Assessment of an integrated solar hydrogen system for electrochemical synthesis of ammonia

In this paper, a solar based electrochemical system is designed, built and tested to synthesize ammonia and hydrogen from nitrogen and saturated steam. Ammonia can serve as a sustainable fuel and is in heavy demand by the fertilizer industry. However, the conventional methods rely on hydrogen produced from fossil fuels. Hydrogen can be supplied back by implementing fuel cells and feeding electricity back to the system, directed to the conventional ammonia production methods as a reactant, or sold as a fuel. A simple and direct system is studied to pose a sustainable option for ammonia and hydrogen production. Very high concentrations of Nano iron catalyst are used to promote the concentration of ammonia at the output. The reactor is designed for continuous flow and can be disassembled for varying tests and scenarios. The maximum concentration of ammonia is found to be 950 ppm measured with excess reactant supply. Increasing nitrogen flow rates along with decreasing steam flow rates render increasing concentration results. The system at optimum conditions consumes 650 mA at 1.7 V. The low power requirements and valuable products of the system encourage further studies. Additionally, a solar energy based system is proposed as a renewable approach to ammonia synthesis with a fuel cell component to increase the efficiency by reducing the power consumption to 60% of its original value. (C) 2017 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.