Novel production method of pentaerythritol

Abstract

The invention provides a novel production method of pentaerythritol, which relates to the technical field of chemical products, and comprises the following steps: proportioning formaldehyde, acetaldehyde and lithium hydroxide, mixing, carrying out condensation reaction, and adding formic acid to neutralize the solution after the reaction; collecting the neutralized solution, carrying out rectification treatment, and separating out crystals; carrying out centrifugal treatment on the separated crystals, and then putting the crystals into a washing tank for washing; drying to obtain a pentaerythritol finished product; precipitating the mother liquor, washing and refluxing the filtered solution, and mixing the filtered solution with the dealdehyding solution for cyclic utilization; and concentrating, crystallizing, centrifuging, washing and drying the filtrate to obtain a lithium formate product. According to the production method of the pentaerythritol by the lithium method, the reaction conversion rate is high, and the product quality is excellent; the added value is high, and the overall economy of the production process is good; the mother liquor is completely circulated in a closed manner, and is pollution-free and environment-friendly. The automation degree is high, and the washing, overturning and discharging processes can be completed only through single power equipment.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of chemical products, in particular to a new production method of pentaerythritol. BACKGROUND

[0002] Pentaerythritol is an important polyol compound, and its production is mainly completed by aldol condensation reaction of acetaldehyde and excess formaldehyde under the action of an alkaline catalyst. The process involves the Cannizzaro reaction, and the product is obtained by crystallization, filtration and purification to obtain white crystalline solid, with high yield and high purity. In terms of application, pentaerythritol is a core raw material for manufacturing alkyd resin, and is widely used in the paint and coating industry to improve product weather resistance and gloss, and is also used as a component of polyester resin for plastics and adhesives; in the explosives field, it is a key precursor of pentaerythritol tetranitrate (PETN) for civilian blasting and military ammunition; in addition, it is also used in lubricants, plasticizers and pharmaceutical intermediates.

[0003] In the prior art, the production route of pentaerythritol basically uses formaldehyde and acetaldehyde as raw materials to carry out condensation reaction under the catalysis of sodium hydroxide or calcium hydroxide. These production processes have the following problems: 1. Although the sodium hydroxide process is mature, the by-product sodium formate cannot achieve high quality under the condition of full circulation of the mother liquor, and the value of sodium formate is low, which is a high-cost production method; 2. The calcium hydroxide process is not mature, the steps are complex, calcium formate is easy to crystallize and precipitate to block the pipeline and equipment, causing production stoppage risk; at the same time, the "calcium ash" remaining in the product at high temperature can catalyze the decomposition of pentaerythritol, resulting in a decrease in product purity. On the other hand, the washing process of the conventional pentaerythritol preparation scheme directly affects the impurities of the product, so the traditional scheme has the problems of long washing time, easy occurrence of washing dead angle, and easy blockage during discharging. SUMMARY

[0004] The present application aims to at least solve one of the technical problems in the related art. To this end, the purpose of the present application is to provide a new production method of pentaerythritol, which is simple and convenient, has no equipment blockage phenomenon, has high yield, high quality of the prepared product, high added value, and good overall economy of the production process; the mother liquor is completely closed and recycled, which is pollution-free and more friendly to the environment, and the thickness problem of the crystallized material during washing can be avoided to cause the occurrence of washing dead angle in some areas, and the degree of automation is high, only a single power equipment is needed to complete the washing, overturning and discharging processes.

[0005] To achieve the above-mentioned purpose, the present application provides a new production method of pentaerythritol, comprising the following steps:

[0006] S1, formaldehyde, acetaldehyde and lithium hydroxide are mixed after being proportioned, and a condensation reaction is carried out, then formic acid is added to neutralize the solution after the reaction; S2, the solution after neutralization is collected and subjected to rectification treatment to remove excess formaldehyde in the material; S3, after removing the excess formaldehyde, the solution is concentrated, then cooled, and crystallization is precipitated until the crystallization is precipitated; S4, the precipitated crystallization is centrifuged, then put into a washing tank, the inside of the washing tank is provided with a turnover assembly, the precipitated crystallization is stored by the turnover assembly, and pure water is injected into the flushing assembly at the top of the washing tank, the turnover assembly and the flushing assembly are controlled and operated by a driving mechanism, the driving mechanism controls the flushing assembly to move along the turnover assembly, and the precipitated crystallization is washed;

[0007] After washing, the driving mechanism is continuously controlled to drive the turnover assembly to swing quickly, the opposite clamping plates at the end of the turnover assembly are unfolded, the washed crystallization material inside the turnover assembly is thrown towards the lower side, then the washed material is collected for drying treatment to obtain a pentaerythritol product; S5, the mother liquor obtained after centrifugation of the crystallization precipitated in step S3 is precipitated, then filtered, and the filtered solution is washed back to flow and mixed with the dealding liquid for recycling; S6, the remaining filtrate is concentrated, crystallized, centrifuged, washed and dried to obtain a lithium formate product.

