Tower type esterification reactor for preparing pentaerythritol oleate

Abstract

The invention relates to the technical field of esterification production process equipment, in particular to a tower type esterification reactor for preparing pentaerythritol oleate, which comprises a tower body and a plurality of layers of tower plates distributed in the tower body, the tower body comprises a high-temperature ester exchange reaction distillation section with the characteristics of gas-phase parallel flow and liquid-phase series flow between tower plates; in the high-temperature ester exchange reaction distillation section, liquid-phase fluid is connected in series step by step from top to bottom, sequentially flows through each layer of tower plate and finally falls into a reactor tower kettle; the gas-phase fluid is volatilized from each layer of tower plate and then enters a condenser for condensation through a gas-phase circulation channel, after the condensate is dehydrated or subjected to water separation, organic matters return to the tower reactor, and water is discharged; and the tower body is also provided with a feed port, a discharge port and a steam exhaust port. The tower type esterification reactor for preparing pentaerythritol oleate provided by the invention solves the problems of poor esterification reaction continuity, low reaction efficiency, poor esterification rate, poor material adaptability and the like in the prior art.

Description

Technical Field

[0001] The present application relates to the technical field of esterification production process equipment, and in particular to a tower esterification reactor for preparing pentaerythritol oleate. Background Art

[0002] Pentaerythritol oleate is widely used in many fields, including as an anti-wear and water resistance improver in lubricating oil, a lubricant and release agent in plastic processing, and an additive in textiles and coatings. China is one of the main producers of pentaerythritol oleate in the world, and is also one of the major exporters of pentaerythritol oleate. With the growth of market demand and the increase of production capacity in the future, it is expected that the export volume will continue to grow. With the global emphasis on environmental protection and sustainable development, the market demand for pentaerythritol oleate shows a trend of continuous growth due to its excellent performance and environmental protection characteristics.

[0003] The synthesis reaction of pentaerythritol oleate is the esterification reaction of pentaerythritol and oleic acid. The generated water needs to be continuously evaporated to ensure that the esterification reaction is complete. In the production process, the mass transfer interface area, reaction pressure, residence time and temperature need to be strictly controlled to ensure that the generated water is removed in time, so that the reaction proceeds in a positive direction and a higher esterification rate is obtained. In addition, the material temperature must be regulated during the treatment process to avoid excessively high temperatures leading to a large number of side reactions and a darkening of the product color. The optimization of the process and the realization of technical conditions directly affect the corresponding production cost and production efficiency, which puts high demands on the process and internal structure of the preparation device.

[0004] The production of pentaerythritol oleate by the transesterification method has the characteristics of easy control of the reaction process and product quality indicators, but it is necessary to first prepare low-boiling alcohol oleate, and then carry out transesterification reaction with pentaerythritol, and the low-boiling alcohol produced by the transesterification is condensed and recovered. The two-step esterification transesterification method requires a lot of time and energy consumption, has many esterification reaction steps, poor continuity, low production efficiency and high preparation energy consumption, and the color of the final product will also be affected.

[0005] Esterification reactions are generally carried out using traditional tank reactors. However, since the materials are in a fully mixed state, it takes a long time to reach reaction equilibrium, and the purity of the product at the end of the reaction is not high due to the limitations of the initial material composition (for example, an excess of a reactant). In addition, the mass transfer interface of the tank reactor is limited by the diameter of the tank. Even if it is fully stirred, it is difficult to remove the esterification product water in a timely and sufficient manner, which further delays the generation efficiency of the target esterification product.

[0006] In order to improve the efficiency of the esterification reaction, some researchers have developed a reactive distillation process based on traditional distillation tower equipment. Through the difference in liquid material components generated by the gas-liquid phase equilibrium on different tower plates, the coupling of reaction and separation can be achieved, and the catalyst can be combined with the filler to improve the efficiency of the reaction. However, the traditional tower reactor is limited by the volatility of the material and is only suitable for the esterification reaction of low-boiling point materials. Otherwise, too high a kettle temperature will lead to deterioration of product quality, and too high a vacuum will lead to limited tower pressure drop (further limiting the number of tower plates or packing height), and process control is difficult to carry out stably. In addition, in the traditional tower reactor, the product water generated during the esterification reaction will pass through each layer of the tower plate step by step, which will inhibit the esterification reaction in the corresponding area and reduce the efficiency of product generation. Summary of the invention

[0007] The embodiment of the present application provides a tower esterification reactor for preparing pentaerythritol oleate, so as to solve the problems existing in the prior art such as poor continuity of the esterification reaction, low reaction efficiency, poor esterification rate and material adaptability.

