CN109536203B

CN109536203B - Catalytic light gasoline etherification device and method

Info

Publication number: CN109536203B
Application number: CN201810170724.9A
Authority: CN
Inventors: 刘成军; 温世昌; 李倞琛; 周璇; 赵霞
Original assignee: China National Petroleum Corp; CNPC EastChina Design Institute Co Ltd
Current assignee: China National Petroleum Corp; CNPC EastChina Design Institute Co Ltd
Priority date: 2018-03-01
Filing date: 2018-03-01
Publication date: 2020-11-03
Anticipated expiration: 2038-03-01
Also published as: CN109536203A

Abstract

The invention discloses a catalytic light gasoline etherification device and method, and belongs to the field of petrochemical industry. The device comprises: the first reaction section, the heat exchange section and the second reaction section are sequentially arranged from top to bottom; the heat exchange section is used for preheating the etherification raw materials and cooling the primary etherification products from the first reaction section; the first reaction section is used for reacting the preheated etherification raw materials to generate a first-order etherification product; the second reaction section is used for reacting the cooled first-stage etherification product to generate a second-stage etherification product. The invention can realize the etherification treatment of the catalytic light gasoline only through the cooperation of the first reaction section, the heat exchange section and the second reaction section, avoids additionally using equipment such as a heater, a cooler and the like, saves the equipment cost and the operation cost, reduces the energy consumption and reduces the occupied area.

Description

Catalytic light gasoline etherification device and method

Technical Field

The invention relates to the field of petrochemical industry, in particular to a catalytic light gasoline etherification device and a catalytic light gasoline etherification method.

Background

Catalytic light gasoline is one of the products of petroleum catalytic cracking and is commonly used for preparing motor gasoline. However, catalytic light gasoline contains a large amount of C₄～C₆Olefins, which not only affect their performance properties, but also nitrogen dioxide (NO) in the sun and in the exhaust gases of motor vehicles₂) Photochemical smog which is diffused in the troposphere is generated, and environmental pollution is caused. At present, methanol or ethanol is generally adopted to catalyze C in light gasoline₄～C₆The olefin is etherified to reduce the olefin content, improve the octane number and oxygen content of the gasoline, enhance the stability of the gasoline and reduce the vapor pressure of the gasoline. Based on the above, it is necessary to provide a catalytic light gasoline etherification device.

The prior art provides a catalytic light gasoline etherification device, as shown in fig. 1, the device includes: according toA raw material preheater A, a first etherification reactor B, a cooler C and a second etherification reactor D which are communicated in sequence in the liquid flowing direction. The first etherification reactor B is used for improving the reaction rate of the etherification reaction in a high-temperature state, and the second etherification reactor D is used for improving the C content in the catalytic light gasoline in a low-temperature state₄～C₆Conversion of olefins. When the catalyst is used, an etherification raw material consisting of catalytic light gasoline and methanol or ethanol enters a raw material preheater A for preheating; feeding the preheated etherification raw material into a first etherification reactor B to generate a first-stage etherification product; cooling the first-stage etherification product in a cooler C; and (4) feeding the cooled first-stage etherification product into a second etherification reactor D to generate a second-stage etherification product, and discharging.

The inventor finds that the prior art has at least the following problems:

the catalytic light gasoline etherification device provided by the prior art comprises four devices, and increases the equipment cost, the operation cost, the device energy consumption and the occupied area.

Disclosure of Invention

The embodiment of the invention provides a catalytic light gasoline etherification device and a catalytic light gasoline etherification method, which can solve the technical problems. The technical scheme is as follows:

in one aspect, a catalytic light gasoline etherification unit is provided, the unit comprising: the first reaction section, the heat exchange section and the second reaction section are sequentially arranged from top to bottom;

the heat exchange section is used for preheating etherification raw materials and cooling first-stage etherification products from the first reaction section;

the first reaction section is used for reacting the preheated etherification raw materials to generate a first-order etherification product;

and the second reaction section is used for reacting the cooled first-stage etherification product to generate a second-stage etherification product.

In one possible design, the first reaction stage includes: an upper shell with a closed top and a first catalyst bed layer;

the first catalyst bed is disposed within the upper shell.

In one possible design, the first reaction stage further comprises: the feeding distributor is communicated with the heat exchange section and is used for distributing the preheated etherification raw materials;

the feeding distributor is arranged in the upper shell and is positioned above the first catalyst bed layer.

In one possible design, the feed distributor comprises: a main pipe, a plurality of branch pipes;

the branch pipes are communicated with the main pipe and are arranged at intervals along the axial direction of the main pipe;

the branch pipe is provided with a plurality of fluid through holes, and two ports of the branch pipe are closed;

one port of the main pipe is closed, and the other port of the main pipe is communicated with the heat exchange section.

In one possible design, the heat exchange section comprises: the device comprises a middle shell, an upper partition plate, a lower partition plate and a plurality of heat exchange tubes for conveying the first-stage etherification products;

a shell pass inlet and a shell pass outlet are formed in the wall of the middle shell, and the shell pass outlet is communicated with the other port of the main pipe through an outer pipe;

the upper partition plate and the lower partition plate are respectively arranged at the upper end and the lower end of the middle shell;

the heat exchange tubes are vertically arranged between the upper partition plate and the lower partition plate, and the upper end port and the lower end port of the heat exchange tubes are respectively communicated with the first reaction section and the second reaction section.

In one possible design, the heat exchange section further comprises: a plurality of first screens, a plurality of second screens;

the first screen is arranged on the upper partition plate and is communicated with the upper port of the corresponding heat exchange tube;

the second screen is arranged on the lower partition plate and communicated with the corresponding lower port of the heat exchange tube.

In one possible design, the second reaction stage includes: a lower shell and a second catalyst bed layer;

the second catalyst bed layer is arranged in the lower shell;

the bottom of the lower shell is provided with a discharge hole, and the top of the lower shell is communicated with the middle shell.

In one possible design, a third screen is arranged at the discharge opening.

In one possible design, a plurality of inert ceramic balls are filled between the second catalyst bed and the third screen.

In another aspect, a catalytic light gasoline etherification process is provided, the process comprising:

conveying an etherification raw material into a heat exchange section, and carrying out heat exchange on the etherification raw material and a primary etherification product from a first reaction section to preheat the etherification raw material and simultaneously cool the primary etherification product;

utilizing the first reaction section to generate a first-stage etherification product from the preheated etherification raw material;

and utilizing the second reaction section to generate a secondary etherification product from the cooled primary etherification product, and discharging the secondary etherification product.

