A tower-type esterification reactor for the preparation of pentaerythritol oleate

Abstract

This application relates to the field of esterification production process equipment technology, and particularly to a tower-type esterification reactor for the preparation of pentaerythritol oleate, comprising: a tower body and multiple layers of trays distributed within the tower body; the tower body includes a high-temperature transesterification reaction distillation section with parallel gas flow and series liquid flow between the trays; in the high-temperature transesterification reaction distillation section, the liquid phase fluid flows sequentially from top to bottom through each tray, finally falling into the reactor bottom; after the gas phase fluid evaporates from each tray, it flows through a gas phase flow channel to a condenser for condensation, and the condensate is dehydrated or separated, with the organic matter returning to the tower-type reactor and the water discharged; the tower body is also equipped with a feed inlet, a discharge outlet, and a steam outlet. The tower-type esterification reactor for the preparation of pentaerythritol oleate provided in this application solves the problems of poor continuity of esterification reaction, low reaction efficiency, poor esterification rate, and poor material adaptability existing in the prior art.

Description

Technical Field

[0001] This application relates to the field of esterification production process equipment technology, and in particular to a tower-type esterification reactor for the preparation of pentaerythritol oleate. Background Technology

[0002] Pentaerythritol oleate has wide applications in various fields, including as an anti-wear and water-resistant modifier in lubricants, a lubricant and release agent in plastics processing, and an additive in textiles and coatings. China is one of the world's major producers and exporters of pentaerythritol oleate. With the growth in market demand and increased production capacity, exports are expected to continue to increase. As global emphasis on environmental protection and sustainable development grows, the market demand for pentaerythritol oleate continues to rise due to its excellent performance and environmentally friendly properties.

[0003] The synthesis of pentaerythritol oleate involves the esterification of pentaerythritol with oleic acid. The generated water must be continuously evaporated to ensure complete esterification. During production, strict control of the mass transfer interface area, reaction pressure, residence time, and temperature is crucial to ensure timely removal of the generated water, allowing the reaction to proceed in the forward direction and achieving a high esterification rate. Furthermore, the material temperature must be controlled during processing to prevent excessively high temperatures that could lead to numerous side reactions and a darker product color. Optimization of the process and achievement of the required technical conditions directly impact production costs and efficiency, placing high demands on the process flow and internal structure of the preparation equipment.

[0004] The transesterification method for producing pentaerythritol oleate has the advantage of easy control over the reaction process and product quality indicators. However, it requires the prior preparation of a low-boiling-point alcohol oleate, followed by transesterification with pentaerythritol. The low-boiling-point alcohol produced during transesterification is then condensed and recovered. This two-step esterification transesterification method is time-consuming and energy-intensive, resulting in multiple esterification reaction steps, poor continuity, low production efficiency, and high energy consumption. Furthermore, the color of the final product is also affected.

[0005] Esterification reactions are generally carried out using traditional batch reactors. However, because the materials are in a completely mixed state, the time to reach reaction equilibrium is very long, and the purity of the final product is not high due to limitations in the initial material composition (e.g., an excess of a certain reactant). In addition, the mass transfer interface of the batch reactor is limited by the diameter of the vessel, making it difficult to remove water from the esterification product in a timely and sufficient manner even with thorough stirring, which further delays the formation efficiency of the desired esterification product.

[0006] To improve the efficiency of esterification reactions, researchers have developed reactive distillation processes based on traditional distillation column equipment. By leveraging the differences in liquid phase composition resulting from gas-liquid equilibrium on different trays, the reaction and separation processes can be coupled, and catalysts can be incorporated into the packing material to enhance reaction efficiency. However, this traditional column reactor is limited by the volatility of the materials, making it suitable only for esterification reactions of low-boiling-point materials. Otherwise, excessively high reactor temperatures will lead to product quality deterioration, while excessively high vacuum will limit the pressure drop (further restricting the number of trays or packing height), and process control is difficult to maintain stably. Furthermore, in traditional column reactors, the product water generated during esterification passes through each tray in stages, which inhibits the esterification reaction in the corresponding regions, reducing product formation efficiency. Summary of the Invention

[0007] This application provides a tower-type esterification reactor for the preparation of pentaerythritol oleate, in order to solve the problems of poor continuity of esterification reaction, low reaction efficiency, poor esterification rate and material adaptability in the prior art.

