A quenching absorption column and a separation method of an ammoxidation product containing a nitrile compound

Abstract

The application provides a quenching absorption tower and a separation method of an ammoxidation product containing a nitrile compound, 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 along 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 adjacent two 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 located on the side of the channel away from the first absorption section; and the transition section is provided with a second absorption liquid inlet. The quenching absorption tower is used for separating the ammoxidation product containing the nitrile compound, can improve the absorption rate of the nitrile compound and reduce the risk of solidification of the nitrile compound.

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] Nitriles are an important class of organic compounds in the chemical industry, widely used in a variety of fields, including synthetic resins, fibers, rubber, pharmaceuticals, pesticides, and dyes. However, the production of nitrile compounds, particularly the preparation of isophthalonitrile via the ammoxidation of meta-xylene, generates hot, easily solidified reaction gases containing solid particles.

[0003] As a device for treating high-temperature, solid-laden gases, quench absorption towers have gradually attracted attention. These towers rapidly cool the hot reaction gas and absorb harmful substances with an absorption liquid, thereby purifying the gas and recovering the target product. However, existing quench absorption towers have low nitrile absorption rates and still pose the risk of nitrile solidification. Summary of the Invention

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

[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 quench 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 connected to the transition section, and the first absorption chamber and the second absorption chamber are respectively connected to 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 quench absorption tower as described above, wherein the distribution section includes a top plate provided on a side of the distribution section facing away from the tower kettle, and a bottom plate provided 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 is provided with a jet feed pipeline and one or more ejectors provided on the jet feed pipeline at the inlet of the second absorption liquid of the transition section. The injection direction of the ejector forms an angle α0 with the direction along 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 the second absorption section and the third absorption section are respectively provided with a packing section formed by a packing.

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

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

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

[0023] and / or, a ratio of a length of the packing section in the third absorption section in the axial direction of the quench absorption tower to a 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 partition is 60 to 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 a nitrile compound, using the quenching absorption tower as described above for separation, the separation method comprising:

[0032] The first portion 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 sequentially through the transition section, the first absorption section, and the tower bottom; and the second portion of the absorption liquid enters the transition section from the second absorption liquid inlet of the transition section, and flows sequentially through the first absorption section and the tower bottom;

[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] In the above-described method for separating an ammoxidation product containing nitrile compounds, the absorption liquid flows through each of the first absorption chamber and the second absorption chamber of the first absorption section, and each of the first absorption chamber and the second absorption chamber enters the ammoxidation product containing nitrile compounds, the light component produced in the first absorption section includes a first light component produced in the first absorption chamber and a second light component produced in the second absorption chamber, and the heavy component produced in the first absorption section includes a first heavy component produced in the first absorption chamber and a second heavy component produced in 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 discharged from the tower bottom; the flow rate of the heavy component during the process of discharging 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 fraction is output from the first absorption section, it flows in the direction from the first absorption section to the distribution section and contacts the absorption liquid, thereby generating 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 portion of absorption liquid is -20°C to 50°C;

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

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

[0043] The method for separating 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 nitrile compounds solidifying. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] 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. Those skilled in the art can also derive other drawings based on these drawings without inventive effort.

[0047] Figure 1 A schematic structural diagram 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; 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. DETAILED DESCRIPTION

[0051] To make the objectives, technical solutions, and advantages of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only 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 making creative efforts shall fall within the scope of protection of the present invention.

[0052] Quench absorption towers play a vital role in industrial gas processing, particularly in the purification of high-temperature, solid-laden gases. Their core function is to rapidly cool high-temperature reaction gases, reducing their temperature and thereby reducing the heat load on subsequent processing equipment. Furthermore, quench absorption towers utilize specialized absorbents to remove harmful substances from the gas, achieving gas purification and recovery of target products. This technology holds broad application prospects in the chemical, petrochemical, and environmental protection industries.

