Wisconsin Administrative Code › Department of Natural Resources › NR 400-499 - Environmental Protection - Air Pollution Control › Chapter NR 460 - Emission Standards For Hazardous Air Pollutants For Source Categories-General Provisions › Section NR 460.10 - Control device requirements

Current through June 24, 2024
(1) APPLICABILITY.
				This section contains requirements for control devices used to comply with
				provisions in relevant standards. These requirements apply only to affected
				sources covered by relevant standards referring directly or indirectly to this
				section or to
				40 CFR
				63.11.
(2) FLARES.
(a) Owners or operators using flares to
				comply with the provisions of 40 CFR part 63 or chs.
				NR 460 to
				469 shall monitor these control
				devices to assure that they are operated and maintained in conformance with
				their designs. Applicable subparts of 40 CFR part 63 or applicable parts of
				chs.
				NR 460 to
				469 will provide provisions
				stating how owners or operators using flares shall monitor these control
				devices.
(b) Flares shall be
				steam-assisted, air-assisted or non-assisted.
(c) Flares shall be operated at all times
				when emissions may be vented to them.
(d) Flares shall be designed for and operated
				with no visible emissions, except for periods not to exceed a total of 5
				minutes during any 2 consecutive hours. Method 22 in Appendix A of 40 CFR part
				60, incorporated by reference in s.
				NR
				484.04(13), shall be used to
				determine the compliance of flares with the visible emission provisions of 40
				CFR part 63 or chs.
				NR 460 to
				469. The observation period is 2
				hours and shall be used according to Method 22.
(e) Flares shall be operated with a flame
				present at all times. The presence of a flare pilot flame shall be monitored
				using a thermocouple or any other equivalent device to detect the presence of a
				flame.
(f) An owner or operator has
				the choice of adhering to the heat content specifications in subd. 2., and the
				maximum tip velocity specifications in par. (g) or (h), or adhering to the
				requirements in subd. 1.
1.
a. Flares shall be used that have a diameter
				of 3 inches or greater, are nonassisted, have a hydrogen content of 8.0% (by
				volume) or greater, and are designed for and operated with an exit velocity
				less than 37.2 m/sec (122 ft/sec) and less than the velocity Vmax, as
				determined by the following equation:
Vmax = (XH2 - K1) * K2
where:
Vmax is the maximum permitted velocity, m/sec
K1 is the constant, 6.0 volume-percent hydrogen
K2 is the constant, 3.9 (m/sec)/volume-percent
				  hydrogen
XH2 is the volume-percent of hydrogen, on a wet basis, as
				  calculated by using ASTM D1946-90, incorporated by reference in s.
				  NR
				  484.10(28)
b. The actual exit velocity of a flare shall
				be determined by the method specified in par. (g) 1.
2. Flares shall be used only with the net
				heating value of the gas being combusted at 11.2 MJ/scm (300 Btu/scf) or
				greater if the flare is steam-assisted or air-assisted; or with the net heating
				value of the gas being combusted at 7.45 MJ/scm (200 Btu/scf) or greater if the
				flares is non-assisted. The net heating value of the gas being combusted in a
				flare shall be calculated using the following equation:
See PDF
				  for diagram
where:
HT is the net heating value of the sample, MJ/scm; where the
				  net enthalpy per mole of offgas is based on combustion at 25°C and 760 mm
				  Hg, but the standard temperature for determining the volume corresponding to
				  one mole is 20°C
K is a constant
See PDF
				  for diagram
where the standard temperature for (g-mole/scm) is
				  20°C
Ci is the concentration of sample component i in ppmv on a
				  wet basis, as measured for organics by Test Method 18 and measured for hydrogen
				  and carbon monoxide by ASTM D1946-90, incorporated by reference in s.
				  NR
				  484.10(28)
Hi is the net heat of combustion of sample component i,
				  kcal/g-mole at 25°C and 760 mm Hg. The heat of combustion may be determined
				  using ASTM D4809-00, incorporated by reference in s.
				  NR
				  484.10(55), if published values are
				  not available or cannot be calculated
n is the number of sample components
(g)
1. Steam-assisted and nonassisted flares
				shall be designed for and operated with an exit velocity less than 18.3 m/sec
				(60 ft/sec), except as provided in subds. 2. and 3. The actual exit velocity of
				a flare shall be determined by dividing the volumetric flow rate of gas being
				combusted, in units of emission standard temperature and pressure, as
				determined by Method 2, 2A, 2C, or 2D in Appendix A of 40 CFR part 60,
				incorporated by reference in s.
				NR
				484.04(13), as appropriate, by the
				unobstructed (free) cross-sectional area of the flare tip.
2. Steam-assisted and nonassisted flares
				designed for and operated with an exit velocity, as determined by the method
				specified in subd. 1., equal to or greater than 18.3 m/sec (60 ft/sec) but less
				than 122 m/sec (400 ft/sec), are allowed if the net heating value of the gas
				being combusted is greater than 37.3 MJ/scm (1,000 Btu/scf).
3. Steam-assisted and nonassisted flares
				designed for and operated with an exit velocity, as determined by the method
				specified in subd. 1., less than the velocity Vmax, as determined by the method
				specified in this subdivision, but less than 122 m/sec (400 ft/sec) are
				allowed. The maximum permitted velocity, Vmax, for flares complying with this
				subdivision shall be determined by the following equation:
See PDF
				  for diagram
where:
Vmax is the maximum permitted velocity, m/sec
28.8 is a constant
31.7 is a constant
HT is the net heating value as determined in par. (f)
(h) Air-assisted flares
				shall be designed and operated with an exit velocity less than the velocity
				Vmax. The maximum permitted velocity, Vmax, for air-assisted flares shall be
				determined by the following equation:
See PDF
				  for diagram
where:
Vmax is the maximum permitted velocity, m/sec
8.71 is a constant
0.708 is a constant
HT is the net heating value as determined in par.
				  (f)