Absorbing device having a spray liquid inlet on the opposite side and method for producing nitrile

Abstract

The present invention relates to an absorbent apparatus and a nitrile manufacturing process having opposing spray inlets. This absorbent apparatus can maximize ammonia absorption and reduce ammonia breakthrough. The absorbent apparatus of the present invention comprises a housing and a plurality of sprayers arranged in layers at predetermined vertical intervals along the central axis of the absorbent apparatus. Each sprayer independently comprises a spray inlet, a first spray pipe that is in fluid communication with the spray inlet, a plurality of second spray pipes that are in fluid communication with the first spray pipe and are arranged perpendicularly to the first spray pipe along both sides thereof, a plurality of third spray pipes that are arranged perpendicularly to the second spray pipe along both sides thereof, and a nozzle located at the end of the third spray pipe and in fluid communication with it. Here, in a cross-section obtained by cutting the absorption device in a direction perpendicular to the central axis of the absorption device, at least one is selected from the first spray tube, second spray tube, and third spray tube of one of the plurality of spray devices, and at least one selected from the group consisting of the first spray tube, second spray tube, and third spray tube substantially coincides in the projection on the cross-section, and the angle made in the cross-section by the projection of the spray liquid inlet of one spray device and the spray liquid inlet of the other spray device is 180°.

Description

Detailed Description of the Invention

[0001] 〔Technical Field〕 The present invention relates to the technical field of gas absorption, and more specifically, to an absorption device having a spray liquid inlet arranged on the opposite side and a method for producing nitrile. 〔Background〕

[0002] In the process route for producing the corresponding nitrile by ammoniation or ammoxidation, in order to maximize the conversion rate of the raw material gas such as hydrocarbon, ammonia, which is the raw material gas, is usually used in an excessive amount. That is, the molar ratio of ammonia to the hydrocarbon raw material gas is greater than 1. For example, in the ammoxidation of propylene, the ammonia ratio (molar ratio of ammonia to propylene) is 1.10 - 1.35, and in the ammoxidation of aromatic hydrocarbons, the ammonia ratio (molar ratio of ammonia to aromatic hydrocarbons) is 4 - 8. Therefore, the exhaust gas (tail gas) at the reactor outlet necessarily contains unreacted ammonia. On the other hand, in the acrylonitrile production process etc., reaction gases such as acrylonitrile are likely to polymerize under alkaline conditions. On the other hand, the dissipation of a very small amount of unreacted ammonia easily causes environmental pollution. Therefore, in the ammoniation or ammoxidation process, it is desirable to remove unreacted ammonia from the gas phase using an absorption device (generally called an ammonia absorption tower or a quench tower) with an acid or water, and this process is very necessary.

[0003] With the development of production technology, the production load is continuously increasing, and the trend of equipment enlargement indicates the future development direction. The higher the equipment load, the larger the equipment including the absorption device. In the absorption device, it is known that the circulating liquid (spray liquid) is distributed into the absorption device through a spraying device and contacts the ammonia-containing gas to be absorbed in countercurrent to achieve the purpose of removing residual ammonia from the gas phase.

[0004] CN105425849 teaches that residual ammonia can be removed by adjusting the amount of acid added based on the pH value of the wastewater from the absorber. CN1199940 teaches that mass transfer and heat transfer effects between the gas and liquid phases can be improved by adding internal components to the bottom of the absorber, which in practice solves the problem of uniform distribution of the ammonia-containing gas phase. However, the absorber still cannot avoid ammonia breakthrough, meaning that small amounts of ammonia dissipation still exist, causing product loss or environmental pollution in subsequent purification and separation equipment.

[0005] In conventional ammonia absorption methods, the ammonia content in the absorbed exhaust gas increases significantly after the absorption device has been operated for a long period of time compared to the initial stage of operation. [Summary of the Invention]

[0006] The inventors of this invention have found that, because the spray liquid inlets of existing devices are usually located on the same side, after long operating cycles, solid impurities or other viscous heavy components, and other easily deposited substances accumulate in the circulating spray liquid, adhering to the inner walls of the spray piping and nozzles of the spray device. This continuously increases the fluid flow resistance, resulting in insufficient nozzle pressure and a reduction in the atomization effect of the spray. The further away from the spray liquid inlet, the more serious the accumulation problem becomes. After long-term operation, the degree of accumulation differs at different locations in the spray device, resulting in differences in the degree of atomization of the spray liquid from different nozzles. In areas where atomization is insufficient, ammonia dissipation becomes significant.

[0007] The inventors of this invention analyzed the degree of accumulation of substances prone to depositing in various parts of a spraying device during continuous operation cycles and their impact on the spraying effect. As a result of comprehensively considering the complementarity between regions of different spraying degrees (different degrees of degradation) in different spraying devices, they discovered that by arranging multiple layers of spraying devices, overlapping the vertical projections of different spraying devices, and arranging the spray liquid inlets to face each other, regions of different spraying degrees correspond to and complement each other, thereby achieving a uniform spraying degree overall.

[0008] The inventors of this invention also discovered that, in the prior art, since the spray liquids are sprayed in the same rotational direction, droplets formed by one spray liquid come into contact with droplets formed by another spray liquid as the spray liquid descends, increasing the droplet size. This reduces the effective area of ​​gas-liquid contact, leading to a decrease in the efficiency of acid utilization and, at the same time, an increase in ammonia escape.

[0009] The inventors of the present invention have discovered that this problem can be solved by positioning the spray liquid inlet of one spraying device horizontally opposite the spray liquid inlet of the other spraying device, and more preferably by controlling the rotational spray direction of the spray liquid from, for example, two adjacent nozzles. The present invention is completed based on this discovery.

[0010] Specifically, the present invention relates to the following points. 1. An absorption device comprising a housing and a plurality of (e.g., 2 to 10, preferably 4 to 8) spray devices arranged in layers at predetermined vertical intervals along the central axis of the absorption device, wherein each spray device independently comprises a spray liquid inlet, a first spray pipe communicating fluidly with the spray liquid inlet, a plurality of (e.g., 10 to 26, preferably 12 to 22) second spray pipes communicating fluidly with the first spray pipe, and a plurality of (e.g., 4 to 26, preferably 6 to 22) third spray pipes communicating fluidly with the first spray pipe and arranged perpendicularly to the first spray pipe along both sides thereof, which communicate fluidly with the second spray pipe and are arranged perpendicularly to the second spray pipe along both sides thereof. Furthermore, a nozzle located at the end of the third spray pipe and communicating fluidly with it is provided. In a cross-section obtained by cutting perpendicular to the central axis of the absorption device, at least one (preferably all) selected from the first, second, and third spray tubes in one of the plurality of spray devices, at least one (preferably all) selected from the first, second, and third spray tubes in another spray device, and at least one (preferably all) selected from the third spray tube, substantially coincide in their cross-sectional projection, and the angle between the projection of the spray liquid inlet of one spray device and the projection of the spray liquid inlet of another spray device is 180° in the cross-section.

[0011] 2. In any of the preceding or following paragraphs of the absorption apparatus, the plurality of second spray tubes extend substantially parallel to the horizontal direction perpendicular to the first spray tube and in two opposite directions. The plurality of third spray tubes extend substantially parallel to the horizontal direction perpendicular to the second spray tube and in two opposite directions.

[0012] 3. In the absorption device described in either the preceding or following paragraph, the inner diameter of the first spray tube is 160 to 480 mm (preferably 200 to 450 mm), and its length is 4500 to 11500 mm (preferably 4800 to 10500 mm). The multiple second spray tubes are identical or different from each other, and each independently has an inner diameter of 30 to 150 mm (preferably 40 to 120 mm) and a length of 1200 to 5750 mm (preferably 1800 to 5250 mm). The multiple third spray tubes are identical or different from each other, and each independently has an inner diameter of 10 to 60 mm (preferably 15 to 50 mm) and a length of 160 to 325 mm (preferably 175 to 300 mm).

[0013] 4. In the absorption device described in either the preceding or following paragraph, the nozzles are identical or different from each other, and each nozzle independently has an inner diameter (see nozzle outlet) of 3 to 20 mm (preferably 6 to 14 mm) and a spray angle of 65 to 120° (preferably 70 to 100°).

