Page 1 of 14

**Subpart V**

**— Nitric Acid Production**  **§98.220 Definition of source category.**  A nitric acid production facility uses one or more trains to produce nitric acid . A nitric acid train produces nitric acid through the catal ytic oxidation of ammonia. **§98.221 Reporting**  **threshold.** You must report GHG emissions under this subpart if your facility contains a nitric acid train and the facility

meets the requirements of either §98.2(a)(1) or (a)(2). **§98.222 GHGs to report.**  (a) You must report N 2 O process emissions from each nitric acid train as required by this subpart. (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 stationary combustion unit by following the requirements of subpart C. **§98.223 Calculating GHG emissions.**  (a) You must determine annual N 2 O process emissions from each nitric acid train according to paragraphs (a)(1) or (a)(2) of this section. (1) Use a site
- specific emission factor and production data according to paragraph s (b) through (i) of this section. (2) Request Administrator approval for an alternative method of determining N2 O emissions according to paragraphs (a)(2)(i) through (a)(2)(i v) of this section. (i ) If you received Administrator approval for an alternative method of determining N 2 O emissions in the previous reporting year and your methodology is unchanged , your alternative method is automatically

approved for the next reporting year.Page 2 of 14

(ii) You must notify

the EPA of your use of a previously approv ed alternative method in yo ur annual report. ( ii i) Otherwise, you must submit the request within 45 day s following promulgation of this subpart or within the first 30 days of each subsequent reporting year. (i v) If the Administrator does not approve your requested alternative method within 150 day s 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 paragraph (a)(1) of this section. (b) You must conduct an annual perform ance test for each nitric acid train according to paragraphs (b)(1) through (3) of this section. (1) You must conduct the performance test at the absorber tail gas vent, referred to as the test point, for each nitric acid train according to §98.224(b) through (f). If multiple nitric acid trains 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 nitric acid trains. (2) You must conduct the performance test under normal process operating conditions. (3) You must measure the production rate during the performance test and calculate the production rate for the test period in tons (100 percent acid basis) per hour. (c) Using the results of the performance test in paragraph (b) of this section, you must calculate an average site
- specific emission factor for each nitric acid train “t” according to Equation V
- 1 of this section:Page 3 of 14

where: EF N2Ot = Average site
- specific N 2 O emissions factor for nitric acid train “t” (lb N 2 O/ton nitric acid produced, 100 percent acid basis). C N2O = N 2 O concentration for each test run during the performance test (ppm N 2 O). 1.14 × 10 −7 = Conversion factor (lb/dscf
- ppm N 2 O). Q = Volumetric flow rate of effluent gas for each test run during the performance test (dscf/hr). P = Production rate for each test run during the performance test (tons nitric acid produced per hour, 100 percent acid basis). n = Number of test runs. (d) If nitric acid train “t” exhausts to any N 2 O abatement technology “N”, you must determine the destruction efficiency for each N 2 O abatement technology “N” according to paragraphs (d)(1), (2), or (3) of this section. (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 results provided the results are sti ll relevant to the current vent stream conditions. You must document how process knowledge (if applicable) was used to determine the destruction efficiency
. (3) Calculate the destruction efficiency by conducting an additional performance test on the emissi ons stream following the N 2 O abatement technology
.Page 4 of 14

(e) If nitric acid train “t” exhausts to any N 2 O abatement technology “N”, you must determine the annual amount of nitric acid produced on nitric acid train “t” while N2 O abatement technology

“N” is operat ing according to §98.224(f). Then you must calculate the abatement utilization factor for each N 2 O abatement technology “N” for each nitric acid train “t” according to Equation V
- 2 of this section.

where: AF t,N = Abatement utilization factor of N 2 O abate ment technology “N” at nitric acid train “t” (fraction of annual production that abatement technology is operating). P t = Total annual nitric acid production from nitric acid train “t” (ton acid produced, 100 percent acid basis). P t,N = Annual nitric acid production from nitric acid train “t” during which N 2 O abatement technology

