1, 5-diaminonaphthalene dissolving and dehydrating device

Abstract

The utility model relates to the technical field of chemical equipment, in particular to a 1, 5-diaminonaphthalene dissolving and dehydrating device which comprises a dehydrating kettle and a plurality of dissolving kettles which are communicated with each other, and the dehydrating kettle and the dissolving kettles are respectively provided with a temperature control jacket and a stirring device; the top of the dehydration kettle is provided with a feed port, a nitrogen input port, a pressure stabilizing device and a vacuumizing system, and the bottom is provided with a discharge port; a discharge port of the dehydration kettle is communicated with a mixing pipe arranged at the top of the dissolving kettle, the bottom of the mixing pipe is communicated with the top of the dissolving kettle, and the top of the mixing pipe is communicated with a circulating pipeline of the dissolving kettle; the top of the dissolving kettle is also communicated with a solvent input pipe and a tail gas discharge pipe, the solvent input pipe is communicated to a solvent storage tank through a drying filter, and the tail gas discharge pipe is communicated to a tail gas treatment device through a condenser; a discharge hole is formed in the bottom of the dissolving kettle and is respectively communicated with the circulating pipeline and the cold reaction kettle through pipelines. The continuous dehydrating and dissolving device can be used for continuously dehydrating and dissolving production raw materials, ensures the production continuity and is high in production efficiency.

Description

Technical Field

[0001] This utility model relates to the field of chemical equipment technology, specifically to a 1,5-diaminonaphthalene dissolution and dehydration device. Background Technology

[0002] 1,5-Diaminonaphthalene (NDA) is the main raw material for the specialty high-performance isocyanate 1,5-naphthalene diisocyanate (NDI). Polyurethane synthesized from 1,5-naphthalene diisocyanate possesses excellent properties such as high strength, high deformation stability, high abrasion resistance, high tear strength, and high elasticity, leading to increasing demand for NDA. Currently, 1,5-diaminonaphthalene is mainly prepared by ammonolysis of 1,5-naphthyldiphenol or by hydrogenation of 1,5-dinitronaphthalene. Both synthetic methods require purification, primarily involving crystallization and washing. The purification process requires large amounts of solvents or water, often low-boiling-point amines or alcohols. These solvents or water residues can remain in the 1,5-diaminonaphthalene, affecting subsequent 1,5-naphthalene diisocyanate production. The existing process for synthesizing 1,5-naphthalene diisocyanate involves mixing a fixed amount of 1,5-diaminonaphthalene with a solvent, heating the mixture, and then using an azeotropic process to distill off or remove water and low-boiling substances. Other raw materials are then added for subsequent reactions. A single batch of 100 kg of 1,5-diaminonaphthalene requires approximately 1.5 tons of solvent, and the heating, distillation, and dehydration process takes about 2 hours, including approximately 40 minutes of heating and 1 hour and 20 minutes of reflux. This production method severely restricts production continuity, is labor-intensive, and has low production efficiency. Summary of the Invention

[0003] The technical problem to be solved by this utility model is to provide a 1,5-diaminonaphthalene dissolution and dehydration device, which overcomes the defects of the prior art, enables continuous dehydration and dissolution of raw materials, ensures the continuity of production, and has high production efficiency.

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

[0005] A 1,5-diaminonaphthalene dissolution and dehydration device includes a dehydration vessel and several dissolution vessels connected by pipes, valves, and pumps. Both the dehydration vessel and the dissolution vessel are equipped with temperature control jackets and stirring devices. The top of the dehydration vessel is equipped with a feed inlet, a nitrogen inlet, a pressure stabilizing device, and a vacuum system, while the bottom is equipped with a discharge outlet. The discharge outlet of the dehydration vessel is connected to a mixing pipe located at the top of the dissolution vessel via pipes and valves. The bottom of the mixing pipe is connected to the top of the dissolution vessel, and the top of the mixing pipe is connected to a circulation pipe for the dissolution vessel. The top of the dissolution vessel is also connected to a solvent input pipe and a tail gas discharge pipe. The solvent input pipe is connected to a solvent storage tank via a drying filter, and the tail gas discharge pipe is connected to a tail gas treatment device via a condenser. The bottom of the dissolution vessel is equipped with a discharge outlet, which is connected to a circulation pipe and a cold reaction vessel via pipes.

[0006] Preferably, two to three dissolving kettles are connected in parallel. They can be used alternately to ensure continuous production.

[0007] Preferably, the dissolving vessel is also equipped with a pressure stabilizing device, which includes a pressure gauge, an interlocked nitrogen valve, and a safety valve.

[0008] Preferably, the temperature control jackets of the dehydration kettle and the dissolving kettle are both oil circulation temperature control jackets. The lower part of the oil circulation temperature control jacket is connected to the heat transfer oil supply device through pipes, valves and pumps, and the upper part of the oil circulation temperature control jacket is connected to the heat transfer oil recovery device through pipes, valves and pumps.