[0014] 5. In an absorption device based on any of the above points, on the first spray pipe, the horizontal distance between two adjacent second spray pipes is 640 to 1300 mm (preferably 700 to 1200 mm), and / or, on the same second spray pipe, the horizontal distance between two adjacent third spray pipes is 320 to 650 mm (preferably 350 to 600 mm). Also, on the same second spray pipe, the horizontal distance between two adjacent third spray pipes is 320 to 650 mm (preferably 350 to 600 mm). Furthermore, between two adjacent second spray pipes, the straight-line distance M between any end of a third spray pipe on one second spray pipe and any end of a third spray pipe on the other adjacent second spray pipe is 320 mm or more (preferably 350 mm or more).

[0015] 6. In the absorption device according to any of the preceding or following items, the nozzles may be the same or different from each other, and each nozzle independently has a spray liquid discharge rate of 0.5 to 7.5 t / h (preferably 0.9 to 6.5 t / h).

[0016] 7. In an absorption device having either of the features described above or below, the angle between the cross-sectional projections of the spray liquid inlet of any two odd-numbered spray devices is 0°. The angle between the cross-sectional projections of the spray liquid inlet of any even-numbered spray device is 0°, and the angle between the cross-sectional projection of the spray liquid inlet of any odd-numbered spray device and the cross-sectional projection of the spray liquid inlet of any even-numbered spray device is 180°.

[0017] 8. An absorption device according to either the above or below description, wherein the inner diameter of the absorption device is 4.5 to 11.5 m (preferably 4.8 to 10.5 m).

[0018] 9. An absorption device according to any of the preceding or following paragraphs, characterized in that all nozzles of one spraying device and the other spraying device substantially coincide in cross-sectional projection, and / or two nozzles having substantially coincident projections have the same spray diameter.

[0019] 10. An absorption device according to either the preceding or following embodiment, wherein the nozzle comprises a nozzle inlet, a rotating chamber, and a nozzle outlet, and the rotating chamber is configured such that the spray liquid supplied from the nozzle inlet passes through the rotating chamber and is then discharged from the nozzle outlet while rotating.

[0020] 11. In an absorption device having either of the features described above or below, each rotating chamber independently has a diameter of 10.0 to 55.0 mm (preferably 13.0 to 45.0 mm), and / or two nozzles having substantially coincident projections have the same direction of rotation of the spray liquid.

[0021] 12. In the absorption device having any one of the foregoing or following features, in 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 such that the spray liquid is sprayed in the same rotation direction.

[0022] 13. In the absorption device according to any one of the foregoing or following aspects, all nozzles facing each other on the opposite sides of two adjacent second spray pipes are configured such that the spray liquid is sprayed in the opposite rotation directions.

[0023] 14. In the absorption device according to any one of the foregoing features or the following features, in at least one (preferably all) of the second spray pipes, at least one (preferably all) nozzle arranged on one side of the second spray pipe is configured such that the spray liquid is sprayed in the rotation direction A. On the other hand, at least one (preferably all) nozzle arranged on the opposite side of the second spray pipe is configured such that the spray liquid is sprayed in the rotation direction B. Here, the rotation direction A is opposite to the rotation direction B.

[0024] 15. In the absorption device according to any one of the foregoing or following aspects, the rotation direction A is clockwise and the rotation direction B is counterclockwise.

[0025] 16. An absorption device according to any one of the foregoing or following aspects, among all 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.

[0026] 17. An absorption device according to any one of the foregoing or following aspects, the vertical interval between two adjacent spraying devices (calculated as the vertical interval of the spray liquid inlets of the spraying devices) is 650 - 1350 mm (preferably 750 - 1200 mm).

[0027] 18. A process 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 the reaction step), and a step of spraying a spray liquid onto the reaction product to cool the reaction product (referred to as the cooling step), wherein the spray liquid is sprayed onto the reaction product in the absorption device described in any of the preceding or following items.

[0028] 19. In any of the methods of the preceding or following items, in the cooling step, the spray liquid and the reaction product are brought into contact in a countercurrent manner.

[0029] 20. In the method described in any of the preceding or following items, in the cooling step, the flow rate ratio of the spray liquid to the reaction product is 15 - 25:1.

[0030] 21. In a process according to any of the preceding or following aspects, in the reaction step, the hydrocarbon raw material is propylene, and the molar ratio of propylene / ammonia / air (calculated as molecular oxygen) is 1:1.1 - 1.3:1.8 - 2.0, and the reaction is carried out at a reaction temperature of 420 - 440°C, a reaction pressure (gauge pressure) of 0.03 - 0.14 MPa, and a catalyst weight hourly space velocity of 0.06 - 0.15 h -1 Alternatively, the hydrocarbon raw material is isobutylene, and the molar ratio of isobutylene / ammonia / air (calculated as molecular oxygen) is 1:1.3 - 1.6:2.2 - 2.8, and the reaction is carried out at a reaction temperature of 395 - 420°C, a reaction pressure (gauge pressure) of 0.03 - 0.14 MPa, and a catalyst weight hourly space velocity of 0.08 - 0.17 h -1 is carried out.

[0031] 22. In a process according to any of the preceding or following aspects, in the cooling step, the spray liquid cools the temperature of the reaction product from 195 - 235°C to 81 - 86°C, and / or in the cooling step, the spray liquid reduces the ammonia content of the reaction product to 150 ppm or less.

[0032] 〔Technical effects〕 According to the present invention, even after long-term operation (for example, continuous operation for 18 months or more), the ammonia content in the absorbed exhaust gas does not increase significantly compared to the initial stage of operation, allowing for the maintenance of a good ammonia absorption effect over a long period and reducing ammonia dissipation.

[0033] According to the present invention, even after long-term operation (for example, after 18 months or more of continuous operation), the total acid consumption remains at a low level and increases only slightly (for example, less than 3%).

[0034] According to the present invention, sufficient gas-liquid contact is achieved, the ammonia absorption effect is excellent, and the amount of acid used can be reduced.

[0035] According to the present invention, the acidic circulating fluid can neutralize more ammonia in the gas phase, and ammonia dissipation from the ammonia absorption tower can be reduced. [Brief explanation of the drawing]

[0036] Figure 1 is a schematic front view of a conventional ammonia absorption tower. Figure 2 is a schematic front view of a conventional ammonia absorption tower. Figures 3A and 3B are schematic front views of the ammonia absorption tower of the present invention. Figures 4A and 4B are schematic front views of the ammonia absorption tower of the present invention. Figure 5 is a schematic top view of the spraying apparatus of the present invention. Figures 6A and 6B are schematic top views of the spraying apparatus of the present invention. Figures 7A and 7B are schematic top views of the spraying apparatus of the present invention. Figures 8A and 8B are schematic top views of a spraying apparatus according to a comparative example. Figures 9A and 9B are schematic top and front views, respectively, of a conventional nozzle. Figures 10A and 10B are schematic and detailed top views, respectively, of a conventional spraying device. Figure 11A is a schematic top / front view showing two rotation modes of the nozzle of the present invention. Figure 11B is a schematic top view of the spraying device. Figure 11C is a detailed schematic top view of one spraying device according to the present invention. Figure 11D is a detailed schematic top view of another spraying apparatus of the present invention. Figure 11E is a detailed schematic top view of another spraying apparatus of the present invention.

[0037] [Explanation of reference symbols] 1: Ammonia absorption tower 2: Demister, an internal component of an ammonia absorption tower 3: Spraying device, an internal component of the ammonia absorption tower; 3a to 3f are spraying devices. 4: Gas distributor, an internal component of an ammonia absorption tower. 5: Spraying device, an internal component of the ammonia absorption tower; 5a-5b are spraying devices. 6: Upper circulation pump 7: Lower circulation pump 8: Ammonia-containing gas supply port 9: Gas phase outlet of ammonia absorption tower 10: Upper water supply 11: Lower wastewater outlet 12: Upper ammonium salt-containing solution outlet 13: Lower circulating fluid 14: Upper circulating fluid 15: Acid-containing solution 16: Circulating fluid 17: Circulation pump 18: Spray device inlet 19: First spray pipe of the spraying device 20a, 20b: Second spray pipe of the spraying device 21: Third spray pipe of the spraying device 22: Atomizing nozzle for spraying device

[0038] [Embodiment] Embodiments of the present invention will be described in detail below. However, the scope of protection of the present invention is not limited to these embodiments, but is determined by the appended claims.

