Current through Register Vol. 39, No. 6, September 16, 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.
(b) This Rule shall apply to recovery
furnaces, digester systems, multiple-effect evaporator systems, lime kilns,
smelt dissolving tanks, and condensate stripping systems of kraft pulp mills
not subject to
15A NCAC
02D .0524.
(c) Emissions of total reduced sulfur from
any kraft pulp mill subject to this Rule shall not exceed:
(1) 20 parts per million from any old design
recovery furnace;
(2) five parts
per million from any new design recovery furnace;
(3) 25 parts per million from any cross
recovery furnace;
(4) five parts
per million from any digester system;
(5) five parts per million from any
multiple-effect evaporator system;
(6) 20 parts per million from any lime
kiln;
(7) five parts per million
from any condensate stripping system; and
(8) 0.032 pounds per ton of black liquor
solids (dry weight) from any smelt dissolving tank.
(d) The emission limitations given in
Subparagraphs (c)(1) through (c)(7) of this Rule are measured as hydrogen
sulfide on a dry gas basis and are averages of discrete contiguous 12-hour time
periods. The emission limitations given in Subparagraphs (c)(1) through (c)(3)
of this Rule are corrected to eight percent oxygen by volume. The emission
limitations given in Subparagraph (c)(6) of this Rule is corrected to 10
percent oxygen by volume.
(e) One
percent of all 12-hour total reduced sulfur averages per quarter year in excess
of the limitations given in Subparagraphs (c)(1) through (c)(3) of this Rule,
in the absence of start-ups, shut-downs and malfunctions, shall not be
considered in violation. Two percent of all 12-hour total reduced sulfur
averages per quarter year in excess of the limitation given in Subparagraph
(c)(6) of this Rule, in the absence of start-ups, shut-downs, and malfunctions,
shall not be considered in violation.
