Pentaerythritol large-particle crystallization device

Abstract

The utility model discloses a pentaerythritol large particle crystallization device, which comprises an evaporation separator, a crystallizer, a heater, a spiral conveyor and a circulating pump, a liquid outlet of the evaporation separator extends into the crystallizer, a first discharge pipe and a second discharge pipe are arranged at the bottom of the crystallizer, a third discharge pipe is arranged at the upper part of the crystallizer, and the second discharge pipe is arranged at the lower part of the crystallizer. One end of the circulating pump is communicated with the third discharging pipe, the other end of the circulating pump is communicated with the heater, the other end of the heater extends to the middle of the evaporation separator, the first discharging pipe is communicated with a feeding port of the spiral conveyor, and a discharging port of the spiral conveyor is communicated with the bottom of the evaporation separator. According to the utility model, secondary contact crystallization is carried out on crystal grains and a supersaturated solution, so that the granularity of the final formed grain size is improved.

Description

Technical Field

[0001] This utility model relates to the field of crystallization equipment technology, and in particular to a pentaerythritol large particle crystallization device. Background Technology

[0002] Pentaerythritol is a white crystalline powder at room temperature. It is mainly prepared by cooling and crystallizing the mother liquor. Although using a traditional Oslo cooling crystallizer can accelerate the crystallization speed and improve production efficiency, the solid particles produced directly are relatively small.

[0003] Patent 202020245424.5 discloses an Oslo cooling crystallizer, which extends the crystallization time and improves the final crystal particle size by setting an arc-shaped baffle inside the crystallizer. After the small crystal particles formed from the raw material feed pipe outlet pass through the arc-shaped baffle, they move upward along the tangent of the arc-shaped baffle port.

[0004] However, the crystallization particles in this technical solution have a low upward backflow height due to the obstruction of the arc-shaped baffle. Therefore, the upward backflow process results in a limited extension of the crystallization time, leading to very limited growth of the final crystal particles. Utility Model Content

[0005] The purpose of this invention is to overcome the shortcomings of the prior art and provide a pentaerythritol large particle crystallization device to solve the problem of low crystal particle size.

[0006] The objective of this utility model is achieved through the following technical solution: a pentaerythritol large particle crystallization device, comprising an evaporator separator, a crystallizer, a heater, a screw conveyor, and a circulating pump. The outlet of the evaporator separator extends into the crystallizer. A first discharge pipe and a second discharge pipe are provided at the bottom of the crystallizer, and a third discharge pipe is provided at the top of the crystallizer. One end of the circulating pump is connected to the third discharge pipe, and the other end of the circulating pump is connected to the heater. The other end of the heater extends to the middle of the evaporator separator. The first discharge pipe is connected to the inlet of the screw conveyor, and the outlet of the screw conveyor is connected to the bottom of the evaporator separator.

[0007] Furthermore, the crystallizer is provided with a first cylinder and a second cylinder, which are concentrically arranged with the crystallizer. Both the first cylinder and the second cylinder are open at both ends. The first cylinder is circumferentially sealed and fixedly connected to the upper and lower surfaces of the crystallizer. The first cylinder divides the crystallizer into an external separation chamber and an internal circulation chamber. The second cylinder is suspended and fixed in the circulation chamber. The lower part of the first cylinder is provided with a liquid passage hole.

[0008] Furthermore, a spiral propeller is provided inside the crystallizer, and the spiral propeller is located at the lower part of the second cylinder.

[0009] Furthermore, the propeller is positioned so that its pushing direction is upward.

[0010] Furthermore, the heater has a shell-and-tube heat exchanger structure.

[0011] Furthermore, a motor is provided on the crystallizer, the motor is located at the bottom center of the crystallizer, and the output end of the motor is connected to the propeller.

[0012] This invention has the following advantages: by installing a screw conveyor outside the crystallizer, the crystal grains that have been cooled and crystallized inside the crystallizer are transported to the evaporator separator through the first discharge pipe. The crystal grains preferentially contact the supersaturated solution formed in the evaporator separator, causing the crystals to precipitate again and coat the crystal grains. By coating the outer surface of the crystal grains multiple times, large-particle crystals can be produced, which solves the problem of the small average particle size of the crystal grains precipitated by the existing Oslo crystallizer. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of the overall structure of an embodiment of the present utility model.

[0014] In the diagram, 1. Evaporator; 2. Crystallizer; 3. Heater; 4. Circulating pump; 5. Feed pipe; 6. Steam exhaust pipe; 7. First discharge pipe; 8. First cylinder; 9. Second cylinder; 10. Liquid passage hole; 11. Second discharge pipe; 12. Propeller; 13. Circulation chamber; 14. Separation chamber; 15. Screw conveyor; 16. Third discharge pipe; 17. Motor. Detailed Implementation

[0015] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. The components of the embodiments of this utility model described and shown in the accompanying drawings can typically be arranged and designed in various different configurations.

[0016] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0017] In the description of this utility model, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0018] Example

[0019] like Figure 1 As shown, a pentaerythritol large particle crystallization device includes an evaporator separator 1, a crystallizer 2, a heater 3, a screw conveyor 15, and a circulating pump 4. The evaporator separator 1 and the crystallizer 2 are installed vertically together. The screw conveyor 15 is existing technology, which has a built-in screw conveyor and is driven by a motor to rotate and transport materials. It is commercially available. The upper part of the evaporator separator 1 is equipped with a feed pipe 5 and a steam discharge pipe 6. The bottom liquid outlet of the evaporator separator 1 is conical and extends into the crystallizer 2. The bottom of the crystallizer 2 is equipped with a first discharge pipe 7. The second discharge pipe 11 and the third discharge pipe 16 are installed on the upper part of the crystallizer 2. The third discharge pipe 16 is used to discharge the low-concentration supernatant located in the crystallizer 2 and near the upper part. One end of the circulation pump 4 is connected to the third discharge pipe 16. The heater 3 is selected as a shell and tube heat exchanger. The other end of the circulation pump 4 is connected to the heater 3. The other end of the heater 3 extends to the middle of the evaporator separator 1 for vacuum evaporation and concentration. The first discharge pipe 7 is connected to the lower feed port of the screw conveyor 15. The upper discharge port of the screw conveyor 15 is connected to the bottom of the evaporator separator 1.

