An ethoxylation reaction system heat exchange device and a heat exchange method thereof

Abstract

The application belongs to the technical field of surfactant application, and relates to an ethoxylation reaction system heat exchange device and an ethoxylation reaction system heat exchange method. A raw material alcohol head heater (1) is internally provided with a pressurized water winding pipe (2) and a steam winding pipe (3). The pressurized water winding pipe (2) is connected with a first pipeline (4) at an inlet, the first pipeline (4) is connected with a first heat exchanger (5), the first heat exchanger (5) is connected with a reaction heat delivery pipeline (6) of an ethoxylation reaction system, and the first heat exchanger (5) is connected with an outlet of the pressurized water winding pipe (2) through a second pipeline (7). The heat exchange mode of the ethoxylation reaction system heat exchange device includes a segmented heating mode and a full-range steam heating mode. The device and the method can realize double-pipeline double-medium isolation delivery and switching control, effectively meet the heating mode switching of the first start and normal production process of the ethoxylation reaction system, and realize efficient utilization of waste heat in stages.

Description

Technical Field

[0001] This invention belongs to the field of surfactant application technology, and more specifically, relates to a heat exchange device for an ethoxylation reaction system. This invention also relates to a heat exchange method for an ethoxylation reaction system. Background Technology

[0002] In the production of ethoxylated surfactant products, the core process involves polymerization using ethylene oxide or propylene oxide as raw materials. This polymerization reaction is a typical strongly exothermic reaction, continuously releasing a large amount of heat. If this heat is not removed from the reaction system in a timely and effective manner, it can lead to temperature runaway, affecting key quality indicators such as molecular weight distribution and purity of the product. Furthermore, excessively high temperatures may cause the decomposition and leakage of the raw materials ethylene oxide / propylene oxide, posing safety hazards. Therefore, maintaining a stable reaction system temperature while simultaneously achieving the rational recovery and utilization of reaction heat is a crucial aspect of the ethoxylation production process and an important way to reduce energy consumption and improve production safety.

[0003] The production of surfactant products has extremely stringent requirements regarding the moisture content of the raw material alcohol heads. Even trace amounts of moisture can severely impact the initiation efficiency of the polymerization reaction, leading to substandard product quality and increased side reactions. Therefore, the raw material alcohol heads must undergo a rigorous pretreatment and dehydration process before entering the polymerization reaction. Currently, the industry's raw material pretreatment processes for surfactant products all use steam as the sole heating medium to complete the entire process of raw material heating, vacuum dehydration, and reaction initiation heating. While this heating method eliminates the need to consider medium isolation, it consumes a huge amount of steam, resulting in high energy consumption in product production. This contradicts the current trend of energy conservation, emission reduction, and green low-carbon development in industrial production and also increases production costs for enterprises.

[0004] Existing technology includes a device for recovering and utilizing the heat of ethoxylation reaction, published under publication number "203635198U". This technology discloses a device for recovering and utilizing the heat of ethoxylation reaction. It includes a circulating heat exchanger connected to the ethoxylation reaction system, which comprises at least two ethoxylation reaction units. The reaction collector of each ethoxylation reaction unit is connected to the circulating heat exchanger. The circulating heat exchanger is also connected to a hot oil system and a cold oil system. This device and method for recovering and utilizing the heat of ethoxylation reaction overcomes the difficulties in recovering the exothermic heat from intermittent reactions by integrating and optimizing the hot oil / cold oil system process and rationally arranging production. It achieves near-continuous and stable release of the heat of ethylene oxide reaction and utilizes the heat transfer medium to directly apply the reaction heat to other locations requiring low-temperature heat sources, thus fully and rationally utilizing the reaction heat while reducing circulating water consumption and effectively lowering production energy consumption. However, this technology does not address the technical problems and solutions of this application. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a heat exchange device for an ethoxylation reaction system that can realize dual-pipeline dual-medium isolated delivery and switching control, effectively meet the heating mode switching of the ethoxylation reaction system during the initial start-up and normal production process, realize the efficient utilization of waste heat in a cascade manner, and meet the requirements of energy saving, consumption reduction, green and low carbon emissions.

[0006] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows: This invention relates to a heat exchange device for an ethoxylation reaction system. The raw material alcohol head heater is internally equipped with a pressurized water coil and a steam coil. The inlet of the pressurized water coil is connected to a first pipeline, which in turn connects to a first heat exchanger. The first heat exchanger is simultaneously connected to the reaction heat transport pipeline of the ethoxylation reaction system. The first heat exchanger is connected to the outlet of the pressurized water coil via a second pipeline. The raw material alcohol head heater is equipped with a raw material inlet and a raw material outlet. The heat exchange mode of the ethoxylation reaction system heat exchange device includes a segmented heating mode and a full-process steam heating mode.

[0007] A second heat exchanger is installed on the second pipeline, and the second heat exchanger is also connected to a third pipeline. One end of the third pipeline is connected to the hot water user inlet, and the other end of the third pipeline is connected to the hot water storage tank outlet. One end of the fourth pipeline is connected to the hot water user outlet, and the other end of the fourth pipeline is connected to the hot water storage tank inlet.

