Kinetics of volatile matter release

Kinetics of Volatile Matter Release from Pennsylvania Anthracites... 

In this paper the kinetics of volatile matter release from anthracites have been studied in some detail. Rates of volatile matter release from different particle sizes of anthracite as a function of heating rate and temperature have been measured. The change in composition of the volatile matter with volatilization temperature has been studied. 

Our primary objective has been to present the experimental results in a convenient, combined form rather than to discuss their significance in great detail. In view of the extreme physical and chemical complexity of anthracite and the limited amount of experimental investigation to which the material has been subjected at present, an elaborate theoretical discussion would be pointless. Indeed, it is improbable that the kinetics of volatile matter release for such a complex material will ever submit to a satisfactory correlation by simple functional relationships. In spite of these difficulties, it is of interest to discuss some of the general trends exhibited by the experimental data and their interpretation by suggesting approximate theoretical and mathematical models for the release mechanism. 

We would agree that grinding should produce some macrocracks in the particles and that these macrocracks can open up previously closed-pore volume. This, in turn, will affect the kinetics of volatile matter release. 

L. L. Newman Dr. Mackowsky has already asked you if you related your studies on the kinetics of volatile matter release from Pennsylvania anthracites to the petrographic constituents of the coal. Can you not say in effect that the coals from the various collieries differ from each other quite significantly with respect to their petrographic composition and that identification of a coal by source may identify it petrographically to some extent How do the results of these studies relate decrepitation actually experienced in industrial operations ... 

Dr. Walker We have not related our studies of kinetics of volatile matter release from anthracites to their petrographic consituents. This type of work is planned for the future. 

Pyrolysis of Biomass The kinetic parameters of the pyrolysis of solid materials can be determined by means of non-isothermal thermogravimetric measurements. The rate of release of volatile matter may be described by a simple first-order expression ... 

The porous carbon, or char, is left after the volatile matter is released from the coal. The combustion of carbon in the gaseous oxygen phase is a complex set of heterogeneous reactions for both the gas and the solid. It may occur on the surface or inside the pores of the char and is controlled by gas diffusion and kinetics, reaction temperature, char structure. Generally, the reactions are expressed by three heterogeneous reactions and one gas-phase reaction. 

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