Frequently Asked Questions

Yes, our RTOs are typically skid-mounted and pre-assembled to minimize field welding and on-site labor. This simplifies installation and helps reduce overall turnkey project costs.

Yes, in some cases. Visible emissions or opacity, often seen as puffs during poppet transitions, can occur. However, a puff chamber can significantly reduce or eliminate these visible emissions.

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Feel free to check our RTO Inventory and get in contact with our sales and applications engineers to ensure that the system meets your needs. Quality-built refurbished regenerative thermal oxidizer (RTO) systems offer a long service life, can save you up to 40% compared to new units, and come with performance and parts warranties comparable to those of new systems.

Yes, our oxidizer's controls come standard with remote access, which allows for real-time, remote troubleshooting, which will reduce the need for on-site service visits.

RTOs typically operate at 1500^o – 1600^o Fahrenheit depending upon the VOC characteristics. Thermocouples inside the chamber monitor temperature and adjust gas burner firing as needed. Adequate temperature is essential to ensure VOC destruction efficiency. In most cases a data log of chamber temperature is required for air quality compliance.

Perhaps. The retrofit typically involves catalyst somewhere in the media bed, allowing the unit to operate as Regenerative Catalytic Oxidizer (RCO).The result is reduced operating temperatures and energy savings. However, the conversion may be more complex or not possible if the unit is older, heavily customized, or in poor condition. Please contact KKI for a detailed review of the process.

Yes, we can assist in evaluating your system to identify issues such as leaking valves, heat exchanger problems, poor airflow distribution, or catalyst performance. We provide thorough assessments and turnkey solutions to help you stay operational. For regenerative thermal oxidizers (RTOs), see our blog post about stack test failures for more troubleshooting guidance.

Yes, we can support both turnkey projects and specific needs like ductwork and damper sizing and supply or other fabrication needs. Through our Complete Air Fab division, we offer extensive fabrication capabilities and can provide or install ductwork as part of a full turnkey solution—or handle any portion of the project you prefer. Check out our case studies to see examples of our work.

It depends. Regenerative thermal oxidizers (RTOs), depending on age, may be good candidates for repair, rebuild, or upgrade, which is often more cost-effective than full replacement. Upgrades may include PLC modernization and energy-saving features. Thermal recuperative oxidizers are usually less cost-effective to repair long-term, though minor fixes can extend their life temporarily. Catalytic recuperative oxidizers can be repaired, but costly catalyst replacements may justify system replacement if contamination is frequent. Contact us for an evaluation, and we can provide honest guidance to help you choose the best long-term option.

Yes, the type of ceramic media in an RTO can be optimized for an exhaust airstream. Using the right type of ceramic media can maximize thermal efficiency, minimize pressure drop, and better handle organic and inorganic particulates that may be present. Check out this case study for more information.

Note: Regular preventative maintenance and understanding your airstream's composition are cruical for determining the appropriate timing for media replacement.

In most cases, yes. But proper evaluation is recommended to establish that no potential catalyst poisons or masking agents are present in your airstream.

It depends on your location. Some local and state regulations require low NOx emissions, especially in non-attainment or ozone-sensitive areas. To find out what applies to your facility, contact your local air permitting authority or environmental regulatory agency. If needed, low NOx burners can be retrofitted to your system to meet these requirements.

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Yes, if your process stream contains corrosive compounds or halogenated compounds (like chlorine, bromine, or fluorine), the RTO may require special materials of construction such as high-alloy stainless steels or corrosion-resistant coatings to ensure long-term durability and safe operation.

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Yes, most RTO systems are equipped with a VFD on the main fan. VFDs are important for efficient operation, allowing for volume turn-down, improved energy savings, and idle-mode operation when full airflow isn’t needed.

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RCOs offer greater fuel economy, while recuperative units may be best for high VOC concentration airstreams (or an RTO can be considered). Contact KKI for guidance in choosing the right oxidizer for your application.

