Regenerative Thermal Oxidizers (RTOs) can regenerate the heat of a large thermal mass and are an effective and fuel efficient option.
Thermal oxidizers destroy toxic particulates in the air and volatile organic compounds often emitted in industrial process exhausts. They typically do this by capturing heat from an outgoing air stream to preheat incoming air. This often has the effect of reducing operating costs.
The two most typical methods of reclaiming heat are regeneration and recuperation. When the heat contained within a large thermal mass is regenerated, a thermal oxidizer employing this method is called a regenerative thermal oxidizer. Recuperation implies more of a direct heat transfer from the outgoing to the incoming air stream. When this method is used, the system is called a recuperative thermal oxidizer.
What happens with a regenerative thermal oxidizer is intriguing. Gas laden with volatile organic contaminants enters a Twin Bed RTO via an inlet manifold. The gas is directed by a flow control valve as it spews into an energy recovery chamber; work that takes place within this chamber is primarily preheating. Heating of the process gas and contaminants continues in a place called the stoneware bed as the gas stream moves toward a combustion chamber. It’s in the combustion chamber where the most exciting part of the entire process occurs: The volatile organic compounds, or VOCs, are oxidized. This oxidation releases a surprising amount of energy into a second stoneware bed. This stoneware bed is in turn heated while the gas, a bit less volatile, is cooled until the outlet gas temperature is only slightly higher than the inlet temperature. The flow control valve switches and alternates stoneware beds so that each is in inlet and outlet mode. Depending upon the amount of VOCs contained in the process gas, the energy released from the combustion can be self-sustaining. At 96% thermal energy recovery, the outlet temperature may be only 74 degrees F. (23 degrees C.) higher than the inlet gas temperature.
Components of a traditional RTO (regenerative thermal oxidizer) include a system fan, motor, burner, heat exchange media, flow control valves, electronic & automatic system controls, temperature recorder, and exhaust stack. The system’s outer skin is typically ceramic and fiver-lined, but comprised primarily of steel.
Derek Lang is with Epcon Industrial, a manufacturer of air pollution control systems, thermal oxidizers, and industrial gas fired ovens. To learn more about thermal oxidizers, catalytic oxidizers, air pollution control systems, industrial ovens at Epconlp.com.
