Thermodynamic and exergoeconomic assessment of a new combined power, natural gas, and hydrogen system based on two geothermal wells

Abstract

In the present study, the use of two geothermal wells with different temperatures and pressure characteristics was considered. The application of a combined system is a promising way to improve the system thermodynamically. The possibility of using the combined systems with two geothermal wells has not yet been done. As an attempt to fulfill the gap in the field, a new combined power, natural gas, and hydrogen system was proposed considering two geothermal wells. The system consists of a novel flash configuration, Organic Rankine Cycle (ORC), Liquefied Natural Gas (LNG), and Proton Exchange Membrane (PEM) systems. The proposed system is investigated from energy, exergy, and exergoeconomic aspects. In addition, it aimed to perform a comprehensive parametric study and optimize the system. Engineering Equation Solver (EES) is used to perform the simulation and optimization. The optimization results for the system at High Temperature Well (HTW) of 230 °C and Low Temperature Well (LTW) of 190 °C led to 3.575 kg/hr, 13490 kW, 21651 kW, 17.14%, 44.16%, and 19.86 $/GJ values for the hydrogen production, net output power, total exergy destruction, thermal efficiency, exergy efficiency, and power specific cost, respectively. Additionally, the parametric study showed that the net output power, as well as the thermal and exergy efficiencies, increase by increasing the temperature of HTW and have maximum values with the pressure of separators while the hydrogen production has a constant value. Also, according to the result, the thermal efficiency has been improved by 3.18% compared to similar studies.