Catalyst utilized in a regenerative catalytic oxidizer (RCO) allows chemical reactions to occur at lower temperatures (700-800F) than they occur in a thermal oxidizer (typical 1400-1450F) or an RTO (typical 1600F).

Read more in Comparison: RTOs and RCOs.

We can evaluate your current oxidizer’s capacity alongside the new process requirements to recommend the best upgrade approach. Options may include adding new heat exchanger media, installing a larger fan, or modifying the burner and combustion chamber to meet destruction needs. For some cases, using a VOC concentrator to reduce pollutant levels before the oxidizer can be an effective solution. Please note that existing equipment may not be sufficient, even with changes or upgrades.

Regenerative thermal oxidizers (RTOs) have a heat recovery (efficiency) of 95% typically. This technology has the lowest operating cost of all thermal oxidizer systems – not to mention the longest service life and highest reliability. It’s even possible for an RTO to operate with no auxiliary fuel use whatsoever if process VOC concentration levels are >3-4% lower flammability limit (LFL).

Thermal Oxidizers (TOX) have a heat recovery (efficiency) of 70% typically, but some custom designs will use lower efficiency heat exchangers if VOC concentrations are elevated. This technology has higher operating cost than most oxidizer systems.

Your operating permit will define a time (typically every 5 years), but a wise maintenance practice is to test annually as part of a preventive maintenance inspection.

It depends on numerous factors. See Selecting an Oxidizer for guidance or call us for guidance.

Yes, RTOs can be designed to match your specific exhaust airstream characteristics. They are typically optimized for airstreams with solvent concentrations in the 0–10% Lower Explosive Limit (LEL) range. For higher concentrations up to 25% LEL, additional features such as hot gas bypass systems may be needed to ensure safe and efficient operation.

Provide us your particulate description, or send us a sample. We can recommend a cleaning cycle and procedure, new more plug-resistant media, upstream filtering, and/or regular media change outs. A site visit will be needed to fully evaluate the issue.

A rotary valve is often a better choice than a poppet valve for processes sensitive to pressure pulses, as poppet valves can generate pressure fluctuations that may affect product quality.

We can evaluate your heat exchanger, whether metal recuperative or ceramic regenerative, to see if upgrading to a more efficient type is possible. Adding a catalyst might also help reduce gas usage. In some cases, replacing the oxidizer with a more efficient system is the best option. We can check our inventory for suitable units or design a custom system tailored to your needs.

We can evaluate your system by measuring airflow and emissions at key points to assess its current performance. If it’s not optimized, we’ll recommend improvements such as adjusting system settings or adding capture hoods and enclosures. We can also provide these solutions as part of a new system if needed.

Chemical, pharmaceutical, OSB (oriented strand board) press, particle board dryer, MDF (medium density fiberboard) dryer, plywood, paint spray booths;  and any application under 2% LFL is a good candidate.

TOX with heat exchangers typically have a shorter life span than CATOX systems or RTO systems. This is due to the elevated operating temperatures that the heat exchanger is exposed to. Especially detrimental to the system are repeated on/off cycling that imposes significant thermal stress on the heat exchanger. It is best to apply these systems in applications that run 24/7/365.

Typical applications for catalytic oxidizers can range from ambient to very high process temperatures, mildly corrosive exhaust streams, and particulate free or well filtered airstreams with no catalyst-masking chemicals.

Direct, Regenerative and Recuperative. See Types of Catalytic Oxidizers.

Extensive catalyst application experience allows our engineers to select the best catalyst type, and pair it with an optimized ceramic media mix for long life, and for low fuel and electric use.

We can evaluate the mechanical condition and electrical controls and recommend improvements to resolve reliability problems. Your oxidizer shouldn’t disrupt production. Our service technicians work nationwide and may already be near you. Visit our service page or contact us for assistance.

Using a bake-out feature can help prevent and remove organic compound buildup in the ceramic media, reducing the risk of plugging and maintaining efficient operation. A preheater or recirculatioin loop are also possible mitigation methods.