[0008] Further, in step S1, the molar ratio of formaldehyde, acetaldehyde and lithium hydroxide is 6-10:1:1-1.5, the reaction temperature is 30-55℃, the reaction time is 1-2 hours, and the holding time is 0.5-1 hour; after the condensation reaction, formic acid is added until the pH of the solution is adjusted to 5.5-7.5; in step S3, the cooling time is 3-6 hours.

[0009] Further, the washing tank used in step S4 comprises a driving mechanism, a flushing assembly and a turnover assembly, a discharge port is formed in the bottom of the washing tank, first magnetic plates are arranged on the top of the washing tank, a vertical plate is integrally formed in the middle of the top of the washing tank, a driving mechanism is inserted in the middle of the vertical plate, a transmission box is welded to the front end of the driving mechanism, and an electric motor is screwed to the front end of the transmission box;

[0010] The side of the driving mechanism is provided with a flushing assembly, the lower side of the flushing assembly is provided with a turnover assembly, the turnover assembly is used to store the precipitated crystallization, a water injection pipeline is connected to the end of the flushing assembly, the water injection pipeline is used to deliver pure water to the inside of the flushing assembly, and the flushing assembly is used to spray the pure water towards the position of the turnover assembly below.

[0011] Further, the driving mechanism comprises a driving shaft, a driven shaft, a driving gear and a driven gear, the output end of the motor is connected with the driving shaft, the surface of the driving shaft is key-connected with the driving gear, the two ends of the driven shaft are movably connected with the surface of the vertical plate at the top of the washing tank, and the end of the driven shaft is sleeved with a bearing, the surface of the driven shaft is key-connected with the driven gear, and the driving gear and the driven gear are engaged.

[0012] The driving gear and the driven gear are hidden in the interior of the transmission box, and the lead screw is integrally formed on the driven shaft.

[0013] Further, the driving mechanism comprises a first linkage sleeve, a second linkage sleeve and a threaded sleeve, the surface of the lead screw is sleeved with the threaded sleeve, the side edge of the threaded sleeve is partially welded and fixed, the side edge of the turnover assembly is welded with the second linkage sleeve, and the surface of the driven shaft is further sleeved with the first linkage sleeve; the side edge of the first linkage sleeve is welded with a guide rod, the number of the first linkage sleeves is two, the two ends of the guide rod are welded and fixed with different first linkage sleeves, the driven shaft is used for controlling the rotary motion of the lead screw and the first linkage sleeve, and the driving shaft is used for controlling the rotary motion of the second linkage sleeve.

[0014] Further, the driving mechanism further comprises a telescopic groove, a spring rod and a ball, the surfaces of the driving shaft and the driven shaft are both provided with the telescopic groove, the interior of the telescopic groove is both inserted with the spring rod, the tail end of the spring rod is welded with the ball, the inner walls of the first linkage sleeve and the second linkage sleeve are both provided with a groove, the ball is used for being embedded into the groove, and the ball is also used for rolling along the inner wall of the first linkage sleeve or the second linkage sleeve.

[0015] Further, the flushing assembly comprises a flow guide box, a water injection pipeline and a flow guide assembly, one end of the flow guide box is partially welded and fixed with the driving mechanism, the one end of the flow guide box is connected with the water injection pipeline, the end of the flow guide box is further welded with a limiting baffle, the interior of the flow guide box is embedded with the flow guide assembly, and the limiting baffle is used for abutting against the outer side of the first magnetic plate.

[0016] Further, the flow guide assembly comprises a flow guide plate, an end plate and an inner layer opening, the interior of the flow guide box is welded with a partition plate, the number of the flow guide plates is two, and the same end of the two flow guide plates is integrally formed with the end plate, and the surface of the end plate is provided with the inner layer opening; the tail end of the partition plate and the inner wall of the flow guide box are provided with a spacing, the partition plate abuts against the inner wall of the end plate, the tail end of the flow guide box is provided with an outer layer opening, the inner layer opening is used for being aligned with the outer layer opening, and the surface of each flow guide plate is provided with a hole.

