Quenching absorption tower and separation method of ammoxidation product containing nitrile compounds

Abstract

The invention provides a quenching absorption tower and a separation method of an ammoxidation product containing nitrile compounds. The quenching absorption tower comprises a distribution section, a transition section, a first absorption section and a tower kettle which are communicated from top to bottom, the distribution section comprises at least two third baffles which are distributed at intervals in the axial direction of the quenching absorption tower, a channel is formed between each third baffle and the inner wall of the distribution section, and the channels formed between every two adjacent third baffles and the inner wall of the distribution section are arranged in a staggered manner; the distribution section is provided with a first absorption liquid inlet, and the first absorption liquid inlet is positioned on one side, deviating from the first absorption section, of the channel; and the transition section is provided with a second absorption liquid inlet. The quenching absorption tower provided by the invention is used for separating ammoxidation products containing nitrile compounds, the absorption rate of the nitrile compounds can be improved, and the risk of solidification of the nitrile compounds is reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of quenching absorption, and in particular relates to a quenching absorption tower and a method for separating ammoxidation products containing nitrile compounds. Background Art

[0002] In the chemical industry, nitrile compounds are an important class of organic compounds, which are widely used in synthetic resins, fibers, rubber, medicines, pesticides, dyes, etc. However, in the production process of nitrile compounds, especially in the preparation of isophthalonitrile by ammoxidation of meta-xylene, high-temperature, easily solidified reaction gases containing solid particles are generated.

[0003] As a device for treating high-temperature, solid-containing gases, the quenching absorption tower has gradually attracted attention. The quenching absorption tower quickly cools the high-temperature reaction gas and absorbs the harmful substances in it with the absorption liquid, thereby achieving gas purification and target product recovery. However, the existing quenching absorption tower has a low absorption rate of nitrile compounds and still has the risk of nitrile compounds being easily solidified. Summary of the invention

[0004] The main purpose of the present invention is to provide a quenching absorption tower, which is used to separate ammonia oxidation products containing nitrile compounds, thereby improving the absorption rate of nitrile compounds and reducing the risk of solidification of nitrile compounds.

[0005] The present invention also provides a method for separating ammoxidation products containing nitrile compounds, which can improve the absorption rate of nitrile compounds and reduce the risk of coagulation of nitrile compounds.

[0006] In a first aspect, the present invention provides a quenching absorption tower, comprising a distribution section, a transition section, a first absorption section and a tower bottom connected in sequence;

[0007] The distribution section includes at least two third baffles distributed along the axial direction of the quench absorption tower, a channel is formed between each of the third baffles and the inner wall of the distribution section, and the channels formed between two adjacent third baffles and the inner wall of the distribution section are staggered;

[0008] The distribution section is provided with a first absorption liquid inlet, and the first absorption liquid inlet is located on a side of the channel away from the first absorption section;

[0009] The transition section is provided with a second absorption liquid inlet.

[0010] The quench absorption tower as described above, wherein the first absorption section comprises a first absorption chamber, a second absorption chamber, and a first partition plate spaced between the first absorption chamber and the second absorption chamber; the first absorption chamber and the second absorption chamber are respectively communicated with the transition section, and the first absorption chamber and the second absorption chamber are respectively communicated with the tower kettle;

[0011] The first absorption chamber is provided with a first baffle, the first baffle intersects with the first partition, and the first baffle is provided with a first through hole;

[0012] The second absorption chamber is provided with a second baffle, the second baffle intersects with the first partition, and the second baffle is provided with a second through hole.

[0013] The quenching absorption tower as described above, wherein the distribution section comprises a top plate disposed on a side of the distribution section away from the tower kettle, and a bottom plate disposed on a side of the distribution section facing the tower kettle, and the at least two third baffles are located between the top plate and the bottom plate; wherein the ratio of h1 to h2 is 1:(1-1.2), and / or the ratio of h1 to h3 is 1:(1.1-1.5);

[0014] Wherein, h1 is the distance between the third baffle closest to the top plate and the top plate;

[0015] h2 is the distance between any two adjacent third baffles;

[0016] h3 is the distance between the third baffle closest to the bottom plate and the bottom plate.

[0017] As described above, the quenching absorption tower, the second absorption liquid inlet of the transition section is provided with a jet feed pipeline, and one or more ejectors arranged on the jet feed pipeline, the injection direction of the ejector forms an angle α0 with the direction from the distribution section to the tower bottom, and the α0 is 0 to 60°.

[0018] The quench absorption tower as described above further includes a second absorption section located between the first absorption section and the transition section, and a third absorption section located between the transition section and the distribution section, and a packing section formed by a packing is respectively provided in the second absorption section and the third absorption section.

[0019] The quenching absorption tower as described above, wherein the distribution section, the third absorption section, the second absorption section, the first absorption section and the tower kettle are coaxially arranged;

[0020] and / or, the ratio of the length h4 of the third absorption section in the axial direction of the quench absorption tower to the length h5 of the transition section in the axial direction of the quench absorption tower is 1:(0.1-0.5);

[0021] and / or, the ratio of the length h4 of the third absorption section in the axial direction of the quench absorption tower to the length h6 of the second absorption section in the axial direction of the quench absorption tower is 1:(1-1.2);

[0022] and / or, the ratio of the length h4 of the third absorption section in the axial direction of the quench absorption tower to the length h7 of the first absorption section in the axial direction of the quench absorption tower is 1:(1-1.5);

[0023] and / or, the ratio of the length of the packing section in the third absorption section in the axial direction of the quench absorption tower to the length of the packing section in the second absorption section in the axial direction of the quench absorption tower is 1:(1-3);

[0024] And / or, the filler in the second absorption section includes one or more of ball rings, step rings, metal ring saddles, conjugate rings, and theta rings;

[0025] And / or, the filler in the third absorption section includes one or more of ball rings, metal ring saddles, and theta rings.

[0026] The quench absorption tower as described above, wherein the ratio of the width of the first absorption chamber to the width of the second absorption chamber in the radial direction of the first absorption section is 1:(1-4);

[0027] and / or, the angle α1 formed by the intersection of the first baffle and the first partition is 50-110°;

[0028] and / or, the angle α2 formed by the intersection of the second baffle and the first baffle is 60-120°;

[0029] and / or, the ratio of the inner diameter D1 of the distribution section to the inner diameter D2 of the first absorption section is 1:(1.1-2);

[0030] And / or, the height h8 of the tower kettle is 1100-3000 mm.

[0031] In a second aspect, the present invention provides a method for separating an ammoxidation product containing nitrile compounds, using the quenching absorption tower as described above for separation, the separation method comprising:

[0032] The first part of the absorption liquid enters the distribution section from the first absorption liquid inlet of the distribution section, and after being distributed in the distribution section, flows through the transition section, the first absorption section and the tower bottom in sequence; and the second part of the absorption liquid enters the transition section from the second absorption liquid inlet of the transition section, and flows through the first absorption section and the tower bottom in sequence;

[0033] The ammoxidation product containing nitrile compounds is allowed to enter the first absorption section and contact with the absorption liquid flowing through the first absorption section, so that the nitrile compounds in the ammoxidation product containing nitrile compounds are absorbed by the absorption liquid, and a light component and a heavy component containing the nitrile compounds are respectively generated in the first absorption section; after being output from the first absorption section, the light component flows in the direction from the first absorption section to the distribution section and contacts with the absorption liquid; the heavy component enters the bottom of the tower.

