Crude DOTP purifying and refining device

Abstract

The utility model relates to the technical field of DOTP (dioctyl terephthalate) processing, and discloses a crude DOTP purifying and refining device which comprises a purifying kettle, an exhaust pipe and a lower hollow liquid collecting tray, the exhaust pipe and the lower hollow liquid collecting tray are fixed at two ends of the surface of the purifying kettle, a cooling sleeve is fixed between the exhaust pipe and the lower hollow liquid collecting tray, a plurality of vertical S-shaped cooling pipes are annularly arranged in the cooling sleeve at equal intervals in an array manner, and the vertical S-shaped cooling pipes are communicated with the purifying kettle. The top end of the vertical S-shaped cooling pipe extends into the exhaust pipe, and the bottom end of the vertical S-shaped cooling pipe extends into the lower hollow liquid collecting tray. By means of the design of the upper hollow gas collecting disc, high-temperature gas can be evenly distributed into the vertical S-shaped cooling pipes, the condensation efficiency can be remarkably improved through the parallel condensation mode, more gas can be condensed in a shorter time, backflow of uncondensed gas is reduced, when the gas passes through the vertical S-shaped cooling pipes, the flowing path is longer, and the gas flow rate is higher. Therefore, the heat exchange efficiency is improved, and the high heat transfer efficiency can be achieved under the low temperature difference.

Description

Technical Field

[0001] The utility model relates to the technical field of DOTP processing, in particular to a crude DOTP purification and refining device. Background Art

[0002] The processing and purification of crude dioctyl terephthalate is an important step to ensure its excellent performance and safety in plastic applications. The process mainly includes several key links: raw material preparation, esterification reaction, preliminary separation, distillation, decolorization, dehydration and packaging and storage. The selection of raw materials is crucial. The quality of n-octanol and phthalic acid directly affects the purity of the final product. Therefore, the raw materials must be strictly tested for quality to ensure that they meet the standards. Subsequently, n-octanol and phthalic acid are mixed by esterification at a temperature of 150°C to 200°C, and a catalyst is added to increase the reaction rate and promote the reaction to generate DOTP by removing the water produced in the reaction. After the reaction is completed, the unreacted raw materials and other by-products are removed by distillation. Then, the purity of DOTP is further improved by crude distillation and fine distillation steps. Crude distillation separates the main components and light impurities, while fine distillation improves the separation efficiency and ensures the high purity of the final product. At this stage, during the distillation and dehydration process, the high-temperature gas inside the purification kettle enters the cooler, causing the gas to condense and form the desired product. During this stage, the high-temperature gas inside the purification kettle is condensed in the cooler in the form of a single spiral tube. The design of the single spiral tube cooler makes the flow of the fluid in the tube relatively short, and the gas may not be able to fully exchange heat with the cooling medium when flowing in the pipeline. Due to the fast flow rate of the gas, at a certain temperature and pressure, part of the gas cannot be fully condensed in the cooler, resulting in the reflux of uncondensed gas, and with the passage of time, some areas in the spiral tube cause the cooling effect to decrease due to fluid retention or local overheating, resulting in ineffective condensation, affecting the collection amount and quality of the condensed product. Utility Model Content

[0003] The utility model aims to provide a crude DOTP purification and refining device, wherein an upper hollow gas collecting plate, a cooling jacket and a lower hollow liquid collecting plate which are isolated from each other are sequentially installed on the outer peripheral surface of a purification kettle from top to bottom, and the high-temperature gas generated by the purification kettle first enters the upper hollow gas collecting plate, and the upper hollow gas collecting plate evenly distributes the high-temperature gas to each vertical S-shaped cooling tube, and each vertical S-shaped cooling tube exchanges heat with the low-temperature coolant in the cooling jacket and condenses the high-temperature gas, thereby achieving the purpose of multi-gas path parallel condensation to solve the problems raised in the above-mentioned background technology.

