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What is the gas scrubber?

Views: 23     Author: Xicheng EP LTD     Publish Time: 2023-04-25      Origin: Xicheng EP LTD

The gas scrubber is an industrial exhaust air filter whose main function is to neutralize harmful components in industrial air or exhaust streams, such as preventing fumes that have irritating effects or cause odor nuisances. Harmful gases and particulate dust must be removed from the air stream during the scrubbing process before the gas can be released into the open air. In some cases, the use of gas scrubbers also makes it possible to recover certain raw materials after processing. A great advantage is the versatility of gas scrubbers in different fields, including chemical industry, pharmaceutical industry, electronics manufacturing and furniture making industry, etc.


The device works by bringing the airflow into intimate contact with the scrubbing fluid. As a result of this contact, some gaseous components dissolve and remain in the water. There is thus a transfer of components from the gas phase to the liquid phase, also known as absorption. The solubility of the particle in the liquid will determine the extent to which the gaseous components dissolve into the liquid phase.

exhaust gas scrubber system


Therefore, it is very important to use the correct fluid as an absorbent. In addition to water, different acid-base neutralizing agents need to be used for different acid-base gases. Gas scrubbers are generally made of high-strength corrosion-resistant materials, and can usually be used to treat corrosive exhaust gas.


Exhaust gas scrubbers are an effective air pollution control device that is used worldwide. It can minimize air pollution, thereby reducing disasters caused by air pollution.

design a wet scrubber


Air scrubbers or gas scrubbers mainly consist of the following components:


1. Gas scrubber (packed tower)

2. Packing (structured or loose, Pall rings, Raschig rings, ...)

3. Defogging layer

4. Nozzle or liquid dispenser

5. Water pump

6. Chemical dosing device

7. Measurement and control equipment (pH, redox)

8. Hydration system


Components to separate out of industrial emissions are

H2S hydrogen sulfide

  • H2S (hydrogen sulfide)

  • NH3 (ammonia)

  • HCl (hydrochloric acid)

  • SO2 (sulfur dioxide)

  • RHS (mercaptans or thiols)

  • CH2O (formaldehyde, formaline)

  • Amines

  • Phenol

  • HNO3 (nitric acid)

  • NOx (nitrogen oxide)

  • EO (ethylene oxide)


How the gas scrubber process works?

Gas scrubbing is a process used to remove pollutants such as gases, chemicals, and particulates from industrial waste streams before they are discharged into the environment. Gas scrubbers work by passing a contaminated gas stream through a scrubbing liquid, which absorbs or reacts with the contaminants.


The basic process of gas scrubber includes the following steps:

1. The waste gas is collected centrally and introduced into the waste gas scrubber.

2. Contaminated gases enter the scrubber and come into contact with the scrubbing liquid.

3. The scrubbing liquid, which can be water or a chemical solution, traps or reacts with the contaminants in the gas stream.

4. The purified gas is introduced into the next processing link, and can be discharged directly if the emission standard is met.

5. After washing, the detergent will be stored in the water tank under the scrubber and can be recycled.


Gas scrubbing is an effective method of reducing the discharge of harmful pollutants into the environment, making it an important process in industrial settings.


Gas scrubber design steps

Determine the characteristics of the gas flow: Before designing a gas scrubber, it is important to understand the characteristics of the gas flow, such as temperature, pressure, flow rate, and composition.


Determine the Contaminants or Impurities to Remove: The type of contaminants or impurities in the gas stream will determine the type of scrubber to use. For example, packed bed scrubbers can be used to remove particulate matter, while venturi scrubbers can be used to remove gases such as sulfur dioxide.


Determine desired efficiency: The efficiency of a scrubber depends on the desired level of contaminant or impurity removal. Efficiency can be measured by the outlet concentration of pollutants or impurities.


Selecting a Scrubber Type: Depending on the nature of the airflow and the type of contaminant or impurity to be removed, select the appropriate type of scrubber. Common types of scrubbers include packed bed scrubbers, venturi scrubbers, and impingement plate scrubbers.


