Trickle bed reactor and method for preparing m-phenylenediamine using the same

Abstract

A trickle bed reactor comprises a reactor shell, wherein a liquid distributor, at least one liquid redistributor, and at least one support plate are sequentially arranged from top to bottom, dividing the interior of the reactor shell into a gas chamber, at least two catalyst beds, and a liquid chamber. The catalyst bed is filled with a three-dimensional pulse packing, wherein a gas phase inlet is provided at the top, a liquid outlet is provided at the bottom, and a liquid inlet and a gas outlet are provided on the sidewalls at positions corresponding to the liquid distributor and the liquid chamber, respectively. The three-dimensional pulse packing comprises a three-dimensional pulse tube bundle arranged vertically within the catalyst bed, wherein the three-dimensional pulse tube bundle comprises a plurality of parallel and dispersed three-dimensional pulse tubes, each having a vertical first liquid channel, and a vertical second liquid channel formed between adjacent three-dimensional pulse tubes. A method for preparing m-xylylenediamine using the aforementioned trickle bed reactor is also provided. The trickle bed reactor can improve the turbulence and mass transfer efficiency of the gas-liquid phase within the bed.

Description

Technical Field

[0001] The invention belongs to the technical field of equipment and production, and particularly relates to a trickle bed reactor and a method for preparing m-xylenediamine using the same. Background Art

[0002] The trickle bed reactor is a typical gas-liquid-solid three-phase reactor that can achieve a high conversion rate. It is widely used in chemical processes such as petroleum refining, petrochemicals, and fine chemicals, and is mainly used for reactions such as hydrogenation and oxidation. However, the trickle bed reactor also has the following disadvantages: during small-scale experiments, the radial distribution of the liquid flow at low liquid speeds is uneven, which may cause incomplete wetting of the solid catalyst, uneven temperature distribution, the formation of hot spots, rapid deactivation of the catalyst, or affect the gas-liquid flow state, all of which are not conducive to the operation of the trickle bed reactor. Therefore, it is necessary to improve the trickle bed reactor so that it can be operated at the boundary between the trickle flow zone and the pulse flow zone as much as possible, so that the gas-liquid phase distribution is more uniform and the occurrence of local overheating is avoided.

[0003] Meta-xylylenediamine (m-xylylenediamine) is a colorless liquid that is soluble in water and organic solvents. It is mainly used to manufacture heat-resistant, fast-curing high-performance epoxy resin curing agents. It is a raw material for polyurethane resins and is also used in rubber products, photosensitive plastics, nylon products, lubricants and other fields. The current synthesis route of m-xylylenediamine is mainly a batch method, which cannot be produced on a large scale. The continuous process route is mainly carried out in a trickle bed reactor. However, the gas-liquid two-phase flow rate during the pilot experiment is low and is in the trickle region, which cannot provide accurate and valuable data for pilot or industrial reactors. Therefore, in order to address the problems existing in the current pilot continuous process, it is necessary to seek an improved trickle bed reactor to increase the turbulence of the gas-liquid two-phase during the pilot test, enhance mass transfer and heat transfer, and provide accurate data for the operation of the industrial reactor. Summary of the Invention

[0004] The first object of the present invention is to provide a trickle bed reactor having a three-dimensional pulse packing, which can improve the turbulence degree and mass transfer efficiency of the gas-liquid phase in the bed and is suitable for catalytic hydrogenation reaction;

[0005] A second object of the present invention is to provide a method for preparing m-xylenediamine using the aforementioned trickle bed reactor, which is simple and easy to operate, enhances mass transfer and heat transfer between the gas-liquid-solid three phases, and improves the data accuracy of small-scale experiments.

[0006] In order to achieve the first object of the present invention, the following technical solutions are adopted:

[0007] A trickle bed reactor comprises a reactor shell;

[0008] The reactor shell is provided with a liquid distributor, at least one liquid redistributor, and at least one support plate in sequence from top to bottom, so as to divide the reactor shell into a gas chamber, at least two catalyst beds, and a liquid chamber in sequence from top to bottom; the catalyst bed is filled with a three-dimensional pulse filler;

[0009] The reactor shell is provided with a gas phase inlet on the top, a liquid outlet on the bottom, a liquid inlet on the side wall corresponding to the liquid distributor, and a gas outlet on the side wall corresponding to the liquid cavity;

[0010] The three-dimensional pulse packing includes a three-dimensional pulse tube bundle vertically arranged in the catalyst bed, and the three-dimensional pulse tube bundle includes a plurality of three-dimensional pulse tubes arranged in parallel and dispersedly. The three-dimensional pulse tubes have a vertical first liquid channel, and a vertical second liquid channel is formed between adjacent three-dimensional pulse tubes.

[0011] In the trickle bed reactor of the present invention, preferably, the three-dimensional pulse tube includes contraction segments and expansion segments alternately arranged along its length, and adjacent contraction segments and expansion segments form a pulse unit; the three-dimensional pulse tube includes 50-200 pulse units;

[0012] Preferably, the area of ​​the maximum cross section of the pulse unit is 10-50 mm 2 and / or

[0013] The area ratio of the minimum cross section to the maximum cross section in the pulse unit is 0.01-0.25.

