基于LNG冷能的氢液化系统分析与优化OA

Objective This study aims to enhance the efficiency of a hydrogen liquefaction system,recover high-temperature waste heat from the steam methane reforming(SMR)hydrogen production process,reduce CO2 emissions,and meet future energy demands.Method A hydrogen liquefaction system precooled by liquefied natural gas(LNG)cold energy and combined with a subcritical CO2 regenerative Rankine cycle was proposed to recover high-temperature waste heat from SMR and capture CO2.The influence of key parameters on the system was determined through parametric analysis.The composite curves of heat exchangers and the exergy losses of the equipment were particularly analyzed.The system was optimized based on particle swarm optimization,and its superiority was demonstrated through comparative analysis.Result The results show that the specific energy consumption of the system is 6.82 kWh/kg,the coefficient of performance is 0.195,the exergy efficiency is 59.66%,and the CO2 capture rate is 60.15%.The total exergy loss of the system is 1071.28 kW,mainly distributed in steam turbines and heat exchangers.Conclusion The hydrogen liquefaction system with waste heat recovery has a specific energy consumption that is 0.66 kWh/kg lower,while the exergy efficiency is 3.53 percentage points higher and the energy efficiency ratio is 13.37%higher than that of the conventional system.The research results can serve as a reference for future hydrogen liquefaction processes.