W. Jehle et al., SEPARATION OF GLYCOL AND WATER FROM COOLANT LIQUIDS BY EVAPORATION, REVERSE-OSMOSIS AND PERVAPORATION, Journal of membrane science, 102, 1995, pp. 9-19
Coolant liquids having glycol contents in the range of 20-30% (p. wt.)
have been identified as hazardous organic waste. According to the tot
al vehicle coolant liquid consumption in the FRG of approximately 200
000 metric tons per year (t/year), less than 40% of these used liquids
are submitted for disposal by methods which are in compliance with en
vironmental legislation, such as incineration. Recently, some waste ma
nagement companies have started pure distillative recovery processes r
esulting in a glycol quality allowing for reuse of the product. For de
watering of the used coolant to a water content of less than 5%, a mem
brane hybrid process has been developed offering some process and econ
omic advantages compared to pure distillative processes. Laboratory- a
nd bench-scale qualification tests have been performed for the differe
nt process components. The lay-out and cost estimations for a plant wi
th a capacity of 12 000 t/year result in investment costs of 4.5-5 mil
lion DM. The operating costs for the recovery process are in the range
of 430 DM/ t of coolant liquid.