[0014] In the trickle bed reactor of the present invention, preferably, the length ratio of the expansion section to the contraction section is 1 / 3-1; and / or

[0015] The ratio of the specific surface area of ​​the expansion section to the specific surface area of ​​the contraction section is 1-3.

[0016] In the trickle bed reactor of the present invention, preferably, the length of the contraction section is 5-15 mm; and / or

[0017] The specific surface area of ​​the contraction section is 1-5m 2 / m 3 .

[0018] In the trickle bed reactor of the present invention, preferably, in the three-dimensional pulse packing, the three-dimensional pulse tube bundle is arranged in the catalyst bed in the following manner: three adjacent three-dimensional pulse tubes are arranged in an equilateral triangle to form a minimum arrangement unit;

[0019] Preferably, in the minimum arrangement unit, the arrangement directions of two adjacent three-dimensional pulse tubes differ by 120°;

[0020] Preferably, the distance between two adjacent three-dimensional pulse tubes is calculated as L1 according to the distance between their vertical center axes, and the length of the longest side of the largest cross section in the pulse unit is L2, then L1 / L2=0.5-5.

[0021] The trickle bed reactor of the present invention is preferably:

[0022] The material of the three-dimensional pulse filler is any one or more combinations of plastic, metal, ceramic or glass; and / or

[0023] The catalyst bed has a height-to-diameter ratio of 3-8; and / or

[0024] The liquid redistributor is a truncated cone structure.

[0025] To achieve the second object of the present invention, a method for preparing m-xylylenediamine using the aforementioned trickle bed reactor is also provided, the method comprising:

[0026] (1) introducing hydrogen into the trickle bed reactor from the gas phase inlet to activate the catalyst loaded in the catalyst bed;

[0027] (2) introducing the composite solvent containing isophthalonitrile into the trickle bed reactor from the liquid inlet, and causing a catalytic hydrogenation reaction with the introduced hydrogen in the catalyst bed to prepare meta-xylylenediamine, which is output from the liquid outlet.

[0028] In one embodiment, in the method, the pulse frequency of the three-dimensional pulse filler (5) in the trickle bed reactor is 0.01-10s -1 .

[0029] In one embodiment, in the method, the catalyst loaded in the catalyst bed is a nickel-based catalyst;

[0030] Preferably, the nickel-based catalyst is a skeletal catalyst or a supported catalyst, and the nickel content is ≥5 wt%.

[0031] In one embodiment, in the method, the composite solvent comprises a combination of any two or more of tetrahydrofuran, methanol, toluene, cyclohexane, liquid ammonia, and N-methylpyrrolidone; and / or

[0032] In the catalytic hydrogenation reaction, the molar ratio of isophthalonitrile, hydrogen, and composite solvent is 1:(1-10):(2-40); and / or

[0033] In the catalytic hydrogenation reaction, the reaction pressure is 6-20 MPa, and / or the reaction temperature is 50-100°C.

[0034] The beneficial effects of the present invention are:

[0035] (1) The trickle bed reactor of the present invention is provided with a three-dimensional pulse packing. The unique pulse characteristics of the three-dimensional pulse packing can greatly improve the wetting degree of the catalyst, thereby generating "pulsation" in the bed layer, which can improve the turbulence degree and mass transfer efficiency of the gas-liquid phase in the bed layer;

[0036] (2) The trickle bed reactor of the present invention is provided with a liquid redistributor between adjacent catalyst beds. The unique structure of the liquid redistributor enables the liquid to be redistributed, reduces the liquid channeling and gas coalescence, increases the contact area between the gas and liquid phases, and improves the gas-liquid mass transfer efficiency;

[0037] (3) The trickle bed reactor of the present invention, under the combined action of the three-dimensional pulse filler and the liquid redistributor, can enhance the heat and mass transfer between the gas, liquid, and solid phases, making the flow pattern in the bed close to the adjacent areas of trickle flow and pulse flow, thereby making the flow pattern more stable and avoiding the phenomenon of uneven temperature and concentration distribution; it is suitable for catalytic hydrogenation reactions;

[0038] (4) The method of preparing m-xylenediamine using the aforementioned trickle bed reactor of the present invention is simple and easy to operate. Under the combined action of the three-dimensional pulse filler and the liquid redistributor, the degree of catalyst wetting is greatly improved, and the flow pattern in the bed is close to the adjacent areas of trickle flow and pulse flow. The flow pattern is more stable, avoiding the phenomenon of uneven temperature and concentration distribution, and can increase the space velocity of the small-scale test device, improve the data accuracy of the small-scale experiment, thereby providing more accurate data for the industrial device; at the same time, it reduces the process operating conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 1 is a schematic structural diagram of a trickle bed reactor according to one embodiment of the present invention;

[0040] Figure 2 1 is a schematic structural diagram of a pulse unit of a three-dimensional pulse packing in a trickle bed reactor of the present invention in one embodiment;

[0041] Figure 3 It is a schematic diagram of the arrangement of the three-dimensional pulse tubes of the three-dimensional pulse packing in the trickle bed reactor of the present invention in one embodiment (also a schematic diagram of its cross-sectional structure). DETAILED DESCRIPTION

[0042] The technical solutions and effects of the present invention are further described below with reference to specific embodiments / examples and accompanying drawings. The following embodiments / examples are intended only to illustrate the present invention and are not intended to be limited to the following embodiments or examples. Simple modifications to the present invention that utilize the concepts of the present invention fall within the scope of protection claimed herein.