[0017] Furthermore, the flipping assembly includes: a storage interlayer, a winding box, a gap, a mesh, a split clamping plate, and a third magnetic suction plate. The storage interlayer is provided with winding boxes at both ends, and a gap is provided at the top of the winding box. The top and bottom surfaces of the storage interlayer are provided with mesh. The split clamping plate is hinged to the end of the storage interlayer. A third magnetic suction plate is installed at the end of the inner wall of the storage interlayer. The third magnetic suction plate is used to adsorb and adhere to the inner side of the split clamping plate. The first magnetic suction plate is used to adsorb and fix the end of the storage interlayer.

[0018] Furthermore, the flipping assembly also includes: a second magnetic suction plate, a roller, and a filter membrane. Both ends of the second magnetic suction plate are connected to the filter membrane. The filter membrane is wound around the surface of the roller. The roller is embedded in the interior of the winding box. The second magnetic suction plate is pressed and adsorbed onto the surface of the storage interlayer. The surface of the second magnetic suction plate is provided with docking holes. The second magnetic suction plate is also used to adsorb and dock with the flow guiding assembly.

[0019] The technical solution provided by this invention may include the following beneficial effects:

[0020] 1. This new production method for pentaerythritol has no equipment blockage, high yield, and the reaction conversion rate of pentaerythritol series products reaches over 98%, with a total yield of 96%; the product quality is excellent (purity ≥98.0%); the by-product lithium formate has a purity greater than 98%, high added value, and good overall economic efficiency of the production process; the mother liquor is completely recycled in a closed loop, with no pollution and is environmentally friendly.

[0021] 2. In this new pentaerythritol production method, a semi-open washing tank is used to rinse the pentaerythritol crystal material to be washed with the help of a flipping component. With the help of the drive mechanism and the rinsing component, the material in a flat state can be washed on both sides, which makes the washing efficiency stronger and more efficient. It can avoid the washing dead corners caused by thickness issues. Moreover, the flipping process is highly automated, and only a single power equipment is needed to complete the flipping, washing and discharge processes.

[0022] 3. In the new production method of pentaerythritol, during the discharge process, the pentaerythritol crystal material stored inside the flipping component is accelerated and thrown towards the bottom by increasing the swing speed through the drive mechanism and by taking advantage of the centrifugal effect. This allows the material to be discharged more thoroughly from the inside of the flat flipping component. This process can also be completed automatically, and the rinsing water utilization rate is higher, reducing the amount of waste from overflow from the top.

[0023] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0024] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the following description of the embodiments taken in conjunction with the accompanying drawings, wherein:

[0025] Figure 1 This is a production flow diagram of a novel pentaerythritol production method proposed in an embodiment of the present invention;

[0026] Figure 2 This is a liquid chromatogram of pentaerythritol in a novel production method for pentaerythritol proposed in an embodiment of the present invention;

[0027] Figure 3 This is a liquid chromatogram of lithium formate, a byproduct of a novel pentaerythritol production method proposed in an embodiment of the present invention.

[0028] Figure 4 This is a structural diagram of the washing tank used in a novel pentaerythritol production method proposed in an embodiment of the present invention;

[0029] Figure 5 This is a side sectional view of the washing tank used in a novel pentaerythritol production method proposed in an embodiment of the present invention;

[0030] Figure 6 This is a schematic diagram of the installation of the rinsing assembly and the tilting assembly in a washing tank according to an embodiment of the present invention;

[0031] Figure 7 This is a schematic diagram of the rinsing assembly in a washing tank according to an embodiment of the present invention;

[0032] Figure 8 This is a schematic diagram of the structure of the tilting assembly in a washing tank according to an embodiment of the present invention;

[0033] Figure 9 This is the present invention. Figure 5 Enlarged view of region A in the middle;

[0034] Figure 10 This is a side sectional view of the linkage sleeve in a washing tank according to an embodiment of the present invention;

[0035] Figure 11 This is an end connection diagram of the tilting assembly in a washing tank according to an embodiment of the present invention;

