System for preparing 1, 3-propylene glycol

Abstract

The utility model provides a system for preparing 1, 3-propylene glycol. The system comprises a first feeding pipeline, a second feeding pipeline, a third feeding pipeline, a fourth feeding pipeline, a hydration reactor, a turntable extraction tower and a hydrogenation reactor, the first feeding pipeline is connected with the hydration reactor; a first enhanced mass transfer unit is arranged in the hydration reactor, and the second feeding pipeline is connected with the first enhanced mass transfer unit; an outlet of the hydration reactor is connected with the turntable extraction tower; a water phase outlet of the turntable extraction tower is connected with the bottom of the hydrogenation reactor through a conveying pipeline; a second enhanced mass transfer unit is arranged in the hydrogenation reactor, and the third feeding pipeline is connected with the second enhanced mass transfer unit; the fourth feeding pipeline is connected with the conveying pipeline; the hydrogenation reactor is a slurry bed reactor; a material outlet of the hydrogenation reactor is higher than the second enhanced mass transfer unit in the vertical direction, and the material outlet is lower than the liquid level in the hydrogenation reactor in the vertical direction. The system can be used for adding a catalyst required by hydrogenation reaction in real time.

Description

TECHNICAL FIELD

[0001] The utility model relates to 1,3 -propylene glycol preparation technical field, specifically, relate to a kind of for preparing 1,3 -propylene glycol system. BACKGROUND

[0002] 1,3 -propylene glycol is an important chemical raw material, is the key raw material of synthesis polytrimethylene terephthalate (PTT), PTT is a high-performance polyester fiber, widely used in textile and clothing industry, commonly used as polyester polyol raw material, polyether polyol initiator and polyurethane chain extender, for producing high-performance polyurethane material.1,3 -propylene glycol can be used as humectant, solvent and emulsifier in food industry, can prolong the shelf life of food and maintain taste and moisture.Used as organic solvent in lubricant, antifreeze and other industries.

[0003] In related art, 1,3 -propylene glycol preparation process is mostly prepared by propylene aldehyde hydration hydrogenation, and the current hydrogenation reaction process mostly uses fixed bed reactor, which needs to be parked regularly to replace catalyst in production process, has large energy consumption, and brings economic loss and safety risk.

[0004] Therefore, the utility model is proposed. UTILITY MODEL CONTENT

[0005] The first purpose of the utility model is to provide a system for preparing 1,3 -propylene glycol, which adopts slurry bed for hydrogenation reaction, and can add catalyst required for hydrogenation reaction in real time through the fourth feed pipe in the production process, thereby solving the problem of replacing catalyst in fixed bed; and the first reinforced mass transfer unit arranged in the hydration reactor and the second reinforced mass transfer unit arranged in the hydrogenation reactor can increase the phase boundary mass transfer area between raw materials in propylene aldehyde hydration reaction and hydrogenation reaction, improve the raw material conversion rate, and reduce the energy consumption required for reaction, which helps to increase production income.

[0006] The second purpose of the utility model is to provide a method for preparing 1,3 -propylene glycol, which can realize efficient production of 1,3 -propylene glycol by using the above system.

[0007] In order to achieve the above purposes of the utility model, the following technical solutions are adopted:

[0008] The utility model provides a system for preparing 1,3 -propylene glycol, comprising: first feed pipe, second feed pipe, third feed pipe, fourth feed pipe, hydration reactor, rotary disc extraction tower and hydrogenation reactor.

[0009] The first feeding pipeline is used for conveying a mixed solution of propenal, homogeneous catalyst and polymerization inhibitor, and is connected with the hydration reactor;

[0010] The second feeding pipeline is used for conveying deionized water, and the hydration reactor is provided with a first mass transfer intensifier set, and the second feeding pipeline is connected with the first mass transfer intensifier set;

[0011] The outlet of the hydration reactor is connected with the rotating disc extraction column, and the water phase outlet of the rotating disc extraction column is connected with the bottom of the hydrogenation reactor through a conveying pipeline;

[0012] The third feeding pipeline is used for conveying hydrogen, and the hydrogenation reactor is provided with a second mass transfer intensifier set, and the third feeding pipeline is connected with the second mass transfer intensifier set;

[0013] The fourth feeding pipeline is used for conveying hydrogenation reaction catalyst, and the fourth feeding pipeline is connected with the conveying pipeline;

[0014] The hydrogenation reactor is a slurry bed reactor, the material outlet of the hydrogenation reactor is higher than the second mass transfer intensifier set in the vertical direction, and the material outlet is lower than the liquid level in the hydrogenation reactor in the vertical direction;

[0015] A baffle is arranged in the hydrogenation reactor close to the material outlet, the top of the baffle is higher than the material outlet and lower than the liquid level of the hydrogenation reactor in the vertical direction, the bottom of the baffle extends downward to form an extension part close to the side wall of the hydrogenation reactor, and the bottom of the extension part has a gap with the side wall of the hydrogenation reactor.

