Feed pipe structure of isocyanate reaction kettle

Abstract

The utility model relates to a feeding pipe structure of an isocyanate reaction kettle, and belongs to the technical field of chemical production. Comprising a main feeding pipe connected with a reaction kettle, the upper end of the main feeding pipe is connected to an isocyanate storage tank, a discharging on-off valve is arranged at the end, connected with the isocyanate storage tank, of the main feeding pipe, and a bypass pipe is connected to the pipe wall, connected with an outlet of the discharging on-off valve, of the main feeding pipe; a compressed air on-off valve is installed on the compressed air supply pipeline, a third connector of the three-way connector A is connected with a first connector of the three-way connector B through a water supply branch pipe A, a second connector of the three-way connector B is connected with a pipeline cleaning hot water supply pipeline, and a hot water on-off valve A is installed on the water supply branch pipe A. The utility model has the beneficial effects that the cleaning operation of the feeding main pipe can be realized, isocyanate is effectively prevented from depositing on the inner wall of the feeding main pipe, the service life of the feeding main pipe is prolonged, the reliability of the feeding main pipe is improved, the safety is higher, and meanwhile, manpower is saved.

Description

Technical Field

[0001] This utility model relates to a feed pipe structure for an isocyanate reactor, belonging to the field of chemical production technology. Background Technology

[0002] Blocked polyurethane is a product obtained by capping isocyanate groups with a blocking agent. In existing processes for preparing blocked isocyanates, isocyanate monomers and blocking agents are usually added to a reactor and reacted to synthesize the blocked isocyanate. The resulting reaction product is then transported from the reactor to a storage tank.

[0003] A search revealed a utility model patent with patent number 201621426245.1, which discloses a production system for blocked isocyanates, belonging to the field of blocked isocyanate preparation technology. It includes a reaction vessel unit, a storage unit, and a discharge unit. The reaction vessel unit includes a reaction vessel body and a stirring mechanism for stirring the reactants within the reaction vessel body. The storage unit includes a storage tank for storing the reaction products. The discharge unit includes a discharge pump, a reflux pump, and a product delivery pipe. The discharge pump is connected to the storage unit via the product delivery pipe, and a reflux pipe is provided on the product delivery pipe, which is connected to a reflux outlet via the reflux pump. By combining the reaction vessel unit, storage unit, and discharge unit into a system, the reaction process, storage process, and output process constitute a complete production process.

[0004] While the aforementioned patent enables the production of closed-loop isocyanates, its current technological considerations are incomplete and have the following drawbacks: 1. It lacks a preheating device for isocyanates. 2. The isocyanates in the storage tank need to be transported to the reactor via the feed main pipe. Isocyanates depositing in the delivery pipeline can clog it, requiring operators to cut and reinstall the pipe.

[0005] To solve one of the above problems, there is an urgent need for a new isocyanate reactor feed pipe structure. Utility Model Content

[0006] Based on the shortcomings of the prior art, the technical problem to be solved by this utility model is: how to achieve the cleaning operation of the feed pipe, effectively prevent isocyanate from depositing on the inner wall of the feed pipe, improve the life and reliability of the feed pipe, enhance safety, and save manpower. To this end, an isocyanate reactor feed pipe structure is provided.

[0007] The isocyanate reactor feed pipe structure of this utility model includes a main feed pipe connected to the reactor, the upper end of which is connected to an isocyanate storage tank. The structure is characterized by: a discharge on / off valve being provided at one end of the main feed pipe connected to the isocyanate storage tank; a bypass pipe being connected to the wall of the main feed pipe connected to the outlet of the discharge on / off valve; the other end of the bypass pipe being connected to the first interface of a tee connector A; a compressed air supply pipe being connected to the second interface of the tee connector A; a compressed air on / off valve being installed on the compressed air supply pipe; a third interface of the tee connector A being connected to the first interface of a tee connector B via a water supply branch pipe A; and a hot water on / off valve A being installed on the water supply branch pipe A.