[0008] To address the aforementioned technical problems, this application provides a tower-type esterification reactor for the preparation of pentaerythritol oleate, comprising: a tower body and multiple layers of trays distributed within the tower body; the tower body includes a high-temperature transesterification reaction distillation section with parallel gas flow and series liquid flow between the trays; in the high-temperature transesterification reaction distillation section, the liquid phase fluid flows sequentially from top to bottom through each tray, and finally falls to the reactor bottom; after the gas phase fluid evaporates from each tray, it passes through a gas phase flow channel to a condenser for condensation, and after dehydration or water separation, the organic matter returns to the tower reactor, and the water is discharged; the tower body is also provided with a feed inlet, a discharge outlet, and a steam outlet.

[0009] In some exemplary embodiments, the column body further includes a medium-temperature esterification reaction distillation section with countercurrent series flow of gas and liquid phases between each tray, located above the high-temperature transesterification reaction distillation section. In the medium-temperature esterification reaction distillation section, the liquid phase flows through the trays sequentially from top to bottom, finally falling into the uppermost tray of the high-temperature transesterification reaction distillation section; the gas phase flows through each tray sequentially from bottom to top, then converges at the top of the reactor column, flows through the gas phase flow channel to the condenser for condensation, and after dehydration or water separation, the organic matter is returned to the reactor, and the water is discharged; in the high-temperature transesterification reaction distillation section, the gas phase fluid leaves each tray and directly enters the medium-temperature esterification reaction distillation section.

[0010] In some exemplary embodiments, the trays of the distillation section of the medium-temperature esterification reaction are provided with multiple sieves and bubble caps; a riser is provided inside the bubble cap, and a toothed slit is provided at the bottom of the bubble cap; the gas phase rises from the riser and escapes from the liquid layer through the toothed slit at the bottom of the bubble cap via the cyclic passage between the bubble cap and the riser; the liquid phase passes through the sieves, so that the liquid falls to the next layer. The feed rate is greater than the liquid descent rate, generating countercurrent, which makes the reaction more complete.

[0011] In some exemplary embodiments, the trays of the high-temperature transesterification distillation section are columnar structures or shallow tray structures with overflow ports.

[0012] In some exemplary embodiments, the gas phase channels and liquid phase channels of the trays in the high-temperature transesterification distillation section are staggered.

[0013] In some exemplary embodiments, the liquid phase fluid is a mixture of pentaerythritol, a small molecule alcohol, and oleic acid, wherein the ratio of pentaerythritol to oleic acid is 4 to 4.2:1; the small molecule alcohol includes one or more of methanol, ethanol, butanol, isoamyl alcohol, and diisoamyl alcohol.

[0014] In some exemplary embodiments, the tray is a composite tray composed of packing and plates; the packing is random packing or structured packing loaded with catalyst.

[0015] In some exemplary embodiments, the catalyst-supported random packing material includes one or more of the following: solid acid supported on a particulate support, stannous oxalate crystals, and cation exchange resin.

[0016] In some exemplary embodiments, the feed inlet and the exhaust outlet are located at the top of the tower. The oleic acid and pentaerythritol reactants, which are mixed in proportion, enter the top of the tower through the feed inlet and then disperse onto the trays inside the tower. The exhaust outlet is connected to the condenser. The discharge outlet is located at the bottom of the tower and is used to discharge pentaerythritol oleate. A filter mechanism is installed in the pipeline of the discharge outlet to remove solid particulate impurities.

[0017] In some exemplary embodiments, at least one tray is equipped with a heater to control the internal temperature of the esterification reactor by heating the tray and evaporating the material.

