Simulation of an innovative hydrogen liquefaction concept for using gas power-plant’s wasted energy

Document Type : Research Article

Authors

1 Mechanical Engineering, Faculty of Mechanical Engineering, K.N. Toosi university of technology, Tehran, Iran

2 Professor, Faculty of Mechanical Engineering, K.N. Toosi university of technology, Tehran, Iran

3 Assistant Professor, Faculty of Mechanical Engineering, Imam Khomeini International University, Qazvin, Iran

Abstract

Due to the importance of hydrogen liquefaction and the low efficiency of existing liquefaction plants, many researches are done to develop a proper liquefaction concept. Utilizing innovative configurations, the use of geothermal and solar energy for absorption pre-cooling systems have been extensively investigated through various studies. In the present study, an innovative concept for hydrogen liquefaction is developed and simulated by Aspen HYSYS V. 9, which utilized absorption pre-cooling supplied by wasted heat contained in gas power-plant’s exhaust flow. Using two separate equations of state for hydrogen and mixed refrigerant streams and realistic assumption about heat exchangers and turbo-machines have increased the accuracy, besides making it practical. The simulation results show that the developed concept has a better performance in terms of specific energy consumption and coefficient of performance in comparison to the other proposed concepts, so that the specific energy consumption and coefficient of performance are 4.55 kWh/kgLH2 and 27%, respectively. In addition, the suggested concept could be supplied directly by power-plant due to the requirement of being close to the power plant. This removes power distribution losses. Other key feature of the proposed concept, which sets it apart from the other concepts, is its capability to be used for energy storage.

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