[0039] All publications, patent applications, patents, and other references mentioned herein are incorporated herein by reference in their entirety. Unless otherwise defined, all technical and scientific terms used herein are to be understood as having the same meaning as those commonly known to those skilled in the art. In case of any conflict, the definitions herein shall prevail.

[0040] Where this specification introduces materials, substances, processes, procedures, apparatus, components, etc., that begin with phrases such as "well known to those skilled in the art" or "prior art," the subject matter is intended to include not only those that have been conventionally used in the art at the time of filing, but also those that are not currently in common use but will become known in art suitable for similar purposes.

[0041] In the context of this specification, the term “substantially” means a deviation of less than 20%, preferably less than 10% or 5%. All percentages, parts, ratios, etc., stated in this specification are based on weight, and pressures are gauge pressures unless expressly stated.

[0042] In the context of the present invention, two or more embodiments or aspects of the present invention can be arbitrarily combined, and the resulting technical solutions are part of the original disclosure of this specification and are within the scope of the present invention.

[0043] In the context of this specification, for any technical details not described herein, relevant information known in the art shall apply directly.

[0044] According to one embodiment of the present invention, an absorption apparatus is provided, in particular an ammonia absorption tower or a quench tower.

[0045] According to one embodiment of the present invention, the absorption device comprises a housing and a plurality of spraying devices (for example, 2 to 10, preferably 4 to 8) arranged in layers at predetermined vertical intervals along the central axis of the absorption device.

[0046] According to one embodiment of the present invention, each spraying device independently comprises a spray liquid inlet, a first spray pipe that is in fluid communication with the spray liquid inlet, a plurality of (e.g., 10 to 26, preferably 12 to 22) second spray pipes that are in fluid communication with the first spray pipe and are arranged perpendicular to the first spray pipe along both sides thereof, and a plurality of (e.g., 4 to 26, preferably 6 to 22) third spray pipes that are in fluid communication with the second spray pipe and are arranged perpendicular to the second spray pipe along both sides thereof. Furthermore, each spraying device comprises a nozzle located at the end of the third spray pipe and in fluid communication with the third spray pipe.

[0047] The means of connecting the various spray tubes and the third spray tube and nozzles are not particularly limited by the present invention, and conventional connecting means can be used in this technology. For example, fixed connections or detachable connections can be used, preferably screw connections or other detachable connecting means, and are not particularly limited.

[0048] According to one embodiment, the spray liquid is water or an acidic aqueous solution. Preferably, the ammonia-containing gas is brought into countercurrent contact with the acidic aqueous solution flowing from bottom to top as the spray liquid, and the acidic H contained in the aqueous solution is released. + This neutralizes and removes ammonia. Here, an acidic aqueous solution is an aqueous solution of an acidic substance. Examples of acidic substances include, but are not limited to, inorganic acids such as hydrochloric acid, sulfuric acid, and phosphoric acid, or organic acids such as acrylic acid and acetic acid, or acidic salts such as ammonium sulfate.

[0049] According to the present invention, the atomized droplets of the spray liquid sprayed from the nozzle have a very small droplet diameter, typically 50 to 5000 μm. This allows for the effective achievement of gas absorption functions, particularly ammonia removal functions.

[0050] According to one embodiment of the present invention, all the nozzles of one spraying device and all the nozzles of another spraying device substantially coincide in cross-sectional projection. The inventors of the present invention have found that the multiple spraying devices within the absorption device are not only relatively independent individual devices but are also integrated as a whole. The circulating liquid is supplied to the nozzles of each spraying device via the first, second, and third spraying pipes of each spraying device, forming a hollow conical liquid surface centered on the nozzle. The gas comes into contact with the circulating liquid in a countercurrent. The gas cannot come into contact with the conical liquid surface formed by the next upper spraying device unless it passes 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 is neutralized with the acid in the liquid. 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 space between the two layers of spraying devices, i.e., the hollow conical liquid surfaces of the upper and lower layers, can be considered as a gas upward flow path. Since each stage requires an independent liquid-phase circulation spraying device, the rising gas passage has a constant height. The cross-sectional projections of at least one (preferably all) of the first, second, and third spraying pipes are substantially coincide. This means that the projections of the nozzles (centers of the cones) of each layer coincide in cross-section. Therefore, the distribution of ammonia in the gas passage is also uniform. If the projections of the nozzles of the upper and lower layers do not coincide in cross-section, the gas rising passage changes because the hollow conical liquid surfaces of the upper and lower layers are not in the same position. After the rising gas passes through such a gas passage, non-uniformity of the gas distribution between the gas passages is likely to occur, reducing the ammonia absorption effect. According to one embodiment of the present invention, the vertical distance between two adjacent spraying devices (calculated as the vertical distance between the spray liquid inlets of the spraying devices) is 650-1350 mm, preferably 750-1200 mm.

[0051] The inventors of this invention have found that when the projections of the nozzles in the upper and lower layers do not coincide in cross-section, the hollow conical liquid surfaces in the upper and lower layers are not in the same position, which alters the gas rising path. As a result, some paths become wider, while others become narrower. After the rising gas passes through gas paths at different heights, the different gas residence times within the paths make it easy for the gas distribution within the paths to become non-uniform. In other words, when ammonia-containing gas passes through a hollow conical liquid surface, some areas of the liquid surface have an excess of acid, while other areas of the liquid surface have a deficiency of acid, causing ammonia to breakthrough and reducing the ammonia absorption effect.

[0052] The inventors of this invention have also found that when the projections of the upper and lower nozzles do not coincide in cross-section, the spray liquid sprayed from the upper nozzle and the spray liquid sprayed from the lower nozzle undergo more collisions. When two droplets collide, behaviors such as separation, merging, and fragmentation can occur. The inventors have found that when the projections of the upper and lower nozzles do not coincide, the droplets generated by the upper nozzle and the droplets generated by the lower nozzle are more likely to merge upon collision, forming larger droplets. This is undesirable for ammonia absorption.

[0053] According to embodiments of the present invention, when the absorption device is cut in a direction perpendicular to the central axis of the absorption device to obtain a cross-section, at least one (preferably all) selected from the group consisting of a first spray tube, a second spray tube, and a third spray tube of one of the plurality of spray devices and at least one (preferably all) selected from the group consisting of a first spray tube, a second spray tube, and a third spray tube of another plurality of spray devices substantially coincide in projection on the cross-section. That is, since the projections of the nozzles (centers of the cones) of each layer coincide on the cross-section, the ammonia distribution in the gas flow path becomes uniform.

[0054] The inventors of this invention also found that the circulating fluid in each spraying device flows along the first spraying pipe to the second spraying pipe, and further through the third spraying pipe to the nozzle. While the fluid is flowing, the pressure continuously decreases along the path due to the effect of pipe wall resistance. The pressure at the nozzle furthest from the spraying fluid inlet is lower than the pressure at the nozzle closest to the spraying fluid inlet. Because the pressure at the furthest nozzle is relatively the lowest, the atomization effect is also relatively the lowest, and gas-liquid contact at the furthest nozzle becomes insufficient. This makes ammonia dissipation more likely. As the operating cycle of the device is extended, for example, if the device is operated continuously for more than 18 months, solid impurities and viscous heavy components adhere to the inner walls of the pipes, further increasing pipe wall resistance. The atomization effect at the furthest nozzle deteriorates further, resulting in more ammonia dissipation. When the spray liquid inlets of a multi-layered spraying system are on the same side, the furthest nozzles of each layer's spraying system are also on the same side. As a result, gas-liquid contact is weakest in this region, and ammonia in the gas phase is more likely to dissipate from the ammonia absorption tower through this region.

[0055] Based on these findings, according to one embodiment of the present invention, the angle between the projections in the cross-section of the spray liquid inlet of one spraying device and the spray liquid inlet of another spraying device is 180 degrees. In the initial stages of operation of the device, the piping of the spraying devices is relatively clean, so the furthest nozzle of the spraying device is capable of atomizing the spray liquid to produce droplets of 50 to 5000 μm or less. However, after the device has been in continuous operation for 18 months or more, the atomization effect of the nozzle deteriorates at the furthest nozzle of a certain spraying device, causing ammonia dissipation due to poor gas-liquid contact. The dissipated ammonia is captured by the spray liquid from the nearby nozzle of the upper layer spraying device and undergoes a neutralization reaction to form the corresponding salt. Typically, ammonia absorption towers are equipped with multiple layers of spraying devices, such as 3, 4, or 5 or more layers. When the projection angle between the spray liquid inlet of the upper layer (or the top two layers) of the spraying device and the spray liquid inlet of the lower layer (or the bottom two layers) of the spraying device is 180° in cross-section, more ammonia can be absorbed, thereby reducing ammonia dissipation and significantly reducing acid consumption.

