Absorption device having opposite spray liquid inlets and manufacturing method for nitrile

Abstract

The present invention relates to an absorption device having opposite spray liquid inlets and a manufacturing method for nitrile. The absorption device can maximize the absorption rate of ammonia and reduce the penetration of ammonia. The absorption device of the present invention comprises a shell and a plurality of spraying devices arranged in layers in the central axis direction of the absorption device at a preset vertical distance, wherein each spraying device independently comprises a spray liquid inlet, a first spraying pipe in fluid communication with the spray liquid inlet, a plurality of second spraying pipes in fluid communication with the first spraying pipe and extending towards two sides of the first spraying pipe perpendicularly to the first spraying pipe, a plurality of third spraying pipes in fluid communication with the second spraying pipes and extending towards two sides of the second spraying pipes perpendicularly to the second spraying pipes, and a nozzle located at the tail end of the third spraying pipes and in fluid communication with the third spraying pipes, wherein when the absorption device is transversely cut in the direction perpendicular to the central axis of the absorption device to obtain the cross section, the projections of at least one selected from among the first spraying pipe, the second spraying pipes and the third spraying pipes of one of the plurality of spraying devices and of another of the plurality of spraying devices on the cross section basically overlap, and the included angle between the projections of the spray liquid inlets of the one spraying device and of the another spraying device on the cross section is 180 degrees.

Description

Absorption device with opposite spray liquid inlets and method for manufacturing nitrile Technical Field

[0001] The present invention relates to the technical field of gas absorption, and more particularly to an absorption device with opposing spray liquid inlets and a method for producing nitrile. Background Art

[0002] Ammoniation or ammoxidation process generates the process route of nitriles accordingly. In order to convert unstripped gases such as hydrocarbons as much as possible, generally unstripped gas ammonia is excessive, i.e., ammonia and unstripped gas hydrocarbons mol ratio is greater than 1. As in propylene ammoxidation, the ammonia ratio (ammonia and propylene mol ratio) is 1.10-1.35. As in aromatic hydrocarbon ammoxidation, the ammonia ratio (ammonia and aromatic hydrocarbon mol ratio) is 4-8. Therefore, unreacted ammonia must be contained in the reactor outlet tail gas. On the one hand, as in the acrylonitrile production process, acrylonitrile etc. are easily polymerized under alkaline conditions in the reaction gas. Even if a small amount of unreacted ammonia escapes, it is also easy to cause pollution to the environment. Therefore, in ammoniation or ammoxidation process, it is necessary to utilize absorption unit (generally referred to as ammonia absorber or quench tower) to remove the unreacted ammonia in the gas phase with acid or water. This process is very necessary.

[0003] With the development of production technology, production loads are constantly increasing. Large-scale and scaled-up equipment is the future development trend. The higher the equipment load, the larger the equipment, including the ammonia absorber, will be. It is known that in the ammonia absorber, the circulating liquid (spraying liquid) is dispersed through the spraying device into the ammonia absorber, where it contacts the ammonia-containing gas in a countercurrent manner and absorbs it, thereby removing the excess ammonia in the gas phase.

[0004] Patent CN105425849 removes excess ammonia by adjusting the pH of the ammonia absorber effluent and adding acid. Patent CN1199940 improves gas-liquid two-phase mass and heat transfer by adding internal components to the bottom of the ammonia absorber, essentially addressing the problem of uniform distribution of the ammonia-containing gas phase. However, ammonia breakthrough, meaning a small amount of ammonia still escapes from the ammonia absorber, inevitably results in product loss in subsequent refining and separation units or causes environmental pollution.

[0005] In the ammonia absorption method of the prior art, after the absorption device has been running for a long period of time, the ammonia content in the absorbed tail gas increases significantly compared to the initial stage of operation.

[0006] Summary of the Invention

[0007] The inventors of the present invention discovered that because the spray liquid inlet of existing devices is on the same side, as the operating cycle of the device increases, after the spray liquid is recycled, solid impurities or other heavy components with higher viscosity, such as sediments, accumulate and adhere to the inner wall of the spray pipeline and nozzle of the spray device, causing the liquid flow resistance to increase continuously, resulting in insufficient pressure in the spray device nozzle and poor atomization effect. The farther away from the spray liquid inlet, the more serious the accumulation problem. After a long period of operation, the degree of accumulation at different positions of the spray device varies, resulting in different degrees of spray liquid atomization of different nozzles. In areas with poor atomization, the ammonia slip phenomenon becomes significant.

[0008] The inventors of the present invention analyzed the accumulation degree of easily deposited matter in various parts of the spraying device as the operating cycle becomes longer and its influence on the atomization effect, and comprehensively considered the complementarity between areas with different atomization degrees (different degrees of deterioration) of different spraying devices. It was found that by setting up multiple layers of spraying devices and making the upper and lower projections of different spraying devices overlap and the spray liquid inlets opposite to each other, it is possible to make areas with different atomization degrees correspond to each other and compensate for each other, so as to achieve overall uniform atomization.

[0009] The inventors of the present invention also found that since the spray liquid in the prior art is sprayed in the same rotation direction, during the downward process of the spray liquid, the droplets formed by one spray liquid come into contact with the droplets formed by another spray liquid, causing the droplet particle size to increase, and the effective area of ​​gas-liquid contact is reduced, resulting in a decrease in the utilization rate of the acid, and at the same time, more ammonia escape.

[0010] The inventors of the present invention have discovered that this problem can be solved by horizontally arranging the spray liquid inlets of one spray device and another spray device, and more preferably by controlling the rotational spraying direction of the spray liquid of the two adjacent nozzles. The present invention is based on this discovery.

[0011] Specifically, the present invention relates to the following aspects.

[0012] 1. An absorption device, comprising a shell and a plurality of (e.g., 2-10, preferably 4-8) spraying devices arranged in layers at predetermined vertical intervals along the central axis of the absorption device, wherein each of the spraying devices independently comprises a spraying liquid inlet, a first spraying pipe in fluid communication with the spraying liquid inlet, a plurality of (e.g., 10-26, preferably 12-22) second spraying pipes in fluid communication with the first spraying pipe and extending perpendicularly to the first spraying pipe on both sides thereof, a plurality of (e.g., 10-26, preferably 12-22) second spraying pipes in fluid communication with the second spraying pipe and extending perpendicularly to the second spraying pipe on both sides thereof 4-26, preferably 6-22) third spray pipes, and a nozzle located at the end of the third spray pipe and in fluid communication with the absorption device, wherein when the absorption device is cut across in a direction perpendicular to the central axis of the absorption device to obtain a cross section, the projections of at least one (preferably all) of one of the multiple spray devices and another of the multiple spray devices selected from the first spray pipe, the second spray pipe and the third spray pipe on the cross section substantially coincide, and the angle between the projections of the spray liquid inlets of the one spray device and the other spray device on the cross section is 180°.

[0013] 2. The absorption device described in any of the preceding or following aspects, wherein the plurality of second spray pipes extend perpendicularly to the first spray pipe and substantially parallel to its opposite sides along the horizontal direction, and / or the plurality of third spray pipes extend perpendicularly to the second spray pipe and substantially parallel to its opposite sides along the horizontal direction.

[0014] 3. The absorption device according to any of the preceding or following aspects, wherein the inner diameter of the first spray pipe is 160-480 mm (preferably 200-450 mm) and the length is 4500-11500 mm (preferably 4800-10500 mm), and / or the multiple second spray pipes are the same as or different from each other, and the inner diameters are each independently 30-150 mm (preferably 40-120 mm) and the lengths are each independently 1200-5750 mm (preferably 1800-5250 mm), and / or the multiple third spray pipes are the same as or different from each other, and the inner diameters are each independently 10-60 mm (preferably 15-50 mm) and the lengths are each independently 160-325 mm (preferably 175-300 mm).

[0015] 4. The absorption device according to any of the preceding or following aspects, wherein the nozzles are identical or different, and the inner diameter (referring to the nozzle outlet) is independently 3-20 mm (preferably 6-14 mm), and the spraying angle is independently 65-120° (preferably 70-100° mm).

