Chapter NR 464

NR 464.02(7) (7) “Boiler” means any enclosed combustion device that extracts useful energy in the form of steam. A boiler is not considered a thermal oxidizer.

NR 464.02(8) (8) “Chip steamer” means a vessel used for the purpose of preheating or pretreating wood chips prior to the digester, using flash steam from the digester or live steam.

NR 464.02(9) (9) “Closed-vent system” means a system that is not open to the atmosphere and is composed of piping, ductwork, connections and, if necessary, flow-inducing devices that transport gas or vapor from an emission point to a control device.

NR 464.02(10) (10) “Combustion device” means an individual unit of equipment, including but not limited to, a thermal oxidizer, lime kiln, recovery furnace, process heater or boiler, used for the thermal oxidation of organic hazardous air pollutant vapors.

NR 464.02(11) (11) “Day” means any 24 hour period corresponding to either midnight to midnight or to the actual 24 hour production day used by a specific facility.

NR 464.02(12) (12) “Decker system” means all equipment used to thicken the pulp slurry or reduce its liquid content after the pulp washing system and prior to high-density pulp storage. The decker system includes decker vents, filtrate tanks, associated vacuum pumps, and any other equipment serving the same function as those previously listed.

NR 464.02(13) (13) “Digester system” means each continuous digester or each batch digester used for the chemical treatment of wood or non-wood fibers. The digester system equipment includes associated flash tanks, blow tanks, chip steamers not using live steam, blow heat recovery accumulators, relief gas condensers, prehydrolysis units preceding the pulp washing system, and any other equipment serving the same function as those previously listed. The digester system includes any of the liquid streams or condensates associated with batch or continuous digester relief, blow or flash steam processes.

NR 464.02(14) (14) “Emission point” means any part of a stationary source that emits hazardous air pollutants regulated under this chapter, including emissions from individual process vents, stacks, open pieces of process equipment, equipment leaks, wastewater and condensate collection and treatment system units, and those emissions that could reasonably be conveyed through a stack, chimney or duct where such emissions first reach the environment.

NR 464.02(15) (15) “Evaporator system” means all equipment associated with increasing the solids content or concentrating spent cooking liquor from the pulp washing system including pre-evaporators, multi-effect evaporators, concentrators and vacuum systems, as well as associated condensers, hotwells and condensate streams, and any other equipment serving the same function as those previously listed.

NR 464.02(16) (16) “Flow indicator” means any device that indicates gas or liquid flow in an enclosed system.

NR 464.02(17) (17) “High volume, low concentration collection system” or “HVLC collection system” means the gas collection and transport system used to convey gases from the HVLC system to a control device.

NR 464.02(18) (18) “High volume, low concentration system” or “HVLC system” means the collection of equipment including the pulp washing, knotter, screen, decker and oxygen delignification systems, weak liquor storage tanks and any other equipment serving the same function as those previously listed.

NR 464.02(19) (19) “Knotter system” means equipment where knots, oversized material or pieces of uncooked wood are removed from the pulp slurry after the digester system and prior to the pulp washing system. The knotter system equipment includes the knotter, knot drainer tanks, ancillary tanks and any other equipment serving the same function as those previously listed.

NR 464.02(20) (20) “Kraft pulping” means a chemical pulping process that uses a mixture of sodium hydroxide and sodium sulfide as the cooking liquor.

NR 464.02(21) (21) “Lime kiln” means an enclosed combustion device used to calcine lime mud, which consists primarily of calcium carbonate, into calcium oxide.

NR 464.02(22) (22) “Low volume, high concentration collection system” or “LVHC collection system” means the gas collection and transport system used to convey gases from the LVHC system to a control device.

NR 464.02(23) (23) “Low volume, high concentration system” or “LVHC system” means the collection of equipment including the digester, turpentine recovery, evaporator, steam stripper systems and any other equipment serving the same function as those previously listed.

NR 464.02(24) (24) “Mechanical pulping” means a pulping process that only uses mechanical and thermo-mechanical processes to reduce wood to a fibrous mass. The mechanical pulping processes include, but are not limited to, stone groundwood, pressurized groundwood, refiner mechanical, thermal refiner mechanical, thermo-mechanical and tandem thermo-mechanical.

