CN111558342A

CN111558342A - Gas-liquid mixing device

Info

Publication number: CN111558342A
Application number: CN202010448595.2A
Authority: CN
Inventors: 张国信; 李双权; 李群生; 苏月; 丁同银; 赵璐
Original assignee: China Petroleum and Chemical Corp; Sinopec Engineering Group Co Ltd; Sinopec Guangzhou Engineering Co Ltd
Current assignee: China Petroleum and Chemical Corp; Sinopec Engineering Group Co Ltd; Sinopec Guangzhou Engineering Co Ltd
Priority date: 2020-05-25
Filing date: 2020-05-25
Publication date: 2020-08-21

Abstract

The invention discloses a gas-liquid mixing device. The device comprises a shell, and a catalyst grid, a collecting disc, a cold hydrogen distributor, a bubble cap, a rough distribution disc, a gas-liquid distributor, a distribution disc and a redistribution disc which are arranged in the shell from top to bottom; wherein cold hydrogen distributor is through its open and the catch tray centre bore fixed connection of mixing chamber upper end, mainly comprises intake pipe, distribution ring canal, distribution straight tube, nozzle and mixing chamber, and the distribution ring canal uses the mixing chamber to be concentric circles form distribution as the center, and the distribution straight tube is alternately link up with the distribution ring canal, and the distribution straight tube all communicates with the mixing chamber lateral wall with the intake pipe. The invention has simple and compact structure, and is suitable for being used between catalyst beds of a large-diameter downflow reactor; the cold hydrogen can be distributed more uniformly on the whole cross section of the reactor, and can be fully mixed with reaction oil gas, thereby ensuring the uniform proceeding of mass transfer and heat transfer and improving the heat transfer efficiency of the medium in the reactor.

Description

Gas-liquid mixing device

Technical Field

The invention belongs to the field of petroleum processing, and relates to a gas-liquid mixing and distributing device for a hydrogenation reactor, in particular to a gas-liquid mixing device.

Background

In the hydrogenation process, because of the exothermic reaction of three phases of gas, liquid and solid, in order to make the reaction feed (gas phase and liquid phase) and the catalyst (solid phase) fully, uniformly and effectively contact, a hydrogenation reactor is generally designed with a plurality of catalyst beds, a distribution disc is arranged at the top of each bed, and a temperature control structure (cold hydrogen box) is arranged between the two beds so as to ensure the safe and stable production of a hydrogenation device and prolong the service life of the catalyst.

The hydrogenation reaction of hydrocarbons belongs to exothermic reaction, for the hydrogenation reactor with multiple beds, the temperature of oil gas and hydrogen will rise after the reaction in the previous bed, and cold hydrogen must be introduced between the two beds to control the temperature for the next bed to continue effective reaction. The tubes that introduce and distribute the cold hydrogen gas inside the reactor are called cold hydrogen tubes. The role and requirements of the cold hydrogen addition system are: uniformly and stably supplying enough cold hydrogen; the cold hydrogen must be thoroughly mixed with the hot reactants and have a uniform temperature and material distribution on entering the next bed. The cold hydrogen pipe is divided into a direct insertion type, a dendritic type and a ring structure according to the form.

The cold hydrogen tank is a combination of a mixing tank and a pre-distribution plate. It is the place where the hot reactant and cold hydrogen in the hydrogenation reactor are mixed and heat exchanged. The reaction product flowing down from the upper layer and the cold hydrogen injected from the cold hydrogen pipe are fully mixed in the box to absorb the reaction heat, reduce the temperature of the reactant, meet the reaction requirement of the next catalyst bed layer and avoid the over-temperature of the reactor.

The first layer of the cold hydrogen box is a baffle plate disk, and the baffle plate is provided with a throttling hole. The cold hydrogen from the cold hydrogen pipe and the oil gas after the reaction of the previous bed layer are premixed on the baffle disc and then enter the cold hydrogen box through the throttling hole. Cold hydrogen entering the cold hydrogen box and hot oil gas from the upper layer are repeatedly baffled and mixed, then flow to the second layer of the cold hydrogen box, namely the sieve plate disc, and are baffled again on the sieve plate disc to strengthen the mixing effect, and then are distributed. And a layer of redistributing tray is arranged below the sieve tray to redistribute the oil gas after the predistribution.

