Air flow distribution device for a fixed adsorption column

Abstract

The application provides a gas flow distribution device of a fixed adsorption and desorption tower, which comprises a pretreatment device, an adsorption tower, a gas flow distribution mechanism, an adsorbent layer, an adsorption fan and an exhaust cylinder. The outlet of the pretreatment device is connected with the inlet of the adsorption tower. The outlet of the adsorption tower is connected with the inlet of the adsorption fan. The outlet of the adsorption fan is connected with the inlet of the exhaust cylinder. The gas flow distribution mechanism and a plurality of layers of adsorbent layers are sequentially arranged in the adsorption tower from top to bottom. The gas flow distribution mechanism is provided with a plurality of uniform flow outlets which are uniformly distributed on the whole cross section of the adsorption tower and cover the surface of the adsorbent layer. The device can effectively improve the uniformity of gas flow distribution in the fixed bed during the desorption process, improve the desorption efficiency, reduce the desorption time, prolong the service life of the adsorbent and reduce the operation cost of the equipment.

Description

[Technical Field]

[0001] This invention relates to the technical field of volatile organic waste gas treatment, and in particular to an airflow distribution device for a fixed adsorption-desorption tower. [Background Technology]

[0002] Activated carbon or zeolite fixed beds are among the most critical components of VOCs treatment systems. Activated carbon has a large adsorption capacity and excellent adsorption effect; zeolite molecular sieves offer highly targeted adsorption and high desorption efficiency. The combination of activated carbon and zeolite molecular sieve fixed beds with CO, RTO, or RCO technologies is widely used in VOCs waste gas treatment, and the adsorption-desorption fixed bed is also crucial for the normal operation of the entire system.

[0003] However, currently on the market, fixed adsorption-desorption beds, due to various reasons and their unique structures, generally suffer from low desorption temperatures, incomplete desorption, unstable bed operation, and even smoldering. Activated carbon adsorption fixed beds, in particular, exhibit numerous problems. One major reason for this is uneven airflow distribution, leading to uneven temperature rise of the adsorbent, resulting in incomplete desorption and high VOC residue rates. During adsorption, due to the large adsorption airflow, the airflow distribution is relatively good, mainly because the adsorbent itself acts as a flow restrictor, ensuring uniform airflow distribution. Generally, the pressure drop of a fixed bed is between 500-1000 Pa. During the desorption process, due to the technological characteristics of the adsorption-desorption fixed bed, the desorption air volume is much lower than the adsorption air volume, generally between 10% and 20% of the adsorption air volume. This results in extremely uneven airflow distribution of the desorption air inside the fixed bed, incomplete desorption of the adsorbent, and a relatively high VOCs residue rate, which greatly reduces the adsorption capacity and service life of the adsorbent, and even causes smoldering due to VOCs residue. At the same time, the desorption concentration also varies greatly, which brings great difficulties to the actual operation.

[0004] In practical use, in order to ensure the normal operation of the adsorption-desorption fixed bed, the desorption temperature must be reduced, the desorption time extended, and the desorption efficiency decreased. As a result, the adsorption capacity of the adsorbent decreases rapidly with the increase of the number of desorptions, which seriously affects the normal use of the equipment. [Summary of the Invention]

[0005] The purpose of this invention is to solve the problems in the prior art and to propose an airflow distribution device for a fixed adsorption-desorption tower, which can effectively improve the uniformity of airflow distribution in the fixed bed during the desorption process, improve desorption efficiency, reduce desorption time, extend the service life of the adsorbent, and reduce the operating cost of the equipment.

[0006] To achieve the above objectives, the present invention proposes an airflow distribution device for a fixed adsorption-desorption tower, comprising a pretreatment device, an adsorption tower, an airflow distribution mechanism, an adsorbent bed, an adsorption fan, and an exhaust stack. The outlet of the pretreatment device is connected to the inlet of the adsorption tower, the outlet of the adsorption tower is connected to the inlet of the adsorption fan, and the outlet of the adsorption fan is connected to the inlet of the exhaust stack. The adsorption tower is provided with an airflow distribution mechanism and several layers of adsorbent bed from top to bottom. The airflow distribution mechanism has several uniform flow outlets that cover the entire cross-section of the adsorption tower, so that the desorption air covers the surface of the adsorbent bed.

[0007] Preferably, the airflow distribution mechanism employs a multi-point injector or a movable vortex plate assembly.