[0008] The first pipeline and the second pipeline are connected to a fifth pipeline. One end of the fifth pipeline is connected to the first pipeline position between the first heat exchanger and the pressurized water coil, and the other end of the fifth pipeline is connected to the fourth pipeline position between the second heat exchanger and the raw material alcohol head heater.

[0009] The pressurized water coil is a spiral tube structure located inside the raw material alcohol head heater, and the steam coil is also a spiral tube structure located inside the raw material alcohol head heater.

[0010] The steam coil inlet is connected to the steam supply pipeline, and the steam coil outlet is connected to the condensate discharge pipeline. A steam input solenoid valve is installed near the steam coil inlet in the steam supply pipeline, and a steam output solenoid valve is installed near the steam coil outlet in the condensate discharge pipeline.

[0011] A pressurized water input solenoid valve is installed on the first pipeline near the inlet of the pressurized water loop, and a pressurized water output solenoid valve is installed on the second pipeline near the outlet of the pressurized water loop.

[0012] The aforementioned reaction heat transport pipeline includes a reaction heat input pipeline and a reaction heat output pipeline.

[0013] A pressurized water pump is installed on the first pipeline between the second heat exchanger and the first heat exchanger. The first pipeline is connected to a pressurized water expansion tank and connects the first heat exchanger to the second heat exchanger.

[0014] When the ethoxylation reaction system is started for the first time, the raw material alcohol head tank is switched to full steam heating mode: no reaction heat is generated in the ethoxylation reaction system, no reaction heat is generated in the reaction heat delivery pipeline, the pressurized water inlet solenoid valve and pressurized water outlet solenoid valve of the pressurized water coil are closed, the steam inlet solenoid valve and steam outlet solenoid valve are opened, and steam enters the steam coil and the raw material alcohol head heater for heat exchange, thereby completing the entire process of preheating, dehydration and heating to the reaction initiation temperature of the raw material.

[0015] When the ethoxylation reaction system starts up and the reaction heat transmission pipeline generates reaction heat, it enters normal production mode and proceeds with the preparation of the next batch of raw materials. At this time, the raw material alcohol head tank is switched to segmented heating mode: the reaction heat generated by the ethoxylation reaction system is sent to the first heat exchanger and the first pipeline for heat exchange through the reaction heat transmission pipeline. The temperature of the pressurized water in the first pipeline rises, and the pressurized water inlet solenoid valve and pressurized water outlet solenoid valve of the pressurized water loop open. At this time, the fifth pipeline solenoid valve closes, and the steam inlet solenoid valve and steam outlet solenoid valve close. Pressurized water flows through the second pipeline and the first... The second heat exchanger returns to the first pipeline to complete a closed-loop circulation. Pressurized water exchanges heat with the raw material inside the raw material alcohol head heater, raising the raw material to the first-stage temperature, i.e., the raw material dehydration temperature. Then, the first-stage temperature is precisely controlled and maintained by the temperature regulating valve to complete the raw material dehydration process. Then, the pressurized water inlet solenoid valve and pressurized water outlet solenoid valve of the pressurized water loop are closed, while the steam inlet solenoid valve and steam outlet solenoid valve are opened. The steam exchanges heat with the raw material inside the raw material alcohol head heater, raising the raw material to the second-stage temperature, i.e., the reaction initiation temperature. After that, the raw material is transported to the ethoxylation reaction system to participate in the reaction.

[0016] When the ethoxylation reaction system is started and the reaction heat is generated in the reaction heat transport pipeline, it enters normal production conditions. When the raw material alcohol head heater has no heat exchange requirement, the fifth pipeline solenoid valve opens, the pressurized water inlet solenoid valve and the pressurized water outlet solenoid valve of the pressurized water winding pipe close, and the steam inlet solenoid valve and the steam outlet solenoid valve close. The pressurized water in the first pipeline flows back to the second pipeline through the fifth pipeline. The pressurized water in the second pipeline simultaneously exchanges heat with the water in the third pipeline through the second heat exchanger, heating the water in the third pipeline. The heated water in the third pipeline is supplied to hot water users and returns to the hot water storage tank through the fourth pipeline.

[0017] This invention also relates to a heat exchange method for an ethoxylation reaction system that enables dual-pipeline, dual-medium isolated transport and switching control, effectively meeting the heating mode switching requirements of the initial start-up and normal production processes of the ethoxylation reaction system, achieving efficient utilization of waste heat in a cascade manner, and meeting the requirements of energy conservation, emission reduction, and green low-carbon development. The steps of the heat exchange method are as follows: S1. When the ethoxylation reaction system is started for the first time, the ethoxylation reaction system switches to full steam heating mode: no reaction heat is generated in the ethoxylation reaction system, no reaction heat is generated in the reaction heat delivery pipeline, the pressurized water inlet solenoid valve and pressurized water outlet solenoid valve of the pressurized water coil are closed, the steam inlet solenoid valve and steam outlet solenoid valve are opened, and steam enters the steam coil and the raw material alcohol head heater for raw material heat exchange, thereby completing the entire process of raw material preheating, dehydration and heating to the reaction initiation temperature in sequence; S2. When the reaction heat is generated in the reaction heat conveying pipeline after the ethoxylation reaction system is started, it enters the normal production condition and the ethoxylation reaction system switches to the segmented heating mode: the reaction heat generated by the ethoxylation reaction system is sent to the first heat exchanger and the first pipeline for heat exchange through the reaction heat conveying pipeline. The temperature of the pressurized water in the first pipeline rises, the pressurized water inlet solenoid valve and the pressurized water outlet solenoid valve of the pressurized water loop open, the steam inlet solenoid valve and the steam outlet solenoid valve close, the pressurized water circulates, and the pressurized water exchanges heat with the raw material inside the raw material alcohol head heater, raising the raw material to the first stage temperature; S3. The pressurized water inlet solenoid valve and pressurized water outlet solenoid valve of the pressurized water coil are closed, and the steam inlet solenoid valve and steam outlet solenoid valve are opened. The steam exchanges heat with the raw material inside the raw material alcohol head heater, raising the raw material to the second stage temperature, i.e. the reaction initiation temperature. After that, the raw material is transported to the ethoxylation reaction system to participate in the reaction.

