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Håkansson, Helena
Alternative names
Publications (10 of 23) Show all publications
Hashemzehi, M., Sjöstrand, B., Håkansson, H. & Henriksson, G. (2024). Degrees of hornification in softwood and hardwood kraft pulp during drying from different solvents. Cellulose
Open this publication in new window or tab >>Degrees of hornification in softwood and hardwood kraft pulp during drying from different solvents
2024 (English)In: Cellulose, ISSN 0969-0239, E-ISSN 1572-882XArticle in journal (Refereed) Epub ahead of print
Abstract [en]

Hornification, a complex phenomenon occurring during drying of lignocellulosic materials because of formation of irreversible chemical bonds, remains a subject of scientific interest. This study aims to shed light on the underlying mechanisms of hornification by investigating interactions between the liquid and solid phases through a solvent exchange treatment. The treatment involved replacing water with various solvents in suspensions of never-dried cellulose samples, including alcohols (methanol, ethanol, isopropanol) capable of forming hydrogen bonds, albeit to a lesser extent than water, as well as non-alcohol solvents (acetone, ethyl acetate, toluene, heptane) that do not possess the ability to form chain of hydrogen bond, and no hydrogen bond between each other. The impact of solvents on the hornification process was evaluated using WRV measurements. Our findings reveal that water, as a solvent, plays a dominant role in the hornification process, primarily due to its excellent capability to form bridges of hydrogen bonds. In comparison, hornification with alcohols was considerably lower than with water, likely attributed to the smaller ability of alcohols to engage in such interactions. Furthermore, our results indicate a tendency for reduced hornification also when using non-hydrogen bond solvents with decreased polarity. This strengthens the hypothesis related to chains of hydrogen bonds. Additionally, the interaction between hydrophobic surfaces on cellulose through hydrophobic interactions could provide another plausible explanation.

Place, publisher, year, edition, pages
Springer, 2024
Keywords
Cellulose, Hornifcation, Hydrogen bonds, Polarity, Solvent exchange
National Category
Paper, Pulp and Fiber Technology
Research subject
Chemical Engineering
Identifiers
urn:nbn:se:kau:diva-97923 (URN)10.1007/s10570-023-05657-z (DOI)001136057300001 ()2-s2.0-85181484985 (Scopus ID)
Available from: 2024-01-04 Created: 2024-01-04 Last updated: 2024-02-07Bibliographically approved
Witthayolankowit, K., Ramazanova, L., Baddigam, K. R., Marson, A., Apostolopoulou-Kalkavoura, V., Lebedeva, D., . . . Samec, J. S. M. (2023). Valorization of Tops and Branches to Textile Fibers and Biofuel: Value Chain Explored Experimentally; Environmental Sustainability Evaluated by Life Cycle Assessment. ACS Sustainable Chemistry and Engineering, 12(1), 526-533
Open this publication in new window or tab >>Valorization of Tops and Branches to Textile Fibers and Biofuel: Value Chain Explored Experimentally; Environmental Sustainability Evaluated by Life Cycle Assessment
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2023 (English)In: ACS Sustainable Chemistry and Engineering, E-ISSN 2168-0485, Vol. 12, no 1, p. 526-533Article in journal (Refereed) Published
Abstract [en]

To make biorefining more environmentally sustainable, preferably residues from forestry should be used and more than one fraction should be upgraded. A third of raw materials from forestry & horbar;tops and branches (T & B)― are either left in the forests or collected and incinerated to a low value. Herein, we apply a fast fractionation to valorize two of the fractions of this forestry residue. The cellulose is converted to textile fibers and all the lignin to hydrocarbons. The environmental sustainability of the novel value chain was studied by life cycle assessment (LCA), and benefits were found in four out of five impact categories. These are important steps to increase fiber production without affecting environmental impact, making biorefining competitive.

Place, publisher, year, edition, pages
American Chemical Society (ACS), 2023
Keywords
tops and branches, biomass valorization, viscosefibers, jet fuel, life cycle assessment
National Category
Forest Science
Research subject
Chemical Engineering
Identifiers
urn:nbn:se:kau:diva-98224 (URN)10.1021/acssuschemeng.3c06561 (DOI)001138386600001 ()2-s2.0-85181829599 (Scopus ID)
Funder
Region Stockholm, 2018/11Swedish Energy Agency, LM2018119
Available from: 2024-01-29 Created: 2024-01-29 Last updated: 2024-02-02Bibliographically approved
Håkansson, H. (Ed.). (2022). Bidrag från 8:e Utvecklingskonferensen för Sveriges ingenjörsutbildningar. Paper presented at 8:e Utvecklingskonferensen för Sveriges ingenjörsutbildningar, Karlstad 24-25 november 2021. Karlstads universitet
Open this publication in new window or tab >>Bidrag från 8:e Utvecklingskonferensen för Sveriges ingenjörsutbildningar
2022 (Swedish)Conference proceedings (editor) (Refereed)
Abstract [sv]

