Method for preparing a hydroxyalkyl acrylate and system for preparing same

Abstract

The application discloses a preparation method and a preparation system of a hydroxyalkyl acrylate, and comprises the following steps: S1, raw materials of acrylic acid and a catalyst are added into a condensation reaction kettle (200), the catalyst is zinc chloride and copper powder which are compounded according to a mass ratio of (1-5):1, stirring is started, steam heating is used to heat to 80 DEG C, then ethylene oxide is slowly introduced into the reaction kettle, the reaction temperature is controlled to be 90+ / -5 DEG C, after the addition of the ethylene oxide is completed, the reaction is kept for half an hour, and a condensation product of hydroxyethyl acrylate is obtained. The application overcomes the defects of the prior art, is reasonable in design, uses an alternating type of a scraped film and a removal mode of attachments, avoids causing material loss, and selects a suitable attachment removal mode according to the attachment degree of the attachments, so that the service life of parts is not affected, and the application has high social use value and application prospect.

Description

Technical Field

[0001] This invention relates to the field of hydroxyalkyl acrylate preparation technology, and in particular to a method and system for preparing hydroxyalkyl acrylate. Background Technology

[0002] Hydroxyalkyl acrylates include hydroxyethyl acrylate and hydroxypropyl acrylate. During the production process, condensation and refining are usually used. During the production process, a certain amount of distillation residue is generated through evaporation. The residue still contains a certain amount of product. Directly disposing of it as waste would result in material waste.

[0003] In existing production processes, distillation residue is fed into a thin-film evaporator for further evaporation to collect the product, effectively increasing product yield. However, during the evaporation process, residues adhere to the inner wall and scraper of the evaporator. These residues are difficult to clean after prolonged use, requiring disassembly of the entire device or cleaning with specific chemical solvents. These methods cause some damage to the equipment and are time-consuming and labor-intensive, directly impacting production efficiency.

[0004] To address this issue, the inventors have designed and developed a method and system for preparing hydroxyalkyl acrylates, which can solve the problem of unremovable deposits generated during evaporation processes. Summary of the Invention

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A method for preparing a hydroxyalkyl acrylate includes the following steps:

[0007] S1: Add raw material acrylic acid and catalyst to condensation reactor (200). The catalyst is zinc chloride and copper powder mixed in a mass ratio of (1-5):1. Start stirring and heat with steam to 80°C. Then slowly introduce ethylene oxide into the reactor and control the reaction temperature at 90±5°C. After the ethylene oxide is added, keep the reaction at the temperature for half an hour to obtain the condensation product hydroxyethyl acrylate.

[0008] S2: Add the above-mentioned hydroxyethyl acrylate to the distillation vessel (300) and process it by vacuum distillation. When the steam temperature rises to 105±5℃, start collecting the product to obtain the hydroxyethyl acrylate product. The distillation residue enters the evaporation cylinder (1) and steam at 96±4℃ is introduced into the evaporation cylinder (1). Through the evaporation of steam, the residue evaporates and the evaporated product is collected. The residue after distillation is collected and sent to solid waste treatment.

[0009] S2: Add the above-mentioned hydroxyethyl acrylate to a distillation vessel and process it by vacuum distillation. When the steam temperature rises to 105±5℃, start collecting the product to obtain the finished hydroxyethyl acrylate. The distillation residue enters the evaporation cylinder and steam at 96±4℃ is introduced into the evaporation cylinder. Through the evaporation of steam, the residue evaporates. Collect the evaporated product and collect the residue after distillation for solid waste treatment.

[0010] A system for preparing hydroxyalkyl acrylate includes a condensation reactor, a distillation reactor, and an evaporation cylinder connected in sequence. The evaporation cylinder is provided with a feeding cylinder and a residue cylinder. The feeding cylinder is provided with a feeder and is connected to a gas guide pipe and a feed pipe. The residue cylinder is connected to a discharge pipe. Support frames are provided on the inner side of the feeding cylinder and the inner side of the residue cylinder. The support frames are provided with toothed rings.