[0016] In the above scheme, propenal, homogeneous catalyst and polymerization inhibitor are mixed in the first feed pipeline, wherein the homogeneous catalyst is used to catalyze the hydration reaction, and the polymerization inhibitor is used to avoid the dimerization of propenal and improve the product selectivity. By mixing the homogeneous catalyst and the polymerization inhibitor into the propenal in advance before the reaction, the homogeneous catalyst and the polymerization inhibitor can be uniformly distributed in the hydration reactor, thereby better exerting the catalytic and polymerization inhibition effects and improving the conversion rate of the reaction raw materials while reducing the occurrence of side reactions. By arranging the first mass transfer intensifier unit in the hydration reactor, deionized water can be dispersed into micron-sized microdroplets, thereby increasing the interfacial mass transfer area of deionized water and propenal, which helps to improve the efficiency of the hydration reaction and the conversion rate of the raw materials, and to a certain extent, reduces the requirements for temperature and pressure of the hydration reaction, thereby helping to reduce the energy consumption of the reaction. The hydrogenation reactor of the scheme adopts a slurry bed reactor, and a hydrogenation reaction catalyst is added to the hydrogenation reactor through the fourth feed pipeline, so that the hydrogenation reaction catalyst can be replaced in real time during production, thereby solving the problem of catalyst replacement of the fixed bed. By arranging the second mass transfer intensifier unit in the hydrogenation reactor, hydrogen can be dispersed and broken into micron-sized micro-bubbles, thereby increasing the interfacial mass transfer area of hydrogen and 3-hydroxypropionaldehyde, which helps to improve the reaction efficiency of the hydrogenation reaction, the conversion rate of 3-hydroxypropionaldehyde, and the selectivity of 1,3-propanediol, and to a certain extent, reduces the requirements for temperature and pressure of the hydrogenation reaction, thereby helping to reduce the energy consumption of the reaction. By arranging 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, and 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 to participate in the reaction, thereby improving the purity of the product output by the material outlet and the utilization rate of the catalyst, which helps to save costs.

[0017] Preferably, the first mass transfer intensifier unit comprises a first mass transfer intensifier and a second mass transfer intensifier, and the second feed pipeline is connected to the first mass transfer intensifier and the second mass transfer intensifier, respectively.

[0018] The first mass transfer intensifier and the second mass transfer intensifier are both provided with outlets at the upper and lower ends, the number of upper end outlets of the first mass transfer intensifier is less than that of lower end outlets, and the number of upper end outlets of the second mass transfer intensifier is greater than that of lower end outlets.

[0019] The first mass transfer intensifier is arranged above the second mass transfer intensifier in the vertical direction, and the first mass transfer intensifier and the second mass transfer intensifier are arranged in a staggered manner in the vertical direction.

[0020] In the above scheme, both of the two enhanced mass transfer devices adopt a horn-shaped structure with more outlets at one end and less outlets at the other end, so that the distribution of the output microdroplets is more reasonable, and by arranging the first enhanced mass transfer device and the second enhanced mass transfer device in a staggered manner in the vertical direction, the lower end outlet of the first enhanced mass transfer device and the upper end outlet of the second enhanced mass transfer device can be staggered with each other. This arrangement can avoid the collision of the two microdroplet flows to cause liquid dead zones, and can use the microdroplets sprayed by the two enhanced mass transfer devices to stir the reaction liquid in the hydration reactor. On the one hand, this can make the microdroplets uniformly distributed, further increase the mass transfer area and the contact area between the reaction materials, and improve the reaction efficiency. On the other hand, it can ensure the uniform distribution of the homogeneous catalyst and the polymerization inhibitor in the reaction liquid by stirring the reaction liquid, and ensure the catalytic effect of the homogeneous catalyst and the polymerization inhibition effect of the polymerization inhibitor, which helps to further improve the reaction efficiency of the hydration reaction.

[0021] Preferably, the first feed pipe has a first outlet and a second outlet, the first outlet is located above the second outlet in the vertical direction, and the first outlet and the second outlet are both located between the first enhanced mass transfer device and the second enhanced mass transfer device in the vertical direction.

[0022] The first outlet is connected to a side wall of the hydration reactor that is far away from the first enhanced mass transfer device, and the second outlet is connected to a side wall of the hydration reactor that is far away from the second enhanced mass transfer device.

[0023] In the above scheme, the two outlets of the first feed pipe are located between the two enhanced mass transfer devices. It can be understood that there are more microdroplets between the two enhanced mass transfer devices. This way of directly supplementing propenal between the two enhanced mass transfer devices can ensure that the reaction proceeds stably. In addition, by connecting the first outlet to a side wall of the hydration reactor that is far away from the first enhanced mass transfer device and connecting the second outlet to a side wall of the hydration reactor that is far away from the second enhanced mass transfer device, the power of the materials output by the two outlets and the power of the microdroplets output by the two enhanced mass transfer devices can be used to stir the reaction liquid between the two enhanced mass transfer devices. This can make the microdroplets, homogeneous catalysts, and polymerization inhibitors uniformly distributed, thereby helping to improve the hydration reaction efficiency.

[0024] 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 pipe is connected to the third enhanced mass transfer device and the fourth enhanced mass transfer device, respectively.

[0025] The third enhanced mass transfer device and the fourth enhanced mass transfer device are both provided with outlets at the upper and lower ends, the number of upper end outlets of the third enhanced mass transfer device is less than the number of lower end outlets, and the number of upper end outlets of the fourth enhanced mass transfer device is greater than the number of lower end outlets.

[0026] The third intensified mass transfer device is arranged above the fourth intensified mass transfer device in the vertical direction, and the third intensified mass transfer device and the fourth intensified mass transfer device are staggered in the vertical direction.

[0027] In the above scheme, both of the intensified mass transfer devices adopt the horn-shaped structure with more outlets at one end and less outlets at the other end, so that the output micro-bubbles can be more reasonably distributed in the hydrogenation reactor, and by staggering the third intensified mass transfer device and the fourth intensified mass transfer device in the vertical direction, the lower end outlet of the third intensified mass transfer device and the upper end outlet of the fourth intensified mass transfer device are staggered with each other, which can avoid the collision of the two micro-bubble flows to cause liquid dead zones, and the micro-bubbles sprayed by the two intensified mass transfer devices can be used to stir the reaction liquid in the hydrogenation reactor, which can on the one hand make the micro-bubbles uniformly distributed, further increase the mass transfer area and the contact area between the reaction materials, and improve the reaction efficiency, and on the other hand, by stirring the reaction liquid, the hydrogenation reaction catalyst in the reaction liquid can be uniformly distributed, so as to ensure the catalytic effect of the catalyst, which is helpful to further improve the reaction efficiency of the hydrogenation reaction.