[0008] Preferably, the airflow distribution mechanism includes a desorption main pipe, desorption branch pipes, and flow equalization nozzles. The inlet end of the desorption main pipe is connected to the desorption gas for introducing the desorption gas into the adsorption tower. The outlet end of the desorption main pipe is connected to several desorption branch pipes, and several flow equalization nozzles are evenly distributed on the desorption branch pipes.

[0009] Preferably, the flow equalization nozzle is a pressurized nozzle with the nozzle facing downwards.

[0010] Preferably, the desorption branch pipes are symmetrically arranged on both sides of the desorption main pipe, and are perpendicular to the desorption main pipe and parallel to the horizontal plane.

[0011] Preferably, the airflow distribution mechanism includes a movable vortex plate, a connecting rod, and a driving mechanism. The movable vortex plate has uniformly spaced holes covering the entire cross-section of the adsorption tower. The adsorption tower is provided with a support base, and the movable vortex plate is movably mounted on the support base. One side of the movable vortex plate is connected to the driving mechanism via a connecting rod. Under the action of the driving mechanism, the movable vortex plate can be moved to the inside or outside of the adsorption tower.

[0012] Preferably, the adsorbent layer is made of one or more of activated carbon, zeolite molecular sieve, activated alumina, and silica gel.

[0013] Preferably, the inlet of the adsorption tower is provided with an adsorption inlet valve and a desorption outlet valve, the adsorption inlet valve being located between the outlet of the pretreatment device and the inlet of the adsorption tower, and the outlet of the adsorption tower is provided with an adsorption outlet valve and a desorption inlet valve, the adsorption outlet valve being located between the outlet of the adsorption tower and the inlet of the adsorption fan.

[0014] The beneficial effects of this invention are:

[0015] 1. By setting up an airflow distribution mechanism, the airflow distribution in the fixed bed during the desorption process is made more uniform.

[0016] 2. It can effectively improve desorption efficiency, make desorption more thorough, and extend the service life of the adsorbent.

[0017] 3. Because the desorption is more thorough and there is less VOC residue, the desorption temperature can be increased according to the temperature resistance of the adsorbent, thereby further enhancing the desorption process.

[0018] 4. Due to the improved desorption efficiency and extended adsorbent lifespan, operating costs are effectively reduced, while safety risks are avoided, ensuring long-term stable operation of the equipment.

[0019] The features and advantages of the present invention will be described in detail through embodiments and in conjunction with the accompanying drawings. [Attached Image Description]

[0020] Figure 1 This is a schematic diagram of the airflow distribution device of a fixed adsorption-desorption tower according to the present invention;

[0021] Figure 2 This is a front view schematic diagram of the airflow distribution mechanism according to Embodiment 1 of the present invention;

[0022] Figure 3 yes Figure 2 A top view of the airflow distribution mechanism;

[0023] Figure 4 This is a front view schematic diagram of the airflow distribution mechanism according to Embodiment 2 of the present invention;

[0024] Figure 5 This is a top view schematic diagram of the movable vortex plate in Embodiment 2 of the present invention.

[0025] Explanation of reference numerals in the attached figures:

[0026] 1-Pretreatment device, 2-Adsorption tower, 201-Adsorption inlet valve, 202-Desorption outlet valve, 203-Adsorption outlet valve, 204-Desorption inlet valve, 3-Airflow distribution mechanism, 301A-Desorption main pipe, 302A-Desorption branch pipe, 303A-Flow equalization nozzle, 301B-Modible vortex plate, 302B-Connecting rod, 303B-Drive mechanism, 4-Adsorbent layer, 5-Adsorption fan, 6-Exhaust stack.

Detailed Implementation Methods

[0027] Example 1

[0028] See Figures 1 to 3This invention discloses an airflow distribution device for a fixed adsorption-desorption tower, comprising a pretreatment device 1, an adsorption tower 2, an airflow distribution mechanism 3, an adsorbent layer 4, an adsorption fan 5, and an exhaust stack 6. The outlet of the pretreatment device 1 is connected to the inlet of the adsorption tower 2, the outlet of the adsorption tower 2 is connected to the inlet of the adsorption fan 5, and the outlet of the adsorption fan 5 is connected to the inlet of the exhaust stack 6. The adsorption tower 2 is provided with an airflow distribution mechanism 3 and several layers of adsorbent layer 4 arranged sequentially from top to bottom. The airflow distribution mechanism 3 has several uniformly distributed outlets covering the entire cross-section of the adsorption tower 2, so that the desorption air covers the surface of the adsorbent layer 4.

