Novel self-balancing phosgenation reactor

Abstract

The invention provides a self-balancing type novel phosgenation reactor which comprises a reactor shell, and an upper flow guide pipe, a tower tray piece and a lower flow guide pipe are sequentially connected into the reactor shell; the shell side is provided with a heat exchange medium steam inlet and a condensate outlet; the redistributor is fixedly connected with the reactor shell, and the redistributor is positioned below the feeding hole; a falling film device is mounted in the lower flow guide pipe; according to the novel self-balancing phosgenation reactor, the heat exchange and separation efficiency is improved, the stable reaction environment is guaranteed, the cooling and heating functions are achieved through the upper flow guide pipe and the lower flow guide pipe respectively, the upper flow guide pipe cools a gas phase to separate heavy components, and the lower flow guide pipe heats materials to promote light components to be vaporized; the two-stage synergistic effect synchronously realizes high-efficiency heat exchange and component separation at a lower temperature difference, maintains a stable environment required by phosgenation thermal reaction, accelerates a positive reaction process and reduces side reactions.

Description

Technical Field

[0001] This invention belongs to the field of phosgenation reactor technology, specifically relating to a novel self-balancing phosgenation reactor. Background Technology

[0002] Phosgene reaction is usually divided into two stages: cold reaction and hot reaction. In the cold reaction stage, phosgene reacts with primary amines to produce carbamoyl chloride and amine hydrochloride. In the hot reaction stage, the above products need to be converted into isocyanate products in a phosgene environment.

[0003] Traditional phosgenation thermal reactions often employ equipment such as tubular heat exchangers, reactive distillation columns, or batch reactors. However, these traditional devices have significant drawbacks: tubular heat exchangers are prone to localized reaction anomalies due to uneven heat exchange; reactive distillation columns have limited operational flexibility and are difficult to adapt to different operating conditions; and batch reactors are prone to clogging. Furthermore, all three types generally involve large online phosgen volumes and high energy consumption, which increases production costs and may exacerbate side reactions due to unstable reaction environments, affecting product purity and production efficiency. Therefore, there is an urgent need for a reactor structure that can achieve both high heat exchange and separation efficiency at lower temperature differences, while avoiding clogging and reducing phosgen consumption and energy consumption, in order to optimize the phosgenation thermal reaction process. Summary of the Invention

[0004] This invention addresses the shortcomings of existing technologies by providing a novel self-balancing phosgenation reactor, comprising a reactor shell. Inside the reactor shell, an upper guide pipe, tray internals, and a lower guide pipe are sequentially connected. The lower guide pipe has a reactant inlet and a liquid outlet on its tube side, and a heat exchange medium steam inlet and a condensate outlet on its shell side. A redistributor is located at the upper end of the lower guide pipe, fixedly connected to the reactor shell and positioned below the inlet. A falling film device is installed inside the lower guide pipe. The upper and lower ends of the upper guide pipe are fixedly connected to the phosgenation reactor tube side using a double-tubesheet heat exchanger structure.

[0005] Furthermore, the falling film device includes a falling film distribution pipe, a liquid blocking cap, a linkage liquid blocking rod, a limiting sleeve, and a liquid blocking distribution orifice plate; the falling film distribution pipe is shaped like an inverted funnel, and a circular liquid blocking distribution orifice plate is provided below the falling film distribution pipe; a liquid blocking cap is provided at the top of the falling film distribution pipe, and the arc-shaped liquid blocking cap is welded to the linkage liquid blocking rod; a disk with a diameter larger than the orifice diameter of the liquid blocking distribution orifice plate is provided at the lower part of the linkage liquid blocking rod, and a limiting sleeve is fitted on the linkage liquid blocking rod.

[0006] Furthermore, a gap is formed between the bottom of the falling film distribution pipe and the inner wall of the lower guide pipe, and a gap is also formed between the liquid blocking distribution orifice plate and the inner wall of the lower guide pipe, and the size of both gaps is 1-1.5mm.

[0007] Furthermore, the upper guide tube shell side is provided with a heat exchange medium cooling water inlet and a cooling water outlet.

[0008] Furthermore, the tray internals are located between the upper and lower guide pipes, and the tray internals are connected to the reactor shell.

[0009] Furthermore, the lower guide pipe is connected to the internal components of the tray, and an exhaust port is provided at the top of the upper part of the reactor shell.

[0010] Furthermore, the falling film device is secured to an internal perforated plate of uniform height inside the reactor via a snap-fit ​​structure.

