Putting the heat on VOCs
A tried-and-true technology for VOC control is oxidation, either catalytic or thermal. Oxidation units can destroy nearly 75 percent of the VOC and toxic emissions targeted by the Clean Air Act Amendments (CAAA) of 1990. In fact, the Hazardous Organic NESHAP (HON) rule finalized last year for synthetic chemical processors specified combustion devices as a technology of choice for treating fumes from process vents or transfer operations. In 1995 alone, according to recent forecasts, U.S. industry will spend more than $200 million on fume incinerators, which represents about 40 percent of all VOC control equipment purchases. The decades-old technology operates on a simple premise: Sufficiently heating a VOC consisting of carbon and hydrogen, in the presence of oxygen, will reduce the VOC to harmless carbon dioxide and water. As with any incineration process, the critical elements of successful thermal treatment are time, temperature and turbulence. This means the waste gas must be kept at incineration temperature for an adequate amount of time, generally 0.75 to 1 second. To destroy 98 percent of VOCs, a thermal process will heat VOCs to about 1500 F; a catalytic system will heat the pollutants to around 700 F. Factors influencing the temperature of an individual application include the chemical makeup of the VOC and oxygen availability. Finally, turbulence ensures adequate contact between process air and VOCS, and may be achieved in a variety of ways, such as through the use of fluidized catalyst beds.
- OSTI ID:
- 116291
- Journal Information:
- Pollution Engineering, Journal Name: Pollution Engineering Journal Issue: 9 Vol. 27; ISSN PLENBW; ISSN 0032-3640
- Country of Publication:
- United States
- Language:
- English
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