Hamworthy Serck Como has commissioned a thermal vapour compression (TVC) seawater desalination plant in Duisburg, Germany with a distillate capacity of 30 tonnes/day. This is the first TVC plant completely engineered and manufactured by Hamworthy Serck Como, and will be used for research purposes.
“The TVC process is one of the most common thermal seawater desalination methods,” said project leader Lena Nendza. “The process’s simplicity saves investment costs compared with thermal plants not utilising TVC. In addition the brine’s maximum temperature can be kept low (
The TVC plant is designed for fully automatic operation and has a touch panel for simple and clear control. The capacity of Hamworthy Serck Como’s standard or individually designed TVC plants ranges between 100 and 3,000 tonnes/day, based on a distillate quality of 10 µS/cm (about 4.0 ppm).
All parts in contact with sea water, brine or vapour are made of corrosion resistant stainless steel or coppernickel. Titanium tubes can be supplied on request. Evaporators can be delivered as packaged units with all integral piping, pumps, valves, switchboard etc. Seasonal changes of sea water temperature are automatically compensated for.
In a TVC horizontal tube evaporator sea water is heated in the end condenser to approximately 42°C - 45°C. Most of it is used just for cooling and returned to the sea. A smaller amount is distributed uniformly in parallel streams and sprayed over horizontal tube bundles.
While flowing downwards from tube row to tube row, the sea water is partially evaporated. The vapour produced is passed through demisters to remove the entrained droplets of water. The vapour from the first effect is condensed inside the tubes of the second effect. The vapour produced in the last effect is divided into two streams. Most of the vapour is re-compressed by a thermal vapour compressor (steam jet ejector). The rest is condensed in the end condenser to remove surplus process heat.
Thermal seawater desalination is an extremely robust evaporation process (compared with membrane methods) that is applied in most large-scale land-based installations in the Gulf region, where power plants and MSF (multi-stage flash) plants are combined as dual-purpose installations for power and water production.
TVC (thermal vapour compression) and MVC (mechanical vapour compression) technology has been developed for small and mid size desalination plants.