A foam-resistant absorber level control system

Abstract

This invention discloses an absorber level control system to resist foam interference. It includes an overflow discharge interface pipe located below the flue gas inlet of the absorber wall, and a built-in defoaming chamber at the connection between the overflow discharge interface pipe and the absorber wall for eliminating foam in the slurry pool. By installing the built-in defoaming chamber at the overflow discharge interface pipe, this invention avoids the influence of foam in the absorber wall on the level control of the overflow discharge interface pipe, fundamentally eliminating foam interference with the overflow signal, solving the problem of false levels, and enabling the overflow operation of the absorber to be controlled according to the actual level of the slurry pool. Furthermore, this level control system eliminates the need for defoaming agents, reducing operating costs and avoiding secondary pollution from the introduction of chemicals.

Description

Technical Field

[0001] This utility model relates to the field of absorption tower liquid level control technology, specifically to an absorption tower liquid level control system that resists foam interference. Background Technology

[0002] Wet desulfurization is currently the most widely used flue gas desulfurization technology in coal-fired power plants and large industrial boilers. Its core principle is to use an alkaline absorbent slurry to chemically react with sulfur dioxide (SO2) in the flue gas in a scrubbing tower, thereby efficiently removing sulfur oxides.

[0003] A desulfurization absorption tower is typically a large, vertical cylindrical spray tower, mainly divided into several key functional zones: the flue gas inlet and outlet section, the spray scrubbing zone, and the slurry reaction zone. Raw flue gas enters from the lower part of the absorption tower, and clean flue gas exits from the top after passing through a demister. In the spray scrubbing zone, several spray layers are arranged horizontally in a staggered pattern, each equipped with multiple nozzles to atomize the limestone slurry delivered by the circulating pump into countless tiny droplets. These droplets form a huge gas-liquid contact surface area, thoroughly mixing with the counter-current flue gas and efficiently absorbing SO2. Below this, the slurry reaction zone is a large container used to store and oxidize the reaction products. An oxidation air pipeline is located here, with air blown in by a Roots blower to forcibly oxidize the calcium sulfite generated after capturing SO2 into the stable byproduct gypsum. A stirrer continuously operates to prevent slurry sedimentation and scaling.

[0004] Currently, wet desulfurization absorption towers typically control the maximum liquid level by installing overflow pipes on the sidewalls of the slurry tank to prevent backflow of slurry into the inlet flue of the absorption tower due to excessively high liquid levels. However, in actual operation, due to various reasons such as the bubbling effect of oxidizing air and high organic impurity content in the slurry, a large number of fine bubbles are generated in the slurry tank. When the bubble size becomes small enough, its rising speed becomes very slow, resulting in a large amount of bubbles remaining in the slurry tank and forming a relatively thick foam layer. These low-density bubbles accumulate in the upper space of the slurry tank and easily enter the overflow pipe. This causes the overflow pipe to start discharging before the actual liquid level of the absorption tower reaches the designed maximum limit, creating a "false liquid level" phenomenon. This not only leads to abnormal slurry loss, disrupts the water balance, increases water replenishment and reagent consumption, but may also cause operators to misjudge the liquid level, affecting desulfurization efficiency and even threatening safe production. Furthermore, when operators need to prevent overflows, the actual liquid level is often already far below the level required for normal operation. An excessively low operating liquid level will have a significant negative impact on limestone dissolution in the slurry tank, gypsum quality, and desulfurization efficiency. Conventional methods of adding defoamers are costly and provide a passive, delayed response, failing to address the root cause of the problem. Utility Model Content

[0005] Technical objective: To address the shortcomings of existing absorption towers that cannot accurately control slurry level due to foam interference, this utility model discloses an absorption tower level control system that resists foam interference.

