An automatic temperature control method for a polyether monomer reactor

Abstract

The present invention discloses an automatic temperature control method for a polyether monomer reaction kettle, belonging to the technical field of chemical polyether reaction. It is characterized in that the pre-reaction temperature control system directly controls the temperature of the circulating material in the pre-reaction kettle and indirectly controls the reaction temperature of the pre-reaction kettle. After the pre-reaction kettle produces qualified intermediates, it enters the main reaction temperature control system. The main reaction temperature control system simultaneously controls the temperature of the double-circulating material in the main reaction kettle and indirectly controls the reaction temperature of the main reaction kettle, solving the technical problems that the existing device uses a heat transfer water system to control the temperature of the reaction kettle, and there are unstable temperature control and large temperature fluctuations in the pre-reaction kettle and the main reaction kettle during the production process. It is mainly applied to the temperature control of the polyether monomer production reaction kettle.

Description

Technical Field

[0001] The present invention relates to the technical field of chemical polyether reaction, and specifically relates to an automatic temperature control method for a polyether monomer reaction kettle. Background Art

[0002] After nearly a century of development, the production process of polyether monomers has become a relatively mature process technology. This process refers to using ethylene oxide as a raw material to undergo an addition polymerization reaction with various initiators (such as ethylene glycol and fatty alcohols containing active hydrogen in the molecule) under the action of a catalyst to produce polyether macromonomer products of various specifications. The characteristics of such production processes mainly include: it is a strongly exothermic reaction (the reaction heat is about 2140 kJ / kg EO); the reaction is an intermittent reaction, the product has a high viscosity and is easy to block; the reaction raw materials contain ethylene oxide (EO) gas (flammable, explosive and highly toxic), and once leaked, it is extremely easy to cause fires and explosions, resulting in major safety accidents.

[0003] The polymerization reaction mechanism is complex and has characteristics such as large lag, large inertia, and nonlinearity. Reaction temperature control is an important factor affecting product quality. When adding ethylene oxide dropwise in the pre-reaction and main reaction of isopentenol polyoxyethylene ether and methallyl alcohol polyoxyethylene ether in the device, due to the influence of equipment and actual operation conditions on site, the conventional process package reaction kettle temperature control scheme adopts the method of cascading the reaction kettle temperature with the outlet temperature of the circulating heat exchanger and then separately controlling the cold and hot water valves. When using heat transfer oil as the heat removal medium, this method has a good control effect. However, in the production system using heat transfer water for heat removal, affected by factors such as the form of cold and hot water regulating valves, the matching degree of on-site pipelines, the efficiency of the circulating heat exchanger, and the circulating amount of the reaction kettle materials, the reaction kettle temperature cannot be effectively controlled.

[0004] During the reaction process, the temperature of the reaction kettle is mainly controlled by the heat transfer water system, and the heat transfer water temperature is controlled by adjusting the ratio of cold water to hot water. The traditional temperature control scheme is a cascade control, with the circulating temperature of the reaction kettle materials as the main loop and the temperature after mixing cold and hot water as the secondary loop. The actuators of the secondary loop are the cold water valve and hot water valve of the heat transfer water system respectively. The cold and hot water valves adopt cross split-range control. Restricted by the characteristics of the polymerization reaction itself, such as nonlinearity, large inertia, and large temperature lag, which are difficult to control, and factors such as the form of cold and hot water regulating valves, the matching degree of on-site pipelines, the efficiency of the circulating heat exchanger, and the circulating amount of the reaction kettle materials, the control error reaches ±6°C, and overheating often occurs, which does not meet the production requirements of the device. At the same time, there are many interference factors in this temperature control system, and overheating often occurs during the production process, and the reaction kettle temperature repeatability is not good. The operation difficulty for operators is large, the labor intensity is high, and the production cycle is uncontrollable.

[0005] Therefore, our company proposes an automatic temperature control method for a polyether monomer reaction kettle. Summary of the Invention

[0006] Objective of the Invention: The present invention aims to provide an automatic temperature control method for a polyether monomer reaction kettle to solve the technical problems that in the existing device using a heat transfer water system for reaction kettle temperature control, the pre-reaction kettle and the main reaction kettle have unstable temperature control and large temperature fluctuations during the production process.

[0007] The specific technical solution of the present invention is as follows:

[0008] An automatic temperature control method for a polyether monomer reaction kettle, including the action steps of a pre-reaction temperature control system and the action steps of a main reaction temperature control system, is characterized in that the pre-reaction temperature control system directly controls the temperature of the circulating material in the pre-reaction kettle and indirectly controls the reaction temperature of the pre-reaction kettle. After the pre-reaction kettle produces qualified intermediates, it enters the action of the main reaction temperature control system. The main reaction temperature control system simultaneously controls the temperature of the double-circulating material in the main reaction kettle and indirectly controls the reaction temperature of the main reaction kettle.

[0009] Further, the action steps of the pre-reaction temperature control system include the following steps:

[0010] Step 1: Feeding and heating up the pre-reaction kettle:

[0011] Open the chain initiator feeding valve to add the chain initiator to the pre-reaction kettle, which is metered by the chain initiator mass flowmeter. When the pre-reaction kettle material level gauge monitors that the liquid level in the pre-reaction kettle reaches 5 - 15%, open the inlet valve of the circulation pump to start the pre-reaction kettle material circulation pump. The chain initiator in the pre-reaction kettle starts to circulate through the pre-reaction kettle circulation heat exchanger. After the cumulative value of the chain initiator mass flowmeter reaches 1000 - 2000 kg, close the chain initiator feeding valve, open the hot water valve of the circulation heat exchanger to introduce hot water into the shell side of the pre-reaction kettle circulation heat exchanger, and heat up the chain initiator in the tube side of the pre-reaction kettle circulation heat exchanger. When the pre-reaction kettle material thermometer monitors that the temperature of the chain initiator in the pre-reaction kettle rises to 85 - 95 °C, open the ethylene oxide feeding valve and drip ethylene oxide into the pre-reaction kettle, and adjust the ethylene oxide feeding valve to control the flow rate of the ethylene oxide mass flowmeter in the pre-reaction kettle at 0 - 3000 kg / h.

