| (6) For flares that at all times receive greater than 95% of an individual HRVOC, the owner or operator may use process knowledge to determine net heating value for demonstrating compliance with §115.722(d) of this title. (g) For an emergency flare, as defined in §115.10 of this title, subject to the requirements of this division, the owner or operator shall: (1) comply with the continuous monitoring requirements in subsection (d) of this section; or (2) use process knowledge and engineering calculations to determine compliance with the requirements of §115.722(a) - (d) of this title during an upset event. If this option is selected the owner or operator shall comply with the following: (A) for emergency flares equipped with a physical seal (e.g., a water seal) that prevents emissions from being sent to the flare except during an upset event, the owner or operator shall install, calibrate, operate, and maintain, according to manufacturer's specifications, a continuous monitoring system that: (i) monitors the status of the physical seal to ensure that emissions are not directed to the flare except during an upset event; (ii) automatically records the time and duration of each event when emissions are sent to the flare; and (iii) verifies that the physical seal has been restored after each event; (B) for emergency flares not equipped with a physical seal that prevents emissions from being sent to the flare except during an upset event, the owner or operator shall: (i) install, calibrate, operate, and maintain, according to manufacturers' specifications, a flow monitoring or indicating system to determine and record the time and duration of each event when emissions are sent to the flare; and (ii) determine through process knowledge, engineering calculations, or actual testing, the baseline flow rate from any purge/sweep gas and the minimum flow rate indicative of an upset event; (C) the owner or operator shall develop, implement, and follow a written monitoring plan to satisfy the requirements of subparagraph (A) or (B) of this paragraph. The monitoring plan must include: (i) specifications for all monitors used to satisfy the requirements of subparagraph (A) or (B) of this paragraph; (ii) the engineering calculations, process information, and actual testing used to determine volumetric flow rate, flare tip exit velocity, net heating value, and HRVOC emissions for compliance with §115.722(a) - (d) of this title; and (iii) at a minimum, quarterly inspections of the continuous monitoring system to ensure proper operation; (D) upon written request by the executive director, the monitoring plans required in accordance with subparagraph (C) of this paragraph shall be submitted within 30 days for review. The executive director may require additional or alternative monitoring requirements; and (E) the flare's actual exit velocity for each activity must be calculated on a one-hour block average basis, corrected to standard temperature and pressure and the unobstructed (free) cross-sectional area of the flare tip, according to 40 CFR §60.18(f)(4). The HRVOC hourly average mass emission rates from the flare must be calculated, using total HRVOC sent to the flare calculated based on process knowledge or actual measurement, assuming a 99% destruction efficiency for ethylene and propylene and a 98% destruction efficiency for all other HRVOCs when the flare meets the net heating value and exit velocity requirements of 40 CFR §60.18. During each one-hour block period when the flare does not meet the net heating value or exit velocity requirements of 40 CFR §60.18, a destruction efficiency of 93% must be assumed to calculate HRVOC mass emission rates. (h) Flares other than emergency flares that temporarily receive HRVOC emissions during any operation that is not a scheduled or unscheduled maintenance, startup, or shutdown activity as defined in §101.1 of this title must satisfy the following requirements. (1) The flare must not be operated in HRVOC service for more than 336 hours at the plant site in any 12 consecutive months. (2) The total number of hours for which a site may send HRVOCs temporarily to multiple flares as described in this subsection must not exceed 672 hours in 12 consecutive months. (3) In lieu of the flow monitoring requirements of subsection (d)(1) of this section, the owner or operator may use one of the following to demonstrate compliance with §115.722(a) - (d) of this title: (A) process knowledge; (B) actual measurement; or (C) for flares that temporarily receive HRVOC emissions from flare systems that are monitored in accordance with subsection (d) of this section, the flow monitoring data from the monitored flare system may be used as data substitution. Maximum one-hour average flow rate, excluding data from startups, shutdowns, maintenance, or emissions events, from the previous 30 operational days must be used to determine compliance with §115.722(a) - (d) of this title. (4) In lieu of implementing the continuous monitoring requirements specified in subsection (d) (2) of this section, the owner or operator may use one of the following to demonstrate compliance with §115.722(a) - (d) of this title: (A) for all flares in temporary HRVOC service, daily sampling in accordance with subsection (d) (4) of this section to determine net heating value and HRVOC concentrations; or (B) for flares that temporarily receive HRVOC emissions for less than 72 consecutive hours from flare systems that are monitored in accordance with subsection (d) of this section, the monitoring data from the monitored flare system may be used as data substitution to satisfy compliance with §115.722(a) - (d) of this title. Maximum one-hour average total HRVOC concentrations and minimum one-hour average net heating value, excluding data from scheduled startups, shutdowns, maintenance, or emissions events, from the previous 30 operational days shall be used to determine compliance with §115.722(a) - (d) of this title. (5) If an emissions event as defined in §101.1 of this title occurs while HRVOC emissions are being routed to a flare temporarily under this subsection, the owner or operator shall demonstrate compliance with the requirements of §115.722(a) - (d) of this title using process knowledge and engineering calculations in accordance with subsection (g)(2)(E) of this section. (i) For flares specifically designed to receive and control liquid or dual phase streams containing HRVOCs, process knowledge and engineering calculations must be used to determine compliance with the requirements of §115.722(a) - (d) of this title in accordance with subsection (g)(2)(E) of this section. (j) Flares that are used to control vent gases from metal alkyl production processes must comply with the continuous monitoring requirements in subsection (d) of this section, or satisfy the following requirements. (1) The flow rate of the gas routed to the flare, in standard cubic feet per minute, must be determined by complying with the monitoring requirements of subsection (d)(1) of this section, for demonstrating compliance with the site cap and exit velocity requirements in §115.722(a) - (d) of this title, in accordance with subsection (g)(2)(E) of this section. The owner or operator may submit a request to the executive director for alternative operational parameter monitoring in lieu of the flow monitoring specified in this paragraph for situations in which direct flow monitoring is not possible. (2) Process knowledge and engineering calculations may be used to determine net heating value and HRVOC concentrations for demonstrating compliance with §115.722(a) - (d) of this title in accordance with subsection (g)(2)(E) of this section. (k) For flares that are in multi-purpose service (e.g., an emergency flare that is also used to control emissions from emissions events and scheduled startup, shutdown, and maintenance activities), the owner or operator shall: (1) comply with all continuous monitoring requirements in subsection (d) of this section; or (2) comply with the most stringent requirements of each applicable subsection of this section. For the purposes of this paragraph: (A) only flares subject to the monitoring requirements of subsections (e), (f), or (g) of this section can be considered as multi-purpose flares; (B) the requirements of the applicable subsections that shall apply are as follows: (i) for determining minimum net heating value for demonstrating compliance with §115.722(d) of this title, the requirements in subsections (e)(1) or (f)(3) of this section apply; (ii) to determine volumetric flow rate and HRVOC emissions for demonstrating compliance with the exit velocity requirements and the site-wide cap requirements in §115.722(a) - (d) of this title, the following requirements shall apply: Cont'd... |