[0011] This invention has at least one of the following advantages:

[0012] 1. This invention achieves cooling and heating functions through two sets of upper and lower guide pipes respectively. The upper guide pipe cools the gas phase to separate heavy components, while the lower guide pipe heats the material to promote the vaporization of light components. The two sections work together to achieve efficient heat exchange and component separation at a low temperature difference, while maintaining the stable environment required for the phosgenation heat reaction, accelerating the positive reaction process and reducing the occurrence of side reactions.

[0013] 2. The tray internals between the two sets of guide tubes of the present invention can perform local distillation on the rising light components, reduce the product and phosgene content in the light components, and the concentrated heavy components are returned to the lower guide tube to participate in the reaction again, which reduces the online amount and excess amount of phosgene, reduces the energy consumption of phosgene recovery, and improves the resource utilization rate.

[0014] 3. The falling film device in the lower guide tube of the present invention forms a uniform liquid film of material through a specific gap (1-1.5mm), which increases the heat exchange area, improves the heating uniformity, and prevents material accumulation and blockage. At the same time, the liquid-blocking structure of the falling film device can block the insufficiently heated cold liquid when the liquid phase flow is abnormal, so as to avoid affecting the reaction efficiency and pipe blockage.

[0015] 4. The upper and lower guide tubes of this invention adopt a double tube sheet heat exchanger structure and are connected to the reactor body, which effectively avoids the heat exchange medium from seeping into the material side through the tube sheet, ensuring the purity of the material and the safety of the reaction; and the heat exchange medium (cooling medium can be cooling water, ethylene glycol solution, etc., and heating medium can be steam, heat transfer oil, etc.) and the inlet and outlet directions of the upper and lower guide tubes are flexible, adapting to different production conditions and installation requirements. Attached Figure Description

[0016] Figure 1 The figure shown is a three-dimensional schematic diagram of the structure of the present invention;

[0017] Figure 2 The diagram shown is a schematic representation of the structure of this invention.

[0018] Figure 3 The structure of the present invention is shown. Figure 2 Schematic diagram of part A in the middle.

[0019] In the diagram: 1. Reactor shell; 2. Upper guide pipe; 3. Lower guide pipe; 4. Cooling water inlet; 5. Cooling water outlet; 6. Steam inlet; 7. Condensate outlet; 8. Feed inlet; 9. Drain outlet; 10. Exhaust outlet; 11. Tray internals; 12. Falling film distribution pipe; 13. Liquid blocking cap; 14. Limiting sleeve; 15. Liquid blocking distribution orifice plate; 16. Liquid distributor; 17. Redistributor. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of the invention.

[0021] This invention provides, by way of example, a novel self-balancing phosgenation reactor, such as... Figure 1-3 As shown, the reactor includes a reactor shell 1, inside which are connected in sequence an upper guide pipe 2, a tray internal 11, and a lower guide pipe 3; the lower guide pipe 3 has a reactant inlet 8 and a liquid outlet 9 on its tube side, and a heat exchange medium steam inlet 6 and a condensate outlet 7 on its shell side; a redistributor 17 is provided at the upper end of the lower guide pipe 3, and the redistributor 17 is fixedly connected to the reactor shell 1, and the redistributor 17 is located below the feed inlet 8; a falling film device is installed inside the lower guide pipe 3; the upper and lower ends of the upper guide pipe 2 are fixedly connected to the tube side of the phosgenation reactor using a double tube sheet heat exchanger structure.

[0022] The operation of this device is as follows: The reactor shell 1 provides installation and housing space for the overall structure. Inside, the upper guide pipe 2, the tray internals 11, and the lower guide pipe 3 are connected sequentially, forming the core flow channel for material reaction and separation. Material enters through the feed inlet 8 in the lower guide pipe 3, is initially evenly distributed by the redistributor 17 located below the feed inlet 8 and fixed to the shell, and then flows into the falling film device inside the lower guide pipe 3. The lower guide pipe 3 shell side is supplied with heat exchange medium through the steam inlet 6 and discharged through the condensate outlet 7, providing heat to the material in the tube side. The upper guide pipe 2 is fixed to the reactor tube side using a double tube sheet heat exchanger structure, achieving a stable connection while preventing contact between the shell-side heat exchange medium and the tube-side material, ensuring material flow stability and purity.

