Dynamic modeling and techno-economic analysis of a heat-integrated NH3 cracking plant for cost-effective H2 production under uncertainty

This study conducted a techno-economic analysis of a heat-integrated NH3 cracking plant for cost-effective H2 production under minimizing carbon emissions. The dynamic mathematical models of a tubular NH3 cracker and a temperature swing adsorption (TSA) process were developed, which provided the operational insights through the dynamic behaviors of temperature and composition. Then, the entire NH3 cracking plant was analyzed by a hybrid model by linking their steady-state results with other facility simulation. The multi-dimensional dynamic model for cracker identified hot spot positions along with temperature distribution and pressure drop. A heat duty of cracker was 79.25 kJ/mol-NH3 at GHSV 1800 h−1 and preheating temperature of 623.15 K. To selectively remove unreacted trace NH3 in the cracked gas, the TSA using zeolite 4A required a heat duty of 36.08 kJ/mol-NH3 and a cooling duty of 36.32 kJ/mol-NH3. A plant-wide heat exchanger network (HEN) was designed by the hybrid model developed for the entire plant. Pinch analysis confirmed that the proposed HEN achieved a heat recovery rate of 94.56 %, approaching the thermodynamic limit. In comparative sensitivity analysis with a conventional plant, the heat-integrated NH3 cracking plant could achieve net energy consumption of 36.79 kJ/mol-NH3 and energy conversion rate of 84.19 %. Additionally, the economic analysis with Monte Carlo simulation for 500,000 economic scenarios indicated H2 production cost of 6.44 USD/kg-H2, specific profit of 0.35 USD/kg-NH3, and net present value (NPV) of 244 million USD. This study demonstrates the economic viability of industrial-scale low-carbon H2 production via NH3 cracking pathway.