CN219559201U - Absorption tower tar cleaning device in maleic anhydride production - Google Patents

Abstract

The utility model discloses a tar cleaning device of an absorption tower in maleic anhydride production, which comprises an absorption tower, tar settling equipment, a maleic anhydride recovery tank and a decoking separation tank, wherein the tar settling equipment comprises 2 settling tanks; heavy component impurities in the rich solvent of the absorption tower are settled in a settlement device and then enter a maleic anhydride recovery tank, the solvent which comprises tar and removes maleic anhydride is obtained after flash evaporation separation and enters a decoking separation tank for layering, and materials which comprise tar and alkaline water for flushing are obtained from the bottom of the tank. According to the utility model, heavy component impurities in the rich solvent of the absorption tower are removed by arranging the maleic anhydride recovery tank and the tar settling tank, so that tar at the bottom of the absorption tower can be cleaned under the condition of no production stopping, the operation is simple and convenient, and the problems of environmental pollution and difficult operation of overhaul sites caused by regular shutdown overhaul are avoided; the multistage maleic anhydride and solvent recovery procedure is set, so that maleic anhydride and solvent are recovered to the greatest extent, and the process cost is reduced.

Description

Absorption tower tar cleaning device in maleic anhydride production

Technical Field

The utility model relates to the technical field of maleic anhydride production, in particular to a tar cleaning device of an absorption tower in maleic anhydride production.

Background

Maleic anhydride, maleic anhydride for short, is also called maleic anhydride, is an important organic chemical raw material product, is called as a tri-large anhydride raw material together with acetic anhydride and phthalic anhydride, is widely used in traditional fields of synthetic resin, paint, medicine, pesticide, lubricating oil, paper making, food and the like, and has become an important raw material for the downstream electric and electronic industries such as electronic packaging, electric insulation, degradable plastics, photoresist and the like, new materials and the like in recent years.

Raw material benzene or n-butane and air are subjected to oxidation reaction in maleic anhydride production to obtain reaction generated gas containing maleic anhydride, and then the maleic anhydride product is obtained through the technological processes of cooling, absorption, desorption, refining recovery and the like. Because the reaction generated gas is a mixture composed of a plurality of gases, the reaction generated gas not only comprises reaction raw materials and products such as maleic anhydride, air and the like, but also comprises impurities such as water, acetic acid, acrylic acid and the like and heavy component impurities which can be condensed into tar, in the absorption process, the generated tar can be accumulated at the bottom of an absorption tower, so that the bottom of the absorption tower is coked and blocked, and the normal production is influenced.

Aiming at the problems, the current common practice in the industry is as follows: 1) Reducing tar accumulation at the bottom of the absorption tower by periodically cleaning tar of a heat exchanger at a front working section, and disassembling and integrally cleaning related pipelines; 2) And (3) stopping and maintaining at regular intervals (for example, about 20 days), uncovering and overhauling the absorption tower, cleaning tar at the bottom of the tower, and disassembling and integrally cleaning related pipelines and equipment. The above method may affect continuous production or at least set up 2 sets of equipment to ensure continuous production and thus increase equipment investment; in addition, the operation of the cover opening overhaul mode is easy to cause serious environmental pollution, and has the defects of difficult operation at maintenance sites and the like.

Patent CN103193739a proposes to deliver heavy impurities (mainly tar) together with a rich solvent to a conical tower bottom part of a stripping tower, standing and layering, extracting the rich solvent at the middle lower part of the tower bottom, and extracting heavy component impurities from the tower bottom when the heavy impurities in the tower bottom reach a certain amount. The method has long standing time, and the tar temperature is not easy to control so that the tar is kept in a liquid state, and once the tar is coagulated, a pipeline is easy to be blocked, so that the subsequent treatment of maleic anhydride heavy component impurities can be influenced.

Disclosure of Invention

Aiming at the defects of the prior art, the utility model discloses a tar cleaning device for an absorption tower in maleic anhydride production, which can timely discharge tar in the absorption tower while ensuring continuous production of maleic anhydride, is simple and convenient to operate, and is convenient to overhaul, so that tar cleaning work in maleic anhydride production is more environment-friendly and safer.