[0012] Step 2: Starting the pre-reaction kettle temperature automatic control system:

[0013] While dripping ethylene oxide into the pre-reaction kettle, the pre-reaction kettle temperature control system is put into automatic operation. The set value of the temperature control system is automatically set within the range of 100 - 120 °C. Ethylene oxide continues to be automatically dripped relying on the ethylene oxide feeding valve and the ethylene oxide mass flowmeter in the pre-reaction kettle. The pre-reaction kettle temperature control system uses the monitored value of the thermometer at the outlet of the pre-reaction kettle circulation heat exchanger as the measured value of the temperature control system. The set value of the temperature control system is 100 - 120 °C. The output of the temperature control system controls the opening degrees of the hot water valve and the cold water valve of the circulation heat exchanger. The corresponding relationship is as follows in the table:

[0014]

[0015] The temperature control system controls the ratio of hot water and cold water, and then controls the water temperature entering the shell side of the pre-reactor circulation heat exchanger. Through the adjustment of the temperature control system, the outlet temperature of the circulation heat exchanger is finally controlled within the range of ±2°C of the set value of the temperature control system. After the outlet temperature of the material in the pre-reactor circulation heat exchanger is stabilized, the pre-reactor material thermometer of the reaction material in the pre-reactor is within the range of ±1.5°C of the target temperature.

[0016] Step 3: Pre-reactor over-temperature and advance control:

[0017] During the dropping of ethylene oxide in the pre-reactor, when the pre-reactor material thermometer monitors that the temperature exceeds 100 - 128°C, the opening of the ethylene oxide feed valve will automatically decrease, the measured value of the ethylene oxide mass flowmeter in the pre-reactor will decrease at a flow rate of 500 - 1000 kg / h, the reaction intensity of the material in the pre-reactor will weaken, and the pre-reactor material thermometer in the reaction kettle will stop rising. When the temperature control system detects a downward trend in the pre-reactor material thermometer, the ethylene oxide feed valve will return to its original opening. During the entire dropping process of pre-reaction ethylene oxide, the pre-reactor material thermometer remains within the range of ±1.5°C of the target temperature.

[0018] Step 4: Temperature control in the curing stage:

[0019] After the cumulative value of the pre-reaction ethylene oxide mass flowmeter reaches 5000 - 9000 kg, the ethylene oxide feed valve is closed, and the reaction enters the curing stage. The set value of the pre-reaction temperature control system is automatically increased by 2 - 8°C on the original basis, and other control parameters of the temperature control system remain unchanged. During this stage, the pre-reactor material thermometer of the material in the pre-reactor is controlled at 100 - 140°C, and the entire curing process lasts for 20 - 90 min. The intermediate after curing in the pre-reactor enters the main reactor for further reaction.

[0020] Furthermore, the main reaction temperature control system includes the following steps:

[0021] Step 1: Feeding and heating in the main reactor:

[0022] Open the intermediate feed valve of the main reactor to add intermediate to the main reactor, which is metered by the intermediate mass flowmeter. After the main reactor material level gauge monitors that the liquid level in the main reactor reaches 15 - 25%, open the inlet valve of the main reactor small circulation pump to start the small circulation pump, and the intermediate in the main reactor starts to circulate through the small circulation heat exchanger. This circulation is the small circulation of the main reactor;

[0023] After the small circulation is established, when the liquid level gauge of the main reactor material monitors that the liquid level reaches 20 - 30%, open the inlet valve of the main reactor large circulation pump to start the large circulation pump. The intermediate in the main reactor begins to circulate through the large circulation heat exchanger, and this circulation is the main reactor large circulation;

[0024] After the cumulative value of the intermediate mass flowmeter reaches 4000 - 8000 kg, close the intermediate feed valve of the main reactor, open the hot water valve of the small circulation heat exchanger and the hot water valve of the large circulation heat exchanger to introduce hot water into the shell sides of the small circulation heat exchanger and the large circulation heat exchanger respectively, and heat up the intermediate in the tube side of the circulation heat exchanger. After the main reactor material thermometer in the main reactor monitors that the intermediate temperature reaches 85 - 100 °C, open the ethylene oxide feed valve of the main reactor, and drip ethylene oxide into the main reactor. The ethylene oxide feed valve of the main reactor controls the flow rate of the ethylene oxide mass flowmeter at 0 - 12000 kg / h.

[0025] Step 2: Start the automatic temperature control system of the main reactor:

[0026] While the ethylene oxide is being dripped into the main reactor, the automatic temperature control systems of the main reaction small circulation and the main reaction large circulation are started. The monitored value of the large circulation heat exchanger outlet thermometer of the large circulation heat exchanger is used as the measured value of the large circulation temperature control system. The set value of the large circulation temperature control system is usually in the range of 115 - 125 °C. The monitored value of the small circulation heat exchanger outlet thermometer of the small circulation heat exchanger is used as the measured value of the small circulation temperature control system. The set value of the small circulation thermometer control system is usually in the range of 110 - 125 °C. The large circulation temperature control system outputs to control the hot water valve and the cold water valve of the large circulation heat exchanger, and the small circulation temperature control system outputs to control the hot water valve and the cold water valve of the small circulation heat exchanger. The corresponding relationship is as follows in the table:

[0027]

[0028]

[0029] The temperature control system controls the ratio of hot water and cold water, controls the water temperature entering the shell sides of the large circulation heat exchanger and the small circulation heat exchanger. Through the adjustment of the temperature control system, finally control the large circulation heat exchanger outlet thermometer and the small circulation heat exchanger outlet thermometer within the range of ±2 °C of the set value of the temperature control system. After the large circulation heat exchanger outlet temperature and the small circulation heat exchanger outlet temperature are stable, the main reactor material thermometer of the reaction material in the main reactor is constant within the range of ±1.5 °C of the target temperature.

[0030] Step 3: Temperature control in the ripening stage:

[0031] After the cumulative value of the mass flowmeter of ethylene oxide in the main reaction reaches 10,000 - 36,000 kg, close the ethylene oxide feed valve of the main reactor. The reaction enters the aging stage. The set value of the main reaction temperature control system is automatically increased by 2 - 8 °C on the original basis, and other control parameters of the temperature control system remain unchanged. During this stage, the temperature of the material in the main reactor is controlled at 120 - 160 °C by the thermometer of the main reactor material, and the entire aging process lasts for 20 - 90 min.