[0018] The technical solution provided in this application has at least the following advantages:

[0019] This application provides a tower-type esterification reactor for the preparation of pentaerythritol oleate, comprising: a tower body and multiple layers of trays distributed within the tower body; the tower body includes a high-temperature transesterification reaction distillation section with parallel gas flow and series liquid flow between the trays; in the high-temperature transesterification reaction distillation section, the liquid phase fluid flows sequentially from top to bottom through each tray and finally falls to the reactor bottom; after the gas phase fluid evaporates from each tray, it passes through a gas phase flow channel to a condenser for condensation, and after dehydration or water separation, the organic matter returns to the tower reactor, and the water is discharged; the tower body is also provided with a feed inlet, a discharge outlet, and a steam outlet.

[0020] The tower-type esterification reactor for the preparation of pentaerythritol oleate provided in this application adopts a multi-layered, stepped composite plate tower structure, which can achieve coupling of material reaction and separation phases. When only a high-temperature transesterification reaction distillation section is available, vacuum operation is preferred. The trays of the high-temperature transesterification reaction distillation section are columnar structures or shallow pan structures with overflow ports, which can effectively control the hydraulic residence time of the material by adjusting the liquid holdup and operating conditions, thereby achieving continuous production of pentaerythritol oleate. The reactor provided in this application has a semi-series-semi-parallel structure (liquid phase flows through the trays in series, and vapor phase leaves the trays in parallel) high-temperature transesterification reaction distillation section, which can form a large surface area shallow / thin liquid layer. While the stepped reaction occurs in each composite plate, it ensures the timely and effective removal of small molecule volatile components at the end of the esterification reaction. Attached Figure Description

[0021] One or more embodiments are illustrated by way of example with reference to the accompanying drawings. These illustrations do not constitute a limitation on the embodiments, and unless otherwise stated, the figures in the drawings are not to be limited by scale.

[0022] Figure 1 This is a schematic diagram of a tower-type esterification reactor for the preparation of pentaerythritol oleate, provided as an embodiment of this application.

[0023] Figure 2 This is a schematic diagram of the structure of the tray in the distillation section of the intermediate-temperature esterification reaction provided in an embodiment of this application.

[0024] Figure 3 This is a schematic diagram of the structure of the tray of the high-temperature transesterification reaction distillation section provided in an embodiment of this application.

[0025] Figure 4 This is a schematic diagram of a composite tower plate with an overflow port provided in an embodiment of this application.

[0026] Figure 5 This is a schematic diagram of a composite tray with an overflow port provided in an embodiment of this application.

[0027] Figure 6 This is a top view of a composite tray with an overflow port and a columnar structure provided in an embodiment of this application.

[0028] Figure 7 This is a top view of a composite tray with a shallow pan structure and an overflow port, provided in an embodiment of this application.

[0029] In the figure, the following labels are used: 1. Feed inlet; 2. Medium-temperature esterification reaction distillation section; 21. Bubble cap plate; 211. Bubble cap; 212. Sieve hole; 22. Packing material; 3. High-temperature transesterification reaction distillation section; 31. Composite tray with columnar structure and overflow port; 32. Composite tray with shallow pan structure and overflow port; 4. Exhaust port; 5. Discharge port. Detailed Implementation

[0030] As can be seen from the background technology, existing batch reactors have problems such as low mass transfer efficiency, limited reaction efficiency, and inability to produce continuously; existing tower reactors have problems such as difficulty in being used for high-temperature materials and the product water passing through the reaction separation zone layer by layer, affecting the reaction efficiency.

[0031] To address the aforementioned technical problems, this application provides a tower-type esterification reactor for the preparation of pentaerythritol oleate, comprising: a tower body and multiple layers of trays distributed within the tower body; the tower body includes a high-temperature transesterification reaction distillation section with parallel gas flow and series liquid flow between the trays; in the high-temperature transesterification reaction distillation section, the liquid phase fluid flows sequentially from top to bottom through each tray, finally falling into the reactor bottom; after the gas phase fluid evaporates from each tray, it flows through a gas phase flow channel to a condenser for condensation, and the condensate is dehydrated / separated, with the organic matter returning to the tower reactor and the water discharged; the tower body is also equipped with a feed inlet, a discharge outlet, and a steam outlet. This application provides a tower-type esterification reactor for the preparation of pentaerythritol oleate to solve the problems of poor continuity of the esterification reaction, low reaction efficiency, poor esterification rate, and poor material adaptability in the prior art.

