ABSTRACT
The 1990 Clean Air Act Amendments directed the Environmental Protection Agency to establish Maximum Achievable Control Standards (MACT) for major sources of hazardous air pollutants (HAP). Regenerative thermal oxidizers (RTO) are especially suited to applications with low Volatile Organic Compound concentrations but high waste stream flow rates. This is due to their high thermal energy recovery, often as high as 97%. A new type of RTO emerged in the late 1990s. This concept uses a single chamber of heat sink material. A rotating, indexing, waste stream flow diverter sequentially directs the waste stream into and out of specific segments of the chamber during a cycle. The temperatures of the combustion gases entering the stack vary over the period of the cycle. The thermal energy recovery is a direct function of the cycle duration. Usually, cycles are reversed, based on a timer.
