System and method for preparing 1,3-propanediol
Patent Information
- Application Number
- PCT/CN2025/108796
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2025-03-26
- Filing Date
- 2025-07-16
- Publication Date
- 2026-10-01
Smart Images
Figure CN2025108796_01102026_PF_FP_ABST
Abstract
Description
A system and method for preparing 1,3-propanediol Technical Field This invention relates to the field of 1,3-propanediol preparation technology, and more specifically, to a system and method for preparing 1,3-propanediol. Background Technology 1,3-Propanediol is an important chemical raw material and a key ingredient in the synthesis of polypropylene terephthalate (PTT). PTT is a high-performance polyester fiber widely used in the textile and apparel industries. It is commonly used as a raw material for polyester polyols, an initiator for polyether polyols, and a chain extender for polyurethanes, in the production of high-performance polyurethane materials. Simultaneously, 1,3-Propanediol can be used in the food industry as a humectant, solvent, and emulsifier, extending shelf life and maintaining texture and moisture. It can also be used as an organic solvent in the lubricant and antifreeze industries. In related technologies, the preparation process of 1,3-propanediol is mostly prepared by the hydrogenation of acrolein hydration. Currently, the hydrogenation reaction process mostly uses a fixed-bed reactor, which requires periodic shutdowns to replace the catalyst during production, resulting in high energy consumption and economic losses and safety risks. In view of this, the present invention is hereby proposed. Summary of the Invention The primary objective of this invention is to provide a system for preparing 1,3-propanediol. This system employs a slurry bed for hydrogenation, allowing for the real-time addition of the catalyst required for the hydrogenation reaction via a fourth feed line during production. This solves the problem of having to shut down the plant to replace the catalyst in a fixed-bed reactor. Furthermore, this system, through a first enhanced mass transfer unit located in the hydration reactor and a second enhanced mass transfer unit located in the hydrogenation reactor, can increase the phase-interface mass transfer area between the raw materials in the acrolein hydration and hydrogenation reactions, thereby improving the raw material conversion rate and reducing the energy consumption required for the reaction, which helps to increase production profits. A second objective of the present invention is to provide a method for preparing 1,3-propanediol, which, by employing the above-described system, enables the efficient production of 1,3-propanediol. In order to achieve the above-mentioned objectives of the present invention, the following technical solution is adopted: This invention provides a system for preparing 1,3-propanediol, comprising: a first feed line, a second feed line, and a third feed line. Feed line, fourth feed line, hydration reactor, rotary extractor and hydrogenation reactor; The first feed line is used to convey a mixed solution of acrolein, homogeneous catalyst, and polymerization inhibitor. The first feed line is connected to... The hydration reactor is connected; The second feed line is used to transport deionized water. The hydration reactor is equipped with a first enhanced mass transfer unit. The second feed line is connected to the first enhanced mass transfer unit; The outlet of the hydration reactor is connected to the rotating disc extraction tower, and the aqueous phase outlet of the rotating disc extraction tower is connected via a delivery pipeline. The bottom of the hydrogenation reactor; The third feed line is used to transport hydrogen gas, and the hydrogenation reactor is equipped with a second enhanced mass transfer unit. The material pipeline is connected to the second enhanced mass transfer unit; The fourth feed line is used to transport the hydrogenation reaction catalyst, and the fourth feed line is connected to the transport line; The hydrogenation reactor is a slurry bed reactor; the material outlet of the hydrogenation reactor is vertically higher than the second enhanced reactor. The mass transfer unit, wherein the material outlet is vertically lower than the liquid level inside the hydrogenation reactor; A baffle is installed inside the hydrogenation reactor near the material outlet, with the top of the baffle vertically higher than the material outlet. The baffle is positioned below the liquid level in the hydrogenation reactor; the bottom of the baffle extends downwards at an angle close to the side wall of the hydrogenation reactor to form an extension, and there is a gap between the bottom of the extension and the side wall of the hydrogenation reactor. In the above scheme, acrolein, a homogeneous catalyst, and a polymerization inhibitor are mixed in the first feed line. The homogeneous catalyst catalyzes the hydration reaction, while the polymerization inhibitor prevents acrolein dimerization, improving product selectivity. This scheme, by pre-mixing the homogeneous catalyst and polymerization inhibitor into the acrolein before the reaction, helps ensure uniform distribution of the catalyst and inhibitor in the hydration reactor, thus facilitating better catalytic and polymerization-inhibiting effects, increasing the conversion rate of the reaction feedstock, and reducing side reactions. By setting up a first enhanced mass transfer unit in the hydration reactor, deionized water can be dispersed into micron-sized droplets, thereby increasing the phase-interface mass transfer area between deionized water and acrolein. This helps improve the efficiency of the hydration reaction and the feedstock conversion rate, and can, to some extent, reduce the temperature and pressure requirements of the hydration reaction, thus helping to reduce reaction energy consumption. The hydrogenation reactor in this scheme is a slurry-bed reactor, and a hydrogenation reaction catalyst is added to the hydrogenation reactor through a fourth feed line. The catalyst for the hydrogenation reaction can be replaced in real time during production, thus solving the problem of fixed-bed reactors requiring shutdown for catalyst replacement. By installing a second enhanced mass transfer unit in the hydrogenation reactor, hydrogen can be dispersed and broken into micron-sized microbubbles, thereby increasing the phase-interface mass transfer area between hydrogen and 3-hydroxypropanal. This helps to improve the reaction efficiency of the hydrogenation reaction, the conversion rate of 3-hydroxypropanal, and the selectivity of 1,3-propanediol, and can also reduce the temperature and pressure requirements of the hydrogenation reaction to a certain extent, thus helping to reduce reaction energy consumption. By installing a baffle near the material outlet in the hydrogenation reactor, the baffle and the side wall of the hydrogenation reactor can form an internal settling tank. The reaction liquid in the hydrogenation reactor flows into the internal settling tank for sedimentation. The supernatant is output through the material outlet, while the turbid liquid flows back into the hydrogenation reactor through the gap between the bottom of the extension and the side wall of