burners for a variety of oven applications are also available. Generally ovens
operate at much lower temperatures than furnaces. However, process ovens often
operate in large manufacturing facilities in nonattainment areas and, thus, require
burner retrofits. These burners utilize various methods of mixing the air and
the fuel and also employ staged combustion techniques developed specifically for
these applications. Typical reductions of NOx in the 80% range can be obtained.
Specific information on various low NOx burners for ovens can best be obtained
on the vendor's website.
have been developed for many industries that emit organic hazardous air pollutants
(HAPs) from ovens. These standards require the removal or treatment of the HAPs
that are emitted from ovens used for metal coatings, various types of paint baking,
and other emissions in the general category of "evaporative losses."
Natural gas technologies are often used to destroy these HAPs. Examples include
direct thermal oxidizers, catalytic thermal oxidizers and carbon absorption systems.
Originally developed to destroy VOC emissions from process sources, these are
well-established technologies. Other available options include reformulation to
use coatings and raw materials that do not produce HAPs. By reformulating solvent
based coatings to powder coatings, low-emission gas infrared technologies can
replace conventional ovens to meet emission standards. Each of the following technologies
uses natural gas to reduce organic HAPs and to comply with MACT standards for
emissions from ovens. A brief description is provided.
- Use heat to
burn and destroy organic pollutants (VOCs, Air Toxics and Odors).
determine time and temperature requirements for each pollutants' destruction.
- Direct, recuperative,
regenerative and catalytic types available.
thermal oxidizers use large amounts of fuel, low capital cost.
thermal oxidizers preheat (to increase the temperature) the incoming flow of air
and HAPs. Limited by air-to-air heat exchange economics.
thermal oxidizers use regenerative heat exchange with large canisters that cycle
to preheat the incoming flow and minimize fuel consumption. Regenerative thermal
oxidizers conserve fuel at low rates with the highest capital cost.
thermal oxidizers use a catalyst bed that results in lower required temperatures
for destruction of HAPs. Catalytic oxidizers also consume lowervolumes of fuel,
but catalyst issues can include cost, possible contamination and disposal.
and Catalytic Oxidizers
- Based on selective
adsorption of HAPs, uses activated carbon or other material to adsorb HAP. These
systems utilize steam to regenerate the adsorption beds.
- Can be used
to concentrate HAPs before incineration.
on manufacturers of these technologies is included in the vendor listing.