A fatty acid isopropyl ester production apparatus
By setting up a circulating feed system and a gas dehydration device in the esterification reactor, and utilizing the negative pressure reflux of the Venturi tube and the inorganic molecular sieve pervaporation membrane device, the problem of moisture affecting the reaction rate was solved, achieving efficient production of fatty acid isopropyl esters and reducing energy consumption and processing complexity.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- HAIYAN FINE CHEM IND CO LTD
- Filing Date
- 2025-06-27
- Publication Date
- 2026-06-23
AI Technical Summary
In the traditional production process of fatty acid isopropyl esters, it is difficult to remove moisture in time, which leads to a slower reaction rate, complicated subsequent processing, and high energy consumption.
Water and a portion of isopropanol in gaseous state are dehydrated by a gas dehydration device and then refluxed into the esterification reactor under negative pressure in a venturi tube to continue the reaction. Combined with a circulating feed system and an inorganic molecular sieve pervaporation membrane device, the subsequent processing is simplified.
It improved the reaction rate, reduced energy consumption, simplified subsequent processing steps, and further reduced energy consumption.
Smart Images
Figure CN224388801U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the chemical industry, and in particular to a device for producing fatty acid isopropyl esters. Background Technology
[0002] Isopropyl fatty acid esters have a wide range of applications and are indispensable in products such as lubricant additives and metalworking fluid additives. The traditional production process of fatty acid isopropyl esters is as follows: fatty acids with a molar ratio of approximately 1:1.3 and isopropanol, along with an acidic catalyst at a weight ratio of 0.3%-0.5%, are added to an esterification reactor. After all materials are added, the liquid mixture is stirred to allow the fatty acids and isopropanol in the esterification reactor to react fully, producing fatty acid isopropyl esters and water. The reaction ends when the fatty acid content in the liquid mixture in the esterification reactor is less than 1.5%. At this point, the generated fatty acid isopropyl esters can be extracted and subjected to alkali neutralization, water washing, drying, and decolorization to obtain the finished fatty acid isopropyl ester product. Finally, the isopropanol and water in the esterification reactor are evaporated and dehydrated to produce anhydrous isopropanol for reuse. However, this production method has its shortcomings.
[0003] Because water is generated when the fatty end reacts with isopropanol, this water cannot be removed in time and will mix with isopropanol, which slows down the reaction rate.
[0004] After the esterification reaction is stopped and the fatty acid isopropyl ester is extracted, the remaining water and isopropanol in the esterification vessel need to be distilled off and dehydrated. The process is complicated and consumes a lot of energy. Summary of the Invention
[0005] This invention provides a device for producing fatty acid isopropyl esters. By dehydrating the gaseous water and part of the isopropyl alcohol through a gas dehydration device, the dehydrated gaseous isopropyl alcohol is refluxed into the esterification kettle under the negative pressure in the Venturi tube to continue the reaction, thereby increasing the reaction rate. After the esterification reaction is completed, only the excess isopropyl alcohol needs to be distilled off, which simplifies the subsequent processing and greatly reduces energy consumption.
[0006] The technical solution of this utility model is implemented as follows:
[0007] An apparatus for producing fatty acid isopropyl esters, comprising:
[0008] An esterification reactor is used to contain a liquid mixture of fatty acids and isopropanol. When fatty acids and isopropanol react, the temperature of the liquid mixture rises, causing some of the isopropanol and water to be converted from the liquid phase to the gas phase.
[0009] The circulating feed system includes a circulating pump and a venturi tube. The circulating pump is connected to the inside of the esterification reactor, and the venturi tube has a feed end and a discharge end. The feed end is connected to the circulating pump, and the discharge end is connected to the inside of the esterification reactor. The circulating pump can guide part of the liquid phase mixture in the esterification reactor into the venturi tube and form a liquid phase jet that is accelerated and sprayed into the esterification reactor.
[0010] The dehydration and re-reaction system includes a gas dehydration device with a dehydration input end and a dehydration output end. The dehydration input end is connected to the interior of the esterification vessel to introduce gaseous isopropanol and water into the gas dehydration device; the dehydration output end is connected to a venturi tube.
[0011] When the circulation guidance system is working, the liquid jet creates a negative pressure in the venturi tube to attract the dehydrated gaseous isopropanol back to the esterification vessel to react with fatty acids again.