Specifically, the utility model relates to a tar cleaning device of an absorption tower in maleic anhydride production, which comprises:

and the absorption tower is used for fully contacting the solvent with reaction generated gas containing maleic anhydride obtained by oxidizing raw material benzene or n-butane with air, and absorbing maleic anhydride gas in the reaction gas to obtain a rich solvent rich in maleic anhydride. Solvents which are generally used for the absorption of maleic anhydride are aromatic esters, such as dibutyl phthalate (DBP) or hexahydrophthalic acid and dicarboxylic acid (DIBE).

The tar settling device comprises a first settling tank and a second settling tank; the tower kettle discharge port of the absorption tower is respectively communicated with the top feed inlets of the first settling tank and the second settling tank through pipelines, and the feed pipe is provided with a protruding part in the tank bodies of the first settling tank and the second settling tank; and top discharge ports of the first settling tank and the second settling tank are respectively communicated with a subsequent desorption process through pipelines.

And the maleic anhydride recovery tank is provided with a feed inlet, a top discharge port and a bottom discharge port, and the feed inlet is respectively communicated with the bottom discharge ports of the first settling tank and the second settling tank through pipelines. The top discharge port of the maleic anhydride recovery tank is used for outputting the flashed rich solvent rich in maleic anhydride and all n-butane, water, acrylic acid and the like, and the partial material can enter a rich solvent further concentration process, return to an absorption tower or enter a subsequent desorption process.

The feeding port of the decoking separation tank is communicated with the bottom discharging port of the maleic anhydride recovery tank through a pipeline; the decoking separation tank is also provided with a bottom discharge hole and a first discharge hole at the same height position of the feed inlet. The feed inlet and the first discharge port of the decoking separator are all arranged below the water seal liquid level, materials which are extracted from the bottom of the maleic anhydride recovery pipe and comprise tar and solvent for removing maleic anhydride are subjected to standing layering in the decoking separation tank, the water seal liquid level and the oil layer are extracted from the first discharge port, the materials enter the subsequent solvent treatment process, or the solvent phase and the acid-containing water phase are separated through the gravity centrifugation process, the obtained solvent phase can be recycled, and the obtained acid-containing water phase enters the subsequent sewage treatment process. And extracting tar and alkaline water for flushing from a bottom discharge hole of the decoking separation tank, wherein the part of materials are concentrated and enter subsequent treatment.

Optionally, the discharging pipes communicated with the top discharging holes of the first settling tank and the second settling tank are provided with protruding parts in the first settling tank and the second settling tank; a longitudinal baffle plate is arranged between the feed pipe protruding parts and the discharge pipe protruding parts of the first settling tank and the second settling tank. It will be appreciated by those skilled in the art that it is also possible to use a longitudinal partition only in the first or second settling tank, and that the resulting solution is within the scope of the utility model.

Optionally, the protruding parts of the feeding pipes of the first settling tank and the second settling tank are deep into the tank body to a certain depth, so that when materials extracted from the discharge hole of the tower kettle of the absorption tower are fed into the first settling tank and the second settling tank, downward impact force is generated under the action of gravity and kinetic energy of the materials, and tar in the materials is promoted to separate and settle; for example, the outlet ends of the feed pipe projections of the first settling tank and the second settling tank may be provided at positions corresponding to 1/4 to 3/4 of the height of the tank body, or further may be provided at positions corresponding to 1/2 to 3/4 of the height of the tank body.

Optionally, the tops of the first settling tank and the second settling tank are respectively provided with a first cleaning medium inlet and a second cleaning medium inlet which are communicated with the cleaning medium input pipeline.

Further optionally, the first cleaning medium inlet and the second cleaning medium inlet are respectively communicated with a low pressure steam (LS) input pipe and a nitrogen (N) input pipe through pipelines.

