A triethylamine circulation system and method for cold-box core shooting production

Abstract

A triethylamine circulation system and method for cold-box core shooting production, comprising a triethylamine supply system for supplying high-purity triethylamine in the core shooting production process; an amine supply pipeline, the discharge port of the triethylamine supply system is communicated with the amine supply pipeline, and the discharge port of the amine supply pipeline is communicated with a core shooting system; a tail gas recovery system for recovering and filtering tail gas mixed with triethylamine gas after catalytic reaction; a waste gas recovery pipeline for communicating the core shooting system with the tail gas recovery system; a gas storage tank, the gas inlet of the gas storage tank is communicated with a filtering air bag, and the gas outlet is communicated with one end of the amine supply pipeline away from the core shooting system; a valve system, comprising a blowing proportional valve for controlling the triethylamine gas pressure entering the core shooting system, and a program-controlled stop valve installed on the waste gas recovery pipeline for controlling the flow and on-off of the recovered tail gas. A closed-loop gas recovery circulation system is constructed, the reuse rate of triethylamine raw materials is greatly improved, and the raw material procurement cost of enterprises is significantly reduced.

Description

Technical Field

[0001] This invention relates to the field of core preparation technology, specifically to a triethylamine recycling system and method for cold box core shooting production. Background Technology

[0002] Triethylamine cold box core making is a mainstream room temperature rapid core making technology in the foundry industry. It has advantages such as high efficiency, high precision, and low energy consumption, and is widely used in the production of precision castings for automobiles, construction machinery, and cast pipes. Traditional processes use a one-time blowing and direct exhaust gas emission mode, with a triethylamine utilization rate of only 10%-20%. A large amount of amine gas is emitted with the exhaust gas, which not only consumes a lot of raw materials and has high costs, but also causes serious VOCs pollution, endangering human health. Conventional exhaust gas washing and neutralization methods only convert gaseous pollution into hazardous waste, which is a temporary solution and has high operating costs and a high risk of secondary pollution.

[0003] Triethylamine acts only as a catalyst in the reaction and does not participate in the final polymerization. The amine gas in the tail gas remains active, providing a theoretical basis for closed-loop recycling. Therefore, developing a high-efficiency, low-cost, and compatible closed-loop triethylamine core-making process and equipment to achieve high utilization, near-zero emissions, and stable core performance has become an urgent need for the industry's green upgrading and cost reduction and efficiency improvement. Summary of the Invention

[0004] To address the problems mentioned in the background section, this invention provides a triethylamine recycling system and method for cold box core shooting production.

[0005] The technical solution of this invention is as follows: A triethylamine circulation system for cold box core shooting production includes a triethylamine supply system for supplying high-purity triethylamine during the core shooting process. The amine supply pipeline is connected to the outlet of the triethylamine supply system, and the outlet of the amine supply pipeline is connected to the core injection system. An exhaust gas recovery system for recovering and filtering exhaust gas mixed with triethylamine gas that has undergone a catalytic reaction includes a filter bladder placed inside a recovery cylinder, the recovery cylinder having rigidity to maintain internal space that limits the expansion stroke of the filter bladder. The exhaust gas recovery pipe is used to connect the core injection system and the exhaust gas recovery system. One end of the pipe is connected to the exhaust port of the core injection system, and the other end passes through the recovery cylinder and is connected to the filter bag. The gas storage tank has an inlet connected to the filter bag and an outlet connected to the end of the amine supply pipeline away from the core injection system. The valve system includes a proportional gas valve for controlling the pressure of triethylamine gas entering the core ejection system, which is installed on the amine supply pipeline, and a programmable shut-off valve installed on the waste gas recovery pipeline for controlling the flow rate and on / off of the recovered tail gas.

[0006] The triethylamine supply system is specifically designed as follows: the triethylamine supply system includes a raw liquid tank, which is connected to the amine supply pipeline through a high-precision metering pump, and a triethylamine vaporizer is also installed on the amine supply pipeline between the system and the core injection system.

[0007] In order to stabilize and control the pressure of triethylamine after mixing, ensure the pressure entering the triethylamine vaporizer is stable, and thus provide a guarantee for the hardening reaction during the core shooting process, and avoid pressure fluctuations affecting the sand core forming quality, the blowing proportional valve is installed on the gas supply pipeline between the gas storage tank and the high-precision metering pump.

