CN112536002B

CN112536002B - Central tube for radial moving bed reactor

Info

Publication number: CN112536002B
Application number: CN201910897076.1A
Authority: CN
Inventors: 胡庆均; 陈绍庆; 徐又春; 赵建新; 赵璐; 冯勇; 郭劲鹤; 寇肖
Original assignee: China Petroleum and Chemical Corp; Sinopec Luoyang Petrochemical Engineering Corp; Sinopec Engineering Group Co Ltd
Current assignee: China Petroleum and Chemical Corp; Sinopec Engineering Group Co Ltd; Sinopec Luoyang Guangzhou Engineering Co Ltd
Priority date: 2019-09-23
Filing date: 2019-09-23
Publication date: 2022-10-14
Anticipated expiration: 2039-09-23
Also published as: CN112536002A

Abstract

The invention discloses a central tube for a radial moving bed reactor, which aims to solve the problem that an open-pore inner tube and a screen of the existing central tube are cracked. The central tube is provided with an inner perforated tube, a screen, a bottom plate, a blind tube and a blind plate. An inner boss and an outer boss are arranged on the bottom plate from inside to outside around the center hole of the bottom plate. The top of the perforated inner cylinder is welded with the blind plate, and the bottom of the perforated inner cylinder is welded with the top of the inner boss. The top of the blind cylinder is welded with the blind plate, the top of the screen bar in the screen is welded with the bottom of the blind cylinder, and the bottom of the screen bar is welded with the top of the outer boss. The invention provides the high length of the bottom edge of an isosceles triangle on the cross section of the screen bar, and the thickness of an outer boss, an opening inner cylinder, an inner boss, a blind cylinder and a blind plate. The bottom plate, the inner boss and the outer boss are integrally machined parts. The invention is mainly used in the radial moving bed reactor in the petrochemical industry.

Description

Central tube for radial moving bed reactor

Technical Field

The invention relates to a central tube for a radial moving bed reactor.

Background

In the petrochemical industry, moving bed reaction processes (e.g., continuous reforming) are important means to ensure continuous production of high quality oil and chemical products, and the core equipment used is a radial moving bed reactor. The core components of a radial moving bed reactor (referred to simply as a reactor) are a central tube and a fan-shaped cylinder (or outer net). The catalyst passes through an annular space formed by the central tube and the fan-shaped cylinder (or the outer net) from top to bottom in the reactor, a reaction medium radially passes through the catalyst bed layer from the fan-shaped cylinder (or the outer net) for reaction, and a reaction product generated after the reaction enters the inner cavity of the central tube. In a radial moving bed reactor of the prior art, the reaction medium inlet is located in the side wall of the reactor shell. The central tube comprises an inner tube with holes, a screen, a bottom plate, a blind tube, a blind plate, a connecting ring and the like. The perforated inner cylinder and the screen are arranged from inside to outside. The screen cloth comprises grating and screen cloth backup ring, and screen cloth backup ring is located between grating and the trompil inner tube, and the cross sectional shape of grating is isosceles triangle. The bottom of the perforated inner cylinder and the bottom of the screen bars are welded on the bottom plate, and the top of the perforated inner cylinder and the top of the screen bars are welded on the connecting ring. The bottom of the blind cylinder is welded on the connecting ring, and the top of the blind cylinder is welded with the blind plate. The bottom plate is provided with a bottom plate center hole. The thickness of the perforated inner cylinder is relatively thin and the height of the isosceles triangle on the bottom edge of the cross section of the screen bars is relatively small, while the thickness of the bottom plate and the connecting ring is relatively thick (generally more than 50 mm). When the reactor is operated at high temperature and temperature fluctuation is severe, the deformation of the perforated inner cylinder and the deformation of the screen mesh, the deformation of the bottom plate and the deformation of the connecting ring are inconsistent, large temperature difference stress is generated, and the perforated inner cylinder and the screen mesh are cracked due to the welding connection of the connecting parts of the perforated inner cylinder and the connecting ring due to large sudden change of the structure size of the connecting parts of the perforated inner cylinder and the screen bars, the bottom plate and the connecting ring.

Disclosure of Invention

The invention aims to provide a central tube for a radial moving bed reactor, which solves the problem that an open-pore inner tube and a screen of the existing central tube are cracked.

