Production method of low-molecular-weight polyether polyol

Abstract

The invention discloses a production method of low-molecular-weight polyether polyol, and relates to the technical field of synthesis of polyether compounds in organic chemistry, the production method of the low-molecular-weight polyether polyol is realized through production equipment of the low-molecular-weight polyether polyol, and the production equipment of the low-molecular-weight polyether polyol comprises a reaction kettle assembly, a driving mechanism is arranged in the reaction kettle assembly, a triggering mechanism is arranged on the outer side of the driving mechanism, a separation mechanism is arranged on the outer side of the triggering mechanism and divides an inner cavity of the reaction kettle assembly into an outer cavity and an inner cavity, and a uniform mixing mechanism is arranged at the bottom of the outer side of the separation mechanism. The mode of synchronously adding the propylene glycol, the low-molecular-weight polyether amine and the ethylene oxide can reduce the use amount of subsequent nitrogen and shorten the time required for nitrogen replacement, and meanwhile, the input speed of the ethylene oxide can be effectively increased, so that the production efficiency of the low-molecular-weight polyether polyol is improved.

Description

Technical Field

[0001] The invention relates to the technical field of polyether compound synthesis in organic chemistry, and in particular to a method for producing low molecular weight polyether polyol. Background Art

[0002] Polyether polyols are oligomers with ether bonds (—R—O—R—) in the main chain and more than 2 hydroxyl groups (—OH) in the terminal or side groups. They are prepared by ring-opening polymerization with olefin oxides using low molecular weight polyols, polyamines or compounds containing active hydrogen as initiators. Polyether polyols with different functionalities can be obtained depending on the number of active atoms contained in the initiator. The most commonly used polyether polyols are polyoxypropylene diol and polyoxypropylene triol.

[0003] The invention patent with authorization announcement number CN 105967983 B discloses a method for producing low molecular weight polyether polyols. Propylene glycol, glycerol or trimethylolpropane and low molecular weight polyether amine are put into a reactor, and after dehydration and nitrogen replacement three times, propylene oxide is added, and then a polymerization reaction is carried out. After the reaction is completed, the material is aged and cooled before being discharged to obtain a low molecular weight polyether polyol.

[0004] The invention uses low molecular weight polyetheramine as a catalyst, avoiding the hazardous waste containing inorganic salts generated by the refining treatment of crude products during the production of traditional polyether polyols. The low molecular weight target product polyetheramine is used as a catalyst for the raw material polyether polyol. The catalyst residue in the polyether polyol does not affect the further amination of the polyether polyol during the production of polyetheramine, and helps to improve the amination rate of the polyether polyol.

[0005] However, after actual application by technicians skilled in the art, it was found that the above production method still has some shortcomings. The most obvious one is that ethylene oxide, which is one of the raw materials and used in large amounts, is added after the reactor is nitrogen-substituted. This results in a large amount of air to be sucked out and a large amount of nitrogen to be input during the nitrogen replacement operation, which not only prolongs the time required for nitrogen replacement, but also increases the nitrogen consumption. In addition, since the amount of ethylene oxide used is large, it takes a long time to complete the input of propylene oxide after the nitrogen replacement is completed, which also has a great impact on the production efficiency of low molecular weight polyether polyols.

[0006] Therefore, it is necessary to invent a production method of low molecular weight polyether polyol to solve the above problems. Summary of the invention

[0007] The object of the present invention is to provide a method for producing a low molecular weight polyether polyol to solve the problems mentioned above.