[0008] First, the isocyanate storage tank is pressurized for discharge. Then, the discharge valve is opened, allowing the isocyanate in the storage tank to enter the reactor via the discharge valve and the main feed pipe. Once the isocyanate filling is complete, the discharge valve is closed, and the sealing agent is added through the remaining filling ports. After all raw materials have been added, the reactor is opened to produce sealed isocyanate. In this application, after reactor 1 has completed the production of sealed isocyanate and discharged, the hot water valve A is opened. The hot water supplied by the pipeline cleaning hot water supply pipe flushes the main feed pipe through the hot water valve A, tee connector A, and bypass pipe. The hot water discharged from the main feed pipe flows into the reactor. The reactor's agitator can also be turned on to clean the reactor. After flushing the main feed pipe, the hot water valve A is closed, and the compressed air valve is opened to purge the main feed pipe. After the reactor is cleaned, the waste liquid in the reactor is discharged.

[0009] This invention enables the cleaning of the feed pipe, effectively preventing isocyanate from depositing on the inner wall of the feed pipe, improving the lifespan and reliability of the feed pipe, enhancing safety, and saving manpower.

[0010] Tank discharge pressurization is a conventional technique. The principle involves using compressed air or nitrogen to force a compressed medium into the tank, increasing its internal pressure and thus achieving the purpose of pressurizing the discharge. During pressurization, it is crucial to carefully control the pressurization rate and pressure to avoid damaging the tank.

[0011] Preferably, a flow meter is also installed on the water supply branch pipe A between the hot water on / off valve A and the tee connector A. This allows monitoring of the hot water flow rate injected into the main feed pipe; when the preset flow rate is reached, the hot water on / off valve A is closed.

[0012] Preferably, the feed main pipe is connected to the reactor via a pipeline-type temperature rise device, which can be used to raise the temperature of the isocyanate before the reaction to ensure the production of closed isocyanate.

[0013] Preferably, the pipeline-type temperature rise device includes a heat exchange box, in which partition A and partition B are provided, dividing the heat exchange box into an inlet chamber, a heat exchange chamber, and an outlet chamber. Both partition A and partition B are penetrated by heat exchange tubes, one end of which is located in the inlet chamber and the other end of which is located in the outlet chamber. An inlet pipe communicating with the inlet chamber and an outlet pipe communicating with the outlet chamber are fixed on the outer wall of the heat exchange box. One end of the heat exchange box is provided with an end connecting pipe A communicating with the heat exchange chamber, and the end connecting pipe A has an upper connecting flange. The other end of the heat exchange box is installed with an end connecting pipe B communicating with the heat exchange chamber. The end connecting pipe B has upper and lower connecting flanges, the upper connecting flange is connected to the feed main pipe, and the lower connecting flange is connected to the liquid inlet of the reactor.

[0014] After the feed shut-off valve is opened, the compressed air shut-off valve and the hot water shut-off valve A are closed, but the hot water shut-off valve B can be opened. The hot water supplied by the pipeline cleaning hot water supply pipeline enters the inlet chamber through the water supply branch pipe B, and then enters the outlet chamber through the heat exchange pipe. The isocyanate flowing through the heat exchange chamber exchanges heat with the heat exchange pipe, which can raise the temperature of the isocyanate. The warm water in the outlet chamber is discharged into the recovery tank through the outlet pipe.

[0015] Preferably, multiple heat exchange tubes are provided, and the heat exchange tubes are straight tubes or circuitous heat exchange tubes. This can increase the heat exchange area and improve the heat exchange efficiency.

[0016] Preferably, a water supply branch pipe B is connected to the third interface of the tee connector B, a hot water on / off valve B is installed on the water supply branch pipe B, the other end of the water supply branch pipe B is connected to the inlet pipe, and the outlet pipe is connected to the return pipe. Using the same set of pipes to clean the hot water supply pipeline reduces construction costs.