[0056] According to one embodiment of the present invention, a plurality of second spray tubes extend substantially parallel to the opposite sides in a horizontal direction perpendicular to the first spray tube. According to one embodiment of the present invention, a plurality of third spray tubes extend substantially parallel to the opposing sides in a horizontal direction perpendicular to the second spray tube.

[0057] According to one embodiment of the present invention, the first spray pipe has an inner diameter of 160 to 480 mm (preferably 200 to 450 mm) and a length of 4500 to 11500 mm (preferably 4800 to 10500 mm).

[0058] According to one embodiment of the present invention, the plurality of second spray pipes are identical or different from one another, each independently having an inner diameter of 30 to 150 mm (preferably 40 to 120 mm) and a length of 1200 to 5750 mm (preferably 1800 to 5250 mm).

[0059] According to one embodiment of the present invention, the plurality of third spray tubes are identical or different from one another, and each independently has an inner diameter of 10 to 60 mm (preferably 15 to 50 mm) and a length of 160 to 325 mm (preferably 175 to 300 mm).

[0060] According to one embodiment of the present invention, the nozzles are identical or different from each other, and each nozzle independently has an inner diameter (referring to the nozzle outlet) of 3 to 20 mm (preferably 6 to 14 mm).

[0061] According to one embodiment of the present invention, each nozzle independently has a spray angle of 65 to 120 degrees (preferably 70 to 100 degrees).

[0062] According to one embodiment of the present invention, the horizontal distance between two adjacent second spray pipes on the first spray pipe is 640 to 1300 mm (preferably 700 to 1200 mm).

[0063] According to one embodiment, the horizontal distance between two adjacent third spray pipes on the same second spray pipe is 320 to 650 mm (preferably 350 to 600 mm).

[0064] According to one embodiment, on two adjacent second spray pipes, the straight-line distance M (as shown in Figures 6A and 6B) between any end of a third spray pipe on one second spray pipe and any end of a third spray pipe on another adjacent second spray pipe is 320 mm or more, preferably 350 mm or more. The inventors of the present invention have found that, in order to improve ammonia absorption efficiency, it is generally necessary that any position in the internal cross-section of the tower be covered by at least two overlapping conical liquid surfaces formed around the nozzles. The same applies to the tower walls. If the distance between the ends of the two spray pipes is too large, it is limited by the nozzle structure, and it is difficult to satisfy the requirement that any position on the tower wall surface limited by the nozzle structure be covered by overlapping liquid surfaces sprayed from two or more nozzles. This increases the likelihood that ammonia will escape through "gaps". If the distance between the ends of the two spray pipes is too small, it is necessary to increase the amount of circulating liquid in the ammonia absorption tower in order to ensure the atomization quality of the spray liquid. This means that the energy consumption of the pump will increase. Furthermore, as shown in Figures 6A and 6B, the vertical projections of the upper and lower layers of the spraying device overlap, so only the upper spraying device and the spray liquid inlets, which are positioned opposite each other, are visible.

[0065] According to one embodiment, the nozzles may be identical or different from each other, and each nozzle independently has a spray liquid discharge speed of 0.5 to 7.5 t / h (preferably 0.9 to 6.5 t / h).

[0066] According to one embodiment of the present invention, among all the spraying devices, the angle between the projections on the cross-section of the spray liquid inlet of any two odd-numbered spraying devices is 0 degrees. The angle between the projections on the cross-section of the spray liquid inlet of any two even-numbered spraying devices is 0°. The angle between the projection on the cross-section of the spray liquid inlet of any odd-numbered spraying device and the projection on the cross-section of the spray liquid inlet of any even-numbered spraying device is 180°. The inventors of the present invention have found that such an arrangement maximizes the uniform distribution of ammonia in the gas phase within the gas flow path.

[0067] According to one embodiment of the present invention, the absorption device has an inner diameter of 4.5 to 11.5 m (preferably 4.8 to 10.5 m).

[0068] According to one embodiment of the present invention, all nozzles of one spraying device and the other spraying device substantially coincide in cross-sectional projection.

[0069] According to one embodiment of the present invention, two nozzles having substantially identical projections have the same spray diameter.

[0070] In one embodiment, the vertical distance between two adjacent spray devices (calculated as the vertical distance between the spray liquid inlets of the spray devices) is 650 to 1350 mm (preferably 750 to 1200 mm). The inventors of the present invention have found that when the vertical distance between two adjacent spray devices is less than 650 mm, for an ammonia absorption tower with the same number of spray devices, the contact time between the rising ammonia-containing gas and the descending circulating liquid becomes insufficient, causing some of the ammonia in the gas phase to directly pass through the hollow conical liquid surface formed by the circulating liquid, thus reducing the ammonia absorption efficiency. The number of spray devices can be increased to ensure sufficient gas-liquid contact time and achieve complete absorption of ammonia in the gas phase, but this increases the total volume of circulating liquid and thus increases the energy consumption of the pump. This is clearly uneconomical. When the vertical distance between two adjacent spray devices exceeds 1350 mm, the height of the tower increases if the number of spray devices remains the same. In other words, the capital investment cost increases. Furthermore, the difficulty of maintenance and repair also increases.

[0071] According to one embodiment of the present invention, the nozzle comprises a nozzle inlet, a rotating chamber, and a nozzle outlet. The rotating chamber is configured such that the spray liquid supplied from the nozzle inlet passes through the rotating chamber and is then discharged from the nozzle outlet in a rotating manner. According to the present invention, the rotating chamber may employ any known rotating chamber structure in the art, as long as it enables the spray liquid to be discharged from the nozzle outlet in a rotating manner after passing through the rotating chamber, and is not particularly limited.

[0072] According to one embodiment of the present invention, each rotating chamber independently has a diameter of 10.0 to 55.0 mm (preferably 13.0 to 45.0 mm).

[0073] According to one embodiment of the present invention, two nozzles having substantially identical projections have the same spray liquid rotation direction. When spray liquids sprayed from nozzles with identical projections of two sprayers collide during descent, the droplet state of each nozzle will be different. Relatively speaking, two nozzles with identical projections but opposite rotation directions are more prone to droplet fragmentation and form more small droplets compared to two nozzles with the same rotation direction. However, if the droplets are too small, they are easily caught and dissipated by the gas.

[0074] According to one embodiment of the present invention, in at least one (preferably all) of the second spray tube, two (preferably all) adjacent nozzles located on the same side of the second spray tube are configured such that the spray liquid is sprayed in the same rotational direction. Typically, the spray liquid is supplied to the rotation chamber tangentially to the nozzle, and after passing through the nozzle outlet, forms a hollow cone with the nozzle outlet as the apex. To achieve uniformity of the spray liquid in the tower, two adjacent nozzles must be positioned equally apart on the cross-section of the tower. That is, the spray liquid enters the nozzles in the same tangential direction. Therefore, the spray liquid on the same side of the second spray tube is sprayed in the same rotational direction, while the two spray liquids on opposite sides of the second spray tube are sprayed in opposite rotational directions. Thus, after the spray liquids sprayed from nozzles on the same second spray tube merge and collide, more droplets maintain their original state and continue to descend along their original direction of motion.

[0075] According to one embodiment of the present invention, all nozzles facing opposite sides of two parallel adjacent second spray tubes are configured to spray the spray liquid in opposite rotational directions. Here, "parallel adjacent" means that they are on the same side of the first spray tube and adjacent to each other, and "facing opposite sides" means the respective sides of the opposing second spray tubes and the other second spray tube, as shown in Figure 11C. Even after the spray liquids sprayed from the two adjacent nozzles of the two parallel adjacent second spray tubes collide during their descent, the droplets maintain their original state and continue to descend and operate. The droplets are neither prone to merging into larger droplets nor prone to splitting into finer droplets.