[0011] The evaporation cylinder is provided with a hollow shaft, a gearbox is provided on the hollow shaft, a connecting mechanism is provided on the outside of the gearbox, a reciprocating screw is provided on the connecting mechanism, and synchronous gears that mesh and match with the gear ring are provided at both ends of the reciprocating screw;

[0012] The connecting mechanism includes a connecting frame that connects to the outside of the gearbox, a limiting frame at the other end of the connecting frame, and a support seat on the connecting frame.

[0013] Preferably, the hollow shaft is provided with a driven gear located at the upper part of the fabric cylinder, and an adjusting shaft rotatably fitted inside the hollow shaft. The driven gear is provided with a second motor connected to the adjusting shaft. The adjusting shaft is provided with a double-sided bevel gear. The gearbox is provided with an adjusting gear that meshes with the double-sided bevel gear. The adjusting gear is provided with a reciprocating screw fitted with a support base. A balance frame is threaded onto the reciprocating screw. The other end of the balance frame is provided with a limiting block that is movably fitted with a limiting frame.

[0014] Preferably, the limiting block is provided with a scraper blade and a scraper plate, the scraper blade and scraper plate are distributed at intervals, and the reciprocating screw is provided with a reciprocating mechanism;

[0015] The reciprocating mechanism includes a slider threadedly fitted with a reciprocating screw, a sleeve rod on the slider, an insert rod movably fitted on the sleeve rod, a return spring located inside the sleeve rod on the insert rod, a cleaning component connected to the other end of the insert rod, a guide block on the slider, and a guide plate connected to the cleaning component fitted inside the guide block.

[0016] Preferably, the cleaning assembly includes a cleaning mechanism for scraping off the deposits on the surface of the scraper blade, and a scraping frame for scraping off the deposits on the surface of the scraper.

[0017] Preferably, the cleaning mechanism includes a cleaning frame connected to the insertion rod, both sides of the cleaning frame are connected to guide plates, a spur gear is rotatably connected to the cleaning frame, a rotating shaft is provided on the spur gear, a transmission roller is provided on the rotating shaft, and a cleaning belt that contacts the surface of the scraper is fitted on the transmission roller.

[0018] Preferably, both the inner side of the cleaning frame and the inner side of the scraping frame are provided with guide grooves, and both sides of the scraper blade and both sides of the scraper are provided with guide strips embedded in the guide grooves.

[0019] Preferably, both sides of the scraper are provided with spur racks that mesh with and match the spur gears.

[0020] Preferably, the fabric cylinder is equipped with a first motor, and the output shaft of the first motor is equipped with a driving gear that meshes with the driven gear.

[0021] Compared with the prior art, the beneficial effects of the present invention are:

[0022] 1. The scraper blade and scraper plate can be used to clean the inner wall of the evaporator cylinder regularly. The scraping film treatment and the treatment of the deposits can be used alternately to avoid material loss caused by the scraper blade during the material scraping film treatment.

[0023] 2. By setting up the hollow shaft and the adjusting shaft, the scraper and the scraper can be driven to rotate synchronously on the inner wall of the evaporation cylinder. By using the meshing and matching between the double-sided bevel gear and the adjusting gear, the scraper and the scraper can alternately change positions, which makes it easy to adjust the positional relationship between the scraper and the scraper and the inner wall of the evaporation cylinder.

[0024] 3. The reciprocating mechanism enables the cleaning mechanism and scraping frame to scrape off the adhering materials on the surface of the scraper blade and scraper plate, preventing the material scraped off the surface of the evaporator cylinder from re-adhering to the surface of the scraper blade and scraper plate, thus improving the service life of the scraper blade and scraper plate and indirectly improving the utilization efficiency of the scraper blade and scraper plate.

