[Code of Federal Regulations]
[Title 40, Volume 6]
[Revised as of July 1, 2004]
From the U.S. Government Printing Office via GPO Access
[CITE: 40CFR60.18]
[Page 77-79]
TITLE 40--PROTECTION OF ENVIRONMENT
CHAPTER I--ENVIRONMENTAL PROTECTION AGENCY (CONTINUED)
PART 60_STANDARDS OF PERFORMANCE FOR NEW STATIONARY SOURCES
--Table of Contents
Subpart A_General Provisions
Sec. 60.18 General control device requirements.
(a) Introduction. This section contains requirements for control
devices used to comply with applicable subparts of parts 60 and 61. The
requirements are placed here for administrative convenience and only
apply to facilities covered by subparts referring to this section.
(b) Flares. Paragraphs (c) through (f) apply to flares.
(c)(1) Flares shall be designed for and operated with no visible
emissions as determined by the methods specified in paragraph (f),
except for periods not to exceed a total of 5 minutes during any 2
consecutive hours.
(2) Flares shall be operated with a flame present at all times, as
determined by the methods specified in paragraph (f).
(3) An owner/operator has the choice of adhering to either the heat
content specifications in paragraph (c)(3)(ii) of this section and the
maximum tip velocity specifications in paragraph (c)(4) of this section,
or adhering to the requirements in paragraph (c)(3)(i) of this section.
(i)(A) Flares shall be used that have a diameter of 3 inches or
greater, are nonassisted, have a hydrogen content of 8.0 percent (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=Maximum permitted velocity, m/sec.
K1=Constant, 6.0 volume-percent hydrogen.
K2=Constant, 3.9(m/sec)/volume-percent hydrogen.
XH2=The volume-percent of hydrogen, on a wet basis, as
calculated by using the American Society for Testing and Materials
(ASTM) Method D1946-77. (Incorporated by reference as specified in Sec.
60.17).
(B) The actual exit velocity of a flare shall be determined by the
method specified in paragraph (f)(4) of this section.
(ii) Flares shall be used only with the net heating value of the gas
being combusted being 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 being 7.45 MJ/scm (200 Btu/scf) or greater if the
flare is nonassisted. The net heating value of the gas being combusted
shall be determined by the methods specified in paragraph (f)(3) of this
section.
[[Page 78]]
(4)(i) Steam-assisted and nonassisted flares shall be designed for
and operated with an exit velocity, as determined by the methods
specified in paragraph (f)(4) of this section, less than 18.3 m/sec (60
ft/sec), except as provided in paragraphs (c)(4) (ii) and (iii) of this
section.
(ii) Steam-assisted and nonassisted flares designed for and operated
with an exit velocity, as determined by the methods specified in
paragraph (f)(4), 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).
(iii) Steam-assisted and nonassisted flares designed for and
operated with an exit velocity, as determined by the methods specified
in paragraph (f)(4), less than the velocity, Vmax, as
determined by the method specified in paragraph (f)(5), and less than
122 m/sec (400 ft/sec) are allowed.
(5) Air-assisted flares shall be designed and operated with an exit
velocity less than the velocity, Vmax, as determined by the
method specified in paragraph (f)(6).
(6) Flares used to comply with this section shall be steam-assisted,
air-assisted, or nonassisted.
(d) Owners or operators of flares used to comply with the provisions
of this subpart shall monitor these control devices to ensure that they
are operated and maintained in conformance with their designs.
Applicable subparts will provide provisions stating how owners or
operators of flares shall monitor these control devices.
(e) Flares used to comply with provisions of this subpart shall be
operated at all times when emissions may be vented to them.
(f)(1) Method 22 of appendix A to this part shall be used to
determine the compliance of flares with the visible emission provisions
of this subpart. The observation period is 2 hours and shall be used
according to Method 22.
(2) 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.
(3) The net heating value of the gas being combusted in a flare
shall be calculated using the following equation:
[GRAPHIC] [TIFF OMITTED] TC01JN92.008
where:
HT=Net heating value of the sample, MJ/scm; where the net
enthalpy per mole of offgas is based on combustion at 25 [deg]C and 760
mm Hg, but the standard temperature for determining the volume
corresponding to one mole is 20 [deg]C;
[GRAPHIC] [TIFF OMITTED] TC01JN92.009
Ci=Concentration of sample component i in ppm on a wet basis,
as measured for organics by Reference Method 18 and measured for
hydrogen and carbon monoxide by ASTM D1946-77 or 90 (Reapproved 1994)
(Incorporated by reference as specified in Sec. 60.17); and
Hi=Net heat of combustion of sample component i, kcal/g mole
at 25 [deg]C and 760 mm Hg. The heats of combustion may be determined
using ASTM D2382-76 or 88 or D4809-95 (incorporated by reference as
specified in Sec. 60.17) if published values are not available or
cannot be calculated.
(4) The actual exit velocity of a flare shall be determined by
dividing the volumetric flowrate (in units of standard temperature and
pressure), as determined by Reference Methods 2, 2A, 2C, or 2D as
appropriate; by the unobstructed (free) cross sectional area of the
flare tip.
(5) The maximum permitted velocity, Vmax, for flares
complying with paragraph (c)(4)(iii) shall be determined by the
following equation.
Log10 (Vmax)=(HT+28.8)/31.7
[[Page 79]]
Vmax=Maximum permitted velocity, M/sec
28.8=Constant
31.7=Constant
HT=The net heating value as determined in paragraph (f)(3).
(6) The maximum permitted velocity, Vmax, for air-
assisted flares shall be determined by the following equation.
Vmax=8.706+0.7084 (HT)
Vmax=Maximum permitted velocity, m/sec
8.706=Constant
0.7084=Constant
HT=The net heating value as determined in paragraph (f)(3).
[51 FR 2701, Jan. 21, 1986, as amended at 63 FR 24444, May 4, 1998; 65
FR 61752, Oct. 17, 2000]