A novel multigeneration ammonia-based carbon capturing system powered by a geothermal power plant for cleaner applications

This work presents a novel integrated system for the multigeneration of power, space heating, freshwater, and ammonium bicarbonate as a useful chemical commodity with a geothermal-based carbon capturing system. A thermodynamic model based on energy and exergy analyses is developed for this integrated system. The results from the model show that the new carbon capturing unit that is based on an electrochemical ammonia synthesizer requires 13.3% less energy to capture the carbon dioxide released from the solid-oxide fuel cell subsystem than using a combination of proton-exchange membrane electrolyzer and a Haber-Bosch process. Also, the present integrated system produces ammonium bicarbonate sufficiently at a rate of 0.634 kg s(-1), when the fuel cell produces 2010 kW of electric power. In addition, the energy and exergy efficiencies of the solid-oxide fuel cell subsystem are found to be 44.5%, and 50.5%, respectively. Then, parametric studies are conducted to see how this integrated system behaves under varying conditions. It is found that the geothermal fluid and the faradaic efficiency of the electrochemical ammonia synthesizer have major effects on the performance of the geothermal-based carbon capturing system and they can lower the energy requirements of the carbon capturing to as low as 8.28 MJ kg(-1) of carbon dioxide.