Constant temperature control system for AKD (Alkyl Ketene Dimer) production
By designing a constant temperature control system, the problems of insufficient temperature in the early stage of AKD production and temperature instability caused by exothermic reactions were solved, achieving precise temperature control inside the reactor and ensuring the smooth progress of the AKD reaction.
Patent Information
- Application Number
- CN202423117480.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-17
- Publication Date
- 2025-11-14
- Estimated Expiration
- 2034-12-17
AI Technical Summary
In the current AKD production process, the triethylamine temperature is insufficient in the early stage of the reaction, which affects the reaction process. In addition, the exothermic reaction process leads to temperature instability, which also affects the smooth progress of the reaction.
A constant temperature control system was designed, including a temperature regulating circulation pipeline, a temperature regulating pipeline, and a temperature regulating return water pipeline. Through the combination of heat exchangers, pumps, temperature detection units, and control valves, precise control of the temperature inside the reactor is achieved.
It effectively solves the problems of insufficient temperature in the early stage of reaction and temperature fluctuation caused by exothermic reaction, ensuring that the temperature inside the reactor is stable within a suitable range and promoting the smooth progress of the AKD reaction.
Smart Images
Figure CN223552037U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of alkyl ketene dimer processing technology, specifically a constant temperature control system for AKD production. Background Technology
[0002] Alkyl ketene dimer (AKD) is an unsaturated lactone that can be used as an alkaline sizing agent in papermaking. It is primarily used as an internal sizing agent for coated paper, copy paper, archival paper, dictionary paper, and high-quality writing paper. The sizing pH value can reach approximately 8.0, and it is widely used both domestically and internationally.
[0003] There are two main processes for AKD synthesis: one is the solvent-based process, with the main raw materials being triethylamine, fatty acid acyl chloride, and toluene, where toluene is the solvent. In the synthesis reaction, due to the presence of the solvent toluene, the materials have good fluidity and low viscosity, and a stirred mixing reaction mode is generally adopted.
[0004] Another method is the solvent-free process, with triethylamine and fatty acid acyl chloride as the main raw materials. In the solvent-free synthesis of the papermaking additive AKD, the material viscosity is high in the later stages of the reaction, and it contains fine triethylamine hydrochloride solid particles. At a temperature T=65℃, the material viscosity can reach 130,000 mPa·s. After the reaction, the triethylamine hydrochloride solid particles in the AKD product need to be dissolved in the solution to achieve stratification of AKD in the triethylamine hydrochloride aqueous solution, thus obtaining a high-purity AKD product. Finally, the AKD undergoes vacuum dehydration to remove volatile impurities. The internal medium of the reactor must not come into contact with external air, which requires a highly airtight seal to prevent leakage of the internal medium to the outside or contact between external air and the internal medium.
[0005] However, the triethylamine temperature is low in the early stage of AKD synthesis, and the newly formed AKD is below the melting point and exists in solid form, which affects the reaction. During the reaction, the exothermic condensation reaction of acyl chloride causes the reaction temperature to rise, thus affecting the smooth progress of the AKD reaction.
[0006] To solve this problem, a constant temperature control system is needed to meet the production requirements of the process, based on the characteristics of the process. Utility Model Content
[0007] The technical problem to be solved by this invention is to address the shortcomings of the existing technology by providing a constant temperature control system for AKD production that can solve the problem of insufficient triethylamine temperature in the early stage of the reaction and the problem of exothermic reaction.
[0008] The technical problem to be solved by this utility model is achieved through the following technical solution: a constant temperature control system for AKD production, the constant temperature control system comprising;
[0009] The temperature-regulating circulation pipeline includes a heat exchanger inlet circulation water pipeline, a heat exchanger outlet circulation water pipeline and a high-level makeup water tank. A heat exchanger is installed between the heat exchanger inlet circulation water pipeline and the heat exchanger outlet circulation water pipeline. The outlet end of the high-level makeup water tank is connected to the heat exchanger outlet circulation water pipeline. A pump I is installed on the heat exchanger outlet circulation water pipeline.
[0010] The temperature control pipeline includes a temperature control water supply pipeline, a user area temperature control water supply pipeline, and a user area temperature control water return pipeline. The inlet end of the water supply pipeline is connected to the circulating water pipeline at the heat exchanger outlet. One end of the user area temperature control water supply pipeline is connected to the outlet end of the water supply pipeline, and the other end is connected to the constant temperature heating water jacket on the outer wall of the reactor for preparing alkyl ketene dimers. Pump II is installed on the user area temperature control water supply pipeline. One end of the user area temperature control water return pipeline is connected to the outlet end of the constant temperature heating water jacket, and the other end is connected to the outlet end of the temperature control water supply pipeline. A check valve is installed between the outlet ends of the user area temperature control water return pipeline and the water supply pipeline to prevent water at the outlet end of the water supply pipeline from directly entering the user area temperature control water return pipeline.