[0018] S4. When the steam input solenoid valve and the steam output solenoid valve are open, the pressurized water input solenoid valve and the pressurized water output solenoid valve of the pressurized water loop are closed. The pressurized water in the second pipeline flows back to the second pipeline through the fifth pipeline. The pressurized water in the second pipeline 7 simultaneously exchanges heat with the water in the second heat exchanger and the water in the third pipeline, heating the water in the third pipeline. The heated water in the third pipeline is then supplied to hot water users.

[0019] The working principle and beneficial effects of the technical solution adopted in this invention are as follows: The heat exchange device for the ethoxylation reaction system described in this invention is structurally configured such that a pressurized water coil and a steam coil are installed inside the raw material alcohol head heater. These are separate, isolated pipelines, both passing through the raw material alcohol head heater. The inlet of the pressurized water coil is connected to a first pipeline, which in turn connects to a first heat exchanger. This first heat exchanger is also connected to the reaction heat transport pipeline of the ethoxylation reaction system. Heat exchange is achieved between the first heat exchanger and the reaction heat transport pipeline, allowing pressurized hot water to be transported through the first pipeline to the pressurized water coil. The heat from the pressurized water coil is used to heat the material in the raw material alcohol head heater, raising its temperature. The first heat exchanger is connected to the outlet of the pressurized water coil through a second pipeline. The pressurized water that has undergone heat exchange in the raw material alcohol head heater flows out through the second pipeline and re-enters the first heat exchanger to absorb heat, thus supplying pressurized hot water again and achieving cyclic heat exchange. The steam coil passes through the raw material alcohol head heater. The steam coil inlet is connected to the steam supply pipeline, which supplies high-temperature steam. As the high-temperature steam passes through the steam coil, the heat from the steam coil is used to exchange heat with the material in the raw material alcohol head heater, thus raising the material temperature. The steam after heat exchange becomes condensate and is discharged from the outlet at the other end of the steam coil. The ethoxylation reaction system of this invention operates under two conditions: normal production and initial start-up. The heat exchange mode of the heat exchange device of the ethoxylation reaction system includes a segmented heating mode and a full-process steam heating mode. During the initial start-up, the full-process steam heating mode is adopted: because the ethoxylation reaction has not yet started during the initial start-up, there is no heat of reaction to recover. At this time, the medium switching control valve group keeps the steam pipeline valve open and the pressurized water pipeline valve closed. Steam is introduced into the tube side of the double-pass coiled tube heat exchanger, directly heating the raw material alcohol head in the shell side, sequentially completing the preheating, dehydration, and temperature rise to the reaction initiation temperature, meeting the production needs in the initial stage of start-up. Under normal production conditions, a segmented heating mode is adopted: the heat of reaction generated by the ethoxylation reaction is absorbed by the closed-loop pressurized water system, raising the temperature of the pressurized water. The raw material alcohol head enters the raw material alcohol head heater. At this time, the medium switching control valve group automatically opens the pressurized water pipeline valve and closes the steam pipeline valve. The pressurized water flows within the tubes, exchanging heat with the raw material inside the raw material alcohol head heater, raising the temperature of the raw material and maintaining it for a certain period to meet the requirements of the vacuum dehydration process. The heat of reaction is fully utilized in this stage, eliminating the need for steam consumption. After the raw material moisture content is tested and found to be within acceptable limits, the medium switching control valve group automatically closes the pressurized water pipeline valve and opens the steam pipeline valve based on the temperature parameters. Steam is introduced into the raw material alcohol head heater to exchange heat with the raw material, raising its temperature again to the reaction initiation temperature. The raw material then leaves the raw material alcohol head heater and is transported to the reactor to participate in the reaction. The pressurized water, having absorbed heat from the raw material, cools down and again absorbs the heat of reaction through the first heat exchanger, completing the closed-loop cycle. Excess heat is transferred to the hot water system through the second heat exchanger, and the produced hot water is supplied to various users.The beneficial effects of the device of this invention are: excellent media isolation effect: the dual-pipe structure adopts physical isolation, which can completely avoid the mixing of pressurized water with media such as steam and cooling water, eliminating the risk of media contamination. Highly efficient utilization of waste heat in stages: it realizes the segmented utilization of reaction heat at different stages of raw material pretreatment, significantly reducing steam consumption and achieving remarkable energy saving and consumption reduction effects. Attached Figure Description

