Kinetic Parameters for Biomass under Self-Ignition Conditions: Low-Temperature Oxidation and Pyrolysis

Lars Schwarzer, Zsuzsa Sárossy, Peter Arendt Jensen*, Peter Glarborg, Oskar Karlström, Jens Kai Holm, Kim Dam-Johansen

*Corresponding author for this work

Research output: Contribution to journalJournal articleResearchpeer-review

Abstract

Pulverized biomass may self-heat and spontaneously ignite when stored or processed at intermediate or even low temperatures. In this work, reaction kinetic parameters for biomass oxidation and pyrolysis were determined for the temperature range 423–523 K. Thermogravimetric analysis was used to determine mass loss kinetics in a stepwise-isothermal heating program. Two wood species (pine and beech), two agricultural residues (wheat straw and sunflower husks), and two commercial wood pellet samples were investigated. Atmospheres with 0, 20, and 80% oxygen were used in the experiments. A pyrolysis model of four parallel reactions for extractives, hemicellulose, cellulose, and lignin fit the experimental data for 0% O2 well. Oxidation kinetics could be modeled by additional reactions in parallel to the pyrolysis mechanism. Two mechanisms were tested: (1) considering oxidation of a lumped “volatilizable” component plus oxidation of char; and (2) separate oxidation reactions for volatilizable extractives, hemicellulose, cellulose, and lignin, plus char. The more complex mechanism did not give a clear advantage over the simpler mechanism. It was further found that pyrolysis and oxidation reactions for the components could be modeled with the same activation energy, regardless of which biomass they appear in. For the lumped component oxidation model, an apparent activation energy of 130 kJ/mol was found. The observed reaction order in oxygen was in the range 0.4–0.5. The models also compared favorably to additional experimental data between 373 and 773 K for a heating rate of 5 K/min. The kinetic models presented here are intended mainly to describe low-temperature reactions, such as self-heating of biomass and the onset of smoldering combustion.
Original languageEnglish
JournalEnergy & Fuels
Volume33
Issue number9
Pages (from-to)8606-8619
ISSN0887-0624
DOIs
Publication statusPublished - 2019

Cite this

@article{a66d3a6a048244c9b2e9dc60ece7cc87,
title = "Kinetic Parameters for Biomass under Self-Ignition Conditions: Low-Temperature Oxidation and Pyrolysis",
abstract = "Pulverized biomass may self-heat and spontaneously ignite when stored or processed at intermediate or even low temperatures. In this work, reaction kinetic parameters for biomass oxidation and pyrolysis were determined for the temperature range 423–523 K. Thermogravimetric analysis was used to determine mass loss kinetics in a stepwise-isothermal heating program. Two wood species (pine and beech), two agricultural residues (wheat straw and sunflower husks), and two commercial wood pellet samples were investigated. Atmospheres with 0, 20, and 80{\%} oxygen were used in the experiments. A pyrolysis model of four parallel reactions for extractives, hemicellulose, cellulose, and lignin fit the experimental data for 0{\%} O2 well. Oxidation kinetics could be modeled by additional reactions in parallel to the pyrolysis mechanism. Two mechanisms were tested: (1) considering oxidation of a lumped “volatilizable” component plus oxidation of char; and (2) separate oxidation reactions for volatilizable extractives, hemicellulose, cellulose, and lignin, plus char. The more complex mechanism did not give a clear advantage over the simpler mechanism. It was further found that pyrolysis and oxidation reactions for the components could be modeled with the same activation energy, regardless of which biomass they appear in. For the lumped component oxidation model, an apparent activation energy of 130 kJ/mol was found. The observed reaction order in oxygen was in the range 0.4–0.5. The models also compared favorably to additional experimental data between 373 and 773 K for a heating rate of 5 K/min. The kinetic models presented here are intended mainly to describe low-temperature reactions, such as self-heating of biomass and the onset of smoldering combustion.",
author = "Lars Schwarzer and Zsuzsa S{\'a}rossy and Jensen, {Peter Arendt} and Peter Glarborg and Oskar Karlstr{\"o}m and Holm, {Jens Kai} and Kim Dam-Johansen",
year = "2019",
doi = "10.1021/acs.energyfuels.9b00848",
language = "English",
volume = "33",
pages = "8606--8619",
journal = "Energy & Fuels",
issn = "0887-0624",
publisher = "American Chemical Society",
number = "9",

}

Kinetic Parameters for Biomass under Self-Ignition Conditions: Low-Temperature Oxidation and Pyrolysis. / Schwarzer, Lars; Sárossy, Zsuzsa ; Jensen, Peter Arendt; Glarborg, Peter; Karlström, Oskar ; Holm, Jens Kai; Dam-Johansen, Kim.