[0032] The present invention has the following beneficial effects:

[0033] We simplify the complex control, reduce the introduction of interference factors, no longer use the traditional cascade and split-range control of cold and hot water regulating valves, directly select the temperature of the material at the outlet of the heat exchanger as the control parameter, and realize the specific matching of the opening degrees of the cold and hot water valves through a new temperature control system. The entire temperature control process is fully automatic and does not require manual intervention. At the same time, we have also realized the following functions: when the temperature of the reactor exceeds the set value, the dropping amount of ethylene oxide is automatically reduced to ensure that the temperature of the reactor does not exceed the limit; after it is monitored that the temperature of the reactor has a downward trend, the dropping amount of ethylene oxide automatically returns to the original set value; during the aging stage of the reaction, the set value of the temperature controller is automatically increased to ensure the aging effect; the entire production process is fully intelligentized;

[0034] The temperature control of the reactor in the original design scheme is a cascade control, with the circulating temperature of the reactor material as the main loop and the temperature after mixing cold and hot water as the secondary loop. The actuators of the secondary loop are the cold water valve and the hot water valve of the heat conduction water system respectively. The cold and hot water valves adopt split-range control. Affected by factors such as the characteristics of the polymerization reaction, the form of the cold and hot water regulating valves, the matching degree of the on-site pipelines, the efficiency of the circulating heat exchanger, and the circulating amount of the reactor material, the temperature often exceeds the limit during the production process, and the temperature of the reactor has poor repeatability. The operation difficulty for operators is large, the labor intensity is high, and the production cycle is uncontrollable;

[0035] Compared with the prior art, this scheme replaces the temperature control of the reactor in the original design scheme. After using the temperature control system of this method, the operation is simple, the temperature control is stable, the repeatability is good, and the reaction cycle is shortened, which is of great significance for improving product quality, reducing production costs, and avoiding waste of resources. Brief Description of the Drawings

[0036] Figure 1 It is a schematic diagram of the pre-reactor in the present invention;

[0037] Figure 2 It is a schematic diagram of the main reactor in the present invention.

[0038] In the figure: 1. Chain initiator feed valve; 2. Chain initiator mass flowmeter; 3. Ethylene oxide feed valve; 4. Ethylene oxide mass flowmeter for the pre-reactor; 5. Hot water valve for the circulation heat exchanger; 6. Cold water valve for the circulation heat exchanger; 7. Circulation heat exchanger for the pre-reactor; 8. Outlet temperature of the circulation heat exchanger; 9. Material thermometer for the pre-reactor; 10. Material level gauge for the pre-reactor; 11. Pre-reactor; 12. Inlet valve for the circulation pump; 13. Material circulation pump for the pre-reactor; 14. Intermediate feed valve for the main reactor; 15. Intermediate mass flowmeter; 16. Ethylene oxide feed valve for the main reactor; 17. Ethylene oxide mass flowmeter; 18. Hot water valve for the large circulation heat exchanger; 19. Cold water valve for the large circulation heat exchanger; 20. Large circulation heat exchanger; 21. Outlet thermometer for the large circulation heat exchanger; 22. Hot water valve for the small circulation heat exchanger; 23. Cold water valve for the small circulation heat exchanger; 24. Small circulation heat exchanger; 25. Outlet thermometer for the small circulation heat exchanger; 26. Material thermometer for the main reactor; 27. Material level gauge for the main reactor; 28. Large circulation pump; 29. Small circulation pump; 30. Main reactor; 31. Inlet valve for the large circulation pump of the main reactor; 32. Inlet valve for the small circulation pump of the main reactor. Detailed implementation mode

[0039] The present invention is a brand-new automatic control method for the temperature of a polyether monomer reactor, and the key points are as follows:

[0040] Directly select the temperature of the outlet material of the heat exchanger as the control parameter, and adopt a new temperature control system to achieve a specific combination of the opening degrees of the cold and hot water valves, achieving: when the temperature of the reactor exceeds the set value, the dropping amount of ethylene oxide automatically decreases; after monitoring that the temperature of the reactor has a downward trend, the dropping amount of ethylene oxide automatically returns to the original set value; in the aging stage of the reaction, the set value of the temperature controller automatically increases; after adopting the brand-new temperature control system, the temperature control of the reactor is stable and has good repeatability.

[0041] The present invention will be described in detail below through specific embodiments, but the present invention cannot be limited to the scope of the described embodiments.

[0042] Original control method:

[0043] In the original control scheme, the normal dropping flow rate of pre-reaction ethylene oxide is 1800 kg / h. After using the new reaction kettle temperature control method, the dropping flow rate of ethylene oxide can be increased to 2400 kg / h, which can shorten the reaction time and improve production efficiency. The traditional temperature control scheme is a cascade control, with the temperature of the material at the outlet of the pre-reaction kettle circulation heat exchanger as the main loop and the temperature after mixing cold and hot water as the secondary loop. The actuators of the secondary loop are the cold water valve and the hot water valve of the heat conduction water system respectively. The cold and hot water valves adopt cross split-range control, which is affected by factors such as the characteristics of the polymerization reaction, the form of the cold and hot water regulating valves, the matching degree of the on-site pipelines, the efficiency of the circulation heat exchanger, and the material circulation volume of the reaction kettle. There are many interference factors in this temperature control system, and the heat exchange system is complex, which affects the control effect in many aspects. The temperature control error of the reaction kettle reaches ±6°C, and over-temperature often occurs, which does not meet the production requirements of the device.

[0044] Table of the corresponding relationship between the valve positions of the pre-reaction cold and hot water valves in the original control scheme:

[0045]

[0046] In the original control scheme, the normal dropping flow rate of main-reaction ethylene oxide is 8500 kg / h. After using the new reaction kettle temperature control method, the dropping flow rate of ethylene oxide can be increased to 10500 kg / h, which can shorten the reaction time and improve production efficiency. The main reaction kettle has two material circulation heat removal systems. The traditional temperature control scheme is a cascade control, with the temperature of the material at the outlet of the main reaction kettle circulation heat exchanger as the main loop and the temperature after mixing cold and hot water as the secondary loop. The actuators of the secondary loop are the cold water valve and the hot water valve of the heat conduction water system respectively. The cold and hot water valves adopt cross split-range control, which is affected by factors such as the characteristics of the polymerization reaction, the form of the cold and hot water regulating valves, the matching degree of the on-site pipelines, the efficiency of the circulation heat exchanger, and the material circulation volume of the reaction kettle. There are many interference factors in this temperature control system, and the heat exchange system is complex, which affects the control effect in many aspects. The temperature control error of the reaction kettle reaches ±6°C, and over-temperature often occurs, which does not meet the production requirements of the device.

