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Regenerative Thermal Oxidizers

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A regenerative thermal oxidizer (RTO) is a type of air pollution management equipment that destroys hazardous air pollutants (HAP), volatile natural compounds (VOC) and odorous emissions created throughout industrial processes. RTOs are the commonest air air pollution control technology in use today.

RTO technology makes use of combustion at high temperatures to oxidize air pollutants from industrial exhaust streams, which turns them into CO2 and H2O earlier than they’re launched into the atmosphere. The time period “regenerative” in regenerative thermal oxidizer comes from the ceramic media heat exchanger, which retains heat from the prior combustion cycle to preheat (and partially oxidize) the pollutant-stuffed airstream for the subsequent cycle.

Because RTOs have heat recovery of 95% as an business customary, they’ve the lowest working cost of all thermal oxidizer systems – not to mention the longest service life and highest reliability. Regenerative thermal oxidizers are ideal for process streams with high air movement and low VOC content, achieving VOC destruction of 99%+. It’s even doable for an RTO to operate with no auxiliary fuel use whatsoever if process VOC concentration levels are >/3-4% lower explosive limit (LEL).

(1) A regenerative thermal oxidizer (RTO) works by pushing a pollutant-stuffed airstream by the oxidizer, often with a system fan.

(2) The movement of air via the RTO is managed by valves that direct the airstream into considered one of heat exchangers (chambers containing ceramic media beds).

(three) RTOs have a minimal of beds of ceramic media (saddles and/or structured media block) used as heat exchangers. As dirty air passes via the first media bed, it absorbs heat from the recent ceramic media, then enters the combustion chamber.

(4) In the combustion chamber, dirty air is held at temperature (>1500°F) for a specific dwell time (>.5 seconds). This oxidizes VOCs and HAPs into carbon dioxide and water vapor.

(5) Hot, clean air exits the combustion chamber and moves into the second ceramic media bed which absorbs the heat for reuse.

(6) Cooled, clean air is then exhausted into the atmosphere.

The valves (2) change direction each few minutes which reverses the flow direction, so the heat transfer alternates between the two ceramic media beds. This is what gives RTOs their high fuel effectivity and low operating costs, making them highly desirable VOC abatement systems.

Time, Temperature & Turbulence

Time, temperature and turbulence – aka “The Three T’s”- are critical and co-dependent factors that determine regenerative thermal oxidizer performance.

Time: When airflow is fixed, larger combustion chambers provide longer dwell times. For many applications the dwell time is between .5 and 1 second.

Temperature: The RTO combustion chamber maintains a temperature over 1500°F, which is essential for environment friendly VOC destruction.

Turbulence: VOCs must combine with ample heat and oxygen to set off the chemical reaction (oxidation) that breaks them down into carbon dioxide and water. RTO designs facilitate turbulence to make sure thorough mixing of the polluted process air, growing VOC destruction efficiency.