[0020] The following is a brief explanation of the contents depicted in the accompanying drawings and the markings therein: Figure 1 This is a schematic diagram of the heat exchange device of the ethoxylation reaction system according to the present invention; The labels in the attached diagram are as follows: 1. Raw material alcohol head heater; 2. Pressurized water coil; 3. Steam coil; 4. First pipeline; 5. First heat exchanger; 6. Reaction heat transfer pipeline; 7. Second pipeline; 8. Raw material inlet; 9. Raw material outlet; 10. Second heat exchanger; 11. Third pipeline; 12. Hot water user; 13. Hot water storage tank; 14. Fourth pipeline; 15. Steam supply pipeline; 16. Condensate discharge pipeline; 17. Steam input solenoid valve; 18. Steam output solenoid valve; 19. Pressurized water input solenoid valve; 20. Pressurized water output solenoid valve; 21. Reaction heat input pipeline; 22. Reaction heat output pipeline; 23. Pressurized water pump; 24. Pressurized water expansion tank; 25. Hot water circulation pump; 26. Fifth pipeline; 27. Fifth pipeline solenoid valve. Detailed Implementation

[0021] The following description, with reference to the accompanying drawings, provides a more detailed explanation of the specific embodiments of the present invention, including the shape and structure of each component, the relative positions and connections between the parts, the functions and working principles of each part: As attached Figure 1As shown, this invention relates to a heat exchange device for an ethoxylation reaction system. The raw material alcohol head heater 1 is internally equipped with a pressurized water coil 2 and a steam coil 3. The inlet of the pressurized water coil 2 is connected to a first pipeline 4, which in turn connects to a first heat exchanger 5. The first heat exchanger 5 is simultaneously connected to a reaction heat transport pipeline 6 of the ethoxylation reaction system. The first heat exchanger 5 is connected to the outlet of the pressurized water coil 2 via a second pipeline 7. The raw material alcohol head heater 1 is equipped with a raw material inlet 8 and a raw material outlet 9. The heat exchange mode of the ethoxylation reaction system heat exchange device includes a segmented heating mode and a full-process steam heating mode. To address the shortcomings of the prior art, an improved technical solution is proposed. In this structural configuration, the pressurized water coil 2 and the steam coil 3 are internally equipped with separate pipelines, isolated from each other, but both pass through the raw material alcohol head heater 1. The inlet of the pressurized water coil 2 is connected to the first pipeline 4, which in turn connects to the first heat exchanger 5. The first heat exchanger 5 is also connected to the reaction heat transfer pipeline 6 of the ethoxylation reaction system. Heat exchange is achieved between the first heat exchanger 5 and the reaction heat transfer pipeline 6, allowing pressurized hot water to be transported through the first pipeline to the pressurized water coil 2. The heat from the pressurized water coil 2 is used to heat the material in the raw material alcohol head heater 1, thus raising the material temperature. The outlet of the pressurized water coil 2 is connected to the first heat exchanger 5 through the second pipeline 7. The pressurized water that has undergone heat exchange in the raw material alcohol head heater 1 flows out from the second pipeline 7 and re-enters the first heat exchanger 5 to absorb heat, thus supplying pressurized hot water again and achieving a circulating heat exchange. The steam coil 3 passes through the raw material alcohol head heater 1. The inlet of the steam coil 3 is connected to the steam supply pipeline 15, which supplies high-temperature steam. When the high-temperature steam passes through the steam coil 3, the heat from the steam coil 3 is used to exchange heat with the material in the raw material alcohol head heater 1, thereby raising the material temperature. The steam after heat exchange becomes condensate and is discharged from the outlet at the other end of the steam coil 3. The ethoxylation reaction system of this invention operates under two conditions: normal production and initial start-up. The heat exchange mode of the heat exchange device of the ethoxylation reaction system includes a segmented heating mode and a full-process steam heating mode. During the initial start-up, the full-process steam heating mode is adopted: because the ethoxylation reaction has not yet started during the initial start-up, there is no heat of reaction to be recovered. At this time, the medium switching control valve group keeps the steam pipeline valve open and the pressurized water pipeline valve closed. Steam is introduced into the tube side of the double-pass coiled tube heat exchanger to directly heat the raw material alcohol head in the shell side, sequentially completing the preheating, dehydration, and temperature rise to the reaction initiation temperature, meeting the production needs in the initial stage of start-up. Under normal production conditions, a segmented heating mode is adopted: the heat of reaction generated by the ethoxylation reaction is absorbed by the closed pressurized water system, and the pressurized water temperature rises to 105-121℃. The raw material alcohol head enters the raw material alcohol head heater 1. At this time, the medium switching control valve group automatically opens the pressurized water pipeline valve and closes the steam pipeline valve.Pressurized water flows within the tubes, exchanging heat with the raw material inside the raw material alcohol head heater 1, raising the raw material temperature to 90-110℃ and maintaining it for 2-3 hours to meet the requirements of the vacuum dehydration process. The reaction heat is fully utilized in this stage, eliminating the need for steam consumption. After the raw material moisture content is deemed acceptable, the media switching control valve group automatically closes the pressurized water pipeline valve and opens the steam pipeline valve based on temperature parameters. Steam is introduced into the raw material alcohol head heater 1 to exchange heat with the raw material, raising its temperature to the reaction initiation temperature of 150℃. The raw material then leaves the raw material alcohol head heater 1 and is transported to the reactor to participate in the reaction. The pressurized water, having absorbed heat from the raw material, cools down and again absorbs reaction heat through the first heat exchanger, completing a closed-loop cycle. Excess heat is transferred to the hot water system through the second heat exchanger, and the produced hot water is supplied to various users. The beneficial effects of this invention's device are: excellent media isolation: the dual-pipe structure employs physical isolation, completely preventing the mixing of pressurized water with steam, cooling water, and other media, eliminating the risk of media contamination. Waste heat is utilized in stages: the reaction heat is utilized in stages at different stages of raw material pretreatment, which greatly reduces steam consumption and has a significant energy-saving and consumption-reducing effect. This invention features strong adaptability with dual operating modes: segmented heating and full-process steam heating modes can be flexibly switched, meeting both the waste heat recovery needs of normal production and adapting to the special operating conditions of initial start-up. It also boasts a high degree of automation: equipped with a pneumatic medium switching control valve group, it can automatically switch media according to process stage and temperature parameters, reducing manual operation intensity and improving temperature control accuracy.