[0008] In order to prevent the gas storage tank from being damaged by external impacts and to recover triethylamine that is accidentally leaked from the gas storage tank, thereby greatly reducing the probability of toxic and harmful gases directly spreading into the production environment and ensuring the safety of operations at the production site, the gas storage tank is placed inside a protective cylinder, which is located below and supports the recovery cylinder.

[0009] The exhaust gas filter is specifically designed such that a vent pipe is provided inside the filter airbag, and the vent pipe is connected to the inner cavity of the filter airbag through several vent holes opened in the side wall. A filter screen is installed at the vent holes, and one end of the vent pipe is connected to the air storage tank.

[0010] To facilitate on-site installation of the filter airbag and recovery cylinder, the vent pipe is designed to pass through both ends of the filter airbag and recovery cylinder, and connecting frames are provided near both ends of the vent pipe to suspend the filter airbag and recovery cylinder.

[0011] In order to further filter residual dust and impurities in the exhaust gas and prevent impurities from entering the gas storage tank and contaminating the recovered triethylamine gas, and at the same time pressurize the filtered triethylamine gas through a gas compressor to ensure its stable storage in the gas storage tank and meet the pressure requirements of subsequent gas circulation supply, thus ensuring a stable gas supply process, a gas compressor is installed between the vent pipe and the gas storage tank. The inlet and outlet of the gas compressor are connected to the vent pipe and the gas storage tank, respectively, and a secondary filter is installed between the compressor and the vent pipe.

[0012] A triethylamine recycling method for cold box core shooting production, which applies the aforementioned triethylamine recycling system, includes the following steps: S1: Start the triethylamine supply system to vaporize liquid triethylamine into fresh amine gas, which is then transported to the core injection system through the amine supply pipeline. After the hardening reaction is completed, the shaped sand core is obtained. S2: Start the programmable shut-off valve. The exhaust gas mixed with residual triethylamine is passed through the waste gas recovery pipe into the filter bag in the recovery cylinder. The filtered triethylamine gas is stored in the storage tank. S3: Once the pressure in the gas storage tank reaches the preset value, open the gas storage tank and the blowing ratio valve, and close the triethylamine supply system. The recovered triethylamine is then transported to the core ejector system through the amine supply pipeline at a predetermined pressure to participate in the reaction. S4: Until the concentration of recovered triethylamine gas is detected to be lower than the preset value, start the triethylamine supply system to replenish fresh high-purity triethylamine, maintain the concentration of triethylamine gas entering the core shooting system, and repeat the above recovery cycle process until the predetermined number of sand cores are prepared.

[0013] In order to provide a pressure carrier for the flow of triethylamine gas, the gas storage tank and the triethylamine supply system are connected to a nitrogen source through a nitrogen supply pipeline, which provides a stable pressure carrier for the triethylamine gas after startup.

[0014] In order to cut off the gas supply to the gas storage tank during the fresh triethylamine gas supply stage, prevent high-pressure fresh amine gas from flowing back into the gas storage tank and causing pressure disturbances, and ensure stable gas pressure in each branch during the circulation process, a switch valve is installed near the amine supply pipeline of the gas storage tank, which can control the output of recovered triethylamine in step S3.

[0015] The beneficial effects of this invention are as follows: This invention provides a triethylamine recycling system and method for cold box core shooting production. It effectively improves upon the technical shortcomings of traditional cold box core making processes, such as low triethylamine utilization, high raw material consumption, severe VOC emissions, and secondary pollution and high operating costs associated with conventional tail gas treatment methods. Utilizing the characteristic that triethylamine only acts as a catalyst and does not participate in the polymerization reaction, and that the tail gas amine gas is recyclable, a closed-loop gas recovery and recycling system is constructed, significantly improving the reuse rate of triethylamine raw materials and significantly reducing the raw material procurement costs for enterprises. Compared to traditional direct tail gas discharge, washing and neutralization, and conventional adsorption and condensation recovery methods, this system does not require the conversion of gaseous pollutants into hazardous waste for treatment, effectively reducing the operation and maintenance investment and secondary pollution risks associated with hazardous waste disposal. It also avoids the drawbacks of traditional recycling equipment, such as poor adaptability, easy interference with sand core forming quality, high investment costs for mature foreign equipment, and difficulty in modification. It can be adapted to the upgrading of existing cold box core shooting equipment, has strong versatility, and can meet the development needs of the foundry industry for green and environmentally friendly production and cost reduction and efficiency improvement while ensuring sand core forming accuracy and production efficiency. Attached Figure Description

[0016] 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.

