University of Oulu

Najibeh Toloue Farrokh, Hannu Suopajärvi, Olli Mattila, Kentaro Umeki, Aekjuthon Phounglamcheik, Henrik Romar, Petri Sulasalmi, Timo Fabritius, Slow pyrolysis of by-product lignin from wood-based ethanol production– A detailed analysis of the produced chars, Energy, Volume 164, 2018, Pages 112-123, ISSN 0360-5442,

Slow pyrolysis of by-product lignin from wood-based ethanol production : a detailed analysis of the produced chars

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Author: Farrokh, Najibeh Toloue1; Suopajärvi, Hannu1; Mattila, Olli2;
Organizations: 1Process Metallurgy Research Unit, University of Oulu, P.O. Box 4300, FI-90014, Oulu, Finland
2SSAB Europe Raahe Steel Plant, Finland
3Energy Engineering, Division of Energy Science, Luleå University of Technology, SE-971 87, Luleå, Sweden
4Research Unit of Sustainable Chemistry, University of Oulu, P.O. Box 3000, FI-90014, Oulu, Finland
Format: article
Version: accepted version
Access: open
Online Access: PDF Full Text (PDF, 1.9 MB)
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Language: English
Published: Elsevier, 2018
Publish Date: 2020-08-22


Slow pyrolysis as a method of producing a high-quality energy carrier from lignin recovered from wood-based ethanol production has not been studied for co-firing or blast furnace (BF) applications up to now. This paper investigates fuel characteristics, grindability, moisture uptake and the flow properties of lignin chars derived from the slow pyrolysis of lignin at temperatures of 300, 500 and 650 °C (L300, L500 and L650 samples respectively) at a heating rate of 5 °C min−1. The lignin chars revealed a high mass and energy yield in the range of 39–73% and 53–89% respectively. Pyrolysis at 500 °C or higher, yielded lignin chars with low H/C and O/C ratios suitable for BF injection. Furthermore, the hydrophobicity of lignin was improved tremendously after pyrolysis. Pyrolysis at high temperatures increased the sphericity of the lignin char particles and caused some agglomeration in L650. Large and less spherical particles were found to be a reason for high permeability, compressibility and cohesion of L300 in contrast to L500 and L650. L300 and L500 chars demonstrated high combustibility with low ignition and burnout temperatures. Also, rheometric analysis showed that L500 has the best flow properties including low aeration energy and high flow function.

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Series: Energy
ISSN: 0360-5442
ISSN-E: 0360-5442
ISSN-L: 0360-5442
Volume: 164
Pages: 112 - 123
DOI: 10.1016/
Type of Publication: A1 Journal article – refereed
Field of Science: 215 Chemical engineering
Funding: This research was conducted as a part of the RENEPRO project (20200224) funded by Interreg Nord (Luleå, Sweden) and FORMET (7182/31/2016) funded by Tekes (the Finnish Funding Agency for Innovation).
Copyright information: © 2018. This manuscript version is made available under the CC-BY-NC-ND 4.0 license