Therser UK Blog

RTO: Regenerative Thermal Oxidisers Explained

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A Regenerative Thermal Oxidiser (RTO) is an effective pollution controlling incinerator used in a number of manufacturing industries. An RTO burns off airborne pollutants in furnace/kiln exhaust so that they do not get into the air and turn into toxic soot.

A Regenerative Thermal Oxidiser uses a ceramic heat transfer bed and multiple heat chambers to recover as much energy as possible after the oxidation process. In this they differ from afterburners and other incinerators.  An efficient RTO will be able to recover up to 90-95% of the energy, and will often be able to operate without external power.

RTOs are widely used for treating industrial process gases containing a wide variety of VOCs and other air toxins.  They not only provide a viable pollution control mechanism in a world of increasingly stringent environmental and legal emission requirements but also yield a more fuel-efficient technology in a world of ever-increasing fuel costs.

Common industrial processes include:

  • Chemical processing
  • Flexographic printing
  • FRP manufacturing
  • Heat-set printing
  • Paint & coatings manufacturing
  • Surface coating
  • Wood finishing & manufacturing
  • Many others…


  • High destruction efficiency
  • System flexibility
  • High volumetric turn-down capacity
  • Up to 95% thermal energy recovery
  • Structured thermal energy recovery media
  • Lower destruction temperature


  • Complies with UK and EU clean air legislation
  • Addresses wide range of process conditions
  • Easily controls multiple sources of VOC emissions
  • Self-sustains at Lower Explosive Limits (LEL) as low as 3%
  • Lower auxiliary fuel consumption
CLICK HERE to download 'Controlling Air Pollution & Emissions In Manufacturing'

How does at RTO differ from other incinerators?

Recuperative Thermal Oxidisers

Regenerative thermal oxidisers differ from direct flame oxidisers in that they employ a series of ceramic heat regeneration beds that enable them to transfer much of the heat energy released during the oxidation reaction to the inlet process air stream.  These beds serve as highly efficient heat exchangers, recycling through conduction heat that would otherwise be lost to the atmosphere in direct flame oxidiser units.

Direct Flame Oxidisers/Incinerators

Regenerative Thermal oxidisers are frequently confused with Recuperative Thermal Oxidisers. These two incinerators share similar goals, although they differ in design.  A recuperative thermal oxidiser uses a heat plate, tube or shell to heat intake air using the thermal energy from the oxidation process. This form of oxidiser is usually less effective than a regenerative oxidiser because they only recover 50%-75% of the energy.

Making The Right Choice

When it comes to deciding what unit will work best within your facility, it is important to remember that the higher the destruction efficiency, the less pollutants that you are going to release into the air. You will also need to ensure that there is proper ventilation around the unit to ensure that it is going to work properly and efficiently for its intended use.

To find out more about air pollution control, download our free eBook: Controlling Air Pollution & Emissions In Manufacturing With After Burners & RTOs. The guide explains all the different types of industrial incinerator, plus the relevant clean air legislation for common pollutants. Get your copy today by clicking here.

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