The redistributing tray consists of a tray plate and distributors uniformly distributed on the tray plate. The redistribution plate is arranged on the catalyst bed layer, and aims to uniformly distribute the reaction medium, improve the flow condition of the reaction medium, realize good contact with the catalyst and further achieve uniform distribution in the radial direction and the axial direction. The types of distributors are more, and the hydrogenation reactors designed and manufactured by China mostly adopt bubble cap type distributors.

Patent CN201620014039.3 discloses a mixing system comprising: the catalyst comprises a shell, an upper catalyst layer, a lower catalyst layer and a hydrogenation pipe; the upper catalyst layer and the lower catalyst layer are arranged in the shell at intervals from top to bottom, and a mixing cavity is formed between the upper catalyst layer and the lower catalyst layer; one end of the hydrogenation pipe is arranged in the mixing cavity; the side wall of the hydrogenation pipe is provided with a plurality of air outlets. Cold hydrogen flows into the mixing cavity from the plurality of air outlets, the reaction fluid can be fully mixed with the cold hydrogen when flowing into the mixing cavity, and the reaction fluid and the cold hydrogen can be fully mixed when the hydrogenation pipe is introduced with the cold hydrogen, so that the space of the mixing cavity is reduced, but the heat transfer and mass transfer are not uniform enough, and the reaction is not stable enough.

At present, with the upsizing of a hydrogenation device and the development of a new hydrogenation technology, the diameter of a hydrogenation reactor is larger and larger, and the catalyst bed layer of a single hydrogenation reactor is increased. After the hydrogenation reactor is enlarged, the advanced applicability of the inner member becomes more important, and how to realize the uniform distribution of the gas-liquid two-phase fluid in the bed layer, ensure the uniform proceeding of mass transfer and heat transfer and improve the heat transfer efficiency of the medium in the reactor becomes more difficult and more important. For example, the foreign advanced gas-liquid distributor is combined with the advanced catalyst filling technology to ensure that the temperature on the inner section of the reactor is very uniform, and the temperature difference reaches the level of less than or equal to 1 ℃, thereby being beneficial to the operation control of the reactor and greatly prolonging the service life of the catalyst.

Disclosure of Invention

The invention provides a gas-liquid mixing device, aiming at solving the technical problems that gas-liquid two-phase fluid is difficult to be uniformly distributed in a catalyst bed layer, the mass and heat transfer is not uniform enough and the heat transfer efficiency is low in the prior art.

The device comprises a shell, and a catalyst grid, a collecting disc, a cold hydrogen distributor, a gas-liquid distributor and a distributing disc which are arranged in the shell from top to bottom; the gas-liquid distributor is vertically fixed on the distribution disc, and the catalyst grid, the collection disc and the distribution disc are all fixed on the inner wall of the shell.

As an improved scheme, a rough distribution disc is arranged in the space inside the shell below the cold hydrogen distributor and above the gas-liquid distributor, liquid distribution holes are uniformly distributed in the rough distribution disc, and a bubble cap can be further arranged on the rough distribution disc.

As a further improved scheme, a disc-shaped redistribution disc is arranged below the distribution disc, and holes are uniformly distributed in the redistribution disc.

The cold hydrogen distributor mainly comprises an air inlet pipe, a distribution ring pipe, a distribution straight pipe, a nozzle and a mixing chamber, wherein the air inlet pipe, the distribution ring pipe, the distribution straight pipe and the mixing chamber are all positioned in the same plane; one end of the air inlet pipe is a cold hydrogen inlet, and the other end of the air inlet pipe is communicated with the side wall of the mixing chamber; the distribution ring pipe is in a semi-arc shape with two closed ends and is distributed in a concentric circle shape by taking the mixing chamber as the center; the mixing chamber is a cylindrical body with an open upper end and a closed bottom; the distribution straight pipe is communicated with the distribution ring pipe in a crossed manner, one end of the distribution straight pipe is communicated with the side wall of the mixing chamber, and the other end of the distribution straight pipe is communicated with the distribution ring pipe; the distribution ring pipe and the distribution straight pipe are provided with obliquely downward nozzles arranged in pairs at intervals along the axis, and each nozzle is a cold hydrogen outlet; and bent nozzles with horizontal section ports and spray holes which are obliquely downward and face the center of the reactor and are obliquely downward and face the inner wall of the reactor are arranged on the outer ring pipe of the distribution ring pipe at intervals along the axis, each bent nozzle and spray hole are cold hydrogen outlets, and the cold hydrogen distributor is fixedly connected with the central hole of the collecting tray through an opening at the upper end of a mixing chamber of the cold hydrogen distributor.

