Section NR 460.10 - Control device requirements(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)
Wis. Admin. Code Department of Natural Resources NR 460.10
Cr. Register, March, 1997, No. 495, eff. 4-1-97; am. (2) (f), Register, November, 1999, No. 527, eff. 12-1-99; CR 00-175: r. and recr. (2) (f), am. (2) (h) Register March 2002 No. 555, eff. 4-1-02; corrections in (2) (d) and (g) 1. made under s. 13.93(2m) (b) 7, Stats., Register March 2002 No. 555.