[0008] In order to solve the above technical problems, the embodiment of the present application provides a tower esterification reactor for the preparation of pentaerythritol oleate, comprising: a tower body and a plurality of tower plates distributed in the tower body; the tower body comprises a high-temperature ester exchange reaction distillation section having the characteristics of gas phase parallel flow and liquid phase series flow between each layer of tower plates; in the high-temperature ester exchange reaction distillation section, the liquid phase fluid flows through each layer of tower plates in series from top to bottom, and finally falls into the reactor kettle; after the gas phase fluid evaporates from each layer of tower plates, it is condensed in a condenser through a gas phase flow channel, and after the condensate is dehydrated or separated, the organic matter returns to the tower reactor and the water is discharged; the tower body is also provided with a feed port, a discharge port and a steam exhaust port.

[0009] In some exemplary embodiments, the tower body also includes a medium-temperature esterification reaction distillation section with the characteristics of gas and liquid countercurrent series connection between each layer of tower plates, and the medium-temperature esterification reaction distillation section is located above the high-temperature ester exchange reaction distillation section; in the medium-temperature esterification reaction distillation section, the liquid phase passes through the tower plates in series from top to bottom, and finally falls into the topmost tower plate of the high-temperature ester exchange reaction distillation section; the gas phase passes through each level of tower plates in series from bottom to top, and then converges at the top of the reactor tower, and is condensed in the condenser through the gas phase flow channel. After the condensate is dehydrated or water-separated, the organic matter returns to the reactor and the water is discharged; in the high-temperature ester exchange reaction distillation section, the gas phase fluid directly enters the medium-temperature esterification reaction distillation section after leaving each level of tower plates.

[0010] In some exemplary embodiments, a plurality of sieve holes and bubbles are provided on the tower plate of the medium-temperature esterification reaction distillation section; a riser is provided in the bubble, and teeth are provided at the lower part of the bubble; the gas phase rises from the riser, escapes from the liquid layer through the teeth at the lower part of the bubble through a revolving passage between the bubble and the riser, and passes through the sieve holes, so that the liquid falls to the next layer, and the feed rate is greater than the liquid descending rate, resulting in a countercurrent, which makes the reaction more complete.

[0011] In some exemplary embodiments, the tray of the high-temperature transesterification reaction distillation section is a columnar structure or a shallow tray structure with an overflow port.

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

[0013] In some exemplary embodiments, 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 to 4.2:1; the small molecule alcohol includes one or more of methanol, ethanol, butanol, isopentanol and diisopentanol.

[0014] In some exemplary embodiments, the tower plate is a composite tower plate composed of a filler and a plate; the filler is a random filler or a structured filler loaded with a catalyst.

[0015] In some exemplary embodiments, the random packing is loaded with a catalyst, wherein the catalyst active component comprises one or more of a solid acid loaded on a granular carrier, stannous oxalate crystals, and a cation exchange resin.

[0016] In some exemplary embodiments, the feed port and the exhaust port are located at the top of the tower body, and the oleic acid and pentaerythritol reactants mixed in proportion enter the top of the tower body through the feed port, and then disperse and fall onto the tower plates in the inner cavity of the tower body; the exhaust port is connected to the condenser; the discharge port is located at the bottom of the tower body, and is used to discharge pentaerythritol oleate to the outside; a filtering mechanism is provided in the pipeline of the discharge port, which is used to remove solid particulate impurities.

[0017] In some exemplary embodiments, at least one layer of the tower plate is provided with a heater, and the internal temperature of the esterification reactor is controlled by heating the tower plate and evaporating the material.

