ENV-16-76 Finding a Correlation: FCCU Operating Parameters vs HCN Emissions

Description:

Hydrogen cyanide (HCN) emissions from fluid catalytic cracking units (FCCUs) have historically been assumed to be inconsequential, such that they did not require separate permitting, emissions reporting, and or regulatory requirements for control. In 2011, the United States Environmental Protection Agency (EPA) initiated an Information Collection Request (ICR) as part of their emission standard review and “residual risk” evaluation for the existing refinery New Source Performing Standards (NSPS) and Maximum Achievable Control Technology (MACT) standards. The ICR included a stack testing component, part of which required 10 refineries to stack test their FCCUs for selected organic and inorganic hazardous air pollutants (HAPs), including HCN. The results of the stack tests demonstrated that HCN emissions from FCCUs were higher than previously considered. As such, the EPA revised the previously published AP-42 emissions factor and updated MACT Subpart UUU to include an HCN stack testing requirement (in addition to other changes).