energy comprehensive utilization waste sand core regeneration system, characterized in that, include: The drying and crushing system (1) is used to crush waste sand cores into small blocks or granules, including a drying and crushing drum (11), which has a feed inlet (12) at one end and a discharge outlet (13) at the other end near the tail end, and a screening mechanism (14) is integrated at the discharge outlet (13). The temporary storage feeding system (2) includes a temporary storage hopper (21) located on the side of the discharge port (13) of the drying and crushing drum (11), and a feeding device is provided at the discharge end of the temporary storage hopper (21); The high-temperature roasting system (3) is used for high-temperature pyrolysis and decomposition of the solidified resin binder in small block or granular waste sand cores, including a roasting rotary kiln (31), whose feed end is used to receive the waste sand cores conveyed by the feeding equipment. The hot sand cooling system (4) includes a cooling drum (41) which is located downstream of the calcining rotary kiln (31) and whose feed end is connected to the discharge end of the calcining rotary kiln (31). A sand outlet (42) is opened at the end of the cooling drum (41). The reverse air-cooled waste heat recovery system (5) includes an air inlet (51) formed by the sand outlet (42) and an air outlet (52) formed by the feed inlet (12) of the drying and crushing drum (11). The air outlet (52) is connected to a negative pressure suction device. The discharge end of the roasting rotary kiln (31) is sealed and connected to the feed end of the cooling drum (41). The feed end of the roasting rotary kiln (31) is sealed and connected to the end of the drying and crushing drum (11) near the screening mechanism (14). A reverse airflow channel (53) is formed from the air inlet (51) through the cooling drum (41), the roasting rotary kiln (31), the drying and crushing drum (11) to the air outlet (52). The control system is electrically connected to the drying and crushing system (1), the temporary storage and feeding system (2), the high-temperature roasting system (3), the hot sand cooling system (4), and the reverse air cooling waste heat recovery system (5), respectively. It can control the opening and closing of the above systems, monitor and control the rotation speed of the drying and crushing drum (11), the roasting rotary kiln (31), and the cooling drum (41) in real time, monitor the temperature inside the roasting rotary kiln (31) in real time, and control the gas flow required for combustion.

2. The waste sand core regeneration system for comprehensive utilization of thermal energy according to claim 1, characterized in that, A gas nozzle (32) is provided on one side of the calcining rotary kiln (31), and a proportional regulating valve is provided between the gas nozzle (32) and the gas supply equipment. A high-temperature resistant temperature acquisition element is provided inside the calcining rotary kiln (31), and both the element and the proportional regulating valve are electrically connected to the control system.

3. The waste sand core regeneration system for comprehensive utilization of thermal energy according to claim 1, characterized in that, The feeding equipment includes a magnetic separator conveyor (22), which is used to receive the waste sand core output from the temporary storage bucket (21). The discharge position of the magnetic separator conveyor (22) is connected to a bucket elevator (23), and the discharge end of the bucket elevator (23) is connected to the feed inlet (12) of the drying and crushing drum (11).

4. The waste sand core regeneration system for comprehensive utilization of thermal energy according to claim 3, characterized in that, The discharge end of the calcining rotary kiln (31) is sealed and connected to the drying and crushing drum (11) through a connecting sealing sleeve (6).

5. The waste sand core regeneration system for comprehensive utilization of thermal energy according to claim 4, characterized in that, The bucket elevator (23) is installed through the connecting sealing sleeve (6) from bottom to top. Its discharge end is inclined downward through the connecting sealing sleeve (6) and connected to the feed end of the roasting rotary kiln (31). All the above-mentioned through positions are sealed.

6. The waste sand core regeneration system for comprehensive utilization of thermal energy according to claim 1, characterized in that, The drying and crushing drum (11), the calcining rotary kiln (31) and the cooling drum (41) are all arranged at an inclination, that is, the feeding end is set higher than the discharging end, and the drying and crushing drum (11) and the calcining rotary kiln (31) are collinear. The cooling drum (41) is located below the calcining rotary kiln (31), and the extension direction of the cooling drum (41) from the feed end to the discharge end is opposite to the extension direction of the calcining rotary kiln (31).

7. A waste sand core regeneration system for comprehensive utilization of thermal energy according to claim 5, characterized in that, The bucket elevator (23) is arranged vertically, and its axis is offset from the axis of the rotary kiln (31).

8. A method for regenerating waste sand cores through comprehensive utilization of thermal energy, using the waste sand core regeneration system for comprehensive utilization of thermal energy as described in any one of claims 1-7, characterized in that, Includes the following steps: S1: Start the negative pressure suction equipment to establish a negative pressure environment for the drying and crushing drum (11), the calcining rotary kiln (31) and the cooling drum (41); S2: At a preset time interval t, start the drying and crushing drum (11) and continuously feed waste sand cores into the drum. As the drum rotates and flips, after drying and crushing, the waste sand cores fall into the temporary storage hopper (21) from the screening mechanism (14). S3: Start the feeding equipment and the roasting rotary kiln (31) and open the temporary storage hopper (21). The crushed waste sand core is formed into small blocks or granules and fed into the roasting rotary kiln (31) for roasting to form high-temperature hot sand. S4: Simultaneously with the calcining rotary kiln (31), the cooling drum (41) is started. The high-temperature hot sand enters the cooling drum (41). The hot sand tumbles in the cooling drum (41). The cold air and the high-temperature sand exchange heat through convection. Relying on the heat storage of the hot sand itself, the residual organic binder of the hot sand is burned and decomposed for the second time to form recycled sand particles. The hot air after heat exchange and heating flows through the counter-current airflow channel (53) and passes through the calcining rotary kiln (31) and the drying and crushing drum (11) in sequence. The waste heat of the hot air is used to preheat the waste sand core to be treated in the drying and crushing drum (11). The hot air is finally extracted by the negative pressure suction device through the air outlet (52) at the feed inlet (12) of the drying and crushing drum (11). S5: The recycled sand particles that have been cooled and burned off twice are discharged from the sand outlet (42) of the cooling drum (41).

9. A method for comprehensive utilization of thermal energy and regeneration of waste sand cores according to claim 8, characterized in that, The system also includes a pretreatment system (7) that can perform pre-magnetic separation and pre-crushing of waste sand cores and continuously feed waste sand cores into the drying and crushing drum (11) in step S2.

10. A method for comprehensive utilization of thermal energy and regeneration of waste sand cores according to claim 9, characterized in that, The pretreatment system (7) is located upstream of the drying and crushing system (1), and the direction in which the pretreatment system (7) transports waste sand cores is perpendicular to the direction in which the drying and crushing system (1) transports waste sand cores to the high-temperature roasting system (3).

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