NR 440.682 HistoryHistory: Cr. Register, September, 1990, No. 417, eff. 10-1-90; am. (4) (b) 3. a., Register, July, 1993, No. 451, eff. 8-1-93; correction in (4) (b) and (d) made under s. 13.93 (2m) (b) 7., Register, November, 1999, No. 527; CR 06-109: am. (3) (f) and (4) (h) 1. and 2. Register May 2008 No. 629, eff. 6-1-08. NR 440.684NR 440.684 Onshore natural gas processing: SO2 emissions. NR 440.684(1)(1) Applicability and designation of affected facilities. NR 440.684(1)(a)(a) The provisions of this section are applicable to the following affected facilities that process natural gas: each sweetening unit, and each sweetening unit followed by a sulfur recovery unit. NR 440.684(1)(b)(b) Facilities that have a design capacity less than 2 long tons per day (LT/D) of hydrogen sulfide (H2S) in the acid gas (expressed as sulfur) are required to comply with sub. (8) (c) but are not required to comply with subs. (3) to (7). NR 440.684(1)(c)(c) The provisions of this section are applicable to facilities located on land and include facilities located onshore which process natural gas produced from either onshore or offshore wells. NR 440.684(1)(d)(d) The provisions of this section apply to each affected facility identified in par. (a) which commences construction or modification after January 20, 1984. NR 440.684(1)(e)(e) The provisions of this section do not apply to sweetening facilities producing acid gas that is completely reinjected into oil-or-gas-bearing geologic strata or that is otherwise not released to the atmosphere. NR 440.684(2)(a)1.1. “Acid gas” means a gas stream of hydrogen sulfide (H2S) and carbon dioxide (CO2) that has been separated from sour natural gas by a sweetening unit. NR 440.684(2)(a)2.2. “Natural gas” means a naturally occurring mixture of a hydrocarbon and nonhydrocarbon gases found in geologic formations beneath the earth’s surface. The principal hydrocarbon constituent is methane. NR 440.684(2)(a)3.3. “Onshore” means all facilities except those that are located in the territorial seas or on the outercontinental shelf. NR 440.684(2)(a)4.4. “Reduced sulfur compounds” means hydrogen sulfide (H2S), carbonyl sulfide (COS), and carbon disulfide (CS2). NR 440.684(2)(a)5.5. “Sulfur production rate” means the rate of liquid sulfur accumulation from the sulfur recovery unit. NR 440.684(2)(a)6.6. “Sulfur recovery unit” means a process device that recovers element sulfur from acid gas. NR 440.684(2)(a)7.7. “Sweetening unit” means a process device that separates the H2S and CO2 contents from the sour natural gas stream. NR 440.684(2)(a)8.8. “Total SO2 equivalents” means the sum of volumetric or mass concentrations of the sulfur compounds obtained by adding the quantity existing as SO2 to the quantity of SO2 that would be obtained if all reduced sulfur compounds were converted to SO2, ppmv or kg/dscm (lb/dscf). NR 440.684(2)(b)(b) As used in this section, all symbols not defined in this subsection have the meanings given them in s. NR 440.03. NR 440.684(2)(b)1.1. “E” is the sulfur emission rate expressed as elemental sulfur in kg/hr (lb/hr), rounded to one decimal place. NR 440.684(2)(b)2.2. “R” is the sulfur emission reduction efficiency achieved in percent carried to one decimal place. NR 440.684(2)(b)3.3. “S” is the sulfur production rate in kg/hr (lb/hr), rounded to one decimal place. NR 440.684(2)(b)4.4. “X” is the sulfur feed rate from the sweetening unit, that is, the H2S in the acid gas, expressed as sulfur, Mg/d (long ton/day), rounded to one decimal place. NR 440.684(2)(b)5.5. “Y” is the sulfur content of the acid gas from the sweetening unit, expressed as mole percent H2S (dry basis) rounded to one decimal place. NR 440.684(2)(b)6.6. “Z” is the minimum required sulfur dioxide (SO2) emission reduction efficiency, expressed as percent carried to one decimal place. Zi refers to the reduction efficiency required at the initial performance test. Zc refers to the reduction efficiency required on a continual basis after compliance with Zi has been demonstrated. NR 440.684(3)(a)(a) During the initial performance test required by s. NR 440.08 (2), each owner or operator shall achieve, at a minimum, an SO2 emission reduction efficiency (Zi) to be determined from Table 1 based on the sulfur feed rate (X) and the sulfur content of the acid gas (Y) of the affected facility. NR 440.684(3)(b)(b) After demonstrating compliance with the provisions of par. (a), the owner or operator shall achieve, at a minimum, an SO2 emission reduction efficiency (Zc) to be determined from Table 2 based on the sulfur feed rate (X) and the sulfur content of the acid gas (Y) of the affected facility.