[0022] A second heat exchanger 10 is installed on the second pipeline 7. The second heat exchanger 10 is also connected to a third pipeline 11. One end of the third pipeline 11 is connected to the inlet of the hot water user 12, and the other end is connected to the outlet of the hot water storage tank 13. One end of the fourth pipeline 14 is connected to the outlet of the hot water user 12, and the other end is connected to the inlet of the hot water storage tank 13. In this structure, the heat from the reaction heat transfer pipeline 6 is mainly used to supply the pressurized water to the coil 2. The excess heat is absorbed by the second heat exchanger and then transferred to the hot water user, thus realizing the utilization of thermal energy and avoiding waste.

[0023] The first pipe 4 and the second pipe 7 are connected to a fifth pipe 26. One end of the fifth pipe 26 connects to the first pipe 4 between the first heat exchanger 5 and the pressurized water coil 2, and the other end connects to the fourth pipe 7 between the second heat exchanger 10 and the raw material alcohol head heater 1. In this structure, the high-temperature water obtained by the first heat exchanger is supplied to the second heat exchanger 10 through the fifth pipe 26 when the pressurized water coil 2 is not being supplied. The second heat exchanger absorbs the water and then exchanges heat to supply hot water to users, thus utilizing thermal energy and avoiding waste. The pressurized water-wound pipe 2, located inside the raw material alcohol head heater 1, has a spiral tube structure, as does the steam-wound pipe 3, also located inside the raw material alcohol head heater 1. This spiral tube structure increases the heat exchange area of ​​the raw material alcohol head heater 1, thereby improving heat exchange efficiency.

[0024] The outlet of the steam coil 3 is connected to the condensate discharge pipe 16. A steam input solenoid valve 17 is installed near the inlet of the steam coil 3 on the steam supply pipe 15, and a steam output solenoid valve 18 is installed near the outlet of the steam coil 3 on the condensate discharge pipe 16. In this structure, the steam input solenoid valve 17 is used to control the on / off state and flow rate of the steam supply pipe 15. The steam output solenoid valve 18 is used to control the on / off state and flow rate of the outlet of the steam coil 3, enabling automatic control and improving the reliability and automation of the device control.

[0025] A pressurized water input solenoid valve 19 is installed on the first pipeline 4 near the inlet of the pressurized water coil 2, and a pressurized water output solenoid valve 20 is installed on the second pipeline 7 near the outlet of the pressurized water coil 2. In this configuration, the pressurized water input solenoid valve 19 controls the on / off state and flow rate of the pressurized hot water supplied to the pressurized water coil 2. The pressurized water output solenoid valve 20 controls the on / off state and flow rate of the outlet of the pressurized water coil 2.

[0026] The aforementioned reaction heat transmission pipeline 6 includes a reaction heat input pipeline 21 and a reaction heat output pipeline 22. In this structure, the reaction heat input pipeline 21 and the reaction heat output pipeline 22 are configured such that the heat from the reaction heat supply equipment is sent to the first heat exchanger via the reaction heat input pipeline 21 for heat exchange, and then discharged via the reaction heat output pipeline 22 after heat exchange is completed.

[0027] A pressurized water pump 23 is installed on the first pipeline 4 between the second heat exchanger 10 and the first heat exchanger 5. The first pipeline 4 is connected to a pressurized water expansion tank 24, which in turn is connected to the first pipeline 4 between the first heat exchanger 5 and the second heat exchanger 10. In this configuration, when pressurized high-temperature water is not required in the raw material alcohol head heater 1, the solenoid valve on the fifth pipeline 26 opens, allowing the pressurized superheated water from the first heat exchanger 5 to enter the second heat exchanger via the fifth pipeline 26 for heat exchange, ensuring reliable utilization of the heat exchanged in the first heat exchanger and avoiding waste of heat resources. When pressurized high-temperature water is required in the raw material alcohol head heater 1, the solenoid valve on the fifth pipeline 26 closes or is reduced in size, thereby supplying pressurized high-temperature water to the raw material alcohol head heater 1.

