CN114522514B

CN114522514B - Gas-phase quenching circulation absorption tower for preparing acrylic acid by propylene oxidation method

Info

Publication number: CN114522514B
Application number: CN202210163399.XA
Authority: CN
Inventors: 李金江; 王兵杰; 荣洪杰
Original assignee: Shandong Lanwan New Material Co ltd
Current assignee: Shandong Lanwan New Material Co ltd
Priority date: 2022-02-22
Filing date: 2022-02-22
Publication date: 2023-07-04
Anticipated expiration: 2042-02-22
Also published as: CN114522514A

Abstract

The invention relates to a gas-phase quenching circulation absorption tower for preparing acrylic acid by propylene oxidation, which relates to the field of chemical production equipment and comprises a tower body composed of a plurality of cylinders with different thicknesses, a gas-phase inlet pipe fixedly connected to the lower part of the tower body and used for introducing gas phase, a separator arranged in the gas-phase inlet pipe and used for rotationally separating the gas phase, a plurality of sprayers distributed in the inner cavity of the tower body at intervals, and two distributors distributed at the upper part and the lower part of the tower body, wherein different cylinders are internally provided with packing with different densities and trays with different layers, and the sprayers distributed near the gas-phase inlet pipe partially are used for repeatedly transferring mass and heat between desalted water and the gas phase introduced into the tower body through the packing, the trays and the distributors and the gas phase inlet pipe downwards.

Description

Gas-phase quenching circulation absorption tower for preparing acrylic acid by propylene oxidation method

Technical Field

The invention relates to the technical field of chemical production equipment, in particular to a gas-phase quenching circulating absorption tower for preparing acrylic acid by a propylene oxidation method.

Background

The quenching absorption section is a necessary process stage from the gas phase to the liquid phase in the acrylic acid production by propylene oxidation. The existing domestic propylene oxidation method for producing acrylic acid can be divided into two important sections, namely a reaction section and a gas phase absorption rectifying section, and the absorption rectifying section after the reaction directly influences the yield and the energy consumption of the product.

The absorption rectifying section comprises three or four parts as follows: the quenching absorption section, the light component removing section, the acetic acid removing section and the product refining section are combined. The absorption rectifying section is divided into three parts and four parts, the quenching absorption is a processing section which is necessary for reacting gas phase to liquid phase, acrylic acid in the gas phase is absorbed by spray water, the concentration of acrylic acid in the tower kettle is increased, and excessive air components in reactants, particularly gas phase components insoluble in water such as oxygen, nitrogen and the like are removed.

The main device of the quenching absorption section is a quenching absorption tower, and the efficiency of the quenching absorption tower directly influences the yield and the energy consumption of the whole absorption and rectification section. The existing quenching absorption section adopts an absorption tower to separate a gas phase and a liquid phase, so that the gas phase loss is large and the yield is low.

Accordingly, in order to solve the above-mentioned drawbacks, it is desirable to provide a gas-phase quenching recycle absorption tower for producing acrylic acid by propylene oxidation.

Disclosure of Invention

First, the technical problem to be solved

The invention aims to solve the technical problems of large gas loss at the top of a current quenching absorption tower and low acrylic acid yield.

(II) technical scheme

In order to solve the technical problems, the invention provides a gas-phase quenching circulating absorption tower for preparing acrylic acid by propylene oxidation, which comprises a tower body composed of a plurality of cylinders with different thicknesses, a gas-phase inlet pipe fixedly connected to the lower part of the tower body and used for introducing gas phase, a separator arranged in the gas-phase inlet pipe and used for rotationally separating the gas phase, a plurality of sprayers distributed in the inner cavity of the tower body at intervals, and two distributors distributed at the upper part and the lower part of the tower body, wherein different cylinders are internally provided with packing with different densities and trays with different layers, and desalted water is repeatedly transferred and heat with the gas phase introduced into the tower body through the packing, the trays and the distributors downwards through part of the sprayers near the gas-phase inlet pipe.

As a further explanation of the present invention, it is preferable that the tower body comprises a cylinder I, a cylinder II, a cylinder III, a cylinder IV and a cylinder V, wherein the cylinder I, the cylinder II, the cylinder III, the cylinder IV and the cylinder V are fixedly connected by stacking and welding from bottom to top, the outer diameter of the cylinder I is the largest, and the outer diameters of the cylinder II, the cylinder III, the cylinder IV and the cylinder V are the same.