[0004] To achieve the above-mentioned purpose, the utility model provides the following technical solutions: a crude DOTP purification and refining device, comprising a purification kettle and an exhaust pipe and a lower hollow liquid collecting tray fixed at both ends of the surface of the purification kettle, a cooling jacket is fixed between the exhaust pipe and the lower hollow liquid collecting tray, a plurality of vertical S-shaped cooling pipes are arranged in an annular array with equal spacing inside the cooling jacket, the top end of the vertical S-shaped cooling pipe extends to the inside of the exhaust pipe, and the bottom end of the vertical S-shaped cooling pipe extends to the inside of the lower hollow liquid collecting tray, an air inlet pipe is arranged on one side of the top of the purification kettle, and an air return component connected to the air inlet pipe is installed on one side of the outer wall of the lower hollow liquid collecting tray.

[0005] Preferably, a liquid inlet solenoid valve is installed on one side outer wall of the cooling jacket, and a liquid outlet solenoid valve is installed on the other side outer wall of the cooling jacket.

[0006] Preferably, a discharge pipe is installed on one side of the bottom end of the lower hollow liquid collecting tray, and a discharge solenoid valve is installed at the bottom end of the discharge pipe.

[0007] Preferably, the air return assembly includes a C-type air return pipe installed on the outer wall of one side of the lower hollow liquid collection tray, and a second solenoid valve installed on one end of the surface of the C-type air return pipe, and the top end of the C-type air return pipe is interconnected with the top end of the air inlet pipe.

[0008] Preferably, the vertical S-shaped cooling pipe includes an S-shaped heat exchange tube installed at the bottom end of the upper hollow gas collecting plate and a vertical pipe installed at the bottom end of the S-shaped heat exchange tube, and the bottom end of the vertical pipe extends to the interior of the lower hollow liquid collecting plate.

[0009] Preferably, the S-shaped heat exchange tube and riser are both made of aluminum alloy components.

[0010] Compared with the prior art, the beneficial effects of the utility model are as follows: the crude DOTP purification and refining device can evenly distribute high-temperature gas to multiple vertical S-shaped cooling tubes through the design of the upper hollow gas collecting plate, and the parallel condensation method can significantly improve the condensation efficiency, so that more gas can be condensed in a shorter time, and the reflux of uncondensed gas can be reduced, thereby ensuring the purity and yield of the final product. When the gas passes through the vertical S-shaped cooling tube, the flow path is longer, thereby improving the efficiency of heat exchange, and achieving higher heat transfer efficiency at a lower temperature difference, so that the high-temperature gas is quickly cooled and condensed into liquid. Moreover, by evenly distributing the gas to multiple vertical S-shaped cooling tubes, the temperature in each pipe can be kept relatively stable, ensuring the continuity of the condensation process, and ultimately improving the product quality of DOTP. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 This is a schematic diagram of the main cross-sectional structure of the utility model;

[0012] Figure 2The three-dimensional cross-sectional structure of the utility model is shown in FIG. Figure 1 ;

[0013] Figure 3 The three-dimensional cross-sectional structure of the utility model is shown in FIG. Figure 2 ;

[0014] Figure 4 The three-dimensional structure of the utility model is shown in FIG. Figure 1 ;

[0015] Figure 5 The three-dimensional structure of the utility model is shown in FIG. Figure 2 .

[0016] In the figure: 1, purification kettle; 101, air inlet pipe; 2, exhaust pipe; 3, upper hollow air collecting plate; 4, lower hollow liquid collecting plate; 5, cooling jacket; 501, liquid outlet solenoid valve; 502, liquid inlet solenoid valve; 6, material outlet solenoid valve; 7, air return assembly; 701, C-type air return pipe; 702, second solenoid valve; 8, vertical S-type cooling pipe; 801, S-type heat exchange pipe; 802, vertical pipe. DETAILED DESCRIPTION

