Corrosion of Ceramic Bed in Regenerating Thermal Oxidizers

Regenerating thermal oxidizers (RTO) are widely used across the US to destroy fugitive emissions from wood-processing plants and other industries. The use of ceramic beds in order to recover significant portions of the heat used for oxidizing the exhaust gas-natural gas mix allows achieving up to 95 % thermal efficiency.
Dryers of wood chips in a typical wood processing plant are usually heated by burning wood-based biomass material. Some of the ash from the combustion is transported through the dryer and capture devices making its way into the RTO. In addition, small wood particles entrained in the exhaust gas escape capture and end up being burned inside the ceramic bed contributing to the total ash loading of the RTO. This ash typically contains Sodium and Potassium salts, which when exposed to high temperatures of the combustion chamber, react with the ceramic materials contributing to their deterioration within a relatively short service period of several years. The paper discusses factors responsible for the destruction of ceramic bed and in particular, the effect of temperature of combustion. It describes methods of semi-quantitative evaluation of the extent of destruction, which we use to determine the time for changing the media