CN108043061B

CN108043061B - Catalytic distillation column plate capable of replacing catalyst on line

Info

Publication number: CN108043061B
Application number: CN201711416080.9A
Authority: CN
Inventors: 何岩; 王中华; 赵一鸣; 刘俊贤; 宋明炎; 乔小飞; 黎源
Original assignee: Wanhua Chemical Group Co Ltd
Current assignee: Wanhua Chemical Group Co Ltd
Priority date: 2017-12-25
Filing date: 2017-12-25
Publication date: 2021-03-09
Anticipated expiration: 2037-12-25
Also published as: CN108043061A

Abstract

The invention discloses a catalytic rectification plate tower capable of replacing a catalyst on line, which comprises a tower tray, a plurality of gas-liquid contact elements and a plurality of suspended downcomers which are arranged on the tower tray, a suspended liquid receiving disc positioned below the suspended downcomers and a catalyst loading and unloading hole used for loading and unloading the catalyst on the tower tray, wherein the free space enclosed by the suspended downcomers, the gas-liquid contact elements, the tower tray and the tower wall is a catalyst loading area, the catalyst is scattered and stacked in the catalyst loading area, and the suspended downcomers comprise inner downcomers penetrating through the tower tray and outer flow guide covers covering the upper part of the bottom of the tower tray of the inner downcomers. The tower plate directly bulks on the tower tray without complex packaging of the catalyst, can realize on-line catalyst replacement under the condition that the device is not stopped, and has uniform catalyst distribution, reduced tower tray pressure and high rectification efficiency. Meanwhile, expensive catalyst packaging materials and fillers are omitted, and the cost can be obviously reduced.

Description

Catalytic distillation column plate capable of replacing catalyst on line

Technical Field

The invention relates to novel equipment for a catalytic rectification process, in particular to a catalytic rectification tower plate capable of replacing a catalyst on line.

Technical Field

In the traditional chemical production process, reaction raw materials are generally reacted in a reactor, and then reaction products enter a downstream separation process for separation and purification. With the continuous progress of chemical industrial technology, the conventional chemical production process of traditional reaction and separation increasingly shows the defects of complex flow, large equipment investment, high energy consumption and the like, and various process strengthening new technologies are continuously emerged. The reaction rectification technology couples reaction and rectification separation means together, greatly simplifies equipment and flow, can obviously improve the yield of an equilibrium reaction and a parallel or serial complex reaction system, effectively utilizes reaction heat, saves energy and reduces consumption, and is rapidly developed in a plurality of industrial production fields such as esterification, etherification, hydrolysis, hydrogenation and the like. However, the homogeneous catalyst and the reaction system adopted in the traditional reactive distillation are difficult to separate, the acidic and basic catalysts widely adopted seriously corrode equipment, and the equipment investment and the three-waste treatment are still high in cost. Therefore, a catalytic distillation technology using a heterogeneous catalyst is produced. Due to the adoption of the heterogeneous catalyst, the problems of catalyst separation and equipment corrosion are well solved, and the device shows great technical and economic advantages along with the successful industrial application of devices for MTBE synthesis, acetic ester hydrolysis and the like.

One of the key technical links of the catalytic distillation process is the filling mode of the heterogeneous catalyst, so that various different catalyst filling structures are generated. For example, U.S. Pat. No. 3434534 discloses a technology of loading catalyst in the downcomer of a catalytic distillation tray, but the loading of catalyst in the downcomer is limited, and the catalyst loading in the downcomer is liable to affect the downcomer capacity, so that the industrial implementation has a great limitation. U.S. patent publication No. 4471154 discloses that the catalyst is packed in a shaped bag and arranged on a catalytic distillation tray in a certain manner, which occupies a large tray space and has poor distillation efficiency; the filled bag increases the mass transfer resistance of the reaction liquid and the catalyst and also limits the reaction effect. The U.S. patent publication No. 4,4215011 discloses that the catalyst is filled in a special bag made of glass fiber cloth, and is alternately rolled with a silk screen into a roll shape, and is installed at the reaction section of a catalyst rectifying tower, the silk screen provides a gas channel and a rectifying space, the mass transfer resistance is reduced by the thinner glass fiber bag, the glass fiber silk screen packing technology of the type is successfully used for industrial devices such as MTBE and the like, and the glass fiber silk screen packing technology is the most mature and widely applied catalytic rectifying internal part structure at present. Subsequently, different manufacturers have developed on this basis, such as the technique of wire-corrugated packing, but this is not fundamentally different from the technique disclosed in patent US 4215011.