[0008] To achieve the above object, the present invention provides the following technical solutions: a method for producing a low molecular weight polyether polyol, the method for producing a low molecular weight polyether polyol is achieved by a production device for a low molecular weight polyether polyol, the production device for a low molecular weight polyether polyol comprises a reactor assembly, a driving mechanism is arranged inside the reactor assembly, a trigger mechanism is arranged outside the driving mechanism, a partition mechanism is arranged outside the trigger mechanism, the partition mechanism partitions the inner cavity of the reactor assembly into an outer cavity and an inner cavity, and a mixing mechanism is arranged at the bottom of the outer side of the partition mechanism; The reactor assembly comprises a reactor body, a top plate, a plugging sleeve, a propylene glycol input pipe, a discharge pipe, a low molecular weight polyetheramine input pipe and a negative pressure pipe; The top plate is fixedly arranged on the top of the reactor body, the plugging sleeve is fixedly arranged through the top of the reactor body, the propylene glycol input pipe is fixedly arranged through the top of the left side of the reactor body, the discharge pipe is fixedly arranged through the bottom of the left side of the reactor body, and the low molecular weight polyetheramine input pipe and the negative pressure pipe are fixedly arranged through the top of the right side of the reactor body from top to bottom; The driving mechanism comprises a driving shaft, a driving motor, a nitrogen inlet pipe, a propylene oxide inlet pipe, an air hole and a valve; The drive shaft passes through the reactor body and the top plate and is rotatably connected to the reactor body and the top plate through bearings; the drive motor is fixedly arranged at the bottom of the reactor body and is transmission-connected to the drive shaft; the nitrogen input pipe is connected to the top of the drive shaft through a rotating joint; the propylene oxide input pipe is connected to the bottom of the drive shaft through a rotating joint; the air hole is opened at the top of the front side of the drive shaft; and the valve is fixedly nested at the bottom of the front side of the drive shaft.

[0009] Preferably, the trigger mechanism includes a lifting plate, a guide rod, a connecting sleeve, a rotating plate, a lever, a trigger sleeve, a first avoidance hole, a second inevitable hole and an avoidance groove.

[0010] Preferably, the lifting plate is sleeved on the outside of the driving shaft and is transmission-connected to the driving shaft through a reciprocating thread, the guide rod is fixedly arranged on the top of the lifting plate, one end of the connecting sleeve is rotationally connected to the lifting plate through a bearing and the other end is rotationally connected to the rotating plate through a bearing, the rotating plate is slidingly nested on the outside of the driving shaft along the vertical direction, the shifting rod is fixedly arranged on the side of the rotating plate, the trigger sleeve is slidingly sleeved on the outside of the driving shaft and is fixedly connected to the rotating plate, and the first avoidance hole, the second inevitable hole and the avoidance groove are sequentially opened on the front side of the trigger sleeve from top to bottom.

[0011] Preferably, the separation mechanism comprises a separation sleeve, a movable cover, an inner driving groove, a pressure equalizing hole and an outer driving groove.

[0012] Preferably, the separating sleeve is slidably arranged on the inner side of the blocking sleeve, the movable cover is rotatably arranged on the top of the separating sleeve through a bearing, the inner driving groove is opened at the inner top of the separating sleeve, the shift rod is slidably arranged on the inner side of the inner driving groove, the pressure equalizing hole is penetrated and arranged in the middle of the side of the separating sleeve, and the outer driving groove is opened at the outer bottom of the separating sleeve.

[0013] Preferably, the mixing mechanism includes a rotating ring, a side plate, a driving block, a mixing rod and a discharging scraper.

[0014] Preferably, the rotating ring is rotatably nested at the bottom of the inner cavity of the reactor assembly, the side plate is fixedly arranged at the top of the rotating ring, the driving block is fixedly arranged at the top of the inner side of the side plate and slidably arranged at the inner side of the outer driving groove, a plurality of mixing rods are arranged, and the plurality of mixing rods are evenly fixedly arranged on the outer side of the side plate, and the discharging scraper is fixedly arranged at the bottom of the outer side of the side plate.