[0018] The technical solution provided by the embodiments of the present application has at least the following advantages:

[0019] The embodiment of the present application provides a tower esterification reactor for preparing pentaerythritol oleate, comprising: a tower body and a plurality of tower plates distributed in the tower body; the tower body comprises a high-temperature transesterification reaction distillation section having the characteristics of gas phase parallel flow and liquid phase series flow between each layer of the tower plates; in the high-temperature transesterification reaction distillation section, the liquid phase fluid flows through each layer of the tower plates in series from top to bottom, and finally falls into the reactor kettle; after the gas phase fluid evaporates from each layer of the tower plates, it is condensed in a condenser through a gas phase flow channel, and after the condensate is dehydrated or separated, the organic matter returns to the tower reactor and the water is discharged; the tower body is also provided with a feed port, a discharge port and a steam exhaust port.

[0020] The tower esterification reactor for the preparation of pentaerythritol oleate provided by the present application adopts a multi-layer stepped composite plate tower structure, which can realize the reaction and separation of materials. When there is only a high-temperature transesterification reaction distillation section, it is preferably operated by vacuum, and the tower plate of the high-temperature transesterification reaction distillation section is a columnar structure or a shallow plate structure with an overflow port, which can effectively realize the regulation of the hydraulic residence time of the material by adjusting the liquid holding capacity and operating conditions, so as to realize the continuous production of pentaerythritol oleate. The reactor provided by the present application has a high-temperature transesterification reaction distillation section with a semi-series and semi-parallel structure (liquid phase flows through the tower plate in series, and the vapor phase leaves the tower plate in parallel), which can form a large surface area shallow layer / thin layer of liquid layer, and while the step reaction occurs in each composite plate, it provides a guarantee for the timely and effective removal of small molecule volatile components in the late stage of the esterification reaction. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] One or more embodiments are exemplarily described by pictures in the corresponding drawings, and these exemplifications do not constitute limitations on the embodiments. Unless otherwise stated, the pictures in the drawings do not constitute proportional limitations.

[0022] Figure 1 A schematic structural diagram of a tower esterification reactor for preparing pentaerythritol oleate provided in one embodiment of the present application.

[0023] Figure 2 A schematic diagram of the structure of a tower plate of a medium-temperature esterification reaction distillation section provided in one embodiment of the present application.

[0024] Figure 3 A schematic diagram of the structure of a tower plate of a high-temperature transesterification reaction distillation section provided in one embodiment of the present application.

[0025] Figure 4 A schematic structural diagram of a composite tower plate with a columnar structure and an overflow port provided in one embodiment of the present application.

[0026] Figure 5 A schematic structural diagram of a composite tower plate with a disc-shaped structure and an overflow port provided in one embodiment of the present application.

[0027] Figure 6 A top view of a composite tower plate with a columnar structure and an overflow port provided in one embodiment of the present application.

[0028] Figure 7 A top view of a composite tower plate with a shallow tray structure and an overflow port provided in one embodiment of the present application.

[0029] Among them, the reference numerals in the figure are: 1. feed inlet; 2. medium-temperature esterification reaction distillation section; 21. bubble plate; 211. bubble; 212. sieve hole; 22. filler; 3. high-temperature transesterification reaction distillation section; 31. composite tower plate with a columnar structure with an overflow port; 32. composite tower plate with a shallow tray structure with an overflow port; 4. exhaust port; 5. discharge port. DETAILED DESCRIPTION

[0030] From the background technology, it can be seen that the existing kettle reactor has problems such as low mass transfer efficiency, limited reaction efficiency, and inability to produce continuously; the existing tower reactor has problems such as being difficult to apply to high-temperature materials, and the product water passing through the reaction and separation zone layer by layer affecting the reaction efficiency.

[0031] In order to solve the above technical problems, the embodiment of the present application provides a tower esterification reactor for the preparation of pentaerythritol oleate, comprising: a tower body and multiple layers of tower plates distributed in the tower body; the tower body includes a high-temperature transesterification reaction distillation section with the characteristics of gas phase parallel flow and liquid phase series flow between each layer of tower plates; in the high-temperature transesterification reaction distillation section, the liquid phase fluid flows through each layer of tower plates in series from top to bottom, and finally falls to the reactor tower kettle; after the gas phase fluid evaporates from each layer of tower plates, it is condensed in the condenser through the gas phase flow channel, and after the condensate is dehydrated / watered, the organic matter returns to the tower reactor and the water is discharged; the tower body is also provided with a feed port, a discharge port and a steam exhaust port. The present application provides a tower esterification reactor for the preparation of pentaerythritol oleate to solve the problems of poor continuity of esterification reaction, low reaction efficiency, poor esterification rate and material adaptability existing in the prior art.

