Torrefaction influence on combustion kinetics of Malaysian oil palm wastes

Abstract

The use of renewable energy has increased in the last decades including the consumption of biofuels, so the research focused on improving these energetic vectors has increased too, developing techniques that enhance energetic properties of these fuels. In this context, torrefaction is a thermal pre-treatment that diminishes the main disadvantages present in biomass such as hygroscopicity, low calorific value per unit mass and high susceptibility to self-ignition. In this study raw and torrefied palm oil wastes samples are tested using thermogravimetric analysis (TGA) in order to study the influence of torrefaction on combustion kinetic parameters using Coats-Redfern and Freeman-Carroll methods, showing that torrefaction increases activation energy as it enhances thermal stability of the samples. The composition of the samples is also estimated using TGA through Fraser-Suzuki deconvolution showing the changes of lignin, cellulose, and hemicellulose due to torrefaction process.

Kinetic Mechanisms and Emissions Investigation of Torrefied Pine Sawdust Utilized as Solid Fuel by Isothermal and Non-Isothermal Experiments

“…Kinetics mechanism provide valuable information for designing and optimizing the combustion facilities. In this study, model fitting methods of an integral method (Coats–Redfern method, CR) [ 35 , 36 , 37 ] and differential method (Freeman–Carroll, FC) [ 16 , 38 ] were employed for calculation of kinetics parameters using TGA data. The conversion rates of all reactions can be described by Arrhenius expression: where α is the conversion degree defined as ( m 0 − m t )/( m 0 − m f ); m 0 is the initial mass of the sample, g; m t is the mass of the sample at time t , g; m f is the final mass of the sample, g; E a is the apparent activation energy (kJ/mol); A is the pre-exponential factor (s −1 ); R is the universal gas constant; T is the temperature (K).…”

“…Investigation of kinetics is the fundament to reveal the combustion mechanisms and to provide references for designing industrial facilities. Thermogravimetric analysis (TGA) has been proved to be an effective method to understand the combustion mechanism of solid fuels [ 16 ]. Ignition temperature ( T i ), burnout temperature ( T p ) etc.…”

“…In addition, few studies researched the kinetic mechanisms of torrefied biomass. Torrefaction was found to increase the activation energy ( E a ) and enhance the thermal stability of oil palm wastes [ 16 ], whereas it decreased the E a of the spent coffee grounds and pigeon pea stalk [ 20 , 21 ]. However, Gürel et al [ 22 ] reported that the torrefied biomass fuels exhibited the same qualitative behavior as the raw fuels.…”

Comparison of Artificial Intelligence Models to Predict Oil Palm Biomass Pyrolysis and Kinetics Using Thermogravimetric Analysis

“…Model-fitting method such as the Coats-Redfern method is utilised as well with the added benefit of being able to hypothesize reaction mechanisms for the process. For example, Castells et al (2021) presented a preliminary view that empty fruits bunch (EFB) samples showed a better fit for the diffusion reactions, while oil palm shell (OPS) and palm mesocarp fibre (PMF) could better fit n-order reactions under a combustion scheme. Surahmanto et al (2020) applied the Coats-Redfern integral method for kinetic analysis of oil palm waste and found that they are best fitted to first-order reactions in the pyrolysis scheme.…”

Solid Fraction of Digestate from Biogas Plant as a Material for Pellets Production

“…The second most important factor is the legal regulations related to environmental protection [3]. One of the renewable energy sources are biofuels produced from biomass [4,5]. Depending on the physical state of the final product, it is possible to distinguish solid [6,7], liquid [8], and gaseous biofuels [9,10].…”