[0025] 4. By setting up the cleaning mechanism, the cleaning belt can perform a friction-type wiping operation with the surface of the scraper blade through the cooperation between the rack and pinion, effectively removing stubborn deposits from the surface of the scraper blade.

[0026] In summary, this invention overcomes the shortcomings of the prior art, has a reasonable design, and uses an alternating scraping and attachment removal method to avoid material loss. Furthermore, it adapts the attachment removal method according to the degree of attachment, selecting a suitable attachment removal method without affecting the service life of the parts. It has high social value and application prospects. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 This is a schematic diagram of the process of the present invention.

[0029] Figure 2 This is a schematic diagram of the overall structure of the present invention.

[0030] Figure 3 This is a schematic diagram of the internal structure of the present invention.

[0031] Figure 4 This is a schematic diagram of the structural assembly of the residual material cylinder and the support frame in this invention.

[0032] Figure 5 This is a schematic diagram showing the installation position of the hollow shaft in this invention.

[0033] Figure 6 For this Figure 5 A schematic diagram of the structural cross-section.

[0034] Figure 7 This is a schematic diagram of the assembly structure of the scraper blade in this invention.

[0035] Figure 8 This is a schematic diagram of the structural assembly of the scraper in this invention.

[0036] Figure 9 This is a schematic diagram of the external structure of the hollow shaft in this invention.

[0037] Figure 10 This is a top sectional view of the structure of the present invention.

[0038] Figure 11 This is a schematic diagram showing the structural assembly of the reciprocating mechanism and the cleaning mechanism in this invention.

[0039] Figure 12 For this Figure 11 A schematic diagram of the structure exploded.

[0040] Figure 13 For this Figure 12 Enlarged view of the local structure at point A in the middle.

[0041] Figure 14 This is a schematic diagram showing the installation position of the straight rack in this invention.

[0042] Figure 15 This is a schematic diagram showing the structural assembly of the reciprocating mechanism and the scraper frame in this invention.

[0043] Figure 16 This is a schematic diagram of the structural position of the adjusting gear in this invention.

[0044] Figure 17 This is a schematic diagram of the connecting mechanism in this invention.

[0045] Figure 18 This is a schematic diagram of the installation position of the double-sided bevel gear in this invention.

[0046] Figure 19 This is a schematic diagram of the structural assembly of the double-sided bevel gear and the adjusting gear in this invention.

[0047] Figure 20 This is a schematic diagram of the structural assembly of the hollow shaft and the adjusting shaft in this invention.

[0048] In the diagram: 1. Evaporator cylinder; 101. Feeding cylinder; 1011. Air guide pipe; 1012. Feed pipe; 102. Residual material cylinder; 1021. Discharge pipe; 2. First motor; 201. Drive gear; 3. Support frame; 31. Gear ring; 4. Hollow shaft; 41. Driven gear; 42. Gearbox; 43. Connecting mechanism; 4301. Connecting frame; 4302. Support base; 4303. Limiting frame; 44. Reciprocating screw; 441. Synchronizing gear; 5. Adjusting shaft; 51. Second motor; 52. Double-sided bevel gear; 53. Adjusting gear; 531. Reciprocating screw; 202. Drive gear; 203. Driven gear; 204. Driven gear; 205. Driven gear; 202 ...3. Driven gear; 204. Driven gear; 205. Driven gear; 532. Lead screw; 533. Balance frame; 534. Limiting block; 6. Reciprocating mechanism; 601. Slider; 602. Sleeve rod; 603. Insert rod; 604. Return spring; 605. Guide block; 606. Guide plate; 7. Cleaning assembly; 71. Desiccation mechanism; 7101. Desiccation frame; 7102. Spur gear; 7103. Rotating shaft; 7104. Transmission roller; 7105. Desiccation belt; 72. Desiccation frame; 73. Guide groove; 8. Scraper; 81. Straight rack; 9. Scraper; 10. Guide bar; 200. Condensation reactor; 300. Distillation reactor. Detailed Implementation