[0053] However, existing quench absorption towers face several technical challenges when processing nitrile compounds. Nitriles tend to solidify at low temperatures, which not only complicates operations but can also cause blockages in equipment and pipelines, impacting system stability and efficiency and reducing nitrile absorption rates.

[0054] To address these issues, researchers are exploring various 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 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 regularly distributed with small holes. A channel is formed between each third baffle 13 and the inner wall of the distribution section 1. 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 longitudinal axis of the quenching 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 substantially perpendicular to the axial direction of the quenching absorption tower, and the thickness direction of the third baffle is substantially parallel to the axial direction of the quenching absorption tower. It should be noted that at least a portion of the circumferential area of ​​the distribution section is not connected to the third baffle, so that a channel, i.e., 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 longitudinal direction of the quenching absorption tower. "Offset arrangement" means not being coaxial, that is, on a plane perpendicular to the length direction of the quenching absorption tower, the channels formed between two adjacent third baffles and the distribution section do not completely overlap, and specifically can be partially overlapping or completely non-overlapping, that is, for any two adjacent third baffles in the length direction of the quenching absorption tower, one of the third baffles covers at least a portion of the channel formed between the other third baffle and the sidewall of the distribution section, and specifically can cover a portion of the channel, or cover the entire area of ​​the channel (i.e., completely cover the channel). After passing through the staggered channel, the first absorption liquid can form more turbulent and eddy regions. 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, thereby improving the efficiency of mass transfer and heat transfer, thereby improving the absorption rate of nitrile compounds and reducing the risk of nitrile compounds solidifying.

[0060] In some embodiments, as 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 along the direction from the bottom of the tower to the distribution section. Among them, 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 for absorbing nitrile compounds in the ammoxidation product containing nitrile compounds can be, for example, at least one of benzonitrile, m-methylbenzonitrile, an aqueous solution, an aqueous sulfuric acid solution, and N,N-dimethylformamide. It 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 bottom of the tower, allowing the second absorption liquid to enter the transition section from the second absorption liquid inlet and flow through the bottom of the tower in the axial direction of the quenching absorption tower. This can further absorb nitrile compounds, improve the absorption rate, and reduce the risk of nitrile compound solidification. 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, an aqueous solution, an aqueous sulfuric acid 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 nitrile compounds solidifying.

[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 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 11 , which intersects with the first partition plate 9 , and the second baffle 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 communicated with the raw material inlet. It should be noted that the first partition plate is a solid smooth partition plate, which can reduce the growth rate of the nitrile compound after solidification. The length direction of the first partition plate, 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 communicated. The first partition plate 9 separates 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 current 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 the nitrile compound and reducing the risk of the nitrile compound solidification.

[0068] In the present invention, the first through-holes on the first baffle extend through the first baffle in the thickness direction of the first baffle. The first baffle is provided with a plurality of first through-holes, which are substantially evenly distributed across the first baffle. One side of the first baffle is connected to the sidewall of the first absorption chamber, and the other side is connected to the first partition. A direction from the side of the first baffle connected to the first absorption chamber to the side of the first baffle adjacent to the first partition intersects the length direction of the first partition, forming an angle α1. One side of the first baffle is connected to the first partition, and the other side extends obliquely toward the bottom of the tower until it connects to the sidewall of the first absorption chamber. That is, along the length direction of the quench absorption tower, the connection between the first baffle and the sidewall of the first absorption chamber is located between the connection between the first baffle and the first partition and the bottom of the tower.

[0069] In the present invention, the second through-holes on the second baffle extend through the second baffle in the thickness direction of the second baffle; the second baffle is provided with a plurality of second through-holes, which are substantially evenly distributed across the second baffle; one side of the second baffle is connected to the sidewall of the second absorption chamber, and the other side is connected to the first partition; the direction from the side of the second baffle connected to the second absorption chamber to the side of the second baffle adjacent to the first partition intersects with the length direction of the first partition, forming an angle α2. The second baffle has one side connected to the first partition, and the other side extends obliquely toward the bottom of the tower until it connects to the sidewall of the second absorption chamber. That is, along the length direction of the quench absorption tower, the connection between the second baffle and the sidewall of the second absorption chamber is located between the connection between the second baffle and the first partition and the bottom of the tower.

