Dynamic Modelling and Control of Sorption-Enhanced Green Ammonia Synthesis Integrated with PEM Electrolysis

Taranets, Elizaveta

4. term

Energy Engineering, Master

2025

2025-05-27

65 pages

With the growth of renewable energy, storing and transporting its intermittent supply remains a major challenge. The Power-to-X (PtX) concept offers a pathway by converting renewable electricity into valuable products, enabling long-term energy storage. Ammonia (NH3), a carbon-free hydrogen carrier, has gained attention as a key product in Power-to-Ammonia (PtA) systems. Green NH3 synthesis provides a sustainable alternative to the CO2-intensive Haber-Bosch process. However, conventional reactors operating at high temperature and pressure are not suited for dynamic conditions. This study addresses the challenge of adapting NH3 synthesis process to fluctuating renewable power by investigating a novel sorption-enhanced NH3 reactor designed for flexible operation under mild conditions. A Computational Fluid Dynamics (CFD) model of the absorption-integrated NH3 synthesis reactor was developed. Then a steady-state Functional Mock-up Unit (FMU) using a response surface method was developed based on the CFD model data, enabling its integration with other PtA plant components in MATLAB/Simulink. The integrated model was used to explore operational feasibility and NH3 reactor control strategies for managing fluctuating H2 supply. Among the scenarios tested, employing two reactors operating in parallel during peak H2 production, demonstrated the highest effective NH3 output (33.1 kg/day) and lowest specific energy consumption (17 kWh/kg). The results demonstrate that integrating flexible, absorption-enhanced NH3 reactors with intermittent renewable energy can be technically feasible. While the economic analysis showed the high capital cost of reactors and electrolyzers, making such systems less economically competitive.

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