[0011] The temperature-regulating return water pipeline has one end connected to the temperature-regulating return water pipeline in the user area, and the other end connected to the pipeline between the high-level water supply tank and the circulating water pipeline of the heat exchanger. A control valve is installed on the temperature-regulating return water pipeline.
[0012] The technical problem to be solved by this utility model can also be achieved through the following technical solution: the constant temperature control system for AKD production described above, wherein the top of the high-level water supply tank is equipped with an overflow pipe and a deionized water supply pipe.
[0013] The technical problem to be solved by this utility model can also be achieved through the following technical solution: the constant temperature control system for AKD production described above is provided with a secondary pipeline on both the heat exchanger inlet circulating water pipeline and the heat exchanger outlet circulating water pipeline, and the heat exchanger or pump I is provided on the secondary pipeline.
[0014] The technical problem to be solved by this utility model can also be achieved through the following technical solution: the constant temperature control system for AKD production described above, wherein an exhaust pipe is installed on the user area temperature-regulating water return pipe, and an exhaust valve is installed on the exhaust pipe.
[0015] The technical problem to be solved by this utility model can also be achieved through the following technical solution: the constant temperature control system for AKD production described above has a temperature detection unit installed on the temperature-regulating water supply pipeline in the user area, and the temperature detection unit is interlocked with the control valve.
[0016] Compared with the prior art, the beneficial technical effects of this utility model are as follows: In the initial stage of the reaction of the alkyl ketene dimer in the reactor, the reaction temperature needs to reach the melting point of the alkyl ketene dimer. Therefore, the temperature control pipeline can supply hot water to the temperature control circulation pipeline to increase the temperature in the reactor, which is conducive to promoting the normal reaction of the alkyl ketene dimer in the reactor. In addition, since the alkyl ketene dimer releases heat during the reaction process, when the temperature detection unit on the temperature control pipeline detects that the temperature in the reactor has reached the target temperature, it opens the control valve to discharge the hot water in the user area temperature control water supply pipeline and the user area temperature control water return pipeline, so that the temperature control circulation pipeline can supply warm water to the temperature control pipeline. Attached Figure Description
[0017] Figure 1 This is a schematic diagram of the pipeline connection of this utility model.
[0018] Attached reference numerals: 1. Heat exchanger inlet circulating water pipe; 2. Heat exchanger outlet circulating water pipe; 3. High-level makeup water tank; 4. Overflow pipe; 5. Deionized water makeup water pipe; 6. Heat exchanger; 7. Pump I; 8. Temperature-regulating water supply pipe; 9. User area temperature-regulating water supply pipe; 10. User area temperature-regulating water return pipe; 11. Pump II; 12. Constant temperature heating water jacket; 13. Check valve; 14. Exhaust pipe; 15. Temperature detection unit; 16. Control valve; 17. Temperature-regulating return water pipe. Detailed Implementation
[0019] The specific technical solutions of this utility model are further described below with reference to the accompanying drawings, so as to enable those skilled in the art to further understand this utility model, without constituting a limitation on its rights.
[0020] Example 1, referring to Figure 1 A temperature control system for AKD production, the temperature control system comprising;
[0021] The temperature-regulating circulation pipeline includes a heat exchanger inlet circulating water pipeline 1, a heat exchanger outlet circulating water pipeline 2, and a high-level makeup water tank 3. An overflow pipe 4 and a deionized water makeup water pipe 5 are installed on the top of the high-level makeup water tank 3. A heat exchanger 6 is installed between the heat exchanger inlet circulating water pipeline 1 and the heat exchanger outlet circulating water pipeline 2. The outlet end of the high-level makeup water tank 3 is connected to the heat exchanger outlet circulating water pipeline 2. A pump I 7 is installed on the heat exchanger outlet circulating water pipeline 2.
[0022] Both the heat exchanger inlet circulating water pipe 1 and the heat exchanger outlet circulating water pipe 2 are equipped with secondary pipes, and the heat exchanger 6 or pump I 7 are located on the secondary pipes.
[0023] The temperature control pipeline includes a temperature control water supply pipeline 8, a user area temperature control water supply pipeline 9, and a user area temperature control water return pipeline 10. The inlet end of the supply pipeline is connected to the circulating water pipeline 2 at the heat exchanger outlet. One end of the user area temperature control water supply pipeline 9 is connected to the outlet end of the supply pipeline, and the other end is connected to the constant temperature heating water jacket on the outer wall of the reactor for preparing alkyl ketene dimers. A pump II 11 is installed on the user area temperature control water supply pipeline 9. One end of the return water pipe 10 is connected to the outlet end of the constant temperature heating water jacket 12, and the other end is connected to the outlet end of the temperature-regulating water supply pipe. A check valve 13 is installed between the outlet ends of the user area temperature-regulating water return pipe 10 and the supply pipe to prevent water at the outlet end of the supply pipe from directly entering the user area temperature-regulating water return pipe 10. An exhaust pipe 14 is installed on the user area temperature-regulating water return pipe 10, and an exhaust valve is installed on the exhaust pipe 14.
