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What is a Catalytic Oxidizer (CatOx)?

A catalytic oxidizer, also referred to as a recuperative catalytic oxidizer, is an air pollution control system that uses catalyst to treat process exhaust. By using catalyst in the equipment, oxidation is accomplished at much lower temperatures than straight thermal oxidation. These systems are most appropriately used in process applications that have lower concentrations of Volatile Organic Compounds (VOCs). Catalytic oxidizers are capable of maintaining continuous steady-state operating conditions for nearly indefinite periods. With few moving parts and constant stable operating pressures and temperatures, a properly designed catalytic oxidizer easily achieves a greater than 99% destruction rate efficiency of VOCs.

Catalytic Oxidizer Gas Train-side viewStack, Catalytic Oxidizer + Controls-system view

How does a Catalytic Oxidizer Work?

First, the process air enters the oxidizer chamber and is heated before it passes through the catalyst.  The air is heated to the appropriate catalyst activation temperature which varies, depending on the VOC and type of catalyst, and can range from 350 F to 650 F. Exposure of the dirty air to the catalyst in the presence of excess oxygen at the necessary temperature ensures the high destruction of VOCs converting the VOCs into carbon dioxide, water vapor and thermal energy. When incorporating a heat exchanger, the process air first enters the heat exchanger and is pre-heated using the oxidizer’s exhaust energy prior to entering the oxidizer chamber.

Typical Catalytic Thermal Oxidizer P&ID

Typical Catalytic Thermal Oxidizer P&ID (Right click image to open in new tab)


Benefits of Catalytic Oxidizers

Catalytic oxidizers are an excellent air pollution control option in applications that need to treat low VOC process streams. Compared to other pollution control technologies they are very cost-effective, exceptionally reliable, have a low impact on the manufacturing process, and generate less NOx and CO.

Gas usage is a primary consideration in the ongoing operating cost of any thermal oxidizer. Oxidizers using a catalyst require less gas since oxidation of the VOCs is achieved at much lower temperatures compared to other thermal oxidizers. The lower gas consumption results in reduced gas combustion products of NOx, CO and CO2. In some cases, the heat recovery is sufficient for the treatment process to operate “auto-thermally” meaning that the energy evolved from the VOC destruction is sufficient to raise the process gas to the desired catalyst activation temperature and that no auxiliary fuel is necessary. An electric catalytic oxidizer uses electricity rather than gas and may be considered a more sustainable solution. 

Catalytic oxidizers have few moving parts and are reliable. By comparison, regenerative thermal oxidizers (RTOs) have frequent valve movements and can negatively impact operations due to back pressure fluctuations. Frequent valve cycling on the RTOs leads to higher maintenance, lower reliability and fugitive emissions at the valves. Due to the higher operating temperatures of thermal oxidizers, higher grade metals are typically required which increases the cost of materials.


Compare Regenerative Thermal Oxidizers (RTO) vs Catalytic Thermal Oxidizers (Catox)


Catalytic Oxidizer Automated Controls

Pollution Systems understands the importance of easy-to-use and easy-to-understand industrial controls that guarantee proper operation of the system and its desired outcome. Our systems are fully automated to easily start, stop and safely operate the equipment for minimal required operator interaction.  They include a control panel with a PLC and operator interface, safety interlocks and necessary instrumentation for continuous operation. Our experienced engineers work with our clients to design a set of robust system controls tailored to the specific application and preferences.  Some of the many options include remote interfacing and monitoring, data collection, and hazardous area classification. If you are looking to repair your existing Catalytic Oxidizer, our technical services division PolSys Services can assist in repairing the make and model of any Catalytic Oxidizer system.  


Catalytic Oxidizer Case Studies

Catalytic Oxidizer for Odor Control Case Study

Catalytic Oxidizer for Ethylene Oxide Exhaust Case Study

Catalytic Oxidizer Used in Solar Panel Manufacturing Case Study


Common Catalytic Oxidizer Industrial Applications

Some of the more common industrial applications for catalytic oxidizers include:


 Catalytic Oxidizer Ductwork & Oxidizer Stack-top viewClick Photo to see Gallery


As a catalytic oxidizer manufacturer, Pollution Systems will evaluate your air control requirements and provide you with the appropriate air treatment for your process application. The systems we offer focus on the lifetime cost of ownership by carefully selecting the equipment combined with high-quality designs and construction. Contact us to evaluate your air treatment issue and recommend the best path forward. 

Contact us HERE to request a quote from Pollution Systems.
If you would like to speak directly to our sales department you may call 832-730-1209 or email us at sales@pollutionsystems.com