[0028] When the ethoxylation reaction system is started for the first time, it switches to full-process steam heating mode: no reaction heat is generated in the ethoxylation reaction system, no reaction heat is generated in the reaction heat delivery pipeline 6, the pressurized water input solenoid valve 19 and pressurized water output solenoid valve 20 of the pressurized water coil 2 are closed, the steam input solenoid valve 17 and steam output solenoid valve 18 are opened, and steam enters the steam coil 3 and the raw material alcohol head heater 1 for raw material heat exchange, thereby completing the entire process of preheating, dehydration and heating to the reaction initiation temperature of the raw material.

[0029] When the ethoxylation reaction system starts up and the reaction heat transmission pipeline 6 generates reaction heat, it enters normal production conditions and switches to segmented heating mode: the reaction heat generated by the ethoxylation reaction system is sent to the first heat exchanger 5 and the first pipeline 4 for heat exchange through the reaction heat transmission pipeline 6. The temperature of the pressurized water in the first pipeline 4 rises, the pressurized water input solenoid valve 19 and the pressurized water output solenoid valve 20 of the pressurized water loop 2 open, and the steam input solenoid valve 17 and the steam output solenoid valve 18 close. The pressurized water circulates and exchanges heat with the raw material inside the raw material alcohol head heater 1, raising the raw material to the first stage temperature. Then, the pressurized water input solenoid valve 19 and the pressurized water output solenoid valve 20 of the pressurized water loop 2 close, and the steam input solenoid valve 17 and the steam output solenoid valve 18 open. The steam exchanges heat with the raw material inside the raw material alcohol head heater 1, raising the raw material to the second stage temperature, i.e., the reaction initiation temperature. After that, the raw material is transported to the ethoxylation reaction system to participate in the reaction.

[0030] When the ethoxylation reaction system is started, the reaction heat transmission pipeline 6 generates reaction heat and enters normal production conditions. When the raw material alcohol head heater 1 has no heat exchange requirement, the fifth pipeline solenoid valve 27 is opened, the pressurized water input solenoid valve 19 and pressurized water output solenoid valve 20 of the pressurized water winding pipe 2 are closed, and the steam input solenoid valve 17 and steam output solenoid valve 18 are closed. The pressurized water in the first pipeline 4 flows back to the second pipeline 7 through the fifth pipeline 26. The pressurized water in the second pipeline 7 simultaneously exchanges heat with the water in the second heat exchanger 10 and the third pipeline 11, heating the water in the third pipeline 11. The heated water in the third pipeline 11 is supplied to the hot water user 12 and returns to the hot water storage tank through the fourth pipeline 14.

[0031] This invention also relates to a heat exchange method for an ethoxylation reaction system that enables dual-pipeline, dual-medium isolated transport and switching control, effectively meeting the heating mode switching requirements of the initial start-up and normal production processes of the ethoxylation reaction system, achieving efficient utilization of waste heat in a cascade manner, and meeting the requirements of energy conservation, emission reduction, and green low-carbon development. The steps of the heat exchange method are as follows: S1. When the ethoxylation reaction system is started for the first time, the ethoxylation reaction system switches to full steam heating mode: no reaction heat is generated in the ethoxylation reaction system, no reaction heat is generated in the reaction heat delivery pipeline 6, the pressurized water input solenoid valve 19 and pressurized water output solenoid valve 20 of the pressurized water coil 2 are closed, the steam input solenoid valve 17 and steam output solenoid valve 18 are opened, and the steam enters the steam coil 3 and the raw material alcohol head heater 1 for raw material heat exchange, and completes the entire process of raw material preheating, dehydration and heating to the reaction initiation temperature in sequence; S2. When the reaction heat transmission pipeline 6 generates reaction heat after the ethoxylation reaction system starts up, it enters normal production conditions and the ethoxylation reaction system switches to segmented heating mode: the reaction heat generated by the ethoxylation reaction system is sent to the first heat exchanger 5 and the first pipeline 4 through the reaction heat transmission pipeline 6 for heat exchange. The temperature of the pressurized water in the first pipeline 4 rises, the pressurized water input solenoid valve 19 and the pressurized water output solenoid valve 20 of the pressurized water loop 2 are opened, the steam input solenoid valve 17 and the steam output solenoid valve 18 are closed, the pressurized water circulates, and the pressurized water exchanges heat with the raw material inside the raw material alcohol head heater 1, raising the raw material to the first stage temperature; S3. The pressurized water inlet solenoid valve 19 and pressurized water outlet solenoid valve 20 of the pressurized water coil 2 are closed, while the steam inlet solenoid valve 17 and steam outlet solenoid valve 18 are opened. The steam exchanges heat with the raw material inside the raw material alcohol head heater 1, raising the raw material to the second stage temperature, i.e. the reaction initiation temperature. After that, the raw material is transported to the ethoxylation reaction system to participate in the reaction.

[0032] S4. When the steam input solenoid valve 17 and the steam output solenoid valve 18 are open, the pressurized water input solenoid valve 19 and the pressurized water output solenoid valve 20 of the pressurized water loop 2 are closed, and the pressurized water in the second pipeline 7 flows back to the second pipeline 7 through the fifth pipeline 26; the pressurized water in the second pipeline 7 simultaneously exchanges heat with the water in the second heat exchanger 10 and the third pipeline 11, heating the water in the third pipeline 11, and the heated water in the third pipeline 11 is supplied to the hot water user 12.