The technical scheme provided by the embodiment of the invention has the following beneficial effects:

according to the catalytic light gasoline etherification device provided by the embodiment of the invention, an etherification raw material is preheated through the heat exchange section, a previous round of first-order etherification product from the first reaction section is cooled, the preheated etherification raw material is enabled to generate a current round of first-order etherification product through the first reaction section, and the cooled current round of first-order etherification product is enabled to generate a second-order etherification product through the second reaction section, so that the device not only has the function of converting the etherification raw material into the first-order etherification product and the second-order etherification product, but also has the functions of preheating the etherification raw material and cooling the first-order etherification product. Therefore, the device can realize etherification treatment on the catalytic light gasoline only through the cooperation of the first reaction section, the heat exchange section and the second reaction section, avoids additional use of equipment such as a heater and a cooler, saves equipment cost and operation cost, reduces energy consumption and reduces occupied area.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the description of the embodiments will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.

FIG. 1 is a schematic diagram of a prior art catalytic light gasoline etherification unit;

FIG. 2 is a schematic structural diagram of a catalytic light gasoline etherification device provided by the embodiment of the invention;

FIG. 3 is a schematic diagram of a feed distributor according to an embodiment of the present invention;

FIG. 4 is a top view of a heat exchange section provided by an embodiment of the present invention;

FIG. 5a is a schematic view of the installation of the upper and lower partitions on the middle housing according to the embodiment of the present invention;

FIG. 5b is another schematic view of the upper and lower partitions mounted on the middle housing according to the present invention;

FIG. 6 is an enlarged, fragmentary schematic view of a heat exchange section provided in accordance with an embodiment of the present invention;

FIG. 7 is a schematic enlarged view of a portion of a second reaction zone provided in an embodiment of the present invention.

The reference numerals denote:

a-a raw material preheater;

b-a first etherification reactor;

a C-cooler;

d-a second etherification reactor;

1-a first reaction section;

101-an upper shell;

102-a first catalyst bed;

103-a feed distributor;

103 a-main tube;

103 b-branch pipe;

103 c-a first fixing plate;

103 d-a second fixation plate;

103 e-third fixing plate

103 f-connector;

2-a heat exchange section;

201-middle shell;

201 a-shell side inlet;

201 b-shell side outlet;

202-upper baffle plate;

203-lower baffle plate;

204-heat exchange tube;

205-an outer tube;

206-a first screen;

206 a-a frame;

206 b-screen bars;

206 c-cover plate;

207-a second screen;

208 a-an upper stop;

208 b-a lower retainer;

209 a-first seal ring;

209 b-a second seal ring;

2010 a-first circlip;

2010 b-a second circlip;

2011 a-third seal ring;

2011 b-fourth seal ring;

2012-a first connector;

2012 a-support plate;

2012 b-a stud;

2012 c-nut;

2012 d-gasket;

3-a second reaction section;

3 a-a discharge hole;

301-a lower housing;

302-a second catalyst bed;

303-a third screen;

303 a-cylinder;

303 b-top plate;

304-inert ceramic balls;

305-a second connector;

305 a-a backing plate;

305 b-a tubular body.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

In the embodiment of the present invention, the etherification feedstock refers to a mixture of catalytic light gasoline and methanol or ethanol. Catalyzing C in light gasoline₄～C₆The etherification reaction of an olefin with methanol or ethanol is a reversible, exothermic reaction that proceeds in the liquid phase. Wherein, the rate constants of the forward reaction and the reverse reaction increase along with the increase of the temperature, but the rate constant increase amplitude of the reverse reaction is larger than that of the forward reaction, so that before etherification treatment of the etherification raw material, the etherification raw material needs to be preheated to improve the forward reaction rate; after the etherification reaction reaches the equilibrium, the etherification raw material and the ether compound (namely the first-order etherification product) are cooled, and then the first-order etherification product is continuously etherified so as to improve the C content in the etherification raw material₄～C₆Conversion of olefins.

In addition, the first-order etherification product and the second-order etherification product related to the embodiment of the invention have the same components and both comprise the etherification raw materials and the ether compounds, but the content of the ether compounds of the second-order etherification product is greater than that of the first-order etherification product.

In a first aspect, an embodiment of the present invention provides a catalytic light gasoline etherification apparatus, as shown in fig. 2, the apparatus includes: the first reaction section 1, the heat exchange section 2 and the second reaction section 3 are arranged from top to bottom in sequence; the heat exchange section 2 is used for preheating the etherification raw materials and cooling the first-stage etherification products from the first reaction section 1; the first reaction section 1 is used for reacting the preheated etherification raw materials to generate a first-order etherification product; the second reaction section 3 is used for reacting the cooled first-order etherification product to generate a second-order etherification product.

It should be noted that the first reaction section 1, the heat exchange section 2 and the second reaction section 3 are sequentially communicated from top to bottom.

The following description is given of the working principle and effects of the catalytic light gasoline etherification device provided by the embodiment of the invention:

when the device is used, the etherification raw materials are conveyed into the heat exchange section 2, and the etherification raw materials and the first-stage etherification products of the previous round (namely the first-stage etherification products from the first reaction section 1) are subjected to heat exchange in the heat exchange section 2 to preheat the etherification raw materials and cool the first-stage etherification products of the previous round.

The preheated etherification raw material enters the first reaction section 1 to carry out etherification reaction to generate the first-stage etherification product of the current round. After the etherification reaction reaches the equilibrium, the first-stage etherification product of the current round enters the heat exchange section 2 and exchanges heat with the etherification raw material of the next round, thereby reducing the temperature of the etherification raw material.

And (3) feeding the cooled first-stage etherification product of the current round into a second reaction section 3, further carrying out etherification reaction to generate a second-stage etherification product, and discharging the second-stage etherification product from the second reaction section 3 after the etherification reaction reaches balance.

According to the catalytic light gasoline etherification device provided by the embodiment of the invention, an etherification raw material is preheated through the heat exchange section 2, a previous round of first-order etherification product from the first reaction section 1 is cooled, the preheated etherification raw material is enabled to generate a current round of first-order etherification product through the first reaction section 1, and the cooled current round of first-order etherification product is enabled to generate a second-order etherification product through the second reaction section 3, so that the device not only has the function of converting the etherification raw material into the first-order etherification product and the second-order etherification product, but also has the functions of preheating the etherification raw material and cooling the first-order etherification product. Therefore, the device can realize etherification treatment on the catalytic light gasoline only through the cooperation of the first reaction section 1, the heat exchange section 2 and the second reaction section 3, avoids additional use of equipment such as a heater, a cooler and the like, saves equipment cost and operation cost, reduces energy consumption and reduces occupied area.