[0028] Preferably, the system further comprises a first circulation pipeline, an inlet of the first circulation pipeline is connected to the bottom of the hydrogenation reactor, and an outlet of the first circulation pipeline is connected to the side wall of the hydrogenation reactor far from the fourth intensified mass transfer device; the outlet of the first circulation pipeline is located between the third intensified mass transfer device and the fourth intensified mass transfer device.

[0029] In the above scheme, the first circulation pipeline can circulate the reaction liquid at the bottom of the hydrogenation reactor to the space between the two intensified mass transfer devices, which can stir the bottom of the hydrogenation reactor and avoid the catalyst from depositing at the bottom.

[0030] Preferably, the system further comprises a second circulation pipeline; an inlet of the second circulation pipeline is connected to the side wall of the hydrogenation reactor close to the baffle, and the inlet of the second circulation pipeline is lower than the bottom of the extension part in the vertical direction; an outlet of the second circulation pipeline is connected to the side wall of the hydrogenation reactor far from the third intensified mass transfer device; and the outlet of the second circulation pipeline is located between the third intensified mass transfer device and the fourth intensified mass transfer device.

[0031] In the above scheme, the second circulation pipeline can directly input the lower turbid liquid containing a higher concentration of catalyst obtained by the internal settling tank to the space between the two intensified mass transfer devices, and realize uniform dispersion by the stirring of the micro-bubble flow of the two intensified mass transfer devices, which is helpful to further improve the utilization rate and catalytic effect of the catalyst.

[0032] Preferably, the outlet of the first circulation pipeline is located below the outlet of the second circulation pipeline in the vertical direction. This arrangement can make the two liquid streams output by the two circulation pipelines and the micro-bubble streams output by the two intensifiers to stir the reaction liquid together, thereby improving the stirring effect on the reaction liquid and improving the uniformity of the distribution of the micro-bubbles and the catalyst in the reaction liquid.

[0033] Preferably, a plurality of baffles are arranged in the hydrogenation reactor, the plurality of baffles are staggered, and the plurality of baffles are located between the baffle and the second intensifier in the vertical direction. Preferably, the baffles are arranged to be inclined downward away from the side wall of the hydrogenation reactor. This scheme can reduce the flow speed of the upper reaction liquid and promote the settlement of the catalyst in the reaction liquid, thereby reducing the purity of the product output by the material outlet. In a further scheme, by arranging the baffles to be inclined downward, the settled catalyst can flow back into the reaction liquid below the baffles, avoiding the accumulation of the settled catalyst.

[0034] Preferably, the system further comprises a settling tank and a filter; the material outlet is connected to the settling tank, the settling tank is connected to the filter; an arc-shaped filter cloth is arranged in the filter; the arc-shaped filter cloth divides the internal chamber of the filter into a filtering cavity and a filtrate cavity, the filtrate cavity is connected to a product pipeline, and the side wall of the filtering cavity 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 arranged at the inlet of the filter, and the guide plate is arranged to extend downward and incline toward the arc-shaped filter cloth. In this scheme, the filter cloth of the filter adopts a 1 / 4 circular arc design, which is more conducive to the recovery of the catalyst and can effectively prevent the catalyst from blocking the filter cloth; in a further scheme, the number of filters is two, and the two filters can adopt an open-close application mode to avoid stopping for cleaning the filter, which helps to increase the production efficiency; in a further scheme, a guide plate is arranged in the filter, which can play a guiding and buffering role and can avoid the coarse product entering the filter from directly impacting the arc-shaped filter cloth, thereby ensuring the filtering effect of the arc-shaped filter cloth.

[0035] Preferably, the oil phase outlet of the rotating disc extraction column is connected to the rectification column; the bottom outlet and the top outlet of the rectification column are both connected to the first feed pipeline, and the middle outlet of the rectification column is connected to the rotating disc extraction column. In this scheme, the water phase containing 3-hydroxypropanal separated by the rotating disc extraction column flows from the bottom into the hydrogenation reactor for hydrogenation reaction, and the oil phase containing the homogeneous catalyst and unreacted propenal flows from the top into the rectification column for rectification separation. The propenal produced at the top of the rectification column flows into the hydration reactor for recycling, the extractant produced at the middle of the rectification column flows into the extraction column for recycling, and the homogeneous catalyst produced at the bottom of the rectification column flows into the hydration reactor for recycling. The recycling of the materials can significantly improve the product yield, and the recovery of the raw materials has no adverse effect on the reaction process.

[0036] It can be understood by those skilled in the art that the enhanced mass transfer device adopted in the present application has been embodied in the prior patents of the present inventor, such as the patents with application numbers CN201610641119.6, CN201610641251.7, CN201710766435.0, publication numbers CN106187660A, CN105903425A, CN205833127U and CN207581700U. The specific product structure and working principle of the micron bubble generator (i.e. bubble breaker) are introduced in detail in the prior patent CN201610641119.6. It is recorded in the application file that "the micron bubble generator comprises a body and a secondary breaking piece, the body has a cavity, the body is provided with an inlet communicating with the cavity, the opposite first end and the second end of the cavity are both open, wherein the cross-sectional area of the cavity decreases from the middle of the cavity to the first end and the second end of the cavity; the secondary breaking piece is arranged at least one of the first end and the second end of the cavity, a part of the secondary breaking piece is arranged in the cavity, and an annular channel is formed between the secondary breaking piece and the open hole at both ends of the cavity. The micron bubble generator further comprises a gas inlet pipe and a liquid inlet pipe." From the specific structure disclosed in the application file, it can be known that the specific working principle is that the liquid enters the micron bubble generator tangentially through the liquid inlet pipe, rotates at a high speed and cuts the gas, so that the gas bubbles are broken into micron-sized micro-bubbles, thereby increasing the mass transfer area between the liquid phase and the gas phase, and the micron bubble generator in the patent belongs to a pneumatic bubble breaker.

