Common Types of Thermal Oxidizer (TOX) Systems

Common Types of Thermal Oxidizers (TOX)

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Direct Fired Thermal Oxidizers (DFTO)

Direct fired thermal oxidizers (DFTO), also known as afterburners, are the most basic type of thermal oxidizer technology. They have no heat recovery, therefore are expensive to operate in many applications. They are cost-effective in terms of both capital investment and maintenance and are most efficient in treating process air with high concentrations of volatile organic compounds.

DFTOs are common in batch processing applications or applications where heat can be captured from the exhaust for use in process heating or steam generation.

Regenerative Thermal Oxidizers (RTO)

Regenerative Thermal Oxidizers are the most popular air pollution control technology. They are known for their high reliability and long service life, while offering the lowest operating costs among thermal oxidizer systems. This is due to their reclaiming nearly 95% of the heat with its unique regenerative heat exchange.

Recuperative Thermal Oxidizers

Recuperative thermal oxidizers (TOX) feature an integrated air-to-air heat exchanger using the hot, clean air exiting the combustion chamber to preheat the incoming process air. This heat recovery reduces the fuel demand significantly.

Certain sectors whose processes generate moderate-to-high VOC emissions will incorporate TOX units, like the chemical and pharmaceutical industries. Though much heat still exists the exhaust stack, some applications can capture it for use in process heating, or steam generation.

Catalytic Recuperative Oxidizers

Catalytic recuperative oxidizers (CATOX), consume less fuel due to lower operating temperatures (typically between 600°F and 650°F) compared to other thermal oxidizer systems. They’re best used for clean applications that do not involve halogens, sulfur, silicone, or particulates.

CATOX units are most often used in sectors with VOC emissions that can be oxidized at lower temperatures, including coating, printing, and petrochemical industries.

Regenerative Catalytic Oxidizers (RCO)

Regenerative Catalytic Oxidizers function similarly to RTOs but incorporate a layer of catalyst-impregnated ceramic media, making them even more fuel-efficient. RCOs provide a long service life and are suitable for low-VOC process airstreams (below 16%).

Applications for using RCOs are often found in chemical, pharmaceutical, and coating industries.

VOC Rotary Concentrators

Although not oxidizers themselves or standalone solutions, VOC Rotary Concentrators pre-condition an airstream before it is sent to a paired oxidizer for VOC destruction. These concentrators adsorb VOCs from high-volume, low-VOC concentration process air and send these adsorbed VOCs, in a reduced airstream, to a thermal or catalytic or regenerative thermal oxidizer for final VOC destruction.

‍Learn more about the differences between thermal oxidizer types >>