The first reaction section 1 may be configured in various structures, as long as the preheated etherification raw material reacts to generate a first-order etherification product, and the first-order etherification product can be ensured to enter the heat exchange section 2, for example, as shown in fig. 2, the first reaction section 1 includes: an upper shell 101 with a closed top, a first catalyst bed layer 102; a first catalyst bed 102 is disposed within the upper housing 101.

The first reaction section 1 is simple in structure and convenient to produce and process.

The upper housing 101 may have various structures, for example, it may be formed by welding a spherical end socket and a cylinder.

Alternatively, the first catalyst bed 102 may be disposed on the inner wall of the upper shell 101 through a grid plate, or may be directly stacked on the top of the heat exchange section 2, i.e., the bottom of the first reaction section 1 (see fig. 2). In order to save processing costs, the latter embodiment is preferred in embodiments of the present invention, which may avoid installing a grid plate in the upper housing 101.

To reduce the cost of the formation of the first-stage etherification product, the catalyst particles in the first catalyst bed 102 may be selected from cation exchange resins. The catalyst is convenient to prepare and obtain, and has a good catalytic effect.

The ratio of the height of the first catalyst bed 102 to the inner diameter of the upper housing 101 may be set to 3 to 8, for example, the ratio may be set to 3, 4, 5, 6, 7, 8, etc. By such an arrangement, the etherification raw material entering the first catalyst bed 102 can be effectively subjected to etherification treatment, and the waste of the catalyst can be avoided.

Further, in order to uniformly distribute the preheated etherification raw material on the top of the first catalyst bed 102 and improve the utilization rate of the first catalyst bed 102, in the embodiment of the present invention, as shown in fig. 2, the first reaction section 1 further includes: a feeding distributor 103 which is communicated with the heat exchange section 2 and is used for distributing the preheated etherification raw materials; a feed distributor 103 is disposed within the upper housing 101 and above the first catalyst bed 102.

Wherein, the installation position of the feeding distributor 103 in the upper shell 101 can be set as follows: is positioned 300 mm-500 mm (300 mm, 400mm, 500mm, etc.) below the welding line of the end socket and the cylinder in the upper shell 101, and is positioned 800 mm-1000 mm (800 mm, 900mm, 1000mm, etc.) above the first catalyst bed layer 102. Through such an arrangement, the impact of the preheated etherification raw material on the first catalyst bed layer 102 can be reduced, and the preheated etherification raw material can enter the first catalyst bed layer 102.

Further, based on the simple structure, as shown in fig. 3, the feeding distributor 103 includes: a main pipe 103a, a plurality of branch pipes 103 b; the branch pipes 103b are communicated with the main pipe 103a and are arranged at intervals along the axial direction of the main pipe 103 a; a plurality of fluid through holes are formed in the branch pipe 103b, and two ports are closed; one port of the main tube 103a is closed and the other port communicates with the heat exchange section 2.

Through the arrangement, the preheated etherification raw material from the heat exchange section 2 firstly enters the main pipe 103a through the other port of the main pipe 103a and then falls into the top of the first catalyst bed layer 102 through the fluid through holes of the plurality of branch pipes 103b, which is beneficial to the uniform distribution of the etherification raw material on the top of the first catalyst bed layer 102 and can improve the reaction conversion rate of the etherification raw material in the first catalyst bed layer 102.

Wherein the fluid through holes may be provided on the upper side wall or/and the lower side wall of the branch pipe 103 b. In the embodiment of the present invention, the fluid through holes are formed in the lower side walls of the branch pipes 103b, so that the preheated etherification raw material can flow into the first catalyst bed 102, and the processing of the branch pipes 103b is facilitated.

The fluid through holes may have a hole diameter of 3mm to 8mm (e.g., 3mm, 4mm, 5mm, 6mm, 7mm, 8mm, etc.), and are uniformly distributed in the inner cavity of the upper casing 101 at 150 to 250 (e.g., 150, 170, 190, 210, 230, 250, etc.) per square cross-sectional area. By such an arrangement, the strength of the branch pipe 103b can be ensured, and the etherification raw material can be made to flow uniformly into the first catalyst bed 102.

In the embodiment of the present invention, one port of the main pipe 103a may be disposed in the upper case 101 through the first fixing plate 103c (see fig. 3). Wherein the first fixing plate 103c may be welded to the inner wall of the upper case 101 or bolted to the lug plate welded to the inner wall of the upper case 101.

As for the connection manner of the main pipe 103a and the first fixing plate 103c, there may be provided various manners, for example, one port of the main pipe 103a may be fixed on the first fixing plate 103c by a wire or a metal strip winding manner; or, two clamping plates are vertically arranged on the first fixing plate 103c, one port of the main pipe 103a is positioned between the two clamping plates, and a fastening bolt is transversely inserted into the upper parts of the two clamping plates, so that the fastening bolt is abutted against the top of the main pipe 103 a; further alternatively, the first fixing plate 103c is fixed thereto by a U-bolt.

The three connection modes are convenient for the disassembly and assembly of the main pipe 103a, and can be selected according to specific conditions during implementation. It is understood that the main pipe 103a may be installed on an upper surface or a lower surface of the first fixing plate 103c, for example, on an upper surface in an embodiment of the present invention (see fig. 3).

Similarly, in the embodiment of the present invention, the two ports of the plurality of branch pipes 103b may be fixed in the upper housing 101 by the second fixing plate 103d and the third fixing plate 103e, respectively (see fig. 3). The second fixing plate 103d and the third fixing plate 103e may be welded to the inner wall of the upper casing 101, or may be bolted to lug plates welded to the inner wall of the upper casing 101.

The connection between the two ports of the branch pipe 103b and the second and

third fixing plates

103d and 103e may be the same as the connection between the main pipe 103a and the first fixing plate 103 c. It is understood that the two ports of the branch pipe 103b can be respectively mounted on the top wall or the bottom wall of the second fixing plate 103d and the third fixing plate 103e, for example, on the lower surface in the embodiment of the present invention (see fig. 3).

