How can Activation Energy be calculated from a TPR profile data of a sample treated at constant heating rate. Does a shift in a TPR peak imply change in activation energy if the shift occurs at similar heating rates?
If you have experimental data for X(t) and T(t) (X - conversion, T - temperature, t - time) than using model you can get an approximation for activation energy and pre-exponential factor.
For volumetric model and Arrhenius law:
dX/dt=A*exp(-Ea/(R*T))*(1-X)
ln(dX/dt)+ln(X)=ln(A)-Ea/(R*T)
You have 2 variables and as may equations as you have data points.
If the heating rate is constant, any change in peak height, width or position will alter model parameters.
It depends on the type of data you have. That determines the form of the conversion function. Look up these two references and they will help
Kissinger, H.E., Reaction kinetics in differential thermal analysis, Anal. Chem. 29 (1957) 1702-1706.
Friedman, H. L., Kinetics of thermal degradation of char-foaming plastics from thermogravimetry . Application to a phenolic resin, Polym. Sci. 6C (1963) 183-195.
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