[0012] Preferably, the venturi tube includes a wide-diameter input section and a wide-diameter output section, with a narrow-diameter section integrally formed between the wide-diameter input section and the wide-diameter output section; the end of the wide-diameter input section is the feed end, the end of the wide-diameter output section is the discharge end, and the dehydration output end is connected to the wide-diameter input section; the negative pressure formed by the liquid jet attracts the dehydrated gaseous isopropanol through the narrow-diameter section and then flows back into the esterification reactor.
[0013] Preferably, the circulating pump and the venturi tube are connected by a delivery pipe. The end of the delivery pipe facing the venturi tube passes through the wide-diameter input section and is inserted into the narrow-diameter section. The pressure is the lowest and the flow rate is the highest in the narrow-diameter section, so that the formed liquid jet is injected into the esterification reactor at high speed.
[0014] Preferably, the portion of the delivery pipe inserted into the narrow diameter section is called an insertion section, and the outer diameter of the insertion section is smaller than the inner diameter of the narrow diameter section; so as to form a reflux space between the outer wall of the insertion section and the inner wall of the narrow diameter section, allowing gaseous isopropanol to pass through.
[0015] Preferably, a liquid phase heater is provided between the circulating pump and the venturi tube. The liquid phase heater has a liquid phase heating input end and a liquid phase heating output end. The liquid phase heating input end is connected to the circulating pump, and the liquid phase heating output end is connected to the feed end of the venturi tube, so as to heat part of the liquid phase mixture flowing through the liquid phase heater to a predetermined temperature; so as to maintain the liquid phase mixture in the esterification vessel at the optimal reaction temperature and ensure the reaction rate.
[0016] Preferably, the dehydration output end is connected to the Venturi tube via a gas phase output pipe. The gas phase output pipe is equipped with a self-regulating pressure valve that can open at a predetermined pressure. When the pressure in the gas phase output pipe is less than the predetermined pressure value, the self-regulating pressure valve closes to keep the pressure in the esterification reactor stable. When the pressure in the gas phase output pipe is greater than or equal to the predetermined pressure value, the self-regulating pressure valve opens to allow the dehydrated gas phase isopropanol to pass through.
[0017] Preferably, the Venturi tube is connected to the interior of the esterification vessel along the tangential direction; the resulting liquid jet propels the liquid mixture inside the esterification vessel to rotate along the vertical axis, creating a shaftless stirring effect.
[0018] Preferably, the venturi tube extends obliquely downwards, and the position of the feed end is higher than the position of the discharge end; while the liquid jet pushes the liquid mixture to rotate tangentially, the thrust extends downwards at the same time, causing all the liquid mixture in the esterification vessel to rotate.
[0019] Preferably, a gas phase heater is provided between the dehydration input end and the esterification vessel. The gas phase heater has a gas phase heating input end and a gas phase heating output end. The gas phase heating input end is connected to the esterification vessel, and the gas phase heating output end is connected to the dehydration input end of the gas dehydration device, so as to heat the gas phase isopropanol and water flowing through the gas phase heater to a predetermined temperature; so as to maintain the liquid phase mixture in the esterification vessel at the optimal reaction temperature and ensure the reaction rate.
[0020] Preferably, the gas dehydration device is an inorganic molecular sieve pervaporation membrane device; the inorganic molecular sieve pervaporation membrane device can efficiently remove water through the molecular sieve membrane structure to dehydrate gaseous isopropanol.
[0021] The beneficial effects of this utility model, which adopts the above technical solution, are as follows:
[0022] This invention incorporates a circulating feed system and a dehydration and re-reaction system connected to the esterification reactor. During the esterification reaction, the gaseous water and some isopropanol are dehydrated by a gas dehydration device. The dehydrated gaseous isopropanol is then refluxed back into the esterification reactor under negative pressure in a venturi tube to continue the reaction, thus preventing the generated water from affecting the reaction rate and reducing the reaction time. After the esterification reaction is complete, most of the isopropanol has been reacted, and only a small amount of excess isopropanol needs to be distilled off. Compared with traditional esterification equipment, this simplifies the subsequent processing and greatly reduces energy consumption.