Utvecklingskonferensen för Sveriges ingenjörsutbildningar är en nationell konferens för ingenjörsutbildning på högskolor och universitet. Konferensens syfte är att utveckla ingenjörsutbildningarnas kvalitet genom att:

  • lyfta fram och dela erfarenheter kring aktuell utveckling av ingenjörsutbildning
  • vara en arena för pedagogisk meritering och över tid utgöra ett arkiv för utvecklingen av Sveriges ingenjörsutbildningar
  • tillsammans analysera nuläge och utveckla nya möjligheter

Den 24 och 25 november 2021 samlades ledare, lärare, studenter och andra personer med intresse för utveckling inom ingenjörsutbildningar för en tvådagarskonferens på Karlstads universitet.

Temat för årets konferens var:Tillsammans förnyar och förbättrar vi Sveriges ingenjörsutbildningar inför framtidens utmaningar

Place, publisher, year, edition, pages
Karlstads universitet, 2022. p. 193
Series
Karlstad University Studies, ISSN 1403-8099 ; 2022:8
National Category
Other Engineering and Technologies not elsewhere specified Educational Sciences
Research subject
Educational Work
Identifiers
urn:nbn:se:kau:diva-89206 (URN)978-91-7867-271-4 (ISBN)978-91-7867-281-3 (ISBN)
Conference
8:e Utvecklingskonferensen för Sveriges ingenjörsutbildningar, Karlstad 24-25 november 2021
Available from: 2022-03-24 Created: 2022-03-24 Last updated: 2022-04-11Bibliographically approved
Adler, A., Kumaniaev, I., Karacic, A., Baddigam, K. R., Hanes, R. J., Subbotina, E., . . . Samec, J. S. .. (2022). Lignin-first biorefining of Nordic poplar to produce cellulose fibers could displace cotton production on agricultural lands. Joule, 6(8), 1845-1858
Open this publication in new window or tab >>Lignin-first biorefining of Nordic poplar to produce cellulose fibers could displace cotton production on agricultural lands
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2022 (English)In: Joule, E-ISSN 2542-4351, Vol. 6, no 8, p. 1845-1858Article in journal (Refereed) Published
Abstract [en]

Here, we show that lignin-first biorefining of poplar can enable the production of dissolving cellulose pulp that can produce regenerated cellulose, which could substitute cotton. These results in turn indicate that agricultural land dedicated to cotton could be reclaimed for food production by extending poplar plantations to produce textile fibers. Based on climate-adapted poplar clones capable of growth on marginal lands in the Nordic region, we estimate an environmentally sustainable annual biomass production of ∼11 tonnes/ha. At scale, lignin-first biorefining of this poplar could annually generate 2.4 tonnes/ha of dissolving pulp for textiles and 1.1 m3 biofuels. Life cycle assessment indicates that, relative to cotton production, this approach could substantially reduce water consumption and identifies certain areas for further improvement. Overall, this work highlights a new value chain to reduce the environmental footprint of textiles, chemicals, and biofuels while enabling land reclamation and water savings from cotton back to food production.

Place, publisher, year, edition, pages
Elsevier, 2022
Keywords
Biofuels; Cellulose; Climate change; Cotton; Dissolution; Land reclamation; Land use; Lignin; Refining; Reforestation; Soils; Textile fibers; Textile industry; Textiles, Biorefining; Blue water; Climate-adapted poplar; Dissolving pulp; Landuse change; Life cycle assessment; Reductive catalytic fractionation; Regenerated cellulose; Saving in blue water; Short-rotation forestries, Life cycle
National Category
Other Chemical Engineering Other Environmental Engineering
Research subject
Chemical Engineering
Identifiers
urn:nbn:se:kau:diva-91713 (URN)10.1016/j.joule.2022.06.021 (DOI)000861328000012 ()2-s2.0-85135832662 (Scopus ID)
Funder
Swedish Energy Agency, 5903-1, 47448-1, and 45082-1
Available from: 2022-09-01 Created: 2022-09-01 Last updated: 2022-10-24Bibliographically approved
Ekbåge, D., Nilsson, L., Håkansson, H. & Lin, P.-I. (2020). Multiple linear regression modelling of pulp and handsheet properties based on fiber morphology measurements and process data. BioResources, 15(1), 654-676
Open this publication in new window or tab >>Multiple linear regression modelling of pulp and handsheet properties based on fiber morphology measurements and process data
2020 (English)In: BioResources, ISSN 1930-2126, E-ISSN 1930-2126, Vol. 15, no 1, p. 654-676Article in journal (Refereed) Published
Abstract [en]

