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**Subpart E —** 

**Adipic Acid Production** § 98.50 Definition of source category. The adipic acid production source category consists of all adipic acid production facilities that use oxidation to produce adipic acid. § 98.51 Reporting threshold. You must report GHG emissions under this subpart if your facility contains an adipic acid production process and the facility meets the requirements of either §98.2(a)(1) or (2). § 98.52 GHGs to report. (a) You must report N 2 O process emissions at the facility level. (b) You must report under subpart C of this part (General Stationary Fuel Combustion Sources) the emissions of CO 2 , CH 4 , and N 2 O from each stati onary combustion unit following the requirements of subpart C. § 98.53 Calculating GHG emissions. (a) You must determine annual N 2 O emissions from adipic acid production according to paragraphs (a)(1) or (2) of this section. (1) Use a site
- specific emission factor and production data according to paragraphs (b) through (i) of this section.Page 2 of 16

(2) Request Administrator approval for an alternative method of determining N 2 O emissions according to paragraphs (a)(2)(i) and (ii) of this section. (i) You must submit the request within 45 days following promulgation of this subpart or within the first 30 days of each subsequent reporting year. (ii) If the Administrator does not approve your requested alternative method within 150 days of the end of the reporting year, you must determine the N 2 O emissions for the current reporting period using the procedures specified in paragraphs (b) through (h) of this section. (b) You must conduct an annual performance test according to paragraphs (b)(1) through (3) of this section. (1) You must conduct the test on the vent stream from the nitric acid oxidation step of the process, referred to as the test point, according to the methods specified in §98.54(b) through (f). If multiple adipic acid production units exhaust to a common abatement technology and/or emission point, you must sample each process in the ducts before the emissions are combined, sample each process when only one process is operating, or sample the combined emissions when multiple processes are operating and base the site
- specific emission factor on the combined production rate of the multiple adipic acid production units.Page 3 of 16

(2) You must conduct the performance test under normal process operating conditions. (3) You must measure the adipic acid production rate during the test and calculate the production rate for the test period in tons per hour. (c) Using the results of the performance test in paragraph (b) of this section, you must calculate an emission factor for each adipic acid unit according to Equation E

– 1 of this section:

Where:
EFN2 O,z = Average facility
- specific N 2O emission factor for each adipic acid production unit “z” (lb N 2O/ton adipic acid produced). CN2 O = N 2O concentration per test run during the

performance test (ppm N 2O). 1.14 × 10 −7 = Conversion factor (lb/dscf

-ppm N 2O). Q = Volumetric flow rate of effluent gas per test

run during the performance test (dscf/hr). P = Production rate per test run during the

performance test (tons adipic acid produced/hr).
n = Number of test runs. (d) If the adipic acid production unit exhausts to any N 2O abatement technology “N ” , you must determine the destruction efficiency according to paragraphs (d)(1), (d) (2), or (d) (3) of this section.Page 4 of 16

(1) Use the manufacturer's specified destruction efficiency. (2) Estimate the destruction efficiency through process knowledge. Examples of information that could constitute process knowledge include calculations based on material balances, process stoichiometry, or previous test re sults provided the results are still relevant to the current vent stream conditions. You must document how process knowledge was used to determine the destruction efficiency. (3) Calculate the destruction efficiency by conducting an additional performance test on the vent stream following the N 2O abatement technology. (e) If the adipic acid production unit exhausts to any N2O abatement technology “N ”, you must determine the annual amount of adipic acid produced while N 2 O abatement technology “N” is operating according to §98.54(f). Then you must calculate the abatement factor for N 2O abatement technology “N” according to Equation E

– 2 of this section.

Where:
AFN = Abatement utilization factor of N 2 O abatement

technology “N” (fraction of annual production that abatement technology is operating).Page 5 of 16

P z,N = Annual adipic acid production during which N 2O

abatement technology “N” was used on unit “z” (ton adipic acid produced). P z = Total annual adipic acid production from unit

“ z” (ton acid produced). (f) You must determine the annual amount of adipic acid produced according to §98.54(f). (g) You must calculate N 2 O emissions according to paragraph (g)(1), (2), (3), or (4) of this section for each adipic acid production unit. (1) If one N 2O abatement technology “N” is located after your test point, you must use the emissions factor (determined in Equation E

– 1 of this section), the destruction efficiency (determined in paragraph (d) of this section), the annual adipic acid productio n (determined in paragraph (f) of this section), and the abatement utilization factor (determined in paragraph (e) of this section), according to Equation E

– 3a of this section:

Where:
E a,z = Annual N 2 O mass emissions from adipic acid

production unit “z” according to this Equation E

– 3a (metric tons). EFN2 Oz = N 2O emissions factor for unit “z” (lb N 2O/ton

adipic acid produced). P z = Annual adipic acid produced from unit “z”

(tons).Page 6 of 16

DF = Destruction efficiency of N 2O abatement

technology “N” ( decimal fraction of N 2O removed from vent stream). AF = Abatement utilization factor of N 2 O abatement

technology “N” ( decimal fraction of time that the abatement technology is operating). 2205 = Conversion factor (lb/metric ton). (2) If multiple N 2O abateme nt technologies are located in series after your test point, you must use the emissions factor (determined in Equation E

