A combined rotary absorption tower defoaming device

Abstract

The application discloses a combined rotary absorption tower defoaming device, which is used for solving the problems of unstable operation, equipment corrosion and secondary pollution caused by foam accumulation in a wet desulfurization process. The device comprises multiple sets of grating type rectangular bubble breaking grids, which are uniformly distributed above the slurry on the inner wall of the absorption tower and synchronously rotate in the same direction through external electrodes. The bubble breaking grids cut and break the foam through physical cutting, and the rotation of the bubble breaking grids drives the surface layer of the slurry to form a directional circular flow, so that the foam continuously gathers in the defoaming area and is efficiently removed. The application adopts a pure mechanical defoaming mode and does not need to rely on chemical agents, and has the advantages of high efficiency (foam removal rate is greater than or equal to 90%), low energy consumption, stable operation and the like. In the preferred scheme, an intelligent control module is additionally arranged, the rotation speed and the spacing of the bubble breaking grids are dynamically adjusted through real-time monitoring of the foam thickness, and the device is further adapted to complex working conditions. The device can be widely applied to the foam treatment of desulfurization absorption towers in fields such as coal-fired power plants and chemical plants.

Description

Technical Field

[0001] This application relates to the field of flue gas desulfurization technology in coal-fired power plants, specifically to a combined rotary absorption tower defoaming device. Background Technology

[0002] In wet flue gas desulfurization (WFGD) processes, the absorber is one of the core pieces of equipment, used to react alkaline slurry (such as limestone slurry) with sulfur dioxide (SO2) in the flue gas to achieve efficient desulfurization. However, in actual operation, dust and organic matter carried in by the flue gas, desulfurizing agent, and process water often cause serious foaming problems within the absorber, leading to a series of negative impacts. Foam accumulation reduces gas-liquid mass transfer efficiency, affects the desulfurization effect, and can even cause the absorber liquid level to be falsely high, triggering false alarms or system tripping. In more serious cases, foam overflow may carry heavy metals, dust, and other pollutants, posing an environmental leakage risk.

[0003] Currently, industrial methods for controlling foam in absorption towers mainly employ physical and chemical approaches, such as adding defoamers. While these methods have some effect, they still have inherent limitations. For instance, physical defoaming methods can only temporarily suppress surface foam, failing to address the root cause and potentially increasing energy consumption and equipment wear. Traditional defoamers (such as silicones and polyethers) defoam by disrupting the foam film structure, but their effects are short-lived, requiring continuous addition. They cannot eradicate the foam generation mechanism, and long-term use can lead to agent residue. Excessive addition may alter slurry properties, affecting desulfurization efficiency and even introducing harmful components (such as increased COD). Furthermore, frequent additions increase operating costs, resulting in high overall operating expenses.

[0004] Therefore, there is an urgent need to develop a foam elimination device for wet desulfurization absorption towers that is simple in structure, low in operating cost, and has good defoaming effect, in order to solve the problems existing in the current technology and ensure the stable operation and desulfurization efficiency of the desulfurization system. Summary of the Invention

[0005] To address the aforementioned technical problems in existing technologies, the purpose of this application is to provide a combined rotary absorption tower defoaming device. This application utilizes multiple sets of synchronously rotating bubble-breaking grids, combined with directional flow control technology, to achieve efficient foam breaking and dynamic removal, including rotary bubble-breaking grids and a rotary drive system.

[0006] The technical solution adopted in this application is as follows:

[0007] The aforementioned combined rotary absorption tower defoaming device includes an absorption tower and multiple defoaming grids evenly spaced along the circumference of the inner sidewall of the absorption tower. Each defoaming grid is fixedly installed on the sidewall of the absorption tower by a rotary drive system, and the defoaming grid is located in the radial direction of the absorption tower. Under the driving action of the rotary drive system, the defoaming grid can rotate about the horizontal line as an axis. The defoaming grid is located above the slurry surface inside the absorption tower.

[0008] Furthermore, the bubble-breaking grid is positioned 150-300 mm above the slurry surface inside the absorption tower.

[0009] Furthermore, the bubble-breaking grid includes an outer frame and two layers of grid strips arranged on the outer frame, the two layers of grid strips being arranged in an alternating pattern to form a grid structure;

[0010] The bubble-breaking grid has an overall rectangular structure.

[0011] Furthermore, in the structure of the bubble-breaking grid, a hydrophilic coating is provided on the surface of the grid strips and the surface of the outer frame.

[0012] Furthermore, in the structure of the same layer of grid strips, the spacing between the grid strips is 30-80mm.

[0013] Furthermore, multiple inclined guide plates are evenly distributed along the circumference of the inner sidewall of the absorption tower, and each bubble-breaking grid is provided with a guide plate nearby.

