The stability and activity of alkaline carbonate catalysts in supercritical water coal gasification has been investigated using density functional theory method. Our calculations present that the adsorption of Na2CO3 ...The stability and activity of alkaline carbonate catalysts in supercritical water coal gasification has been investigated using density functional theory method. Our calculations present that the adsorption of Na2CO3 on coal are more stable than that of K2CO3, but the stability of Na2CO3 is strongly reduced as the cluster gets larger. In supercritical water system, the dispersion and stability of Na2CO3 catalyst on coal support is strongly improved. During coal gasification process, Na2CO3 transforms with supercritical water into NaOH and NaHCO3, which is beneficial for hydrogen production. The transformation process has been studied via thermodynamics and kinetics ways. The selectively catalytic mechanism of NaOH and the intermediate form of sodium-based catalyst in water-gas shift reaction for higher hydrogen production has also been investigated. Furthermore, NaOH can transform back to Na2CO3 after catalyzing the water-gas shift reaction. Thus, the cooperative effects between supercritical water and Na2CO3 catalyst form a benignant circle which greatly enhances the reaction rate of coal gasification and promotes the production of hydrogen.展开更多
The world is endowed with a tremendous amount of coal resources,which are unevenly distributed in a few nations.While sustainable energy resources are being developed and deployed,fossil fuels dominate the current wor...The world is endowed with a tremendous amount of coal resources,which are unevenly distributed in a few nations.While sustainable energy resources are being developed and deployed,fossil fuels dominate the current world energy consumption.Thus,low-carbon clean technologies,like underground coal gasification(UCG),ought to play a vital role in energy supply and ensuring energy security in the foreseeable future.This paper provides a state-of-the-art review of the world's development of UCG for enhanced hydrogen production.It is revealed that the world has an active interest in decarbonizing the coal industry for hydrogen-oriented research in the context of UCG.While research is ongoing in multiple coal-rich nations,China dominates the world's efforts in both industrial-scale UCG pilots and laboratory experiments.A variety of coal ranks were tested in UCG for enhanced hydrogen output,and the possibilities of linking UCG with other prospective technologies had been proposed and critically scrutinized.Moreover,it is found that transborder collaborations are in dire need to propel a faster commercialization of UCG in an ever-more carbon-conscious world.Furthermore,governmental and financial support is necessary to incentivize further UCG development for large-scale hydrogen production.展开更多
基金supported by the National High-Tech Research and Development Program of China(2011AA05A201)the National Natural Science Foundation of China(21106094)Tianjin Science Foundation for Youths,China(12JCQNJC03100)
文摘The stability and activity of alkaline carbonate catalysts in supercritical water coal gasification has been investigated using density functional theory method. Our calculations present that the adsorption of Na2CO3 on coal are more stable than that of K2CO3, but the stability of Na2CO3 is strongly reduced as the cluster gets larger. In supercritical water system, the dispersion and stability of Na2CO3 catalyst on coal support is strongly improved. During coal gasification process, Na2CO3 transforms with supercritical water into NaOH and NaHCO3, which is beneficial for hydrogen production. The transformation process has been studied via thermodynamics and kinetics ways. The selectively catalytic mechanism of NaOH and the intermediate form of sodium-based catalyst in water-gas shift reaction for higher hydrogen production has also been investigated. Furthermore, NaOH can transform back to Na2CO3 after catalyzing the water-gas shift reaction. Thus, the cooperative effects between supercritical water and Na2CO3 catalyst form a benignant circle which greatly enhances the reaction rate of coal gasification and promotes the production of hydrogen.
基金funded by PetroChina Research Institute of Petroleum Exploration&DevelopmentThe support of Department of Chemical and Petroleum Engineering,University of Calgary and Reservoir Simulation Group is gratefully acknowledged+1 种基金supported by NSERC/Energi Simulation,AITF(iCore),IBM Thomas J.Watson Research Center,and the Energi Simulation/Frank and Sarah Meyer Collaboration Centre for Visualization and Simulationsupport provided by WestGrid and Compute Canada Calcul Canada.
文摘The world is endowed with a tremendous amount of coal resources,which are unevenly distributed in a few nations.While sustainable energy resources are being developed and deployed,fossil fuels dominate the current world energy consumption.Thus,low-carbon clean technologies,like underground coal gasification(UCG),ought to play a vital role in energy supply and ensuring energy security in the foreseeable future.This paper provides a state-of-the-art review of the world's development of UCG for enhanced hydrogen production.It is revealed that the world has an active interest in decarbonizing the coal industry for hydrogen-oriented research in the context of UCG.While research is ongoing in multiple coal-rich nations,China dominates the world's efforts in both industrial-scale UCG pilots and laboratory experiments.A variety of coal ranks were tested in UCG for enhanced hydrogen output,and the possibilities of linking UCG with other prospective technologies had been proposed and critically scrutinized.Moreover,it is found that transborder collaborations are in dire need to propel a faster commercialization of UCG in an ever-more carbon-conscious world.Furthermore,governmental and financial support is necessary to incentivize further UCG development for large-scale hydrogen production.