As a further explanation of the present invention, it is preferable that the wall thickness of the cylinder I is 15 to 18mm, the wall thickness of the cylinder II is 15 to 18mm, the wall thickness of the cylinder III is 13 to 16mm, the wall thickness of the cylinder IV is 10 to 14mm, and the wall thickness of the cylinder V is 10 to 14mm.

As a further explanation of the present invention, it is preferable that the reinforcing cylinder is welded to the outside of the cylinder v, and the reinforcing cylinder has a ring-shaped structure surrounded by steel plates.

As a further explanation of the present invention, it is preferable that the cylinder II is filled with a cylinder II filler, the cylinder III is filled with a cylinder III filler, the cylinder IV is filled with a cylinder IV filler, and the cylinder V is filled with a cylinder V filler, wherein the bulk density from the cylinder II filler to the cylinder V filler is sequentially increased, and the filler height is sequentially decreased.

As a further explanation of the present invention, preferably, the filler is one or more selected from stainless steel 304L, stainless steel 316L, orifice plate corrugated filler, calendared orifice ring filler or wire mesh filler, and the inclination angle of the filler is set between 30 DEG and 60 deg.

As a further explanation of the present invention, it is preferable that a foam breaking net is filled between the cylinder I and the cylinder II, and oblate round filaments with the foam breaking net of 0.08-0.30 mm are woven and formed, and the net surface of the foam breaking net is pressed with waves with an oblique angle of 20-45 degrees and a depth of 5-7 mm.

As a further explanation of the present invention, it is preferable that the number of the separators is three, the gas phase inlet pipe is a T-shaped three-way pipe, two separators are respectively arranged at two gas inlet pipe openings in the horizontal direction of the gas phase inlet pipe, and the other separator is arranged at a gas outlet pipe opening in the vertical direction of the gas phase inlet pipe; the separator comprises a bracket, a fan blade seat and fan blades, wherein the bracket is fixedly connected with the inner wall of the gas-phase inlet pipe, the fan blade seat is rotationally connected to the middle part of the bracket through a liquid self-lubricating bearing, a plurality of fan blades are fixedly connected to the fan blade seat at annular intervals, and the deflection angle of the fan blades is set to be 30-60 degrees.

As a further explanation of the invention, preferably, two sprayers are distributed in the cylinder I at intervals along the vertical direction, the sprayer with low height is fixedly connected with a secondary reflux spray pipe, and the sprayer with high height is fixedly connected with a main reflux spray pipe; the bottom of the cylinder I is fixedly connected with a liquid phase outlet pipe, and the secondary reflux spray pipe and the main reflux spray pipe are both communicated with the liquid phase outlet pipe; a sprayer is also arranged in the cylinder V, and a desalted water spray pipe is fixedly connected to the sprayer in the cylinder V, and desalted water is introduced into the desalted water spray pipe.

As a further explanation of the present invention, preferably, the distributor includes a top liquid receiving tank rod, a middle liquid receiving tank rod, a bottom liquid receiving tank rod and connecting rods, the top liquid receiving tank rod, the middle liquid receiving tank rod and the bottom liquid receiving tank rod are distributed from top to bottom at intervals, a plurality of connecting rods are fixedly connected between the top liquid receiving tank rod, the middle liquid receiving tank rod and the bottom liquid receiving tank rod at intervals so as to support the top liquid receiving tank rod, the middle liquid receiving tank rod and the bottom liquid receiving tank rod, the tank edges of the top liquid receiving tank rod, the middle liquid receiving tank rod and the bottom liquid receiving tank rod are provided with a plurality of liquid receiving holes, and the bottoms of the top liquid receiving tank rod and the bottom liquid receiving tank rod are provided with two residual liquid discharging holes; the two distributors are respectively arranged in the cylinder I and the cylinder V, the distributor in the cylinder I is positioned between the two sprayers, and the distributor in the cylinder V is positioned below the sprayers in the cylinder V.

(III) beneficial effects

The technical scheme of the invention has the following advantages:

the invention designs that the lower tower barrel body plate is thick, and the upper barrel body plate is thin, thereby not only reducing equipment investment, but also keeping the consistency of the whole corrosion degree of the equipment and prolonging the service life of the tower body; in addition, a gas-liquid self-help separator is adopted for separation, a double-liquid-phase distributor is designed to be circularly and uniformly distributed, the absorption efficiency of acrylic acid is enhanced, and the controllable target of product yield is realized. The design of the lower tower plate and the upper filler is adopted, the advantages of high efficiency of the tower plate and uniform runoff of the filler are complemented, and the aim of considering both absorption efficiency and absorption rate is fulfilled; the combined filler adopts the design that different warp directions are alternately arranged and the bulk density is gradually reduced from top to bottom, thereby being beneficial to realizing radial flow uniform distribution, reducing reaction gas and improving absorption efficiency.