[0023] The present invention provides an exemplary falling film device, such as... Figure 2 and Figure 3As shown, it includes a falling film liquid distribution tube 12, a liquid blocking cap 13, a linkage liquid blocking rod, a limiting sleeve 14, and a liquid blocking distribution orifice plate 15; the falling film liquid distribution tube 12 is shaped like an inverted funnel, and a circular liquid blocking distribution orifice plate 15 is provided below the falling film liquid distribution tube 12; a liquid blocking cap 13 is provided at the top of the falling film liquid distribution tube 12, and the arc-shaped liquid blocking cap 13 is welded to the linkage liquid blocking rod; a disk with a diameter larger than the orifice diameter of the liquid blocking distribution orifice plate 15 is provided at the lower part of the linkage liquid blocking rod, and a limiting sleeve 14 is sleeved on the linkage liquid blocking rod.

[0024] At this time, the hollow tubular structure at the top of the inverted funnel-shaped falling film distribution pipe 12 receives the material, and the umbrella-shaped design transitions from top to bottom to disperse the material. The liquid-blocking distribution orifice plate 15 below its large opening further guides the material flow. The arc-shaped liquid-blocking cap 13 at the top of the falling film distribution pipe 12 is welded to the linkage liquid-blocking rod to ensure that the two are in the same position. The disc at the bottom of the linkage liquid-blocking rod has a diameter larger than the orifice diameter of the liquid-blocking distribution orifice plate 15, which can block the material from passing through the orifice plate under certain circumstances. The limiting sleeve 14 sleeved on the linkage liquid-blocking rod restricts the rod's displacement, ensuring that the relative positions of all components of the entire falling film device are stable, and realizing the orderly flow and distribution of materials.

[0025] The present invention provides an exemplary falling film device, such as... Figure 2 and Figure 3 As shown, a gap is formed between the bottom of the falling film distribution pipe 12 and the inner wall of the lower guide pipe 3, and a gap is also formed between the liquid blocking distribution orifice plate 15 and the inner wall of the lower guide pipe 3, and the size of both gaps is 1-1.5mm.

[0026] This setup provides a specific channel for material flow through a 1-1.5mm gap between the bottom of the falling film distribution pipe 12, the liquid distribution orifice plate 15, and the inner wall of the lower guide pipe 3. After the material flows out of the falling film distribution pipe 12, it forms a continuous liquid film along the gap on the inner wall of the lower guide pipe 3. The gap size avoids material blockage due to being too small, and also prevents the material from failing to form a uniform liquid film due to being too large, ensuring that the material can fully contact the heat exchange medium in the shell side of the lower guide pipe 3 to achieve efficient heat exchange.

[0027] The present invention provides an exemplary upper guide tube, such as... Figure 2 and Figure 3 As shown, the upper guide tube 2 has a heat exchange medium cooling water inlet 4 and a cooling water outlet 5 on its shell side.

[0028] At this time, the cooling water inlet 4 of the upper guide tube 2 shell side is used to introduce the cooling medium, and the cooling water outlet 5 is used to discharge the cooled medium after heat exchange. The two constitute the circulation channel of the cooling medium. When the cooling medium flows in the shell side, it exchanges heat with the material in the tube side of the upper guide tube 2. It cools the material by absorbing the heat of the material, and provides temperature conditions for the subsequent separation of components in the material.

[0029] This invention provides an exemplary tray internal, such as... Figure 2 and Figure 3 As shown, the tray internals 11 are located between the upper guide pipe 2 and the lower guide pipe 3, and the tray internals 11 are connected to the reactor shell 1.

[0030] At this time, the tray internals 11 are located between the upper guide pipe 2 and the lower guide pipe 3 and are connected to the shell. Its fixed installation position makes it the intermediate link for material transfer between the upper and lower guide pipes. Different types of trays, such as single overflow trays and double overflow trays, as well as different types of float valves, such as bubble cap valves, float valves, and tongue valves, can guide the gas phase material and liquid phase material to fully contact on the tray surface through their own structural characteristics, providing space and conditions for mass and heat transfer between the gas and liquid phases, and realizing the initial separation of material components.

[0031] The present invention provides, by way of example, a lower guide tube, such as... Figure 2 and Figure 3 As shown, the lower guide pipe 3 is connected to the inner part of the tray 11, and the upper top of the reactor shell 1 is provided with an exhaust port 10.