the hydrogenation reactor to continue participating in the reaction. This can improve the purity of the product output from the material outlet and the utilization rate of the catalyst, which helps to save costs. Preferably, the first enhanced mass transfer unit includes a first enhanced mass transfer device and a second enhanced mass transfer device, and the second feed pipeline is connected to the first enhanced mass transfer device and the second enhanced mass transfer device respectively. Both the first and second enhanced mass transfer devices have outlets at their upper and lower ends. The number of upper outlets is less than the number of lower outlets, and the number of upper outlets of the second enhanced mass transfer device is greater than the number of lower outlets. The first enhanced mass transfer device is vertically positioned above the second enhanced mass transfer device, and the first enhanced mass transfer device is... The second enhanced mass transfer device is staggered in the vertical direction. In the above scheme, both enhanced mass transfer devices adopt a funnel-shaped structure with multiple outlets at one end and fewer outlets at the other. This allows for a more rational distribution of the output microdroplets. Furthermore, by staggering the first and second enhanced mass transfer devices vertically, the lower outlet of the first enhanced mass transfer device and the upper outlet of the second enhanced mass transfer device are interleaved. This arrangement avoids collisions between the two microdroplet streams, preventing liquid dead zones. The microdroplets ejected from the two enhanced mass transfer devices can agitate the reaction liquid within the hydration reactor. This not only ensures a uniform distribution of microdroplets, further increasing the mass transfer area and the contact area between the reactants, thus improving reaction efficiency, but also ensures a uniform distribution of the homogeneous catalyst and polymerization inhibitor in the reaction liquid, guaranteeing the catalytic effect of the homogeneous catalyst and the polymerization inhibitor's inhibition effect. This further contributes to improving the reaction efficiency of the hydration reaction. Preferably, the first feed line has a first outlet and a second outlet, the first outlet is located above the second outlet in the vertical direction, and both the first outlet and the second outlet are located between the first enhanced mass transfer device and the second enhanced mass transfer device in the vertical direction. The first outlet is connected to the side wall of the hydration reactor that is farther away from the first enhanced mass transfer device. The two outlets are connected to the side wall of the hydration reactor that is farther away from the second enhanced mass transfer device. In the above scheme, both outlets of the first feed pipe are located between the two enhanced mass transfer devices. It can be understood that there are a large number of micro-droplets between the two enhanced mass transfer devices. This method of directly supplementing acrolein between the two enhanced mass transfer devices can ensure the stable progress of the reaction. In addition, by connecting the first outlet to the side wall of the hydration reactor that is farther away from the first enhanced mass transfer device, and the second outlet to the side wall of the hydration reactor that is farther away from the second enhanced mass transfer device, the power of the material output from the two outlets and the power of the micro-droplets output from the two enhanced mass transfer devices can be used to agitate the reaction liquid between the two enhanced mass transfer devices. This can make the micro-droplets, homogeneous catalyst, and polymerization inhibitor evenly distributed, thereby helping to improve the hydration reaction efficiency. Preferably, the second enhanced mass transfer unit includes a third enhanced mass transfer device and a fourth enhanced mass transfer device, and the third feed pipeline is connected to the third enhanced mass transfer device and the fourth enhanced mass transfer device respectively; Both the third and fourth enhanced mass transfer devices have outlets at their upper and lower ends. The third enhanced mass transfer device... The number of upper outlets is less than the number of lower outlets, and the number of upper outlets of the fourth enhanced mass transfer device is greater than the number of lower outlets. The third enhanced mass transfer device is vertically positioned above the fourth enhanced mass transfer device, and the third enhanced mass transfer device is... The fourth enhanced mass transfer device is staggered in the vertical direction. In the above scheme, both enhanced mass transfer devices adopt a funnel-shaped structure with multiple outlets at one end and fewer outlets at the other. This allows for a more rational distribution of the output microbubbles within the hydrogenation reactor. Furthermore, by staggering the third and fourth enhanced mass transfer devices vertically, the lower outlet of the third enhanced mass transfer device and the upper outlet of the fourth enhanced mass transfer device are interleaved. This arrangement avoids collisions between the two microbubble streams, preventing liquid dead zones. The microbubbles ejected from the two enhanced mass transfer devices can also agitate the reaction liquid within the hydrogenation reactor. This not only ensures uniform distribution of microbubbles, further increasing the mass transfer area and the contact area between reactants, thus improving reaction efficiency, but also ensures uniform distribution of the hydrogenation catalyst within the reaction liquid, guaranteeing the catalyst's catalytic effect. This further contributes to improving the reaction efficiency of the hydrogenation reaction. Preferably, the system further includes a first circulation pipeline, the inlet of which is connected to the bottom of the hydrogenation reactor, and the outlet of which is connected to the side wall of the hydrogenation reactor that is farther away from the fourth enhanced mass transfer device; the outlet of the first circulation pipeline is located between the third enhanced mass transfer device and the fourth enhanced mass transfer device. In the above scheme, the first circulation pipeline can circulate the reaction liquid at the bottom of the hydrogenation reactor to the two enhanced mass transfer devices. This method can stir the bottom of the hydrogenation reactor and prevent the catalyst from depositing at the bottom. Preferably, the system further includes a second circulation pipeline; the inlet of the second circulation pipeline is connected to the side wall of the hydrogenation reactor near the baffle and the inlet of the second circulation pipeline is lower than the bottom of the extension in the vertical direction; the outlet of the second circulation pipeline is connected to the side wall of the hydrogenation reactor farther from the third enhanced mass transfer device; the outlet of the second circulation pipeline is located between the third enhanced mass transfer device and the fourth enhanced mass transfer device. In the above scheme, the second circulation pipeline can directly input