[0034] According to the above-mentioned separation method of the ammoxidation product containing nitrile compounds, the absorption liquid flows through the first absorption chamber and the second absorption chamber of the first absorption section respectively, the ammoxidation product containing nitrile compounds enters the first absorption chamber and the second absorption chamber respectively, the light component produced by the first absorption section includes the first light component produced by the first absorption chamber and the second light component produced by the second absorption chamber, and the heavy component produced by the first absorption section includes the first heavy component produced by the first absorption chamber and the second heavy component produced by the second absorption chamber;

[0035] and / or, the flow rate of the ammoxidation product containing nitrile compounds is 6 t / h to 60 t / h;

[0036] And / or, the heavy component is output from the tower bottom; the flow rate of the heavy component during the process of outputting the heavy component from the tower bottom is 0.006 t / h to 9 t / h;

[0037] And / or, the temperature of the tower bottom is 150°C to 350°C;

[0038] And / or, after the light component is output from the first absorption section, it flows in the direction from the first absorption section to the distribution section and contacts with the absorption liquid, and then produces tail gas in the distribution section, and the tail gas is output from the distribution section, and the temperature of the tail gas is 30° C. to 120° C.;

[0039] and / or, the flow rate of the first part of the absorption liquid is 10 t / h to 35 t / h;

[0040] and / or, the temperature of the first part of the absorption liquid is -20°C to 50°C;

[0041] and / or, the flow rate of the second part of absorption liquid is 0.6 t / h to 15 t / h;

[0042] And / or, the temperature of the second part of absorption liquid is -10°C to 40°C.

[0043] The separation method of the ammoxidation product containing nitrile compounds as described above, wherein the ammoxidation product containing nitrile compounds comprises an ammoxidation reaction product of an unsaturated hydrocarbon, wherein the unsaturated hydrocarbon comprises an olefin and / or an aromatic hydrocarbon, and wherein the olefin comprises an olefin having 1 to 9 carbon atoms;

[0044] And / or, the nitrile compound includes at least one of acrylonitrile, methacrylonitrile, acetonitrile and isophthalonitrile.

[0045] The quenching absorption tower provided by the present invention has staggered channels in the distribution section, the distribution section is provided with a first absorption liquid inlet, and the transition section is provided with a second absorption liquid inlet, which is used to separate the ammoxidation products containing nitrile compounds, thereby improving the absorption rate of nitrile compounds and reducing the risk of solidification of nitrile compounds. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or related technologies, the following briefly introduces the drawings required for use in the embodiments of the present invention or related technologies. Obviously, the drawings described below are only some embodiments of the present invention, and for ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0047] Figure 1 A schematic diagram of the structure of a quenching absorption tower provided by the present invention;

[0048] Figure 2 This is a schematic diagram of the structure of the quenching absorption tower used in Comparative Example 4.

[0049] Description of reference numerals:

[0050] 1-distribution section; 2-third absorption section; 3-transition section; 4-second absorption section; 5-first absorption section; 6-bottom of tower; 7-first absorption chamber; 8-second absorption chamber; 9-first partition; 10-first baffle; 11-second baffle; 12-ejector; 13-third baffle; 1-1-distribution section; 1-2-absorption section; 1-3-quenching section; 1-4-bottom of tower. DETAILED DESCRIPTION

[0051] In order to make the purpose, technical solutions and advantages of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in combination with the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0052] The quench absorption tower plays an important role in the field of industrial gas treatment, especially in the purification process of high-temperature, solid-containing gases. Its core function is to quickly cool the high-temperature reaction gas and reduce the gas temperature, thereby reducing the heat load on subsequent processing equipment. At the same time, the quench absorption tower uses a specific absorption liquid to remove harmful substances in the gas, achieve gas purification and recovery of target products. This technology has broad application prospects in the chemical, petrochemical and environmental protection industries.

[0053] However, existing quench absorption towers face some technical challenges when handling nitrile compounds. Nitrile compounds tend to solidify at low temperatures, which not only increases the complexity of operation, but also may cause blockage of equipment and pipelines, thus affecting the stable operation and efficiency of the system and reducing the absorption rate of nitrile compounds.

[0054] To address these issues, researchers are exploring a variety of improvement strategies. Optimizing the design and operating conditions of the quench absorption tower to enhance mass transfer and heat exchange efficiency can significantly increase the absorption rate of nitrile compounds and reduce the risk of nitrile compound solidification.

[0055] Based on this, in the first aspect, the present invention provides a quenching absorption tower, such as Figure 1 As shown, it includes a distribution section 1, a transition section 3, a first absorption section 5 and a tower bottom 6 connected from top to bottom;

[0056] The distribution section 1 includes at least two third baffles 13 distributed along the axial direction of the quench absorption tower, the third baffles 13 are distributed with regular small holes, and a channel is formed between each third baffle 13 and the inner wall of the distribution section 1, and the channels formed between two adjacent third baffles 13 and the inner wall of the distribution section 1 are staggered;

[0057] The distribution section 1 is provided with a first absorption liquid inlet, which is located on the side of the channel away from the first absorption section 5;

[0058] The transition section 3 is provided with a second absorption liquid inlet.

[0059] In the present invention, the length axis of the quench absorption tower is parallel to the direction from the tower bottom to the distribution section. The third baffle is arranged on the inner wall of the distribution section, that is, the third baffle is connected to the inner wall of the distribution section, the plane where the third baffle is located is basically perpendicular to the axial direction of the quench absorption tower, and the thickness direction of the third baffle is basically parallel to the axial direction of the quench absorption tower. It should be noted that at least part of the distribution section in the circumferential direction of the distribution section is not connected to the third baffle, so that a channel, that is, a gap, is formed between the third baffle and the inner wall of the distribution section, which is conducive to the absorption liquid flowing through the channel and flowing through the transition section, the first absorption section and the tower bottom in sequence along the length direction of the quench absorption tower. "Offset setting" means not being coaxial, that is, on a plane perpendicular to the length direction of the quench absorption tower, the channel formed between two adjacent third baffles and the distribution section does not completely overlap, specifically, it can be partially overlapping, or completely non-overlapping, that is, for any two adjacent third baffles in the length direction of the quench absorption tower, one of the third baffles covers at least a portion of the channel formed between the other third baffle and the side wall of the distribution section, specifically, it can cover a portion of the channel, or cover the entire area of ​​the channel (i.e., completely cover the channel). The first absorption liquid can form more turbulent and eddy regions after passing through the staggered channel, these turbulent and eddy regions not only increase the contact area between the first absorption liquid and the gas, but also make the contact more frequent and sufficient, which can improve the efficiency of mass transfer and heat transfer, thereby improving the absorption rate of nitrile compounds and reducing the risk of solidification of nitrile compounds.

[0060] In some embodiments, Figure 1 As shown, there are three third baffles, which are the first third baffle, the second third baffle, and the third third baffle in sequence from the bottom of the tower to the distribution section, wherein the second third baffle completely covers the channel formed between the first third baffle and the inner wall of the distribution section, and the third third baffle completely covers the channel formed between the second third baffle and the inner wall of the distribution section.

[0061] In the present invention, the first absorption liquid used to absorb nitrile compounds in the ammoxidation product containing nitrile compounds can be, for example, at least one of benzonitrile, m-methylbenzonitrile, aqueous solution, aqueous sulfuric acid solution, and N,N-dimethylformamide, which enters the distribution section through the first absorption liquid inlet and flows through the transition section and the bottom of the tower in sequence through the distribution section.

[0062] In the present invention, the second absorption liquid inlet is located in the transition section between the distribution section and the tower bottom, so that the second absorption liquid enters the transition section from the second absorption liquid inlet and flows through the tower bottom along the axial direction of the quenching absorption tower. Nitrile compounds can be further absorbed to improve the absorption rate and reduce the risk of solidification of nitrile compounds. The second absorption liquid can be the same as the first absorption liquid, for example, it can be at least one of benzonitrile, m-methylbenzonitrile, aqueous solution, sulfuric acid aqueous solution, and N,N-dimethylformamide.