[0017] In the attached diagram: Figure 1 This is a first schematic diagram of the structure of the present invention; Figure 2This is a second schematic diagram of the structure of the present invention; Figure 3 This is a schematic diagram of the vent pipe installation; Figure 4 This is a schematic diagram of the core-shooting system; Figure 5 for Figure 4 Enlarged view of a portion of point A in the middle.

[0018] The components represented by the various reference numerals in the diagram are: 1. Triethylamine supply system; 101. Raw material tank; 102. High-precision metering pump; 2. Amine supply pipeline; 3. Core injection system; 301. Core injection head; 302. Mold; 303. Mandrel; 304. Lifting seat; 305. Gas chamber; 306. Forming cavity; 307. First vent; 308. Second vent; 309. First annular groove; 310. Gas collecting plate; 311. Second annular groove; 4. Tail gas recovery system; 401. Filter bag ; 402. Recovery cylinder; 403. Vent pipe; 404. Vent hole; 405. Connecting frame; 5. Waste gas recovery pipeline; 6. Gas storage tank; 7. Valve system; 701. Air blowing proportional valve; 702. Programmable shut-off valve; 703. Switch valve; 8. Triethylamine vaporizer; 9. Protective cylinder; 10. Gas compressor; 11. Gas outlet pipe; 12. Secondary filter; 13. Nitrogen source; 14. Pressure monitoring device; 15. Concentration detector; 16. Sand core. 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 This embodiment discloses a triethylamine recycling system and method for cold box core production, suitable for triethylamine cold box core-making production lines for precision castings such as automobiles, construction machinery, and cast pipes. Existing traditional cold box core-making processes employ a one-time blowing and direct exhaust gas emission mode, resulting in a triethylamine utilization rate of only 10% to 20%. This leads to high raw material consumption, high production and operating costs, and direct exhaust gas emission generating large amounts of VOCs pollutants, which not only harm the health of on-site workers but also fail to meet increasingly stringent environmental control requirements. Conventional exhaust gas washing and neutralization processes only achieve pollutant form conversion, transforming gaseous pollution into hazardous waste, which is only a temporary solution and still presents high operating costs and secondary pollution risks. Furthermore, existing adsorption methods in China... Condensation-based recovery equipment suffers from low recovery efficiency and poor equipment adaptability, easily interfering with the quality of sand core molding. Mature foreign recovery equipment has high investment costs, weak equipment versatility, and is difficult to modify on-site, failing to address the industry pain points of widespread adoption and modification of domestic production lines. This paper addresses these issues by leveraging the characteristics of triethylamine, which acts only as a catalyst medium, does not participate in the polymerization reaction, and retains reactivity in residual amine gas in the tail gas. A closed-loop recycling system is constructed, featuring filtration recovery, pressure stabilization storage, and closed-loop reuse. This significantly improves the utilization rate of triethylamine raw materials, substantially reduces tail gas pollutant emissions, effectively reduces hazardous waste generation and raw material consumption, and is compatible with existing cold core firing equipment. The system requires low modification investment, provides stable sand core molding performance, and meets the dual production needs of enterprises for cost reduction, efficiency improvement, and green environmental protection upgrades.

[0021] In this embodiment, combined with Figure 1 and Figure 2 The first system disclosed is the triethylamine circulation system used in the core shooting process. This system includes a triethylamine supply system 1, an amine supply pipeline 2, a tail gas recovery system 4, a waste gas recovery pipeline 5, a gas storage tank 6, and a valve system 7. These systems work together to form a complete closed-loop circulation path, operating in a fully sealed manner to significantly reduce amine gas leakage. The overall structure is compatible with the conventional cold-box core shooting production cycle and will not adversely affect the original core shooting process, core precision, or curing effect. The triethylamine supply system 1 serves as a fresh raw material supply unit, stably supplying high-purity vaporized triethylamine to the core shooting system 3 to meet the basic requirements of the core hardening catalytic reaction. The triethylamine supply system 1 includes a raw material tank 101, which stores liquid high-purity triethylamine raw material. The outlet of the raw material tank 101 is connected to a high-precision metering pump 102 via a pipeline. The high-precision metering pump 102 can accurately control the flow rate of liquid triethylamine, ensuring a stable vaporization concentration. The output of the high-precision metering pump 102 is connected to the amine supply pipeline 2 to achieve quantitative feeding. A triethylamine vaporizer 8 is installed on the amine supply pipeline 2 between the raw liquid tank 101 and the core shooting system 3. Liquid triethylamine is quantitatively delivered to the triethylamine vaporizer 8 via a high-precision metering pump 102. Through constant temperature vaporization, uniform and stable gaseous triethylamine is formed, avoiding the problem of uneven local reaction and sand core defects caused by the direct entry of liquid raw materials into the core shooting system 3, thus ensuring the stability of the hardening reaction.

