Comparison: Regenerative Thermal Oxidizers (RTOs) & Regenerative Catalytic Oxidizers (RCOs)

RTO & RCO Differences

The basics: an RCO = RTO + a catalyst

While a regenerative catalytic oxidizer uses a catalyst to achieve control over combustion of VOCs and HAPs at a lower temperature, an RTO incorporates a heat recovery system to remove pollutants from an industrial exhaust stream at a higher temperature.

Regenerative Thermal Oxidizers (RTOs):

• Purpose: RTOs are designed to destroy VOCs and HAPs in industrial exhaust streams by oxidizing them at high temperatures. They are highly efficient in terms of thermal heat recovery, making them suitable for applications with high air flow and low VOC concentrations.
• Operation: RTOs operate at temperatures typically between 1500°F and 1600°F. They use ceramic media beds to capture and release heat, achieving thermal efficiencies of up to 95-97%.

Learn More: See How RTOs work.

Regenerative Catalytic Oxidizers (RCOs):

• Purpose: RCOs also aim to destroy VOCs and HAPs but do so at lower temperatures by using a catalyst. This makes them more energy-efficient and suitable for applications with lower VOC concentrations.
• Operation: RCOs operate at temperatures between 750°F and 850°F. They also utilize ceramic media beds but integrate catalyst in the beds to achieve similar thermal efficiencies to RTOs but with much lower fuel consumption. ‍

Learn More: See How RCOs work.

Energy Efficiency and Operating Costs

The addition of a catalyst reduces the need for higher temperatures to achieve the same destructive efficiency in an RCO. This can make things easier on the system when compared to an RTO and lowers energy usage.

RTOs:

• Energy Efficiency: RTOs achieve high thermal efficiency (up to 95%) by capturing and reusing heat from the exhaust stream. This reduces the need for additional fuel.
• Operating Costs: While RTOs are fuel-efficient, they require regular maintenance due to the high operating temperatures and moving parts.

RCOs:

• Energy Efficiency: RCOs are even more energy-efficient than RTOs, because they are able to achieve VOC destruction at lower temperatures than standard RTOs While they also have a thermal efficiencies of up to 95%, the lower operating temperatures require significantly lower fuel demand for the same airflow.
• Operating Costs: RCOs have lower operating costs due to significantly reduced fuel & slightly lower electric consumption.

Applications and Use Cases

High air flow applications with low VOC concentrations are the best conditions for using an RTO, while RCOs do best when the chemical makeup of the emissions is consistent and there are low to medium amounts of VOC concentrations.

RTOs:

• Applications: Ideal for industrial processes with high air flow and low VOC concentrations. Very capable of handling most VOC/HAPs with limited particulate.
• Examples: Commonly used in a wide variety of industries like food packaging, surface coating, web coating, gel coating, ethanol production, and wood products.

RCOs:

• Applications: Ideal for processes with well-known, consistent emission compositions with low to medium VOC concentrations. Poisons such as hexanes or masking agents such as silicone & phosphorus in the airstream may preclude applying an RCO.
• Examples: Often used in applications such as chemical, pharmaceutical, wood products (OSB/MDF), and food products.

Maintenance and Reliability

Both units require consistent preventative maintenance for optimal operation, and both are reliable as long as they are well-maintained. The catalyst in an RCO may need to be replaced - at a relatively high cost as they're made from precious metals - if it becomes poisoned by hexanes or other chemicals.

RTOs:

• Maintenance: RTOs require regular inspections and maintenance but have few moving parts: fans, dampers, valves, and burner(s).
• Reliability: Exceptionally reliable with few moving parts. High temperature operation requires frequent inspections for hot spots. Flow direction switching valves (poppets or rotary; pneumatic or electric) are proven performers, but can be challenging in some OEM RTO designs.

RCOs:

• Maintenance: RCOs require similar maintenance to the RTO, with the added need of inspecting and testing the catalyst.
• Reliability: Exceptionally reliable like the RTO but with less risk for hot spots due to the lower operating temperature. Catalyst degradation is a risk and can be an expensive replacement item if it becomes poisoned. Proper review of the process emissions prior to application of an RCO will mitigate this concern.

Converting an RTO to an RCO with Kono Kogs

Can an existing RTO be converted to an RCO? Yes, and usually quite easily. Partnering with Kono Kogs ensures your RTO to RCO conversion goes smoothly and you get a high-functioning regenerative catalytic oxidizer ideal for meeting your application's needs. Here are the basics of the process: 

1. Initial Assessment: Conduct a thorough assessment of your existing RTO system to determine its compatibility with RCO conversion.
2. Catalyst Selection: Choose the appropriate catalyst for your specific application. Catalysts enable chemical reactions at lower temperatures, reducing fuel consumption.
3. System Modification: Modify the existing RTO system to incorporate the catalyst. This may involve adding catalyst beds and adjusting the combustion chamber setpoints, but is relatively simple.
4. Control System Upgrades: Improve & reprogram control settings to manage the new operating parameters and ensure optimal performance.
5. Training and Maintenance: Provide training for operators on the new system and establish a maintenance schedule to ensure long-term reliability.

Contact our team of engineers to get started on a RTO to RCO conversion, or feel free to reach out with any questions about the differences between an RCO and an RTO.