A system for reducing chlorine in the hydrolysis of 1,5-pentanediisocyanate
By using nitrogen high-temperature stripping technology and self-recovery distillation system in the production process of 1,5-pentadiisocyanate, the problem of high hydrolyzed chlorine content is solved, and the product performance is improved, production simplification and energy saving is achieved.
Patent Information
- Application Number
- CN202421266417.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-06-05
- Publication Date
- 2025-04-04
- Estimated Expiration
- 2034-06-05
AI Technical Summary
The prior art is difficult to effectively reduce the hydrolyzed chlorine content of 1,5-pentadiisocyanate, resulting in a decrease in product performance and increased production difficulty.
Using nitrogen high-temperature stripping technology, nitrogen is introduced during the thermal actinization process, hydrogen chloride and phosgene are purged and discharged by-products such as hydrogen chloride and phosgene. Combined with a self-recovery distillation system, energy balance is maintained through a compressor to achieve the separation of components.
Effectively reduce the hydrolyzed chlorine content of 1,5-pentadiisocyanate to 100 ppm, simplify operation, save energy, is suitable for large-scale industrial production, and has strong practicality and promotion.
Smart Images
Figure CN222709615U_ABST
Abstract
Description
Technical Field
[0001] The utility model belongs to the field of chemical technology equipment, and in particular relates to a system for reducing chlorine in the hydrolysis of 1,5-pentanediisocyanate. Background Art
[0002] As an important organic synthesis intermediate, isocyanate is widely used in polyurethane, coatings, dyes, thermal insulation materials and medicine. Traditional aromatic isocyanates contain aromatic groups, which are easily oxidized to form quinones, resulting in yellowing and poor weather resistance of the obtained polyurethane coatings and other products. Therefore, it is urgent to study new aliphatic diisocyanates with higher activity and better performance. 1,5-pentamethylene diisocyanate (PDI), also known as pentamethylene diisocyanate, is a new type of aliphatic diisocyanate. Its products and related derivatives have excellent performance. Compared with HDI (hexamethylene diisocyanate), it has higher activity. It can not only replace HDI in HDI and its derivatives, but also has better performance and more market prospects.
[0003] The hydrolyzed chlorine content is an important indicator of PDI product quality, because a high hydrolyzed chlorine content will not only increase the difficulty of subsequent purification, but also lead to problems such as decreased reaction activity, darker product color, and decreased performance. Since hydrolyzed chlorine has an adverse effect on the performance of PDI products, the hydrolyzed chlorine content needs to be reduced during the production process. Summary of the invention
[0004] The utility model aims to overcome the defects of the prior art and provide a system for reducing the hydrolysis chlorine of 1,5-pentanediisocyanate.
[0005] To achieve the above-mentioned purpose, the technical solution adopted by the utility model is: a system for reducing the hydrolysis chlorine of 1,5-pentanediisocyanate, including a reactor, characterized in that: the reactor is connected to a nitrogen pipe, the gas phase outlet at the top of the reactor is connected to a No. 1 heat exchanger through a gas phase pipe, the first gas phase pipe at the top of the No. 1 heat exchanger is connected to a phosgene absorption system, and the first liquid phase pipe at the bottom of the No. 1 heat exchanger returns to connect to the reactor; the photochemical liquid outlet pipe at the bottom of the reactor is connected to a distillation tower, the liquid phase reflux pipe at the bottom of the distillation tower is connected to a storage tank, the outlet pipe at the bottom of the storage tank is connected to a light component extraction pipe through a centrifugal pump, the light component extraction pipe is connected to a No. 2 heat exchanger, the second liquid phase pipe at the top of the No. 2 heat exchanger is connected to the reactor, the gas phase pipe at the top of the distillation tower is connected to a compressor, the exhaust pipe of the compressor is connected to a No. 3 heat exchanger, the third liquid phase pipe of the No. 3 heat exchanger is connected to the storage tank, and the third gas phase pipe of the No. 3 heat exchanger is connected to the No. 2 heat exchanger; the non-condensable gas pipe of the No. 3 heat exchanger is connected to a tail gas absorption device.
[0006] The pipeline at the front section of the light component extraction pipe near the centrifugal pump outlet is connected to the heavy component extraction pipe; the third liquid phase pipe is connected to the solvent recovery pipe, and the distillation tower is connected to the product extraction pipe. The heavy component extraction pipe, the solvent recovery pipe and the product extraction pipe are all provided with control valves.
[0007] The reactor is provided with a stirrer for uniformly mixing materials.