[0015] Preferably, the production method of the low molecular weight polyether polyol specifically comprises the following steps: S1, injecting propylene glycol and low molecular weight polyetheramine into the outer chamber through the propylene glycol input pipe and the discharge pipe, injecting propylene oxide into the driving shaft through the propylene oxide input pipe, and the propylene oxide entering the driving shaft flushes the valve and enters the inner chamber for storage; S2, start the driving motor, and at the same time, suck the air inside the reactor body through the negative pressure tube. After the driving motor is started, it drives the driving shaft to rotate, and the driving shaft drives the rotating disk to rotate during the rotation process. When the rotating disk rotates, the separation sleeve is driven to rotate through the lever and the inner driving groove. When the separation sleeve rotates, the side plate is driven to rotate through the outer driving groove and the driving block. When the side plate rotates, it rotates through multiple mixing rods and a discharging scraper, thereby mixing the propylene glycol and the low molecular weight polyetheramine in the outer chamber; S3, the driving shaft rotates while driving the lifting plate to rise. When the lifting plate rises, the trigger sleeve is driven to rise synchronously through the connecting sleeve and the rotating plate. When the lifting plate reaches a first threshold, the first avoidance hole is connected to the air hole. At this time, the nitrogen input into the driving shaft by the nitrogen input pipe enters the inner chamber through the air hole and the first avoidance hole, and then enters the outer chamber through the pressure equalization hole; S4. Subsequently, as the lifting plate continues to rise, the trigger sleeve drives the first avoidance hole, the second inevitable hole and the avoidance groove to be connected with the air hole in turn. During this process, the negative pressure tube continuously sucks the gas in the inner chamber and the outer chamber, thereby completing the nitrogen replacement; S5. When the lifting distance of the lifting plate reaches the second threshold, the lever moves to the top of the inner side of the inner driving groove, and the suction of the negative pressure tube is stopped at this time. Subsequently, as the lifting plate continues to rise, the lever drives the separation sleeve to rise synchronously. At this time, the bottom end of the separation sleeve is no longer in contact with the bottom of the inner cavity of the reactor body, and the propylene oxide inside the separation sleeve begins to mix with the material in the inner cavity of the reactor body through the bottom opening of the separation sleeve; S6. When the lifting distance of the lifting plate reaches the third threshold, the separation sleeve drives the pressure equalizing hole to enter the inner side of the blocking sleeve. Subsequently, as the nitrogen is continuously input, the nitrogen entering the inner side of the separation sleeve continuously presses the propylene oxide inside the separation sleeve, thereby causing the propylene oxide inside the separation sleeve to quickly flow out from the bottom opening of the separation sleeve. S7, when the lifting distance of the lifting plate reaches the fourth threshold, the trigger sleeve blocks the air hole again, thereby stopping the input of nitrogen. Subsequently, as the lifting plate continues to rise, the mixing rod and the discharging scraper continue to stir the mixed material at the bottom of the inner cavity of the reactor body; S8. When the lifting distance of the lifting plate reaches the fifth threshold, the lifting plate moves to the top of the reciprocating thread on the outside of the drive shaft. Subsequently, as the drive shaft continues to rotate, the lifting plate descends and resets. During the descent of the lifting plate, the nitrogen supply from the nitrogen inlet pipe is stopped. At this time, the material in the inner cavity of the reactor body completes the reaction to obtain low molecular weight polyether polyols.

[0016] Technical effects and advantages of the present invention: The present invention is provided with a reactor assembly, a driving mechanism, a trigger mechanism, a partitioning mechanism and a mixing mechanism, so that the trigger mechanism is driven by the reactor assembly, and then the trigger mechanism drives the mixing mechanism through the partitioning mechanism, so as to achieve mixing of propylene glycol and low molecular weight polyether amine. Subsequently, as the trigger mechanism is continuously driven, the trigger mechanism triggers the driving mechanism and the partitioning mechanism in succession in cooperation with the reactor assembly, so as to achieve nitrogen replacement and blocking of the partitioning mechanism, so as to utilize nitrogen to quickly output propylene oxide inside the partitioning mechanism. Compared with the same type of devices and methods in the prior art, the method of simultaneously adding propylene glycol, low molecular weight polyether amine and ethylene oxide in the present invention can reduce the subsequent nitrogen usage and shorten the time required for nitrogen replacement, and at the same time can effectively increase the input speed of ethylene oxide, thereby improving the production efficiency of low molecular weight polyether polyols. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic diagram of the overall front cross-sectional structure of the present invention.

[0018] Figure 2 It is a schematic diagram of the front cross-sectional structure of the reaction kettle assembly and the driving mechanism of the present invention.

[0019] Figure 3 It is a schematic diagram of the front cross-sectional structure of the trigger mechanism of the present invention.

[0020] Figure 4 It is a schematic diagram of the front cross-sectional structure of the separation mechanism of the present invention.

[0021] Figure 5 It is a schematic diagram of the front cross-sectional structure of the mixing mechanism of the present invention.

