Jouni Tummavuori , Hannu Venäläinen, Timo Nyrönen

Termogravimetrian kaytto kiinteiden polttoaineiden tutkimuksissa. Osa VIII. Massan ja lampötilan nostonopeuden vaikutus kineettisten suureiden arvoihin

Tummavuori J., Venäläinen H., Nyrönen T. Termogravimetrian kaytto kiinteiden polttoaineiden tutkimuksissa. Osa VIII. Massan ja lampötilan nostonopeuden vaikutus kineettisten suureiden arvoihin.

Tiivistelmä

We have investigated the influence of the sample mass and the temperature rate on the values of thermogravimetric quantities. The substances used were powdered willow dust and calcium oxalate, since willow dust represents a relatively homogenous natural material whereas calcium oxalate is a very common reference material in thermogravimetric studies. The temperature rate was varied from 0.5 °C • min-1 up to 100 °C • min-1 and the masses were ranging from 10 mg to 420 mg. It is a widely adapted impression that a relatively large masses (several hundred milligrams) and a slow temperature rate (optimum 3 °C • min-1 give the best experimental repetition and correct results. We conclude, however, that the variation in sample masses and in temperature rate in this experiment had no significant influence on. the kinetic quantities computed. The deviations originate from the differences in the instrumental technique and this assesses a requirement for the improved instrumentation before the mathematical relationships between various quantities can be established. Furthermore, the neglible small effect of the reaction order on the kinetic quantities was observed. This was rather surprising, because it was only partly expected due to the formulation of the basic expressions.

Vastaanotettu 31.10.2017 Julkaistu 1.1.1983

Katselukerrat 658

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