NR 464.02(25) (25) “Non-wood pulping” means the production of pulp from fiber sources other than trees. The non-wood fiber sources include, but are not limited to, bagasse, cereal straw, cotton, flax straw, hemp, jute, kenaf and leaf fibers.

NR 464.02(26) (26) “Oven-dried pulp” or “ODP” means a pulp sample at zero percent moisture content by weight.

NR 464.02(26)(a) (a) Pulp samples for applicability or compliance determinations for both the pulping and bleaching systems shall be unbleached pulp.

NR 464.02(26)(b) (b) For purposes of complying with mass emission limits in this chapter, megagram of ODP shall be measured to represent the amount of pulp entering and processed by the equipment system under the specified mass limit.

NR 464.02(26)(c) (c) For equipment that does not process pulp, megagram of ODP shall be measured to represent the amount of pulp that was processed to produce the gas and liquid streams.

NR 464.02(27) (27) “Oxygen delignification system” means the equipment that uses oxygen to remove lignin from pulp after high-density stock storage and prior to the bleaching system. The oxygen delignification system equipment includes the blow tank, washers, filtrate tanks, any interstage pulp storage tanks and any other equipment serving the same function as those previously listed.

NR 464.02(28) (28) “Primary fuel” means the fuel that provides the principal heat input to the combustion device. To be considered primary, the fuel must be able to sustain operation of the combustion device without the addition of other fuels.

NR 464.02(29) (29) “Process wastewater treatment system” means a collection of equipment, a process or a specific technique that removes or destroys the HAPs in a process wastewater stream. Examples include, but are not limited to, a steam stripping unit, wastewater thermal oxidizer or biological treatment unit.

NR 464.02(30) (30) “Pulp washing system” means all equipment used to wash pulp and separate spent cooking chemicals following the digester system and prior to the bleaching system, oxygen delignification system or paper machine system at unbleached mills. The pulp washing system equipment includes vacuum drum washers, diffusion washers, rotary pressure washers, horizontal belt filters, intermediate stock chests and their associated vacuum pumps, filtrate tanks, foam breakers or tanks, and any other equipment serving the same function as those previously listed. The pulp washing system does not include deckers, screens, knotters, stock chests or pulp storage tanks following the last stage of pulp washing.

NR 464.02(31) (31) “Pulping line” means a group of equipment arranged in series such that the wood chips are digested and the resulting pulp progresses through a sequence of steps that may include knotting, refining, washing, thickening, blending, storing, oxygen delignification and any other equipment serving the same function as those previously listed.

NR 464.02(32) (32) “Pulping process condensates” means any HAP-containing liquid that results from contact of water with organic compounds in the pulping process. Examples of process condensates include digester system condensates, turpentine recovery system condensates, evaporator system condensates, LVHC system condensates, HVLC system condensates and any other condensates from equipment serving the same function as those previously listed. Liquid streams that are intended for byproduct recovery are not considered process condensate streams.

NR 464.02(33) (33) “Pulping system” means all process equipment, beginning with the digester system, and up to and including the last piece of pulp conditioning equipment prior to the bleaching system, including treatment with ozone, oxygen or peroxide before the first application of a chemical bleaching agent intended to brighten pulp. The pulping system includes pulping process condensates and can include multiple pulping lines.

NR 464.02(34) (34) “Recovery furnace” means an enclosed combustion device where concentrated spent liquor is burned to recover sodium and sulfur, produce steam and dispose of unwanted dissolved wood components in the liquor.

NR 464.02(35) (35) “Screen system” means equipment in which oversized particles are removed from the pulp slurry prior to the bleaching or papermaking system washed stock storage.

NR 464.02(36) (36) “Secondary fiber pulping” means a pulping process that converts a fibrous material, that has previously undergone a manufacturing process, into pulp stock through the addition of water and mechanical energy. The mill then uses that pulp as the raw material in another manufactured product. These mills may also utilize chemical, heat and mechanical processes to remove ink particles from the fiber stock.