In actual industrial production, the first settling tank and the second settling tank can be alternately used for settling and tar cleaning. Specifically, in one staged operating mode: and a feed inlet of the first settling tank is communicated with a tower kettle discharge outlet of the absorption tower through a pipeline, and a rich solvent rich in maleic anhydride obtained after solvent absorption is input for tar deposition. At this time, the tar deposition of the second settling tank is completed, and the deposited solvent and tar are input into the maleic anhydride recovery tank from a discharge hole at the bottom of the second settling tank, so as to carry out a tar cleaning procedure; after the output of the second settling tank is finished, low-pressure steam is input from a second cleaning medium inlet, residual tar in the tank is flushed and discharged through pressurization, then nitrogen is input into a nitrogen blow-drying tank, nitrogen sealing is carried out, and the low-pressure steam is continuously and circularly used as a standby settling tank of the first settling tank for tar cleaning. It should be noted that, based on the present utility model, a person of ordinary skill in the art can set up more than 2 settling tanks through non-creative labor, and continuously and circularly clean tar in the absorption tower in maleic anhydride production, so that the formed technical scheme is within the protection scope of the present utility model.

Optionally, a third cleaning medium inlet communicated with the cleaning medium input pipeline is arranged at the top of the maleic anhydride recovery tank.

Further optionally, the third cleaning medium inlet is connected to an alkaline water (CAW) input pipe via a pipeline.

Still further optionally, the third cleaning medium inlet is in communication with a low pressure steam (LS) input line and a water (PW) line via a pipeline.

Optionally, the top discharge gate of maleic anhydride recovery tank is through pipeline intercommunication evacuating device, therefore this discharge gate is the vacuum extraction opening, but negative pressure is taken out maleic anhydride and normal butane, water, acrylic acid etc. that flash off through maleic anhydride recovery tank, can guarantee simultaneously that the flash distillation process in the maleic anhydride recovery tank carries out under the vacuum, further promotes the separation of light, heavy components, promotes the technological effect of flash distillation.

Optionally, the maleic anhydride recovery tank is a flash tank.

Further optionally, the maleic anhydride recovery tank is a horizontal flash tank.

Still further optionally, the maleic anhydride recovery tank is a flash tank provided with electrical heating or steam tracing.

Optionally, the maleic anhydride recovery tank is provided with a glass plate liquid level meter, so that the liquid level and layering condition in the tank body can be observed conveniently.

Optionally, a fourth cleaning medium inlet communicated with the cleaning medium input pipeline is arranged at the top of the decoking separation tank.

Further optionally, the fourth cleaning medium inlet is connected to an alkaline water (CAW) input pipe via a pipeline.

Still further optionally, the fourth cleaning medium inlet is in communication with a low pressure steam (LS) input line and a water (PW) line via a pipeline.

Optionally, the decoking separation tank is provided with a glass plate liquid level meter, so that the liquid level and layering condition in the tank body can be observed conveniently.

It should be noted that, for convenience in control, valves are correspondingly arranged on the pipelines of the tar cleaning device of the absorption tower in maleic anhydride production; the valve type can be ball valve, butterfly valve, etc., and the important control site can be electromagnetic valve. Those skilled in the art can select a proper valve type, a proper valve mounting position and a proper valve mounting mode through non-creative labor, and the formed technical scheme is within the protection scope of the utility model.

Compared with the prior art, the utility model has the beneficial effects that:

1. the maleic anhydride recovery tank and the tar settling tank are arranged to remove heavy component impurities in the rich solvent of the absorption tower, so that tar in the rich solvent of the tower bottom of the absorption tower can be cleaned under the working condition of no production stopping, the operation is simple and convenient, and the problems of environmental pollution and difficult operation of overhaul sites caused by regular shutdown overhaul can be avoided;

2. the settling tank, the maleic anhydride recovery pipe and the tar settling tank are cleaned by communicating the cleaning medium pipeline, so that other equipment and pipelines are not required to be cleaned additionally, and the problem of high investment cost of a device for cleaning tar in the current industry can be effectively solved; the tar cleaning process is carried out in a closed and water-sealed state, so that the surrounding environment is not influenced by exposing the tar to the air, and the environment is more environment-friendly and safer.

3. The maleic anhydride and solvent recovery procedure is set, so that the maleic anhydride and the solvent are recovered to the greatest extent, and the cost of industrial production of the maleic anhydride is obviously reduced.

Drawings

The accompanying drawings, which are included to provide a further understanding of the utility model and are incorporated in and constitute a part of this specification, illustrate embodiments of the utility model and together with the description serve to explain the utility model.