[0017] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0018] See also Figure 1-5 The utility model provides an embodiment: a crude DOTP purification and refining device, comprising a purification kettle 1 and an exhaust pipe 2 and a lower hollow liquid collecting tray 4 fixed at both ends of the surface of the purification kettle 1, a discharge pipe is installed on one side of the bottom end of the lower hollow liquid collecting tray 4, and a discharge solenoid valve 6 is installed at the bottom end of the discharge pipe. The liquid product obtained by condensation can be directly discharged through the discharge solenoid valve 6 for subsequent use; a cooling jacket 5 is fixed between the exhaust pipe 2 and the lower hollow liquid collecting tray 4, and the staff can also install a solenoid valve at the end of the exhaust pipe 2 to control whether the high-temperature gas is discharged and control its discharge amount;

[0019] A plurality of vertical S-shaped cooling pipes 8 are arranged in an annular array with equal spacing inside the cooling jacket 5. The top end of the vertical S-shaped cooling pipe 8 extends to the inside of the exhaust pipe 2, and the bottom end of the vertical S-shaped cooling pipe 8 extends to the inside of the lower hollow liquid collecting pan 4. An air inlet pipe 101 is arranged on one side of the top of the purification kettle 1, and a return air component 7 connected to the air inlet pipe 101 is installed on one side of the outer wall of the lower hollow liquid collecting pan 4.

[0020] The cooling jacket 5 surrounds the outside of the vertical S-shaped cooling tube 8, and low-temperature coolant, usually water or other coolant, flows inside. The temperature of the coolant is usually lower than the condensation temperature of the gas, ensuring that the gas can effectively release heat and condense into liquid;

[0021] A liquid inlet solenoid valve 502 is installed on one side outer wall of the cooling jacket 5, and a liquid outlet solenoid valve 501 is installed on the other side outer wall of the cooling jacket 5. External coolant enters the cooling jacket 5 through the liquid inlet solenoid valve 502 and contacts the vertical S-shaped cooling pipe 8, and the coolant after heat exchange will be discharged through the liquid outlet solenoid valve 501, so that the coolant circulates. The cooling jacket 5 can effectively reduce the temperature of the high-temperature gas in the vertical S-shaped cooling pipe 8 and promote its condensation into liquid. Through rapid and uniform cooling, the presence of uncondensed gas can be reduced, ensuring the purity and quality of the final product;

[0022] The air return assembly 7 includes a C-type air return pipe 701 installed on the outer wall of one side of the lower hollow liquid collecting pan 4, and a second solenoid valve 702 installed on one end of the surface of the C-type air return pipe 701. The top end of the C-type air return pipe 701 is connected to the top end of the air inlet pipe 101. When the staff opens the second solenoid valve 702 and makes it normally open, the uncondensed gas in the lower hollow liquid collecting pan 4 will flow into the purification kettle 1 through the C-type air return pipe 701.

[0023] The vertical S-shaped cooling tube 8 includes an S-shaped heat exchange tube 801 installed at the bottom end of the upper hollow gas collecting plate 3 and a riser 802 installed at the bottom end of the S-shaped heat exchange tube 801. The bottom end of the riser 802 extends to the interior of the lower hollow liquid collecting plate 4. The S-shaped heat exchange tube 801 and the riser 802 are both made of aluminum alloy components. The high-temperature gas first enters the S-shaped heat exchange tube 801. The S-shaped heat exchange tube 801 increases the turbulence of the fluid flow. This turbulence phenomenon can accelerate the transfer of heat, so that the coolant can quickly absorb the heat and take it away. The setting of the riser 802 can make the liquid product obtained by condensation enter the lower hollow liquid collecting plate 4 more quickly.