the turbid liquid containing a high concentration of catalyst obtained by sedimentation in the built-in sedimentation tank into the space between the two enhanced mass transfer devices, and achieve uniform dispersion by the stirring of the microbubble flow in the two enhanced mass transfer devices, which helps to further improve the utilization rate and catalytic effect of the catalyst. Preferably, the outlet of the first circulation pipeline is located vertically below the outlet of the second circulation pipeline. This arrangement allows the two liquid streams output from the two circulation pipelines to work synergistically with the microbubble streams output from the two enhanced mass transfer devices to stir the reaction solution, thereby improving the stirring effect on the reaction solution and thus increasing the uniformity of the distribution of microbubbles and catalyst within the reaction solution. Preferably, the hydrogenation reactor is provided with multiple baffles, which are staggered and located vertically between the baffles and the second enhanced mass transfer unit. Preferably, the baffles are inclined downwards away from the sidewall of the hydrogenation reactor. This design, by staggering the multiple baffles, reduces the flow velocity of the upper reaction liquid, promotes catalyst sedimentation within the reaction liquid, and thus reduces the purity of the product output from the material outlet. In a further embodiment, by tilting the baffles downwards, the sedimented catalyst can flow back into the reaction liquid below along the baffles, preventing catalyst accumulation. Preferably, the system further includes a settling tank and a filter; the material outlet is connected to the settling tank, and the settling tank is connected to the filter; the filter is equipped with an arc-shaped filter cloth; the arc-shaped filter cloth divides the internal chamber of the filter into a filtration chamber and a filtrate chamber, the filtrate chamber is connected to the product pipeline, and the sidewall of the filtration chamber is connected to the hydrogenation reactor; preferably, there are two filters, and the two filters are arranged in parallel; preferably, a guide plate is provided at the inlet of the filter, and the guide plate extends downward at an angle close to the arc-shaped filter cloth. In this scheme, the filter cloth adopts a 1 / 4 arc design, which is more conducive to the recovery of catalyst and can effectively prevent catalyst from clogging on the filter cloth; in a further scheme, the number of filters is set to two, and the two filters can adopt an open and closed application mode to avoid shutdown due to filter cleaning, which helps to increase production efficiency; in a further scheme, a guide plate is provided in the filter, which can guide and buffer, and can prevent the coarse product entering the filter from directly impacting the arc-shaped filter cloth, ensuring the filtration effect of the arc-shaped filter cloth. Preferably, the oil phase outlet of the rotary disc extractor is connected to the distillation column; both the bottom and top outlets of the distillation column are connected to the first feed line, and the middle section outlet of the distillation column is connected to the rotary disc extractor. In this configuration, the aqueous phase containing 3-hydroxypropionaldehyde separated from the rotary disc extractor flows from the bottom of the column into the hydrogenation reactor for hydrogenation, while the oil phase containing homogeneous catalyst and unreacted acrolein flows from the top of the column into the distillation column for distillation separation. The acrolein produced at the top of the distillation column flows into the hydration reactor for recycling, the extractant produced in the middle section flows into the extractor for recycling, and the homogeneous catalyst produced at the bottom of the column flows into the hydration reactor for recycling. The recycling of materials can significantly improve product yield, and the recovered raw materials have no adverse effects on the reaction process. It will be understood by those skilled in the art that the enhanced mass transfer device used in this invention has been reflected in the inventors' prior patents, such as patents with application numbers CN201610641119.6, CN201610641251.7, CN201710766435.0, CN106187660A, CN105903425A, CN205833127U and CN207581700U. The prior patent CN201610641119.6 details the specific product structure and working principle of a micron-sized bubble generator (i.e., a bubble breaker). This application document states that "the micron-sized bubble generator includes a main body and a secondary breaking component. The main body has a cavity, and an inlet communicating with the cavity is provided on the main body. The first and second ends of the cavity are both open, and the cross-sectional area of the cavity decreases from the middle of the cavity towards the first and second ends. The secondary breaking component is located at at least one of the first and second ends of the cavity, with a portion of the secondary breaking component located within the cavity. A ring-shaped channel is formed between the secondary breaking component and the open through-holes at both ends of the cavity. The micron-sized bubble generator also includes an air inlet pipe and a liquid inlet pipe." From the specific structure disclosed in this application document, its specific working principle can be understood as follows: liquid enters the micron-sized bubble generator tangentially through the liquid inlet pipe, rotates at ultra-high speed, and cuts the gas, causing the gas bubbles to break into micron-sized microbubbles, thereby increasing the mass transfer area between the liquid and gas phases. Moreover, the micron-sized bubble generator in this patent is a pneumatic bubble breaker. Furthermore, prior patent 201610641251.7 describes a primary bubble breaker with a circulating liquid inlet, a circulating gas inlet, and a gas-liquid mixture outlet, while a secondary bubble breaker connects the feed inlet to the gas-liquid mixture outlet. This indicates that both bubble breakers require a gas-liquid mixture to enter. Additionally, as shown in the accompanying drawings, the primary bubble breaker primarily utilizes the circulating liquid as its power source, thus classifying it as a hydraulically driven enhanced reactor. The secondary bubble breaker simultaneously introduces the gas-liquid mixture into an elliptical rotating sphere for rotation, thereby achieving bubble breakage during rotation. Therefore, the secondary bubble breaker is actually a gas-liquid linked bubble breaker. In fact, both hydraulically driven and gas-liquid linked bubble breakers are specific forms of bubble breakers. However, the enhanced mass transfer device used in this invention is not limited to these forms; the specific structure of the bubble breaker described in the prior patent is merely one possible form that this invention can employ. Furthermore, prior patent 201710766435.0 describes "the principle of a bubble breaker is that a high-speed jet achieves mutual collision of gases"; and prior patent CN106187660 also describes the specific structure of a bubble breaker, as detailed in the specification.
