TO and RTO are both abbreviations used in the context of air pollution control equipment.

Here's the difference between the two:
 
Thermal Oxidizer (TO): A thermal oxidizer, also known as a combustion chamber or afterburner, is a device used to treat and destroy volatile organic compounds (VOCs) and hazardous air pollutants (HAPs) emitted from industrial processes.
 
It uses high temperatures (typically between 760°C to 1093°C or 1,400°F to 2,000°F) to oxidize the pollutants into carbon dioxide (CO2) and water vapor.
Thermal oxidizers are often used in applications where the VOC concentration is relatively low.
 
Regenerative Thermal Oxidizer (RTO): A regenerative thermal oxidizer is an advanced type of thermal oxidizer that offers higher energy efficiency.
 
It also uses high temperatures to oxidize VOCs and HAPs, but it incorporates a heat recovery system to minimize fuel consumption. RTOs use ceramic heat exchange media to capture and store heat generated during the oxidation process.
 
This stored heat is then used to preheat the incoming pollutant-laden air, reducing the energy requirements for maintaining the high oxidation temperatures.
 
RTOs are typically used in applications with low concentrations of volatile organic compounds.
 
In summary, while both TO and RTO are thermal oxidation technologies used for air pollution control, RTOs are a more advanced and energy-efficient version of thermal oxidizers, utilizing a heat recovery system to minimize fuel consumption.