[0024] When the embodiment of the present application is in use, first, the purification kettle 1 is the place where the high-temperature gas is generated by the reaction. During the reaction process, the reactants undergo esterification reaction under the action of high temperature and catalyst, and the generated gas contains DOTP, unreacted raw materials and other by-products. The temperature of these high-temperature gases is usually between 150°C and 200°C, and contains steam and volatile components. After the reaction is completed, the generated high-temperature gas is guided out of the purification kettle 1 through the exhaust pipe 2 and directly enters the upper hollow gas collecting plate 3. The end of the exhaust pipe 2 is connected to the upper hollow gas collecting plate 3 to ensure that the gas can be evenly distributed to each vertical S-shaped cooling tube 8. The upper hollow gas collecting plate 3 receives the high-temperature gas from the exhaust pipe 2 and can evenly distribute the gas to the multiple cooling tubes below. There are vertical S-shaped cooling tubes 8. At this time, each vertical S-shaped cooling tube 8 can receive a certain amount of gas. In each vertical S-shaped cooling tube 8, the high-temperature gas exchanges heat with the low-temperature coolant flowing in the cooling jacket 5. Due to the design of the S-shaped tube, the flow path of the gas in the tube is longer, which increases the contact and heat exchange time between the gas and the coolant, thereby improving the heat exchange efficiency. The condensed liquid will flow into the lower hollow liquid collecting tray 4 along the vertical S-shaped cooling tube 8. The lower hollow liquid collecting tray 4 allows the condensed liquid to be effectively collected and prevents the low-temperature gas from entering the vertical S-shaped cooling tube 8 again. During the condensation process, the gas that has not been condensed will flow back to the purification kettle 1 through the return gas component 7, thereby forming a closed pipeline system.

Claims

1. A crude DOTP purification and refining device, characterized in that: The invention comprises a purification kettle (1) and an exhaust pipe (2) and a lower hollow liquid collecting tray (4) fixed at both ends of the surface of the purification kettle (1); a cooling jacket (5) is fixed between the exhaust pipe (2) and the lower hollow liquid collecting tray (4); a plurality of vertical S-shaped cooling pipes (8) are arranged in an annular array with equal spacing inside the cooling jacket (5); the top end of the vertical S-shaped cooling pipe (8) extends to the inside of the exhaust pipe (2); the bottom end of the vertical S-shaped cooling pipe (8) extends to the inside of the lower hollow liquid collecting tray (4); an air inlet pipe (101) is arranged on one side of the top end of the purification kettle (1); and a return air component (7) connected to the air inlet pipe (101) is installed on one side of the outer wall of the lower hollow liquid collecting tray (4).

2. A crude DOTP purification and refining device according to claim 1, characterized in that: A liquid inlet solenoid valve (502) is installed on one side outer wall of the cooling jacket (5), and a liquid outlet solenoid valve (501) is installed on the other side outer wall of the cooling jacket (5).

3. A crude DOTP purification and refining device according to claim 1, characterized in that: A discharge pipe is installed on one side of the bottom end of the lower hollow liquid collecting tray (4), and a discharge solenoid valve (6) is installed at the bottom end of the discharge pipe.

4. A crude DOTP purification and refining device according to claim 1, characterized in that: The air return assembly (7) comprises a C-shaped air return pipe (701) mounted on an outer wall of one side of the lower hollow liquid collecting tray (4), and a second solenoid valve (702) mounted on one end of the surface of the C-shaped air return pipe (701), wherein the top end of the C-shaped air return pipe (701) is connected to the top end of the air inlet pipe (101).

5. A crude DOTP purification and refining device according to claim 1, characterized in that: The vertical S-shaped cooling pipe (8) comprises an S-shaped heat exchange pipe (801) installed at the bottom end of the upper hollow gas collecting plate (3) and a vertical pipe (802) installed at the bottom end of the S-shaped heat exchange pipe (801), wherein the bottom end of the vertical pipe (802) extends to the interior of the lower hollow liquid collecting plate (4).

6. A crude DOTP purification and refining device according to claim 5, characterized in that: The S-shaped heat exchange tube (801) and the vertical tube (802) are both made of aluminum alloy components.

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