How green desalination via SMRs is? A techno-environmental assessment of conceptual designs for MED-TVC and RO hybrid desalination

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Desalination raises concerns about the highly saline brine left after the process and usually disposed of in the sea and oceans. Further, desalination is an energy intensive process and since most of the operational units are powered using conventional fossil fuel, they are continually affecting the environment. The concerns of ecosystem degradation have always restricted the growth of the desalination industry. Due to the strong features of small modular reactors, the SMR-based desalination plants could offer significant improvements in the area of desalination environmental impacts. In this regard, this study investigates the techno-environmental aspects of three state-of-art conceptual MED-RO hybrid desalination systems coupled with a single NuScale SMR power unit to reduce the adverse discharge brine impacts. Hybridization of desalination systems could achieve the comparative advantages of both thermal distillation and membrane desalination aiming to address the socio-economic impacts originating from desalination. For this purpose, several new introduced parameters, including exergetic efficiency, Power-to-Water ratio, specific discharge salinity, intake-seawater-to-brine ratio, discharge stream enthalpy, and net greenhouse gas emissions precluded by using NuScale for different hybrid desalination schemes are assessed. The analysis was completed with the aid of the MATLAB software and THERMOFLEX module using an Excel interface. The main finding of this study is that marine impacts are better justified in hybrid desalination schemes and that further use clean reactor energy source would decrease the environmental burdens. The results show that in case of fully integrated hybrid system 244,000 tons of CO2, 1012 tons of SO2 and 910 tons of NOx could be precluded annually from releasing into the atmosphere. However, hybrid systems generally have more significant marine effects which demonstrates the necessitated further studies and corrective actions.