NR 464.02(37) (37) “Semi-chemical pulping” means a pulping process that combines both chemical and mechanical pulping processes. The semi-chemical pulping process produces intermediate yields ranging from 55 to 90%.

NR 464.02(38) (38) “Soda pulping” means a chemical pulping process that uses sodium hydroxide as the active chemical in the cooking liquor.

NR 464.02(39) (39) “Spent liquor” means process liquid generated from the separation of cooking liquor from pulp by the pulp washing system containing dissolved organic wood materials and residual cooking compounds.

NR 464.02(40) (40) “Steam stripper system” means a column, including associated stripper feed tanks, condensers or heat exchangers, used to remove compounds from wastewater or condensates using steam. The steam stripper system also contains all equipment associated with a methanol rectification process including rectifiers, condensers, decanters, storage tanks and any other equipment serving the same function as those previously listed.

NR 464.02(41) (41) “Strong liquor storage tanks” means all storage tanks containing liquor that has been concentrated in preparation for combustion or oxidation in the recovery process.

NR 464.02(42) (42) “Sulfite pulping” means a chemical pulping process that uses a mixture of sulfurous acid and bisulfite ion as the cooking liquor.

NR 464.02(43) (43) “Temperature monitoring device” means a piece of equipment used to monitor temperature and having an accuracy of +1.0% of the temperature being monitored expressed in degrees Celsius or +0.5 degrees Celsius (°C), whichever is greater.

NR 464.02(44) (44) “Thermal oxidizer” means an enclosed device that destroys organic compounds by thermal oxidation.

NR 464.02(45) (45) “Turpentine recovery system” means all equipment associated with recovering turpentine from digester system gases including condensers, decanters, storage tanks and any other equipment serving the same function as those previously listed. The turpentine recovery system includes any liquid streams associated with the turpentine recovery process such as turpentine decanter underflow. Liquid streams that are intended for byproduct recovery are not considered turpentine recovery system condensate streams.

NR 464.02(46) (46) “Weak liquor storage tank” means any storage tank except washer filtrate tanks containing spent liquor recovered from the pulping process and prior to the evaporator system.

NR 464.02 History History: CR 00-175: cr. Register March 2002 No. 555, eff. 4-1-02.

NR 464.03 NR 464.03 Standards for the pulping system at kraft, soda and semi-chemical processes.

NR 464.03(1) (1) The owner or operator of each pulping system using the kraft process subject to the requirements of this chapter shall control the total HAP emissions from the following equipment systems, as specified in subs. (3) and (4):

NR 464.03(1)(a) (a) At existing affected sources, the total HAP emissions from the following equipment systems shall be controlled:

NR 464.03(1)(a)1. 1. Each LVHC system.

NR 464.03(1)(a)2. 2. Each knotter or screen system with a total HAP mass emission rate greater than or equal to the rate specified in subd. 2. a. or b. or the combined rate specified in subd. 2. c.:

NR 464.03(1)(a)2.a. a. Each knotter system with emissions of 0.05 kilograms or more of total HAP per megagram of ODP (0.1 pounds per ton).

NR 464.03(1)(a)2.b. b. Each screen system with emissions of 0.10 kilograms or more of total HAP per megagram of ODP (0.2 pounds per ton).

NR 464.03(1)(a)2.c. c. Each knotter and screen system with emissions of 0.15 kilograms or more of total HAP per megagram of ODP (0.3 pounds per ton).

NR 464.03(1)(a)3. 3. Each pulp washing system.

NR 464.03(1)(a)4. 4. Each decker system that does one of the following:

NR 464.03(1)(a)4.a. a. Uses any process water other than fresh water or paper machine white water.

NR 464.03(1)(a)4.b. b. Uses any process water with a total HAP concentration greater than 400 parts per million by weight.

NR 464.03(1)(a)5. 5. Each oxygen delignification system.

NR 464.03(1)(b) (b) At new affected sources, the total HAP emissions from the equipment systems listed in par. (a) 1., 3. and 5. and all of the following equipment systems shall be controlled:

NR 464.03(1)(b)1. 1. Each knotter system.

