Continuous production device for 1, 5-naphthalene diisocyanate

Abstract

The utility model relates to the technical field of chemical equipment, in particular to a 1, 5-naphthalene diisocyanate continuous production device which comprises a mixing tank, a first cold reaction kettle, a second cold reaction kettle, a middle kettle, a first thermal reaction kettle, a second thermal reaction kettle, a third thermal reaction kettle, a temporary storage kettle, a filter, a film evaporator and a material receiving tank which are communicated in sequence, the mixing tank is respectively communicated with a first dissolving kettle and a second dissolving kettle; the first cold reaction kettle and the middle kettle are also communicated to a waste gas buffer tank; the temporary storage kettle is connected to a first condenser, and the first condenser is further connected to a waste gas buffer tank; a gas outlet of the film evaporator is communicated to a solvent receiving tank through a pipeline and a cooler, the solvent receiving tank is connected to a second condenser, the second condenser is further connected to a vacuum buffer tank, and the vacuum buffer tank is connected to a vacuum generator. The device is simple in production process, is matched with an automatic control system for operation, can realize continuous production, effectively reduces the labor intensity, and improves the working efficiency.

Description

Technical Field

[0001] This utility model relates to the field of chemical equipment technology, and in particular to a continuous production apparatus for 1,5-naphthalene diisocyanate. Background Technology

[0002] 1,5-Naphthalene diisocyanate (NDI) is a high-performance isocyanate. Polyurethanes synthesized from 1,5-naphthalene diisocyanate have excellent properties such as high strength, high deformation stability, high abrasion resistance, high tear strength and high elasticity, so the demand for it is increasing. Currently, the preparation methods for 1,5-naphthalene diisocyanate include phosgene and non-phosgene synthesis routes. The non-phosgene method is safe and environmentally friendly, but it cannot be implemented in actual production at present due to production cost issues. The phosgene method includes gaseous phosgene and solid phosgene. The use of gaseous phosgene requires on-site production of phosgene, and the raw materials contain chlorine, which is relatively dangerous. The solid phosgene method uses solid phosgene that is stable at room temperature and pressure. Traditional phosgene methods all adopt batch production processes, which mainly include crude product synthesis (dissolution, cold reaction, hot reaction, filtration concentration, crystallization centrifugation, etc.) and distillation purification. The synthesis process has disadvantages such as long reaction time (long hot reaction time), complex operation, and small production capacity of a single reactor, resulting in low equipment utilization, low yield, and unstable product quality. Therefore, it is necessary to overcome the above problems in actual production. Utility Model Content

[0003] The technical problem to be solved by this utility model is to provide a continuous production device for 1,5-naphthalene diisocyanate, which addresses the shortcomings of the existing technology. The production process is simple, and with the help of an automatic control system, continuous production can be achieved, effectively reducing labor intensity and improving work efficiency.

[0004] To solve the above-mentioned technical problems, the technical solution of this utility model is as follows:

[0005] A continuous production apparatus for 1,5-naphthalene diisocyanate includes a mixing tank, a first cold reaction vessel, a second cold reaction vessel, an intermediate vessel, a first hot reaction vessel, a second hot reaction vessel, a third hot reaction vessel, a temporary storage vessel, a filter, a thin-film evaporator, and a material receiving tank, which are connected sequentially by pipes, valves, and pumps. The mixing tank is connected to a first dissolving vessel and a second dissolving vessel via pipes and flow meters. Both the first cold reaction vessel and the intermediate vessel are equipped with exhaust ports and sludge discharge ports (for emergency response). The exhaust ports are connected to a waste gas buffer tank via pipes. The lower part of the temporary storage vessel is equipped with a nitrogen input pipe (nitrogen is used to purge the feed pipe and filter) and a discharge pipe. The upper part of the temporary storage vessel is equipped with a nitrogen pressurization pipe (nitrogen is used for filter pressurization assistance and to purge the vessel) and a gas output pipe (considered as a distillation column, its function is to distill the gaseous state in the vessel). Solvent evaporates and rises into the first condenser. The gas output pipe is connected to the first condenser. The lower part of the first condenser is also equipped with a U-shaped reflux pipe connected to the temporary storage tank (after condensation, it enters the lower U-shaped reflux pipe and flows back into the temporary storage tank; a small amount of uncondensed solvent enters the waste gas buffer tank for collection and recovery through a pipeline). The first condenser is connected to the waste gas buffer tank through a pipeline. The gas outlet of the thin film evaporator is connected to the solvent receiving tank through a pipeline and a cooler. The gas outlet of the solvent receiving tank is connected to the second condenser through a gas output pipe and a U-shaped reflux pipe. The second condenser is also connected to the vacuum buffer tank through a pipeline. The vacuum buffer tank is connected to the vacuum generator through a pipeline. Valves, flow meters, filters, thin film evaporators, first condensers, second condensers, and pumps are all electrically connected to the automatic control system.

