Handbook of Solvents - George Wypych - ChemTech - Ventech!

922 George Wypych
Table 14.9.2. Reported solvent transfers from the metal fabricating and finishing
facilities in 1993 [Data from Ref. 1]
Solvent Amount, kg/year Solvent Amount, kg/year
acetone 767,000 methyl ethyl ketone 5,130,000
n-butyl alcohol 282,000 methyl isobutyl ketone 846,000
sec-butyl alcohol 495 tetrachloroethylene 415,000
cyclohexanone 1,025 toluene 1,935,000
dichloromethane 237,000 1,1,1-trichloroethane 920,000
ethylbenzene 263,000 trichloroethylene 707,000
ethylene glycol 68,000 1,2,4-trimethylbenzene 42,000
2-ethoxy ethanol 1,800 xylene (mixture) 2,335,000
isopropyl alcohol 41,000 m-xylene 27,000
methanol 138,000 o-xylene 37
2-methoxyethanol 7,800 p-xylene 23
trichloroethylene, and methyl isobutyl ketone are transferred in largest quantities outside
industry for treatment and disposal. The metal fabrication and finishing industry’s contribution
to reported releases and transfers in 1995 was 9.3% of the total for 21 analyzed industries.
This industry is the fourth largest contributor to total reported releases and transfers.
Among the potential actions to reduce pollution, these are the most effective: recycling
of solvents, employing better waste control techniques, and substituting raw materials.
For solvent cleaning, several techniques are suggested. Employees should be required
to obtain solvent from their supervisor. It is estimated that this will reduce waste by 49%.
Pre-cleaning (wipe, blow part with air, etc.) should be adopted or the parts should be first
washed with used solvent. Equipment for vapor degreasing should be modified by increasing
its head space, covering degreasing units, installing refrigerator coils, rotating parts before
removing, installing thermostatic controls, and adding filters. Trichloroethylene and
other halogenated solvents should be replaced with liquid aqueous alkali cleaning compounds.
Other waste reduction can be realized by the better production scheduling, use of dry
filters in the spray booth, prevention of leakage from the spray gun, separation of wastes,
and recycling of solvents by distillation.
REFERENCES
1 EPA Office of Compliance Sector Notebook Project. Profile of the Fabricated Metal Products Industry.
US Environmental Protection Agency, 1995.
2 EPA Office of Compliance Sector Notebook Project. Sector Notebook Data Refresh - 1997.
US Environmental Protection Agency, 1998.