A mixed diamine continuous separation system

Abstract

The application discloses a mixed diamine continuous separation system, which comprises a pretreatment unit, a deep coke removal unit and an isomer separation unit, wherein the deep coke removal unit comprises a dehydration tower, a wiped film evaporator and a tar tank; and the isomer separation unit comprises a meta-tower.

Description

Technical Field

[0001] This invention relates to the field of mixed diamine separation technology, and more particularly to a continuous mixed diamine separation system. Background Technology

[0002] Diamine compounds, especially the three isomers of phenylenediamine (meta, ortho, and para), are important chemical intermediates widely used in dyes, epoxy resin curing agents, rubber additives, and polymer materials. Industrial production often yields mixed diamines; therefore, efficiently and economically separating them into high-purity single-component products is crucial for improving the quality and value of downstream products.

[0003] Currently, the separation of mixed diamines mainly relies on distillation technology. Diamines, especially at higher temperatures, are highly reactive and prone to side reactions such as oxidation and condensation, generating high-molecular polymers or tar-like substances. These heavy components and tar gradually accumulate and coke on the walls of reboilers, reboilers, and heat exchangers, leading to a sharp decline in heat transfer efficiency and an increase in system pressure. In severe cases, manual cleaning is necessary, significantly impacting the continuity and stability of production and increasing maintenance costs and safety hazards. Traditional batch or simple continuous separation processes struggle to maintain high separation efficiency and product purity over long periods.

[0004] Therefore, developing an integrated system that can operate continuously and stably, effectively suppress coking, and thus achieve efficient and high-purity separation of mixed diamines has become a technical challenge that urgently needs to be solved in this field. Summary of the Invention

[0005] To address the problems mentioned in the background section, the present invention provides a continuous separation system for mixed diamines.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A continuous separation system for mixed diamines includes a pretreatment unit, a deep decoking unit, and an isomer separation unit. The system includes a dehydration tower and a dehydration reflux tank. The top of the dehydration tower is connected to a dehydration tower condenser via a pipe. The outlet of the dehydration tower condenser is connected to the top of the dehydration reflux tank. The bottom outlet of the dehydration reflux tank is connected to the top reflux outlet of the dehydration tower via a pipe.

[0008] The deep decoking unit includes a de-weighting tower, a scraped film evaporator, and a tar tank;

[0009] The isomer separation unit includes a meta tower, an adjacent tower, and a para tower;

[0010] The scraped film evaporator has a liquid inlet on one side near the top, a tar discharge outlet at the bottom, and an exhaust outlet at the top.

[0011] Preferably, the scraped film evaporator is provided with a heating jacket on its exterior, and the heating jacket is provided with a heat medium inlet pipe and a heat medium outlet pipe.

[0012] Preferably, the scraped film evaporator has a vertical rotating shaft inside, which is driven to rotate by a power input device at the top of the scraped film evaporator, and a distribution umbrella is provided on the outside of the vertical rotating shaft near the top.

[0013] Preferably, multiple scraping plates are provided on both sides of the vertical rotating shaft, the distribution umbrella has a frustum-shaped structure, and multiple protrusions are evenly distributed on the side of the distribution umbrella.

[0014] Preferably, the liquid inlet extends into the interior of the scraped film evaporator and is connected to a distribution ring pipe. The bottom end of the distribution ring pipe is provided with multiple liquid outlets, which are evenly distributed at the bottom end of the distribution ring pipe. The scraped film evaporator is also provided with an alternating sealing mechanism.

[0015] Preferably, the alternating sealing mechanism includes a swing disk with multiple arc-shaped limiting ports, and multiple slide rails are fixed inside the scraped film evaporator by a fixing frame, with sealing connecting rods slidably installed on the slide rails.

[0016] Preferably, the sealing connecting rod corresponds to the arc-shaped limiting port, and the sealing connecting rod passes through the arc-shaped limiting port through the swing disk. The swing disk is rotatably mounted on the fixed frame, and a sealing plate corresponding to the liquid outlet is fixed on the sealing connecting rod.