“N” was operational (ton acid produced, 100 percent acid basis). (f) [Reserved] (g) You must calculate N 2 O emissions for each nitric acid train “t” according to paragraph (g)(1), ( g)(2), (g)(3), or (g)(4) of this section. (1) If nitric acid train “t” exhausts to one N 2 O abatement technology “N” after the test point, you must use the emissions factor (determined in Equation V
- 1 of this section), the destruction efficiency

(determined in paragraph (d) of this section), the annual nitric acid production (determined in paragraph (i) of this section), and the abatement utilization factor (determined in paragraph (e) of this section) according to Equation V
- 3a of this section:Page 5 of 14

where: EN2 Ot = Annual N 2 O mass emissions from nitric acid train “t” according to this Equation V
- 3a (metric tons). EF N2Ot = Average site
- specific N 2 O emissions factor for nitric acid train ”t” (lb N 2 O/ton acid produced, 100 percent acid basis). P t = Annual nitric ac id production from nitric acid train “t” (ton acid produced, 100 percent acid basis). DF = Destruction efficiency of N 2 O abatement technology N that is used on nitric acid train “t” (decimal fraction of N 2 O removed from vent stream). AF = Abatement utilization factor of N 2 O abatement technology “N” for nitric acid train “t” (decimal fraction of annual production during which abatement technology is operating). 2205 = Conversion factor (lb/metric ton). (2) If multiple N 2 O abatement technologies are located in series after your test point, you must use the emissions factor (determined in Equation V
- 1 of this section), the destruction efficiency (determined in paragraph (d) of this section), the annual nitric acid production (determined in paragraph (i) of this section), and the abatement utilization factor (determined in paragraph (e) of this section), according to Equation V
- 3b of this section:

where: EN2Ot = Annual N 2 O mass emissions from nitric acid train “t” according to this Equation V
- 3b (metric tons). EF N2O,t = N 2 O emissions factor for nitric acid train “t” (lb N2 O/ton nitric acid produced).Page 6 of 14

P t = Annual nitric acid produced from nitric acid train “t” (ton acid produced, 100 percent acid basis). DF 1 = Destruction efficiency of N 2 O abatement technology 1 (decimal fraction of N 2 O 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). DF 2 = Destruction efficiency of N 2 O abatement technology 2 (decimal fraction of N 2 O 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). DF N = Destruction efficiency of N 2 O abatement technology N (decimal fraction of N 2 O removed from vent stream). AF N = 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 different N 2 O abatement technologies
. (3) If multiple N 2 O abatement technologies are located in parallel after your test point, yo u must use the emissions factor (determined in Equation V
- 1 of this section), the destruction efficiency (determined in paragraph (d) of this section), the annual nitric acid production (determined in paragraph (i) of this section), and the abatement utilization factor (determined in paragraph (e) of this section), according to Equation V
- 3c of this section:

where:Page 7 of 14

EN2Ot = Annual N 2 O mass emissions from nitric ac id train “t” according to this Equation V
- 3c (metric tons). EF N2O,t = N 2 O emissions factor for nitric acid train “t” (lb N2 O/ton nitric acid produced). P t = Annual nitric acid produced from nitric acid train “t” (ton acid produced, 100 percent acid basis). DF N = Destruction efficiency of N 2 O abatement technology “N” (decimal fraction of N 2 O removed from vent stream). AF N = Abatement utilization factor of N 2 O abatement technology “N” (decimal fraction of time that abatement technology “N” is operating). FC N = Fraction control factor of N 2 O abatement technology “N” (decimal fraction of total emissions from nitric acid train “t” that are sent to abatement technology “N”). 2205 = Conversion factor (lb/metric ton). N = Number of different N 2 O abatement technologies with a fraction control factor. (4) If nitric acid train “t” does not exhaust to any N 2 O abatement technology after the test point, you must use the emissions factor (determined in Equation V
- 1 of this section), and the annual nitric acid prod

uction (determined in paragraph (i) of this section) according to Equation V
- 3b of this section:

where: EN2Ot = Annual N 2 O mass emissions from nitric acid train “t” according to this Equation V
- 3d (metric tons). EF N2Ot = Average site
- specific N 2 O emissio ns factor for nitric acid train ”t” (lb N2 O/ton acid produced, 100 percent acid basis).Page 8 of 14