[0022] In the figure: 1. Reactor assembly; 11. Reactor body; 12. Top plate; 13. Blocking sleeve; 14. Propylene glycol inlet pipe; 15. Discharge pipe; 16. Low molecular weight polyetheramine inlet pipe; 17. Negative pressure pipe; 2. Driving mechanism; 21. Driving shaft; 22. Driving motor; 23. Nitrogen inlet pipe; 24. Propylene oxide inlet pipe; 25. Air hole; 26. Valve; 3. Trigger mechanism; 31. Lifting plate; 32. Guide To rod; 33, connecting sleeve; 34, rotating disk; 35, lever; 36, trigger sleeve; 37, first avoidance hole; 38, second inevitable hole; 39, avoidance groove; 4, separation mechanism; 41, separation sleeve; 42, movable cover; 43, inner drive groove; 44, pressure equalizing hole; 45, outer drive groove; 5, mixing mechanism; 51, rotating ring; 52, side plate; 53, drive block; 54, mixing rod; 55, discharge scraper. DETAILED DESCRIPTION

[0023] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0024] Example 1

[0025] The present invention provides Figure 1-5 A method for producing a low molecular weight polyether polyol is shown, and the method for producing a low molecular weight polyether polyol is achieved by a production device for a low molecular weight polyether polyol, and the production device for a low molecular weight polyether polyol comprises a reactor assembly 1, wherein a driving mechanism 2 is arranged inside the reactor assembly 1, a trigger mechanism 3 is arranged outside the driving mechanism 2, a partition mechanism 4 is arranged outside the trigger mechanism 3, the partition mechanism 4 partitions the inner cavity of the reactor assembly 1 into an outer chamber and an inner chamber, and a mixing mechanism 5 is arranged at the bottom of the outer side of the partition mechanism 4.

[0026] like Figure 2As shown, the reactor assembly 1 includes a reactor body 11, a top plate 12, a plugging sleeve 13, a propylene glycol input pipe 14, a discharge pipe 15, a low molecular weight polyetheramine input pipe 16 and a negative pressure pipe 17, wherein the top plate 12 is fixedly arranged on the top of the reactor body 11, the plugging sleeve 13 is fixedly penetrated through the top of the reactor body 11, the propylene glycol input pipe 14 is fixedly penetrated through the top of the left side of the reactor body 11, the discharge pipe 15 is fixedly penetrated through the bottom of the left side of the reactor body 11, and the low molecular weight polyetheramine input pipe 16 and the negative pressure pipe 17 are fixedly penetrated through the top of the right side of the reactor body 11 from top to bottom.

[0027] like Figure 2 As shown, the driving mechanism 2 includes a driving shaft 21, a driving motor 22, a nitrogen inlet pipe 23, a propylene oxide inlet pipe 24, an air hole 25 and a valve 26, wherein the driving shaft 21 passes through the reactor body 11 and the top plate 12 and is rotatably connected to the reactor body 11 and the top plate 12 through a bearing, the driving motor 22 is fixedly arranged at the bottom of the reactor body 11 and is transmission-connected to the driving shaft 21, the nitrogen inlet pipe 23 is connected to the top end of the driving shaft 21 through a rotating joint, the propylene oxide inlet pipe 24 is connected to the bottom end of the driving shaft 21 through a rotating joint, the air hole 25 is opened at the top of the front face of the driving shaft 21, and the valve 26 is fixedly nested at the bottom of the front face of the driving shaft 21.

[0028] like Figure 3 As shown, the trigger mechanism 3 includes a lifting plate 31, a guide rod 32, a connecting sleeve 33, a rotating plate 34, a lever 35, a trigger sleeve 36, a first avoidance hole 37, a second inevitable hole 38 and an avoidance groove 39, wherein the lifting plate 31 is sleeved on the outside of the driving shaft 21 and is transmission-connected to the driving shaft 21 through a reciprocating thread, the guide rod 32 is fixedly arranged on the top of the lifting plate 31, one end of the connecting sleeve 33 is rotationally connected to the lifting plate 31 through a bearing and the other end is rotationally connected to the rotating plate 34 through a bearing, the rotating plate 34 is slidingly nested on the outside of the driving shaft 21 along the vertical direction, the lever 35 is fixedly arranged on the side of the rotating plate 34, the trigger sleeve 36 is slidingly sleeved on the outside of the driving shaft 21 and is fixedly connected to the rotating plate 34, and the first avoidance hole 37, the second inevitable hole 38 and the avoidance groove 39 are sequentially opened on the front of the trigger sleeve 36 from top to bottom.

