The performance characteristics of isothermal fluidized bed syngas methanation for substitute natural gas are investigated over a self-made Ni–Mg/Al2O3 catalyst. Via atmospheric methanation in a laboratory fluidized ...The performance characteristics of isothermal fluidized bed syngas methanation for substitute natural gas are investigated over a self-made Ni–Mg/Al2O3 catalyst. Via atmospheric methanation in a laboratory fluidized bed reactor it was clarified that the CO conversion varied in 5% when changing the space velocity in 40–120 L·g-1·h-1but the conversion increased obviously by raising the superficial gas velocity from 4 to12.4 cm·s-1. The temperature at 823 K is suitable for syngas methanation while obvious deposition of uneasyoxidizing Cγoccurs on the catalyst at temperatures around 873 K. From a kinetic aspect, the lowest reaction temperature is suggested to be 750 K when the space velocity is 60 L·g-1·h-1. Raising the H2/CO ratio of the syngas increased proportionally the CO conversion and CH4 selectivity, showing that at enough high H2/CO ratios the active sites on the catalyst are sufficient for CO adsorption and in turn the reaction with H2 for forming CH4.Introducing CO2 into the syngas feed suppresses the water gas shift and Boudouard reactions and thus increased H2 consumption. The ratio of CO2/CO in syngas should be better below 0.52 because varying the ratio from 0.52 to0.92 resulted in negligible increases in the H2 conversion and CH4 selectivity but decreased the CH4 yield.Introducing steam into the feed gas affected little the CO conversion but decreased the selectivity to CH4. The tested Ni–Mg/Al2O3 catalyst manifested good stability in structure and activity even in syngas containing water vapor.展开更多
Road transport produces significant amounts of emissions by using crude oil as the primary energy source.A reduction of emissions can be achieved by implementing alternative fuel chains.The objective of this study is ...Road transport produces significant amounts of emissions by using crude oil as the primary energy source.A reduction of emissions can be achieved by implementing alternative fuel chains.The objective of this study is to carry out an economic,environmental and energy(EEE)life cycle study on natural gas-based automotive fuels with conven-tional gasoline in an abundant region of China.A set of indices of four fuels/vehicle systems on the basis of life cycle are assessed in terms of impact of EEE,in which natural gas produces compressed natural gas(CNG),methanol,dimethy-lether(DME)and Fischer Tropsch diesel(FTD).The study included fuel production,vehicle production,vehicle opera-tion,infrastructure and vehicle end of life as a system for each fuel/vehicle system.A generic gasoline fueled car is used as a baseline.Data have been reviewed and modified based on the best knowledge available to Chongqing local sources.Results indicated that when we could not change electric and hydrogen fuel cell vehicles into commercial vehicles on a large scale,direct use of CNG in a dedicated or bi-fuel vehicle is an eco-nomical choice for the region which is most energy efficient and more environmental friendly.The study can be used to support decisions on how natural gas resources can best be utilized as a fuel/energy resource for automobiles,and what issues need to be resolved in Chongqing.The models and approaches for this study can be applied to other regions of China as long as all the assumptions are well defined and modified to find a substitute automotive energy source and establish an energy policy in a specific region.展开更多
基金Supported by the National Natural Science Foundation of China(21161140329)the International Science&Technology Cooperation Program of China(2013DFG60060)the National Key Technology R&D Program(2010BAC66B01,2012BAC03B05)
文摘The performance characteristics of isothermal fluidized bed syngas methanation for substitute natural gas are investigated over a self-made Ni–Mg/Al2O3 catalyst. Via atmospheric methanation in a laboratory fluidized bed reactor it was clarified that the CO conversion varied in 5% when changing the space velocity in 40–120 L·g-1·h-1but the conversion increased obviously by raising the superficial gas velocity from 4 to12.4 cm·s-1. The temperature at 823 K is suitable for syngas methanation while obvious deposition of uneasyoxidizing Cγoccurs on the catalyst at temperatures around 873 K. From a kinetic aspect, the lowest reaction temperature is suggested to be 750 K when the space velocity is 60 L·g-1·h-1. Raising the H2/CO ratio of the syngas increased proportionally the CO conversion and CH4 selectivity, showing that at enough high H2/CO ratios the active sites on the catalyst are sufficient for CO adsorption and in turn the reaction with H2 for forming CH4.Introducing CO2 into the syngas feed suppresses the water gas shift and Boudouard reactions and thus increased H2 consumption. The ratio of CO2/CO in syngas should be better below 0.52 because varying the ratio from 0.52 to0.92 resulted in negligible increases in the H2 conversion and CH4 selectivity but decreased the CH4 yield.Introducing steam into the feed gas affected little the CO conversion but decreased the selectivity to CH4. The tested Ni–Mg/Al2O3 catalyst manifested good stability in structure and activity even in syngas containing water vapor.
基金This work was supported by the Chongqing Municipal Planning and Development Commission,Ford Motor Company as well as Changan Automobile(Group)Corporation.
文摘Road transport produces significant amounts of emissions by using crude oil as the primary energy source.A reduction of emissions can be achieved by implementing alternative fuel chains.The objective of this study is to carry out an economic,environmental and energy(EEE)life cycle study on natural gas-based automotive fuels with conven-tional gasoline in an abundant region of China.A set of indices of four fuels/vehicle systems on the basis of life cycle are assessed in terms of impact of EEE,in which natural gas produces compressed natural gas(CNG),methanol,dimethy-lether(DME)and Fischer Tropsch diesel(FTD).The study included fuel production,vehicle production,vehicle opera-tion,infrastructure and vehicle end of life as a system for each fuel/vehicle system.A generic gasoline fueled car is used as a baseline.Data have been reviewed and modified based on the best knowledge available to Chongqing local sources.Results indicated that when we could not change electric and hydrogen fuel cell vehicles into commercial vehicles on a large scale,direct use of CNG in a dedicated or bi-fuel vehicle is an eco-nomical choice for the region which is most energy efficient and more environmental friendly.The study can be used to support decisions on how natural gas resources can best be utilized as a fuel/energy resource for automobiles,and what issues need to be resolved in Chongqing.The models and approaches for this study can be applied to other regions of China as long as all the assumptions are well defined and modified to find a substitute automotive energy source and establish an energy policy in a specific region.