Although the catalytic rectification internal part scheme represented by the technology disclosed in the U.S. Pat. No. 4,4215011 has the advantages of high rectification efficiency, wide system applicability and the like, the catalytic rectification internal part scheme also has the outstanding problems of complex equipment structure, limited catalyst loading amount, difficult catalyst loading and unloading, high use cost of catalytic rectification components, large resistance of reaction liquid spreading to the surface of the catalyst and product diffusion to a liquid phase body due to packing, reaction efficiency reduction and the like. In response to these problems, the skilled person also tries to develop a new catalyst packing scheme, for example, chinese published patent CN88109705 discloses that in the reaction section of the column, catalytic reaction trays and rectification trays are alternately arranged, and the catalyst on the reaction trays adopts a bulk packing manner similar to a fixed bed, and has no rectification function. However, in the scheme, the reaction and the rectification are placed on different trays, so that the reaction and the separation cannot occur simultaneously, the mutual promotion effect of the catalysis and the rectification is reduced, and the application range of the catalytic distillation is limited. Chinese published patent CN93101420 discloses a sieve tray with a screen laid on the tray, and a catalyst is scattered on the tray. Although the tray has a simple structure, the sieve plate tray has limited liquid holdup, uneven catalyst distribution and larger catalyst abrasion and leakage, and influences plate efficiency and reaction effect. Chinese patent publication CN01114953 discloses a catalytic rectification tower tray with gas risers, the catalyst is scattered and piled at the bottom of the tower tray, the gas risers are higher than the catalyst, the gas riser is equipped with gas-liquid mass transfer elements such as float valve, bubble cap, etc. on the upper part of the gas riser, because the liquid on the tower tray flows to one direction in the horizontal direction, the catalyst is distributed unevenly, the rectification efficiency is not high, the reaction liquid can not pass through the catalyst bed, the liquid phase displacement is slow, the problems of detention zone and dead zone exist, the reaction effect is affected. Particularly, for a catalytic rectification system with complicated reactions such as serial or parallel reactions, the reaction yield of the tray is poor.

Disclosure of Invention

The invention aims to provide a novel catalytic distillation tower tray, which does not need to carry out complex packaging on a catalyst, is directly and bulk-packed on the tower tray, can realize online catalyst replacement under the condition that the device is not stopped, has uniform catalyst distribution, uniform liquid phase flow, full contact with the catalyst, reduced tower tray pressure and high distillation efficiency. Meanwhile, expensive catalyst packaging materials and fillers are omitted, and the cost can be obviously reduced.

In order to achieve the above purpose, the technical scheme of the invention is as follows:

a catalytic rectification tower plate capable of replacing catalyst on line comprises a tower tray, a plurality of gas-liquid contact elements and a plurality of suspended downcomers arranged on the tower tray, a suspended liquid receiving tray positioned below the suspended downcomers and a catalyst loading and unloading hole arranged on the tower wall and used for loading and unloading the catalyst on the tower tray, wherein the suspended downcomers comprise inner downcomers penetrating through the tower tray and outer flow guide covers covering the upper parts of the bottom of the tower tray of the inner downcomers, free space surrounded by the suspended downcomers, the gas-liquid contact elements, the tower tray and the tower wall is a catalyst loading area, and the catalyst is scattered and stacked in the catalyst loading area,

the bottom of the outer diversion cover is provided with a liquid suction port, the liquid suction port is provided with a screen, and the liquid phase enters an annular gap between the inner downcomer and the outer diversion cover from the liquid suction port and further enters the inner downcomer.