In order to solve the problems, the technical scheme adopted by the invention is as follows: a central tube for a radial moving bed reactor is provided with an opening inner tube, a screen, a bottom plate, a blind tube and a blind plate, wherein the opening inner tube and the screen are arranged from inside to outside. The screen cloth comprises grating and screen cloth backup ring, and screen cloth backup ring is located between grating and the trompil inner tube, and the cross sectional shape of grating is isosceles triangle. The inner perforated cylinder is provided with a perforated hole, the bottom plate is provided with a central hole of the bottom plate, and the top of the blind cylinder is connected with the blind plate in a welding way. An inner boss and an outer boss are arranged on the bottom plate from inside to outside around the center hole of the bottom plate. The top of the inner perforated cylinder is welded with the blind plate, and the bottom of the inner perforated cylinder is welded with the top of the inner boss. The top of the screen bar is welded with the bottom of the blind cylinder, and the bottom of the screen bar is welded with the top of the outer boss. The height b of the bottom edge of an isosceles triangle on the cross section of the screen bar is generally 1-15 mm, and the thickness a of the outer boss is generally b-b +1 mm. The thickness d of the perforated inner cylinder is generally 2-20 mm, and the thickness c of the inner boss is generally d-d +1 mm. The thickness g of the blind cylinder and the thickness f of the blind plate are both 2-10 mm. The bottom plate, the inner boss and the outer boss are integrally machined parts.

The height h of the inner and outer bosses is generally 80-400 mm.

The part of the perforated inner cylinder opposite to the blind cylinder can be provided with or without a perforation.

When the radial moving bed reactor is not in operation, a gap of less than 10 mm is preferably left between the inner circle edges of the screen support ring and the blind cylinder support ring and the outer wall of the perforated inner cylinder.

In a preferred embodiment of the present invention, the openings of the opening inner cylinder are arranged in a row along the axial direction of the opening inner cylinder. The side wall of the shell of the radial moving bed reactor is provided with a reaction medium inlet, and in two adjacent rows of open holes, the diameter of the row of open holes far away from the reaction medium inlet is larger than that of the row of open holes near the reaction medium inlet.

The optimal scheme of the invention is that in two adjacent rows of openings, the diameter of the opening farther away from the reaction medium inlet is 1.01-1.2 times of the diameter of the opening closer to the reaction medium inlet. The diameter of the row of openings closest to the inlet for the reaction medium is between 4 and 20 mm.

The invention has the following beneficial effects: (1) The invention improves the structure of the existing central tube, and limits the length of the height on the bottom edge of the isosceles triangle on the cross section of the screen bar and the thickness of the outer boss, the inner boss, the perforated inner tube, the blind tube and the blind plate. Therefore, when the reactor is operated at high temperature and the temperature fluctuation is severe, at the welding joints of the top of the perforated inner cylinder and the blind plate, the bottom of the perforated inner cylinder and the top of the inner boss, the top of the screen bar and the bottom of the blind cylinder, the bottom of the screen bar and the top of the outer boss and the like, the deformation of the perforated inner cylinder and the screen mesh and other parts connected with the perforated inner cylinder and the screen mesh is not easy to be caused to be inconsistent and great temperature difference stress cannot be generated due to the fact that no sudden change with large structural size exists. The welded connection does not cause cracking of the perforated inner cylinder and the screen cloth even though the welding is carried out. In addition, the bottom plate, the inner boss and the outer boss are machined integrally, welding connection is not adopted, the strength is good, and cracking is not easy to occur. (2) The trompil inner tube sets up between the top of blind flange and interior boss, can play fine supporting role for the center tube has fine intensity and rigidity, can not lead to the screen cloth distortion because of the structure size is too big.

The invention is mainly used in the radial moving bed reactor in the petrochemical industry.

The present invention will be described in further detail with reference to the accompanying drawings and specific embodiments. The drawings and detailed description do not limit the scope of the invention as claimed.

Drawings

FIG. 1 is a cross-sectional view of a center tube for a radial moving bed reactor of the present invention taken along an axial direction.

Fig. 2 is a sectional view taken along line a-a in fig. 1. A portion of the inner and outer bosses are shown in partial cross-section in fig. 2.

Fig. 3 is an enlarged view of a portion I in fig. 1.

