What is a Thermal Oxizider?
A Thermal Oxidizer (often referred to as TOX, incinerator, or afterburner) destroys pollutants like Hazardous Air Pollutants (HAPs), Volatile Organic Compounds (VOCs), and odorous emissions that are often discharged during industrial processes.
Thermal oxidizers achieve very high VOC destruction efficiency by heating and maintaining a polluted airstream at high temperature for a set dwell time. Typical VOC reduction destruction is 99+%. Thermal oxidizers can operate with an integral heat exchanger for fuel savings or without for capital cost savings. All oxidizer technologies achieve VOC destruction by exposing pollutant-containing air to a high temperature, for a set period of time, in a turbulent flow path.
The Three T’s – Time, temperature and turbulence
The Three T’s are critical and co-dependent factors that determine oxidizer performance. Thermal oxidizer systems perform well when treating high VOC concentration airstreams. The RTO utilizes a heat exchanger when VOC concentrations are below 25% LFL due to the significant fuel use in a thermal oxidizer. For very high VOC concentration (>25% LFL) airstreams, a heat exchanger is not required. VOC concentration of less than <15% LFL would be better treated using a regenerative thermal oxidizer (RTO).
How Does a Thermal Oxidizer Work?
A pollutant-filled airstream is pushed through the oxidizer, usually with a system fan. When equipped with an air-to-air heat exchanger, the flow of air will pass air through the air-to-air heat exchanger to preheat the air before entering the burner/combustion chamber. In the combustion chamber the air is heated to a sufficiently high (>1400F) temperature and held at this temperature with some amount of turbulence to ensure VOC destruction.
Typical operating temperatures are >1400F, with dwell times of 0.5-1 second to convert over 99% of the VOCs to carbon dioxide and water vapor. This hot, clean air then continues through a hot pass of the heat exchanger (if heat exchanger is utilized). The cooled, clean air is then exhausted to the atmosphere.
Questions to Ask When Considering a Thermal Oxidizer (TOX)?:
- Is a thermal oxidizer the most cost-effective oxidizer solution for my airstream?
- Due to the reliable, efficient performance of regenerative thermal oxidizers (RTO), thermal oxidizers are now selected for only a fraction of industrial applications (see Selecting an Oxidizer)
- Is my VOC concentration greater than 25% LFL: Heat exchanger needed or not?
- High VOC (high BTU) airstreams may not require a heat exchanger
- High VOC (high BTU) airstreams may require a special burner or flame arrestor
- Will a plate heat exchanger or shell and tube style heat exchanger be a better choice?
- Shell and tube heat exchangers are much heartier than plate style heat exchangers at the high temperatures seen in thermal oxidizers
- Is there a potential for particulates that could plug the heat exchanger?
- Shell and tube heat exchangers are better than plate for particulate applications
- Tube size is an important consideration when particulates are expected
- Is there a need for heat or steam in your plant?
- Secondary heat recovery has good payback with thermal oxidizers
- Do local codes require Low NOX operation?
- Low NOx burners can be retrofit for these applications.
The Kono Kogs philosophy is to provide innovative air pollution control technologies that provide the lowest cost, most reliable solution to our valued customers. We offer engineering, equipment manufacturing, installation, startup and post-sale service.
Other benefits to working with Kono Kogs:
- 24 Hour customer service and support (phone: 920-615-8804)
- Multiple OEM & technology offerings ensure unbiased recommendations
- Complete aftermarket sales department
- Management with over a century of oxidizer manufacturing and service experience