[0032] The following will describe the various embodiments of the present application in detail with reference to the accompanying drawings. However, it will be appreciated by those skilled in the art that in the various embodiments of the present application, many technical details are provided in order to enable the reader to better understand the present application. However, even without these technical details and various changes and modifications based on the following embodiments, the technical solution claimed in the present application can be implemented.

[0033] See also Figure 1The embodiment of the present application provides a tower esterification reactor for preparing pentaerythritol oleate, comprising: a tower body and a plurality of tower plates distributed in the tower body; the tower body comprises a high-temperature transesterification reaction distillation section 3 having the characteristics of gas phase parallel flow and liquid phase series flow between each layer of tower plates; in the high-temperature transesterification reaction distillation section 3, the liquid phase fluid flows through each layer of tower plates in series from top to bottom, and finally falls into the reactor kettle; after the gas phase fluid evaporates from each layer of tower plates, it is condensed in a condenser through a gas phase flow channel, and after the condensate is dehydrated / watered, the organic matter returns to the tower reactor and the water is discharged; the tower body is also provided with a feed port 1, a steam exhaust port 4 and a discharge port 5.

[0034] In some embodiments, the tower body also includes a medium-temperature esterification reaction distillation section 2 with the characteristics of gas and liquid countercurrent series connection between each layer of tower plates, and the medium-temperature esterification reaction distillation section 2 is located above the high-temperature ester exchange reaction distillation section 3; in the medium-temperature esterification reaction distillation section 2, the liquid phase passes through the tower plates in series from top to bottom, and finally falls into the topmost tower plate of the high-temperature ester exchange reaction distillation section 3; the gas phase passes through the tower plates of each level in series from bottom to top, and then converges at the top of the reactor tower, and is condensed in the condenser through the gas phase flow channel. After the condensate is dehydrated or water-separated, the organic matter returns to the reactor and the water is discharged.

[0035] It should be noted that the tower body of the esterification reactor of the present application may not be provided with the medium-temperature esterification reaction distillation section 2, but only with the high-temperature transesterification reaction distillation section 3. When the medium-temperature esterification reaction distillation section 2 is not provided, the gas phase fluid of the high-temperature transesterification reaction distillation section 3 evaporates from each layer of the tower plate, and then condenses in the condenser through the gas phase flow channel. After the condensate is dehydrated / watered, the organic matter returns to the tower reactor, and the water is discharged.

[0036] When a medium-temperature esterification reaction distillation section 2 is provided in the tower body of the esterification reactor, in the high-temperature transesterification reaction distillation section 3, the gas phase fluid directly enters the medium-temperature esterification reaction distillation section 2 after leaving each stage of the tower plate. The tower esterification reactor of the present application can be operated under pressurized, normal pressure or vacuum conditions. When there is only a high-temperature transesterification reaction distillation section, vacuum operation is preferably adopted.

[0037] like Figure 2 As shown, in some embodiments, a plurality of sieve holes 212 and bubbles 211 are provided on the tower plate (which may be referred to as the bubble plate 21) of the medium-temperature esterification reaction distillation section 2; a riser is provided in the bubble 211, and a tooth gap is opened at the lower part of the bubble 211; the gas phase rises from the riser, escapes from the liquid layer through the tooth gap at the lower part of the bubble 211 through the revolving passage between the bubble 211 and the riser; the liquid phase passes through the sieve hole 212, so that the liquid falls to the next layer, and the feed speed is greater than the liquid descending speed, resulting in a countercurrent, so that the reaction is more complete.

[0038] In some embodiments, the tower plate of the high-temperature transesterification reaction distillation section 3 is a columnar structure or a shallow tray structure with an overflow port.

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

[0040] In some embodiments, 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 to 4.2:1; the small molecule alcohol includes one or more of methanol, ethanol, butanol, isopentanol and diisopentanol.