Scrubber Sizing: Scrubber sizing depends on the flow rate of the airflow and the type of scrubber selected. Dimensions can be calculated based on empirical equations or by computer simulation.

Exhaust gas scrubber production


Select Scrubber Material: The scrubber material should be compatible with the airflow and the type of contaminant or impurity to be removed. Common materials include stainless steel, PP (polypropylene), and fiberglass.


Add Auxiliary Equipment: Auxiliary equipment such as water pumps, activated carbon adsorbers, fans, and mist eliminators may be required to run the scrubber effectively.


Determine a maintenance schedule: Regular maintenance is required to keep your scrubber running at peak efficiency. The maintenance schedule should be determined according to the type and operating conditions of the scrubber.

Wet and Dry Scrubbers - The Difference

Dry scrubbers use adsorbents, such as dry adsorbent materials such as activated carbon, to absorb and remove pollutants from industrial exhaust air. When the gas passes through the activated carbon, the organic waste gas or odor gas components will be adsorbed, and finally the clean gas will be discharged. It can be used to treat VOC exhaust gas and odor control.

Gas adsorption equipment


The wet scrubber removes the acid-base content and dust in the exhaust gas through the contact of the gas and the detergent, and the neutralization reaction. Not only are they used for gas scrubbing, but they also excel as dust collectors, simplifying and enhancing dust suppression and control. Wet scrubber is multi-functional, and can be used in a variety of environments through the combination of different equipment, and the waste gas treatment efficiency can reach more than 85%.

Spray scrubber


Which industries can use air scrubbers?


  • Aquaculture

  • Chemical industry

  • Sewage treatment plant

  • Pharmaceutical Industry

  • Food industry

  • Animal food

  • Fertilizer production and processing

  • Garbage transfer station

  • Electronics manufacturing

  • Furniture manufacturing factory

  • Paint shop

  • Laboratory ventilation

  • Electroplating plants and pickling plants


When scrubbers are used optimally, very high removal efficiencies of harmful gas particles can be achieved. This means that fumes released into the outdoor air are no longer damaging to the environment.


What are the advantages of gas scrubbers?

1. Relatively simple and easy to control

2. Low running cost

3. Compact and space-saving

4. High purification efficiency and stable operation

5. Can be customized according to needs

6. Low maintenance cost

7. Multi-applicability, can be used to treat a variety of waste gases


What are the disadvantages of gas scrubbers?

  • During the operation process, a large amount of waste water will be generated

  • Requires large amounts of water and chemicals

  • Not suitable for operation in low temperature environment

  • Requires regular cleaning and maintenance

  • For some odor control applications, a prior pilot test may be recommended


What is the scrubber packing?

Scrubber packing is usually made of materials such as PP plastic, metal or ceramics, and is designed to provide a large surface area for gas-liquid contact. Packing can be arranged in various configurations, including random packing and structured packing.


Random packing consists of randomly arranged packing sheets that create a tortuous path for gas to pass through. This increases the contact time between the gas and the scrubbing liquid, allowing for more effective removal of contaminants. Examples of random fill materials include ceramic rings, PP plastic Raschig rings, and metal Pall rings.


PP polyhedral ball packingPolyhedral spherical packing inside packed bed scrubber

Structured packing, on the other hand, consists of an ordered arrangement of packing materials that make the airflow through the packing more uniform. This can lead to more efficient gas-liquid contact and higher mass transfer rates. Examples of structured packing materials include corrugated metal sheets and woven wire mesh.


The choice of packing material and configuration depends on factors such as the type and concentration of contaminants to be removed, the flow rate of the gas, and the nature of the scrubbing fluid. Gas scrubber design must also take into account factors such as pressure drop and the likelihood of packing fouling or clogging.

XICHENG EP LTD gas scrubbing solutions set the standard

  1. Each gas scrubber system is custom-made to the precise specifications of the customer.

  2. Provide detailed exhaust gas treatment solutions for each customer.

  3. Use professional-grade mechanical design software CAD to reduce errors.

  4. Provide free quotation list and design drawings.

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