[0017] Preferably, the system further includes a controller and a temperature sensor located on the end connecting pipe B. The signal input terminal of the controller is connected to the flow meter and the temperature sensor, and the signal input terminal of the controller is also connected to the compressed air on / off valve, the hot water on / off valve A, and the hot water on / off valve B. The temperature sensor detects the temperature of the isocyanate flowing through the feed main pipe. If the temperature is low, it controls the hot water on / off valve B to open; otherwise, it controls the hot water on / off valve B to close.

[0018] After the reactor completes the production of sealed isocyanate and discharges the material, the controller can control the opening and closing of the corresponding on / off valves as needed to achieve automatic control. Specifically, the hot water on / off valve A is opened first, and after the flow meter detects that the predetermined water output has been reached, the hot water on / off valve A is closed. Then, the compressed air on / off valve is opened, and after the compressed air on / off valve has reached the predetermined time, the compressed air on / off valve is closed in a timely manner.

[0019] Preferably, the controller is a PLC programmable controller.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] The isocyanate reactor feed pipe structure described in this utility model enables the cleaning of the feed pipe, effectively preventing isocyanate from depositing on the inner wall of the feed pipe, improving the life and reliability of the feed pipe, enhancing safety, and saving manpower.

[0022] The feed pipe structure of the isocyanate reactor described in this utility model is connected to the reactor via a pipeline-type temperature rise device, which can be used to raise the temperature of the isocyanate before the reaction to ensure the production of sealed isocyanate.

[0023] The isocyanate reactor feed pipe structure of this utility model has multiple heat exchange tubes, which can be straight or meandering, thereby increasing the heat exchange area and improving the heat exchange efficiency.

[0024] The isocyanate reactor feed pipe structure of this utility model includes a water supply branch pipe B connected to the third interface of the tee connector B. A hot water on / off valve B is installed on the water supply branch pipe B, and the other end of the water supply branch pipe B is connected to the inlet pipe. The outlet pipe is connected to the return pipe. Using the same set of pipes to clean the hot water supply pipeline reduces construction costs. Attached Figure Description

[0025] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the accompanying drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. In all the drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, the elements or parts are not necessarily drawn to scale.

[0026] Figure 1 This is a schematic diagram of the structure of this utility model;

[0027] Figure 2 This is a schematic diagram of the internal structure of the pipeline-type temperature rise device of this utility model;

[0028] In the diagram: 1. Reactor; 2. Main feed pipe; 3. Bypass pipe; 4. T-joint A; 5. Compressed air supply pipe; 6. Compressed air on / off valve; 7. Hot water supply pipe for pipe cleaning; 8. Hot water on / off valve A; 9. T-joint B; 10. Hot water on / off valve B; 11. Water supply branch pipe A; 12. Water supply branch pipe B; 13. Flow meter; 14. Discharge on / off valve; 15. Heat exchanger; 16. Baffle A; 17. Baffle B; 18. Upper connecting flange; 19. Lower connecting flange; 20. Heat exchanger tube; 21. Inlet pipe; 22. Outlet pipe; 23. Controller; 24. Temperature sensor; 25. Isocyanate storage tank. Detailed Implementation

[0029] The present invention will be further described below with reference to the accompanying drawings: The present invention will be further described below through specific embodiments, but it is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

[0030] Example 1, as Figure 1 As shown, the isocyanate reactor feed pipe structure includes a main feed pipe 2 connected to the reactor 1. The upper end of the main feed pipe 2 is connected to an isocyanate storage tank. A discharge shut-off valve 14 is provided at one end of the main feed pipe 2 connected to the isocyanate storage tank. A bypass pipe 3 is connected to the pipe wall of the main feed pipe 2 connected to the outlet of the discharge shut-off valve 14. The other end of the bypass pipe 3 is connected to the first interface of a three-way connector A4. A compressed air supply pipe 5 is connected to the second interface of the three-way connector A4. A compressed air shut-off valve 6 is installed on the compressed air supply pipe 5. The third interface of the three-way connector A4 is connected to the first interface of a three-way connector B9 through a water supply branch pipe A11. The second interface of the three-way connector B9 is connected to a hot water supply pipe 7 for pipe cleaning. A hot water shut-off valve A8 is installed on the water supply branch pipe A11.