The two nozzles arranged in pairs are arranged in an axial symmetry mode, and each nozzle and the horizontal plane form an angle of 30-60 degrees.

The bent nozzles and the spray holes which are arranged on the outer ring pipe are arranged in axial symmetry, and form an angle of 30-60 degrees with the horizontal plane respectively.

As the improved scheme, the end part of each nozzle is provided with a contraction hole, the end part close to the nozzle is uniformly provided with injection holes along the circumferential direction, and the number of the injection holes is 2-8 so as to ensure the uniform distribution of cold hydrogen.

As a further improvement scheme, a mixing chamber distribution plate is arranged on the inner wall of the mixing chamber close to the upper end opening, and liquid distribution holes are uniformly distributed on the mixing chamber distribution plate.

The working principle of the gas-liquid mixing device provided by the invention is as follows:

the oil gas reacted by the upper catalyst bed layer flows downwards through the catalyst grating,

collecting the mixture by a collecting disc and entering a mixing chamber; in order to meet the requirement of the next bed layer for continuous effective reaction, cold hydrogen is introduced between the two bed layers to control the temperature, the cold hydrogen enters a mixing chamber through an air inlet pipe of a cold hydrogen distributor to be mixed with reaction oil gas, the cold hydrogen mixed with the reaction oil gas is obliquely sprayed downwards through nozzles on a distribution straight pipe and a distribution ring pipe to enter a bed layer space, the cold hydrogen is uniformly distributed in the radial direction and the circumferential direction of the whole cross section of the reactor, the cold hydrogen continues to further be mixed and distributed downwards through a coarse distribution plate and a bubble cap, the oil gas mixed and distributed by the coarse distribution plate enters a distribution plate and a gas-liquid distributor below the oil gas to be distributed again, dead zones are reduced, the oil gas is distributed more uniformly on the whole cross section of the reactor, and the next bed layer reaction is.

The invention has the following beneficial effects:

1) the unique structure of the cold hydrogen distributor ensures that the cold hydrogen is more uniformly distributed on the whole cross section of the reactor and can be fully mixed with reaction oil gas, thereby ensuring the uniform proceeding of mass transfer and heat transfer and improving the heat transfer efficiency of the medium in the reactor;

2) the cold hydrogen distributor consists of an air inlet pipe, a distribution straight pipe, a distribution ring pipe, a mixing chamber and a nozzle, has simple and compact structure, can greatly save the investment of the reactor, is more convenient to install and disassemble, and is suitable for being used between catalyst beds of a large-diameter downflow reactor.

3) The arrangement of the rough distribution plate and the redistribution plate ensures that reaction oil gas is fully mixed and distributed before being mixed and distributed by the gas-liquid distributor, so that subsequent mixing and distribution are more thorough and uniform, the reaction is more stable, and the operation of the reactor is easier to control.

Drawings

FIG. 1 is a schematic diagram of one configuration of a cold hydrogen distributor of the present invention;

FIG. 2 is a schematic view of another configuration of the cold hydrogen distributor of the present invention;

FIG. 3 is a schematic view of the structure of FIG. 1 and FIG. 2 in the direction A-A;

FIG. 4 is a schematic structural view of the nozzle of FIG. 3;

FIG. 5 is a schematic view of the structure in the direction B-B in FIG. 2;

FIG. 6 is a schematic view of the structure of the gas-liquid mixing device of the present invention;

FIG. 7 is a schematic view of the assembled structure of the mixing chamber and the collecting tray;

FIG. 8 is a schematic view of the construction of the distribution plate of the mixing chamber;

FIG. 9 is a schematic view of the distribution of bubble caps on the rough dispensing pan;

figure 10 is a schematic view of a dispensing hole in a dispensing disc.

In the figure: 1-gas inlet pipe, 2-straight distribution pipe, 3-circular distribution pipe, 4-mixing chamber, 5-cold hydrogen inlet, 6-nozzle, 7-contraction hole, 8-injection hole, 9-bent nozzle, 10-injection hole, 11-shell, 12-catalyst grid, 13-catalyst grid support beam, 14-cold hydrogen distributor, 15-collection tray, 16-cold hydrogen distributor support beam, 17-bubble cap, 18-rough distribution tray, 19-gas-liquid distributor, 20-distribution tray, 21-rough distribution tray support beam, 22-redistribution tray, 23-catalyst bed, 24-mixing chamber distribution plate, 25-liquid distribution hole, 26-liquid distribution hole and 27-distribution hole.

