Current through Register Vol. 39, No. 6, September 16, 2024
(a) For the purpose of this Rule, the
following definitions shall apply:
(1)
"By-product and diluent recovery operation" means the process that separates
the diluent from the by-product (atactic) and purifies and dries the diluent
for recycle.
(2) "Continuous mixer"
means the process that mixes polymer with anti-oxidants.
(3) "Decanter" means the process that
separates the diluent/crude product slurry from the alcohol-water solution by
decantation.
(4) "Ethylene recycle
treater" means the process that removes water and other impurities from the
recovered ethylene.
(5)
"High-density polyethylene plants using liquid phase slurry processes" means
plants that produce high-density polyethylene in which the product,
polyethylene, is carried as a slurry in a continuous stream of process diluent,
usually pentane or isobutane.
(6)
"Neutralizer" means the process that removes catalyst residue from the
diluent/crude product slurry.
(7)
"Polypropylene plants using liquid phase process" means plants that produce
polypropylene in which the product, polypropylene, is carried as a slurry in a
continuous stream of process diluent, usually hexane.
(8) "Polystyrene plants using continuous
processes" means plants that produce polystyrene in which the product,
polystyrene, is transferred in a continuous stream in a molten state.
(9) "Product devolatilizer system" means the
process that separates unreacted styrene monomer and by products from the
polymer melt.
(10) "Reactor" means
the process in which the polymerization takes place.
(b) This Rule applies to:
(1) polypropylene plants using liquid phase
processes;
(2) high-density
polyethylene plants using liquid phase slurry processes; and
(3) polystyrene plants using continuous
processes.
(c) For
polypropylene plants subject to this Rule, the emissions of volatile organic
compounds shall be reduced by 98 percent by weight or to 20 ppm, whichever is
less stringent, from:
(1) reactor
vents;
(2) decanter
vents;
(3) neutralizer
vents;
(4) by-product and diluent
recovery operation vents;
(5) dryer
vents; and
(6) extrusion and
pelletizing vents.
(d)
For high-density polyethylene plants subject to this Rule, the emissions of
volatile organic compounds shall be reduced by 98 percent by weight or to 20
ppm, whichever is less stringent, from:
(1)
ethylene recycle treater vents;
(2)
dryer vents; and
(3) continuous
mixer vents.
(e) For
polystyrene plants subject to this Rule, the emissions of volatile organic
compounds shall not exceed 0.24 pounds per ton of product from the product
devolatilizer system.
(f) If flares
are used to comply with this Rule, all of the following conditions shall be
met:
(1) visible emissions shall not exceed
five minutes in any two-hour period;
(2) a flame in the flare shall be
present;
(3) if the flame is
steam-assisted or air-assisted, the net heating value shall be at least 300 Btu
per standard cubic foot. If the flame is non-assisted, the net heating value
shall be at least 200 Btu per standard cubic foot; and
(4) if the flare is steam-assisted or
non-assisted, the exit velocity shall be no more than 60 feet per second. If
the flare is air-assisted, the exit velocity shall be no more than (8.706 +
0.7084 HT) feet per second, where HT is the net heating value.
A flare that meets the conditions given in Subparagraphs
(1) through (4) of this Paragraph are presumed to achieve 98 percent
destruction of volatile organic compounds by weight. If the owner or operator
of the source chooses to use a flare that fails to meet one or more of these
conditions, he or she shall demonstrate to the Director that the flare shall
destroy at least 98 percent of the volatile organic compounds by weight. To
determine if the specifications for the flare are being met, the owner or
operator of a source using the flare to control volatile organic compound
emissions shall install, operate, and maintain necessary monitoring instruments
and shall keep records as required by
15A NCAC
02D .0903.
Authority
G.S.
143-215.3(a)(1);
143-215.107(a)(5);
Eff. May 1, 1985;
Readopted Eff. November 1, 2020;
Amended Eff. October 1, 2022.
