A February fire at a 190,000-barrel-per-day oil refinery has been cited as the cause behind several in a series of air quality violations that Delaware state regulators agreed to settle with refinery owners this week.
On top of a $1 million settlement reached last year with the Delaware Department of Natural Resources and Environmental Control, Delaware City Refining Company agreed to pay an additional $70,000 for violations between November 2018 and June at their Delaware City refinery.
In the latest set of violations DCRC was charged with releasing nearly 335,400 pounds of carbon monoxide, 65,000 pounds of sulfur dioxide, 11,500 pounds of hydrogen sulfide, 4,500 pounds of ammonia and 550 pounds of hydrogen cyanide over the course of five separate incidents, the settlement document states.
Cold weather set the conditions for the February fire. In preparation for replacement, insulation had been stripped off a 3-inch pipe nearly two week earlier. The pipe froze and ruptured, triggering a hydrocarbon release in the crude unit that ignited two separate fires within a 15-minute span.
Heat also caused a 6-inch line carrying heavy naphtha and a 3-inch low pressure off-gas line to fail.
Soon, one of two compressors controlling the flow of flammable gas to the emergency flare broke down. The other compressor, overwhelmed by demand, allowed gas to back up through the system and further feed the fire for nearly 90 minutes.
Firefighters fought the blaze for nearly 12 hours before extinguishing it. Flaring continued for many hours after that.
In January, a breakdown involving the refinery’s fluid coking unit resulted in a 14-hour release of air pollutants, accounting for the largest amount of the violations. Likewise, a coker breakdown on March 14 again activated emergency flaring. A separate incident the following day also required flaring.
In May, an unplanned shutdown of a polymerization unit as the refinery returned to operation after a turnaround again precipitated flaring.