Detailed Description

The invention is further described below with reference to the accompanying drawings.

As shown in fig. 1 to 5, the cold hydrogen distributor of the present invention includes an air inlet pipe 1, a distribution ring pipe 3, a distribution straight pipe 2, a nozzle 6 and a mixing chamber 4, wherein the air inlet pipe 1, the distribution ring pipe 3, the distribution straight pipe 2 and the mixing chamber 4 are all located in the same plane; the distribution ring pipe 3 is in a semi-arc shape with two closed ends and is distributed in a concentric circle shape by taking the mixing chamber 4 as the center; the mixing chamber 4 is a cylinder with an open upper end and a closed bottom; the distribution straight pipe 2 is communicated with the distribution ring pipe 3 in a crossed manner, one end of the distribution straight pipe 2 is communicated with the side wall of the mixing chamber 4, and the other end of the distribution straight pipe is communicated with the distribution ring pipe 3; the distribution ring pipe 3 and the distribution straight pipe 2 are provided with nozzles 6 which are arranged in pairs at intervals along the axial line, each nozzle 6 is a cold hydrogen outlet, when the cold hydrogen distributor adopts the structure shown in the figure 2, bent nozzles 9 which are inclined downwards and face the center of the reactor and spray holes 10 which are inclined downwards and face the inner wall of the reactor are arranged on the outer ring pipe in the distribution ring pipe 3 at intervals along the axial line, and the bent nozzles 9 and the spray holes 10 are cold hydrogen outlets; one end of the air inlet pipe 1 is a cold hydrogen inlet 5, and the other end of the air inlet pipe 1 is communicated with the side wall of the mixing chamber 4. Two nozzles 6 arranged in pairs in fig. 3 are arranged in axial symmetry, and each nozzle forms an angle of 30-60 degrees with the horizontal plane. The end of the nozzle in the figure 4 is provided with a contraction hole 7, the end close to the nozzle is uniformly provided with jet holes 8 along the circumferential direction, the number of the jet holes 8 is 2-8, and the bent nozzle 9 in the figure 5 is a bent nozzle with a horizontal section port so as to ensure the uniform distribution of cold hydrogen.

As shown in fig. 6, the gas-liquid mixing device of the present invention includes a housing 11, a catalyst grid 12 fixed on the inner wall of the housing 11 and on a catalyst grid support beam 13, a collecting tray 15 fixed on the inner wall of the housing 11 and under the catalyst grid 12, a cold hydrogen distributor 14 fixed under the collecting tray 15 by a cold hydrogen distributor support beam 16, a bubble cap 17 fixed on a rough distribution tray 18 and under the cold hydrogen distributor 14, and a gas-liquid distributor 19 fixed on a distribution tray 20 and under the rough distribution tray 18. The coarse distribution plate support beam 21 connects and supports the coarse distribution plate 18, the distribution plate 20 and the redistribution plate 22, the catalyst bed layer 23 is below the distribution plate 20, and the distribution plate 20 and the redistribution plate 22 are fixed on the inner wall of the shell 11.

Fig. 7 shows a schematic view of the assembly of the mixing chamber 4 and the collecting tray 15, a mixing chamber distribution plate 24 is provided in the mixing chamber 4 near the upper end opening, and the mixing chamber distribution plate 24 is schematically shown in fig. 8, and is provided with liquid distribution holes 25.

Fig. 9 shows a schematic view of the distribution of the bubble cap 17 and the liquid dispensing apertures 26 on the rough dispensing disc.

The working principle of the invention is explained below with reference to the drawings:

the reaction oil gas of the upper catalyst bed layer flows downwards through the catalyst grid 12, is collected by the collecting tray 15 and enters the mixing chamber 4 through the mixing chamber distribution plate 24; in order to meet the requirement of the next bed layer for continuous effective reaction, cold hydrogen is introduced between the two bed layers to control the temperature, the cold hydrogen enters a mixing chamber 4 through a cold hydrogen inlet 5 and is mixed with reaction oil gas through an air inlet pipe 1, the cold hydrogen mixed with the reaction oil gas is obliquely sprayed downwards through nozzles on a distribution straight pipe 2 and a distribution ring pipe 3 and enters a bed layer space, the cold hydrogen is uniformly distributed in the radial direction and the circumferential direction of the whole cross section of the reactor, and the cold hydrogen continuously downwards enters a distribution plate 20, a gas-liquid distributor 19 and a redistribution plate 22 below after further mixing and distribution of a rough distribution plate 18 and a bubble cap 17 to be distributed again, so that dead zones are reduced, the oil gas is distributed more uniformly on the whole cross section of the reactor, and the reaction of the next catalyst bed layer 23 is more.

