Aspects of hydrogen liquefier scale-up – process and equipment design.

Hydrogen has recently come into focus as potential future energy carrier. Distributing the required hydrogen in liquefied state offers several advantages and the demand for liquid hydrogen (LH2) will increase in the near future. The relatively low efficiency and high specific costs of today’s small hydrogen liquefaction plants is a drawback. The capacity of new liquefiers is therefore expected to increase considerably. The implementation of such large-scale hydrogen liquefaction plants requires highly efficient process designs with low technological risk and optimized total cost of ownership. For large-scale liquefaction processes, a specific energy consumption SEC close to 6 kWh per kg LH2 with a significant reduction in specific liquefaction costs were achieved with the recent process development and optimization carried out by Linde Kryotechnik AG in cooperation with the Institute of Plant and Process Technology of the TU Munchen [1, 2, 3]. The focus of this paper is set on the main aspects of equipment and process integration to be considered in the development of cost-optimized liquefaction processes. With regard to the optimal balance between technical readiness, efficiency and costs, the challenges as well as the opportunities in the upscaling of process equipment are discussed for a 100 metric tons per day (tpd) liquefier developed within this work. A special consideration is given to the design of cycle compressors, cryogenic expanders and plate-fin heat exchangers with catalytic ortho-to para-hydrogen conversion.