CN218573315U - Mixing device for preparing ethylbenzene by liquid-phase benzene alkylation - Google Patents

Abstract

The utility model discloses a mixing arrangement of liquid phase benzene alkylation system ethylbenzene belongs to the chemical industry field. The device is sequentially provided with a first gas distributor, a premixing internal part, a steady flow section, a second gas distributor and a mixing internal part from bottom to top, the bottom of the device is provided with a raw material feeding hole, and the top of the device is provided with a discharging hole. The utility model provides a system vibration of ethylene-benzene mixing process mixed absorption device eliminates the safety risk.

Description

Mixing device for preparing ethylbenzene by liquid-phase benzene alkylation

Technical Field

The utility model relates to a chemical industry field, concretely relates to mixing arrangement of liquid phase benzene alkylation system ethylbenzene.

Background

Ethylbenzene is a raw material for producing styrene monomers, and styrene is one of important organic chemical raw materials, so that various engineering plastics, synthetic resins, synthetic rubbers and other high polymer materials are synthesized. There are many methods for producing ethylbenzene, and with the continuous progress of the process technology, the technology for producing ethylbenzene by a molecular sieve liquid phase alkylation method gradually shows advantages.

The liquid phase method makes the raw material benzene in liquid phase by means of higher pressure, in the pure ethylene process, ethylene exists in a reactor in a liquid phase form, belongs to a liquid-solid two-phase reaction type, and has a very mature technology at home and abroad; for the dilute ethylene process, the inert gas in the dilute ethylene still exists in a gas form, and belongs to a gas-liquid-solid three-phase reaction, which is the main difference between the dilute ethylene process and a pure ethylene process.

The liquid phase process utilizes relatively high pressure to maintain the feedstock benzene in the liquid phase and the ethylene is usually in the gaseous state prior to entering the alkylation reactor, a common technique being that after the ethylene is thoroughly mixed with the benzene at high pressure, the ethylene dissolves into the benzene and enters the reactor catalyst bed in the liquid phase. Ethylene is completely dissolved in benzene and fully mixed, which is a key link of a pure ethylene process, in the process, gaseous ethylene is completely converted into liquid and is absorbed and dissolved by liquid benzene, ethylene is converted into liquid from gaseous state in the process, the volume of the mixture is rapidly reduced, the disturbance of an ethylene-benzene mixing system is caused, the mixing device vibrates, and even the system leakage is possibly caused by long-term vibration, so that safety accidents occur.

SUMMERY OF THE UTILITY MODEL

The utility model aims at the above-mentioned problem provide an ethylene benzene mixing arrangement of liquid phase benzene alkylation system ethylbenzene, dissolve gaseous state ethylene to benzene under the high pressure, realize intensive mixing, solve the vibration problem of system.

The purpose of the utility model can be realized by the following technical scheme:

a mixing device for preparing ethylbenzene by liquid phase benzene alkylation is provided with a first gas distributor, a premixing internal part, a steady flow section, a second gas distributor and a mixing internal part from bottom to top in sequence, wherein the bottom of the device is provided with a raw material inlet, and the top of the device is provided with a material outlet.

The utility model discloses among the technical scheme: the ethylene input lines are connected to the first gas distributor and the second gas distributor, respectively.

The utility model discloses among the technical scheme: the premixing internals and the mixing internals are corrugated plates.

The utility model discloses among the technical scheme: the mixing device is of a vertical structure.

The specific working process and principle are as follows:

the mixing device for dissolving ethylene in benzene has a vertical structure and is divided into a premixing absorption area and a mixing absorption area, and a steady flow section is arranged between the premixing absorption area and the mixing absorption area.

The premixing absorption zone and the mixing absorption zone are both arranged in a circular cylindrical container, and the mixing internal parts in the container adopt corrugated plates to realize static absorption and full mixing of ethylene and benzene.

The working principle is that the fluid passes through the corrugated plates in the circular cylindrical container, the corrugated plates divide the mixture of benzene and ethylene into a plurality of strands, the fluid between the corrugated plates is controlled to be in a laminar state, severe vortex is prevented from being generated in the section direction, the absorption-mixing process of fluid division-position movement-re-convergence is realized, and the mixing section is not provided with a moving part and only provided with a static element corrugated plate and a support piece thereof.