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

[0042] In some embodiments, the tower plate is a composite tower plate composed of a filler and a plate; the filler is a random packing or a structured packing loaded with a catalyst, preferably a random packing. The tower internals structure of the medium-temperature esterification reaction distillation section adopts the form of traditional tower equipment, and a liquid distribution component is arranged between the tower plates of the high-temperature transesterification reaction distillation section.

[0043] Aiming at specific production conditions and process requirements, during the equipment design stage, the liquid holding capacity of the composite tower plate of filler + plate can be regulated by adjusting the equipment structure and size; during the operation stage, the hydraulic residence time of the fluid flowing through the composite tower plate can be regulated by controlling the operating conditions.

[0044] In some embodiments, the random packing loaded with a catalyst, wherein the catalyst active component comprises one or more of a solid acid, stannous oxalate crystals, and a cation exchange resin loaded on a granular carrier. The particulate matter loaded with the catalytic active component or the catalytic active component crystal particles can be formed into a random packing or a structured packing in the form of coating or bonding.

[0045] In some embodiments, the feed port and the exhaust port are located at the top of the tower body, and the oleic acid and pentaerythritol reactants mixed in proportion enter the top of the tower body through the feed port, and then disperse and fall onto the tower plates in the inner cavity of the tower body; the exhaust port is connected to the condenser; the discharge port is located at the bottom of the tower body, and is used to discharge pentaerythritol oleate to the outside; a filtering mechanism is provided in the pipeline of the discharge port, which is used to remove solid particulate impurities.

[0046] It should be noted that the tower esterification reactor is also provided with interfaces such as instrument ports, which are arranged at the tower plate. Oleic acid and pentaerythritol reactants mixed in proportion enter the tower top through the feed pipeline, and then disperse and fall onto the composite plate in the tower cavity; small molecule alcohol can enter the tower from the top of the tower together with the mixture of oleic acid and pentaerythritol in the form of liquid phase, or can enter the tower from the bottom or middle of the medium-temperature esterification reaction distillation section in the form of vapor phase.

[0047] In the medium-temperature esterification reaction distillation section, the rising vapor phase is condensed by the condenser, and the organic matter returns to the tower reactor after the condensate is dehydrated / watered, and the water is discharged from the system. In the high-temperature transesterification reaction distillation section, the gas phase fluid evaporates from each layer of the tower plate in parallel. The large surface area shallow / thin liquid layer brought by the multi-layer composite tower plate increases the removal rate of by-product water and small molecular volatile components.

[0048] The condensate obtained by the condenser is dehydrated, and the separated organic components such as low-boiling point alcohol can be recycled as small molecular alcohol materials, thereby reducing material consumption and the generation of three wastes.

[0049] In some embodiments, at least one tray is provided with a heater, and the temperature inside the esterification reactor is controlled by heating the tray and evaporating the material. When the material is in a non-boiling state, the evaporation of the material will become slow, and the process is mainly in a temperature-insulating state with fine-tuning of the temperature.

[0050] The tower esterification reactor for preparing pentaerythritol oleate provided in the present application is described in detail below through specific examples.

[0051] Example 1

[0052] Reference Figure 1The present application provides a tower esterification reactor for preparing pentaerythritol oleate to improve the degree of reaction. The esterification reaction device includes a feed port 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 exhaust port 4; a discharge port 5. The feed port 1 includes an oleic acid feed port, a low-boiling alcohol reactant feed port, and a pentaerythritol feed port; the reaction material passes through the esterification reaction feed pipe, and a certain proportion of oleic acid and low-boiling alcohol reactants are transported, and the raw materials are pre-mixed by pretreatment, and are dispersed from the top of the tower through the coil and fall into the composite tower plate of the tower cavity; the filler loaded with the catalyst forms a fixed filler and is placed on the reactor tower plate to cause esterification reaction. A heater is provided on one or several tower plates inside the tower esterification reactor, and the internal temperature of the esterification reactor can be controlled through the instrument port structure at the tower plate. The medium-temperature esterification reaction distillation section 2 in the catalytic reaction tower is provided with one or more layers of composite tower plates (reaction layers) and fillers 22, and the composite tower plates are preferably bubble cap plates 21; the high-temperature transesterification reaction distillation section 3 in the catalytic reaction tower is provided with one or more layers of composite tower plates (reaction layers) and fillers 22, and the composite tower plates can be composite tower plates with a columnar structure or a shallow tray structure with an overflow port, such as Figure 4 and Figure 5 As shown, the composite plate is a composite tower plate 31 of a columnar structure with an overflow port or a composite tower plate 32 of a shallow plate structure with an overflow port; the exhaust port 4 of the esterification reaction tower is connected to the condenser, and a discharge port 5 is provided at the bottom of the tower esterification reactor for discharging pentaerythritol oleate to the outside, and a filtering mechanism is provided in the discharge port pipeline for removing solid particulate impurities.

