Test in argon at atmospheric pressure

The tests were carried out in argon atmosphere at 1 bar pressure and a flow rate of 5 cmVmin. The sample weight was between 1.5 and 4.0 mg. Tbe maxima of energy consumption in the DSC curves lie at temperatures between 448 and 496 °C. The resulting coefficients of the Arrhenius equation calculated according to ASTM E 698-79 and the conversion factor, U, are shown in Table 4-80. 

No correlation could be shown for the activation energy E or the frequency factor A with analytical data. 

Statistical evaluation of the peak maximum temperatures of the distillation bitumens results in means with coefficients of variation V = 1.01 % maximum. When using these means in the calculation, the following average values of the Arrhenius coefficients are found  

When individual data from Table 4-80 are used, the mean for E is insignificantly smaller, but has a significant larger coefficient of variation. There is no significant difference 

If bitumens are regared as model substances for heavy residues, then their Arrhenius coefficients can serve as the basis for the calculation of the kinetics of pyrolysis reactions in thermal conversion processes (thermal cracking, visbreaking, hydrotreating etc.). Integration of the peak areas gives a value for the energy required for pyrolysis reactions. 

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