[0076] According to one embodiment of the present invention, in at least one (preferably all) of the second spray tubes, at least one (preferably all) nozzles located on one side of the second spray tube are configured to spray the spray liquid in rotational direction A. On the other hand, at least one (preferably all) nozzles located on the opposite side of the second spray tube are configured to spray the spray liquid in rotational direction B. Here, rotational direction A is opposite to rotational direction B.

[0077] According to one embodiment of the present invention, rotation direction A is clockwise, and rotation direction B is counterclockwise.

[0078] According to one embodiment of the present invention, among all the nozzles of the spraying device, the number of nozzles that spray the spray liquid in rotation direction A is equal to, or substantially equal to, the number of nozzles that spray the spray liquid in rotation direction B. As mentioned above, the premise for uniform spraying is a uniform distribution of nozzles in the tower, and an axisymmetric distribution is usually preferred. Therefore, the rotation direction of the nozzles appears in axisymmetric pairs. If the rotation direction of all paired nozzles is the same, it means that all nozzles have the same rotation direction. This is because the spray liquid sprayed from two adjacent nozzles is likely to collide and become larger during rotation and descent, and in the process the total effective contact area with gaseous ammonia decreases, thus reducing the ammonia absorption efficiency.

[0079] According to one embodiment of the present invention, in at least one (preferably all) of the second spray tube, two adjacent nozzles (preferably all) located on the same side are configured to spray the spray liquid in opposite rotational directions. The third spray tube extends substantially parallel to both sides opposite the second spray tube in a horizontal direction perpendicular to it. All nozzles on the same horizontal extension of the second spray tube are configured to spray the spray liquid in the same rotational direction, as shown in Figure 11E.

[0080] According to one embodiment of the present invention, in at least one (preferably all) of the second spray tubes, one nozzle located on the second spray tube is configured to spray the spray liquid in a rotational direction A. On the other hand, at least another adjacent nozzle on the same side is configured to spray the spray liquid in a rotational direction B. At least one (preferably all) nozzles located on the opposite side of the second spray tube are configured to spray the spray liquid in a rotational direction A, where rotational direction A is opposite to rotational direction B.

[0081] According to one embodiment, the nozzle comprises a nozzle inlet, a nozzle cavity, and a nozzle outlet. As shown in Figure 9, the cavity has a special structure that forms droplets when the spray liquid supplied from the nozzle inlet passes through the cavity and is discharged from the nozzle outlet. The cavity is not particularly limited and can employ any known structure in this art, as long as it can cause droplets to form when the spray liquid is discharged from the nozzle outlet.

[0082] According to one embodiment, the spray liquid is supplied to the cavity from the top of the nozzle, passes through the nozzle exit, and then forms a solid cone with the nozzle exit as its apex. Typically, two adjacent nozzles are arranged at equal intervals in the cross-section of the tower, and the nozzle projections of multiple sprayers substantially coincide. Even after the spray liquids sprayed from two adjacent nozzles collide during their respective descent, the droplets can continue to descend while maintaining their original state.

[0083] According to one embodiment of the present invention, a method for producing nitriles, in particular (meth)acrylonitrile, is also provided.

[0084] According to one embodiment of the present invention, a method for producing nitrile includes a step of subjecting a hydrocarbon raw material to an ammoxidation reaction to produce a reaction product containing nitrile (referred to as the reaction step), and a step of spraying a spray liquid onto the reaction product to cool the reaction product (referred to as the cooling step). Here, the spray liquid is sprayed onto the reaction product in an absorption apparatus according to any prior embodiment. For this part, details not described in detail here can be directly referred to in the relevant information about the absorption apparatus described above.

[0085] According to one embodiment of the present invention, in the cooling process, the spray liquid and the reaction product are brought into contact in a countercurrent manner.

[0086] According to one embodiment of the present invention, in the cooling process, the flow rate ratio of the spray liquid to the reaction product is 15 to 25:1.

[0087] According to one embodiment of the present invention, in the reaction step, the hydrocarbon raw material is propylene, and the molar ratio of propylene / ammonia / air (calculated as molecular oxygen) is 1:1.1 to 1.3:1.8 to 2.0. This reaction takes place at a reaction temperature of 420 to 440°C, a reaction pressure of 0.03 to 0.14 MPa (gauge pressure), and over a period of 0.06 to 0.15 hours. -1 The reaction is accompanied by a catalyst weight-time-space velocity. Alternatively, the hydrocarbon starting material is isobutylene, the molar ratio of isobutylene / ammonia / air (calculated as molecular oxygen) is 1:1.3-1.6:2.2-2.8, the reaction takes place at a reaction temperature of 395-420°C, a reaction pressure of 0.03-0.14 MPa (gauge pressure), and 0.08-0.17 hours. -1 This is accompanied by a catalytic weight-time-space velocity.

[0088] According to one embodiment of the present invention, depending on the various reaction steps, the composition of the reaction product is generally about 10-20% by weight of C, based on the total weight of the reaction product being 100% by weight. 1-4 Nitrile (e.g., acrylonitrile) and approximately 0.1-5% by weight of C 1-4 The reaction product contains an oxygen-containing compound (e.g., acrolein), approximately 0.1 to 5% by weight of oxygen, approximately 0.1 to 2% by weight of ammonia, and the remainder of impurities. After pre-cooling, the reaction product typically has a temperature of 195 to 235°C and a pressure of 0.03 to 0.14 MPaG. According to the present invention, the technical effects of the production method described above are particularly excellent for this specific reaction product.

[0089] According to one embodiment of the present invention, in the cooling step, the spray liquid cools the reaction product from 195 to 235°C to 81 to 86°C. More preferably, the spray liquid reduces the ammonia content of the reaction product to 150 ppm or less.

[0090] Specific embodiments of the present invention will be described in detail below with reference to the drawings.

[0091] As shown in Figure 4B, according to the present invention, a reaction gas at a temperature of 225°C and unreacted ammonia are supplied to the ammonia absorption tower 1 through the ammonia-containing gas supply port 8. The circulating liquid is drawn from the bottom of the tower and sent to sprayers 3a-3f by the circulation pump 17. Here, sprayers 3a, 3c, and 3e are located on the same side, while sprayers 3b, 3d, and 3f are located on the opposite side from sprayers 3a, 3c, and 3e. The acid-containing liquid is added to the outlet piping of the circulation pump from the acid-containing solution inlet 15. The circulating liquid is sent through the sprayer 3, flows in from the inlet 18 of the sprayer, and reaches the spray nozzle 22 via the first spray pipe 19, the second spray pipe 20a (20b), and the third spray pipe 21 along the direction of the fluid. The ratio of left-rotating spray nozzles to right-rotating spray nozzles is 1:1. The circulating liquid sprayed from the nozzle 22 forms an acidic mist layer in the ammonia absorption tower and absorbs gaseous ammonia from the gas supply port 8. The exhaust gas is discharged from the gas phase outlet 9 of the ammonia absorption tower. The temperature of the exhaust gas at the top is 84°C. As shown in Figure 6A, the projections of the ends of the third spray pipes of the sprayers 3a to 3f coincide on the tower cross-section. A schematic diagram of the nozzle structure of the sprayers and a top view of the sprayers are shown in Figures 11C and 11B, respectively.

[0092] [Examples] The present invention will be described in more detail with reference to the following embodiments, but the present invention is not limited to these embodiments.

[0093] [Example 1] The ammonia absorption tower had a two-stage structure as shown in Figure 3B. The inner diameter of the absorption tower was 7200 mm. The acid-containing circulating liquid was sent to the absorption tower via an upper circulation pump through four sprayers. Here, the fluid direction of the first spray pipes of sprayers 3a and 3c was opposite to that of sprayers 3b and 3d, and the projection angle between two adjacent spray liquid inlets was 180°. A top view of the sprayers is shown in Figure 11B, and a detailed top view of the sprayers is shown in Figure 11C. The vertical distance between two adjacent sprayers was 1200 mm.

[0094] Each spraying device had 16 second spray tubes, to which 11 to 18 third spray tubes were attached. The projections of the ends of the third spray tubes of the spraying devices were identical, and their rotation directions were the same. All nozzles on the same side of the second spray tubes had the same rotation direction. The nozzles on opposite sides of the second spray tubes had opposite rotation directions, and all nozzles on opposing sides of two parallel adjacent second spray tubes had opposite rotation directions. The number of nozzles with the same rotation direction was 480 in each device.