[0043] The present invention provides a trickle bed reactor, such as Figure 1-3 As shown, the trickle bed reactor includes a reactor shell 10;

[0044] The reactor shell 10 is provided with a liquid distributor 2, at least one liquid redistributor 6, and at least one support plate 7 in sequence from top to bottom, dividing the reactor shell into a gas chamber, at least two catalyst beds 4, and a liquid chamber in sequence from top to bottom; the catalyst bed 4 is filled with a three-dimensional pulse filler 5;

[0045] The reactor shell 10 is provided with a gas phase inlet 1 at the top, a liquid outlet 9 at the bottom, a liquid inlet 3 at a position corresponding to the liquid distributor 2 on the side wall, and a gas outlet 8 at a position corresponding to the liquid cavity on the side wall;

[0046] Among them, the three-dimensional pulse packing 5 includes a three-dimensional pulse tube bundle vertically arranged in the catalyst bed 4, and the three-dimensional pulse tube bundle includes a plurality of three-dimensional pulse tubes 51 arranged in parallel and dispersedly. The three-dimensional pulse tubes 51 have a vertical first liquid channel, and a vertical second liquid channel is formed between adjacent three-dimensional pulse tubes 51.

[0047] The trickle bed reactor of the present invention is provided with a three-dimensional pulse filler. The unique pulse characteristics of the three-dimensional pulse filler can greatly improve the wetting degree of the catalyst, thereby generating "pulsation" in the bed layer, which can improve the turbulence degree and mass transfer efficiency of the gas-liquid phase in the bed layer; a liquid redistributor is provided between adjacent catalyst beds, and the unique structure of the liquid redistributor enables the liquid to be dispersed again, reduces the channeling of the liquid and the aggregation of the gas, increases the contact area of ​​the gas-liquid phase, and improves the gas-liquid mass transfer efficiency; under the joint action of the three-dimensional pulse filler and the liquid redistributor, the heat transfer and mass transfer between the gas, liquid and solid phases can be enhanced, so that the flow pattern in the bed layer is close to the adjacent areas of the trickle flow and the pulse flow, thereby making the flow pattern more stable and avoiding the phenomenon of uneven temperature and concentration distribution; and the reactor is suitable for catalytic hydrogenation reactions.

[0048] In one embodiment, the three-dimensional pulse tube 51 includes contraction segments 511 and expansion segments 512 alternately arranged along its length, and adjacent contraction segments 511 and expansion segments 512 form a pulse unit; the three-dimensional pulse tube 51 includes 50-200 pulse units, such as 60, 70, 80, 90, 100, 110, 120, 130, 140, 150, 160, 170, 180 and 190.

[0049] In the present invention, the contraction section 511 refers to a portion whose cross-sectional area decreases from top to bottom, and the expansion section 512 refers to a portion whose cross-sectional area increases from top to bottom.

[0050] In one embodiment, the maximum cross-sectional area of ​​the pulse unit is 10-50 mm 2 , such as 15mm 2 , 20mm 2 , 25mm 2 , 30mm 2 , 35mm 2 , 40mm 2 and 45mm 2 .

[0051] In one embodiment, the area ratio of the minimum cross section to the maximum cross section in the pulse unit is 0.01-0.25, such as 0.03, 0.05, 0.07, 0.1, 0.13, 0.15, 0.17, 0.2, 0.22 and 0.24, thereby effectively forming a pulse.

[0052] In one embodiment, the length ratio of the expansion section 512 to the contraction section 511 is 1 / 3-1, such as 1 / 3, 3 / 8, 1 / 2, 5 / 8, 2 / 3, 3 / 4, 7 / 8 and 1; preferably, it is less than 1 on this basis.

[0053] In the present invention, the lengths of the expansion section 512 and the contraction section 511 refer to their lengths along the length direction of the three-dimensional pulse tube 51 .

[0054] In the present invention, when the length of the expansion section 512 is small, the velocity change rate of the fluid in the expansion section 512 is large, thereby improving the pulse effect.

[0055] In one embodiment, the ratio of the specific surface area of ​​the expansion section 512 to the specific surface area of ​​the contraction section 511 is 1-3, such as 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8 and 2.9; preferably, it is greater than 1 on this basis, so that the fluid can change faster in the expansion section 512, thereby effectively forming a pulse.

[0056] In the present invention, the specific surface area of ​​the expansion section 512 refers to the surface area of ​​the three-dimensional pulse filler per unit volume.