[0014] Furthermore, the rotary drive system includes a central rotating shaft and a variable frequency motor. One end of the central rotating shaft is fixedly connected to the bubble-breaking grid, and the other end of the central rotating shaft extends to the outside of the absorption tower and is fixedly connected to the variable frequency motor. The bubble-breaking grid is rotated by the driving action of the variable frequency motor.

[0015] Furthermore, it also includes a foam thickness radar sensor, an online slurry viscosity detector, and a PLC control system. The foam thickness radar sensor and the online slurry viscosity detector are used to monitor the foam thickness and slurry viscosity in the absorption tower, respectively, and transmit the detection data signals to the PLC control system.

[0016] The foam thickness radar sensor is connected to the rotation drive system of each bubble-breaking grid via a PLC control system. When the monitored foam thickness is lower than the set value range, the PLC control system provides feedback and controls to reduce the rotation speed of the bubble-breaking grid driven by the rotation drive system. When the monitored foam thickness is higher than the set value range, the PLC control system provides feedback and controls to increase the rotation speed of the bubble-breaking grid driven by the rotation drive system.

[0017] Furthermore, the rotation speed of each bubble-breaking grid in the absorption tower is adjusted to 5-25 rpm under the action of the corresponding rotation drive system, and all bubble-breaking grids are driven to rotate synchronously in the same direction and at the same speed. Through the unidirectional rotation of the bubble-breaking grids, a directional circulation is formed on the surface of the slurry, which pushes the dispersed foam to concentrate in the bubble-breaking grid area. When the foam flows through the bubble-breaking grid, it is cut and broken by the grid bars. At the same time, the centrifugal force generated by the rotation accelerates the gas-liquid separation. The broken gas escapes, and the slurry falls back into the absorption tower.

[0018] Furthermore, the foam thickness inside the absorption tower is monitored. When the foam thickness is >200mm, the rotation speed of the foam breaking grid is adjusted to 20-25rpm; when the foam thickness is <50mm, the rotation speed of the foam breaking grid is adjusted to 5-8rpm; otherwise, the rotation speed of the foam breaking grid is adjusted to 10-15rpm.

[0019] Compared with the prior art, the beneficial effects achieved by this application are:

[0020] 1. Highly efficient defoaming: Through the synergistic effect of physical breaking and flow, the foam removal rate is increased to over 95%, and there is no need to rely on chemical defoamers.

[0021] 2. Stable operation: Directional circulation avoids localized foam accumulation, reduces the risk of artificially high liquid levels, and ensures desulfurization efficiency.

[0022] 3. Energy saving and environmental protection: Reduces the dosage of chemicals and energy consumption, produces no secondary pollution, and meets the requirements of green process. Attached Figure Description

[0023] Figure 1 This is a structural schematic diagram of a combined rotary absorption tower defoaming device according to this application;

[0024] Figure 1 In the middle: 1. Bubble breaking grid; 2. Central rotating shaft; 3. Variable frequency motor; 4. Guide plate; 5. Foam thickness radar sensor; 6. Slurry viscosity online detector; 7. PLC control system. Detailed Implementation

[0025] The present application will be further described below with reference to specific embodiments, but the scope of protection of the present application is not limited thereto.

[0026] Example: Comparison Figure 1

[0027] A combined rotary absorption tower defoaming device includes an absorption tower and a plurality of defoaming grids 1 evenly spaced along the circumference of the inner sidewall of the absorption tower. Each defoaming grid 1 is fixedly installed on the sidewall of the absorption tower by a rotary drive system, and the defoaming grid 1 is located in the radial direction of the absorption tower. Under the driving action of the rotary drive system, the defoaming grid 1 can rotate about the horizontal line as an axis. The defoaming grid 1 is located 150-300 mm above the slurry surface in the absorption tower, covering the main foam accumulation area on the surface of the slurry.

[0028] The bubble-breaking grid 1 includes an outer frame and two layers of grid strips arranged on the outer frame. The two layers of grid strips are arranged in an alternating pattern to form a grid structure. The bubble-breaking grid 1 is rectangular in shape. In the structure of the grid strips in the same layer, the spacing between the grid strips is 30-80mm.

[0029] A hydrophilic coating is applied to the surface of the grid strips of the bubble-breaking grid 1 and the surface of the outer frame of the bubble-breaking grid.

[0030] Preferably, the grid strips of the bubble-breaking grid 1 are connected to the outer frame by a quick-release connection, and the modular design of different sizes facilitates maintenance or replacement and adapts to different tower diameter requirements.

[0031] Preferably, multiple inclined guide plates are evenly distributed along the circumference of the inner sidewall of the absorption tower, and each bubble-breaking grid 1 is provided with a guide plate nearby. The guide plates are inclined at a certain angle to help enhance the circulation of the slurry surface.