[0037] In addition, the prior patent 201610641251.7 discloses that a primary bubble breaker has a circulating liquid inlet, a circulating gas inlet and a gas-liquid mixture outlet, and a secondary bubble breaker is communicated with the feed inlet and the gas-liquid mixture outlet, which indicates that the bubble breaker needs to be mixed with gas and liquid. In addition, from the following drawings, it can be known that the primary bubble breaker mainly uses the circulating liquid as power, so the primary bubble breaker actually belongs to a liquid-driven type of enhanced reactor, and the secondary bubble breaker is communicated with the gas-liquid mixture into the rotating ball in the elliptical shape to rotate, so that the bubble breaking is realized in the rotating process, and the secondary bubble breaker actually belongs to a gas-liquid linkage type of bubble breaker. Actually, whether the liquid-driven type of bubble breaker or the gas-liquid linkage type of bubble breaker belongs to a specific form of the bubble breaker, however, the enhanced mass transfer device adopted in the utility model is not limited to the above-mentioned several forms, and the specific structure of the bubble breaker disclosed in the prior patent is only one of the forms that can be adopted in the utility model.

[0038] In addition, the prior patent 201710766435.0 discloses that the principle of the bubble breaker is to achieve mutual collision of gas by high-speed jet flow. Moreover, the prior patent CN106187660 also discloses the specific structure of the bubble breaker, and the specific working principle of the bubble breaker S-2 is described in detail in the

[0031] -

[0041] section of the specification and the drawing part. The liquid phase inlet is arranged at the top of the bubble breaker, and the gas phase inlet is arranged at the side. The liquid phase that enters from the top provides the entrainment power, so that the effect of being broken into superfine bubbles is achieved. It can be seen from the drawing that the bubble breaker has a conical structure, and the diameter of the upper part is larger than that of the lower part, so that the liquid phase can better provide the entrainment power.

[0039] In the early stage of the prior patent application, the bubble breaker is just developed, so it is named as a micron bubble generator (CN201610641119.6) in the early stage. With continuous technical improvement, it is renamed as a bubble breaker in the later stage. The enhanced mass transfer device in the utility model is equivalent to the micron bubble generator and the micro-interface generator in the prior art, and only the name is different. In summary, the enhanced mass transfer device in the utility model belongs to the prior art.

[0040] The utility model also provides a method for preparing 1,3-propanediol, which uses the system of any one of the above-mentioned embodiments to prepare 1,3-propanediol.

[0041] Compared with the prior art, the utility model has the beneficial effects that:

[0042] 1、In the first feed pipeline mixed with propenal, homogeneous catalyst and polymerization inhibitor, wherein the homogeneous catalyst is used to catalyze the hydration reaction to occur, and the polymerization inhibitor is used to avoid the dimerization reaction of propenal, thereby improving the product selectivity, and the scheme is to mix the homogeneous catalyst and the polymerization inhibitor into the propenal in advance before the reaction, which helps to uniformly distribute the homogeneous catalyst and the polymerization inhibitor in the hydration reactor, thereby helping to better play the catalytic and polymerization inhibition effects and improve the conversion rate of the reaction raw materials, while reducing the occurrence of side reactions;

[0043] 2、By setting the first mass transfer intensifier unit in the hydration reactor, the deionized water can be dispersed into micron-sized microdroplets, thereby increasing the phase boundary mass transfer area of the deionized water and propenal, which helps to improve the efficiency of the hydration reaction and the conversion rate of the raw materials, and to a certain extent, reduces the requirements of the hydration reaction on temperature and pressure, thereby helping to reduce the reaction energy consumption;

[0044] 3、The hydrogenation reactor of the scheme adopts a slurry bed reactor, and a hydrogenation reaction catalyst is added to the hydrogenation reactor through the fourth feed pipeline, so that the hydrogenation reaction catalyst can be replaced in real time during production, thereby solving the problem of catalyst replacement of the fixed bed;

[0045] 4、By setting the second mass transfer intensifier unit in the hydrogenation reactor, hydrogen can be dispersed and broken into micron-sized micro-bubbles, thereby increasing the phase boundary mass transfer area of hydrogen and 3-hydroxypropanal, which helps to improve the reaction efficiency of the hydrogenation reaction, the conversion rate of 3-hydroxypropanal, and the selectivity of 1,3-propanediol, and to a certain extent, reduces the requirements of the hydrogenation reaction on temperature and pressure, thereby helping to reduce the reaction energy consumption;

[0046] 5、By setting a baffle in the hydrogenation reactor close to the material outlet, 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, and 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 to participate in the reaction, thereby improving the purity of the product output by the material outlet and the utilization rate of the catalyst, which helps to save costs. BRIEF DESCRIPTION OF DRAWINGS

[0047] Various other advantages and benefits will become apparent to those of ordinary skill in the art upon reading the following detailed description of the preferred embodiments. The drawings are for purposes of illustration only and are not considered a limitation of the present application. Moreover, like reference numerals are used to designate identical parts throughout the specification and drawings. In the drawings:

[0048] Figure 1 A structure schematic diagram of a system for preparing 1,3-propanediol according to Embodiment 1 of the present application is shown.

