Vacuum evaporation equipments are used primarily toseparate
water from liquid waste or aqueous chemicals.
These equipments make possible a dramatic reduction of the
waste volumes for disposal and recycling of the condensed
liquid after the evaporation.
Some of the industrial uses of the vacuum distillationsystem
are
Graphic
arts and textile industry treatment of rinse
waters containing inks, pigments or photopolymers (Napp
process)
Disposal
companies:concentration of exhausted chemicals.
Chemical
tanning, pharmaceutical and cosmetic industry:
concentration of waters coming from process and reactors
cleaning.
Mechanical
Industry: separation of oily exhausted emulsions,
phosphate and degreasing baths as well as tumbling wastes.
Electroplatinq
and gold industry: metals recovery from rinse
waters and concentration of exhausted baths.(pickling,
polishing)
Food
Industry: concentration of retting waters, cleaning
waters.
Photographic:treatment
of exhausted chemicals.
Evaporation
treatments can also be applied for the final concentration
of the liquid wastes coming from ion exchange and membrane
plants.
The Evaporator is a class of heat pump vacuum evaporators
fed with current.
The combined effects of the heatpump and the vacuum allow
to obtain distillation of liquids at low temperature.
The heat pump, by means of a refrigerating circuit, carries
out the expansion and the compression of therefrigerating
fluid R134a and supplies both the calories required for the
evaporation of the waste and the frigoriesnecessary for the
vapor condensation.
The boiling occurs at a temperature of approximately 350C
and at a residual pressure of approximately 6,5 kPa. Vacuum
is created through an ejector.
The energy absorbed by the compressor is transferred to environmentthrough
air and/or water heat exchangers.
The waste is automatically sucked into the boiling chamber
through the opening of a feed pneumatic valve set by afloat
level.
While distillation is taking place, an antifoam is added automatically.
The condensed liquid issues by overflow, from a special tank
where it is kept at a temperature of approximately200C by
means of a refrigerating circuit.
The concentrate. containing the pollutants, is discharged
through atemporized opening of a pneumatic valve when the
correct density is reached.The control of all the operations
is carried out by a PLC.