[0047] Table of the corresponding relationship between the valve positions of the main-reaction cold and hot water valves in the original control scheme:

[0048]

[0049] Example 1

[0050] An automatic temperature control method for a polyether monomer reactor, including the action steps of a pre-reaction temperature control system and the action steps of a main-reaction temperature control system, is characterized in that the pre-reaction temperature control system directly controls the temperature of the circulating material in the pre-reactor 11 and indirectly controls the reaction temperature of the pre-reactor 11. After the pre-reactor 11 produces qualified intermediates, it enters the action of the main-reaction temperature control system. The main-reaction temperature control system simultaneously controls the temperature of the double-circulating material in the main-reactor 30 and indirectly controls the reaction temperature of the main-reactor 30.

[0051] The action steps of the pre-reaction temperature control system include the following steps:

[0052] Step 1: Feeding and heating up the pre-reactor:

[0053] Open the chain initiator feed valve 1 to add the chain initiator to the pre-reactor 11, which is metered by the chain initiator mass flowmeter 2. When the pre-reactor material level gauge 10 monitors that the liquid level in the pre-reactor 11 reaches 7%, open the circulation pump inlet valve 12 to start the pre-reactor material circulation pump 13. The chain initiator in the pre-reactor starts to circulate through the pre-reactor circulation heat exchanger 7. After the cumulative value of the chain initiator mass flowmeter 2 reaches 1185 kg, close the chain initiator feed valve 1, open the hot water valve 5 of the circulation heat exchanger to introduce hot water into the shell side of the pre-reactor circulation heat exchanger 7, and heat up the chain initiator in the tube side of the pre-reactor circulation heat exchanger 7. When the pre-reactor material thermometer 9 monitors that the temperature of the chain initiator in the pre-reactor 11 rises to 92 °C, open the ethylene oxide feed valve 3 and drip ethylene oxide into the pre-reactor 11, and adjust the ethylene oxide feed valve 3 to control the flow rate of the pre-reactor ethylene oxide mass flowmeter 4 at 2300 kg / h.

[0054] Step 2: Start the pre-reaction temperature automatic control system:

[0055] While dripping ethylene oxide into the pre-reactor 11, the pre-reaction temperature control system is put into automatic operation, and the set value of the temperature control system is automatically set to 112 °C. Ethylene oxide continues to be automatically dripped relying on the ethylene oxide feed valve 3 and the pre-reactor ethylene oxide mass flowmeter 4. The pre-reaction temperature control system uses the monitored value of the outlet thermometer 8 of the pre-reactor circulation heat exchanger 7 as the measured value of the temperature control system. The output of the temperature control system controls the opening degrees of the hot water valve 5 and the cold water valve 6 of the circulation heat exchanger. The corresponding relationship is as follows in the table:

[0056]

[0057] The temperature control system controls the ratio of hot water and cold water, and thus controls the water temperature entering the shell side of the pre-reactor circulation heat exchanger 7. Through the adjustment of the temperature control system, the outlet temperature 8 of the circulation heat exchanger is finally controlled within the range of 112 ± 2°C. After the outlet temperature 8 of the material of the pre-reactor circulation heat exchanger 7 stabilizes, the pre-reactor material thermometer 9 of the reaction material in the pre-reactor 11 is within the range of 126 ± 1.5°C.

[0058] Step 3: Pre-reactor over-temperature prevention and advanced control:

[0059] During the dropping of ethylene oxide in the pre-reactor 11, when the pre-reactor material thermometer 9 monitors that the temperature exceeds 127°C, the ethylene oxide feed valve 3 will automatically reduce the opening degree, and the measured value of the pre-reactor ethylene oxide mass flowmeter 4 will decrease at a flow rate of 600 kg / h. The reaction intensity of the material in the pre-reactor 11 weakens, and the pre-reactor material thermometer 9 of the material in the reaction kettle stops rising. When the temperature control system detects a downward trend in the pre-reactor material thermometer 9, the ethylene oxide feed valve 3 returns to the original opening degree. During the entire dropping process of pre-reaction ethylene oxide, the pre-reactor material thermometer 9 of the material in the pre-reactor 11 remains within the range of 126 ± 1.5°C.

[0060] Step 4: Temperature control in the ripening stage:

[0061] After the cumulative value of the pre-reaction ethylene oxide mass flowmeter 4 reaches 7210 kg, the ethylene oxide feed valve 3 is closed, and the reaction enters the ripening stage. The set value of the pre-reaction temperature control system is automatically increased to 117°C, and other control parameters of the temperature control system remain unchanged. In this stage, the temperature control system is used to maintain that the pre-reactor material thermometer 9 of the material in the pre-reactor 11 does not exceed 128°C. Since no more ethylene oxide is dropped, the reaction intensity decreases, and coupled with the increase in the set value of the temperature controller, both the hot water valve 5 of the circulation heat exchanger and the cold water valve 6 of the circulation heat exchanger will be in the closed state. The entire ripening process lasts for 30 minutes, and the intermediate product after the pre-reactor is ripened enters the main reactor for further reaction.

[0062] The main reaction temperature control system includes the following steps:

[0063] Step 1: Feeding and heating up of the main reactor:

[0064] Open the intermediate feed valve 14 of the main reactor to add the intermediate to the main reactor 30, which is measured by the intermediate mass flowmeter 15. After the liquid level gauge 27 of the main reactor material monitors that the liquid level in the main reactor 30 reaches 20%, open the inlet valve 32 of the small circulation pump of the main reactor to start the small circulation pump 29. The intermediate in the main reactor 30 begins to circulate through the small circulation heat exchanger 24, and this circulation is the small circulation of the main reactor; after the small circulation is established, when the liquid level gauge 27 of the main reactor material monitors that the liquid level reaches 21%, open the inlet valve 31 of the large circulation pump of the main reactor to start the large circulation pump 28. The intermediate in the main reactor 30 begins to circulate through the large circulation heat exchanger 20, and this circulation is the large circulation of the main reactor; after both the small circulation and the large circulation of the main reactor are started, when the cumulative value of the intermediate mass flowmeter 15 reaches 7180 kg, close the intermediate feed valve 14 of the main reactor, open the hot water valve 22 of the small circulation heat exchanger and the hot water valve 18 of the large circulation heat exchanger to introduce hot water into the shell sides of the small circulation heat exchanger 24 and the large circulation heat exchanger 20 respectively, to heat up the intermediate in the tube sides of the circulation heat exchangers. After the main reactor material thermometer 26 in the main reactor 30 monitors that the temperature of the intermediate reaches 95 °C, open the ethylene oxide feed valve 16 of the main reactor and drip ethylene oxide into the main reactor 30. The ethylene oxide feed valve 16 of the main reactor controls the flow rate of the ethylene oxide mass flowmeter 17 at 10500 kg / h.

