To keep VOC levels to a minimum and to satisfy EPA requirements, many operations rely on RTOs. This equipment scrubs the air clean before it is discharged into the atmosphere. Essentially, RTOs sit at the exit point for air streams leading away from the factory. The polluted air is vented into these units for 1-3 seconds. The RTO raises the process stream temperature to between 1450 and 1550 degrees Fahrenheit.
However, the oxidation of the air stream does not eliminate particulate and can actually create it. Much of the particulate matter remains within the combustion chamber and throughout the media bed internal to the system. Some process streams can create silica, a sandy residue that settles on the ceramic surface within the RTO. As this residue builds up, it reduces the efficiency of the Thermal Oxidizer. This reduction is caused by reduced airflow, air channeling, increased fuel usage, and increased energy consumption. Another cause is negatively impacting valve seals, which negatively impacts their ability to close, thus reducing flow damper performance.
Routine cleaning of your RTO helps eliminate the build-up of compounds. Proper cleaning requires careful monitoring of the chamber temperature and assessing the presence of contaminants and their concentration. This cleaning also requires determining the proper degree of temperature and the required time for the cleaning agents.
Regenerative Thermal Oxidizer (RTO) Media Cleaning Methods
There are several ways to clean the media within your RTO. These methods include an oxidizer bake out and wash down. It is best to speak to professionals to determine which method is best for your RTO depending on the type of media you are using.
Particulates build up on the cold surfaces located at the bottom of the RTO, which decreases operational efficiency. In order to remove this build up, some units must be off line with the process stream before a volatilization of this material may take place. This cleaning process is referred to as a “bake out.”
When a bake out is started, the flow within the diverter valves remains in a constant position until the temperature of the air exhaust reaches temperatures up to 850 degrees Fahrenheit. When it hits this point, the material will volatilize in the same way that a self-cleaning oven removes grease and grime. As the first outlet bed reaches temperatures up to 850 degrees Fahrenheit, it remains steady until the second bed is heated to the same temperature. This process continues until the entire RTO has been cleaned out.
With a wash down, the media is washed in place with large quantities of low pressure water and chemical solvents that remove the organic material. This method of cleaning does not damage the media. However, wash downs do require extra time after the process. The media needs to dry before being placed back online with the process stream for use of the RTO.
Benefits of Regenerative Thermal Oxidizer (RTO) Cleaning
Cleaning the media within an RTO results in reduced energy consumption, restored pressure drop, increased airflow, and extended lifespan of the media itself. The reduced gas consumption and enhanced lifespan of the media can have a significant impact on a business’ bottom line. Moreover, cleaning the media in an RTO can make it easier to stay within EPA emissions requirements without adversely impacting your operations.