Comparison of global models of sub-bituminous coal devolatilization by means of thermogravimetric analysis

Abstract

Coal gasification and combustion are strongly dependent on devolatilization step. Aim of this work is to obtain the parameters of global kinetics of devolatilization of a sub-bituminous coal with high sulfur content. The kinetic parameters are obtained by means of TG experimental data, and applying different approaches to extrapolate the data to industrial relevant conditions. The simpler method is a model-free one which supposes a single step process whose Arrhenius kinetic parameters (A and Ea) have to be determined. Another common approach is the distributed activation energy model (DAEM) which assumes a series of first order parallel reactions occurring and sharing the same pre-exponential factor, A, with a continuous distribution of the activation energy. For the fitting of the experimental data, a numerical solution to DAEM and two approximate methods have been evaluated. Moreover, the results of these kinetic methods based on empirical approaches were compared with simulated data obtained using a more complex model based on percolation theory with cross-linking mechanism and vapor-liquid equilibrium (chemical percolation devolatilization, CPD model), which allows to simulate the coal pyrolysis from volatile yield data. © 2014 Akadémiai Kiadó, Budapest, Hungary

Double Distribution Activation Energy Model as Suitable Tool in Explaining Biomass and Coal Pyrolysis Behavior

“…This behavior can be explained by considering that the Sulcis coal macromolecule is composed by functional groups and aromatic and hydroaromatic clusters linked by aliphatic bridges. During the pyrolysis, the functional groups are decomposed to form light gas, and the aliphatic bridges, which are weaker than the aromatic ones, are broken producing lighter fragments (tar) [29]. These fragments extract hydrogen from the hydroaromatic and aliphatic groups increasing the aromatic carbon content of the initial coal.…”

CFD Analysis of Co-firing of Coke and Biomass in a Parallel Flow Regenerative Lime Kiln

“…The devolatilization of both coal and biomass particles is modeled assuming that all devolatilization process occurs in one step according to the reaction [47]:…”

Pyrolysis characteristics and kinetics of two Chinese low-rank coals

“…As the pyrolysis is the first step in all thermochemical coal conversion processes, ''key technologies and demonstration on clean and efficient utilization of low-rank coal,'' which was put forward by Chinese Academy of Sciences, aim to make some development in low-rank coal pyrolysis in the forerunner of the comprehensive utilization. Although much work has been conducted to study coal pyrolysis [2][3][4], few studies on pyrolysis mechanism of low-rank coal have been conducted. Therefore, it is necessary to establish the mechanism function and kinetic parameters of low-rank coals.…”

“…Nonisothermal method can be divided into derivative method and integral method according to the form of the kinetic equation [10]. Many works have focused on using single non-isothermal method kinetics model to study coal thermal decomposition [11][12][13][14], and there is still necessary to compare the two non-isothermal methods to decide which one is more adaptive for describing the pyrolysis of coal. This paper aims to compare the kinetic parameters calculated for the pyrolysis of Chinese low-rank coals by using three non-isothermal experimental method including a derivative method and two integral methods, applying the same data treatment in both cases.…”