[0017] Preferably, the bending directions of adjacent arc-shaped limiting ports are opposite, the vertical rotating shaft moves through the swing disk through the through hole, and the top and bottom ends of the swing disk are both distributed with meshing teeth. Incomplete gears are rotatably installed above and below the swing disk through the mounting shaft, and the incomplete gears correspond to the meshing teeth.

[0018] Preferably, a first gear is fixed on one side of the incomplete gear near the vertical shaft, and a second gear is fixed on the vertical shaft. The first gear and the second gear mesh with each other. Synchronous pulleys are fixed on both mounting shafts, and the two synchronous pulleys are driven by a synchronous belt.

[0019] Preferably, the distribution angle of the outer teeth of the incomplete gear is less than 180 degrees, and the two incomplete gears do not mesh with the meshing teeth on the oscillating disk at the same time.

[0020] Compared with the prior art, the beneficial effects of the present invention are:

[0021] 1. A complete continuous process flow is formed by organically linking three units: pretreatment, deep decoking, and precise isomer separation. The pretreatment unit removes moisture from the raw materials, creating stable conditions for the subsequent high-temperature unit; the deep decoking unit fundamentally alleviates the coking problem; and the isomer separation unit achieves high product purification through multi-tower distillation. The entire system is highly automated, overcoming the drawbacks of traditional processes that require frequent shutdowns for cleaning due to coking, and ensuring the continuity and stability of production.

[0022] 2. The alternating sealing mechanism forces the alternating opening and closing of adjacent liquid outlets. This design, on the one hand, allows the feed liquid to dynamically and intermittently change the distribution area on the heated wall surface, avoiding excessively thick liquid film and overheating and coking caused by continuous local feeding; on the other hand, by instantaneously closing half of the liquid outlets, the pressure of the liquid ejected from the open outlets is increased, allowing it to impact the wall surface with higher kinetic energy, achieving a more uniform and proactive initial distribution.

[0023] 3. Alternating opening and closing allows different areas of the heated wall surface to alternately enter the cycle of material reception, evaporation, and scraping cleaning. In areas not directly receiving material, the rotating scraper can more thoroughly scrape away any early polymers that may be adhering to the wall surface, achieving online self-cleaning and maintaining the high efficiency of the heat transfer surface over a long period. The high-speed rotating scraper scrapes the material into an extremely thin and turbulent liquid film, greatly enhancing the heat transfer and evaporation process.

[0024] 4. The system has a high degree of integration, with clearly defined functions for each unit and smooth connections. The internal mechanical structure design of the scraped film evaporator utilizes the power of the main rotating shaft to drive the sealing mechanism, eliminating the need for an additional power source and achieving both functional integration and energy savings. Attached Figure Description

[0025] 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.

[0026] Figure 1 This is a process flow diagram of the present invention;

[0027] Figure 2 This is a front view of the scraped film evaporator of the present invention;

[0028] Figure 3 This is a cross-sectional view of the scraped film evaporator of the present invention;

[0029] Figure 4 This is a bottom view of the distribution ring pipe of the present invention;

[0030] Figure 5This is a top view of the distribution ring pipe of the present invention;

[0031] Figure 6 This is a front view of the distribution ring pipe of the present invention;

[0032] Figure 7 This is a first-view perspective perspective view of the oscillating disk of the present invention;

[0033] Figure 8 This is a second-view perspective perspective view of the oscillating disk of the present invention;

[0034] Figure 9 This is a third-view perspective view of the oscillating disk of the present invention;