[0032] Preferably, the rotary drive system includes a central rotating shaft 2 and a variable frequency motor 3. One end of the central rotating shaft is fixedly connected to the bubble-breaking grid 1, and the other end of the central rotating shaft extends to the outside of the absorption tower and is fixedly connected to the variable frequency motor. The bubble-breaking grid 1 is rotated by the driving action of the variable frequency motor.

[0033] Preferably, this application uses a variable frequency motor 3 to drive the bubble-breaking grid 1 to rotate, thereby achieving low-energy operation. Compared with full-tower stirring or high-pressure spraying, only the bubble-breaking grid needs to be driven to rotate at low speed, reducing energy consumption by more than 30%.

[0034] Furthermore, the combined rotary absorption tower defoaming equipment has the advantage of synergistic defoaming. The evenly distributed design of multiple sets of foam-breaking grids ensures that foam is treated without dead corners, achieving dynamic full coverage of the entire foam layer and avoiding local accumulation. Directional circulation avoids foam retention, and through flow enhancement, it improves the continuity of defoaming and reduces the "re-foaming" phenomenon of traditional mechanical defoaming.

[0035] This application also includes a foam thickness radar sensor 4, a slurry viscosity online detector 6, and a PLC control system 7. The foam thickness radar sensor 4 and the slurry viscosity online detector 6 are used to monitor the foam thickness and slurry viscosity in the absorption tower, respectively, and transmit the detection data signals to the PLC control system 7. The foam thickness radar sensor 4 is connected to the rotation drive system of each bubble-breaking grid 1 through the PLC control system 7. When the monitored foam thickness is lower than the set value range, the PLC control system 7 provides feedback and controls to reduce the rotation speed of the bubble-breaking grid 1 driven by the rotation drive system; when the monitored foam thickness is higher than the set value range, the PLC control system 7 provides feedback and controls to increase the rotation speed of the bubble-breaking grid 1 driven by the rotation drive system.

[0036] The application process of the combined rotary absorption tower defoaming equipment described in this application includes: adjusting the rotation speed of each defoaming grid 1 in the absorption tower to 5-25 rpm under the action of the corresponding rotary drive system, and driving all defoaming grids 1 to rotate synchronously in the same direction and at the same speed. Through the unidirectional rotation of the defoaming grids, a directional circulation is formed on the surface of the slurry, which pushes the dispersed foam to concentrate in the defoaming grid area. When the foam flows through the defoaming grid, it is cut and broken by the grid bars. At the same time, the centrifugal force generated by the rotation accelerates the gas-liquid separation. The broken gas escapes, and the slurry falls back into the absorption tower.

[0037] Preferably, the rotation speed is adjustable (usually 5 to 25 rpm) to adapt to different foam viscosities and slurry conditions.

[0038] This application monitors the foam thickness inside the absorption tower. When the foam thickness is >200mm, the rotation speed of the foam breaking grid 1 is adjusted to 20-25rpm; when the foam thickness is <50mm, the rotation speed of the foam breaking grid 1 is adjusted to 5-8rpm; otherwise, the rotation speed of the foam breaking grid 1 is adjusted to 10-15rpm.

[0039] Example 1:

[0040] This embodiment provides a combined rotary absorber defoaming device, which is mainly used for eliminating foam on the surface of the slurry in wet desulfurization absorbers.

[0041] The combined rotary absorption tower defoaming device of this embodiment includes the following contents and methods:

[0042] The bubble-breaking grid module includes a rectangular outer frame and two layers of grid strips arranged alternately on the rectangular outer frame to form a grid structure. The grid strips are made of 316L stainless steel with a spacing of 50mm. The dimensions of a single unit of the rectangular outer frame are 2m long × 0.5m wide. The surfaces of the grid strips and the outer frame are coated with a hydrophilic coating, which improves the corrosion resistance of the materials themselves and assists in foam rupture through the hydrophilic material.

[0043] Four sets of bubble-breaking grid modules are set up and evenly distributed along the circumference on the inner wall of the 10m diameter absorption tower. The installation height is 200mm above the slurry surface inside the absorption tower.

[0044] Each set of bubble-breaking grids has its central shaft extending to the outside via a mechanical seal on the tower wall. It is driven by a 1.5kW variable frequency motor, with four motors controlled synchronously. The set speed is 10 rpm, rotating clockwise.

[0045] Multiple inclined guide plates are evenly distributed along the circumference of the inner sidewall of the absorption tower. Each bubble-breaking grid is equipped with a guide plate to help enhance the surface circulation of the slurry.

[0046] Operational results: Under the cutting action of the defoaming grid and the circulation, the foam layer gathers from the tower wall towards the center. After breaking, the gas is discharged through the exhaust port at the top of the tower, and the liquid falls back into the slurry of the absorption tower. The measured foam layer thickness was reduced from the original 500mm to less than 50mm, the defoaming efficiency reached 90%, and there was no chemical residue.

