CO2 gasification of char derived from waste tire pyrolysis: Kinetic models comparison. (1st August 2020)

• Record Type: Journal Article
• Authors: Betancur, Mariluz; Natalia Arenas, Cindy; Daniel Martínez, Juan; Victoria Navarro, María; Murillo, Ramón
• Is Part Of: Fuel. Volume 273(2020)
• Publication Date: 2020-08-01
• Subjects: Char -- Gasification -- Kinetic models -- Waste tire; Fuel -- Periodicals; Coal -- Periodicals; Coal; Fuel; Periodicals; 662.6
• DOI: 10.1016/j.fuel.2020.117745
• Languages: English
• ISSNs: 0016-2361

Abstract

Highlights: Thermogravimetric runs were conducted at intrinsic chemical reaction conditions. All models predict the conversion ( X ) versus time ( t ) curve. The HMRPM represents entirely how reaction rate decreased ( dX/dt ) with conversion ( X ). The dX/dt vs. X curve is important when the process is being designed and scaled-up. This is the first time that HMRPM is used to describe the pCB gasification with CO2. Abstract: This work studies the gasification of char derived from waste tire pyrolysis (pCB) by using a thermogravimetric analyzer under CO2 /N2 atmospheres (20/80, 25/85 and 30/70 vol%) at different temperatures (825 °C, 850 °C, 875 °C, 900 °C and 925 °C). The main goal is the assessment of three different kinetic models for predicting not only the conversion ( X ) versus time ( t ) curve, but also the reaction rate ( dX/dt ) versus conversion ( X ) one, with high accuracy. At this respect, the Changing Grain Size Model (CGSM), the Random Pore Model (RPM) and a new model based on the RPM named the Hybrid Modified Random Pore Model (HMRPM) were used. The three models were fitted and the kinetic parameters such as the apparent kinetic constant (Ki (T, pj )), the reaction order ( n ), the activation energy ( Ea ) and the pre-exponential factor ( A ) were determined. The results suggest that the HMRPM is the model with better fitting because its ability to reproduce both conversion ( X ) and reaction rate ( dX/dt ); and hence, it is reliable to be integrated in both particle and reactor models, i.e. when the process is being designed and scaled-up. A drastically decrease in the reaction rate at the first stage of conversion (<20%) suggests a possible effect of volatile matter and inorganic compounds contained into the pCB. The n, Ea and A were found to be 0.543, 147.27 kJ/mol and 4.547 × 10 5 s −1, respectively.