[0070] The present invention does not limit the shapes of the first through hole and the second through hole, as long as they can allow the absorption liquid to pass through. 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 provided on a side of the distribution section 1 facing away from the bottom 6, and a bottom plate provided 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, if 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, 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 line m is provided at the second absorption liquid inlet of the transition section 3, and one or more ejectors 12 are provided on the jet feed line m. The injection direction of the ejector 12 forms an angle α0 with the direction from the distribution section 1 to the tower kettle 6, and α0 is 0 to 60°. For example, it can be 0°, 10°, 20°, 30°, 40°, 50°, 60° or a range of any two thereof. That is, the length direction of the jet feed line m is substantially perpendicular to the length direction of the quench absorption tower, and the angle between the ejector 12 and the jet feed line m is α 01 , α 01 is 30-90°, α 01 The sum of α and α0 is basically equal to 90°.

[0078] It should be noted that the ejection direction of the ejector in the present invention is toward the tower bottom, that is, the ejector ejects 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 enables the introduction of the second absorption liquid into the quench absorption tower in the form of a high-speed jet. This jetting method can significantly increase the turbulence between the fluids, promote mixing of the absorption liquid with the gas or liquid in the tower, and facilitate the acceleration of mass and heat transfer processes. In addition, the jet feeding method allows the second absorption liquid to enter the tower in the form of smaller droplets or a finer mist, increasing the gas-liquid contact area and thus improving 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 injected fluid can be precisely controlled. When α0 is between 0 and 60 degrees, the injected fluid can better cover the space within the tower, reducing the problem of uneven fluid distribution and avoiding the formation of dead zones or localized overheating.

[0080] In some embodiments of the present invention, the quench absorption tower further 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, both the second and third absorption sections are provided with packing sections. The provision of the packing sections significantly increases the gas-liquid contact area, allowing for more complete contact between the absorption liquid and the impurities in the ammoxidation product containing nitrile compounds, thereby improving absorption efficiency. The presence of the packing section promotes mass transfer between the gas and the liquid, contributing to more efficient absorption of the nitrile compounds in the ammoxidation product. Furthermore, the packing section facilitates uniform distribution of the ammoxidation product within the tower, avoiding localized concentrations of excessively high or low concentrations. It also reduces eddy currents and dead spots within the tower, allowing the ammoxidation product to pass more smoothly through the tower, improving processing efficiency and further reducing the risk of nitrile compound solidification.

[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 consisting of any two of them.

[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 to 1.2); for example, it can be 1:1, 1:1.05, 1:1.1, 1:1.15, 1:2 or a range consisting of any two of them.

[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 to 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 filler 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 shorten the flow path of gas and liquid in the tower, reduce flow resistance, improve mass transfer efficiency, increase the absorption rate of nitrile compounds, and reduce the risk of nitrile compounds solidifying.

[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 rationally 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 nitrile compound solidification.

[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 increased, and the risk of nitrile compound coagulation can be reduced.

[0092] In some embodiments of the present invention, the ratio of the width of the first absorption chamber 7 to the width of the second absorption chamber 8 in the radial direction of 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 partition 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 is 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 to 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, increasing the absorption rate of nitrile compounds and reducing the risk of nitrile compounds solidifying.

[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 vortices 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 nitrile compounds solidifying.

[0099] In the present invention, the ratio of the inner diameter of the distribution section to the first absorption section is within the above-mentioned 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 the fluid flow in the tower, reducing the occurrence of adverse phenomena such as eddy currents and backflows, making the absorption process more stable and efficient, and thus improving the absorption efficiency of nitrile compounds.

