A high-yield continuous production device and process for mono- and di-pentaerythritol

Abstract

The present application relates to the technical field of cooling separation, and particularly relates to a high-yield continuous production device and process of mono- and di-pentaerythritol, and the high-yield continuous production device of mono- and di-pentaerythritol comprises a crystallization cylinder, a cooling tower and a liquid outlet mechanism; the liquid inlet end of the crystallization cylinder and the cooling tower is communicated through a first pipeline, the upper end of the crystallization cylinder is provided with a feed inlet, and a concentration sensor is arranged at the feed inlet; the liquid outlet mechanism comprises a liquid outlet pipe group and an adjusting unit, the liquid outlet pipe group is located in the crystallization cylinder and is communicated with the first pipeline. The solution entering the crystallization cylinder will first flow out from the liquid outlet pipe group, the liquid outlet pipe group is heated, the solution entering the liquid outlet pipe group or the solution near the liquid outlet pipe group is heated, the crystals carried by the solution near the liquid outlet pipe group are dissolved again, and the amount of the crystals flowing out through the liquid outlet pipe group is greatly reduced. The adjusting unit adjusts the position of the liquid outlet pipe group according to the solution concentration at the feed inlet detected by the concentration sensor, and reduces the adhesion of the crystals outside the liquid outlet pipe group.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of cooling separation, in particular to a high-yield continuous production device and process for mono- and di-pentaerythritol. BACKGROUND

[0002] Pentaerythritol and its homologues (such as mono- and di-pentaerythritol) are an important class of polyols, which have a wide range of applications in the synthesis of resins, coatings, lubricating oils, explosives, and plastics. In traditional batch or early continuous production processes, the separation and purification of the mixed solution containing mono- and di-pentaerythritol obtained from the reaction section is a key step, which directly affects the yield, purity and economic benefits of the final product. Crystallization, as an important means of separation and purification, is widely used in this process. The typical process is to cool the saturated solution at high temperature, take advantage of the property that the solubility of the target product in the solvent decreases with decreasing temperature, and make it precipitate in the form of crystals, and then separate the crystals from the liquid.

[0003] However, the existing continuous crystallization device for mono- and di-pentaerythritol production generally has problems such as efficiency reduction due to cooling system fouling, unstable operation due to crystal loss or local blockage, and insufficient adaptability to changes in feed conditions. These problems ultimately lead to difficulty in further improving product yield, increased production costs, and shortened device operation period. It is urgent to develop a continuous production device and technical solution that can intelligently adapt to changes in feed, effectively prevent crystal loss and cooling system fouling, and thus achieve high-yield stable operation. SUMMARY

[0004] The present application provides a high-yield continuous production device and process for mono- and di-pentaerythritol to solve the problem of cooling system fouling caused by easy loss of crystals in the crystallization process of mono- and di-pentaerythritol production in the prior art.

[0005] The high-yield continuous production device and process for mono- and di-pentaerythritol of the present application adopts the following technical solution:

[0006] A high-yield continuous production apparatus for mono- and dipentaerythritol includes a crystallization cylinder, a cooling tower, and a liquid discharge mechanism. The inlet of the crystallization cylinder and the cooling tower are connected via a first pipeline, and the outlet of the crystallization cylinder and the cooling tower are connected via a second pipeline. The second pipeline extends into the crystallization cylinder, and its outlet is located below the position where the first pipeline connects to the crystallization cylinder. A feed inlet is provided at the upper end of the crystallization cylinder, and a concentration sensor is installed at the feed inlet. The liquid discharge mechanism includes a liquid discharge pipe assembly and an adjustment unit. The liquid discharge pipe assembly is located below the liquid surface in the crystallization cylinder and above the outlet of the second pipeline, and is connected to the first pipeline. The lower end of the liquid discharge pipe assembly is connected to the solution inside the crystallization cylinder, and a filter screen is provided at the connection point. The vertical position of the liquid discharge pipe assembly within the crystallization cylinder is adjustable. The adjustment unit adjusts the position of the liquid discharge pipe assembly according to the solution concentration at the feed inlet detected by the concentration sensor, and the distance between the liquid discharge pipe assembly and the liquid surface in the crystallization cylinder is positively correlated with the solution concentration at the feed inlet.

