Develop a program that prioritizes and emphasizes inspections of FCC units in refineries that operate HF alkylation units (for example, under EPA’s National Compliance Initiative called Reducing Risks of Accidental Releases at Industrial and Chemical Facilities). As part of this program, verify FCC unit safeguards that prevent explosions during transient operation (including startup, shutdown, standby, and emergency procedures). At a minimum the program will verify the following specific safeguards:
a) Implementation of the reactor steam barrier, or a similar inert gas flow, to maintain an inert barrier at an elevated pressure between the main column (containing hydrocarbon) and the regenerator (containing air);
b) Purging the main column with a non-condensable gas as needed to prevent a dangerous accumulation of oxygen in the main column overhead receiver;
c) Monitoring to ensure that there is a sufficient non-condensable gas purge of the main column to prevent a dangerous accumulation of oxygen in the main column overhead receiver (either through direct measurement of the oxygen concentration and/or through engineering calculation);
d) Monitoring of critical operating parameters for flows, pressures, pressure differences, and catalyst levels;
e) Documentation of consequences of deviating from the transient operation safe operating parameters and of predetermined corrective actions; and
f) Inclusion of the above items in the appropriate FCC operator training curricula.
This recommendation is in addition to the recommendations to EPA relating to hydrofluoric acid outlined in the CSB’s report on the 2019 fire and explosions at the Philadelphia Energy Solutions refinery. In that report, the CSB recommended (1) that the EPA prioritize inspections of refinery HF alkylation units to ensure units are complying with API good practice guidance, (2) to require petroleum refineries with HF alkylation units to evaluate inherently safer technology, and (3) to initiate prioritization and, as applicable, risk evaluation of HF under the Toxic Substances Control Act.