Preferably, the gas-liquid contacting element comprises a riser mounted on the tray and a spray cap mounted on the upper portion of the riser, the lower end and/or lower portion of the spray cap being provided with gas spray holes (the holes herein comprise slots or grooves) at a position below the liquid surface. A deflector is preferably arranged beside the gas injection hole.

Preferably, the plurality of suspended downcomers are respectively and uniformly distributed on the tray, and the suspended downcomers and the gas-liquid contact elements are mutually and alternately distributed on the tray.

The catalyst loading and unloading holes for loading and unloading the catalyst on the trays are preferably arranged at a height (side-cut catalyst loading and unloading opening) between the tray and the liquid level on the corresponding column wall of each layer of trays.

The pore diameter of the screen at the liquid suction port is determined according to the size of catalyst particles, for example, when the size of an ion exchange resin catalyst for TBA dehydration is 0.3 to 1.5mm, the pore diameter of the screen is generally 0.2mm or less, for example, 0.05 to 1 mm.

The vertical distance from the lower end of the ejection cap to the tray is about 5-95%, preferably 10-50% of the height of the liquid layer on the tray. The gas-liquid contact element is provided with a gas riser which is 20-1000 mm higher than the bottommost end of the tower tray; the gas lift pipe is cylindrical, elliptic cylinder or trapezoid or taper with the section narrowing upwards, and the gas generating pipe is preferably cylindrical or elliptic cylinder.

The cross section of the injection cap can be circular, oval or trapezoidal or conical with the cross section narrowing upwards, and the cross section is preferably circular or oval.

The inner downcomers and the outer guide cover can be round, square, rectangular or strip-shaped, preferably cylindrical downcomers, and the number of the suspended downcomers of each layer of the tower tray is 2-200, preferably 5-20. Preferably selecting a circular or strip-shaped downcomer, and when a strip-shaped inner downcomer is selected, the length-width ratio of the inner downcomer is 1-500, preferably 5-50; the inner downcomers of the upper layer of tower tray and the lower layer of tower tray are not overlapped in the vertical direction, and the downcomers of the adjacent two layers of tower trays rotate by 0-90 degrees in the horizontal direction preferably.

The openings in the spray cap are not uniform; when the cross section of the spray cap in plan view is circular or quasi-circular (such as oval), preferably, more holes are formed on one side of a connecting line between the midpoint of the tray and the geometric center of the spray cap, and no holes or few holes are formed on the other side; preferably, one side is perforated and one side is not perforated, so that the gas phase has a circumferential pushing force against the liquid phase, pushing the liquid phase to have a circumferential flow on the tray, ideally, no or few perforations are provided in the direction opposite to the liquid phase flow. The direction of the flow deflector beside the gas injection hole of the injection cap cover forms an angle of 0-90 degrees with a connecting line of the middle point of the tower tray and the geometric center of the injection cap cover (or the included angle formed by the flow deflector and a tangent line extending out of the injection cap cover of the flow deflector is preferably an acute angle), and forms an angle of 0-45 degrees with the horizontal flow direction of the liquid, and the angle of 0 degree is completely consistent with the flow direction of the liquid phase. Smaller included angles provide better propulsion of the liquid phase, and >90 ° means that jetting against the direction of liquid flow, and reverse turbulence of the liquid phase is undesirable.

The lower end of the suspended downcomer is provided with a suspended liquid receiving disc, and the shape of the liquid receiving disc corresponds to that of the downcomer and can be circular, square, rectangular or strip-shaped. The lower end of the downcomer is 50-200 mm away from the liquid receiving disc, the width of the liquid receiving disc is 10-200 mm larger than that of the downcomer, and a tooth-shaped overflow weir is preferably adopted in the suspended liquid receiving disc.