In order to facilitate the replacement of the main pipe 103a and the branch pipes 103b, as shown in fig. 3, the feeding distributor 103 further includes: a plurality of groups of connectors 103f, wherein each group of connectors 103f is composed of two connectors 103f symmetrically arranged on the main pipe 103 a; the plurality of groups of connectors 103f are all communicated with the main pipe 103a and are distributed at intervals along the axial direction of the main pipe 103 a; the branch pipe 103b comprises a first branch pipe and a second branch pipe, and the first branch pipe and the second branch pipe are respectively detachably connected with and communicated with the corresponding connectors 103 f.

It is understood that a set of connectors 103f is connected to a corresponding branch pipe 103 b.

Wherein, the connector 103f can be welded on the main pipe 103a or integrally formed with the main pipe 103 a; the first branch pipe and the second branch pipe are respectively in threaded connection or flange connection with the corresponding connectors 103 f.

The heat exchange section 2 for preheating the etherification raw material and cooling the primary etherification product from the first reaction section 1 may be configured in various structures, and in the embodiment of the present invention, in order to improve the heat exchange rate between the etherification raw material and the primary etherification product, the heat exchange section 2 includes: a shell side for preheating the etherification feedstock, and a tube side for cooling the first-stage etherification product.

Further, on the premise of simple structure, as shown in fig. 2, the heat exchange section 2 includes: the device comprises a middle shell 201, an upper partition plate 202, a lower partition plate 203 and a plurality of heat exchange tubes 204 for conveying a first-stage etherification product; the wall of the middle shell 201 is provided with a shell-side inlet 201a and a shell-side outlet 201b, and the shell-side outlet 201b is communicated with the other port of the main pipe 103a through an outer pipe 205; an upper partition plate 202 and a lower partition plate 203 are respectively arranged at the upper end and the lower end of the middle shell 201; the plurality of heat exchange tubes 204 are vertically arranged between the upper baffle 202 and the lower baffle 203, and the upper and lower ports are respectively communicated with the first reaction section 1 and the second reaction section 3.

Through the arrangement, the etherification raw material enters the middle shell 201 through the shell side inlet 201a, and exchanges heat with the first-stage etherification product which falls into the heat exchange tube 204 from the first reaction section 1 by means of the self gravity; then, the preheated etherification raw material flows into the feed distributor 103 through a shell side outlet 201b and an outer pipe 205 for distribution, and then falls into the first catalyst bed layer 102; meanwhile, the cooled first-stage etherification product falls into the second reaction section 3 by means of self gravity.

It should be noted that the inner space of the heat exchange tube 204 forms the tube pass of the heat exchange section 2; the space between the heat exchange tubes 204 and the middle shell 201 constitutes the shell side of the heat exchange section 2, and the shell side inlet 201a is used for feeding. In addition, the outer pipe 205 is located outside the middle case 201 and the upper case 101.

The middle shell 201 is set to be a cylindrical structure, so that the structure of the middle shell 201 is matched with that of the cylindrical part of the upper shell 101, the middle shell 201 is connected with the upper shell 101 and conducted conveniently, and then the upper end opening of the heat exchange tube 204 is conducted with the first reaction section 1.

In order to further improve the heat convection effect between the etherification raw material and the first-order etherification product, the shell-side inlet 201a and the shell-side outlet 201b are located on two opposite side walls of the middle shell 201, and the shell-side inlet 201a and the shell-side outlet 201b are respectively located at the lower end and the upper end of the middle shell 201 (see fig. 2). Through the arrangement, the flow direction of the etherification raw material in the shell pass is opposite to that of the first-stage etherification product in the previous round in the tube pass, and the heat convection is facilitated.

The structures of the upper partition plate 202 and the lower partition plate 203 are adapted to the structure of the middle shell 201, for example, if the middle shell 201 is a cylindrical structure, the upper partition plate 202 and the lower partition plate 203 are disc-shaped structures, so that the upper partition plate 202 and the lower partition plate 203 can be abutted against the inner wall of the middle shell 201, and on one hand, the etherification raw materials in the shell pass of the heat exchange section 2 are prevented from entering the first reaction section 1 from the gap between the upper partition plate 202 and the middle shell 201, and from entering the second reaction section 3 from the gap between the lower partition plate 203 and the middle shell 201; on the other hand, the first-stage etherification products in the first reaction section 1 are prevented from entering the shell side of the heat exchange section 2 from the gap between the upper baffle plate 202 and the middle shell 201.

It can be understood that a plurality of vertical through holes are formed in each of the upper partition plate 202 and the lower partition plate 203, and the vertical through holes in the upper partition plate 202 correspond to the vertical through holes in the lower partition plate 203 one by one, so that the heat exchange tubes 204 are vertically fixed in the vertical through holes in the upper partition plate 202 and the lower partition plate 203.

Regarding the arrangement of the vertical through holes, as exemplified above by the partition plate 202, the vertical through holes on the upper partition plate 202 may be divided into a plurality of groups, each group of vertical through holes is uniformly distributed along the circumferential direction of the upper partition plate 202, and two adjacent groups of vertical through holes are staggered with each other (see fig. 4). Through the arrangement, the heat exchange efficiency of the etherification raw material and the first-stage etherification product in the previous round can be improved.

It should be noted that, for convenience of describing the arrangement of the vertical through holes, only a part of the vertical through holes are shown on the upper partition plate 202 in fig. 4.

The distance between the two adjacent vertical through holes can be set to 80 mm-300 mm, for example, the distance can be set to 80mm, 160mm, 240mm, 300mm and the like, so that the upper partition plate 202 can have certain strength, and the first-stage etherification product can flow into the heat exchange tube 204.

In addition, there are various ways for the upper partition plate 202 and the lower partition plate 203 to be disposed on the middle casing 201, as long as the upper partition plate 202 and the lower partition plate 203 can be fixed on the inner wall of the middle casing 201, and the upper partition plate 202 and the lower partition plate 203 can be respectively abutted against the inner wall of the middle casing 201, and two embodiments are given below:

as a first embodiment, as shown in fig. 5a, the inner walls of the upper and lower ends of the middle casing 201 are respectively provided with an upper stopper 208a and a lower stopper 208 b; the upper baffle 202 is arranged on the upper limit piece 208a, and a first sealing ring 209a is arranged between the upper baffle 202 and the middle shell 201; the lower diaphragm 203 is disposed on the lower stopper 208b, and a second seal ring 209b is disposed between the lower diaphragm 203 and the middle housing 201.

The upper limiting member 208a and the lower limiting member 208b may be provided with various structures, as long as they can be respectively fixed on the upper partition plate 202 and the lower partition plate 203, for example, the upper limiting member 208a and the lower limiting member 208b may be ring-shaped structures, or may be composed of a plurality of limiting blocks uniformly arranged along the circumferential direction of the middle housing 201.

