What is a Wet Scrubber?
A wet scrubber is an air pollution control system that captures and neutralizes pollutants from exhaust gas streams using liquid. The system sprays a scrubbing liquid into contaminated air, causing the pollutants to dissolve or be trapped in the liquid before being safely removed. The goal is that the gas emerges without the former pollutants and contaminants.
Why Choose a Wet Scrubber?
Wet scrubbers are ideal for industries that emit acidic gases, volatile organic compounds (VOCs), dust, and fine particulate matter. They are commonly used in chemical processing, food production, consumer goods, materials and semiconductor plants.
Wet scrubbers offer multiple benefits when capturing and neutralizing pollutants, such as:
Dual Functionality: Removes both gaseous and particulate pollutants.
Compact Design: Water’s cooling effect allows for smaller equipment by reducing gas volume and minimizing the need for extra cooling systems.
Regulatory Compliance: Ensures emission limits are met for industrial emissions control.
Explosion Safety: Reduces risk by neutralizing combustible dust and vapors.
Types of Wet Scrubbers
Different industries require specific scrubber designs based on their emissions. The most common types include:
Quencher Scrubbers: Used for high-temperature exhaust gas cooling before additional scrubbing. Known for its high efficiency up to 99,9% removal. Combines a ‘quencher stage’ to cool hot gas with a ‘scrubbing stage’ to remove gases and vapors.
Packed Bed Scrubbers: Best for absorbing acid gases such as NOx and sulfur dioxide. They are frequently used in Chemical, Food Production, Fertilizer Plants and Materials manufacturing.
Venturi Scrubbers: Ideal for removing fine particulate matter with high collection efficiency. Here the Venturi forces dirty gas to move to a higher velocity when it collides with the scrubbing liquid. The liquid captures particles through mainly impact and diffusion.
Spray Tower Scrubbers: Suitable for large gas volumes with lower pollutant concentrations.
Energy Recovery Scrubber: A Venturi Scrubber, developed by JOA to combine handling emissions with recovering waste heat with heat exchangers. An additional integration with a Heat Pump can lead to higher temperatures.
Advantages & Disadvantages of Wet Scrubbers
When considering pollution control technologies, wet scrubbers offer a range of advantages and disadvantages. They are widely used in industries to reduce harmful emissions by using a liquid, typically water, to capture and neutralize pollutants. This makes them particularly effective for handling gas streams with high moisture content or soluble contaminants. However, like any system, wet scrubbers come with trade-offs.
Advantages:
Handles High Temperatures & Moisture: Suitable for high-temperature exhaust gas applications. Also highly humid gas streams can be treated.
Compact System Design: Cooling flue gases reduces overall system size. Smaller space requirements or footprint may lead to lower capital costs.
Removes Both Gases & Particles: More versatile than many dry scrubbers. Relatively small dust particles can be captured with the right droplet size.
Neutralizes Corrosive Gases: Prevents damage to downstream equipment.
Explosion Safety Benefits: Reduces fire and explosion risks in volatile environments. Using most liquids eliminates the possibility of explosions.
Disandvantages:
Corrosion Risk: Requires corrosion-resistant materials due to constant liquid exposure.
Slurry Waste Management: Requires proper handling and disposal of liquid waste. Must often be treated before discharge.
Electrical Energy Consumption: Uses more electrical power than Regenerative Thermal Oxidizers (RTOs).
Energy requirements for pumps and blowers. Some designs have higher pressure drops that require more energy.
Refilling Scrubbing Liquid: Even though a lot of the scrubbing liquid can be reused, It always needs to be replenished over time.
Proven Process: A Clear 4-Step Plan
Our proven approach consists of advising, designing, building and implementing tailor-made solutions:
Pre-Engineering Study
Design & Engineering
System Realization
Ready to optimize? Book a meeting with a Specialist
Start with a Pre-Engineering Study and learn how our proven process can enhance your performance, safety, and compliance. Let us help you design, realize, and maintain the perfect solution tailored to your needs for air filtration, energy recovery and more.
After implementation, we take care of ‘Preventive Maintenance’, ‘Remote Monitoring’ and Service & Spare Parts so that your wet scrubber continues to perform optimally over time.
Clients That Trust JOA
Leading manufacturers, chemical plants, and food processing companies rely on custom wet scrubber solutions to achieve environmental compliance and operational efficiency at the same time. We are proud to work with a wide range of the largest industrial manufacturers with the most comples production processes, worldwide.
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Wet Scrubber FAQ
A wet scrubber is an air pollution control device that removes gases and particulate matter from industrial exhaust streams using liquid.
Learn more about wet scrubbers
Wet scrubbers work by spraying a liquid into contaminated air, capturing pollutants before they exit through an exhaust stack. Most common solvents for wet scrubbers are water, Sodium Hydroxide (NaOH), Calcium Hydroxide (Ca(OH)2), Sodium Carbonate (Na2CO3 and Ammoina (NH#). We call wet scrubbers not using water (H2O) also ‘Chemical Scrubbers’. Read our detailed blog on how wet scrubbers work
Wet scrubbers generally have a higher efficiency rate for pollutant removal compared to dry scrubbers. They use liquid solutions to capture and neutralize pollutants, making them effective for both gases and particulates. In contrast, dry scrubbers rely on dry reagents or absorbents to remove pollutants without water, making them suitable for applications where water use is a concern.
Yes, especially when using packed bed scrubbers, which can absorb NOx gases with chemical solutions. By conducting a Pre-Engineering Study, we will dive deep into all substances that need to be removed and what solutions, dimensions, and other specifics lead to the best results.
Industries such as chemical processing, food manufacturing, pharmaceuticals, metal processing, and power generation use wet scrubbers for emissions control.
The biggest problem with wet scrubbers is the management of wastewater and sludge. Since they use liquid solutions to capture pollutants, they generate contaminated water that requires proper treatment and disposal. This adds to operational complexity, maintenance costs, and potential environmental concerns. Additionally, wet scrubbers can cause corrosion in equipment due to constant exposure to moisture and chemicals.
The main difference between a wet scrubber and an electrostatic precipitator (ESP) lies in how they remove pollutants. A wet scrubber uses liquid, usually water or a chemical solution, to capture and neutralize pollutants from gas streams, effectively removing both gases and particulate matter. In contrast, an ESP removes only particulate matter by charging particles with an electrical field and collecting them on oppositely charged plates. While wet scrubbers are better for handling gaseous pollutants and acidic gases, ESPs are more efficient for capturing fine dust and particulate emissions without generating wastewater.
