Calculating GHG emissions.
§ 98.153 Calculating GHG emissions.
(a) The mass of HFC-23 generated from each HCFC-22 production process shall be estimated by using one of two methods, as applicable:
(1) Where the mass flow of the combined stream of HFC-23 and another reaction product (e.g., HCl) is measured, multiply the weekly (or more frequent) HFC-23 concentration measurement (which may be the average of more frequent concentration measurements) by the weekly (or more frequent) mass flow of the combined stream of HFC-23 and the other product. To estimate annual HFC-23 production, sum the weekly (or more frequent) estimates of the quantities of HFC-23 produced over the year. This calculation is summarized in Equation O-1 of this section:
Where:
G23 = Mass of HFC-23 generated annually (metric tons).
c23 = Fraction HFC-23 by weight in HFC-23/other product stream.
Fp = Mass flow of HFC-23/other product stream during the period p (kg).
p = Period over which mass flows and concentrations are measured.
n = Number of concentration and flow measurement periods for the year.
10−3 = Conversion factor from kilograms to metric tons.
(2) Where the mass of only a reaction product other than HFC-23 (either HCFC-22 or HCl) is measured, multiply the ratio of the weekly (or more frequent) measurement of the HFC-23 concentration and the weekly (or more frequent) measurement of the other product concentration by the weekly (or more frequent) mass produced of the other product. To estimate annual HFC-23 production, sum the weekly (or more frequent) estimates of the quantities of HFC-23 produced over the year. This calculation is summarized in Equation O-2 of this section, assuming that the other product is HCFC-22. If the other product is HCl, HCl may be substituted for HCFC-22 in Equations O-2 and O-3 of this section.
Where:
G23 = Mass of HFC-23 generated annually (metric tons).
c23 = Fraction HFC-23 by weight in HCFC-22/HFC-23 stream.
c22 = Fraction HCFC-22 by weight in HCFC-22/HFC-23 stream.
P22 = Mass of HCFC-22 produced over the period p (kg), calculated using Equation O-3 of this section.
p = Period over which masses and concentrations are measured.
n = Number of concentration and mass measurement periods for the year.
10−3 = Conversion factor from kilograms to metric tons.
(b) The mass of HCFC-22 produced over the period p shall be estimated by using Equation O-3 of this section:
Where:
P22 = Mass of HCFC-22 produced over the period p (kg).
O22 = mass of HCFC-22 that is measured coming out of the Production process over the period p (kg).
U22 = Mass of used HCFC-22 that is added to the production process upstream of the output measurement over the period p (kg).
LF = Factor to account for the loss of HCFC-22 upstream of the measurement. The value for LF shall be determined pursuant to § 98.154(e).
(c) For HCFC-22 production facilities that do not use a destruction device or that have a destruction device that is not directly connected to the HCFC-22 production equipment, HFC-23 emissions shall be estimated using Equation O-4 of this section:
Where:
E23 = Mass of HFC-23 emitted annually (metric tons).
G23 = Mass of HFC-23 generated annually (metric tons).
S23 = Mass of HFC-23 sent off site for sale annually (metric tons).
OD23 = Mass of HFC-23 sent off site for destruction (metric tons).
D23 = Mass of HFC-23 destroyed on site (metric tons).
I23 = Increase in HFC-23 inventory = HFC-23 in storage at end of year - HFC-23 in storage at beginning of year (metric tons).
(d) For HCFC-22 production facilities that use a destruction device connected to the HCFC-22 production equipment, HFC-23 emissions shall be estimated using Equation O-5 of this section:
Where:
E23 = Mass of HFC-23 emitted annually (metric tons).
EL = Mass of HFC-23 emitted annually from equipment leaks, calculated using Equation O-6 of this section (metric tons).
EPV = Mass of HFC-23 emitted annually from process vents, calculated using Equation O-7 of this section (metric tons).
ED = Mass of HFC-23 emitted annually from destruction device (metric tons), calculated using Equation O-8 of this section.
(1) The mass of HFC-23 emitted annually from equipment leaks (for use in Equation O-5 of this section) shall be estimated by using Equation O-6 of this section:
Where:
EL = Mass of HFC-23 emitted annually from equipment leaks (metric tons).
c23 = Fraction HFC-23 by weight in the stream(s) in the equipment.
FGt = The applicable leak rate specified in Table O-1 of this subpart for each source of equipment type and service t with a screening value greater than or equal to 10,000 ppmv (kg/hr/source).
NGt = The number of sources of equipment type and service t with screening values greater than or equal to 10,000 ppmv as determined according to § 98.154(i).
FLt = The applicable leak rate specified in Table O-1 of this subpart for each source of equipment type and service t with a screening value of less than 10,000 ppmv (kg/hr/source).
NLt = The number of sources of equipment type and service t with screening values less than 10,000 ppmv as determined according to § 98.154(j).
p = One hour.
n = Number of hours during the year during which equipment contained HFC-23.
t = Equipment type and service as specified in Table O-1 of this subpart.
10−3 = Factor converting kg to metric tons.
(2) The mass of HFC-23 emitted annually from process vents (for use in Equation O-5 of this section) shall be estimated by using Equation O-7 of this section:
Where:
EPV = Mass of HFC-23 emitted annually from process vents (metric tons).
ERT = The HFC-23 emission rate from the process vents during the period of the most recent test (kg/hr).
PRp = The HCFC-22 production rate during the period p (kg/hr).
PRT = The HCFC-22 production rate during the most recent test period (kg/hr).
lp = The length of the period p (hours).
10−3 = Factor converting kg to metric tons.
n = The number of periods in a year.
(3) The total mass of HFC-23 emitted from destruction devices shall be estimated by using Equation O-8 of this section:
Where:
ED = Mass of HFC-23 emitted annually from the destruction device (metric tons).
FD = Mass of HFC-23 fed into the destruction device annually (metric tons).
D23 = Mass of HFC-23 destroyed annually (metric tons).
(4) For facilities that destroy HFC-23, the total mass of HFC-23 destroyed shall be estimated by using Equation O-9 of this section:
Where:
D23. = Mass of HFC-23 destroyed annually (metric tons).
FD = Mass of HFC-23 fed into the destruction device annually (metric tons).
DE = Destruction Efficiency of the destruction device (fraction).
[74 FR 56374, Oct. 30, 2009, as amended at 78 FR 71955, Nov. 29, 2013]
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