The upper and lower limiting

members

208a and 208b may be welded to the inner wall of the middle housing 201, which is convenient for production and processing.

Regarding the connection between the upper partition plate 202 and the upper stopper 208a, and the connection between the lower partition plate 203 and the lower stopper 208b, a bolt connection method may be adopted, which facilitates the replacement of the upper partition plate 202 and the lower partition plate 203.

In addition, regarding the manner of mounting the first and second sealing rings 209a and 209b, annular grooves may be formed on the inner walls of the upper and lower ends of the middle case 201 to accommodate the first and second sealing rings 209a and 209b, respectively; or annular grooves are respectively arranged on the outer walls of the upper partition plate 202 and the lower partition plate 203 so as to correspondingly accommodate the first sealing ring 209a and the second sealing ring 209 b.

The first seal ring 209a and the second seal ring 209b may be fixed by bolts.

As a second embodiment, as shown in fig. 5b, a first annular clamping groove and a second annular clamping groove are respectively formed on the inner walls of the upper end and the lower end of the middle housing 201, a first elastic retaining ring 2010a is accommodated in the first annular clamping groove, and a second elastic retaining ring 2010b is accommodated in the second annular clamping groove; the upper partition plate 202 is arranged on the first elastic retainer ring 2010a, and a third sealing ring 2011a is arranged between the upper partition plate 202 and the middle shell 201; the lower partition plate 203 is provided on the second circlip 2010b, and a fourth seal 2011b is provided between the lower partition plate 203 and the middle housing 201. By providing as above, it is convenient to detach and mount the first and second circlips 2010a, 2010 b.

The installation and removal processes of the first and second circlips 2010a and 2010b are the same, and the installation and removal processes are described below with reference to the first circlip 2010a as an example:

when the first elastic check ring 2010a is installed, the first elastic check ring 2010a is clamped firstly and is placed into the middle shell 201; when the first elastic check ring 2010a reaches the first annular clamping groove, the first elastic check ring 2010a is loosened to reset, and then the first elastic check ring is clamped into the first annular clamping groove. When the first elastic check ring 2010a is detached, the first elastic check ring 2010a is clamped firstly, so that the first elastic check ring 2010a enters the middle shell 201 from the first annular clamping groove; thereafter, the first circlip 2010a is continuously clamped until it is pulled out to the outside of the etherification apparatus.

The first and second circlips 2010a and 2010b are retractable circlips with openings, and tool holes may be provided in the circlips for clamping the first and second circlips 2010a and 2010 b.

The first elastic check ring 2010a and the upper partition plate 202 can be connected in a bolt connection mode, and the second elastic check ring 2010b and the lower partition plate 203 are connected, so that the upper partition plate 202 and the lower partition plate 203 can be conveniently disassembled.

The mounting positions of the third and

fourth seals

2011a, 2011b may be the same as the mounting positions of the first and

second seals

209a, 209b in the first embodiment.

The third seal ring 2011a and the fourth seal ring 2011b may be fixed by bolts.

The heat exchange tube 204 may be configured into various structures as long as the heat exchange between the etherification raw material and the first-stage etherification product in the previous round is not affected, and for example, the heat exchange tube may be configured into a light tube, a threaded tube, or the like.

In order to improve the heat exchange rate, in the embodiment of the present invention, the heat exchange tube 204 is preferably a threaded tube, which can increase the heat exchange area and improve the heat transfer coefficient at the same time, thereby achieving the purpose of secondary heat transfer enhancement.

Specifically, the heat exchange pipe 204 includes: the parent tube, set up the screw thread form fin on the parent tube outer wall. The fins may be installed on the base pipe by rolling to improve the strength of the heat exchange tube 204.

The length of the heat exchange tube 204 may be 1.5m to 3m (e.g., 1.5m, 2m, 2.5m, 3m, etc.), the outer diameter of the substrate tube is 19mm to 38mm (e.g., 19mm, 25mm, 38mm, etc.), the wall thickness is not less than 2.5mm (e.g., 2.5mm, 3mm, 3.5mm, etc.), the fin height is 1.0mm to 1.4mm (e.g., 1.0mm, 1.1mm, 1.2mm, 1.3mm, 1.4mm, etc.), and the fin pitch is 0.8mm to 2.5mm (e.g., 0.8mm, 1.0mm, 1.2mm, 2.0mm, 2.5mm, etc.), and the embodiments of the present invention do not specifically limit the above parameters of the heat exchange tube 204 as long as effective heat exchange can be performed.

The heat exchange tube 204 can be made of various materials as long as the heat exchange tube can effectively exchange heat, for example, in the embodiment of the invention, the heat exchange tube 204 is made of S31603 stainless steel, which not only has a good heat transfer coefficient, but also is corrosion-resistant, and the service life of the heat exchange tube 204 can be prolonged.

In addition, the connection mode of the upper and lower ports of the heat exchange tube 204 with the upper and

lower partition plates

202 and 203 can be set to be various, for example, the connection mode can be a screw connection mode, which is convenient for replacing the heat exchange tube 204.

In order to prevent the catalyst particles in the first catalyst bed 102 from entering the heat exchange tubes 204, as shown in fig. 2, in the embodiment of the present invention, the heat exchange section 2 further includes: a plurality of first screens 206; the first screen 206 is disposed on the upper barrier 202 and is in communication with the upper port of the corresponding heat exchange tube 204.

It should be noted that the heat exchange tubes 204 are in one-to-one correspondence with the first screens 206, that is, an upper port of each heat exchange tube 204 is communicated with the corresponding first screen 206.

The first screen 206 may be provided in various structures as long as the catalyst particles in the first catalyst bed 102 are prevented from entering the heat exchange tubes 204, for example, a plate structure or a cylindrical structure with a closed upper end.

With either configuration, the first screen 206 has a mesh opening size smaller than the catalyst particle size of the first catalyst bed 102. At present, the particle size of the catalyst used may be as small as 0.25mm, and the mesh opening size of the first screen 206 may be set to 0.15mm to 0.16mm (e.g., 0.15mm, 0.16mm, etc.).

