Exeon’s hi-flo™ activated carbon system works by extracting contaminated air from a building, vessel or industrial process and passing it through a deep bed of activated carbon. Odorous gases and airborne pollutants are captured by the carbon before the treated air is discharged through an exhaust stack.
The system combines controlled extraction, dust pre-filtration, even airflow distribution and carefully selected activated carbon media. Together, these stages help provide reliable treatment of contaminants including hydrogen sulphide (H₂S), ammonia, mercaptans, volatile organic compounds (VOCs) and other industrial odours.
The process works by passing contaminated air through specially selected activated carbon. Activated carbon has an extremely porous internal structure, giving it a large surface area onto which gaseous pollutants can attach through a process known as adsorption.
Unlike absorption, where a substance is taken into another material, adsorption causes contaminant molecules to collect on the surface of the carbon. The treated air can then continue through the system before being safely discharged.
Exeon’s hi-flo™ activated carbon system uses deep-bed activated carbon adsorption to provide industrial odour and emission control across applications with both significant airflow volumes and demanding contaminant loads.
How Is Contaminated Air Extracted?
The first stage is capturing contaminated air at source.
Extraction fans draw air from the building or process area and transport it through ductwork towards the hi-flo™ treatment unit. Maintaining suitable extraction is important because odorous air needs to be captured before it can escape into surrounding working areas or the outside environment.
This approach is used in a range of industrial odour and emission control systems, including wastewater treatment, waste handling and anaerobic digestion applications.
At some facilities, maintaining negative pressure within an enclosed process building can also help prevent uncontrolled odour escaping through doors and openings.
Why Does the Air Pass Through Dust Pre-Filtration?
Where particulate matter is present, contaminated air passes through a dust filtration stage before reaching the activated carbon.
Removing dust helps protect the carbon bed from contamination and blockage. If excessive particulate matter builds up within the media, it can restrict airflow, increase system pressure and potentially shorten the effective life of the activated carbon.
The hi-flo™ system can incorporate individually sealed, accessible dust filters so they can be inspected and maintained without disturbing the carbon bed.
This is particularly valuable in demanding waste handling applications, where tipping, sorting, shredding and storage processes may generate both odours and airborne dust.
How Does Activated Carbon Remove the Odour?
After pre-filtration, the air is distributed evenly through a deep bed of activated carbon.
Activated carbon contains an extensive network of microscopic pores, creating a very large internal surface area. As contaminated air passes through these pores, pollutant molecules are attracted to and retained on the carbon surface. This process is known as adsorption.
Exeon explains the process in more detail on its activated carbon air treatment page.
Correct airflow distribution and contact time are essential. The hi-flo™ carbon bed creates controlled resistance that helps distribute the air evenly through the media rather than allowing it to follow an easier path around sections of the bed.
What Happens to the Treated Air?
Once the air has passed through the activated carbon, centrifugal extraction fans move the treated air onwards for discharge through the exhaust stack.
The principle can be seen in Exeon’s wastewater transfer station odour control project, where a twin-layer hi-flo™ activated carbon system, pre-filter and extraction fan were used to treat an air stream containing high H₂S levels before atmospheric discharge.
The precise hi-flo™ configuration depends on airflow, contaminant concentrations, required contact time and the carbon media selected. Multiple modules can also operate in parallel where larger industrial air volumes need to be treated.
By controlling each stage from extraction and pre-filtration through to adsorption and final discharge, hi-flo™ provides a complete approach to treating contaminated industrial air rather than relying on the carbon media alone.