Carbon emission and energy efficiency analysis of ammonia produc-tion routes in China from life-cycle perspective and prospects
The cornerstone of China's dual-carbon goal lies in the decarbonization and cleansing of the energy system.In the future,with wind power,photovoltaic power and other primary energy crowding into the grid,the volatility and intermittency force cross-seasonal wide-area energy storage technology becoming a pressing need.The characteristics of ammonia,such as stability,susceptibility to storage,and integrity of transmission and storage facilities,enable it to become a highly competitive chemical energy storage media,which is promising to break the current hydrogen storage and transportation challenges,and help realize the dual-carbon goal.Little work has been done on the life cycle assessment of ammonia pathway for large-scale application in China,lacking the assessment and analysis of carbon emission and energy efficiency indexes of the whole life cycle of ammonia pathway taking into account the subsections.Aiming at the above opportunities and challenges in the development of ammonia energy storage technology,we establish a life cycle assessment(LCA)integrated model of ammonia production at each major stage,evaluate and analyze the primary energy input and carbon emission of different ammonia production routes during their life cycle by combining with low carbon emission technology.This work identifies the key stages and factors contributing to carbon emissions and proposes technological improvements to reduce them,mainly through accounting for carbon emissions and energy efficiency of four technology routes,namely,ammonia from coal(R1),ammonia from natural gas(R2),ammonia from hydrogen driven by utility power(R3),and ammonia from hydrogen driven by renewable electricity(R4),and sensitivity analyses of the key parameters.It is found that the carbon emissions of the coal-to-ammonia(R1-w/o CCS)and natural gas-to-ammonia(R2-w/o CCS)routes without CCS are as high as 4.190 and 2.356 kg CO2/kg NH3,respectively,with the R3 route emitting 6.384,and 0.569 and 0.335 kg CO2/kg NH3 for the renewable power hydrogen to ammonia route with photovoltaic power plant(R4-PV)and wind power plant(R4-Wind)as the power inputs,respectively.This work provides a reliable analysis of process improvement scenarios for different ammonia production pathways by defining uniform system boundaries to improve the accuracy and comparability of the model in terms of carbon emissions and energy efficiency throughout the life cycle.
万方数据
维普