[0031] First, the isocyanate storage tank 25 is pressurized for discharge. Then, the discharge shut-off valve 14 is opened. The isocyanate in the isocyanate storage tank enters the reactor 1 through the discharge shut-off valve 14 and the feed main pipe 2. After the isocyanate is completely added, the discharge shut-off valve 14 is closed, and the sealing agent is added through the other filling ports. After all raw materials are added, the reactor 1 is opened to produce sealed isocyanate. After the reactor 1 has completed the production of sealed isocyanate and discharged, the hot water shut-off valve A8 is opened. The hot water supplied by the pipeline cleaning hot water supply pipe 7 is flushed through the hot water shut-off valve A8, the three-way connector A4, and the bypass pipe 3 to flush the feed main pipe 2. The hot water discharged through the feed main pipe 2 flows into the reactor 1. Alternatively, the agitator of the reactor 1 can be turned on to clean the reactor 1. After the feed pipe 2 has been rinsed, close the hot water on / off valve A8 and open the compressed air on / off valve 6 to blow the feed pipe 2 clean. After the reactor 1 has been cleaned, discharge the waste liquid in the reactor 1.

[0032] This invention enables the cleaning of the feed pipe 2, effectively preventing isocyanate from depositing on the inner wall of the feed pipe 2, improving the lifespan and reliability of the feed pipe 2, enhancing safety, and saving manpower.

[0033] Tank discharge pressurization is a conventional technique. The principle involves using compressed air or nitrogen to force a compressed medium into the tank, increasing its internal pressure and thus achieving the purpose of pressurizing the discharge. During pressurization, it is crucial to carefully control the pressurization rate and pressure to avoid damaging the tank.

[0034] Example 2, as Figure 1-2 As shown, the isocyanate reactor feed pipe structure includes a main feed pipe 2 connected to the reactor 1. The upper end of the main feed pipe 2 is connected to an isocyanate storage tank. A discharge shut-off valve 14 is provided at one end of the main feed pipe 2 connected to the isocyanate storage tank. A bypass pipe 3 is connected to the pipe wall of the main feed pipe 2 connected to the outlet of the discharge shut-off valve 14. The other end of the bypass pipe 3 is connected to the first interface of a three-way connector A4. A compressed air supply pipe 5 is connected to the second interface of the three-way connector A4. A compressed air shut-off valve 6 is installed on the compressed air supply pipe 5. The third interface of the three-way connector A4 is connected to the first interface of a three-way connector B9 through a water supply branch pipe A11. The second interface of the three-way connector B9 is connected to a hot water supply pipe 7 for pipe cleaning. A hot water shut-off valve A8 is installed on the water supply branch pipe A11.

[0035] Furthermore, a flow meter 13 is installed on the water supply branch pipe A11 between the hot water on / off valve A8 and the tee connector A4. This flow meter can monitor the flow rate of the hot water injected into the main feed pipe 2. When the preset flow rate is reached, the hot water on / off valve A8 is controlled to close.

[0036] Furthermore, the feed pipe 2 is connected to the reactor 1 via a pipeline temperature rise device, which can be used to raise the temperature of the isocyanate before the reaction to ensure the production of closed isocyanate.