[0063] The quenching absorption tower provided by the present invention has staggered channels in the distribution section, the distribution section is provided with a first absorption liquid inlet, and the transition section is provided with a second absorption liquid inlet, which is used to separate the ammoxidation products containing nitrile compounds, thereby improving the absorption rate of nitrile compounds and reducing the risk of solidification of nitrile compounds.

[0064] In some embodiments of the present invention, the first absorption section 5 includes a first absorption chamber 7, a second absorption chamber 8, and a first partition plate 9 spaced between the first absorption chamber and the second absorption chamber; the first absorption chamber 7 and the second absorption chamber 8 are respectively connected to the transition section 3, and the first absorption chamber 7 and the second absorption chamber 8 are respectively connected to the bottom 6;

[0065] The first absorption chamber 7 is provided with a first baffle 10, the first baffle 10 intersects with the first partition 9, and the first baffle 10 is provided with a first through hole;

[0066] The second absorption chamber 8 is provided with a second baffle plate 11 , which intersects with the first partition plate 9 , and the second baffle plate 11 is provided with a second through hole.

[0067] In the present invention, the first absorption section is provided with a raw material inlet, and the first absorption chamber and the second absorption chamber are respectively connected to the raw material inlet. It should be noted that the first partition is a solid smooth partition, which can reduce the growth rate of the nitrile compound after solidification. The length direction of the first partition, the length direction of the first absorption chamber, the length direction of the second absorption chamber, the length direction of the first absorption section, and the length direction of the quenching absorption tower are parallel to each other. And the first absorption chamber and the second absorption chamber are partially connected. The first partition 9 divides the first absorption section 5 into two absorption chambers, which can increase the contact area and contact time between the absorption liquid and the gas, thereby enhancing the mass transfer effect, and turbulence and eddy currents are more likely to form in the separated absorption chambers, which is conducive to breaking the liquid film and reducing the mass transfer resistance, thereby improving the absorption rate of nitrile compounds and reducing the risk of solidification of nitrile compounds.

[0068] In the present invention, the first through hole on the first baffle plate penetrates the first baffle plate in the thickness direction of the first baffle plate; a plurality of first through holes are distributed on the first baffle plate, and the first through holes are basically evenly distributed on the first baffle plate; one side of the first baffle plate is connected to the side wall of the first absorption chamber, and the other side is connected to the first partition plate; the direction from the side of the first baffle plate connected to the first absorption chamber to the side of the first baffle plate adjacent to the first partition plate intersects with the length direction of the first partition plate, i.e., an angle α1 is formed. One side of the first baffle plate is connected to the first partition plate, and the other side of the first baffle plate extends obliquely in the direction toward the tower kettle until it is connected to the side wall of the first absorption chamber, that is, in the length direction of the quench absorption tower, the connection portion of the first baffle plate and the side wall of the first absorption chamber is located between the connection portion of the first baffle plate and the first partition plate and the tower kettle.

[0069] In the present invention, the second through hole on the second baffle plate penetrates the second baffle plate in the thickness direction of the second baffle plate; a plurality of second through holes are distributed on the second baffle plate, and the second through holes are basically evenly distributed on the second baffle plate; one side of the second baffle plate is connected to the side wall of the second absorption chamber, and the other side is connected to the first partition plate; the direction from the side of the second baffle plate connected to the second absorption chamber to the side of the second baffle plate adjacent to the first partition plate intersects with the length direction of the first partition plate, i.e., an angle α2 is formed. One side of the second baffle plate is connected to the first partition plate, and the other side extends obliquely in the direction toward the tower kettle until it is connected to the side wall of the second absorption chamber, that is, in the length direction of the quench absorption tower, the connection portion of the second baffle plate and the side wall of the second absorption chamber is located between the connection portion of the second baffle plate and the first partition plate and the tower kettle.

[0070] The present invention does not limit the shapes of the first through hole and the second through hole, as long as the absorption liquid can pass through them, for example, they can be one or more of diamond, triangle, circle, ellipse or square.

[0071] In some embodiments of the present invention, the distribution section 1 includes a top plate disposed on a side of the distribution section 1 away from the bottom 6, and a bottom plate disposed on a side of the distribution section 1 facing the bottom 6, and at least two third baffles 13 are located between the top plate and the bottom plate; wherein the ratio of h1 to h2 is 1:(1-1.2), for example, it can be 1:1, 1:1.05, 1:1.1, 1:1.15, 1:1.2 or a range consisting of any two thereof, and / or, the ratio of h1 to h3 is 1:(1.1-1.5), for example, it can be 1:1.1, 1:1.2, 1:1.3, 1:1.4, 1:1.5 or a range consisting of any two thereof;

[0072] Wherein, h1 is the distance between the third baffle 13 closest to the top plate and the top plate; that is, the distance between the third baffle 13 closest to the top plate and the top plate in the length direction of the quench absorption tower.

[0073] h2 is the distance between any two adjacent third baffles 13; that is, the distance between any two adjacent third baffles 13 in the length direction of the quenching absorption tower.

[0074] h3 is the distance between the third baffle 13 closest to the bottom plate and the bottom plate, that is, the distance between the third baffle 13 closest to the bottom plate and the bottom plate in the length direction of the quenching absorption tower.

[0075] Specifically, Figure 1 As shown, the distance between the third third baffle and the top plate is h1, the distance between the third third baffle and the second third baffle is h2, the distance between the second third baffle and the first third baffle is h2, and the distance between the first third baffle and the bottom plate is h3.

[0076] In the present invention, the ratio of h1 to h2 is within the above-mentioned range, which is conducive to the rapid and uniform distribution of the first absorption liquid when it enters the distribution section. The ratio of h1 to h3 is within the above-mentioned range, which is conducive to the first absorption liquid forming an appropriate vortex or reflux area at the bottom of the distribution section, improving the efficiency of mass transfer and heat transfer, and helping to reduce the accumulation of the first absorption liquid on the bottom plate, avoiding the formation of dead zones or local overheating, thereby further improving the absorption rate of nitrile compounds and reducing the risk of solidification of nitrile compounds.

[0077] In some embodiments of the present invention, a jet feed pipeline m and one or more ejectors 12 arranged on the jet feed pipeline m are provided at the second absorption liquid inlet of the transition section 3, and the ejection direction of the ejector 12 forms an angle α0 with the direction from the distribution section 1 to the tower kettle 6, α0 is 0 to 60°, for example, it can be 0°, 10°, 20°, 30°, 40°, 50°, 60° or a range consisting of any two thereof, that is, the length direction of the jet feed pipeline m is substantially perpendicular to the length direction of the quenching absorption tower, and the angle between the ejector 12 and the jet feed pipeline m is α 01 , α 01 30-90°, α 01 The sum of α0 and α1 is substantially equal to 90°.

[0078] It should be noted that the injection direction of the injector in the present invention is toward the tower bottom, that is, the injector injects downward and forms an angle α0 with the direction from the distribution section to the tower bottom.

[0079] The use of the ejector in the present invention can introduce the second absorption liquid into the quenching absorption tower in the form of high-speed injection. This injection method can significantly increase the turbulence between the fluids, promote the mixing of the absorption liquid and the gas or liquid in the tower, and is conducive to accelerating the mass transfer and heat transfer process. In addition, the injection feeding method can make the second absorption liquid enter the tower in the form of smaller droplets or finer mist, increasing the gas-liquid contact area, thereby improving the absorption efficiency. By adjusting the angle α0 between the injection direction and the flow direction of the fluid in the tower, the diffusion range and trajectory of the injection fluid can be accurately controlled. When α0 is between 0 and 60 degrees, the injection fluid can better cover the space in the tower, reduce the problem of uneven fluid distribution, and avoid the formation of dead zones or local overheating.