[0032] The embodiments of this application will now be described in detail with reference to the accompanying drawings. However, those skilled in the art will understand that many technical details have been provided in the embodiments of this application to facilitate a better understanding of the application. However, the technical solutions claimed in this application can be implemented even without these technical details and various variations and modifications based on the following embodiments.

[0033] See Figure 1This application provides a tower-type esterification reactor for the preparation of pentaerythritol oleate, comprising: a tower body and multiple layers of trays distributed within the tower body; the tower body includes a high-temperature transesterification reaction distillation section 3 with parallel gas flow and series liquid flow between the trays; in the high-temperature transesterification reaction distillation section 3, the liquid phase fluid flows sequentially from top to bottom through each tray and finally falls into the reactor bottom; after the gas phase fluid evaporates from each tray, it passes through the gas phase flow channel to the condenser for condensation, and after dehydration / water separation, the organic matter is returned to the tower reactor and the water is discharged; the tower body is also provided with a feed inlet 1, a steam outlet 4, and a discharge outlet 5.

[0034] In some embodiments, the column body further includes a medium-temperature esterification reaction distillation section 2 with countercurrent series flow of gas and liquid phases between each tray. The medium-temperature esterification reaction distillation section 2 is located above the high-temperature transesterification reaction distillation section 3. In the medium-temperature esterification reaction distillation section 2, the liquid phase passes through the trays in series from top to bottom and finally falls into the uppermost tray of the high-temperature transesterification reaction distillation section 3. The gas phase passes through each tray in series from bottom to top and then converges at the top of the reactor column. It then flows through the gas phase flow channel to the condenser for condensation. After dehydration or water separation, the organic matter is returned to the reactor and the water is discharged.

[0035] It should be noted that the esterification reactor column of this application may omit the intermediate-temperature esterification reaction rectification section 2 and only include the high-temperature transesterification reaction distillation section 3. When the intermediate-temperature esterification reaction rectification section 2 is omitted, the gaseous fluid in the high-temperature transesterification reaction distillation section 3 evaporates from each tray and flows through the gas phase flow channel to the condenser for condensation. After dehydration / water separation, the organic matter is returned to the tower reactor, and the water is discharged.

[0036] When a medium-temperature esterification reaction rectification section 2 is set up in the esterification reactor column, the gaseous fluid leaves each stage of the tray and directly enters the medium-temperature esterification reaction rectification section 2 in the high-temperature transesterification reaction distillation section 3. The tower-type esterification reactor of this application can be carried out under pressurized, atmospheric, or vacuum conditions. When only the high-temperature transesterification reaction distillation section is available, vacuum operation is preferred.

[0037] like Figure 2 As shown, in some embodiments, the tray (which may be called bubble cap tray 21) of the medium-temperature esterification reaction distillation section 2 is provided with multiple sieve holes 212 and bubble caps 211; a riser pipe is provided inside the bubble cap 211, and a toothed slit is opened at the bottom of the bubble cap 211; the gas phase rises from the riser pipe, escapes from the liquid layer through the cyclic passage between the bubble cap 211 and the riser pipe, and exits through the toothed slit at the bottom of the bubble cap 211; the liquid phase passes through the sieve holes 212, so that the liquid falls to the next layer. The feed rate is greater than the liquid falling rate, generating countercurrent, which makes the reaction more complete.

[0038] In some embodiments, the trays of the high-temperature transesterification distillation section 3 are columnar structures or shallow dish structures with overflow ports.

[0039] like Figure 3 As shown, in some embodiments, the gas phase channels and liquid phase channels of the trays in the high-temperature transesterification distillation section 3 are staggered.

[0040] In some embodiments, the liquid phase fluid is a mixture of pentaerythritol, a small molecule alcohol, and oleic acid, wherein the ratio of pentaerythritol to oleic acid is 4 to 4.2:1; the small molecule alcohol includes one or more of methanol, ethanol, butanol, isoamyl alcohol, and diisoamyl alcohol.