[0032] At this point, the lower guide pipe 3 is connected to the tray internals 11, allowing the vaporized material in the lower guide pipe 3 to directly enter the tray internals 11. Simultaneously, the liquid material in the tray internals 11 can also flow back to the lower guide pipe 3, forming a circulating flow channel between the two. This connection allows the heat provided by the lower guide pipe 3 to work in conjunction with the separation function of the tray internals 11. After being heated in the lower guide pipe 3, the material enters the tray internals 11 for separation, and a portion of the separated material returns to the lower guide pipe 3, ensuring the continuity of the reaction and separation process. The exhaust port 10 at the top of the upper part of the reactor shell 1 serves as a discharge channel for the gaseous material, receiving the non-condensable gas generated after being processed by the upper guide pipe 2. When the upper guide pipe 2 cools and separates the material, the non-condensable gas, due to its lower density, accumulates upwards and is eventually discharged from the reactor through the exhaust port 10, preventing the accumulation of non-condensable gas in the shell from affecting pressure stability and material flow, and ensuring the pressure balance of the entire reaction system.

[0033] The present invention provides an exemplary falling film device, such as... Figure 2 and Figure 3 As shown, the falling film device is secured to the internal perforated plate at the same height inside the reactor via a snap-fit ​​structure.

[0034] At this point, the falling film device is secured to the internal perforated plate at the same height inside the reactor via a snap-fit ​​structure. This fixing method ensures that the falling film device remains stable during equipment operation and will not shift due to material flow impact or equipment vibration. The stable installation position ensures that the gap size between the falling film distribution pipe 12, the liquid blocking distribution perforated plate 15, and the inner wall of the lower guide pipe 3 remains constant, thereby maintaining the stability of the liquid film formed by the material and ensuring that the falling film device continues to perform its material distribution function.

[0035] It should be noted and understood that various modifications and improvements can be made to the invention described in the above detailed description without departing from the spirit and scope of the claims. Therefore, the scope of the claimed solutions is not limited to any specific exemplary teachings given.

Claims

1. A novel self-balancing phosgenation reactor, comprising a reactor shell (1), characterized in that, The reactor shell (1) is connected in sequence with an upper guide pipe (2), a tray internal (11), and a lower guide pipe (3); the lower guide pipe (3) has a reactant inlet (8) and a liquid outlet (9) on its tube side, and a heat exchange medium steam inlet (6) and a condensate outlet (7) on its shell side; a redistributor (17) is provided at the upper end of the lower guide pipe (3), and the redistributor (17) is fixedly connected to the reactor shell (1), and the redistributor (17) is located below the inlet (8); a falling film device is installed inside the lower guide pipe (3); the upper and lower ends of the upper guide pipe (2) are fixedly connected to the tube side of the phosgenation reactor using a double tube sheet heat exchanger structure.

2. The self-balancing novel phosgenation reactor according to claim 1, characterized in that, The falling film device includes a falling film distribution pipe (12), a liquid blocking cap (13), a linkage liquid blocking rod (17), a limiting sleeve (14), and a liquid blocking distribution orifice plate (15). The falling film distribution pipe (12) is shaped like an inverted funnel, and a circular liquid blocking distribution orifice plate (15) is provided below the falling film distribution pipe (12). The top of the falling film distribution pipe (12) is provided with a liquid blocking cap (13), and the arc-shaped liquid blocking cap (13) is welded to the linkage liquid blocking rod (17). The lower part of the linkage liquid blocking rod (17) is provided with a disc with a diameter larger than the aperture of the liquid blocking distribution orifice plate (15), and a limiting sleeve (14) is sleeved on the linkage liquid blocking rod (17).

3. The self-balancing novel phosgenation reactor according to claim 2, characterized in that, A gap is formed between the bottom of the falling film distribution pipe (12) and the inner wall of the lower guide pipe (3), and a gap is also formed between the liquid blocking distribution orifice plate (15) and the inner wall of the lower guide pipe (3), and the size of both gaps is 1-1.5mm.

4. The self-balancing novel phosgenation reactor according to claim 1, characterized in that, The upper guide pipe (2) has a heat exchange medium cooling water inlet (4) and a cooling water outlet (5) on its shell side.

5. The self-balancing novel phosgenation reactor according to claim 1, characterized in that, The tray internals (11) are located between the upper guide pipe (2) and the lower guide pipe (3), and the tray internals (11) are connected to the reactor shell (1).

6. The self-balancing novel phosgenation reactor according to claim 1, characterized in that, The lower guide pipe (3) is connected to the inner part of the tray (11), and an exhaust port (10) is provided at the top of the upper part of the reactor shell (1).

7. The self-balancing novel phosgenation reactor according to claim 2, characterized in that, The falling film device is fastened to the internal perforated plate at the same height inside the reactor via a snap-fit ​​structure.

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