A novel integrated hydrogen and natural gas liquefaction process using two multistage mixed refrigerant refrigeration systems

Abstract

The development and analysis of combined hydrogen and natural gas liquefaction process are reported. Two refrigeration cycles using mixed refrigerants (MRs) are employed. The developed process is capable of generating 290 tons hydrogen and 296 tons liquid natural gas on daily basis. The first refrigeration cycle of the introduced process liquefies 3.5 kg·s−1 normal gaseous hydrogen and 3.5 kg·s−1 normal natural gas at room temperature and 21 bar to −195°C with the consumed power of 0.643 kWh/kgLH2,kgLNG. The second refrigeration cycle cools down the hydrogen and natural gas to −253°C with the consumed power of 1.662 kWh/kgLH2,kgLNG, leading to a lower total consumed power than that of the identical liquefaction processes. The use of novel and appropriately mixed refrigerants based on the configuration, and the thermal design of expanders and heat exchangers fora wide range of temperatures are the innovations of the process. Additionally, the refrigerant compositions of refrigeration cycles are novel. The energy analysis indicated that the coefficient of performance (COP) for the developed process is 0.2442, which is notably high compared with the COP of other identical processes (typically less than 0.1797). The exergy analysis revealed that the overall exergy efficiency of the liquefaction process is 62.54%. Highlight edited A novel integrated hydrogen and natural gas liquefaction process is introduced. The process can generate 290 tons hydrogen and 296 tons liquid natural gas per day. Total power consumptions of the process are 4.165 kWh/kgLH2,kgLNG. Coefficient of performance (COP) for the developed process is 0.2442, which is notably high compared with the COP of other identical processes. Overall exergy efficiency of the liquefaction process is 62.54%.