In: Energy & Fuels, Vol. 33, No. 9, 2019, p. 8606-8619.

Research output: Contribution to journalJournal articleResearchpeer-review

TY - JOUR

T1 - Kinetic Parameters for Biomass under Self-Ignition Conditions: Low-Temperature Oxidation and Pyrolysis

AU - Schwarzer, Lars

AU - Sárossy, Zsuzsa

AU - Jensen, Peter Arendt

AU - Glarborg, Peter

AU - Karlström, Oskar

AU - Holm, Jens Kai

AU - Dam-Johansen, Kim

PY - 2019

Y1 - 2019

N2 - Pulverized biomass may self-heat and spontaneously ignite when stored or processed at intermediate or even low temperatures. In this work, reaction kinetic parameters for biomass oxidation and pyrolysis were determined for the temperature range 423–523 K. Thermogravimetric analysis was used to determine mass loss kinetics in a stepwise-isothermal heating program. Two wood species (pine and beech), two agricultural residues (wheat straw and sunflower husks), and two commercial wood pellet samples were investigated. Atmospheres with 0, 20, and 80% oxygen were used in the experiments. A pyrolysis model of four parallel reactions for extractives, hemicellulose, cellulose, and lignin fit the experimental data for 0% O2 well. Oxidation kinetics could be modeled by additional reactions in parallel to the pyrolysis mechanism. Two mechanisms were tested: (1) considering oxidation of a lumped “volatilizable” component plus oxidation of char; and (2) separate oxidation reactions for volatilizable extractives, hemicellulose, cellulose, and lignin, plus char. The more complex mechanism did not give a clear advantage over the simpler mechanism. It was further found that pyrolysis and oxidation reactions for the components could be modeled with the same activation energy, regardless of which biomass they appear in. For the lumped component oxidation model, an apparent activation energy of 130 kJ/mol was found. The observed reaction order in oxygen was in the range 0.4–0.5. The models also compared favorably to additional experimental data between 373 and 773 K for a heating rate of 5 K/min. The kinetic models presented here are intended mainly to describe low-temperature reactions, such as self-heating of biomass and the onset of smoldering combustion.

AB - Pulverized biomass may self-heat and spontaneously ignite when stored or processed at intermediate or even low temperatures. In this work, reaction kinetic parameters for biomass oxidation and pyrolysis were determined for the temperature range 423–523 K. Thermogravimetric analysis was used to determine mass loss kinetics in a stepwise-isothermal heating program. Two wood species (pine and beech), two agricultural residues (wheat straw and sunflower husks), and two commercial wood pellet samples were investigated. Atmospheres with 0, 20, and 80% oxygen were used in the experiments. A pyrolysis model of four parallel reactions for extractives, hemicellulose, cellulose, and lignin fit the experimental data for 0% O2 well. Oxidation kinetics could be modeled by additional reactions in parallel to the pyrolysis mechanism. Two mechanisms were tested: (1) considering oxidation of a lumped “volatilizable” component plus oxidation of char; and (2) separate oxidation reactions for volatilizable extractives, hemicellulose, cellulose, and lignin, plus char. The more complex mechanism did not give a clear advantage over the simpler mechanism. It was further found that pyrolysis and oxidation reactions for the components could be modeled with the same activation energy, regardless of which biomass they appear in. For the lumped component oxidation model, an apparent activation energy of 130 kJ/mol was found. The observed reaction order in oxygen was in the range 0.4–0.5. The models also compared favorably to additional experimental data between 373 and 773 K for a heating rate of 5 K/min. The kinetic models presented here are intended mainly to describe low-temperature reactions, such as self-heating of biomass and the onset of smoldering combustion.

U2 - 10.1021/acs.energyfuels.9b00848

DO - 10.1021/acs.energyfuels.9b00848

M3 - Journal article

VL - 33

SP - 8606

EP - 8619

JO - Energy & Fuels

JF - Energy & Fuels

SN - 0887-0624

IS - 9

ER -