[0031] -
[0041] The section and the accompanying diagram provide a detailed explanation of the working principle of the bubble breaker S-2. The top of the bubble breaker is the liquid phase inlet, and the side is the gas phase inlet. The liquid phase coming in from the top provides the entrainment force, thereby achieving the effect of crushing into ultrafine bubbles. As can be seen in the diagram, the bubble breaker has a conical structure, with the upper diameter being larger than the lower diameter, which is also to allow the liquid phase to provide better entrainment force. Because the bubble breaker was newly developed in the early stages of the prior patent application, it was initially named a micron bubble generator (CN201610641119.6), etc. With continuous technological improvements, it was later renamed a bubble breaker. The enhanced mass transfer device in this invention is equivalent to the previous micron bubble generator, micro-interface generator, etc., only with different names. In summary, the enhanced mass transfer device of this invention belongs to the prior art. The present invention also provides a method for preparing 1,3-propanediol, wherein the method uses the system of any of the above embodiments to prepare 1,3-propanediol. Compared with the prior art, the beneficial effects of the present invention are as follows: 1. Acrolein, a homogeneous catalyst, and a polymerization inhibitor are mixed in the first feed line, wherein the homogeneous catalyst is used to catalyze hydration. The reaction occurs, and the polymerization inhibitor is used to prevent acrolein from undergoing dimerization and improve product selectivity. This scheme helps to ensure that the homogeneous catalyst and polymerization inhibitor are evenly distributed in the hydrated reactor by mixing the homogeneous catalyst and polymerization inhibitor into acrolein before the reaction, thereby helping to better exert the catalytic and polymerization inhibition effects, improve the conversion rate of the reaction raw materials, and reduce the occurrence of side reactions. 2. By installing a first enhanced mass transfer unit in the hydration reactor, deionized water can be dispersed into micron-sized microdroplets. This increases the mass transfer area at the phase boundary between deionized water and acrolein, which helps to improve the efficiency of the hydration reaction and the conversion rate of raw materials. It can also reduce the temperature and pressure requirements of the hydration reaction to a certain extent, thereby helping to reduce the energy consumption of the reaction. 3. The hydrogenation reactor in this scheme adopts a slurry bed reactor, and hydrogenation reagents are added to the hydrogenation reactor through a fourth feed pipeline. The catalyst can be replaced in real time during the production process, thus solving the problem of having to stop the production line to replace the catalyst in a fixed bed. 4. By installing a second enhanced mass transfer unit inside the hydrogenation reactor, hydrogen gas can be dispersed and broken into micron-sized microbubbles. This increases the phase-to-phase mass transfer area between hydrogen and 3-hydroxypropanal, which helps to improve the reaction efficiency of hydrogenation, the conversion rate of 3-hydroxypropanal, and the selectivity of 1,3-propanediol. It can also reduce the temperature and pressure requirements of hydrogenation to a certain extent, thereby helping to reduce reaction energy consumption. 5. By installing a baffle near the material outlet inside the hydrogenation reactor, the baffle and the side wall of the hydrogenation reactor can form an integrated structure. The reaction liquid in the hydrogenation reactor flows into the built-in settling tank for settling. The supernatant is output through the material outlet, while the turbid liquid flows back into the hydrogenation reactor through the gap between the bottom of the extension and the side wall of the hydrogenation reactor to continue participating in the reaction. This can improve the purity of the product output from the material outlet and the utilization rate of the catalyst, which helps to save costs. Attached Figure Description Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings: Figure 1 shows a schematic diagram of the system for preparing 1,3-propanediol according to Example 1 of the present invention; Figure 2 shows the liquid flow direction between the first enhanced mass transfer device and the second enhanced mass transfer device in the hydration reactor of Embodiment 1 of the present invention. Schematic diagram; Figure 3 shows a schematic diagram of the hydrogenation reactor of Embodiment 1 of the present invention; Figure 4 shows the liquid flow direction between the third and fourth enhanced mass transfer devices in the hydrogenation reactor of Embodiment 1 of the present invention. Schematic diagram; Figure 5 shows a schematic diagram of the filter structure of Embodiment 1 of the present invention. In the diagram: 1. Hydration reactor; 2. First enhanced mass transfer device; 3. First feed line; 4. Second feed line; 5. Second enhanced mass transfer device; 6. Rotary extraction column; 7. Distillation column; 8. Hydrogenation reactor; 9. Fourth feed line; 10. Settling tank; 11. Filter; 12. Third feed line; 13. First circulation line; 14. Second circulation line; 15. Baffle; 16. Extension section; 17. Baffle; 18. Fourth enhanced mass transfer device; 19. Third enhanced mass transfer device; 20. Arc-shaped filter cloth; 21. Guide plate; 22. Conveying line. Detailed Implementation The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings and specific embodiments. However, those skilled in the art will understand that the embodiments described below are some embodiments of the present invention, but not all embodiments, and are only used to illustrate the present invention, and should not be regarded as limiting the scope of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall be followed. Where the manufacturers of reagents or instruments are not specified, they are all conventional products that can be purchased commercially. In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance. In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances. To more clearly illustrate the technical solutions in this invention, the following description is provided in the form of specific embodiments. Example 1 Referring to Figures 1-5, this embodiment provides a system for preparing 1,3-propanediol, the system comprising: a first feed Pipeline 3, second feed pipeline 4, third feed pipeline 12, fourth feed pipeline 9, hydration reactor 1, rotating disc extractor 6, and hydrogenation reactor 8; the first feed pipeline 3 is used to transport a mixed solution of acrolein, homogeneous catalyst, and polymerization inhibitor, and is connected to the hydration reactor 1; the second feed pipeline 4 is used to transport deionized water, and the hydration reactor 1 is equipped with a first enhanced mass transfer unit, which is connected to the first enhanced mass transfer unit; the outlet of the hydration reactor 1 is connected to the rotating disc extractor 6, and the aqueous phase outlet of the rotating disc extractor 6 is connected to the bottom of the hydrogenation reactor 8 via a conveying pipeline 22; the third feed pipeline 12 is used to transport hydrogen, and the hydrogenation reactor 8 is equipped with a second enhanced mass transfer unit. The mass transfer unit has a third feed line 12 connected to the second enhanced mass transfer unit; a fourth