Performance Simulation And Analysis Of Ammonia-fueled Solid Oxide Fuel Cell Combined System

Energy and environmental issues have always been significant international challenges.The “dual carbon goals” has promoted the development of marine fuels in the direction of low carbon and zero carbon,and ship power units and systems have shown a diversified development trend.Solid oxide fuel cells have been the focus of research on ship power because of their high efficiency,ultra-low emissions and pollution-free advantages.They can recover the waste heat and residual matter of the stack when combined with other devices.The traditional bottom cycle device coupled with the fuel cell can not make good use of the waste energy potential of the fuel cells.To solve this problem,three solid oxide fuel cell combined systems have been designed to comprehensively compare their thermodynamic and economic performances.Specifically,the following work will be carried out:(1)The ammonia-fueled solid oxide fuel cell model was established based on Python language and verified based on existing literature experiments.According to the modeling results,the parameter analysis was carried out to determine the influence of the critical operating parameters of the solid oxide fuel cell system on the system performance.SOFC standalone system was analyzed under selected design conditions as the basis for optimal design of joint systems.(2)Based on Cantera calculation software library and Python language,a homogeneous compression ignition engine model was established and verified,the afterburner of the standalone system was replaced by the HCCI engine,and the SOFC-ICE series circulation system scheme was designed by using the SOFC exhaust gas to generate additional output power;The Karina cycle system model was established and verified,and the Karina cycle was used as the bottom cycle to recover the waste heat of the SOFC system.The ammonia engine model was established and verified,and the ammonia fuel SOFC-ICE parallel cycle system scheme was designed.The influence of operating parameters on the performance of combined systems were analyzed and the optimal operating conditions of each subsystem was determined.The results show that under the design conditions,the efficiency of SOFC-HCCI combined system is 66.6%,the efficiency of SOFC-KCS combined system is 58.8%,and the efficiency of SOFC-ICE parallel system is 55%.(3)A thermodynamic and economic analysis model was established,and thermodynamic analysis of the combined system was conducted based on the model to ensure that the system reaches thermal equilibrium,and compare and analyze the solid oxide fuel cell standalone system and the fuel cell-engine cycle configuration to comprehensively evaluate the thermal and economic performance of the system.The results show that at a stack output power of2400 k W,the efficiency of the series cycle system of SOFC-HCCI engine is 10.2% higher than that of SOFC standalone system,and the efficiency is increased by 3.9%.At a total output of2400 k W,the ammonia-fueled SOFC-ICE parallel cycle system also performs significantly better than the standalone engine system.Through economic comparison,it was concluded that the power generation cost of ammonia fuel SOFC-ICE parallel system is the lowest,followed by SOFC-HCCI series system,and the power generation cost of SOFC standalone system is the highest.Comprehensively considered,the SOFC-ICE parallel system will be a better choice for offshore applications.