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Packed Bed Wet Scrubber: Working, Efficiency, Maintenance, and Advantages and Disadvantages

Operation

How does a packed bed scrubber work? Well, it is equipment that uses wetted packing material to improve gas-liquid contact. Inside the device, the media is placed on a special grate called a grid. In the upper part of the apparatus, a spray device consisting of various types of sprinklers and nozzles is installed.

The polluted stream enters the device through its lower part. It moves from bottom to top, passing through the wetted surface of the media, and exits through a pipe in the upper part of the apparatus. The liquid drains and collects in a hopper, from where it is discharged through a water trap. If the packed bed scrubber is working under increased gas pressure, a float regulator (trap) is installed to maintain the required fluid level in the hopper.

Horizontal Scrubber BOREAS-P2

Industrial Uses

Wet absorbers are widely used for cleaning industrial emissions, as well as for cooling and humidifying air.

Applications:

SO2, SO3, NOx, CO, H2S in the petrochemical and metallurgical industries
NH3, HF, H2SO4, H3PO4 in chemical plants producing fertilizers
Paint, polymer production from volatile organic compounds
Pulp and paper industry from Cl2, ClO2, Cl2O, HCl
After waste incineration
Hydrocarbons from oil refining enterprises
Cleaning acidic, alkaline, and toxic emissions from chemical plants

Diagram

Below is a packed bed scrubber diagram that illustrates the structural components of the unit.

Inlet Duct: Located at the bottom of the device, where the polluted stream enters.
Grid or Support Plate: Provides even distribution of the fill material throughout the tower.
Filling Material: Positioned on the grid, it can be in the form of randomly arranged elements (e.g., Raschig rings) or structured forms (e.g., corrugated sheets).
Spray Setup: Installed at the top of the equipment, including various types of spray nozzles and sprinklers.
Outlet Duct: Located at the top of the device.
Liquid Collection Hopper: Located at the bottom, where the fluid collects before being discharged through the water seal.
Water Seal or Trap: Positioned at the bottom, where the spent fluid is discharged from the device. Prevents the escape of pollutants.
Float Regulator: Installed in the hopper for automatic control of the fluid level.

Scheme

Main Types of Designs

A random packed bed tower scrubber is versatile and cost-effective, suitable for a broad range of applications with varying conditions. However, it may have higher pressure drops and less uniform contact. Common examples include Raschig rings, Pall rings, or Berl saddles. They are randomly arranged within the tower. These fill materials are typically small and come in shapes such as cylindrical or saddle-like, and they are dispersed throughout the column. We manufacture industrial packed bed scrubbers with both movable and stationary media.

TORNADO FB Fluidized Bed Scrubber

Performance: 100 — 175 000 cfm

Horizontal BOREAS-P3 Wet Scrubber with Random Packings and an Enlarged Column

Performance: 100 — 175 000 cfm

Horizontal Scrubber BOREAS-P2 with Random Packings

Performance: 100 — 175 000 cfm

Venturi TORNADO-FB fluidized Bed Scrubber With a Venturi Tube

Performance: 600 — 30 000 cfm

TORNADO RP Vertical Scrubber with Random Packing

Performance: 600 — 24 000 cfm

Constructively, installations of this type require larger dimensions and a more powerful fan. The column can be positioned either vertically or horizontally, with horizontal positioning allowing for a more compact equipment arrangement. In addition to counterflow columns, a packed bed fume scrubber with crossflow irrigation is also used in practice. In these devices, the fill material is typically inclined at 7–10° in the direction of the air flow to ensure better wetting of the surface.

We supply modular packed bed scrubber systems. Adding modules affects the overall performance, volume of filtered air, dimensions, and other technical specifications. This is very convenient and practical.

TORNADO SP Packed Bed Scrubber with Structured Packing

Performance: 600 — 30 000 cfm

Structured packed bed wet scrubbers provide higher efficiency, lower pressure drops, and better mass transfer, making them ideal for applications requiring precise control and optimal performance. However, they come at an increased expense and necessitate more careful installation. Arranged in a specific geometric pattern, such as corrugated sheets or other structured forms, these fill media are designed to create an increased surface area and provide more controlled flow.

The bed scrubber factory Torch-Air provides advanced solutions for industrial air filtration needs.

Purpose of Filling Material

Create a Large Surface Area: Increases the contact surface between water and gases, which speeds up heat exchange.
Form Winding Channels: Creates convoluted paths for the gases to extend their travel distance and increase contact time.
Act as a Filter: Functions to capture dust from the atmosphere.