[0006] Technical solution: To achieve the above technical objectives, the present invention adopts the following technical solution:

[0007] An absorber level control system for preventing foam interference includes an overflow discharge interface pipe on the tower wall located below the height of the flue gas inlet of the absorber. A built-in defoaming chamber for eliminating foam in the slurry pool of the absorber is installed at the connection point between the overflow discharge interface pipe and the absorber. The built-in defoaming chamber includes a lower inlet chamber, a middle defoaming chamber, and an upper defoaming chamber arranged sequentially from bottom to top along the slurry height direction. The outlet of the upper defoaming chamber is higher than the height of the overflow discharge interface pipe. The bottom of the lower inlet chamber is connected to the slurry pool. A baffle plate assembly for breaking up and aggregating bubbles is installed between the lower inlet chamber and the middle defoaming chamber. A defoamer is installed between the middle defoaming chamber and the upper defoaming chamber. The outlet of the upper defoaming chamber is connected to the internal space of the absorber.

[0008] Preferably, the baffle assembly of this utility model includes several baffles arranged parallel to each other along the liquid level height direction, forming a zigzag channel for bubble movement between adjacent baffle surfaces.

[0009] Preferably, the baffle plate of this utility model has a V-shaped structure, with both ends connected to the lower liquid inlet chamber and the middle defoaming chamber, respectively. Small bubbles are broken and collected into large bubbles after passing through the baffle plate and then enter the middle defoaming chamber.

[0010] Preferably, the lower liquid inlet chamber of this invention has a frustum structure that is wider at the top and narrower at the bottom, and the mating surface with the slurry has an inclined structure.

[0011] Preferably, the middle defoaming chamber and the upper defoaming chamber of this utility model are columnar structures.

[0012] Preferably, the tower wall overflow discharge interface pipe of this utility model is located in the upper defoaming chamber. The upper defoaming chamber is provided with a bubble guide plate at the position corresponding to the tower wall overflow discharge interface pipe to prevent bubbles from entering the tower wall overflow discharge interface pipe. The bubble guide plate covers the pipe opening area of ​​the tower wall overflow discharge interface pipe, so that the bubbles move upward in the upper defoaming chamber.

[0013] Preferably, the tower wall overflow discharge interface pipe of this utility model has an inverted U-shaped structure, with its end connected to the drainage ditch for discharging slurry, and a vent pipe is installed at the high point of the tower wall overflow discharge interface pipe, which is connected to the atmosphere.

[0014] Beneficial effects: The absorber level control system disclosed in this utility model, which is designed to resist foam interference, avoids the influence of foam in the absorber on the level control of the overflow discharge interface pipe by setting a built-in defoaming chamber at the overflow discharge interface pipe of the tower wall. This fundamentally eliminates the interference of foam on the overflow signal, solves the problem of false liquid level, and enables the overflow operation of the absorber to be controlled according to the actual liquid level of the slurry pool. Furthermore, the liquid level control system of this utility model does not require the use of defoaming agents, which reduces operating costs and avoids secondary pollution from the introduction of chemicals. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below.

[0016] Figure 1 This is a schematic diagram of the absorption tower structure of this utility model;

[0017] Figure 2 This is a structural diagram of the built-in defoaming chamber of this utility model;

[0018] Among them, 1-absorption tower flue gas inlet, 2-tower wall overflow discharge interface pipe, 3-lower section liquid inlet chamber, 4-middle section defoaming chamber, 5-upper section defoaming chamber, 6-slurry pool, 7-baffle plate group, 8-defoamer, 9-baffle plate, 10-bubble guide plate, 11-ditch, 12-vent pipe. Detailed Implementation

[0019] Reference will now be made in detail to embodiments of the present disclosure, one or more of which are set forth herein. Each embodiment and example is provided by way of explanation of the apparatus, composition, and materials of the present disclosure, and not by way of limitation. Rather, the following description provides convenient illustrations for implementing exemplary embodiments of the present disclosure. Indeed, it will be apparent to those skilled in the art that various modifications and variations can be made to the teachings of the present disclosure without departing from the scope or spirit of the present disclosure.

