Publications by Wingra Engineering Staff

 

"Influence of Emission Estimates on a BACT Determination for Iron Foundry Core Making Operations"

Steven J. Klafka, PE, DEE
Kurt W. Jacobsen, PE

ABSTRACT

Under the Prevention of Significant Deterioration air quality regulations, new air pollution sources must control their emissions using Best Available Control Technology (BACT).  This case study reviews the issuance of a new source permit for phenolic-urethane coldbox core making operations at an iron foundry in Indiana.  The finished cores are subsequently used to form the internal spaces within the iron casting.  The project BACT analysis required an estimate of emissions during each phase of the process, including mixing of the sand and binder resin, activation of the resin using a catalyst, and storage of the finished cores.  Volatile organic compound (VOC) emissions are generated by the handling of the phenolic-urethane resin and release of the triethylamine catalyst.  The traditional emission control system is a packed bed scrubber using a sulfuric acid reagent to capture the catalyst for reuse.  An alternative control option considered in the BACT analysis was regenerative incineration. While the packed system would control the catalyst emissions, incineration would also control the VOC emissions from resin handling.  The incineration system would be considered BACT if the overall cost effectiveness in units of dollars per ton of pollutant removed was deemed acceptable by the state regulatory agency.  The cost effectiveness varied depending on the procedure used to estimate uncontrolled VOC emissions from resin handling.  These procedures include the American Foundryman's Society Form R booklet, compliance stack test results on similar core making operations using USEPA Methods 25 and 25A, a laboratory study of evaporative resin losses by the Ohio Cast Metals Society, and laboratory tests by resin manufacturers. Accurate emission estimates were essential to establish that incineration was not cost effective and a traditional packed bed scrubber represented BACT.