New approach to VOC abatement
A major international automotive manufacturer interested in a new approach to volatile organic compound (VOC) abatement associated with painting operations invested in a continuous moving bed as part of a carbon footprint reduction demonstration project at its assembly operations in the Southeastern US. Automotive paint emissions are usually treated with recuperative thermal oxidizers (RTO), complex units that require supplemental fuel to sustain operating conditions. Not only did the RTO fuel consumption contribute to the plant’s CO2 emissions—one element of the high cost of operating and maintaining the RTO units as emission control devices—but its complexity caused occasional motor, fan and switching valve failures, which then caused periodic unscheduled production shutdowns.
The customer was looking beyond the simple business case of reducing operation costs right from the start of this project; they wanted to adopt an internal corporation-wide goal to exceed regulatory requirements as a good “corporate citizen,” committed to capturing sources with very low VOC content, beyond the requirements of permit compliance. The treatment scope of supply also called for concurrent CO2 emission reductions associated with the plant’s entire operation. The internal goal for CO2 emission reductions established a target for 2020 that was much lower than that mandated by the general global corporate and governmental targets.
Reduced emissions and energy costs
In 2012, an EC&C continuous moving bed VOC abatement system was installed to replace the existing RTOs, and the treatment scope expanded to include untreated emissions sources previously vented into the atmosphere under various environmental permits. The VOC abatement equipment included a fluid bed adsorber to continuously capture the VOCs from plant emissions, a fluid bed desorber to simultaneously renew the media capacity, and a small thermal oxidizer to destroy the organic vapors recovered during treatment. Typical VOC concentrations treated through the VOC abatement process range from about 20 to 50 ppmv during normal operations. The treated air volume of 105,000 SCFM is reduced to about 1,500 cfm by stripping the adsorbent in the desorber to renew media capacity. The process concentrates the VOCs by a factor of about 70 times, which is sufficient to sustain oxidizer operations without supplemental fuel.
The combination of volume reduction and eliminating supplemental fuel requirements has reduced CO2 emissions from air compliance operations to nearly zero, far exceeding the 2020 target and nearly 8 years ahead of schedule.
The client has saved over 80% on plant energy costs in the last four years, a significant contribution to that reduction attributable to this treatment process. Since the system’s startup in 2012, the plant has experienced no unscheduled down time due to emission control equipment failure, and has exceeded internal 2020 CO2 emission reduction goals. Our vapor treatment technology will be used as part of a total plant rebuild in 2016.
ECT specializes in the application of EC&C continuous moving bed designs to address process compliance and environmental sustainability programs.