Dioctyl terephthalate distillation system

Abstract

The utility model belongs to the technical field of separation devices, and particularly relates to a dioctyl terephthalate distillation system which comprises a distillation tower, a plurality of tower plates arranged in the distillation tower, a heat exchanger connected to the bottom of the distillation tower, a product storage tank connected to the top of the distillation tower and a stirring assembly arranged in the distillation tower, the stirring assembly comprises a stirring paddle and a spiral stirrer, the stirring paddle is located at the bottom of the distillation tower, a plurality of corrugated plates and a plurality of flow guide covers are arranged in the distillation tower, the corrugated plates are located above the flow guide covers, and the flow guide covers are located above the stirring paddle. According to the utility model, the space in the distillation tower is divided into three parts according to functions, and each section adopts a proper internal component, so that the optimization of the distillation effect is realized.

Description

TECHNICAL FIELD

[0001] The utility model belongs to the technical field of separation device, concretely relates to a distillation system for dioctyl terephthalate. BACKGROUND

[0002] In the industrial refining process of dioctyl terephthalate, a vacuum rectifying tower is usually used. The traditional rectifying tower mostly uses sieve plates or random packed fillers. When processing dioctyl terephthalate and other high-boiling, heat-sensitive materials, obvious shortcomings are exposed, such as large liquid holdup and long residence time. The sieve plates or random packed fillers have high liquid holdup, and the material stays in the high-temperature tower kettle and tower for too long, which easily leads to thermal decomposition, oxidation and coloring of dioctyl terephthalate, affecting the color and thermal stability of the product.

[0003] In addition, dioctyl terephthalate has poor flowability due to high viscosity, and it is difficult to form a uniform and rapidly updated liquid film on the smooth surface of the filler, which easily forms a channel flow or a dry zone, resulting in a significant reduction in the effective mass transfer area. Since the liquid film is thick and slow to update, the liquid film resistance that the gas phase components need to diffuse through is large, and the mass transfer coefficient is low. For the rectification of dioctyl terephthalate which needs to be operated at a relatively high vacuum, the increase in pressure drop will significantly increase the tower kettle temperature, and exacerbate thermal decomposition. UTILITY MODEL CONTENT

[0004] In view of the above shortcomings in the prior art, the utility model aims to solve the technical problem of providing a distillation system for dioctyl terephthalate, improving the mass transfer efficiency of the distillation process, reducing the residence time of the material, and realizing the step-by-step utilization of energy.

[0005] The utility model solves the technical problem by adopting the following technical scheme:

[0006] The distillation system for dioctyl terephthalate comprises a distillation tower, a plurality of tower plates arranged inside the distillation tower, a heat exchanger connected to the bottom of the distillation tower, a product storage tank connected to the top of the distillation tower, a stirring assembly arranged inside the distillation tower, the stirring assembly comprising a stirring paddle and a spiral stirrer, the stirring paddle being located at the bottom of the distillation tower, a plurality of corrugated plates and a plurality of fairings being arranged inside the distillation tower, the corrugated plates being located above the fairings, and the fairings being located above the stirring paddle.

[0007] Among them:

[0008] A vacuum pump is arranged between the distillation tower and the product storage tank, and a residual pipeline is arranged between the vacuum pump and the product storage tank.

[0009] One end of the heat exchanger is connected to the bottom of the distillation tower, and the other end is connected to the middle of the distillation tower.

[0010] A raw material inlet is arranged on the side of the distillation tower.

[0011] The spiral agitator is located above the stirring paddle, and the spiral agitator is connected with the stirring paddle through the stirring shaft.

[0012] The flow guide cover is arranged on the several trays inside the distillation tower, the tray is arranged on the inner wall of the distillation tower, and the tray is located outside the stirring shaft.

[0013] The flow guide cover comprises a cylindrical cover body, a funnel-shaped flow guide groove is arranged at the top of the cover body, and a liquid outlet hole is arranged at the bottom of the cover body.

[0014] The outer side of the tray is surrounded by a baffle, a liquid return channel is arranged on the side away from the inner wall of the distillation tower, the cross section of the liquid return channel is arranged in a shape of a Chinese character 'fang', and the height of the baffle is higher than the height of the top surface of the liquid return channel.

[0015] The top of the stirring assembly penetrates the distillation tower and is connected with a motor.

[0016] The distillation tower is externally provided with a heating jacket.

