Multi Stage

Features and applications:

The Sondex two-stage freshwater distiller works through the utilization of waste heat and is used where high production is required and there is limited available energy.
It consumes about half the energy of the single stage units.
Typical applications are off-shore rigs, passenger ships, hotels and other places where the waste heat is limited or expensive to create.
The distiller has been specially designed and fully scale tested to ensure excellent performance and reliability with long service intervals and productions of pure freshwater with a low salinity.
The Sondex two-stage distiller covers a capacity range from 50tons/day up to 150tons/day. Therefore we can offer our customers an economical and technical solutions which is superior to any other evaporators on the market.
The Sondex two-stage unit has many remarkable features, it incorporates the specially designed “vertical tube” plates which give excellent water distribution with no disturbing contact points in the boiling stage. This means the water scaling is very low.
The distiller operates fully automatically according given water flow and pressures, and requires a minimum of supervision.
Steam can also be used as the heat source instead of the hot jacket water.

Operation:

The distiller consists of three Sondex titanium plate packs located in two separated chambers working with different vacuums. The upper plate pack – called stage one- evaporates the feed water at 70% vacuum in chamber one. The steam goes through a large diameter pipe down to the second stage where it condenses and releases its energy into the secondary side of the plate pack filled with pre0heated brine obtained from stage one. The pre-heated brine evaporates immediately, as the second stage is working at 90% vacuum in chamber two. The final condenser plate pack, also located in chamber two, is cooled with cold seawater driving the ejector which removes the non-condensable gases and brine from the evaporation process in both stages. Each chamber is equipped with a demister removing water drops and salt from the steam produced in stage one as well as stage two. This results in high quality freshwater coming out from both condensers. The freshwater produced in both stages flows into a “flash tank” ensuring any steam bubbles are removed before entering the freshwater pump, which pumps the water into the storage tanks.