Search for the Best Processes to Liquefy Hydrogen in Very Large Plants

The goal of the IDEALHY project is to identify processes and components, which allow liquefying hydrogen with a power consumption much lower than with plants built so far. This requires comparing different possible processes concerning power efficiency, investment cost and compactness. The power consumption of a process depends on a number of boundary conditions. Without a clear overall definition of these boundary conditions, all statements and comparisons on the overall power consumption are questionable. So in the first step of the project the participants agreed on common boundary conditions.
Then it turned out, that the choice of the high pressure of the feed hydrogen influences strongly the rest of the liquefaction process, especially the region below 80 K. For this region there is an option between helium, hydrogen and neon as refrigerants and their mixtures. For the final choice of the working fluid and the process one has to identify the maximum possible circumferential speed of turbo compressors.