Due to the action of the corrugated plate component, the fluid rotates leftwards and rightwards, the flowing mixing direction is changed continuously, the central fluid is pushed to the periphery, and the peripheral fluid is pushed to the center, so that a good radial mixing effect is achieved. Meanwhile, the rotation action of the fluid per se also occurs on the joint of the adjacent components, and the perfect radial circulation mixing action can achieve the aim of uniformly mixing the materials.

The static mixing ratio of the corrugated plate to the perforated plate is much superior to that of a Venturi and stirring paddle mixer. The said device is installed in the pipe by regular packing made up of corrugated plates, and has the advantages of small volume, large flow, small pressure drop, low energy consumption, uniform mixing, convenient production, simple operation and low investment.

The static mixing device is a cylinder assembled by corrugated plates with certain specifications, and has the technical characteristics that the highest dispersion degree is 1-2 mu m, and the liquid phase and gas phase unevenness coefficient is less than or equal to 1-5%. It is suitable for liquid-gas absorption of benzene and ethylene. It can make the benzene and ethylene fluid implement Z-shaped flow in three-dimensional space

The perfect radial circulation mixing effect can obviously reduce the temperature gradient, the velocity gradient and the mass gradient of the fluid on the section of the pipe. Ethylene and benzene are fully dispersed in the mixer, which is beneficial to fully dissolving ethylene into benzene, in addition, because the benzene flow in the benzene and ethylene mixing device is usually very large, the structure can meet the requirement of large flow, and because the pressure drop is small, the possibility of resolving ethylene caused by the reduction of the fluid pressure after absorption is small. The vertical structure is beneficial to the uniform distribution of gaseous ethylene in benzene and the uniform distribution of gaseous ethylene in corrugated plate channels.

The working process of dissolving ethylene in benzene and fully mixing is as follows:

the internal mixing member in the vertical ethylene-benzene mixer is a corrugated plate, the corrugated plate is arranged in the mixer in a sectional inclined manner, as shown in figure 1, after a certain distance, the installation direction of the corrugated plate is changed, and so on, and the space between the corrugated plates is a fluid channel.

Ethylene is distributed into the bottom of the inner mixing inner part in the inner mixer by the ethylene gas distributor, and the ethylene gas outlet of the gas distributor faces upwards or downwards, so that the high-speed gas is prevented from carrying liquid benzene to wash the side wall of the mixer and the wall of the mixer to cause damage. Let the gaseous evenly distributed of gas outlet of distribution go to in the buckled plate passageway simultaneously, at the in-process of flow through the buckled plate, ethylene gas dissolves to benzene to intensive mixing, the in-process of flow through the buckled plate, because the dissolution of ethylene, fluid volume flow reduces gradually.

The design is that a premixing absorption zone is arranged inside the mixer and is mainly completed in the mixing internal part, and a mixing zone is mainly completed in the mixing internal part. And a steady flow area is arranged between the premixing absorption area and the mixing absorption area, the steady flow area can be a part of the mixer, namely the mixer is lengthened for a certain length, and a pipeline with a certain length can also be used for realizing steady flow.

The ethylene gas entering the mixer is divided into 2 strands or a plurality of strands, the ethylene gas is dissolved into benzene in several times, the ethylene gas entering the premixing absorption area is dissolved into benzene, the volume change of the gas in the premixing area is reduced due to the reduction of the ethylene amount, and the volume flow change of the fluid is reduced due to the dissolution of the ethylene in the process of flowing through the corrugated plate. The disturbance to the mixed fluid is reduced, thereby achieving a reduction or elimination of vibration.

After the premixed mixture passes through the flow stabilizing section, ethylene required to be added is introduced into the gas distributor, the ethylene and the benzene are continuously mixed in the mixing zone, and similarly, because the amount of the gas ethylene is reduced, in the process of flowing through the corrugated plate, the volume flow variation of the fluid is reduced due to the dissolution of the ethylene, the disturbance on the mixed fluid is reduced, and the vibration is reduced or eliminated.

In this way, the mixing of ethylene and benzene is realized, and the vibration problem of the mixing system is solved.

The utility model has the advantages that:

1) The system vibration of a mixing absorption device in the ethylene-benzene mixing process is solved, and the safety risk is eliminated;

2) The ethylene is added into the benzene step by step for a plurality of times, the volume change of the mixed fluid is small, the mixing effect is good, the liquid phase and gas phase non-uniformity coefficient in the mixing process is less than or equal to 1-5%, and the outlet of the mixing device can ensure that the ethylene is completely liquefied and fully and uniformly dissolved into the benzene before entering the alkylation reactor.

