In many industrial applications producing VOCs, there is a high volume of air containing low levels of VOCs. This increases capital costs by requiring the capacity to handle a large airflow, yet it reduces system efficiency because of the increased BTU requirement to oxidize the VOCs. A rotary concentrator utilizing a zeolite wheel can help concentrate the VOCs, reducing the airflow volume requiring control while also increasing the available BTUs by the same ratio.
Zeolites are microporous material consisting of aluminosilicates. They occur naturally or can be synthetically manufactured. The pores, based on their size and structure have affinity for a variety of compounds. In addition to VOC concentration, zeolites have the capacity to be used for dehumidification and water purification. Their capability to absorb and desorb VOCs is dependent on their specific structure and the VOCs or range of VOCs requiring control.
The zeolite is mounted in a rotating wheel system, with on segment absorbing the VOCs with clean exhaust exiting. Another segment is having the VOCs desorbed using heat recovered from the thermal oxidizer used for final destruction of the VOCs. Generally speaking, when the affinity for the contaminant is good, a wheel can provide a 10:1 concentration ratio or better; the destruction efficiency (DRE) is typically in the range of 95-98 percent, depending on the VOC load and composition.
A rotary concentrator system can be an excellent way to improve efficiency, but a clear picture of the components of the process must be developed to ensure proper design. If your facility generates a high-volume, low-concentration (HVLC) process, call NESTEC so we can discuss your most effective control technology.
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