The number of side line openings of each layer of tower tray is 2N (N is 1-10), and guide vanes are arranged on the tower tray and at the positions, 50-500 mm from the side line openings, of the tower tray towards the inner side of the tower tray, and are used for facilitating the uniform distribution of a liquid phase driven catalyst when the catalyst is replaced.

A screen is arranged between one of the side openings of each layer of trays and the external catalyst replacement system.

The invention further relates to the application of the catalytic distillation tower plate in a process for preparing isobutene by catalytic distillation of tert-butyl alcohol.

The novel catalytic rectification tower plate disclosed by the invention has the advantages that the granular catalyst is scattered on the tower tray when in use, so that the problems of large mass transfer resistance, inconvenience in disassembly, high manufacturing cost and the like caused by the need of packaging the catalyst in the traditional technology are completely solved. Through the arrangement of the liquid descending rolling guide pipe, a reactant liquid phase flows through a catalyst bed layer from top to bottom to react, so that the problems of insufficient contact between the liquid phase and the catalyst or the existence of detention, dead zones and the like are fundamentally avoided.

Preferably, the gas-liquid contact element is a spray cap installed on the upper part of the riser pipe of the tray, and the riser pipe is adopted with a special reaction speed which is not fast and is suitable for reactions needing larger residence, such as esterification of alcohol and acid, dehydration reaction of alcohol and the like. Meanwhile, the filling amount of the catalyst can be obviously higher than that of the existing packing filling scheme; the height of the riser can be adjusted in a larger range, and the riser can provide a residence time which is wider than that of a traditional tray. In practical application, the tray can be used for a process for preparing isobutene by catalytic distillation of tert-butyl alcohol, and the adopted catalyst is sulfonic acid type ion exchange resin.

According to the novel catalytic rectification tower tray, the catalyst is scattered on the tower tray, is positioned between the gas-liquid contact element and the downcomer and is uniformly distributed; the evenly distributed suspended downcomers enable liquid flowing down from the upper tower tray to uniformly impact reaction liquid at the lower layer, and promote locally uneven catalyst to tend to be evenly distributed. The uniform arrangement of a plurality of suspended downcomers also ensures that the flowing distance of the liquid phase from the upper tray to the lower overflow pipe is the same, so that the flowing of the liquid phase is more uniform, and the system with continuous and parallel complex reactions has the great benefits of narrow retention time distribution and high yield as much as possible.

Because the invention adopts the catalyst which is piled in bulk, the outer layer is not bound by a wrapping material, the diffusion mass transfer resistance between the catalyst and the liquid phase reaction raw material is obviously reduced, the reaction efficiency can be improved, the processing capacity of the equipment is increased, the defect of packing the catalytic rectification component is fundamentally avoided, and the possibility of replacing the catalyst without stopping is provided. The catalyst can be carried to a catalyst replacing system outside a tower tray by utilizing the flow of liquid under the condition of no stopping by matching with a side line opening and an external catalyst replacing system which are arranged on the wall of the tower in pairs, and the separation of the catalyst and circulating liquid can be realized by virtue of a screen in the middle of the side line opening and the replacing system, so that the catalyst can be dismounted without stopping.

When the new catalyst is replaced, the reverse flow is adopted, the liquid phase flow is utilized to supplement the new catalyst to the tray, the uniform distribution of the catalyst on the tray can be realized by virtue of a flow guide facility at an inlet of the lateral line opening, and the separation between the new catalyst and the circulating liquid can be realized by utilizing the lateral line opening and a screen in the middle of the replacement system, so that the online filling of the new catalyst is realized. The newly filled catalyst, even if there is local unevenness in the initial stage, is impacted by the overflow liquid phase of the upper multi-downcomer, and the liquid phase on the tray is disturbed, and can gradually tend to the self-adaptive uniform distribution of the catalyst.

