Determination of supplemental fuel requirement and instantaneous control thereof involving regenerative thermal oxidation

A control system for a regenerative thermal oxidizer in which contaminated air is first passed through a hot heat-exchange bed and into a communicating high temperature oxidation (combustion) chamber, and then through a relatively cool second heat exchange bed. The apparatus includes a number of internally insulated, ceramic filled heat recovery columns topped by an internally insulated combustion chamber. Contaminated air is directed into heat exchange media in one of said columns, and oxidation is completed as the flow passes through the combustion chamber. From the combustion chamber, the now clean air flows through another column containing heat exchange media, thereby storing heat in the media for use in a subsequent inlet cycle when the flow control valves reverse. The resulting clean air is directed via an outlet valve through an outlet manifold and released to atmosphere or is recirculated back to the oxidizer inlet. A combustible fuel such as natural gas is added to the inlet-contaminated air prior to its entry into the hot heat exchange column when the contaminant concentration in the contaminated air falls below a predetermined level. The oxidizer is preferably integrated with a web dryer, such that hot aire from the combustion chamber is supplied to the dryer.