Handbook of Solvents - George Wypych - ChemTech - Ventech!

1018 George Wypych
Figure 14.22.2. Schematic diagram of emissions from the man-made fiber manufacturing industry. [Reproduced
from EPA Office of Compliance Sector Notebook Project. Profile of the Petroleum Refining Industry. US
Environmental Protection Agency, 1995.]
Tables 14.22.1 and 14.22.2 provide data on releases and transfers from both polymer
manufacturing and man-made fiber production in the USA. Carbon disulfide, methanol,
xylene, and ethylene glycol are used in the largest quantities. Carbon disulfide is used in
manufacture of regenerated cellulose and rayon. Ethylene glycol is used in the manufacture
of polyethylene terephthalate, the manufacture of alkyd resins, and as cosolvent for cellulose
ethers and esters. Methanol is used in several processes, the largest being in the production
of polyester. This industry is the 10th largest contributor of VOC and 7th largest in
releases and transfers.
There have been many initiatives to reduce emissions and usage of solvents.
Man-made fiber manufacturing no longer uses benzene. DuPont eliminated o-xylene and
reduced methanol and ethylene glycol use in its Wilmington operation. This change resulted
in annual savings of $1 million. Process modification in a polymer processing plant
resulted in a decrease in total emissions of 74% and a reduction in the release of
cyclohexane by 96%. Monitoring of thousands of valves in Eastman Texas plant resulted in
a program of valve replacement which eliminated 99% of the emissions. Plant in Florida
eliminated solvents from cleaning and degreasing. These examples show that in many cases
pollution can be reduced by better equipment, organization, and care.