[0041] Small molecule alcohols and water are characterized by low boiling points and high volatility, while pentaerythritol, oleic acid, and oleic acid esters all have high boiling points. When the content of small molecule alcohols and water is high, the components can be separated by distillation; while when the content of small molecule alcohols and water is low, they can be removed from pentaerythritol esters in a timely and efficient manner by distillation.

[0042] In some embodiments, the trays are composite trays composed of packing and plates; the packing is either random packing or structured packing loaded with a catalyst, preferably random packing. The internal structure of the distillation section of the intermediate-temperature esterification reaction adopts the form of conventional tower equipment, while liquid distribution components are provided between the trays of the high-temperature transesterification reaction distillation section.

[0043] To meet specific production conditions and process requirements, the liquid holdup of the composite tray of packing + plate can be controlled by adjusting the equipment structure and size during the equipment design phase; during the operation phase, the hydraulic residence time of the fluid flowing through the composite tray can be controlled by controlling the operating conditions.

[0044] In some embodiments, the catalyst-supported random packing material includes one or more of a solid acid supported on a particulate support, stannous oxalate crystals, and cation exchange resin. The particulate matter or crystalline particles of the catalyst-supported material can be formed into random or structured packing materials through coating or bonding.

[0045] In some embodiments, the feed inlet and the exhaust outlet are located at the top of the tower. The oleic acid and pentaerythritol reactants, which are mixed in proportion, enter the top of the tower through the feed inlet and then disperse onto the trays inside the tower. The exhaust outlet is connected to the condenser. The discharge outlet is located at the bottom of the tower and is used to discharge pentaerythritol oleate. A filter mechanism is installed in the pipeline of the discharge outlet to remove solid particulate impurities.

[0046] It should be noted that the tower-type esterification reactor is also equipped with instrument ports, which are located on the trays. The oleic acid and pentaerythritol reactants, mixed in proportion, enter the top of the tower through the feed line and then disperse onto the composite plate inside the tower. Small molecule alcohols can enter the tower from the top in liquid form along with the mixture of oleic acid and pentaerythritol, or they can enter the tower from the bottom or middle of the medium-temperature esterification reaction rectification section in vapor form.

[0047] In the intermediate-temperature esterification reaction distillation section, the rising vapor phase is condensed by a condenser, and the condensate is dehydrated / separated, with the organic matter returned to the tower reactor and the water discharged from the system. In the high-temperature transesterification reaction distillation section, the gaseous fluid evaporates in parallel from each tray. The large surface area of ​​the shallow / thin liquid layer provided by the multi-layer composite trays improves the removal rate of by-product water and small molecule volatile components.

[0048] The condensate obtained from the condenser, after dehydration treatment, separates low-boiling-point alcohols and other organic components that can be recycled as small-molecule alcohol materials, reducing material consumption and the generation of waste.

[0049] In some embodiments, at least one tray is equipped with a heater to control the internal temperature of the esterification reactor by heating the tray and evaporating the material. When the material is in a non-boiling state, the evaporation will be slow, and the process is mainly in a temperature-adjusting and heat-preserving state.

[0050] The tower-type esterification reactor for the preparation of pentaerythritol oleate provided in this application will be described in detail below through specific embodiments.

[0051] Example 1

[0052] Reference Figure 1This application provides a tower-type esterification reactor for the preparation of pentaerythritol oleate to improve the completeness of the reaction. The esterification reactor includes a feed inlet 1; a medium-temperature esterification reaction distillation section 2 in a catalytic reaction tower; a high-temperature transesterification reaction distillation section 3 in a catalytic reaction tower; a steam outlet 4; and a discharge outlet 5. The feed inlet 1 includes an oleic acid feed inlet, a low-boiling-point alcohol reactant feed inlet, and a pentaerythritol feed inlet. The reactants are fed through the esterification reaction feed pipe, and a certain proportion of oleic acid and low-boiling-point alcohol reactants are pre-mixed through pretreatment. The raw materials are dispersed from the top of the tower through coils onto a composite tray inside the tower cavity. The packing material loaded with catalyst forms an immobilized packing material placed on the reactor tray to carry out the esterification reaction. One or more trays inside the tower-type esterification reactor are equipped with heaters, and the internal temperature of the esterification reactor can be controlled through the instrument port structure at the tray. The intermediate-temperature esterification distillation section 2 of the catalytic reaction tower is equipped with one or more composite trays (reaction layers) and packing 22, preferably bubble cap trays 21; the high-temperature ester exchange distillation section 3 of the catalytic reaction tower is equipped with one or more composite trays (reaction layers) and packing 22, the composite trays can be columnar structures with overflow ports or shallow dish structures, such as... Figure 4 and Figure 5 As shown, the composite plate is a columnar composite tower plate 31 with an overflow port or a shallow tray composite tower plate 32 with an overflow port; the exhaust port 4 of the esterification reaction tower is connected to the condenser, and the bottom of the tower esterification reactor is provided with a discharge port 5 for discharging pentaerythritol oleate to the outside. The discharge port pipeline is equipped with a filter mechanism for removing solid particulate impurities.

