Working
In the first unit (the evaporator) the liquid to be
evaporated is heated and pumped up in a closed loop to flow down as thin films
along the surface of a number of tilted, perforated plates. The openings of
the special perforations protrude in the flow of liquid and are directed
downflow. This causes a cavitation in the openings through which the gas is
carried along and mixed with the film of liquid as myriads of thin, long
stretched bubbles. The resulting very large gas-liquid contact area causes the
gas to assume the temperature of the liquid and to become saturated with
vapour from it. After demixing the gas goes to the second, identical GALICOS
unit (the condensor) where it cools down and condensates into the cooled film
shaped flows of condensate. Because the gas recirculates in a closed loop
through the two units a continuous distillation process of absorbtion by
evaporation and desorbtion by condensation comes into existence.
Characteristic for this process is that
distillation takes place at atmospheric pressure and with relatively small
differences of temperatures (far) below the boiling point. As a consequence of
this, the phenomenon of scaling on heated surfaces, which is a major problem
with (vacuum) distillation by boiling, is practically non existent. A filmshaped flow of
water is pumped, at raised temperature, over a tilted plate and brought into
intensive contact with a flow of gas or air that passes through a multitude of
perforations that are present in the plate. The intense gas/liquid contact
provides excellent exchange of components and thermal energy and causes the
gas to become fully saturated with vapour at the raised temperature.The gas
then enters an identical, second loope of liquid which is cooled causing the
vapour to condensate.
The system is effective at low temperature
gradients which makes it possible to operate it at almost 100 % thermal
efficiency by reusing the condensation energy for heating purposes. Also the
combining with a heatpump reduces the required thermal energy and
additionally, offers the possibility of fractionating by adjusting (low)
evaporation temperatures.
Advantages
distillate at atmospheric pressure and low temperature.
Not sensitive for fouling.
Low own energy consumption
Easy operation and maintenance
Modular extensable
Capacity
Distillation capacity depending on the conditions of the application (contact Najade)
for information NAJADE separation B.V. Bospad 24, 2374 BT Oud Ade NL.
GALICOS GAs LIquid COntact System