[0007] Optionally, the adjustment unit includes a float ring, a connecting cylinder, and a driving component; the connecting cylinder is slidably sleeved outside the second pipeline and its rotation is restricted by the second pipeline; the liquid outlet pipe assembly is fixedly connected to the connecting cylinder; the float ring is located above the liquid outlet pipe assembly and is threadedly connected to the connecting cylinder, and the float ring is located above the liquid surface inside the crystallization cylinder under the action of buoyancy and drives the liquid outlet pipe assembly to move up and down synchronously; the driving component is used to drive the float ring to rotate, thereby causing the connecting cylinder to drive the liquid outlet pipe assembly to move up and down; the driving component and the concentration sensor are linked through a program to determine the direction and angle of its driving the float ring to rotate.

[0008] Optionally, the outlet pipe assembly is connected to the first pipeline via a flexible hose.

[0009] Optionally, a high-yield continuous production apparatus for mono- and dipentaerythritol also includes a suction pump, which is installed in the first pipeline to promote the circulation of the solution between the crystallization cylinder and the cooling tower.

[0010] Optionally, the liquid outlet pipe assembly includes a ring section and a straight section. The ring section is horizontally arranged and connected to the first pipeline, while the straight section is vertically or inclined and located below the ring section and connected to the interior of the ring section. The filter screen is located at the lower end of the straight section.

[0011] Optionally, multiple straight cylindrical sections are provided, which are distributed circumferentially around the annular sections; multiple annular sections are provided, which are nested inside and outside and are internally connected.

[0012] Optionally, the float ring is threadedly engaged with the connecting cylinder via a mounting bracket, the float ring is fixed to the mounting bracket, and the mounting bracket is threadedly engaged with the connecting cylinder; the driving component includes a motor, a drive shaft, a drive sleeve, and a first drive wheel, the first drive wheel is disposed on the mounting bracket and can drive the mounting bracket to rotate synchronously and move up and down synchronously with the mounting bracket; the drive shaft extends into the crystallizing cylinder and rotates under the drive of the motor disposed outside the crystallizing cylinder; the drive sleeve is slidably sleeved on the outside of the drive shaft and engages with the drive shaft via a spline; a second drive wheel is disposed outside the drive sleeve and engages with the first drive wheel.

[0013] Optionally, the bottom of the crystallization cylinder is funnel-shaped, wider at the top and narrower at the bottom.

[0014] Optionally, a discharge port is provided at the bottom of the crystallization cylinder.

[0015] A high-yield continuous production process for mono- and dipentaerythritol, utilizing the aforementioned high-yield continuous production apparatus for mono- and dipentaerythritol, includes the following steps:

[0016] S10, continuously feeds solution into the crystallizing cylinder through the feed inlet; the adjusting unit adaptively adjusts the height of the liquid outlet pipe assembly;

[0017] S20, the solution enters the first pipeline through the liquid outlet pipe group and then enters the cooling tower for cooling. After that, it returns to the bottom of the crystallization cylinder through the second pipeline and crystallizes and settles at the bottom of the crystallization cylinder.

[0018] The beneficial effects of this invention are as follows: The high-yield continuous production apparatus for mono- and dipentaerythritols of this invention uses a filter screen at the lower end of the outlet pipe assembly to intercept and prevent crystals from flowing out. Furthermore, the outlet pipe assembly is located inside the crystallization cylinder, below the feed inlet at the upper end of the cylinder. The solution entering the crystallization cylinder first flows past the outlet pipe assembly, heating it. This causes the solution entering or near the outlet pipe assembly to heat up, dissolving any crystals carried by the nearby solution, thus significantly reducing the amount of crystals flowing out through the outlet pipe assembly.

[0019] Furthermore, by incorporating an adjustment unit, when the solution concentration at the inlet is high, the distance between the outlet pipe assembly and the liquid surface inside the crystallizing cylinder is increased. This causes the outlet pipe assembly to move downwards, allowing the newly entering solution to crystallize above the outlet pipe assembly, reducing crystal adhesion outside the assembly. When the solution concentration at the inlet is low, the outlet pipe assembly can be moved slightly upwards, closer to the newly entering solution. This allows the newly entering solution to appropriately heat the area near the outlet pipe assembly, reducing the amount of crystals flowing out with the assembly and thus reducing scaling in the cooling tower. Attached Figure Description

[0020] 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.