[0053] Example 2

[0054] This application provides a tower-type esterification reactor for the preparation of pentaerythritol oleate. Compared with the prior art, the trays in its reactor are composite trays consisting of packing material and plates. (Refer to...) Figure 2The trays in the intermediate-temperature esterification reaction distillation section 2 can have a sieve hole 212 and bubble cap 211 structure, preferably a bubble cap plate 21. Inside the bubble cap is a riser pipe. The gas phase rises through the riser pipe and escapes from the liquid layer through the slits at the bottom of the bubble cap 211 via the cyclic passage between the bubble cap 211 and the riser pipe. The liquid phase passes through the sieve hole 212, causing the liquid to fall to the next layer. The feed rate is greater than the liquid descent rate, generating countercurrent flow, making the reaction more complete. This product is commercially available. The bubble cap 211 tray has a large specific surface area, providing sufficient gas-liquid contact surface, which is a key factor in the mass transfer process, effectively improving mass and heat transfer. The size and number of bubble caps are designed according to the type of packing material in the column and the requirements of the separated system to ensure uniform gas-liquid distribution, avoiding excessive concentration or dead zones that could cause liquid blockage. It also reduces direct collisions between gas and liquid, preventing surface adhesion. The presence of bubble cap 211 reduces the resistance of gas and liquid passing through the packing, saving power consumption and reducing energy consumption, thereby improving mass transfer efficiency and resulting in higher tray efficiency. Bubble cap trays have good production capacity and can meet the needs of large-scale production.

[0055] Example 3

[0056] The trays in distillation section 3 of the high-temperature transesterification reaction can be columnar or shallow dish structures with overflow outlets. (Refer to...) Figure 4 and Figure 5 The baffles of the composite tray 31 with an overflow outlet (columnar structure) or the composite tray 32 with an overflow outlet (shallow dish structure) serve as gas-liquid phase channels. Rising gas in the tower passes through the tray and enters the upper packing layer and then the next layer. The gas phase is evenly distributed with low resistance, facilitating the placement of liquid distribution orifices. The total area of ​​this columnar gas channel occupies 15% of the tower cross-section. The cross-section of this columnar gas channel can be circular or rectangular. Circular gas channels typically have a diameter of 200mm–300mm, while rectangular gas channels usually have a larger cross-section than circular ones. The height of the baffles in the columnar or shallow dish structure can be determined as needed, but the standard height is 250mm. The high liquid level should be 25mm–50mm below the upper edge of the baffle. Operational flexibility depends on the high and low liquid levels. (Refer to...) Figure 6 and Figure 7 The columnar or shallow tray structure is installed in a top view, and the gas-liquid phase channels of the upper and lower trays are distributed in a staggered manner, symmetrical about the axis on the plane.