[0036] As shown in the figure: 1. Washing tank; 2. Drive mechanism; 3. Rinsing assembly; 4. Tilting assembly; 5. Discharge port; 6. First magnetic suction plate; 7. Motor; 8. Transmission box; 9. Drive shaft; 10. Driving gear; 11. Driven gear; 12. Driven shaft; 13. Lead screw; 14. First linkage sleeve; 15. Guide rod; 16. Threaded sleeve; 17. Flow guide box; 18. Water injection pipe; 19. Flow guide assembly; 20. 21. Second linkage sleeve; 22. Storage jacket; 23. Second magnetic suction plate; 24. Filter membrane; 25. Split clamping plate; 26. Partition plate; 27. Guide plate; 28. End plate; 29. ​​Inner layer opening; 30. Outer layer opening; 31. Limiting baffle; 32. Third magnetic suction plate; 33. Telescopic groove; 34. Spring rod; 35. Ball bearing; 36. Roller; 37. Connecting hole; 38. Winding box; 39. Gap; 30. Partition mesh. Detailed Implementation

[0037] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the invention, and should not be construed as limiting the invention. Rather, embodiments of the invention include all variations, modifications, and equivalents falling within the spirit and scope of the appended claims.

[0038] like Figures 1 to 11 As shown, the present invention provides the following embodiments:

[0039] Example 1

[0040] The lithium-based pentaerythritol production method includes the following steps: (1) Formaldehyde, acetaldehyde and lithium hydroxide are condensed in a molar ratio of 7:1:1.2 at a reaction temperature of 40°C for 1 hour and kept warm for 0.5 hours, and formic acid is added to neutralize to pH 6.5; (2) Excess formaldehyde in the material is removed by distillation; (3) Concentration is carried out and then cooled and crystallized for 6 hours; (4) Centrifugation, washing and drying are carried out to obtain pentaerythritol with a mass content of 98.3% and a yield of more than 96%; (5) The mother liquor obtained by centrifugation is precipitated, filtered and returned to be mixed with the dealdehyde liquid for recycling; (6) The filtrate is concentrated, crystallized, centrifuged, washed and dried to obtain lithium formate with a mass content of 98.3%.

[0041] Example 2

[0042] The lithium-based pentaerythritol production method includes the following steps: (1) Formaldehyde, acetaldehyde and lithium hydroxide are condensed in a molar ratio of 8:1:1.1 at a reaction temperature of 50°C for 1 hour and then kept warm for 0.5 hours. Formic acid is added to neutralize to pH 6.5; (2) Excess formaldehyde is removed from the material by distillation; (3) The material is concentrated and then cooled and crystallized for 6 hours; (4) The material is centrifuged, washed and dried to obtain pentaerythritol with a mass content of 98.6% and a yield of more than 96%; (5) The mother liquor obtained by centrifugation is precipitated, filtered and returned to be mixed with the dealdehyde liquid for recycling; (6) The filtrate is concentrated, crystallized, centrifuged, washed and dried to obtain lithium formate with a mass content of 98.5%.

[0043] The method provided in the above embodiments has no equipment blockage, high yield, reaction conversion rate of pentaerythritol series products reaches over 98%, and total yield reaches 96%; product quality is excellent (purity ≥98.0%); by-product lithium formate has a purity greater than 98%, high added value, and good overall economic efficiency of the production process; the mother liquor is completely recycled in a closed loop, with no pollution and is environmentally friendly.

[0044] Example 3

[0045] This embodiment also provides a washing tank 1 for use. The washing tank 1 includes: a drive mechanism 2, a rinsing assembly 3 and a tilting assembly 4. The bottom of the washing tank 1 is provided with a discharge port 5. The top two sides of the washing tank 1 are provided with first magnetic suction plates 6. The top middle area of ​​the washing tank 1 is integrally formed with a vertical plate, and the drive mechanism 2 is inserted in the middle of the vertical plate. The front end of the drive mechanism 2 is welded with a transmission box 8, and the front end of the transmission box 8 is screwed with a motor 7.

[0046] A rinsing assembly 3 is provided on the side of the driving mechanism 2, and a flipping assembly 4 is provided below the rinsing assembly 3. The flipping assembly 4 is used to store the precipitated crystals. A water injection pipe 18 is connected to the end of the rinsing assembly 3. The water injection pipe 18 is used to transport pure water into the interior of the rinsing assembly 3. The rinsing assembly 3 is used to guide the pure water towards the flipping assembly 4 below and spray it out.