[0029] Further, see Figure 2 and Figure 3 The airflow distribution mechanism 3 adopts a multi-point injector, including: a desorption main pipe 301A, desorption branch pipes 302A and flow equalization nozzles 303A. The inlet end of the desorption main pipe 301A is connected to the desorption gas for introducing the desorption gas into the adsorption tower 2. The outlet end of the desorption main pipe 301A is connected to several desorption branch pipes 302A. Several flow equalization nozzles 303A are evenly distributed on the desorption branch pipes 302A.

[0030] Further, see Figure 2 and Figure 3 The flow equalization nozzle 303A is a pressurized nozzle with its nozzle facing downwards. The desorption branch pipes 302A are symmetrically arranged on both sides of the desorption main pipe 301A, and are perpendicular to the desorption main pipe 301A and parallel to the horizontal plane.

[0031] Furthermore, the adsorbent layer 4 is made of one or more of activated carbon, zeolite molecular sieve, activated alumina, and silica gel.

[0032] Furthermore, the inlet of the adsorption tower 2 is provided with an adsorption inlet valve 201 and a desorption outlet valve 202. The adsorption inlet valve 201 is located between the outlet of the pretreatment device 1 and the inlet of the adsorption tower 2. The outlet of the adsorption tower 2 is provided with an adsorption outlet valve 203 and a desorption inlet valve 204. The adsorption outlet valve 203 is located between the outlet of the adsorption tower 2 and the inlet of the adsorption fan 5.

[0033] Example 2

[0034] See Figure 4 and Figure 5The difference between Embodiment 2 and Embodiment 1 lies in the structure of the airflow distribution mechanism. Specifically, in this embodiment, the airflow distribution mechanism 3 adopts a movable vortex plate assembly, including: a movable vortex plate 301B, a connecting rod 302B, and a driving mechanism 303B. The movable vortex plate 301B has uniformly spaced holes covering the entire cross-section of the adsorption tower 2. The adsorption tower 2 is provided with a support base, and the movable vortex plate 301B is movably mounted on the support base. One side of the movable vortex plate 301B is connected to the driving mechanism 303B through the connecting rod 302B. Under the action of the driving mechanism 303B, the movable vortex plate 301B can be moved to the inside or outside of the adsorption tower 2.

[0035] The working process of this invention:

[0036] Adsorption operation: After dust removal and dehumidification by the pretreatment device 1, the waste gas enters the adsorption tower 2. During adsorption, the adsorption inlet valve 201 and adsorption outlet valve 203 are open, while the desorption outlet valve 202 and desorption inlet valve 204 are closed. The waste gas enters the adsorption tower 2 normally for adsorption. The adsorption tower 2 is equipped with an adsorbent layer 4. The organic waste gas is adsorbed and purified when passing through the adsorbent layer 4. The purified clean gas is then drawn by the adsorption fan 5 and discharged through the exhaust stack 6.

[0037] Desorption operation: When the adsorbent bed 4 is saturated with adsorption, close the adsorption inlet valve 201 and the adsorption outlet valve 203, and open the desorption inlet valve 204 and the desorption outlet valve 202 to desorb the adsorbent bed 4. Desorption is generally carried out by thermal desorption. The desorption gas with a certain temperature enters the adsorption tower 2 from the desorption inlet valve, and passes through the adsorbent bed 4 after being evenly distributed by the airflow distribution mechanism 3.

[0038] The airflow distribution mechanism 3 can employ a multi-point injector or a movable vortex plate assembly. The adsorbent layer 4 can utilize adsorbent materials such as activated carbon, zeolite molecular sieves, adsorbent alumina, and silica gel. Because the desorption air is evenly distributed across the surface of the adsorbent layer 4, the temperature distribution of the adsorbent material throughout the entire layer is uniform. During the entire desorption process, the adsorbent layer 4 exhibits high desorption efficiency, low VOCs residue, higher desorption temperature, and more thorough desorption. This effectively prevents safety accidents, ensures the adsorbent layer 4 maintains high adsorption capacity, extends its service life, reduces operating costs, and achieves energy conservation and emission reduction.

[0039] In Example 1, the airflow distribution mechanism 3 employs a multi-point injector, such as... Figure 2 , Figure 3As shown, the desorbed gas is introduced into the adsorption tower 2 through the desorption main pipe 301A, and then evenly distributed to each area through the desorption branch pipe 302A. The desorption branch pipe 302A is equipped with a flow equalization nozzle 303A. The nozzle is a pressurized nozzle. The flow equalization nozzle 303A is required to evenly cover the entire cross section of the adsorption tower 2, so that the desorbed air covers the entire surface of the adsorbent.