[0053] Example 2

[0054] The present application provides a tower esterification reactor for preparing pentaerythritol oleate. Compared with the prior art, the tower plates in the reactor are composite tower plates of fillers + plates. Figure 2, wherein the tower plate of the medium-temperature esterification reaction distillation section 2 can be a sieve hole 212 and a bubble cap 211 structure, preferably a bubble cap plate 21. There is a riser inside the bubble cap, and the gas phase rises from the riser, and escapes from the liquid layer through the tooth gap opened at the bottom of the bubble cap 211 through the rotating passage between the bubble cap 211 and the riser. The liquid phase passes through the sieve hole 212, so that the liquid falls to the next layer, and the feed rate is greater than the liquid descending rate, resulting in a countercurrent, so that the reaction is more sufficient. This product can be purchased from the market, and the specific surface area of ​​the bubble cap 211 tower plate is large, which can provide sufficient gas-liquid contact surface, which is a key factor in the mass transfer process and can effectively improve mass transfer and heat transfer. According to the type of filler in the tower and the requirements of the separated system, the size and number of the bubble caps are designed to make the gas and liquid evenly distributed, avoid liquid blockage caused by excessive concentration or dead corners, and also reduce direct collisions between gas and liquid, and avoid the occurrence of surface wall attachment. The presence of the bubble cap 211 reduces the resistance of gas and liquid passing through the packing, which can save power consumption and reduce energy consumption, thereby improving mass transfer efficiency and making the tray efficiency higher. The bubble cap tray has good production capacity and can meet large-scale production needs.

[0055] Example 3

[0056] The tower plate of the high temperature transesterification reaction distillation section 3 can be a columnar structure or a shallow tray structure with an overflow port. Figure 4 and Figure 5 The baffle of the composite tower plate 31 with a columnar structure and an overflow port or the composite tower plate 32 with a shallow dish structure and an overflow port acts as a gas-liquid phase channel. The rising gas phase in the tower passes through the tower plate into the packing layer above and into the upper layer. It evenly distributes the gas phase and has low resistance. It is convenient to arrange the small holes for liquid distribution. The total area accounts for 15% of the tower cross section. The cross section of the columnar gas phase channel can be circular or rectangular. The diameter of the circular gas phase channel is generally 200mm to 300mm. Usually, the cross section of the rectangular gas phase channel is larger than that of the circular gas phase channel. The height of the baffle of the columnar structure or the shallow dish structure can be determined according to needs, but the standard height is 250mm. The high liquid level should be 25mm to 50mm lower than the upper edge of the baffle. The operational flexibility is determined by the high liquid level and the low liquid level. Reference Figure 6 and Figure 7 The columnar structure or shallow tray structure is installed at a position where, in the top view, it can be seen that the gas-liquid phase channels of the upper and lower trays are staggered and distributed, and are symmetrical along the axis on the plane.