– 1 of this section), the destruction efficiency (determined in paragraph (d) of this section), the annual adipic acid production (determ ined in paragraph (f) of this section), and the abatement utilization factor (determined in paragraph (e) of this section), according to Equation E

– 3b of this section:

Where:
E b,z = Annual N 2 O mass emissions from adipic acid

production unit “z” according to this Equation E

– 3b (metric tons). EFN2 O,z = N 2O emissions factor for unit “z” (lb N 2O/ton

adipic acid produced). P z = Annual adipic acid produced from unit “z”

(tons). DF 1 = Destruction efficiency of N 2O abatement

technology 1 ( decimal fraction of N 2O removed from vent stream). AF 1 = Abatement utilization factor of N 2 O abatement

technology 1 ( decimal fraction of time that abatement technology 1 is operating).Page 7 of 16

DF 2 = Destruction efficiency of N 2O abatement

technology 2 ( decimal fracti on of N 2O removed from vent stream). AF 2 = Abatement utilization factor of N 2 O abatement

technology 2 ( decimal fraction of time that abatement technology 2 is operating). DFN = Destruction efficiency of N 2O abatement

technology “ N ” ( decimal fraction of N 2O removed from vent stream). AFN = Abatement utilization factor of N 2 O abatement

technology “ N ” ( decimal fraction of time that abatement technology N is operating). 2205 = Conversion factor (lb/metric ton). N = Number of diff erent N 2 O abatement technologies. (3) If multiple N 2O abatement technologies are located in parallel after your test point, you must use the emissions factor (determined in Equation E

– 1 of this section), the destruction efficiency (determined in paragraph (d) of this section), the annual adipic acid production (determined in paragraph (f) of this section), and the abatement utilization factor (determined in paragraph (e) of this section), according to Equation E

– 3c of this section:

Where:
E c,z = Annual N 2 O mass emissions from adipic acid

production unit “z” according to this Equation E

– 3c (metric tons). EFN2 O,z = N 2O emissions factor for unit “z” (lb N 2O/ton

adipic acid produced). P z = Annual adipic acid produced from unit “z”

(tons).Page 8 of 16

DFN = Destruction eff iciency of N 2O abatement

technology “N” ( decimal fraction of N 2O removed from vent stream). AFN = Abatement utilization factor of N 2 O abatement

technology “N” ( decimal fraction of time that the abatement technology is operating). FCN = Fracti on control factor of N 2 O abatement

technology “N” ( decimal fraction of total emissions from unit “z” that are sent to abatement technology “N”). 2205 = Conversion factor (lb/metric ton). N = Number of different N 2 O abatement technologies

with a frac tion control factor. (4) If no N 2O abatement technologies are located after your test point, you must use the emissions factor (determined using Equation E

– 1 of this section) and the annual adipic acid production (determined in paragraph (f) of this section) according to Equation E

– 3d of this section for each adipic acid production unit.

Where:
E d,z = Annual N 2 O mass emissions from adipic acid

production for unit “z” according to this Equation E

– 3d (metric tons). EFN2 O = N 2O emissions factor for unit “z” (lb N 2O/ton

adipic acid produced). P Z = Annual adipic acid produced from unit “z”

(tons). 2205 = Conversion factor (lb/metric ton).Page 9 of 16

(h) You must determine the emissions for the facility by summing the unit level emissions according to Equation E

– 4 of this section.

Where:
E a,z = Annual N 2 O mass emissions from adipic acid

production unit “z” according to Equation E

– 3a of this section (metric tons). E b,z = Annual N 2 O mass emissions from adipic acid

production unit “z” according to Equation E

– 3b of this section (metric tons). E c,z = Annual N 2 O mass emissions from adipic acid

production unit “z” according to Equation E

– 3c of this section (metric tons). E d,z = Annual N 2 O mass emissions from adipic acid

production unit “z” according to Equation E

– 3d of this section (metric tons). M = Total number of adipic acid production units. (i) You must determine the amount of process N 2 O emissions that is sold or transferred off site (if applicable). You can determine the amount using existing process flow meters and N 2O analyzers. § 98.54 Monitoring and QA/QC requirements. (a) You must conduct a new performance test and calculate a new emissions factor for each adipic acid production unit according to the frequency specified in paragraphs (a)(1) through (3) of this section.Page 10 of 16

(1) Conduct the performance test annually. The test must be conducted at a point during production that is representative of the average emissions rate from your process. You must document the methods used to determine the representative point. (2) Conduct the performance test when your adipic acid production process is changed either by altering the ratio of cyclohexanone to cyclohexanol or by installing abatement equipment. (3) If you requested Administrator approval for an alternative method of determining N 2 O emissions under §98.53(a)(2), you must conduct the performance test if your request has not been approved by the Administrator within 150 days of the end of the reporting year in which it was submitted. (b) You must measure the N 2 O concentration during the performance test using one of the methods in paragraphs (b)(1 ) through (b)(3) of this section. (1) EPA Method 320, Measurement of Vapor Phase Organic and Inorganic Emissions by Extractive Fourier Transform Infrared (FTIR) Spectroscopy in 40 CFR part 63, Appendix A; (2) ASTM D6348