[0016] 5. The absorption device according to any of the preceding or following aspects, wherein on the first spray pipe, the horizontal spacing between two adjacent second spray pipes is 640-1300 mm (preferably 700-1200 mm), and / or, on the same second spray pipe, the horizontal spacing between two adjacent third spray pipes is 320-650 mm (preferably 350-600 mm), and / or, on two adjacent second spray pipes, the straight-line distance M between the end of any third spray pipe on one second spray pipe and the end of any third spray pipe on another adjacent second spray pipe is not less than 320 mm (preferably not less than 350 mm).

[0017] 6. The absorption device according to any one of the preceding or following aspects, wherein the nozzles are the same or different from each other, and the spraying liquid spraying rate is independently 0.5-7.5 t / h (preferably 0.9-6.5 t / h).

[0018] 7. The absorption device described in any of the preceding or following aspects, wherein among all the spraying devices, the angle between the projections of the spray liquid inlets of any two odd-numbered spraying devices on the cross section is 0°, the angle between the projections of the spray liquid inlets of any two even-numbered spraying devices on the cross section is 0°, and the angle between the projections of the spray liquid inlets of any odd-numbered spraying device and any even-numbered spraying device on the cross section is 180°.

[0019] 8. The absorption device according to any one of the preceding or following aspects, wherein the inner diameter of the absorption device is 4.5-11.5 m (preferably 4.8-10.5 m).

[0020] 9. The absorption device described in any of the preceding or following aspects, wherein the projections of all nozzles of the one spraying device and the other spraying device on the cross section substantially overlap, and / or the two nozzles whose projections substantially overlap have the same spray diameter.

[0021] 10. The absorption device according to any one of the preceding or following aspects, wherein the nozzle comprises a nozzle inlet, a rotation chamber and a nozzle outlet, wherein the rotation chamber is configured such that the spray liquid entering from the nozzle inlet leaves the nozzle outlet in a rotating manner after passing through the rotation chamber.

[0022] 11. The absorption device according to any one of the preceding or following aspects, wherein the diameter of the rotating chamber is independently 10.0-55.0 mm (preferably 13.0-45.0 mm), and / or the two nozzles whose projections substantially overlap have the same spray liquid rotation direction.

[0023] 12. The absorption device according to any one of the preceding or following aspects, wherein on at least one (preferably all) of the second spray pipes, two adjacent (preferably all) nozzles located on the same side of the second spray pipe are constructed so that the spray liquid is sprayed in the same rotation direction.

[0024] 13. The absorption device according to any one of the preceding or following aspects, wherein all nozzles on opposite sides of two adjacent second spray pipes are constructed so that the spray liquid is sprayed in opposite rotation directions.

[0025] 14. The absorption device described in any of the preceding or following aspects, wherein on at least one (preferably all) of the second spray pipes, at least one (preferably all) nozzles located on one side of the second spray pipe are constructed so that the spray liquid is sprayed in a rotation direction A, and at least one (preferably all) nozzles located on the opposite other side of the second spray pipe are constructed so that the spray liquid is sprayed in a rotation direction B, wherein the rotation direction A is opposite to the rotation direction B.

[0026] 15. The absorption device according to any one of the preceding or following aspects, wherein the rotation direction A is clockwise and the rotation direction B is counterclockwise.

[0027] 16. The absorption device described in any of the preceding or following aspects, wherein among all the nozzles of the spraying device, the number of nozzles spraying the spray liquid in the rotation direction A is equal to or substantially equal to the number of nozzles spraying the spray liquid in the rotation direction B.

[0028] 17. The absorption device according to any one of the preceding or following aspects, wherein the vertical distance between two adjacent spraying devices (measured as the vertical distance between the spraying liquid inlets of the spraying devices) is 650-1350 mm (preferably 750-1200 mm).

[0029] 18. A method for producing a nitrile, comprising a step of subjecting a hydrocarbon feedstock to an ammoxidation reaction to produce a reaction product containing the nitrile (referred to as a reaction step), and a step of spraying a spray liquid onto the reaction product to cool the reaction product (referred to as a cooling step), wherein the spray liquid is sprayed onto the reaction product in an absorption device described in any of the preceding or following aspects.

[0030] 19. The production method according to any one of the preceding or following aspects, wherein in the cooling step, the spraying liquid contacts the reaction product in a countercurrent manner.

[0031] 20. The manufacturing method according to any one of the preceding or following aspects, wherein in the cooling step, the flow ratio of the spray liquid to the reaction product is 15-25:1.

[0032] 21. The production method according to any of the preceding or following aspects, wherein in the reaction step, the hydrocarbon feedstock is propylene, the molar ratio of propylene / ammonia / air (calculated as molecular oxygen) is 1:1.1-1.3:1.8-2.0, the reaction temperature is 420-440°C, the reaction pressure (gauge pressure) is 0.03-0.14 MPa, and the catalyst weight hourly space velocity is 0.06-0.15 h -1 Alternatively, the hydrocarbon feedstock is isobutylene, the molar ratio of isobutylene / ammonia / air (as molecular oxygen) is 1:1.3-1.6:2.2-2.8, the reaction temperature is 395-420°C, the reaction pressure (gauge pressure) is 0.03-0.14 MPa, and the catalyst weight hourly space velocity is 0.08-0.17 h -1 .

[0033] 22. The manufacturing method of any of the preceding or following aspects, wherein during the cooling step, the spraying liquid cools the temperature of the reaction product from 195-235°C to 81-86°C, and / or, during the cooling step, the spraying liquid reduces the ammonia content of the reaction product to below 150 ppm.

[0034] Technical Effects

[0035] According to the present invention, even if the operation is carried out for a long period (such as continuous operation for 18 months or even longer), the ammonia content in the absorbed exhaust gas does not increase significantly compared with the initial operation period, and a good ammonia absorption effect can be maintained for a long period.

[0036] According to the present invention, even in long-term operation (such as continuous operation for 18 months or even longer), the total acid consumption can still be maintained at a low level with a small increase (such as below 3%).

[0037] According to the present invention, the gas-liquid contact is sufficient, the ammonia absorption effect is good, and the amount of acid used can be reduced.

[0038] According to the present invention, the acidic circulating liquid can neutralize more ammonia in the gas phase and reduce the escape of ammonia from the ammonia absorption tower. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] FIG1 is a schematic front view of an ammonia absorption tower in the prior art.

[0040] FIG2 is a schematic front view of an ammonia absorption tower in the prior art.

[0041] 3A and 3B are schematic front views of an ammonia absorption tower according to the present invention.

[0042] 4A and 4B are schematic front views of an ammonia absorption tower according to the present invention.

[0043] FIG5 is a schematic top view of the spraying device of the present invention.

[0044] 6A and 6B are schematic top views of the spraying device of the present invention.

[0045] 7A and 7B are schematic top views of the spraying device of the present invention.

[0046] 8A and 8B are schematic top views of comparative spraying devices.

[0047] 9A and 9B are schematic top and front views of a nozzle in the prior art.

[0048] 10A and 10B are a schematic top view and a detailed top view of a spraying device in the prior art.

[0049] FIG. 11A is a top view / front view schematic diagram of two rotation modes of the nozzle of the present invention.

[0050] FIG. 11B is a schematic top view of the spraying device.

[0051] FIG. 11C is a detailed top view of a spraying device according to the present invention.

[0052] FIG. 11D is a detailed top view of another spraying device according to the present invention.

[0053] FIG. 11E is a detailed top view of another spraying device according to the present invention.

