Techno-Economic Analysis of Diphenylmethane as a Liquid Organic Hydrogen Carrier with Leveraging Industrial Waste Heat for Sustainable Hydrogen Infrastructure

This study investigates an innovative solution to enhance the efficiency of the hydrogen supply chain through the incorporation of high-temperature waste heat from the steel industry into the liquid organic hydrogen carrier (LOHC) system. Diphenylmethane (DPM) is selected as the LOHC due to its high thermal stability and the notable hydrogen storage capacity (6.7 wt %). A complete simulation framework is established, using DWSIM for the PEM electrolysis and Aspen Plus V12 for the hydrogenation and dehydrogenation process. A unique aspect of this investigation is the comprehensive exergy and economic analysis comparing three different hydrogen delivery pathways: conventional compressed hydrogen, LOHC utilizing external industrial waste heat for dehydrogenation, and LOHC utilizing internal hydrogen burning. Among these, the waste heat-integrated LOHC (scenario 2) shows the highest exergy efficiency (61.32%), highlighting the potential of heat recovery to enhance the system performance. Nonetheless, the most economical solution (3.10 $/kg) is LOHC with waste heat integration (scenario 2), and the most favorable indicators of investment (NPV: 1727.41 M$, IRR: 27.78%, PBP: 3.41 years) are obtained. This is the first study to present a direct quantitative comparison between compressed hydrogen and DPM as LOHC systems, emphasizing the trade-offs between thermodynamic efficiency and economic viability. It also provides pathways to make LOHC technologies more competitive in real-world hydrogen infrastructure.