Two-bed regenerative thermal oxidizer with trap for volatile organic

Abstract

A regenerative thermal oxidizer system is useful for treating a waste gas stream that contains volatile organic compounds. Two regenerators each contain heat exchange material that is arranged within the regenerators to recover heat generated by the oxidation of the volatile organic compounds. A first regenerator is in heating service and is used to preheat the waste gas stream before it enters an oxidation chamber where the volatile organic compounds are oxidized. From the oxidation chamber, the waste gas stream enters a second regenerator in cooling service where a portion of the heat generated by the oxidation reactions is recovered. When it is necessary to reverse the flow of waste gas through the regenerative thermal oxidizer, a trap for adsorbing volatile organic compounds is engaged. The trap is useful for capturing any volatile organic compounds contained in the untreated gas in the heating regenerator that would otherwise be released to atmosphere when the heating regenerator is switched into cooling service. During normal operation when the trap is not needed, the adsorbed volatile organic compounds can be desorbed by passing a stream of hot gas through the trap. This hot gas stream is preferably recycled back to combine with the waste gas stream for treatment in the regenerative thermal oxidizer.