[0057] Example 4

[0058] The equipment system can be operated under pressurized, normal pressure or vacuum conditions. When there is only the high-temperature ester exchange reaction distillation section 3, vacuum operation is preferably used. There are two situations. One composite plate can be a columnar structure with an overflow port. When vacuuming, in the high-temperature ester exchange reaction distillation section 3, the rising gas phase passes through the pores left in the middle and passes through each level of tower plates from bottom to top. The gas phase fluid evaporates from each layer of tower plates in parallel, and the liquid phase passes through the tower plates in series from top to bottom. By setting a columnar structure tower plate with an overflow port, the liquid phase flows from the pore edge baffle to the next layer. Through the pores, the gas phase flows through the channel to the condenser for condensation. After the condensate is dehydrated / watered, the organic matter returns to the tower reactor and the water is discharged. One composite plate can be a disc-shaped structure with an overflow port. Please refer to Figure 3 When vacuuming, in the high-temperature transesterification reaction distillation section, the rising gas phase passes through the gaps left on the side and passes through the tower plates from bottom to top. The gas phase fluid evaporates from the tower plates in parallel, and the liquid phase passes through the tower plates in series from top to bottom. By setting a shallow tray structure tower plate with an overflow port, the liquid phase flows from the baffle to the next layer. The shallow tray or columnar structure of the composite plate can effectively control the hydraulic residence time of the material by adjusting the liquid holding capacity and operating conditions, adapting to different production needs, thereby realizing the continuous production of pentaerythritol oleate.

[0059] Example 5

[0060] Reference Figure 1 In the medium-temperature esterification reaction distillation section 2, the gas phase and liquid phase are countercurrently connected in series between each layer of the tower plate. The liquid phase passes through the tower plates in series from top to bottom, and finally falls into the topmost tower plate of the high-temperature transesterification reaction distillation section 3; the gas phase passes through the tower plates in series from bottom to top, and then gathers at the top of the reactor tower. The gas phase flows through the exhaust port 4 to the condenser for condensation. After the condensate is dehydrated / water separated, the organic matter returns to the tower reactor and the water is discharged. Figure 4 and Figure 5 In the high-temperature transesterification reaction distillation section, the layers of tower plates have the characteristics of gas phase parallel flow and liquid phase series flow. The liquid phase fluid flows through each layer of tower plates in series from top to bottom, and finally falls to the tower kettle; the gas phase fluid flows in parallel, and after leaving each level of tower plates, it directly enters the medium-temperature esterification reaction distillation section. The large surface area shallow / thin liquid layer brought by the multi-layer composite tower plates increases the removal rate of by-product water and small molecular volatile components.

[0061] The condensate obtained by the condenser is dehydrated, and the separated organic components such as low-boiling point alcohol can be recycled as small molecular alcohol materials, thereby reducing material consumption and the generation of three wastes.

[0062] According to the above technical scheme, the embodiment of the present application provides a tower esterification reactor for preparing pentaerythritol oleate, comprising: a tower body and a plurality of tower plates distributed in the tower body; the tower body comprises a high-temperature transesterification reaction distillation section having the characteristics of gas phase parallel flow and liquid phase series flow between each layer of tower plates; in the high-temperature transesterification reaction distillation section, the liquid phase fluid flows through each layer of tower plates in series from top to bottom, and finally falls into the reactor kettle; the gas phase fluid directly enters the medium-temperature esterification reaction distillation section after leaving each layer of tower plates; the tower body is also provided with a feed port, a discharge port and a steam exhaust port.

[0063] The tower esterification reactor for the preparation of pentaerythritol oleate provided by the present application adopts a multi-layer stepped composite plate tower structure, which can realize the reaction and separation of materials. When there is only a high-temperature transesterification reaction distillation section, it is preferably operated by vacuum, and the tower plate of the high-temperature transesterification reaction distillation section is a columnar structure or a shallow plate structure with an overflow port, which can effectively realize the regulation of the hydraulic residence time of the material by adjusting the liquid holding capacity and operating conditions, so as to realize the continuous production of pentaerythritol oleate. The reactor provided by the present application has a high-temperature transesterification reaction distillation section with a semi-series and semi-parallel structure (liquid phase flows through the tower plate in series, and the vapor phase leaves the tower plate in parallel), which can form a large surface area shallow layer / thin layer of liquid layer, and while the step reaction occurs in each composite plate, it provides a guarantee for the timely and effective removal of small molecule volatile components in the late stage of the esterification reaction.

[0064] Those skilled in the art can understand that the above-mentioned embodiments are specific examples for implementing the present application, and in practical applications, various changes can be made to them in form and detail without departing from the spirit and scope of the present application. Any person skilled in the art can make their own changes and modifications without departing from the spirit and scope of the present application, so the scope of protection of the present application shall be based on the scope defined in the claims.