[0054] Explanation of the reference numerals: 1: Ammonia absorber 2: Ammonia absorber internal component demister 3: Ammonia absorber internal component spraying device, 3a-3f are spraying devices 4: Ammonia absorber internal component gas distributor 5: Ammonia absorber internal component spraying device, 5a-5b are spraying devices 6: Upper section circulating pump 7: Lower section circulating pump 8: Ammonia-containing gas feed 9: Ammonia absorber gas phase discharge 10: Upper section water replenishment 11: Lower section wastewater discharge 12: Upper section ammonium salt solution discharge 13: Lower section circulating liquid 14: Upper section circulating liquid 15: Acid-containing solution 16: Circulating liquid 17: Circulating pump 18: Spraying device inlet 19: Spraying device first spraying pipe 20a, 20b: Spraying device second spraying pipe 21: Spraying device third spraying pipe 22: Spraying device atomizing nozzle DETAILED DESCRIPTION

[0055] The specific embodiments of the present invention are described in detail below. However, it should be noted that the protection scope of the present invention is not limited by these specific embodiments, but is determined by the claims in the appendix.

[0056] All publications, patent applications, patents, and other references mentioned in this specification are incorporated herein by reference. Unless otherwise defined, all technical and scientific terms used in this specification have the meanings commonly understood by those skilled in the art. In the event of conflict, the definitions in this specification will prevail.

[0057] When this specification uses the prefix "well known to those skilled in the art", "prior art" or similar terms to introduce materials, substances, methods, steps, devices or components, the objects introduced by the prefix include those commonly used in the art when this application is filed, but also include those that are not commonly used at present but will become generally recognized in the art to be suitable for similar purposes.

[0058] In the context of this specification, by substantially it is meant that the deviation does not exceed 20%, preferably does not exceed 10% or 5%.

[0059] Unless otherwise specified, all percentages, parts, ratios, etc. mentioned in this specification are based on weight and pressure is gauge pressure.

[0060] In the context of this specification, any two or more embodiments of the present invention may be arbitrarily combined, and the technical solutions thus formed belong to part of the original disclosure of this specification and also fall within the scope of protection of the present invention.

[0061] In the context of this specification, all technical details not mentioned are directly applicable to relevant information known in the art.

[0062] According to one embodiment of the present invention, it relates to an absorption device, in particular an ammonia absorption tower or a quenching tower.

[0063] According to one embodiment of the present invention, the absorption device comprises a shell and a plurality of (eg 2-10, preferably 4-8) spraying devices arranged in layers at predetermined vertical intervals along the central axis of the absorption device.

[0064] According to one embodiment of the present invention, each of the spraying devices independently includes a spray liquid inlet, a first spray pipe fluidically connected to the spray liquid inlet, a plurality of (e.g., 10-26, preferably 12-22) second spray pipes fluidically connected to the first spray pipe and extending perpendicularly to the first spray pipe to both sides thereof, a plurality of (e.g., 4-26, preferably 6-22) third spray pipes fluidically connected to the second spray pipe and extending perpendicularly to the second spray pipe to both sides thereof, and a nozzle located at the end of the third spray pipe and fluidically connected thereto.

[0065] The present invention does not specifically limit the connection method between the spray pipes and between the third spray pipe and the nozzle, and conventional connection methods in the art may be used. For example, a fixed connection or a detachable connection may be used, preferably a threaded connection, or other detachable connection methods are not specifically limited.

[0066] According to one embodiment of the present invention, the spraying liquid is water or an acidic aqueous solution. Preferably, the ammonia-containing gas contacts the acidic aqueous solution serving as the spraying liquid from bottom to top in reverse, with the acidic H+ contained in the aqueous solution reacting with the ammonia to neutralize and remove the ammonia. Here, the acidic aqueous solution is an aqueous solution of an acidic substance. The acidic substance may be an inorganic acid such as hydrochloric acid, sulfuric acid, or phosphoric acid; an organic acid such as acrylic acid or acetic acid; or an acidic salt such as ammonium sulfate, without specific limitations.

[0067] According to the present invention, the droplet size of the spray liquid sprayed from the nozzle is very small, usually only 50-5000 microns, which can effectively play the gas absorption function, especially the ammonia removal function.

[0068] According to one embodiment of the present invention, the projections of all nozzles of the one spraying device and the other spraying device on the cross section substantially overlap. The inventors of the present invention discovered that the multiple spraying devices in the absorption device are both relatively independent individuals and an organic whole. The circulating liquid is transported to the nozzles of each spraying device through the first, second, and third spraying pipes of each spraying device, and a hollow conical liquid surface is formed with the nozzle as the center. The gas and the circulating liquid come into contact in reverse. The gas can only come into contact with the conical liquid surface formed by the upper spraying device after passing through the conical liquid surface formed by the lower spraying device. At the moment the gas passes through the conical liquid surface, the ammonia in the gas and the acid in the liquid undergo a neutralization reaction. As the ammonia-containing gas passes through the multiple hollow conical liquid surfaces of the multiple spraying devices, it is eventually completely neutralized by the acid in the circulating liquid. The area between the hollow conical liquid surfaces of the upper and lower spraying devices can be regarded as a gas rising channel. Since each section is required to have an independent liquid phase circulation spraying device, the rising gas channel has a certain height. The projections of at least one (preferably all) of the first spray pipe, the second spray pipe and the third spray pipe on the cross section basically overlap, that is, the projections of the nozzles (centers of the cones) of each layer on the cross section overlap, so that the ammonia is evenly distributed in the gas channel. If the projections of the upper layer of nozzles and the lower layer of nozzles on the cross section do not overlap, since the hollow cone liquid levels of the upper and lower layers are not in the same position, the gas channel of the rising gas is changed. After the rising gas passes through the gas channel, there is a problem of uneven gas distribution between the gas channels, which reduces the ammonia absorption effect. According to one embodiment of the present invention, the vertical spacing between two adjacent spray devices (measured by the vertical spacing of the spray liquid inlet of the spray device) is 650-1350 mm, preferably 750-1200 mm.

[0069] The inventors discovered that if the cross-sectional projections of the upper and lower nozzles do not overlap, the hollow conical liquid surfaces of the upper and lower layers are located at different positions, altering the path of the rising gas. Some channels become wider, while others become narrower. As the rising gas passes through gas channels at different heights, the varying residence times within the channels can lead to uneven gas distribution. This can lead to ammonia absorption being reduced as the ammonia-containing gas passes through the hollow conical liquid surface, resulting in excess acid in some areas and ammonia penetration in others due to insufficient acid.

[0070] The inventors of the present invention have also discovered that if the cross-sectional projections of the nozzles in the upper and lower layers do not overlap, the spray liquids from the upper and lower layers will collide more frequently. When two droplets collide, they can separate, coalesce, and break apart. The inventors have discovered that when the cross-sectional projections of the nozzles in the upper and lower layers do not overlap, the droplets from the upper and lower layers are more likely to coalesce during collision, forming larger droplets, which is detrimental to ammonia absorption.

[0071] According to one embodiment of the present invention, when the absorption device is cut perpendicularly to its central axis to obtain a cross-section, the projections of at least one (preferably all) of the first, second, and third spray pipes of one of the plurality of spray devices and another of the plurality of spray devices on the cross-section substantially overlap. That is, the projections of the nozzles (cone centers) of each layer on the cross-section overlap, thereby ensuring uniform distribution of ammonia in the gas passage.

[0072] The inventors of the present invention also discovered that as the circulating fluid from each spray device flows along the first spray pipe, the second spray pipe, the third spray pipe, and finally the nozzle, the fluid's pressure continuously decreases due to the resistance of the pipe wall. The pressure at the nozzle distal to the spray liquid inlet is lower than the pressure at the nozzle proximal to the spray liquid inlet. Since the pressure at the farthest nozzle is relatively low, the atomization effect is also relatively poor, resulting in insufficient gas-liquid contact at the farthest nozzle, which easily causes ammonia escape. As the device's operating cycle increases, such as for 18 months or even longer, solid impurities and heavy components with higher viscosity in the pipeline adhere to the pipe wall, further increasing the pipe wall resistance and further weakening the atomization effect at the far nozzle, resulting in more ammonia escape. If the spray liquid inlets of multiple layers of spray devices are on the same side, since the far nozzles of each layer of spray devices are on the same side, the gas-liquid contact in this area is the weakest, making it easier for ammonia in the gas phase to escape from the ammonia absorption tower from this area.