[0080] In some embodiments of the present invention, the quench absorption tower also includes a second absorption section 4 located between the first absorption section 5 and the transition section 3, and a third absorption section 2 located between the transition section 3 and the distribution section 1, and the second absorption section 4 and the third absorption section 2 are respectively provided with a packing section formed by a packing.

[0081] In the present invention, the second absorption section and the third absorption section are both provided with a packing section, and the provision of the packing section greatly increases the gas-liquid contact area, so that the absorption liquid is in more sufficient contact with the impurities in the ammoxidation product containing nitrile compounds, thereby improving the absorption efficiency, and the presence of the packing promotes the mass transfer process between the gas and the liquid, which helps the nitrile compounds in the ammoxidation product to be more effectively absorbed. In addition, the packing section is conducive to uniformly distributing the ammoxidation product in the tower, avoiding the situation of excessively high or low local concentration, and can also reduce the eddy current and dead corner phenomenon of the fluid in the tower, so that the ammoxidation product can pass through the tower more smoothly, improve the processing efficiency, and further reduce the risk of solidification of the nitrile compound.

[0082] In some embodiments of the present invention, the distribution section 1, the third absorption section 2, the second absorption section 4, the first absorption section 5 and the bottom of the tower 6 are coaxially arranged.

[0083] In some embodiments, the ratio of the length h4 of the third absorption section 2 in the axial direction of the quench absorption tower to the length h5 of the transition section 3 in the axial direction of the quench absorption tower is 1:(0.1-0.5); for example, it can be 1:0.1, 1:0.2, 1:0.3, 1:0.4, 1:0.5 or a range of any two thereof.

[0084] In some embodiments, the ratio of the length h4 of the third absorption section 2 in the axial direction of the quench absorption tower to the length h6 of the second absorption section 4 in the axial direction of the quench absorption tower is 1:(1-1.2); for example, it can be 1:1, 1:1.05, 1:1.1, 1:1.15, 1:2 or a range of any two thereof.

[0085] In some embodiments, the ratio of the length h4 of the third absorption section 2 in the axial direction of the quench absorption tower to the length h7 of the first absorption section 5 in the axial direction of the quench absorption tower is 1:(1-1.5); for example, it can be 1:1, 1:1.1, 1:1.2, 1:1.3, 1:1.4, 1:1.5 or a range consisting of any two of them.

[0086] In some embodiments, the ratio of the length of the packing section in the third absorption section 2 in the axial direction of the quench absorption tower to the length of the packing section in the second absorption section 4 in the axial direction of the quench absorption tower is 1:(1 to 3); for example, it can be 1:1, 1:1.5, 1:2, 1:2.5, 1:3 or a range consisting of any two of them.

[0087] In some embodiments, the packing in the second absorption section 4 includes one or more of ball rings, step rings, metal ring saddles, conjugated rings, and theta carbon rings.

[0088] In some embodiments, the packing in the third absorption section 2 includes one or more of ball rings, metal ring saddles, and theta carbon rings.

[0089] In the present invention, the distribution section, the third absorption section, the second absorption section, the first absorption section and the tower bottom are coaxially arranged, that is, they have the same central axis, which can make the flow path of gas and liquid in the tower as short as possible, reduce flow resistance, improve mass transfer efficiency, increase the absorption rate of nitrile compounds, and reduce the risk of solidification of nitrile compounds.

[0090] By adjusting the length ratio of the third absorption section to the transition section, the second absorption section, and the first absorption section, it is beneficial to reasonably distribute the residence time of the gas and liquid in the tower, so that the gas and liquid have a specific contact time in a specific section, optimize the mass transfer process, further improve the absorption rate of nitrile compounds, and reduce the risk of solidification of nitrile compounds.

[0091] In the present invention, by adjusting the length ratio of the fillers in the second absorption section and the third absorption section, and limiting the specific types of the fillers in the second absorption section and the third absorption section, the mass transfer efficiency can be further improved, the absorption rate of nitrile compounds can be improved, and the risk of coagulation of nitrile compounds can be reduced.

[0092] In some embodiments of the present invention, the ratio of the radial width of the first absorption chamber 7 to the second absorption chamber 8 in the first absorption section 5 is 1:(1-4); for example, it can be 1:1, 1:2, 1:3, 1:4 or a range consisting of any two of them.

[0093] In some embodiments, the angle α1 formed by the intersection of the first baffle 10 and the first partition 9 is 50-110°; for example, it can be 50°, 60°, 70°, 80°, 90°, 100°, 110° or a range consisting of any two thereof.

[0094] In some embodiments, the angle α2 formed by the intersection of the second baffle 11 and the first baffle 9 is 60-120°, for example, 60°, 70°, 80°, 90°, 100°, 110°, 120° or any two thereof.

[0095] In some embodiments, the ratio of the inner diameter D1 of the distribution section 1 to the inner diameter D2 of the first absorption section 5 is 1:(1.1-2); for example, it can be 1:1.1, 1:1.2, 1:1.3, 1:1.4, 1:1.5, 1:1.6, 1:1.7, 1:1.8, 1:1.9, 1:2 or a range consisting of any two of them.

[0096] In some embodiments, the height h8 of the bottom 6 is 1100-3000 mm, for example, 1100 mm, 1200 mm, 1300 mm, 1400 mm, 1500 mm, 1600 mm, 1700 mm, 1800 mm, 1900 mm, 2000 mm, 2500 mm, 3000 mm or a range consisting of any two of them.

[0097] It can be understood that when the first absorption section is cylindrical, the radial direction of the first absorption section refers to any diameter direction of the circular cross section of the first absorption section perpendicular to the length direction of the quench absorption tower. In the present invention, by adjusting the length ratio of the first absorption chamber and the second absorption chamber in the radial direction of the first absorption section, the residence time and contact area of ​​the gas or liquid in each region can be controlled. The appropriate length ratio is conducive to achieving uniform distribution of the fluid in the tower, reducing the situation of excessively high or low local concentrations, and improving the overall absorption effect, that is, improving the absorption rate of nitrile compounds and reducing the risk of solidification of nitrile compounds.

[0098] The design of the angle α1 and the angle α2 in the present invention is within the above-mentioned range, which can guide the fluid to flow in a more stable and uniform manner, reduce the generation of eddies and dead zones, and also affect the speed and direction of the fluid, which helps to achieve more efficient mixing and contact, optimize the contact area and contact time between the gas and liquid phases, thereby improving the mass transfer efficiency, increasing the absorption rate of nitrile compounds, and reducing the risk of solidification of nitrile compounds.

[0099] In the present invention, the inner diameter ratio of the distribution section to the first absorption section is within the above range, which is beneficial to the distribution of the fluid in the tower. The smaller inner diameter of the distribution section can more effectively disperse the fluid into the larger first absorption section, so that the fluid is evenly distributed in the first absorption section, reducing mass transfer resistance, reducing local oversaturation or undersaturation, ensuring the stability of fluid flow in the tower, reducing the occurrence of adverse phenomena such as eddy currents and reflux, making the absorption process more stable and efficient, thereby improving the absorption efficiency of nitrile compounds.

[0100] The tower bottom in the present invention is used to store the absorption liquid after absorbing nitrile compounds. The height of the tower bottom is within the above range, which can make the tower bottom have enough space to store materials, and is also beneficial to optimize the fluid flow and heat and mass transfer process in the tower, thereby improving the overall absorption efficiency.

