Analysis of the Comprehensive Utilization System of LNG Cold Energy And Geothermal Energy For Hydrogen Production

Liquefied natural gas (LNG) receiving terminals possess substantial cooling capacity due to the extremely low temperature of LNG. Hydrogen is a green and clean energy source with extremely high calorific value and is one of the best energy sources that can serve as an alternative to fossil fuels. Compared with fossil energy, hydrogen energy can avoid damage to the ecological environment and has a rather positive impact on carbon emissions. This paper takes a 3 million tons/year LNG receiving station as an example, proposes a hydrogen production system for the comprehensive utilization of LNG cold energy and geothermal energy, and uses HYSYS software to simulate the system. This system uses low-grade cold energy to maintain the temperature required for the operation of hydrogenase. The electrical energy generated by the second and fourth Rankine cycles is used for electrolyzing seawater to produce hydrogen, and the total hydrogen production capacity of the system reaches 200 kg/h. In addition, this system can generate 59.1628 million kilowatt-hours of electricity and 73,200 tons of hot water at 72°C every year, which can be used as the daily domestic water for workers and residents. After calculation, the initial investment of this system requires 212.061 million yuan, the annual net income is approximately 61.5744 million yuan, and the capital turnover cycle needs to be 3.4 years.