• Journal of the Korean Institute of Gas
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• v.15 no.6
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• pp.38-43
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• 2011

Natural gas liquefaction process runs under cryogenic condition, and it spends large amount of energy. Minimizing energy consumption of natural gas liquefaction process is an important issue because of its physical characteristics. Among many kinds of natural gas liquefaction processes, C3-MR(Propane Pre-cooled Mixed Refrigerant) process uses two kind of refrigerants. One is the propane as the pure refrigerant(PR) and the other is the mixed refrigerant(MR). In this study, to find the optimal compressing level, propane cycle is simulated on different pressure level. The case study result shows relationship between energy consumption and pressure level. As a result, the conclusion is that at a higher pressure level, process consumes lower energy. At 5 pressure-levels, energy consumption is 23.7% lower than 3 pressure-levels.

• Korean Chemical Engineering Research
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• v.59 no.2
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• pp.200-208
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• 2021

Compare to the gaseous hydrogen, liquid hydrogen has various advantages: easy to transport, high energy density, and low risk of explosion. However, the hydrogen liquefaction process is highly energy intensive because it requires lots of energy for refrigeration. On the other hand, the cold energy of the liquefied natural gas (LNG) is wasted during the regasification. It means there are opportunities to improve the energy efficiency of the hydrogen liquefaction process by recovering wasted LNG cold energy. In addition, hydrogen production by natural gas reforming is one of the most economical ways, thus LNG can be used as a raw material for hydrogen production. In this study, a novel hydrogen production and liquefaction process is proposed by using LNG as a raw material as well as a cold source. To develop this process, the hydrogen liquefaction process using hydrocarbon mixed refrigerant and the helium-neon refrigerant is selected as a base case design. The proposed design is developed by applying LNG as a cold source for the hydrogen precooling. The performance of the proposed process is analyzed in terms of energy consumption and exergy efficiency, and it is compared with the base case design. As the result, the proposed design shows 17.9% of energy reduction and 11.2% of exergy efficiency improvement compare to the base case design.