[0101] In a second aspect, the present invention provides a method for separating an ammoxidation product containing nitrile compounds, using the quenching absorption tower as described above for separation, the separation method comprising:

[0102] The first part of the absorption liquid enters the distribution section 1 from the first absorption liquid inlet of the distribution section 1, and after being distributed in the distribution section 1, it flows through the transition section 3, the first absorption section 5 and the tower bottom 6 in sequence; and the second part of the absorption liquid enters the transition section 3 from the second absorption liquid inlet of the transition section 3, and flows through the first absorption section 5 and the tower bottom 6 in sequence;

[0103] The ammoxidation product containing nitrile compounds is allowed to enter the first absorption section 5 and contact with the absorption liquid flowing through the first absorption section 5, so that the nitrile compounds in the ammoxidation product containing nitrile compounds are absorbed by the absorption liquid, and a light component and a heavy component containing nitrile compounds are respectively produced in the first absorption section 5; after being output from the first absorption section 5, the light component flows in the direction from the first absorption section 5 to the distribution section 1 and contacts with the absorption liquid; the heavy component enters the tower bottom 6.

[0104] In the present invention, the first part of the absorption liquid enters the distribution section from the first absorption liquid inlet of the distribution section, is distributed through the distribution section, that is, sequentially passes through the mutually offset channels formed between the third baffle plate in the distribution section and the side wall of the distribution section, and then sequentially flows through the transition section, the first absorption section, and the tower bottom. The second part of the absorption liquid enters the transition section from the second absorption liquid inlet of the transition section, and then sequentially flows through the first absorption section and the tower bottom.

[0105] The method for separating the ammoxidation product containing nitrile compounds in the present invention adopts the above-mentioned quenching absorption tower for separation, thereby improving the absorption rate of nitrile compounds and reducing the risk of solidification of nitrile compounds.

[0106] In some embodiments, absorption liquid flows through the first absorption chamber 7 and the second absorption chamber 8 of the first absorption section 5, respectively, and ammonia oxidation products containing nitrile compounds enter the first absorption chamber 7 and the second absorption chamber 8, respectively. The light components produced in the first absorption section 5 include the first light components produced in the first absorption chamber 7 and the second light components produced in the second absorption chamber 8, and the heavy components produced in the first absorption section 5 include the first heavy components produced in the first absorption chamber 7 and the second heavy components produced in the second absorption chamber 8.

[0107] The ammoxidation product containing nitrile compounds enters the first absorption section. Since the first absorption section includes the first absorption liquid and the second absorption liquid flowing through, the ammoxidation product containing nitrile compounds contacts the absorption liquid obtained by mixing the first absorption liquid and the second absorption liquid, so that the absorption liquid absorbs the nitrile compounds therein to obtain light components, such as ammonia, nitrogen, oxygen, etc., and heavy components containing nitrile compounds, wherein the heavy components mainly include nitrile compounds and by-products generated when nitrile compounds are synthesized by ammoxidation of olefins or aromatic hydrocarbon raw materials, for example, when the nitrile compound is isophthalonitrile, the by-products include isophthalamide, etc.; when the nitrile compound is acrylonitrile or methacrylonitrile, the by-products include acetonitrile, hydrogen cyanide, ammonium sulfate, etc. After the light components are output from the first absorption section, they flow in the direction from the first absorption section to the distribution section and contact with the absorption liquid. The absorption liquid continues to absorb the nitrile compounds in the light components and finally flows into the bottom of the tower, which can absorb the nitrile compounds to the maximum extent, improve the absorption rate of the nitrile compounds, and reduce the risk of solidification of the nitrile compounds. The heavy components directly enter the bottom of the tower, and the materials in the bottom of the tower can enter the subsequent separation tower and distillation tower. After the nitrile compounds are separated from the heavy components, the nitrile compounds are purified to obtain high-purity nitrile compounds.

[0108] Since the first absorption chamber and the second absorption chamber are respectively connected to the transition section, and the first absorption chamber and the second absorption chamber are respectively connected to the bottom of the tower, the absorption liquid flows through both the first absorption chamber and the second absorption chamber, and enters the ammoxidation product containing nitrile compounds. The absorption liquid absorbs the nitrile compounds in the first absorption chamber and the second absorption chamber, and produces light components and heavy components, respectively.

[0109] In the process of the ammoxidation product containing nitrile compounds entering the first absorption section 5, the flow rate of the ammoxidation product containing nitrile compounds is 6 to 60 t / h; that is, the flow rate is 6 t / h to 60 t / h, for example, it can be 6 t / h, 7 t / h, 8 t / h, 9 t / h, 10 t / h, 20 t / h, 30 t / h, 40 t / h, 50 t / h, 60 t / h or a range consisting of any two of them.

[0110] In some embodiments, the heavy component is output from the bottom 6; the flow rate of the heavy component in the process of outputting the heavy component from the bottom 6 is 0.006 t / h to 9 t / h; for example, it can be 0.006 t / h, 1 t / h, 2 t / h, 3 t / h, 4 t / h, 5 t / h, 6 t / h, 7 t / h, 8 t / h, 9 t / h or a range consisting of any two of them.

[0111] In some embodiments, the temperature of the bottom 6 is 150°C to 350°C; for example, it can be 150°C, 160°C, 180°C, 200°C, 220°C, 250°C, 300°C, 350°C or a range consisting of any two thereof.

[0112] In some embodiments, after the light component is output from the first absorption section 5, it flows in the direction from the first absorption section 5 to the distribution section 1 and contacts with the absorption liquid, and then tail gas is generated in the distribution section 1. The tail gas is output from the distribution section 1, and the temperature of the tail gas is 30°C to 120°C; for example, it can be 30°C, 40°C, 50°C, 60°C, 70°C, 80°C, 90°C, 100°C, 110°C, 120°C or a range composed of any two of them.

[0113] In the process of the first part of the absorption liquid entering the distribution section 1 from the first absorption liquid inlet of the distribution section 1, the flow rate of the first part of the absorption liquid is 10t / h to 35t / h; for example, it can be 10t / h, 20t / h, 25t / h, 30t / h, 35t / h or the range between any two of them.

[0114] In some embodiments, the temperature of the first portion of the absorption liquid is -20°C to 50°C; for example, it can be -20°C, 0°C, 20°C, 35°C, 50°C or any range therebetween.

[0115] In the process of the second part of the absorption liquid entering the transition section 3 from the second absorption liquid inlet of the transition section 3, the flow rate of the second part of the absorption liquid is 0.6t / h to 15t / h; for example, it can be 0.6t / h, 1t / h, 3t / h, 5t / h, 7t / h, 10t / h, 12t / h, 15t / h or a range consisting of any two of them.

[0116] In some embodiments, the temperature of the second portion of the absorption liquid is -10°C to 40°C, for example, -10°C, 0°C, 10°C, 20°C, 30°C, 40°C or any two thereof.

[0117] In the present invention, the flow rate of the ammoxidation product containing nitrile compounds is within the above range, so that the absorption liquid can fully absorb the nitrile compounds and improve the absorption rate; the flow rate ratio of the heavy component to the ammoxidation product is within the above range, which is conducive to controlling the output of the heavy component and can also improve the purity and consistency of the product.

[0118] In the present invention, the distribution section is provided with a tail gas outlet, which is arranged at the top of the distribution section, which is also the top of the quenching absorption tower, and the tail gas is output from the tail gas outlet of the distribution section. The tower bottom temperature and the tail gas temperature are within the above range, which can further avoid the risk of solidification of nitrile compounds.