[0100] The tower kettle in the present invention is used to store the absorption liquid after absorbing nitrile compounds. The height of the tower kettle is within the above range, which can provide enough space for storing materials in the tower kettle, and is also beneficial to optimizing 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 a nitrile compound, using the quenching absorption tower as described above for separation, the separation method comprising:

[0102] The first portion 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, flows sequentially through the transition section 3, the first absorption section 5 and the tower bottom 6; and the second portion of the absorption liquid enters the transition section 3 from the second absorption liquid inlet of the transition section 3, and flows sequentially through the first absorption section 5 and the tower bottom 6;

[0103] The ammoxidation product containing nitrile compounds enters the first absorption section 5 and contacts 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; the light component is output from the first absorption section 5 and 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 portion of the absorption liquid enters the distribution section from the first absorption liquid inlet, is distributed through the distribution section, that is, sequentially passes through the mutually offset channels formed between the third baffle and the sidewall of the distribution section, and then sequentially flows through the transition section, the first absorption section, and the bottom of the tower. The second portion of the absorption liquid enters the transition section from the second absorption liquid inlet, and then sequentially flows through the first absorption section and the bottom of the tower.

[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 the nitrile compounds and reducing the risk of solidification of the 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 by the first absorption section 5 include the first light components produced by the first absorption chamber 7 and the second light components produced by the second absorption chamber 8, and the heavy components produced by the first absorption section 5 include the first heavy components produced by the first absorption chamber 7 and the second heavy components produced by the second absorption chamber 8.

[0107] The ammonia oxidation product containing the nitrile compound enters the first absorption section, and because the first absorption section includes the first absorption liquid and the second absorption liquid flowing therethrough, the ammonia oxidation product containing the nitrile compound is mixed with the absorption liquid after the first absorption liquid and the second absorption liquid, so that the absorption liquid absorbs the nitrile compound therein, to obtain light components, such as ammonia, nitrogen, oxygen, and the like, and heavy components containing the nitrile compound, wherein the heavy components mainly include the nitrile compound, and by-products generated when the nitrile compound is synthesized by ammonia oxidation of the olefin or the aromatic hydrocarbon raw material, for example, when the nitrile compound is isophthalonitrile, the by-products include isophthalic acid, and the like; when the nitrile compound is acrylonitrile or methacrylonitrile, the by-products include acetonitrile, hydrogen cyanide, ammonium sulfate, and the like. The light components flow from the first absorption section to the distribution section in the direction from the first absorption section to the distribution section, and are in contact with the absorption liquid, the absorption liquid continues to absorb the nitrile compound in the light components, and finally flows into the column still, so that the nitrile compound can be maximally absorbed, the absorption rate of the nitrile compound is improved, and the risk of solidification of the nitrile compound is reduced. The heavy components directly enter the column still, and the material in the column still can enter the subsequent separation column and the rectification column, the nitrile compound is separated from the heavy components, and the nitrile compound is purified, to obtain a nitrile compound with high purity.

[0108] Because the first absorption chamber and the second absorption chamber are respectively in communication with the transition section, and the first absorption chamber and the second absorption chamber are respectively in communication with the column still, the absorption liquid flows through the first absorption chamber and the second absorption chamber, and enters the ammonia oxidation product containing the nitrile compound, and the absorption liquid respectively absorbs the nitrile compound in the first absorption chamber and the second absorption chamber, and respectively generates light components and heavy components.

[0109] In the process of the ammonia oxidation product containing the nitrile compound entering the first absorption section 5, the flow rate of the ammonia oxidation product containing the nitrile compound is 6-60 t / h; that is, the flow rate is 6 t / h-60 t / h, for example, which 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 formed by any two of them.

[0110] In some embodiments, the heavy components are output from the column still 6; in the process of the heavy components being output from the column still 6, the flow rate of the heavy components is 0.006 t / h-9 t / h; for example, which 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 formed by any two of them.