In addition, as mentioned above, one of the technical problems of the conventional bulk catalyst is that a liquid phase cannot smoothly pass through a catalyst bed layer, so that the utilization rate of the catalyst is reduced, and meanwhile, a liquid phase is obviously retained or even dead zone in the catalyst bed layer, which seriously affects the rectification and reaction effects. According to the catalytic distillation tower tray, the flow guide outer pipe is arranged outside the downcomer pipe, the liquid suction port is arranged at the lower end of the outer pipe, and liquid passes through the catalyst bed layer from top to bottom and then enters the downcomer, so that the full flowing and contact of the liquid and the catalyst bed layer are guaranteed essentially, and stagnation and dead zones are avoided.

Another significant problem of the conventional tray is that the liquid phase on the tray generally flows from one side to the other side, and a significant liquid level gradient is caused by the resistance of a gas-liquid contact element and the like in the direction of a flow channel, so that the efficiency of the tray is seriously affected, and the catalyst is concentrated along one side of the flow direction to cause uneven distribution of the catalyst, so that the rectification and reaction effects are further deteriorated. The design of uneven open holes and the design of the flow deflector are technical keys in the invention, the invention preferably has uneven open holes on the spraying cap, and the invention preferably has more open holes on one side of a connecting line between the midpoint of the tray and the geometric center of the spraying cap and has no open holes or less open holes on the other side; preferably, one side is open and one side is not open. The direction of the backflow sheet beside the air outlet hole or the groove of the spraying cap cover forms an angle of 0-90 degrees with a connecting line between the middle point of the tower tray and the geometric center of the spraying cap cover, and forms an angle of 0-45 degrees with the horizontal flow direction of the liquid. The arrangement of the air outlet hole and the flow deflector of the jet cap cover ensures that the tower tray generates annular driving force to liquid phase to push the liquid on the tower tray to flow annularly, thereby fundamentally solving the problems of uneven liquid level gradient and catalyst distribution along with the liquid phase flow. Meanwhile, the design of the annular driving force improves the turbulence and the updating rate of the liquid phase on the tray, and the mass transfer efficiency of the tray is higher than that of the conventional tray in actual operation. The inventor actually tries to process the opening of the spray cap and the guide vane, and the guide vane with the required size and angle can be easily obtained by common processing means such as welding and stamping, as shown in fig. 4 and 5.

The shape of the elements on the trays is also important, since optimizing the flow of the liquid phase on the trays is one of the objects of the present invention. The air rising pipe is cylindrical, elliptic cylindrical or trapezoidal or conical with the section gradually narrowing upwards, and preferably, the air generating pipe is cylindrical or elliptic cylindrical; the spray cap is circular or elliptical in cross section or trapezoidal or conical in cross section which narrows upwards, preferably circular or elliptical in cross section. The optimization of the element shape further reduces the flow resistance and liquid level gradient of the liquid phase, optimizes the flow field and is also beneficial to improving the mass transfer and reaction efficiency.

According to the catalytic rectification scheme of the catalyst bulk reactor, the outer packing materials and the filler are abandoned fundamentally, so that the cost of the internal parts is greatly reduced, the cost of the catalyst can be reduced by 40-80% under the working condition that some catalysts need to be replaced frequently, and the economic benefit is remarkable. The catalyst is replaced without stopping, so that the method has important significance for long-period operation of large petrochemical or fine chemical devices, reduction of stopping times, reduction of material loss and three wastes, and has remarkable technical and economic advantages.

Drawings

FIG. 1 is a schematic plan view of a catalytic distillation tray of the present invention; 1-tray, 2-riser, 3-injection cap, 4-jet hole, 5-inner downcomer, 6-outer dome, 7-screen, 8-catalyst loading and unloading hole, and 9-suspended liquid receiving disc;

FIG. 2 is a schematic top view of a tray element layout wherein 3-spray caps, 6-downcomers, 8-catalyst loading and unloading ports, and 10-baffles;

FIG. 3 is a schematic view of the jet cap opening and deflector arrangement, wherein 3-jet cap, 4-jet holes;

fig. 4 is a drawing showing the effect of the punching process of the guide vane of the spray cap, in which 19 is the guide vane;

FIG. 5 is a diagram of the welding effect of the flow deflector of the spray cap;

FIG. 6 is a schematic diagram of the catalyst on-line replacement system, wherein 11-catalyst replacement tube, 12-screen, 13-removal flange, 14-pump, 15-catalyst replacement outer tube.

