Metal Finishing Guide Book


Issue link:

Contents of this Issue


Page 662 of 843

However, 80% combined system destruction efficiencies have been allowed for plastic parts spray booths employing a carbon adsorber in series with a thermal oxidizer. At least one permitting agency requires a minimum VOC control efficiency for major sources and others allow it as an alternative to laborious record keeping required to demonstrate compliance with individual coating emission limits. • Ohio Administrative Code (OAC) 3745-21-07 (G) Operations Using Liquid Organic Material requires discharge of organic materials (i.e. VOC) be reduced by at least 85% from applying, evaporating or drying any photochemically reactive material and any liquid organic material that is baked, heat-cured or heat polymerized. • Section 215.205 22 Illinois Regulation 11427 allows operators of coating lines alternative emission limitations to individual coating emission limits for emissions controlled by an afterburner (thermal oxidizer): 81% (75% for can coating) reduction in the overall emissions of volatile organic material from the coating line, and Oxidation to carbon dioxide and water of 90% of nonmethane volatile organic material (measured as total combustible carbon) which enters the afterburner. • Under South Coast Air Quality Management District (SCAQMD) of California (Los Angeles) Rules 1107 Coating of Metal Parts & Products and 1145 Plastic, Rubber and Glass Coating, lines may comply with these regulations using pollution control equipment provided VOC emissions are reduced as follows: • The control device shall reduce VOC emissions from an emission collection system by at least 95% by weight or the output of the air pollution control device is 50 PPM by volume calculated as carbon with no dilution. • The owner/operator demonstrates that the system collects at least 90% by weight of the emissions generated by the sources of the emissions. Other examples of minimum required or allowable VOC and HAP collection and destruction efficiencies can be found in various federal, state, and local regulations. In many cases the most advantageous type of oxidizer can be selected based on the following general guidelines. In other cases two or more oxidizer types may be practical and a detailed economic analysis based upon your specific costs of fuel and electricity will be required to determine the best selection. Recuperative Oxidizers A recuperative oxidizer is a direct-fired unit that employs integral primary heat recovery. To minimize the energy consumption of the oxidizer, the hot air exiting the combustion chamber is passed over an air-to-air heat exchanger. The heat recovered is used to preheat the incoming pollutant laden air. The primary heat exchangers are usually supplied as either a plate-type or a shell and tube type heat exchanger. These heat exchangers can be designed for various heat transfer efficiencies, but the nominal maximum is 70%. Thus by the addition of a heat exchanger, the net heat load on the burner can be reduced by up to 70% of that 651

Articles in this issue

view archives of Metal Finishing Guide Book - 2013