[0057] Example 4

[0058] The equipment system can operate under pressurized, atmospheric, or vacuum conditions. Vacuum operation is preferred when only the high-temperature transesterification distillation section 3 is present. There are two scenarios: One is that the composite plate can be a columnar structure with an overflow port. During vacuuming, in the high-temperature transesterification distillation section 3, the rising gas phase passes through the central pores, sequentially through each tray from bottom to top. The gaseous fluid evaporates in parallel from each tray, while the liquid phase passes through the trays sequentially from top to bottom. Through the columnar structure tray with overflow ports, the liquid phase flows to the next layer from the edge baffles of the pores. The gas phase then flows through the pores to the condenser for condensation. After dehydration / water separation, the organic matter returns to the tower reactor, and the water is discharged. Another scenario is that the composite plate can be a disc-shaped structure with an overflow port, as described above. Figure 3 During vacuuming, in the high-temperature transesterification distillation section, the rising gas phase passes through the side gaps, sequentially from bottom to top through each tray. The gaseous fluid evaporates in parallel from each tray, while the liquid phase passes through the trays in series from top to bottom. Through a shallow tray structure with overflow outlets, the liquid phase flows down to the next tray via baffles. The shallow tray or columnar structure of the composite tray allows for effective control of the material's hydraulic residence time by adjusting the liquid holdup and operating conditions, adapting to different production needs and enabling continuous production of pentaerythritol oleate.

[0059] Example 5

[0060] Reference Figure 1 In the intermediate-temperature esterification reaction distillation section 2, the gas and liquid phases flow counter-currently in series between each tray. The liquid phase passes through the trays sequentially from top to bottom, finally settling on the top tray of the high-temperature esterification reaction distillation section 3. The gas phase, on the other hand, passes through each tray sequentially from bottom to top, then converges at the top of the reactor column. It then flows through the exhaust port 4 to the condenser for condensation. After dehydration / water separation, the condensate returns the organic matter to the tower reactor, while the water is discharged. (Reference) Figure 4 and Figure 5 In the high-temperature transesterification distillation section, the various trays exhibit parallel gas-phase flow and series liquid-phase flow. The liquid fluid flows sequentially from top to bottom through each tray, eventually settling in the bottom of the column. The gas-phase fluid flows in parallel, exiting each tray and directly entering the medium-temperature esterification distillation section. The large surface area of ​​the shallow / thin liquid layers created by the multi-layer composite trays improves the removal rate of byproducts such as water and small-molecule volatile components.

[0061] The condensate obtained from the condenser, after dehydration treatment, separates low-boiling-point alcohols and other organic components that can be recycled as small-molecule alcohol materials, reducing material consumption and the generation of waste.

[0062] Based on the above technical solutions, this application provides a tower-type esterification reactor for the preparation of pentaerythritol oleate, comprising: a tower body and multiple layers of trays distributed within the tower body; the tower body includes a high-temperature transesterification reaction distillation section with parallel gas flow and series liquid flow between each layer of trays; in the high-temperature transesterification reaction distillation section, the liquid phase fluid flows sequentially from top to bottom through each layer of trays and finally falls into the reactor bottom; the gas phase fluid leaves each layer of trays and directly enters the medium-temperature esterification reaction rectification section; the tower body is also provided with a feed inlet, a discharge outlet, and a steam outlet.

[0063] The tower-type esterification reactor for the preparation of pentaerythritol oleate provided in this application adopts a multi-layered, stepped composite plate tower structure, which can achieve coupling of material reaction and separation phases. When only a high-temperature transesterification reaction distillation section is available, vacuum operation is preferred. The trays of the high-temperature transesterification reaction distillation section are columnar structures or shallow pan structures with overflow ports, which can effectively control the hydraulic residence time of the material by adjusting the liquid holdup and operating conditions, thereby achieving continuous production of pentaerythritol oleate. The reactor provided in this application has a semi-series-semi-parallel structure (liquid phase flows through the trays in series, and vapor phase leaves the trays in parallel) high-temperature transesterification reaction distillation section, which can form a large surface area shallow / thin liquid layer. While the stepped reaction occurs in each composite plate, it ensures the timely and effective removal of small molecule volatile components at the end of the esterification reaction.

[0064] Those skilled in the art will understand that the above-described embodiments are specific examples of implementing this application, and in practical applications, various changes in form and detail may be made without departing from the spirit and scope of this application. Any person skilled in the art can make their own modifications and alterations without departing from the spirit and scope of this application; therefore, the scope of protection of this application should be determined by the scope defined in the claims.