FIG. 7 is a schematic diagram of catalytic distillation of TBA dehydration, wherein 16-rectification section, 17-reaction section, and 18-stripping section.

Detailed Description

The following describes embodiments of the present invention in further detail with reference to the accompanying drawings.

Tray example 1

As shown in fig. 1 to 5, a catalytic distillation tray capable of replacing a catalyst on line comprises a tray 1, a plurality of gas-liquid contact elements and a plurality of suspended downcomers arranged on the tray, a suspended receiving tray 9 positioned below the suspended downcomers, and a catalyst loading and unloading hole 8 for loading and unloading the catalyst on the tray, wherein the suspended downcomers comprise an inner downcomer 5 (e.g. 5 with a diameter of 65mm) penetrating through the tray and an outer draft shield 6 covering the upper part of the bottom of the tray of the inner downcomer, the gas-liquid contact elements comprise a riser 2 arranged on the tray and a spray cap 3 (e.g. 40 with a diameter of 50mm) arranged on the upper part of the riser, and the lower end and/or the lower part of the spray cap 3 is provided with a gas spray hole 4 at a position below the liquid surface. A flow deflector 19 is arranged beside the gas jet hole. The free space enclosed by the suspended downcomer comprising the inner downcomer 5 and the outer flow guide cover 6, the gas-liquid contact element comprising the gas riser 2 and the injection cap cover 3, the tower tray 1 and the tower wall is a catalyst filling area, the catalyst is scattered in the catalyst filling area, the bottom of the outer flow guide cover 6 is provided with a liquid suction port, a screen 7 is arranged at the liquid suction port, and a liquid phase enters an annular gap between the inner downcomer and the outer flow guide cover from the liquid suction port and then enters the inner downcomer 5.

The plurality of suspended downcomers (5, 6) are respectively and uniformly distributed on the tray 1, and the suspended downcomers (5, 6) and the gas-liquid contact elements (2, 3) are mutually and alternately distributed on the tray.

The diameter of a suspended liquid receiving plate 9 below the inner downcomer 5 is 100mm, the overflow weir of the liquid receiving plate is a tooth-shaped overflow weir, and the tooth depth is 15 mm.

Two side line openings (catalyst loading and unloading openings) 8 are arranged on the tower tray at the height between the liquid level below the tower wall corresponding to each layer of tower tray and the tower tray and are symmetrically distributed on the tower tray, and a flow deflector 10 is arranged on the tower tray close to the catalyst loading and unloading opening 8.

The arrangement and the holes of the spraying cap are shown in figures 3-5, the air holes are trapezoidal holes with wide bottoms and narrow tops, and the flow deflector is shown in a picture of figure 5. The lower part of the injection cap 3 is provided with a screen mesh to prevent the catalyst from entering the downcomer. The riser is 100mm higher than the special tray of the tray, so that the liquid can not leak from the downcomer in a normal operation state; the gas-raising tube is cylindrical, and the top cross section of the cap is circular.

The inner downcomer 5 is circular, the downcomers of the upper and lower layers of tower trays are not overlapped, and the inner downcomer rotates by an angle of 45 degrees in the horizontal direction.