[0049] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0050] Example 1

[0051] Reference Figure 1-20 A method for preparing hydroxyalkyl acrylate includes the following steps:

[0052] S1: Add 2000 kg of raw material acrylic acid and 15 kg of catalyst to the condensation reactor (200). The catalyst is a mixture of zinc chloride and copper powder in a mass ratio of 3:1. Start stirring and heat with steam to 80°C. Then slowly introduce 1306 kg of ethylene oxide into the reactor and control the reaction temperature at 90±5°C. After the ethylene oxide is added, keep the reaction at the temperature for half an hour to obtain the condensation product hydroxyethyl acrylate.

[0053] S2: Add the above-mentioned hydroxyethyl acrylate to the distillation vessel (300) and process it by vacuum distillation. When the steam temperature rises to 105±5℃, start collecting the product to obtain the hydroxyethyl acrylate product. The distillation residue enters the evaporation cylinder (1) and steam at 96±4℃ is introduced into the evaporation cylinder (1). Through the evaporation of steam, the residue evaporates and the evaporated product is collected. The residue after distillation is collected and sent to solid waste treatment.

[0054] Example 2

[0055] Reference Figure 1-20 A system for preparing hydroxyalkyl acrylate includes a condensation reactor 200, a distillation reactor 300, and an evaporation cylinder 1 connected in sequence. The evaporation cylinder 1 is provided with a feeding cylinder 101 and a residue cylinder 102. The feeding cylinder 101 is provided with a feeder that can distribute the material introduced into the feeding cylinder 101 by the feed pipe 1012, allowing the material to flow down along the inner wall of the evaporation cylinder 1. The feeding cylinder 101 is connected to a gas guide pipe 1011 and a feed pipe 1012. The residue cylinder 102 is connected to a discharge pipe 1021. Support frames 3 are provided on the inner side of both the feeding cylinder 101 and the residue cylinder 102. The support frames 3 are provided with toothed rings 31.

[0056] The evaporator cylinder 1 is provided with a hollow shaft 4, a gearbox 42 is provided on the hollow shaft 4, a connecting mechanism 43 is provided on the outside of the gearbox 42, a reciprocating screw 44 is provided on the connecting mechanism 43, and synchronous gears 441 that mesh and match with the gear ring 31 are provided at both ends of the reciprocating screw 44.

[0057] The connecting mechanism 43 includes a connecting frame 4301 that is connected to the outside of the gearbox 42. The other end of the connecting frame 4301 is provided with a limiting frame 4303. The connecting frame 4301 is provided with a support base 4302. The arrangement of the hollow shaft 4 and the driven gear 41 allows the adjusting shaft 5 with the adjusting gear 53 to be fitted inside it, so that the adjusting shaft 5 can rotate synchronously with the hollow shaft 4. This allows the adjusting shaft 5 to be in a relatively stationary state with the hollow shaft 4 when the hollow shaft 4 rotates alone.

[0058] Specifically, the hollow shaft 4 is equipped with a driven gear 41 located on the upper part of the fabric cylinder 101, and an adjusting shaft 5 rotatably fitted inside the hollow shaft 4. The driven gear 41 is equipped with a second motor 51 connected to the adjusting shaft 5. The adjusting shaft 5 is equipped with a double-sided bevel gear 52. The gearbox 42 is equipped with an adjusting gear 53 that meshes with the double-sided bevel gear 52. The adjusting gear 53 is equipped with a reciprocating screw 531 fitted to the support base 4302. A balance frame 532 is threaded onto the reciprocating screw 531. The other end of the balance frame 532 is equipped with a limiting block 533 that is movably fitted to the limiting frame 4303. The rotation of the adjusting shaft 5 inside the hollow shaft 4 is controlled by the second motor 51. The fixation between the second motor 51 and the driven gear 41 allows the second motor 51 to synchronously drive the adjusting shaft 5 to rotate inside the hollow shaft 4 when the driven gear 41 drives the hollow shaft 4 to rotate, so that the adjusting shaft 5 can be in a relatively stationary state with the hollow shaft 4.