[0023] The Chinese-language tube of the circulating feed system can both attract the dehydrated isopropanol back to the esterification vessel and accelerate the liquid phase mixture discharged by the circulating pump to form a liquid phase jet injected into the esterification vessel. Without the need for a stirring device, the liquid phase jet can tangentially push the liquid phase mixture in the esterification vessel to rotate, thereby playing a stirring role. The design is ingenious and achieves two goals at once. Attached Figure Description
[0024] Figure 1 A schematic diagram of an equipment for producing fatty acid isopropyl esters;
[0025] Figure 2 This is an external view of the esterification reactor;
[0026] Figure 3 This is a schematic diagram of the trajectory of the liquid jet entering the esterification reactor;
[0027] Figure 4 This is a schematic diagram showing the sealed connection between the venturi tube and the delivery pipe.
[0028] Figure 5 This is a cross-sectional view after the venturi tube and the delivery pipe are sealed together.
[0029] Figure 6 A schematic diagram of the stirring mechanism and jacket installed on an existing esterification reactor;
[0030] Figure 7 A simplified structural diagram of an inorganic molecular sieve pervaporation membrane device;
[0031] The attached figures are labeled as follows: 1-Esterification vessel, 1a-Stirring shaft, 1b-Stirring blade, 1c-Jacket, 2-Circulating pump, 3-Venturi tube, 4-Liquid phase heater, 5-Sampling valve, 6-Discharge pump, 7-Gas dehydration device, 8-Automatic pressure valve, 9-Gas phase heater, 10-Automatic safety valve, 11-Connecting pipe, 12-First connection port, 13-Second connection port, 14-Third connection port, 15-... Four connecting ports, 21-feed guide pipe, 31-first wide diameter section, 32-narrow diameter section, 33-second wide diameter section, 34-return port, 35-conveying pipe, 51-sampling pipe, 61-discharge pipe, 71-vacuum pump, 72-wastewater condenser, 73-water outlet pipe, 81-gas phase output pipe, 91-temperature measuring device, 92-gas phase input pipe, 101-condenser, 102-condensate input pipe, 103-feed valve. Detailed Implementation
[0032] To better understand the above-mentioned objectives, features, and advantages of this utility model, the present utility model will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that, unless otherwise specified, the embodiments and features described in these embodiments can be combined with each other.
[0033] Many specific details are set forth in the following description in order to provide a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Therefore, the scope of protection of the present invention is not limited to the specific embodiments disclosed below.
[0034] The specific embodiments of this utility model are as follows:
[0035] like Figure 1-7 As shown, this embodiment provides a fatty acid isopropyl ester production apparatus, including:
[0036] Esterification reactor 1 is used to contain a liquid mixture containing fatty acids and isopropanol. Esterification reactor 1 has a metal body and an enamel layer integrally sintered on the inner wall of the metal body; the enamel layer is more acid-resistant than the metal body. Esterification reactor 1 is equipped with a third connection port 14, on which a feed pipe (not shown) is installed. A feed valve 103 is installed on the feed pipe. During production, the fatty acid and isopropanol materials are preheated to 60°C-80°C. Then, the feed valve 103 is opened, and the fatty acid and isopropanol materials are fed into esterification reactor 1 for the esterification reaction. When fatty acids react with isopropanol, fatty acid isopropyl ester and water are generated. At this time, the temperature of the liquid mixture rises, causing some of the isopropanol and water to convert from the liquid phase to the gas phase.
[0037] The circulating feed system includes a circulating pump 2 and a venturi tube 3. The bottom of the esterification vessel 1 is provided with a fourth connection port 15, which is connected to the circulating pump 2 through a feed pipe 21, so that the circulating pump 2 is connected to the inside of the esterification vessel 1. The venturi tube 3 has a feed end and a discharge end; the feed end is connected to the circulating pump 2, and the discharge end is connected to the inside of the esterification vessel 1. Based on the special structure of the venturi tube 3, the circulating pump 2 can guide part of the liquid phase mixture in the esterification vessel 1 into the venturi tube 3, and form a liquid phase jet that is accelerated and sprayed into the esterification vessel 1.
