Experimental study on water separation process in a novel spray flash vacuum evaporator with heat-pipe

Based on the high heat transfer performance of heat pipe (HP) and large specific surface area of small diameter droplets, HP and spray technologies are combined in a novel single stage vacuum evaporator and artificial seawater with 3% saltness is studied experimentally. Parametric studies are carried out, such as cold source and heat source temperature, spray temperature, and spray flow. The results show that: the maximum heat flux density reaches 32Wcm−2 on evaporator bland plate; HPs absorb energy effectively from low grade heat source (40–80°C) then transfer the energy to the droplets already flashed, so as to maintain or even increase the superheat degree of droplets during evaporating process; This method can significantly improve the water separation rate (quality of condensed water/quality of dilute solution∗100%); Changing the parameters can regulate water separation from 0% to 65%. Thus it has important significance for utilizing lower grade heat source effectively, gaining brine, and promoting the fresh water yield per unit volume and adaptability to variable load in desalination project. •Desalination is experimentally studied with using heat pipe.•Maximum heat flux of 32W·cm−2 can be achieved.•Water separation rate can significantly improved.•Lower grade heat source (40–80°C) can be significantly used.