Thermal Oxidizer

Q. Our client has an RTO on its aluminum window frame painting line, and we supplied a total hydrocarbon analyzer to meet compliance. We get a huge spike in the readings when the RTO chambers cycle every four minutes. We can go from 3 to 6 ppm for four min, then spike to 400 to 1,000 ppm for a few seconds. I don’t believe RTOs should work that way and that switching should have little or no effect on efficiency. I think the client’s unburned paint is contaminating our gas analyzer. T.Y.

A. I believe you are right in your assessment of the problem. I’m guessing from your description that by “RTO” you mean regenerative thermal oxidizer and not recuperative thermal oxidizer. Both types of incinerators are used to burn volatile organic compounds in spray booth exhaust air, but this particular type uses heated ceramic discs.

I suspect that the operating temperature of the heated ceramic discs is not high enough, thus causing spikes in your readings. This may be caused by the hot air entering the ceramic disc bed not being up to the specified temperature, which should be at least 1,500ºF.