[0017] The utility model has the beneficial effect that:

[0018] The utility model divides the space inside the distillation tower into three parts according to functions, adopts suitable internal components in each part, stirs the crude dioctyl terephthalate to the maximum extent at the bottom of the distillation tower, improves the mass transfer area, can efficiently separate the evaporated dioctyl terephthalate through zoned heating in the middle part of the distillation tower, reduces the impurity carrying and realizes the rapid discharge of materials through material reflux and cyclone separation at the top of the distillation tower, optimizes the distillation effect, fundamentally reduces the residence time of dioctyl terephthalate in a high-temperature environment, greatly inhibits the thermal decomposition and coloring side reaction, and guarantees the high color stability and high thermal stability of the product.

[0019] The flow guide cover provides a larger mass transfer specific surface area and more uniform phase contact, each flow guide cover serves as a separate heating zone and cooperates with the distillation tower as a whole heating tower, has a higher theoretical plate number under the same tower height, improves the separation efficiency, especially after cooperating with the corrugated plate and the spiral agitator, facilitates the removal of trace heavy components with close boiling points, realizes the step-by-step utilization of energy inside the rectification system, and reduces the additional energy consumption required for preheating of raw materials. BRIEF DESCRIPTION OF DRAWINGS

[0020] Fig. 1 It is a structural schematic diagram of the utility model;

[0021] Fig. 2 It is a flow guide cover structural schematic diagram of the utility model;

[0022] Fig. 3 is a tower plate structure schematic diagram of the utility model;

[0023] In the figure: 1, distillation column; 2, heat exchanger; 3, product storage tank; 4, vacuum pump; 5, residual pipeline; 6, stirring paddle; 7, corrugated plate; 8, fairing; 9, tower plate; 10, stirring shaft; 11, spiral agitator; 12, raw material inlet; 101, heating jacket; 801, drainage groove; 802, liquid outlet hole; 803, cover body; 901, baffle; 902, liquid return channel. DETAILED DESCRIPTION

[0024] The embodiments of the utility model are further described below in combination with the drawings.

[0025] Example 1

[0026] As Figs. 1-3 shown, the utility model discloses a distillation system of dioctyl terephthalate, including distillation tower 1, the inside of distillation tower 1 is provided with several tower plates 9, and the bottom of distillation tower 1 is connected with heat exchanger 2, and the top of distillation tower 1 is connected with product storage tank 3, and the inside of distillation tower 1 is provided with stirring assembly, and the stirring assembly includes stirring paddle 6 and spiral agitator 11, and stirring paddle 6 is located at the bottom of distillation tower 1, and the inside of distillation tower 1 is provided with several corrugated plates 7 and several fairings 8, and corrugated plate 7 is located above fairing 8, and fairing 8 is located above stirring paddle 6.

[0027] Vacuum pump 4 is arranged between distillation tower 1 and product storage tank 3, and residual pipeline 5 is arranged between vacuum pump 4 and product storage tank 3.

[0028] One end of heat exchanger 2 is connected with the bottom of distillation tower 1, and the other end is connected with the middle part of distillation tower 1.

[0029] The side of distillation tower 1 is provided with raw material inlet 12.

[0030] Spiral agitator 11 is located above stirring paddle 6, and spiral agitator 11 is connected with stirring paddle 6 through stirring shaft 10, and spiral agitator 11 is arranged in cooperation with several corrugated plates 7.

[0031] Fairing 8 is arranged on several tower plates 9 in the inside of distillation tower 1, tower plate 9 is arranged on the inner wall of distillation tower 1, and tower plate 9 is located on the outside of stirring shaft 10.

[0032] Fairing 8 includes cylindrical cover body 803, funnel-shaped drainage groove 801 is arranged at the top of cover body 803, and liquid outlet hole 802 is formed in the bottom of cover body 803.

[0033] A baffle 901 is arranged around the outer side of the tray 9. A return liquid channel 902 is provided on the baffle 901 on the side away from the inner wall of the distillation column 1. The cross-section of the return liquid channel 902 is arranged in the shape of a U. The height of the baffle 901 is higher than the height of the top surface of the return liquid channel 902.

[0034] A motor is connected to the top of the stirring assembly, which runs through the distillation column 1.

[0035] A heating jacket 101 is installed on the outside of the distillation column 1.

