Gasification: Part I. Isothermal, kinetic control model for a solid with a pore size distribution

Hashimoto, Kenji; Silveston, P. L.

doi:10.1002/aic.690190209

Cited by 95 publications

(21 citation statements)

References 22 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…(12). This expectation is supported by the data within the limits of experimental error, as shown in Fig.…”

Section: Characteristics Of Parameter and Trpmsupporting

confidence: 72%

“…2), the inflection point of structure parameter x is around X = 0.7, and the parameter can be divided into two stages on the basis of Eq. (12), which is defined as: 0.7)), X ≥ 0.7 (12) in which x is structure factor in the TRPM. is a coefficient.…”

Section: Characteristics Of Parameter and Trpmmentioning

confidence: 99%

“…But only a limited number of studies have focused on the mechanism of coal chars combustion under oxyfuel conditions. Some researchers put forward different reaction models [9][10][11][12][13] to depict non-catalytic gas-solid reaction, while the random pore model (RPM) developed by Bhatia and Perlmutter [14] as well as Gavalas [15] is supported as being appropriate for application. This model accounting for the effects of pore growth and coalescence has often shown satisfactory agreement between theory and experiment.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

The combustion reactivity of coal chars in oxyfuel atmosphere: Comparison of different random pore models

Fei

Sun

et al. 2011

Journal of Analytical and Applied Pyrolysis

View full text Add to dashboard Cite

“…(12). This expectation is supported by the data within the limits of experimental error, as shown in Fig.…”

Section: Characteristics Of Parameter and Trpmsupporting

confidence: 72%

Section: Characteristics Of Parameter and Trpmmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

The combustion reactivity of coal chars in oxyfuel atmosphere: Comparison of different random pore models

Fei

Sun

et al. 2011

Journal of Analytical and Applied Pyrolysis

View full text Add to dashboard Cite

“…A random pore model was also proposed by Hashimoto and Silveston (1973) and applied to char gasification. The change in the pore structure is described by a population balance equation involving five to ten parameters.…”

Section: Conclusion and Significancementioning

confidence: 99%

A random capillary model with application to char gasification at chemically controlled rates

1980

View full text Add to dashboard Cite

Porous particles are described by a random capillary model predicting the frequency of pore intersections and the evolution of pore volume and surface area during reaction. The model is applied to char gasification at chemically controlled rates, and the results are compared with data from the literature. GEORGE R. GAVALAS Division of Chemistry ond Chemical EngineeringCalifornia Institute of Technology Pasadena, California 91 125 SCOPERandom capillary models have been used widely to describe catalytic and noncatalytic reactions in porous particles. In these applications, it has not been necessary to precisely elaborate the random nature of the capillary structure. In particular, the overlap volume and number of intersections between different capillaries was either ignored or treated in an ad hoc fashion. Overlap volume is the key concept for describing the changing pore volume and surface area in reactions such as char gasification. Likewise, the frequency of intersections is often required to describe mass transfer in coals and chars when an effective diffusivity is not applicable.In this paper, we develop a random capillary model in which number of intersections, length of pore segments and evolution of pore volume and surface area are exactly and consistently derived from a single probability-density function characterizing the porous solid. As an application of the model, we analyze the gasification of char by oxygen or other gases under conditions of chemical control of the reaction rate. An expression is obtained for the conversion-time curve which clearly displays the effects of surface reaction rate and porous structure. In addition to these model-specific results, we obtain some general model-independent results concerning char conversion. Both the model dependent and the general results are compared with experimental data from the literature.The random capillary model which is here applied and tested for chemically controlled reaction rates could be applied to char reactions involving diffisional limitations. However, the resulting equations would require numerical solution. In all applications, the assumption of constant reactivity of the, pore surface should be kept in mind. This assumption should be further tested experimentally. A simple application of the random model to coal pyrolysis was given recently by Gavalas and Wilks (1979). CONCLUSIONS AND SIGNIFICANCEA random capillary model has been developed describing the porous medium by a single density function A(@, related but not identical to the customary pore size distribution. Precise expressions are derived for the number of intersections between pores of different sizes, the lengths of the pore segments between intersections and the evolution of pore volume and surface area accompanying pore enlargement by reaction.An application to char gasification by oxygen (or carbon dioxide, water, hydrogen) is considered under two assumptions: no diffusional limitations and no dependence of the intrinsic surface reaction rate on conversion. First some ...

show abstract

“…The growth of pore-radius converts the reaction from the diffusion control regime at initial activation times into a kinetic control regime at final times. The effect of this phenomenon was incorporated in the random pore model by using changing parameters computed from the estimated pore size distribution at each time and from integral equations (20)(21)(22)(23)(24)(25).…”

Section: -The Diffusion In Small Pores Is Of Knudsen Typementioning

confidence: 99%

Experimental investigation and mathematical modeling of physical activated carbon preparation from pistachio shell

Faramarzi

Kaghazchi

Ebrahim

et al. 2015

Journal of Analytical and Applied Pyrolysis

View full text Add to dashboard Cite

Gasification: Part I. Isothermal, kinetic control model for a solid with a pore size distribution

Cited by 95 publications

References 22 publications

The combustion reactivity of coal chars in oxyfuel atmosphere: Comparison of different random pore models

The combustion reactivity of coal chars in oxyfuel atmosphere: Comparison of different random pore models

A random capillary model with application to char gasification at chemically controlled rates

Experimental investigation and mathematical modeling of physical activated carbon preparation from pistachio shell

Contact Info

Product

Resources

About