[0095] The vertical distance between two adjacent sprayers was 950 mm. The first spray pipe of the sprayer had an inner diameter of 250 mm and a length of 7000 mm. The distance between the second spray pipes of the sprayer was 820 mm. The second spray pipe had an inner diameter of 100 mm and a length of 2100 mm to 3450 mm. The distance between the third spray pipes of the sprayer was 410 mm. The third spray pipe had an inner diameter of 40 mm and a length of 205 mm. As shown in Figure 6B, the distance between the ends of two adjacent third spray pipes was 580 mm.

[0096] The nozzle outlet diameter was 11.5 mm, the nozzle rotation chamber diameter was 40 mm, and the nozzle spray angle was 75°. The vertical distance from the gas supply inlet 8 to the spraying device 3d was 4000 mm, and the inner diameter of the supply inlet was 1300 mm. The reaction product gas supplied from the supply inlet contained approximately 0.71 wt% ammonia, 13.2 wt% acrylonitrile, and the remainder of impurities such as oxygen, acrolein, and nitrogen, and had a temperature of 225°C and a pressure of 0.06 MPaG.

[0097] The spray liquid discharge rate per nozzle was 4.8 t / h, and the weight ratio of the spray liquid to the reaction product gas supplied from the gas inlet was 20. After operating the apparatus for one month, the residual ammonia concentration in the exhaust gas at the reaction outlet was 39 ppm. After operating the apparatus for 24 months, the residual ammonia concentration in the exhaust gas at the reaction outlet was 41 ppm. The ratio of acid consumption after 24 months of operation to acid consumption after 1 month of operation was 1.02.

[0098] [Example 2] The ammonia absorption tower used was a single-stage structure, as shown in Figure 4B. The inner diameter of the absorption tower was 7200 mm. The acid-containing circulating liquid was sent to the absorption tower from six sprayers via a circulation pump. Here, the fluid direction of the first spray pipes of sprayers 3a, 3c, and 3e was opposite to that of sprayers 3b, 3d, and 3f, i.e., the projection angle between two adjacent spray liquid inlets was 180°. A top view of the sprayers is shown in Figure 11B, and a detailed top view of the sprayers is shown in Figure 11C.

[0099] The vertical distance between two adjacent sprayers was 880 mm. Each sprayer had 14 second spray pipes, each of which had 6 to 14 third spray pipes. The projections of the ends of the third spray pipes of the sprayers coincided, and their rotation directions were identical. All nozzles on the same side of the second spray pipe had the same rotation direction. The nozzles on the opposite sides of the second spray pipe had opposite rotation directions, and all nozzles facing opposite sides of two parallel, adjacent second spray pipes had opposite rotation directions.

[0100] Each sprayer had 456 nozzles with the same rotation direction. The vertical distance between two adjacent sprayers was 920 mm. The first spray pipe of the sprayer had an inner diameter of 200 mm and a length of 7000 mm. The distance between the second spray pipes was 1000 mm. The second spray pipe had an inner diameter of 100 mm and a length of 1850 mm-3450 mm. The distance between the third spray pipes was 500 mm. The third spray pipe had an inner diameter of 40 mm and a length of 250 mm.

[0101] The projections of the ends of the third spray tubes of the spraying device were consistent. As shown in Figure 6B, the distance between the ends of two adjacent third spray tubes was 707 mm. The nozzle outlet diameter was 11.7 mm, the nozzle rotation chamber diameter was 44 mm, and the spray angle was 80°. The vertical distance from the gas supply port 8 to the spraying device 3d was 4000 mm, and the inner diameter of the supply port was 1300 mm. The reaction product gas supplied from the supply port contained approximately 0.71 wt% ammonia, 13.2 wt% acrylonitrile, and the remainder consisting of oxygen, acrolein, nitrogen, etc., and had a temperature of 225°C and a pressure of 0.06 MPaG.

[0102] The spray liquid discharge rate per nozzle was 5.1 t / h, and the weight ratio of the spray liquid to the reaction product gas supplied from the gas inlet was 20. After operating the apparatus for one month, the residual ammonia concentration in the exhaust gas at the reaction outlet was 34 ppm. After operating the apparatus for 24 months, the residual ammonia concentration in the exhaust gas at the reaction outlet was 37 ppm. The ratio of acid consumption after 24 months of operation to acid consumption after 1 month of operation was 1.01.

[0103] [Example 3] As shown in Figure 4A, Example 2 was repeated except that the ammonia absorption tower used had a single-stage structure. The fluid direction of the first spray pipes of sprayers 3a, 3b, and 3c was opposite to that of sprayers 3d, 3e, and 3f. That is, the projections of the spray inlets of the upper three layers of sprayers 3a, 3b, and 3c were substantially the same, and the projections of the spray inlets of the lower three layers of sprayers 3d, 3e, and 3f were also substantially the same. On the other hand, the projection angle between the spray inlets of the upper three layers and the lower three layers was 180°.

[0104] After operating the apparatus for one month, the residual ammonia concentration in the exhaust gas at the reaction outlet was 42 ppm. After operating the apparatus for 24 months, the residual ammonia concentration in the exhaust gas at the reaction outlet was 61 ppm. The ratio of acid consumption after 24 months of operation to acid consumption after 1 month of operation was 1.03.

[0105] [Example 4] As shown in Figure 7A, the projections of the first spray pipes of sprayers 3a, 3c, and 3e coincided in cross-section with those of the first spray pipes of sprayers 3b, 3d, and 3f, while the projections of the second spray pipe, third spray pipe, and nozzle did not coincide in cross-section, except that Example 2 was repeated.

[0106] After operating the apparatus for one month, the residual ammonia concentration in the exhaust gas at the reaction outlet was 78 ppm. After operating the apparatus for 24 months, the residual ammonia concentration in the exhaust gas at the reaction outlet was 95 ppm. The ratio of acid consumption after 24 months of operation to acid consumption after 1 month of operation was 1.05. [Example 5]

[0107] Example 2 was repeated, except that in each spraying apparatus, the nozzles on opposite sides of the seven spray tubes had opposite rotation chamber directions, while the nozzles on opposite sides of the other seven spray tubes had the same rotation chamber direction. After operating the apparatus for one month, the residual ammonia concentration in the exhaust gas at the reaction outlet was 90 ppm. After operating the apparatus for 24 months, the residual ammonia concentration in the exhaust gas at the reaction outlet was 105 ppm. The ratio of acid consumption after 24 months of operation to acid consumption after 1 month of operation was 1.04.

[0108] [Example 6] Example 2 was repeated, except that the projections of the end of the third spray tube of the spraying device matched, and the nozzles of adjacent spraying devices with matching projections had opposite rotation directions. After operating the device for one month, the residual ammonia concentration in the exhaust gas at the reaction outlet was 85 ppm. After operating the device for 24 months, the residual ammonia concentration in the exhaust gas at the reaction outlet was 110 ppm. The ratio of acid consumption after 24 months of operation to acid consumption after 1 month of operation was 1.05.

[0109] [Example 7] Example 2 was repeated, except that in the spraying apparatus, two adjacent nozzles on the same side of the second spray pipe had opposite rotation directions, while all nozzles on the same horizontal extension of the second spray pipe had the same rotation direction. A top view of the spraying apparatus is shown in Figure 11B, and a detailed top view of the spraying apparatus is shown in Figure 11E. After operating the apparatus for one month, the residual ammonia concentration in the exhaust gas at the reaction outlet was 106 ppm. After operating the apparatus for 24 months, the residual ammonia concentration in the exhaust gas at the reaction outlet was 125 ppm. The ratio of acid consumption after 24 months of operation to acid consumption after 1 month of operation was 1.05.

[0110] [Example 8] Example 2 was repeated, except that all nozzles on opposite sides of two adjacent second spray tubes of the spraying apparatus had the same spray liquid rotation direction, while nozzles on both sides of the same second spray tube had opposite spray liquid rotation directions. After operating the apparatus for one month, the residual ammonia concentration in the exhaust gas at the reaction outlet was 108 ppm. After operating the apparatus for 24 months, the residual ammonia concentration in the exhaust gas at the reaction outlet was 121 ppm. The ratio of acid consumption after 24 months of operation to acid consumption after 1 month of operation was 1.04.

