Chapter NR 428

NR 428.21(3) (3) Other regulated unit. An emissions unit is exempt from the emission limitations under s. NR 428.22 if it meets all of the following conditions:

NR 428.21(3)(a) (a) The emissions unit does not emit more than 75 tons of NOx per year due to a physical operating constraint or a federally enforceable condition in an air permit.

NR 428.21(3)(b) (b) The emissions unit is located in a facility subject to the applicability thresholds specified under s. NR 428.20 (1) (a) 1., 2. a., or 3. a.

NR 428.21(3)(c) (c) The emissions unit is subject to and meeting an emission limitation under s. NR 428.04 (2) or 428.05 (3).

NR 428.21(3)(d) (d) The emissions unit was constructed prior to August 1, 2007.

NR 428.21 History History: CR 07-016: cr. Register July 2007 No. 619, eff. 8-1-07; CR 21-022: am. (3) (intro.), (a), (b), cr. (3) (c) Register February 2022 No. 794, eff. 3-1-22; correction in (3) (intro.) made under s. 35.17, Stats., Register February 2022 No. 794; CR 23-017: cr. (3) (d) Register March 2024 No. 819, eff. 4-1-24.

NR 428.22 NR 428.22 Emission limitation requirements.

NR 428.22(1) (1) Emission limits. Except as provided under subs. (2) and (3), on or after May 1, 2009, no person may cause, allow, or permit NOX to be emitted in excess of the following emission limitations on a 30-day rolling average basis:

NR 428.22(1)(a) (a) Boilers.

NR 428.22(1)(a)1. 1. For a solid fuel-fired boiler with a maximum heat input capacity equal to or greater than 1,000 mmBtu per hour, one of the following, as applicable:

NR 428.22(1)(a)1.a. a. If tangential, wall, cyclone or fluidized bed-fired, 0.10 pound per mmBtu of heat input.

NR 428.22(1)(a)1.b. b. If arch-fired, 0.18 pound per mmBtu of heat input.

NR 428.22(1)(a)2. 2. For a solid fuel-fired boiler with a maximum heat input capacity equal to or greater than 500 mmBtu per hour and less than 1,000 mmBtu per hour, one of the following, as applicable:

NR 428.22(1)(a)2.a. a. If tangential-fired, 0.15 pound per mmBtu of heat input.

NR 428.22(1)(a)2.b. b. If wall-fired with a heat release rate equal to or greater than 17,000 Btu per cubic feet per hour, 0.17 pound per mmBtu of heat input.

NR 428.22(1)(a)2.c. c. If wall-fired with a heat release rate less than 17,000 Btu per cubic feet per hour, 0.15 pound per mmBtu of heat input.

NR 428.22(1)(a)2.d. d. If cyclone-fired, 0.15 pound per mmBtu of heat input.

NR 428.22(1)(a)2.e. e. If arch-fired, 0.18 pound per mmBtu of heat input.

NR 428.22(1)(a)2.f. f. If fluidized bed-fired, 0.10 pound per mmBtu of heat input.

NR 428.22(1)(a)3. 3. For a solid fuel-fired boiler with a maximum heat input capacity equal to or greater than 250 mmBtu per hour and less than 500 mmBtu per hour, one of the following, as applicable:

NR 428.22(1)(a)3.a. a. If tangential-fired, 0.15 pound per mmBtu of heat input.

NR 428.22(1)(a)3.b. b. If wall-fired with a heat release rate equal to or greater than 17,000 Btu per cubic feet per hour, 0.17 pound per mmBtu of heat input.

NR 428.22(1)(a)3.c. c. If wall-fired with a heat release rate less than 17,000 Btu per cubic feet per hour, 0.15 pound per mmBtu of heat input.

NR 428.22(1)(a)3.d. d. If cyclone-fired, 0.15 pound per mmBtu of heat input.

NR 428.22(1)(a)3.f. f. If arch-fired, 0.18 pound per mmBtu of heat input.

NR 428.22(1)(a)3.g. g. If fluidized bed-fired, 0.10 pound per mmBtu of heat input.

NR 428.22(1)(a)3.h. h. If stoker-fired, 0.20 pound per mmBtu of heat input.

NR 428.22(1)(a)4. 4. For a solid fuel-fired boiler with a maximum heat input capacity equal to or greater than 50 mmBtu per hour and less than 250 mmBtu per hour, one of the following, as applicable:

NR 428.22(1)(a)4.a. a. If tangential-fired, 0.15 pound per mmBtu of heat input.

NR 428.22(1)(a)4.b. b. If wall-fired with a heat release rate equal to or greater than 17,000 Btu per cubic feet per hour, 0.17 pound per mmBtu of heat input.

