CO2 gasification of chars prepared from wood and forest residue: A kinetic study

Liang Wang, Judit Sandquist, G. Várhegyi, Berta Matas Güell

Research output: Article

27 Citations (Scopus)

Abstract

The CO2 gasification of chars prepared from Norway spruce and its forest residue was investigated in a thermogravimetric analyzer (TGA) at slow heating rates. The volatile content of the samples was negligible; hence the gasification reaction step could be studied alone, without the disturbance of the devolatilization reactions. Six TGA experiments were carried out for each sample with three different temperature programs in 60 and 100% CO2. Linear, modulated, and constant-reaction rate (CRR) temperature programs were employed to increase the information content available for the modeling. The temperatures at half of the mass loss were lower in the CRR experiments than in the other experiments by around 120 C. A relatively simple, well-known reaction kinetic equation described the experiments. The dependence on the reacted fraction as well as the dependence on the CO2 concentration were described by power functions (n-order reactions). The evaluations were also carried out by assuming a function of the reacted fraction that can mimic the various random pore/random capillary models. These attempts, however, did not result in an improved fit quality. Nearly identical activation energy values were obtained for the chars made from wood and forest residues (221 and 218 kJ/mol, respectively). Nevertheless, the forest residue char was more reactive; the temperatures at half of the mass loss showed 20-34 C differences between the two chars at 10 C/min heating rates. The assumption of a common activation energy, E, and a common reaction order, ν, on the CO2 concentration for the two chars had only a negligible effect on the fit quality.

Original languageEnglish
Pages (from-to)6098-6107
Number of pages10
JournalEnergy and Fuels
Volume27
Issue number10
DOIs
Publication statusPublished - okt. 17 2013

Fingerprint

Gasification
Wood
Kinetics
Heating rate
Reaction rates
Activation energy
Experiments
Temperature
Reaction kinetics

ASJC Scopus subject areas

  • Chemical Engineering(all)
  • Energy Engineering and Power Technology
  • Fuel Technology

Cite this

CO2 gasification of chars prepared from wood and forest residue : A kinetic study. / Wang, Liang; Sandquist, Judit; Várhegyi, G.; Matas Güell, Berta.

In: Energy and Fuels, Vol. 27, No. 10, 17.10.2013, p. 6098-6107.

Research output: Article

Wang, Liang ; Sandquist, Judit ; Várhegyi, G. ; Matas Güell, Berta. / CO2 gasification of chars prepared from wood and forest residue : A kinetic study. In: Energy and Fuels. 2013 ; Vol. 27, No. 10. pp. 6098-6107.
@article{9598f3c9e20647f78f5ec6f7adf7c783,
title = "CO2 gasification of chars prepared from wood and forest residue: A kinetic study",
abstract = "The CO2 gasification of chars prepared from Norway spruce and its forest residue was investigated in a thermogravimetric analyzer (TGA) at slow heating rates. The volatile content of the samples was negligible; hence the gasification reaction step could be studied alone, without the disturbance of the devolatilization reactions. Six TGA experiments were carried out for each sample with three different temperature programs in 60 and 100{\%} CO2. Linear, modulated, and constant-reaction rate (CRR) temperature programs were employed to increase the information content available for the modeling. The temperatures at half of the mass loss were lower in the CRR experiments than in the other experiments by around 120 C. A relatively simple, well-known reaction kinetic equation described the experiments. The dependence on the reacted fraction as well as the dependence on the CO2 concentration were described by power functions (n-order reactions). The evaluations were also carried out by assuming a function of the reacted fraction that can mimic the various random pore/random capillary models. These attempts, however, did not result in an improved fit quality. Nearly identical activation energy values were obtained for the chars made from wood and forest residues (221 and 218 kJ/mol, respectively). Nevertheless, the forest residue char was more reactive; the temperatures at half of the mass loss showed 20-34 C differences between the two chars at 10 C/min heating rates. The assumption of a common activation energy, E, and a common reaction order, ν, on the CO2 concentration for the two chars had only a negligible effect on the fit quality.",
author = "Liang Wang and Judit Sandquist and G. V{\'a}rhegyi and {Matas G{\"u}ell}, Berta",
year = "2013",
month = "10",
day = "17",
doi = "10.1021/ef401118f",
language = "English",
volume = "27",
pages = "6098--6107",
journal = "Energy & Fuels",
issn = "0887-0624",
publisher = "American Chemical Society",
number = "10",

}

TY - JOUR

T1 - CO2 gasification of chars prepared from wood and forest residue

T2 - A kinetic study

AU - Wang, Liang

AU - Sandquist, Judit

AU - Várhegyi, G.

AU - Matas Güell, Berta

PY - 2013/10/17

Y1 - 2013/10/17

N2 - The CO2 gasification of chars prepared from Norway spruce and its forest residue was investigated in a thermogravimetric analyzer (TGA) at slow heating rates. The volatile content of the samples was negligible; hence the gasification reaction step could be studied alone, without the disturbance of the devolatilization reactions. Six TGA experiments were carried out for each sample with three different temperature programs in 60 and 100% CO2. Linear, modulated, and constant-reaction rate (CRR) temperature programs were employed to increase the information content available for the modeling. The temperatures at half of the mass loss were lower in the CRR experiments than in the other experiments by around 120 C. A relatively simple, well-known reaction kinetic equation described the experiments. The dependence on the reacted fraction as well as the dependence on the CO2 concentration were described by power functions (n-order reactions). The evaluations were also carried out by assuming a function of the reacted fraction that can mimic the various random pore/random capillary models. These attempts, however, did not result in an improved fit quality. Nearly identical activation energy values were obtained for the chars made from wood and forest residues (221 and 218 kJ/mol, respectively). Nevertheless, the forest residue char was more reactive; the temperatures at half of the mass loss showed 20-34 C differences between the two chars at 10 C/min heating rates. The assumption of a common activation energy, E, and a common reaction order, ν, on the CO2 concentration for the two chars had only a negligible effect on the fit quality.

AB - The CO2 gasification of chars prepared from Norway spruce and its forest residue was investigated in a thermogravimetric analyzer (TGA) at slow heating rates. The volatile content of the samples was negligible; hence the gasification reaction step could be studied alone, without the disturbance of the devolatilization reactions. Six TGA experiments were carried out for each sample with three different temperature programs in 60 and 100% CO2. Linear, modulated, and constant-reaction rate (CRR) temperature programs were employed to increase the information content available for the modeling. The temperatures at half of the mass loss were lower in the CRR experiments than in the other experiments by around 120 C. A relatively simple, well-known reaction kinetic equation described the experiments. The dependence on the reacted fraction as well as the dependence on the CO2 concentration were described by power functions (n-order reactions). The evaluations were also carried out by assuming a function of the reacted fraction that can mimic the various random pore/random capillary models. These attempts, however, did not result in an improved fit quality. Nearly identical activation energy values were obtained for the chars made from wood and forest residues (221 and 218 kJ/mol, respectively). Nevertheless, the forest residue char was more reactive; the temperatures at half of the mass loss showed 20-34 C differences between the two chars at 10 C/min heating rates. The assumption of a common activation energy, E, and a common reaction order, ν, on the CO2 concentration for the two chars had only a negligible effect on the fit quality.

UR - http://www.scopus.com/inward/record.url?scp=84885987092&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84885987092&partnerID=8YFLogxK

U2 - 10.1021/ef401118f

DO - 10.1021/ef401118f

M3 - Article

AN - SCOPUS:84885987092

VL - 27

SP - 6098

EP - 6107

JO - Energy & Fuels

JF - Energy & Fuels

SN - 0887-0624

IS - 10

ER -