[0057] Those skilled in the art will appreciate that volume and specific surface area are inversely proportional: the larger the volume, the smaller the specific surface area, and conversely, the smaller the volume, the larger the specific surface area. A ratio of the specific surface area of ​​the expansion section 512 to the contraction section 511 of 1-3 indicates that the specific surface area of ​​the expansion section 512 is greater than or equal to the specific surface area of ​​the contraction section 511. Accordingly, the volume of the expansion section 512 is less than or equal to the volume of the contraction section 511. This allows for a greater rate of change in the velocity of the fluid within the expansion section 512, effectively forming a pulse.

[0058] In one embodiment, the length of the contraction section 511 is 5-15 mm, such as 6 mm, 7 mm, 8 mm, 9 mm, 10 mm, 11 mm, 12 mm, 13 mm and 14 mm.

[0059] In one embodiment, the specific surface area of ​​the contraction section 511 is 1-5 m 2 / m 3 , for example 1.5m 2 / m 3 , 2m 2 / m 3 , 2.5m 2 / m 3 , 3m 2 / m 3 , 3.5m 2 / m 3 , 4m 2 / m 3 and 4.5m 2 / m 3 .

[0060] The cross section of the pulse unit can be in any form. In order to improve the pulse effect and thus improve the heat transfer and mass transfer between the gas, liquid and solid phases, in one embodiment, the cross section of the pulse unit is a polygon, preferably a triangle, and more preferably an acute triangle.

[0061] In one embodiment, the angles of the three included angles of the acute triangle are 40-60°, such as 45°, 50° and 55°; 50-70°, such as 55°, 60° and 65°; 60-90°, such as 65°, 70°, 75°, 80° and 85°.

[0062] In one embodiment, in the three-dimensional pulse packing 5 , the three-dimensional pulse tube bundle is arranged in the catalyst bed 4 in the following manner: three adjacent three-dimensional pulse tubes 51 are arranged in an equilateral triangle to form a minimum arrangement unit.

[0063] In one embodiment, in the minimum arrangement unit, the arrangement directions of two adjacent three-dimensional pulse tubes 51 differ by 120°.

[0064] The difference of 120° between the arrangement directions of two adjacent three-dimensional pulse tubes 51 means that, in the smallest arrangement unit arranged in an equilateral triangle, the first corner on a cross section of the first three-dimensional pulse tube 51 is located at point A, the second corner adjacent thereto is located at point B, and the direction from A to B is 0° (also 360°). Then, in the second three-dimensional pulse tube 51 adjacent to the first one, the corresponding direction from A to B is 120° (or -120°); similarly, in the third three-dimensional pulse tube 51 adjacent to the second one, the corresponding direction from A to B is 240° (or -240°). This is equivalent to the smallest arrangement unit of the equilateral triangle arrangement. Compared to the arrangement orientation of the first three-dimensional pulse tube 51, the second three-dimensional pulse tube 51 is rotated 120° clockwise / counterclockwise around its own vertical center axis, and the third three-dimensional pulse tube 51 is rotated 120° clockwise / counterclockwise around its own vertical center axis twice. The arrangement orientations of each two tubes differ by 120°.

[0065] In one embodiment, the distance between two adjacent three-dimensional pulse tubes 51 is calculated as L1 according to the distance between the vertical center axes of the two, and the length of the longest side of the largest cross-section in the pulse unit is L2, then L1 / L2=0.5-5, such as 1, 1.5, 2, 2.5, 3, 3.5, 4 and 4.5.

[0066] In one embodiment, the three-dimensional pulse filler 5 is made of any one or more combinations of plastic, metal, ceramic or glass.

[0067] In one embodiment, the catalyst bed 4 has a height-to-diameter ratio of 3-8, such as 4, 5, 6, and 7.

[0068] In one embodiment, the liquid redistributor 6 is a truncated cone structure.

[0069] The present invention also provides a method for preparing m-xylylenediamine using the aforementioned trickle bed reactor, the method comprising:

[0070] (1) introducing hydrogen into the trickle bed reactor from the gas phase inlet 1 to activate the catalyst loaded in the catalyst bed 4;

[0071] (2) The composite solvent containing isophthalonitrile is introduced into the trickle bed reactor from the liquid inlet 3, and undergoes a catalytic hydrogenation reaction with the introduced hydrogen in the catalyst bed 4 to prepare meta-xylylenediamine, which is output from the liquid outlet 9.

[0072] In one embodiment, in the method, the pulse frequency of the three-dimensional pulse filler 5 in the trickle bed reactor is 0.01-10s -1 , for example 0.02s -1 , 0.05s -1 , 0.1s -1 , 0.15s -1 , 0.2s -1 , 0.5s -1 , 1s -1 , 1.5s -1 , 2s -1 , 2.5s -1 、3s -1 , 3.5s -1 、4s -1 , 4.5s -1 、5s -1 , 5.5s -1 、6s -1 , 6.5s -1 、7s -1 , 7.5s -1 、8s -1 , 8.5s -1 、9s -1 and 9.5s -1 .