Claims

1. A tower esterification reactor for preparing pentaerythritol oleate, characterized in that: include: A tower body and multiple layers of tower plates distributed in the tower body; The tower body comprises a high-temperature transesterification reaction distillation section with the characteristics of gas phase parallel flow and liquid phase series flow between each layer of tower plates; in the high-temperature transesterification reaction distillation section, the liquid phase fluid flows through each layer of tower plates in series from top to bottom, and finally falls into the reactor tower kettle; after the gas phase fluid evaporates from each layer of tower plates, it is condensed in the condenser through the gas phase flow channel, and after the condensate is dehydrated or separated, 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 inlet and a steam exhaust inlet.

2. The tower esterification reactor for preparing pentaerythritol oleate according to claim 1, characterized in that: The tower body also includes a medium-temperature esterification reaction distillation section with gas phase and liquid phase countercurrent series connection between each layer of the tower plates, and the medium-temperature esterification reaction distillation section is located above the high-temperature transesterification reaction distillation section; In the medium-temperature esterification reaction distillation section, the liquid phase passes through the tower plates in series from top to bottom, and finally falls into the topmost tower plate of the high-temperature transesterification reaction distillation section; the gas phase passes through the tower plates in series from bottom to top, and then gathers at the top of the reactor tower, and is condensed in the condenser through the gas phase flow channel. After the condensate is dehydrated or water-separated, the organic matter returns to the reactor and the water is discharged; In the high-temperature transesterification reaction distillation section, the gas phase fluid directly enters the medium-temperature esterification reaction distillation section after leaving each stage of the tower plates.

3. The tower esterification reactor for preparing pentaerythritol oleate according to claim 2, characterized in that: The tower plate of the medium-temperature esterification reaction distillation section is provided with a plurality of sieve holes and bubble caps; The bubble is provided with a riser pipe, and the lower part of the bubble is provided with slits; the gas phase rises from the riser pipe, escapes from the liquid layer through the slits at the lower part of the bubble through the revolving passage between the bubble and the riser pipe; the liquid phase passes through the sieve holes, so that the liquid falls to the next layer, the feed speed is greater than the liquid descending speed, and a countercurrent is generated, so that the reaction is more complete.

4. The tower esterification reactor for preparing pentaerythritol oleate according to claim 1, characterized in that: The tower plate of the high-temperature transesterification reaction distillation section is a columnar structure or a shallow plate structure with an overflow port.

5. The tower esterification reactor for preparing pentaerythritol oleate according to claim 4, characterized in that: The gas phase channels and liquid phase channels of the tower plates of the high-temperature transesterification reaction distillation section are distributed in a staggered manner.

6. The tower esterification reactor for preparing 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 to 4.2:1; The small molecule alcohol includes one or more of methanol, ethanol, butanol, isopentanol, and diisopentanol.

7. The tower esterification reactor for preparing pentaerythritol oleate according to claim 1, characterized in that: The tower plate is a composite tower plate composed of fillers and plates; The filler is a random filler or a structured filler loaded with a catalyst.

8. The tower esterification reactor for preparing pentaerythritol oleate according to claim 6, characterized in that: The random packing is loaded with a catalyst, wherein the active components of the catalyst include one or more of a solid acid loaded on a granular carrier, stannous oxalate crystals, and a cation exchange resin.

9. The tower esterification reactor for preparing pentaerythritol oleate according to claim 1, characterized in that: The feed inlet and the exhaust port are located at the top of the tower body, and the oleic acid and pentaerythritol reactants mixed in proportion enter the top of the tower body through the feed inlet, and then disperse and fall onto the tower plates in the inner cavity of the tower body; the exhaust port is connected to the condenser; The discharge port is located at the bottom end of the tower body and is used to discharge pentaerythritol oleate to the outside; a filtering mechanism is arranged in the pipeline of the discharge port and is used to remove solid particulate impurities.

10. The tower esterification reactor for preparing pentaerythritol oleate according to claim 1, characterized in that: At least one layer of the tower plate is provided with a heater, and the internal temperature of the esterification reactor is controlled by heating the tower plate and evaporating the material.

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