United States
Environmental Protection
Agency
Air and Energy Engineering
Research Laboratory
Research Triangle Park, NC 27711
Research and Development
EPA/600/SR-93/161 November 1993
&EPA Project Summary
Initial Assessment of Emissions
from Heat Setting Carpet Yarn
B. McMinn and D. Ocamb
The report gives initial results of a
project to determine the nature of emis-
sions resulting from the heat setting of
carpet yarn and to identify possible con-
trol options. Two Georgia yarn manu-
facturing facilities—World Carpets in
Dalton, GA, a yarn and carpet manu-
facturing facility, and Diamond Mills in
Rome, GA, a yarn spinning facility-
were visited to collect the necessary
technical information to identify the
nature of the heat set emissions and to
suggest possible emission control
strategies. During the visits, informa-
tion on the yarn spinning and heat set-
ting operations was gathered, the
carpet manufacturing process was
viewed, and (with input from the plant
technical staff) opportunities were iden-
tified for preventing and/or controlling
the heat setting emissions.
This Project Summary was developed
by EPA's Air and Energy Engineering
Research Laboratory, Research Triangle
Park, NC, to announce key findings of
the research project that is fully docu-
mented in a separate report of the same
title (see Project Report ordering infor-
mation at back).
Introduction
The face fibers currently used in pro-
cessing carpet yarn include nylon, polypro-
pylene (olefin), polyester, and wool, with
the first three accounting for all but 0.6%
of the face fibers used. These fibers may
be supplied to the yarn plants either as
staple fiber (which must be blended,
carded, drafted, spun, wound, and heat
set) or as bulked continuous filament
(which must be twisted, wound, and heat
set) prior to being shipped to the carpet
manufacturing mills. The output of the car-
pet mills is tufted, knitted, needle punched,
felt, or braided carpet for both contract
and residential markets.
During the production of the fiber and
the processing of the yarn, several chemi-
cals (e.g., finishes and tints) are added TO
increase the fiber processability. It is pos-
sible that the elevated temperatures dur-
ing heat setting in either the Suessen or
Superba systems release these chemi-
cals, resulting in significant visible emis-
sions. Additional potential emitted species
from heat setting operations include steam,
materials used to clean the heat set equip-
ment, and fiber degradation products or
unreacted monomer. At the time of this
report, speciated stack test results identi-
fying the emissions resulting from heat
setting operations were unavailable. How-
ever, industry efforts are currently under-
way to quantify the amount of caprolactam
released from the Suessen heat setting of
nylon 6.
Without specific vent stream character-
istics, it is difficult to accurately assess
heat set emissions and to develop emis-
sion control strategies. However, based
on an initial review of the heat set sys-
tems, only two possible control strategies
appear applicable: condensation and ab-
sorption. Although the installation of a con-
denser would likely control emissions by
nearly 90%, it might also result in fouling
of the exchange media and contamination
(requiring further treatment) of the facility s
wastewater discharge to the publicly
owned treatment works (POTW). Installa-
Printed on Recycled Paper
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tion of an absorber would result in a con-
trol efficiency of 80 to 95%, but it too
would potentially require additional treat-
ment of wastewater discharges. Initial data
suggest that the lowest cost control alter-
native is the absorber.
More information is needed before a
control device can be recommended and
installed. This information would include
details of fiber production and processing,
fiber degradation products and/or residual
unreacted monomer, and applied finishes.
Such information may be available from
fiber manufacturers (particularly those cur-
rently investigating heat setting emissions),
trade associations, heat setting equipment
manufacturers, and local university textile
schools.
B. McMinn and D. Ocamb are with TRC Environmental Corp., Chapel Hill, NC
27514.
Chester A. Vogel is the EPA Project Officer (see below).
The complete report, entitled "Initial Assessment of Emissions from Heat Setting
Carpet Yam," (Order No. PB93-229862; Cost: $ 19.50; subject to change) will be
available only from:
National Technical Information Service
5285 Port Royal Road
Springfield, VA 22161
Telephone: 703-487-4650
The EPA Project Officer can be contacted at:
Air and Energy Engineering Research Laboratory
U.S. Environmental Protection Agency
Research Triangle Park, NC 27711
*U.S. Government Printing Office: 1993 — 550-067/80119
United States
Environmental Protection Agency
Center for Environmental Research Information
Cincinnati, OH 45268
Official Business
Penalty for Private Use
$300
BULK RATE
POSTAGE & FEES PAID
EPA
PERMIT No. G-35
EPA/600/SR-93/161
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