Drawings

FIG. 1 is a schematic view of the inside of a tower according to the present invention;

FIG. 2 is a side cross-sectional view of the separator of the present invention;

FIG. 3 is a diagram of a splitter vane distribution structure of the present invention;

FIG. 4 is a block diagram of a sprinkler according to the present invention;

FIG. 5 is a block diagram of a distributor of the present invention;

fig. 6 is a view showing the structure of the liquid-receiving screen of the present invention.

In the figure: 1. a tower body; 11. a cylinder I; 111. a foam breaking net; 12. a cylinder II; 121. a cylinder II is filled; 122. a cylinder II column plate; 13. a cylinder III; 131. a cylinder III is filled; 14. a cylinder IV; 141. a cylinder IV filler; 15. a cylinder V; 151. a cylinder V packing; 152. reinforcing the cylinder; 16. an upper end enclosure; 17. a gas phase outlet pipe; 2. a gas phase inlet pipe; 3. a separator; 31. a bracket; 32. a fan blade seat; 33. a fan blade; 4. a sprayer; 41. a liquid storage tray; 42. a liquid inlet pipe; 43. an outer catheter; 44. an inner catheter; 5. a distributor; 51. a top liquid receiving tank rod; 52. a medium liquid receiving tank rod; 53. a bottom liquid receiving tank rod; 54. a connecting rod; 55. a liquid-receiving silk screen; 6. a secondary reflux spray pipe; 7. a main return shower; 8. desalted water spray pipe; 9. a liquid phase outlet pipe.

Detailed Description

For the purpose of making the objects, technical solutions and advantages of the embodiments of the present invention more apparent, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention, and it is apparent that the described embodiments are some embodiments of the present invention, but not all embodiments of the present invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.

A gas-phase quenching circulation absorption tower for preparing acrylic acid by propylene oxidation method is shown in figure 1, and comprises a tower body 1 composed of a plurality of cylinders with different thicknesses, a gas-phase inlet pipe 2 fixedly connected to the lower part of the tower body 1 and used for introducing gas phase, a separator 3 arranged in the gas-phase inlet pipe 2 and used for rotationally separating the gas phase, three sprayers 4 distributed at intervals in the inner cavity of the tower body 1, two distributors 5 distributed at the upper part and the lower part of the tower body 1, a secondary reflux spray pipe 6, a main reflux spray pipe 7 and a desalted water spray pipe 8 respectively fixedly connected with different sprayers 4, and a liquid-phase outlet pipe 9 fixedly connected to the bottom of the tower body 1.

As shown in FIG. 1, the tower body 1 comprises a cylinder I11, a cylinder II 12, a cylinder III 13, a cylinder IV 14 and a cylinder V15, wherein the cylinder I11, the cylinder II 12, the cylinder III 13, the cylinder IV 14 and the cylinder V15 are fixedly connected in a stacked manner from bottom to top, the outer diameter of the cylinder I is 11 at maximum, and the wall thickness is 15-18 mm, preferably 16mm. The outer diameters of the cylinder II 12, the cylinder III 13, the cylinder IV 14 and the cylinder V15 are the same, wherein the wall thickness of the cylinder II 12 is 15-18 mm, preferably 16mm; the wall thickness of the cylinder III 13 is 13-16 mm, preferably 14mm; the wall thickness of the cylinder IV 14 is 10-14 mm, preferably 12mm; the wall thickness of the cylinder V15 is 10 to 14mm, preferably 12mm. Because the lower part of the tower body 1 is a liquid phase gathering area, the corrosion is relatively serious, so that the plate of the cylinder body I11 is thick, and the rest cylinders are made of thinner plates, thereby not only reducing equipment investment, but also keeping the consistency of the whole corrosion degree of the equipment and prolonging the service life of the tower body. The top of the cylinder V15 is fixedly connected with an upper sealing head 16, and the upper sealing head 16 is fixedly connected with a gas phase outlet pipe 17 for guiding the separated gas phase out of the tower body 1, so that the purity of the liquid phase is prevented from being reduced by mixing and liquefying with the liquid phase.