In fig. 1, 2 and 3, like reference numerals denote like features. The reference numerals denote: the screen comprises a base plate 1, a screen bar 2, an inner perforated cylinder 3, a screen support ring 4, a blind cylinder 5, an opening 6, a blind plate 7, an inner boss 8, an outer boss 9 and a blind cylinder support ring 10.

Detailed Description

Referring to fig. 1, 2 and 3, the central tube (referred to as the central tube for short) for a radial moving bed reactor of the present invention is provided with an open-pore inner tube 3, a screen, a bottom plate 1, a blind tube 5 and a blind plate 7, wherein the open-pore inner tube 3 and the screen are arranged from inside to outside. The screen cloth comprises grating 2 and screen cloth backup ring 4, and screen cloth backup ring 4 is located between grating 2 and the trompil inner tube, and the cross sectional shape of grating 2 is isosceles triangle. The opening inner cylinder 3 is provided with an opening 6, the bottom plate 1 is provided with a bottom plate center hole, and the opening 6 and the bottom plate center hole are circular holes. An inner boss 8 and an outer boss 9 are arranged on the bottom plate 1 from inside to outside around the center hole of the bottom plate. The top of the blind cylinder 5 is welded with the blind plate 7, the top of the perforated inner cylinder 3 is welded with the blind plate 7, and the bottom of the perforated inner cylinder 3 is welded with the top of the inner boss 8. The top of the screen bar 2 is welded with the bottom of the blind cylinder 5, the bottom of the screen bar 2 is welded with the top of the outer boss 9, and a blind cylinder supporting ring 10 is arranged between the blind cylinder 5 and the perforated inner cylinder 3. The cross section shapes of the inner boss 8 and the outer boss 9 and the shapes of the screen supporting ring 4 and the blind cylinder supporting ring 10 are circular rings.

The height b of the isosceles triangle bottom side on the cross section of the screen bar 2 is generally 1-15 mm, and the thickness a of the outer boss 9 is generally b-b +1 mm. In fig. 3, the superimposed section of the screen bars 2, which is painted black, shows the isosceles triangle cross section of the screen bars 2, the height above the base of the isosceles triangle being in the radial direction of the reactor shell. The thickness d of the perforated inner cylinder 3 is generally 2-20 mm, and the thickness c of the inner boss 8 is generally d-d +1 mm. The thickness g of the blind cylinder 5 and the thickness f of the blind plate 7 are both 2-10 mm. g. When f, b and d are selected within their respective ranges, the difference between the selected values of g and f, g and b, d and f should be as small as possible. The height b of the isosceles triangle on the cross section of the screen bar 2, the thickness d of the opening inner cylinder 3, the thickness g of the blind cylinder 5 and the thickness f of the blind plate 7 are approximately the same as those in the prior art.

The base plate 1, the inner boss 8 and the outer boss 9 are integrally machined and are machined from a single metal piece.

The height h of the inner and

outer bosses

8, 9 is typically 80-400 mm (calculated from thermal stress analysis), and the thickness e of the base plate 1 is typically 10-80 mm.

The portion of the perforated inner cylinder 3 opposite the blind cylinder 5 may or may not be provided with the perforations 6, the above-mentioned portion of the perforated inner cylinder 3 shown in fig. 1 being provided with the perforations 6.

The outer circle edges of the screen supporting ring 4 and the blind cylinder supporting ring 10 are respectively fixed on the metal strip 2 and the blind cylinder 5. When the radial moving bed reactor is not in operation, a gap of less than 10 mm (including 0 mm) is preferably left between the inner circular edges of the screen support ring 4 and the blind support ring 10 and the outer wall of the perforated inner cylinder 3, and the gap is calculated according to the thermal expansion amount of each part at high temperature when the reactor is in operation. The existence of the gap ensures that the components can not be damaged due to inconsistent structural deformation even if the reactor is in operation and suffers from sharp temperature fluctuation and the thermal deformation of the screen and the blind cylinder 5 is different from that of the punching inner cylinder 3, so that the temperature fluctuation resistance of the reactor is greatly improved.

