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Home / Blog / Packed Column Scrubber: Design, Operation, Selection, Types & Column Packing

Packed Column Scrubber: Design, Operation, Selection, Types & Column Packing

A packed column scrubber (or scrubber tower) is a type of filtration system in which the column is filled with a specific material called «packing». This packing increases the surface area inside the column, promoting a more effective contact between the gas and the liquid.

Emission control systems are widely used in various industrial processes for cleaning gases from different contaminants such as acids, bases, organic compounds, and others.

Usage and Effectiveness

This is just a basic list of pollutants that column scrubbers can address. If you have doubts about the suitability of a column scrubber for your needs, please contact us.
Type of Pollutant
Acid Gases
Hydrogen chloride (HCl), sulfur dioxide (SO2), hydrogen fluoride (HF)
Alkaline Gases
Ammonia (NH3)
Volatile Organic Compounds (VOCs)
Removed through physical absorption or chemical reactions
Odorous Compounds
Hydrogen sulfide (H2S), mercaptans
Particulate Matter
Captured with suitable scrubbing liquids, despite primary design for gases
Specific Organic Compounds
Targeted based on scrubbing solution, e.g., formaldehyde, phenol
Halogenated Compounds
Removed through reactions with suitable scrubbing solutions
Other Reactive Gases
Chlorine (Cl2), ozone (O3)
It's important to note that the removal efficiency and the choice of scrubbing liquid will largely depend on the specific application, concentration, and the nature of the pollutant in the air stream.


The design of scrubbers will depend on its type. However, in any case, the construction includes the following elements:
  • Columnar unit where pollutant capture occurs;
  • Inlet nozzle;
  • Liquid supply pipeline;
  • Outlet nozzle;
  • Recirculation water storage tank;
  • Sludge discharge port.
In summary, a wet scrubber column is designed to maximize gas-liquid contact, facilitating efficient removal of pollutants from the air stream.

Design Fundamentals

Packed column scrubber design calculation considers:
  1. Flow Rate: Gauge the air volume for treatment, influencing the column's dimensions.
  2. Contaminants: Recognize the air's pollutants to choose the right scrubbing solution and packing.
  3. Mass Transfer: Based on substance properties, compute the mass transfer coefficient to assess pollutant transfer efficacy to the solution.
  4. Packing Material: For scrubber column design, pick a material ensuring optimal gas-liquid interaction and chemical resistance.
  5. Packing Height: Use various parameters to determine the needed height for removal efficiency.
  6. Pressure Drop: Estimate the pressure drop across the bed for smooth operation.
  7. Scrubbing Rate: Set the scrubbing solution flow for maximum effectiveness.
  8. Mist Eliminator: Design one to prevent droplet escape, considering gas flow and droplet size.
Remember, while these basics guide the packed column scrubber design, more specific formulas and considerations are needed per application and requirement.

Aspect Ratio

The aspect ratio of a scrubber column refers to the ratio of its height to its diameter. An optimal aspect ratio is crucial for the efficient performance of the filtration systems. Depending on the design and requirements, typical unit might have an aspect ratio ranging from 3:1 to 5:1, though this can vary based on the specific application and design considerations.

Packed Column Scrubbing Process

Tornado ST | Spray Tower Scrubber
In the packed column wet scrubber, the air stream passes through the column filled with packing and encounters the liquid (typically dripping from top to bottom through the packing). Contaminants in the gas are either absorbed into the solution or undergo a chemical reaction with it. The solution, now containing the absorbed or chemically altered pollutants, gathers at the tower's base and is then drained off.


The selection and calculation of an air purification device depend on many factors and require detailed analysis. We offer consultations free of charge. Please contact us if you need assistance in choosing purification systems.
Our commitment goes beyond just delivering a product. We offer:
  • Quick and Seamless Installation: Get started without a hitch, saving both time and effort.
  • Eco-friendly Operation: Experience minimal waste substances, emphasizing our dedication to a greener future.
  • Effortless Maintenance: Our cleaners are designed for straightforward operation, ensuring long-term reliability without the hassle.
  • Customized Material Selection: We prioritize safety and efficiency. Depending on the chemical contents and temperature of the gas, we tailor the material of the cleaner to your specific needs.
Trust in Torch-Air, where we prioritize the purity of the air you breathe. Choose us for an environment that is not just clean, but Torch-Air clean.