In addition, the outer welding of barrel V15 has strengthened barrel 152, strengthens the annular structure that the barrel 152 was enclosed for the steel sheet, sets up to strengthen the structural strength of barrel 152 mainly used in reinforcing tower body 1 upper portion, makes tower body 1 upper portion be difficult for warping after filling the multilayer packing, and the weight of cooperation packing makes tower body 1 have better anti-wind antidetonation difficult effect of warping simultaneously.

As shown in figure 1, the inner cavity of the tower body 1 at the joint of the cylinder body I11 and the cylinder body II 12 is filled with a foam breaking net 111, the foam breaking net 111 is woven by 0.08-0.30 mm oblate wires, the mesh is preferably 4mm multiplied by 5mm, the upper bevel of the woven net surface is 20-45 degrees, and the corrugated wave with the depth of 5-7 mm is used for primarily eliminating foam rising by gas and liquid, but cannot be completely eliminated, and the foam is further eliminated by repeatedly colliding with the filler on the upper layer.

As shown in fig. 1, a cylinder ii filler 121 is filled in a cylinder ii 12, a cylinder iii filler 131 is filled in a cylinder iii 13, a cylinder iv filler 141 is filled in a cylinder iv 14, and a cylinder v filler 151 is filled in a cylinder v 15, wherein the fillers are one or more selected from stainless steel 304L, stainless steel 316L, orifice plate corrugated filler, calendaring orifice ring filler or silk screen filler, and the inclination angle of the fillers is set between 30 degrees and 60 degrees. The bulk density from the barrel II filler 121 to the barrel V filler 151 is sequentially increased, and the filler heights are sequentially reduced, so that the pressure drop of the filler layer is reduced, the treatment capacity of the filler layer is increased, the reasonable specific absorption surface area is maintained, and the maximum gas phase separation efficiency is ensured. In addition, the inclined surfaces between the two layers of fillers are kept to be discharged relatively so as to keep a zigzag liquid flow channel, prevent the liquid phase runoff from directly discharging downwards, provide a wetting surface for gas phase liquefaction and realize the maximization of absorption efficiency.

As shown in FIG. 1, a plurality of layers of barrel II trays 122 are arranged in the barrel II 12, the barrel II trays 122 are sieve trays, and the aperture ratio is preferably 14%. The column plates are also arranged in the column body I11, wherein the number of the column plates in the column body I11 is preferably 7 layers, the number of the column plates in the column body II is preferably 9 layers, so that a preliminary contact surface of a gas phase and a liquid phase is formed, and the advantage of high liquefying efficiency of the sieve plate column plates is exerted. Specifically, according to an ideal system gas-liquid phase balance equation, an intersection point coordinate calculation formula of a rectifying section operation line and a stripping section operation line, an operation line equation and a q line equation, or by using software Maple and Math CAD software, the number of required theoretical plates is calculated, according to the relation between the number of the plates, the height of the packing and the bulk density, the heights of the packing of various types are determined, and the packing is filled in the tower body 1 according to the sequentially increasing sequence of the bulk density from the packing 121 of the cylinder II to the packing 151 of the cylinder V.

As shown in fig. 1, the gas phase inlet pipe 2 is a T-shaped three-way pipe, the top of the gas phase inlet pipe 2 is fixedly connected with a gas baffle plate, the plate height is preferably the pipe radius, two separators 3 are respectively arranged at two gas inlet pipe openings in the horizontal direction of the gas phase inlet pipe 2, and the other separator 3 is arranged at a gas outlet pipe opening of the gas phase inlet pipe 2 in the vertical direction. The gas phase enters the pipe through the pipe orifices at the two sides of the gas phase inlet pipe 2, is subjected to preliminary rotary separation through the separator 3 in the horizontal direction, and then enters the barrel I11 through the secondary rotary separation through the separator 3 in the vertical direction, so that various molecules in the gas phase are dispersed into the barrel I11 to the greatest extent, a good physical environment is provided for subsequent gas phase full liquefaction, namely, the contact area of the gas phase molecules and liquid is increased, and compared with the method that the gas phase is directly led into the gas phase for liquefaction, the liquefaction amount in the time is improved by 18%, and the obvious efficiency improvement is realized.