[0022] Based on the above system, the amine supply pipeline 2 serves as the core channel for amine gas transportation. One end is connected to the outlet of the triethylamine supply system 1, which is connected to the back end of the high-precision metering pump 102. The other end is directly connected to the gas inlet of the core shooting system 3. It is used to stably transport fresh gasified triethylamine or recovered and purified triethylamine gas to the core shooting system 3 to complete the sand core catalytic hardening reaction. Valve system 7 is used to regulate the on / off state, pressure, and flow parameters of the entire circulating gas path throughout the process, ensuring the stability and controllability of the system operation. It includes two types of control valves: a blowing proportional valve 701 and a programmable shut-off valve 702. The blowing proportional valve 701 is installed on the gas supply pipeline between the gas storage tank 6 and the high-precision metering pump 102. It can accurately regulate the pressure and flow of triethylamine gas entering the core shooting system 3 in real time, adapting to the hardening blowing requirements of sand cores of different specifications. It avoids the problem of gas waste caused by excessive pressure and incomplete hardening caused by excessive pressure. The programmable shut-off valve 702 is installed on the waste gas recovery pipeline 5. It is used to accurately control the on / off state and recovery flow of the tail gas recovery pipeline, matching the core shooting process rhythm. The recovery process is only started after the hardening reaction is completed, effectively reducing the occurrence of cross-flow and leakage during the production process.

[0023] Combination Figure 1 and Figure 3 The exhaust gas recovery system 4, as the core unit for residual amine gas recovery, filtration, and purification, is used to recover and filter the production exhaust gas mixed with residual triethylamine after catalytic reaction. It removes sand, dust, impurities, and excess water vapor from the exhaust gas, retaining the catalytically active triethylamine gas for resource recovery and reuse. Its core components include a recovery cylinder 402 and a built-in filter bladder 401. The recovery cylinder 402 is made of high-strength, rigid metal, with high overall structural strength, capable of stably maintaining its internal shape. It can reasonably limit the inflation stroke of the internal filter bladder 401, preventing excessive expansion, deformation, and damage, while also avoiding structural deformation caused by excessive negative pressure contraction, ensuring long-term continuous operational stability. One end of the exhaust gas recovery pipe 5 connects to the exhaust port of the core ejector system 3, and the other end extends into the recovery cylinder 402 and connects to the filter bladder 401. The mixed exhaust gas after the hardening reaction is completed can be precisely introduced into the filter bladder 401 through the exhaust gas recovery pipe 5 for initial sealed collection.

[0024] It should be noted that, in combination Figures 3-5This technology changes the traditional open gas path structure of cold box core making, which uses "top amine blowing - bottom direct discharge". Instead, it uses a reverse airflow method where amine is fed from the bottom of the core shooting system 3. During the core making process, the amine diffuses evenly through the gas channel in the middle of the core, and is collected and recovered from the top via the waste gas recovery pipe 5. Specifically, the core shooting system 3 includes a core box system with a core shooting head 301 on top. The core box system includes two openable semi-circular molds 302, with a hollow mandrel 303 between them. A lifting seat 304 is located at the bottom of the mandrel 303 to facilitate demolding after molding. 04 An internal gas chamber 305 is set up, forming a molding cavity 306 between the mandrel 303 and the mold 302. The upper end of the amine supply pipe 2 in this solution is connected to the gas chamber 305 of the lifting seat 304, thus forming a bottom amine supply form. The amine gas can be evenly seeped out from the surface of the mandrel 303 and gradually fill the entire molding cavity 306. Compared with the traditional top blowing, it is easier to ensure that the amine gas distribution in the entire cavity is uniform and there will be no local concentration that is too high or too low. For large-size sand cores, it can effectively improve the overall hardening uniformity and reduce the problem of sand core scrap caused by under-hardening and uneven hardening.

