Optimizing RTO Operation Using a Mathematical Model, 1999 Environmental Conference Proceedings

Ken Hiltgen

BE&K/Terranext

Henry McLaurine, Jeff Hanna & Wayne Hardy

Temple-Inland Forest Products Corporation

Regenerative Thermal Oxidizers (RTO’s) are beginning to be used extensively to control emissions in the wood products industry as well as in some pulp and paper applications. RTO’s are not new devices but their application in the wood products industry is new. The major challenge in applying RTO’s in the wood products industry is the simultaneous control of both VOC’s and particulate. RTO’s are packed beds, which adsorb heat and release it again to incoming air when the flow in the bed is reversed. In this manner, heat is conserved and the cost of incineration is greatly reduced by conserving the fuel needed to bring the entire air stream up to incineration temperature. In some applications particulates build up on the face of the bed which causes plugging of the bed thereby increasing the pressure drop across the bed. This requires the bed to be shutdown so it can be baked out before it can be put back on line. Baking out brings the entire bed up to a high temperature (typically 900 degrees F) and requires an outage time, which could interfere with the plant’s production schedule. A mathematical model is developed which calculates bed temperatures throughout the bed during operation. Once calibrated this finite difference model can be used to develop an operation cycle, which can minimize the number of times a bake out is required. The model can also be utilized to study the operation and minimize the amount of fuel usage.