[0073] Based on this discovery, according to one embodiment of the present invention, the angle between the projections of the spray liquid inlet of the one spray device and the other spray device on the cross section is 180°. In the early stage of the operation of the device, since the spray device pipeline is relatively clean, the distal nozzle of the spray device is sufficient to atomize the spray liquid to produce droplets of 50-5000 μm or smaller. After the device has been in continuous operation for 18 months or even longer, although ammonia escapes due to poor gas-liquid contact at the distal nozzle of a spray device due to poor nozzle atomization effect, the escaped ammonia is captured by the spray liquid at the proximal nozzle of the upper layer of the spray device and a neutralization reaction occurs to produce corresponding salts. Usually, multiple layers of spray devices are arranged in the ammonia absorption tower, such as 3 layers, 4 layers, 5 layers or more layers, and the angle between the projections of the spray liquid inlet of the upper (or second) layer of spray devices and the lower (or second) layer of spray devices on the cross section is 180°, which can absorb ammonia to a greater extent, thereby reducing ammonia escape and also reducing acid consumption to a greater extent.

[0074] According to one embodiment of the present invention, the plurality of second spraying pipes extend perpendicularly to the first spraying pipe and substantially in parallel along a horizontal direction toward opposite sides thereof.

[0075] According to one embodiment of the present invention, the plurality of third spraying pipes extend perpendicularly to the second spraying pipe and substantially in parallel along a horizontal direction toward opposite sides thereof.

[0076] According to one embodiment of the present invention, the inner diameter of the first spray pipe is 160-480 mm (preferably 200-450 mm), and the length is 4500-11500 mm (preferably 4800-10500 mm).

[0077] According to one embodiment of the present invention, the plurality of second spray pipes are the same as or different from each other, and each has an independent inner diameter of 30-150 mm (preferably 40-120 mm) and an independent length of 1200-5750 mm (preferably 1800-5250 mm).

[0078] According to one embodiment of the present invention, the plurality of third spray pipes are the same as or different from each other, and each independently has an inner diameter of 10-60 mm (preferably 15-50 mm) and a length of 160-325 mm (preferably 175-300 mm).

[0079] According to one embodiment of the present invention, the nozzles are the same as or different from each other, and the inner diameter (referring to the nozzle outlet) is independently 3-20 mm (preferably 6-14 mm).

[0080] According to one embodiment of the present invention, the spraying angles of the nozzles are independently 65-120° (preferably 70-100° mm).

[0081] According to one embodiment of the present invention, on the first spraying pipe, the horizontal distance between two adjacent second spraying pipes is 640-1300 mm (preferably 700-1200 mm).

[0082] According to one embodiment of the present invention, on the same second spraying pipe, a horizontal distance between two adjacent third spraying pipes is 320-650 mm (preferably 350-600 mm).

[0083] According to one embodiment of the present invention, on two adjacent second spray pipes, the straight-line distance M between the end of any third spray pipe on one second spray pipe and the end of the nearest third spray pipe on the other adjacent second spray pipe (as shown in Figures 6A and 6B) is not less than 320 mm, and preferably not less than 350 mm. The inventors of the present invention have found that in order to improve the absorption efficiency of ammonia, generally, at any position on the cross-section of the tower, there are at least two or more conical liquid surfaces formed with the nozzle as the center overlapping, including the tower wall. If the distance between the ends of the two spray pipes is too large, due to the limitations of the nozzle structure, it is difficult for any position on the tower wall to meet the requirement of overlapping liquid surfaces sprayed by more than two nozzles, thereby increasing the probability of ammonia escaping from the "gap". If the distance between the ends of the two spray pipes is too small, in order to ensure the atomization quality of the spray liquid, the circulating liquid volume in the ammonia absorption tower will inevitably increase, that is, the energy consumption of the pump will increase. 6A and 6B , since the upper and lower multi-layer spraying devices overlap in upper and lower projections, only the upper spraying device and the spraying liquid inlets facing each other can be seen.

[0084] According to one embodiment of the present invention, the nozzles are the same as or different from each other, and the spraying liquid spraying rate of each nozzle is independently 0.5-7.5 t / h (preferably 0.9-6.5 t / h).

[0085] According to one embodiment of the present invention, among all the spray devices, the angle between the projections of the spray liquid inlets of any two odd-numbered spray devices on the cross section is 0°, the angle between the projections of the spray liquid inlets of any two even-numbered spray devices on the cross section is 0°, and the angle between the projections of the spray liquid inlets of any odd-numbered spray device and any even-numbered spray device on the cross section is 180°. The inventors of the present invention have discovered that this arrangement can ensure the most uniform distribution of ammonia in the gas phase in the gas channel.

[0086] According to one embodiment of the present invention, the inner diameter of the absorption device is 4.5-11.5 m (preferably 4.8-10.5 m).

[0087] According to one embodiment of the present invention, projections of all nozzles of the one spraying device and the other spraying device on the cross section substantially coincide with each other.

[0088] According to one embodiment of the present invention, the two nozzles whose projections substantially coincide with each other have the same spray diameter.

[0089] According to one embodiment of the present invention, the vertical spacing between two adjacent spraying devices (measured by the vertical spacing of the spraying liquid inlets of the spraying devices) is 650-1350 mm (preferably 750-1200 mm). The inventors of the present invention have found that when the vertical spacing between two adjacent spraying devices is less than 650 mm, for an ammonia absorption tower with the same number of spraying devices, due to insufficient contact time between the rising ammonia-containing gas and the descending circulating liquid, part of the ammonia in the gas phase directly passes through the hollow conical liquid surface formed by the circulating liquid, resulting in poor ammonia absorption efficiency. Although sufficient gas-liquid contact time can be met by increasing the number of spraying devices to achieve complete absorption of ammonia in the gas phase, the total amount of circulating liquid will increase, and the energy consumption of the pump will increase, which is obviously uneconomical. When the vertical spacing between two adjacent spraying devices is greater than 1350 mm, under the condition of the same spraying device, the height of the tower will increase, that is, the equipment investment cost will increase, and in addition, the difficulty of maintenance will be increased.

[0090] According to one embodiment of the present invention, the nozzle includes a nozzle inlet, a rotation chamber, and a nozzle outlet, wherein the rotation chamber is configured such that the spray liquid entering from the nozzle inlet exits the nozzle outlet in a rotating manner after passing through the rotation chamber. According to the present invention, the rotation chamber can adopt any structure known in the art, as long as the spray liquid exits the nozzle outlet in a rotating manner after passing through the rotation chamber, without particular limitation.

[0091] According to one embodiment of the present invention, the diameters of the rotation chambers are independently 10.0-55.0 mm (preferably 13.0-45.0 mm).

[0092] According to one embodiment of the present invention, two nozzles with substantially overlapping projections have the same spray liquid rotation direction. Because the spray liquids from the two nozzles with overlapping projections collide downward, the droplet states of each nozzle are different. Therefore, relatively speaking, two nozzles with overlapping projections but opposite rotation directions are more likely to break droplets into several small droplets than two nozzles with the same rotation direction. However, droplets that are too small are easily entrained by gas and escape.

[0093] According to one embodiment of the present invention, on at least one (preferably all) of the second spray pipes, two adjacent (preferably all) nozzles located on the same side of the second spray pipe are constructed so that the spray liquid is sprayed in the same rotation direction. Generally, the spray liquid enters the rotating nozzle from the tangential direction of the nozzle, and forms a hollow cone with the nozzle outlet as the vertex after passing through the nozzle outlet. In order to ensure the uniformity of the spray liquid in the tower, the nozzle outlets of the two adjacent nozzles are required to be equidistantly distributed in the cross section of the tower, that is, the spray liquid enters the nozzle in the same tangential direction. Therefore, the spray liquid on the same side of the second spray pipe is sprayed in the same rotation direction, while the spray liquid on opposite sides of the second spray pipe is sprayed in opposite rotation directions. In this way, after the spray liquid sprayed from the nozzles on the same second spray pipe intersects and collides, more droplets remain in their original state and move downward in the original direction of movement.

