Absorption device with opposite spraying liquid inlets and nitrile manufacturing method

Abstract

The invention relates to an absorption device with opposite spray liquid inlets and a nitrile manufacturing method. According to the absorption device, the ammonia absorption rate can be maximized, and ammonia penetration is reduced. The absorption device comprises a shell and a plurality of spraying devices which are arranged in a layered mode in the direction of the central axis of the absorption device at preset vertical intervals. Each spraying device independently comprises a spraying liquid inlet, a first spraying pipe in fluid communication with the spraying liquid inlet, and a plurality of second spraying pipes which are in fluid communication with the first spraying pipe and extend towards the two sides of the first spraying pipe in the direction perpendicular to the first spraying pipe. The absorption device comprises a second spraying pipe, a plurality of third spraying pipes which are in fluid communication with the second spraying pipe and extend towards the two sides of the second spraying pipe in the direction perpendicular to the second spraying pipe, and nozzles which are located at the tail ends of the third spraying pipes and are in fluid communication with the third spraying pipes. The projection of one of the plurality of spraying devices and the projection of at least one of the first spraying pipe, the second spraying pipe and the third spraying pipe of the other of the plurality of spraying devices on the cross section basically coincide; and the included angle between the projection of the spraying liquid inlet of one spraying device and the projection of the spraying liquid inlet of the other spraying device on the cross section is 180 degrees.

Description

Technical Field

[0001] The 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] In the process of generating corresponding nitriles by ammonia or ammoxidation, in order to convert the raw gas such as hydrocarbons as much as possible, the raw gas ammonia is generally excessive, that is, the molar ratio of ammonia to the raw gas hydrocarbon is greater than 1, such as in the ammoxidation of propylene, the ammonia ratio (ammonia to propylene molar ratio) is 1.10-1.35, and in the ammoxidation of aromatic hydrocarbons, the ammonia ratio (ammonia to aromatic hydrocarbon molar ratio) is 4-8, therefore, the reactor outlet tail gas must contain unreacted ammonia. On the one hand, such as in the acrylonitrile production process, acrylonitrile in the reaction gas is prone to polymerization under alkaline conditions, and on the other hand, even if a small amount of unreacted ammonia escapes, it is easy to cause environmental pollution. Therefore, in the ammonia or ammoxidation process, it is necessary to use an absorption device (generally referred to as an ammonia absorber or a quenching tower) to remove the unreacted ammonia in the gas phase with acid or water, and this process is very necessary.

[0003] With the development of production technology, production load is also increasing. Large-scale and large-scale 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 spread in the ammonia absorber through the spraying device, and is in reverse contact with the ammonia-containing gas to absorb, so as to remove the remaining ammonia in the gas phase.

[0004] Patent CN105425849 removes the remaining ammonia by adjusting the amount of added acid to the pH value of the effluent from the ammonia absorber; Patent CN1199940 improves the gas-liquid two-phase mass transfer and heat transfer effect by adding internal components at the bottom of the ammonia absorber, which is essentially to solve the problem of uniform distribution of the ammonia-containing gas phase. However, ammonia penetration will inevitably occur in the ammonia absorber, that is, a small amount of ammonia will still escape, resulting in product loss or environmental pollution in the subsequent refining and separation units.

[0005] Since the spray liquid inlet of the existing device is on the same side, as the operation cycle of the device is extended, solid impurities or other heavy components with higher viscosity in the circulating liquid adhere to the inner wall of the pipeline, causing the liquid flow resistance to increase continuously, resulting in the atomization effect of the nozzle at the end of the spray device to deteriorate, causing more ammonia in the area opposite to the spray liquid inlet to be unabsorbed and penetrate from the ammonia absorption tower to the subsequent equipment. Summary of the invention

[0006] The inventors of the present invention have found that this problem can be solved by arranging the spray liquid inlets of one spray device and another spray device horizontally opposite to each other. The present invention has been completed based on this finding.