[0065] Step 2: Start the automatic temperature control system of the main reactor:

[0066] While the ethylene oxide is being dripped into the main reactor, the automatic temperature control systems of the main reaction small circulation and the main reaction large circulation are started. The monitored value of the outlet thermometer 21 of the large circulation heat exchanger 20 of the large circulation heat exchanger is used as the measured value of the large circulation temperature control system, and the set value of the large circulation temperature control system is set at 119 °C. The monitored value of the outlet thermometer 25 of the small circulation heat exchanger 24 of the small circulation heat exchanger is used as the measured value of the small circulation temperature control system, and the set value of the small circulation temperature control system is set at 119 °C. The large circulation temperature control system outputs to control the hot water valve 18 and the cold water valve 19 of the large circulation heat exchanger, and the small circulation temperature control system outputs to control the hot water valve 22 and the cold water valve 23 of the small circulation heat exchanger. The corresponding relationship is as follows in the table:

[0067]

[0068]

[0069] The temperature control system controls the ratio of hot water and cold water, and controls the water temperature entering the shells of the large-circulation heat exchanger 20 and the small-circulation heat exchanger 24. Through the adjustment of the temperature control system, the outlet thermometers 21 of the large-circulation heat exchanger and 25 of the small-circulation heat exchanger are finally controlled at 119 ± 2 °C. After the outlet temperatures of the large-circulation heat exchanger 20 and the small-circulation heat exchanger 24 are stabilized, the main reaction kettle material thermometer 26 of the reaction materials in the main reaction kettle 30 is constant at 127 ± 1.5 °C.

[0070] Step 3: Temperature control in the aging stage:

[0071] After the cumulative value of the main reaction ethylene oxide mass flowmeter 17 reaches 26960 kg, the ethylene oxide feed valve 16 of the main reaction kettle is closed, and the reaction enters the aging stage. The set value of the main reaction temperature control system is automatically increased to 123 °C, and other control parameters of the temperature control system remain unchanged. During this stage, the temperature of the materials in the main reaction kettle 30, the main reaction kettle material thermometer 26, does not exceed 130 °C, and the entire aging process lasts for 30 minutes. Example 2

[0072] A method for automatically controlling the temperature of a polyether monomer reaction kettle, including the action steps of a pre-reaction temperature control system and a main-reaction temperature control system. It is characterized in that the pre-reaction temperature control system directly controls the temperature of the circulating materials in the pre-reaction kettle 11 and indirectly controls the reaction temperature of the pre-reaction kettle 11. After the pre-reaction kettle 11 produces qualified intermediates, it enters the action of the main-reaction temperature control system. The main-reaction temperature control system simultaneously controls the temperatures of the double-circulating materials in the main-reaction kettle 30 and indirectly controls the reaction temperature of the main-reaction kettle 30.

[0073] The action steps of the pre-reaction temperature control system include the following steps:

[0074] Step 1: Feeding and heating up the pre-reaction kettle:

[0075] Open the chain initiator feed valve 1 to add the chain initiator to the pre-reaction kettle 11, which is metered by the chain initiator mass flowmeter 2. When the pre-reaction kettle material level gauge 10 monitors that the liquid level of the pre-reaction kettle 11 reaches 7%, open the inlet valve 12 of the circulation pump to start the pre-reaction kettle material circulation pump 13. The chain initiator in the pre-reaction kettle starts to circulate through the pre-reaction kettle circulation heat exchanger 7. After the cumulative value of the chain initiator mass flowmeter 2 reaches 1410 kg, close the chain initiator feed valve 1, open the hot water valve 5 of the circulation heat exchanger to introduce hot water into the shell of the pre-reaction kettle circulation heat exchanger 7, and heat up the chain initiator in the tube layer of the pre-reaction kettle circulation heat exchanger 7. When the pre-reaction kettle material thermometer 9 monitors that the temperature of the chain initiator in the pre-reaction kettle 11 rises to 90 °C, open the ethylene oxide feed valve 3 and drip ethylene oxide into the pre-reaction kettle 11, and adjust the ethylene oxide feed valve 3 to control the flow rate of the pre-reaction kettle ethylene oxide mass flowmeter 4 at 2000 kg / h.

[0076] Step 2: Start the automatic control system for the temperature of the pre-reactor:

[0077] While ethylene oxide is being added dropwise to the pre-reactor 11, the temperature control system of the pre-reactor is put into automatic operation, and the set value of the temperature control system is automatically set to 89.5 °C. Ethylene oxide is continuously added dropwise automatically relying on the ethylene oxide feed valve 3 and the ethylene oxide mass flowmeter 4 of the pre-reactor. The temperature control system of the pre-reactor uses the measured value of the thermometer 8 at the outlet of the circulation heat exchanger of the pre-reactor circulation heat exchanger 7 as the measured value of the temperature control system. The output of the temperature control system controls the opening degrees of the hot water valve 5 and the cold water valve 6 of the circulation heat exchanger. The corresponding relationship is as follows in the table:

[0078]

[0079] The temperature control system controls the ratio of hot water and cold water, and thus controls the water temperature entering the shell layer of the pre-reactor circulation heat exchanger 7. Through the adjustment of the temperature control system, the outlet temperature 8 of the circulation heat exchanger is finally controlled within the range of 89.5 ± 2 °C. After the outlet temperature 8 of the pre-reactor circulation heat exchanger 7 stabilizes, the thermometer 9 of the pre-reaction materials in the pre-reactor 11 is within the range of 101 ± 1.5 °C.

[0080] Step 3: Anti-overtemperature and leading control of the pre-reactor:

[0081] During the process of adding ethylene oxide dropwise to the pre-reactor 11, when the thermometer 9 of the pre-reaction materials in the pre-reactor monitors that the temperature exceeds 102 °C, the opening degree of the ethylene oxide feed valve 3 will automatically decrease, and the measured value of the ethylene oxide mass flowmeter 4 of the pre-reactor decreases at a flow rate of 300 kg / h. The reaction intensity of the materials in the pre-reactor 11 weakens, and the thermometer 9 of the pre-reaction materials in the reaction kettle stops rising. When the temperature control system detects a downward trend in the thermometer 9 of the pre-reaction materials in the pre-reactor, the ethylene oxide feed valve 3 returns to the original opening degree. During the entire process of adding ethylene oxide dropwise in the pre-reaction, the thermometer 9 of the pre-reaction materials in the pre-reactor 11 is maintained within the range of 101 ± 1.5 °C.