[0049] Figure 2 Fig. 1 shows a schematic diagram of the liquid flow direction between the first and second enhanced mass transfer devices in the hydration reactor of the embodiment 1 of the present application;

[0050] Figure 3 Fig. 2 shows a schematic diagram of the structure of the hydrogenation reactor of the embodiment 1 of the present application;

[0051] Figure 4 Fig. 3 shows a schematic diagram of the liquid flow direction between the third and fourth enhanced mass transfer devices in the hydrogenation reactor of the embodiment 1 of the present application;

[0052] Figure 5 Fig. 4 shows a schematic diagram of the structure of the filter of the embodiment 1 of the present application.

[0053] In the figure: 1, hydration reactor; 2, first enhanced mass transfer device; 3, first feeding pipeline; 4, second feeding pipeline; 5, second enhanced mass transfer device; 6, rotary disc extraction tower; 7, rectifying tower; 8, hydrogenation reactor; 9, fourth feeding pipeline; 10, settling tank; 11, filter; 12, third feeding pipeline; 13, first circulating pipeline; 14, second circulating pipeline; 15, partition plate; 16, extension; 17, baffle; 18, fourth enhanced mass transfer device; 19, third enhanced mass transfer device; 20, arc-shaped filter cloth; 21, guide plate; 22, conveying pipeline. DETAILED DESCRIPTION

[0054] The technical solutions of the present application will be described clearly and completely in combination with the drawings and specific embodiments, but those skilled in the art will understand that the following described embodiments are part of the embodiments of the present application, rather than all the embodiments, and are only used to illustrate the present application, and should not be regarded as limiting the scope of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application. The specific conditions are not specified in the embodiments, and are carried out according to the conventional conditions or the conditions recommended by the manufacturer. The reagents or instruments used are not specified by the manufacturer, and are all conventional products that can be purchased on the market.

[0055] In the description of the utility model, it is necessary to explain, the term "center", "upper", "lower", "left", "right", "vertical", "horizontal", "internal", "external" and so on indicate the orientation or positional relationship is based on the orientation or positional relationship shown in the drawing, only for the convenience of describing the utility model and simplifying the description, and is not indicating or implying that the device or element indicated must have a particular orientation, a particular orientation and operation, therefore, it cannot be understood as a limitation on the utility model. In addition, the terms "first", "second", "third" are only for the purpose of description, and cannot be understood as indicating or implying relative importance.

[0056] In the description of the utility model, it is necessary to explain, unless otherwise expressly provided and limited, the terms "mounting", "connecting", "connecting" should be understood broadly, for example, it can be fixedly connected, can also be detachably connected, or integrally connected, can be mechanically connected, can also be electrically connected, can be directly connected, can also be indirectly connected through an intermediate medium, can be the communication inside two elements. For ordinary skilled in the art, the specific meaning of the above terms in the utility model can be understood according to the specific circumstances.

[0057] In order to more clearly set forth the technical scheme in the utility model, the following is explained in the form of specific embodiments.

[0058] Embodiment 1

[0059] Combined with reference Figures 1-5The embodiment provides a system for preparing 1,3-propanediol, which comprises a first feeding pipeline 3, a second feeding pipeline 4, a third feeding pipeline 12, a fourth feeding pipeline 9, a hydration reactor 1, a rotating disc extractor 6 and a hydrogenation reactor 8; the first feeding pipeline 3 is used for conveying a mixed solution of acrolein, a homogeneous catalyst and a polymerization inhibitor, and is connected with the hydration reactor 1; the second feeding pipeline 4 is used for conveying deionized water, and a first enhanced mass transfer unit is arranged in the hydration reactor 1 and connected with the second feeding pipeline 4; the outlet of the hydration reactor 1 is connected with the rotating disc extractor 6, and the water phase outlet of the rotating disc extractor 6 is connected with the bottom of the hydrogenation reactor 8 through a conveying pipeline 22; the third feeding pipeline 12 is used for conveying hydrogen, and a second enhanced mass transfer unit is arranged in the hydrogenation reactor 8 and connected with the third feeding pipeline 12; the fourth feeding pipeline 9 is used for conveying a hydrogenation reaction catalyst, and is connected with the conveying pipeline 22; the hydrogenation reactor 8 is a slurry bed reactor; the material outlet of the hydrogenation reactor 8 is higher than the second enhanced mass transfer unit in the vertical direction, and is lower than the liquid level in the hydrogenation reactor 8 in the vertical direction; a baffle 17 is arranged in the hydrogenation reactor 8 close to the material outlet, the top of the baffle 17 is higher than the material outlet and lower than the liquid level of the hydrogenation reactor 8 in the vertical direction; the bottom of the baffle 17 extends downward along the direction close to the side wall of the hydrogenation reactor 8 to form an extension 16, and the bottom of the extension 16 has a gap with the side wall of the hydrogenation reactor 8.

[0060] The homogeneous catalyst, the polymerization inhibitor and the hydrogenation reaction catalyst can be selected according to requirements. In the embodiment, the homogeneous catalyst can be N-alkyl amino acid, and the addition amount of the homogeneous catalyst can be 5-15% of the mass of the hydration reaction liquid. The pressure of the hydration reaction can be 0-0.5 MPa (gauge pressure), the temperature can be 30-60 DEG C, and the time can be 2-4 h. The addition amount of acrolein in the hydration reaction can be 5-25% of the mass of the hydration reaction liquid. The pressure of the hydrogenation reaction can be 2-5 MPa (gauge pressure), the temperature can be 40-100 DEG C, the space velocity can be 1-5 h -1 .

