Alternative VOC abatement technology improves reliability
A major manufacturer of military vehicles and heavy construction equipment sought a new approach for VOC abatement as an alternative to Regenerative Thermal Oxidizer (RTO) units associated with painting operations. RTO unit complexity and supplemental energy requirements (fuel and electricity) made them costly to operate, unreliable, and contributed to plant CO2 emissions. Treatment reliability is critical to maintaining production, and RTO motor, fan, and switching-valve failures caused periodic unscheduled production shutdowns. As part of an overall effort to improve reliability, reduce compliance costs, and improve margins associated with military and civilian contractual obligations and schedules, the client looked to a continuous moving bed (CMB) as an alternative.
EC&C, the firm that supplies ECT with CMB designs, installed the CMB in 2007 to replace the existing RTOs with a modular design while including additional treatment capacity to address the client’s expanding production. The new VOC abatement equipment included three fluid bed (FB) adsorbers that continuously capture VOCs from the plant’s emissions, an FB desorber that simultaneously renews the media capacity, and a small thermal oxidizer that destroys the organic vapors recovered during treatment. Typical VOC concentrations treated through the VOC abatement process range from about 5 to 15 ppmv during normal operation. The FB units treat air volumes up to 180,000 SCFM, reducing it to about 2,000 cfm at the oxidizer inlet while renewing media capacity. The process concentrates the VOCs by a factor of up to 90 times, with concentrations sufficient to sustain oxidizer operations without supplemental fuel.
Lower costs, lower emissions
The combination of optimized oxidizer operations from volume reduction and eliminating supplemental fuel requirements has reduced CO2 emissions related to air compliance, while reducing energy costs to a fraction of what was previously required. The FB system is inherently simple, requires very little routine maintenance and associated cost while proving highly reliable. The client has saved more than 90 percent on plant energy costs over the past nine years, with a significant contribution to that reduction attributed to this treatment process. Since startup and final commissioning in 2007, the plant has experienced no unscheduled downtime due to emission control equipment failure.
ECT specializes in the application of EC&C continuous moving bed designs to address process compliance and environmental sustainability programs.