[0073] In one embodiment, the catalyst loaded in the catalyst bed 4 is a nickel-based catalyst.

[0074] In one embodiment, the nickel-based catalyst is a skeletal catalyst or a supported catalyst, and the nickel content is ≥5wt%, such as 5.5wt%, 6wt%, 5.5wt%, 7wt%, 7.5wt% and 8wt%.

[0075] In one embodiment, the composite solvent includes a combination of any two or more of tetrahydrofuran, methanol, toluene, cyclohexane, liquid ammonia, and N-methylpyrrolidone.

[0076] In one embodiment, in the catalytic hydrogenation reaction, the molar ratio of isophthalonitrile, hydrogen, and the complex solvent is 1:(1-10, such as 2, 3, 4, 5, 6, 7, 8, and 9):(2-40, such as 3, 5, 10, 15, 20, 25, 30, and 35).

[0077] In one embodiment, in the catalytic hydrogenation reaction, the reaction pressure is 6-20 MPa, such as 8 MPa, 10 MPa, 12 MPa, 14 MPa, 16 MPa and 18 MPa; and / or the reaction temperature is 50-100°C, such as 55°C, 60°C, 65°C, 70°C, 75°C, 80°C, 85°C, 90°C and 95°C.

[0078] The method of the present invention for preparing m-xylylenediamine using the aforementioned trickle bed reactor is simple and easy to operate. Under the combined action of the three-dimensional pulse filler and the liquid redistributor, the degree of catalyst wetting is greatly improved, the flow pattern in the bed is close to the adjacent areas of trickle flow and pulse flow, and the flow pattern is more stable, thereby avoiding the phenomenon of uneven temperature and concentration distribution. The space velocity of the small-scale test device can be increased, and the accuracy of the data of the small-scale experiment is improved, thereby providing more accurate data for industrial equipment; at the same time, the process operating conditions are reduced.

[0079] The sources of raw materials used in the following examples / comparative examples are:

[0080] Isophthalonitrile, >99.99%, TCI Reagent Co., Ltd.;

[0081] Tetrahydrofuran, >99.99%, Xilong Chemical Co., Ltd.

[0082] Liquid ammonia, >99.999%, Air Liquide (Shanghai) Compressed Gas Co., Ltd.;

[0083] Hydrogen, >99.999%, Yantai Mingju New Energy Co., Ltd.

[0084] Catalyst, 10% Ni / supported Al2O3 catalyst, Xunkai Catalyst.

[0085] Test method / standard:

[0086] The conversion rate of isophthalonitrile was analyzed by liquid chromatography external standard method;

[0087] Conversion rate of isophthalonitrile = (molar amount of converted isophthalonitrile) / (molar amount of input isophthalonitrile) × 100%;

[0088] The molar yield of m-phenylenediamine was analyzed by liquid chromatography external standard method; wherein,

[0089] Molar yield of meta-xylylenediamine = (molar amount of meta-xylylenediamine obtained) / (molar amount of isophthalonitrile charged) × 100%.

[0090] Example 1 (S1)

[0091] like Figure 1-3 As shown, a trickle bed reactor A1 includes a reactor shell 10;

[0092] The reactor shell 10 is provided with a liquid distributor 2, two liquid redistributors 6 and a support plate 7 in sequence from top to bottom, dividing the reactor shell into a gas chamber, three catalyst beds 4 and a liquid chamber in sequence from top to bottom; the catalyst bed 4 is filled with a three-dimensional pulse filler 5;

[0093] The reactor shell 10 is provided with a gas phase inlet 1 at the top, a liquid outlet 9 at the bottom, a liquid inlet 3 at a position corresponding to the liquid distributor 2 on the side wall, and a gas outlet 8 at a position corresponding to the liquid cavity on the side wall;

[0094] The three-dimensional pulse packing 5 includes a three-dimensional pulse tube bundle vertically arranged in the catalyst bed 4. The three-dimensional pulse tube bundle includes a plurality of three-dimensional pulse tubes 51 arranged in parallel and dispersedly. The three-dimensional pulse tubes 51 have vertical first liquid channels, and vertical second liquid channels are formed between adjacent three-dimensional pulse tubes 51.

[0095] The three-dimensional pulse tube 51 includes contraction segments 511 and expansion segments 512 alternately arranged along its length, and adjacent contraction segments 511 and expansion segments 512 form a pulse unit. The three-dimensional pulse tube 51 includes 100 pulse units.

[0096] The maximum cross-sectional area of ​​the pulse unit is 25 mm 2 ;

[0097] The ratio of the area of ​​the smallest cross section to the largest cross section in the pulse unit is 0.09;

[0098] The length ratio of the expansion section 512 to the contraction section 511 is 2 / 3;

[0099] The ratio of the specific surface area of ​​the expansion section 512 to the specific surface area of ​​the contraction section 511 is 1.1.

