Flare Regulatory Update

Paper from the AFRC 2018 conference titled Flare Regulatory Update

The Refinery Sector Rule was published on December 1, 2015 with a compliance date of January 30, 2019 for the flare requirements. As refiners worked to come into compliance with the requirements, various items required clarification. The USEPA provided proposed changes to the rule on March 19, 2018 and this presentation will present and discuss the implications of those changes. Additionally, the USEPA has approved a broadly applicable alternative monitoring plan (AMP) for the use of mass spectrometers to determine the composition of flare vent gas. The presentation will present how the broadly applicable AMP fits into the existing monitoring requirements.

AFRC 2018 Industrial Combustion Symposium Salt Lake City, Utah September 2018 Title - Flare Regulatory Update Author: Herman Holm Director - Specialty Environmental Services Spectrum Environmental Solutions, LLC Summary On December 1, 2015, the United States Environmental Protection Agency (USEPA) revised the regulations for the refinery through the Refinery Sector Rule (RSR) revisions to NESHAP CC and UUU (aka MACT CC and MACT UUU). The American Petroleum Institute (API) and American Fuels and Petroleum Manufacturers (AFPM) submitted a request for changes to the proposed rules and the USEPA has proposed modifications to the revised rules on March 19, 2018. Regulatory Overview The USEPA finalized the revisions to the RSR on December 1, 2015, which included new operating requirements for flares. These flare requirements were included in MACT CC. API and AFPM submitted a petition on February 1, 2016 for items related to PRDs, flares, and other areas of the rule. The flare related clarification to MACT CC included the following: Revision to the definition of Flare Purge Gas. The USEPA originally included a reference to a primary reason flare purge gas is added at the flare tip, namely to prevent oxygen infiltration. API and AFPM was concerned that this wording would keep refineries from adding purge gas for other safety reasons. The USEPA has proposed to revise the definition to clarify that flare purge gas may also include gas needed for other safety reasons. The USEPA proposes to revise the definition of flare purge gas as: Flare purge gas means gas introduced between a flare header's water seal and the flare tip to prevent oxygen infiltration (backflow) into the flare tip or for other safety reasons. For a flare with no water seal, the function of flare purge gas is performed by flare sweep gas and, therefore, by definition, such a flare has no flare purge gas. Revision to the definition of Flare Supplemental Gas. The USEPA originally included the language that flare supplemental gas included all gas that improves the combustion in the flare combustion zone. API and AFPM were concerned that this definition could be interpreted to include assist air and assist steam, even though the term is used throughout the rule to only include gases that increase combustion efficiency by raising the heat content of the combustion zone. This is shown in the rule as the definition of flare vent gas specifically includes flare supplemental gas and specifically excludes total steam or assist air. Additionally, API and AFPM commented on how the rule incorrectly assumes that supplemental gas is always natural gas and uses the term "natural gas" in the equations and could potentially limit a refiner's ability to use fuel gas as supplemental gas. The USEPA proposes to revise the definition of flare supplemental gas as: Flare supplemental gas means all gas introduced to the flare to improve the heat content of combustion zone gas. Flare supplemental gas does not include assist air or assist steam. Additionally, the USEPA proposes to replace all occurrences of the term "supplemental natural gas" with the defined term "flare supplemental gas." Consistent use of the terms Pressure Relief Device and Relief Valve. API and AFPM commented that the rule interchangeably uses the term "relief valve" and the term "pressure relief device," and requested that only the term "pressure relief device" be used as a relief valve is only one type of pressure relief device. The USEPA agreed and is proposing to add a definition of pressure relief device, proposing to revise the definition of relief valve, and proposing to consistently use the term "pressure relief device" throughout the rule. Clarification of individual prevention measures. Section 40 CFR 63.648 (j)(3)(ii) provides a list of options for three redundant release prevention measures that must be assessed for affected PRDs. The prevention measures in include: (A) flow, temperature, level, and pressure indicators with deadman switches, monitors, or automatic actuators; (B) documented routine inspection and maintenance programs and/or operator training (maintenance programs and operator training may count as only one redundant prevention measure); (C) inherently safer designs or safety instrumentation systems; (D) deluge systems; and (E) staged relief system where initial pressure relief valve (with lower set release pressure) discharges to a flare or other closed vent system and control device. The API and AFPM requested clarification as to whether two prevention measures can be selected from the list in 40 CFR 63.648(j)(3)(ii)(A). The rule does not state that the measures in paragraph (j)(3)(ii)(A) are to be considered a single prevention measure. The USEPA proposes to clarify this issue and are proposing to revise 40 CFR 63.648(j)(3)(ii)(A) to indicate that independent, non-duplicative systems count as separate redundant prevention measures. Flare Lower Steam Air Entrainment Clarification. API and AFPM requested clarification regarding assist steam line designs that entrain air into the lower or upper steam at the flare tip. The industry representatives noted that many of the steam-assisted flare lines have this type of air entrainment and likely were part of the dataset analyzed to develop the standards established in the 2015 final rule for steam-assisted flares. API and AFPM concludes that these flares should not be considered to have assist air and that they are sufficiently regulated under the final standards for steam-assisted flares. Because flares with assist air are required to comply with both a combustion zone net heating value (NHVcz) and a net heating value dilution parameter (NHVdil), there is increased burden in having to comply with two operating parameters. The rule includes the following: • Assist air is defined to mean all