[0007] In a first embodiment, the present invention relates to an absorption device, comprising a shell and a plurality of spray devices arranged in layers at a predetermined vertical interval 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 fluidly connected to the spray liquid inlet, a plurality of second spray pipes fluidly connected to the first spray pipe and extending perpendicularly to the first spray pipe to both sides thereof, a plurality of third spray pipes fluidly 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 fluidly connected to 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 of the first spray pipe, the second spray pipe and the third spray pipe selected from 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°.

[0008] In a second embodiment, the present invention relates to 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 the absorption device described in the first embodiment.

[0009] Technical Effects

[0010] According to the spraying device of the present invention, the acidic circulating liquid can neutralize more ammonia in the gas phase and reduce the ammonia escaping from the ammonia absorption tower.

[0011] According to the spraying device of the present invention, the overall consumption of acid can be reduced.

[0012] According to the spraying device of the present invention, even if it is operated for a long period, such as continuously operating for 18 months or even longer, the ammonia absorption effect is still maintained well.

[0013] According to the spraying device of the present invention, even if it is operated for a long period, such as continuously operating for 18 months or even longer, the total consumption of acid can still be maintained at a low level with a small increase (such as below 3%). BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a front view schematic diagram of an ammonia absorption tower in the prior art.

[0015] Figure 2 It is a front view schematic diagram of an ammonia absorption tower in the prior art.

[0016] 3a and 3b are schematic front views of the ammonia absorption tower of the present invention.

[0017] Figure 4A , Figure 4B It is a front view schematic diagram of the ammonia absorption tower of the present invention.

[0018] Figure 5 It is a schematic top view of a spraying device of the present invention.

[0019] Fig. 6A , Figure 6B It is a top view schematic diagram of the spraying device of the present invention.

[0020] Figure 7 It is a schematic top view of a spraying device of the present invention.

[0021] Fig. 8A , Figure 8B This is a top view of the proportional spraying device.

[0022] Description of reference numerals:

[0023] 1: Ammonia absorption tower

[0024] 2: Ammonia absorber internals demister

[0025] 3: Spraying device for internal components of ammonia absorption tower, 3a-3f are spraying devices

[0026] 4: Gas distributor for internal components of ammonia absorber

[0027] 5: Spraying device for internal components of ammonia absorption tower, 5a-5b is the spraying device

[0028] 6: Upper circulation pump

[0029] 7: Lower circulation pump

[0030] 8: Ammonia-containing gas feed

[0031] 9: Gas phase discharge from ammonia absorption tower

[0032] 10: Rehydration in the upper part

[0033] 11: Discharge of wastewater from the lower section

[0034] 12: Discharge of ammonium salt solution from the upper section

[0035] 13: Lower circulating fluid

[0036] 14: Upper circulating fluid

[0037] 15: Acid solution

[0038] 16: Circulating fluid

[0039] 17: Circulation pump

[0040] 18: Spraying device inlet

[0041] 19: Spraying device first spray pipe

[0042] 20a, 20b: Second spray pipe of the spraying device

[0043] 21: The third spray pipe of the spray device

[0044] 22: Spraying device atomizing nozzle DETAILED DESCRIPTION

[0045] The specific embodiments of the present invention are described in detail below, but it should be pointed out that the protection scope of the present invention is not limited by these specific embodiments, but is determined by the claims in the appendix.

[0046] 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 conventionally understood by those skilled in the art. In the event of a conflict, the definitions in this specification shall prevail.

[0047] 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, etc., the objects introduced by the prefix cover 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 recognized in the art as being suitable for similar purposes.

[0048] In the context of this specification, by substantially it is meant a deviation of no more than 20%, preferably no more than 10% or 5%.

[0049] Unless otherwise specified, all percentages, parts, ratios, etc. mentioned in this specification are based on weight and pressure is gauge pressure.

[0050] 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 protection scope of the present invention.

[0051] In the context of this specification, all technical details etc. not mentioned are directly applicable to relevant information known in the art.

[0052] According to one embodiment of the present invention, it relates to an absorption device, in particular an ammonia absorption tower or a quenching tower.

[0053] 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 a predetermined vertical interval along the central axis direction of the absorption device.

[0054] 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 on 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 on both sides thereof, and a nozzle located at the end of the third spray pipe and fluidically connected to it.

