A CFD study of biomass pyrolysis in a downer reactor equipped with a novel gas-solid separator-II thermochemical performance and products

Xi Yu; Mohamed Hassan; Raffaella Ocone; Yassir Makkawi

doi:10.1016/j.fuproc.2015.01.002

A CFD study of biomass pyrolysis in a downer reactor equipped with a novel gas-solid separator-II thermochemical performance and products

Xi Yu, Mohamed Hassan, Raffaella Ocone, Yassir Makkawi^*

^*Corresponding author for this work

Research output: Contribution to journal › Article › peer-review

Abstract

A Eulerian-Eulerian CFD model was used to investigate the fast pyrolysis of biomass in a downer reactor equipped with a novel gas-solid separation mechanism. The highly endothermic pyrolysis reaction was assumed to be entirely driven by an inert solid heat carrier (sand). A one-step global pyrolysis reaction, along with the equations describing the biomass drying and heat transfer, was implemented in the hydrodynamic model presented in part I of this study (Fuel Processing Technology, V126, 366-382). The predictions of the gas-solid separation efficiency, temperature distribution, residence time and the pyrolysis product yield are presented and discussed. For the operating conditions considered, the devolatilisation efficiency was found to be above 60% and the yield composition in mass fraction was 56.85% bio-oil, 37.87% bio-char and 5.28% non-condensable gas (NCG). This has been found to agree reasonably well with recent relevant published experimental data. The novel gas-solid separation mechanism allowed achieving greater than 99.9% separation efficiency and < 2 s pyrolysis gas residence time. The model has been found to be robust and fast in terms of computational time, thus has the great potential to aid in future design and optimisation of the biomass fast pyrolysis process.

Original language	English
Pages (from-to)	51-63
Number of pages	13
Journal	Fuel Processing Technology
Volume	133
Early online date	23 Jan 2015
DOIs	https://doi.org/10.1016/j.fuproc.2015.01.002
Publication status	Published - May 2015

Bibliographical note

NOTICE: this is the author’s version of a work that was accepted for publication in Fuel processing technology. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Yu, X, Hassan, M, Ocone, R & Makkawi, Y, 'A CFD study of biomass pyrolysis in a downer reactor equipped with a novel gas–solid separator-II: thermochemical performance and products' Fuel processing technology, vol. 133 (2015) DOI http://dx.doi.org/10.1016/j.fuproc.2015.01.002

Funding: Leverhulme Trust grant (RPG-410)

Keywords

biomass
CFD modeling
downer reactor
fast pyrolysis

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10.1016/j.fuproc.2015.01.002

CFD study of biomass pyrolysis in a downer reactor equipped with a novel gas–solid separator-II
NOTICE: this is the author’s version of a work that was accepted for publication in Fuel processing technology. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Yu, X, Hassan, M, Ocone, R & Makkawi, Y, 'A CFD study of biomass pyrolysis in a downer reactor equipped with a novel gas–solid separator-II: thermochemical performance and products' Fuel processing technology, vol. 133 (2015) DOI http://dx.doi.org/10.1016/j.fuproc.2015.01.002
Accepted author manuscript, 1.02 MB

Cite this

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title = "A CFD study of biomass pyrolysis in a downer reactor equipped with a novel gas-solid separator-II thermochemical performance and products",

abstract = "A Eulerian-Eulerian CFD model was used to investigate the fast pyrolysis of biomass in a downer reactor equipped with a novel gas-solid separation mechanism. The highly endothermic pyrolysis reaction was assumed to be entirely driven by an inert solid heat carrier (sand). A one-step global pyrolysis reaction, along with the equations describing the biomass drying and heat transfer, was implemented in the hydrodynamic model presented in part I of this study (Fuel Processing Technology, V126, 366-382). The predictions of the gas-solid separation efficiency, temperature distribution, residence time and the pyrolysis product yield are presented and discussed. For the operating conditions considered, the devolatilisation efficiency was found to be above 60% and the yield composition in mass fraction was 56.85% bio-oil, 37.87% bio-char and 5.28% non-condensable gas (NCG). This has been found to agree reasonably well with recent relevant published experimental data. The novel gas-solid separation mechanism allowed achieving greater than 99.9% separation efficiency and < 2 s pyrolysis gas residence time. The model has been found to be robust and fast in terms of computational time, thus has the great potential to aid in future design and optimisation of the biomass fast pyrolysis process.",