[0006] Preferably, the mixing tank, the first dissolving vessel, the second dissolving vessel, the first cold reaction vessel, the intermediate vessel, and the temporary storage vessel are all equipped with stirring devices. All stirring devices are electrically connected to the automatic control system.

[0007] Preferably, the second cold reactor, the first hot reactor, the second hot reactor, and the third hot reactor are all equipped with heat-insulating jackets. Each reactor contains a pipeline-type feed pipe and a temperature sensor. The feed pipe is formed by connecting several vertically arranged vertical pipes with elbows, and the outside of the pipe is the heat exchange medium. The heat exchange medium in the second cold reactor is cold brine, the heat exchange medium in the first and second hot reactors is hot water, and the heat exchange medium in the third hot reactor is steam. The temperature sensor is electrically connected to the automatic control system.

[0008] Preferably, the mixing tank, the first dissolving vessel, the second dissolving vessel, the first cold reaction vessel, the intermediate vessel, and the temporary storage vessel are all equipped with temperature control jackets and temperature sensors. Each temperature control jacket is equipped with a heat exchange medium input system and a heat exchange medium collection system, and the heat exchange medium input system, the heat exchange medium collection system, and the temperature sensors are all electrically connected to the automatic control system.

[0009] Preferably, two of each of the first and second dissolving vessels are provided. One of them is kept as a spare to ensure continuous material supply during production.

[0010] Preferably, the feed pumps between the first and second cold reactors, and between the intermediate reactor and the first reactor, are all plunger pumps.

[0011] Preferably, four temporary storage vessels are connected in parallel.

[0012] Preferably, the nitrogen input pipe of the temporary storage vessel is connected to a nitrogen supply system. The nitrogen supply system is electrically connected to an automatic control system.

[0013] Preferably, the filter is model WKZ-7 and manufactured by Weikong Filtration Technology (Suzhou) Co., Ltd.; the membrane evaporator is model GZX-2 and manufactured by Wuxi Lima Chemical Machinery Co., Ltd.

[0014] Preferably, the waste gas buffer tank is equipped with a waste gas discharge pipe, which is connected to the exhaust gas treatment system.

[0015] Preferably, the discharge pipe of the temporary storage vessel is provided with a three-way valve, one of which is connected to the filter, and the other is connected back to the return port at the top of the temporary storage vessel through a pipe.

[0016] Preferably, the temporary storage vessel is equipped with a pressurizing nitrogen inlet pipe, a purging nitrogen inlet pipe, and a solvent cleaning pipe. The pressurizing nitrogen inlet pipe and the purging nitrogen inlet pipe are respectively connected to the nitrogen supply system, and the solvent cleaning pipe is connected to the cleaning agent supply system. Both the nitrogen supply system and the cleaning agent supply system are electrically connected to the automatic control system.

[0017] Preferably, three material receiving troughs are arranged in parallel.

[0018] Preferably, two solvent receiving tanks are arranged in parallel.

[0019] Preferably, the automatic control system is a DCS automatic control system.

[0020] After adopting the above technical solution, the beneficial effects of this utility model are:

[0021] Automatic feeding is achieved through an automatic control system and flow meter, reducing the workload of operators and ensuring the accuracy of material input. Continuous, small-batch mixing effectively reduces the load on the mixing tank's refrigeration unit (especially in summer). Two consecutive cold reactions of different types effectively increase the controllability and prolong the cold reaction process, improving reaction efficiency. An intermediate reactor equipped with a temperature-controlled jacket preheats the materials, improving heat source utilization efficiency. Two consecutive hot reactions at 90-95°C increase the holding time (under control conditions), thus relatively improving production efficiency. The use of a temporary storage reactor separates the synthesis and filtration processes, allowing them to operate independently. Nitrogen purging removes residual phosgene, protecting equipment. The series connection of the filter and evaporator enables integrated operation, saving equipment and improving production efficiency.