[0111] In some embodiments, the temperature of the column still 6 is 150°C-350°C; for example, which can be 150°C, 160°C, 180°C, 200°C, 220°C, 250°C, 300°C, 350°C, or a range formed by any two of them.

[0112] In some embodiments, after the light component is output from the first absorption section 5, it flows along the direction from the first absorption section 5 to the distribution section 1 and contacts with the absorption liquid, and then produces tail gas 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 of any two thereof.

[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-mentioned range, which allows the absorption liquid to 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-mentioned range, which is conducive to controlling the yield of the heavy component and also improves the purity and consistency of the product.

[0118] In the present invention, the distribution section is provided with an exhaust gas outlet, which is located at the top of the distribution section, which is also the top of the quench absorption tower, and the exhaust gas is output from the exhaust gas outlet of the distribution section. The tower bottom temperature and the exhaust gas temperature are within the above ranges, 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 sufficient absorption liquid to contact 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 in the range of 1, 2, 3, 4, 5, 6, 7, 8, 9 or any two thereof.

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

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

[0123] The technical solution of the present invention is further described below with reference to 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 9; a first baffle 10; a second baffle 11; an ejector 12, and a third baffle 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 bottom 6, which are sequentially connected and coaxially arranged. The distribution section 1 includes a top plate disposed on the side of the distribution section 1 facing away from the tower bottom 6, a bottom plate disposed on the side of the distribution section 1 facing the tower bottom 6, and three third baffles 13 located between the top and bottom plates and distributed along the length of the quenching absorption tower. The first third baffle, the second third baffle, and the third third baffle are arranged in order from the tower bottom 6 to the distribution section 1. 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, and 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. A first absorption liquid inlet is provided in distribution section 1, located on the side of the channel facing away from first absorption section 5.

[0127] The transition section 3 is provided with a second absorption liquid inlet; a spray feed pipeline and 12 sprayers 12 provided on the spray feed pipeline are arranged at the second absorption liquid inlet, and the spray direction of the sprayers 12 forms an included angle a0 with the direction along the distribution section 1 to the tower kettle 6, and a0 is 0°.

[0128] The second absorption section 4 and the third absorption section 2 are respectively provided with a packing section formed by packing, the packing in the second absorption section 4 is a theta ring, the packing in the third absorption section 2 is a theta ring, 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 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 quenching absorption tower to the length h5 of the transition section 3 in the length direction of the quenching absorption tower is 1:0.2; the ratio of the length h4 of the third absorption section 2 in the length direction of the quenching absorption tower to the length h6 of the second absorption section 4 in the length direction of the quenching absorption tower is 1:1.05; and the ratio of the length h4 of the third absorption section 2 in the length direction of the quenching absorption tower to the length h7 of the first absorption section 5 in the length direction of the quenching 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 (not provided with a through hole, and is 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 communicated with the transition section 3, and the first absorption chamber 7 and the second absorption chamber 8 are respectively communicated with the tower kettle 6; the first absorption chamber 7 is provided with a first baffle 10 intersecting with the first partition plate 9, and the first baffle 10 is provided with a first through hole; the second absorption chamber 8 is provided with a second baffle 11 intersecting with the first partition plate 9, and the second baffle 11 is provided with a second through hole. The ratio of the length of the first absorption chamber 7 to the length of the second absorption chamber 8 in the radial direction of the first absorption section 5 is 1:1, the included angle a1 formed by the intersection of the first baffle 10 and the first partition plate 9 is 50°, the included angle a2 formed by the intersection of the second baffle 11 and the first partition plate 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, and the height h8 of the tower kettle 6 is 1100 mm.