Referring to fig. 2 and 3, the separator 3 includes a support 31, a fan blade seat 32 and fan blades 33, wherein the outer edges of the three supports 31 are divergently fixedly connected with the inner wall of the gas inlet pipe 2, the middle parts of the three supports 31 are mutually fixedly connected, the fan blade seat 32 is rotatably connected with the middle parts of the connecting ends of the three supports 31 through a liquid self-lubricating bearing, the three fan blades 33 are annularly fixedly connected with the fan blade seat 32 at intervals through nuts, and the deflection angle of the fan blades 33 is set to be 30-60 degrees. By utilizing the liquid self-lubricating bearing, the liquid condensate in the gas phase and evaporated liquid condensate can be utilized for lubrication, so that the rotation abrasion is reduced, the service life of the separator is prolonged, and the cleanness of the medium is ensured. The deflection angle of the fan blades 33 can be adjusted according to the use condition, wherein 45 degrees are preferable, the fan blades 33 can directly rotate by taking the gas phase pressure entering the pipeline as a power source, no power equipment is additionally arranged, the operation stability of the device is maintained, and gas phase molecules can be dispersed, so that two purposes are achieved.

Referring to fig. 1 and 4, the sprayer 4 comprises a liquid storage disc 41, a liquid inlet pipe 42, an outer liquid guide pipe 43 and an inner liquid guide pipe 44, wherein the main body of the liquid storage disc 41 is of a flat barrel structure, the bottom of the liquid storage disc 41 is hollowed out, the hollowed-out radius is preferably 1/2 of the radius of the bottom of an inner cavity of the liquid storage disc 41, and a conical bottom sealing part is welded at the hollowed-out part; the liquid inlet pipe 42 is fixedly connected to the middle part of the top end of the liquid storage disc 41, the liquid inlet pipe 42 is sized according to the pipe diameter of the conveying pipe, and cone-shaped reducing can also be adopted; the outer liquid guide tube 43 is welded on two sides of the bottom of the liquid storage disc 41, and a plurality of drain holes are added at the bottom of the liquid guide tube according to the length of the outer liquid guide tube 43 so as to keep liquid spraying uniformity; the inner liquid guide tube 44 is welded on the conical back cover of the liquid storage disc 41, preferably 8 branch tubes, the tube wall extends out of the bottom of the liquid storage disc 41 along the inclined direction of the conical inner wall, and the height of an opening of the inner liquid guide tube 44 on the conical inner wall is half of the tube diameter higher than the height of the inner hole of the outer liquid guide tube 43, so that the flow rate of the central liquid is prevented from being large, and the flow rate of the peripheral liquid is small. Its advantages are balanced flow, big open hole and low resistance.

With reference to fig. 1 and 5, the two distributors 5 are respectively disposed in the cylinder i 11 and the cylinder v 15, the distributor 5 in the cylinder i 11 is disposed between the two sprayers 4, and the distributor 5 in the cylinder v 15 is disposed below the sprayers 4 in the cylinder v 15. The distributor 5 comprises a top liquid receiving tank rod 51, a middle liquid receiving tank rod 52, a bottom liquid receiving tank rod 53 and connecting rods 54, wherein the top liquid receiving tank rod 51, the middle liquid receiving tank rod 52 and the bottom liquid receiving tank rod 53 are all V-shaped rods and distributed at intervals from top to bottom, a plurality of connecting rods 54 are fixedly connected between the top liquid receiving tank rod 51, the middle liquid receiving tank rod 52 and the bottom liquid receiving tank rod 53 at intervals to support the top liquid receiving tank rod 51, the middle liquid receiving tank rod 52 and the bottom liquid receiving tank rod 53, a plurality of liquid receiving holes are formed in tank edges of the top liquid receiving tank rod 51, the middle liquid receiving tank rod 52 and the bottom liquid receiving tank rod 53, and two residual liquid discharge holes are formed in bottoms of the top liquid receiving tank rod 51 and the bottom liquid receiving tank rod 53. The liquid receiving holes are in unsaturated design, a certain liquid overflow amount at the side of the liquid receiving groove is reserved, and only two residual liquid discharge holes are reserved at the bottom of the liquid receiving groove, so that the liquid flow area is increased conveniently. With reference to fig. 6, a liquid receiving screen 55 in the shape of a disk is arranged below the bottom liquid receiving tank rod 53, the liquid receiving screen 55 is preferably made of stainless steel, and the steel wire adopts a surface treatment process, so that the liquid flow is smoother and more uniform.