[0025] This solution also features an innovative design for the gas channel during the amine curing process, incorporating... Figure 4 and Figure 5 The gas chamber 305 is part of the gas channel. Its upper end is connected to the inner cavity of the core rod 303. The core rod 303 has a first vent 307 arranged in a layered circumferential array near the bottom. This allows amine gas to participate in the curing of the sand core from multiple directions through the gas chamber 305 and the first vent 307, ensuring synchronous curing inside and outside and reducing the curing dead corners of the sand core. Secondly, the two molds 302 have a second vent 308 arranged in a circumferential array on the side near the upper end. This is arranged above and below the first vent 307, allowing the amine gas to flow from bottom to top during the reaction. In addition, the two molds 302 have a first annular groove 309 that is connected to each other on the upper surface. The second vent 308 is connected to the first annular groove 309, thus forming a gas channel in which the amine gas flows from bottom to top in the middle of the sand core during the core making process.

[0026] Based on the above structure, a gas collecting plate 310 that can fit against the upper surface of the mold 302 is provided, and the gas collecting plate 310 is equipped with an induced draft fan as the power source for waste gas recovery. The gas collecting plate 310 has a cavity structure and a second annular groove 311 is opened at the bottom. When the gas collecting plate 310 fits against the mold 302, the second annular groove 311 fits against and connects with the first annular groove 309. The upper end of the waste gas recovery pipe 5 is connected to the upper end of the gas collecting plate 310. Through the first annular groove, the second annular groove 311, and the cavity of the gas collecting plate 310, the waste gas recovery pipe 5 can achieve the following: After solidification, the exhaust gas flows into the waste gas recovery pipe 5, completing the reverse airflow method of centralized recovery at the top. At the same time, the reverse airflow can gradually squeeze the air originally left in the cavity upward, and finally enter the waste gas recovery pipe 5 at the top with the residual amine gas. This avoids the residual air diluting the amine gas concentration and affecting the hardening efficiency. Through closed-loop circulation, triethylamine can be added once and reused multiple times. This fundamentally solves the problems of low amine gas utilization and large direct discharge loss in traditional processes, and achieves uniform distribution of amine gas and efficient tail-end convergence and recovery.

[0027] In addition, a vent pipe 403 is centrally mounted inside the filter bag 401. Several vent holes 404 are evenly distributed on the wall of the vent pipe 403. The vent holes 404 serve as gas flow channels, allowing the inner cavity of the filter bag 401 to communicate with the inside of the vent pipe 403. Each vent hole 404 is equipped with a precision filter structure. A filter element is installed inside the vent pipe 403 for further filtration, which can protect the piston seal ring and steel sleeve of the gas compressor. It can effectively intercept solid pollutants such as molding sand dust and solidified impurities carried in the exhaust gas, achieve fine filtration and purification of amine gas, and prevent impurities from entering the subsequent gas storage tank 6 and pipelines, causing blockage and pollution, and ensuring the purity of the circulating gas. The vent pipe 403 adopts a through-type structure at both ends, with the two ends respectively penetrating the outer walls of the filter bag 401 and the recovery cylinder 402. The through-type positions are mechanically sealed. The vent pipe 403 is fixedly equipped with a connecting frame 405 near both ends. The connecting frame 405 adopts a suspension structure design, which can simultaneously realize the suspension and fixed installation of the filter bag 401 and the recovery cylinder 402. The assembly structure is simple and stable, and the disassembly and maintenance are convenient, which can effectively reduce the difficulty of equipment maintenance.

[0028] Based on the above structure, a secondary filter 12 and a gas compressor 10 are sequentially assembled between the output end of the vent pipe 403 and the air intake end of the gas storage tank 6. The secondary filter 12 can perform secondary deep purification on the triethylamine gas after primary filtration, further remove fine dust and trace impurities, greatly improve the purity of the recovered gas, and avoid the accumulation of impurities during long-term cyclic use that affects the quality of the sand core. The air inlet of the gas compressor 10 is connected to the air outlet end of the secondary filter 12, and the air outlet end is communicated with the air inlet of the gas storage tank 6 through an air outlet pipe 11. The gas compressor 10 can perform voltage stabilization and pressurization treatment on the purified triethylamine gas, compress and store the low-pressure recovered gas inside the gas storage tank 6. The gas compressor 10 pressurizes the purified low-pressure tail gas to 0.28Mpa-0.32Mpa and stores it in the gas storage tank 6, ensuring stable gas pressure in the gas storage tank 6 and providing a stable power foundation for subsequent cyclic gas supply. The gas storage tank 6 serves as a voltage-stabilizing storage unit for recovered gas, its air intake end is communicated with the vent pipe 403 of the filter airbag 401, and its air outlet end is connected to the end of the amine supply pipe 2 away from the core shooting system 3, so that the recovered and purified triethylamine gas can be reintroduced into the amine supply pipe 2 to realize closed-loop cyclic reuse. The entire gas storage tank 6 is arranged inside the protective cylinder 9, and the protective cylinder 9 is fixedly installed at the position below the recovery cylinder 402. It can form stable support for the upper recovery cylinder 402, and at the same time play a dust-proof, anti-collision and protective role for the gas storage tank 6, improving the overall operation safety and structural stability of the equipment. An independent switch valve 703 is also installed on the amine supply pipe 2 near the gas storage tank 6, which can independently control the on-off of the output of the recovered triethylamine gas, realize the switching gas supply control between fresh amine gas and recovered amine gas, and adapt to the needs of different production working conditions.

