Material Selection of Tanks for Storage and Transport of Liquid Organic Hydrogen Carriers: A Lightweight and Lifecycle Assessment Comparative Study of Metal, Polymer, and Composite Alternatives

Liquid organic hydrogen carriers (LOHCs) are a key technology for a decarbonized industrial production. A comparative study on the material selection of tanks for the storage and transport of LOHC is presented. Three material classes are compared: metals (steel), polymers (thermoplastic), and composites (glass fiber-reinforced plastic). Considering existing standards, two sizes of tanks (150 and 700 m3) are dimensioned based on scenario requirements of loading and environmental conditions specific to the transport of the LOHC benzyltoluene. Thermoplastic tanks fulfilling the requirements are significantly heavier even than steel tanks, while the lowest tank mass can be achieved using glass fiber-reinforced plastics (GFRP). Concerning GFRP: 1) a resin with suitable chemical resistance is preferable over a thermoplastic lining; 2) a construction geometry with a flat bottom and curved roof improves lightweight; and 3) woven roving yields lighter tanks than chopped strand mats. Lifecycle assessment for mobile and stationary tanks indicates that GFRP offers the smallest CO2 emissions for mobile tanks due to fuel savings, while steel is preferable for stationary tanks. In this regard, advancements in circularity and bio-based raw materials for composites can improve GFRP's ecological balance for LOHC applications.