[0020] like Figure 1As shown, a first cylinder 8 and a second cylinder 9 are also installed inside the crystallizer 2. The first cylinder 8 and the second cylinder 9 are arranged concentrically and vertically with the crystallizer 2. Both the first cylinder 8 and the second cylinder 9 are open at both ends. The upper and lower edges of the first cylinder 8 are respectively welded and sealed to the upper and lower surfaces of the crystallizer 2. The first cylinder 8 divides the crystallizer 2 into an outer separation chamber 14 and an inner circulation chamber 13. The second cylinder 9 is suspended and fixed in the circulation chamber 13. The second cylinder 9 can be fixed by multiple connecting rods. The second cylinder 9 divides the liquid in the circulation chamber 13 into an annular flow. The lower part of the first cylinder 8 is open. Multiple liquid passage holes 10 are provided, which are evenly distributed around the first cylinder 8. The first discharge pipe 7 is located between the first cylinder 8 and the second cylinder 9. The second discharge pipe 11 is located between the inner wall of the crystallizer 2 and the first cylinder 8. A propeller 12 and a motor 17 are installed on the crystallizer 2. The motor 17 is fixedly connected to the bottom center of the crystallizer 2. The output end of the motor 17 is connected to the propeller 12. The propeller 12 is located inside the second cylinder 9 and at the lower part of the second cylinder 9. The pushing direction of the propeller 12 is set upward, so that the solution in the second cylinder 9 moves upward and circulates.

[0021] The working principle of this invention is as follows: The mother liquor enters the vacuum evaporator 1 through the feed pipe 5 for concentration. The mother liquor forms a supersaturated solution and enters the crystallizer 2 through the bottom outlet of the evaporator 1 for crystallization. The propeller 12 pushes the crystallizing mother liquor to undergo multiple annular flows in the circulation chamber 13, prolonging the suspension time of the crystals and allowing them to grow continuously. At the same time, after growing, some of the crystals enter the separation chamber 14 for sedimentation and separation, while the other part is discharged into the bottom of the evaporator 1 through the screw conveyor 15 to preferentially contact the supersaturated solution for crystallization, further improving the particle size of the crystals before entering the separation chamber. The solution in section 14 undergoes gravity sedimentation. The supernatant enters heater 3, is heated, and then discharged into evaporator separator 1 for concentration. The crystals settled at the bottom are directly discharged. Using a screw conveyor 15 instead of a traditional pump body for conveying avoids damage to the crystals by centrifugation during the conveying process, maintaining the integrity of the crystal particle size. The propeller 12 is set vertically upward. Its rotation can push the solution upward, counteracting the supersaturated solution coming down from above, improving the mixing effect. At the same time, it makes the crystals flow upward and circulate, ensuring at least one cycle of seed growth time, resulting in larger and more uniform average particle size.

[0022] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. 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 pentaerythritol large-particle crystallization apparatus, characterized in that: The system includes an evaporator (1), a crystallizer (2), a heater (3), a screw conveyor (15), and a circulating pump (4). The outlet of the evaporator (1) extends into the crystallizer (2). The bottom of the crystallizer (2) is provided with a first discharge pipe (7) and a second discharge pipe (11). The upper part of the crystallizer (2) is provided with a third discharge pipe (16). One end of the circulating pump (4) is connected to the third discharge pipe (16), and the other end of the circulating pump (4) is connected to the heater (3). The other end of the heater (3) extends to the middle of the evaporator (1). The first discharge pipe (7) is connected to the inlet of the screw conveyor (15), and the outlet of the screw conveyor (15) is connected to the bottom of the evaporator (1).

2. The pentaerythritol large particle crystallization apparatus according to claim 1, characterized in that: The crystallizer (2) is provided with a first cylinder (8) and a second cylinder (9). The first cylinder (8), the second cylinder (9) and the crystallizer (2) are arranged concentrically. The first cylinder (8) and the second cylinder (9) are open at both ends. The first cylinder (8) is circumferentially sealed and fixed to the upper and lower surfaces of the crystallizer (2). The first cylinder (8) divides the crystallizer (2) into an external separation chamber (14) and an internal circulation chamber (13). The second cylinder (9) is suspended and fixed in the circulation chamber (13). The lower part of the first cylinder (8) is provided with a liquid passage hole (10).

3. The pentaerythritol large particle crystallization apparatus according to claim 2, characterized in that: The crystallizer (2) is equipped with a propeller (12), which is located at the lower part of the second cylinder (9).

4. The pentaerythritol large particle crystallization apparatus according to claim 3, characterized in that: The propeller (12) is positioned with its pushing direction facing upwards.

5. The pentaerythritol large particle crystallization apparatus according to claim 1, characterized in that: The heater (3) is a shell-and-tube heat exchanger.

6. The pentaerythritol large particle crystallization apparatus according to claim 3, characterized in that: A motor (17) is provided on the crystallizer (2), the motor (17) is located at the bottom center of the crystallizer (2), and the output end of the motor (17) is connected to the propeller (12).

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