Added value for forest industry for metals producing and processing integrates (FOR&MET):project report of University of Oulu

Preface This report covers the studies related to biochar characterization and use in blast furnace injection. The research was carried out by Processing Metallurgy Research Unit (University of Oulu) as part of the Added Value for Forest Industry for Metals Producing and Process Integrates (FOR&MET) project. University of Oulu and Technical Research Centre of Finland (VTT) were the research partners in the project. The activities of Technical Research Centre of Finland have been reported in a separate report. We would like to sincerely thank Business Finland for financing the project. We would also like to acknowledge the project partners from industry — SSAB Raahe, Finnpulp Oy, St1 Biofuels Oy and Valmet — for very valuable cooperation and discussion during the project

A thermogravimetric analysis of lignin char combustion

Abstract Understanding the combustion behavior is the basic requirement for a new resource to be used as an alternative fuel for the industrial design of the future plants. In this article, thermogravimetric analysis (TGA) of lignin char combustion in different heating rates (5, 10 and 15 °C/min) was investigated. Extracted combustion indices showed increased weight loss rate, peak temperature and burnout temperature but no change in ignition temperature for all samples when the heating rate increased. Lignin chars containing higher volatile material illustrated higher combustibility through the low ignition and burnout temperatures. Kinetic parameters of lignin combustion were also obtained by the Coat-Redfern method in the first-order kinetic model. High combustibility of high volatile sample (L300: vol%=41) was also confirmed by its low activation energy which was 46.68 compared to 150.34 for L500 (vol%=18) and 174.37 kJ/mol for L650 (vol%=5.1). The pre-exponential factor was also measured to be 2.61E-01, 8.15E+06 and 1.21E+08 min-1for L300, L500 and L650 respectively

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

Abstract 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