[0022] In summary, this utility model enables continuous production, has a simple production process, and can effectively reduce labor intensity and improve work efficiency. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the structure of Embodiment 1 of the present utility model;

[0024] The components are as follows: 1. Mixing tank; 2. First cold reaction vessel; 3. Second cold reaction vessel; 4. Intermediate vessel; 5. First hot reaction vessel; 6. Second hot reaction vessel; 7. Third hot reaction vessel; 8. Temporary storage vessel; 9. Filter; 10. Thin-film evaporator; 11. Material receiving tank; 12. First dissolving vessel; 13. Second dissolving vessel; 14. Waste gas buffer tank; 15. First condenser; 16. Solvent receiving tank; 17. Second condenser; 18. Vacuum buffer tank; 19. Cooler. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present utility model and are not intended to limit the present utility model.

[0026] like Figure 1As shown, a continuous production apparatus for 1,5-naphthalene diisocyanate includes a mixing tank 1, a first cold reactor 2, a second cold reactor 3, an intermediate reactor 4, a first hot reactor 5, a second hot reactor 6, a third hot reactor 7, a temporary storage tank 8, a filter 9, a thin-film evaporator 10, and a material receiving tank 11, which are connected sequentially by pipes (not shown), valves (not shown), and pumps (not shown). The mixing tank 1 is connected to a first dissolving tank 12 and a second dissolving tank 13 by pipes and flow meters (not shown), respectively. The first cold reactor 2 and... Each intermediate reactor 4 is equipped with an exhaust port (located at the top) and a drain port (located at the bottom). The exhaust port is connected to the waste gas buffer tank 14 via a pipe (the waste gas buffer tank is used for the natural discharge of gases during the synthesis process to avoid gas blockage and affect material transportation; the drain port at the bottom of the buffer tank is used for the recovery of settled solvent; the drain ports at the bottom of the first cold reactor and intermediate reactors are for material transfer in emergency situations); the lower part of the temporary storage reactor 8 is equipped with a nitrogen input pipe (nitrogen is used to purge the feed pipe and filter) (not shown) and a discharge pipe (not shown). The upper part is equipped with a nitrogen pressurization pipe (nitrogen is used for filtration, pressurization, and purging of the vessel) (not labeled) and a gas output pipe (considered as a distillation column, its function is to evaporate the gaseous solvent in the vessel and rise into the first condenser) (not labeled). The gas output pipe is connected to the first condenser 15. The lower part of the first condenser 15 is also equipped with a U-shaped reflux pipe connected to the temporary storage vessel 8 (after condensation, it enters the lower U-shaped reflux pipe and flows back into the temporary storage vessel; a small amount of solvent that is not condensed enters the waste gas buffer tank for sedimentation and recovery through a pipeline). The first condenser 15 is connected to the waste gas buffer tank through a pipeline. Tank 14; The gas outlet of the thin film evaporator 10 is connected to the solvent receiving tank 16 via a pipe and cooler 19. The gas outlet of the solvent receiving tank 16 is connected to the second condenser 17 via a gas output pipe and a U-shaped return pipe. The second condenser 17 is also connected to the vacuum buffer tank 18 via a pipe. The vacuum buffer tank 18 is connected to the vacuum generator (not shown) via a pipe. Valves, flow meters, filters 9, thin film evaporator 10, first condenser 15, second condenser 17 and pump are all electrically connected to the automatic control system (not shown).