[0059] Specifically, the limiting block 533 is provided with a scraper 8 and a scraper 9, which are distributed at intervals, and the reciprocating screw 44 is provided with a reciprocating mechanism 6;

[0060] The reciprocating mechanism 6 includes a slider 601 threadedly fitted with a reciprocating screw 44. A sleeve rod 602 is mounted on the slider 601, and an insert rod 603 is movably fitted onto the sleeve rod 602. A return spring 604 is located inside the sleeve rod 602 on the insert rod 603. The other end of the insert rod 603 is connected to a cleaning component 7. A guide block 605 is mounted on the slider 601, and a guide plate 606 connected to the cleaning component 7 is fitted inside the guide block 605. The rotation of the hollow shaft 4 indirectly drives the scraper blade 8 and scraper plate 9 to rotate inside the evaporator cylinder 1. By adjusting the rotation of the adjusting shaft 5, one of the scraper blade 8 and scraper plate 9 is adjusted to contact the inner wall of the evaporator cylinder 1, thus achieving separation of film scraping and adhesion processing. During film scraping by the scraper plate 9, the scraper blade 8 does not contact the inner wall of the evaporator cylinder 1. During scraping by the scraper blade 8, the scraper plate 9 does not contact the inner wall of the evaporator cylinder 1, thus meeting the conditions for periodic cleaning of the inner wall of the evaporator cylinder 1.

[0061] Specifically, the cleaning component 7 includes a cleaning mechanism 71 for scraping off the material adhering to the surface of the scraper blade 8, and a scraping frame 72 for scraping off the material adhering to the surface of the scraper plate 9. By setting up the cleaning mechanism 71 and the scraping frame 72, the surfaces of the scraper blade 8 and the scraper plate 9 can be cleaned, preventing a large amount of material from adhering to the surfaces of the scraper blade 8 and the scraper plate 9.

[0062] Specifically, the cleaning mechanism 71 includes a cleaning frame 7101 connected to the insertion rod 603. Both sides of the cleaning frame 7101 are connected to the guide plate 606. A spur gear 7102 is rotatably connected to the cleaning frame 7101. A rotating shaft 7103 is mounted on the spur gear 7102. A transmission roller 7104 is mounted on the rotating shaft 7103. A cleaning belt 7105, which contacts the surface of the scraper blade 8, is fitted onto the transmission roller 7104. Through the cooperation between the reciprocating mechanism 6 and the reciprocating screw 44, the cleaning mechanism 71 and the scraper frame 72 can be driven to... Do not move the scraper blade 8 and scraper 9 back and forth on their surfaces. This allows the cleaning belt 7105 to wipe away the deposits on the surface of the scraper blade 8, and the scraper frame 72 to scrape away the deposits on the surface of the scraper 9. Due to the different functions of the scraper blade 8 and scraper 9, the degree of deposits on their surfaces is different. Without damaging the surfaces of the scraper blade 8 and scraper 9, the cleaning mechanism 71 can clean the deposits on the surface of the scraper blade 8, and the scraper frame 72 can clean the deposits on the surface of the scraper 9.

[0063] Specifically, guide grooves 73 are provided on the inner side of the cleaning frame 7101 and the inner side of the scraping frame 72. Guide strips 10 are embedded in the guide grooves 73 on both sides of the scraper blade 8 and both sides of the scraper 9. The guide strips 10 can make the sliding assembly between the cleaning frame 7101 and the scraper blade 8 balanced and prevent misalignment. The sliding assembly between the scraper frame 72 and the scraper 9 can also be balanced and prevent misalignment.