[0021] Figure 1 This is a schematic diagram of the overall structure of an embodiment of the high-yield continuous production apparatus for mono- and dipentaerythritols of the present invention.

[0022] Figure 2This is a front view of the overall structure of an embodiment of the high-yield continuous production apparatus for mono- and dipentaerythritol of the present invention;

[0023] Figure 3 This is a side view of the overall structure of an embodiment of the high-yield continuous production apparatus for mono- and dipentaerythritol of the present invention;

[0024] Figure 4 for Figure 3 Schematic diagram of cross section along the AA direction;

[0025] Figure 5 for Figure 4 Enlarged view of point X in the middle;

[0026] Figure 6 for Figure 4 Another perspective illustration;

[0027] Figure 7 for Figure 6 Enlarged view of point Y in the middle;

[0028] Figure 8 This is a schematic diagram of the outlet pipe assembly, float ring, and mounting frame in an embodiment of the high-yield continuous production apparatus for mono- and dipentaerythritol of the present invention.

[0029] In the diagram: 100, crystallization cylinder; 110, first pipeline; 120, second pipeline; 130, feed inlet; 140, concentration sensor; 150, discharge outlet; 200, cooling tower; 300, suction pump; 400, liquid discharge mechanism; 410, liquid discharge pipe assembly; 411, filter screen; 412, ring section; 413, straight cylinder section; 420, floating ring; 421, mounting bracket; 430, connecting cylinder; 440, driving component; 441, motor; 442, drive shaft; 443, drive sleeve; 444, first drive wheel; 445, second drive wheel. Detailed Implementation

[0030] 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, and 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.

[0031] An embodiment of a high-yield continuous production apparatus for mono- and dipentaerythritol according to the present invention, such as... Figures 1 to 8 As shown, it includes a crystallization cylinder 100, a cooling tower 200, and a liquid outlet mechanism 400.

[0032] The inlet of the crystallizing cylinder 100 is connected to the liquid inlet of the cooling tower 200 via a first pipe 110, and the outlet of the cooling tower 200 is connected via a second pipe 120. The second pipe 120 extends into the crystallizing cylinder 100, and its outlet is located below the position where the first pipe 110 connects to the crystallizing cylinder 100. The cooling tower 200 is a heat exchange device in the prior art, and its interior is provided with mutually isolated coolant channels and solution channels.

[0033] A feed inlet 130 is provided at the upper end of the crystallization cylinder 100, and a concentration sensor 140 is provided at the feed inlet 130. The feed inlet 130 is used to receive a solution containing mono- and dipentaerythritol obtained from the previous process (not shown in the figure), and the solution has a high temperature. The concentration sensor 140 is used to detect the concentration of the solution at the feed inlet 130, and then determine the amount of mono- and dipentaerythritol in the solution.

[0034] The liquid outlet mechanism 400 includes an outlet pipe assembly 410 and an adjustment unit. The outlet pipe assembly 410 is located below the liquid surface inside the crystallization cylinder 100 and above the outlet of the second pipe 120, and is connected to the first pipe 110. The lower end of the outlet pipe assembly 410 is connected to the solution inside the crystallization cylinder 100, and a filter screen 411 is provided at the connection point. The vertical position of the outlet pipe assembly 410 inside the crystallization cylinder 100 is adjustable. The adjustment unit adjusts the position of the outlet pipe assembly 410 according to the solution concentration at the feed inlet 130 detected by the concentration sensor 140, and makes the distance between the outlet pipe assembly 410 and the solution concentration at the feed inlet 130 positively correlated with the distance between the liquid surface inside the crystallization cylinder 100 and the liquid surface.