In the drawings:

FIG. 1 is a schematic diagram of a tar cleaning device of an absorption tower in maleic anhydride production;

wherein the above figures include the following reference numerals:

1-absorber, 11-first flow, 21-first settling tank, 22-second settling tank, 23-second flow, 24-third flow, 3-maleic anhydride recovery tank, 31-fourth flow, 32-fifth flow, 33-glass plate level gauge, 4-decoking separation tank, 41-sixth flow, 42-seventh flow.

Detailed Description

The technical solutions of the embodiments of the present utility model will be clearly and completely described below with reference to the drawings in the present embodiment, and it is apparent that the described embodiments are only some embodiments of the present utility model, not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the utility model without making any inventive effort, are intended to be within the scope of the utility model.

The utility model will be described in further detail below with reference to the drawings by means of specific embodiments. It should be noted that relational terms such as "first" and "second" and the like in the present embodiment are used solely to distinguish one element from another element having the same name, and do not necessarily require or imply any such actual relationship or order between the elements. Features defining "first," "second," etc. may explicitly or implicitly include one or more such features.

In the description of the present utility model, it should be noted that, unless explicitly specified and defined otherwise, the term "connected" shall be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium, and can be communication between two elements. The specific meaning of the above terms in the present utility model can be understood by those of ordinary skill in the art in a specific case. It should be noted that, without conflict, the embodiments of the present utility model and features of the embodiments may be combined with each other.

Example 1

An absorber tar cleaning device in maleic anhydride production, as shown in fig. 1, the device comprises:

an absorption tower 1;

a tar settling device comprising a first settling tank 21 and a second settling tank 22; the tower kettle discharge port of the absorption tower 1 is respectively communicated with the top feed ports of the first settling tank 21 and the second settling tank 22 through pipelines, and the feed pipes are provided with protruding parts (for the sake of brevity, not labeled in the figure) in the tank bodies of the first settling tank 21 and the second settling tank 22; the top discharge ports of the first settling tank 21 and the second settling tank 22 are respectively communicated with the subsequent desorption process through pipelines;

the maleic anhydride recovery tank 3 is provided with a feed inlet, a top discharge port and a bottom discharge port, and the feed inlet is respectively communicated with the bottom discharge ports of the first settling tank 21 and the second settling tank 22 through pipelines;

a decoking separation tank 4, the feed inlet of which is communicated with the bottom discharge port of the maleic anhydride recovery tank 3 through a pipeline; the decoking separation tank 4 is also provided with a bottom discharge hole and a first discharge hole at the same height position as the feed hole.

Optionally, the discharge pipes communicating with the top discharge ports of the first settling tank 21 and the second settling tank 22 are provided with protruding parts (not labeled in the figure for the sake of brevity) in the first settling tank 21 and the second settling tank 22; a longitudinal partition (not shown for the sake of brevity) is provided between the feed pipe projections and the discharge pipe projections of the first and second settling tanks 21, 22.

Optionally, the top of the first settling tank 21 and the second settling tank 22 are provided with a first cleaning medium inlet (not labeled in the figure for the sake of brevity) and a second cleaning medium inlet (not labeled in the figure for the sake of brevity) which are communicated with the cleaning medium input pipeline; and the two cleaning medium inlets are respectively communicated with the low-pressure steam input pipe and the nitrogen input pipe through pipelines.

Optionally, a third cleaning medium inlet (not labeled for the sake of brevity) is provided at the top of the maleic anhydride recovery tank 3, which communicates with the cleaning medium input line; the third cleaning medium inlet is communicated with the low-pressure steam input pipe, the alkaline water input pipe and the water delivery pipe through pipelines.

Optionally, a fourth cleaning medium inlet (not labeled for the sake of brevity) is provided at the top of the decoking separator tank 4, which communicates with the cleaning medium inlet line; the fourth cleaning medium inlet is communicated with the low-pressure steam input pipe, the alkaline water input pipe and the water delivery pipe through pipelines.

Optionally, the top discharge port of the maleic anhydride recovery tank 3 is communicated with a vacuum pumping device through a pipe.

Example 2

The present embodiment shows a process flow of cleaning tar in maleic anhydride production by using the absorption tower tar cleaning device in maleic anhydride production shown in embodiment 1 under a specific working condition, and the process flow is only a preferred flow, and does not limit the protection scope of the present utility model.