[0038] The dehydration and re-reaction system includes a gas dehydration device 7, which has a dehydration input end and a dehydration output end. The esterification vessel 1 is provided with a first connection port 12, which is connected to one end of a gas phase input pipe 92. The other end of the gas phase input pipe 92 is connected to the dehydration input end, so that the dehydration input end and the interior of the esterification vessel 1 are connected to introduce gaseous isopropanol and water into the gas dehydration device 7. The dehydration output end is connected to the Venturi tube 3 through a gas phase output pipe 81.
[0039] When the circulation guidance system is working, the liquid jet forms a negative pressure in the venturi tube 3 to attract the dehydrated gaseous isopropanol back to the esterification vessel 1 to react with fatty acids again. Since the water generated in the esterification reaction is removed, the gaseous isopropanol back to the esterification vessel 1 can react fully with the fatty acids. The traditional esterification reaction takes 6-8 hours, and the content of fatty acids is <1.5% when the reaction stops. However, by using the preparation equipment in this embodiment, the esterification reaction time can be reduced to less than 3 hours, thereby improving the reaction rate and production capacity.
[0040] Furthermore, the connection structure between the venturi tube 3 and the circulating pump 2 is as follows: Figure 4-5As shown, the Venturi tube 3 includes a wide-diameter input section 31 and a wide-diameter output section 33, with a narrow-diameter section 32 integrally formed between the wide-diameter input section 31 and the wide-diameter output section 33. The narrow-diameter section 32 is connected to the wide-diameter input section 31 and the wide-diameter output section 33 via a gradually expanding section. The end of the wide-diameter input section 31 is the feed end, and the end of the wide-diameter output section 33 is the discharge end. The dewatering output end is connected to the wide-diameter input section 31. A reflux port 34 is provided on the wide-diameter input end 31, and the end of the gas phase output pipe 81 is sealed to the reflux port 34. To form an optimal... The high-speed jet is connected between the circulating pump 2 and the venturi tube 3 through the delivery pipe 35. The end of the delivery pipe 35 facing the venturi tube 3 passes through the wide-diameter input section 31 and is inserted into the narrow-diameter section 32. When the liquid phase mixture in the delivery pipe 35 flows out to the narrow-diameter section 32, the pressure at the narrow-diameter section 32 is the lowest and the flow rate is the highest, so that the liquid phase jet formed is injected into the esterification vessel 1 at high speed. At the same time, the liquid phase jet forms a negative pressure. At this time, the venturi tube 3 is equivalent to a "suction pump", which will continuously attract the dehydrated gaseous isopropanol through the narrow-diameter section 32 and then flow back to the esterification vessel 1 to carry out the esterification reaction with fatty acids.
[0041] Furthermore, the length of the delivery pipe 35 extending into the narrow diameter section 32 is the insertion section. If the length of the insertion section is too short, a portion of the liquid mixture flowing out of the delivery pipe 35 will easily flow into the wide diameter input section 31, making it difficult for it to flow entirely through the narrow diameter section 32. If the length of the insertion section is too long, the liquid mixture flowing out of the delivery pipe 35 will flow into the wide diameter output section 33 prematurely, resulting in insufficient negative pressure. Therefore, to balance both aspects, the length ratio of the insertion section to the narrow diameter section 32 in this embodiment is in the range of 1:4-4:5.
[0042] Furthermore, the portion of the delivery pipe 35 inserted into the narrow diameter section 32 is called the insertion section. To ensure smooth reflux of the dehydrated gaseous isopropanol, the outer diameter of the insertion section is smaller than the inner diameter of the narrow diameter section 32, so as to form a reflux space between the outer wall of the insertion section and the inner wall of the narrow diameter section 32 that allows the gaseous isopropanol to pass through.
[0043] Furthermore, the optimal reaction temperature for the esterification reaction of fatty acids and isopropanol should be between 85°C and 100°C. Therefore, a liquid phase heater 4 is provided between the circulating pump 2 and the venturi tube 3. The liquid phase heater 4 is typically a tubular type heater, which heats the liquid mixture passing through it by injecting a high-temperature heat exchange liquid. The liquid phase heater 4 also has its own temperature control device to keep the heating temperature within a preset range. In this embodiment, the liquid phase heater temperature is set at 90°C. The liquid phase heater 4 has a liquid phase heating input and a liquid phase heating output. The liquid phase heating input is connected to the circulating pump 2, and the liquid phase heating output is connected to the feed end of the venturi tube 3, so as to heat a portion of the liquid mixture flowing through the liquid phase heater 4 to the predetermined temperature, preventing the temperature inside the esterification reactor 1 from dropping and maintaining the optimal reaction temperature for the liquid mixture inside the esterification reactor 1, thus ensuring the reaction rate.