[0035] During normal operation, the solution enters the crystallizing cylinder 100 through the inlet 130, passes through the outlet pipe assembly 410, and then enters the first pipe 110. After being cooled by the cooling tower 200, it returns to the bottom of the crystallizing cylinder 100 along the second pipe 120. As the solution cools, the temperature decreases, causing the mono- and dipentaerythritols in the solution to precipitate and form crystals. The continuously flowing solution circulates between the crystallizing cylinder 100 and the cooling tower 200, continuously lowering the temperature of the solution in the crystallizing cylinder 100 and promoting crystal precipitation. When the solution enters the first pipe 110 through the outlet pipe assembly 410, some crystals may not have time to settle and flow out with the solution. These crystals may adhere to the cooling tower 200 upon entering, affecting its cooling efficiency. A filter screen 411 is installed to intercept these crystals and prevent them from flowing out. Furthermore, the liquid outlet pipe assembly 410 is located inside the crystallization cylinder 100, below the feed inlet 130 located at the upper end of the crystallization cylinder 100. The solution entering the crystallization cylinder 100 is usually at a high temperature. When it flows out of the liquid outlet pipe assembly 410, it will heat up the liquid outlet pipe assembly 410, causing the solution entering or near the liquid outlet pipe assembly 410 to heat up, causing the crystals carried by the nearby solution to dissolve again, greatly reducing the amount of crystals flowing out through the liquid outlet pipe assembly 410.

[0036] Furthermore, the higher the concentration of the solution entering through inlet 130, the easier it is for crystals to precipitate when encountering the solution that has already been circulated and cooled within the crystallizing cylinder 100. This crystals tend to adhere to the outside of the outlet pipe assembly 410, affecting the heat exchange efficiency at the outlet pipe assembly 410. By setting up an adjustment unit, when the solution concentration at inlet 130 is high, the distance between the outlet pipe assembly 410 and the liquid surface inside the crystallizing cylinder 100 is increased. That is, the outlet pipe assembly 410 is moved downwards, allowing the newly entering solution to crystallize above the outlet pipe assembly 410, reducing crystal adhesion to the outside of the outlet pipe assembly 410. When the solution concentration at inlet 130 is low, the outlet pipe assembly 410 can be moved upwards appropriately, closer to the newly entering solution. This allows the newly entering solution to appropriately heat the area around the outlet pipe assembly 410, reducing the amount of crystals flowing out with the outlet pipe assembly 410, thereby reducing the amount of scaling in the cooling tower 200.

[0037] In this embodiment, the adjustment unit includes a float ring 420, a connecting cylinder 430, and a driving component 440. The connecting cylinder 430 is slidably sleeved outside the second pipe 120 and its rotation is restricted by the second pipe 120. The liquid outlet pipe assembly 410 is fixedly connected to the connecting cylinder 430. The float ring 420 is located above the liquid outlet pipe assembly 410 and is threadedly connected to the connecting cylinder 430. Under the action of buoyancy, the float ring 420 is located above the liquid surface inside the crystallization cylinder 100 and drives the liquid outlet pipe assembly 410 to move up and down synchronously. The driving component 440 is used to drive the float ring 420 to rotate, thereby causing the connecting cylinder 430 to drive the liquid outlet pipe assembly 410 to move up and down. The driving component 440 is linked with the concentration sensor 140 through a program to determine the direction and angle of its driving the float ring 420 to rotate. A convex ring (not shown in the figure) may be provided outside the second pipe 120 to limit the downward movement limit of the connecting cylinder 430. A float ring 420, which rises and falls with the liquid level, synchronously moves the outlet pipe assembly 410 up and down, ensuring that the outlet pipe assembly 410 is always below the liquid level. The drive unit 440 activates when the concentration value detected by the concentration sensor 140 is greater than or less than a preset range. When the concentration is greater than the preset range, the drive unit 440 drives the float ring 420 to rotate clockwise, causing the connecting cylinder 430 to move the outlet pipe assembly 410 downwards. When the concentration is less than the preset range, the drive unit 440 drives the float ring 420 to rotate counterclockwise, causing the connecting cylinder 430 to move the outlet pipe assembly 410 upwards. The preset range can be set according to the actual concentration of the solution.