[0024] A temperature detection unit 15 is installed on the temperature-controlled water supply pipeline 9 in the user area. The temperature detection unit 15 is interlocked with the control valve 16.
[0025] The temperature-regulating return water pipeline 17 has one end connected to the temperature-regulating return water pipeline 10 in the user area, and the other end connected to the pipeline between the high-level water supply tank 3 and the heat exchanger outlet circulating water pipeline 2 through a pipe. A control valve 16 is installed on the temperature-regulating return water pipeline 17.
[0026] The operating principle of the constant temperature control system used in AKD production in Example 1 is as follows:
[0027] In the initial stage of the reaction, the temperature of the alkyl ketene dimer in the reactor is not yet at the ideal melting temperature. At this time, the temperature of the temperature regulating water is higher than the temperature of the reaction system. The temperature regulating circulation pipeline supplies hot water to the temperature regulating pipeline. At this time, pump II11 is started, so that the supplied hot water circulates between the temperature regulating inlet pipeline 9 and the temperature regulating outlet pipeline 10, thereby increasing the temperature of the alkyl ketene dimer in the reactor.
[0028] It should be noted that because the circulating water between the temperature-controlled inlet pipe 9 and the temperature-controlled outlet pipe 10 is constantly circulating and exchanging heat, the temperature of this part of the hot water will decrease due to continuous heat exchange in the early stage of the reaction. Therefore, the control valve 16 will open, thereby discharging water with a temperature lower than the ideal melting temperature, and allowing the temperature-controlled circulation pipe to circulate and supply new hot water into the temperature-controlled pipe.
[0029] During this process, when the alkyl ketene dimer in the reactor is heated to the melting temperature of the reaction, the continued synthesis of the alkyl ketene dimer will release heat during the reaction. Therefore, control valve 16 will open, thereby discharging water at a temperature higher than the ideal temperature, and allowing the temperature-regulating circulation pipeline to circulate and supply new temperature-regulating water into the temperature-regulating pipeline. At this time, the temperature-regulating circulation pipeline can supply temperature-regulating water at a temperature lower than that of the reaction system to the temperature-regulating pipeline in the user area, thereby achieving constant temperature control of the alkyl ketene dimer in the reactor.
Claims
1. A constant temperature control system for AKD production, characterized in that: The constant temperature control system includes: The temperature-regulating circulation pipeline includes a heat exchanger inlet circulation water pipeline, a heat exchanger outlet circulation water pipeline and a high-level makeup water tank. A heat exchanger is installed between the heat exchanger inlet circulation water pipeline and the heat exchanger outlet circulation water pipeline. The outlet end of the high-level makeup water tank is connected to the heat exchanger outlet circulation water pipeline. A pump I is installed on the heat exchanger outlet circulation water pipeline. The temperature control pipeline includes a temperature control water supply pipeline, a user area temperature control water supply pipeline, and a user area temperature control water return pipeline. The inlet end of the water supply pipeline is connected to the circulating water pipeline at the heat exchanger outlet. One end of the user area temperature control water supply pipeline is connected to the outlet end of the water supply pipeline, and the other end is connected to the constant temperature heating water jacket on the outer wall of the reactor for preparing alkyl ketene dimers. Pump II is installed on the user area temperature control water supply pipeline. One end of the user area temperature control water return pipeline is connected to the outlet end of the constant temperature heating water jacket, and the other end is connected to the outlet end of the temperature control water supply pipeline. A check valve is installed between the outlet ends of the user area temperature control water return pipeline and the water supply pipeline to prevent water at the outlet end of the water supply pipeline from directly entering the user area temperature control water return pipeline. The temperature-regulating return water pipeline has one end connected to the temperature-regulating return water pipeline in the user area, and the other end connected to the pipeline between the high-level water supply tank and the circulating water pipeline of the heat exchanger. A control valve is installed on the temperature-regulating return water pipeline.
2. The constant temperature control system for AKD production according to claim 1, characterized in that: The top of the elevated water tank is equipped with an overflow pipe and a deionized water supply pipe.
3. The constant temperature control system for AKD production according to claim 1, characterized in that: Both the inlet and outlet circulating water pipes of the heat exchanger are equipped with secondary pipes, and the heat exchanger or pump I is located on the secondary pipes.
4. A constant temperature control system for AKD production according to claim 1, characterized in that: The user area temperature-regulating water return pipe is equipped with an exhaust pipe, and an exhaust valve is installed on the exhaust pipe.
5. A constant temperature control system for AKD production according to claim 1, characterized in that: A temperature detection unit is installed on the temperature-controlled water supply pipeline in the user area, and the temperature detection unit is interlocked with the control valve.