[0035] In the diagram: 1. Dehydration tower; 2. Dehydration reflux tank; 3. Heavy weight removal tower; 4. Scraped film evaporator; 5. Tar tank; 6. Inter-position tower; 7. Adjacent position tower; 8. Parallel position tower; 401. Heating jacket; 4011. Heat medium inlet pipe; 4012. Heat medium outlet pipe; 402. Liquid inlet; 4021. Tar outlet; 4023. Exhaust port; 403. Vertical rotating shaft; 4031. Scraped film plate; 4032. Distribution umbrella; 403 3. Raised bar; 4034. Second gear; 404. Distribution ring pipe; 4041. Liquid outlet; 405. Swinging disc; 4051. Arc-shaped limiting port; 4052. Meshing teeth; 406. Fixing frame; 4061. Slide rail; 4062. Sealing connecting rod; 4063. Sealing plate; 407. Mounting shaft; 4071. Synchronous pulley; 4072. Synchronous belt; 4073. Incomplete gear; 4074. First gear. Detailed Implementation

[0036] 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.

[0037] Example 1

[0038] Reference Figure 1-9 A continuous separation system for mixed diamines includes a pretreatment unit, a deep decoking unit, and an isomer separation unit. The system includes a dehydration tower 1 and a dehydration reflux tank 2. The top of the dehydration tower 1 is connected to the dehydration tower condenser via a pipe. The outlet of the dehydration tower condenser is connected to the top of the dehydration reflux tank 2. The bottom outlet of the dehydration reflux tank 2 is connected to the top reflux outlet of the dehydration tower 1 via a pipe.

[0039] The deep decoking unit includes a de-coking tower 3, a scraped film evaporator 4, and a tar tank 5;

[0040] The isomer separation unit includes meta tower 6, adjacent tower 7, and para tower 8;

[0041] The scraped film evaporator 4 has a liquid inlet 402 near the top on one side, a tar discharge port 4021 at the bottom, and an exhaust port 4023 at the top.

[0042] The scraped film evaporator 4 is externally equipped with a heating jacket 401. The heating jacket 401 has a heat medium inlet pipe 4011 and a heat medium outlet pipe 4012. High-temperature heat medium (entering through the heat medium inlet pipe 4011 and exiting through the heat medium outlet pipe 4012) is introduced into the heating jacket 401 of the scraped film evaporator 4 to heat the inner wall of the cylinder. A vertical rotating shaft 403, driven by a power unit, rotates at high speed, and multiple scraper blades 4031 mounted on it instantly spread the material flowing to the inner wall into an extremely thin and turbulent liquid film. The liquid film is rapidly heated on the heated surface, and residual light components such as diamine evaporate violently into steam.

[0043] The scraped film evaporator 4 has a vertical rotating shaft 403 inside. The vertical rotating shaft 403 is driven to rotate by a power input device at the top of the scraped film evaporator 4. A distribution umbrella 4032 is provided on the outside of the vertical rotating shaft 403 near the top. Multiple scraping plates 4031 are provided on both sides of the vertical rotating shaft 403. The distribution umbrella 4032 has a frustum-shaped structure and multiple protrusions 4033 are evenly distributed on the side of the distribution umbrella 4032. The liquid is guided by the distribution umbrella 4032 and flows evenly to the gap between the distribution umbrella 4032 and the inner wall of the scraped film evaporator 4. By rotating and swinging the distribution umbrella 4032, the liquid can be evenly distributed along the circumference of the inner wall of the cylinder.

[0044] The inlet 402 extends into the interior of the scraped film evaporator 4 and is connected to a distribution ring pipe 404. The bottom end of the distribution ring pipe 404 is provided with multiple outlets 4041, which are evenly distributed at the bottom end of the distribution ring pipe 404. The scraped film evaporator 4 is also provided with an alternating sealing mechanism. The material enters through the inlet 402 and is evenly distributed along the circumferential direction of the inner wall of the cylinder through the internal distribution ring pipe 404 and the multiple outlets 4041 at its bottom.

