Modeling of Solar Ammonia Production Using ASPEN Plus

A steady-state model of green ammonia production using hydrogen produced from Polymer Electrolyte Membrane (PEM) electrolysis has been developed using ASPEN Plus Simulation software. Since the ASPEN plus does not offer the facility to directly model electrolysis cells, Aspen Custom Modeler (ACM) is used to develop the PEM stack. Stack is based on semi-empirical equations describing cell voltage and water transport across the membrane. The power requirement for electrolysis is expected to come from solar energy. This model of the PEM electrolyzer is integrated with the ammonia production model in a single flowsheet. With a power input of 4.25 kW, the PEM stack with 26 cells produced 0.048 kmol/h of H2. The corresponding ammonia production utilizing the conventional Haber–Bosch reactor was simulated to be 0.026 kmol/h. Such a model is expected to assist in the future design and scale-up of green ammonia processes.