[0119] The flow rate and temperature of the first part of the absorption liquid and the flow rate and temperature of the second part of the absorption liquid are within the above ranges, which can ensure that there is enough absorption liquid in contact with the ammoxidation product, improve the absorption rate of nitrile compounds, and avoid the risk of solidification of nitrile compounds.

[0120] In some embodiments of the present invention, the ammoxidation product containing nitrile compounds includes an amination reaction product of an unsaturated hydrocarbon, that is, an ammoxidation product of an unsaturated hydrocarbon, the unsaturated hydrocarbon includes an olefin and / or an aromatic hydrocarbon, and the olefin includes an olefin having a carbon number of 1-9; for example, it can be 1, 2, 3, 4, 5, 6, 7, 8, 9 or a range consisting of any two of them.

[0121] In some embodiments, the nitrile compound includes at least one of acrylonitrile, methacrylonitrile, acetonitrile, and isophthalonitrile.

[0122] The present invention limits the ammonia oxidation product containing nitrile compounds entering the quenching absorption tower for separation, so that the ammonia oxidation product is more suitable for separation using the above-mentioned quenching absorption tower. Therefore, the above-mentioned quenching absorption tower has a high absorption rate for nitrile compounds in the ammonia oxidation product and can avoid the risk of solidification of nitrile compounds.

[0123] The technical solution of the present invention is further described below in conjunction with specific embodiments.

[0124] Example 1

[0125] The device used in this embodiment is Figure 1 The quench absorption tower shown includes a distribution section 1; a third absorption section 2; a transition section 3; a second absorption section 4; a first absorption section 5; a tower bottom 6; a first absorption chamber 7; a second absorption chamber 8; a first partition plate 9; a first baffle plate 10; a second baffle plate 11; an ejector 12, and a third baffle plate 13.

[0126] The quenching absorption tower of this embodiment includes a distribution section 1, a third absorption section 2, a transition section 3, a second absorption section 4, a first absorption section 5 and a tower kettle 6 which are connected and coaxially arranged in sequence. The distribution section 1 includes a top plate arranged on the side of the distribution section 1 away from the tower kettle 6, a bottom plate arranged on the side of the distribution section 1 facing the tower kettle 6, and three third baffles 13 distributed along the length direction of the quenching absorption tower between the top plate and the bottom plate, and the first third baffle, the second third baffle, and the third third baffle are arranged in sequence along the direction from the tower kettle 6 to the distribution section 1, wherein the second third baffle completely covers the channel formed between the first third baffle and the side wall of the distribution section 1, and the third third baffle completely covers the channel formed between the second third baffle and the side wall of the distribution section. The distance between the third third baffle and the top plate is h1, the distance between the third third baffle and the second third baffle is h2, the distance between the second third baffle and the first third baffle is h2, the distance between the first third baffle and the bottom plate is h3, the ratio of h1 to h2 is 1:1, the ratio of h1 to h3 is 1:1.1, and h1 is 800 mm. The distribution section 1 is provided with a first absorption liquid inlet, which is located on the side of the channel away from the first absorption section 5.

[0127] The transition section 3 is provided with a second absorption liquid inlet; the second absorption liquid inlet is provided with a jet feed pipeline and 12 ejectors 12 arranged on the jet feed pipeline, and the injection direction of the ejector 12 forms an angle α0 with the direction from the distribution section 1 to the tower bottom 6, and α0 is 0°.

[0128] The second absorption section 4 and the third absorption section 2 are respectively provided with packing sections formed by fillers. The fillers in the second absorption section 4 are θ rings, and the fillers in the third absorption section 2 are θ rings. The ratio of the length of the packing section in the third absorption section 2 in the length direction of the quenching absorption tower to the length of the packing section in the second absorption section 4 in the length direction of the quenching absorption tower is 1:1.05, and the length of the packing section in the third absorption section 2 is 3000 mm.

[0129] The ratio of the length h4 of the third absorption section 2 in the length direction of the quench absorption tower to the length h5 of the transition section 3 in the length direction of the quench absorption tower is 1:0.2; the ratio of the length h4 of the third absorption section 2 in the length direction of the quench absorption tower to the length h6 of the second absorption section 4 in the length direction of the quench absorption tower is 1:1.05; the ratio of the length h4 of the third absorption section 2 in the length direction of the quench absorption tower to the length h7 of the first absorption section 5 in the length direction of the quench absorption tower is 1:1.

[0130] The first absorption section 5 includes a first absorption chamber 7, a second absorption chamber 8, and a first partition plate 9 (without through holes, being a solid smooth partition plate) spaced between the first absorption chamber 7 and the second absorption chamber 8; the first absorption chamber 7 and the second absorption chamber 8 are respectively connected to the transition section 3, and the first absorption chamber 7 and the second absorption chamber 8 are respectively connected to the bottom 6; the first absorption chamber 7 is provided with a first baffle plate 10, the first baffle plate 10 intersects with the first partition plate 9, and the first baffle plate 10 is provided with a first through hole; the second absorption chamber 8 is provided with a second baffle plate 11, the second baffle plate 11 intersects with the first partition plate 9, and the second baffle plate 11 is provided with a second through hole. The ratio of the radial lengths of the first absorption chamber 7 and the second absorption chamber 8 in the first absorption section 5 is 1:1, the angle α1 formed by the intersection of the first baffle 10 and the first partition 9 is 50°, and the angle α2 formed by the intersection of the second baffle 11 and the first partition 9 is 60°; the ratio of the diameter D1 of the distribution section 1 to the diameter D2 of the first absorption section 5 is 1:1.1; the height h8 of the tower bottom 6 is 1100 mm.

[0131] Specifically, the first part of the absorption liquid meta-methyl benzonitrile enters the distribution section 1 from the first absorption liquid inlet of the distribution section 1, the temperature of the first part of the absorption liquid is 50°C, the flow rate is 30 t / h, and after being distributed in the distribution section 1, it flows through the third absorption section 2, the transition section 3, the second absorption section 4, the first absorption section 5 and the bottom 6 in sequence. The second part of the absorption liquid meta-methyl benzonitrile enters the transition section 3 from the second absorption liquid inlet of the transition section 3, the temperature of the second part of the absorption liquid is 40°C, the flow rate is 15 t / h, and it flows through the first absorption section 5 and the bottom 6 in sequence.

[0132] The ammoxidation product containing isophthalonitrile (flow rate is 60 t / h) enters the first absorption section 5 and contacts with the absorption liquid flowing through the first absorption section 5, so that the isophthalonitrile in the ammoxidation product containing isophthalonitrile is absorbed by the absorption liquid, and light components such as meta-xylene, benzonitrile, oxygen, nitrogen, CO2, NH3, HCN, H2O, etc. and meta-methylbenzonitrile solution containing heavy components such as isophthalonitrile and 3-cyanobenzamide are respectively produced in the first absorption section 5; after the light components are output from the first absorption section 5, they flow in the direction from the first absorption section 5 to the distribution section 1 and contact with the absorption liquid, and then tail gas is produced in the distribution section 1, and the tail gas is output from the tail gas outlet at the top of the distribution section 1, and the temperature of the tail gas is 30°C; the heavy components enter the tower bottom 6 and are output from the tower bottom 6, and the flow rate of the heavy components is 9 t / h, wherein the temperature of the tower bottom 6 is 350°C.