[0047] Specifically, when using the washing tank 1, the precipitated crystals are placed inside the tilting component 4, and pure water is transported to the rinsing component 3 via the water injection pipe 18. The front drive mechanism 2 is activated, and the tilting component 4 is rotated to one side of the washing tank 1 by the drive mechanism 2. During this process, the drive mechanism 2 can synchronously control the top rinsing component 3 to rotate in the opposite direction through the internal gear structure, and cause the rinsing component 3 to rotate to the same position as the tilting component 4. At this time, the drive mechanism 2 is continued to run, and external pure water is transported to the rinsing component 3, so that the washing process of the material inside the tilting component 4 can be realized by the rinsing component 3. After the washing of one side is completed, the motor 7 in the drive mechanism 2 is controlled in the opposite direction, so that the tilting component 4 and the rinsing component 3 rotate to the other side at the same time, and the above process can be repeated until all the material inside is washed. After the washing is completed, the motor 7 is controlled to accelerate the swing, so that the tilting component 4 can be opened by the centrifugal effect, and the washed material inside can be discharged.

[0048] In this embodiment, the drive mechanism 2 includes: a drive shaft 9, a driven shaft 12, a drive gear 10, and a driven gear 11. The output end of the motor 7 is connected to the drive shaft 9. The drive gear 10 is connected to the surface of the drive shaft 9 by a key. Both ends of the driven shaft 12 are movably connected to the surface of the vertical plate at the top of the washing tank 1. A bearing is sleeved on the end of the driven shaft 12. The driven gear 11 is connected to the surface of the driven shaft 12 by a key. The drive gear 10 and the driven gear 11 mesh with each other.

[0049] Both the driving gear 10 and the driven gear 11 are hidden inside the transmission box 8, and the lead screw 13 is integrally formed on the driven shaft 12.

[0050] The drive mechanism 2 includes: a first linkage sleeve 14, a second linkage sleeve 20 and a threaded sleeve 16. The threaded sleeve 16 is sleeved on the surface of the lead screw 13. The side of the threaded sleeve 16 is partially welded to the flushing assembly 3. The side of the flipping assembly 4 is welded to the second linkage sleeve 20. The surface of the driven shaft 12 is also sleeved with the first linkage sleeve 14.

[0051] The first linkage sleeve 14 has a guide rod 15 welded to its side, and there are two first linkage sleeves 14. The two ends of the guide rod 15 are welded and fixed to different first linkage sleeves 14 respectively. The driven shaft 12 is used to control the rotation of the lead screw 13 and the first linkage sleeve 14. The drive shaft 9 is used to control the rotation of the second linkage sleeve 20.

[0052] The drive mechanism 2 further includes: a telescopic groove 32, a spring rod 33, and a ball bearing 34. The surfaces of the drive shaft 9 and the driven shaft 12 are both provided with telescopic grooves 32. The spring rod 33 is inserted into the inside of each telescopic groove 32. The ends of each spring rod 33 are welded with balls bearing 34. The inner walls of the first linkage sleeve 14 and the second linkage sleeve 20 are both provided with grooves. The balls bearing 34 are used to be embedded in the grooves and are also used to roll along the inner wall of the first linkage sleeve 14 or the second linkage sleeve 20.

[0053] During discharge, the pentaerythritol crystal material stored inside the flipping component 4 is accelerated and thrown towards the bottom by increasing the swing speed of the drive mechanism 2 through centrifugal effect, so that the material can be discharged more thoroughly inside the flat flipping component 4. This process can also be completed automatically, and the rinsing water utilization rate is higher, reducing the amount wasted from overflowing from the top.

[0054] Specifically, after starting the motor 7, the motor 7 can drive the drive shaft 9 to rotate. The drive shaft 9 drives the surface drive gear 10 to rotate. The drive gear 10, in conjunction with the driven gear 11, can directly drive the driven shaft 12 at the top to rotate in the opposite direction. At this time, the drive shaft 9, in conjunction with the surface second linkage sleeve 20, can drive the flipping component 4 to swing. The driven shaft 12, in turn, can drive the rinsing component 3 to swing from the top of the washing tank 1 through the first linkage sleeve 14.

