Mistakes Made On Regenerative Thermal Oxidizer Pollution Control Equipment
Posted: Tuesday, October 12, 2010
by Scott Manes
American Environmental Fabrication & Supply,LLC
1. Wrong material for the waste gas process application. Choosing materials that are right for the application will promote equipment life and regenerative thermal oxidizer dependability.
A. Skin or Shell Material Selection (Metal Type i.e. Carbon, Stainless Steel, Inconel, Thickness 3/8")
B. Valve Selection (Poppet Valves vs. Butterfly) Poppet valves are not as reliable, but cost effective.
D. Paint (High Temperature vs. Hot Dipped Galvanized) Painting will be required to some extent each year.
E. High Quality Solenoids, Compressors, etc. This is the heart of the valve system, buy high quality.
2. Characterization of the Plant Process Stream.
A. Misrepresentation or making an educated guess of the density of plant waste-off gases. It is extremely important to know the amount of VOC's, HAP's or other gases that the regenerative thermal oxidizer system will be processing. This is especially important when the off gases contain halogens or H2S. Specify the amount lbs. per hour or ppmv this will allow for the proper design of the thermal oxidizer abatement equipment.
3. Plant's required vacuum pressure or the amount of VOC's.
A. This is a very common occurrence in the industry. Either the OEM builds a system to fit a budget as part of the available capitol or the plant tries to get by with less. Either way, at start up the environmental equipment one finds themselves with a real problem. They can't process the waste-off gas amount, vacuum pressure is inadequate or the regenerative thermal oxidizer (RTO) unit runs too hot and is continually shutting down.
4. Sizing the Regenerative Thermal Oxidizer Heat Recovery System.
A. A common problem is when equipment companies size the heat recovery system for normal plant VOC volume and not for high loading or spiking conditions that may exist in the plant from time to time. Often the designer will manufacture a thermal oxidizer system for the average VOC loading condition, only to find that the plant has frequent spike conditions. The regenerative thermal oxidizer system should be able to handle these frequent spikes. These spikes can be addressed by use of a hot air by pass system which operates during these spike phases. Afterwards when normal VOC conditions return the system will again be running at maximum heat recovery efficiency. When spikes in the process flow occur your heat recovery efficiency will not be an issue.
5. Incorrect Heat Recovery Media or Heat Recovery Media Placement.
A. Incorrect media sizing or type can result in system fouling (plugging) or loss in thermal efficiency. Improper media placement can result in inefficiencies by means of the process stream channeling. Proper media size and media protection can protect the media material and give the system better thermal efficiency. Often air pollution manufactures may specify ceramic media that is in stock or readily available and quality is inferior.
6. Improper Plant Particulate Filtration.
A. Poor or lacking maintenance of upstream particulate removal. This is very common issue when the plant maintenance department fails to maintain proper filtration of the plant process gases going to the regenerative thermal oxidizer. Poor filtration or lack of equipment in many off gas processes will result in early media replacement or continual media cleaning.
7. Compliance Testing.
A. Testing the regenerative thermal oxidizer equipment above the permit requirement. Often companies wish to run the system at higher destruction. This is great; however testing above the permit level can cause a new set of problems. You may be required to operate the regenerative thermal oxidizer equipment on an established baseline. After a period of time the thermal oxidizer may be running in compliance with the original permit, but fails to be in the higher baseline due to aging of valve seals or particulate within the media. At this point you may be out of the established baseline compliance. For more information about regenerative thermal oxidizers visit: American Environmental Fabrication & Supply or call us at +1 918 708-1253 Ext. 4001
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