Drawings

FIG. 1 is a diagram of a benzene and ethylene mixing apparatus for the liquid phase alkylation of benzene to ethylbenzene.

Wherein: 1-a raw material feed inlet; 2 premixing internal parts; 3-steady flow section, 4-gas distributor, 5-gas distributor, 6-mixing 7-discharge port and 8-ethylene.

Detailed Description

The present invention will be further explained with reference to the following embodiments, but the scope of the present invention is not limited thereto:

a mixing device for preparing ethylbenzene by liquid phase benzene alkylation is sequentially provided with a first gas distributor 4, a premixing internal member 2, a steady flow section 3, a second gas distributor 5 and a mixing internal member 6 from bottom to top, wherein the bottom of the device is provided with a raw material feeding hole 1, and the top of the device is provided with a discharging hole 7. The ethylene outlet lines are connected to a first gas distributor 4 and a second gas distributor 5, respectively. The premixing internals 2 and the mixing internals 6 are corrugated plates. The mixing device is of a vertical structure.

The internal mixing parts in the vertical ethylene-benzene mixer are corrugated plates and are arranged in the mixer, ethylene gas distributors 4 and 5 distribute ethylene into the bottoms of internal mixing parts 2 and 6 in the internal mixer, and an ethylene gas outlet of the gas distributor faces upwards or downwards, so that the phenomenon that high-speed gas carries liquid benzene to flush the side wall of the mixer and the wall of the mixer to cause damage is avoided.

The raw material inlet 1 enters a mixer from the bottom of a mixing device, firstly enters a premixing zone, is mixed with part of ethylene, enters a steady flow section 3, is continuously mixed with the ethylene in a mixing zone 6, fully absorbs and dissolves the ethylene, then enters a discharge port 7 to remove an alkylation reaction catalyst bed layer, and benzene and ethylene are alkylated to generate ethylbenzene.

This structural design allows a premixing absorption zone, which is predominantly implemented in the mixing internals 2, and a mixing zone, which is predominantly implemented in the mixing internals 6, to be present inside the mixer. And a steady flow zone 3 is arranged between the premixing absorption zone and the mixing absorption zone, the steady flow zone 3 can be a part of the mixer, namely the mixer is lengthened for a certain length, and a pipeline with a certain length can also be used for realizing steady flow.

The ethylene 8 entering the mixer is divided into 2 or more strands and dissolved into benzene in several times, the ethylene gas entering the premixing absorption zone is dissolved into benzene, and the volume change of the gas in the premixing zone is reduced due to the reduction of the ethylene amount, so that the disturbance to the mixed fluid is reduced, and the vibration is reduced or eliminated.

After the premixed mixture passes through the steady flow section 3, ethylene required to be added is introduced into the gas distributor 5, the ethylene-benzene remixing area is continuously mixed, and similarly, because the amount of the ethylene is reduced, the volume change of the gas in the mixing area is reduced, the disturbance to the mixed fluid is reduced, and the vibration is reduced or eliminated.

Through this kind of mode, realize the intensive mixing of ethylene and benzene, solve the vibration problem of hybrid system simultaneously, realize gaseous ethylene safe abundant evenly dissolving to benzene in.

Claims (4)

1. A mixing device for preparing ethylbenzene by liquid-phase benzene alkylation is characterized in that: the device is sequentially provided with a first gas distributor (4), a premixing internal part (2), a steady flow section (3), a second gas distributor (5) and a mixing internal part (6) from bottom to top, the bottom of the device is provided with a raw material inlet (1), and the top of the device is provided with a discharge hole (7).

2. The mixing apparatus for the liquid phase alkylation of benzene to ethylbenzene as claimed in claim 1, wherein: the ethylene input pipeline is respectively connected with the first gas distributor (4) and the second gas distributor (5).

3. The mixing apparatus for the liquid phase alkylation of benzene to ethylbenzene as claimed in claim 1, wherein: the premixing internals (2) and the mixing internals (6) are corrugated.

4. The mixing apparatus for the liquid phase alkylation of benzene to ethylbenzene of claim 1 wherein: the mixing device is of a vertical structure.

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