The catalyst on-line replacement process comprises the following steps: referring to fig. 6, while the catalytic distillation column is still in operation, the left side opening 8 is gradually opened to allow the liquid on the tray to gradually enter the catalyst replacement outer tube 15, after the tube is filled, the pump 14 is started, the right side opening 8 is opened, and the liquid flows in the tube in the annular space formed by the tray and the catalyst replacement outer tube 15 in the direction indicated by the arrow of the pump in the figure. The catalyst on the tray gradually enters the catalyst exchange tube 11 with the liquid, and is intercepted in the catalyst exchange tube 11 by the mesh 12 at one end of the catalyst exchange tube 11. Until the catalyst on the tray is completely replaced in the catalyst replacement tubes 11, the side openings 8 are closed. The removal flange 13 is opened to remove the catalyst replacement pipe 11 as a whole, and a replacement pipe containing a new catalyst is installed at the position of the original catalyst replacement pipe 11. Changing the direction of the pump 14 to pump liquid from right to left, opening an annular gap formed by the right side line open pore 8 and the catalyst replacement outer tube 15, gradually flowing the liquid on the tray into the pump 14, starting the pump 14 to pump liquid from right to left, flushing new catalyst onto the tray through the left side line open pore 8, initially dispersing the catalyst on the tray through a deflector 10 before the side line open pore 8, intercepting the catalyst on the tray by a right screen 12, running until the catalyst in the catalyst replacement tube 11 is completely replaced on the tray, and closing the two side line open pores 8. Then under the impact of the upper descending liquid and the flow disturbance of the liquid on the tray, the uniform distribution of the catalyst on the tray is gradually realized. Then the catalyst is replaced layer by layer, only one tray is replaced each time, and the influence can be controlled within an acceptable range for the catalytic rectifying tower comprising a plurality of stages of trays.

Comparative application

A catalytic rectification column with diameter DN800 shown in figure 7 comprises, from top to bottom, a rectification section 16, a reaction section 17, and a stripping section 18, wherein the reaction section 17 is filled with 8m Sulshou catalytic rectification component (model KATAPAKTM-SP), and the catalyst (sulfonic acid type ion exchange resin) is filled with 1.2m³. The reaction pressure is 2BarA, the temperature of a reaction section is 80-105 ℃, the feeding of a raw material TBA is 1000kg/h, the conversion rate of the TBA is 99%, and the selectivity of IB is 99%.

Application examples

The rectification section and the stripping section of the device are the same as the comparative example, the reaction section is replaced by 30 novel trays, tray elements and holes of a spraying cap in the embodiment 1, the guide design is designed according to the scheme of figures 1-3, wherein only half area of the spraying cap is provided with holes (as shown in figure 3, the left half side is provided with a guide vane, the right half side is not provided with holes at all; a liquid phase on the tower tray is pushed to be in a counterclockwise flowing state), the height of a weir is 200mm, the catalyst loading is 2m³. The reaction pressure is 2BarA, the raw material TBA is fed in 2000kg/h, the conversion rate of TBA is 99 percent, and the IB selectivity is 99 percent. From the results, on the premise of ensuring that the catalytic effect is basically the same as that of packing fillers, the catalytic distillation tower disclosed by the invention has the advantages that the processing capacity is remarkably improved, the equipment investment and the catalyst cost are remarkably reduced.

Claims

1. A catalytic rectification tower plate capable of replacing a catalyst on line is characterized by comprising a tower tray, a plurality of gas-liquid contact elements and a plurality of suspended downcomers which are arranged on the tower tray, a suspended liquid receiving disc positioned below the suspended downcomers and a catalyst loading and unloading hole which is arranged on the tower wall and used for loading and unloading the catalyst on the tower tray, wherein a free space enclosed by the suspended downcomers, the gas-liquid contact elements, the tower tray and the tower wall is a catalyst loading area, the catalyst is scattered and stacked in the catalyst loading area, the suspended downcomers comprise inner downcomers penetrating through the tower tray and outer flow guide covers covering the upper part of the bottom of the tower tray of the inner downcomers,

the bottom of the outer diversion cover is provided with a liquid suction port, a screen is arranged at the liquid suction port, and a liquid phase enters an annular gap between the inner downcomer and the outer diversion cover from the liquid suction port and further enters the inner downcomer;

the number of side line openings of each layer of tower tray is 2N, wherein N is 1-10, and flow deflectors which are used for facilitating the liquid phase to drive the catalyst to be uniformly distributed when the catalyst is replaced are arranged on the tower tray and at the position 50-500 mm from the side line openings to the inner side of the tower tray;

a screen is arranged between one of the side line openings of each layer of tray and an external catalyst replacing system, wherein the catalyst replacing system comprises a catalyst replacing outer pipe connected with the two side line openings, the catalyst replacing outer pipe comprises a section of detachable catalyst replacing pipe, one end of the catalyst replacing pipe is provided with a screen for intercepting the catalyst in the catalyst replacing pipe, and the catalyst replacing outer pipe is provided with a pump capable of pumping liquid in two directions.

