A gas distributor and a fluidized bed reactor applying the gas distributor

Abstract

The present invention discloses a gas distributor, which includes a distribution plate. A plurality of ventilation holes are formed in the distribution plate. It is characterized in that: it further includes a pipe cap arranged below the distribution plate with its cap opening facing upwards. The pipe cap corresponds to the ventilation holes. A plurality of air guiding holes are formed in the side wall of the pipe cap. A baffle is arranged inside the pipe cap around the air guiding holes. A passage for gas to pass through is left between the baffle and the air guiding holes, and the gas discharged from the air guiding holes is downwardly deflected. After the air flow enters the reactor in the present invention, it first flows in along the air guiding holes on the pipe cap. Under the action of the baffle, the air flow direction changes to downward at an angle with the axis of the pipe cap, and then turns back through the concave surface of the pipe cap and enters the upper space of the reactor. Under the action of the gas distributor, the air flow uniformly fills the upper space of the reactor without dead corners, and the air velocities at all parts of the entire cross-section are approximately equal.

Description

Technical Field

[0001] The present invention belongs to the technical field of chemical engineering, and particularly relates to a gas distributor and a fluidized bed reactor applying the gas distributor. Background Art

[0002] A fluidized bed reactor is a reactor in which solid materials (or catalysts) are in a boiling state under the impetus of an air flow. It was early applied in petrochemical industries such as pulverized coal gasification and fluid catalytic cracking. Compared with a fixed bed reactor, the advantages of a fluidized bed reactor are: ① enabling continuous input and output of solid materials; ② having good heat transfer performance and uniform internal temperature, being suitable for highly exothermic reactions; ③ facilitating continuous regeneration and circulation operation of catalysts. However, the fluidized bed reactor also has obvious limitations: ① the distribution of the air flow affects the distribution of solid materials; ② the residence time of reaction materials is relatively long. To achieve uniform air flow distribution, various gas distributor structures have been proposed currently, including porous distribution plates, nozzles, perforated ring pipes, bubble cap distributors, etc.

[0003] For example, a gas distributor for a fluidized bed reactor disclosed in the patent with the publication number CN211706733U mainly includes an upper distribution plate and a lower distribution plate that can rotate around an axis. The upper and lower distribution plates are provided with perforated holes, and the opening ratio of the distributor is changed by the relative rotation of the upper and lower plates. The gas distributor in this scheme is a porous distribution plate, and the gas flows into the reaction zone along the perforated holes on the distribution plate. This design has poor flexibility in adjusting the air flow velocity, resulting in uneven air flow distribution in the reaction zone.

[0004] For example, a gas distributor and a reactor including the gas distributor disclosed in the patent with the publication number CN206715895U include a gas distribution plate and a cap. A plurality of through holes are formed on the gas distribution plate, one end of the cap is open and the other end is closed, and the open end of the cap is connected to the through holes; a plurality of distribution holes for the gas to pass through are formed on the side wall of the cap. The gas distributor in this scheme increases the gas distribution points per unit area and the opening ratio of the distribution holes, but the performance in adjusting the air flow velocity and distribution uniformity is still poor.

[0005] Therefore, the existing gas distributors need to be further improved. Summary of the Invention

[0006] The first technical problem to be solved by the present invention is to provide a gas distributor with uniform air flow distribution.

[0007] The technical solution adopted by the present invention to solve the first technical problem is as follows: A gas distributor includes a distribution plate, and a plurality of ventilation holes are formed in the distribution plate. It is characterized in that: it further includes a pipe cap arranged below the distribution plate with the cap opening facing upward, the pipe cap corresponds to the ventilation holes, a plurality of air guide holes are formed in the side wall of the pipe cap, a baffle is arranged inside the pipe cap around the air guide holes, and a passage for gas to pass through is left between the baffle and the air guide holes, and the gas discharged from the air guide holes is downwardly deflected.

[0008] For more beneficial downward deflection of the gas and achieving uniform distribution of the gas, as a preference, the baffle is arc-shaped and is inclined downward along the upper edge of the air guide hole.