[0038] In this embodiment, the liquid outlet pipe assembly 410 is connected to the first pipeline 110 via a flexible hose to avoid interfering with the vertical movement of the liquid outlet pipe assembly 410. In some other embodiments, the liquid outlet pipe assembly 410 may also be connected to the first pipeline 110 via a telescopic pipe.

[0039] In this embodiment, the high-yield continuous production apparatus for mono- and dipentaerythritol also includes a suction pump 300, which is installed in the first pipeline 110 to promote the circulation of the solution between the crystallization cylinder 100 and the cooling tower 200.

[0040] In this embodiment, the liquid outlet pipe assembly 410 includes a ring section 412 and a straight section 413. The ring section 412 is horizontally arranged and communicates with the first pipe 110. The straight section 413 is vertically or inclinedly arranged and located below the ring section 412 and communicates with the interior of the ring section 412. The filter screen 411 is arranged at the lower end of the straight section 413. The straight section 413 is vertically arranged. As the crystals attached to the filter screen 411 increase, they will settle under the action of gravity. When the liquid level in the crystallization cylinder 100 drops to below the straight section 413, the liquid in the straight section 413 flows back into the crystallization cylinder 100, which can backflush the filter screen 411 and further promote the crystals attached to the filter screen 411 to fall off.

[0041] In this embodiment, there are multiple straight cylindrical sections 413, which are distributed circumferentially around the annular section 412; there are multiple annular sections 412, which are nested inside and out and are internally connected.

[0042] In this embodiment, the float ring 420 is threadedly engaged with the connecting cylinder 430 via a mounting bracket 421. The float ring 420 is fixed to the mounting bracket 421, and the mounting bracket 421 is threadedly engaged with the connecting cylinder 430. The driving component 440 includes a motor 441, a drive shaft 442, a drive sleeve 443, and a first drive wheel 444. The first drive wheel 444 is disposed on the mounting bracket 421 and can drive the mounting bracket 421 to rotate synchronously and move up and down synchronously with the mounting bracket 421. The drive shaft 442 extends into the crystallization cylinder 100 and rotates under the drive of the motor 441, which is disposed outside the crystallization cylinder 100. The drive sleeve 443 is slidably sleeved on the outside of the drive shaft 442 and is splinedly engaged with the drive shaft 442. A second drive wheel 445 is disposed outside the drive sleeve 443 and engages with the first drive wheel 444. Both the first drive wheel 444 and the second drive wheel 445 are gears or friction wheels.

[0043] In this embodiment, the bottom of the crystallization cylinder 100 is funnel-shaped, with a larger top and a smaller bottom.

[0044] In this embodiment, a discharge port 150 is provided at the bottom of the crystallization cylinder 100, and a valve (not shown in the figure) is installed at the discharge port 150 to control the opening or closing of the discharge port 150, thereby controlling the discharge of crystals.

[0045] In the high-yield continuous production apparatus for mono- and dipentaerythritol of the present invention, the solution enters the crystallization cylinder 100 through the feed inlet 130. The float ring 420 moves upward as the liquid level in the crystallization cylinder 100 rises, simultaneously driving the outlet pipe assembly 410 upward, ensuring that the outlet pipe assembly 410 remains below the liquid level. After the liquid level reaches a suitable height, while continuing to feed through the feed inlet 130, the suction pump 300 is activated, causing the solution in the crystallization cylinder 100 to pass through the outlet pipe assembly 410 and enter the first pipe 110. After being cooled by the cooling tower 200, it returns to the bottom of the crystallization cylinder 100 along the second pipe 120. The cooling process lowers the solution temperature, causing the mono- and dipentaerythritols in the solution to precipitate and form crystals. The continuously flowing solution circulates between the crystallization cylinder 100 and the cooling tower 200, continuously lowering the solution temperature in the crystallization cylinder 100 and promoting crystal precipitation.

[0046] The solution entering the crystallization cylinder 100 first flows out of the outlet pipe group 410, which heats the outlet pipe group 410. This causes the solution entering or near the outlet pipe group 410 to heat up, dissolving the crystals carried by the nearby solution and preventing the crystals from flowing out through the outlet pipe group 410.