2. A catalytic rectification tray as claimed in claim 1, characterized in that the gas-liquid contact element comprises a riser mounted on the tray and a spray cap mounted on the upper part of the riser, the spray cap being provided with gas spray holes at a position below the liquid level at the lower end and/or lower part.

3. A catalytic rectification tray as claimed in claim 2 wherein flow deflectors are provided adjacent the gas injection holes.

4. A catalytic rectification tray as claimed in any one of claims 1 to 3 wherein the plurality of overhead downcomers are each evenly distributed on the tray, the overhead downcomers and the gas-liquid contact elements being staggered with respect to one another on the tray.

5. A catalytic rectification tray as claimed in any one of claims 1 to 3 wherein catalyst loading and unloading holes for loading and unloading catalyst on the trays are provided at a level between the tray and below the liquid level on the corresponding column wall of each tray.

6. A catalytic rectification column plate according to claim 2 or 3, characterized in that the vertical distance from the lower end of the injection cap to the tray is 5-95% of the height of the liquid layer on the tray, and the gas-liquid contact element has a gas-lift pipe 20-1000 mm higher than the bottommost end of the tray.

7. A catalytic rectification tray as claimed in claim 2 or 3 wherein the vertical distance of the lower end of the spray cap from the tray is between 10% and 50% of the height of the liquid layer on the tray.

8. A catalytic rectification tray as claimed in claim 2 or 3 wherein the risers are cylindrical, elliptical or trapezoidal or tapered with a narrowing cross-section upwards;

the cross section of the injection cap is circular or elliptical or the cross section of the injection cap is trapezoidal or conical which is gradually narrowed upwards;

the inner downcomers and the outer guide covers are circular, square or strip-shaped, and the number of the suspended downcomers of each layer of tower tray is 2-200.

9. A catalytic rectification tray as claimed in claim 8 wherein the number of overhead downcomers per tray is from 5 to 20.

10. A catalytic rectification tray as claimed in any one of claims 1 to 3 wherein the inner downcomers of the upper and lower trays do not vertically overlap.

11. The catalytic rectification tray of claim 10, wherein the downcomers of two adjacent trays rotate horizontally by an angle of 0-90 °.

12. A catalytic rectification tray as claimed in claim 2 or 3 wherein the openings in the spray caps are non-uniform; when the cross section of the injection cap is circular or similar to a circle, a plurality of holes are formed on one side of a connecting line of the midpoint of the tray and the geometric center of the injection cap, and no holes or few holes are formed on the other side; and/or

The direction of the flow deflector beside the gas jet hole of the jet cap cover forms an angle of 0-90 degrees with the connecting line of the midpoint of the tower tray and the geometric center of the jet cap cover, and forms an angle of 0-45 degrees with the horizontal flow direction of the liquid.

13. A catalytic rectification column plate according to any one of claims 1 to 3, characterized in that a suspended liquid receiving plate is arranged at the lower end of the suspended downcomer, the shape of the suspended liquid receiving plate corresponds to that of the downcomer, the lower end of the downcomer is 50-200 mm away from the liquid receiving plate, and the width of the liquid receiving plate is 10-200 mm larger than that of the downcomer.

14. A catalytic rectification tray as claimed in claim 13 wherein the suspended liquid receiving tray employs a toothed weir.

15. Use of a catalytic rectification tray according to any one of claims 1 to 14 for a process for the catalytic rectification of tert-butanol for the preparation of isobutene.