[0009] Preferably, the feed inlet of the dehydration kettle is connected to the ton bag feeding device, and the nitrogen input port is connected to the nitrogen supply device through a pipeline; the pressure stabilizing device includes a pressure gauge, an interlocked nitrogen valve, and a safety valve.

[0010] Preferably, the vacuum system includes a vacuum pump, and three buffer tanks connected in series between the vacuum pump and the dehydration vessel: a first buffer tank, a second buffer tank (the second buffer tank is filled with polyester polyol with a molecular weight of 1000 to wash away low-boiling substances brought in by the vacuum pump), and a third buffer tank. The other end of the vacuum pump is connected to a tail gas treatment device. The three buffer tanks connected in series can condense and temporarily store water and low-boiling substances, which are then discharged in a concentrated manner. The remaining tail gas is transported to the tail gas treatment device for treatment by the vacuum pump.

[0011] Preferably, the dryer filter is model ZD-320, manufactured by Haining Zhengda Filtration Equipment Co., Ltd.

[0012] Preferably, the condenser is model 3JK-38 and manufactured by Nantong Graphite Equipment Factory.

[0013] Preferably, a circulation pump is installed on the circulation pipeline. The circulation pump is model FJX-50-32-160, manufactured by Jingjiang Heli Pump Industry Co., Ltd.

[0014] Due to the adoption of the above technical solution, the beneficial effects of this utility model are:

[0015] This invention first uses a dehydration kettle to perform vacuum high-temperature distillation on 1,5-diaminonaphthalene to remove water and low-boiling substances, which are then removed through a vacuum system. The pre-dehydrated 1,5-diaminonaphthalene is further heated and melted into a liquid state in the dehydration kettle, then transferred to a dissolving kettle. There, it is mixed with a solvent, heated, and circulated to continue dissolving and mixing. During dissolution, due to the high temperature, the solvent evaporates, and the evaporated solvent is condensed and returned to the dissolving kettle. Simultaneously, the dissolution and mixing process is accelerated through a circulation pipeline. After dissolution, the material is transferred to a cold reaction kettle for subsequent production. Because multiple dissolving kettles are provided, they can be used alternately. Furthermore, the vacuum high-temperature dehydration significantly shortens the dehydration time, thus ensuring continuous production.

[0016] In summary, this invention enables continuous dehydration and dissolution of raw materials, ensuring continuous production and high production efficiency. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the device structure according to an embodiment of the present utility model;

[0018] In the diagram, 1 is the dehydration vessel; 2 is the dissolving vessel; 3 is the pressure stabilizing device; 4 is the vacuum system; 41 is the vacuum pump; 42 is the buffer tank; 5 is the mixing pipe; 6 is the circulation pipe; 7 is the drying filter; 8 is the solvent storage tank; 9 is the condenser; 10 is the tail gas treatment device; and 11 is the cold reaction vessel. Detailed Implementation

[0019] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0020] like Figure 1As shown, a 1,5-diaminonaphthalene dissolution and dehydration device includes a dehydration vessel 1 connected by pipes (not shown), valves (not shown), and a pump (not shown) and three dissolution vessels 2 arranged in parallel. Both the dehydration vessel 1 and the dissolution vessel 2 are equipped with temperature control jackets (not shown) and stirring devices (not shown). The top of the dehydration vessel 1 has a feed inlet (not shown), a nitrogen inlet (not shown), a pressure stabilizing device 3, and a vacuum system 4, and the bottom has a discharge outlet (not shown). The discharge outlet of the dehydration vessel 1 is connected to a device via pipes and valves. A mixing pipe 5 is placed at the top of the dissolving vessel 2. The bottom of the mixing pipe 5 is connected to the top of the dissolving vessel 2, and the top of the mixing pipe 5 is connected to the circulation pipe 6 of the dissolving vessel 2. The top of the dissolving vessel 2 is also connected to a solvent input pipe (not shown) and a tail gas discharge pipe (not shown). The solvent input pipe is connected to the solvent storage tank 8 through a drying filter 7, and the tail gas discharge pipe is connected to the tail gas treatment device 10 through a condenser 9. The bottom of the dissolving vessel 2 is provided with a discharge port (not shown), which is connected to the circulation pipe 6 and the cold reaction vessel 11 through pipes.

[0021] The feed inlet of the dehydration vessel 1 is connected to the ton bag feeding device (not shown) via a pipeline, and the nitrogen input port is connected to the nitrogen supply device (not shown) via a pipeline; the vacuum system 4 includes a vacuum pump 41, and three buffer tanks 42 connected in series between the vacuum pump 41 and the dehydration vessel 1 are provided, and the other end of the vacuum pump 41 is connected to the exhaust gas treatment device (not shown).