[0037] Furthermore, the pipeline-type temperature rise device includes a heat exchange box 15, which is equipped with a partition A16 and a partition B17. The partition A16 and partition B17 divide the heat exchange box 15 into an inlet chamber, a heat exchange chamber, and an outlet chamber. Both partition A16 and partition B17 are penetrated by heat exchange tubes 20. One end of the heat exchange tube 20 is located in the inlet chamber, and the other end of the heat exchange tube 20 is located in the outlet chamber. A connection to the inlet chamber is fixed on the outer wall of the heat exchange box 15. The heat exchange box 15 is equipped with an inlet pipe 21 and an outlet pipe 22 connected to the liquid outlet chamber. One end of the heat exchange box 15 is provided with an end connecting pipe A connected to the heat exchange chamber. The end connecting pipe A has an upper connecting flange 18. The other end of the heat exchange box 15 is equipped with an end connecting pipe B connected to the heat exchange chamber. The end connecting pipe B has upper and lower connecting flanges 19. The upper connecting flange 18 is connected to the feed pipe 2, and the lower connecting flange 19 is connected to the liquid inlet of the reactor 1.

[0038] After the feed shut-off valve 14 is opened, the compressed air shut-off valve 6 and the hot water shut-off valve A8 are closed, but the hot water shut-off valve B10 can be opened. The hot water supplied by the pipeline cleaning hot water supply pipe 7 enters the inlet chamber through the water supply branch pipe B12, and then enters the outlet chamber through the heat exchange pipe 20. The isocyanate flowing through the heat exchange chamber exchanges heat with the heat exchange pipe 20, which can raise the temperature of the isocyanate. The warm water in the outlet chamber is discharged into the recovery tank through the water outlet pipe 22.

[0039] Furthermore, multiple heat exchange tubes 20 are provided, and the heat exchange tubes 20 can be straight tubes or be arranged in a circuitous manner. This can increase the heat exchange area and improve the heat exchange efficiency.

[0040] Furthermore, a water supply branch pipe B12 is connected to the third interface of the tee connector B9, and a hot water on / off valve B10 is installed on the water supply branch pipe B12. The other end of the water supply branch pipe B12 is connected to the inlet pipe 21, and the outlet pipe 22 is connected to the return pipe. Using the same set of pipes to clean the hot water supply pipe 7 reduces construction costs.

[0041] Furthermore, it also includes a controller 23 and a temperature sensor 24 located on the end connecting pipe B. The signal input terminal of the controller 23 is connected to the flow meter 13 and the temperature sensor 24, and the signal input terminal of the controller 23 is connected to the compressed air on / off valve 6, the hot water on / off valve A8, and the hot water on / off valve B10. The temperature sensor 24 detects the temperature of the isocyanate flowing through the feed main pipe 2. If the temperature is low, it controls the hot water on / off valve B10 to open; otherwise, it controls the hot water on / off valve B10 to close.

[0042] After the reactor 1 completes the production of sealed isocyanate and discharges the material, the controller 23 can control the opening and closing of the corresponding on / off valves as needed to complete automatic control. Specifically, the hot water on / off valve A8 is opened first, and after the flow meter 13 detects that the predetermined water output has been reached, the hot water on / off valve A8 is closed. Then, the compressed air on / off valve 6 is opened, and after the compressed air on / off valve 6 has reached the predetermined time, the compressed air on / off valve 6 is closed in a timely manner.

[0043] Furthermore, the controller 23 is a PLC programmable controller.

[0044] This utility model relates to a specific embodiment in which the modification of the prior art lies in the hardware part, and the computer program involved is a simple program whose functions can be easily implemented by those skilled in the art using existing computer program development platforms and well-known programming methods.

[0045] In this article, the compressed air on / off valve 6, hot water on / off valve A8, hot water on / off valve B10, flow meter 13 and controller 23 are only used in a simple way, and do not involve any improvement to the methods or procedures.

[0046] The isocyanate reactor feed pipe structure described in this utility model enables the cleaning of the feed pipe, effectively preventing isocyanate from depositing on the inner wall of the feed pipe, improving the life and reliability of the feed pipe, enhancing safety, and saving manpower.

[0047] The feed pipe structure of the isocyanate reactor described in this utility model is connected to the reactor via a pipeline-type temperature rise device, which can be used to raise the temperature of the isocyanate before the reaction to ensure the production of sealed isocyanate.

[0048] The isocyanate reactor feed pipe structure of this utility model has multiple heat exchange tubes, which can be straight or meandering, thereby increasing the heat exchange area and improving the heat exchange efficiency.

