Catalytic Oxidizers v/s Thermal Oxidizers

Although their continues to be a rising demand for lowering emissions and adhering to stringent

environmental emission rules, it’s been almost 25 years since oxidizers have been used for the purpose

of industrial exhaust treatment.

VOCs and HAPs are the main products of concern in industrial process exhausts. The ideal method of

treatment is oxidization of these streams. While thermal oxidation still remains the age-old grand-dad of

this processing; due to increasing energy prices, the use of catalysts has been supplemented to conserve

energy and production costs.

While thermal units oxidize the exhaust stream at temperatures equal to or above 1500oF, catalytic

systems oxidize around 600-700oF, which implies better fuel efficiencies. However, this is just one of the

differences to note in thermal vs. catalytic oxidizers.

While both units have similar construction, thermal oxidizers can cater to industries with heavier inflows

of exhaust. Industries like ceramics and metals use thermal oxidizers; so that they can directly address

their large volumes of low VOC/HAP concentrated exhausts. Thermal oxidizers are used with higher

temperatures and longer activity periods, or long hours of production, than are catalytic oxidizers.

Thermal units can be used in more industries than their catalytic counterparts, since the catalyst beds

are sensitive to certain emissions which involve chlorinated compounds, sulfur, phosphorus or heavy

basic metals such as lead, mercury, arsenic, antimony, zinc, copper, tin, iron, nickel and chrome (all

being known catalyst poisons/deactivators). If any of these contaminants are present in the air stream, a

catalytic oxidizer would not be the best control device selection.

Catalytic units come into play where the flow of exhaust is relatively slow, allowing time towards

exposure and recycling, without any ancillary blowers; and wherein, the concentration of VOCs/HAPs is

pretty intense. Catalysts are placed in these oxidizers, to destroy pollutants. The oxidization of the

polluted gas occurs via a chemical reaction with the catalyst, thereby saving fuel. Moreover, catalytic

units have greater life longevity, but are larger initial investments due to their customized catalytic beds.

All in all, if the process allows for a catalyst, this unit will save the manufacture money in terms of the

initial investment, fuel costs and production costs.

For more information, please visit http://www.stelterbrinck.com/thermoxi.htm or call Stelter & Brinck

at 513-367-9300.

Keywords: catalytic oxidizer, thermal oxidizer, stelter & brinck, catalyst, oxidization, pollution control

equipment, voc abatement, pollution destruction, low nox, low co