Claims

1. A tower-type esterification reactor for the preparation of pentaerythritol oleate, characterized in that, include: The tower body and the multiple layers of trays distributed within the tower body; The tower body includes a high-temperature transesterification reaction distillation section with parallel gas flow and series liquid flow between each tray. In the high-temperature transesterification reaction distillation section, the liquid fluid flows sequentially from top to bottom through each tray and finally falls to the bottom of the reactor. After the gaseous fluid evaporates from each tray, it flows through the gas flow channel to the condenser for condensation. After the condensate is dehydrated or separated, the organic matter is returned to the tower reactor and the water is discharged. The tower body is also equipped with a feed inlet, a discharge outlet, and a steam exhaust outlet; The tower body also includes a medium-temperature esterification reaction distillation section with countercurrent series flow of gas and liquid phases between each layer of tower plates, and the medium-temperature esterification reaction distillation section is located above the high-temperature transesterification reaction distillation section. In the intermediate-temperature esterification reaction distillation section, the liquid phase passes through the trays in series from top to bottom, and finally falls into the top tray of the high-temperature ester exchange reaction distillation section; the gas phase passes through each tray in series from bottom to top, and then gathers at the top of the reactor column. It then flows through the gas phase flow channel to the condenser for condensation. After the condensate is dehydrated or separated, the organic matter is returned to the reactor and the water is discharged. In the high-temperature transesterification reaction distillation section, the gaseous fluid leaves each tray and directly enters the medium-temperature esterification reaction rectification section; The trays of the medium-temperature esterification reaction distillation section are equipped with multiple sieve holes and bubble caps; The bubble cap is equipped with a riser pipe, and the lower part of the bubble cap has a toothed slit. The gas phase rises from the riser pipe, passes through the cyclic passage between the bubble cap and the riser pipe, and escapes from the liquid layer through the toothed slit at the lower part of the bubble cap. The liquid phase passes through the sieve holes, so that the liquid falls to the next layer. The feed rate is greater than the liquid falling rate, which generates countercurrent and makes the reaction more complete.

2. The tower-type esterification reactor for the preparation of pentaerythritol oleate according to claim 1, characterized in that, The trays of the high-temperature transesterification distillation section are columnar structures or shallow dish structures with overflow outlets.

3. The tower-type esterification reactor for the preparation of pentaerythritol oleate according to claim 2, characterized in that, The gas phase channels and liquid phase channels of the trays in the high-temperature transesterification distillation section are staggered.

4. The tower-type esterification reactor for the preparation of pentaerythritol oleate according to claim 1, characterized in that, The liquid phase fluid is a mixture of pentaerythritol, small molecule alcohol and oleic acid, wherein the ratio of pentaerythritol to oleic acid is 4~4.2:1; The small molecule alcohols include one or more of methanol, ethanol, butanol, isoamyl alcohol, and diisoamyl alcohol.

5. The tower-type esterification reactor for the preparation of pentaerythritol oleate according to claim 1, characterized in that, The tray is a composite tray composed of packing and a plate; The packing material is either a random packing or a structured packing material loaded with a catalyst.

6. The tower-type esterification reactor for the preparation of pentaerythritol oleate according to claim 5, characterized in that, A random packing material supported on a catalyst, wherein the catalyst active component includes one or more of the following: solid acid supported on a particulate support, stannous oxalate crystals, and cation exchange resin.

7. The tower-type esterification reactor for the preparation of pentaerythritol oleate according to claim 1, characterized in that, The feed inlet and the exhaust outlet are located at the top of the tower body. The oleic acid and pentaerythritol reactants, which are mixed in proportion, enter the top of the tower body through the feed inlet and then disperse onto the trays inside the tower body. The exhaust outlet is connected to the condenser. The discharge port is located at the bottom of the tower body and is used to discharge pentaerythritol oleate. A filtration mechanism is installed in the pipeline of the discharge port to remove solid particulate impurities.

8. The tower-type esterification reactor for the preparation of pentaerythritol oleate according to claim 1, characterized in that, At least one tray is equipped with a heater, which controls the internal temperature of the esterification reactor by heating the tray and evaporating the material.

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