Introduction:
Thermal Oxidisation Packages are typically used to destroy Hazardous Air Pollutants (HAPs) and Volatile Organic Compounds (VOCs) from industrial air streams. These pollutants are generally hyrdocarbon based and when destroyed via thermal combustion they are chemically changed to form CO2 and H2O.
Regenerative Thermal Oxidizer (RTO):
World’s most widely accepted air pollution control technology across the industry is a Regenerative Thermal Oxidizer, commonly referred to as a RTO. They are very versatile and extremely efficient – energy recovery efficiency can reach 95%. This is achieved through the storage of heat by dense ceramic stoneware. Regenerative Thermal Oxidizers are ideal in low VOC concentrations with larger process requirements. Systems can be used during long continuous 24 hour operations.
AES Regenerative Thermal Oxidizers have the capabitlity of 99+% Volatile Organic Compound (VOC) destruction efficiencies. The ceramic heat exchanger(s) are designed for thermal efficiencies as high as 97+%. Regenerative Thermal Oxidizers are designed with multiple hot gas bypass systems, bake-out cycles, re-circulation heat exchangers and O2 monitoring to reduce carbon monoxide and nitrous oxide. Many environmental agencies are requiring continuous O2 monitoing for the control of these secondary gases. Higher VOC streams allow the RTO to operate at reduced or zero fuel usage, which makes these systems ideal for certain plant operations.
Concept of Regenerative Thermal Oxidizer (RTO):
The basic design concept of thermal oxidization is to promote a chemical reaction of the air pollutant with oxygen at elevated temperatures. This reaction destroys the pollutant in the air stream by converting it to CO2, H2O and heat. The rate of reaction is controlled by three-(3) interdependent and critical factors; time, temperature and turbulence.
In operation, the process exhaust fumes are forced into the RTO inlet manifold (with a high pressure supply fan) and directed into one of the energy recovery canisters by use of inlet (switch) valves. The pollutant laden air passes from the valve assembly vertically upward through the first of the heat exchanger canisters where it adsorbs heat from the ceramic media (thus eventually cooling the media). This preheated air then enters the combustion chamber (typically at a temperature very close to that required for oxidation), is thoroughly mixed for temperature uniformity (turbulence) and held in the combustion chamber at the elevated set-point temperature (temperature) for a residence time of ~0.5 seconds (time). Air pollutant destruction takes place within the combustion chamber where auxiliary fuel is introduced if necessary.
After passing through the combustion chamber, the clean (hot) air is routed vertically downward through a second energy recovery canister where the heat generated during thermal oxidation is adsorbed by the ceramic media (thus preheating the media for the next cycle). The clean (cooled) air is routed to atmosphere through outlet (switch) valves, the exhaust manifold and ultimately through the exhaust stack. To maximize the heat exchange, the switching valves alternate the airflow path between canisters to continuously regenerate the heat stored within the ceramic media. Thermal Energy Efficiencies Ratio (TER) range from 85% to 97%. To maintain low external shell temperatures and minimize radiant heat loss, the combustion chamber is insulated with long-life ceramic fiber modules. The external shell is typically fabricated of carbon steel. Air pollutant destruction efficiencies of 99% can typically be guaranteed.
Important Features & Advantages:
1) Guaranteed 98-99 % VOC destruction efficiency – Compliance to the global emission regulatory.
2) Up to 95% heat transfer efficiency – Lowest operating cost and lower CO2 emissions
3) Completely modular – quick, 3-day installation.
4) Exclusive, light weight heat recovery media & Control – Lowest pressure drop, highest thermal efficiency, easy to operate & control