[0094] According to one embodiment of the present invention, all nozzles on the opposite sides of two adjacent second spray pipes are configured to spray liquid in opposite rotational directions. Here, "adjacent to each other" refers to being on the same side of the first spray pipe and adjacent to each other, while "opposite sides" refers to the sides of one second spray pipe and the other second spray pipe facing each other, as shown in Figure 11C. After the spray liquid ejected from two adjacent nozzles of the adjacent second spray pipes collides during their downward movement, the droplets can maintain their original state and move downward. The droplets are unlikely to aggregate and grow larger, nor are they likely to break into smaller droplets.

[0095] According to one embodiment of the present invention, on at least one (preferably all) of the second spray pipes, at least one (preferably all) nozzles located on one side of the second spray pipe are configured to spray the spray liquid in a rotation direction A, and at least one (preferably all) nozzles located on the other opposite side of the second spray pipe are configured to spray the spray liquid in a rotation direction B, wherein the rotation direction A is opposite to the rotation direction B.

[0096] According to one embodiment of the present invention, the rotation direction A is clockwise, and the rotation direction B is counterclockwise.

[0097] According to one embodiment of the present invention, among all the nozzles of the spraying device, the number of nozzles spraying the spray liquid in the rotation direction A is equal to or substantially equal to the number of nozzles spraying the spray liquid in the rotation direction B. As mentioned above, a prerequisite for uniform spraying is that the nozzles are evenly distributed within the tower, and an axisymmetric distribution is generally preferred. Therefore, the nozzles appear in pairs with axisymmetric rotation directions. If the paired nozzles all rotate in the same direction, it means that all nozzles rotate in the same direction, which can easily cause the spray liquid sprayed from two adjacent nozzles to collide and become larger during the rotation and downward process. Due to the reduction of the total effective contact area with the gaseous ammonia, the ammonia absorption efficiency is reduced.

[0098] According to one embodiment of the present invention, on at least one (preferably all) of the second spray pipes, two adjacent (preferably all) nozzles located on the same side of the second spray pipe are configured so that the spray liquid is sprayed in opposite rotational directions. A third spray pipe is perpendicular to the second spray pipe and extends horizontally parallel to both sides thereof. All nozzles on the same horizontally parallel extension line of the second spray pipe are configured so that the spray liquid is sprayed in the same rotational direction. This is shown in Figure 11E.

[0099] According to one embodiment of the present invention, on at least one (preferably all) of the second spray pipes, one nozzle located in the second spray pipe is configured to spray the spray liquid in a rotational direction A, and at least another nozzle adjacent on one side is configured to spray the spray liquid in a rotational direction B. At least one (preferably all) nozzles located on the opposite other side of the second spray pipe are configured to spray the spray liquid in a rotational direction A, wherein the rotational direction A is opposite to the rotational direction B.

[0100] According to one embodiment, the nozzle includes a nozzle inlet, a nozzle cavity, and a nozzle outlet. The cavity has a special structure that allows the spray liquid entering the nozzle inlet to form droplets after passing through the cavity and exiting the nozzle outlet. As shown in Figure 9, the cavity can adopt any structure known in the art, as long as it can allow the spray liquid to exit the nozzle outlet and form droplets, and there are no specific limitations.

[0101] According to one embodiment, the spray liquid enters the cavity from above the nozzle and forms a solid cone with the nozzle outlet as the vertex after passing through the nozzle outlet. Usually, two adjacent nozzles are equidistantly distributed in the cross section of the tower, and the projections of the nozzles of multiple spraying devices basically overlap. After the spray liquids sprayed from two adjacent nozzles collide in their respective downward processes, the droplets can still maintain their original state and move downward.

[0102] According to one embodiment of the present invention, it also relates to a method for producing a nitrile, in particular a method for producing (meth)acrylonitrile.

[0103] According to one embodiment of the present invention, the manufacture method of described nitrile comprises making hydrocarbon feedstock generation ammoxidation reaction and manufacture the step (being called reactions step) of the reaction product that comprises nitrile and spraying spray liquid to described reaction product with the step (being called cooling step) of cooling described reaction product.At this, in the absorption unit described in aforementioned any embodiment, spray described spray liquid to described reaction product.For this reason, the content that does not describe in detail in this part can directly refer to the relevant content described for absorption unit of preceding text.

[0104] According to one embodiment of the present invention, in the cooling step, the spraying liquid contacts the reaction product in a countercurrent manner.

[0105] According to one embodiment of the present invention, in the cooling step, the flow ratio of the spraying liquid to the reaction product is 15-25:1.

[0106] According to one embodiment of the present invention, in the reaction step, the hydrocarbon feedstock is propylene, the molar ratio of propylene / ammonia / air (as molecular oxygen) is 1:1.1-1.3:1.8-2.0, the reaction temperature is 420-440°C, the reaction pressure (gauge pressure) is 0.03-0.14 MPa, and the catalyst weight hourly space velocity is 0.06-0.15h -1 Alternatively, the hydrocarbon feedstock is isobutylene, the molar ratio of isobutylene / ammonia / air (as molecular oxygen) is 1:1.3-1.6:2.2-2.8, the reaction temperature is 395-420°C, the reaction pressure (gauge pressure) is 0.03-0.14 MPa, and the catalyst weight hourly space velocity is 0.08-0.17 h -1 .

[0107] According to one embodiment of the present invention, depending on the different reaction steps, the composition of the reaction product is generally C 1-4 Nitriles (such as acrylonitrile, etc.) account for about 10-20wt%, C 1-4 The oxygen-containing compound (such as acrolein) accounts for approximately 0.1-5% by weight, O₂ accounts for approximately 0.1-5% by weight, ammonia accounts for approximately 0.1-2% by weight, and other impurities are the remainder, calculated relative to the total weight of the reaction product as 100% by weight. After preliminary cooling, the reaction product generally has a temperature of 195-235°C and a pressure of 0.03-0.14 MPaG. According to the present invention, the aforementioned technical effects of the production method of the present invention are particularly excellent for this specific reaction product.

[0108] According to one embodiment of the present invention, in the cooling step, the spraying liquid cools the temperature of the reaction product from 195-235° C. to 81-86° C. In addition, preferably, the spraying liquid reduces the ammonia content of the reaction product to below 150 ppm.

[0109] A specific embodiment of the present invention is described in detail below by way of example with reference to the accompanying drawings.

[0110] As shown in FIG4B , according to the present invention, reaction gas at a temperature of 225°C and unreacted ammonia enter the ammonia absorber 1 from the ammonia-containing gas feed port 8. Circulating liquid is drawn from the bottom of the tower and delivered to spray devices 3a through 3f via a circulating pump 17. Spray devices 3a, 3c, and 3e are on the same side, while spray devices 3b, 3d, and 3f are on the opposite side. Acidic liquid is added to the circulating pump outlet line from the acid solution port 15. The circulating liquid passes through the spray device 3 and enters from the inlet 18 of the spray device 3. It then flows along the fluid direction through the first spray pipe 19, the second spray pipe 20a (20b), and the third spray pipe 21 to the atomizing nozzle 22. The atomizing nozzle rotates leftward and rightward in a ratio of 1:1. Circulating liquid is sprayed from the nozzle 22 to form an acid mist layer within the ammonia absorber, which absorbs the gaseous ammonia from the gas feed port 8. The tail gas is discharged from the ammonia absorber through the gas phase discharge port 9. The tail gas temperature at the top of the tower is 84°C. The projections of the ends of the third spray pipes of the spraying devices 3a-3f on the cross section of the tower overlap, as shown in Figure 6A. The schematic diagram of the nozzle structure of the spraying device and the top view of the spraying device are shown in Figures 11C and 11B.

[0111] Example

[0112] The present invention is further described in detail below with reference to examples, but the present invention is not limited to these examples.