[0009] For more beneficial downward deflection of the gas and achieving uniform distribution of the gas, as a preference, the arc angle α of the baffle is 120° - 150°, the angle β between the baffle and the axis of the pipe cap is 70° - 80°, and the length L of the baffle is 1.5d - 2.5d, where d is the diameter of the air guide hole.

[0010] For more beneficial downward deflection of the gas and achieving uniform distribution of the gas, as a preference, the pipe cap is hemispherical, and the distance D from the center of the air guide hole to the bottom of the pipe cap is 1 / 3 - 1 / 2R, where R is the radius of the pipe cap.

[0011] For more beneficial downward deflection of the gas and achieving uniform distribution of the gas, as a preference, the number of the air guide holes is 3 and they are evenly spaced along the circumferential direction of the pipe cap. The 3 air guide holes are asymmetrically arranged along the center of the pipe cap, avoiding air flow counter - impact and being more beneficial to the uniform distribution of the gas.

[0012] As a preference, clamping rings are arranged at intervals along the circumferential direction of the ventilation holes below the distribution plate, clamping blocks are arranged at intervals along the outer peripheral wall of the pipe cap, and the clamping blocks are located inside the clamping rings. The pipe cap and the distribution plate are detachably connected, which is easy to disassemble and assemble and convenient for replacing the pipe cap later. By replacing the baffle with different inclination angles, the gas flow rate and the size of the inlet hole can be adjusted.

[0013] The second technical problem to be solved by the invention is to provide a fluidized bed reactor applied with the gas distributor.

[0014] The technical solution adopted by the present invention to solve the second technical problem is as follows: A fluidized bed reactor applied with a gas distributor is characterized in that: it includes an upper shell and a lower shell connected to the upper shell, the cavities of the upper shell and the lower shell are communicated, a feed pipe is arranged on the upper shell, the distribution plate is located at the top of the lower shell, and an inlet pipe is arranged on the lower shell below the distribution plate.

[0015] For facilitating the entry of materials, as a preference, the feed pipe is obliquely inserted upward on the upper shell.

[0016] For the uniform dispersion of the introduced gas, preferably, the intake pipe is horizontally penetrated through the lower housing, and a bent pipe is provided at the outlet end of the intake pipe. The outlet of the bent pipe faces downward and is in a horn shape, and the outlet is located at the axis of the lower housing.

[0017] Preferably, the lower housing includes an upper section and a lower section connected to the upper section. The upper section is cylindrical, the distribution plate is located at the top of the upper section, the intake pipe is provided on the upper section, and the lower housing is in a conical shape with a gradually decreasing diameter from top to bottom. The gas flows downward along the axis of the lower housing to the lower section, and under the action of the conical head, the gas flows upward; the upward flowing gas passes through the gas distributor and enters the upper space of the reactor, i.e., the upper housing, to push the catalyst bed layer. The catalyst is suspended inside the reactor, and the gas undergoes a catalytic reaction under the action of the catalyst.

[0018] Compared with the prior art, the advantages of the present invention are as follows: A pipe cap corresponding to the vent holes is provided below the distribution plate in the present invention. A plurality of air guide holes are opened on the side wall of the pipe cap, and a baffle is provided inside the pipe cap around the air guide holes. A passage for the gas to pass through is left between the baffle and the air guide holes, and the gas discharged from the air guide holes is downwardly deflected. After the air flow enters the reactor, it first flows into the reactor along the air guide holes on the pipe cap. Under the action of the baffle, the air flow direction becomes downward at an angle with the axis of the pipe cap, and then turns back through the concave surface of the pipe cap and enters the upper space of the reactor. Under the action of the gas distributor, the air flow is evenly filled into the upper space of the reactor without dead corners, and the gas velocities at all parts of the entire cross-section are approximately equal. On the other hand, the baffle prevents solid materials such as catalysts from blocking the air guide holes, avoiding phenomena such as too large or too small local gas velocities and uneven catalyst distribution. Description of the Drawings

[0019] Figure 1 Schematic structural diagram of the gas distributor in the embodiment of the present invention;

