Regenerative thermal oxidizers, commonly referred to as RTOs, are essential in the effective and economical removal of hazardous air pollutants (HAPs) and volatile organic compounds (VOCs) from industrial emissions. These thermal oxidizers are specialized combustion systems incorporated into the ventilation of industrial operations that produce potentially harmful pollutants. As exhaust gases pass through the oxidizer, it is heated to approximately 1500°F, facilitating the breakdown of HAPs and VOCs into benign substances such as carbon dioxide and water vapor, which can subsequently be released into the atmosphere. RTOs typically employ conventional metallic shell-and-tube heat exchanger systems, whereas regenerative thermal oxidizers utilize ceramic media beds that offer superior thermal efficiencies. In a dual-bed regenerative thermal oxidizer, the incoming process emissions are either drawn or forced through the initial ceramic bed by means of a high-pressure fan and pneumatic flow control valves. The contaminated stream exits the ceramic bed and enters the combustion chamber, where burners effectively decompose the harmful compounds with a destruction efficiency exceeding 99%. The resulting purified stream is then directed through a secondary ceramic bed, where it can transfer up to 97% of its heat value to the exchange medium. Regenerative thermal oxidizers capitalize on this recovered heat by periodically reversing the flow direction through pneumatic valves. The ceramic bed that has absorbed heat from the purified stream is subsequently employed to preheat the incoming emissions, while clean, cool air is released into the atmosphere.
RTO equipment typically operates with burners that utilize gas or fuel to heat the oxidation chamber during the start-up phase, facilitating the oxidation of VOCs. In the case of flameless RTOs, the absence of a burner means there is no flame and consequently no NOX emissions produced. Instead, the oxidation chamber is heated by electrical resistances installed within it.
During the start-up process, these electric resistances function at full capacity to achieve the necessary temperature in the RTO oxidation chamber. Once operational, the electricity consumption will vary based on the VOC concentration at the inlet and its calorific value. If the concentration exceeds the auto-thermal threshold, the resistances will deactivate. Conversely, if the concentration falls below this threshold, the thyristors will adjust the power to the resistances to maintain the oxidation chamber at the required temperature, ensuring effective oxidation of VOCs.
Electrical RTO technology offers several benefits like Very High VOC elimination,High thermal efficiency, Integrated design with small dimensions and simple installation,Reduced maintenance and very high reliability, Less noise around the equipment due to the lack of a burner fan, Low operating costs, very minimal maintenance etc.
Our client is a German company with a rich legacy spanning six decades in the field of industrial air pollution control and energy recovery systems. The client is currently working on a range of eRTO designs with varying capacities. Niharika Computational Engineering Solutions (NCES) has been assigned the task of performing Computational Fluid Dynamics (CFD) analysis and providing the design team with technical recommendations derived from the CFD findings.
The NCES team has successfully completed CFD analysis for approximately 12 different eRTO designs and has delivered all outputs well in advance of project deadlines, ensuring a high degree of accuracy in the CFD analysis.
Precisely capturing the velocity and thermal boundary layer around approximately 2500 to 4000 closely arranged heater fins presented significant challenges related to mesh count and quality metrics.
The NCES team, with a legacy of over thirty years in CFD analysis, has adeptly addressed these practical challenges linked to the intricate eRTO CFD model and has performed CFD analysis with complete assurance.
Our accurate CFD analysis outcomes have empowered our client to make timely and well-informed technical decisions.
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