Azeotropic distillation continuous water removal system

Abstract

The utility model provides a kind of azeotropic distillation continuous water separation system, it is applicable to dichloromethane, chloroform, dichloroethane, chloroethane, chlorobenzene, o-dichlorobenzene solvent azeotropic water separation using of specific gravity greater than water, its technical scheme is: including distillation kettle, the top of distillation kettle is equipped with mixed gas outlet pipeline, mixed gas outlet pipeline other end is connected to the side wall top of liquid separator, the top of liquid separator is equipped with condenser, the side wall top of liquid separator is equipped with first liquid outlet pipeline, the bottom of liquid separator is equipped with second liquid outlet pipeline.The utility model has the beneficial effects that (1) strengthen phase separation efficiency, improve water separation precision;(2) optimize operation visibility, improve control precision;(3) enhance reflux stability, prevent risk of reverse suction.

Description

TECHNICAL FIELD

[0001] The utility model belongs to compound separation technical field especially, it relates to a kind of azeotropic distillation continuous water separation system. BACKGROUND

[0002] Azeotropic distillation is the key process of separating liquid mixture in organic synthesis, fine chemical industry and other fields, especially widely used in the scene needing to remove water generated in reaction system (such as esterification, condensation reaction). Its core principle is to use the boiling point difference of azeotrope (such as the lowest azeotrope formed by organic matter and water), water is removed in the form of azeotrope by distillation, and then separated by condensation and liquid separation to realize water phase separation, and organic phase is returned to the reaction system, so as to promote the forward reaction and improve the yield of product.

[0003] However, the existing azeotropic distillation water separation system has many technical defects in actual application, which restricts the separation efficiency and operation stability: (1) Poor phase separation effect and low water separation precision: there is no structured separation component in the traditional liquid separation tank, and the gas-liquid mixture after gas phase condensation directly enters the liquid separation tank, which is easy to emulsify or stratify the organic phase (such as ester, benzene series) and water phase due to turbulent flow, and easy to carry organic phase when draining, causing loss of raw materials or decrease of product purity. Although some systems are provided with baffles, the angle and length of the baffles are not reasonably designed, and the liquid droplets carried by the gas phase cannot be effectively blocked.

[0004] (2) Poor controllability and inconvenient observation: the existing system lacks intuitive liquid level and phase interface observation device, and the operator cannot accurately judge the water phase accumulation amount, which often leads to "excessive water discharge (carrying organic phase)" or "insufficient water discharge (incomplete water separation)" due to misjudgment of water discharge time. Although some systems are equipped with liquid level meter, there is no auxiliary sight cup, and the liquid level reading error is large in poor light workshop environment, which further affects the operation accuracy.

[0005] (3) Insufficient reflux stability, easy to suck back: the traditional reflux pipeline is mostly designed as straight pipe, when the distillation system pressure fluctuates, the pressure difference between the liquid separation tank and the distillation kettle is easy to cause liquid suck back, which pollutes the raw materials or destroys the reaction balance; The control of reflux valve of some systems lags behind, and the reflux amount cannot be dynamically adjusted according to the distillation rate, which causes the organic phase to return not in time, affecting the reaction efficiency. SUMMARY

[0006] To address the problems in the prior art, this utility model provides an azeotropic distillation continuous water separation system suitable for azeotropic water separation of solvents with a specific gravity greater than water, such as dichloromethane, trichloromethane, dichloroethane, trichloroethane, chlorobenzene, and o-dichlorobenzene. The technical solution includes a distillation kettle, with a mixed gas outlet pipe at the top and the other end of the mixed gas outlet pipe connected to the top of the side wall of a separating tank. A condenser is located at the top of the separating tank, a first liquid outlet pipe is located at the top of the side wall of the separating tank, and a second liquid outlet pipe is located at the bottom of the separating tank.

[0007] In a preferred embodiment, the side wall of the separator is provided with a reflux pipe near the bottom, the other end of which is connected to the top of the distillation vessel, and a shut-off valve is provided on the reflux pipe.

[0008] In a preferred embodiment, the reflux pipe is a U-shaped pipe, with the pipe closer to the distillation vessel being higher than the pipe closer to the separator.

[0009] In a preferred embodiment, a level gauge is provided on the side wall of the separator.

[0010] In a preferred embodiment, the inner wall of the separator is provided with several layers of baffles, and adjacent baffles are staggered.

[0011] In a preferred embodiment, the top two layers of the baffles are inclined toward the center of the separator at an angle of 15°-30°, while the remaining baffles are installed horizontally.

[0012] In a preferred embodiment, the length of the baffle is greater than the radius of the separator.