[0113] Example 1

[0114] The ammonia absorber adopts the two-stage structure shown in Figure 3B , with an inner diameter of 7200 mm. Acid-containing circulating fluid is delivered to the absorber via the upper circulating pump through four spraying devices. The flow in the first spray pipes of spraying devices 3a and 3c, and 3b and 3d, flows in opposite directions, meaning the angle between the projections of adjacent spray liquid inlets is 180°. A top view of the spraying devices is shown in Figure 11B , and a detailed top view of the spraying devices is shown in Figure 11C . The vertical spacing between adjacent spraying devices is 1200 mm. Each spraying device has 16 secondary spray pipes, and each secondary spray pipe is equipped with 11 to 18 tertiary spray pipes. The tertiary spray tips of the spraying devices overlap and rotate in the same direction. All nozzles on the same side of the second spray pipe rotate in the same direction, while nozzles on opposite sides of the second spray pipe rotate in opposite directions. The number of nozzles on the opposite sides of two adjacent second spray pipes with the same rotation direction is 480, and the number of nozzles with the same rotation direction is 480, respectively. The vertical spacing between two adjacent spraying devices is 950 mm. The inner diameter of the first spraying pipe of the spraying device is 250 mm, and the length of the first spraying pipe is 7000 mm. The spacing between the second spraying pipes of the spraying device is 820 mm, the inner diameter of the second spraying pipe is 100 mm, and the length of the second spraying pipe is 2100 mm-3450 mm. The spacing between the third spraying pipes of the spraying device is 410 mm, the inner diameter of the third spraying pipe is 40 mm, and the length of the third spraying pipe is 205 mm. As shown in Figure 6B, the distance between the ends of two adjacent third spraying pipes is 580 mm. The nozzle outlet diameter is 11.5 mm, the nozzle rotation chamber diameter is 40 mm, and the nozzle spray angle is 75 degrees. The vertical distance from the gas feed port 8 to the spraying device 3d is 4000 mm, and the inner diameter of the feed port is 1300 mm. The reaction product gas entering through the feed port contained approximately 0.71 wt% ammonia, 13.2 wt% acrylonitrile, and the remainder impurities such as O₂, acrolein, and nitrogen. Its temperature was 225°C and its pressure was 0.06 MPaG. Each nozzle discharged 4.8 t / h of spray liquid, and the weight ratio of spray liquid to reaction product gas entering through the gas inlet was 20. After one month of operation, the residual ammonia concentration in the exhaust gas at the reaction outlet was 39 ppm. After 24 months of operation, the residual ammonia concentration in the exhaust gas at the reaction outlet was 41 ppm. The acid consumption for 24 months of operation was divided by the acid consumption for one month of operation by 1.02.

[0115] Example 2

[0116] The ammonia absorber adopts the one-stage structure shown in Figure 4B , with an inner diameter of 7200 mm. Acid-containing circulating fluid is delivered to the absorber via a circulating pump through six spraying devices. The flow in the first spray pipes of spraying devices 3a, 3c, and 3e is in opposite directions from that of 3b, 3d, and 3f, meaning that the angle between the projections of adjacent spray inlets is 180°. A top view of the spraying devices is shown in Figure 11B , and a detailed top view of the spraying devices is shown in Figure 11C . The vertical spacing between adjacent spraying devices is 880 mm. Each spraying device has 14 secondary spray pipes, and each secondary spray pipe is equipped with 6 to 14 tertiary spray pipes. The tertiary spray tips of the spraying devices overlap and rotate in the same direction. All nozzles on the same side of the second spray pipe rotate in the same direction, while nozzles on opposite sides of the second spray pipe rotate in opposite directions. The number of nozzles on the opposite sides of two adjacent second spray pipes with the same rotation direction is 456 and 456, respectively. The vertical spacing between two adjacent spraying devices is 920 mm. The first spraying pipe of the spraying device has an inner diameter of 200 mm and a length of 7000 mm. The second spraying pipes of the spraying device are spaced 1000 mm apart, have an inner diameter of 100 mm, and have a length ranging from 1850 mm to 3450 mm. The third spraying pipes of the spraying device are spaced 500 mm apart, have an inner diameter of 40 mm, and are 250 mm long. The projections of the third spraying ends of the spraying devices overlap, and the distance between the ends of two adjacent third spraying pipes is 707 mm, as shown in Figure 6B. The nozzle outlet diameter is 11.7 mm, the nozzle rotation chamber diameter is 44 mm, and the spray angle is 80°. The vertical distance from the gas feed port 8 to the spraying device 3d is 4000 mm, and the feed port inner diameter is 1300 mm. The reaction product gas entering through the feed port contained approximately 0.71 wt% ammonia, 13.2 wt% acrylonitrile, and the remainder impurities such as O₂, acrolein, and nitrogen. Its temperature was 225°C and its pressure was 0.06 MPaG. Each nozzle discharged 5.1 t / h of spray liquid, and the weight ratio of spray liquid to reaction product gas entering through the gas inlet was 20. After one month of operation, the residual ammonia concentration in the exhaust gas at the reaction outlet was 34 ppm. After 24 months of operation, the residual ammonia concentration in the exhaust gas at the reaction outlet was 37 ppm. The acid consumption for 24 months of operation was divided by the acid consumption for one month of operation by 1.01.

[0117] Example 3

[0118] The ammonia absorption tower was identical to Example 2, except that it employed the one-stage structure shown in FIG4A . The flow directions within the first spray pipes of spray devices 3a, 3b, and 3c were opposite to those of spray devices 3d, 3e, and 3f. This meant that the projections of the spray inlets of the upper three layers of spray devices 3a, 3b, and 3c substantially overlapped, as did the projections of the spray inlets of the lower three layers of spray devices 3d, 3e, and 3f. Furthermore, the angle between the projections of the spray inlets of the upper and lower three layers was 180°. After one month of operation, the residual ammonia concentration in the exhaust gas from the reaction outlet was 42 ppm. After 24 months of operation, the residual ammonia concentration in the exhaust gas from the reaction outlet was 61 ppm. The acid consumption for 24 months of operation was divided by the acid consumption for one month of operation by 1.03.

[0119] Example 4

[0120] The same as Example 2, the only difference is that the projections of the first spray pipes of the spray devices 3a, 3c, 3e and 3b, 3d, 3f on the cross section overlap, while the projections of the second spray pipe, the third spray pipe and the nozzle on the cross section do not overlap. As shown in FIG7A , after the device has been in operation for 1 month, the residual ammonia concentration of the exhaust gas at the reaction outlet is 78 ppm, and after the device has been in operation for 24 months, the residual ammonia concentration of the exhaust gas at the reaction outlet is 95 ppm. The acid consumption of the device in 24 months of operation / the acid consumption of the device in 1 month of operation is 1.05.

[0121] Example 5

[0122] The same as Example 2, except that the nozzle rotation chambers on opposite sides of the seven second spray pipes on each spray device were oriented in opposite directions, while the nozzle rotation chambers on opposite sides of the other seven second spray pipes were oriented in the same direction. After the device operated for one month, the residual ammonia concentration in the exhaust gas at the reaction outlet was 90 ppm. After the device operated for 24 months, the residual ammonia concentration in the exhaust gas at the reaction outlet was 105 ppm. The acid consumption for the 24-month operation of the device / the acid consumption for the one-month operation of the device was 1.04.

[0123] Example 6

[0124] The same as Example 2, the only difference is that the projections of the third spraying ends of the spraying devices overlap and the rotation directions of the nozzles of adjacent spraying devices with overlapping projections are opposite. After the device has been in operation for 1 month, the residual ammonia concentration of the exhaust gas at the reaction outlet is 85 ppm. After the device has been in operation for 24 months, the residual ammonia concentration of the exhaust gas at the reaction outlet is 110 ppm. The acid consumption of the device in 24 months of operation / the acid consumption of the device in 1 month of operation is 1.05.

[0125] Example 7

[0126] The same as Example 2, except that the two adjacent nozzles on one side of the second spray pipe of the spray device rotate in opposite directions, while all nozzles on the same horizontal parallel extension line of the second spray pipe rotate in the same direction. A top view of the spray device is shown in Figure 11B, and a detailed top view of the spray device is shown in the schematic diagram of Figure 11E. After one month of operation, the residual ammonia concentration in the reaction outlet exhaust gas was 106 ppm. After 24 months of operation, the residual ammonia concentration in the reaction outlet exhaust gas was 125 ppm. The acid consumption of the device in 24 months of operation / the acid consumption of the device in one month of operation was 1.05.

