Open Loop Heat Pipes for High-Efficiency Desalination Plant

A seawater desalination plant based on open loop heat pipes (OLHPs), coupling with the low pressure steam turbine (LPST) extraction, is presented in this work. The steam extracted from the LPST is a heat source for the sea water evaporation. The sea water circulation is provided by the siphon effect, while the sea water evaporation takes place in the specially designed heat pipes. It can utilize low-grade power plant heat for high-efficiency seawater desalination and realize co-generation of electricity and fresh water without using any additional mechanical equipment. The prototype of the installation is implemented at an existing thermal power plant in Guangdong, China. Results of this study show that the plant can start up quickly and operate stably by using power plant condensation heat. A freshwater production rate of 20.5 L/h can be sustained when working with 55 degrees C heat steam and the value increased to 64.8 L/h with 86 degrees C heat steam. The successful operation of the plant has provided valuable experience for low-grade power plant heat harvesting and an efficient approach for seawater desalination.