[0008] A gas distributor for evenly distributing nitrogen is arranged in the nitrogen pipe.
[0009] The principle of the utility model is: using nitrogen high-temperature stripping, introducing nitrogen in the process of thermal photochemical reaction, blowing and discharging by-products such as hydrogen chloride and phosgene generated in the process of generating 1,5-pentanediisocyanate to the phosgene absorption system, reducing the content of hydrolyzed chlorine (HC); the self-heat recovery distillation system uses a compressor to maintain the energy balance of the system, achieves energy saving through the latent heat of vaporization of the tower top steam, and is used for the separation of components with similar boiling points.
[0010] The utility model has the following beneficial effects: nitrogen stripping and dehydration are utilized, the operation is simple, and the hydrolyzed chlorine content in the synthesized 1,5-pentanediisocyanate can be effectively reduced to 100 ppm; the PDI product and by-products with similar boiling points are separated through a self-heating distillation system, and a large amount of thermal utilities are no longer required to heat the bottom liquid and preheat the feed, and a large amount of utilities are also not required to condense the top steam, and only the electric energy for driving the compressor to do work and a small amount of cooling water are required; the operation process is simple, suitable for large-scale industrial production, and has strong practicality and promotion in the same industry. BRIEF DESCRIPTION OF THE DRAWINGS
[0011] Figure 1 It is a schematic diagram of the utility model.
[0012] In the figure: 1-reactor, 2-heat exchanger No. 1, 3-distillation tower, 4-storage tank, 5-heat exchanger No. 2, 6-heat exchanger No. 3, 7-compressor; A-nitrogen pipe, B-gas phase pipe, C1-first gas phase pipe, D1-first liquid phase pipe, D2-second liquid phase pipe, C3-third gas phase pipe, D3-third liquid phase pipe, H-liquid phase reflux pipe, L-photochemical liquid outlet pipe, K-light component production pipe, M-heavy component production pipe, N-non-condensable gas pipe, R-solvent recovery pipe, S-product production pipe. DETAILED DESCRIPTION
[0013] The present invention is further described in detail below in conjunction with embodiments. The embodiments are only used to explain the present invention and are not used to limit the scope of the present invention.
[0014] Example 1, see Figure 1A system for reducing chlorine in the hydrolysis of 1,5-pentanediisocyanate, comprising a reactor 1, characterized in that: the reactor 1 is connected to a nitrogen pipe A, and a gas distributor for uniformly distributing nitrogen is arranged in the nitrogen pipe A; the gas phase outlet at the top of the reactor 1 is connected to a No. 1 heat exchanger 2 through a gas phase pipe B, the first gas phase pipe C1 at the top of the No. 1 heat exchanger 2 is connected to a phosgene absorption system, and the first liquid phase pipe D1 at the bottom of the No. 1 heat exchanger 2 is returned and connected to the reactor 1; the photochemical liquid outlet pipe L at the bottom of the reactor 1 is connected to a distillation tower 3, and the distillation tower 3 is connected to the distillation tower 3. The liquid phase reflux pipe H at the bottom is connected to the storage tank 4, the liquid outlet pipe at the bottom of the storage tank 4 is connected to the light component extraction pipe K through a centrifugal pump, the light component extraction pipe K is connected to the No. 2 heat exchanger 5, the second liquid phase pipe D2 at the top of the No. 2 heat exchanger 5 is connected to the bottom of the distillation tower 3, the gas phase pipe at the top of the distillation tower 3 is connected to the compressor 7, the exhaust pipe of the compressor 7 is connected to the No. 3 heat exchanger 6, the third liquid phase pipe D3 of the No. 3 heat exchanger 6 is connected to the storage tank 4, the third gas phase pipe C3 of the No. 3 heat exchanger 6 is connected to the No. 2 heat exchanger 5; the non-condensable gas pipe N of the No. 3 heat exchanger 6 is connected to the tail gas absorption device.
[0015] The pipeline in the front section of the light component extraction pipe K near the outlet of the centrifugal pump is connected to the heavy component extraction pipe M; the third liquid phase pipe D3 is connected to the solvent recovery pipe R, and the distillation tower 3 is connected to the product extraction pipe S. The heavy component extraction pipe M, the solvent recovery pipe R and the product extraction pipe S are all provided with control valves.
[0016] The reactor 1 is provided with a stirrer for uniformly mixing materials.
