The devolatilization is a basic mechanism for all thermochemical processes (pyrolysis, combustion, gasification), especially for biomasses that contain a large amount of volatile matter. Because of the wide variety in origin, structure, and composition, it is desirable to study these renewable fuels starting from their chemical composition, which is referring to the organic fractions of cellulose, hemicellulose, extractives, and lignin. An optimization procedure based on a summative law and first-order reaction model is validated in this work with uniform experimental data on 37 biomasses, such as woods, energy crops, and agricultural and food residues, selected as potential energy sources on a regional scale. The thermogravimetric (TG) weight loss and its derivative (dtg) curves are accurately predicted (discrepancy between 0.4 and 1.4%) in the entire temperature range with kinetic parameters for common biocomponents, defined as the unseparated fractions of the biomasses with the original content of ash. The kinetic parameters obtained are within the ranges of values obtained in the literature for the activation energy of synthesized components. The procedure developed here is also successfully extended to further tests under different heating rates and biomasses outside the data set used for the validation and literature data. Finally, it can be used for obtaining the chemical composition of lignocellulosic materials based on a simple TG run. © 2014 American Chemical Society.
A generalized correlation for coal devolatilization kinetics at high temperature
BIAGINI, ENRICO;TOGNOTTI, LEONARDO
2014-01-01
Abstract
The devolatilization is a basic mechanism for all thermochemical processes (pyrolysis, combustion, gasification), especially for biomasses that contain a large amount of volatile matter. Because of the wide variety in origin, structure, and composition, it is desirable to study these renewable fuels starting from their chemical composition, which is referring to the organic fractions of cellulose, hemicellulose, extractives, and lignin. An optimization procedure based on a summative law and first-order reaction model is validated in this work with uniform experimental data on 37 biomasses, such as woods, energy crops, and agricultural and food residues, selected as potential energy sources on a regional scale. The thermogravimetric (TG) weight loss and its derivative (dtg) curves are accurately predicted (discrepancy between 0.4 and 1.4%) in the entire temperature range with kinetic parameters for common biocomponents, defined as the unseparated fractions of the biomasses with the original content of ash. The kinetic parameters obtained are within the ranges of values obtained in the literature for the activation energy of synthesized components. The procedure developed here is also successfully extended to further tests under different heating rates and biomasses outside the data set used for the validation and literature data. Finally, it can be used for obtaining the chemical composition of lignocellulosic materials based on a simple TG run. © 2014 American Chemical Society.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