[0047] The higher the concentration of the solution entering through inlet 130, the easier it is for crystals to precipitate when encountering the solution that has already been circulated and cooled within the crystallizing cylinder 100. This crystals then tend to adhere to the outside of the outlet pipe assembly 410, affecting the heat exchange efficiency at the outlet pipe assembly 410. When the solution concentration at inlet 130 is greater than a preset range, the drive unit 440 drives the float ring 420 to rotate forward, causing the connecting cylinder 430 to move the outlet pipe assembly 410 downwards. This allows the newly entering solution to crystallize above the outlet pipe assembly 410, reducing crystal adhesion to the outside of the outlet pipe assembly 410. When the solution concentration at inlet 130 is less than the preset range, the drive unit 440 drives the float ring 420 to rotate in reverse, causing the connecting cylinder 430 to move the outlet pipe assembly 410 upwards, closer to the newly entering solution. This allows the newly entering solution to appropriately heat the area around the outlet pipe assembly 410, reducing the amount of crystals flowing out with the outlet pipe assembly 410, thereby reducing the amount of scaling in the cooling tower 200.

[0048] A high-yield continuous production process for mono- and dipentaerythritol, utilizing the aforementioned high-yield continuous production apparatus for mono- and dipentaerythritol, includes the following steps:

[0049] S10, solution is continuously fed into crystallizing cylinder 100 through feed inlet 130; adjustment unit adaptively adjusts the height of liquid outlet pipe assembly 410;

[0050] S20, the solution enters the first pipeline 110 through the liquid outlet pipe group 410 and then enters the cooling tower 200 for cooling. After that, it returns to the bottom of the crystallizing cylinder 100 through the second pipeline 120 and crystallizes and settles at the bottom of the crystallizing cylinder 100.

[0051] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A continuous production apparatus of high yield of mono, di-pentaerythritol, characterized by, The crystallization cylinder, the cooling tower and the liquid outlet mechanism are included. The crystallization cylinder is communicated with the liquid inlet end of the cooling tower through a first pipeline and communicated with the liquid outlet end of the cooling tower through a second pipeline. The upper end of the crystallization cylinder is provided with a feeding port, and a concentration sensor is arranged at the feeding port. The liquid outlet mechanism includes a liquid outlet pipe group and an adjusting unit. The adjusting unit includes a floating ring, a connecting cylinder and a driving member.

2. A continuous production apparatus for high yield of mono, di-pentaerythritol according to claim 1, characterized in that, The liquid outlet pipe group is communicated with the first pipeline through a hose.

3. A continuous process for the production of mono and di-pentaerythritol in high yield as claimed in claim 1 wherein, A suction pump is arranged in the first pipeline to promote the circulation of the solution between the crystallization cylinder and the cooling tower.

4. A continuous process for the production of mono and di-pentaerythritol in high yield as claimed in claim 1 wherein, The liquid outlet pipe group includes a ring segment and a straight cylinder segment.

5. A continuous process for the high yield production of mono and di-pentaerythritol according to claim 4, wherein, The straight cylinder segment is provided with a plurality of segments and is distributed in a circumferential direction.

6. A continuous process for the high yield production of mono and di-pentaerythritol as claimed in claim 2 wherein, The floating ring is fixed to the mounting bracket and the mounting bracket is threadedly connected with the connecting cylinder.

7. A continuous process for the production of mono and di-pentaerythritol in high yield as claimed in claim 1 wherein, The bottom of the crystallization cylinder is funnel-shaped.

8. A continuous process for the production of mono and di-pentaerythritol in high yield as claimed in claim 1 wherein, The bottom of the crystallization cylinder is provided with a discharge port.

9. A continuous production process of high yield of mono- and di- ester of pentaerythritol using the continuous production apparatus of high yield of mono- and di- ester of pentaerythritol according to any one of claims 1 to 8, characterized in that, The following steps are included: S10, continuously feeding the solution into the crystallization cylinder through the feeding port; The adjusting unit adjusts the height of the liquid outlet pipe group adaptively; S20, the solution enters the first pipeline through the liquid outlet pipe group, is cooled in the cooling tower, and then returns to the bottom of the crystallization cylinder, and is crystallized and settled at the bottom of the crystallization cylinder.

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