[0061] The polymerization inhibitor can be hydroquinone, and the addition amount of the hydroquinone can be 0-0.1% of the mass of the hydration reaction liquid. In the hydration reaction, acrolein is prone to dimerization, which reduces the selectivity, and the dimer has a certain interaction relationship with the product, which is difficult to separate and affects the quality of the product. A small amount of polymerization inhibitor enters the oil phase in the subsequent extraction operation process, enters the tower kettle N-alkyl amino acid stream in the process of oil phase separation, and is recovered into the hydration reactor 1 together with the stream, and the remaining polymerization inhibitor enters the hydrogenation reactor 8 with the water phase, but the presence of the polymerization inhibitor has no adverse effect on the hydrogenation reaction.

[0062] The hydrogenation catalyst can be a powder supported noble metal catalyst, the noble metal is selected from nickel, palladium, rhodium or platinum, the support is alumina, titania or silica, and the content of noble metal in the supported noble metal catalyst is 5-30wt%.

[0063] In this embodiment, the propenal, the homogeneous catalyst and the polymerization inhibitor can be mixed in advance and then input into the hydration reactor 1 through the first feeding pipeline 3. It can be understood that water pumps can be arranged on the pipelines to ensure the flow of materials in the pipelines, which will not be described here.

[0064] In this embodiment, the baffle 17 and the side wall of the hydration reactor 1 can form an internal settling tank, the volume of the tank can be 1 / 20-1 / 10 of the volume of the hydrogenation reactor 8, the height can be 1 / 5-3 / 5 of the height of the hydrogenation reactor 8, and the width can be 1 / 10-1 / 5 of the hydrogenation reactor 8, wherein the height of the lower slurry is 1 / 10-1 / 5 of the height of the tank. The internal settling tank can make part of the powder catalyst settle in the tank, reduce the amount of catalyst recovered subsequently, and save costs.

[0065] In this embodiment, the theoretical plate number of the rotating disc extraction column 6 is 3-6, 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℃.

[0066] In this embodiment, as shown in Figure 1 The oil phase outlet of the rotating disc extraction column 6 is connected to the rectifying column 7; the bottom outlet and the top outlet of the rectifying column 7 are both connected to the first feeding pipeline 3, and the middle outlet of the rectifying column 7 is connected to the rotating disc extraction column 6. The water phase separated from the rotating disc extraction column 6 and containing 3-hydroxypropionaldehyde flows into the hydrogenation reactor 8 for hydrogenation reaction, and the oil phase containing N-alkyl amino acid and unreacted propenal flows into the rectifying column 7 for rectification and separation. The propenal produced at the top of the rectifying column 7 flows into the hydration reactor 1 for recycling, the extractant produced in the middle of the rectifying column 7 flows into the extraction column for recycling, and the N-alkyl amino acid produced at the bottom of the rectifying column 7 flows 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 effect on the reaction process.

[0067] Continuing to refer to Figure 1In the embodiment, the first enhanced mass transfer unit comprises a first enhanced mass transfer device 2 and a second enhanced mass transfer device 5, and the second feed pipe 4 is connected to the first enhanced mass transfer device 2 and the second enhanced mass transfer device 5 respectively; the first enhanced mass transfer device 2 and the second enhanced mass transfer device 5 are both provided with outlets at the upper and lower ends, the number of the upper end outlets of the first enhanced mass transfer device 2 is less than that of the lower end outlets, and the number of the upper end outlets of the second enhanced mass transfer device 5 is greater than that of the lower end outlets; the first enhanced mass transfer device 2 is arranged above the second enhanced mass transfer device 5 in the vertical direction, and the first enhanced mass transfer device 2 and the second enhanced mass transfer device 5 are staggered in the vertical direction. In the embodiment, the enhanced mass transfer devices (including the first enhanced mass transfer device 2, the second enhanced mass transfer device 5, the third enhanced mass transfer device 19 and the fourth enhanced mass transfer device 18) are all horn-shaped, and the length ratio of the two ends is 5:2.

[0068] With reference to Figure 1 In the embodiment, the first feed pipe 3 is provided with a first outlet and a second outlet, the first outlet is located above the second outlet in the vertical direction, and the first outlet and the second outlet are both located between the first enhanced mass transfer device 2 and the second enhanced mass transfer device 5 in the vertical direction; the first outlet is connected to the side wall of the hydration reactor 1 far from the first enhanced mass transfer device 2, and the second outlet is connected to the side wall of the hydration reactor 1 far from the second enhanced mass transfer device 5. In this case, as Figure 2 shown. The reaction liquid between the two enhanced mass transfer devices can be stirred in the clockwise direction under the power of the two outlet materials and the power of the two enhanced mass transfer devices outputting microdroplets, thereby improving the uniformity of the distribution of the catalyst and the microdroplets in the reaction liquid.

[0069] With reference to Figure 1 , the second enhanced mass transfer unit comprises a third enhanced mass transfer device 19 and a fourth enhanced mass transfer device 18, and the third feed pipe 12 is connected to the third enhanced mass transfer device 19 and the fourth enhanced mass transfer device 18 respectively; the third enhanced mass transfer device 19 and the fourth enhanced mass transfer device 18 are both provided with outlets at the upper and lower ends, the number of the upper end outlets of the third enhanced mass transfer device 19 is less than that of the lower end outlets, and the number of the upper end outlets of the fourth enhanced mass transfer device 18 is greater than that of the lower end outlets; the third enhanced mass transfer device 19 is arranged above the fourth enhanced mass transfer device 18 in the vertical direction, and the third enhanced mass transfer device 19 and the fourth enhanced mass transfer device 18 are staggered in the vertical direction.