[0044] Furthermore, the dehydration output end is connected to the Venturi tube 3 via a gas phase output pipe 81. To ensure the stable progress of the esterification reaction, a self-regulating pressure valve 8 that can open at a predetermined pressure is installed on the gas phase output pipe 81. In this embodiment, the pressure set by the self-regulating pressure valve 8 is 0.03±0.01MPa. The self-regulating pressure valve 8 has different effects when it is open and closed. When the pressure in the gas phase output pipe 81 is less than the predetermined pressure value, it indicates that there is less gaseous isopropanol and water entering the gas phase input pipe 91, the reaction rate of the esterification vessel 1 is slow, and its internal pressure is low. At this time, the self-regulating pressure valve 8 is closed to keep the pressure in the esterification vessel 1 stable and prevent the pressure in the esterification vessel 1 from dropping. When the pressure in the gas phase output pipe 81 is greater than or equal to the predetermined pressure value, it indicates that there is more gaseous isopropanol and water produced, and the pressure in the esterification vessel 1 is high enough. At this time, the self-regulating pressure valve 8 is opened to allow the dehydrated gaseous isopropanol to pass through, so that it can be dehydrated and then flow back into the esterification vessel 1 for reaction.
[0045] Furthermore, such as Figure 6 As shown, traditional esterification reactors are equipped with a stirring device to ensure reaction rate and efficiency. This device includes a stirring shaft 1a, with a sealing ring installed at the rotating connection between the stirring shaft 1a and the top of the esterification reactor. The lower end of the stirring shaft 1a is inserted into the esterification reactor, and a stirring blade 1b is connected to the lower end of the stirring shaft 1a. A motor drives the stirring shaft 1a to rotate along a vertical axis, causing the stirring blade 1b to stir the liquid mixture. However, this design has significant drawbacks. Specifically, while the stirring shaft 1a and the top of the esterification reactor form a mechanical seal through the sealing ring, the prolonged rotation of the stirring shaft 1a leads to prolonged contact and friction with the sealing ring, creating gaps. This makes it difficult to achieve a completely sealed environment inside the esterification reactor, resulting in insufficient pressure and inability to reach the required reaction temperature. Because the reaction temperature inside the esterification reactor is not high enough, existing esterification reactors employ... Figure 6The jacket 1c shown is fitted around the lower end of the esterification vessel, and forms a heat exchange space with the outer surface of the esterification vessel. Passing hot water or cool water into the heat exchange space can control the reaction temperature inside the esterification vessel. However, this structure is not simple enough, and repeated heat exchange can easily cause cracking of the acid-resistant enamel layer on the inner wall of the esterification vessel. Therefore, to solve the above problems, such as... Figure 2-3 As shown, this embodiment omits the design of the jacket 1c and the stirring device, allowing a high-speed jet to replace the stirring blade 1b to stir the liquid phase mixture. That is, along the tangential direction of the esterification vessel 1, the Venturi tube 3 is connected to the interior of the esterification vessel 1. The interconnected Venturi tube 3 and the circulating pump 2 constitute a circulating material guiding assembly. When the circulating pump 2 is working, it draws out part of the liquid phase mixture in the esterification vessel 1 and transports it to the Venturi tube 3. The Venturi tube 3 can accelerate the part of the liquid phase mixture and form a liquid phase jet that is accelerated and sprayed into the esterification vessel 1 along the tangential direction of the esterification vessel 1. While attracting the dehydrated isopropanol backflow, the liquid phase jet pushes the liquid phase mixture in the esterification vessel 1 along the vertical axis to rotate along the vertical axis, forming a shaftless stirring effect. This ensures the sealing of the interior of the esterification vessel 1, maintains sufficient reaction temperature and pressure in the esterification vessel 1, and avoids cracking of the enamel layer inside the esterification vessel 1 due to the setting of the jacket 1c. The design is ingenious and achieves multiple benefits.
