Coal water slurry gasification is a main source of hydrogen in the developing hydrogen economy.Moreover,biomass and waste can be added,making gasification process greener.To expand the application of coal water slurry...Coal water slurry gasification is a main source of hydrogen in the developing hydrogen economy.Moreover,biomass and waste can be added,making gasification process greener.To expand the application of coal water slurry and gasification process,it is necessary to understand the micro-structure in this large particle suspension system.In this paper,the micro-structure in coal water slurry was studied by extended DLVO(eDLVO)theory and fractal dimension,which is used to explain the mechanism of stability in large particle suspension systems.The interaction between two coal particles was characterized from the interparticle potential and energy barrier based on the eDLVO theory.The rheology and stability between different types of coals are measured and explained by the aggregating structure and fractal dimension in coal water slurry.The results indicated that there would be an aggregating structure in high rank coals,due to the interparticle potential caused by the surface properties,but probably not in low rank coals.This aggregating structure can be described and characterized by fractal dimension.The aggregation of particles is the source of the stability for high rank coals,as the close-packed 3D network structure in large particle suspension can support coal particles from settling down.The results have demonstrated that the combination of the eDLVO theory and rheological measurement is an effective way to investigate the stability of large particle suspension systems.展开更多
The mineral species in soils vary in a wide variety of places,thus resulting in the petroleumcontaminated soil(PCS)with complex characters.Thus,the research on the effect of mineral species on oil-soil interactions in...The mineral species in soils vary in a wide variety of places,thus resulting in the petroleumcontaminated soil(PCS)with complex characters.Thus,the research on the effect of mineral species on oil-soil interactions in PCS takes on a critical significance.In this study,the desorption and adsorption behaviors of aromatic hydrocarbons(Ar)on two minerals surfaces were examined.Meanwhile,the interfacial forces between minerals and Ar were studied and the sources of these forces were analyzed.Moreover,molecular dynamics(MD)simulations were conducted to gain insight into the interfacial interaction mechanisms.As revealed by the results of this study,in comparison with Qs-Ar(quartz sand,Qs),Mnt-Ar(montmorillonite,Mnt)contaminants required higher temperature and activation energies for thermal desorption(201.95 kJ·mol^(-1)vs.127.82 kJ·mol^(-1))The above difference was generated since the adhesive forces between Ar and Mnt surfaces were greater than those between Ar and Qs.As indicated by the analysis of the adhesion force sources,the van der Waals forces were responsible for facilitating oil adhesion to mineral surfaces,even though the electrostatic force prevented oil-mineral adhesion.Furthermore,the hydrophobic forces facilitated adhesion in 3 nm.The MD results demonstrated that compared with the Qs system,there existed larger binding energies between Ar and Mnt,a lower diffusion coefficient for Ar on the Mnt surface,as well as more significant adsorption of Ar on Mnt.In general,the different mineral species affect the strength of the interaction at the oil-soil interface,which is a guideline for proposing targeted oil-soil separation measures.展开更多
基金supported by the National Key Research and Development Program of China(Grant Nos.2017YFB0602602 and 2017YFB0602703)the Seed Fund of Shanxi Research Institute for Clean Energy,Tsinghua University,China.
文摘Coal water slurry gasification is a main source of hydrogen in the developing hydrogen economy.Moreover,biomass and waste can be added,making gasification process greener.To expand the application of coal water slurry and gasification process,it is necessary to understand the micro-structure in this large particle suspension system.In this paper,the micro-structure in coal water slurry was studied by extended DLVO(eDLVO)theory and fractal dimension,which is used to explain the mechanism of stability in large particle suspension systems.The interaction between two coal particles was characterized from the interparticle potential and energy barrier based on the eDLVO theory.The rheology and stability between different types of coals are measured and explained by the aggregating structure and fractal dimension in coal water slurry.The results indicated that there would be an aggregating structure in high rank coals,due to the interparticle potential caused by the surface properties,but probably not in low rank coals.This aggregating structure can be described and characterized by fractal dimension.The aggregation of particles is the source of the stability for high rank coals,as the close-packed 3D network structure in large particle suspension can support coal particles from settling down.The results have demonstrated that the combination of the eDLVO theory and rheological measurement is an effective way to investigate the stability of large particle suspension systems.
基金supported by the National Key Research and Development Program of China(2019YFE0115600)the National Natural Science Foundation of China(52074290)。
文摘The mineral species in soils vary in a wide variety of places,thus resulting in the petroleumcontaminated soil(PCS)with complex characters.Thus,the research on the effect of mineral species on oil-soil interactions in PCS takes on a critical significance.In this study,the desorption and adsorption behaviors of aromatic hydrocarbons(Ar)on two minerals surfaces were examined.Meanwhile,the interfacial forces between minerals and Ar were studied and the sources of these forces were analyzed.Moreover,molecular dynamics(MD)simulations were conducted to gain insight into the interfacial interaction mechanisms.As revealed by the results of this study,in comparison with Qs-Ar(quartz sand,Qs),Mnt-Ar(montmorillonite,Mnt)contaminants required higher temperature and activation energies for thermal desorption(201.95 kJ·mol^(-1)vs.127.82 kJ·mol^(-1))The above difference was generated since the adhesive forces between Ar and Mnt surfaces were greater than those between Ar and Qs.As indicated by the analysis of the adhesion force sources,the van der Waals forces were responsible for facilitating oil adhesion to mineral surfaces,even though the electrostatic force prevented oil-mineral adhesion.Furthermore,the hydrophobic forces facilitated adhesion in 3 nm.The MD results demonstrated that compared with the Qs system,there existed larger binding energies between Ar and Mnt,a lower diffusion coefficient for Ar on the Mnt surface,as well as more significant adsorption of Ar on Mnt.In general,the different mineral species affect the strength of the interaction at the oil-soil interface,which is a guideline for proposing targeted oil-soil separation measures.