feed line 9 is used to transport the hydrogenation reaction catalyst and is connected to the conveying line 22; the hydrogenation reactor 8 is a slurry bed reactor; the material outlet of the hydrogenation reactor 8 is vertically higher than the second enhanced mass transfer unit and vertically lower than the liquid level inside the hydrogenation reactor 8; a baffle 17 is installed inside the hydrogenation reactor 8 near the material outlet, the top of the baffle 17 is vertically higher than the material outlet and lower than the liquid level inside the hydrogenation reactor 8; the bottom of the baffle 17 extends downward at an angle near the side wall of the hydrogenation reactor 8 to form an extension 16, and there is a gap between the bottom of the extension 16 and the side wall of the hydrogenation reactor 8. Homogeneous catalysts, polymerization inhibitors, and hydrogenation catalysts can be selected as needed. In this embodiment, the homogeneous catalyst can be an N-alkyl amino acid, and the amount of homogeneous catalyst added can be 5-15% of the mass of the hydrated reaction solution. The pressure of the hydration reaction can be 0-0.5 MPa (gauge pressure), the temperature can be 30-60℃, and the time can be 2-4 h. The amount of acrolein added in the hydration reaction is 5-25% of the mass of the hydrated reaction solution. The pressure of the hydrogenation reaction can be 2-5 MPa (gauge pressure), the temperature can be 40-100℃, and the space velocity can be 1-5 h⁻¹. -1 . The polymerization inhibitor can be hydroquinone, and the amount of hydroquinone added can be 0-0.1% of the mass of the hydrated reaction solution. In the hydration reaction, acrolein is prone to dimerization, which reduces selectivity. At the same time, the dimer has a certain interaction with the product, making it difficult to separate and affecting the product quality. Adding a trace amount of polymerization inhibitor can prevent acrolein dimerization. In the subsequent extraction operation, a small portion of the polymerization inhibitor enters the oil phase and enters the N-alkyl amino acid stream in the bottom of the column during the oil phase separation process. It is then recovered to the hydration reactor 1 along with the stream. The remaining polymerization inhibitor enters the hydrogenation reactor 8 with the aqueous phase, but the presence of the polymerization inhibitor has no adverse effect on the hydrogenation reaction. The hydrogenation reaction catalyst can be a powdered supported noble metal catalyst, with the noble metal selected from nickel, palladium, rhodium or platinum, and the support being alumina, titanium oxide or silicon oxide. The noble metal content in the supported noble metal catalyst is 5-30 wt%. In this embodiment, acrolein, homogeneous catalyst, and polymerization inhibitor can be pre-mixed and then fed into the hydration reactor 1 via the first feed pipe 3. It is understood that water pumps can be installed on the pipes to ensure the flow of materials within each pipe; details are omitted here. In this embodiment, a built-in settling tank can be formed between the baffle 17 and the side wall of the hydration reactor 1. The volume of this tank can be 1 / 20 to 1 / 10 of the volume of the hydrogenation reactor 8, the height can be 1 / 5 to 3 / 5 of the height of the hydrogenation reactor 8, and the width can be 1 / 10 to 1 / 5 of the width of the hydrogenation reactor 8. The height of the lower turbid liquid is 1 / 10 to 1 / 5 of the tank height. The built-in settling tank allows some of the powdered catalyst to settle in the tank, reducing the amount of catalyst to be recovered later and saving costs. In this embodiment, the rotating disc extraction tower 6 has 3-6 theoretical plates, the extraction method is countercurrent extraction, the extractant is at least one of methyl tert-butyl ether, diethyl ether and benzene, the oil-water mass ratio is 1.5-5:1, and the extraction temperature is 25-40℃. In this embodiment, as shown in Figure 1, the oil phase outlet of the rotary extractor 6 is connected to the distillation column 7; both the bottom and top outlets of the distillation column 7 are connected to the first feed line 3, and the middle outlet of the distillation column 7 is connected to the rotary extractor 6. The aqueous phase containing 3-hydroxypropionaldehyde separated from the rotary extractor 6 flows into the hydrogenation reactor 8 for hydrogenation reaction, while the oil phase containing N-alkyl amino acids and unreacted acrolein flows into the distillation column 7 for distillation separation. The acrolein produced at the top of the distillation column 7 flows into the hydration reactor 1 for recycling, the extractant produced in the middle section flows into the extractor for recycling, and the N-alkyl amino acids produced at the bottom of the column flow into the hydration reactor 1 for recycling. The recycling of materials can significantly improve the product yield, and the recovered raw materials have no adverse effects on the reaction process. Referring again to Figure 1, in this embodiment, the first enhanced mass transfer unit includes a first enhanced mass transferor 2 and a second enhanced mass transferor 5. A second feed pipe 4 connects to both the first enhanced mass transferor 2 and the second enhanced mass transferor 5. Both the first and second enhanced mass transferors 2 and 5 have outlets at their upper and lower ends. The number of outlets at the upper end of the first enhanced mass transferor 2 is less than the number of outlets at the lower end, and the number of outlets at the upper end of the second enhanced mass transferor 5 is greater than the number of outlets at the lower end. The first enhanced mass transferor 2 is vertically positioned above the second enhanced mass transferor 5, and the first and second enhanced mass transferors 2 and 5 are staggered vertically. In this embodiment, the enhanced mass transferors used (including the first enhanced mass transferor 2, the second enhanced mass transferor 5, the third enhanced mass transferor 19, and the fourth enhanced mass transferor 18) are all funnel-shaped, with a length ratio of 5:2 between their two ends. Referring again to Figure 1, in this embodiment, the first feed pipe 3 has a first outlet and a second outlet. The first outlet is located vertically above the second outlet, and both the first and second outlets are vertically located between the first enhanced mass transfer device 2 and the second enhanced mass transfer device 5. The first outlet is connected to the side wall of the hydration reactor 1 that is farther from the first enhanced mass transfer device 2, and the second outlet is connected to the side wall of the hydration reactor 1 that is farther from the second enhanced mass transfer device 5. In this case, as shown in Figure 2, the reaction liquid between the two enhanced mass transfer devices can be agitated clockwise by the power of the material output from the two outlets and the power of the microdroplets output from the two enhanced mass transfer devices, thereby improving the uniformity of the catalyst and microdroplet distribution within the reaction liquid. Referring again to Figure 1, the second enhanced mass transfer unit includes a third enhanced mass transferor 19 and a fourth enhanced mass transferor 18. The third feed pipe 12 is connected to the third enhanced mass transferor 19 and the fourth enhanced mass transferor 18 respectively. Both the third enhanced mass transferor 19 and the fourth enhanced mass transferor 18 have outlets at their