[0046] Furthermore, to improve the stirring effect, the Venturi tube 3 in this embodiment extends obliquely downward, and the position of the feed end is higher than the position of the discharge end. This design allows the high-speed liquid jet to be sprayed obliquely downward into the esterification vessel 1, forming a spiral spray trajectory. While pushing the liquid mixture to rotate tangentially, the thrust extends downward at the same time, causing all the liquid mixture in the esterification vessel 1 to gradually rotate, ensuring sufficient stirring.
[0047] Furthermore, the connection structure between the esterification vessel 1 and the Venturi tube 3 is as follows: An installation tube 11 extending along the tangential direction of the esterification vessel 1 is integrally connected to the esterification vessel 1. One end of the installation tube 11 integrally connected to the esterification vessel 1 is the first connection end, and the opposite end of the first connection end is the second connection end. The position of the first connection end is lower than the position of the second connection end, so that the installation tube 11 extends downward at an angle. The Venturi tube 3 is sealed to the second connection end, so that the liquid jet is sprayed obliquely downward into the esterification vessel 1 after passing through the Venturi tube 3.
[0048] Furthermore, if the downward angle of the Venturi tube 3 is too large, it will reduce the tangential force of the liquid jet on the liquid mixture. If the downward angle of the Venturi tube 3 is too small, it will be difficult to transmit the circumferential thrust downward, thus affecting the stirring effect. Therefore, in order to ensure that the liquid jet gradually transmits the circumferential thrust downward while pushing the liquid mixture to rotate tangentially, so that the liquid mixture in the entire esterification vessel 1 rotates, in this embodiment, the angle range of the axis of the Venturi tube 3 to the horizontal plane is 3°-30°, preferably 5°-20°.
[0049] Furthermore, to ensure that the gaseous isopropanol flowing back into the esterification vessel 1 has a high temperature and to guarantee the esterification reaction rate, a gas phase heater 9 is provided between the dehydration input end and the esterification vessel 1. The structure of the gas phase heater 9 is similar to that of the liquid phase heater 4. The gas phase heater 9 has a gas phase heating input end and a gas phase heating output end. The gas phase heating input end is connected to the esterification vessel 1 through a gas phase input pipe 91. The liquid phase heater 4 itself also has a temperature control device that can control the heating temperature, so that the heating temperature can be controlled within a preset range. In this embodiment, the set temperature of the gas phase heater is 100±5°C. A temperature measuring device 91 is installed on the gas phase input pipe 92. The temperature measuring device 91 is usually a thermometer. When the temperature in the esterification vessel 1 is measured to be 80°C, the gas phase heater 9 is turned on to start working. The gas phase heating output end is connected to the dehydration input end of the gas dehydration device 7 to heat the gaseous isopropanol and water flowing through the gas phase heater 9 to a predetermined temperature, so as to maintain the liquid phase mixture in the esterification vessel 1 at the optimal reaction temperature and guarantee the reaction rate.
[0050] Furthermore, to ensure the dehydration effect of isopropanol containing water, the gas dehydration device 7 in this embodiment is an inorganic molecular sieve pervaporation membrane device. The inorganic molecular sieve pervaporation membrane device is a conventional dehydration device. In this embodiment, the inorganic molecular sieve pervaporation membrane is of type NaA (Na indicates that Na+ ions are the main cations in the molecular sieve framework structure, and A indicates a specific crystal structure). Its specific structure can be found in [reference needed]. Figure 7 The inorganic molecular sieve pervaporation membrane device can be used individually, or multiple devices can be connected in series or parallel. It includes a shell and multiple molecular sieve membrane tubes inside the shell. These multiple molecular sieve membrane tubes have permeation spaces between them. The size of water molecules is approximately 0.28 nanometers, and the size of isopropanol molecules is approximately 0.48 nanometers. Multiple pores with a diameter of 0.4 nanometers are provided on the molecular sieve membrane tubes. When gaseous isopropanol and water pass through the molecular sieve membrane tubes, only water molecules can pass through the pores and enter the permeation space. A vacuum pump 71 is provided outside the shell, which is connected to the permeation space and creates a vacuum environment for the permeation space. A wastewater condenser 72 is provided between the vacuum pump 71 and the shell. The wastewater condenser 72 is sealed to the permeation space through a water outlet pipe 73. The permeated water molecules are collected by condensation in the wastewater condenser 72 under the attraction of the vacuum pump 71. The dehydrated gaseous isopropanol molecules enter the gas phase output pipe 81 along the molecular sieve membrane tubes, thereby obtaining dehydrated anhydrous isopropanol.
