Large-scale Hydrogen Liquefaction Methods and Devices

With the development of China's aerospace engineering and new energy technologies，hydrogen energy has been incorporated into China's energy strategy，becoming a strategic choice for optimizing energy consumption structure and ensuring national energy supply security. The liquefaction of hydrogen is an important part of the utilization of hydrogen energy，and it is also the guarantee of the economic and feasibility of hydrogen energy utilization. It briefly reviews the history of hydrogen liquefaction and highlights the methods，cycles，and devices for large- scale hydrogen liquefaction （LHL）. On the basis of comparing the characteristics of hydrogen liquefaction methods and hydrogen liquefaction plant in different periods，the development direction of large-scale hydrogen liquefaction plant in the future is further proposed， including improving the efficiency of main system components such as compressors，expanders and heat exchangers，highefficiency liquefaction cycle with self-cascading pre-cooling by mixed refrigerant，and new technology for replacing the throttle valve with a two-phase expander.