upper and lower ends. The number of outlets at the upper end of the third enhanced mass transferor 19 is less than the number of outlets at the lower end, and the number of outlets at the upper end of the fourth enhanced mass transferor 18 is greater than the number of outlets at the lower end. The third enhanced mass transferor 19 is arranged vertically above the fourth enhanced mass transferor 18, and the third enhanced mass transferor 19 and the fourth enhanced mass transferor 18 are staggered in the vertical direction. Referring to Figures 1 and 3, the system also includes a first circulation pipeline 13. The inlet of the first circulation pipeline 13 is connected to the bottom of the hydrogenation reactor 8, and the outlet is connected to the side wall of the hydrogenation reactor 8 that is farther away from the fourth enhanced mass transfer device 18. The outlet of the first circulation pipeline 13 is located between the third enhanced mass transfer device 19 and the fourth enhanced mass transfer device 18. The reaction liquid at the bottom of the hydrogenation reactor 8 is pumped into the space between the third enhanced mass transfer device 19 and the fourth enhanced mass transfer device 18 via the first circulation pipeline 13. Referring to Figures 1 and 3, the system also includes a second circulation pipe 14; the inlet of the second circulation pipe 14 is connected to the side wall of the hydrogenation reactor 8 near the baffle 17, and the inlet of the second circulation pipe 14 is vertically lower than the bottom of the extension 16; the outlet of the second circulation pipe 14 is connected to the side wall of the hydrogenation reactor 8 farther from the third enhanced mass transfer device 19; the outlet of the second circulation pipe 14 is located between the third enhanced mass transfer device 19 and the fourth enhanced mass transfer device 18. The turbid liquid settled in the settling tank is pumped into the space between the third enhanced mass transfer device 19 and the fourth enhanced mass transfer device 18 via the second circulation pipe 14. In this embodiment, the outlet of the first circulation pipe 13 is located vertically below the outlet of the second circulation pipe 14. As shown in Figure 4, in this case, the two liquid streams output from the two circulation pipes and the microbubble streams output from the two enhanced mass transfer devices can stir the reaction liquid in a counterclockwise direction. Referring to Figures 1 and 3, the hydrogenation reactor 8 is equipped with multiple baffles 15, which are staggered and located vertically between the baffle 17 and the second enhanced mass transfer unit. The baffles 15 are inclined downwards away from the sidewall of the hydrogenation reactor 8. In this embodiment, the inlet of the second circulation pipeline 14 is higher than the baffles 15 in the vertical direction. Referring to Figures 1 and 5, the system also includes a settling tank 10 and a filter 11; the material outlet is connected to the settling tank 10, and the settling tank 10 is connected to the filter 11. In this embodiment, there are two filters 11, which are connected in parallel. The two filters 11 can be used in an open-closed mode to avoid shutdown due to cleaning the filters 11. As shown in Figure 5, an arc-shaped filter cloth 20 is installed inside the filter 11. The arc-shaped filter cloth 20 divides the internal chamber of the filter 11 into a filtration chamber and a filtrate chamber. The filtrate chamber is connected to the product pipeline, and the side wall of the filtration chamber is connected to the hydrogenation reactor 8. A guide plate 21 is installed at the inlet of the filter 11, and the guide plate 21 extends downward at an angle close to the arc-shaped filter cloth 20. The reacted material flows from bottom to top in the hydrogenation reactor 8 and flows into the settling tank 10 from the material outlet for sedimentation. The supernatant is the product 1,3-propanediol, and the turbid liquid is filtered and separated by the filter 11. The filtered solid catalyst is returned to the hydrogenation reactor 8 for recycling, and the filtrate is the product 1,3-propanediol. This embodiment also provides a method for preparing 1,3-propanediol, which uses the above-described system to prepare 1,3-propanediol. The method specifically includes the following steps: First, deionized water is passed into the first enhanced mass transfer device 2 and the second enhanced mass transfer device 5 in the hydration reactor 1, and propylene is then introduced into the reactor. Aldehydes, N-alkyl amino acids, and hydroquinone are added to hydration reactor 1 at concentrations of 5-25%, 5-15%, and 0-0.1% of the hydrated reaction solution, respectively. The hydration reaction is carried out under conditions of 0-0.5 MPa (gauge pressure), 30-60°C, and 2-4 hours to produce 3-hydroxypropanal. The reacted material flows upwards in hydration reactor 1 and flows from the top into rotating disc extraction column 6 for extraction separation. At least one of methyl tert-butyl ether, diethyl ether, and benzene is selected as the extractant. The theoretical plate number of the extraction column is 3-6, the extraction method is countercurrent extraction, the oil-to-water mass ratio is 1.5-5:1, and the extraction temperature is 25-40°C. The separated aqueous phase containing 3-hydroxypropanal flows from the bottom of the column into hydrogenation reactor 8 for hydrogenation, while the oil phase containing N-alkyl amino acids and unreacted acrolein flows from the top of the column into distillation column 7 for distillation separation. The acrolein produced at the top of distillation column 7 flows into hydration reactor 1 for recycling, the extractant produced in the middle section flows into extraction column for recycling, and the N-alkyl amino acids produced at the bottom of the column flow into hydration reactor 1 for recycling. Then, the powdered supported noble metal catalyst is loaded into the hydrogenation reactor 8, and hydrogen gas is introduced into the micro-interface enhancement unit of the hydrogenation reactor 8. The pressure of the hydrogenation reaction is controlled at 2-5 MPa (gauge pressure), the temperature at 40-100℃, and the space velocity at 1-5 h⁻¹. -1 The hydrogenation reaction produces 1,3-propanediol. The reacted material flows from bottom to top in the hydrogenation reactor 8 and flows from the top of the tower into the settling tank 10 for precipitation. The supernatant is the product 1,3-propanediol, and the turbid liquid is filtered and separated. The filtered solid catalyst is returned to the hydrogenation reactor 8 for recycling, and the filtrate is the product 1,3-propanediol. In this embodiment, the specific process for preparing 1,3-propanediol is as follows: 6.8 kg of deionized water is introduced into the first enhanced mass transfer unit of the hydration reactor, along with 1.5 kg of acrolein and 0.4 kg of N-alkyl amino acid catalyst. The reaction is carried out for 3 hours at a pressure of 0.2 MPa (gauge pressure) and a temperature of 55°C. The reacted material flows upward in the hydration reactor and flows from the top into a rotating disc extraction column (5 plates, extraction temperature of 30°C, with the hydration reaction liquid and extractant methyl tert-butyl ether extracted countercurrently at a mass ratio of 1:2) for extraction and separation. The separated aqueous phase containing 3-hydroxypropane flows from the bottom of the column into a hydrogenation reactor for hydrogenation. The hydrogenation reaction