Hydrogen Production Using Proposed Cycle from Sabalan Geothermal Wells via Proton Exchange Membrane Electrolysis

In the present study, a new combined cycle (including a two-step flash evaporation, the Kalina cycle, and a proton-exchange membrane) for simultaneous power and hydrogen generation from Sabalan geothermal wells has been proposed and analyzed from the viewpoints of energy and exergy. The effects of important parameters including separators pressure of flash evaporation, the minimum temperature difference in the pinch point, Kalian higher pressure, superheated geothermal fluid, the ratio of consumed power for hydrogen production and dead state temperature on the amount of produced hydrogen, the net generating power, thermal and exergy efficiencies of the proposed combined cycle have been studied. The results show that for the investigated case in the proposed combined cycle, the amount of the produced hydrogen, net generating power and energy, and exergy efficiency were 1536kg/hr, 12.83MV, 11.39% and 43.64%, respectively. Increasing the pressure of the separators was not effective in increasing hydrogen production, while with increasing the first separator pressure, as well as, the second separator pressure to the optimum pressure, the thermal and exergy efficiency increase. With increasing the temperature of the proton membrane electrolyzer, the produced hydrogen discharge increases and while maintaining cycle net output power, thermal and exergy efficiencies increase. Also, at the optimum point for high-pressure Kalina, the maximum amount of hydrogen production is obtained. The highest amount of exergy degradation was obtained for the protonated membrane electrolyzer, evaporator and condenser 2, respectively.