[0055] The present invention has no specific limitation on the connection method between the spray pipes and between the third spray pipe and the nozzle, and conventional connection methods in the art can be used. For example, fixed connection or detachable connection can be used, preferably threaded connection, or other detachable connection methods, which are not specifically limited.

[0056] 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 as the spraying liquid from bottom to top in reverse from top to bottom, and the acidic H+ contained in the aqueous solution reacts with ammonia to 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, phosphoric acid; may also be an organic acid, such as acrylic acid, acetic acid; may also be an acidic salt, such as ammonium sulfate, without specific limitation.

[0057] 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.

[0058] The inventor of the present invention has found 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 spraying pipe, the second spraying pipe, and the third spraying pipe of each spraying device, and a hollow conical liquid surface is formed with the nozzle as the center. The gas contacts the circulating liquid in reverse. The gas can contact the conical liquid surface formed by the upper spraying device only after passing through the conical liquid surface formed by the lower spraying device. At the moment when the gas passes through the conical liquid surface, the ammonia in the gas reacts 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 finally completely neutralized by the acid in the circulating liquid. 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 circulating spraying device, the rising gas channel has a certain height. In this channel, the gas phase ammonia needs to have enough residence time to achieve uniformity. According to one embodiment of the present invention, 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.

[0059] The inventor of the present invention has found that if the projections of the upper layer of nozzles and the lower layer of nozzles on the cross section do not overlap, since the upper and lower hollow conical liquid surfaces are not in the same position, the gas channel of the rising gas is changed, and some channels become "wider" and some channels become "narrower". After the rising gas passes through the gas channels at different heights, due to the different gas residence times in the channels, there is a problem of uneven gas distribution in the channels. That is, when the ammonia-containing gas passes through the hollow conical liquid surface, some areas of the liquid surface have excess acid, while the other parts of the liquid surface have insufficient acid, resulting in ammonia penetration, thereby reducing the ammonia absorption effect.

[0060] The inventor of the present invention has also found that if the projections of the upper layer of nozzles and the lower layer of nozzles on the cross section do not overlap, the spray liquid sprayed by the upper layer of nozzles and the lower layer of nozzles will have more collisions. When two droplets collide, there are separation, aggregation, and fragmentation. The inventor has found that when the projections of the upper layer of nozzles and the lower layer of nozzles on the cross section do not overlap, the droplets generated by the upper layer of nozzles and the droplets generated by the lower layer of nozzles are more likely to aggregate during the collision process to form larger droplets, which is not conducive to the absorption of ammonia.

[0061] According to one embodiment of the present invention, when the absorption device is cut 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 multiple spray devices and another of the multiple 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, so that ammonia is evenly distributed in the gas rest channel.

[0062] The inventor of the present invention also found that the circulating liquid of each spraying device flows along the first spraying pipe to the second spraying pipe to the third spraying pipe until the nozzle. During the flow of the fluid, the pressure along the way is continuously reduced by the resistance of the pipe wall. The pressure at the nozzle far from the spraying liquid inlet is lower than the pressure at the nozzle near the spraying liquid inlet. Since the pressure at the farthest nozzle is relatively the lowest, the atomization effect is relatively the worst, resulting in insufficient gas-liquid contact at the farthest nozzle, which easily causes ammonia to escape. With the extension of the operation cycle of the device, such as the continuous operation of the device for 18 months or even longer, the solid impurities and heavy components with high viscosity in the pipeline adhere to the pipe wall, the resistance of the pipe wall is further increased, and the atomization effect at the far nozzle becomes worse, causing more ammonia to escape. If the spraying liquid inlet of the multi-layer spraying device is on the same side, since the far nozzles of each layer of the spraying device are on the same side, the gas-liquid contact in this area is the weakest, and the ammonia in the gas phase is more likely to escape from the ammonia absorption tower from this area.