[0020] like Figure 1 and Figure 2As shown, this utility model discloses an absorber level control system for resisting foam interference, including a tower wall overflow discharge interface pipe 2 located below the height of the flue gas inlet 1 of the absorber. A built-in defoaming chamber for eliminating foam in the absorber slurry pool is provided at the connection between the tower wall overflow discharge interface pipe 2 and the absorber. The built-in defoaming chamber includes a lower inlet chamber 3, a middle defoaming chamber 4, and an upper defoaming chamber 5 arranged sequentially from bottom to top along the slurry height direction. The outlet of the upper defoaming chamber 5 is higher than the height of the tower wall overflow discharge interface pipe 2. The bottom of the lower inlet chamber 3 is connected to the slurry pool 6. A baffle plate group 7 for breaking and aggregating bubbles is provided between the lower inlet chamber 3 and the middle defoaming chamber 4. A defoamer 8 is provided between the middle defoaming chamber 4 and the upper defoaming chamber 5. The outlet end of the upper defoaming chamber 5 is connected to the space inside the absorber.

[0021] This invention utilizes a built-in defoaming chamber to eliminate foam at the overflow discharge interface pipe 2 on the tower wall, thereby avoiding interference with liquid level control and preventing slurry from flowing out with foam when the actual liquid level has not reached the overflow height, thus achieving precise control of the slurry level in the absorption tower. The lower inlet chamber 3, the middle defoaming chamber 4, and the upper defoaming chamber 5 of this invention are connected by flanges at the ends to form an integrated chamber structure. The bottom inlet of the lower inlet chamber 3 is the slurry inlet, and the upper part of the upper defoaming chamber 5 is the bubble outlet. The overflow discharge interface pipe 2 on the tower wall is located inside the upper defoaming chamber 5. The upper defoaming chamber 5 is equipped with a bubble guide plate 10 at the position corresponding to the overflow discharge interface pipe 2 on the tower wall to prevent bubbles from entering the overflow discharge interface pipe 2. The bubble guide plate 10 covers the pipe opening area of ​​the overflow discharge interface pipe 2 on the tower wall, causing the bubbles to move upward in the upper defoaming chamber 5. The top of the upper defoaming chamber is preferably designed to be 1 m higher than the normal operating liquid level.

[0022] like Figure 2 As shown, the baffle plate group 7 of this utility model includes several baffle plates 9 arranged parallel to each other along the liquid level height direction, forming a zigzag channel for bubble movement between the surfaces of adjacent baffle plates 9; the surface of the baffle plate 9 has a V-shaped structure, and its two ends are connected to the lower liquid inlet chamber 3 and the middle defoaming chamber 4 respectively. Small bubbles are broken and collected into large bubbles after passing through the baffle plate 9 and then enter the middle defoaming chamber 4, and then enter the upper defoaming chamber 5 through the defoamer. The increased bubble size increases the floating speed in the upper defoaming chamber 5. During the floating process, the bubble guide plate blocks the bubbles, reducing the number of bubbles entering the overflow discharge interface pipe 2 on the tower wall.

[0023] Meanwhile, in order to reduce the amount of foam entering the defoaming chamber, in the embodiments of this utility model, the lower liquid inlet chamber 3 is a frustum structure that is wider at the top and narrower at the bottom, while the middle defoaming chamber 4 and the upper defoaming chamber 5 are columnar structures. The frustum structure design of the lower liquid inlet chamber 3 has an inclined surface that mates with the slurry, and the bottom inlet area is small, so only a small amount of foam will enter with the slurry, thus reducing the amount of foam in the defoaming process.

[0024] The overflow discharge interface pipe 2 of this utility model has an overall approximately inverted U-shaped structure, with its end connected to the drainage ditch 11 for discharging slurry. A vent pipe 12 is installed at the high point of the overflow discharge interface pipe 2, and the vent pipe 12 is connected to the atmosphere. During overflow discharge, the liquid level in the absorption tower is controlled to not exceed the maximum liquid level limit through the overflow discharge interface pipe 2.

