Background & Applicability
On September 29, 2015, EPA issued its final Risk and Technology Review (RTR) for the Petroleum Refinery Sector, also known as the Refinery Sector Rule (RSR), which was proposed on June 30, 2014. The final rule was published in the Federal Register on December 1, 2015, with an effective date of February 1, 2016. The final rule requires continuous fenceline monitoring for benzene and calls for a comprehensive program of process changes and pollution prevention targeted at reductions in visible flare emissions and releases by pressure release devices (PRDs). The new requirements also mandate additional reductions from storage tanks and delayed coker operations, some of which had no controls required previously, as well as new control requirements for maintenance activities and episodic releases that were previously unregulated.
The RTR rule applies only to major sources of hazardous air pollutants (HAPs) and not to area sources. A major source is defined as 10 tpy of any one HAP and/or 25 tpy of combined HAPs.
This final rule is based on the risk and technology review of two refinery emissions standards: the National Emission Standards for Hazardous Air Pollutants From Petroleum Refineries (40 CFR Part 63 Subpart CC, "Refinery MACT 1") and the National Emission Standards for Hazardous Air Pollutants for Petroleum Refineries: Catalytic Cracking Units, Catalytic Reforming Units, and Sulfur Recovery Units (40 CFR Part 63 Subpart UUU, "Refinery MACT 2").
RSR-Affected Emission Sources
MACT CC (Refinery MACT I) Affected Emission Sources
- Delayed Coking Units (DCUs)
- Miscellaneous Process Vents (MPVs), including maintenance vents
- Flares as control devices
- Storage tanks
- Fugitive equipment leaks (through fenceline monitoring)
- Marine loading
MACT UUU (Refinery MACT II) Affected Emission Sources
- Catalytic Reformer Units (CRUs)
- Fluid Catalytic Cracking Units (FCCUs)
- Sulfur Recovery Units (SRUs)
Big Picture Requirements of the New RSR Rule
The main provisions of the RSR include the following:
- New emissions controls for refinery storage tanks, CRUs, and DCUs;
- Work practice standards to reduce emissions from atmospheric PRDs and flares;
- Continuous benzene monitoring at the refinery fenceline "to improve the management of fugitive emissions" per the rule preamble;
- Elimination of exemptions to emission limits for uncontrolled releases during start-up, shutdown, and malfunction;
- Technical corrections and clarifications to the Petroleum Refinery New Source Performance Standards (NSPS) J and Ja.(not covered in this article)
Reductions from Storage Tanks, Catalytic Reforming Units, and Delayed Coking Units
Under the new rule, storage vessels with smaller capacities and lower vapor pressure content must implement certain requirements to control emissions previously applicable only to larger and higher-pressure material storage vessels. For example, the original capacity and vapor pressure limits were 47,000 gallons and 1.5 psia (maximum monthly). The new cutoffs under the refinery sector rule, listed below, are similar to the HON (Hazardous Organic NESHAP – 40 CFR Subpart F, G, H, and I). Additionally, the HAP content remains at 4%.
- 20,000 – 40,000 gallons and above, 1.9 psia
- Above 40,000 gallons, 0.75 psia
Furthermore, Group 1 storage vessels must comply with the requirements of Generic MACT [40 CFR Part 63, Subpart WW] and thus will be potentially subject to additional fittings, guide-pole controls, etc.
For DCUs at existing refineries, the new rule establishes the following options for maximum venting pressure or temperature:
- Coke drum cannot vent to atmosphere until the pressure is at < 2 psig averaged over 60 decoking events; OR
- Temperature < 220 °F averaged over 60 decoking events.
The rule also establishes new provisions for decoking operations with water overflow as well as double quenching.
The new rule removed the control exemption for CRUs during active purging when the reactor pressure is ≤5 psig because EPA believes that active purge systems can direct the gas to a control system regardless of system pressure.