[0033] The device of this invention develops a technical solution that enables cascaded utilization of reaction heat, effective isolation between two media, and adaptability to the stringent requirements of surfactant ethoxylation raw material pretreatment and media switching conditions. It reduces steam consumption in the raw material pretreatment process, improves the utilization rate of reaction heat, and solves the problems of raw material contamination and operating condition fluctuations caused by media leakage, addressing urgent technical issues in the field. The system of this invention has two operating modes: a segmented heating mode, where pressurized water is introduced during raw material preheating and vacuum dehydration, and steam heating is switched when the raw material needs to be heated to the reaction initiation temperature; and a full-process steam heating mode, which can meet the requirements of initial start-up without reaction heat. This system is suitable for waste heat recovery from the highly exothermic reaction in ethoxylation units and for heating operations in surfactant raw material pretreatment processes.

[0034] When the system of this invention is in operation, the raw materials need to undergo two core pretreatment processes in sequence: heating and vacuum dehydration. After passing the moisture test, the materials need to be heated again to the reaction initiation temperature before being sent to the ethoxylation reaction system to participate in the polymerization reaction. The temperature range of the vacuum dehydration process is strictly controlled between 90-105℃, and this temperature needs to be maintained for 2-3 hours, and for some low-boiling-point raw materials, it may even need to be maintained for more than 5-6 hours to ensure that the moisture in the raw materials is fully removed. The reaction initiation temperature is about 150℃, and the polymerization reaction temperature is stable at 160-180℃ in daily production.

[0035] The present invention has been described above by way of example with reference to the accompanying drawings. Obviously, the specific implementation of the present invention is not limited to the above-described manner. Any improvements made by adopting the inventive concept and technical solution of the present invention, or the direct application of the inventive concept and technical solution of the present invention to other occasions without modification, are all within the protection scope of the present invention.

Claims

1. A heat exchange device for an ethoxylation reaction system, characterized in that: The raw material alcohol head heater (1) is equipped with a pressurized water coil (2) and a steam coil (3). The inlet of the pressurized water coil (2) is connected to the first pipeline (4). The first pipeline (4) is connected to the first heat exchanger (5). The first heat exchanger (5) is simultaneously connected to the reaction heat transport pipeline (6) of the ethoxylation reaction system. The first heat exchanger (5) is connected to the outlet of the pressurized water coil (2) through the second pipeline (7). The heat exchange mode of the heat exchange device of the ethoxylation reaction system includes segmented heating mode and full steam heating mode.

2. The heat exchange device for the ethoxylation reaction system according to claim 1, characterized in that: A second heat exchanger (10) is installed on the second pipeline (7). The second heat exchanger (10) is also connected to the third pipeline (11). One end of the third pipeline (11) is connected to the inlet of the hot water user (12), and the other end of the third pipeline (11) is connected to the outlet of the hot water storage tank (13). One end of the fourth pipeline (14) is connected to the outlet of the hot water user (12), and the other end of the fourth pipeline (14) is connected to the inlet of the hot water storage tank (13).

3. The heat exchange device for the ethoxylation reaction system according to claim 1 or 2, characterized in that: The first pipeline (4) and the second pipeline (7) are connected to the fifth pipeline (26). One end of the fifth pipeline (26) is connected to the first pipeline (4) between the first heat exchanger (5) and the pressurized water coil (2), and the other end of the fifth pipeline (26) is connected to the fourth pipeline (7) between the second heat exchanger (10) and the raw material alcohol head heater (1).

4. The heat exchange device for the ethoxylation reaction system according to claim 1 or 2, characterized in that: The pressurized water coil (2) is located inside the raw material alcohol head heater (1) and has a spiral tube structure. The steam coil (3) is located inside the raw material alcohol head heater (1) and has a spiral tube structure. The raw material alcohol head heater (1) is provided with a raw material inlet (8) and a raw material outlet (9).

5. The heat exchange device for the ethoxylation reaction system according to claim 1 or 2, characterized in that: The steam coil (3) is connected to the steam supply pipeline (15) at the inlet and to the condensate discharge pipeline (16) at the outlet. A steam input solenoid valve (17) is installed near the inlet of the steam coil (3) in the steam supply pipeline (15) and a steam output solenoid valve (18) is installed near the outlet of the steam coil (3) in the condensate discharge pipeline (16).

6. The heat exchange device for the ethoxylation reaction system according to claim 1 or 2, characterized in that: A pressurized water input solenoid valve (19) is installed on the first pipeline (4) near the inlet of the pressurized water loop (2), and a pressurized water output solenoid valve (20) is installed on the second pipeline (7) near the outlet of the pressurized water loop (2); a pressurized water pump (23) is installed on the first pipeline (4) between the second heat exchanger (10) and the first heat exchanger (5); the first pipeline (4) is connected to the pressurized water expansion tank (24), and the first pipeline (4) is connected between the first heat exchanger (5) and the second heat exchanger (10).

7. The heat exchange device for the ethoxylation reaction system according to claim 6, characterized in that: When the ethoxylation reaction system is started for the first time, the raw material alcohol head heater (1) switches to full steam heating mode: no reaction heat is generated in the ethoxylation reaction system, no reaction heat is generated in the reaction heat transmission pipeline (6), the pressurized water input solenoid valve (19) and pressurized water output solenoid valve (20) of the pressurized water coil (2) are closed, the steam input solenoid valve (17) and steam output solenoid valve (18) are opened, and steam enters the steam coil (3) and the raw material alcohol head heater (1) for raw material heat exchange, thereby completing the preheating, dehydration and heating to the reaction initiation temperature of the raw material in sequence.