[0036] Working principle and process:

[0037] After the crude dioctyl terephthalate obtained from the esterification reaction enters the distillation column 1, the external heating jacket 101 is turned on for heating. First, the lighter components with lower boiling points of the crude dioctyl terephthalate are discharged through the discharge pipe 5. The crude dioctyl terephthalate enters from the bottom tray 9 and flows to the bottom of the distillation column 1. While the bottom of the distillation column 1 is being heated, the motor is turned on to stir the agitator 6 to prevent the liquid at the bottom of the distillation column 1 from remaining stagnant for a long time and causing material denaturation. During distillation, the distillate evaporates as the temperature rises, adheres to the surface of the guide shroud 8, condenses and enters the inlet channel 801, and then flows out from the outlet hole 802 until the distillate in the tray 9 flows down along the return liquid channel 902. Each guide shroud... The evaporation and condensation processes within the distillation column 8 are mutually convective, causing the distilled material to evaporate upwards layer by layer. Other impurities with properties similar to dioctyl terephthalate are retained, and separate separation can effectively purify dioctyl terephthalate, ensuring that the impurities in the dioctyl terephthalate evaporated from the uppermost guide hood 8 are minimized. The evaporated material rises again and, upon contact with the corrugated plate 7, the evaporated material and other substances adhere to the corrugated plate 7. The spiral stirrer 11 rotates and disturbs the evaporated material, forming a cyclone airflow that causes the evaporated material to move upwards. The impurities in the evaporated material flow back down to the bottom of the distillation column 1 along the corrugated plate 7. After evaporation is completed, the impurities at the bottom of the column are discharged uniformly.

Claims

1. A distillation system for dioctyl terephthalate comprising a distillation column (1), characterized in that, The distillation tower (1) is internally provided with a plurality of trays (9), the distillation tower (1) is connected with a heat exchanger (2) at the bottom, the distillation tower (1) is connected with a product storage tank (3) at the top, the distillation tower (1) is internally provided with a stirring assembly, the stirring assembly comprises a stirring paddle (6) and a spiral stirrer (11), the stirring paddle (6) is located at the bottom of the distillation tower (1), the distillation tower (1) is internally provided with a plurality of corrugated plates (7) and a plurality of fairings (8), the corrugated plates (7) are located above the fairings (8), and the fairings (8) are located above the stirring paddle (6).

2. The dioctyl terephthalate distillation system of claim 1, wherein, A vacuum pump (4) is arranged between the distillation tower (1) and the product storage tank (3), and a residual pipeline (5) is arranged between the vacuum pump (4) and the product storage tank (3).

3. The dioctyl terephthalate distillation system of claim 1, wherein, One end of the heat exchanger (2) is connected with the bottom of the distillation tower (1), and the other end is connected with the middle part of the distillation tower (1).

4. The dioctyl terephthalate distillation system of claim 1, wherein, The distillation tower (1) is provided with a raw material inlet (12) on the side.

5. The dioctyl terephthalate distillation system of claim 1, wherein, The spiral stirrer (11) is located above the stirring paddle (6), the spiral stirrer (11) and the stirring paddle (6) are connected through a stirring shaft (10), and the spiral stirrer (11) is arranged in cooperation with the plurality of corrugated plates (7).

6. The dioctyl terephthalate distillation system of claim 1, wherein, The fairings (8) are arranged on the plurality of trays (9) in the distillation tower (1), the trays (9) are arranged on the inner wall of the distillation tower (1), and the trays (9) are located outside the stirring shaft (10).

7. The dioctyl terephthalate distillation system of claim 1, wherein, The fairing (8) comprises a cylindrical cover body (803), a funnel-shaped flow guide groove (801) is arranged at the top of the cover body (803), and a liquid outlet hole (802) is arranged at the bottom of the cover body (803).

8. The dioctyl terephthalate distillation system of claim 1, wherein, The outer side of the tray (9) is provided with a baffle (901), the baffle (901) away from the inner wall of the distillation tower (1) is provided with a liquid return channel (902), the cross section of the liquid return channel (902) is in the shape of a Chinese character, and the height of the baffle (901) is higher than the height of the top surface of the liquid return channel (902).

9. The dioctyl terephthalate distillation system of claim 1, wherein, The top of the stirring assembly penetrates the distillation tower (1) and is connected with a motor.

10. The dioctyl terephthalate distillation system of claim 1, wherein, The distillation tower (1) is externally provided with a heating jacket (101).

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