Furthermore, since the pressure drop in the etherification unit is as large as 0.1MPa, the maximum pressure drop that can be tolerated by the first screen 206 is 0.1 MPa. If the first catalyst bed 102 is directly stacked on the upper partition 202, the first screen 206 on the upper partition 202 is required to bear the weight of the entire first catalyst bed 102, and the first screen 206 may be made of high strength steel, such as S30403 and S31603 stainless steel, and at the same time, the first screen 206 is prevented from being corroded, thereby prolonging the service life of the first screen 206.

Specifically, as shown in fig. 6, the first screen 206 of the cylindrical structure may include: a frame 206a for being disposed on the upper baffle 202, a plurality of annularly configured rider bars 206b, a cover plate 206 c; the frame 206a includes a plurality of support rods distributed circumferentially; a plurality of screen bars 206b are arranged on the side wall of the frame 206a in a winding manner and are arranged at intervals along the axial direction of the frame 206 a; the cover plate 206c is provided with a plurality of screen holes and is coupled to the top of the frame 206 a.

Through the arrangement, the first screen 206 can effectively prevent the catalyst particles in the first catalyst bed layer 102 from entering the heat exchange tube 204, reduce the risk of blocking the first screen 206 by the catalyst particles, and simultaneously uniformly distribute the first-stage etherification product flowing into the heat exchange tube 204, so that the first-stage etherification product can conveniently flow into the heat exchange tube 204.

It should be noted that the strip-shaped gaps between two adjacent screen bars 206b form the screen holes of the first screen 206, and the minimum dimension (i.e., the screen hole diameter) of the strip-shaped gaps is smaller than the catalyst particle size of the first catalyst bed 102.

Wherein, the height of the frame 206a can be 50 mm-80 mm (for example, 50mm, 60mm, 70mm, 80mm, etc.), the inner diameter is larger than the outer diameter of the heat exchange pipe 204, and can be set to be 25 mm-50 mm (for example, 25mm, 30mm, 35mm, 40mm, 45mm, 50mm, etc.); the width of the screen bars 206b is 2.0mm to 3.0mm (e.g., 2.0mm, 2.5mm, 3mm, etc.), and the embodiment of the present invention does not specifically limit the above parameters, and not only can effectively prevent the catalyst particles in the first catalyst bed 102 from entering the heat exchange tube 204, but also can support the first catalyst bed 102.

In addition, the screen bars 206b can be welded on the inner side wall or the outer side wall of the support rod, and the cover plate 206c can also be welded on the top wall of the support rod, so that the production and the processing are convenient.

To facilitate the installation of the first screen 206 and the heat exchange tubes 204 on the upper partition 202, as shown in fig. 6, the heat exchange section 2 further comprises: a plurality of first connectors 2012 provided with vertical channels; the upper end of the first connector 2012 is communicated with the corresponding first screen 206, and the lower end thereof passes through and is fixed in the upper partition 202, and is detachably connected with and conducted to the upper port of the corresponding heat exchange tube 204.

The first connecting member 2012 can be configured in various structures, for example, as shown in fig. 6, in an embodiment of the invention, the first connecting member 2012 includes: a support plate 2012a, a screw 2012b vertically connected to the support plate 2012 a; the support plate 2012a is provided with an upper vertical passage and is communicated with the first screen 206; the screw 2012b is provided with a lower vertical channel and is threaded with the upper port of the heat exchange tube 204 through the upper partition 202. By the above arrangement, the processing of the first connector 2012 is facilitated.

It should be noted that the upper vertical passage and the lower vertical passage constitute a vertical passage on the first connecting member 2012.

Wherein the first screen 206 may be welded to the support plate 2012 a; the supporting plate 2012a and the screw 2012b are connected by welding or integrally formed.

Based on the first connecting piece 2012 with the above structure, in order to prevent the first-stage etherification product from flowing into the shell side of the heat exchange section 2 from the gap between the screw 2012b and the upper partition plate 202, as shown in fig. 6, the upper end and the lower end of the screw 2012b are both fixed on the upper partition plate 202 through a nut 2012c, and a gasket 2012d is disposed between the nut 2012c and the upper partition plate 202.

Likewise, the second screen 207 may have the same structure as the first screen 206 described above, and the second screen 207 and the lower ports of the heat exchange tubes 204 may be mounted on the lower partition 203 in the same manner as the first screen 206 and the upper ports of the heat exchange tubes 204 are mounted on the upper partition 202.

The second reaction section 3 for forming the primary etherification product into the secondary etherification product and discharging it may be provided in various configurations, for example, as shown in fig. 2, in the embodiment of the present invention, the second reaction section 3 includes: a lower shell 301 and a second catalyst bed 302; the second catalyst bed 302 is arranged in the lower shell 301; the bottom of the lower shell 301 is provided with a discharge port 3a, and the top is communicated with the middle shell 201.

The second reaction section 3 is simple in structure and convenient to produce and process.

Wherein, the structure of lower casing 301 can set to the multiple, for example, lower casing 301 can be formed by spherical head and barrel welding, also makes the top structure of lower casing 301 and the structure looks adaptation of well casing 201 be convenient for the top of lower casing 301 and well casing 201 to be connected and switch on.

During production, the cylinder part of the upper shell 101, the middle shell 201 and the cylinder part of the lower shell 301 can be integrally and sequentially molded, so that the processing is convenient, and the strength of the device can be improved.

Based on the lower housing 301 with the above structure, in order to facilitate the disassembly and assembly of the discharge port 3a, the discharge port 3a can be flange-connected with the sealing head of the lower housing 301 (see fig. 7).

In addition, the catalyst in the second catalyst bed 302 can also be selected as cation exchange resin, and the bed height and the catalyst particle size are the same as those of the first catalyst bed 102.

Regarding the installation of the second catalyst bed 302, it may be either disposed on the inner wall of the lower shell 301 through a grid plate or a plurality of catalyst particles may be stacked directly on the lower end of the lower shell 301 to form the bed (see fig. 2).

The latter embodiment is preferred, and the installation of the second catalyst bed 302 is such that the use of a grid is avoided, reducing processing costs.

Further, in order to prevent the catalyst particles in the second catalyst bed 302 from being discharged through the discharge port 3a, as shown in fig. 2 and fig. 7, a third screen 303 is further disposed at the discharge port 3a to prevent the catalyst in the second catalyst bed 302 from being discharged through the discharge port 3a along with the secondary etherification product.

Wherein the structure of the third screen 303 can be configured into a cylindrical structure with a closed top (see fig. 7) to increase the treatment area of the catalyst particles in the secondary etherification product. It should be noted that the mesh opening of the third screen 303 is smaller than the catalyst particle size of the second catalyst bed 302.