[0063] 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 pipeline of the spray device is relatively clean, the distal nozzle of the spray device is sufficient to atomize the spray liquid to produce 50-5000 μm or smaller droplets. After the device has been running continuously for 18 months or even longer, although the ammonia escapes due to poor gas-liquid contact at the farthest nozzle of a spray device due to the poor atomization effect of the nozzle, 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 generate 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 projection angle between the spray liquid inlet of the upper (or second) layer of spray devices and the spray liquid inlet of the next (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 can also reduce acid consumption to a greater extent.

[0064] According to one embodiment of the present invention, the plurality of second spraying pipes extend substantially in parallel along a horizontal direction perpendicular to the first spraying pipe toward opposite sides thereof.

[0065] According to one embodiment of the present invention, the plurality of third spraying pipes extend substantially in parallel along a horizontal direction perpendicular to the second spraying pipe toward opposite sides thereof.

[0066] 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).

[0067] 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 inner diameter independently of 30-150 mm (preferably 40-120 mm) and a length independently of 1200-5750 mm (preferably 1800-5250 mm).

[0068] 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).

[0069] According to one embodiment of the present invention, the nozzles are the same or different from each other, and the inner diameter (referring to the nozzle outlet) is independently 3-20 mm (preferably 6-14 mm).

[0070] According to one embodiment of the present invention, the diameters of the rotation chambers of the nozzles are independently 10.0-55.0 mm (preferably 13.0-45.0 mm).

[0071] According to one embodiment of the present invention, the spraying angles of the nozzles are independently 65-120° (preferably 70-100° mm).

[0072] According to one embodiment of the present invention, on the first spray pipe, the horizontal distance between two adjacent second spray pipes is 640-1300 mm (preferably 700-1200 mm).

[0073] According to one embodiment of the present invention, on the same second spraying pipe, the horizontal distance between two adjacent third spraying pipes is 320-650 mm (preferably 350-600 mm).

[0074] According to one embodiment of the present invention, on two adjacent second spray pipes, the straight-line distance M (e.g., Fig. 6A , Figure 6B The distance between the ends of the two spray pipes is not less than 320 mm, preferably not less than 350 mm. The inventors of the present invention have found that in order to improve the ammonia absorption efficiency, 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, including the tower wall. If the distance between the ends of the two spray pipes is too large, it is difficult to meet the overlap of the liquid surfaces sprayed by more than two nozzles at any position on the tower wall due to the limitation of the nozzle structure, which increases 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 amount of circulating liquid in the ammonia absorption tower will inevitably increase, that is, the energy consumption of the pump will increase.

[0075] According to one embodiment of the present invention, the nozzles are the same or different from each other, and the spraying liquid spraying amount is independently 0.5-7.5 t / h (preferably 0.9-6.5 t / h).

[0076] According to one embodiment of the present invention, among all the spraying devices, the angle between the projections of the spraying liquid inlets of any two odd-numbered spraying devices on the cross section is 0°, the angle between the projections of the spraying liquid inlets of any two even-numbered spraying devices on the cross section is 0°, and the angle between the projections of the spraying liquid inlets of any odd-numbered spraying device and any even-numbered spraying device on the cross section is 180°. The inventors of the present invention have found that such an arrangement can satisfy the uniform distribution of ammonia in the gas phase in the gas channel as much as possible.

[0077] 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).

[0078] 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.

[0079] According to one embodiment of the present invention, two nozzles whose projections substantially coincide with each other have the same spray diameter.

[0080] 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 inlet of the spraying device) is 650-1350mm (preferably 750-1200mm). The inventor of the present invention found that when the vertical spacing between two adjacent spraying devices is less than 650mm, for an ammonia absorption tower with the same number of spraying devices, due to the 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 be increased, and the energy consumption of the pump will be increased, which is obviously uneconomical. When the vertical spacing between two adjacent spraying devices is greater than 1350mm, in the case 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 and repair will be increased.

[0081] According to one embodiment of the present invention, it also relates to a method for producing nitrile, in particular, a method for producing (meth)acrylonitrile.

[0082] According to one embodiment of the present invention, the manufacture method of the nitrile comprises making hydrocarbon feedstock ammoxidation reaction and manufacturing the step (referred to as reaction step) of the reaction product comprising nitrile and spraying spraying liquid to the reaction product to cool the reaction product (referred to as cooling step). At this, in the absorption unit described in any one of the aforementioned embodiments, the reaction product is sprayed with the spraying liquid. For this reason, the content without detailed description in this part can be directly referred to the related content described for the absorption unit described above.