[0027] In practical applications, the raw material solid phosgene and solvent are first loaded into the first dissolving vessel 12 for cooling and stirring to dissolve. Then, 1,5-diaminonaphthalene and solvent are loaded into the second dissolving vessel 13 for heating and stirring to dissolve. The dissolved solid phosgene solution and 1,5-diaminonaphthalene solution are then quantitatively transported to the mixing tank 1 via flow meters. After thorough mixing, they are sequentially transported to the first cold reaction vessel 2 and the second cold reaction vessel 3 for cold reaction. The first cold reaction vessel 2 uses a spiral stirrer to ensure more uniform material mixing; the second cold reaction vessel 3 employs an internal pipeline structure to extend the material travel distance and provide the necessary temperature and time for material synthesis. After the cold reaction, the material enters... In intermediate reactor 4, preheating (40-45℃) and stirring are carried out to remove the small amount of hydrogen chloride gas generated during the cold reaction. Then, the mixture is transferred by a plunger pump to the first hot reactor 5 (90-95℃), the second hot reactor 6 (90-95℃), and the third hot reactor 7 (130-135℃) for hot reaction. After the hot reaction, the material is temporarily stored in temporary storage reactor 8 and then enters filter 9. Filter 9 is a backwashable filter. When cleaning after filtration, switch the three-way valve, close the discharge valve, open the pressurizing nitrogen, and purge filter 9. Then open the discharge valve again to dry the filter rod, close the discharge valve again to shut off the pressurizing nitrogen, and turn on the purging nitrogen and vibration buttons. After shutting off nitrogen and vibration, and waiting for atmospheric pressure, open the bottom cover to discharge activated carbon, then tighten the lock. Open the solvent valve to flush and restore the filtration mode. After filtration, the material is first evaporated and separated from the solvent and the pre-distillate by the thin-film evaporator 10 to obtain crude material, which is temporarily stored in the material receiving tank 11 for subsequent processing. The solvent evaporated by the thin-film evaporator 10 is condensed by the cooler 19 and enters the solvent receiving tank 16. After being condensed and refluxed by the second condenser 17, it is temporarily stored. The gas that is not condensed in the second condenser 17 enters the vacuum buffer tank 18, is drawn away by the vacuum generator, and is sent to the waste gas treatment device (not shown) for treatment before being discharged.

[0028] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A continuous production apparatus for 1,5-naphthalene diisocyanate, characterized in that: The system includes a mixing tank, a first cold reaction vessel, a second cold reaction vessel, an intermediate vessel, a first hot reaction vessel, a second hot reaction vessel, a third hot reaction vessel, a temporary storage vessel, a filter, a thin-film evaporator, and a material receiving tank, all connected sequentially via pipes, valves, and pumps. The mixing tank is connected to a first dissolving vessel and a second dissolving vessel via pipes and flow meters. Both the first cold reaction vessel and the intermediate vessel are equipped with exhaust ports and sludge discharge ports, with the exhaust ports connected to a waste gas buffer tank via pipes. The lower part of the temporary storage vessel is equipped with a nitrogen input pipe and a discharge pipe, while the upper part is equipped with a nitrogen pressurization pipe and a gas output pipe. The pipe connects to the first condenser, and the lower part of the first condenser is also provided with a U-shaped return pipe connecting to the temporary storage vessel. The first condenser is connected to the waste gas buffer tank through a pipe. The gas outlet of the thin film evaporator is connected to the solvent receiving tank through a pipe and a cooler. The gas outlet of the solvent receiving tank is connected to the second condenser through a gas output pipe and a U-shaped return pipe. The second condenser is also connected to the vacuum buffer tank through a pipe. The vacuum buffer tank is connected to the vacuum generator through a pipe. The valve, flow meter, filter, thin film evaporator, first condenser, second condenser and pump are all electrically connected to the automatic control system.

2. The continuous production apparatus for 1,5-naphthalene diisocyanate according to claim 1, characterized in that: The mixing tank, the first dissolving vessel, the second dissolving vessel, the first cold reaction vessel, the intermediate vessel, and the temporary storage vessel are all equipped with stirring devices.

3. The continuous production apparatus for 1,5-naphthalene diisocyanate according to claim 1, characterized in that: The second cold reactor, the first hot reactor, the second hot reactor, and the third hot reactor are all equipped with heat-insulating jackets on their exteriors, and each reactor is equipped with a pipeline-type material conveying pipe and a temperature sensor inside its interior.

4. The continuous production apparatus for 1,5-naphthalene diisocyanate according to claim 1, characterized in that: The mixing tank, the first dissolving vessel, the second dissolving vessel, the first cold reaction vessel, the intermediate vessel, and the temporary storage vessel are all equipped with temperature control jackets and temperature sensors.

5. The continuous production apparatus for 1,5-naphthalene diisocyanate according to claim 1, characterized in that: The waste gas buffer tank is equipped with a waste gas discharge pipe, which is connected to the exhaust gas treatment system.

6. The continuous production apparatus for 1,5-naphthalene diisocyanate according to claim 1, characterized in that: The discharge pipe of the temporary storage vessel is equipped with a three-way valve, one of which is connected to the filter, and the other is connected back to the return port at the top of the temporary storage vessel through a pipe.

7. The continuous production apparatus for 1,5-naphthalene diisocyanate according to claim 1, characterized in that: The temporary storage vessel is equipped with a nitrogen input pipe for pressing, a nitrogen input pipe for purging, and a solvent cleaning pipe.

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