[0029] By setting the above structure, the driving motor 22 can drive the driving shaft 21 to rotate after it is started. During the rotation of the driving shaft 21, the rotating disk 34 is driven to rotate. When the rotating disk 34 rotates, the lever 35 is driven to rotate synchronously. During the rotation of the driving shaft 21, the lifting disk 31 is also driven to rise. When the lifting disk 31 rises, the trigger sleeve 36 is driven to rise synchronously through the connecting sleeve 33 and the rotating disk 34. During the rising process of the trigger sleeve 36, the first avoidance hole 37, the second inevitable hole 38 and the avoidance groove 39 are successively connected with the air hole 25. In this process, the nitrogen input into the driving shaft 21 by the nitrogen input pipe 23 successively enters the inner chamber and the outer chamber.

[0030] like Figure 4 As shown, the separation mechanism 4 includes a separation sleeve 41, a movable cover 42, an inner driving groove 43, a pressure equalizing hole 44 and an outer driving groove 45, wherein the separation sleeve 41 is slidably arranged on the inner side of the blocking sleeve 13, the movable cover 42 is rotatably arranged on the top of the separation sleeve 41 through a bearing, the inner driving groove 43 is opened at the inner top of the separation sleeve 41, the lever 35 is slidably arranged on the inner side of the inner driving groove 43, the pressure equalizing hole 44 is penetrated and arranged in the middle of the side of the separation sleeve 41, and the outer driving groove 45 is opened at the outer bottom of the separation sleeve 41.

[0031] By setting the above structure, when nitrogen is input into the separation sleeve 41, the nitrogen can enter the reactor body 11 through the pressure equalizing hole 44. When the air inside the reactor body 11 is extracted, the air inside the separation sleeve 41 can be synchronously extracted through the pressure equalizing hole 44. When the lever 35 moves to the top of the inner side of the inner driving groove 43, as the lever 35 continues to rise, the separation sleeve 41 is driven to rise synchronously, so that the bottom opening of the separation sleeve 41 is no longer blocked by the reactor body 11.

[0032] like Figure 5 As shown, the mixing mechanism 5 includes a rotating ring 51, a side plate 52, a driving block 53, a mixing rod 54 and a discharging scraper 55, wherein the rotating ring 51 is rotatably nested at the bottom of the inner cavity of the reactor assembly 1, the side plate 52 is fixedly arranged on the top of the rotating ring 51, the driving block 53 is fixedly arranged at the top of the inner side of the side plate 52 and is slidably arranged on the inner side of the outer driving groove 45, a plurality of mixing rods 54 are arranged, and the plurality of mixing rods 54 are evenly fixedly arranged on the outer side of the side plate 52, and the discharging scraper 55 is fixedly arranged at the outer bottom of the side plate 52.

[0033] By setting the above structure, when the separating sleeve 41 rotates, the separating sleeve 41 drives the side plate 52 to rotate through the outer driving groove 45 and the driving block 53. When the side plate 52 rotates, it drives multiple mixing rods 54 and the discharging scraper 55 to stir and mix the materials. In addition, during the rising process of the separating sleeve 41, the driving block 53 moves downward relatively on the inner side of the outer driving groove 45, thereby ensuring that the mixing rod 54 and the discharging scraper 55 can continue to be driven during the rising process of the separating sleeve 41.