Hotspots typically result from damaged or missing insulation or compromised metal surfaces that allow heat to escape. KKI has experienced fabricators and insulators who can repair your oxidizer. This may involve replacing damaged metal to provide a secure base for reattaching insulation modules and restoring proper thermal protection.

The term “regenerative” in regenerative thermal oxidizer (RTO) is drawn from the type of ceramic media heat exchanger used in these systems. It is unique in that it captures heat from the exhausting, clean airstream during one cycle and releases the heat to the incoming, dirty airstream in the next cycle. The heat is captured (and released) from beds of ceramic media. The RTO incorporates switching valves to cycle the direction of the airflow through the RTO heat exchanger beds to enable regenerative heat recovery.

Clean process airstreams with high air flow and low VOC content (<10% LFL) are ideal applications. Higher VOC concentrations can be tolerated, as well as organic/inorganic particulates with proper planning and design, and possibly filters. See our case studies for a sample of possible applications.

Applications with fairly clean process airstreams with low to medium air flow, and medium to high VOC concentrations (>10% LFL) are best for thermal oxidizers. TOX systems can be custom designed to handle high VOC concentrations as compared to CATOX and RTO systems. Typical applications are petrochemical, and chemical airstreams. Special applications are best served by TOX, such as silicone containing airstreams, or processes where secondary heat recovery allows the TOX to operate as efficiently as RTO systems or CATOAX systems because of the heat returned to the process.

Catalytic Recuperative Oxidizers destroy pollutants discharged in the exhaust air of industrial processes. They achieve high VOC destruction efficiency by heating and maintaining a polluted airstream at temperature (typically 600 to 650F) for a set “dwell” time as it passes through catalyst material. The lower operating temperature of a catalytic oxidizer results in much lower fuel use than thermal recuperative oxidizers. VOC destruction efficiency can reach 99+%. Catalytic oxidizers can operate with an integral heat exchanger for fuel savings, or for a lower capital cost, without a heat exchanger. Learn more here.‍

Regenerative thermal oxidizers (RTOs) typically have a 0.5 second to 1.0 second dwell time for most applications.

TOX typically have a 0.5 second to 1.0 second dwell time for most applications.

Up to 99% VOC destruction efficiency; and up to 97+% thermal efficiency.

Catalytic Oxidizers typically operate at temperatures of 500° - 750°F

Regenerative Catalytic Oxidizers (RCO) typically operate at temperatures between 750° - 950°F

Typically 1400° F minimum up to 1550° F depending upon the VOC characteristics. Read more in Operating Temperatures of Different Oxidizers.

An RCO is essentially an RTO with a catalyst layer added. (See What is an RTO?).

VOCs (Volatile Organic Compounds) must combine with oxygen and heat to trigger the chemical reaction that breaks them down into CO₂ and H₂O. There are many successful thermal oxidizer designs that ensure sufficient turbulence, such as introducing the process air at an angle to induce spin or creating internal choke points. The better the mixing and heat distribution, the higher the VOC destruction.

Kono Kogs stands behind every refurbished RTO with warranties that match or exceed those of new equipment OEMs. We have a proven track record of meeting warranty commitments for parts and system performance across a wide range of customers from startups to Fortune 500 companies. Our experienced team provides ongoing technical and maintenance support both on-site, and remotely via KONOConnect to ensure your system operates reliably over the long term.

To ensure quality, we use only top-tier components, conduct thorough inspections, and upgrade parts as needed. Our collaborative planning and extensive oxidizer expertise help deliver flawless projects that our customers trust and recommend.

Induced draft fans are often preferred when handling particulates and solvents with high boiling points, as these solvents can condense and build up on forced draft fan wheels, causing maintenance issues and reduced efficiency.

Chemical, pharmaceutical, and wood products.

Fuel gas injection systems are ideal for applications requiring low NOx and CO emissions and where variable fuel demand exists, such as processes with fluctuating exhaust temperatures or flow rates. They can provide significant fuel savings by precisely controlling fuel input, improving combustion efficiency, and reducing overall energy costs.