NR 428.22(1)(a)4.c. c. If wall-fired with a heat release rate less than 17,000 Btu per cubic feet per hour, 0.15 pound per mmBtu of heat input.

NR 428.22(1)(a)4.d. d. If cyclone-fired, 0.15 pound per mmBtu of heat input.

NR 428.22(1)(a)4.e. e. If fluidized bed-fired, 0.10 pound per mmBtu of heat input.

NR 428.22(1)(a)4.f. f. If stoker-fired, 0.25 pound per mmBtu of heat input.

NR 428.22(1)(a)5. 5. For a gaseous fuel-fired boiler with a maximum heat input capacity equal to or greater than 100 mmBtu per hour, 0.08 pound per mmBtu of heat input.

NR 428.22(1)(a)6. 6. For a distillate fuel oil-fired boiler with a maximum heat input capacity equal to or greater than 100 mmBtu per hour, 0.10 pound per mmBtu of heat input.

NR 428.22(1)(a)7. 7. For a residual fuel oil-fired boiler with a maximum heat input capacity equal to or greater than 65 mmBtu per hour, 0.15 pound per mmBtu of heat input.

NR 428.22(1)(b) (b) Lime kilns. For a lime kiln with a maximum heat input capacity equal to or greater than 50 mmBtu per hour, one of the following as applicable:

NR 428.22(1)(b)1. 1. For a gaseous fuel-fired unit, 0.10 pound per mmBtu of heat input.

NR 428.22(1)(b)2. 2. For a distillate oil-fired unit, 0.12 pound per mmBtu of heat input.

NR 428.22(1)(b)3. 3. For a residual oil-fired unit, 0.15 pound per mmBtu of heat input.

NR 428.22(1)(b)4. 4. For a coal-fired unit, 0.60 pound per mmBtu of heat input.

NR 428.22(1)(b)5. 5. For a coke-fired unit, 0.70 pound per mmBtu of heat input.

NR 428.22(1)(c) (c) Reheat, annealing or galvanizing furnaces. For a reheat, annealing or galvanizing furnace with a maximum heat input capacity equal to or greater than 75 mmBtu per hour, 0.08 pounds per million Btu of heat input.

NR 428.22(1)(d) (d) Glass furnaces.

NR 428.22(1)(d)1. 1. For a glass manufacturing furnace with a maximum heat input capacity equal to or greater than 50 mmBtu per hour, 2.0 pounds per ton of produced glass, except as provided in subd. 2.

NR 428.22(1)(d)2. 2. When, on a daily basis, a glass furnace is operated at less than 25% of glass production capacity, the owner or operator shall operate the furnace according to the combustion optimization requirements of s. NR 439.096 and shall meet the monitoring requirements of s. NR 428.05 (2) (e).

NR 428.22(1)(e) (e) Asphalt plants. For an asphalt plant with a maximum heat input capacity equal to or greater than 65 mmBtu per hour, one of the following as applicable:

NR 428.22(1)(e)1. 1. For a gaseous fuel-fired unit, 0.15 pound per million Btu of heat input.

NR 428.22(1)(e)2. 2. For a distillate fuel oil-fired unit, 0.20 pound per million Btu of heat input.

NR 428.22(1)(e)3. 3. For a residual fuel oil-fired or waste oil-fired unit, 0.27 pound per million Btu of heat input.

NR 428.22(1)(f) (f) Process heating. For a process heater, dryer, oven or other process heating device, one of the following as applicable:

NR 428.22(1)(f)1. 1. For a gaseous fuel-fired unit with a maximum heat input capacity equal to or greater than 100 mmBtu per hour, 0.10 pound per mmBtu of heat input.

NR 428.22(1)(f)2. 2. For a distillate oil-fired unit with a maximum heat input capacity equal to or greater than 100 mmBtu per hour, 0.12 pound per mmBtu of heat input.

NR 428.22(1)(f)3. 3. For a residual oil-fired unit with a maximum heat input capacity equal to or greater than 65 mmBtu per hour, 0.18 pound per mmBtu of heat input.

NR 428.22(1)(g) (g) Simple cycle combustion turbines. For a simple cycle combustion turbine, one of the following exhaust outlet concentrations, corrected to 15% O2 and at ambient temperatures greater than 0oF, as applicable:

NR 428.22(1)(g)1. 1. For a unit with a maximum design power output equal to or greater than 50 megawatts, one of the following, as applicable:

NR 428.22(1)(g)1.a. a. If natural gas-fired, 25 parts per million dry volume.

NR 428.22(1)(g)1.b. b. If distillate oil fuel-fired, 65 parts per million dry volume.

