A HIGH-PERFORMANCE DUAL-STAGE HYDROGEN COMPRESSOR SYSTEM USING Ca_(0.2)Mm_(0.8)Ni_5 METAL HYDRIDE

摘要

Dual stage hydrogen compressor with high pressure compression ability can operate efficiently using geothermal, low temperature solar, waste energy as well as combination of these energy sources. In this study, a dual stage thermal compressor system for hydrogen compression was investigated using three different hydrogen storage materials: LaNi_5, Ca_(0.6)Mm_(0.4)Ni_5 and Ca_(0.2)Mm_(0.8)Ni_5. Compression ratio of Ca_(0.2)Mm_(0.8)Ni_5 was found to be 56% and 14.7% higher than those of LaNi_5 and Ca_(0.6)Mm_(0.4)Ni_5 respectively, for single stage thermal compressor system with inlet supply pressure of 600 psig. On the other hand, compression performance of Ca_(0.2)Mm_(0.8)Ni_5 was similar to that of LaNi_5 at low supply pressure (e.g. 200 psig) condition. In this paper, a dual stage hydrogen compressor system with LaNi_5 in first stage and Ca_(0.2)Mm_(0.8)Ni_5 in second stage is proposed for high pressure hydrogen compression based on the experimental results of single stage system. Results show that 53% higher compression ratio can be attained using dual stage hydrogen compressor when appropriate storage materials are selected for two stages.