TECHNO-ECONOMICS OF ELECTRIFIED AMMONIA CRACKING FOR HYDROGEN PRODUCTION

Nowadays, the energy sector is the source of about three-quarters of greenhouse gas emissions, precursors of climate change that negatively affect the entire world with extreme weather conditions. It is recognized that hydrogen plays a pivotal role in ensuring an effective penetration of renewable electricity into the energy mix. Due to the difficulties in long-distance hydrogen transport, a promising solution is to embody hydrogen into an easier-to-deal carrier like ammonia, thus freeing the already-available NH3 infrastructures for practical H2 storage and transport. Different solutions have been proposed to reconvert ammonia into hydrogen at the delivery point. This thesis aims to conduct a techno-economic feasibility assessment on electrified ammonia decomposition (cracking) as a carbon-free hydrogen production method. Four different configurations with a productivity of 100 Nm3/h of high-purity “green” hydrogen are conceptualized and simulated in Aspen Plus®. Non-recovered high-energy content species exiting the reactor are combusted to generate heat to be integrated into the process, increasing the thermal efficiency. Moreover, part of the heat is used in the cracking reactor to provide a convective duty for the endothermic NH3 decomposition. The residual power for ammonia cracking, instead, is provided electrically. A specific configuration that provides a fully electrified cracking reactor is discussed and compared to traditional heating. A techno-economic analysis is performed based on the process flowsheets in terms of capital and manufacturing costs, profitability and sensitivity analysis on the costs of raw material (ammonia), electricity and plant's installed equipment. The electrified cracking represents the most economically advantageous solution; however, the selling price of green H2 strongly influences the profitability of the process.