[0029] The triethylamine circulation method matched with this system is a proprietary process method adapted to the above circulation system, which can realize automatic circulation recovery, gas supply switching and pipeline purging. The overall steps are coherent and fit the automatic rhythm of the production line. The specific operation is executed by the control system as follows: First, step S1 is executed. After the equipment is started, the triethylamine supply system 1 starts to work first. The liquid triethylamine inside the raw liquid tank 101 is quantitatively delivered to the triethylamine gasifier 8 via a high-precision metering pump 102 to complete constant-temperature gasification, generating high-purity fresh triethylamine gas. The fresh amine gas is stably delivered into the core shooting system 3 through the amine supply pipe 2, and participates in the catalytic hardening reaction of the cold core sand core. After the reaction is completed, a formed sand core with stable structure and qualified dimensional accuracy is obtained, and a single core shooting hardening process is completed.

[0030] Then, step S2 is executed. After a preset reaction time, the programmable shut-off valve 702 on the waste gas recovery pipeline 5 is opened. The mixed exhaust gas containing triethylamine remaining inside the core firing system 3 is introduced into the filter bladder 401 inside the recovery cylinder 402 through the waste gas recovery pipeline 5 in a closed manner. The rigid recovery cylinder 402 limits the expansion range of the bladder to ensure that the exhaust gas is evenly filled inside the bladder. The exhaust gas undergoes preliminary filtration through the bladder filter screen and the ventilation hole 404 of the ventilation pipe 403 to remove most of the sand and dust impurities. Then it undergoes deep purification through the secondary filter 12 and is pressurized by the gas compressor 10. Finally, the purified triethylamine gas is transported and stored inside the gas storage tank 6 to complete the exhaust gas recovery and storage process. The entire process is closed and leak-free, which greatly reduces VOC emissions.

[0031] It should be noted that this scheme forms a "bottom amine supply - top exhaust gas recovery" method through the design of the core injection system 3 and the gas channel. In step S1, the vaporized amine gas enters the gas chamber 305 of the lifting seat 304 through the amine supply pipe 2, and participates in the solidification of the sand core from bottom to top through the gas channel. The exhaust gas is recovered to the gas collection plate 310. In step S2, the exhaust gas in the gas collection plate 310 is recovered to the filter air bag 401 through the waste gas recovery pipe 5.

[0032] Next, step S3 is executed, and the internal pressure parameters of the gas storage tank 6 are monitored in real time. After the pressure inside the tank reaches the preset working pressure value of the system, in actual working conditions, after 5-6 sand cores have been prepared, the gas outlet valve 703 of the gas storage tank 6 and the blowing proportion valve 701 on the amine supply pipeline 2 are opened. At the same time, the triethylamine supply system 1 is temporarily closed to stop the supply of fresh amine gas. The output gas pressure is precisely controlled by the blowing proportion valve 701, and the triethylamine gas recovered and purified inside the gas storage tank 6 is delivered to the core injection system 3 at a preset stable pressure to replace the fresh raw material in the next round of sand core hardening catalytic reaction. This fully utilizes the active triethylamine component in the tail gas and effectively reduces raw material consumption.

[0033] Moreover, combined Figure 2 The gas storage tank 6 is connected to a pressure monitoring device 14, which is used to monitor the amine gas pressure in the gas storage tank 6 in real time. When the preset pressure is reached in step S3, the gas storage tank 6 supplies gas to the amine supply pipeline 2. In this scheme, in step S3, by setting a PLC control system, the gas storage tank 6 can be controlled to adjust the gas supply according to the core firing cycle of the core firing system 3. The actual amine supply flow rate of the gas storage tank 6 is Q, Q=K*Q0*P t / P set Where Q0 is the base flow rate corresponding to different core firing cycles, and P t The actual pressure monitored by gas storage tank 6, P setThe preset pressure value reached by the triethylamine gas in the gas storage tank 6, K is the opening coefficient of the blowing proportional valve 701, with a value of 0-1, and the base flow rate corresponding to different core firing cycles is different, Q0=60*C*V 芯 / t 吹 Where C is the desired target triethylamine concentration, and V 芯 For the volume of the sand core cavity, t 吹 The actual blowing and solidification time within one cycle is linearly related to the total core-shooting cycle period T, where t 吹 =α*T, where α is the blowing ratio coefficient, which is 0.1-0.25.