With reference to fig. 1 and 4, two sprayers 4 are distributed in the cylinder i 11 at intervals along the vertical direction, and the secondary reflux spray pipe 6 is fixedly connected with a liquid inlet pipe 42 on the sprayer 4 with a low height. The main reflux spray pipe 7 is fixedly connected with a liquid inlet pipe 42 on the sprayer 4 with high height. The secondary reflux spray pipe 6 and the main reflux spray pipe 7 are both communicated with a liquid phase outlet pipe 9, and the liquid phase of the liquid phase outlet pipe 9 is fed into a light component removing section or a acetic acid removing section for continuous distillation and separation besides the liquid level maintained by reflux. A sprayer 4 is also arranged in the cylinder V15, a desalted water spray pipe 8 is fixedly connected to the sprayer 4 in the cylinder V15, and desalted water is introduced into the desalted water spray pipe 8. The spray liquid is pumped to the main reflux spray pipe 7 and the secondary reflux spray pipe 6 through the liquid phase outlet pipe 9, and is subjected to reflux spray through the tower top desalted water and the tower bottom liquid, so that the gas phase is rapidly cooled, and preliminary absorption and liquefaction are carried out. The gas phase acrylic acid enters the tower body 1 through the gas phase inlet pipe 2, the gas phase is repeatedly absorbed by water through the tower plates and the packing layers in the ascending process, and is collected into a liquid phase at the tower bottom, and air components such as oxygen, nitrogen and the like which are insoluble in water and the reaction gas phase are discharged out of the tower through the gas phase outlet pipe 17 to be repeatedly reacted or enter the tail gas treatment device.

As shown in fig. 1, the tower body 1 is further provided with a plurality of temperature sensors, pressure sensors and a liquid level meter, wherein the temperature sensors are connected with a total control room PLC distributed control system, and send control signals to an automatic flowmeter, an electromagnetic control valve and other devices according to transmission temperature data to control the flow of the secondary reflux spray pipe 6, the main reflux spray pipe 7 and the desalted water spray pipe 8 and the output flow of the liquid phase outlet pipe 9, so that the temperature of the whole absorption tower is maintained to meet the operation requirement. The pressure sensor is connected with the total control room PLC distributed control system, and sends control signals to the automatic flowmeter, the electromagnetic control valve and other devices according to the transmission pressure data, so as to control the flow of the secondary reflux spray pipe 6, the main reflux spray pipe 7 and the desalted water spray pipe 8 and the delivery flow of the liquid phase outlet pipe 9, and maintain the pressure of the whole absorption tower to meet the operation requirement. The liquid level meter is divided into a field liquid level meter and a remote transmission liquid level meter, the field liquid level meter is used for field inspection of an operator, the remote transmission liquid level meter is connected with a total control room PLC distributed control system, control signals are sent to devices such as an automatic flowmeter, an electromagnetic control valve and the like according to transmission liquid level data, the flow of the secondary reflux spray pipe 6, the main reflux spray pipe 7 and the desalted water spray pipe 8 and the delivery flow of the liquid phase outlet pipe 9 are controlled, and the liquid level of the whole absorption tower kettle is maintained to meet the operation requirement.

The invention also provides a process flow for purifying acrylic acid, which comprises the following specific steps:

closing the gas phase inlet pipe 2 and the liquid phase outlet pipe 9, enabling desalted water to enter the tower from the desalted water spray pipe 8 and the sprayer 4 below the desalted water spray pipe 8, opening the liquid phase reflux port of the liquid phase outlet pipe 9 and the inlet of the main reflux spray pipe 7 when the desalted water reaches the reflux pump starting condition, and starting the reflux pump; after the reflux is stable, the gas phase inlet pipe 2 is gradually opened to feed air, desalted water is repeatedly subjected to mass transfer and heat transfer through the multi-layer packing layers, the tower plates and the lower gas phase, so that the gas phase liquefaction is realized by reducing the temperature of the reaction gas phase, the gas phase components of the acrylic acid liquid are absorbed to the maximum extent, the liquid phase is collected in the tower kettle, and air components such as oxygen, nitrogen and the like which are insoluble in water and the reaction gas phase are discharged out of the tower through the gas phase outlet pipe 17 to be repeatedly reacted or enter the tail gas treatment device. While increasing the gas phase flow rate, the secondary reflux shower pipe 6 is opened until the gas phase increases to the normal design flow rate.

When the liquid level of the tower kettle reaches the upper limit of the liquid level, a discharge port of a liquid phase outlet pipe 9 is opened, liquid is supplied to the light component removing section or the acetic acid removing section, and the reaction liquid is distilled and separated.