The diameter of all the openings 6 in the perforated inner cylinder 3 can be the same. In a preferred embodiment of the present invention, the openings 6 of the opening inner cylinder 3 are arranged in a row along the axial direction of the opening inner cylinder 3 and in a row along the circumferential direction of the opening inner cylinder 3. The openings 6 should avoid the screen support ring 4 and the blind support ring 10. The side wall of the reactor shell is provided with a reaction medium inlet. Of the two adjacent rows of openings 6, the row of openings 6 further from the inlet for the reaction medium has a larger diameter than the row of openings 6 closer to the inlet for the reaction medium. The diameter of each opening 6 in a row of openings 6 is generally the same. In the most preferred embodiment of the present invention, the diameter of the row of openings 6 farther from the reaction medium inlet is 1.01 to 1.2 times the diameter of the row of openings 6 closer to the reaction medium inlet, among the two adjacent rows of openings 6. The diameter of the row of openings 6 closest to the inlet of the reaction medium is generally between 4 and 20 mm.

In fig. 1 and 2, the leftmost opening 6 is closest to the reaction medium inlet and has the smallest diameter. From left to right, the opening 6 has a larger diameter the further it is from the reaction medium inlet. The rightmost opening 6 is furthest from the reaction medium inlet and has the largest diameter.

In the continuous reforming reaction, a reaction medium enters a catalyst bed layer outside a central pipe through a reaction medium inlet on the side wall of the reactor shell, flows along the radial direction and reacts, and a reaction product enters an inner cavity of the open-pore inner cylinder 3 from the open pore 6 and flows out of the reactor from a reaction product outlet. The preferred arrangement of the openings 6 according to the invention makes it possible to increase the uniformity of the distribution of the reaction products in the circumferential direction at each height of the central tube. The reaction medium and the reaction products of the continuous reforming process are all gas phases.

Claims

1. The utility model provides a center tube for radial moving bed reactor, be equipped with trompil inner tube (3), the screen cloth, bottom plate (1), blind section of thick bamboo (5) and blind plate (7), trompil inner tube (3) and screen cloth set up from inside to outside, the screen cloth comprises grating (2) and screen cloth backup ring (4), screen cloth backup ring (4) are located between grating (2) and trompil inner tube (3), the cross sectional shape of grating (2) is isosceles triangle, be equipped with trompil (6) on trompil inner tube (3), be equipped with the bottom plate centre bore on bottom plate (1), the top and blind plate (7) welded connection of blind section of thick bamboo (5), its characterized in that: an inner boss (8) and an outer boss (9) are arranged on a bottom plate (1) from inside to outside around a center hole of the bottom plate, the top of an inner perforated cylinder (3) is in welded connection with a blind plate (7), the bottom of the inner perforated cylinder (3) is in welded connection with the top of the inner boss (8), the top of a screen bar (2) is in welded connection with the bottom of a blind cylinder (5), the bottom of the screen bar (2) is in welded connection with the top of the outer boss (9), the height b of a isosceles triangle bottom edge on the cross section of the screen bar (2) is 1-15 mm, the thickness a of the outer boss (9) is b-b +1 mm, the thickness d of the inner perforated cylinder (3) is 2-20 mm, the thickness c of the inner boss (8) is d-d +1 mm, the thickness g of the blind cylinder (5) and the thickness f of the blind plate (7) are both 2-10 mm, the bottom plate (1), the inner boss (8) and the outer boss (9) are integrally machined parts, a perforated cylinder (3) is provided with a perforated cylinder, a perforated cylinder (6) is arranged along the axial direction of the perforated cylinder (3), a row of the perforated cylinder is larger than the diameter of a reaction medium inlet of a reaction shell which is far away from the inner cylinder, and a row of the reaction medium inlet of the reaction cylinder (6) which is arranged in a column.

2. The base pipe of claim 1, wherein: the height h of the inner boss (8) and the outer boss (9) is 80-400 mm.

3. The base pipe of claim 1, wherein: the part of the perforated inner cylinder (3) opposite to the blind cylinder (5) is provided with or not provided with a perforated hole (6).

4. The base pipe of claim 1, wherein: among two adjacent rows of the openings (6), the diameter of the row of the openings (6) far away from the reaction medium inlet is 1.01 to 1.2 times of the diameter of the row of the openings (6) near the reaction medium inlet.

5. The base pipe according to claim 1 or 4, wherein: the diameter of the row of openings (6) closest to the inlet of the reaction medium is between 4 and 20 mm.