Pyrolysis kinetics of soybean straw using thermogravimetric analysis

• The decomposition zone of soybean straw could be divided into three stages.
• The kinetic of soybean straw pyrolysis was studied by three models.
• Simulation of pyrolysis showed a good agreement with experimental data.
• An insight for future applications of soybean straw was provided.

Thermochemical conversion of crops straw is receiving renewed attention, due to the energy and material recovery that can be achieved. However, it still lacks the kinetic background which is of great importance for a successful design of thermochemical process. In this work, pyrolysis test for soybean straw was performed in a non-isothermal thermogravimetric analysis (TGA) in order to determine the thermal degradation behavior. Pyrolysis experiments were carried out under inert conditions and operated at different heating rates (5, 10, 20, and 30 K/min). Three different kinetic models, iso-conversional Kissinger–Akahira–Sunose (KAS), Ozawa–Flynn–Wall (OFW) models, and Coats–Redfern method were applied on TGA data of soybean straw to calculate the kinetic parameters including activation energy, pre-exponential factor, and reaction order. The activation energy values were 154.15 and 156.22 kJ/mol based on KAS and OFW models, respectively. Simulation of the soybean straw thermal decomposition using the obtained kinetic parameters and comparison with experimental data are in good agreement.