[0034] Example 2

[0035] The production method of the low molecular weight polyether polyol specifically comprises the following steps: S1, inject propylene glycol and low molecular weight polyetheramine into the outer chamber through the propylene glycol input pipe 14 and the discharge pipe 15, inject propylene oxide into the driving shaft 21 through the propylene oxide input pipe 24, and the propylene oxide entering the driving shaft 21 will open the valve 26 and enter the inner chamber for storage; S2, start the drive motor 22, and at the same time, suck the air inside the reactor body 11 through the negative pressure tube 17. After the drive motor 22 is started, it drives the drive shaft 21 to rotate. During the rotation of the drive shaft 21, it drives the rotating disk 34 to rotate. When the rotating disk 34 rotates, it drives the separation sleeve 41 to rotate through the lever 35 and the inner drive groove 43. When the separation sleeve 41 rotates, it drives the side plate 52 to rotate through the outer drive groove 45 and the drive block 53. When the side plate 52 rotates, it rotates through the multiple mixing rods 54 and the discharging scraper 55, thereby mixing the propylene glycol and the low molecular weight polyetheramine in the outer chamber; S3, during the rotation of the driving shaft 21, the lifting plate 31 is simultaneously driven to rise. When the lifting plate 31 rises, the trigger sleeve 36 is driven to rise synchronously through the connecting sleeve 33 and the rotating plate 34. When the lifting plate 31 reaches the first threshold, the first avoidance hole 37 is connected with the air hole 25. At this time, the nitrogen input into the driving shaft 21 by the nitrogen input pipe 23 enters the inner chamber through the air hole 25 and the first avoidance hole 37, and then enters the outer chamber through the pressure equalizing hole 44; S4. Subsequently, as the lifting plate 31 continues to rise, the trigger sleeve 36 drives the first avoidance hole 37, the second inevitable hole 38 and the avoidance groove 39 to communicate with the air hole 25. During this process, the negative pressure tube 17 continues to suck the gas in the inner chamber and the outer chamber, thereby completing the nitrogen replacement; S5. When the lifting distance of the lifting plate 31 reaches the second threshold, the lever 35 moves to the top of the inner side of the inner driving groove 43, and the suction of the negative pressure tube 17 is stopped at this time. Subsequently, as the lifting plate 31 continues to rise, the lever 35 drives the separation sleeve 41 to rise synchronously. At this time, the bottom end of the separation sleeve 41 is no longer in contact with the bottom of the inner cavity of the reactor body 11, and the propylene oxide inside the separation sleeve 41 begins to mix with the material in the inner cavity of the reactor body 11 through the bottom opening of the separation sleeve 41; S6, when the lifting distance of the lifting plate 31 reaches the third threshold, the separation sleeve 41 drives the pressure equalizing hole 44 to enter the inner side of the blocking sleeve 13, and then as the nitrogen is continuously input, the nitrogen entering the inner side of the separation sleeve 41 continuously presses the propylene oxide inside the separation sleeve 41, thereby causing the propylene oxide inside the separation sleeve 41 to quickly flow out from the bottom opening of the separation sleeve 41; S7, when the lifting distance of the lifting plate 31 reaches the fourth threshold, the trigger sleeve 36 blocks the air hole 25 again, thereby stopping the input of nitrogen. Subsequently, as the lifting plate 31 continues to rise, the mixing rod 54 and the discharging scraper 55 continue to stir the mixed material at the bottom of the inner cavity of the reactor body 11; S8. When the lifting distance of the lifting plate 31 reaches the fifth threshold, the lifting plate 31 moves to the top of the reciprocating thread on the outside of the drive shaft 21. Subsequently, as the drive shaft 21 continues to rotate, the lifting plate 31 descends and resets. During the descent of the lifting plate 31, the nitrogen supply from the nitrogen input pipe 23 is stopped. At this time, the material in the inner cavity of the reactor body 11 completes the reaction to obtain a low molecular weight polyether polyol.