[0020] Figure 2 Partial detail drawing of the gas distributor in the embodiment of the present invention;

[0021] Figure 3 For Figure 2 exploded view;

[0022] Figure 4 For Figure 2 sectional view;

[0023] Figure 5 For Figure 4 schematic view in the A direction in

[0024] Figure 6 For Figure 5 schematic view in the B direction in

[0025] Figure 7 Schematic structural diagram of the pipe cap in the embodiment of the present invention;

[0026] Figure 8 Schematic structural diagram of the fluidized bed reactor in the embodiment of the present invention. Specific embodiments

[0027] The present invention will be further described in detail below in conjunction with the embodiments with reference to the drawings.

[0028] See Figures 1 to 7 Shown is a preferred embodiment of the gas distributor, which includes a distribution plate 1, a pipe cap 2, and a baffle 3.

[0029] A plurality of ventilation holes 11 are formed in the distribution plate 1. In this embodiment, the ventilation holes 11 are evenly distributed on the distribution plate 1. A snap ring 4 is arranged at intervals along the circumferential direction of the ventilation holes 11 below the distribution plate 1. The snap ring 4 is located at the edge of the ventilation holes 11, and the number of the snap rings 4 is 3.

[0030] The pipe cap 2 is hemispherical, is arranged below the distribution plate 1 with the cap opening facing upwards, the pipe cap 2 corresponds to each ventilation hole 11, and a plurality of air guide holes 21 are formed in the side wall of the pipe cap 2. In this embodiment, the number of the air guide holes 21 is 3 and they are evenly spaced along the circumferential direction of the pipe cap 2. As Figure 7 shown, the included angle between the 3 air guide holes 21 is 120°, and they are asymmetrically arranged along the center of the pipe cap, avoiding the impact of air flow and being more conducive to the uniform distribution of gas. The distance D from the center of the air guide hole 21 to the bottom of the pipe cap 2 is 1 / 3R, where R is the radius of the pipe cap 2. The pipe cap 2 is provided with snap blocks 5 at intervals along the outer peripheral wall. The snap blocks 5 are located within the snap ring 4. See Figure 2 shown. In this embodiment, the number of the snap blocks 5 is 6, which are arranged at the top of the pipe cap 2. The number of the snap blocks 5 is more than that of the snap ring 4, facilitating the adjustment of the fixing angle of the pipe cap 2 on the distribution plate 1.

[0031] The baffle 3 is arranged inside the pipe cap 2 and is located outside the air guide holes 21. A passage for gas to pass through is left between the baffle 3 and the air guide holes 21, and the gas discharged from the air guide holes 21 is downwardly deflected. In this embodiment, the baffle 3 is arc-shaped and is inclined downward along the upper edge of the air guide holes 21. The arc included angle α of the baffle 3 is 120°, the included angle β between the baffle 3 and the axis of the pipe cap 2 is 80°, and the length L of the baffle 3 is 2.5d, where d is the diameter of the air guide hole 21. In other embodiments, one end of the baffle 3 is inserted into the air guide hole 21 by closely adhering to the top wall of the air guide hole 21.

[0032] See Figure 8 Shown is a preferred embodiment of the fluidized bed reactor, which includes an upper shell 8 and a lower shell 6 connected to the upper shell 8.

[0033] The upper shell 8 is a hollow structure and serves as a reaction zone. A feed pipe 81 is disposed at the lower portion of the upper shell 8 and is inclined upward.

[0034] The lower shell 6 is a hollow structure, which is a ventilation area and communicates with the cavity of the upper shell 8. The lower shell 6 is connected to the upper shell 8 by a flange. The lower shell 6 includes an upper section 62 and a lower section 63 connected to the upper section 62. The upper section 62 is cylindrical, and the lower shell 6 is a cone with a diameter gradually decreasing from top to bottom. The distribution plate 1 is located at the top of the upper section 62, and the air inlet pipe 61 is arranged on the upper section 62 and below the distribution plate 1. The air inlet pipe 61 is transversely penetrated on the upper section 62, and a bend pipe 7 is arranged at the outlet end of the air inlet pipe 61. The outlet of the bend pipe 7 faces downward and is trumpet-shaped, and the outlet is located at the axis of the lower shell 6.