[0022] In actual production, the 1,5-diaminonaphthalene to be processed is fed into the dehydration vessel 1 through the feed inlet. The vessel is sealed, and the temperature is raised by oil bath heating. The stirring and vacuum system 4 is turned on (until the pressure inside the vessel is -0.08 to 0.098 MPa). The water and low-boiling substances in the material begin to volatilize as the stirring and the temperature inside the vessel rise. When the material temperature reaches 185℃, the 1,5-diaminonaphthalene is completely melted. After holding at this temperature for 10 minutes, it can be transferred to the dissolving vessel 2 for dissolution. At this time, the water and low-boiling substances in the material are completely distilled out. The steam generated during the distillation process is continuously fed into three buffer tanks 42 by the vacuum pump 41. The steam of water and low-boiling substances enters the first buffer tank for brief cooling and separation, then enters the second buffer tank for washing, and then enters the third buffer tank for collection. The tail gas is sent to the tail gas treatment device for treatment by the vacuum pump 41.

[0023] After the heat preservation is completed, close the valve of the second buffer tank, open the vent valve of the third buffer tank, then close the vacuum pump 41, open the nitrogen valve on the dehydration kettle 1 to fill with nitrogen to eliminate the vacuum, until the positive pressure is about 0.02MPa, and start to transport the material from the dehydration kettle 1 to the dissolving kettle 2.

[0024] While the material in dehydration vessel 1 is being dehydrated, the solvent dried by the drying filter 7 is transferred to dissolving vessel 2 and heated. The temperature is initially raised to 90°C, and then gradually increased to 130°C as the high-temperature material (1,5-diaminonaphthalene at 185°C) is added from dehydration vessel 1 (the addition of the high-temperature material increases the solution temperature and solubility, thus meeting the dissolution requirements while saving energy). The circulation pump is started for circulation, and the pressure stabilizing device is activated to maintain the pressure inside the vessel at 0.05–0.1 MPa. After the pressure stabilizes, the dehydrated material from dehydration vessel 1 is transferred to the dissolving vessel 2. In dissolving kettle 2, the conveying time is controlled within 30 minutes. Due to the entry of high-temperature materials, a small amount of solvent will evaporate. The evaporated gas enters condenser 9 for cooling and then flows back to dissolving kettle 2. The remaining steam enters the tail gas treatment device for treatment. The entire process, from dissolution and mixing in dehydration kettle 1 to dissolving kettle 2, takes about 40 minutes to process 100 kg of 1,5-diaminonaphthalene. In contrast, the existing technology takes about 2 hours to process the same amount of material. The processed material is transported through the outlet of dissolving kettle 2 and pipeline to the cold reaction kettle 11 of the next process for further processing.

[0025] Because three dissolving kettles are set up in parallel, they can be used alternately. During dehydration, the amount of material can be added at once according to the amount of the three dissolving kettles. This way, the metering device can be installed, which reduces the number of feedings and operation frequency, thus ensuring the continuity of production.

[0026] It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the present invention. Furthermore, it should be understood that after reading the teachings of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined by the appended claims.

Claims

1. A device for dissolving and dehydrating 1,5-diaminonaphthalene, characterized in that: The apparatus includes a dehydration vessel and several dissolving vessels connected by pipes, valves, and pumps. Both the dehydration and dissolving vessels are equipped with temperature control jackets and stirring devices. The dehydration vessel has a feed inlet, a nitrogen inlet, a pressure stabilizing device, and a vacuum system at the top, and a discharge outlet at the bottom. The discharge outlet of the dehydration vessel is connected to a mixing pipe located at the top of the dissolving vessel via pipes and valves. The bottom of the mixing pipe is connected to the top of the dissolving vessel, and the top of the mixing pipe is connected to a circulation pipe for the dissolving vessel. The top of the dissolving vessel is also connected to a solvent input pipe and a tail gas discharge pipe. The solvent input pipe is connected to a solvent storage tank via a drying filter, and the tail gas discharge pipe is connected to a tail gas treatment device via a condenser. The bottom of the dissolving vessel has a discharge outlet, which is connected to a circulation pipe and a cold reaction vessel via pipes.

2. The 1,5-diaminonaphthalene dissolution and dehydration apparatus as described in claim 1, characterized in that: Two to three dissolving kettles are connected in parallel.

3. The 1,5-diaminonaphthalene dissolution and dehydration apparatus as described in claim 1, characterized in that: The temperature control jackets of both the dehydration kettle and the dissolving kettle are oil circulation temperature control jackets.

4. The 1,5-diaminonaphthalene dissolution and dehydration apparatus as described in claim 1, characterized in that: The feed inlet of the dehydration kettle is connected to the ton bag feeding device via a pipeline, and the nitrogen input port is connected to the nitrogen supply device via a pipeline; the pressure stabilizing device includes a pressure gauge, an interlocked nitrogen valve, and a safety valve.

5. The 1,5-diaminonaphthalene dissolution and dehydration apparatus as described in claim 1, characterized in that: The vacuum system includes a vacuum pump, and three buffer tanks connected in series between the vacuum pump and the dehydration vessel are the first buffer tank, the second buffer tank, and the third buffer tank.

6. The 1,5-diaminonaphthalene dissolution and dehydration apparatus as described in claim 1, characterized in that: A circulation pump is installed on the circulation pipeline.

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