An Afterburner destroys Volatile Organic Compounds (VOCs) and Hazardous Air Pollutants (HAPs), that are created through chemical processes found in industrial exhaust streams. The Afterburner destroys these emissions through the process of combustion. The chemical process of thermal oxidation is quite simple; the exhaust stream temperature is raised to between 1,250 to 1,800°F, a temperature at which the chemical bonds that hold the molecules together, are broken. The VOCs in the process exhaust stream are converted to various combinations of carbon dioxide (CO2), water (H2O), and thermal energy by the high temperature of the combustion chamber. The Direct Fired Thermal Oxidizer, which is the most widely used abatement technology for industrial processes that produce exhaust streams with high levels of pollutants, can achieve over 99% hydrocarbon destruction rate.
These Afterburners are 2 Types they are
- Direct Flame Afterburners
- Catalytic Combustion Systems
Direct Flame Afterburners
Direct Flame afterburners are widely considered to be a more cost sensitive option, compared to other chemical abatement systems,
- Solid, in-house construction, for extended use
- No flame visibility
- Quicker start-up
- Typically, one of the most affordable option for pollution control equipment
- DFAs can also be more fuel efficient, when combined with heat exchangers, and downstream boilers.
- Long service life
- Minimal heat emitted
- Minimal noise pollution
- Smokeless combustion
- Custom designs, ready to use, that allow room for expansion, and system flexibility.
- Multiple safety shut-offs and features
- User friendly
Catalytic Combustion Systems
A less commonly used thermal oxidizer technology is a thermal recuperative oxidizer. Thermal recuperative oxidizers have a primary and/or secondary heat exchanger within the system. A primary heat exchanger preheats the incoming dirty air by recuperating heat from the exiting clean air. This is done by a shell and tube heat exchanger or a plate-type exchanger. As the incoming air passes on one side of the metal tube or plate, hot clean air from the combustion chamber passes on the other side of the tube or plate and heat is transferred to the incoming air through the process of conduction using the metal as the medium of heat transfer. In a secondary heat exchanger, the same concept applies for heat transfer, but the air being heated by the outgoing clean process stream is being returned to another part of the plant – perhaps back to the process oven or furnace.
And Commonly used if the large volumes of exhaust gas from the debinding process in air must be cleaned and/or if there is a risk that the exhaust gases might damage the catalyst. Thermal afterburning is also used for debinding applications under non-flammable or flammable protective or reaction gases.