[0064] Specifically, both sides of the scraper blade 8 are provided with spur racks 81 that mesh with the spur gears 7102. With the spur racks 81, when the cleaning frame 7101 moves up and down on the surface of the scraper blade 8, the spur gears 7102 can mesh with the spur racks 81, causing the transmission rollers 7104 to rotate. This allows the cleaning belt 7105 to rub and remove the deposits on the surface of the scraper blade 8, preventing stubborn deposits from damaging the surface of the scraper blade 8 through the scraping process.

[0065] Specifically, the fabric cylinder 101 is equipped with a first motor 2, and the output shaft of the first motor 2 is equipped with a drive gear 201 that meshes with the driven gear 41. Through the setting of the first motor 2, the hollow shaft 4 can rotate inside the evaporation cylinder 1 by utilizing the meshing between the drive gear 201 and the second motor 51.

[0066] Other undescribed structures are described in Example 1.

[0067] Working Principle: In this invention, the material first flows into the feeding cylinder 101 through the feeding pipe 1012. The material is distributed onto the inner wall of the evaporation cylinder 1 by the distributor inside the feeding cylinder 101. Under gravity, the material flows downwards along the inner wall of the evaporation cylinder 1. The rotation of the hollow shaft 4 causes the scraper 9 to scrape the material flowing downwards on the inner wall of the evaporation cylinder 1. The evaporated material is discharged through the air guide pipe 1011, and the waste material is discharged through the discharge pipe 1021. After the evaporation process is complete, the second motor 51 is turned on. Driven by the output shaft of the second motor 51, the adjusting shaft 5 rotates within the hollow shaft. The internal rotation of 4 is used to drive the adjustment gear 53 to rotate, thereby adjusting the position between the reciprocating screw 531 and the balance frame 532, so that the scraper 9 can move away from the inner wall of the evaporator cylinder 1 and the scraper 8 can be close to the inner wall of the evaporator cylinder 1. The scraper 8 can then contact the inner wall of the evaporator cylinder 1, and the second motor 51 can be turned off. Then, the first motor 2 drives the drive gear 201 to rotate, so that the driven gear 41 can drive the hollow shaft 4 to rotate on the inner wall of the evaporator cylinder 1, so that the scraper 8 in contact with the inner wall of the evaporator cylinder 1 can scrape off the deposits on the inner wall of the evaporator cylinder 1.

[0068] During the rotation of the scraper blade 8 or scraper 9 inside the evaporation cylinder 1, the meshing between the synchronous gear 441 and the gear ring 31 can drive the reciprocating screw 44 to rotate, thereby adjusting the height position of the reciprocating mechanism 6 on the reciprocating screw 44. This allows the reciprocating mechanism 6 to reciprocate up and down on the reciprocating screw 44. The cleaning belt 7105 can perform friction treatment on the surface of the scraper blade 8 to remove the adhering substances on the surface of the scraper blade 8. The scraper frame 72 can scrape off the adhering substances on the surface of the scraper 9.

[0069] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0070] In this invention, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," "link," and "fix" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, a direct connection, or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0071] The control method of this invention is automatic control through a controller. The control circuit of the controller can be implemented by simple programming by those skilled in the art. The power supply is also common knowledge in the art. Furthermore, since this invention is mainly used to protect mechanical devices, the control method and circuit connection will not be explained in detail here.

