Analysis of Factors Affecting Energy Consumption in Hydrogen Liquefaction Plants

Hydrogen energy, valued for its diverse sources and clean, low-carbon nature, is a promising secondary energy source with wide-ranging applications and a significant role in the global energy transition. Nonetheless, hydrogen's low energy density makes large-scale storage and transport challenging. Liquid hydrogen, with high energy density and easier transport, offers a practical solution. This study examines global hydrogen liquefaction methods, with particular emphasis on the liquid nitrogen pre-cooling Claude cycle process. It also examines the factors in the helium refrigeration cycle—such as the helium compressor inlet temperature, outlet pressure, and mass—that affect energy consumption in this process. Using HYSYS software, the hydrogen liquefaction process is simulated, and a complete process system is developed. Based on theoretical principles, this study explores the pre-cooling, refrigeration, and normal-to-secondary hydrogen conversion processes. By calculating and analyzing process energy consumption, an optimized flow scheme for hydrogen liquefaction is proposed to reduce the total power used by energy equipment. The study shows hydrogen mass flow rate and key helium cycle parameters—like compressor inlet temperature, outlet pressure, and flow rate—mainly affect energy consumption. By optimizing these parameters, notable decreases in both total and specific energy consumption were attained. The total energy consumption dropped by 7.266% from the initial 714.3 kW, and the specific energy consumption reduced by 11.94% from 11.338 kWh/kg.