[0055] During the transmission process between the drive shaft 9 and the driven shaft 12 and the second linkage sleeve 20 and the first linkage sleeve 14 respectively, the spring rod 33 on the drive shaft 9 or the driven shaft 12 will embed the end ball 34 into the groove on the inner wall of the first linkage sleeve 14 or the second linkage sleeve 20. With the help of the ball 34 and the groove, the first linkage sleeve 14 or the second linkage sleeve 20 can be directly driven to rotate until the flipping component 4 is pressed against the first magnetic plate 6 and is attracted and fixed. At this time, if the drive shaft 9 is continued to rotate, it will be impossible to continue to press the ball 34 against the spring rod 33. The second linkage sleeve 20 is driven to rotate, so the ball 34 will pass through the inside of each groove. However, the drive shaft 9 continues to rotate, so the driven shaft 12 and the lead screw 13 on the driven shaft 12 can also continue to rotate. However, the first linkage sleeve 14 cannot rotate because the limiting baffle 30 at the end of the rinsing assembly 3 has been pressed against the top of the first magnetic suction plate 6. As a result, the subsequent movement of the drive mechanism 2 can only drive the threaded sleeve 16 to move along the lead screw 13, that is, drive the rinsing assembly 3 to move on the surface of the flipping assembly 4.

[0056] In this embodiment, the flushing assembly 3 includes: a flow guide box 17, a water injection pipe 18, and a flow guide component 19. One end of the flow guide box 17 is welded and fixed to the drive mechanism 2. One end of the flow guide box 17 is connected to the water injection pipe 18. A limit baffle 30 is also welded to the end of the flow guide box 17. The flow guide component 19 is embedded inside the flow guide box 17. The limit baffle 30 is used to abut against the outside of the first magnetic suction plate 6.

[0057] The flow guiding assembly 19 includes: a flow guiding plate 26, an end plate 27, and an inner opening 28. A partition 25 is welded inside the flow guiding box 17. There are two flow guiding plates 26, and the same end of the two flow guiding plates 26 is integrally formed with an end plate 27. The surface of the end plate 27 is provided with an inner opening 28. There is a gap between the end of the partition 25 and the inner wall of the flow guiding box 17, and the partition 25 abuts against the inner wall of the end plate 27. The end of the flow guiding box 17 is provided with an outer opening 29. The inner opening 28 is used to align with the outer opening 29. The surface of each flow guiding plate 26 is provided with holes.

[0058] Specifically, in the flow guide box 17, as the flushing assembly 3 swings as a whole, the flow guide box 17 is attracted and attached to the second magnetic suction plate 22 on the flipping assembly 4. At this time, the flow guide plate 26 part of the inner flow guide assembly 19 located below will be affected by its own gravity and the attraction effect of the second magnetic suction plate 22 and move downward. Finally, the bottom flow guide plate 26 and the second magnetic suction plate 22 will be attracted and attached. During this process, the end plate 27 part of the end will move downward. Therefore, the inner opening 28 will be aligned with the lower area of ​​the outer opening 29. The cavity above the partition 25 will be blocked by the end plate 27, so the outer opening 29 cannot communicate with the upper cavity of the partition 25. Therefore, in this state, the injected pure water can only enter the cavity below the partition 25, ensuring that it passes through the holes on the lower flow guide plate 26 and enters the lower flipping assembly 4.

[0059] In this embodiment, the flipping assembly 4 includes: a storage interlayer 21, a winding box 37, a gap 38, a mesh 39, a split clamping plate 24, and a third magnetic suction plate 31. The storage interlayer 21 is provided with winding boxes 37 at both ends, and a gap 38 is provided at the top of the winding box 37. The top and bottom surfaces of the storage interlayer 21 are provided with mesh 39. The split clamping plate 24 is hinged to the end of the storage interlayer 21. A third magnetic suction plate 31 is installed at the end of the inner wall of the storage interlayer 21. The third magnetic suction plate 31 is used to adsorb and adhere to the inner side of the split clamping plate 24. The first magnetic suction plate 6 is used to adsorb and fix the end of the storage interlayer 21.

[0060] The flipping assembly 4 further includes: a second magnetic suction plate 22, a roller 35, and a filter membrane 23. Both ends of the second magnetic suction plate 22 are connected to the filter membrane 23. The filter membrane 23 is wound around the surface of the roller 35. The roller 35 is embedded in the inside of the winding box 37. The second magnetic suction plate 22 is pressed and adsorbed onto the surface of the storage interlayer 21. The surface of the second magnetic suction plate 22 is provided with a docking hole 36. The second magnetic suction plate 22 is also used to adsorb and dock with the flow guiding assembly 19.