is carried out at a pressure of 5 MPa (gauge pressure), a temperature of 90°C, and a space velocity of 1.5 h⁻¹. -1 After 1 hour of reaction, the conversion rate of 3-hydroxypropanal was 99.4%, and the selectivity of 1,3-propanediol was 99.5%. In this example, the mass percentage of each component (excluding solvent) in the pre-extraction hydrated reaction solution, the post-extraction oil phase, and the aqueous phase is shown in Table 1. Table 1. Mass percentage of each component before and after extraction. Example 2 The system used in this example is the same as that in Example 1. The specific process for preparing 1,3-propanediol in this example is as follows: 7.8 kg of deionized water was used to prepare 1,3-propanediol. Ionized water was introduced into the first enhanced mass transfer unit of the hydration reactor, along with 0.8 kg of acrolein and 1.4 kg of N-alkyl amino acid catalyst. The reaction was carried out for 2 hours at a pressure of 0.1 MPa (gauge pressure) and a temperature of 35°C. The reacted material flowed upwards in the hydration reactor and flowed from the top into a rotating disc extractor for extraction and separation. The separated aqueous phase containing 3-hydroxypropanal flowed from the bottom into a hydrogenation reactor for hydrogenation. The hydrogenation reaction was carried out at a pressure of 4 MPa (gauge pressure), a temperature of 60°C, and a space velocity of 1.5 h⁻¹. -1 After 1 hour of reaction, the conversion rate of 3-hydroxypropanal was 97.4%, and the selectivity of 1,3-propanediol was 98.5%. Example 3 The system used in this example is the same as that in Example 1. The specific process for preparing 1,3-propanediol in this example is as follows: 9.2 kg of deionized water was used to prepare 1,3-propanediol. Ionized water was introduced into the first enhanced mass transfer unit of the hydration reactor, along with 2.0 kg of acrolein and 1.5 kg of N-alkyl amino acid catalyst. The reaction was carried out for 2 hours at a pressure of 0.4 MPa (gauge pressure) and a temperature of 60°C. The reacted material flowed upwards in the hydration reactor and flowed from the top into a rotating disc extractor for extraction and separation. The separated aqueous phase containing 3-hydroxypropanal flowed from the bottom into a hydrogenation reactor for hydrogenation. The hydrogenation reaction was carried out at a pressure of 4 MPa (gauge pressure), a temperature of 80°C, and a space velocity of 1.5 h⁻¹. -1 After 1 hour of reaction, the conversion rate of 3-hydroxypropanal was 99.8%, and the selectivity of 1,3-propanediol was 99.8%. Example 4 The specific process for preparing 1,3-propanediol in this example is the same as in Example 1, the only difference being that the third enhanced mass transfer device in this example is vertically aligned with the vertical direction. The third enhanced mass transfer device is positioned directly above the second enhanced mass transfer device, with its lower outlet opposite to the upper outlet of the fourth enhanced mass transfer device. In this embodiment, after 1 hour of reaction, the conversion rate of 3-hydroxypropanal is 98.1%, and the selectivity of 1,3-propanediol is 98.3%. Example 5 The specific process for preparing 1,3-propanediol in this example is the same as in Example 1, the only difference being the outlet of the first circulation pipeline and the second... The outlets of the circulation pipelines are at the same height. In this example, after 1 hour of reaction, the conversion rate of 3-hydroxypropanal was 99.1%, and the selectivity of 1,3-propanediol was 99.2%. Comparative Example 1 The specific process for preparing 1,3-propanediol in this example is the same as in Example 1, the only difference being that no reactor is installed in the hydration reactor in this example. The first enhanced mass transfer unit is used; a second enhanced mass transfer unit is not installed in the hydrogenation reactor. After 1 hour of hydrogenation, the conversion rate of 3-hydroxypropanal is 76.3%, and the selectivity of 1,3-propanediol is 87.4%. Comparative Example 2 In this example, the hydration reactor does not have a first enhanced mass transfer unit, and the hydrogenation reactor does not have a second enhanced mass transfer unit. The specific process for preparing 1,3-propanediol in the example is as follows: 6.8 kg of deionized water is introduced into the hydration reactor, along with 1.5 kg of acrolein and 0.4 kg of N-alkyl amino acid catalyst. The reaction is carried out for 3 hours at a pressure of 0.2 MPa (gauge pressure) and a temperature of 55°C. The reacted material flows upward in the hydration reactor and flows from the top into the extraction tower for extraction and separation. The separated aqueous phase containing 3-hydroxypropane flows from the bottom into the hydrogenation reactor for hydrogenation. The hydrogenation reaction is carried out at a pressure of 10 MPa (gauge pressure), a temperature of 110°C, and a space velocity of 1.5 h⁻¹. -1 After 1 hour of reaction, the conversion rate of 3-hydroxypropanal was 84.2%, and the selectivity of 1,3-propanediol was 89.1%. As can be seen from Examples 1-5, the system of the present invention has a high raw material conversion rate in the preparation of 1,3-propanediol, and the selectivity of 1,3-propanediol is good. Comparing Examples 1 and 4, it can be seen that Example 1 is superior to Example 4 in both feed conversion rate and 1,3-propanediol selectivity. This may be because the outlets of the two enhanced mass transfer devices in Example 4 are opposite each other, creating a dead zone in the reaction liquid. Example 1, on the other hand, achieves agitation of the reaction liquid by staggering the outlets of the two enhanced mass transfer devices. Therefore, the catalyst and microbubble distribution in the reaction liquid in the hydrogenation reactor of Example 1 is more uniform, the reaction rate is faster, and both the feed conversion rate and 1,3-propanediol selectivity are better. Comparing Examples 1 and 5, it can be seen that Example 1 is superior to Example 5 in both feed conversion rate and 1,3-propanediol selectivity. This may be because Example 1, by specifically adjusting the outlet positions of the two circulation pipelines, enhanced the agitation effect on the reaction liquid, resulting in better uniformity of catalyst and microbubble distribution in the hydrogenation reactor compared to Example 5, and a faster reaction rate. Consequently, Example 1 exhibits better feed conversion rate and 1,3-propanediol selectivity in the hydrogenation reaction. Comparing Example 1, Comparative Example 2, and Comparative Example 1, it can be seen that the feed conversion rate and the selectivity of 1,3-propanediol in Example 1 are both superior to those in Comparative Examples 1 and 2. This indicates that the present invention, by setting up an enhanced mass transfer unit, increases the phase boundary mass transfer area between feedstocks, increases the reaction rate, and thus improves the feed conversion rate and the selectivity of 1,3-propanediol. In summary, the system of the present invention can increase the phase boundary mass transfer area between the raw materials in the acrolein hydration reaction and the hydrogenation reaction by utilizing a first enhanced mass transfer unit installed in the hydration reactor and a second enhanced mass transfer unit installed in the hydrogenation reactor, thereby improving the raw material conversion rate and the selectivity of 1,3-propanediol. Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.