[0082] Step 4: Temperature control in the ripening stage:

[0083] After the cumulative value of the pre-reaction ethylene oxide mass flowmeter 4 reaches 6980 kg, the ethylene oxide feed valve 3 is closed, and the reaction enters the aging stage. The set value of the pre-reaction temperature control system is automatically increased to 93 °C, and other control parameters of the temperature control system remain unchanged. During this stage, the material in the pre-reaction kettle 11 is maintained by the temperature control system so that the pre-reaction kettle material thermometer 9 does not exceed 105 °C. Since no ethylene oxide is continuously added, the reaction intensity decreases. Coupled with the increase in the set value of the temperature controller, both the hot water valve 5 and the cold water valve 6 of the circulating heat exchanger will be in the closed state. The entire aging process lasts for 30 minutes, and the intermediate after aging in the pre-reaction kettle enters the main reaction kettle for further reaction.

[0084] The main reaction temperature control system includes the following steps:

[0085] Step 1: Feeding and heating up in the main reaction kettle:

[0086] Open the intermediate feed valve 14 of the main reaction kettle to add the intermediate to the main reaction kettle 30, which is measured by the intermediate mass flowmeter 15. After the main reaction kettle material level gauge 27 monitors that the liquid level in the main reaction kettle 30 reaches 20%, open the inlet valve 32 of the small circulation pump of the main reaction kettle to start the small circulation pump 29. The intermediate in the main reaction kettle 30 begins to circulate through the small circulation heat exchanger 24. This circulation is the small circulation of the main reaction kettle; after the small circulation is established, when the main reaction kettle material level gauge 27 monitors that the liquid level reaches 21%, open the inlet valve 31 of the large circulation pump of the main reaction kettle to start the large circulation pump 28. The intermediate in the main reaction kettle 30 begins to circulate through the large circulation heat exchanger 20. This circulation is the large circulation of the main reaction kettle; after both the small circulation and the large circulation of the main reaction kettle are started, after the cumulative value of the intermediate mass flowmeter 15 reaches 7180 kg, close the intermediate feed valve 14 of the main reaction kettle, and open the hot water valve 22 of the small circulation heat exchanger and the hot water valve 18 of the large circulation heat exchanger to introduce hot water into the shell sides of the small circulation heat exchanger 24 and the large circulation heat exchanger 20 respectively to heat up the intermediate in the tube sides of the circulation heat exchanger. After the main reaction kettle material thermometer 26 in the main reaction kettle 30 monitors that the intermediate temperature reaches 95 °C, open the ethylene oxide feed valve 16 of the main reaction kettle to drip ethylene oxide into the main reaction kettle 30. The ethylene oxide feed valve 16 of the main reaction kettle controls the flow rate of the ethylene oxide mass flowmeter 17 at 10500 kg / h.

[0087] Step 2: Start the automatic temperature control system of the main reaction kettle:

[0088] While ethylene oxide is being added dropwise to the main reaction kettle, the automatic temperature control systems for the main reaction small circulation and the main reaction large circulation are started. The monitored value of the thermometer 21 at the outlet of the large circulation heat exchanger 20 of the large circulation heat exchanger is used as the measured value of the large circulation temperature control system. The set value of the large circulation temperature control system is set to 116 °C. The monitored value of the thermometer 25 at the outlet of the small circulation heat exchanger 24 of the small circulation heat exchanger is used as the measured value of the small circulation temperature control system. The set value of the small circulation temperature control system is set to 115 °C. The large circulation temperature control system outputs to control the hot water valve 18 and the cold water valve 19 of the large circulation heat exchanger, and the small circulation temperature control system outputs to control the hot water valve 22 and the cold water valve 23 of the small circulation heat exchanger. The corresponding relationship is as follows in the table:

[0089]

[0090]

[0091] The temperature control system controls the ratio of hot water and cold water, controls the water temperature entering the shell layers of the large circulation heat exchanger 20 and the small circulation heat exchanger 24. Through the adjustment of the temperature control system, finally, the thermometer 21 at the outlet of the large circulation heat exchanger is controlled within 116 ± 2 °C, and the thermometer 25 at the outlet of the small circulation heat exchanger is controlled within 115 ± 2 °C. After the outlet temperature of the large circulation heat exchanger 20 and the outlet temperature of the small circulation heat exchanger 24 are stable, the thermometer 26 of the reaction materials in the main reaction kettle 30 is kept constant at 123 ± 1.5 °C.

[0092] Step 3: Temperature control in the aging stage:

[0093] After the cumulative value of the mass flowmeter 17 of the ethylene oxide in the main reaction reaches 26960 kg, the ethylene oxide feed valve 16 of the main reaction kettle is closed, and the reaction enters the aging stage. The set value of the main reaction temperature control system is automatically increased to 120 °C, and other control parameters of the temperature control system remain unchanged. In this stage, the temperature of the materials in the main reaction kettle 30, the thermometer 26 of the main reaction kettle materials, does not exceed 125 °C, and the entire aging process lasts for 30 minutes. Example 3

[0094] A method for automatically controlling the temperature of a polyether monomer reaction kettle, including the action steps of a pre-reaction temperature control system and the action steps of a main reaction temperature control system. It is characterized in that the pre-reaction temperature control system directly controls the temperature of the circulating materials in the pre-reaction kettle 11 and indirectly controls the reaction temperature of the pre-reaction kettle 11. After the pre-reaction kettle 11 produces qualified intermediates, it enters the action of the main reaction temperature control system. The main reaction temperature control system simultaneously controls the temperature of the double-circulating materials in the main reaction kettle 30 and indirectly controls the reaction temperature of the main reaction kettle 30.