[0013] In a preferred embodiment, a first sight glass is also provided on the side wall of the separating tank, and the first sight glass is connected in parallel between the separating tank and the first liquid outlet pipe.

[0014] In a preferred embodiment, the second liquid outlet pipe is provided with a second sight glass, and both the inlet and outlet of the second sight glass are equipped with shut-off valves.

[0015] The beneficial effects of this utility model are: (1) The multi-layered staggered baffles installed on the inner wall of the separator can effectively block the turbulence formed after the gas phase condenses, and reduce the emulsification of the organic phase and the aqueous phase; the uppermost baffle is inclined to the center at 15°-30°, which can guide the condensate to flow slowly along the baffle and promote droplet coalescence and stratification; the baffle length is greater than the radius of the separator, which can further extend the gas-liquid contact path and prevent unseparated droplets from directly entering the outlet pipe; (2) The liquid level gauge on the side wall of the separator can display the liquid level in the tank in real time. Together with the first sight cup and the second sight cup, the operator can intuitively observe the position of the organic phase-water phase interface and the liquid flow state: the first sight cup is connected in parallel between the separator and the first liquid outlet pipe, which makes it easy to judge whether the water phase discharge is mixed with organic phase; the second sight cup is located in the second liquid outlet pipe, which can accurately control the timing of organic phase discharge and avoid "excessive drainage" or "incomplete water separation"; (3) The reflux pipe adopts a U-shaped design, with the pipe near the distillation vessel higher than the pipe near the separator, which can form a liquid seal effect, effectively buffering system pressure fluctuations and preventing liquid in the separator from being drawn back to the distillation vessel due to pressure difference; the shut-off valve on the reflux pipe can dynamically adjust the reflux flow rate according to the distillation rate, ensuring that the organic phase is stably refluxed to the reaction system, maintaining azeotropic equilibrium, and reducing the decrease in reaction efficiency caused by reflux interruption. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the overall structure of this utility model.

[0017] In the diagram: 1. Distillation vessel; 2. Mixed gas outlet pipe; 3. Separator; 4. Condenser; 5. Reflux pipe; 6. First liquid outlet pipe; 7. Level gauge; 8. First sight glass; 9. Second liquid outlet pipe; 10. Second sight glass; 11. Baffle. Detailed Implementation

[0018] The present invention will now be further described with reference to the accompanying drawings and specific embodiments.

[0019] Example like Figure 1 The azeotropic distillation continuous water separation system shown includes a distillation vessel 1, a mixed gas outlet pipe 2 at the top of the distillation vessel 1, the other end of the mixed gas outlet pipe 2 being connected to the top of the side wall of the separating tank 3, a condenser 4 at the top of the separating tank 3, a first liquid outlet pipe 6 at the top of the side wall of the separating tank 3, and a second liquid outlet pipe 9 at the bottom of the separating tank 3.

[0020] The distillation vessel 1 heats the internal raw material to turn it into a gas. The gas goes from the mixed gas outlet pipe 2 to the inside of the separator 3, then rises to the condenser 4 to condense into a liquid and falls back into the separator 3. It settles and separates into layers in the separator 3. The light substance is then discharged through the first liquid outlet pipe 6, and the heavy substance is discharged through the second liquid outlet pipe 9.

[0021] Furthermore, the side wall of the separator 3 is provided with a reflux pipe 5 near the bottom, and the other end of the reflux pipe 5 is connected to the top of the distillation vessel 1. A shut-off valve is provided on the reflux pipe 5.

[0022] The heavy material in the separatory tank 3 returns to the distillation vessel 1 through the reflux pipe 5. The shut-off valve on the reflux pipe 5 is used to control whether the heavy material is allowed to return to the distillation vessel 1.

[0023] Furthermore, the reflux pipe 5 is a U-shaped pipe, with the pipe near the distillation vessel 1 being higher than the pipe near the separator 3.

[0024] Since the pipes near the distillation vessel 1 are higher than those near the separator 3, a liquid seal effect can be formed, which effectively buffers system pressure fluctuations and prevents liquid in the separator from being drawn back into the distillation vessel 1 due to pressure differences. This also prevents the unseparated mixture (which may contain a small amount of aqueous phase) in the separator from being quickly "sucked" into the distillation vessel, thus avoiding contamination of the reaction system or disruption of the azeotropic equilibrium.

[0025] Furthermore, a level gauge 7 is provided on the side wall of the liquid separator 3.

[0026] This facilitates observation of the liquid level in the separator 7.

[0027] Furthermore, the inner wall of the liquid separator 3 is provided with several layers of baffles 11, and adjacent baffles 11 are staggered.