[0133] Among them, absorption liquid flows through the first absorption chamber 7 and the second absorption chamber 8 of the first absorption section 5 respectively, and ammonia oxidation products containing isophthalonitrile enter the first absorption chamber 7 and the second absorption chamber 8 respectively. The light components produced in the first absorption section 5 include the first light components produced in the first absorption chamber 7 and the second light components produced in the second absorption chamber 8, and the heavy components produced in the first absorption section 5 include the first heavy components produced in the first absorption chamber 7 and the second heavy components produced in the second absorption chamber 8.

[0134] Example 2

[0135] The apparatus and separation method of Example 2 are basically the same as those of Example 1, except that the ammoxidation product containing acrylonitrile is allowed to enter the first absorption section 5, and the first absorption liquid and the second absorption liquid are water and aqueous sulfuric acid solution, respectively.

[0136] Example 3

[0137] The device and separation method of Example 3 are basically the same as those of Example 1, except that the ratio of h1 to h2 is 1:1.2, and the ratio of h1 to h3 is 1:1.5.

[0138] Example 4

[0139] The device and separation method of Example 4 are basically the same as those of Example 1, except that the angle α0 formed by the injection direction of the ejector 12 and the direction from the distribution section 1 to the bottom of the tower 6 is 60°.

[0140] Example 5

[0141] The device and separation method of Example 5 are basically the same as those of Example 1, except that the ratio of h4 to h5 is 1:0.5, the ratio of h4 to h6 is 1:1.2, and the ratio of h4 to h7 is 1:1.5.

[0142] Example 6

[0143] The apparatus and separation method of Example 6 are basically the same as those of Example 1, except that the ratio of the length of the packing section in the third absorption section 2 to the length of the packing section in the second absorption section 4 is 1:3.

[0144] Example 7

[0145] The device and separation method of Example 7 are basically the same as those of Example 1, except that the ratio of the lengths of the first absorption chamber 7 and the second absorption chamber 8 in the radial direction of the first absorption section 5 is 1:4.

[0146] Example 8

[0147] The device and separation method of Example 8 are basically the same as those of Example 1, except that the angle α1 formed by the intersection of the first baffle plate 10 and the first partition plate 9 is 110°, and the angle α2 formed by the intersection of the second baffle plate 11 and the first partition plate 9 is 120°.

[0148] Example 9

[0149] The apparatus and separation method of Example 9 are basically the same as those of Example 1, except that the ratio of the diameter D1 of the distribution section 1 to the diameter D2 of the first absorption section 5 is 1:2; and the height h8 of the tower bottom 6 is 3000 mm.

[0150] Example 10

[0151] The apparatus and separation method of Example 10 are basically the same as those of Example 1, except that the flow rate of the ammoxidation product containing isophthalonitrile is 6 t / h, the flow rate of the heavy component is 1 t / h, the bottom temperature is 150°C, the tail gas temperature is 120°C, the temperature of the first part of the absorption liquid benzonitrile is -20°C, the flow rate is 10 t / h, and the temperature of the second part of the absorption liquid benzonitrile is -10°C, and the flow rate is 0.6 t / h.

[0152] Comparative Example 1

[0153] The apparatus and separation method of Comparative Example 1 are substantially the same as those of Example 1, except that the third baffle 13 is not provided in the distribution section 1 of the quench absorption tower.

[0154] Comparative Example 2

[0155] The apparatus and separation method of Comparative Example 2 are substantially the same as those of Example 1, except that the quenching absorption tower is not provided with a transition section 3, that is, no second absorption liquid inlet is provided, and the second portion of absorption liquid is not introduced.

[0156] Comparative Example 3

[0157] The apparatus and separation method of Comparative Example 3 are basically the same as those of Example 1, except that the first absorption chamber 5 of the quench absorption tower is not divided into the first absorption chamber 7 and the second absorption chamber 8 by the first partition plate 9, that is, it is one absorption chamber.

[0158] Comparative Example 4

[0159] The quenching absorption tower used in Comparative Example 4 is as follows Figure 2 As shown, from top to bottom, it includes distribution section 1-1, absorption section 1-2, quenching section 1-3, and tower bottom 1-4. The spacing of distribution section 1-1 is h1, which is 800mm, and h2 is 1680mm. The height h3 of absorption section 1-2 is 3100mm, the height h4 of quenching section 1-3 is 3000mm, the diameter D1 of absorption section 1-2 is 2000mm, and the diameter D2 of quenching section 1-3 is 2500mm. The quenching section 1-3 is not filled with fillers. The absorption section 1-2 and the quenching section 1-3 have the same central axis. The height h5 of the tower bottom 1-4 is 1100mm. The operating load of the quenching absorption tower is 1 to 70t / h.

[0160] a) The ammoxidation product containing isophthalonitrile (flow rate is 60t / h) enters the quench absorption tower. The ammoxidation product is cooled by the quench liquid in the quench section and is divided into two parts. One part of the heavy components is captured in the tower bottom 1-4, and its flow rate is 20t / h. The other part of the light components enters the absorption section 1-2, and its flow rate is 40t / h. The heavy components captured in the tower bottom 1-4 are cooled by the quench section heat exchanger and divided into two streams. One stream is sent to the heavy component processing system, and its flow rate is 2t / h. The other stream is sent to the top of the absorption section 1-2 at a flow rate of 18t / h as an absorption liquid to cool and absorb the ammoxidation product gas flow entering the quench absorption tower. The tower bottom liquid level is controlled at 65% based on the tower bottom height h6, and the tower bottom temperature is controlled at 350℃.

[0161] b) The light component in step a) enters the absorption section 1-2, and the isophthalonitrile is absorbed by the absorption liquid. After absorption, the material is divided into two streams, one stream is sent to the isophthalonitrile refining unit, and its flow rate is 18t / h. The other stream is cooled by the absorption section 1-2 heat exchanger and sent to the top of the distribution section 1-1 as an absorption liquid to wash and absorb isophthalonitrile. The tail gas temperature at the top of the distribution section 1-1 is controlled at 30°C. The tail gas not absorbed by the absorption liquid is discharged from the top of the distribution section 1-1, and its flow rate is 40t / h. It is divided into two streams, and the tail gas of the first stream accounting for 30% of the total tail gas is sent to the catalytic incineration reactor for incineration, and is discharged after reaching the national emission standards. The tail gas of the other stream accounting for 70% of the total tail gas is sent to the oxidation reaction system through the circulating tail gas compressor, and the oxidation reaction operation point is controlled to be outside the explosion curve range.

[0162] The calculation formula of the absorption rate is: absorption rate = (the flow rate of the substance in the ammonia oxidation product - the flow rate of the substance in the tail gas) / the flow rate of the substance in the ammonia oxidation product × 100%.

[0163] Continuous use time of the quenching absorption tower: The quenching absorption tower in the above-mentioned embodiment and comparative example is put into production operation. During the production operation, attention is paid to the pressure difference between the inlet and outlet of the tower. When the pressure difference exceeds 100 kPa, it is judged that serious blockage occurs in the tower and stable production cannot be continued, and the tower needs to be stopped for cleaning.

[0164] Table 1

[0165]

[0166]

[0167] As can be seen from Table 1, the quenching absorption tower provided by the present invention has staggered channels in the distribution section, a second absorption liquid inlet is provided in the transition section, and the first absorption section includes a first absorption chamber and a second absorption chamber separated by a first partition, which are used to separate the ammonia oxidation products containing nitrile compounds, thereby improving the absorption rate of nitrile compounds and reducing the risk of solidification of nitrile compounds.

[0168] From the comparison between Example 1 and Comparative Examples 1-4, it can be seen that the quenching absorption tower provided by the present invention has staggered channels in the distribution section, the transition section is provided with a second absorption liquid inlet, and the first absorption section includes a first absorption chamber and a second absorption chamber separated by a first partition, which are used to separate the ammonia oxidation products containing nitrile compounds, thereby improving the absorption rate of nitrile compounds and reducing the risk of solidification of nitrile compounds, thereby extending the service life of the quenching absorption tower.