[0100] The length of the contraction section 511 is 9 mm;

[0101] The specific surface area of ​​the contraction section 511 is 1.6 m 2 / m 3 ;

[0102] The cross section of the pulse unit is an equilateral triangle.

[0103] In the three-dimensional pulse packing 5, the three-dimensional pulse tube bundle is arranged in the catalyst bed 4 in the following manner: three adjacent three-dimensional pulse tubes 51 are arranged in an equilateral triangle to form a minimum arrangement unit;

[0104] In the minimum arrangement unit, the arrangement directions of two adjacent three-dimensional pulse tubes 51 differ by 120°;

[0105] The distance between two adjacent three-dimensional pulse tubes 51 is calculated as the distance between their vertical center axes as L1, and the length of the longest side of the largest cross section in the pulse unit is L2, then L1 / L2=1.5;

[0106] The material of the three-dimensional pulse filler 5 is stainless steel;

[0107] The catalyst bed 4 has a height-to-diameter ratio of 5 and a diameter of 30 mm;

[0108] The liquid redistributor 6 is a truncated cone structure.

[0109] The method of preparing m-phenylenediamine B1 by using the trickle bed reactor A1 comprises:

[0110] (1) introducing hydrogen into the trickle bed reactor from the gas phase inlet 1 to activate the catalyst loaded in the catalyst bed 4;

[0111] (2) introducing the composite solvent containing isophthalonitrile into the trickle bed reactor from the liquid inlet 3, and reacting the solvent with the introduced hydrogen in the catalyst bed 4 to produce meta-xylylenediamine B1, which is then output from the liquid outlet 9;

[0112] The catalyst loaded in the catalyst bed 4 is a 10% Ni / supported Al2O3 catalyst;

[0113] The composite solvent is a composite solvent of tetrahydrofuran and liquid ammonia, and the mass ratio of tetrahydrofuran to liquid ammonia is 2:1;

[0114] In the catalytic hydrogenation reaction, the molar ratio of isophthalonitrile, hydrogen, and composite solvent is 1:5:20;

[0115] In the catalytic hydrogenation reaction, the reaction pressure is 6 MPa and the reaction temperature is 70°C.

[0116] The meta-xylylenediamine B1 from the liquid outlet 9 was analyzed by liquid chromatography external standard method. The analysis results are shown in Table 1.

[0117] Example 2 (S2)

[0118] A trickle bed reactor A2, which differs from the trickle bed reactor A1 described in Example 1 only in that:

[0119] The stereo pulse tube 51 includes 50 pulse units;

[0120] The maximum cross-sectional area of ​​the pulse unit is 11 mm 2 ;

[0121] The ratio of the area of ​​the smallest cross section to the largest cross section in the pulse unit is 0.01;

[0122] The length ratio of the expansion section 512 to the contraction section 511 is 1 / 3;

[0123] The ratio of the specific surface area of ​​the expansion section 512 to the specific surface area of ​​the contraction section 511 is 1.4.

[0124] The length of the contraction section 511 is 6 mm;

[0125] The specific surface area of ​​the contraction section 511 is 2.5 m 2 / m 3 .

[0126] Meta-xylylenediamine B2 was prepared using the trickle bed reactor A2 according to the method of Example 1.

[0127] The obtained m-phenylenediamine B2 was analyzed by liquid chromatography external standard method. The analysis results are shown in Table 1.

[0128] Example 3 (S3)

[0129] A trickle bed reactor A3, which differs from the trickle bed reactor A1 described in Example 1 only in that:

[0130] The stereo pulse tube 51 includes 200 pulse units;

[0131] The maximum cross-sectional area of ​​the pulse unit is 48 mm 2 ;

[0132] The ratio of the area of ​​the smallest cross section to the largest cross section in the pulse unit is 0.25;

[0133] The length ratio of the expansion section 512 to the contraction section 511 is 1;

[0134] The ratio of the specific surface area of ​​the expansion section 512 to the specific surface area of ​​the contraction section 511 is 1.

[0135] The length of the contraction section 511 is 13 mm;

[0136] The specific surface area of ​​the contraction section 511 is 1 m 2 / m 3 ;

[0137] The above trickle bed reactor A3 was used to prepare m-xylylenediamine B3 according to the method of Example 1; and the only difference from Example 1 was that:

[0138] The obtained m-phenylenediamine B3 was analyzed by liquid chromatography external standard method. The analysis results are shown in Table 1.

[0139] Example 4 (S4)

[0140] A trickle bed reactor A4, which differs from the trickle bed reactor A1 described in Example 1 only in that:

[0141] The cross section of the pulse unit is an acute triangle; the three included angles of the acute triangle are 50°, 60°, and 70° respectively;

[0142] L1 / L2=2.

[0143] Meta-xylylenediamine B4 was prepared using the trickle bed reactor A4 according to the method of Example 1.

[0144] The obtained m-phenylenediamine B4 was analyzed by liquid chromatography external standard method. The analysis results are shown in Table 1.

