On or before January 30, 2019, the owner or operator of a flare used as a control device for an emission point subject to this subpart shall meet the applicable requirements for flares as specified in paragraphs (a) through (q) of this section and the applicable requirements in § 63.671 . The owner or operator may elect to comply with the requirements of paragraph (r) of this section in lieu of the requirements in paragraphs (d) through (f) of this section, as applicable.
Where:
Vmax = Maximum allowed flare tip velocity, ft/sec.
NHVvg = Net heating value of flare vent gas, as determined by paragraph (k)(4) of this section, Btu/scf.
1,212 = Constant.
850 = Constant.
Where:
Qvol = Volumetric flow rate, standard cubic feet per second.
Qmass = Mass flow rate, pounds per second.
385.3 = Conversion factor, standard cubic feet per pound-mole.
MWt = Molecular weight of the gas at the flow monitoring location, pounds per pound-mole.
Where:
Vtip = Flare tip velocity, feet per second.
Qcum = Cumulative volumetric flow over 15-minute block average period, standard cubic feet.
Area = Unobstructed area of the flare tip, square feet.
900 = Conversion factor, seconds per 15-minute block average.
Where:
NHVvg = Net heating value of flare vent gas, Btu/scf.
i = Individual component in flare vent gas.
n = Number of components in flare vent gas.
xi = Concentration of component i in flare vent gas, volume fraction.
NHVi = Net heating value of component i according to table 12 of this subpart, Btu/scf. If the component is not specified in table 12 of this subpart, the heats of combustion may be determined using any published values where the net enthalpy per mole of offgas is based on combustion at 25 °C and 1 atmosphere (or constant pressure) with offgas water in the gaseous state, but the standard temperature for determining the volume corresponding to one mole of vent gas is 20 °C.
= NHVmeasured + 938xH2
Where:
NHVvg = Net heating value of flare vent gas, Btu/scf.
NHVmeasured = Net heating value of flare vent gas stream as measured by the continuous net heating value monitoring system, Btu/scf.
xH2 = Concentration of hydrogen in flare vent gas at the time the sample was input into the net heating value monitoring system, volume fraction.
938 = Net correction for the measured heating value of hydrogen (1,212 - 274), Btu/scf.
Where:
NHVcz = Net heating value of combustion zone gas, Btu/scf.
NHVvg = Net heating value of flare vent gas for the 15-minute block period, Btu/scf.
Qvg = Cumulative volumetric flow of flare vent gas during the 15-minute block period, scf.
Qs = Cumulative volumetric flow of total steam during the 15-minute block period, scf.
Qa,premix = Cumulative volumetric flow of premix assist air during the 15-minute block period, scf.
Where:
NHVcz = Net heating value of combustion zone gas, Btu/scf.
NHVvg = Net heating value of flare vent gas for the 15-minute block period, Btu/scf.
Qvg = Cumulative volumetric flow of flare vent gas during the 15-minute block period, scf.
QNG2 = Cumulative volumetric flow of flare supplemental gas during the 15-minute block period, scf.
QNG1 = Cumulative volumetric flow of flare supplemental gas during the previous 15-minute block period, scf. For the first 15-minute block period of an event, use the volumetric flow value for the current 15-minute block period, i.e., QNG1 = QNG2.
NHVNG = Net heating value of flare supplemental gas for the 15-minute block period determined according to the requirements in paragraph (j)(5) of this section, Btu/scf.
Qs = Cumulative volumetric flow of total steam during the 15-minute block period, scf.
Qa,premix = Cumulative volumetric flow of premix assist air during the 15-minute block period, scf.
Where:
NHVdil = Net heating value dilution parameter, Btu/ft2.
NHVvg = Net heating value of flare vent gas determined for the 15-minute block period, Btu/scf.
Qvg = Cumulative volumetric flow of flare vent gas during the 15-minute block period, scf.
Diam = Effective diameter of the unobstructed area of the flare tip for flare vent gas flow, ft. Use the area as determined in paragraph (k)(1) of this section and determine the diameter as
Qs = Cumulative volumetric flow of total steam during the 15-minute block period, scf.
Qa,premix = Cumulative volumetric flow of premix assist air during the 15-minute block period, scf.
Qa,perimeter = Cumulative volumetric flow of perimeter assist air during the 15-minute block period, scf.
Where:
NHVdil = Net heating value dilution parameter, Btu/ft2.
NHVvg = Net heating value of flare vent gas determined for the 15-minute block period, Btu/scf.
Qvg = Cumulative volumetric flow of flare vent gas during the 15-minute block period, scf.
QNG2 = Cumulative volumetric flow of flare supplemental gas during the 15-minute block period, scf.
QNG1 = Cumulative volumetric flow of flare supplemental gas during the previous 15-minute block period, scf. For the first 15-minute block period of an event, use the volumetric flow value for the current 15-minute block period, i.e., QNG1 = QNG2.
NHVNG = Net heating value of flare supplemental gas for the 15-minute block period determined according to the requirements in paragraph (j)(5) of this section, Btu/scf.
Diam = Effective diameter of the unobstructed area of the flare tip for flare vent gas flow, ft. Use the area as determined in paragraph (k)(1) of this section and determine the diameter as
Qs = Cumulative volumetric flow of total steam during the 15-minute block period, scf.
Qa,premix = Cumulative volumetric flow of premix assist air during the 15-minute block period, scf.
Qa,perimeter = Cumulative volumetric flow of perimeter assist air during the 15-minute block period, scf.
40 C.F.R. §63.670