Claims

1. A gas-liquid mixing device is characterized in that: the device comprises a shell, and a catalyst grid, a collecting disc, a cold hydrogen distributor, a gas-liquid distributor, a distributing disc and a redistributing disc which are arranged in the shell from top to bottom; the gas-liquid distributor is vertically fixed on the distribution plate, a disc-shaped redistribution plate is arranged below the distribution plate, and holes are uniformly distributed on the redistribution plate; the catalyst grating, the collecting tray, the distributing tray and the redistributing tray are all fixed on the inner wall of the shell; the cold hydrogen distributor mainly comprises an air inlet pipe, a distribution ring pipe, a distribution straight pipe, a nozzle and a mixing chamber, wherein the air inlet pipe, the distribution ring pipe, the distribution straight pipe and the mixing chamber are all positioned in the same plane; one end of the air inlet pipe is a cold hydrogen inlet, and the other end of the air inlet pipe is communicated with the side wall of the mixing chamber; the distribution ring pipe is in a semicircular arc shape with two closed ends and is distributed in a concentric circle shape by taking the mixing chamber as the center; the mixing chamber is a cylindrical body with an open upper end and a closed bottom; a mixing chamber distribution plate is arranged on the inner wall of the mixing chamber close to the upper end opening, and liquid distribution holes are uniformly distributed on the mixing chamber distribution plate; the distribution straight pipe is communicated with the distribution ring pipe in a crossed manner, one end of the distribution straight pipe is communicated with the side wall of the mixing chamber, and the other end of the distribution straight pipe is communicated with the distribution ring pipe; the distribution ring pipe and the distribution straight pipe are provided with obliquely downward spray holes which are arranged in pairs at intervals along the axis, and each spray hole is a cold hydrogen outlet; the cold hydrogen distributor is fixedly connected with the central hole of the collecting disc through an opening at the upper end of the mixing chamber.

2. The gas-liquid mixing device according to claim 1, characterized in that: and a coarse distribution disc is arranged in the space in the shell below the cold hydrogen distributor and above the gas-liquid distributor, and liquid distribution holes are uniformly distributed in the coarse distribution disc.

3. The gas-liquid mixing device according to claim 2, characterized in that: and a bubble cap is arranged on the rough distribution disc.

4. The gas-liquid mixing device according to claim 1, characterized in that: and bent nozzles which are obliquely downward and face the center of the reactor and are provided with horizontal section ports and spray holes which are obliquely downward and face the inner wall of the reactor are arranged on the outer ring pipe of the distribution ring pipe at intervals along the axis, and each bent nozzle and each spray hole are cold hydrogen outlets.

5. The gas-liquid mixing device according to claim 4, characterized in that: the bent nozzles and the spray holes which are arranged on the outer ring pipe are arranged in axial symmetry, and form an angle of 30-60 degrees with the horizontal plane respectively.

6. The gas-liquid mixing device according to claim 1, characterized in that: the distribution ring pipe and the distribution straight pipe are provided with obliquely downward nozzles arranged in pairs at intervals along the axis, and each nozzle forms an angle of 30-60 degrees with the horizontal plane.

7. The gas-liquid mixing device according to claim 1, characterized in that: the distribution ring pipe is composed of an inner ring pipe and an outer ring pipe, two nozzles arranged in pairs on the inner ring pipe are arranged in an axial symmetry mode, each nozzle is at an angle of 30-60 degrees with the horizontal plane, and a bent nozzle arranged on the spray hole outer ring pipe is arranged in an axial symmetry mode with the spray holes and is at an angle of 30-60 degrees with the horizontal plane.

8. The gas-liquid mixing device according to claim 6 or 7, characterized in that: the tip of nozzle is equipped with the shrinkage cavity, and the quantity of jet orifice is 2 ~ 8.