North Carolina Administrative Code › Title 15A - Environmental Quality › Chapter 02 - Environmental Management › Subchapter D - AIR POLLUTION CONTROL REQUIREMENTS › Section .0500 - EMISSION CONTROL STANDARDS › Section 02D .0528 - TOTAL REDUCED SULFUR FROM KRAFT PULP MILLS

Current through Register Vol. 39, No. 2, July 15, 2024
(a)
				  For the purpose of this Rule, the following definitions apply:
(1) "Black liquor solids" means the dry
				  weight of the solids that enter the recovery furnace in the black
				  liquor.
(2) "Condensate stripper
				  system" means a column, and associated condensers, used to strip, with air or
				  steam, total reduced sulfur compounds from condensate streams from various
				  processes within a kraft pulp mill.
(3) "Cross recovery furnace" means a furnace
				  used to recover chemicals consisting primarily of sodium and sulfur compounds
				  by burning black liquor which on a quarterly basis contains more than seven
				  percent by weight of the total pulp solids from the neutral sulfite
				  semichemical process and has a green liquor sulfidity of more than 28
				  percent.
(4) "Digester system"
				  means each continuous digester or each batch digester used for the cooking of
				  wood in white liquor and associated flash tanks, blow tanks, chip steamers, and
				  condensers.
(5) "Green liquor
				  sulfidity" means the sulfidity of the liquor that leaves the smelt dissolving
				  tank.
(6) "Kraft pulp mill" means
				  any facility that produces pulp from wood by "cooking", industry term for
				  digesting, wood chips in a water solution of sodium hydroxide and sodium
				  sulfide (white liquor) at high temperature and pressure. Regeneration of
				  cooking chemicals through a recovery process is also considered part of the
				  kraft pulp mill.
(7) "Lime kiln"
				  means a unit used to calcine lime mud that consists primarily of calcium
				  carbonate, into quicklime, which is calcium oxide.
(8) "Multiple-effect evaporator system" means
				  the multiple-effect evaporators and associated condensers and hot wells used to
				  concentrate the spent cooking liquid that is separated from the pulp, known in
				  the industry as "black liquor".
(9)
				  "Neutral sulfite semichemical pulping operation" means any operation in which
				  pulp is produced from wood by "cooking", industry term for digesting, wood
				  chips in a solution of sodium sulfite and sodium bicarbonate, followed by
				  mechanical defibrating, also called grinding the wood pulp, to separate into
				  its fibrous constituents.
(10) "New
				  design recovery furnace" means a straight kraft recovery furnace that has both
				  membrane wall or welded wall construction and emission control designed air
				  systems.
(11) "Old design recovery
				  furnace" means a straight kraft recovery furnace that does not have membrane
				  wall or welded wall construction or emission control designed air
				  systems.
(12) "Recovery furnace"
				  means either a straight kraft recovery furnace or a cross recovery furnace and
				  includes the direct-contact evaporator for a direct-contact furnace.
(13) "Smelt dissolving tank" means a vessel
				  used for dissolving the smelt collected from the recovery furnace.
(14) "Straight kraft recovery furnace" means
				  a furnace used to recover chemicals consisting primarily of sodium and sulfur
				  compounds by burning black liquor which on a quarterly basis contains seven
				  percent by weight or less of the total pulp solids from the neutral sulfite
				  semichemical process or has green liquor sulfidity of 28 percent or
				  less.
(15) "Total reduced sulfur
				  (TRS)" means the sum of the sulfur compounds hydrogen sulfide, methyl
				  mercaptain, dimethyl sulfide, and dimethyl disulfide, that are released during
				  the kraft pulping operation.