[0028] Baffle 11 guides the condensate to flow slowly along the baffle, promotes droplet coalescence and stratification, prevents the condensate from falling directly into the separator 3 and forming turbulence, and reduces emulsification of the organic phase and the aqueous phase.

[0029] Furthermore, the top two layers of the baffles 11 are inclined toward the center of the liquid separator 3 at an angle of 15°-30°, while the remaining baffles 11 are installed horizontally.

[0030] The upper two baffles 11 cause the droplets to quickly gather, while the remaining baffles 11 promote the condensate to settle completely.

[0031] Furthermore, the length of the baffle 11 is greater than the radius of the separator 3.

[0032] This allows the droplets on baffle 11 to fall directly onto the lower baffle 11 instead of falling into the bottom of the separator 3, further preventing the formation of turbulence.

[0033] Furthermore, a first sight glass 8 is provided on the side wall of the liquid separator 3, and the first sight glass 8 is connected in parallel between the liquid separator 3 and the first liquid outlet pipe 6.

[0034] During water separation, ensure that the water phase height in the first viewing cup 8 is observed. When separating phases, the lowest liquid level of the upper water phase must not be lower than the third baffle. Observe the interface between the organic phase and the water phase through the first viewing cup 8.

[0035] Furthermore, the second liquid outlet pipe 9 is provided with a second sight glass 10, and both the inlet and outlet of the second sight glass 10 are provided with shut-off valves.

[0036] During the cleanup, the second viewing cup 10 will be used to observe the material drained from the separatory tank 3. The lower part is the organic solvent and the upper part is the aqueous solvent, thus achieving the separation of the solvent and the aqueous phase during the cleanup.

[0037] The above-described water separation system operates as follows: Under heating conditions, the material in the distillation vessel 1 forms an azeotropic mixture (containing organic matter and water). This mixture enters the separatory tank 3 through the mixture outlet pipe 2 at the top of the distillation vessel. Upon entering the separatory tank 3, the mixture is first condensed into a liquid mixture (containing organic and aqueous phases) by the condenser 4 at the top. As the liquid mixture falls, it is blocked by multiple layers of staggered baffles 11 on the inner wall of the separatory tank, causing the organic phase (higher density, lower layer) and the aqueous phase (lower density, upper layer) to initially separate. The organic phase in the separatory tank returns to the distillation vessel 1 through the reflux pipe 5 at the bottom of the side wall, while the aqueous phase is discharged through the first liquid outlet pipe 6. If excess organic phase needs to be collected, it can be discharged through the second liquid outlet pipe 9 and the second sight glass 10.

Claims

1. An azeotropic distillation continuous water separation system, comprising a distillation vessel (1), characterized in that, The top of the distillation vessel (1) is provided with a mixed gas outlet pipe (2), the other end of which is connected to the top of the side wall of the separator (3). The top of the separator (3) is provided with a condenser (4), the top of the side wall of the separator (3) is provided with a first liquid outlet pipe (6), and the bottom of the separator (3) is provided with a second liquid outlet pipe (9). The inner wall of the liquid separator (3) is provided with several layers of baffles (11), and the adjacent baffles (11) are staggered.

2. The azeotropic distillation continuous water separation system according to claim 1, characterized in that, The side wall of the separator (3) is provided with a reflux pipe (5) near the bottom. The other end of the reflux pipe (5) is connected to the top of the distillation vessel (1). A shut-off valve is provided on the reflux pipe (5).

3. The azeotropic distillation continuous water separation system according to claim 2, characterized in that, The reflux pipe (5) is a U-shaped pipe, with the pipe near the distillation vessel (1) being higher than the pipe near the separator (3).

4. The azeotropic distillation continuous water separation system according to claim 1, characterized in that, The liquid level gauge (7) is provided on the side wall of the liquid separator (3).

5. The azeotropic distillation continuous water separation system according to claim 1, characterized in that, The top two layers of the baffles (11) are inclined toward the center of the liquid separator (3) at an angle of 15°-30°, while the remaining baffles (11) are installed horizontally.

6. The azeotropic distillation continuous water separation system according to claim 1, characterized in that, The length of the baffle (11) is greater than the radius of the separator (3).

7. The azeotropic distillation continuous water separation system according to claim 1, characterized in that, The side wall of the liquid separator (3) is also provided with a first sight glass (8), which is connected in parallel between the liquid separator (3) and the first liquid outlet pipe (6).

8. The azeotropic distillation continuous water separation system according to claim 1, characterized in that, The second liquid outlet pipe (9) is provided with a second sight glass (10), and both the inlet and outlet of the second sight glass (10) are provided with shut-off valves.

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