[0045] Example 2

[0046] Reference Figure 1-9The difference between this embodiment and embodiment 1 is that the alternating sealing mechanism includes a swing disk 405, which has multiple arc-shaped limiting ports 4051. The scraped film evaporator 4 also has multiple slide rails 4061 fixed inside by a fixing frame 406. A sealing connecting rod 4062 is slidably installed on the slide rail 4061. The sealing connecting rod 4062 corresponds to the arc-shaped limiting ports 4051, and the sealing connecting rod 4062 passes through the swing disk 405 through the arc-shaped limiting ports 4051. The swing disk 405 is rotatably installed on the fixing frame 406, and a sealing plate 4063 corresponding to the liquid outlet 4041 is fixed on the sealing connecting rod 4062.

[0047] By swinging the externally of the swing disk 405, the sealing connecting rod 4062 can be pushed to move back and forth along the slide rail 4061 through the limiting action of the arc-shaped limiting port 4051. During the reciprocating movement, the sealing plate 4063 can be driven to move back and forth, thereby intermittently sealing the liquid outlet 4041. This avoids thermal decomposition and coking in certain areas due to long-term material reception and excessively thick liquid film. In areas that are not directly receiving material, the liquid film on the inner wall is extremely thin or briefly interrupted. The scraper plate 4031 can more effectively scrape off early polymers or coking materials that may be attached to the inner wall, keeping the heat transfer surface clean and thus improving the self-cleaning effect. This dynamic material distribution allows the entire heating surface to be utilized more evenly, maintaining a stable and efficient total evaporation rate.

[0048] Among them, the bending directions of adjacent arc-shaped limiting ports 4051 are opposite, the vertical rotating shaft 403 passes through the swing disk 405 through the through hole, and the top and bottom of the swing disk 405 are both distributed with meshing teeth 4052. The top and bottom of the swing disk 405 are both rotatably mounted with incomplete gears 4073 through the mounting shaft 407, and the incomplete gears 4073 and the meshing teeth 4052 are matched accordingly.

[0049] The staggered arc-shaped limiting ports 4051 ensure that adjacent liquid outlets 4041 do not open and close synchronously, but alternately. This alternating closure of half of the liquid outlets 4041 can increase the pressure of the liquid ejection and further improve the liquid distribution effect.

[0050] Example 3

[0051] Reference Figure 1-9The difference between this embodiment and embodiment 2 is that, in order to drive the swing disk 405 to swing back and forth, a first gear 4074 is fixed on one side of the incomplete gear 4073 near the vertical rotating shaft 403, and a second gear 4034 is fixed on the vertical rotating shaft 403. The first gear 4074 and the second gear 4034 mesh with each other. Synchronous pulleys 4071 are fixed on both mounting shafts 407. The two synchronous pulleys 4071 are driven by a synchronous belt 4072. The distribution angle of the outer teeth of the incomplete gear 4073 is less than 180 degrees, and the two incomplete gears 4073 do not mesh with the meshing teeth 4052 on the swing disk 405 at the same time.

[0052] When the vertical shaft 403 rotates continuously, the second gear 4034 follows suit and rotates continuously. This causes the first gear 4074 and the second gear 4034 to mesh with each other, driving one of the incomplete gears 4073 to rotate continuously. Due to the transmission of the synchronous pulley 4071 and the synchronous belt 4072, the two incomplete gears 4073 rotate continuously and synchronously. Since the two incomplete gears 4073 do not mesh with the meshing teeth 4052 on the swing disk 405 at the same time, when the upper incomplete gear 4073 meshes with the meshing teeth 4052, it drives the swing disk 405 to rotate clockwise by an angle. After the lower incomplete gear 4073 meshes with the meshing teeth 4052, it drives the swing disk 405 to rotate counterclockwise by the same angle, thereby achieving the purpose of continuous reciprocating swing.

[0053] 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.

[0054] 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.

[0055] 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.