Benzene or n-butane and air are subjected to oxidation reaction to obtain reaction generated gas containing maleic anhydride, the reaction generated gas is input into the absorption tower 1, and after maleic anhydride gas is absorbed by the solvent DBP, a first flow 11 rich in maleic anhydride is produced in the tower bottom of the absorption tower 1. The first stream 11 is fed to a first 21 and a second 22 settling tank, respectively, in a tar settling device.

Because the pipe bodies of the feeding pipes communicated with the top feeding holes of the two settling tanks extend into the tank bodies, the gravity and kinetic energy of the first flow 11 generate downward impact force when feeding, and tar separation and settlement are promoted; the arrangement of the longitudinal partition plates can promote the deposition of more tar and reduce the times of tar cleaning.

Alternatively, the two tar settling tanks are approximately Φ600×800 in size.

The discharge pipe body connected to the top discharge openings of the first 21 and second 22 settling tanks extends to the other side of the longitudinal partition and discharges a second stream 23 with a tar content of about 7% and rich maleic anhydride. The tar accumulates in the settling tank and when a certain amount is reached, a third stream 24 is periodically discharged from the bottom discharge port of the second settling tank 22 to the maleic anhydride recovery tank 3, and the third stream 24 mainly comprises the solvent and tar after deposition.

In the maleic anhydride recovery tank 3, the third stream 24 is flashed at about 110 ℃ to obtain a fourth stream 31, the fourth stream 31 comprising about 90% of the maleic anhydride dissolved in the third stream 24 and all of the n-butane, water, acrylic acid, etc., and the fourth stream 31 is withdrawn from the top outlet of the maleic anhydride recovery tank 3 and fed to a further concentration step of the rich solvent, to an absorption column or to a subsequent desorption step. During the process, the liquid level and layering can be observed by a glass plate level gauge 33 on the maleic anhydride recovery tank 3. It is noted that the top discharge port of the maleic anhydride recovery tank 3 is connected to the vacuum device via a pipeline, so that the discharge port is a vacuum suction port, and the fourth stream 31 can be drawn out under negative pressure, and the flash evaporation process in the maleic anhydride recovery tank 3 can be ensured to be performed under vacuum. A fifth stream 32 is withdrawn from the bottom outlet of maleic anhydride recovery tank 3 and fed to decoking separator tank 4, the fifth stream 32 comprising mainly tar and solvent for removing maleic anhydride.

A water seal liquid level is arranged in the decoking separation tank 4, and a feed inlet and a first discharge outlet of the decoking separation tank 4 are both arranged below the water seal liquid level. The fifth stream 32 is kept stand in the decoking separation tank 4 for about 2 hours, and after layering, a sixth stream 41 is extracted from the first discharge port, wherein the sixth stream 41 comprises a water seal liquid level and an oil layer (namely, comprises a solvent DBP and water) in the decoking separation tank 4; the sixth stream 41 may be passed through a circulation pump to a subsequent solvent treatment process; or the solvent phase and the water phase are obtained through the gravity centrifugation process, the solvent can be recycled, and the obtained acid-containing water phase can enter the subsequent sewage treatment process.

The process flow shown in this example can recover more than about 99% of the solvent DBP.

A seventh stream 42 is withdrawn from the bottom outlet of decoking knockout drum 4, and this seventh stream 42 is primarily tar and aqueous caustic for flushing. This seventh stream 42 is concentrated for subsequent processing.

Example 3

The utility model also provides the technical characteristics for promoting tar cleaning, and the specific process flow is as follows on the basis of the embodiment 2:

the tops of the first settling tank 21 and the second settling tank 22 are respectively provided with a first cleaning medium inlet and a second cleaning medium inlet, low-pressure steam is input through the first cleaning medium inlet and the second cleaning medium inlet after the third stream 24 is discharged, residual tar in the tanks is flushed and discharged through pressurization, and then nitrogen is input into the nitrogen gas to blow the tanks to dry the tanks for nitrogen sealing. By adopting the cleaning mode, the sedimentation tank does not need to be opened for cleaning, and tar exposure is prevented.