Reductions in Releases from Pressure Relief Devices
The final rule establishes the following work practice standards for releases from PRDs to the atmosphere:
- Must be equipped with a monitoring device (such as a rupture disk indicator, magnetic sensor, motion detector on the PRD valve stem, flow monitor, or pressure monitor) that identifies a pressure release, records the time and duration, and notifies operators that a release is occurring.
- Must apply a minimum of three prevention measures to each PRD, such as flow, temperature, level and/or pressure indicator meters; documented routine inspection and maintenance programs; or safety instrumentation systems.
In the event of a release, facilities are required to perform a root cause analysis to determine the cause of the PRD release event and to quantify and report the amount of the release. Following a release, facilities must implement corrective action. Releases caused by operator error or negligence and repeat release events are considered deviations and must be reported in semiannual compliance reports.
Reductions in Flare Emissions
Under the new rule, new flare provisions have been implemented to further assure 98% combustion efficiency and to supersede the flare General Provision requirements. Like PRDs, repeat events outside the work practice requirements are considered deviations. Flares must now meet the following operating conditions:
- Continuously lit pilot flame at all times
- No visible emissions when flare vent gas is below the smokeless capacity of the flare
- Net heating value for the combustion zone gas (NHVcz), ≥ 270 BTU/ft3 on a 15-minute average, estimated using flare vent gas composition monitoring
- Compliance with one of two options for flare tip velocity
Continuous Fenceline Monitoring
The rule establishes a work practice standard of continuous, but not necessarily real-time, monitoring, to improve the management of fugitive emissions from sources such as leaking equipment and wastewater treatment. All refineries must utilize a network of passive diffusive tube samplers at the refinery fenceline, collecting a sample at least once every 14 days. The monitors must encircle the refinery fenceline. If fenceline concentrations exceed the 0.9 µg/m3 threshold, corrective action is required.
Removal of Exemption for Releases during Start-up, Shutdown, and Malfunctions
The final rule eliminates the exemption to emission limits for uncontrolled releases during startup, shutdown, and malfunction (SSM) events. In its place, EPA has finalized alternate work practices to be performed during startup, shutdown, and hot standby, including the requirements discussed for PRDs and classifying the control device bypass of a Group 1 miscellaneous process vent as a violation. Other alternative work practices include the following:
- Perform a root-cause analysis and implement corrective action following certain emergency flaring events during SSM periods, limit the number of events allowed to occur over a three-year period before it is considered a deviation, and develop prevention measures, such as a flare management plan.
- MPVs can now be classified as Maintenance Vents and, if these vent meet specified criteria, emissions can be released to the atmosphere.
Additionally, the rule promulgates standards for FCCUs during SSM events. During startup, shutdown, and hot standby of FCCUs, refineries can choose to comply with one of two emissions standards for metal HAPs and one of two emissions standards for organic HAPs.
- For metal HAP emissions:
- Comply with either NSPS requirements, PM limits, and nickel limits; OR
- Maintain inlet velocity to the primary internal cyclones of the catalyst regenerator at or above 20 ft/sec.
- For organic HAP emissions:
- Comply with either specified operating limits, NSPS requirements, or CO emission limits; OR
- Maintain the O2 concentration in the exhaust gas from the catalyst regenerator at or above 1% volume.
The rule also includes standards for SRUs. During startup and shutdown, they must:
- Send any startup or shutdown gases to a flare, thermal oxidizer, or incinerator, OR
- Comply with NSPS requirements or the total reduced sulfur emission limits in the rule.
Recommended Path Forward
As a first step, refineries should generate an action plan with checklists via an Excel-based (or similar) workbook to document applicable amendment requirements, compliance gaps, and compliance deadlines. This workbook could be organized by source category, such as tanks, vents, and flares. With deadlines ranging from 2016 to 2019, and each deadline triggering multiple requirements, it is critical to identify action items with due dates to meet the multiple deadlines.