Specifically, the third screen 303 may include: a cylindrical body 303a, and a top plate 303b connected to the cylindrical body 303 a; the cylinder 303a is provided with a plurality of vertical strip-shaped holes, and the plurality of strip-shaped holes are uniformly distributed along the circumferential direction of the cylinder 303 a; the cylinder 303a is provided at the discharge port 3a (see fig. 7). By providing as above, the risk of catalyst particles clogging the third screen 303 may be reduced.

The cylinder 303a and the top plate 303b are connected by welding or integrally molded.

The width and length of the strip-shaped holes are not particularly limited in the embodiment of the present invention, as long as the catalyst particles in the secondary etherification product can be effectively filtered and the secondary etherification product can be discharged in time, for example, in the embodiment of the present invention, the sum of the areas of the plurality of strip-shaped holes is at least twice the cross-sectional area of the discharge port 3 a.

In addition, the maximum pressure drop that can be tolerated by the third screen 303 and the steel type used are the same as for the first screen 206.

In order to facilitate the placing and taking out of the third screen 303 into the lower shell 301, as shown in fig. 7, the second reaction section 3 further includes: a second connecting member 305 provided with a vertical passage; the upper end of the second connecting member 305 communicates with the cylinder 303a of the third screen 303, and the lower end communicates with the discharge port 3 a.

The second connecting member 305 may be configured in various structures, for example, as shown in fig. 7, in an embodiment of the present invention, the second connecting member 305 includes: a pad 305a, a tube body 305b vertically connected to the pad 305 a; the backing plate 305a is provided with a channel and is communicated with a cylinder 303a of the third screen 303; the lower end of the pipe body 305b communicates with the discharge port 3 a.

It should be noted that the vertical channel of the backing plate 305a and the inner cavity of the tube body 305b form a vertical channel of the second connector 305.

The outer diameter of the backing plate 305a is greater than or equal to the outer diameter of the third screen 303, and the backing plate 305a is not abutted against the inner wall of the lower shell 301, so that the third screen 303 and the second connecting piece 305 are favorably placed into the lower shell 301 while the discharge port 3a is installed.

Wherein the cylinder 303a of the third screen 303 may be welded to the pad 305 a; the pad 305a and the tube 305b are connected by welding or integrally formed.

In order to avoid damaging the third screen 303 due to the over-high temperature of the second catalyst bed 302, as shown in fig. 2, a plurality of inert ceramic balls 304 are filled between the second catalyst bed 302 and the third screen 303.

It is understood that a plurality of inert ceramic balls 304 are filled in the space formed between the second catalyst bed 302, the lower shell 301 and the third screen 303. And the inert ceramic balls 304 do not react with the secondary etherification product, and have certain strength to support the second catalyst bed 302.

The particle size of the inert ceramic balls 304 is 2mm to 4mm (e.g., 2mm, 3mm, 4mm, etc.), and the upper surfaces of the plurality of inert ceramic balls 304 are 90mm to 110mm (e.g., 90mm, 100mm, 110mm, etc.) above the top plate 303b of the third screen 303.

Similarly, a plurality of inert ceramic balls may be disposed between the first catalyst bed 102 and the upper screen 202 to protect the upper screen 202 and the first screen 206.

In the second reaction section 3 having the above-described structure, in order to improve the conversion rate of the etherification raw material and the processing speed, in the embodiment of the present invention, the distance between the top of the third screen 303 and the top of the second catalyst bed 302 is 300mm to 600mm, and for example, the distance may be set to 300mm, 400mm, 500mm, 600mm, or the like.

In the embodiment of the present invention, at least one manhole may be disposed on the upper shell 101, the middle shell 201, and the lower shell 301, so as to facilitate the assembly and disassembly of the device.

In addition, the device provided by the embodiment of the invention can also be used for other devices in which the catalyst is resin, the reaction is exothermic, and the two reactors are operated in series, such as an MTBE (Methyl Tert-butyl Ether) device, an ETBE (Ethyl Tert-butyl Ether) device, a gasoline blending device and the like.

The following compares the apparatus provided in the examples of the present invention with the apparatus for etherification of catalytic light gasoline of the prior art in terms of specification, energy consumption, floor space and investment cost under the same parameters of etherification raw materials and engineering conditions, and the results are shown in table 1.

TABLE 1

The specification of the heater is: a U-shaped tubular heat exchanger with a nominal diameter of 500 mm; the design pressure of a tube side and a shell side is 2.5Mpa, and the nominal heat exchange area is 50 square meters; the heat exchange tube is 6m in length, 25mm in outer diameter, 4 tube passes and an I-level tube bundle. The specification of the cooler is as follows: a U-shaped tubular heat exchanger with a nominal diameter of 400 mm; the design pressure of the tube side shell side is 2.5Mpa, the nominal heat exchange area is 25 square meters, the length of the heat exchange tube is 6m, the outer diameter is 25mm, 4 tube sides and I-grade tube bundles. In addition, the occupied area of the catalytic light gasoline etherification device in the prior art is 4.7 times of that of the device in the embodiment of the invention, and the investment cost is 2.6 times of that of the device in the embodiment of the invention.

Therefore, the device provided by the embodiment of the invention does not consume steam and circulating water, while the catalytic light gasoline etherification device in the prior art needs to consume 796kg/h of 1.0MPa steam and 37300kg/h of circulating water; for the number of required equipment, the device provided by the embodiment of the invention only needs one phi 2000X 20600mm etherification reactor, while the catalytic light gasoline etherification device in the prior art needs two phi 2000X 11800mm etherification reactors and two cold exchange devices; in addition, the device provided by the embodiment of the invention is far smaller than the catalytic light gasoline etherification device in the prior art in terms of occupied area and investment.

In a second aspect, an embodiment of the present invention further provides a catalytic light gasoline etherification method, which is implemented by using the above apparatus, and includes:

and (3) conveying the etherification raw material into the heat exchange section 2, and carrying out heat exchange on the etherification raw material and the primary etherification product from the first reaction section 1 to preheat the etherification raw material and cool the primary etherification product.

And (3) utilizing the first reaction section 1 to generate a first-stage etherification product from the preheated etherification raw material.

And (3) utilizing the second reaction section 3 to generate a secondary etherification product from the cooled primary etherification product, and discharging the secondary etherification product.

According to the method, the etherification treatment of the catalytic light gasoline can be realized through the cooperation of the first reaction section 1, the heat exchange section 2 and the second reaction section 3, so that additional equipment such as a heater, a cooler and the like is avoided, the equipment cost and the operation cost are saved, the energy consumption is reduced, and the occupied area is reduced.

