Waste water treatment plants division
Itevap
Evaporator for liquid concentration
Due to environmental requirements, the use of evaporators in waste water treatment plants for zero discharge technology and for water recovery with high purity becomes more and more common. Evaporators are also an option for mud concentration in the extrusion die pickling system (see DIE-CLAR catalogue).
ITEVAP evaporators are manufactured in different models ranging from 50 to 13000 liters per day.
The feed of the liquid, the discharge of the distillate and the produced concentrate are carried out automatically. AII functions are PLC managed and programmed and do not need any particular maintenance.
ITEVAP evaporators are manufactured with different types of materials: AISI 316, SANICRO 28, HASTELLOY, TITANIUM HALAR. The ltaltecno technical service will be available when choosing the suitable evaporator model.
ITEVAP evaporator finds application in many water treatment technologies and, in particular, in the DIE-CLAR process (see DIECLAR catalogue).
Phase 3 – Option 2
Mud concentration with vacuum evaporator ITEVAP
When the regeneration and the recovery of the caustic soda is not considered, it is recommendable to concentrate, by means of a vacuum evaporator, the soda solution containing the dissolved aluminium. The sludge produced by this operation must be sent to the waste disposal.
Vacum Evaporator
By taking the liquid contained into the storage tank of the spent caustic soda solution, the concentrator evaporates the main quantity of water contained, which is collected into a storage tank and from here used in the rinsing tank for die rinsing and for the dilution of the solution in the process tank. Once the technically acceptable limit for the machine is achieved, the concentrated sludge is drained into a 3rd tank where it will be sent to waste disposal by means of authorised companies.
Description of the process
ITEVAP is an evaporator which exploits the combined effect of the vacuum technology and heat pump to obtain a distillation at low temperatures. The heat pump, by means of a refrigerating circuit, expands and compresses the “freon” gas which supplies both the calories necessary for the evaporation of the waste and the frigories for the condensation of its distillate.
The heat transfer to the waste occurs by means of a jacket in the bottom of the flash drum, whereas the steam condenses in the heat exchanger. The boiling temperature for aqueous solutions is 35-40°(at a residual pressure of about 4-5 kPa. In the frigorific circuit an air-cooling system dissipates the exceeding heat resulting from the compression work.
The vacuum is generated by an ejector circuit: the distillate, collected from the tank and pumped through the ejector by the pump, generates a depression sufficient to extract both the incondensable gases and the condensed distillate.
For a better efficiency of the ejector, the distillate stored is cooled (ca. 20°C) by means of a cooling coil, a deviation on the main circuit of the heating pump provides the necessary frigories.
The waste feeding and the drain discharge take place through pneumatic valves. A level control placed inside the flash drum regulates the feeding valve, whereas the concentrate’s outlet is regulated by valves and assisted by a membrane pump.
The cycle closes with the return of the refrigerant to the compressor.
Feel free to ask to our commercial department!
service@italtecno.com