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Abstract
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Nowadays, with the depletion of underground resources and the increase in carbon dioxide, humans are obliged to use renewable energy. Liquid hydrogen production as one of the clean energy carriers with proper storage capability and transport to distant places has attracted a lot of attention. One of the main problems of hydrogen liquefaction cycles is the high power consumption for purification and liquefaction. In this paper, a novel in-
tegrated structure of hydrogen purification and liquefaction is developed using natural gas steam reforming, organic Rankine cycle, and photovoltaic panels. This integrated structure produces 1020 kmol/h liquid hydrogen and 3321 kmol/h fuel gas. The energy and exergy efficiencies of the integrated structure are 74.15% and 72.41%, respectively. The specific power consumption of the pre-cooling and purification, liquefaction, and total hydrogen purification-liquefaction cycles are 5.909, 2.725, and 8.592 kWh/ kgLH₂, respectively. The exergy analysis of the integrated structure exhibits that the highest exergy destruction occurs in heat exchangers (44.51%) and reactors (17.59%). The impact of different parameters on the performance of the integrated structure is studied. The sensitivity analysis demonstrates that the power energy consumption decreases up to 7.881 kWh/ kgLH2 and exergy efficiency increases up to 0.801 when the methane content in inlet natural gas flow increases from 82 to 92 mol%. The thermal efficiency and productivity of the liquid hydrogen increase up to 0.7851 and 1084 kmol/h, respectively with the increase of reformer temperature from 550 ◦C to 650 ◦C.
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