[0049] The isocyanate reactor feed pipe structure of this utility model includes a water supply branch pipe B connected to the third interface of the tee connector B. A hot water on / off valve B is installed on the water supply branch pipe B, and the other end of the water supply branch pipe B is connected to the inlet pipe. The outlet pipe is connected to the return pipe. Using the same set of pipes to clean the hot water supply pipeline reduces construction costs.

[0050] The foregoing has shown and described the basic principles, main features, and advantages of this utility model. Those skilled in the art should understand that this utility model is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to this utility model without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claims. The scope of protection of this utility model is defined by the appended claims and their equivalents.

[0051] Any aspects of this invention not described in detail are well-known to those skilled in the art.

Claims

1. A feed pipe structure for an isocyanate reactor, comprising a main feed pipe connected to the reactor, the upper end of the main feed pipe being connected to an isocyanate storage tank, characterized in that: A discharge shut-off valve is installed at one end of the feed main pipe connected to the isocyanate storage tank. A bypass pipe is connected to the wall of the feed main pipe connected to the outlet of the discharge shut-off valve. The other end of the bypass pipe is connected to the first interface of the tee connector A. The second interface of the tee connector A is connected to a compressed air supply pipeline. A compressed air shut-off valve is installed on the compressed air supply pipeline. The third interface of the tee connector A is connected to the first interface of the tee connector B through a water supply branch pipe A. The second interface of the tee connector B is connected to a hot water supply pipeline for pipeline cleaning. A hot water shut-off valve A is installed on the water supply branch pipe A.

2. The isocyanate reactor feed pipe structure according to claim 1, characterized in that, A flow meter is also installed on the water supply branch pipe A between the hot water on / off valve A and the tee connector A.

3. The isocyanate reactor feed pipe structure according to claim 1 or 2, characterized in that, The main feed pipe is connected to the reactor via a pipeline-type temperature rise device.

4. The isocyanate reactor feed pipe structure according to claim 3, characterized in that, The pipeline-type temperature rise device includes a heat exchange box, which is equipped with partition A and partition B. Partition A and partition B divide the heat exchange box into an inlet chamber, a heat exchange chamber, and an outlet chamber. Both partition A and partition B are penetrated by heat exchange tubes. One end of each heat exchange tube is located in the inlet chamber, and the other end is located in the outlet chamber. An inlet pipe connected to the inlet chamber and an outlet pipe connected to the outlet chamber are fixed on the outer wall of the heat exchange box. One end of the heat exchange box is provided with an end connecting pipe A connected to the heat exchange chamber, and the end connecting pipe A has an upper connecting flange. The other end of the heat exchange box is equipped with an end connecting pipe B connected to the heat exchange chamber. The end connecting pipe B has upper and lower connecting flanges. The upper connecting flange is connected to the feed main pipe, and the lower connecting flange is connected to the liquid inlet of the reactor.

5. The isocyanate reactor feed pipe structure according to claim 4, characterized in that, The heat exchange tubes are provided in multiple ways, and the heat exchange tubes are either straight tubes or heat exchange tubes arranged in a circuitous manner.

6. The isocyanate reactor feed pipe structure according to claim 4, characterized in that, The third port of the three-way connector B is connected to a water supply branch pipe B, a hot water on / off valve B is installed on the water supply branch pipe B, the other end of the water supply branch pipe B is connected to the inlet pipe, and the outlet pipe is connected to the return pipe.

7. The isocyanate reactor feed pipe structure according to claim 6, characterized in that, It also includes a controller and a temperature sensor located on the end connecting pipe B. The signal input terminal of the controller is connected to the flow meter and the temperature sensor, and the signal input terminal of the controller is connected to the compressed air on / off valve, the hot water on / off valve A and the hot water on / off valve B.

8. The isocyanate reactor feed pipe structure according to claim 7, characterized in that, The controller is a PLC programmable controller.

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