[0040] In embodiment 2, the airflow distribution mechanism 3 employs a movable vortex plate assembly, such as... Figure 4 , Figure 5 As shown, the support base of the movable vortex plate assembly can be installed inside the adsorption tower 2 using a flange or welding. The movable vortex plate 301B has uniformly spaced holes covering the entire cross-section of the adsorption tower 2. The differential pressure of the movable vortex plate 301B can be adjusted according to actual conditions, generally within 300-500 Pa. During adsorption, the movable vortex plate 301B is moved outside the tower by the connecting rod 302B and the drive mechanism 303B, allowing the adsorbed gas to pass normally through the adsorption tower 2. During desorption, the movable vortex plate 301B is moved inside the tower by the connecting rod 302B and the drive mechanism 303B. The desorbed gas, after passing through the movable vortex plate 301B, uniformly enters the surface of the adsorbent layer 4. When the high-temperature gas passes through the adsorbent layer 4, it desorbs the organic matter within the adsorbent layer 4 and is discharged from the desorption outlet valve 202. The discharged desorbed gas then undergoes further processing.

[0041] The above embodiments are illustrative of the present invention and are not intended to limit the present invention. Any simple modifications to the present invention are within the scope of protection of the present invention.

Claims

1. A gas flow distribution device for a fixed adsorption-desorption tower, characterized in that: The adsorption tower (2) includes a pretreatment device (1), an adsorption tower (2), an airflow distribution mechanism (3), an adsorbent bed (4), an adsorption fan (5), and an exhaust stack (6). The outlet of the pretreatment device (1) is connected to the inlet of the adsorption tower (2), the outlet of the adsorption tower (2) is connected to the inlet of the adsorption fan (5), and the outlet of the adsorption fan (5) is connected to the inlet of the exhaust stack (6). The adsorption tower (2) is provided with an airflow distribution mechanism (3) and several layers of adsorbent bed (4) arranged sequentially from top to bottom. The airflow distribution mechanism (3) has several uniformly distributed outlets covering the entire cross-section of the adsorption tower (2), so that the desorption airflow... The surface of the adsorbent layer (4) is covered; the airflow distribution mechanism (3) includes a movable vortex plate (301B), a connecting rod (302B) and a driving mechanism (303B). The movable vortex plate (301B) has uniformly opened holes, covering the entire cross section of the adsorption tower (2). The adsorption tower (2) is provided with a support base. The movable vortex plate (301B) is movably installed on the support base. One side of the movable vortex plate (301B) is connected to the driving mechanism (303B) through the connecting rod (302B). Under the action of the driving mechanism (303B), the movable vortex plate (301B) can be moved to the inside or outside of the adsorption tower (2).

2. The airflow distribution device for a fixed adsorption-desorption tower as described in claim 1, characterized in that: The airflow distribution mechanism (3) adopts a multi-point injector or a movable vortex plate assembly.

3. The airflow distribution device for a fixed adsorption-desorption tower as described in claim 1 or 2, characterized in that: The airflow distribution mechanism (3) includes a desorption main pipe (301A), desorption branch pipes (302A) and flow equalization nozzles (303A). The inlet end of the desorption main pipe (301A) is connected to the desorption gas, which is used to introduce the desorption gas into the adsorption tower (2). The outlet end of the desorption main pipe (301A) is connected to several desorption branch pipes (302A). Several flow equalization nozzles (303A) are evenly distributed on the desorption branch pipes (302A).

4. The airflow distribution device for a fixed adsorption-desorption tower as described in claim 3, characterized in that: The flow equalization nozzle (303A) is a pressurized nozzle with the nozzle facing downwards.

5. The airflow distribution device for a fixed adsorption-desorption tower as described in claim 3, characterized in that: The desorption branch pipe (302A) is symmetrically arranged on both sides of the desorption main pipe (301A), and is perpendicular to the desorption main pipe (301A) and parallel to the horizontal plane.

6. The airflow distribution device for a fixed adsorption-desorption tower as described in claim 1, characterized in that: The adsorbent layer (4) is made of one or more of activated carbon, zeolite molecular sieve, activated alumina and silica gel.

7. The airflow distribution device for a fixed adsorption-desorption tower as described in claim 1, characterized in that: The adsorption tower (2) is provided with an adsorption inlet valve (201) and a desorption outlet valve (202) at its inlet. The adsorption inlet valve (201) is located between the outlet of the pretreatment device (1) and the inlet of the adsorption tower (2). The adsorption tower (2) is provided with an adsorption outlet valve (203) and a desorption inlet valve (204) at its outlet. The adsorption outlet valve (203) is located between the outlet of the adsorption tower (2) and the inlet of the adsorption fan (5).

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