Thermodynamic evaluation on the integrated system of VHTR and forward osmosis desalination process Original Research Article

In order to effectively tackle the two global issues, water shortage and energy demand, an integrated system of a very high temperature reactor (VHTR) and forward osmosis (FO) desalination system is proposed. The integration basically implies the coupling of the waste heat from VHTR with the draw solute recovery system of FO seawater desalination system which is the only energy consuming part of the whole FO process. By integrating the two novel technologies, several advantages can be achieved, such as production of fresh water using waste heat and environment protection through waste heat reduction. In order to thermodynamically analyze the integrated system, the FO system and the power conversion systems (PCSs) of VHTR are simulated and integrated using UNISIM program and OLI property package. As a result, the integrated system of FO–VHTR was calculated to have higher Gain Output Ratio (GOR) values ranging from 9.0 to 13.8, than the typical GOR values, ranging from 6 to 12, of multi-stage flash (MSF) and multi-effect distillation (MED). Furthermore, when the technologies were coupled to the same capacity VHTR, the proposed system was calculated to have a significantly higher waste heat utilization rate than the other systems. Accordingly, the water production of the FO–VHTR system was found to be at least 5 times larger than that of the MSF–VHTR system.