[0051] Furthermore, the gas dehydration device 7 is an inorganic molecular sieve pervaporation membrane device, which is also easy to clean later. After long-term use, the pores of the molecular sieve membrane tube are prone to blockage. At this time, high-temperature steam can be blown back into the permeation space of the inorganic molecular sieve pervaporation membrane device to ensure its normal operation.
[0052] Furthermore, the esterification reactor 1 is also connected to a sampling valve 5. When it is necessary to determine the completion status of the esterification reaction, the sampling valve 5 can be opened and a sample can be taken every half hour to determine the acidity of the sample. If the acid value is less than 0.5, it indicates that the esterification reaction has been completed.
[0053] Furthermore, to simplify the installation layout of each component, a four-way connector is installed at the fourth connection port 15 at the bottom of the esterification reactor 1. The four-way connector has four installation ports, one of which is connected to the fourth connection port 15, and the other three installation ports are connected to the feed valve 5, the discharge pipe 61, and the guide pipe 21, respectively.
[0054] Furthermore, the esterification vessel 1 also has a second connection port 13, which is connected to a condenser 101. The condenser 101 and the second connection port 13 are connected through a condenser input pipe 102. After the esterification reaction is completed, a small amount of isopropanol remains in the esterification vessel. At this time, the remaining isopropanol can be distilled off and condensed into a liquid phase in the condenser for easy collection and storage.
[0055] Furthermore, a self-regulating safety valve 10 is connected to the condenser input pipe 102. The self-regulating safety valve 10 is set with a predetermined pressure, usually 0.06 MPa. When the reaction pressure in the esterification reactor 1 is too high, the self-regulating safety valve 10 will automatically open and provide pressure relief protection. It should be noted that when the remaining isopropanol is distilled off, the self-regulating safety valve 10 is in a fully open state so that the isopropanol vapor can enter the condenser 101.
[0056] Furthermore, the esterification reactor 1 is also connected to a discharge pump 6, which is connected to the esterification reactor via a discharge pipe 61. After the esterification reaction is completed and the remaining isopropanol is distilled off, the circulation pump 2 can be turned off and the discharge pump 6 can be started to remove the generated fatty acid isopropanol.
[0057] Furthermore, the Venturi tube 3 and the esterification vessel 1, the delivery pipe 35 and the Venturi tube 3, and the gas phase output pipe 81 and the wide-diameter input section 31 of the Venturi tube 3 are all sealed and connected by flange structures. Taking the delivery pipe 35 and the Venturi tube 3 as an example, the outer end of the wide-diameter input section 31 of the Venturi tube 3 has a first flange ring, and the end of the delivery pipe 35 facing the Venturi tube 3 has a corresponding second flange ring. The outer diameter of the delivery pipe 35 matches the inner diameter of the second flange ring. The second flange ring is fitted onto the delivery pipe 35 and welded and fixed, thereby forming the insertion section. The first flange ring and the second flange ring are mated and locked with bolts to seal the delivery pipe 35 and the Venturi tube 3, while the insertion section is inserted into the narrow-diameter section 32. Taking the gas phase output pipe 81 and the wide-diameter input section 31 of the Venturi tube 3 as another example, the first connection port 12 has a flange, and the end of the gas phase output pipe 81 facing the first connection port 12 also has a flange. The two flanges correspond to each other and are locked with screws to form a sealed connection.
[0058] The present invention and its embodiments have been described above illustratively. This description is not restrictive, and the figures shown are only one embodiment of the present invention; the actual structure is not limited thereto. Therefore, if those skilled in the art are inspired by this description and design similar structures and embodiments without departing from the inventive spirit of the present invention, such designs should fall within the protection scope of the present invention.