[0061] The semi-open washing tank 1, with the help of the flipping component 4, washes the pentaerythritol crystal material to be washed. In conjunction with the drive mechanism 2 and the washing component 3, the material in a flat state can be washed on both sides, which makes the washing efficiency stronger and more efficient. It can avoid the washing dead corners caused by thickness issues. Moreover, the flipping process is highly automated, and only a single power device is needed to complete the flipping, washing and discharge processes.

[0062] Specifically, after the entire flipping assembly 4 is driven to rotate by the drive mechanism 2, it eventually docks with the second magnetic suction plate 22 as the rinsing assembly 3 moves. At this time, the guide box 17 moves horizontally, which will synchronously change the position of the second magnetic suction plate 22, thereby changing the range of water spray washing on the storage jacket 21. As the guide box 17 moves, the material in any area of ​​the storage jacket 21 can be washed. The washing water directly passes over the top filter membrane 23 and passes through the upper mesh 39 and the bottom filter membrane 23 in sequence to realize the rinsing process of the crystallized material.

[0063] After washing the materials on both sides of the storage jacket 21, the motor 7 can be controlled to accelerate the swing. With the help of centrifugal effect, the split clamp 24 at the end of the storage jacket 21 can be pushed open. Through the centrifugal action of accelerated swing, the washed materials inside are thrown downwards and finally discharged from the discharge port 5 below.

[0064] The terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance. Furthermore, in the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0065] Any process or method description in the flowchart or otherwise herein can be understood as representing a module, segment, or portion of code comprising one or more executable instructions for implementing a particular logical function or process, and the scope of the preferred embodiments of the invention includes additional implementations in which functions may be performed not in the order shown or discussed, including substantially simultaneously or in reverse order depending on the functions involved, as will be understood by those skilled in the art to which embodiments of the invention pertain.

[0066] In the description of this specification, references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0067] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A novel method for producing pentaerythritol, characterized in that, Includes the following steps: S1. Mix formaldehyde, acetaldehyde and lithium hydroxide in the specified proportions and carry out a condensation reaction. After the reaction, add formic acid to neutralize the solution. S2. Collect the neutralized solution and perform distillation to remove excess formaldehyde from the material; S3. After removing excess formaldehyde, concentrate the solution and then cool it down until crystals precipitate. S4. The precipitated crystals are centrifuged and then placed into a washing tank. The washing tank is equipped with a tilting component to store the precipitated crystals. Pure water is injected into the rinsing component at the top of the washing tank. Both the tilting component and the rinsing component are controlled by a drive mechanism. The drive mechanism controls the rinsing component to move along the tilting component to wash the precipitated crystals. After washing is completed, the drive mechanism is controlled to drive the flipping component to swing rapidly, unfolding the split clamps at the end of the flipping component, and throwing the washed crystallized material inside the flipping component downwards. Then the washed material is collected and dried to obtain pentaerythritol product. S5. The crystals precipitated in step S3 are centrifuged and then the mother liquor obtained is used to precipitate them. The mother liquor is then filtered and the filtered solution is rinsed and refluxed and mixed with the formaldehyde removal solution for recycling. S6. Finally, the remaining filtrate is concentrated, crystallized, centrifuged, washed, and dried to obtain lithium formate.

2. The novel production method of pentaerythritol according to claim 1, characterized in that, In step S1, the molar ratio of formaldehyde, acetaldehyde, and lithium hydroxide is 6-10:1:1-1.5, the reaction temperature is 30-55℃, the reaction time is 1-2 hours, and the temperature is maintained for 0.5-1 hour. After the condensation reaction, formic acid is added until the pH of the solution is adjusted to 5.5-7.5; In step S3, the cooling time ranges from 3 to 6 hours.

3. The novel production method of pentaerythritol according to claim 1, characterized in that, The washing tank used in step S4 includes: The washing tank includes a drive mechanism, a rinsing assembly, and a tilting assembly. The bottom of the washing tank has a discharge port, and the top of the washing tank has two first magnetic suction plates on both sides. The top middle area of ​​the washing tank has an integrally formed upright plate, and the drive mechanism is inserted in the middle of the upright plate. The front end of the drive mechanism is welded with a transmission box, and the front end of the transmission box is screwed with a motor. A rinsing assembly is provided on the side of the driving mechanism, and a tilting assembly is provided below the rinsing assembly. The tilting assembly is used to store the precipitated crystals. A water injection pipe is connected to the end of the rinsing assembly. The water injection pipe is used to transport pure water into the interior of the rinsing assembly. The rinsing assembly is used to guide and spray the pure water toward the tilting assembly position below.

