Exploring the potential of liquid organic hydrogen carrier (LOHC) system for efficient hydrogen storage and Transport: A Techno-Economic and energy analysis perspective

Despite its potential as an environmentally clean fuel and energy source, hydrogen storage and utilization has been significantly hampered by its extremely low volumetric density (0.08988 g/L at 1 atm), making it inefficient to store and transport. Therefore, liquid organic hydrogen carrier (LOHC) systems are being recently investigated as potential alternatives for hydrogen storage and transport. However, as a budding research area, the selection of a suitable LOHC, its deployment in hydrogen fuel stations, and its economic viability are not well established. Therefore, this study proposes a comprehensive investigation of four different LOHCs [Methylcyclohexane (MCH), Dibenzyltoluene (DBT), N-ethylcarbazole (NEC) and Naphthalene (NAP)] via Aspen HYSYS simulations. The LOHCs were compared and contrasted using their physiochemical properties, techno-economic analysis and heat network integration. The techno-economic analysis revealed that NAP-based hydrogen storage has the lowest cost among the LOHC options, while NEC shows the highest cost. However, when considering the breakeven point, the order changes to DBT, MCH, NAP, and NEC with 3, 3.8, 5.1 and 5.9, respectively. This result is attributed to the different hydrogen uptakes of the LOHCs, resulting in a longer breakeven period for NEC. Internal rate of return and net present value analysis also demonstrated the superior economic feasibility of the proposed systems. In terms of heat integration, the DBT process outperformed the other LOHCs as the most heatefficient process with 80 % utility reduction, while the NEC process exhibited the lowest heat integration potential of 66.7 % utility reduction. Combining these findings with the physiochemical properties of the LOHCs, DBT emerges as the most attractive due to its favorable performance across multiple categories, such as toxicities, prices, energy consumptions, and material handling, using a spiderweb diagram.