[0111] [Example 9] Example 2 was repeated, except that of all pairs of adjacent nozzles on one side of the second spray pipe of the spraying device, only one pair of adjacent nozzles had the same direction of rotation, while the other pair of adjacent nozzles had the opposite direction of rotation, and the nozzles on opposite sides of the same second spray pipe had the opposite direction of rotation. After operating the device for one month, the residual ammonia concentration in the exhaust gas at the reaction outlet was 125 ppm. After operating the device for 24 months, the residual ammonia concentration in the exhaust gas at the reaction outlet was 148 ppm. The ratio of acid consumption after 24 months of operation to acid consumption after 1 month of operation was 1.05.

[0112] [Example 10] Example 1 was repeated, except that all nozzles in the spraying apparatus had the same rotation chamber direction. After operating the apparatus for one month, the residual ammonia concentration in the exhaust gas at the reaction outlet was 129 ppm. After operating the apparatus for 24 months, the residual ammonia concentration in the exhaust gas at the reaction outlet was 149 ppm. The ratio of acid consumption after 24 months of operation to acid consumption after 1 month of operation was 1.06.

[0113] [Example 11] Example 2 was repeated, except that the distance between adjacent third spray pipes was set to 300 mm, and the distance between the ends of two adjacent third spray pipes was set to 300 mm, as shown in Figure 6A. The residual ammonia concentration in the exhaust gas at the reaction outlet was 76 ppm.

[0114] [Example 12] As shown in Figure 6A, Example 2 was repeated except that the distance between the ends of the two adjacent third spray pipes was set to 340 mm. The residual ammonia concentration in the exhaust gas at the reaction outlet was 105 ppm.

[0115] [Example 13] Example 2 was repeated, except that the vertical distance between two adjacent spraying devices was set to 1500 mm and the distance between the third spraying pipes of the spraying devices was set to 500 mm. After operating the device for one month, the residual ammonia concentration in the exhaust gas at the reaction outlet was 117 ppm. After operating the device for 24 months, the residual ammonia concentration in the exhaust gas at the reaction outlet was 139 ppm. The ratio of acid consumption after 24 months of operation to acid consumption after 1 month of operation was 1.05.

[0116] [Example 14] Example 2 was repeated, except that the vertical distance between two adjacent sprayers was set to 700 mm and the distance between the third spray pipes of the sprayers was set to 500 mm. After operating the apparatus for one month, the residual ammonia concentration in the exhaust gas at the reaction outlet was 75 ppm. After operating the apparatus for 24 months, the residual ammonia concentration in the exhaust gas at the reaction outlet was 97 ppm. The ratio of acid consumption after 24 months of operation to acid consumption after 1 month of operation was 1.07.

[0117] [Example 15] Example 2 was repeated, except that the vertical distance between two adjacent spraying devices was set to 1300 mm and the distance between the third spraying pipes of the spraying devices was set to 500 mm. After operating the device for one month, the residual ammonia concentration in the exhaust gas at the reaction outlet was 108 ppm. After operating the device for 24 months, the residual ammonia concentration in the exhaust gas at the reaction outlet was 121 ppm. The ratio of acid consumption after 24 months of operation to acid consumption after 1 month of operation was 1.04.

[0118] [Example 16] Example 2 was repeated, except that the vertical distance between two adjacent spraying units was set to 550 mm. After operating the apparatus for one month, the residual ammonia concentration in the exhaust gas at the reaction outlet was 129 ppm. After operating the apparatus for 24 months, the residual ammonia concentration in the exhaust gas at the reaction outlet was 145 ppm. The ratio of acid consumption after 24 months of operation to acid consumption after 1 month of operation was 1.04.

[0119] [Example 17] Example 2 was repeated, except that the spray liquid discharge rate per nozzle was 8.9 t / h and the weight ratio of the spray liquid to the reaction product gas supplied from the gas inlet was 35. After operating the apparatus for one month, the residual ammonia concentration in the exhaust gas at the reaction outlet was 85 ppm. After operating the apparatus for 24 months, the residual ammonia concentration in the exhaust gas at the reaction outlet was 99 ppm. The ratio of acid consumption after 24 months of operation to acid consumption after 1 month of operation was 1.03.

[0120] [Example 18] Example 2 was repeated, except that the spray liquid discharge rate per nozzle was set to 1.6 t / h and the weight ratio of the spray liquid to the reaction product gas supplied from the gas inlet was set to 8. After operating the apparatus for one month, the residual ammonia concentration in the exhaust gas at the reaction outlet was 135 ppm. After operating the apparatus for 24 months, the residual ammonia concentration in the exhaust gas at the reaction outlet was 169 ppm. The ratio of acid consumption after 24 months of operation to acid consumption after 1 month of operation was 1.05.

[0121] [Example 19] Example 2 was repeated, except that the nozzle outlet diameters on the 1st to 11th second spray tubes of the first spray tube were set to 11.7 mm along the fluid direction, and the nozzle outlet diameters on the 12th to 14th second spray tubes of the first spray tube were set to 11.9 mm. After operating the apparatus for one month, the residual ammonia concentration in the exhaust gas at the reaction outlet was 85 ppm. After operating the apparatus for 24 months, the residual ammonia concentration in the exhaust gas at the reaction outlet was 99 ppm. The ratio of acid consumption after 24 months of operation to acid consumption after 1 month of operation was 1.03.

[0122] [Example 20] As shown in Figure 7B, Example 2 was repeated for sprayers 3a, 3b, 3c, 3d, 3e, and 3f, except that the projections of the first and second spray tubes matched, but the projection of the third spray tube did not. After operating the apparatus for one month, the residual ammonia concentration in the exhaust gas at the reaction outlet was 64 ppm. After operating the apparatus for 24 months, the residual ammonia concentration in the exhaust gas at the reaction outlet was 82 ppm. The ratio of acid consumption after 24 months of operation to acid consumption after 1 month of operation was 1.04.

[0123] [Example 21] Example 2 was repeated in each spraying apparatus, except that in the 10 second spray tubes, two adjacent nozzles on the same side had the same rotation chamber direction, while in the other 4 spray tubes, two adjacent nozzles on the same side had opposite rotation chamber directions. The two nozzles on opposite sides of the second spray tubes of the spraying apparatus had opposite rotation chamber directions. After operating the apparatus for one month, the residual ammonia concentration in the exhaust gas at the reaction outlet was 81 ppm. After operating the apparatus for 24 months, the residual ammonia concentration in the exhaust gas at the reaction outlet was 105 ppm. The ratio of acid consumption after 24 months of operation to acid consumption after 1 month of operation was 1.03.

[0124] [Example 22] Example 2 was repeated in each spraying apparatus, except that in four second spray tubes, two adjacent nozzles on the same side had the same rotation chamber direction, while in the other ten second spray tubes, two adjacent nozzles on the same side had opposite rotation chamber directions. The two nozzles on opposite sides of the second spray tubes of the spraying apparatus had opposite rotation chamber directions. After operating the apparatus for one month, the residual ammonia concentration in the exhaust gas at the reaction outlet was 108 ppm. After operating the apparatus for 24 months, the residual ammonia concentration in the exhaust gas at the reaction outlet was 125 ppm. The ratio of acid consumption after 24 months of operation to acid consumption after 1 month of operation was 1.04.

[0125] [Comparative Example 1] Example 1 was repeated, except that the spray inlets 18 of sprayers 3a, 3c and 3b, 3d were on the same side of the ammonia absorption tower, i.e., the fluid direction in the first spray tube was the same, the projections of the spray inlets of sprayers 3a, 3b, 3c, 3d substantially coincided (see Figure 1), and the projections of the nozzles at the ends of the third spray tubes of sprayers 3a, 3c and sprayers 3b, 3d coincided cross-sectionally (see Figure 5). After operating the apparatus for one month, the residual ammonia concentration in the exhaust gas at the reaction outlet was 85 ppm. After operating the apparatus for 24 months, the residual ammonia concentration in the exhaust gas at the reaction outlet was 253 ppm. The ratio of acid consumption after 24 months of operation to acid consumption after 1 month of operation was 1.13.