The design and functioning of scrubbing systems largely depend on its type and the specific requirements of the task at hand. Below, we delve into the characteristics and utilities of different filtration systems types.
• Packed Column Scrubber:
Uses packing material (Raschig rings, saddles, etc.) to increase the surface area for contact between the gas and liquid.
Air flows through the packing while the scrubbing liquid drips from top to bottom, facilitating counter-current contact.
Effective for removing soluble gases and particles from the air stream.
• Bubble Column Scrubber:
Gas is introduced at the bottom of the column, creating bubbles in the liquid.
When bubbles rise to the top of the column, contaminants from the air transfer into the solution.
Suitable for processes requiring intense mass transfer between the gas and the liquid.
• Plate Column Scrubber:
Contains a series of horizontal plates or trays through which the gas flows.
Solution is distributed on top of each plate, and air flows through openings in the plates, facilitating contact with the solution.
Particularly effective for large air flows.
• Venturi Scrubber Column:
Gas is accelerated through a narrow throat (Venturi section) where it mixes with the solution.
The intense acceleration of the air and its collision with the liquid droplets lead to high removal efficiency of particles.
Especially suitable for removing solid particles and large droplets from the air stream.
• Scrubber Absorption Column:
Operates based on the principle of either physical or chemical absorption.
The air stream is exposed to a liquid solvent that selectively absorbs specific contaminants from it.
Typically designed to optimize the contact between the gas phase and the liquid solvent for effective mass transfer.
Commonly used for the removal of gaseous pollutants like SO2, CO2, and volatile organic compounds.
It can be implemented in various designs, such as the packed column or the plate column, depending on the specific process and design requirements.
• CO2 Scrubber Column:
It removes carbon dioxide from air streams using chemical absorption, often with solvents like amines (e.g., MEA).
Designed for industries like power and chemical plants, the air stream, when passed through the scrubber column, sees CO2 binding with the solvent.
This solvent is later regenerated, typically via heating, to release CO2 and facilitate its reuse.
In applications where contaminants need to be thoroughly washed from the air stream, a scrubber washing column might be the preferred choice.

Technical Specifications

The technical specifications depend on the configuration. Determining the specifications is based on a detailed survey of the production and the nature of the pollutants. Each parameter can be adjusted according to the requirements of the customer, the production, and common sense.

When choosing a filter for production, it's important to consider several characteristics:
  1. Capacity. Selected based on the needs of production, a specific process, or equipment. For increasing capacity, filtration complexes can be used.
  2. Degree of Purification. The purity of the exiting gas. It can range from 90 to 99.99%.
  3. Power of a single fan.
  4. Capacity (tank) for the circulation of water and solutions (absorbers).
Vertical Scrubber With Random Packing
Vertical Scrubber With Random Packing

Scrubber Column Packing

Tower packing refers to the materials placed inside the tower to facilitate the interaction between the air and the solution for cleaning. Key points include:
Purpose: Increase the surface area for contact between the air and liquid, enhancing the efficiency of pollutant removal.
Materials: Common packing materials include Raschig rings, Pall rings, Berl saddles, and structured packing. They are often made of materials like plastic, metal, or ceramic.
Design: Packing shapes and sizes can vary, with specific designs optimizing for factors like pressure drop, surface area, and cost.
In summary, packing in a scrubber tower plays a pivotal role in ensuring effective gas-liquid contact, thus enhancing the scrubbing efficiency.

The efficiency of the scrubber column gas removal process is vital for minimizing environmental emissions and ensuring compliance with regulations.
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We always make extremely precise calculations and provide assistance in choosing the optimal cleaning systems, which usually takes 1 to 2 days.
Head of Engineering,
Vladimir Nikulin
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