When the temperature and the pressure rise, the spraying amount of the desalted water spraying pipe 8 can be increased, or the reflux amount of the secondary reflux spraying pipe 6 and the main reflux spraying pipe 7 can be increased, if the liquid level is unstable, the operation method can be compromised, and the flow of the desalted water spraying pipe 8, the reflux amount of the secondary reflux spraying pipe 6 and the reflux amount of the main reflux spraying pipe 7 can be increased in a small extent. If the temperature and the pressure are reduced, the reverse operation is performed. The liquid level can be adjusted by increasing or decreasing the discharge amount of the liquid phase outlet pipe 9, or by decreasing or increasing the spray amount of the desalted water spray pipe 8.

In summary, according to the invention, through adopting the barrel designs with different thicknesses, the lower tower barrel plate is thicker and more corrosion-resistant, and the upper part is thinner, so that the equipment investment is reduced, the consistency of the overall corrosion degree of the equipment is maintained, and the service life of the tower body is prolonged. The adopted separator 4 takes the reaction gas pressure as a power source, and the fan blades 33 of the separator 3 adopt an adjustable structure, so that the gas-liquid separation effect is enhanced, and the energy consumption is also saved; the distributor 3 is circularly and uniformly distributed, so that the absorption efficiency of acrylic acid is enhanced, and the controllable target of the product yield is realized. In addition, the design of a lower column plate and an upper packing is adopted, the advantages of high efficiency of the column plate and uniform runoff of the packing are complemented, and the aim of considering both absorption efficiency and absorption rate is fulfilled; and the tower filler adopts different warp direction alternate arrangement and the design that the bulk density gradually reduces from top to bottom, thereby being beneficial to realizing radial flow uniform distribution, reducing reaction gas and improving absorption efficiency. The sprayer 4 and the distributor 5 are designed by adopting offset holes, and a liquid receiving screen 55 is added at the lower part of the distributor 5, so that the spray liquid is uniformly distributed, and the imbalance problem that the pressure of the middle liquid flow is high and the pressure of the edge liquid flow is small is solved. And the remote automatic control is realized by being provided with remote temperature, pressure and liquid level transmission equipment and being connected with a total control room PLC distributed control system, and sending control signals to devices such as an automatic flowmeter, an electromagnetic control valve and the like according to transmission data, thereby not only improving the yield but also reducing the labor cost.

Finally, it should be noted that: the above embodiments are only for illustrating the technical solution of the present invention, and are not limiting; although the invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A gas-phase quenching circulation absorption tower for preparing acrylic acid by propylene oxidation is characterized in that: the device comprises a tower body (1) composed of a plurality of cylinders with different thicknesses, a gas phase inlet pipe (2) fixedly connected to the lower part of the tower body (1) and used for introducing gas phase, a separator (3) arranged in the gas phase inlet pipe (2) and used for rotationally separating the gas phase, a plurality of sprayers (4) distributed in the inner cavity of the tower body (1) at intervals, and two distributors (5) distributed at the upper part and the lower part of the tower body (1), wherein different cylinders are internally provided with packing with different densities and trays with different layers, and the desalted water passes through the packing, the trays and the distributors (5) downwards through the top of the tower body (1) and the gas phase introduced into the tower body (1) through the sprayers (4) which are partially distributed near the gas phase inlet pipe (2) to carry out repeated mass transfer and heat transfer; the number of the separators (3) is three, the gas phase inlet pipe (2) is a T-shaped three-way pipe, two separators (3) are respectively arranged at two air inlet pipe openings in the horizontal direction of the gas phase inlet pipe (2), and the other separator (3) is arranged at an air outlet pipe opening of the gas phase inlet pipe (2) in the vertical direction; the separator (3) comprises a bracket (31), a fan blade seat (32) and fan blades (33), wherein the bracket (31) is fixedly connected with the inner wall of the gas-phase inlet pipe (2), the fan blade seat (32) is rotationally connected to the middle part of the bracket (31) through a liquid self-lubricating bearing, a plurality of fan blades (33) are fixedly connected to the fan blade seat (32) at annular intervals, and the deflection angle of the fan blades (33) is set to be 30-60 degrees;

the distributor (5) comprises a top liquid receiving tank rod (51), a middle liquid receiving tank rod (52), a bottom liquid receiving tank rod (53) and connecting rods (54), wherein the top liquid receiving tank rod (51), the middle liquid receiving tank rod (52) and the bottom liquid receiving tank rod (53) are V-shaped rods and distributed at intervals from top to bottom, a plurality of connecting rods (54) are fixedly connected between the top liquid receiving tank rod (51), the middle liquid receiving tank rod (52) and the bottom liquid receiving tank rod (53) at intervals so as to support the top liquid receiving tank rod (51), the middle liquid receiving tank rod (52) and the bottom liquid receiving tank rod (53), a plurality of liquid receiving holes are formed in tank edges of the top liquid receiving tank rod (51), the middle liquid receiving tank rod (52) and the bottom liquid receiving tank rod (53), and two residual liquid discharging holes are formed in the bottoms of the top liquid receiving tank rod (51) and the bottom liquid receiving tank rod (53); the two distributors (5) are respectively arranged in the cylinder I (11) and the cylinder V (15), the distributor (5) in the cylinder I (11) is positioned between the two sprayers (4), and the distributor (5) in the cylinder V (15) is positioned below the sprayers (4) in the cylinder V (15).