[0056] 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 continuous separation system for mixed diamines, comprising a pretreatment unit, a deep decoking unit, and an isomer separation unit, characterized in that: The structure includes a dehydration tower (1) and a dehydration reflux tank (2). The top of the dehydration tower (1) is connected to the dehydration tower condenser through a pipe. The liquid outlet of the dehydration tower condenser is connected to the top of the dehydration reflux tank (2). The bottom outlet of the dehydration reflux tank (2) is connected to the top reflux outlet of the dehydration tower (1) through a pipe. The deep decoking unit includes a decoking tower (3), a scraped film evaporator (4), and a tar tank (5). The isomer separation unit includes a meta tower (6), an adjacent tower (7), and a para tower (8). The scraped film evaporator (4) has a liquid inlet (402) near the top on one side, a tar discharge port (4021) at the bottom, and an exhaust port (4023) at the top.

2. The continuous separation system for mixed diamines according to claim 1, characterized in that: The scraped film evaporator (4) is provided with a heating jacket (401) on the outside, and the heating jacket (401) is provided with a heat medium inlet pipe (4011) and a heat medium outlet pipe (4012).

3. The continuous separation system for mixed diamines according to claim 1, characterized in that: The scraped film evaporator (4) has a vertical rotating shaft (403) inside. The vertical rotating shaft (403) is driven to rotate by a power input device at the top of the scraped film evaporator (4). A distribution umbrella (4032) is provided on the outside of the vertical rotating shaft (403) near the top.

4. The continuous separation system for mixed diamines according to claim 3, characterized in that: The vertical rotating shaft (403) has multiple scraping plates (4031) on both sides, the distribution umbrella (4032) is a frustum-shaped structure, and the side of the distribution umbrella (4032) has multiple protrusions (4033) evenly distributed.

5. The continuous separation system for mixed diamines according to claim 3, characterized in that: The inlet (402) extends into the interior of the scraped film evaporator (4) and is connected to a distribution ring pipe (404). The bottom end of the distribution ring pipe (404) is provided with multiple outlets (4041). The outlets (4041) are evenly distributed at the bottom end of the distribution ring pipe (404). The scraped film evaporator (4) is also provided with an alternating sealing mechanism.

6. The continuous separation system for mixed diamines according to claim 5, characterized in that: The alternating sealing mechanism includes a swing disk (405), on which multiple arc-shaped limiting ports (4051) are provided. Multiple slide rails (4061) are also fixed inside the scraped film evaporator (4) by a fixing frame (406), and sealing connecting rods (4062) are slidably installed on the slide rails (4061).

7. A continuous separation system for mixed diamines according to claim 6, characterized in that: The sealing connecting rod (4062) corresponds to the arc-shaped limiting port (4051), and the sealing connecting rod (4062) passes through the arc-shaped limiting port (4051) and passes through the swing disk (405). The swing disk (405) is rotatably mounted on the fixed frame (406), and a sealing plate (4063) corresponding to the liquid outlet (4041) is fixed on the sealing connecting rod (4062).

8. The continuous separation system for mixed diamines according to claim 7, characterized in that: The adjacent arc-shaped limiting ports (4051) have opposite bending directions. The vertical rotating shaft (403) passes through the swing disk (405) through the through hole. The top and bottom of the swing disk (405) are both equipped with meshing teeth (4052). The top and bottom of the swing disk (405) are both equipped with incomplete gears (4073) through the mounting shaft (407). The incomplete gears (4073) and the meshing teeth (4052) are matched accordingly.

9. A continuous separation system for mixed diamines according to claim 8, characterized in that: One of the incomplete gears (4073) has a first gear (4074) fixed on one side near the vertical shaft (403), and a second gear (4034) is fixed on the vertical shaft (403). The first gear (4074) and the second gear (4034) mesh with each other. Synchronous pulleys (4071) are fixed on both mounting shafts (407), and the two synchronous pulleys (4071) are driven by a synchronous belt (4072).

10. A continuous separation system for mixed diamines according to claim 9, characterized in that: The distribution angle of the outer teeth of the incomplete gear (4073) is less than 180 degrees, and the two incomplete gears (4073) do not mesh with the meshing teeth (4052) on the swing disk (405) at the same time.

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