P t = Annual nitric acid production from nitric acid train “t” (ton acid produced, 100 percent acid basis). 2205 = Conversion factor (lb/metric ton). (h) You must determ ine the annual nitric acid production emissions combined from all nitric acid trains at your facility using Equation V
- 4 of this section:

Where: N 2 O = Annual process N 2 O emissions from nitric acid production facility (metric tons). EN2Ot = N 2 O mass emiss ions per year for nitric acid train “t” (metric tons). m = Number of nitric acid trains. (i) You must determine the total annual amount of nitric acid produced on each nitric acid train “t” (tons acid produced, 100 percent acid basis), according to §98.224 (f). **§98.224 Monitoring and QA/QC requirements.**  (a) You must conduct a new performance test according to a test plan as specified in paragraphs (a)(1) through (3) of this section. (1) Conduct the performance test annuall y. The test should be conducted at a point during the campaign which is representative of the average emissions rate from the nitric acid campaigns. Facilities must document the methods used to determine the representative point of the campaign when the performance test is conducted. (2) Conduct the performance test when your nitric acid production process is changed, specificall y when abatement equipment is installed. (3) If you requested Administrator approval for a n alternative method of determining N 2 O emissions under §98.223(a)(2), you must conduct the performance test if your request hasPage 9 of 14

not been approved b y the Administrator within 150 days of the end of the reporting ye ar 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 at 40 CFR part 63, appendix A, Measurement of Vapor Phase Organic and Inorganic Emissions by Extractive Fourier Transform Infrared (FTIR) Spectroscop y. (2) ASTM D6348
- 03 Standard Test Method for Determination of Gaseous Compounds by Extractive Direct Interface Fourier Transform Infrared (FTIR) Spectroscopy (incorporated by reference in §98.7). (3) An equivalent method, with Administrator approval. (c) You must determine the production rate(s) (100 percent acid basis) from each nitric acid train during the performance test according to paragraphs (c)(1) or (2) of this section. (1) Direct measurement of pro duction and concentration (such as using flow meters, weigh scales, for production and concentration measurements). (2) Existing plant procedures used for accounting purposes (i.e. dedicated tank
- level and acid concentration measurements). (d) You must det ermine 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 associated performance specifications apply. For each test, the facility must prepare an emission factor determination report that must include the items in paragraphs (d)(1) through (d)(3) of this section.Page 10 of 14

(1) Anal ys is of samples, determi nation of emissions, and raw data. (2) All information and data used to derive the emissions factor(s). (3) The production rate during each test and how it was determined. (e) You must determine the total monthly amount of nitric acid produced. You must al so determine the monthly

amount of nitric acid produced while N 2 O abatement technology is operating from each nitric acid train. These monthly amounts are determined according to the methods in paragraphs (c)(1) or (2) of this section. (f) You must determine the annual amount of nitric acid produced. You must also determine the annual amount of nitric acid produced while N2 O abatement technology is operating for each nitric acid train. These annual amounts are determined by summing the respective monthl y ni tric acid quantities determined in paragraph (e) of this section. **§98.225 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 o f 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 section. (a) For each missing value of nitric 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 §98.224 (a) through (d). **§ 98. 226**  **Data reporting requirements.**Page 11 of 14