2. The gas-phase quenching recycle absorption tower for preparing acrylic acid by propylene oxidation method according to claim 1, wherein the gas-phase quenching recycle absorption tower is characterized in that: the tower body (1) comprises a cylinder body I (11), a cylinder body II (12), a cylinder body III (13), a cylinder body IV (14) and a cylinder body V (15), wherein the cylinder body I (11), the cylinder body II (12), the cylinder body III (13), the cylinder body IV (14) and the cylinder body V (15) are fixedly connected in a stacked manner from bottom to top, the outer diameter of the cylinder body I (11) is the largest, and the outer diameters of the cylinder body II (12), the cylinder body III (13), the cylinder body IV (14) and the cylinder body V (15) are the same.

3. The gas-phase quenching recycle absorption tower for preparing acrylic acid by propylene oxidation method according to claim 2, wherein the gas-phase quenching recycle absorption tower is characterized in that: the wall thickness of the cylinder I (11) is 15-18 mm, the wall thickness of the cylinder II (12) is 15-18 mm, the wall thickness of the cylinder III (13) is 13-16 mm, the wall thickness of the cylinder IV (14) is 10-14 mm, and the wall thickness of the cylinder V (15) is 10-14 mm.

4. A gas-phase quenching recycle absorption tower for preparing acrylic acid by propylene oxidation method according to claim 3, wherein the gas-phase quenching recycle absorption tower is characterized in that: the outside of the cylinder V (15) is welded with a reinforcing cylinder (152), and the reinforcing cylinder (152) is of an annular structure surrounded by steel plates.

5. The gas-phase quenching recycle absorption tower for preparing acrylic acid by propylene oxidation method according to claim 4, wherein the gas-phase quenching recycle absorption tower is characterized in that: barrel II (12) is filled with barrel II filler (121), barrel III (13) is filled with barrel III filler (131), barrel IV (14) is filled with barrel IV filler (141), barrel V (15) is filled with barrel V filler (151), wherein the bulk density from barrel II filler (121) to barrel V filler (151) is sequentially increased, and the filler height is sequentially reduced.

6. The gas-phase quenching recycle absorption tower for preparing acrylic acid by propylene oxidation method according to claim 5, wherein the gas-phase quenching recycle absorption tower is characterized in that: the filler is one or more of stainless steel 304L, stainless steel 316L, pore plate corrugated filler, calendaring pore ring filler or silk screen filler, and the inclination angle of the filler is between 30 and 60 degrees.

7. The gas-phase quenching recycle absorption tower for preparing acrylic acid by propylene oxidation method according to claim 6, wherein the gas-phase quenching recycle absorption tower is characterized in that: a foam breaking net (111) is filled between the cylinder I (11) and the cylinder II (12), oblate wires with the foam breaking net (111) of 0.08-0.30 mm are woven, and the net surface of the foam breaking net (111) is pressed with waves with the oblique angle of 20-45 degrees and the depth of 5-7 mm.

8. The gas-phase quenching recycle absorption tower for preparing acrylic acid by propylene oxidation method according to claim 2, wherein the gas-phase quenching recycle absorption tower is characterized in that: the two sprayers (4) are distributed in the cylinder I (11) at intervals along the vertical direction, the sprayer (4) with low height is fixedly connected with a secondary reflux spray pipe (6), and the sprayer (4) with high height is fixedly connected with a main reflux spray pipe (7); the bottom of the cylinder I (11) is fixedly connected with a liquid phase outlet pipe (9), and the secondary reflux spray pipe (6) and the main reflux spray pipe (7) are communicated with the liquid phase outlet pipe (9); a sprayer (4) is also arranged in the cylinder body V (15), a desalted water spray pipe (8) is fixedly connected to the sprayer (4) in the cylinder body V (15), and desalted water is introduced into the desalted water spray pipe (8).