From the outside, in order to avoid the incomplete operating mode of tar clearance, set up the alkaline water interface respectively in maleic anhydride recovery tank 3 and decoking knockout drum 4, when the jar is interior because of the more and condensing of tar, can follow the fourth cleaning medium entry at jar body top and import alkaline water and clear away the tar to can select input water and/or low pressure steam to assist, make the tar clear away more high-efficient. In addition, the fourth cleaning medium inlet of the decoking separation tank 4 is connected with a water pipe through a pipeline, and can also be used for supplementing water before water seal decoking.

The foregoing is a further detailed description of the utility model in connection with specific embodiments, and it is not intended that the utility model be limited to such description. It will be apparent to those skilled in the art that several simple modifications and adaptations of the utility model can be made without departing from the spirit of the utility model and are intended to be within the scope of the utility model.

Claims (10)

1. The utility model provides a device for cleaning tar in absorption tower in maleic anhydride production which characterized in that, this device includes

An absorption tower (1);

a tar settling device comprising a first settling tank (21) and a second settling tank (22); the tower kettle discharge port of the absorption tower (1) is respectively communicated with the top feed inlets of the first settling tank (21) and the second settling tank (22) through pipelines, and the feed pipes are provided with protruding parts in the tank bodies of the first settling tank (21) and the second settling tank (22); the top discharge ports of the first settling tank (21) and the second settling tank (22) are respectively communicated with the subsequent desorption process through pipelines;

the maleic anhydride recovery tank (3) is provided with a feed inlet, a top discharge outlet and a bottom discharge outlet, and the feed inlet of the maleic anhydride recovery tank (3) is respectively communicated with the bottom discharge outlets of the first settling tank (21) and the second settling tank (22) through pipelines;

a decoking separation tank (4), wherein a feed inlet of the decoking separation tank is communicated with a bottom discharge outlet of the maleic anhydride recovery tank (3) through a pipe; the decoking separation tank (4) is also provided with a bottom discharge hole and a first discharge hole at the same height position of the feed inlet.

2. The device for cleaning tar in an absorption tower in maleic anhydride production according to claim 1, wherein the discharge pipes communicated with the top discharge ports of the first settling tank (21) and the second settling tank (22) are provided with protruding parts in the tank bodies of the first settling tank (21) and the second settling tank (22); a longitudinal baffle is arranged between the feed pipe protruding part and the discharge pipe protruding part of the first settling tank (21) and/or the second settling tank (22).

3. The tar cleaning apparatus for an absorption tower in maleic anhydride production according to claim 1, wherein the top parts of the first settling tank (21) and the second settling tank (22) are respectively provided with a first cleaning medium inlet and a second cleaning medium inlet which are communicated with a cleaning medium input pipeline.

4. The apparatus for cleaning tar in an absorption tower in maleic anhydride production according to claim 3, wherein the first cleaning medium inlet and the second cleaning medium inlet are connected to a low pressure steam inlet pipe and a nitrogen inlet pipe, respectively, via pipes.

5. The device for cleaning tar in an absorption tower in maleic anhydride production according to claim 1, wherein a third cleaning medium inlet communicated with a cleaning medium input pipeline is arranged at the top of the maleic anhydride recovery tank (3).

6. The apparatus for cleaning tar in an absorption tower in maleic anhydride production according to claim 5, wherein the third cleaning medium inlet is connected to an alkaline water input pipe via a pipeline.

7. The device for cleaning tar in an absorption tower in maleic anhydride production according to claim 6, wherein the third cleaning medium inlet is further connected with a low-pressure steam input pipe and/or a water delivery pipe through a pipeline.

8. The tar cleaning device for the absorption tower in maleic anhydride production according to claim 1, wherein a fourth cleaning medium inlet communicated with a cleaning medium input pipeline is arranged at the top of the decoking separation tank (4).

9. The device for cleaning tar in an absorption tower in maleic anhydride production according to claim 8, wherein the fourth cleaning medium inlet is connected to an alkaline water input pipe via a pipeline.

10. The device for cleaning tar in an absorption tower in maleic anhydride production according to claim 9, wherein the fourth cleaning medium inlet is further connected to a low pressure steam inlet pipe and/or a water pipe via a pipeline.