[0034] In addition, the real-time pressure in the gas storage tank 6 is controlled by the gas compressor 10, when P t When the pressure is ≤0.28MPa, gas compressor 10 starts to compensate for pressure, at P t When the pressure is ≥0.32 MPa, gas compressor 10 is shut down, and the compressor pressure replenishment follows Q. out =Q in *η, where Q out Q is the compressor's intake airflow rate. in η is the compressor's output flow rate, and η is the compressor efficiency.

[0035] Finally, in step S4, the system monitors the triethylamine gas concentration in real time during the circulating gas supply process. When the recovered gas concentration is detected to be lower than the preset working concentration and unable to meet the requirements of the sand core hardening process, the triethylamine supply system 1 is automatically restarted to replenish fresh high-purity triethylamine gas into the circulation pipeline, maintaining the concentration and stability of amine gas entering the core shooting system 3 in real time, ensuring that the sand core forming quality always meets the standards. The closed-loop process of recovery, gas storage, circulating gas supply, and material replenishment is continuously repeated until the batch preparation of the preset number of sand cores is completed. Specifically, the filter bag 401 is equipped with a triethylamine concentration detector 15, which is electrically connected to the control system. When the triethylamine supply system 1 needs to be replenished, the replenishment amount Mreplenish = (CCreplenish)replenish. 实 )*V 囊 *ρ / (β*100), the control system controls the high-precision metering pump 102 to replenish the amine supply pipeline 2 according to the replenishment amount, where C is the required target triethylamine concentration, C is the triethylamine concentration monitored in real time, V 囊 ρ is the effective volume of the filter airbag 401, ρ is the concentration of liquid triethylamine in the raw liquid tank 101, and β is the vaporization efficiency of the triethylamine vaporizer 8.

[0036] After all the sand core preparation processes are completed, the nitrogen source 13, which is connected to the amine supply pipeline 2 between the gas storage tank 6 and the triethylamine supply system 1, is started. After step S1 begins, the nitrogen source 13 is started to provide nitrogen with a certain pressure to the amine supply pipeline 2 as a carrier of triethylamine gas, thereby improving the uniformity and flow stability of the triethylamine gas. At the same time, nitrogen is an inert gas and will not participate in the catalytic reaction, so it will not interfere with the sand core forming process.

Claims

1. A triethylamine recycling system for cold box core shooting production, characterized in that, include: Triethylamine supply system (1), which is used to supply high-purity triethylamine during the core shooting process; The amine supply pipeline (2) is connected to the outlet of the triethylamine supply system (1), and the outlet of the amine supply pipeline (2) is connected to the core firing system (3). The core-shooting system (3) includes a core box system with a core-shooting head (301) on top. The core box system includes two openable semi-annular molds (302) with hollow core rods (303) inside. A lifting seat (304) is provided at the bottom of the core rod (303). A gas chamber (305) is provided inside the lifting seat (304). The upper end of the amine supply pipe (2) is connected to the gas chamber (305) of the lifting seat (304). The upper end of the gas chamber (305) is connected to the inner cavity of the core rod (303). The core rod (303) has a first air hole (307) arranged in a circumferential array near the bottom. The two molds (302) have a second air hole (308) arranged in a circumferential array on the side near the upper end. The two molds (302) have a first annular groove (309) that is connected to each other on the upper surface of the two molds (302). The second air hole (308) is connected to the first annular groove (309). A gas collecting plate (310) that can fit against the upper surface of the mold (302) is provided, and the gas collecting plate (310) is equipped with an induced draft fan as the power source for waste gas recovery. The upper end of the waste gas recovery pipe (5) is connected to the upper end of the gas collecting plate (310). A second annular groove (311) is opened at the bottom of the gas collecting plate (310). The second annular groove (311) fits against and connects with the first annular groove (309). The exhaust gas recovery system (4) is used to recover and filter exhaust gas mixed with triethylamine gas that has undergone catalytic reaction, including a filter bag (401) placed inside a recovery cylinder (402), which has rigidity to maintain the internal space to limit the expansion stroke of the filter bag (401). The exhaust gas recovery pipe (5) is used to connect the core ejection system (3) and the exhaust gas recovery system (4). One end of the pipe is connected to the exhaust port of the core ejection system (3), and the other end passes through the recovery cylinder (402) and is connected to the filter bag (401). The gas storage tank (6) has its inlet connected to the filter bag (401) and its outlet connected to the end of the amine supply pipeline (2) away from the core injection system (3); The valve system (7) includes a blowing proportional valve (701) for controlling the pressure of triethylamine gas entering the core injection system (3), which is installed on the amine supply pipeline (2), and also includes a programmable shut-off valve (702) installed on the waste gas recovery pipeline (5) for controlling the flow rate and on / off of the recovered tail gas.