[0127] Example 8

[0128] The same as in Example 2, except that all nozzles on opposite sides of two adjacent second spray pipes of the spraying device sprayed liquid in the same direction of rotation, while the nozzles on both sides of the same second spray pipe sprayed liquid in opposite directions of rotation. After the device operated for one month, the residual ammonia concentration in the exhaust gas at the reaction outlet was 108 ppm. After the device operated for 24 months, the residual ammonia concentration in the exhaust gas at the reaction outlet was 121 ppm. The acid consumption of the device in 24 months of operation / the acid consumption of the device in one month of operation was 1.04.

[0129] Example 9

[0130] The same as Example 2, except that only two adjacent nozzles on one side of the second spray pipe of the spray device rotated in the same direction, while the other two adjacent nozzles rotated in opposite directions, and the nozzles on opposite sides of the same second spray pipe rotated in opposite directions. After the device operated for one month, the residual ammonia concentration in the exhaust gas at the reaction outlet was 125 ppm. After the device operated for 24 months, the residual ammonia concentration in the exhaust gas at the reaction outlet was 148 ppm. The acid consumption of the device in 24 months of operation / the acid consumption of the device in one month of operation was 1.05.

[0131] Example 10

[0132] The same as Example 1, except that the rotation chamber directions of all nozzles of the spraying device are all the same, the device is operated for 1 month, the residual ammonia concentration of the tail gas from the reaction outlet is 129 ppm, the device is operated for 24 months, the residual ammonia concentration of the tail gas from the reaction outlet is 149 ppm, and the acid consumption of the device in 24 months of operation / the acid consumption of the device in 1 month of operation is 1.06.

[0133] Example 11

[0134] The same as Example 2, except that the distance between adjacent third spray pipes is 300 mm, and the distance between the ends of two adjacent third spray pipes (as shown in Figure 6A) is 300 mm. The residual ammonia concentration in the tail gas at the reactor outlet is 76 ppm.

[0135] Example 12

[0136] The same as Example 2, except that the distance between the ends of two adjacent third spray pipes is 340 mm as shown in FIG6A . The residual ammonia concentration of the tail gas at the reaction outlet is 105 ppm.

[0137] Example 13

[0138] The same as Example 2, except that the vertical spacing between two adjacent spraying devices is 1500 mm, and the spacing between the third spraying pipes of the spraying device is 500 mm; after the device has been in operation for 1 month, the residual ammonia concentration in the tail gas from the reaction outlet is 117 ppm, and the residual ammonia concentration in the tail gas from the reaction outlet is 139 ppm after the device has been in operation for 24 months. The acid consumption of the device in 24 months of operation / the acid consumption of the device in 1 month of operation is 1.05.

[0139] Example 14

[0140] The same as Example 2, except that the vertical spacing between two adjacent spraying devices is 700 mm, and the spacing between the third spraying pipes of the spraying device is 500 mm; after the device has been in operation for 1 month, the residual ammonia concentration in the tail gas from the reaction outlet is 75 ppm, and the device has been in operation for 24 months, the residual ammonia concentration in the tail gas from the reaction outlet is 97 ppm, and the acid consumption of the device in 24 months of operation / the acid consumption of the device in 1 month of operation is 1.07.

[0141] Example 15

[0142] The same as Example 2, except that the vertical spacing between two adjacent spraying devices is 1300 mm, and the spacing between the third spraying pipes of the spraying device is 500 mm; after the device has been in operation for 1 month, the residual ammonia concentration in the tail gas from the reaction outlet is 108 ppm, and the device has been in operation for 24 months, the residual ammonia concentration in the tail gas from the reaction outlet is 121 ppm, and the acid consumption of the device in 24 months of operation / the acid consumption of the device in 1 month of operation is 1.04.

[0143] Example 16

[0144] The same as Example 2, except that the vertical spacing between two adjacent spraying devices is 550 mm, the device is operated for 1 month, the residual ammonia concentration of the reaction outlet exhaust gas is 129 ppm, the device is operated for 24 months, the residual ammonia concentration of the reaction outlet exhaust gas is 145 ppm, and the acid consumption of the device in 24 months of operation / the acid consumption of the device in 1 month of operation is 1.04.

[0145] Example 17

[0146] The same as Example 2, except that the spray liquid discharge rate of each nozzle is 8.9 t / h, and the weight ratio of the spray liquid to the reaction product gas entering from the gas inlet is 35; after the device has been in operation for 1 month, the residual ammonia concentration in the tail gas at the reaction outlet is 85 ppm, and after the device has been in operation for 24 months, the residual ammonia concentration in the tail gas at the reaction outlet is 99 ppm, and the acid consumption of the device in 24 months of operation / the acid consumption of the device in 1 month of operation is 1.03.

[0147] Example 18

[0148] The same as Example 2, except that the spray liquid discharge rate of each nozzle is 1.6 t / h, and the weight ratio of the spray liquid to the reaction product gas entering from the gas inlet is 8; after the device has been in operation for 1 month, the residual ammonia concentration in the tail gas at the reaction outlet is 135 ppm, and after the device has been in operation for 24 months, the residual ammonia concentration in the tail gas at the reaction outlet is 169 ppm, and the acid consumption of the device in 24 months of operation / the acid consumption of the device in 1 month of operation is 1.05.

[0149] Example 19

[0150] The same as Example 2, except that the nozzle outlet diameter on the 1st to 11th second spray pipes of the first spray pipe along the fluid direction is 11.7 mm, and the nozzle outlet diameter on the 12th to 14th second spray pipes of the first spray pipe is 11.9 mm; after the device has been in operation for 1 month, the residual ammonia concentration in the tail gas at the reaction outlet is 85 ppm, and after the device has been in operation for 24 months, the residual ammonia concentration in the tail gas at the reaction outlet is 99 ppm, and the acid consumption of the device in 24 months of operation / the acid consumption of the device in 1 month of operation is 1.03.

[0151] Example 20

[0152] The same method as in Example 2 differed only in that the projections of the first and second spray pipes of spray devices 3a, 3b, and 3c overlapped with those of 3d, 3e, and 3f, while the projections of the third spray pipes did not overlap, as shown in FIG7B . After one month of operation, the residual ammonia concentration in the exhaust gas at the reaction outlet was 64 ppm. After 24 months of operation, the residual ammonia concentration in the exhaust gas at the reaction outlet was 82 ppm. The acid consumption for 24 months of operation / one month of operation was 1.04.

[0153] Example 21

[0154] The same as Example 2, except that the rotation chambers of the 10 adjacent nozzles on the same side of the second spray pipes in each spray device rotate in the same direction, the adjacent nozzles on the same side of the other 4 second spray pipes rotate in opposite directions, and the nozzles on opposite sides of the second spray pipes of the spray device rotate in opposite directions. After the device operated for one month, the residual ammonia concentration in the exhaust gas at the reaction outlet was 81 ppm. After the device operated for 24 months, the residual ammonia concentration in the exhaust gas at the reaction outlet was 105 ppm. The acid consumption of the device in 24 months of operation / the acid consumption of the device in one month of operation was 1.03.

[0155] Example 22

[0156] The same as Example 2, except that the two adjacent nozzles on the same side of the four second spray pipes on each spray device rotate in the same direction, the two adjacent nozzles on the same side of the other ten second spray pipes rotate in opposite directions, and the nozzles on opposite sides of the second spray pipes of the spray device rotate in opposite directions. After the device operated for one month, the residual ammonia concentration in the exhaust gas at the reaction outlet was 108 ppm. After the device operated for 24 months, the residual ammonia concentration in the exhaust gas at the reaction outlet was 125 ppm. The acid consumption of the device in 24 months of operation / the acid consumption of the device in one month of operation was 1.04.