[0035] Working principle: The airflow enters the upper section 62 of the lower shell 6, flows downward into the lower section 63, and turns back to flow upward under the action of the conical shell; first it flows in along the air guide hole 21 on the pipe cap 2, and under the action of the baffle 3, the airflow direction changes to downward along the axis of the pipe cap 2 at 80°, and turns back through the concave surface of the pipe cap 2 to enter the reactor upper shell 8 and mix with the catalyst. Under the action of the gas distributor, the airflow is evenly filled into the upper shell 8, leaving no dead corners, and the gas velocity is approximately equal at all places in the entire cross section. On the other hand, the baffle 3 prevents solid materials such as catalysts from clogging the air guide hole 21, and avoids the phenomenon of excessive or too small local gas flow rate and uneven catalyst distribution. The reaction gas and catalyst in the fluidized bed reactor are fully mixed, the heat transfer effect is good, and the bed temperature is uniform, which can be controlled within a temperature range of 1 to 3°C.

Claims

1. A gas distributor, comprising a distribution plate (1), and a plurality of ventilation holes (11) are formed in the distribution plate (1). Characterized in that: It further includes a pipe cap (2) arranged below the distribution plate (1) with the cap opening upwards. The pipe cap (2) corresponds to the ventilation holes (11). A plurality of air guide holes (21) are formed in the side wall of the pipe cap (2). A baffle (3) is arranged inside the pipe cap (2) around the air guide holes (21). A passage for gas to pass through is left between the baffle (3) and the air guide holes (21), and the gas discharged from the air guide holes (21) is downwardly deflected; the baffle (3) is arc-shaped and is inclined downward along the upper edge of the air guide holes (21); the arc angle α of the baffle (3) is 120° - 150°, the angle β between the baffle (3) and the axis of the pipe cap (2) is 70° - 80°, the length L of the baffle (3) is 1.5d - 2.5d, where d is the diameter of the air guide holes (21); the pipe cap (2) is hemispherical, and the distance D from the center of the air guide holes (21) to the bottom of the pipe cap (2) is 1 / 3 - 1 / 2R, where R is the radius of the pipe cap (2).

2. The gas distributor according to claim 1, Characterized in that: The number of the air guide holes (21) is 3 and they are evenly spaced along the circumferential direction of the pipe cap (2).

3. The gas distributor according to claim 1, Characterized in that: Clamping rings (4) are arranged at intervals along the circumferential direction of the ventilation holes (11) below the distribution plate (1), and clamping blocks (5) are arranged at intervals along the outer peripheral wall of the pipe cap (2), and the clamping blocks (5) are located inside the clamping rings (4).

4. A fluidized bed reactor applying the gas distributor according to any one of claims 1 to 3, Characterized in that: It includes an upper shell (8) and a lower shell (6) connected to the upper shell (8). The cavities of the upper shell (8) and the lower shell (6) are communicated. A feed pipe (81) is arranged on the upper shell (8). The distribution plate (1) is located at the top of the lower shell (6), and an air inlet pipe (61) is arranged on the lower shell (6) below the distribution plate (1).

5. The fluidized bed reactor according to claim 4, Characterized in that: The feed pipe (81) is inserted obliquely upwards on the upper shell (8).

6. The fluidized bed reactor according to claim 4, Characterized in that: The air inlet pipe (61) is horizontally penetrated on the lower shell (6). A bent pipe (7) is arranged at the outlet end of the air inlet pipe (61). The outlet of the bent pipe (7) faces downwards and is flared, and the outlet is located at the axis of the lower shell (6).

7. The fluidized bed reactor according to claim 4, Characterized in that: The lower shell (6) includes an upper section (62) and a lower section (63) connected to the upper section (62). The upper section (62) is cylindrical. The distribution plate (1) is located at the top of the upper section (62). The air inlet pipe (61) is arranged on the upper section (62). The lower shell (6) is conical with a gradually decreasing diameter from top to bottom.

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