8. The heat exchange device for the ethoxylation reaction system according to claim 6, characterized in that: When the ethoxylation reaction system starts up and the reaction heat transmission pipeline (6) generates reaction heat, it enters normal production conditions and carries out the preparation process for the next batch of raw materials. At this time, the raw material alcohol head heater (1) is switched to segmented heating mode: the reaction heat generated by the ethoxylation reaction system is sent to the first heat exchanger (5) and the first pipeline (4) for heat exchange through the reaction heat transmission pipeline (6). The temperature of the pressurized water in the first pipeline (4) rises, and the pressurized water input solenoid valve (19) and pressurized water output solenoid valve (20) of the pressurized water loop pipe (2) are opened. At this time, the fifth pipeline solenoid valve (27) is closed, the steam input solenoid valve (17) and the steam output solenoid valve (18) are closed, and the pressurized water passes through the second pipeline. The pipeline (7) and the second heat exchanger (10) return to the first pipeline (4) to complete the closed-loop circulation. The pressurized water exchanges heat with the raw material inside the raw material alcohol head heater (1) to raise the raw material to the first stage temperature, i.e. the raw material dehydration temperature. Then, the first stage temperature is controlled and maintained by the temperature regulating valve (19) to complete the raw material dehydration process. Then, the pressurized water input solenoid valve (19) and pressurized water output solenoid valve (20) of the pressurized water loop (2) are closed, and the steam input solenoid valve (17) and steam output solenoid valve (18) are opened. The steam exchanges heat with the raw material inside the raw material alcohol head heater (1) to raise the raw material to the second stage temperature, i.e. the reaction initiation temperature. Then, the raw material is transported to the ethoxylation reaction system to participate in the reaction.

9. The heat exchange device for the ethoxylation reaction system according to claim 8, characterized in that: When the ethoxylation reaction system is started, the reaction heat transmission pipeline (6) generates reaction heat and enters normal production conditions. When the raw material alcohol head heater (1) has no heat exchange requirement, the fifth pipeline solenoid valve (27) is opened, the pressurized water input solenoid valve (19) and pressurized water output solenoid valve (20) of the pressurized water winding pipe (2) are closed, the steam input solenoid valve (17) and steam output solenoid valve (18) are closed, and the pressurized water in the first pipeline (4) flows back to the second pipeline (7) through the fifth pipeline (26). The pressurized water in the second pipeline (7) simultaneously exchanges heat with the water in the second heat exchanger (10) and the third pipeline (11) to heat the water in the third pipeline (11). The water heated by the third pipeline (11) is supplied to the hot water user (12) and returns to the hot water storage tank through the fourth pipeline (14).

10. A heat exchange method for an ethoxylation reaction system, characterized in that: S1. When the ethoxylation reaction system is started for the first time, the ethoxylation reaction system switches to full steam heating mode: the ethoxylation reaction system does not generate reaction heat, the reaction heat transmission pipeline (6) does not generate reaction heat, the pressurized water input solenoid valve (19) and pressurized water output solenoid valve (20) of the pressurized water coil (2) are closed, the steam input solenoid valve (17) and steam output solenoid valve (18) are opened, the steam enters the steam coil (3) and the raw material alcohol head heater (1) for raw material heat exchange, and the preheating, dehydration and heating to the reaction initiation temperature of the raw material are completed in sequence. S2. When the reaction heat transmission pipeline (6) generates reaction heat after the ethoxylation reaction system is started, it enters normal production conditions and the ethoxylation reaction system switches to segmented heating mode: the reaction heat generated by the ethoxylation reaction system is sent to the first heat exchanger (5) and the first pipeline (4) through the reaction heat transmission pipeline (6) for heat exchange. The temperature of the pressurized water in the first pipeline (4) rises. The pressurized water input solenoid valve (19) and pressurized water output solenoid valve (20) of the pressurized water loop (2) are opened, and the steam input solenoid valve (17) and steam output solenoid valve (18) are closed. The pressurized water circulates and exchanges heat with the raw material inside the raw material alcohol head heater (1) to raise the temperature of the raw material to the first stage temperature. S3. The pressurized water input solenoid valve (19) and pressurized water output solenoid valve (20) of the pressurized water coil (2) are closed, and the steam input solenoid valve (17) and steam output solenoid valve (18) are opened. The steam exchanges heat with the raw material inside the raw material alcohol head heater (1) to raise the raw material to the second stage temperature, that is, the reaction initiation temperature. After that, the raw material is transported to the ethoxylation reaction system to participate in the reaction. S4. When the steam input solenoid valve (17) and the steam output solenoid valve (18) are open, the pressurized water input solenoid valve (19) and the pressurized water output solenoid valve (20) of the pressurized water loop (2) are closed, and the pressurized water in the second pipeline (7) flows back to the second pipeline (7) through the fifth pipeline (26); the pressurized water in the second pipeline (7) simultaneously exchanges heat with the water in the second heat exchanger (10) and the third pipeline (11), heating the water in the third pipeline (11), and the heated water in the third pipeline (11) is supplied to the hot water user (12).

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