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Han, Tong
Publications (4 of 4) Show all publications
Han, T., Sophonrat, N., Tagami, A., Sevastyanova, O., Mellin, P. & Yang, W. (2019). Characterization of lignin at pre-pyrolysis temperature to investigate its melting problem. Fuel, 235, 1061-1069
Open this publication in new window or tab >>Characterization of lignin at pre-pyrolysis temperature to investigate its melting problem
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2019 (English)In: Fuel, ISSN 0016-2361, E-ISSN 1873-7153, Vol. 235, p. 1061-1069Article in journal (Refereed) Published
Abstract [en]

Technical lignin particles melt under relatively low temperature. This results in the problem in the continuous feeding and fluidization during lignin pyrolysis, which in turn limits its utilization on a large scale. In this study, two most available types of lignin have been used to investigate the lignin melting problem, which are Kraft lignin (KL) from pulping process and hydrolysis lignin (HL) from bio-ethanol production process. Elemental composition, thermal property and thermally decomposed derivatives of each sample are tested by elemental analyzer, TGA, DSC, and Py-GC/MS. Morphology, structure and crystal change before and after heat treatment are tested by microscopy, FTIR and XRD. All results suggest that lignin structure determines its melting properties. Kraft lignin from pulping process contains a less cross-linked structure. It melts under heating. On the other hand, hydrolysis lignin from hydrolysis process contains a highly crossed-linked and condensed structure. It does not melt before decomposition under heat treatment. Modifying lignin structure is suggested for the resolution of technical lignin melting problem.

Place, publisher, year, edition, pages
ELSEVIER SCI LTD, 2019
Keywords
Kraft lignin (KL), Hydrolysis lignin (HL), Melting properties, Structure
National Category
Materials Engineering
Identifiers
urn:nbn:se:kth:diva-238521 (URN)10.1016/j.fuel.2018.08.120 (DOI)000447791900105 ()
Note

QC 20181106

Available from: 2018-11-06 Created: 2018-11-06 Last updated: 2018-11-06Bibliographically approved
Han, T., Sophonrat, N., Tagami, A., Sevastyanova, O., Mellin, P. & Yang, W. (2019). Characterization of lignin at pre-pyrolysis temperature to investigate its melting problem. Fuel, 235, 1061-1069
Open this publication in new window or tab >>Characterization of lignin at pre-pyrolysis temperature to investigate its melting problem
Show others...
2019 (English)In: Fuel, ISSN 0016-2361, E-ISSN 1873-7153, Vol. 235, p. 1061-1069Article in journal (Refereed) Published
Abstract [en]

Technical lignin particles melt under relatively low temperature. This results in the problem in the continuous feeding and fluidization during lignin pyrolysis, which in turn limits its utilization on a large scale. In this study, two most available types of lignin have been used to investigate the lignin melting problem, which are Kraft lignin (KL) from pulping process and hydrolysis lignin (HL) from bio-ethanol production process. Elemental composition, thermal property and thermally decomposed derivatives of each sample are tested by elemental analyzer, TGA, DSC, and Py-GC/MS. Morphology, structure and crystal change before and after heat treatment are tested by microscopy, FTIR and XRD. All results suggest that lignin structure determines its melting properties. Kraft lignin from pulping process contains a less cross-linked structure. It melts under heating. On the other hand, hydrolysis lignin from hydrolysis process contains a highly crossed-linked and condensed structure. It does not melt before decomposition under heat treatment. Modifying lignin structure is suggested for the resolution of technical lignin melting problem.

Place, publisher, year, edition, pages
Elsevier, 2019
Keywords
Hydrolysis lignin (HL), Kraft lignin (KL), Melting properties, Structure, Crystal structure, Fluidization, Heat treatment, Hydrolysis, Melting, Pulp manufacture, Pyrolysis, Structure (composition), Temperature, After-heat treatment, Bio-ethanol production, Crosslinked structures, Elemental compositions, Hydrolysis lignins, Kraft lignin, Pyrolysis temperature, Lignin
National Category
Chemical Engineering
Identifiers
urn:nbn:se:kth:diva-236342 (URN)10.1016/j.fuel.2018.08.120 (DOI)000447791900105 ()2-s2.0-85052512069 (Scopus ID)
Funder
Swedish Research Council Formas
Note