Claims
1. A system for preparing 1,3-propanediol, characterized in that, include: First feed line, second feed line, third feed line, fourth feed line, hydration reactor, rotary extractor and hydrogenation reactor; The first feed line is used to transport a mixed solution of acrolein, homogeneous catalyst and polymerization inhibitor, and the first feed line is connected to the hydration reactor; The second feed line is used to transport deionized water. The hydration reactor is equipped with a first enhanced mass transfer unit, and the second feed line is connected to the first enhanced mass transfer unit. The outlet of the hydration reactor is connected to the rotary disc extractor, and the aqueous phase outlet of the rotary disc extractor is connected to the bottom of the hydrogenation reactor via a delivery pipeline. The third feed line is used to transport hydrogen, and the hydrogenation reactor is equipped with a second enhanced mass transfer unit. The third feed line is connected to the second enhanced mass transfer unit. The fourth feed line is used to transport the hydrogenation reaction catalyst, and the fourth feed line is connected to the transport line; The hydrogenation reactor is a slurry bed reactor; the material outlet of the hydrogenation reactor is vertically higher than the second enhanced mass transfer unit, and the material outlet is vertically lower than the liquid level inside the hydrogenation reactor; A baffle is provided inside the hydrogenation reactor near the material outlet. The top of the baffle is higher than the material outlet in the vertical direction and lower than the liquid level in the hydrogenation reactor. The bottom of the baffle extends downward at an angle near the side wall of the hydrogenation reactor to form an extension. There is a gap between the bottom of the extension and the side wall of the hydrogenation reactor.
2. The system according to claim 1, characterized in that, The first enhanced mass transfer unit includes a first enhanced mass transfer device and a second enhanced mass transfer device, and the second feed pipeline is connected to the first enhanced mass transfer device and the second enhanced mass transfer device respectively. Both the first and second enhanced mass transfer devices have outlets at their upper and lower ends. The number of outlets at the upper end of the first enhanced mass transfer device is less than the number of outlets at the lower end, while the number of outlets at the upper end of the second enhanced mass transfer device is greater than the number of outlets at the lower end. The first enhanced mass transfer device is arranged vertically above the second enhanced mass transfer device, and the first enhanced mass transfer device and the second enhanced mass transfer device are staggered in the vertical direction.
3. The system according to claim 2, characterized in that, The first feed line has a first outlet and a second outlet. The first outlet is located above the second outlet in the vertical direction, and both the first outlet and the second outlet are located between the first enhanced mass transfer device and the second enhanced mass transfer device in the vertical direction. The first outlet is connected to the side wall of the hydration reactor that is farther away from the first enhanced mass transfer device, and the second outlet is connected to the side wall of the hydration reactor that is farther away from the second enhanced mass transfer device.
4. The system according to claim 1, characterized in that, The second enhanced mass transfer unit includes a third enhanced mass transfer device and a fourth enhanced mass transfer device, and the third feed pipeline is connected to the third enhanced mass transfer device and the fourth enhanced mass transfer device respectively; Both the third and fourth enhanced mass transfer devices are provided with outlets at their upper and lower ends. The number of outlets at the upper end of the third enhanced mass transfer device is less than the number of outlets at the lower end, and the number of outlets at the upper end of the fourth enhanced mass transfer device is greater than the number of outlets at the lower end. The third enhanced mass transfer device is arranged vertically above the fourth enhanced mass transfer device, and the third enhanced mass transfer device and the fourth enhanced mass transfer device are staggered in the vertical direction.
5. The system according to claim 4, characterized in that, It also includes a first circulation pipeline, the inlet of which is connected to the bottom of the hydrogenation reactor, and the outlet of which is connected to the side wall of the hydrogenation reactor that is farther away from the fourth enhanced mass transfer device; the outlet of the first circulation pipeline is located between the third enhanced mass transfer device and the fourth enhanced mass transfer device.
6. The system according to claim 5, characterized in that, It also includes a second circulation pipeline; the inlet of the second circulation pipeline is connected to the side wall of the hydrogenation reactor near the baffle and the inlet of the second circulation pipeline is lower than the bottom of the extension in the vertical direction; the outlet of the second circulation pipeline is connected to the side wall of the hydrogenation reactor that is farther away from the third enhanced mass transfer device; the outlet of the second circulation pipeline is located between the third enhanced mass transfer device and the fourth enhanced mass transfer device; Preferably, the outlet of the first circulation pipe is located vertically below the outlet of the second circulation pipe.
7. The system according to any one of claims 1-6, characterized in that, The hydrogenation reactor is provided with multiple baffles, which are staggered and located vertically between the baffles and the second enhanced mass transfer unit. Preferably, the partition is inclined downward along the direction away from the side wall of the hydrogenation reactor.
8. The system according to any one of claims 1-6, characterized in that, It also includes a settling tank and a filter; the material outlet is connected to the settling tank, and the settling tank is connected to the filter; the filter is provided with an arc-shaped filter cloth; the arc-shaped filter cloth divides the internal chamber of the filter into a filtration chamber and a filtrate chamber, the filtrate chamber is connected to the product pipeline, and the side wall of the filtration chamber is connected to the hydrogenation reactor; Preferably, the number of filters is two, and the two filters are arranged in parallel; Preferably, a guide plate is provided at the inlet of the filter, and the guide plate extends downward at an angle close to the arc-shaped filter cloth.
9. The system according to any one of claims 1-6, characterized in that, The oil phase outlet of the rotary extraction tower is connected to the distillation tower; the bottom and top outlets of the distillation tower are both connected to the first feed pipeline, and the middle section outlet of the distillation tower is connected to the rotary extraction tower.
10. A method for preparing 1,3-propanediol, characterized in that, 1,3-propanediol is prepared using the system according to any one of claims 1-9.