keywords = "biomass, CFD modeling, downer reactor, fast pyrolysis",

author = "Xi Yu and Mohamed Hassan and Raffaella Ocone and Yassir Makkawi",

note = "NOTICE: this is the author{\textquoteright}s version of a work that was accepted for publication in Fuel processing technology. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Yu, X, Hassan, M, Ocone, R & Makkawi, Y, 'A CFD study of biomass pyrolysis in a downer reactor equipped with a novel gas–solid separator-II: thermochemical performance and products' Fuel processing technology, vol. 133 (2015) DOI http://dx.doi.org/10.1016/j.fuproc.2015.01.002 Funding: Leverhulme Trust grant (RPG-410)",

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AU - Yu, Xi

AU - Hassan, Mohamed

AU - Ocone, Raffaella

AU - Makkawi, Yassir

N1 - NOTICE: this is the author’s version of a work that was accepted for publication in Fuel processing technology. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Yu, X, Hassan, M, Ocone, R & Makkawi, Y, 'A CFD study of biomass pyrolysis in a downer reactor equipped with a novel gas–solid separator-II: thermochemical performance and products' Fuel processing technology, vol. 133 (2015) DOI http://dx.doi.org/10.1016/j.fuproc.2015.01.002 Funding: Leverhulme Trust grant (RPG-410)

PY - 2015/5

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N2 - A Eulerian-Eulerian CFD model was used to investigate the fast pyrolysis of biomass in a downer reactor equipped with a novel gas-solid separation mechanism. The highly endothermic pyrolysis reaction was assumed to be entirely driven by an inert solid heat carrier (sand). A one-step global pyrolysis reaction, along with the equations describing the biomass drying and heat transfer, was implemented in the hydrodynamic model presented in part I of this study (Fuel Processing Technology, V126, 366-382). The predictions of the gas-solid separation efficiency, temperature distribution, residence time and the pyrolysis product yield are presented and discussed. For the operating conditions considered, the devolatilisation efficiency was found to be above 60% and the yield composition in mass fraction was 56.85% bio-oil, 37.87% bio-char and 5.28% non-condensable gas (NCG). This has been found to agree reasonably well with recent relevant published experimental data. The novel gas-solid separation mechanism allowed achieving greater than 99.9% separation efficiency and < 2 s pyrolysis gas residence time. The model has been found to be robust and fast in terms of computational time, thus has the great potential to aid in future design and optimisation of the biomass fast pyrolysis process.

AB - A Eulerian-Eulerian CFD model was used to investigate the fast pyrolysis of biomass in a downer reactor equipped with a novel gas-solid separation mechanism. The highly endothermic pyrolysis reaction was assumed to be entirely driven by an inert solid heat carrier (sand). A one-step global pyrolysis reaction, along with the equations describing the biomass drying and heat transfer, was implemented in the hydrodynamic model presented in part I of this study (Fuel Processing Technology, V126, 366-382). The predictions of the gas-solid separation efficiency, temperature distribution, residence time and the pyrolysis product yield are presented and discussed. For the operating conditions considered, the devolatilisation efficiency was found to be above 60% and the yield composition in mass fraction was 56.85% bio-oil, 37.87% bio-char and 5.28% non-condensable gas (NCG). This has been found to agree reasonably well with recent relevant published experimental data. The novel gas-solid separation mechanism allowed achieving greater than 99.9% separation efficiency and < 2 s pyrolysis gas residence time. The model has been found to be robust and fast in terms of computational time, thus has the great potential to aid in future design and optimisation of the biomass fast pyrolysis process.

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KW - downer reactor

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JO - Fuel Processing Technology

JF - Fuel Processing Technology

ER -

A CFD study of biomass pyrolysis in a downer reactor equipped with a novel gas-solid separator-II thermochemical performance and products

Abstract

Bibliographical note

Keywords

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