QC 20181108

Available from: 2018-11-08 Created: 2018-11-08 Last updated: 2018-11-08Bibliographically approved
Han, T., Sophonrat, N., Evangelopoulos, P., Persson, H., Weihong, Y. & Jönsson, P. (2018). Evolution of sulfur during fast pyrolysis of sulfonated Kraft lignin. Journal of Analytical and Applied Pyrolysis, 33, 162-168
Open this publication in new window or tab >>Evolution of sulfur during fast pyrolysis of sulfonated Kraft lignin
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2018 (English)In: Journal of Analytical and Applied Pyrolysis, ISSN 0165-2370, E-ISSN 1873-250X, Vol. 33, p. 162-168Article in journal (Refereed) Published
Abstract [en]

Sulfonated Kraft lignin, the most available commercial lignin of today, has high sulfur content due to the extraction and the subsequent sulfonation processes. In this work, the evolution of sulfur during fast pyrolysis of sulfonated Kraft lignin has been studied. Fast Pyrolysis experiments have been done using Py-GC/MS. It is found that main sulfur-containing products in the pyrolytic vapors are present as the following small molecular compounds: H2S, SO2, CH3SH, CH3SCH3, and CH3SSCH3. This indicates that sulfur-containing radicals preferentially combine with the other small radicals such as H and CH3 during fast pyrolysis process. Sulfur is suggested to be mainly present as sulfite (SO3) and sulfide (S) in the sulfonated Kraft lignin. Sulfite that is incorporated into lignin during the sulfonation process mainly result in the formation of SO2. The nature of the sulfur links created during the Kraft pulping process is difficult to determine, but they are supposed to mainly exist in form of sulfide (S) bonds, which lead to the formation of H2S, CH3SH, CH3SCH3 and CH3SSCH3.

Place, publisher, year, edition, pages
Elsevier, 2018
National Category
Chemical Engineering Materials Engineering
Identifiers
urn:nbn:se:kth:diva-229683 (URN)10.1016/j.jaap.2018.04.006 (DOI)000435747900020 ()2-s2.0-85045121473 (Scopus ID)
Funder
Swedish Research Council Formas
Note

QC 20180611

Available from: 2018-06-05 Created: 2018-06-05 Last updated: 2018-07-23Bibliographically approved
Persson, H., Han, T., Xia, W., Evangelopoulos, P. & Weihong, Y. (2018). Fractionation of liquid products from pyrolysis of lignocellulosic biomass by stepwise thermal treatment. Energy, 154, 346-351
Open this publication in new window or tab >>Fractionation of liquid products from pyrolysis of lignocellulosic biomass by stepwise thermal treatment
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2018 (English)In: Energy, ISSN 0360-5442, E-ISSN 1873-6785, Vol. 154, p. 346-351Article in journal (Refereed) Published
Abstract [en]

The thermal properties of cellulose, hemicellulose and lignin can be utilized to improve the characteristics of pyrolysis liquids. In this study, a concept of stepwise pyrolysis to fractionate the liquid based on the thermal properties of the biomass constituents was investigated. Lignocellulosic biomass was thermally treated in two steps: 200–300 °C followed by 550 °C. Derived liquids were studied for GC/MS analysis, water content, acid concentration and a solvent extraction method. Pyrolytic liquid derived from 550 °C after treatment at lower temperatures have a higher relative composition of phenolic compounds compared to one-step pyrolysis (increased from 58 to 90% of GC/MS peak area). Also, compounds known to promote aging, such as acids and carbonyl compounds, are derived at lower temperatures which may suppress aging in the liquid derived downstream at 550 °C. For liquids derived at 550 °C, the total acid number was reduced from 125 in one-step treatment to 14 in two-step treatment. Overall, no significant difference in the total liquid yield (sum of the liquids derived in separated treatments) nor any variations in their collective composition compared to one-step treatment at 550 °C was observed, i.e. stepwise pyrolysis can be utilized for direct fractionation of pyrolytic vapors.

Place, publisher, year, edition, pages
Elsevier, 2018
Keywords
Pyrolysis Biomass Bio-oil Stepwise Fractionation
National Category
Engineering and Technology
Research subject
Chemical Engineering; Chemistry; Energy Technology; Fibre and Polymer Science
Identifiers
urn:nbn:se:kth:diva-227249 (URN)10.1016/j.energy.2018.04.150 (DOI)000436886200033 ()2-s2.0-85046167007 (Scopus ID)
Funder
Swedish Energy Agency, 33284-2Swedish Energy Agency, 39449-1
Note

QC 20180522

Available from: 2018-05-04 Created: 2018-05-04 Last updated: 2018-07-17Bibliographically approved
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