[0036] Finally, it should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for producing a low molecular weight polyether polyol, characterized in that: The method for producing a low molecular weight polyether polyol is achieved by using a low molecular weight polyether polyol production device, the low molecular weight polyether polyol production device comprising a reactor assembly (1), wherein a driving mechanism (2) is arranged inside the reactor assembly (1), a trigger mechanism (3) is arranged outside the driving mechanism (2), a partition mechanism (4) is arranged outside the trigger mechanism (3), the partition mechanism (4) partitions the inner cavity of the reactor assembly (1) into an outer cavity and an inner cavity, and a mixing mechanism (5) is arranged at the outer bottom of the partition mechanism (4); The reactor assembly (1) comprises a reactor body (11), a top plate (12), a plugging sleeve (13), a propylene glycol input pipe (14), a discharge pipe (15), a low molecular weight polyetheramine input pipe (16) and a negative pressure pipe (17); The top plate (12) is fixedly arranged on the top of the reactor body (11), the blocking sleeve (13) is fixedly arranged through the top of the reactor body (11), the propylene glycol input pipe (14) is fixedly arranged through the top of the left side of the reactor body (11), the discharge pipe (15) is fixedly arranged through the bottom of the left side of the reactor body (11), and the low molecular weight polyetheramine input pipe (16) and the negative pressure pipe (17) are fixedly arranged through the top of the right side of the reactor body (11) in sequence from top to bottom; The driving mechanism (2) comprises a driving shaft (21), a driving motor (22), a nitrogen inlet pipe (23), a propylene oxide inlet pipe (24), an air hole (25) and a valve (26); The driving shaft (21) passes through the reactor body (11) and the top plate (12) and is rotatably connected to the reactor body (11) and the top plate (12) via bearings; the driving motor (22) is fixedly arranged at the bottom of the reactor body (11) and is drivingly connected to the driving shaft (21); the nitrogen inlet pipe (23) is connected to the top of the driving shaft (21) via a rotating joint; the propylene oxide inlet pipe (24) is connected to the bottom of the driving shaft (21) via a rotating joint; the air hole (25) is opened at the top of the front face of the driving shaft (21); and the valve (26) is fixedly nested at the bottom of the front face of the driving shaft (21).

2. The method for producing a low molecular weight polyether polyol according to claim 1, characterized in that: The trigger mechanism (3) comprises a lifting plate (31), a guide rod (32), a connecting sleeve (33), a rotating plate (34), a shifting rod (35), a trigger sleeve (36), a first avoidance hole (37), a second inevitable hole (38) and an avoidance groove (39).

3. The method for producing a low molecular weight polyether polyol according to claim 2, characterized in that: The lifting plate (31) is sleeved and arranged on the outside of the driving shaft (21) and is transmission-connected to the driving shaft (21) via a reciprocating thread; the guide rod (32) is fixedly arranged on the top of the lifting plate (31); one end of the connecting sleeve (33) is rotationally connected to the lifting plate (31) via a bearing and the other end is rotationally connected to the rotating plate (34) via a bearing; the rotating plate (34) is slidably nested and arranged on the outside of the driving shaft (21) in a vertical direction; the shifting rod (35) is fixedly arranged on the side of the rotating plate (34); the trigger sleeve (36) is slidably sleeved and arranged on the outside of the driving shaft (21) and is fixedly connected to the rotating plate (34); the first avoidance hole (37), the second inevitable hole (38) and the avoidance groove (39) are sequentially opened on the front side of the trigger sleeve (36) from top to bottom.

4. The method for producing a low molecular weight polyether polyol according to claim 3, characterized in that: The separation mechanism (4) comprises a separation sleeve (41), a movable cover (42), an inner driving groove (43), a pressure equalizing hole (44) and an outer driving groove (45).

5. The method for producing a low molecular weight polyether polyol according to claim 4, characterized in that: The separation sleeve (41) is slidably arranged inside the blocking sleeve (13); the movable cover (42) is rotatably arranged on the top of the separation sleeve (41) via a bearing; the inner driving groove (43) is opened at the top of the inner side of the separation sleeve (41); the shifting rod (35) is slidably arranged inside the inner driving groove (43); the pressure equalizing hole (44) is penetrated and arranged in the middle of the side of the separation sleeve (41); and the outer driving groove (45) is opened at the bottom of the outer side of the separation sleeve (41).

6. The method for producing a low molecular weight polyether polyol according to claim 5, characterized in that: The mixing mechanism (5) comprises a rotating ring (51), a side plate (52), a driving block (53), a mixing rod (54) and a discharging scraper (55).

7. The method for producing a low molecular weight polyether polyol according to claim 6, characterized in that: The rotating ring (51) is rotatably nested at the bottom of the inner cavity of the reactor assembly (1); the side plate (52) is fixedly arranged at the top of the rotating ring (51); the driving block (53) is fixedly arranged at the top of the inner side of the side plate (52) and slidably arranged at the inner side of the outer driving groove (45); a plurality of mixing rods (54) are provided, and the plurality of mixing rods (54) are evenly fixedly arranged at the outer side of the side plate (52); and the discharging scraper (55) is fixedly arranged at the outer bottom of the side plate (52).

