Regenerative Thermal Oxidizer

During regenerative thermal oxidizer (RTO) the exhaust air is heated up to 820 °C. The VOC changes to CO2 and H2O. During this exothermal reaction heat is released. This heat reduces the amount of energy for the pre heating of the air. The regenerative afterburning is typically equipped with multiple chambers. Every chamber has a high efficient heat accumulator made from ceramic. The exhaust air purification from VOC via RTO works in the following parallel / inline steps:

  • Step 1: After heating

    When the chamber/heat accumulator is heated up the VOC containing air is led in by a throttle system. The air which flows through the heat accumulator is heated up until it enters the burning chamber.

  • Step 2: VOC oxidizing in the burning chamber

    In the burning chamber the exhaust air containing VOCs are oxidized at temperature about 850 °C to CO2 and H2O. The required energy comes from the exothermal reaction of oxidizing solvents. In case the exothermal energy is too low it is required to add additional fuels. In case the exothermal energy of the solvents is higher than for the autothermal operation (operation without additional fuels) of the RTO this energy can be used by separation of hot gas for heat recovery for generation of steam, heating of water, air or thermo oil.

  • Step 3: Exhaust air feds the heat accumulator

    The hot and purified air flows after the burning chamber through a second chamber with ceramic heat accumulator where the heat transfer takes place. After that the purified air leaves the RTO chamber cooled down through the chimney.

  • Step 4: Air purge

    The exhaust air containing the VOC is led by a throttle system (similar to step 1) into the second chamber with heated accumulator. At the same time the first chamber with heat accumulator is not flown through with further contaminated air. Instead it is flushed in the opposite direction and the remaining VOC are removed to prevent that they enter the purified air. The flushing air which contains some VOC is mixed with the contaminated air to be cleaned again.

During the course of exhaust air cleaning the chambers are controlled in cycles by a throttle system. That means one chamber is used for heating the exhaust air, one chamber is heated up by the purified exhaust air and the third chamber is flushed with clean air.


  • Robust design, reliable operation, long lifetime
  • High cleaning quality at low energy consumption
  • Further use of heat is possible

Applications and limitations:

  • Recommended for volumes with high VOC concentration: 5,000 – 300,000 m³/h, < 10,000 mg/m³
  • Unsuitable for SiO2

Contact us without obligation with your key data for the exhaust air to be cleaned. We would be happy to plan and implement your exhaust air purification system using the regenerative post-combustion process.