How Thermal Oxidizers Work
Learn more about how Thermal Oxidizers function
Thermal oxidizers efficiently eliminate hazardous pollutants from industrial exhaust streams by using high-temperature oxidation to convert them into harmless byproducts.
The 3 T’s of Thermal Oxidizers: Time, Temperature & Turbulence
TOX typically have a 0.5 second to 1.0 second dwell time for most applications.
Typically 1400 F minimum up to 1550 F depending upon the VOC characteristics.
VOCs must combine with oxygen and heat to trigger the chemical reaction that breaks them down into CO2 and H2O. There are many successful thermal oxidizer designs that ensure sufficient turbulence, such as introducing the process air at an angle to induce spin or creating internal choke points. The better the mixing and heat distribution, the higher the VOC destruction.
How Do Thermal Oxidizers Work?
- A pollutant-filled airstream is pushed through the oxidizer, usually with a system fan. If the process airstream doesn’t have enough oxygen for combustion, ambient air is added.
- The flow of air passes through an air-to-air heat exchanger (if equipped) to preheat the air before entering the burner/combustion chamber. Thermal oxidizers can operate with an integral heat exchanger for fuel savings, or without one for capital cost savings.
- In the combustion chamber the air is heated to a sufficiently high temperature and held at high temperature with turbulence, to ensure VOC destruction. Typical operating temperatures are >1400°F, with dwell times of .5 – 1.0 second. This combusts the VOCs into CO2 and H2O.
- The hot, clean air continues through the hot pass of the heat exchanger (if equipped).
- Cooled, clean air is then exhausted to the atmosphere.
Operation
Thermal Oxidizers (TOX) are designed to control air pollution by oxidizing volatile organic compounds (VOCs) and hazardous air pollutants (HAPs) at high temperatures, typically between 1400°F and 1450°F. This high-temperature combustion process ensures that the pollutants are oxidized into less harmful substances, such as carbon dioxide and water vapor, before being released into the atmosphere. The process involves heating the exhaust stream to the required temperature and maintaining it for a sufficient residence time to ensure complete oxidation.
Destruction Efficiency
TOX units are highly efficient, often achieving VOC destruction efficiencies exceeding 99%. This high level of performance is attained by driving the airstream to high temperature for a sufficient residence time, usually between 0.5 to 1 second. The combination of high temperature, turbulence and adequate residence time ensures that the VOCs and HAPs are thoroughly oxidized.
Energy Consumption
The high operating temperatures of TOX units result in significant energy consumption. A heat exchanger is incorporated to capture heat before the cleaned airstream exits the thermal oxidizer. For light concentration air streams heat exchanger efficiencies of 70% are typical. Also, secondary heat exchangers are utilized to recapture more heat, typically for re-use in process heating. However, advancements in technology have led to the development of regenerative thermal oxidizers (RTOs), which incorporate very high efficiency heat recovery (95% typ) to reduce energy demand. RTO systems may be an alternative to a TOX in many cases.
Get more information on RTO systems.
Applications
Thermal oxidizers are versatile and can handle medium to high VOC concentrations. They are commonly used in industries such as petrochemical, pharmaceutical, and waste management, where effective emission control is critical. The ability to operate efficiently across a wide range of conditions makes TOX units suitable for diverse industrial applications. Whether dealing with high or low concentrations of pollutants, TOX units provide reliable and effective air pollution control, ensuring compliance with environmental regulations.
Contact Kono Kogs today for further help deciding what oxidizer is best for your needs. Our expert team is ready to help.