[0157] Comparative Example 1

[0158] The same as Example 1, the only difference is that the spray inlets 18 of spray devices 3a, 3c and 3b, 3d are on the same side of the ammonia absorber, that is, the flow direction in the first spray pipe is the same, the spray inlet projections of spray devices 3a, 3b, 3c and 3d basically overlap, (as shown in Figure 1), and the cross-sectional projections of the nozzles at the end of the third spray pipes of spray devices 3a, 3c and 3b, 3d overlap (as shown in Figure 5). After the device operated for one month, the residual ammonia concentration in the reaction outlet exhaust gas was 85 ppm. After the device operated for 24 months, the residual ammonia concentration in the reaction outlet exhaust gas was 253 ppm. The acid consumption of the device in 24 months of operation / the acid consumption of the device in one month of operation was 1.13.

[0159] Comparative Example 2

[0160] The same as Example 2, the only difference is that the spray inlets 18 of spray devices 3a, 3c, 3e and 3b, 3d, 3f are on the same side of the ammonia absorber, that is, the flow direction in the first spray pipe is the same, the spray inlet projections of spray devices 3a, 3b, 3c, 3d, 3e, 3f basically overlap, (as shown in Figure 2), and the cross-sectional projections of the nozzles at the end of the third spray pipes of spray devices 3a, 3c and 3b, 3d overlap (as shown in Figure 5). After the device was operated for one month, the residual ammonia concentration in the reaction outlet exhaust gas was 73ppm. After the device was operated for 24 months, the residual ammonia concentration in the reaction outlet exhaust gas was 223ppm. The acid consumption of the device in 24 months of operation / the acid consumption of the device in one month of operation was 1.13.

[0161] Comparative Example 3

[0162] This is the same as Example 2, differing only in that the spray inlets 18 of spray devices 3a, 3c, and 3e, and 3b, 3d, and 3f, project at a 30° angle on the cross section. That is, the flow directions of the corresponding first spray pipes of the spray devices are oriented at a 30° angle, and the projections of the ends of the third spray pipes of the spray devices do not overlap, as shown in FIG8B . After one month of operation, the residual ammonia concentration in the exhaust gas at the reaction outlet was 130 ppm. After 24 months of operation, the residual ammonia concentration in the exhaust gas at the reaction outlet was 343 ppm. The acid consumption for 24 months of operation / one month of operation was 1.15.

[0163] Comparative Example 4

[0164] This is the same as Example 2, except that the spray inlets 18 of spray devices 3a, 3c, and 3e, and 3b, 3d, and 3f, project at a 90° angle on the cross section. That is, the flow directions of the corresponding first spray pipes of the spray devices are 90°, and the projections of the ends of the third spray pipes of the spray devices do not overlap. After one month of operation, the residual ammonia concentration in the exhaust gas at the reaction outlet was 110 ppm. After 24 months of operation, the residual ammonia concentration in the exhaust gas at the reaction outlet was 293 ppm. The acid consumption for 24 months of operation / one month of operation was 1.10.

[0165] Comparative Example 5

[0166] This is the same as Example 2, differing only in that the spray inlets 18 of spray devices 3a, 3c, and 3e, and 3b, 3d, and 3f, project at a 120° angle on the cross-section. This means that the flow directions of the corresponding first spray pipes of the spray devices are 90°, and the projections of the ends of the third spray pipes of the spray devices do not overlap, as shown in Figure 8B. After one month of operation, the residual ammonia concentration in the exhaust gas at the reaction outlet was 132 ppm. After 24 months of operation, the residual ammonia concentration in the exhaust gas at the reaction outlet was 353 ppm. The acid consumption for 24 months of operation / one month of operation was 1.15.

Claims

1. An absorption device, comprising a shell and a plurality of spray devices arranged in layers at predetermined vertical intervals along the central axis direction of the absorption device, wherein each of the spray devices independently comprises a spray liquid inlet, a first spray pipe in fluid communication with the spray liquid inlet, a plurality of second spray pipes in fluid communication with the first spray pipe and extending perpendicularly to the first spray pipe to both sides thereof, a plurality of third spray pipes in fluid communication with the second spray pipe and extending perpendicularly to the second spray pipe to both sides thereof, and a nozzle located at the end of the third spray pipe and in fluid communication with the third spray pipe, wherein when the absorption device is cross-sectioned perpendicularly to the central axis direction of the absorption device to obtain a cross section, the projections of at least one (preferably all) of the first spray pipe, the second spray pipe and the third spray pipe of one of the plurality of spray devices and another of the plurality of spray devices on the cross section substantially coincide, and the angle between the projections of the spray liquid inlets of the one spray device and the other spray device on the cross section is 180°.

2. The absorption device according to claim 1, wherein on the first spray pipe, the horizontal spacing between two adjacent second spray pipes is 640-1300 mm (preferably 700-1200 mm), and / or, on the same second spray pipe, the horizontal spacing between two adjacent third spray pipes is 320-650 mm (preferably 350-600 mm), and / or, on two adjacent second spray pipes, the straight-line distance M between the end of any third spray pipe on one second spray pipe and the end of any third spray pipe on another adjacent second spray pipe is not less than 320 mm (preferably not less than 350 mm).

3. The absorption device according to claim 1, wherein the nozzles are the same or different from each other, and the spraying amount of the spraying liquid is independently 0.5-7.5 t / h (preferably 0.9-6.5 t / h).

4. The absorption device according to claim 1, wherein among all the spray devices, the angle between the projections of the spray liquid inlets of any two odd-numbered spray devices on the cross section is 0°, the angle between the projections of the spray liquid inlets of any two even-numbered spray devices on the cross section is 0°, and the angle between the projections of the spray liquid inlets of any odd-numbered spray device and any even-numbered spray device on the cross section is 180°.

5. The absorption device according to claim 1, wherein the projections of all nozzles of the one spraying device and the other spraying device on the cross section substantially overlap, and / or the two nozzles whose projections substantially overlap have the same spray diameter.

6. The absorption device of claim 1, wherein the nozzle comprises a nozzle inlet, a rotation chamber, and a nozzle outlet, wherein the rotation chamber is configured such that the spray liquid entering from the nozzle inlet leaves the nozzle outlet in a rotating manner after passing through the rotation chamber.

7. The absorption device according to claim 6, wherein the diameters of the rotating chambers are independently 10.0-55.0 mm (preferably 13.0-45.0 mm), and / or the two nozzles whose projections substantially overlap have the same spray liquid rotation direction.

8. The absorption device according to claim 1, wherein on at least one (preferably all) of the second spray pipes, two adjacent (preferably all) nozzles located on the same side of the second spray pipe are configured so that the spray liquid is sprayed in the same rotation direction.

9. The absorption device according to claim 8, wherein all nozzles on opposite sides of two of the second spray pipes adjacent to each other are constructed so that the spray liquid is sprayed in opposite rotation directions.

10. The absorption device according to claim 8, wherein on at least one (preferably all) of the second spray pipes, at least one (preferably all) nozzles located on one side of the second spray pipe are constructed so that the spray liquid is sprayed in a rotation direction A, and at least one (preferably all) nozzles located on the other side of the second spray pipe are constructed so that the spray liquid is sprayed in a rotation direction B, wherein the rotation direction A is opposite to the rotation direction B.

11. The absorption device according to claim 10, wherein among all the nozzles of the spraying device, the number of nozzles spraying the spray liquid in the rotation direction A is equal to or substantially equal to the number of nozzles spraying the spray liquid in the rotation direction B.

12. The absorption device according to claim 1, wherein the vertical distance between two adjacent spraying devices (measured by the vertical distance between the spraying liquid inlets of the spraying devices) is 650-1350 mm (preferably 750-1200 mm).

13. A method for producing nitrile, comprising a step of subjecting a hydrocarbon raw material to an ammoxidation reaction to produce a reaction product containing nitrile (referred to as a reaction step), and a step of spraying a spray liquid onto the reaction product to cool the reaction product (referred to as a cooling step), wherein the spray liquid is sprayed onto the reaction product in the absorption device described in claim 1.

14. The manufacturing method according to claim 13, wherein in the cooling step, the flow ratio of the spraying liquid to the reaction product is 15-25:1.

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