[0070] With reference to Figure 1 , Figure 3, the system further comprises 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 far from the fourth intensified mass transfer device 18; the outlet of the first circulation pipeline 13 is located between the third intensified mass transfer device 19 and the fourth intensified mass transfer device 18. The reaction liquid at the bottom of the hydrogenation reactor 8 is pumped into the space between the third intensified mass transfer device 19 and the fourth intensified mass transfer device 18 through the first circulation pipeline 13.

[0071] With reference to Figure 1 , Figure 3 , the system further comprises a second circulation pipeline 14; the inlet of the second circulation pipeline 14 is connected to the side wall of the hydrogenation reactor 8 close to the baffle 17, and the inlet of the second circulation pipeline 14 is lower than the bottom of the extension 16 in the vertical direction; the outlet of the second circulation pipeline 14 is connected to the side wall of the hydrogenation reactor 8 far from the third intensified mass transfer device 19; the outlet of the second circulation pipeline 14 is located between the third intensified mass transfer device 19 and the fourth intensified mass transfer device 18. The lower slurry settled in the settling tank is pumped into the space between the third intensified mass transfer device 19 and the fourth intensified mass transfer device 18 through the second circulation pipeline 14.

[0072] In the embodiment, the outlet of the first circulation pipeline 13 is located below the outlet of the second circulation pipeline 14 in the vertical direction. As shown in Figure 4 , in this case, the two liquid streams output by the two circulation pipelines and the micro-bubble streams output by the two intensified mass transfer devices can stir the reaction liquid in the counterclockwise direction.

[0073] With reference to Figure 1 , Figure 3 , the hydrogenation reactor 8 is provided with multiple baffles 15, the multiple baffles 15 are staggered, and the multiple baffles 15 are located between the baffle 17 and the second intensified mass transfer device group in the vertical direction; the baffles 15 are inclined downward away from the side wall of the hydrogenation reactor 8. In the embodiment, the inlet of the second circulation pipeline 14 is higher than the baffles 15 in the vertical direction.

[0074] With reference to Figure 1 , Figure 5 , the system further comprises 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 the embodiment, the number of filters 11 is two, and the two filters 11 are connected in parallel. The two filters 11 can adopt an open-close application mode to avoid shutdown for cleaning the filter 11.

[0075] As shown in Figure 5As shown, the filter 11 is provided with an arc-shaped filter cloth 20; the arc-shaped filter cloth 20 divides the internal chamber of the filter 11 into a filtering chamber and a filtrate chamber, the filtrate chamber is connected with the product pipeline, and the side wall of the filtering chamber is connected with the hydrogenation reactor 8. A guide plate 21 is arranged at the inlet of the filter 11, and the guide plate 21 is arranged to extend downwardly and tilt toward the arc-shaped filter cloth 20. The reacted material flows upwardly in the hydrogenation reactor 8, flows into the settling tank 10 from the material outlet, and is precipitated, the supernatant is the product 1,3-propanediol, and the lower turbidity 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.

[0076] The embodiment also provides a method for preparing 1,3-propanediol, which applies the above system to prepare 1,3-propanediol.

[0077] The method specifically comprises the following steps:

[0078] Firstly, deionized water is introduced into the first and second intensified mass transfer devices 2 and 5 in the hydration reactor 1, and propenal, N-alkyl amino acid and hydroquinone are added into the hydration reactor 1 according to 5-25%, 5-15% and 0-0.1% of the mass of the hydration reaction liquid, and a hydration reaction is performed under the conditions of a pressure of 0-0.5 MPa (gauge pressure), a temperature of 30-60°C and a time of 2-4 h to generate 3-hydroxypropionaldehyde. The reacted material flows upwardly in the hydration reactor 1, flows into the rotating disc extraction column 6 from the top, and is extracted and separated, and the extraction agent is at least one of methyl tert-butyl ether, diethyl ether and benzene. The extraction theoretical tray number is 3-6, the extraction mode is countercurrent extraction, the oil-water mass ratio is 1.5-5:1, and the extraction temperature is 25-40°C. The separated water phase containing 3-hydroxypropionaldehyde flows into the hydrogenation reactor 8 from the bottom to perform hydrogenation reaction, and the oil phase containing N-alkyl amino acid and unreacted propenal flows into the rectifying column 7 from the top to perform rectification and separation. The propenal produced at the top of the rectifying column 7 flows into the hydration reactor 1 for recycling, the extraction agent produced at the middle section flows into the extraction column for recycling, and the N-alkyl amino acid produced at the bottom flows into the hydration reactor 1 for recycling.

[0079] Then, the powder supported noble metal catalyst is loaded into the hydrogenation reactor 8, hydrogen is introduced into the micro-interface intensified unit of the hydrogenation reactor 8, the pressure of the hydrogenation reaction is controlled to be 2-5 MPa (gauge pressure), the temperature is controlled to be 40-100°C, the space velocity is controlled to be 1-5 h -1 to generate 1,3-propanediol. The reacted material flows upwardly in the hydrogenation reactor 8, flows into the settling tank 10 from the top, and is precipitated, the supernatant is the product 1,3-propanediol, and the lower turbidity 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.