[0047] Example 2:

[0048] The structure of the combined rotary absorption tower defoaming device in Example 2 is the same as that in Example 1, except that: in Example 2, a total of 6 sets of defoaming grid modules are set up, which are evenly distributed along the circumference on the inner wall of the absorption tower with a diameter of 10m, and the installation height is located 300mm above the slurry surface.

[0049] Example 2 is equipped with an intelligent monitoring system. A foam thickness radar sensor and an online slurry viscosity detector are installed inside the absorption tower to transmit data to the PLC control system in real time. The motor speed is adaptively driven by the PLC and dynamically adjusted between 5 and 20 rpm: when the foam thickness is >200 mm, the speed increases to 20 rpm; when the foam thickness is <50 mm, the speed decreases to 5 rpm.

[0050] Operational Results: When the efficiency of the electrostatic precipitator decreases, leading to a surge in foam, the system automatically switches to an enhanced defoaming mode to prevent operational problems in the desulfurization system caused by artificially high liquid levels. It saves 40% more energy than traditional fixed-speed equipment and reduces annual maintenance costs by 60%.

[0051] Defoaming efficiency 90％ 95％ Energy consumption Medium (fixed speed) Low (adaptive adjustment) Maintenance requirements Clean the fence bars regularly Self-cleaning coating, maintenance-free design Applicable Scenarios Small and medium-sized desulfurization towers Large / Extreme Condition Desulfurization Tower .

[0052] The contents described in this specification are merely an enumeration of the implementation forms of the application concept, and the scope of protection of this application should not be regarded as limited to the specific forms described in the embodiments.

Claims

1. A combined rotary absorption tower defoaming device, characterized in that, The absorption tower includes a plurality of bubble-breaking grids (1) evenly spaced along the circumference of the inner sidewall of the absorption tower. Each bubble-breaking grid (1) is fixedly installed on the sidewall of the absorption tower by a rotary drive system, and the bubble-breaking grid (1) is located in the radial direction of the absorption tower. Under the driving action of the rotary drive system, the bubble-breaking grid (1) can rotate about the horizontal line as the axis. The bubble-breaking grid (1) is located above the slurry surface inside the absorption tower.

2. The combined rotary absorption tower defoaming device as described in claim 1, characterized in that, The bubble-breaking grid (1) is set at a position 150-300 mm above the slurry surface inside the absorption tower.

3. The combined rotary absorption tower defoaming device as described in claim 1, characterized in that, The bubble-breaking grid (1) includes an outer frame and two layers of grid strips arranged on the outer frame, the two layers of grid strips being arranged in an interlaced manner to form a grid structure; The bubble-breaking grid (1) is a rectangular structure.

4. The combined rotary absorption tower defoaming device as described in claim 3, characterized in that, In the structure of the bubble-breaking grid (1), a hydrophilic coating is provided on the surface of the grid strips and the surface of the outer frame.

5. The combined rotary absorption tower defoaming device as described in claim 3, characterized in that, In the same layer of grid strip structure, the spacing between the grid strips is 30-80mm.

6. The combined rotary absorption tower defoaming device as described in claim 1, characterized in that, Multiple inclined guide plates are evenly distributed along the circumference of the inner sidewall of the absorption tower, and each bubble-breaking grid (1) is provided with a guide plate nearby.

7. The combined rotary absorption tower defoaming device as described in claim 1, characterized in that, The rotary drive system includes a central rotating shaft (2) and a variable frequency motor (3). One end of the central rotating shaft is fixedly connected to the bubble-breaking grid (1), and the other end of the central rotating shaft extends to the outside of the absorption tower and is fixedly connected to the variable frequency motor. The bubble-breaking grid (1) is rotated by the driving action of the variable frequency motor.

8. The combined rotary absorption tower defoaming device as described in claim 1, characterized in that, It also includes a foam thickness radar sensor (4), a slurry viscosity online detector (6), and a PLC control system (7). The foam thickness radar sensor (4) and the slurry viscosity online detector (6) are used to monitor the foam thickness and slurry viscosity in the absorption tower, respectively, and transmit the detection data signals to the PLC control system (7). The foam thickness radar sensor (4) is connected to the rotation drive system of each bubble-breaking grid (1) via a PLC control system (7). When the monitored foam thickness is lower than the set value range, the PLC control system (7) provides feedback and controls to reduce the rotation speed of the bubble-breaking grid (1) driven by the rotation drive system. When the monitored foam thickness is higher than the set value range, the PLC control system (7) provides feedback and controls to increase the rotation speed of the bubble-breaking grid (1) driven by the rotation drive system.

Images