air intentionally introduced prior to or at a flare tip through nozzles or other hardware conveyance for the purposes including, but not limited to, protecting the design of the flare tip, promoting turbulence for mixing, or inducing air into the flame. • Assist air includes premix assist air and perimeter assist air. • Assist air does not include the surrounding ambient air. API and AFPM indicated that "Air entrainment through steam nozzles is intentionally introduced prior to or at the flare tip and, therefore, it is considered assist air. However, if this is the only assist air introduced prior to or at the flare tip, it is reasonable in most cases for the owner or operator to only need to comply with the NHVcz operating limit. This is because an exceedance of the NHVcz operating limit would also cause an exceedance of the NHVdil operating limit in many cases." The USEPA calculated the amount of air that must be entrained in the steam to cause a flare meeting the NHVcz operating limit of 270 British thermal units per standard cubic foot (Btu/scf) to be below the NHVdil operating limit of 22 Btu per square foot (Btu/ft2). As the NHVdil parameter is a function of flare tip diameter, flare tips with an effective tip diameter of >9 inches, there are no flare tip steam induction designs that can entrain enough assist air to cause a flare operator to have a deviation of the NHVdil operating limit without first deviating from the NHVcz operating limit. Therefore, the USEPA is proposing to allow refinery flares whose only assist air is from perimeter assist air entrained in lower and upper steam at the flare tip and with a flare tip diameter of > 9 inches to comply only with the NHVcz operating limit. Clarification for determining air flow rates. For air assisted flares, the USEPA is providing clarification on determining air flow rates. The rule specifically provided for the use of engineering calculations for determining the flow rate; however, the USEPA received a question as to whether or not this allowed the use of fan curves for determining air assist flow rates. In the 2015 final rule in the introductory paragraph of 40 CFR 63.670(i), the USEPA had included a statement that continuously monitoring fan speed or power and using fan curves is an acceptable method for continuously monitoring assist air flow rates. To further clarify this point, the USEPA is proposing to include specific provisions for continuously monitoring fan speed or power and using fan curves for determining assist air flow rates. Clarification for visible emissions monitoring. As the final rule was initially written, there was some ambiguity as to whether a facility would be required to flare regulated materials in order to conduct the required visible emissions monitoring. The UESPA agreed that it is not reasonable to require refiners to flare regulated materials intentionally in order to conduct a visible emissions compliance demonstration. The USEPA is proposing to clarify that the initial 2-hour visible emissions demonstration should be conducted the first time regulated materials are routed to the flare. Additionally, the USEPA is proposing to clarify that the daily 5-minute observations must only be conducted on days the flare receives regulated material and that the additional visible emissions monitoring is specific to cases when visible emissions are observed while regulated material is routed to the flare. Smokeless Capacity timeframe clarification. API and AFPM requested that the USEPA specify the averaging period for establishing the limit for the smokeless capacity of the flare and that it be a 15-minute average consistent with other flow parameters and velocity requirements. Owners or operators would use the cumulative flow rate and/or flare tip velocity determined according to 40 CFR 63.670(k) for assessing exceedances of the smokeless capacity. The USEPA is proposing to clarify that the owner or operator must establish the smokeless capacity of the flare in a 15-minute block average and that the exceedance of the smokeless capacity of the flare is based on a 15-minute block average. Flare Tip Velocity unit correction. The USEPA is proposing a correction of an error in the units for the cumulative volumetric flow used in the flare tip velocity equation in 40 CFR 63.670(k)(3). The units will be modified to standard cubic feet rather than actual cubic feet consistent with the cumulative volumetric flow monitoring requirements in 40 CFR 63.670(i)(1). Flare Vent Gas Measurement Capabilities. Industry stakeholders with input from vendors have communicated concerns over the ability to meet the flare vent gas flow rate minimum accuracy requirements in 40 CFR 60.107a(f)(1)(ii) and in Table 13 of 40 CFR part 63, subpart CC when vent streams have low molecular weight. These requirements specify • an accuracy of ±20% of the flow rate at velocities ranging from 0.1 to 1 foot per second and • an accuracy of ±5% of the flow rate for velocities greater than 1 foot per second. Stakeholders stated that the accuracy requirements could not be met for some historical flow events when molecular weight of the flare vent gas was low. The EPA recognizes that flares can receive a wide range of process streams over a wide range of flows. The USEPA is proposing to clarify that certification of compliance for these flare vent gas flow meter accuracy requirements can be made based on the typical range of flare gas compositions expected for a given flare. Additional Minor Corrections. §63.670(o) - Correct the reference to "paragraphs (o)(1) through (8)" to "paragraphs (o)(1) through (7)." §63.670(j)(6) - Correct the reference to subparagraphs "(j)(6)(i) through (v)" to "(j)(6)(i) through (iii)." Provision Proposed Revision §63.670(o)(1)(ii)(B) - Correct the reference to paragraph "§63.648(j)(5)" to "§63.648(j)(3)(ii)(A) through (E)." Table 13, Hydrogen Analyzer Requirements for Sampling Location - Add "Where feasible" to the description of sampling location for the hydrogen analyzer. Conclusions Based on requests from API, AFPM, and other stakeholders, the USEPA has proposed revisions to a few of the flare requirements found in MACT CC. While some clarifications were for minor errors and clarifications, others clarified potential larger compliance concerns. These clarifications were proposed prior to the compliance date; however, the API and AFPM have already submitted another request for correction/clarification on the rule on May 25, 2018. We will have to see whether these new requests can be addressed prior to the compliance datae of January 30, 2019.