[0083] According to one embodiment of the present invention, in the cooling step, the spraying liquid contacts the reaction product in a countercurrent manner.

[0084] 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.

[0085] According to one embodiment of the present invention, in the reaction step, the hydrocarbon feedstock is propylene, the molar ratio of propylene / ammonia / air (in terms of 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 (in terms of 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 .

[0086] According to one embodiment of the present invention, in the cooling step, the spraying liquid cools the temperature of the reaction product from 425-445°C (or 390-420°C) to 81-86°C (or 87-95°C).

[0087] According to one embodiment of the present invention, in the cooling step, the spraying liquid reduces the ammonia content of the reaction product to below 150 ppm.

[0088] A specific embodiment of the present invention is described in detail below by way of example with reference to the accompanying drawings.

[0089] like Figure 4BAs shown, according to the present invention, the reaction gas with a temperature of 440°C and unreacted ammonia enter the ammonia absorption tower 1 from the ammonia-containing gas feed port 8, the circulating liquid is extracted from the bottom of the tower and sent to the spraying device 3a-spraying device 3f through the circulating pump 17, wherein the spraying devices 3a\3c\3e are on the same side, and the spraying devices 3b\3d\3f are on the opposite side to the spraying devices 3a\3c\3e, the acid-containing liquid is added to the circulating pump outlet pipeline from the acid solution port 15, the circulating liquid passes through the spraying device 3, enters from the inlet 18 of the spraying device 3, and passes through the first spraying pipe 19, the second spraying pipe 20a (20b), and the third spraying pipe 21 along the fluid direction to the atomizing nozzle 22, and the circulating liquid is sprayed from the nozzle 22 to form an acid mist liquid layer in the ammonia absorption tower, absorbing the gas ammonia from the gas feed port 8, and the tail gas is discharged from the ammonia absorption tower from 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 spray devices 3a-3f on the cross section of the tower coincide, as shown in FIG. Fig. 6A shown.

[0090] Example

[0091] The present invention is further described in detail below using examples, but the present invention is not limited to these examples.

[0092] Example 1

[0093] Ammonia absorption tower Figure 3B The two-stage structure has an inner diameter of 7200mm. The acid-containing circulating liquid is sent to the absorption tower through the upper circulating pump through 4 spraying devices. The fluid directions in the first spraying pipes of spraying devices 3a, 3c and 3b, 3d are opposite, that is, the projection angle of two adjacent spraying liquid inlets is 180°. The vertical spacing between two adjacent spraying devices is 1200mm. Each spraying device has 16 second spraying pipes, and the second spraying pipes are provided with 11 to 18 third spraying pipes. The inner diameter of the first spray pipe of the spray device is 250mm, and the length of the first spray pipe is 7000mm; the spacing of the second spray pipes of the spray device is 820mm, the inner diameter of the second spray pipe is 100mm, and the length of the second spray pipe is 2100mm-3450mm; the spacing of the third spray pipes of the spray device is 410mm, the inner diameter of the third spray pipe is 40mm, and the length of the third spray pipe is 205mm; the projections of the third spray ends of the spray device overlap, and the adjacent two third spray pipes are as follows Figure 6BThe end distance is 580mm; the spraying device has 960 nozzles, the nozzle outlet diameter is 11.5mm, the nozzle rotation chamber diameter is 40mm, the nozzle spray angle is 75°, the spray liquid spraying amount of each nozzle is 4.8t / h, and the weight ratio of the spray liquid to the reaction gas entering from the gas inlet is 20. After the device was operated for 1 month, the residual ammonia concentration of the reaction outlet tail gas was 39ppm, and the device was operated for 24 months, and the residual ammonia concentration of the reaction outlet tail gas was 41ppm; the acid consumption of the device for 24 months of operation / the acid consumption of the device for 1 month of operation is 1.02.