[0131] Specifically, the first portion of the absorption liquid, m-methylbenzonitrile, enters distribution section 1 from the first absorption liquid inlet. The first portion of the absorption liquid has a temperature of 50°C and a flow rate of 30 t / h. After distribution in distribution section 1, the first portion of the absorption liquid sequentially flows through the third absorption section 2, transition section 3, second absorption section 4, first absorption section 5, and bottom 6. The second portion of the absorption liquid, m-methylbenzonitrile, enters transition section 3 from the second absorption liquid inlet. The second portion of the absorption liquid has a temperature of 40°C and a flow rate of 15 t / h. The second portion of the absorption liquid sequentially flows through the first absorption section 5 and bottom 6.

[0132] The ammoxidation product containing isophthalonitrile (with a flow rate of 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 a 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 discharged 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 produce tail gas in the distribution section 1, which is discharged from the tail gas outlet at the top of the distribution section 1, and the tail gas temperature is 30°C; the heavy components enter the tower bottom 6 and are discharged 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, the absorption liquid flows through the first absorption chamber 7 and the second absorption chamber 8 of the first absorption section 5 respectively, and the ammonia oxidation product containing isophthalonitrile enters the first absorption chamber 7 and the second absorption chamber 8 respectively. The light component generated by the first absorption section 5 includes the first light component generated by the first absorption chamber 7 and the second light component generated by the second absorption chamber 8, and the heavy component generated by the first absorption section 5 includes the first heavy component generated by the first absorption chamber 7 and the second heavy component generated by 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 enters 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] Example 4

[0140] Example 5

[0141] Example 5 is substantially the same as the device and separation method 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] Example 6 is substantially the same as the device and separation method 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] Example 7 is substantially the same as the device and separation method of Example 1, except that the ratio of the length of the first absorption chamber 7 to the length of the second absorption chamber 8 in the radial direction of the first absorption section 5 is 1:4.

[0146] Example 8

[0147] Example 8 is substantially the same as the device and separation method of Example 1, except that the angle a1 formed by the intersection of the first baffle 10 and the first partition 9 is 110°, and the angle a2 formed by the intersection of the second baffle 11 and the first partition 9 is 120°.

[0148] Example 9

[0149] Example 9 is substantially the same as the device and separation method 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 kettle 6 is 3000 mm.

[0150] Example 10

[0151] Example 10 is substantially the same as the device and separation method of Example 1, except that the flow rate of the ammonia oxidation product containing isophthalonitrile is 6 t / h, the flow rate of the heavy component is 1 t / h, the tower kettle 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, 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 basically 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 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 comprises a distribution section 1-1, an absorption section 1-2, a quenching section 1-3, and a bottom reactor 1-4. The spacing h1 of the distribution section 1-1 is 800 mm, and h2 is 1680 mm. The height h3 of the absorption section 1-2 is 3100 mm, and the height h4 of the quenching section 1-3 is 3000 mm. The diameter D1 of the absorption section 1-2 is 2000 mm, and the diameter D2 of the quenching section 1-3 is 2500 mm. The quenching section 1-3 is unpacked. The absorption section 1-2 and the quenching section 1-3 share the same central axis. The height h5 of the bottom reactor 1-4 is 1100 mm. This quenching absorption tower has an operating load of 1 to 70 t / h.

[0160] a) The ammoxidation product containing isophthalonitrile (at a flow rate of 60 t / h) enters the quench absorption tower. In the quench section, the ammoxidation product is cooled by the quench liquid and separated into two parts. One heavy component is captured in the bottom 1-4 at a flow rate of 20 t / h, while the other light component enters the absorption section 1-2 at a flow rate of 40 t / h. The heavy component captured in the bottom 1-4 is cooled in the quench heat exchanger and then separated into two streams. One stream is sent to the heavy component treatment system at a flow rate of 2 t / h, and the other stream is sent to the top of the absorption section 1-2 at a flow rate of 18 t / h to serve as absorption liquid to cool the ammoxidation product gas stream entering the quench absorption tower. The bottom liquid level is controlled at 65% of the bottom height h6, and the bottom temperature is controlled at 350°C.