Wherein the temperature of the etherification raw material is 30-40 ℃, the pressure is 0.60-1.40 Mpa, the temperature can be increased to 45-60 ℃ after the heat exchange with the first-stage etherification product in the previous round, and the pressure can be reduced to 0.59-1.39 MPa.

In addition, the temperature of the primary etherification product generated by the preheated etherification raw material is 65-90 ℃ and the pressure is 0.49-1.34 MPa, the temperature is reduced to 50-70 ℃ and the pressure is reduced to 0.46-1.31 MPa after the heat exchange with the previous round of etherification raw material, the temperature of the generated secondary etherification product is 55-75 ℃ and the pressure is 0.40-1.25 MPa.

In the apparatus provided in the embodiment of the present invention, when the first reaction section 1 is equipped with the feed distributor 103 having the above-mentioned structure, in order to facilitate the flow of the etherification raw material into the first catalyst bed 102 and to increase the content of the first-order etherification product formed from the etherification raw material, the hole velocity of the feed distributor 103 is set to 0.10m/s to 0.15m/s, for example, 0.10m/s, 0.11m/s, 0.12m/s, 0.13m/s, 0.14m/s, 0.15m/s, etc.

It should be noted that the orifice velocity of feed distributor 103 refers to the flow rate of etherification feedstock through the fluid flow holes of feed distributor 103.

Further, in the apparatus provided in the embodiment of the present invention, when the heat exchange section 2 adopts the above structure, in order to improve the heat exchange efficiency between the first-stage etherification product and the next round of etherification raw material in the heat exchange section 2, in the method, the flow velocity of the first-stage etherification product in the heat exchange tube 204 is set to 0.7m/s to 1.5m/s, for example, the flow velocity may be set to 0.7m/s, 0.9m/s, 1.1m/s, 1.3m/s, 1.5m/s, and the like.

In addition, the amount of the catalyst stacked in the first reaction section 1 and the second reaction section 3 can be 0.8h according to the liquid hourly space velocity^-1～1.2h^-1(e.g., 0.8 h)^-1、1.0h^-1、1.2h^-1Etc.) can improve the conversion rate of the etherification raw materials and avoid the waste of the catalyst. Wherein, the liquid hourly space velocity refers to the ratio of the volume of the catalyst to the flow rate of the etherification raw material.

All the above optional technical solutions may be combined arbitrarily to form the optional embodiments of the present disclosure, and are not described herein again.

The above description is only exemplary of the present invention and should not be taken as limiting the scope of the present invention, as any modifications, equivalents, improvements and the like made within the spirit and principle of the present invention should be included in the scope of the present invention.

Claims

1. A catalytic light gasoline etherification unit, characterized in that it comprises: the device comprises a first reaction section (1), a heat exchange section (2) and a second reaction section (3) which are arranged from top to bottom in sequence;

the heat exchange section (2) is used for preheating etherification raw materials and cooling primary etherification products from the first reaction section (1);

the first reaction section (1) is used for reacting the preheated etherification raw materials to generate a first-order etherification product;

the second reaction section (3) is used for reacting the cooled first-stage etherification product to generate a second-stage etherification product.

2. The apparatus according to claim 1, wherein the first reaction section (1) comprises: an upper shell (101) with a closed top and a first catalyst bed layer (102);

the first catalyst bed (102) is disposed within the upper housing (101).

3. The apparatus according to claim 2, wherein the first reaction section (1) further comprises: a feeding distributor (103) which is communicated with the heat exchange section (2) and is used for distributing the preheated etherification raw materials;

the feed distributor (103) is disposed within the upper shell (101) and above the first catalyst bed (102).

4. The apparatus according to claim 3, wherein the feed distributor (103) comprises: a main pipe (103a), a plurality of branch pipes (103 b);

the branch pipes (103b) are communicated with the main pipe (103a) and are arranged at intervals along the axial direction of the main pipe (103 a);

a plurality of fluid through holes are formed in the branch pipe (103b), and two ports are closed;

one port of the main pipe (103a) is closed, and the other port is communicated with the heat exchange section (2).

5. An arrangement according to claim 4, characterized in that the heat exchange section (2) comprises: a middle shell (201), an upper partition plate (202), a lower partition plate (203), and a plurality of heat exchange tubes (204) for conveying the primary etherification product;

a shell side inlet (201a) and a shell side outlet (201b) are arranged on the wall of the middle shell (201), and the shell side outlet (201b) is communicated with the other port of the main pipe (103a) through an outer pipe (205);

the upper partition plate (202) and the lower partition plate (203) are respectively arranged at the upper end and the lower end of the middle shell (201);

the plurality of heat exchange tubes (204) are vertically arranged between the upper partition plate (202) and the lower partition plate (203), and the upper end port and the lower end port of each heat exchange tube are respectively communicated with the first reaction section (1) and the second reaction section (3).

6. An arrangement according to claim 5, characterized in that the heat exchange section (2) further comprises: a plurality of first screens (206), a plurality of second screens (207);

the first screen (206) is arranged on the upper partition plate (202) and is communicated with the upper end opening of the corresponding heat exchange pipe (204);

the second screen (207) is arranged on the lower partition plate (203) and is communicated with the lower port of the corresponding heat exchange tube (204).

7. The apparatus according to claim 5, characterized in that the second reaction section (3) comprises: a lower shell (301) and a second catalyst bed (302);

the second catalyst bed (302) is arranged in the lower shell (301);

the bottom of the lower shell (301) is provided with a discharge hole (3a), and the top of the lower shell is communicated with the middle shell (201).

8. The device according to claim 7, characterized in that a third screen (303) is arranged at the discharge opening (3 a).

9. The apparatus according to claim 8, wherein a plurality of inert ceramic balls (304) are filled between the second catalyst bed (302) and the third screen (303).

10. A catalytic light gasoline etherification process using the catalytic light gasoline etherification apparatus according to any one of claims 1 to 9, wherein the process comprises:

conveying an etherification raw material into a heat exchange section (2), and carrying out heat exchange on the etherification raw material and a primary etherification product from a first reaction section (1) to preheat the etherification raw material and cool the primary etherification product;

utilizing the first reaction section (1) to generate a first-stage etherification product from the preheated etherification raw material;

and (4) utilizing the second reaction section (3) to generate a secondary etherification product from the cooled primary etherification product, and discharging the secondary etherification product.