[0169] When the quenching absorption tower of the present invention is used for production operation, the pressure difference in the tower exceeds 100 kPa after continuous production for 1.5-2 years, indicating that the tower is seriously blocked and stable production cannot be continued, and the tower needs to be stopped for cleaning. When the quenching absorption tower in Comparative Examples 1-4 is used, the pressure difference in the tower exceeds 100 kPa in about half a year, and blockage occurs, requiring the tower to be stopped for maintenance.

[0170] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A quenching absorption tower, characterized in that: It includes a distribution section, a transition section, a first absorption section and a tower kettle which are connected from top to bottom; The distribution section includes at least two third baffles spaced apart and distributed along the axial direction of the quench absorption tower, a channel is formed between each of the third baffles and the inner wall of the distribution section, and the channels formed between two adjacent third baffles and the inner wall of the distribution section are staggered; The distribution section is provided with a first absorption liquid inlet, and the first absorption liquid inlet is located on a side of the channel away from the first absorption section; The transition section is provided with a second absorption liquid inlet.

2. The quenching absorption tower according to claim 1, characterized in that: The first absorption section includes a first absorption chamber, a second absorption chamber, and a first partition plate spaced between the first absorption chamber and the second absorption chamber; the first absorption chamber and the second absorption chamber are respectively communicated with the transition section, and the first absorption chamber and the second absorption chamber are respectively communicated with the tower bottom; The first absorption chamber is provided with a first baffle, the first baffle intersects with the first partition, and the first baffle is provided with a first through hole; The second absorption chamber is provided with a second baffle, the second baffle intersects with the first partition, and the second baffle is provided with a second through hole.

3. The quenching absorption tower according to claim 1, characterized in that: The distribution section comprises a top plate arranged on a side of the distribution section away from the tower bottom, and a bottom plate arranged on a side of the distribution section facing the tower bottom, and the at least two third baffles are located between the top plate and the bottom plate; wherein the ratio of h1 to h2 is 1:(1-1.2), and / or the ratio of h1 to h3 is 1:(1.1-1.5); Wherein, h1 is the distance between the third baffle closest to the top plate and the top plate; h2 is the distance between any two adjacent third baffles; h3 is the distance between the third baffle closest to the bottom plate and the bottom plate.

4. The quenching absorption tower according to claim 1, characterized in that: The second absorption liquid inlet of the transition section is provided with a jet feed pipeline and one or more ejectors arranged on the jet feed pipeline, and the injection direction of the ejector forms an angle α0 with the direction from the distribution section to the bottom of the tower, and α0 is 0 to 60°.

5. The quenching absorption tower according to claim 1, characterized in that: The quench absorption tower further comprises a second absorption section between the first absorption section and the transition section, and a third absorption section between the transition section and the distribution section. The second absorption section and the third absorption section are respectively provided with a packing section formed by a packing.

6. The quenching absorption tower according to claim 5, characterized in that: The distribution section, the third absorption section, the second absorption section, the first absorption section and the tower bottom are coaxially arranged; and / or, the ratio of the length h4 of the third absorption section in the axial direction of the quench absorption tower to the length h5 of the transition section in the axial direction of the quench absorption tower is 1:(0.1-0.5); and / or, the ratio of the length h4 of the third absorption section in the axial direction of the quench absorption tower to the length h6 of the second absorption section in the axial direction of the quench absorption tower is 1:(1-1.2); and / or, the ratio of the length h4 of the third absorption section in the axial direction of the quench absorption tower to the length h7 of the first absorption section in the axial direction of the quench absorption tower is 1:(1-1.5); and / or, the ratio of the length of the packing section in the third absorption section in the axial direction of the quench absorption tower to the length of the packing section in the second absorption section in the axial direction of the quench absorption tower is 1:(1-3); And / or, the filler in the second absorption section includes one or more of ball rings, step rings, metal ring saddles, conjugate rings, and theta rings; And / or, the filler in the third absorption section includes one or more of ball rings, metal ring saddles, and theta rings.

7. The quenching absorption tower according to claim 2, characterized in that: The ratio of the width of the first absorption chamber to the width of the second absorption chamber in the radial direction of the first absorption section is 1:(1-4); and / or, the angle α1 formed by the intersection of the first baffle and the first partition is 50-110°; and / or, the angle α2 formed by the intersection of the second baffle and the first baffle is 60-120°; and / or, the ratio of the inner diameter D1 of the distribution section to the inner diameter D2 of the first absorption section is 1:(1.1-2); And / or, the height h8 of the tower kettle is 1100-3000 mm.

8. A method for separating an ammoxidation product containing nitrile compounds, characterized in that: The separation is carried out using the quenching absorption tower according to any one of claims 1 to 7, wherein the separation method comprises: The first part of the absorption liquid enters the distribution section from the first absorption liquid inlet of the distribution section, and after being distributed in the distribution section, flows through the transition section, the first absorption section and the tower bottom in sequence; and the second part of the absorption liquid enters the transition section from the second absorption liquid inlet of the transition section, and flows through the first absorption section and the tower bottom in sequence; The ammoxidation product containing nitrile compounds is allowed to enter the first absorption section and contact with the absorption liquid flowing through the first absorption section, so that the nitrile compounds in the ammoxidation product containing nitrile compounds are absorbed by the absorption liquid, and a light component and a heavy component containing the nitrile compounds are respectively generated in the first absorption section; after being output from the first absorption section, the light component flows in the direction from the first absorption section to the distribution section and contacts with the absorption liquid; the heavy component enters the bottom of the tower.

9. The method for separating an ammoxidation product containing nitrile compounds according to claim 8, characterized in that: The absorption liquid flows through the first absorption chamber and the second absorption chamber of the first absorption section respectively, the ammoxidation product containing nitrile compounds enters the first absorption chamber and the second absorption chamber respectively, the light component produced by the first absorption section includes the first light component produced by the first absorption chamber and the second light component produced by the second absorption chamber, and the heavy component produced by the first absorption section includes the first heavy component produced by the first absorption chamber and the second heavy component produced by the second absorption chamber; and / or, the flow rate of the ammoxidation product containing nitrile compounds is 6 t / h to 60 t / h; And / or, the heavy component is output from the tower bottom; the flow rate of the heavy component during the process of outputting the heavy component from the tower bottom is 0.006 t / h to 9 t / h; And / or, the temperature of the tower bottom is 150°C to 350°C; And / or, after the light component is output from the first absorption section, it flows in the direction from the first absorption section to the distribution section and contacts with the absorption liquid, and then produces tail gas in the distribution section, and the tail gas is output from the distribution section, and the temperature of the tail gas is 30° C. to 120° C.; and / or, the flow rate of the first part of the absorption liquid is 10 t / h to 35 t / h; and / or, the temperature of the first part of the absorption liquid is -20°C to 50°C; and / or, the flow rate of the second part of absorption liquid is 0.6 t / h to 15 t / h; And / or, the temperature of the second part of absorption liquid is -10°C to 40°C.

10. The method for separating an ammoxidation product containing nitrile compounds according to claim 8 or 9, characterized in that: The ammoxidation product containing nitrile compounds includes an ammoxidation reaction product of an unsaturated hydrocarbon, wherein the unsaturated hydrocarbon includes an olefin and / or an aromatic hydrocarbon, and the olefin includes an olefin having 1 to 9 carbon atoms; And / or, the nitrile compound includes at least one of acrylonitrile, methacrylonitrile, acetonitrile and isophthalonitrile.

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