[0017] Working process: Stir and heat the mixed materials (diaminoformyl chloride, phosgene, o-dichlorobenzene, pentamethylenediamine) in reactor 1 to 140-155°C, open the valve on nitrogen pipe A, introduce a proper amount of nitrogen into reactor 1, and the gaseous material enters heat exchanger 2 No. 1 from the top of reactor 1 through gas phase pipe B. Repeat the cycle for 12 hours. After sampling and analysis are qualified, stop the reaction.
[0018] The photochemical liquid after the reaction in reactor 1 is added to the distillation tower 3 through the photochemical liquid outlet pipe L. The photochemical liquid at the bottom of the distillation tower 3 flows into the storage tank 4 through the liquid phase reflux pipe H. The photochemical liquid in the storage tank 4 enters the centrifugal pump through the outlet pipe. The centrifugal pump extracts the heavy component through the heavy component extraction pipe M and barrels it. The light component enters the second heat exchanger 5 through the light component extraction pipe K and is heated to 180-220℃. After the second heat exchanger 5 is preheated, the photochemical liquid is connected to the bottom of the distillation tower 3 through the second liquid phase pipe D2. The photochemical liquid in the distillation tower 3 is separated by plates, and the light component The condensate enters the compressor 7 through the gas phase pipe, the compressor 7 performs heat exchange and transfers the heat to the No. 3 heat exchanger 6 through the gas phase pipe, the No. 3 heat exchanger 6 transfers the condensate to the storage tank 4 through the third liquid phase pipe D3 for circular distillation, and the solvent is barreled and recovered through the solvent recovery pipe R, the No. 3 heat exchanger 6 transfers the heat to the No. 2 heat exchanger 5 through the third gas phase pipe C3; the non-condensable gas of the No. 3 heat exchanger 6 is discharged to the tail gas absorption device through the non-condensable gas pipe N, and the distillation is repeated. When the reflux rate of the product extraction pipe S reaches 4500-5000 Kg / h, the sampling control valve is opened to barrel the PDI product, and the PDI mass fraction of the sample taken for sampling and analysis is qualified (≥95.5%).
[0019] Although the embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the above embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.
Claims
1. A system for reducing chlorine in the hydrolysis of 1,5-pentanediisocyanate, comprising a reaction kettle (1), characterized in that: The reactor (1) is connected to a nitrogen pipe (A); the gas phase outlet at the top of the reactor (1) is connected to the first heat exchanger (2) through a gas phase pipe (B); the first gas phase pipe (C1) at the top of the first heat exchanger (2) is connected to the phosgene absorption system; the first liquid phase pipe (D1) at the bottom of the first heat exchanger (2) is returned to the reactor (1); the photochemical liquid outlet pipe (L) at the bottom of the reactor (1) is connected to the distillation tower (3); the liquid phase reflux pipe (H) at the bottom of the distillation tower (3) is connected to the storage tank (4); the outlet pipe at the bottom of the storage tank (4) is connected to the light gas absorption system through a centrifugal pump. The component extraction pipe (K) and the light component extraction pipe (K) are connected to the No. 2 heat exchanger (5); the second liquid phase pipe (D2) at the top of the No. 2 heat exchanger (5) is connected to the bottom of the distillation tower (3); the gas phase pipe at the top of the distillation tower (3) is connected to the compressor (7); the exhaust pipe of the compressor (7) is connected to the No. 3 heat exchanger (6); the third liquid phase pipe (D3) of the No. 3 heat exchanger (6) is connected to the storage tank (4); the third gas phase pipe (C3) of the No. 3 heat exchanger (6) is connected to the No. 2 heat exchanger (5); and the non-condensable gas pipe (N) of the No. 3 heat exchanger (6) is connected to the tail gas absorption device.
2. A system for reducing hydrolysis chlorine of 1,5-pentanediisocyanate according to claim 1, characterized in that: A pipeline at the front section of the light component extraction pipe (K) near the outlet of the centrifugal pump is connected to a heavy component extraction pipe (M); the third liquid phase pipe (D3) is connected to a solvent recovery pipe (R), and the distillation tower (3) is connected to a product extraction pipe (S); and control valves are provided on the heavy component extraction pipe (M), the solvent recovery pipe (R) and the product extraction pipe (S).
3. A system for reducing hydrolysis chlorine of 1,5-pentanediisocyanate according to claim 1, characterized in that: The reaction kettle (1) is provided with a stirrer for uniformly mixing materials.
4. A system for reducing hydrolysis chlorine of 1,5-pentanediisocyanate according to claim 1, characterized in that: A gas distributor for evenly distributing nitrogen is provided in the nitrogen pipe (A).