[0126] [Comparative Example 2] Example 2 was repeated, except that the spray inlets 18 of sprayers 3a, 3c, and 3e and the spray inlets 18 of sprayers 3b, 3d, and 3f were on the same side of the ammonia absorption tower, i.e., the fluid direction in the first spray tube was the same, the projections of the spray inlets of sprayers 3a, 3b, 3c, 3d, 3e, and 3f were substantially the same (see Figure 2), and the projections of the nozzles at the ends of the third spray tubes of sprayers 3a and 3c were the same as the projections of the nozzles at the ends of the third spray tubes of sprayers 3b and 3d were the same in cross-section (see Figure 5). After operating the apparatus for one month, the residual ammonia concentration in the exhaust gas at the reaction outlet was 73 ppm. After operating the apparatus for 24 months, the residual ammonia concentration in the exhaust gas at the reaction outlet was 223 ppm. The ratio of acid consumption after 24 months of operation to acid consumption after 1 month of operation was 1.13.

[0127] [Comparative Example 3] Example 2 was repeated, except that the projection angle between the spray inlets 18 of sprayers 3a, 3c, and 3e and the spray inlets 18 of sprayers 3b, 3d, and 3f was set to 30°, that is, the fluid direction of the corresponding first spray pipe of the sprayer was set to 30°, and the projection of the end of the third spray pipe of the sprayer did not coincide, as shown in Figure 8B. After operating the apparatus for one month, the residual ammonia concentration in the exhaust gas at the reaction outlet was 130 ppm. After operating the apparatus for 24 months, the residual ammonia concentration in the exhaust gas at the reaction outlet was 343 ppm. The ratio of acid consumption after 24 months of operation to acid consumption after 1 month of operation was 1.15.

[0128] [Comparative Example 4] Example 2 was repeated, except that the projection angle between the spray inlets 18 of sprayers 3a, 3c, and 3e and the spray inlets 18 of sprayers 3b, 3d, and 3f was set to 90°, i.e., the fluid direction of the corresponding first spray pipe of the sprayer was set to 90°, and the projection of the end of the third spray pipe of the sprayer was set to not coincide. After operating the apparatus for one month, the residual ammonia concentration in the exhaust gas at the reaction outlet was 110 ppm. After operating the apparatus for 24 months, the residual ammonia concentration in the exhaust gas at the reaction outlet was 293 ppm. The ratio of acid consumption after 24 months of operation to acid consumption after 1 month of operation was 1.10.

[0129] [Comparative Example 5] Example 2 was repeated, except that the projection angle between the spray inlets 18 of sprayers 3a, 3c, and 3e and the spray inlets 18 of sprayers 3b, 3d, and 3f was 120° in cross-section, i.e., the fluid direction of the corresponding first spray pipe of the sprayer was set to 90°, as shown in Figure 8B, and the projection of the end of the third spray pipe of the sprayer was not matched. After operating the apparatus for one month, the residual ammonia concentration in the exhaust gas at the reaction outlet was 132 ppm. After operating the apparatus for 24 months, the residual ammonia concentration in the exhaust gas at the reaction outlet was 353 ppm. The ratio of acid consumption after 24 months of operation to acid consumption after 1 month of operation was 1.15. [Brief explanation of the drawing]

[0130] [Figure 1] This is a schematic front view of a conventional ammonia absorption tower. [Figure 2] This is a schematic front view of a conventional ammonia absorption tower. [Figure 3A] This is a schematic front view of the ammonia absorption tower of the present invention. [Figure 3B] This is a schematic front view of the ammonia absorption tower of the present invention. [Figure 4A] This is a schematic front view of the ammonia absorption tower of the present invention. [Figure 4B] This is a schematic front view of the ammonia absorption tower of the present invention. [Figure 5] This is a schematic top view of the spraying device of the present invention. [Figure 6A] This is a schematic top view of the spraying device of the present invention. [Figure 6B] This is a schematic top view of the spraying device of the present invention. [Figure 7A] This is a schematic top view of the spraying device of the present invention. [Figure 7B] This is a schematic top view of the spraying device of the present invention. [Figure 8A] This is a schematic top view of a spraying apparatus in a comparative example. [Figure 8B] This is a schematic top view of a spraying apparatus in a comparative example. [Figure 9A] This is a schematic top view of a conventional nozzle. [Figure 9B] This is a schematic front view of a conventional nozzle. [Figure 10A] This is a schematic top view of a conventional spraying device. [Figure 10B] This is a detailed top view of a conventional spraying device. [Figure 11A] This is a schematic top / front view showing two rotation modes of the nozzle of the present invention. [Figure 11B] This is a schematic top view of the spraying device. [Figure 11C] This is a detailed diagram of a schematic top view of one of the spraying devices of the present invention. [Figure 11D] This is a detailed diagram of a schematic top view of another spraying device of the present invention. [Figure 11E] This is a detailed diagram of a schematic top view of another spraying device of the present invention.

Claims

1. An absorption device, The casing and The absorption device comprises a plurality of spraying devices arranged in layers at predetermined vertical intervals along the central axis of the absorption device, Each spraying device operates independently. The spray liquid inlet and A first spray pipe that communicates with the spray liquid inlet, A plurality of second spray pipes are arranged perpendicularly to the first spray pipe along both sides thereof and are in fluid communication with the first spray pipe, A plurality of third spray pipes are arranged perpendicularly to the second spray pipe along both sides thereof and are in fluid communication with the second spray pipe, The nozzle located at the end of the third spray pipe and in fluid communication with it includes, When a cross-section is obtained by cutting the absorbent device in a direction perpendicular to the central axis of the absorbent device, at least one (preferably all) selected from the group consisting of the first spray pipe, the second spray pipe, and the third spray pipe in one of the plurality of spray devices and at least one (preferably all) selected from the group consisting of the first spray pipe, the second spray pipe, and the third spray pipe in the other spray device substantially coincide in the projection of the cross-section. Furthermore, an absorption device wherein the angle between the projection on the cross-section of the spray liquid inlet of one spray device and the projection on the cross-section of the spray liquid inlet of the other spray device is 180°.

2. The absorption device according to claim 1, wherein the horizontal distance between two adjacent second spray pipes on the first spray pipe is 640 to 1300 mm (preferably 700 to 1200 mm), and / or the horizontal distance between two adjacent third spray pipes on the same second spray pipe is 320 to 650 mm (preferably 350 to 600 mm), and / or the straight-line distance M between the end of a third spray pipe on one second spray pipe and the end of a third spray pipe on the other adjacent second spray pipe is 320 mm or more (preferably 350 mm or more).

3. The absorption device according to claim 1, wherein the nozzles are identical or different from each other and each independently has a spray liquid discharge rate of 0.5 to 7.5 tons / hour (preferably 0.9 to 6.5 tons / hour).

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

5. The absorption apparatus according to claim 1, wherein all nozzles of one spraying apparatus and all nozzles of the other spraying apparatus substantially coincide in cross-sectional projection, and / or two nozzles having substantially coincident projections have the same spray diameter.

6. The absorption device according to claim 1, wherein the nozzle comprises a nozzle inlet, a rotating chamber, and a nozzle outlet, and the rotating chamber is configured such that the spray liquid supplied from the nozzle inlet passes through the rotating chamber and is then discharged from the nozzle outlet while rotating.

7. The absorption apparatus according to claim 6, wherein each of the rotating chambers independently has a diameter of 10.0 to 55.0 mm (preferably 13.0 to 45.0 mm), and / or two nozzles having substantially matching projections have the same direction of rotation.

8. The absorption device according to claim 1, wherein in at least one (preferably all) of the second spray tubes, two (preferably all) adjacent nozzles located on the same side of the second spray tube are configured to spray the spray liquid in the same rotational direction.

9. The absorption device according to claim 8, wherein all nozzles positioned on opposing sides of two adjacent second spray pipes are configured to spray the spray liquid in opposite rotational directions.

10. The absorption device according to claim 8, wherein in at least one (preferably all) of the second spray tubes, at least one (preferably all) nozzles located on one side of the second spray tube are configured to spray the spray liquid in rotational direction A, while at least one (preferably all) nozzles located on the opposite side of the second spray tube are configured to spray the spray liquid in rotational direction B, where rotational direction A is opposite to rotational direction B.

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

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

13. The process involves subjecting hydrocarbon raw materials to an ammoxidation reaction to produce a reaction product containing nitriles (referred to as the reaction process), The process includes spraying a spray solution onto the reaction product to cool the reaction product (referred to as the cooling step), The spray liquid is sprayed onto the reaction product in the absorption apparatus according to claim 1, in a process for producing nitrile.

14. The process according to claim 13, wherein in the cooling step, the flow rate ratio of the spray liquid to the reaction product is 15 to 25:1.

Images