8. The method for producing a low molecular weight polyether polyol according to claim 7, characterized in that: The production method of the low molecular weight polyether polyol specifically comprises the following steps: S1, injecting propylene glycol and low molecular weight polyetheramine into the outer chamber through the propylene glycol inlet pipe (14) and the outlet pipe (15), injecting propylene oxide into the interior of the drive shaft (21) through the propylene oxide inlet pipe (24), and the propylene oxide entering the interior of the drive shaft (21) opens the valve (26) and enters the inner chamber for storage; S2, starting the driving motor (22), and at the same time sucking the air inside the reactor body (11) through the negative pressure tube (17), after the driving motor (22) is started, the driving shaft (21) is driven to rotate, and the driving shaft (21) drives the rotating disk (34) to rotate during the rotation process, and when the rotating disk (34) rotates, the separating sleeve (41) is driven to rotate through the lever (35) and the inner driving groove (43), and when the separating sleeve (41) rotates, the side plate (52) is driven to rotate through the outer driving groove (45) and the driving block (53), and when the side plate (52) rotates, the plurality of mixing rods (54) and the discharging scraper (55) are rotated, thereby mixing the propylene glycol and the low molecular weight polyetheramine in the outer chamber; S3, the driving shaft (21) drives the lifting plate (31) to rise while rotating. When the lifting plate (31) rises, the trigger sleeve (36) is driven to rise synchronously through the connecting sleeve (33) and the rotating plate (34). When the lifting plate (31) reaches a first threshold, the first avoidance hole (37) is connected to the air hole (25). At this time, the nitrogen input into the driving shaft (21) through the nitrogen input pipe (23) enters the inner chamber through the air hole (25) and the first avoidance hole (37), and then enters the outer chamber through the pressure equalizing hole (44); S4. Subsequently, as the lifting plate (31) continues to rise, the trigger sleeve (36) drives the first avoidance hole (37), the second inevitable hole (38) and the avoidance groove (39) to communicate with the air hole (25). During this process, the negative pressure tube (17) continues to suck the gas in the inner chamber and the outer chamber, thereby completing the nitrogen replacement; S5. When the lifting distance of the lifting plate (31) reaches the second threshold, the lever (35) moves to the top of the inner side of the inner driving groove (43). At this time, the suction of the negative pressure tube (17) is stopped. Subsequently, as the lifting plate (31) continues to rise, the lever (35) drives the separation sleeve (41) to rise synchronously. At this time, the bottom end of the separation sleeve (41) is no longer in contact with the bottom of the inner cavity of the reactor body (11). The propylene oxide inside the separation sleeve (41) begins to mix with the material in the inner cavity of the reactor body (11) through the bottom opening of the separation sleeve (41); S6, when the lifting distance of the lifting plate (31) reaches the third threshold, the separation sleeve (41) drives the pressure equalizing hole (44) to enter the inner side of the blocking sleeve (13), and subsequently, as the nitrogen is continuously input, the nitrogen entering the inner side of the separation sleeve (41) continuously presses the propylene oxide inside the separation sleeve (41), thereby causing the propylene oxide inside the separation sleeve (41) to quickly flow out from the bottom opening of the separation sleeve (41); S7, when the lifting distance of the lifting plate (31) reaches a fourth threshold, the trigger sleeve (36) blocks the air hole (25) again, thereby stopping the input of nitrogen, and subsequently, as the lifting plate (31) continues to rise, the mixing rod (54) and the discharge scraper (55) continue to stir the mixed material at the bottom of the inner cavity of the reactor body (11); S8. When the lifting distance of the lifting plate (31) reaches the fifth threshold, the lifting plate (31) moves to the top of the reciprocating thread on the outside of the driving shaft (21). Subsequently, as the driving shaft (21) continues to rotate, the lifting plate (31) descends and resets. During the descent of the lifting plate (31), the nitrogen supply from the nitrogen inlet pipe (23) is stopped. At this time, the material in the inner cavity of the reactor body (11) completes the reaction, and a low molecular weight polyether polyol is obtained.

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