If you have the TGA developed and have well identified the peak corresponding to pyrolysis, then you are ready to apply any of the methods stablished. The literature is plenty of them. In all cases are based on adjust of experimental data where the activation energy is deduced throughout the slope of a linear regression of the selected model. You may select one of these: Friedman type, Vyazovkin type, Kissinger or Coats-Redfern (I suggest this). The Ea can be through them estimated but the Ahrrenius factor and the kinetic decomposition mechanism.

Regards

Tomasz Noszczyk

Look at the detailed calculation in the link to the dissertation

file:///C:/Users/Admin/Downloads/Dissertacija_Kozlova_A.N._dlja_razmeshchenija_na_saite.pdf

If you have the TGA data (multiple heating rates or single heating rate) and have well identified the peak corresponding to pyrolysis, then you can select any of the established models such as Friedman, OFW, KAS, Straink, tang model, DAEM model, Vyazovkin type, Kissinger or Coats-Redfern etc,. The TGA data obtained from the experiments fit into these models and you will able to calculate the kinetic parameters such as activation energy, order of reaction and frequency factors.

Here some of the useful link to fully understand the details of pyrolysis kinetics.

Article Pyrolysis kinetics and thermal behavior of waste sawdust bio...

Article Kinetic analysis and pyrolysis behaviour of waste biomass to...

Article Pyrolysis kinetics behaviour and thermal pyrolysis of Samane...

https://link.springer.com/content/pdf/10.1007/s13399-019-00469-3.pdf

Article Pyrolysis kinetic behavior and Py-GC–MS analysis of waste da...

Article Pyrolysis kinetics and synergistic effect in co-pyrolysis of...

Hope you will find some interesting information.

Hello Tomaz,

Leia o review intitulaodo: ICTAC Kinetics Committee recommendations for performing kinetic computations on thermal analysis data que você vai aprender como calcular a energia de ativação e o fator pré-exponencial do processo de pirolysis de seu material

If you need on how to find iso-conversional points, I can help. Selecting the isoconversional points is the most important step followed by the plots where from these linear plots, the activation and frequency factors can be determined.

Read the review entitled: Recommendations of the ICTAC Kinetics Committee to perform kinetic calculations on thermal analysis data that you will learn how to calculate the activation energy and the pre-exponential factor of the pyrolysis process of your material.

For a constant heating rate or single heating rate Coats and Redfern method or the Freeman and Carroll method can be used. for a more accurate kinetics you can vary the heating rates and use either Flynn-Wall-Ozawa (FWO, ASTM E1641) or Kissinger (KAS, ASTM E2890) or Friedman

Please read the paper of Rego et al. Article Pyrolysis kinetics of short rotation coppice poplar biomass

There are several methods. The Kissinger method is easy to apply. You can read our recent paper

Pyrolysis kinetics of short rotation coppice poplar biomass

F Rego, APS Dias, M Casquilho, FC Rosa, A Rodrigues

Energy 207, 118191

You me contact me, on [email protected] to assist you and guide you

Dear Fred.

Jetsada can help to calculate activation energy. Anyway I shall send to you method of calculation we develop in my lab.

All the Best.

There are different methods to calculate the activation energy of a biomass pyrolysis using TGA. The most common methods are KAS, FWO and others.

1- Calculations of conversion degree (alpha) using standard formula

2- Normally the selected values of conversion degree are (0.05, 01, 0.2, 0.3, 0.4, ... 0.9)

3- At different heating rates, the conversion degree is calculated based on initial and final mass of biomass sample.

4- Keeping conversion degree (alpha) constant e.g. 01. or any other values, at all heating values studied , now these values of conversion are called isoconversional points. These points are constant and not changing with heating rates, and are independent of temperature. Now if you have at least 3 heating rates and one value of conversion degree, a plot of ln(heating rate/square of temperature for that conversional point) is plotted against inverse of pyrolysis of temperature. and so on.

Tomasz Noszczyk find attached the chapter 2 of the book Waste Biorefinery-Potential and Perspectives. It discuses extensively how to calculate the kinetics of biomass pyrolysis elaborating on over 20 models that can be used; Diffusion Models, Geometrical Contraction Models, Nucleation or Growth Model, Order Based Models, Single Heating Rate Method, Model Fitting Methods, Isoconversional Methods as well as some other noteworthy methods.