[0072] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A system for preparing hydroxyalkyl acrylate, comprising a condensation reactor (200), a distillation vessel (300), and an evaporation cylinder (1) connected in sequence, characterized in that: The evaporation cylinder (1) is provided with a feeding cylinder (101) and a residual material cylinder (102). The feeding cylinder (101) is connected to a gas guide pipe (1011) and a feed pipe (1012). The residual material cylinder (102) is connected to a discharge pipe (1021). The inner side of the feeding cylinder (101) and the inner side of the residual material cylinder (102) are both provided with a support frame (3). The support frame (3) is provided with a toothed ring (31). The evaporation cylinder (1) is provided with a hollow shaft (4), a gearbox (42) is provided on the hollow shaft (4), a connecting mechanism (43) is provided on the outside of the gearbox (42), a reciprocating screw (44) is provided on the connecting mechanism (43), and a synchronous gear (441) that meshes with the gear ring (31) is provided at both ends of the reciprocating screw (44). The connecting mechanism (43) includes a connecting frame (4301) connected to the outside of the gearbox (42), a limiting frame (4303) at the other end of the connecting frame (4301), and a support seat (4302) on the connecting frame (4301). The hollow shaft (4) is provided with a driven gear (41) located on the upper part of the fabric cylinder (101) and an adjusting shaft (5) rotatably fitted inside the hollow shaft (4). The driven gear (41) is provided with a second motor (51) connected to the adjusting shaft (5). The adjusting shaft (5) is provided with a double-sided bevel gear (52). The gearbox (42) is provided with an adjusting gear (53) meshing with the double-sided bevel gear (52). The adjusting gear (53) is provided with a reciprocating screw (531) fitted with the support base (4302). A balance frame (532) is threaded on the reciprocating screw (531). The other end of the balance frame (532) is provided with a limiting block (533) movably fitted with the limiting frame (4303). The limiting block (533) is provided with a scraper (8) and a scraper (9), the scraper (8) and the scraper (9) are distributed at intervals, and the reciprocating screw (44) is provided with a reciprocating mechanism (6). The reciprocating mechanism (6) includes a slider (601) threadedly fitted with a reciprocating screw (44), a sleeve rod (602) on the slider (601), a plug rod (603) movably fitted on the sleeve rod (602), a return spring (604) located inside the sleeve rod (602) on the plug rod (603), a cleaning component (7) connected to the other end of the plug rod (603), a guide block (605) on the slider (601), and a guide plate (606) connected to the cleaning component (7) fitted inside the guide block (605). The cleaning assembly (7) includes a cleaning mechanism (71) for scraping off the deposits on the surface of the scraper (8) and a scraper frame (72) for scraping off the deposits on the surface of the scraper (9). The cleaning mechanism (71) includes a cleaning frame (7101) connected to the reciprocating mechanism (6). A spur gear (7102) is rotatably connected to the cleaning frame (7101). A rotating shaft (7103) is provided on the spur gear (7102). A transmission roller (7104) is provided on the rotating shaft (7103). A cleaning belt (7105) that contacts the surface of the scraper (8) is fitted on the transmission roller (7104). The inner side of the cleaning frame (7101) and the inner side of the scraping frame (72) are provided with guide grooves (73), and the two sides of the scraper (8) and the two sides of the scraper (9) are provided with guide strips (10) embedded in the guide grooves (73).

2. The preparation system for hydroxyalkyl acrylate according to claim 1, characterized in that... The scraper (8) has a spur rack (81) on both sides that meshes with the spur gear (7102).

3. A method for preparing hydroxyalkyl acrylate, characterized in that, The preparation method, applied to the preparation system as described in claim 1 or 2, includes the following steps: S1: Add raw material acrylic acid and catalyst to condensation reactor (200). The catalyst is zinc chloride and copper powder mixed in a mass ratio of (1-5):

1. Start stirring and heat with steam to 80°C. Then slowly introduce ethylene oxide into the reactor and control the reaction temperature at 90±5°C. After the ethylene oxide is added, keep the reaction at the temperature for half an hour to obtain the condensation product hydroxyethyl acrylate. S2: Add the above-mentioned hydroxyethyl acrylate to the distillation vessel (300) and process it by vacuum distillation. When the steam temperature rises to 105±5℃, start collecting the product to obtain the hydroxyethyl acrylate product. The distillation residue enters the evaporation cylinder (1) and steam at 96±4℃ is introduced into the evaporation cylinder (1). Through the evaporation of steam, the residue evaporates and the evaporated product is collected. The residue after distillation is collected and sent to solid waste treatment.

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