– 03 Standard Test Method for Determin ation of Gaseous Compounds by Extractive Direct Interface Fourier Transform Infrared (FTIR) Spectroscopy (incorporated by reference, see §98.7); or (3) An equivalent method, with Administrator approval.Page 11 of 16

(c) You must determine the adipic acid production rat e during the performance test according to paragraph (c)(1) or (c)(2) of this section. (1) Direct measurement (such as using flow meters or weigh scales). (2) Existing plant procedures used for accounting purposes. (d) You must determine the volumetric flow rate during the performance test in conjunction with the applicable EPA methods in 40 CFR part 60, appendices A

– 1 through A

– 4. Conduct three emissions test runs of 1 hour each. All QA/QC procedures specified in the reference test methods and any associat ed performance specifications apply. For each test, the facility must prepare an emissions factor determination report that must include the items in paragraphs (d)(1) through (d)(3) of this section: (1) Analysis of samples, determination of emissions, and raw data. (2) All information and data used to derive the emissions factor. (3) The production rate(s) during the performance test and how each production rate was determined. (e) You must determine the monthly amount of adipic acid produced. You must als o determine the monthly amount of adipic acid produced during which N 2 O abatement technology is operating.Page 12 of 16

These monthly amounts are determined according to the methods in paragraphs (c)(1) or ( c) ( 2) of this section. (f) You must determine the annual amount of adipic acid produced. You must also determine the annual amount of adipic acid produced during which N 2 O abatement technology is operating. These are determined by summing the respective monthly adipic acid production quantities determined in paragraph (e) of this section. § 98.55 Procedures for estimating missing data. A complete record of all measured parameters used in the GHG emissions calculations is required. Therefore, whenever a quality
- assured value of a required parameter is unavailable, a substitute data value for the missing parameter shall be used in the calculations as specified in paragraphs (a) and (b) of this sect ion. (a) For each missing value of monthly adipic acid production, the substitute data shall be the best available estimate based on all available process data or data used for accounting purposes (such as sales records). (b) For missing values related to the performance test, including emission factors, production rate, and N 2 O concentration, you must conduct a new performance test according to the procedures in §98.54 (a) through (d). § 98.56 Data reporting requirements.Page 13 of 16

In addition to the information required by §98.3(c), each annual report must contain the information specified in paragraphs (a) through (l) of this section at the facility level. (a) Annual process N 2 O emissions from adipic acid production (metric tons). (b) Annual adipic acid production (tons). (c) Annual adipic acid production during which N 2 O abatement technology (located after the test point) is operating (tons). (d) Annual process N 2 O emissions from adipic acid production facility that is sold or transferred off site (metric tons). (e ) Number of abatement technologies (if applicable). (f) Types of abatement technologies used (if applicable). (g) Abatement technology destruction efficiency for each abatement technology (percent destruction). (h) Abatement utilization factor for each abatement technology (fraction of annual production that abatement technology is operating). (i) Number of times in the reporting year that missing data procedures were followed to measure adipic acid production (months). (j) If you conducted a performance test and calculated a site
- specific emissions factor according to §98.53(a)(1), each annual report must also contain the information specified inPage 14 of 16

paragraphs (j)(1) through (7) of this section for each adipic acid production unit. (1) Emission factor (lb N 2 O/ton adipic acid). (2) Test method used for performance test. (3) Production rate per test run during performance test (tons/hr). (4) N 2 O concentration per test run during performance test (ppm N 2 O). (5) Volumetric flow rate per test run during performan ce test (dscf/hr). (6) Number of test runs. (7) Number of times in the reporting year that a performance test had to be repeated (number). (k) If you requested Administrator approval for an alternative method of determining N 2 O emissions under §98.53(a)(2) , each annual report must also contain the information specified in paragraphs (k)(1) through (4) of this section for each adipic acid production facility. (1) Name of alternative method. (2) Description of alternative method. (3) Request date. (4) Approva l date.Page 15 of 16

(l) Fraction control factor for each abatement technology (percent of total emissions from the production unit that are sent to the abatement technology) if equation E

– 3c is used. § 98.57 Records that must be retained. In addition to the information required by §98.3(g), you must retain the records specified in paragraphs (a) through (h) of this section at the facility level: (a) Annual adipic acid production capacity (tons). (b) Records of significant changes to process. (c) Number of facility and unit operating hours in calendar year. (d) Documentation of how accounting procedures were used to estimate production rate. (e) Documentation of how process knowledge was used to estimate abatement technology destruction efficiency. (f) Performance test reports. (g) Measurements, records and calculations used to determine reported parameters. (h) Documentation of the procedures used to ensure the accuracy of the measurements of all reported parameters, including but not limited to, calibration of weighing equipment, flow meters, and other measurement devices. The estimated accuracy of measurements made with these devices must also bePage 16 of 16

recorded, and the technical basis for these estimates must be provided. § 98.58 Definitions. All terms used in this subpart have the same meaning given in the Clean Air Act and subpart A of this part.