[0080] In this example, the specific process for preparing 1,3-propanediol is as follows: 6.8 kg of deionized water is passed into the first enhanced mass transfer unit of the hydration reactor, 1.5 kg of acrolein is added, and 0.4 kg of N-alkyl amino acid catalyst is added. The reaction is carried out at a pressure of 0.2 MPa (gauge pressure) and a temperature of 55°C for 3 h. The reacted material flows from the bottom to the top of the hydration reactor and is fed into the rotating disc extractor column (5 trays, extraction temperature 30°C) for extraction separation. The water phase containing 3-hydroxypropionaldehyde separated from the top of the column is fed into the hydrogenation reactor for hydrogenation reaction. 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 After 1 h of reaction, the conversion rate of 3-hydroxypropionaldehyde is 99.4%, and the selectivity of 1,3-propanediol is 99.5%.

[0081] In this example, the mass percentage of each component (excluding solvent) in the hydration reaction liquid before extraction, the oil phase after extraction, and the water phase is shown in Table 1.

[0082] Table 1 Mass percentage of each component before and after extraction

[0083]

[0084] Example 2

[0085] The system used in this example is the same as that used in Example 1. The specific process for preparing 1,3-propanediol in this example is as follows: 7.8 kg of deionized water is passed into the first enhanced mass transfer unit of the hydration reactor, 0.8 kg of acrolein is added, and 1.4 kg of N-alkyl amino acid catalyst is added. The reaction is carried out at a pressure of 0.1 MPa (gauge pressure) and a temperature of 35°C for 2 h. The reacted material flows from the bottom to the top of the hydration reactor and is fed into the rotating disc extractor column for extraction separation. The water phase containing 3-hydroxypropionaldehyde separated from the bottom of the column is fed into the hydrogenation reactor for hydrogenation reaction. The hydrogenation reaction is carried out at a pressure of 4 MPa (gauge pressure), a temperature of 60°C, and a space velocity of 1.5 h -1 After 1 h of reaction, the conversion rate of 3-hydroxypropionaldehyde is 97.4%, and the selectivity of 1,3-propanediol is 98.5%.

[0086] Example 3

[0087] The system used in this example is the same as that of Example 1. The specific process for preparing 1,3-propanediol in this example is as follows: 9.2 kg of deionized water is passed into the first intensifier-mass transfer unit of the hydration reactor, 2.0 kg of acrolein and 1.5 kg of N-alkyl amino acid catalyst are added, and the reaction is carried out at a pressure of 0.4 MPa (gauge pressure) and a temperature of 60°C for 2 h. The reacted material flows from the bottom to the top of the hydration reactor and flows into the rotating disc extraction column at the top for extraction separation. The separated water phase containing 3-hydroxypropionaldehyde flows from the bottom of the column into the hydrogenation reactor for hydrogenation reaction. The hydrogenation reaction is carried out at a pressure of 4 MPa (gauge pressure), a temperature of 80°C, and a space velocity of 1.5 h -1 After 1 h of reaction, the conversion rate of 3-hydroxypropionaldehyde is 99.8% and the selectivity of 1,3-propanediol is 99.8%.

[0088] Example 4

[0089] The specific process for preparing 1,3-propanediol in this example is the same as that of Example 1, except that the third intensifier-mass transfer unit is arranged vertically above the second intensifier-mass transfer unit in this example, and the lower end outlet of the third intensifier-mass transfer unit is opposite to the upper end outlet of the fourth intensifier-mass transfer unit. In this example, after 1 h of reaction, the conversion rate of 3-hydroxypropionaldehyde is 98.1% and the selectivity of 1,3-propanediol is 98.3%.

[0090] Example 5

[0091] The specific process for preparing 1,3-propanediol in this example is the same as that of Example 1, except that the outlet of the first circulation pipeline is at the same height as the outlet of the second circulation pipeline. In this example, after 1 h of reaction, the conversion rate of 3-hydroxypropionaldehyde is 99.1% and the selectivity of 1,3-propanediol is 99.2%.

[0092] Comparative Example 1

[0093] The specific process for preparing 1,3-propanediol in this example is the same as that of Example 1, except that the first intensifier-mass transfer unit is not arranged in the hydration reactor and the second intensifier-mass transfer unit is not arranged in the hydrogenation reactor in this example. After 1 h of hydrogenation reaction, the conversion rate of 3-hydroxypropionaldehyde is 76.3% and the selectivity of 1,3-propanediol is 87.4%.

[0094] Comparative Example 2

[0095] In this example, no first enhanced mass transfer unit is installed in the hydration reactor, and no second enhanced mass transfer unit is installed in the hydrogenation reactor. The specific process for preparing 1,3-propanediol in this 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 upwards 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%.

[0096] As can be seen from Examples 1-5, the system of this invention has a high raw material conversion rate in the preparation of 1,3-propanediol, and the selectivity of 1,3-propanediol is good.

[0097] 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.

[0098] 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.

[0099] 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.

[0100] In summary, the system can increase the phase interface mass transfer area between raw materials in the hydration reaction and the hydrogenation reaction of propenal, and improve the raw material conversion rate and the selectivity of 1,3-propanediol by using the first enhanced mass transfer unit arranged in the hydration reactor and the second enhanced mass transfer unit arranged in the hydrogenation reactor.

[0101] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the utility model, and not limited to them; although the utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement to part or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the utility model.

Claims

1. A system for the production of 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 of claim 1, wherein, 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 of claim 2, wherein, 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 of claim 1, wherein, 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.

7. The system according to claim 6, characterized in that, The outlet of the first circulation pipe is located vertically below the outlet of the second circulation pipe.

8. The system according to any one of claims 1-7, characterized in that, The hydrogenation reactor is provided with multiple baffles, which are staggered and located vertically between the baffle and the second enhanced mass transfer unit.

9. The system according to any one of claims 1-7, 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.

10. The system according to any one of claims 1-7, 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.

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