What is a Catalytic Recuperative Oxidizer?
A Catalytic Recuperative Oxidizer (often called catalytic oxidizer) destroys pollutants like Hazardous Air Pollutants (HAPs), Volatile Organic Compounds (VOCs), and odorous emissions that are often discharged during industrial processes.
Catalytic oxidizers achieve high VOC destruction efficiency by heating and maintaining a polluted airstream at temperature (typically 600 to 650F) for a set “dwell” time as it passes through catalyst material. The lower operating temperature of a catalytic oxidizer results in much lower fuel use than thermal recuperative oxidizers. VOC destruction efficiency can reach 99+%. Catalytic oxidizers can operate with an integral heat exchanger for fuel savings, or without a heat exchanger for capital cost savings.
Catalytic systems perform well in clean applications with no halogens, sulfurs, silicone, or particulates. These systems have a long life because they operate at a much lower temperature than thermal recuperative oxidizers.
The Three T’s of Catalytic Oxidizers – Time, Temperature and Turbulence
Note: Gas hourly space velocity (GHSV) is sometimes substituted for “time” when describing catalytic system performance. GSHV is the technical term for the ratio of treated airflow to catalyst volume for catalytic units. It is a critical value determining the performance and life expectancy of a catalytic system. High GHSV values represent lower performance and shorter catalyst life.
How does a catalytic oxidizer work?
A pollutant-laden airstream is pushed through the oxidizer, usually with a system fan (1). When equipped with an air-to-air heat exchanger, the flow of air will pass through the air-to-air heat exchanger (2) to preheat the air before entering the burner/combustion chamber (3). In the combustion chamber, the air is heated to a sufficiently high (>600F) temperature and then passes through the catalyst material (bed) (4) where VOCs are destroyed. The hot, cleaned air then continues through a hot pass of the heat exchanger (if heat exchanger is utilized) (5). The cooled, clean air is then exhausted to the atmosphere (6).
Advantages and disadvantages of catalytic systems over other technologies are discussed more completely here Selecting an Oxidizer.
Questions to ask when considering a catalytic recuperative Oxidizer (CATOX)?
- Is a catalytic oxidizer the most cost-effective oxidizer solution for my airstream?
- A heat exchanger is a cost-effective option for most applications
- For catalytic systems, plate or shell & tube heat exchangers will perform well
- Is there a potential for particulates?
- Catalytic systems do not handle particulates; consider other technologies
- VOC concentrations over 16% will require special consideration