Claims
1. A device for producing fatty acid isopropyl esters, characterized in that, include: Esterification vessel (1) is used to contain a liquid mixture containing fatty acids and isopropanol. When fatty acids react with isopropanol, the temperature of the liquid mixture rises, causing some isopropanol and water to be converted from the liquid phase to the gas phase. The circulating feed system includes a circulating pump (2) and a venturi tube (3). The circulating pump (2) is internally connected to the esterification vessel (1). The venturi tube (3) has a feed end and a discharge end. The feed end is connected to the circulating pump (2), and the discharge end is internally connected to the esterification vessel (1). The circulating pump (2) can guide part of the liquid phase mixture in the esterification vessel (1) into the venturi tube (3) and form a liquid phase jet that is accelerated and sprayed into the esterification vessel (1). The dehydration and re-reaction system includes a gas dehydration device (7), which has a dehydration input end and a dehydration output end. The dehydration input end is connected to the interior of the esterification vessel (1) to introduce gaseous isopropanol and water into the gas dehydration device (7); the dehydration output end is connected to a venturi tube (3). When the circulation guide system is working, the liquid jet forms a negative pressure in the venturi tube (3) to attract the dehydrated gaseous isopropanol back to the esterification vessel (1) to react with fatty acids again.
2. The fatty acid isopropyl ester preparation equipment according to claim 1, characterized in that: The venturi tube (3) includes a wide-diameter input section (31) and a wide-diameter output section (33), with a narrow-diameter section (32) integrally formed between the wide-diameter input section (31) and the wide-diameter output section (33); the end of the wide-diameter input section (31) is the feed end, the end of the wide-diameter output section (33) is the discharge end, and the dewatering output end is connected to the wide-diameter input section (31).
3. The fatty acid isopropyl ester preparation equipment according to claim 2, characterized in that: The circulating pump (2) is connected to the venturi tube (3) through the delivery pipe (35), and the end of the delivery pipe (35) facing the venturi tube (3) passes through the wide diameter input section (31) and is inserted into the narrow diameter section (32).
4. The fatty acid isopropyl ester preparation equipment according to claim 3, characterized in that: The part of the delivery pipe (35) inserted into the narrow diameter section (32) is called the insertion section, and the outer diameter of the insertion section is smaller than the inner diameter of the narrow diameter section (32).
5. The fatty acid isopropyl ester preparation equipment according to claim 1, characterized in that: A liquid phase heater (4) is provided between the circulating pump (2) and the venturi tube (3). The liquid phase heater (4) has a liquid phase heating input end and a liquid phase heating output end. The liquid phase heating input end is connected to the circulating pump (2), and the liquid phase heating output end is connected to the feed end of the venturi tube (3) to heat part of the liquid phase mixture flowing through the liquid phase heater (4) to a predetermined temperature.
6. The fatty acid isopropyl ester preparation equipment according to claim 1, characterized in that: The dehydration output end is connected to the Venturi tube (3) through a gas phase output pipe (81). A self-controlled pressure valve (8) that can be opened at a predetermined pressure is installed on the gas phase output pipe (81). When the pressure in the gas phase output pipe (81) is less than the predetermined pressure value, the self-controlled pressure valve (8) closes to keep the pressure in the esterification kettle (1) stable. When the pressure in the gas phase output pipe (81) is greater than or equal to the predetermined pressure value, the self-controlled pressure valve (8) opens to allow the dehydrated gas phase isopropanol to pass through.
7. The fatty acid isopropyl ester preparation equipment according to claim 1, characterized in that: The Venturi tube (3) is connected to the interior of the esterification vessel (1) along the tangential direction of the esterification vessel (1).
8. The fatty acid isopropyl ester preparation equipment according to claim 7, characterized in that: The venturi tube (3) extends obliquely downwards, and the position of the feed end is higher than the position of the discharge end.
9. The fatty acid isopropyl ester preparation equipment according to claim 1, characterized in that: A gas phase heater (9) is provided between the dehydration input end and the esterification vessel (1). The gas phase heater (9) has a gas phase heating input end and a gas phase heating output end. The gas phase heating input end is connected to the esterification vessel (1), and the gas phase heating output end is connected to the dehydration input end of the gas dehydration device (7) to heat the gas phase isopropanol and water flowing through the gas phase heater (9) to a predetermined temperature.
10. The fatty acid isopropyl ester preparation equipment according to claim 1, characterized in that: The gas dehydration device (7) is an inorganic molecular sieve pervaporation membrane device.