NR 464.03(1)(b)2. 2. Each screen system.

NR 464.03(1)(b)3. 3. Each decker system.

NR 464.03(1)(b)4. 4. Each weak liquor storage tank.

NR 464.03(2) (2) The owner or operator of each pulping system using a semi-chemical or soda process subject to the requirements of this chapter shall control the total HAP emissions from the following equipment systems, as specified in subs. (3) and (4).

NR 464.03(2)(a) (a) At each existing affected sources, the total HAP emissions from each LVHC system shall be controlled.

NR 464.03(2)(b) (b) At each new affected source, the total HAP emissions from each LVHC system and each pulp washing system shall be controlled.

NR 464.03(3) (3) Equipment systems listed in subs. (1) and (2) shall be enclosed and vented into a closed-vent system and routed to a control device that meets the requirements specified in sub. (4). The enclosures and closed-vent system shall meet the requirements specified in s. NR 464.08.

NR 464.03(4) (4) The control device used to reduce total HAP emissions from each equipment system listed in subs. (1) and (2) shall do one of the following:

NR 464.03(4)(a) (a) Reduce total HAP emissions by 98% or more by weight.

NR 464.03(4)(b) (b) Reduce the total HAP concentration at the outlet of the thermal oxidizer to 20 parts per million or less by volume, corrected to 10% oxygen on a dry basis.

NR 464.03(4)(c) (c) Reduce total HAP emissions using one of the following:

NR 464.03(4)(c)1. 1. A thermal oxidizer designed and operated at a minimum temperature of 871°C (1600 °F) and a minimum residence time of 0.75 seconds.

NR 464.03(4)(c)2. 2. A boiler, lime kiln or recovery furnace by introducing the HAP emission stream with the primary fuel or into the flame zone.

NR 464.03(4)(c)3. 3. A boiler or recovery furnace with a heat input capacity greater than or equal to 44 megawatts (150 million British thermal units per hour) by introducing the HAP emission stream with the combustion air.

NR 464.03(5) (5) Periods of excess emissions reported under s. NR 464.11 are not a violation of subs. (3) and (4) provided that the time of excess emissions, excluding periods of startup, shutdown or malfunction, divided by the total process operating time in a semi-annual reporting period does not exceed any of the following levels:

NR 464.03(5)(a) (a) One percent for control devices used to reduce the total HAP emissions from the LVHC system.

NR 464.03(5)(b) (b) Four percent for control devices used to reduce the total HAP emissions from the HVLC system.

NR 464.03(5)(c) (c) Four percent for control devices used to reduce the total HAP emissions from both the LVHC and HVLC systems.

NR 464.03 History History: CR 00-175: cr. Register March 2002 No. 555, eff. 4-1-02.

NR 464.04 NR 464.04 Standards for the pulping system at sulfite processes.

NR 464.04(1) (1) The owner or operator of each sulfite process subject to the requirements of this chapter shall control the total HAP emissions from the following equipment systems as specified in subs. (2) and (3):

NR 464.04(1)(a) (a) At existing sulfite affected sources, the total HAP emissions from all of the following equipment systems shall be controlled:

NR 464.04(1)(a)1. 1. Each digester system vent.

NR 464.04(1)(a)2. 2. Each evaporator system vent.

NR 464.04(1)(a)3. 3. Each pulp washing system.

NR 464.04(1)(b) (b) At new affected sources, the total HAP emissions from the equipment systems listed in par. (a) and all of the following equipment shall be controlled:

NR 464.04(1)(b)1. 1. Each weak liquor storage tank.

NR 464.04(1)(b)2. 2. Each strong liquor storage tank.

NR 464.04(1)(b)3. 3. Each acid condensate storage tank.

NR 464.04(2) (2) Equipment listed in sub. (1) shall be enclosed and vented into a closed-vent system which routes emissions to a control device that meets the requirements specified in sub. (3). The enclosures and closed-vent system shall meet the requirements specified in s. NR 464.08. Emissions from equipment listed in sub. (1) that do not need to be reduced to meet sub. (3) are not required to be routed to a control device.