[0145] Example 5 (S5)

[0146] The above trickle bed reactor A1 was used to prepare m-xylylenediamine B5 according to the method of Example 1; and the only difference from Example 1 was that:

[0147] The pulse frequency of the three-dimensional pulse filler 5 is 2s -1 ;

[0148] In the catalytic hydrogenation reaction, the reaction pressure is 8 MPa and the reaction temperature is 80°C.

[0149] The obtained m-phenylenediamine B5 was analyzed by liquid chromatography external standard method. The analysis results are shown in Table 1.

[0150] Example 6 (S6)

[0151] A trickle bed reactor A6, which differs from the trickle bed reactor A1 described in Example 1 only in that:

[0152] The cross section of the pulse unit is a right triangle, and the three included angles are 30°, 60°, and 90° respectively;

[0153] L1 / L2=2.

[0154] Meta-xylenediamine B6 was prepared using the trickle bed reactor A6 according to the method of Example 1.

[0155] The obtained m-phenylenediamine B6 was analyzed by liquid chromatography external standard method. The analysis results are shown in Table 1.

[0156] Example 7 (D7)

[0157] A trickle bed reactor A7, which differs from the trickle bed reactor A1 described in Example 1 only in that:

[0158] The maximum cross-sectional area of ​​the pulse unit is 75 mm 2 ;

[0159] The ratio of the area of ​​the smallest cross section to the largest cross section in the pulse unit is 0.36;

[0160] The specific surface area of ​​the contraction section 511 is 0.8 m 2 / m 3 .

[0161] Meta-xylenediamine B7 was prepared using the trickle bed reactor A7 according to the method of Example 1.

[0162] The obtained m-phenylenediamine B7 was analyzed by liquid chromatography external standard method. The analysis results are shown in Table 1.

[0163] Example 8 (S8)

[0164] A trickle bed reactor A8, which differs from the trickle bed reactor A1 described in Example 1 only in that:

[0165] The cross section of the pulse unit is square.

[0166] Meta-xylylenediamine B8 was prepared using the trickle bed reactor A8 according to the method of Example 1.

[0167] The obtained m-phenylenediamine B8 was analyzed by liquid chromatography external standard method. The analysis results are shown in Table 1.

[0168] Comparative Example 1 (D1)

[0169] A trickle bed reactor A1', which differs from the trickle bed reactor A1 described in Example 1 only in that:

[0170] The catalyst bed 4 is not filled with the three-dimensional pulse filler 5 .

[0171] The above trickle bed reactor A1' was used to prepare m-xylylenediamine B1' according to the method of Example 1.

[0172] The obtained m-phenylenediamine B1' was analyzed by liquid chromatography external standard method. The analysis results are shown in Table 1.

[0173] Comparative Example 2 (D2)

[0174] A trickle bed reactor A2', which differs from the trickle bed reactor A1 described in Example 1 only in that:

[0175] The liquid redistributor 6 is not provided in the reactor shell 10 .

[0176] The above trickle bed reactor A2' was used to prepare m-xylylenediamine B2' according to the method of Example 1.

[0177] The obtained m-phenylenediamine B2' was analyzed by liquid chromatography external standard method. The analysis results are shown in Table 1.

[0178] Comparative Example 3 (D3)

[0179] The above trickle bed reactor A1 was used to prepare m-xylylenediamine B3' according to the method of Example 1; the only difference from Example 1 was that:

[0180] The pulse frequency of the three-dimensional pulse filler 5 is 15s -1 .

[0181] The obtained m-phenylenediamine B3' was analyzed by liquid chromatography external standard method. The analysis results are shown in Table 1.

[0182] In Examples 1-8 and Comparative Examples 1-3, the liquid phase material from the liquid outlet 9 was analyzed by liquid chromatography external standard method at the initial time, 2000 hours, and 3000 hours of catalyst operation in the catalytic hydrogenation reaction. The analysis results are shown in Table 1.

[0183] Table 1 Analysis results of the catalytic hydrogenation reaction at different time points

[0184]

[0185] According to the comparison of Examples 1-8 and Comparative Examples 1-3 and the data in Table 1, when the trickle bed reactor of the present invention is used and meta-xylylenediamine is prepared according to the method of the present invention, the conversion rate of isophthalonitrile and the molar yield of meta-xylylenediamine are both high, and a relatively good yield can be maintained for a long time;

[0186] According to the comparison between Example 1 and Comparative Example 1, when the three-dimensional pulse filler 5 is filled in the trickle bed reactor, the conversion rate of isophthalonitrile and the molar yield of meta-xylylenediamine are significantly improved;

[0187] According to the comparison between Example 1 and Comparative Example 2, when the trickle bed reactor of the present invention is used, and the three-dimensional pulse filler 5 and the liquid redistributor 6 are used in the trickle bed reactor, and when meta-xylylenediamine is prepared according to the method of the present invention, the conversion rate of isophthalonitrile and the molar yield of meta-xylylenediamine are both high; if only the three-dimensional pulse filler 5 is used in the trickle bed reactor without the liquid redistributor 6, the conversion rate of isophthalonitrile and the molar yield of meta-xylylenediamine will be slightly reduced;

[0188] According to the comparison between Example 1 and Comparative Example 3, when using the trickle bed reactor of the present invention and preparing m-xylenediamine according to the method of the present invention, the pulse frequency of the three-dimensional pulse filler 5 can affect the conversion rate of isophthalonitrile and the molar yield of m-xylenediamine, as well as the service life of the catalyst.