2. The triethylamine recycling system for cold box core shooting production according to claim 1, characterized in that, The triethylamine supply system (1) includes a raw liquid tank (101), which is connected to the amine supply pipeline (2) via a high-precision metering pump (102), and a triethylamine vaporizer (8) is also installed on the amine supply pipeline (2) between the core injection system (3).

3. A triethylamine recycling system for cold box core shooting production according to claim 2, characterized in that, The air blowing proportional valve (701) is installed on the air supply pipeline between the air storage tank (6) and the high-precision metering pump (102).

4. A triethylamine recycling system for cold box core shooting production according to claim 1, characterized in that, The gas storage tank (6) is placed inside the protective cylinder (9), and the protective cylinder (9) is located below and supports the recovery cylinder (402).

5. A triethylamine recycling system for cold box core shooting production according to claim 1, characterized in that, The filter airbag (401) is provided with a vent pipe (403), and the vent pipe (403) is connected to the inner cavity of the filter airbag (401) through a number of vent holes (404) opened on the side wall. A filter screen is installed at the vent hole (404), and one end of the vent pipe (403) is connected to the air storage tank (6).

6. A triethylamine recycling system for cold box core shooting production according to claim 5, characterized in that, The ventilation pipe (403) is designed to pass through the filter air bag (401) and the recovery cylinder (402) at both ends, and a connecting frame (405) is provided near both ends of the ventilation pipe (403), which can suspend and install the filter air bag (401) and the recovery cylinder (402).

7. A triethylamine recycling system for cold box core shooting production according to claim 5, characterized in that, A gas compressor (10) is provided between the vent pipe (403) and the gas storage tank (6), and the inlet and outlet of the gas compressor (10) are connected to the vent pipe (403) and the gas storage tank (6) respectively, and a secondary filter (12) is provided between the gas compressor (403) and the vent pipe (403).

8. A triethylamine recycling method for cold box core shooting production, wherein the method utilizes the triethylamine recycling system as described in any one of claims 1-7, characterized in that, Includes the following steps: S1: Start the triethylamine supply system (1), vaporize the liquid triethylamine to form fresh amine gas and transport it to the core shooting system (3) through the amine supply pipeline (2). After the hardening reaction is completed, the molded sand core (16) is obtained. S2: Start the programmable shut-off valve (702), and the tail gas mixed with residual triethylamine is passed through the waste gas recovery pipe (5) into the filter bag (401) in the recovery cylinder (402). The filtered triethylamine gas is stored in the gas storage tank (6). S3: When the pressure in the gas storage tank (6) reaches the preset value, open the gas storage tank (6) and the blowing ratio valve (701), and close the triethylamine supply system (1). The recovered triethylamine is then transported to the core ejection system (3) through the amine supply pipeline (2) at a predetermined pressure to participate in the reaction. S4: Until the concentration of recovered triethylamine gas is detected to be lower than the preset value, start the triethylamine supply system (1) to replenish fresh high-purity triethylamine, maintain the concentration of triethylamine gas entering the core shooting system (3), and repeat the above recovery cycle process until the preparation of the predetermined number of sand cores (16) is completed.

9. A triethylamine recycling method for cold box core shooting production according to claim 8, characterized in that, The gas storage tank (6) and the triethylamine supply system (1) are connected by a nitrogen source (13) through the amine supply pipeline (2), which provides a stable pressure carrier for the triethylamine gas after it is started.

10. A triethylamine recycling method for cold box core shooting production according to claim 8, characterized in that, A switch valve (703) is installed near the amine supply pipeline (2) of the gas storage tank (6), which can control the output of triethylamine recovery in step S3.

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