In addition to the information required b y § 98. 3(c), each annual report must contain the information specified in paragraphs (a) through ( q) of this section. (a) Nitric Acid train identification number. (b) Annual process N 2 O emissions from each nitric acid train (metric tons). (c) [Reserved] (d) Reserved
. (e) Annual nitric acid production from the nitric acid facility (tons, 100 percent acid basis). (f) Number of nitric acid trains. (g) Number of different N 2 O abatement technologies per nitric acid train “t”. (h) Abatement technologies used (if applicable) and date of installation of abatement technology
. (i) Reserved
. (j) Reserved
. (k) T ype of nitric acid process used for each nitric acid train (low, medium, high, or dual pressure). (l) Number of times in the reporting ye ar that missing data procedures were followed to measure nitric acid production (months). (m) If you conducted a performance test and calculated a site
- specific emissions factor according to § 98. 223(a)(1), each annual report must also contain the information specified in paragraphs (m)(1) through (7) of this section. (1) Reserved
. (2) Test meth od used for performance test.Page 12 of 14

(3) Reserved
. (4) Reserved
. (5) Reserved
. (6) Reserved
. (7) Number of times in the reporting ye ar that a performance test had to be repeated (number). (n) If you requested Administrator approval for an alternative method of determining N 2 O emissions under § 98. 223(a)(2), each annual report must also contain the information specified in paragraphs (n)(1) through (4) of this section. (1) Name of alternative method. (2) Description of alternative method. (3) Request date. (4) Approval date. (o) [Reserved] (p) Reserved
. (q) Annual percent N 2 O emission reduction for all nitric acid trains combined. **§ 98. 227**  **Records that must be retained.** In addition to the information required b y § 98. 3(g), you must retain the records specified in paragraphs (a) through (h) of this section for each nitric acid production facility : (a) Records of significant changes to process. (b) Documentation of how process knowledge was used to estimate abatement technology

destruction efficiency

(if applicable). (c) Performance test reports.Page 13 of 14

(d) Number of operating hours in the calendar ye ar for each nitric acid train (hours). (e) Annual nitric acid permitted production capacity (tons). (f) Measurements, records, and calculations used to determine reported parameters. (g) 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 mea surements made with these devices must also be recorded, and the technical basis for these estimates must be provided. (h) Verification software records . You must keep a record of the file generated by the verification software specified in § 98.5(b) for the applicable data specified in paragraphs (h)(1) through (10) of this section. Retention of this file satisfies the recordkeeping requirement for the data in paragraphs (h)(1) through (10) of this section. (1) Annual nitric acid produced from each nitric acid train (tons nitric acid produced, 100% acid basis). (2) Indicate which equation was used to calculate emissions for each nitric acid train. (3) N 2 O concentration per test run during the performance test (ppm N2 O) (Equation V
- 1 of § 98.223 ). (4) Volumetric flow rate of effluent gas per test run during the performance test dscf/hr) (Equation V
- 1). (5) Production rate per test run during the performance test (tons nitric acid produced per hour, 100 percent acid basis) (Equation V
- 1). (6) Annual nitric acid production from each nitric acid train during which each N 2 O abatement technology

was operational (tons nitric acid produced, 100 percent acid basis) (Equation V
- 2 of § 98.223 ).Page 14 of 14

(7) Destruction efficiency of N 2 O abatement technology that is used o n each nitric acid train (decimal fraction of N 2 O removed from vent stream) (Equation V
- 3a of § 98.223 ). (8) Destruction efficiency of each N 2 O abatement technology that is used on each nitric acid train (decimal fraction of N 2 O removed from vent stream) (Equation V
- 3b of § 98.223 ). (9) Destruction efficiency of each N 2 O abatement technology that is used on each nitric acid train (decimal fraction of N 2 O removed from vent stream) (Equation V
- 3c of § 98.223 ). (10) Fraction control factor of each N 2 O abatement technology that is used on each nitric acid train (decimal fraction of total emissions from nitric acid train "t" that are sent to abatement technology

"n")(Equation V
- 3c). **§98.228 Definitions.**  All terms used in this subpart have the same meaning given in the Clean Air Act and subpart A of this part.