[0095] The action steps of the pre-reaction temperature control system include the following steps:

[0096] Step 1: Feeding and heating up the pre-reactor:

[0097] Open the chain initiator feed valve 1 to add the chain initiator to the pre-reactor 11, which is metered by the chain initiator mass flowmeter 2. When the liquid level gauge 10 of the pre-reactor material monitors that the liquid level of the pre-reactor 11 reaches 7%, open the inlet valve 12 of the circulation pump and start the pre-reactor material circulation pump 13. The chain initiator in the pre-reactor starts to circulate through the pre-reactor circulation heat exchanger 7. After the cumulative value of the chain initiator mass flowmeter 2 reaches 1710 kg, close the chain initiator feed valve 1, open the hot water valve 5 of the circulation heat exchanger to introduce hot water into the shell side of the pre-reactor circulation heat exchanger 7, and heat up the chain initiator in the tube side of the pre-reactor circulation heat exchanger 7. When the pre-reactor material thermometer 9 monitors that the temperature of the chain initiator in the pre-reactor 11 rises to 98 °C, open the ethylene oxide feed valve 3 and drip ethylene oxide into the pre-reactor 11. Adjust the ethylene oxide feed valve 3 to control the flow rate of the pre-reactor ethylene oxide mass flowmeter 4 at 2300 kg / h.

[0098] Step 2: Start the automatic temperature control system of the pre-reactor:

[0099] While dripping ethylene oxide into the pre-reactor 11, the automatic temperature control system of the pre-reactor is put into operation, and the set value of the temperature control system is automatically set to 101 °C. Ethylene oxide continues to be automatically dripped relying on the ethylene oxide feed valve 3 and the pre-reactor ethylene oxide mass flowmeter 4. The automatic temperature control system of the pre-reactor takes the monitored value of the outlet thermometer 8 of the pre-reactor circulation heat exchanger 7 as the measured value of the temperature control system. The output of the temperature control system controls the opening degrees of the hot water valve 5 and the cold water valve 6 of the circulation heat exchanger. The corresponding relationship is as follows in the table:

[0100]

[0101] The temperature control system controls the ratio of hot water and cold water, and thus controls the water temperature entering the shell side of the pre-reactor circulation heat exchanger 7. Through the adjustment of the temperature control system, finally control the outlet temperature 8 of the circulation heat exchanger within the range of 101 ± 2 °C. After the outlet material temperature 8 of the pre-reactor circulation heat exchanger 7 is stable, the pre-reactor material thermometer 9 of the reaction material in the pre-reactor 11 is within the range of 111 ± 1.5 °C.

[0102] Step 3: Pre-reactor over-temperature prevention and advanced control:

[0103] During the process of adding ethylene oxide dropwise to the pre-reactor 11, when the pre-reactor material thermometer 9 monitors that the temperature exceeds 113°C, the ethylene oxide feed valve 3 will automatically reduce its opening degree, the measured value of the ethylene oxide mass flowmeter 4 in the pre-reactor will decrease by a flow rate of 600 kg / h, the reaction intensity of the material in the pre-reactor 11 will weaken, and the temperature of the material thermometer 9 in the pre-reactor of the reaction kettle will stop rising. When the temperature control system detects a downward trend in the pre-reactor material thermometer 9, the ethylene oxide feed valve 3 will return to its original opening degree. During the entire process of dropwise addition of pre-reaction ethylene oxide, the temperature of the pre-reactor material thermometer 9 in the pre-reactor 11 is maintained within the range of 111 ± 1.5°C.

[0104] Step 4: Temperature control in the curing stage:

[0105] After the cumulative value of the pre-reaction ethylene oxide mass flowmeter 4 reaches 6680 kg, the ethylene oxide feed valve 3 is closed, and the reaction enters the curing stage. The set value of the pre-reaction temperature control system is automatically increased to 105°C, and other control parameters of the temperature control system remain unchanged. In this stage, the temperature control system is used to maintain the temperature of the material thermometer 9 in the pre-reactor 11 not exceeding 115°C. Since no more ethylene oxide is added dropwise, the reaction intensity decreases. Coupled with the increase in the set value of the temperature controller, both the hot water valve 5 and the cold water valve 6 of the circulating heat exchanger will be in the closed state. The entire curing process lasts for 30 minutes, and the intermediate product after curing in the pre-reactor enters the main reactor for further reaction.

[0106] The main reaction temperature control system includes the following steps:

[0107] Step 1: Feeding and heating up the main reactor:

[0108] Open the intermediate feed valve 14 of the main reactor to add the intermediate to the main reactor 30, which is measured by the intermediate mass flowmeter 15. After the liquid level gauge 27 of the main reactor material monitors that the liquid level of the main reactor 30 reaches 20%, open the inlet valve 32 of the small circulation pump of the main reactor to start the small circulation pump 29. The intermediate in the main reactor 30 begins to circulate through the small circulation heat exchanger 24. This circulation is the small circulation of the main reactor. After the small circulation is established, when the liquid level gauge 27 of the main reactor material monitors that the liquid level reaches 21%, open the inlet valve 31 of the large circulation pump of the main reactor to start the large circulation pump 28. The intermediate in the main reactor 30 begins to circulate through the large circulation heat exchanger 20. This circulation is the large circulation of the main reactor. After both the small circulation and the large circulation of the main reactor are started, when the cumulative value of the intermediate mass flowmeter 15 reaches 7180 kg, close the intermediate feed valve 14 of the main reactor, and open the hot water valve 22 of the small circulation heat exchanger and the hot water valve 18 of the large circulation heat exchanger to introduce hot water into the shell sides of the small circulation heat exchanger 24 and the large circulation heat exchanger 20 respectively, to heat up the intermediate in the tube sides of the circulation heat exchangers. After the main reactor material thermometer 26 in the main reactor 30 monitors that the temperature of the intermediate reaches 95 °C, open the ethylene oxide feed valve 16 of the main reactor and drip ethylene oxide into the main reactor 30. The ethylene oxide feed valve 16 of the main reactor controls the flow rate of the ethylene oxide mass flowmeter 17 at 8500 kg / h.

[0109] Step 2: Start the automatic temperature control system of the main reactor:

[0110] While the ethylene oxide is being dripped into the main reactor, the automatic temperature control systems of the main reaction small circulation and the main reaction large circulation are started. The monitored value of the outlet thermometer 21 of the large circulation heat exchanger 20 of the large circulation heat exchanger is used as the measured value of the large circulation temperature control system. The set value of the large circulation temperature control system is set to 117 °C. The monitored value of the outlet thermometer 25 of the small circulation heat exchanger 24 of the small circulation heat exchanger is used as the measured value of the small circulation temperature control system. The set value of the small circulation temperature control system is set to 117 °C. The large circulation temperature control system outputs to control the hot water valve 18 and the cold water valve 19 of the large circulation heat exchanger. The small circulation temperature control system outputs to control the hot water valve 22 and the cold water valve 23 of the small circulation heat exchanger. The corresponding relationship is as follows in the table:

[0111]

[0112]

[0113] The temperature control system controls the ratio of hot water and cold water, and controls the water temperature entering the shell sides of the large circulation heat exchanger 20 and the small circulation heat exchanger 24. Through the adjustment of the temperature control system, finally control the thermometer 21 at the outlet of the large circulation heat exchanger to be 117 ± 2 °C, and the thermometer 25 at the outlet of the small circulation heat exchanger to be 117 ± 2 °C. After the outlet temperatures of the large circulation heat exchanger 20 and the small circulation heat exchanger 24 are stable, the thermometer 26 of the reaction materials in the main reactor 30 is constant at 122 ± 1.5 °C.