[0189] Although the present invention has been described in detail through the above preferred embodiments, it should be understood that the above description is not intended to limit the present invention. Those skilled in the art will appreciate that, based on the teachings of this specification, modifications and adjustments may be made to the present invention. Such modifications and adjustments should also be within the scope defined by the claims of the present invention.

Claims

1. A trickle bed reactor, characterized in that The trickle bed reactor comprises a reactor shell (10); The reactor shell (10) is provided with a liquid distributor (2), at least one liquid redistributor (6), and at least one support plate (7) in sequence from top to bottom, so as to divide the reactor shell into a gas chamber, at least two catalyst beds (4), and a liquid chamber in sequence from top to bottom; the catalyst bed (4) is filled with a three-dimensional pulse filler (5); The reactor shell (10) is provided with a gas phase inlet (1) at the top, a liquid outlet (9) at the bottom, a liquid inlet (3) at a position corresponding to the liquid distributor (2) on the side wall, and a gas outlet (8) at a position corresponding to the liquid cavity on the side wall; The three-dimensional pulse packing (5) includes a three-dimensional pulse tube bundle vertically arranged in the catalyst bed (4), the three-dimensional pulse tube bundle includes a plurality of three-dimensional pulse tubes (51) arranged in parallel and dispersedly, the three-dimensional pulse tubes (51) have a vertical first liquid channel, and a vertical second liquid channel is formed between adjacent three-dimensional pulse tubes (51); The three-dimensional pulse tube (51) includes contraction segments (511) and expansion segments (512) alternately arranged along its length direction, and adjacent contraction segments (511) and expansion segments (512) form a pulse unit; the three-dimensional pulse tube (51) includes 50-200 pulse units; The area ratio of the minimum cross section to the maximum cross section in the pulse unit is 0.01-0.

25.

2. The trickle bed reactor according to claim 1, characterized in that The maximum cross-sectional area of ​​the pulse unit is 10-50 mm 2 .

3. The trickle bed reactor according to claim 2, characterized in that The length ratio of the expansion section (512) to the contraction section (511) is 1 / 3-1; and / or The ratio of the specific surface area of ​​the expansion section (512) to the specific surface area of ​​the contraction section (511) is 1-3.

4. The trickle bed reactor according to claim 2 or 3, characterized in that The length of the contraction section (511) is 5-15 mm; and / or The specific surface area of ​​the contraction section (511) is 1-5 m 2 / m 3 .

5. The trickle bed reactor according to claim 2, characterized in that In the three-dimensional pulse packing (5), the three-dimensional pulse tube bundle is arranged in the catalyst bed (4) in the following manner: three adjacent three-dimensional pulse tubes (51) are arranged in an equilateral triangle to form a minimum arrangement unit.

6. The trickle bed reactor according to claim 5, characterized in that In the minimum arrangement unit, the arrangement directions of two adjacent three-dimensional pulse tubes (51) differ by 120°; and / or In the minimum arrangement unit, the distance between two adjacent three-dimensional pulse tubes (51) is calculated as L1 according to the distance between their vertical center axes, and the length of the longest side of the largest cross section in the pulse unit is L2, then L1 / L2=0.5-5.

7. A method for preparing m-xylylenediamine using the trickle bed reactor according to any one of claims 1 to 6, characterized in that: The method comprises: (1) introducing hydrogen into the trickle bed reactor from the gas phase inlet (1) to activate the catalyst loaded in the catalyst bed (4); (2) A composite solvent containing isophthalonitrile is introduced into the trickle bed reactor from the liquid inlet (3), and undergoes a catalytic hydrogenation reaction with the introduced hydrogen in the catalyst bed (4) to prepare meta-xylylenediamine, which is then output from the liquid outlet (9).

8. The method according to claim 7, characterized in that: The pulse frequency of the three-dimensional pulse filler (5) in the trickle bed reactor is 0.01-10 s -1 .

9. The method according to claim 7 or 8, characterized in that The catalyst loaded in the catalyst bed (4) is a nickel-based catalyst.

10. The method according to claim 9, characterized in that: The nickel-based catalyst is a skeleton-type catalyst or a supported catalyst, and the nickel content is ≥5 wt%.

11. The method according to any one of claims 7, 8 and 10, characterized in that The composite solvent comprises a combination of any two or more of tetrahydrofuran, methanol, toluene, cyclohexane, liquid ammonia, and N-methylpyrrolidone; and / or In the catalytic hydrogenation reaction, the molar ratio of isophthalonitrile, hydrogen, and composite solvent is 1:(1-10):(2-40); and / or In the catalytic hydrogenation reaction, the reaction pressure is 6-20 MPa, and / or the reaction temperature is 50-100°C.

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