The paper reports the effects of surface fractal structures on the rheological behavior and combustion kinetics of raw brown coal and three modified coal water slurries （CWSs）. The results show that the fractal stru...The paper reports the effects of surface fractal structures on the rheological behavior and combustion kinetics of raw brown coal and three modified coal water slurries （CWSs）. The results show that the fractal structures and physicochemical properties of samples are dependent on various modification processes. The apparent viscosities of the coal water slurries increase with increasing surface fractal dimensions （D）, especially with decreasing shear rates. Fur- thermore, it has been proved that the ignition temperatures and apparent activation energies of modified CWSs are lower than that of raw coal water slurry. Compared with the traditional qualitative analysis of the effect of pore structures on CWSs properties, D can more efficiently indicate the quantificational effect of pore structures on the rheological behavior and combustion kinetics of CWSs.展开更多
A chemical kinetic method based on the kinetic expression of the second-order reaction on fractals is used to determine the spectral dimension of tractal dimension of fractal surfaces. The method can convemently give ...A chemical kinetic method based on the kinetic expression of the second-order reaction on fractals is used to determine the spectral dimension of tractal dimension of fractal surfaces. The method can convemently give the spectral dimension by analyzing the relation between reactant concentration and reaction time (ct～t). The spectral dimension of the Diffusion-Limited Aggregate (DLA) is obtanined by Monte Carlo simulation of the desorption process of chemisorbed hydrogen from DLA, and it is in agreement, with that in literature. Also, the spectral dimension of a real catalyst12% Ni/Al2O3 is obtained by the method.展开更多
文摘The paper reports the effects of surface fractal structures on the rheological behavior and combustion kinetics of raw brown coal and three modified coal water slurries （CWSs）. The results show that the fractal structures and physicochemical properties of samples are dependent on various modification processes. The apparent viscosities of the coal water slurries increase with increasing surface fractal dimensions （D）, especially with decreasing shear rates. Fur- thermore, it has been proved that the ignition temperatures and apparent activation energies of modified CWSs are lower than that of raw coal water slurry. Compared with the traditional qualitative analysis of the effect of pore structures on CWSs properties, D can more efficiently indicate the quantificational effect of pore structures on the rheological behavior and combustion kinetics of CWSs.
文摘A chemical kinetic method based on the kinetic expression of the second-order reaction on fractals is used to determine the spectral dimension of tractal dimension of fractal surfaces. The method can convemently give the spectral dimension by analyzing the relation between reactant concentration and reaction time (ct～t). The spectral dimension of the Diffusion-Limited Aggregate (DLA) is obtanined by Monte Carlo simulation of the desorption process of chemisorbed hydrogen from DLA, and it is in agreement, with that in literature. Also, the spectral dimension of a real catalyst12% Ni/Al2O3 is obtained by the method.