NR 428.22(1)(g)1.c. c. If biologically derived gaseous fuel-fired, 35 parts per million dry volume.

NR 428.22(1)(g)2. 2. For a unit with a maximum design power output equal to or greater than 25 megawatts and less than 50 megawatts, one of the following as applicable:

NR 428.22(1)(g)2.a. a. If natural gas-fired, 42 parts per million dry volume.

NR 428.22(1)(g)2.b. b. If distillate oil fuel-fired, 96 parts per million dry volume.

NR 428.22(1)(g)2.c. c. If biologically derived gaseous fuel-fired, 35 parts per million dry volume.

NR 428.22(1)(h) (h) Combined cycle combustion turbines. For a combined cycle combustion turbine, one of the following exhaust outlet concentrations, corrected to 15% O2 and at ambient temperatures greater than 0oF, as applicable:

NR 428.22(1)(h)1. 1. For a natural gas-fired unit with a maximum design power output equal to or greater than 25 megawatts, 9 parts per million dry volume.

NR 428.22(1)(h)2. 2. For a natural gas-fired unit with a maximum design power output equal to or greater than 10 megawatts and less than 25 megawatts, 42 parts per million dry volume.

NR 428.22(1)(h)3. 3. For a distillate oil fuel-fired unit with a maximum design power output equal to or greater than 10 megawatts, 42 parts per million dry volume.

NR 428.22(1)(h)4. 4. For a biologically derived gaseous fuel-fired unit with a maximum design power output equal to or greater than 10 megawatts, 35 parts per million dry volume.

NR 428.22(1)(i) (i) Reciprocating engines. For a reciprocating engine with a maximum design power output equal to or greater than 500 horsepower, one of the following as applicable:

NR 428.22(1)(i)1. 1. For a rich-burn spark ignition unit, 3.0 grams per brake horsepower-hour.

NR 428.22(1)(i)2. 2. For a lean-burn spark ignition unit, 3.0 grams per brake horsepower-hour.

NR 428.22(1)(i)3. 3. For a diesel fuel-fired compression unit, 3.0 grams per brake horsepower-hour.

NR 428.22(1)(i)4. 4. For a dual fuel-fired compression unit, 3.0 grams per brake horsepower-hour.

NR 428.22(2) (2) Electric utility boiler compliance schedule. The owner or operator of an electric utility boiler shall demonstrate compliance with the following interim NOx emission limitations, as applicable, on a 30-day rolling average by May 1, 2009 and with the emission limitations in sub. (1) (a) on and after May 1, 2013:

NR 428.22(2)(a) (a) For a solid fuel-fired boiler with a maximum heat input capacity equal to or greater than 1,000 mmBtu per hour, one of the following, as applicable:

NR 428.22(2)(a)1. 1. If tangential, wall, cyclone or fluidized bed-fired, 0.15 pound per mmBtu of heat input.

NR 428.22(2)(a)2. 2. If arch-fired, 0.18 pound per mmBtu of heat input.

NR 428.22(2)(b) (b) For a solid fuel-fired boiler with a maximum heat input capacity equal to or greater than 500 mmBtu per hour and less than 1,000 mmBtu per hour, one of the following, as applicable:

NR 428.22(2)(b)1. 1. If tangential-fired, 0.15 pound per mmBtu of heat input.

NR 428.22(2)(b)2. 2. If wall-fired, 0.20 pound per mmBtu of heat input.

NR 428.22(2)(b)3. 3. If cyclone-fired, 0.20 pound per mmBtu of heat input.

NR 428.22(2)(b)4. 4. If arch-fired, 0.18 pound per mmBtu of heat input.

NR 428.22(2)(b)5. 5. If fluidized bed-fired, 0.15 pound per mmBtu of heat input.

NR 428.22(3) (3) Emissions units using secondary fuel. An emissions unit that is capable of firing secondary fuel is not subject to the requirements under sub. (1) or (2) when utilizing only a secondary fuel if any of the following apply:

NR 428.22(3)(a) (a) The emissions unit heat input capacity or maximum design power output while utilizing the secondary fuel is less than the applicability thresholds under sub. (1) or (2).

NR 428.22(3)(b) (b) The emissions unit burns the secondary fuel only during any of the following periods:

NR 428.22(3)(b)1. 1. Supply interruption or curtailment of primary fuel. The secondary fuel usage under this subsection may not exceed 500 hours within a 12 consecutive month time period unless the owner or operator obtains a fuel variance under s. NR 436.06.

NR 428.22(3)(b)2. 2. Periodic testing, maintenance, or operator training of the secondary fuel when the periodic testing, maintenance, or operator training does not exceed a combined total of 48 hours during any calendar year.