Assessment of a new binary geothermal based methanol synthesis plant with power, hydrogen and freshwater

Abstract

The development of an integrated binary geothermal energy production system for the synthesis of green methanol with electricity and freshwater is achieved in this study along with its thermodynamic analysis and assessment through the applications of energy and exergy methodologies. Further to being among the most promising solutions for the future, clean energy sources provide a wide range of energy carriers that may be utilized by communities as well as individuals. Among these energy carriers, hydrogen has attracted considerable attention as a realistic long-term carbon-free energy route. Moreover, methanol and ethanol are proposed as alternative energy carriers synthesized by clean hydrogen. In this regard, the developed system includes a double flash binary geothermal system, an organic Rankine cycle, a multi-effect desalination system, an alkaline electrolyzer, and a methanol synthesis system. In this system, an alkaline electrolyzer is utilized to perform hydrogen production, and then the produced hydrogen is employed for green (clean) methanol production. The performance-related parameters for the overall system and its subsystems are all thermodynamically evaluated with the Engineering Equation Solver software. The developed system utilizes geothermal energy as a renewable energy source and results confirm that the developed system produces a capacity of 0.019 kg/s of green methanol. The parametric studies are further performed to demonstrate the effects of various first flashing pressures on the qualities of steam, mass flow rates of high pressure turbine, and energy and exergy efficiencies. Moreover, the effects of geothermal well temperature on energy and exergy efficiencies are considered. The effects of electrolyzer power usage and general efficiency on the methanol production rate are alsoexamined. The overall energy and exergy efficiencies of the system are determined as 36.96% and 39.31%, respectively.