4. The novel production method of pentaerythritol according to claim 3, characterized in that, The drive mechanism includes: The motor comprises a drive shaft, a driven shaft, a drive gear, and a driven gear. The output end of the motor is connected to the drive shaft, and the drive gear is connected to the surface of the drive shaft by a key. Both ends of the driven shaft are movably connected to the surface of the vertical plate on the top of the washing tank, and a bearing is sleeved on the end of the driven shaft. The driven gear is connected to the surface of the driven shaft by a key, and the drive gear and the driven gear mesh. Both the driving gear and the driven gear are hidden inside the transmission box, and a lead screw is integrally formed on the driven shaft.

5. The novel production method of pentaerythritol according to claim 4, characterized in that, The drive mechanism includes: The system comprises a first linkage sleeve, a second linkage sleeve, and a threaded sleeve. The threaded sleeve is fitted onto the surface of the lead screw. The side of the threaded sleeve is welded to the flushing assembly. The side of the flipping assembly is welded to the second linkage sleeve. The surface of the driven shaft is also fitted with the first linkage sleeve. The first linkage sleeve has a guide rod welded to its side, and there are two first linkage sleeves. The two ends of the guide rod are welded and fixed to different first linkage sleeves respectively. The driven shaft is used to control the rotation of the lead screw and the first linkage sleeve, and the drive shaft is used to control the rotation of the second linkage sleeve.

6. The novel production method of pentaerythritol according to claim 5, characterized in that, The drive mechanism also includes: The drive shaft and driven shaft are provided with telescopic grooves, spring rods and ball bearings. The surfaces of the drive shaft and driven shaft are provided with telescopic grooves, and spring rods are inserted into the inside of the telescopic grooves. Ball bearings are welded to the ends of the spring rods. The inner walls of the first linkage sleeve and the second linkage sleeve are provided with grooves. The ball bearings are used to be embedded in the grooves and are also used to roll along the inner wall of the first linkage sleeve or the second linkage sleeve.

7. The novel production method of pentaerythritol according to claim 4, characterized in that, The flushing assembly includes: The flow guide box, water injection pipe, and flow guide assembly are provided. One end of the flow guide box is welded and fixed to the drive mechanism. One end of the flow guide box is connected to the water injection pipe. A limit baffle is also welded to the end of the flow guide box. The flow guide assembly is embedded inside the flow guide box. The limit baffle is used to abut against the outside of the first magnetic suction plate.

8. The novel production method of pentaerythritol according to claim 7, characterized in that, The flow guiding component includes: The flow guide plate, end plate, and inner layer opening are provided. The flow guide box has a partition welded inside. There are two flow guide plates, and the same end of the two flow guide plates is integrally formed with an end plate. The surface of the end plate is provided with an inner layer opening. There is a gap between the end of the partition and the inner wall of the flow guide box, and the partition rests against the inner wall of the end plate. The end of the flow guide box has an outer opening, and the inner opening is used to align with the outer opening. Each flow guide plate has holes on its surface.

9. The novel production method of pentaerythritol according to claim 7, characterized in that, The flipping component includes: The storage interlayer comprises a winding box, a gap, a mesh, a split clamping plate, and a third magnetic plate. The winding box is provided at both ends of the storage interlayer, and a gap is provided at the top of the winding box. The top and bottom surfaces of the storage interlayer are provided with mesh. The split clamping plate is hinged to the end of the storage interlayer. A third magnetic plate is installed at the end of the inner wall of the storage interlayer. The third magnetic plate is used to adhere to the inner side of the split clamping plate. The first magnetic plate is used to fix the end of the storage interlayer by adsorption.

10. The novel production method of pentaerythritol according to claim 9, characterized in that, The flipping component also includes: The second magnetic plate, the roller, and the filter membrane are all connected to the two ends of the second magnetic plate. The filter membrane is wound on the surface of the roller. The roller is embedded in the inside of the winding box. The second magnetic plate is pressed and adsorbed on the surface of the storage interlayer. The surface of the second magnetic plate is provided with docking holes. The second magnetic plate is also used to adsorb and dock with the flow guiding component.

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