Recuperative thermal oxidizer

What is the Difference Between a Regenerative Thermal Oxidizer and a Recuperative Thermal Oxidizer?

While both are a type of Thermal Oxidizer, the difference between a Regenerative Thermal Oxidizer (RTO) and Recuperative Thermal Oxidizer is how these machines use heat recovery during the oxidation process. RTOs combine hot exhaust gas with cool gas and passes this mixture through several heat exchanger chambers, typically made out of ceramic. A Recuperative Oxidizer passes exhaust through air-to-air heat exchangers that heat cool gas.

What is a Regenerative Thermal Oxidizer?

A Regenerative Thermal Oxidizer (often referred to as RTO) destroys pollutants like Hazardous Air Pollutants (HAPs), Volatile Organic Compounds (VOCs), and odorous emissions that are often discharged during industrial processes.

RTOs typically operate at higher temperatures than Recuperative Thermal Oxidizers and have a much higher heat recovery efficiency than its Recuperative counterpart. By storing heat produced during the cooling process for other systems, RTOs can be the more efficient option when choosing between different types of Thermal Oxidizer.

What is a Recuperative Thermal Oxidizer?

Recuperative Thermal Oxidizers are less common than RTOs. These machines run cooler than other oxidizer types, and heave a lower heat recovery efficiency than RTOs and other oxidizer types.

The benefit of using a Recuperative Thermal Oxidizer is in its VOC destruction ability. Recuperative Thermal Oxidizers have a VOC destruction efficiency of 99.99%, while an RTO that can only produce a 99% destruction efficiency in the very best and optimal conditions.

Why Is A Heat Recovery System Important?

By adding a heat recovery system to the oxidation process, the amount of natural gas needed to complete the process is greatly reduced. This can mean energy and cost savings during the VOC oxidation process. Recuperative Thermal Oxidizers use two types of heat recovery in their processes.

First, primary heat recovery occurs when the VOC-filled exhaust is passed through a heat exchanger. This recovers (i.e., recuperates) the heat created from the exhaust and reuses it to pre-heat the air that comes in through the combustion chamber. This means that the amount of heating needed for the process is reduced, as well as the gas needed to reach safe oxidation temperatures.

Secondary heat recovery is when the waste heat from oxidation is reused to support secondary processes, like heating for an industrial oven or other industrial processes.

Recuperative Thermal Oxidizer or Regenerative Thermal Oxidizer – Which is Better?

Regenerative Thermal Oxidizers are today’s most common oxidizer technology of choice, because they achieve the highest VOC destruction with the lowest operating cost. They also maintain the highest reliability when compared to other thermal oxidizer technologies. All Regenerative Thermal Oxidizer technologies achieve VOC destruction by exposing pollutant-containing air to a high temperature, for a set period of time, in a turbulent flow path.  Time, temperature and turbulence- Three T’s– are critical and co-dependent factors that determine oxidizer performance.

Difference Between a Regenerative Thermal Oxidizer and a Recuperative Thermal Oxidizer rto diagram

Regenerative thermal oxidizer systems utilize a special heat recovery method – regeneration- that has proven to be the most cost-effective approach for typical industrial applications.

Considerations When Choosing an RTO

  • Is the RTO optimized for my exhaust airstream?
    • RTO’s typically treat airstreams with a 0-10% Lower Explosive Limit (LEL)
    • RTO systems can handle 25% Lower Explosive Limit (LEL) airstreams
      • Hot gas bypass systems and other features may be needed
  • Is the ceramic media in the RTO optimized for:
    • maximum thermal efficiency
    • lowest pressure drop
    • Ability to handle organic/inorganic particulates
  • Does the RTO main fan utilize a variable frequency drives (VFD)?
    • Important for volume turn-down and idle operation
  • Is the RTO skid mounted with little welding required in the field?
    • Ease of installation will result in lower turnkey cost
  • Does the RTO have telemetry (Ethernet) for remote troubleshooting access?
    • Remote troubleshooting access  can reduce service visit frequency
  • Are visible emissions eliminated by this RTO?
    • A puff capture feature may be required to eliminate visible emissions
  • Is the RTO burner designed to maintain temperature during full flow, no VOC conditions?
  • Would a fuel gas injection system be a wise choice for this application?
    • Fuel injection can provide significant fuel savings
  • Is there a used RTO system available with the features needed?
    • Quality-built used regenerative thermal oxidizer (RTO) systems have a long life, can save 40-60% vs. new units, and offer performance and parts warranties

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