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RE: Recycling ideas for perchloroethylene?

Todd, et al:

Some of my colleagues who've worked with the Air Force on perc reduction for
jet engine maintenance report that aqueous cleaning using power washers is
sufficient for many applications.  In cases where perc is still used, a
vacuum vapor degreaser greatly reduces perc emissions.  Vacuum vapor
degreasers have high capital cost, but you save on solvent use since so
little leaves the apparatus.  Plus, you have the environmental and health
benefits. There's a possibility of using microfiltration to extend the life
of the perc.  Finally, have you looked at the fluid recovery businesses
(e.g., Safety Kleen) for recovery of perc?--I know they recover lots of perc
from dry cleaners and have service contracts with industrial cleaning shops.

There are some other issues to consider.  You mention use of perc in regard
to parts inspection.  Often fluoropenetrant dyes are used to inspect for
cracks.  These dyes typically require organic solvent for removal.  The Air
Force and some airlines have approved alternative dyes that can be easily
removed by aqueous cleaning for nonrotating turbine components.  They still
use the conventional penetrant dyes for rotating hardware inspection--some
airlines have OKed aqueous cleaning to remove this too, though the Air Force
continues to require organic solvent cleaning.  The ability to remove the
dye with aqueous solutions depends on the substrate material--some absorb
penetrant more deeply than others and, so, require stronger cleaning.

I hope this is helpful.


Rodney Sobin						sobin@ctc.com
Concurrent Technologies Corp.			tel. 814-269-6895
1450 Scalp Avenue					fax 814-269-2798
Johnstown, PA 15904				http://www.ctc.com/