TORNADO-FB

Advantages and Disadvantages

The high popularity of this equipment demonstrates all the advantages of a packed bed scrubber. Let’s list the main ones.

High cleaning efficiency: The large contact surface between phases ensures effective removal of pollutants.
Flexibility in choosing filling elements: A variety of media allows optimizing the design for specific conditions.
Low operating costs: Lower pressure drops and energy consumption compared to Venturi.
Minimal formation of secondary pollutants: Reduces the need for additional cleanup mechanisms.
Wide range of applications: Effective for removing particulate matter and gaseous pollutants, including VOCs and H2S.
Corrosion resistance: Made from corrosion-resistant materials for handling aggressive substances.
Does not require elevated water pressure.

These advantages make a packed bed chemical scrubber a versatile and efficient solution for industrial applications.

Disadvantages:

When handling large volumes of dust, the contact components can become clogged. This significantly increases the hydraulic resistance to air flow and reduces the equipment's performance.
Demands careful monitoring and control to maintain optimal performance and prevent issues such as flooding or channeling.
Higher pressure drops across packed bed scrubbers compared to some other types, which can lead to increased energy consumption.

Working with an experienced packed bed scrubber manufacturer can help you avoid common pitfalls and optimize your setup’s efficiency.

Commentary by air purification expert Michael Klepik

Maintenance

Packed bed scrubber maintenance is crucial for maintaining efficiency and prolonging the lifespan of the equipment. Here are the necessary maintenance tasks:
Weekly:

Visual inspection through inspection ports without stopping the equipment to check the condition of the spray and working fluid circulation systems.
Visual inspection through inspection ports without stopping the equipment to check the tank with recirculating fluid.

Quarterly:

Testing the condition of the spray and working fluid circulation components under different operating modes.
Checking the recirculating liquid tank for sludge loading.
Checking the automation controls for proper operation.

Annually:

Stop the equipment and visually inspect all parts for wear and tear or imminent failure: spray systems, fluid circulation, pumps, fans, and automation.

Troubleshooting

Effective packed bed scrubber troubleshooting can quickly identify and resolve issues, ensuring the unit continues to operate at optimal performance.

Key Factors Affecting the Efficiency of a Packed Bed Scrubber:

Incorrectly chosen media will reduce contaminant absorption. In this case, it will be necessary to re-purchase the appropriate components.
Too high or too low a flow rate can decrease the level of purification. It's essential to maintain an optimal balance for maximum contact.
Different contaminants require specific reagents for effective removal, and their concentration affects the degree of purification.
These parameters can affect the reactivity of chemicals and the overall efficiency of the process.
Uneven distribution can lead to a reduction in cleaning quality due to insufficient contact between phases.
Regular cleaning and maintenance of the unit are necessary to prevent clogging and maintain optimal purification efficiency.

Price Formation

To estimate the cost of a packed bed scrubber, you need to consider the following factors:
1. Design Specifications:

Higher flow rates require larger devices, which increase costs.
Greater concentrations of contaminants may demand quire more robust or specialized designs.
The choice of materials (e.g., stainless steel, FRP) impacts durability and expense.

2. Packing Elements:

Different types of materials (e.g., plastic, ceramic, metal) have varying costs.
The amount needed depends on the size of the bed scrubber.

3. Operating Conditions:

Extreme conditions may necessitate more expensive materials and design modifications.

4. Auxiliary Equipment:

Essential for the operation of the unit, and their specifications will impact the overall cost.
Necessary for monitoring and maintaining optimal performance.

5. Installation and Maintenance:

Labor and equipment needed for setting up the emission control system.
Regular upkeep and operational expenses, including energy and consumables.

TORNADO-FB Torch-Air

6. Compliance and Regulations:

Meeting specific regulatory standards may require additional features or certifications, adding to the expense.

7. Vendor and Location:

Prices vary between suppliers based on quality, reputation, and location.
Costs associated with transporting the unit to the installation site.

To get a precise estimate, you may need to contact suppliers with detailed specifications of your requirements, or use cost estimation software that factors in all these variables.

Choosing the right bed scrubber supplier is essential for ensuring the quality and reliability of your air purification system. We have extensive experience in manufacturing equipment. We are ready to answer all your questions and provide expert advice to help you choose the most suitable solution for your needs.

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