[0114] Step 3: Temperature control in the curing stage:

[0115] After the cumulative value of the mass flowmeter 17 of the main reaction ethylene oxide reaches 26980 kg, close the ethylene oxide feed valve 16 of the main reactor. The reaction enters the curing stage, and the set value of the main reaction temperature control system is automatically increased to 119 °C, and other control parameters of the temperature control system remain unchanged. In this stage, the temperature of the materials in the main reactor 30, the thermometer 26 of the main reactor materials, does not exceed 125 °C, and the entire curing process lasts for 30 minutes.

[0116] It can be seen from Examples 1, 2, and 3 that the present invention is applicable to the production of various polyether monomers. Whether it is allyl alcohol polyoxyethylene ether or isopentenol polyoxyethylene ether, only by slightly adjusting the control system parameters and the control points of the valves, the stable control of the reactor temperature can be achieved. Compared with the original control scheme, the stability and repeatability of the reactor temperature are significantly improved, and it has feasibility and applicability.

[0117] In addition, it should be understood that although this specification is described according to the embodiments, not every embodiment only contains an independent technical solution. This narrative way of the specification is only for clarity. Those skilled in the art should regard the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. An automatic temperature control method for a polyether monomer reaction kettle, including the action steps of a pre-reaction temperature control system and the action steps of a main-reaction temperature control system, characterized in that, The pre-reaction temperature control system directly controls the temperature of the circulating material in the pre-reaction kettle (11) and indirectly controls the reaction temperature of the pre-reaction kettle (11). After the pre-reaction kettle (11) produces qualified intermediates, it enters the main-reaction temperature control system. The main-reaction temperature control system simultaneously controls the temperatures of the double-circulating materials in the main-reaction kettle (30) and indirectly controls the reaction temperature of the main-reaction kettle (30). The double circulation includes the small circulation and the large circulation of the main-reaction kettle; The main-reaction temperature control system includes the following steps: Step 1: Feeding and heating up the main-reaction kettle: Open the intermediate feed valve (14) of the main-reaction kettle to add intermediates to the main-reaction kettle (30), which is measured by the intermediate mass flowmeter (15). After the main-reaction kettle material level gauge (27) monitors that the liquid level in the main-reaction kettle (30) reaches 15 - 25%, open the inlet valve (32) of the small circulation pump of the main-reaction kettle to start the small circulation pump (29). The intermediates in the main-reaction kettle (30) start to circulate through the small circulation heat exchanger (24). This circulation is the small circulation of the main-reaction kettle; After the small circulation is established, when the main-reaction kettle material level gauge (27) monitors that the liquid level reaches 20 - 30%, open the inlet valve (31) of the large circulation pump of the main-reaction kettle to start the large circulation pump (28). The intermediates in the main-reaction kettle (30) start to circulate through the large circulation heat exchanger (20). This circulation is the large circulation of the main-reaction kettle; After the cumulative value of the intermediate mass flowmeter (15) reaches 4000 - 8000 kg, close the intermediate feed valve (14) of the main-reaction kettle, and open the hot water valve (22) of the small circulation heat exchanger and the hot water valve (18) of the large circulation heat exchanger to introduce hot water into the shells of the small circulation heat exchanger (24) and the large circulation heat exchanger (20) respectively, to heat up the intermediates in the tube layers of the circulation heat exchangers. After the main-reaction kettle material thermometer (26) in the main-reaction kettle (30) monitors that the intermediate temperature reaches 85 - 100 °C, open the ethylene oxide feed valve (16) of the main-reaction kettle and drip ethylene oxide into the main-reaction kettle (30). The ethylene oxide feed valve (16) of the main-reaction kettle controls the flow rate of the ethylene oxide mass flowmeter (17) at 0 - 12000 kg / h; Step 2: Start the automatic temperature control system of the main-reaction kettle: While ethylene oxide is being added dropwise to the main reaction kettle, the automatic temperature control systems for the small and large main reaction cycles are started. The monitored value of the thermometer (21) at the outlet of the large circulation heat exchanger of the large circulation heat exchanger (20) is used as the measured value for the large circulation temperature control system. The set value of the large circulation temperature control system is usually in the range of 115 - 125 °C. The monitored value of the thermometer (25) at the outlet of the small circulation heat exchanger of the small circulation heat exchanger (24) is used as the measured value for the small circulation temperature control system. The set value of the small circulation temperature control system is usually in the range of 110 - 125 °C. The large circulation temperature control system outputs to control the hot water valve (18) and the cold water valve (19) of the large circulation heat exchanger, and the small circulation temperature control system outputs to control the hot water valve (22) and the cold water valve (23) of the small circulation heat exchanger to control the ratio of hot water and cold water, and to control the water temperature entering the shell sides of the large circulation heat exchanger (20) and the small circulation heat exchanger (24). Through the adjustment of the temperature control system, finally, the thermometer (21) at the outlet of the large circulation heat exchanger and the thermometer (25) at the outlet of the small circulation heat exchanger are controlled within ±2 °C of the set value of the temperature control system. After the outlet temperature of the large circulation heat exchanger (20) and the outlet temperature of the small circulation heat exchanger (24) are stabilized, the thermometer (26) of the reaction materials in the main reaction kettle (30) is kept constant within the range of ±1.5 °C of the target temperature; Step 3: Temperature control in the aging stage: After the cumulative value of the mass flowmeter (17) of the ethylene oxide in the main reaction reaches 10000 - 36000 kg, the ethylene oxide feed valve (16) of the main reaction kettle is closed, and the reaction enters the aging stage. The set value of the main reaction temperature control system is automatically increased by 2 - 8 °C on the original basis, and other control parameters of the temperature control system remain unchanged. In this stage, the thermometer (26) of the materials in the main reaction kettle (30) is controlled at 120 - 160 °C, and the entire aging process lasts for 20 - 90 min.

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