In a direct final rule affecting petroleum refineries subject to 40 CFR Part 60 Subpart Ja, the EPA has issued a revised definition of delayed coking unit.  The revision removes “process piping and associated equipment such as pumps, valves, and connectors” from the definition.  The effect of the revision is that “small changes” associated with this equipment do not constitute a regulatory modification and, therefore, do not subject the operator to additional requirements. 

Delayed coking units are used at refineries to upgrade heavy ends (“bottom-of-the-barrel” crude petroleum) into a higher-value product.  The process requires high temperatures for an extended period of time. 

Regulated elsewhere

According to the EPA, emissions from process piping and the associated pumps, valves, and connectors deleted from the definition are already covered under 40 CFR Part 60, Subparts GGG or GGGa.  Furthermore, the controls required under Subpart Ja are intended to addresses emissions from the delayed coking unit’s process vent, says the Agency; these controls are not intended to address emissions from the equipment deleted from the definition.

The EPA states:
“Although we included process piping and associated equipment in the definition of delayed coking unit because it is necessary to operate the delayed coking unit, the inclusion of this equipment within the definition results in very minor changes, such as adding a few valves and connectors for a new sample point or pressure gauge, to be considered a ‘modification’ of the delayed coking unit.  This was an inadvertent result as the EPA did not intend for such small changes to process piping and associated equipment (such as pumps, valves, and connectors, which are regulated elsewhere), to constitute a modification of the delayed coking unit under 40 CFR Part 60, Subpart Ja.”

Depressurization not needed

Absent the revised definition, making the small changes noted by the EPA would force operators into “immediate compliance” with the coke drum vent control requirements at 40 CFR 60.103a(i).  This provision requires depressurization of each coke drum to 5 pound per square inch gauge (psig).  Until the 5 psig pressure is reached, the coke drum steam exhaust must be managed in an enclosed blowdown system and the uncondensed vapor must either be recovered (e.g., sent to the delayed coking unit fractionators) or vented to the fuel gas system, a fuel gas combustion device, or a flare.

The direct final rule also removes a redundant definition of delayed coking unit from 40 CFR 60.101a.

The rule was published in the December 19, 2013, FR.