[0025] In use, as the slurry height rises, the slurry containing fine foam enters from the bottom opening of the lower inlet chamber 3. During its upward flow, it passes through the baffle assembly 7 and the defoamer 8, where small bubbles collide and aggregate under inertial force to form larger bubbles. After entering the upper defoaming chamber, as the bubble diameter increases, the upward velocity of the bubbles in the slurry pool significantly accelerates. The large bubbles return to the gas phase space of the absorption tower from the top opening of the upper defoaming chamber, while the defoamed and clarified slurry flows into the absorption tower slurry pool. The foam in the slurry is effectively removed, preventing it from entering the overflow discharge pipe and interfering with the liquid level judgment. Overflow only occurs when the liquid level actually exceeds the overflow pipe elevation. During the overflow process, the slurry flows from the overflow discharge interface pipe 2 on the tower wall into the trench 11. When the liquid level drops below the overflow height, the design of the vent pipe breaks the siphon effect generated by the slurry flow, preventing further discharge of the slurry.

[0026] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. An anti-foam interference absorbing column level control system characterized by, The system includes a tower wall overflow discharge interface pipe (2) located below the height of the flue gas inlet (1) of the absorption tower. An internal defoaming chamber for eliminating foam in the slurry pool of the absorption tower is provided at the connection between the tower wall overflow discharge interface pipe (2) and the absorption tower. The internal defoaming chamber includes a lower section liquid inlet chamber (3), a middle section defoaming chamber (4) and an upper section defoaming chamber (5) arranged sequentially from bottom to top along the slurry height direction. The outlet of the upper section defoaming chamber (5) is higher than the height of the tower wall overflow discharge interface pipe (2). The bottom of the lower section liquid inlet chamber (3) is connected to the slurry pool (6). A baffle plate group (7) for breaking and aggregating bubbles is provided between the lower section liquid inlet chamber (3) and the middle section defoaming chamber (4). A defoamer (8) is provided between the middle section defoaming chamber (4) and the upper section defoaming chamber (5). The outlet end of the upper section defoaming chamber (5) is connected to the space inside the absorption tower.

2. An anti-foam interference absorbing column level control system according to claim 1, wherein, The baffle assembly (7) includes several baffles (9) arranged parallel to each other along the liquid level height direction, forming a zigzag channel for bubble movement between adjacent baffles (9) surfaces.

3. An anti-foam interference absorbing column level control system according to claim 2, wherein, The baffle plate (9) has a V-shaped structure, and its two ends are connected to the lower liquid inlet chamber (3) and the middle defoaming chamber (4) respectively. Small bubbles are broken and collected into large bubbles after passing through the baffle plate (9) and then enter the middle defoaming chamber (4).

4. The absorber level control system against foam interference according to claim 1, characterized in that, The lower liquid inlet chamber (3) is a frustum structure that is wider at the top and narrower at the bottom, and the surface that mates with the slurry is inclined.

5. An anti-foam interference absorbing column level control system as defined in claim 1 wherein, The middle defoaming chamber (4) and the upper defoaming chamber (5) are columnar structures.

6. An anti-foam interference absorbing column level control system as defined in claim 1, wherein, The tower wall overflow discharge interface pipe (2) is located in the upper defoaming chamber (5). The upper defoaming chamber (5) is equipped with a bubble guide plate (10) at the position corresponding to the tower wall overflow discharge interface pipe (2) to prevent bubbles from entering the tower wall overflow discharge interface pipe (2). The bubble guide plate (10) covers the pipe opening area of ​​the tower wall overflow discharge interface pipe (2) so that the bubbles move upward in the upper defoaming chamber (5).

7. An anti-foam interference absorbing column level control system as defined in claim 1 wherein, The tower wall overflow discharge interface pipe (2) has an inverted U-shaped structure, and its end is connected to the slurry discharge trench (11). A vent pipe (12) is set at the high point of the tower wall overflow discharge interface pipe (2), and the vent pipe (12) is connected to the atmosphere.

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