A wet scrubber is sized according to the volume of contaminated air requiring treatment, the pollutants present, their concentrations and the required removal efficiency. Airflow is an important starting point, but an effective wet scrubber cannot be selected on airflow alone.
The chemical characteristics of the pollutants, operating temperature, moisture content and the amount of contact required between the contaminated air and scrubbing liquid all influence the final system design.
Exeon’s scrubX™ wet scrubber range includes modular systems for different industrial airflow requirements, with multiple units able to operate in parallel where larger volumes of contaminated air need to be treated.
How Does Airflow Affect Wet Scrubber Size?
The first consideration is normally the quantity of air that must be extracted from the process, vessel or building.
A small tank extraction system may require only a relatively modest airflow, while a waste reception building or large industrial process may involve many thousands of cubic metres of air per hour.
Exeon’s current scrubX™ range includes models with maximum individual airflow capacities from approximately 3,000m³/hr to 40,000m³/hr. For higher airflow requirements, scrubX™ units can be installed in parallel.
Determining the correct airflow is important because the extraction system must capture the contaminated air effectively while allowing sufficient treatment within the scrubber.
Why Does Pollutant Concentration Matter?
Two applications with identical airflow rates may require very different wet scrubber configurations if their contaminant concentrations differ.
For example, an air stream containing a relatively low concentration of ammonia presents a different treatment requirement from an equivalent airflow with substantially higher ammonia or hydrogen sulphide levels.
The type of pollutant also determines the scrubbing chemistry required. This means the air volume, contaminant concentration and chemical treatment requirements need to be considered together when sizing the system.
Applications such as anaerobic digestion emission control can also experience changing contaminant loads, making normal and peak conditions important during design.
What Other Factors Affect Wet Scrubber Sizing?
A complete wet scrubber design may consider:
- Normal and maximum airflow
- Pollutant type
- Normal and peak contaminant concentrations
- Required removal efficiency
- Temperature and humidity
- Scrubbing liquid chemistry
- Gas-to-liquid contact requirements
- Pressure resistance through the scrubber
- Fan duty and ductwork losses
- Available plant space
- Access for maintenance
- Requirements for chemical storage and liquid handling
These considerations help determine the size of the treatment tower, packing arrangement, liquid circulation rate and associated equipment.
The same principles apply within demanding applications such as wet scrubbing for food production and abattoirs, where emission loads can vary according to production activity.
Can Wet Scrubbers Be Installed in Parallel?
Yes. The modular nature of scrubX™ allows multiple scrubber units to operate in parallel when a single unit cannot provide the required treatment capacity.
Units can also be stacked where plant space is limited, allowing the treatment system to make more efficient use of the available footprint.
Wet scrubbing may also form one stage within a wider industrial odour and emission control system incorporating activated carbon or another treatment technology.
Correct sizing therefore begins with a detailed assessment of the air stream rather than simply choosing the nearest standard airflow capacity. By considering airflow, contaminant loading, chemistry, removal targets and site constraints together, Exeon can configure scrubX™ to provide efficient and reliable long-term industrial emission control.
Contact Exeon today to arrange a site consultation or request a tailored proposal. Our technical team will assess your airflow volumes and contaminant profile to design a system that delivers consistent emission control.