[0094] Example 2

[0095] Ammonia absorption tower Figure 4B The one-stage structure has an inner diameter of 7200mm. The acid-containing circulating liquid is delivered to the absorption tower through 6 spraying devices via a circulating pump. The fluid directions in the first spraying pipes of spraying devices 3a, 3c, 3e and 3b, 3d, 3f are opposite, that is, the projection angle of two adjacent spraying liquid inlets is 180°. The vertical spacing between two adjacent spraying devices is 880mm. Each spraying device has 14 second spraying pipes, and the second spraying pipes are provided with 6 to 14 third spraying pipes. The inner diameter of the first spray pipe of the spray device is 200mm and the length is 7000mm; the spacing of the second spray pipe of the spray device is 1000mm, the inner diameter of the second spray pipe is 100mm, and the length of the second spray pipe is 1850mm-3450mm; the spacing of the third spray pipe of the spray device is 500mm, the inner diameter of the third spray pipe is 40mm, and the length of the third spray pipe is 250mm. The projections of the third spray ends of the spray device overlap. If two adjacent third spray pipes are Figure 6B The end distance shown is 707mm. The spraying device has a total of 912 nozzles, the nozzle outlet diameter is 11.7mm, the nozzle rotation chamber diameter is 44mm, the spraying angle is 80°, the spraying liquid spraying amount of each nozzle is 5.1t / h, and the weight ratio of the spraying liquid to the reaction gas entering from the gas inlet is 20. After the device was operated for 1 month, the residual ammonia concentration of the reaction outlet tail gas was 34ppm, and the device was operated for 24 months, and the residual ammonia concentration of the reaction outlet tail gas was 37ppm; the acid consumption of the device for 24 months of operation / the acid consumption of the device for 1 month of operation is 1.01.

[0096] Example 3

[0097] The same as Example 2, the only difference is that the ammonia absorption tower adopts Figure 4AThe one-stage structure has opposite directions of the fluid in the first spray pipes of the spray devices 3a, 3b, 3c and 3d, 3e, 3f, that is, the spray inlet projections of the upper three layers of spray devices 3a, 3b, 3c basically overlap, and the spray inlet projections of the lower three layers of spray devices 3d, 3e, 3f also basically overlap, and the angle between the upper three layers and the lower three layers of spray inlet projections is 180°. After the device was operated for 1 month, the residual ammonia concentration of the reaction outlet tail gas was 42ppm, and the residual ammonia concentration of the reaction outlet tail gas was 61ppm after the device was operated 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 was 1.03.

[0098] Example 4

[0099] The same as Example 1, the only difference is that the ammonia absorption tower adopts Figure 3A The two-stage structure has opposite directions of the fluid in the first spray pipes of the spray devices 3a, 3b and 3c, 3d, that is, the spray inlet projections of the upper two layers of spray devices 3a, 3b basically overlap, and the spray inlet projections of the lower two layers of spray devices 3d, 3e also basically overlap, and the angle between the upper two layers and the lower two layers of spray inlet projections is 180°. After the device was operated for 1 month, the residual ammonia concentration of the reaction outlet tail gas was 45ppm, and the residual ammonia concentration of the reaction outlet tail gas was 75ppm after 24 months of operation. The acid consumption of the device in 24 months of operation / the acid consumption of the device in 1 month of operation was 1.03.

[0100] Example 5

[0101] The same as Example 2, the only difference is 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 75 ppm, the device is operated for 24 months, the residual ammonia concentration of the reaction outlet exhaust gas is 97 ppm, and the acid consumption of the device operating for 24 months / the acid consumption of the device operating for 1 month is 1.04.

[0102] Example 6

[0103] The same as embodiment 2, the only difference is that the first spray pipes of the spray devices 3a, 3c, 3e and 3b, 3d, 3f overlap in cross section, while the second spray pipe, the third spray pipe and the nozzle do not overlap in cross section. Figure 7 As shown, after the device has been in operation for 1 month, the residual ammonia concentration in the tail gas at the reaction outlet is 78 ppm, after the device has been in operation for 24 months, the residual ammonia concentration in the tail gas at the reaction outlet is 95 ppm, and the acid consumption of the device in operation for 24 months / the acid consumption of the device in operation for 1 month is 1.05.