[0161] b) The light component in step a) enters absorption section 1-2, where 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 at a flow rate of 18 t / h. The other stream is cooled in the heat exchanger of absorption section 1-2 and then sent to the top of distribution section 1-1 at a flow rate of 8 t / h to be used as the absorption liquid for washing and absorbing the isophthalonitrile. The tail gas temperature at the top of distribution section 1-1 is controlled at 30°C. The tail gas not absorbed by the absorption liquid is discharged from the top of distribution section 1-1 at a flow rate of 40 t / h and is divided into two streams. The first stream, which accounts for 30% of the total tail gas, is sent to a catalytic incineration reactor for incineration and discharged after meeting national emission standards. The other stream, which accounts for 70% of the total tail gas, is sent to the oxidation reaction system through a circulating tail gas compressor to control the oxidation reaction operating point outside the explosion curve range.

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

[0163] Continuous use time of the quenching absorption tower: The quenching absorption towers in the above embodiments and comparative examples were put into production operation. During the production operation, attention was paid to the pressure difference between the inlet and outlet of the tower. When the pressure difference exceeded 100 kPa, it was determined that serious blockage occurred in the tower and stable production could not continue, requiring the tower 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 ammoxidation 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 quench 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 ammoxidation 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 quench 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 1.5-2 years of continuous production, indicating that the tower is seriously blocked and stable production cannot be continued, requiring shutdown and cleaning. However, 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, indicating blockage and requiring shutdown 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 above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above 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 rapid cooling absorption tower, characterized in that: It includes a distribution section, a transition section, a first absorption section and a tower kettle 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 rapid cooling 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 bottom of the tower; 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 rapid cooling absorption tower according to claim 1, characterized in that The distribution section includes a top plate provided on a side of the distribution section facing away from the tower kettle, and a bottom plate provided 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); 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 rapid cooling 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. The injection direction of the ejector forms an angle α0 with the direction along the distribution section to the tower bottom, and the α0 is 0 to 60°.

5. The rapid cooling absorption tower according to claim 1, characterized in that The quench absorption tower 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. The second absorption section and the third absorption section are respectively provided with a packing section formed of a packing.

6. The rapid cooling 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, a ratio of a length h4 of the third absorption section in the axial direction of the quench absorption tower to a length h5 of the transition section in the axial direction of the quench absorption tower is 1:(0.1-0.5); and / or, a ratio of a length h4 of the third absorption section in the axial direction of the quench absorption tower to a length h6 of the second absorption section in the axial direction of the quench absorption tower is 1:(1-1.2); and / or, a ratio of a length h4 of the third absorption section in the axial direction of the quench absorption tower to a length h7 of the first absorption section in the axial direction of the quench absorption tower is 1:(1-1.5); and / or, a ratio of a length of the packing section in the third absorption section in the axial direction of the quench absorption tower to a 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 rapid cooling 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 partition is 60 to 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 performed using the quenching absorption tower according to any one of claims 1 to 7, wherein the separation method comprises: The first portion 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 sequentially through the transition section, the first absorption section, and the tower bottom; and the second portion of the absorption liquid enters the transition section from the second absorption liquid inlet of the transition section, and flows sequentially through the first absorption section and the tower bottom; 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, wherein: The absorption liquid flows through the first absorption chamber and the second absorption chamber of the first absorption section, respectively, and 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 a first light component produced by the first absorption chamber and a second light component produced by the second absorption chamber, and the heavy component produced by the first absorption section includes a first heavy component produced by the first absorption chamber and a 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 discharged from the tower bottom; the flow rate of the heavy component during the process of discharging 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 fraction is output from the first absorption section, it flows in the direction from the first absorption section to the distribution section and contacts the absorption liquid, thereby generating 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 portion of absorption liquid is -20°C to 50°C; and / or, the flow rate of the second portion of absorption liquid is 0.6 t / h to 15 t / h; And / or, the temperature of the second portion 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, wherein: 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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