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 ------- 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 ------- |