Comparison of kinetic models for isothermal CO2 gasification of coal char-biomass char blended char

Abstract

This study investigated the isothermal gasification reactivity of biomass char (BC) and coal char (CC) blended at mass ratios of 1:3, 1:1, and 3:1 via isothermal thermogravimetric analysis (TGA) at 900, 950, and 1000°C under CO 2 . With an increase in BC blending ratio, there were an increase in gasification rate and a shortening of gasification time. This could be attributed to the high specific surface area of BC and the high uniformity of carbon structures in CC when compared to those in BC. Three representative gas-solid kinetic models, namely, the volumetric model (VM), grain model (GM), and random pore model (RPM), were applied to describe the reaction behavior of the char. Among them, the RPM model was considered the best model to describe the reactivity of the char gasification reaction. The activation energy of BC and CC isothermal gasification as determined using the RPM model was found to be 126.7 kJ/mol and 210.2 kJ/mol, respectively. The activation energy was minimum (123.1 kJ/mol) for the BC blending ratio of 75%. Synergistic effect manifested at all mass ratios of the blended char, which increased with the gasification temperature.

Investigation of parameters influencing gas production and gasification kinetics of Ziguinchor biomass

“…The char kinetic conversions have been the subject of many studies as they are of crucial importance in describing the evolution of char conversion (Li et al, 2017;Hernowo et al, 2022;Ansoumane et al, 2018;Zuo et al, 2015). The gasification kinetics of the char remains complex, when it is linked to several parameters defining the structure and char composition; for example the nature of the char (granulometry, porosity, chemical composition, dispersion of minerals in the char, etc).…”

“…Therefore, it is still difficult to establish a universal mathematical expression to describe the gasification kinetics of the char, however we will use the most widely used models in the literature. Models are developed as research progresses, but each model is valid and practical on a case-by-case basis (Zuo et al, 2015). It has been described in the literature (Schneider et al, 2021;Wang et al, 2016) that each model gives its own interpretation of the kinetics of the char during thermochemical transformation.…”

Kinetic study of the CO2 gasification of manure samples

“…According to the literature [29][30][31], the volumetric model (VM), the shrinking core model (SCM) and the random pore model (RPM) are the three most popular models used to define f(x). These models are based on phenomenological aspects of the gasification process by taking into account different assumptions.…”

“…These models are based on phenomenological aspects of the gasification process by taking into account different assumptions. Volumetric model (VM) assumes a homogeneous reaction throughout the particle and a linear decrease in the reaction surface area with conversion [29]. On the other hand, shrinking core model (SCM) and random pore model (RPM) describe the evolution of the solid structure with the conversion.…”

Thermal pyrolysis and kinetic parameter determination of mango leaves using common and new proposed parallel kinetic models

“…Up to date, the previous studies that implemented these modied models for studying the kinetic parameters focused only on both the combustion of raw materials, [30][31][32] combustion of char 33,34 and char gasication. 27,29,35 In our previously published article, 36 the effect of CO 2 and H 2 O on the reactivity and kinetic behavior of rice straw and sawdust raw pellets oxy-steam combustion was investigated using the three parallel models including the DVM model. In the present study, we planned to apply these parallel models to calculate the chemical kinetics for the pyrolysis process.…”