The Regenerative Thermal Oxidizer (RTO) technology has evolved over the past several decades to become the preferred destruction device for hazardous air pollutants (HAPs), volatile organic compounds (VOCs) and odorous emissions. The energy efficient operation and high destruction efficiency make it a great emission control device for a wide variety of industrial processes. Within the RTO, destruction efficiencies over 99% are achieved through the process of high temperature thermal oxidation. Pollutants are converted to carbon dioxide and water vapor while reusing the thermal energy generated during combustion to reduce operating costs.
Standard RTOs are commonly used throughout the composites industry for emission and odor abatement. However, unique aspects of Carbon Fiber processing dictate several oxidizer modifications in order to maintain system effectiveness, reliability and safety. Theoretically, emissions from the LT and HT Furnaces as well as the ovens can both be handled by the RTO; however it is used most frequently for the Oxidation Oven exhaust. The regenerative component to the RTO make is ideal for handling high flow, low concentration streams. With achievable thermal efficiencies over 97% the RTO is capable of operating with little to no supplemental fuel use.
On most applications, airflow is typically pushed through an RTO in a forced draft configuration. This reduces main system fan size and the electrical consumption required for it to push process air into oxidizer. Due to the Hydrogen Cyanide (HCN) found in Carbon Fiber processing, many RTOs on this application are supplied in an induced draft configuration. The main system fan must be oversized to pull air through the oxidizer but it will ensure that all HCN emissions are drawn into the oxidizer for destruction, protecting the company’s employees and neighborhood from a potential situation.
Whenever oxidizing siloxane vapors in an RTO, considerations must be made to minimize the impact of silica dust build up in the heat recovery beds. The formation of the inorganic silica particulate starts at elevated temperatures and tends to accumulate within the media beds. For applications with ambient inlet temperature that would indicate that the silica drops out in the media beds where the temperatures are higher.
There are many other design considerations to explore in terms of efficiences, maintenance and servicing. No matter how well an overall system is designed, it cannot continue to operate at a high efficiency level without proper maintenance. A handful of small inefficiencies in system operation can lead to a large operating cost bill over the course of a year. This is especially true for RTOs used in Carbon Fiber processing.
Learn more about Regenerative Thermal Oxidizers with this interactive diagram.