[0104] Comparative Example 1

[0105] The same as Example 1, the only difference is that the spray inlets 18 of the spray devices 3a, 3c and 3b, 3d are on the same side of the ammonia absorption tower, that is, the direction of the fluid in the first spray pipe is the same, and the spray inlet projections of the spray devices 3a, 3b, 3c and 3d are basically overlapped, (such as Figure 1 As shown), and the projections of the nozzles at the end of the third spray pipes of the spray devices 3a, 3c and 3b, 3d on the cross section do not overlap (as shown Fig. 8A The residual ammonia concentration of the tail gas at the reaction outlet was 85 ppm after the device was operated for 1 month. The residual ammonia concentration of the tail gas at the reaction outlet was 223 ppm after the device was operated for 24 months. The acid consumption of the device at 24 months of operation / the acid consumption of the device at 1 month of operation was 1.13.

[0106] Comparative Example 2

[0107] The same as the second embodiment, the only difference is that the spray inlets 18 of the spray devices 3a, 3c, 3e and 3b, 3d, 3f are projected at 150° on the cross section, that is, the fluid directions of the corresponding first spray pipes of the spray devices are 150°, and the projections of the ends of the third spray pipes of the spray devices do not overlap, such as Figure 8B After the device was operated for 1 month, the residual ammonia concentration of the tail gas at the reaction outlet was 130ppm. After the device was operated for 24 months, the residual ammonia concentration of the tail gas at the reaction outlet was 343ppm. The acid consumption of the device in 24 months of operation / the acid consumption of the device in 1 month of operation was 1.15.

Claims

1. An absorption device, comprising a shell and a plurality of (e.g., 2-10, preferably 4-8) spraying devices arranged in layers at a predetermined vertical interval along the central axis direction 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 fluidically connected thereto, wherein when the absorption device is cross-cut 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°.

2. The absorption device according to claim 1, wherein the plurality of second spray pipes extend substantially parallel to the opposite sides of the first spray pipe perpendicularly to the first spray pipe, and / or the plurality of third spray pipes extend substantially parallel to the opposite sides of the second spray pipe perpendicularly to the second spray pipe.

3. The absorption device according to claim 1, 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 plurality of second spray pipes are the same or different from each other, and the inner diameters are independently 30-150 mm (preferably 40-120 mm) and the lengths are independently 1200-5750 mm (preferably 1800-5250 mm), and / or the plurality of third spray pipes are the same or different from each other, and the inner diameters are independently 10-60 mm (preferably 15-50 mm) and the lengths are independently 160-325 mm (preferably 175-300 mm).

4. The absorption device according to claim 1, wherein the nozzles are the same or different from each other, the inner diameter (referring to the nozzle outlet) is independently 3-20 mm (preferably 6-14 mm), the diameter of the rotation chamber is independently 10.0-55.0 mm (preferably 13.0-45.0 mm), and the spraying angle is independently 65-120° (preferably 70-100° mm).

5. 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).

6. 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).

7. 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°.

8. The absorption device according to claim 1, wherein the inner diameter of the absorption device is 4.5-11.5 m (preferably 4.8-10.5 m).

9. 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.

10. 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).

11. A method for producing nitrile, comprising a step of subjecting a hydrocarbon feedstock 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 according to claim 1.

12. The production method according to claim 11, wherein in the cooling step, the spraying liquid contacts the reaction product in a countercurrent manner.

13. The manufacturing method according to claim 11, wherein in the cooling step, the flow ratio of the spraying liquid to the reaction product is 15-25:

1.

14. The production method according to claim 11, wherein in the reaction step, the hydrocarbon feedstock is propylene, the molar ratio of propylene / ammonia / air (in terms of 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 (in terms of 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 .

15. The manufacturing method according to claim 11, wherein in the cooling step, the spraying liquid cools the temperature of the reaction product from 425-445°C (or 390-420°C) to 81-86°C (or 87-95°C), and / or, in the cooling step, the spraying liquid reduces the ammonia content of the reaction product to below 150 ppm.

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