A multiple regression model was evaluated to predict pulp and handsheet properties including z-directional tensile strength (z-strength) and Scott bond values. One hypothesis that was central for the model evaluation was that the crill content, as measured with ultraviolet and infrared lights, would improve the statistical models. A chemi-thermomechanical pulp (CTMP) mill designed with two parallel primary refining lines and a reject refiner was the basis for this study, and all process data and pulp samples were gathered from the specific process. Pulp was extracted from the process for an extended period from a position after the latency chest (primary refined pulp) and from the pulp-stream exiting the mill to the board machine (accept pulp). The crill content was positively correlated to the z-strength of the accept pulp, explaining 55% of the variance with a linear regression model with the drill content as the sole predictor. The estimation model of the z-strength of accept pulp was based on a combination of the crill content, freeness, fibril perimeter for longer fibers, and mean kink angle, and resulted in an R-2 of 0.79. When applying cross-validation to determine the predictive model performance, the highest R-2 obtained was 0.67. This latter model included the crill content, fibril perimeter, and mean kink angle as predictors.

Place, publisher, year, edition, pages
North Carolina State University, 2020
Keywords
CTMP, Fiber morphology, Multiple regression modelling, Handsheet, Z-strength, Scott bond, Crill
National Category
Chemical Engineering
Research subject
Chemical Engineering; Public Health Science
Identifiers
urn:nbn:se:kau:diva-77086 (URN)000511129100050 ()2-s2.0-85088375956 (Scopus ID)
Funder
Stora Enso
Available from: 2020-02-27 Created: 2020-02-27 Last updated: 2022-11-10Bibliographically approved
Ekbåge, D., Nilsson, L. & Håkansson, H. (2019). Time series analysis of refining conditions and estimated pulp properties in a chemi-thermomechanical pulp process. BioResources, 14(3), 5451-5466
Open this publication in new window or tab >>Time series analysis of refining conditions and estimated pulp properties in a chemi-thermomechanical pulp process
2019 (English)In: BioResources, ISSN 1930-2126, E-ISSN 1930-2126, Vol. 14, no 3, p. 5451-5466Article in journal (Refereed) Published
Abstract [en]

Frequently sampled process data from a conical disc refiner and infrequently sampled pulp data from a full scale chemi-thermomechanical pulp (CTMP) mill were evaluated to study autocovariance with aspects of potential dynamic modelling applicability. Two trial measurements with an online pulp analyzer at decreased sampling intervals were performed. For variability analysis, time-series containing up to one day of operational data were used. At the chip refiner, the clearest significant autocovariance was identified for the specific electricity consumption, based on the longer sequences. Most of the estimated pulp properties indicated low or non-significant autocovariance, limiting applicability of a specific dynamic model. A mill trial was conducted to investigate the impact from an increase in the conical disc gap on the specific electricity consumption and the resulting freeness. The response time from the gap change in the refiner to measured change in freeness was estimated at 19 min, which was approximately the hydraulic residence time in the latency chest. The relevance of this study lies in applicability of mill-data-driven modelling to capture the dynamics of a specific refining process. Through mill trials the sampling speed of pulp properties was more than doubled to gain insights into short term systematic variations by applying time-series-analysis.

Place, publisher, year, edition, pages
North Carolina State University, 2019
Keywords
Chemi-thermomechanical pulp (CTMP); Freeness; Dynamic modelling; conical disc refiner; Specific electricity consumption; Energy efficiency; Autocovariance
National Category
Paper, Pulp and Fiber Technology
Research subject
Environmental and Energy Systems
Identifiers
urn:nbn:se:kau:diva-65734 (URN)000473204700036 ()
Funder
Knowledge Foundation
Note

Artikeln ingick som manuskript i Ekbåges licentiatuppsats (2018) Process modelling based on data from an evaporation and a CTMP process

DOI 10.15376/biores.14.3.5451-5466

Available from: 2018-01-29 Created: 2018-01-29 Last updated: 2021-06-30Bibliographically approved
Ekbåge, D., Nilsson, L. & Håkansson, H. (2017). Trial measurements in a CTMP-process to perform time-series analysis of refining conditions and estimated pulp properties. In: : . Paper presented at 10th Fundamental Mechanical Pulp Research Seminar.
Open this publication in new window or tab >>Trial measurements in a CTMP-process to perform time-series analysis of refining conditions and estimated pulp properties
2017 (English)Conference paper, Oral presentation with published abstract (Other academic)
National Category
Paper, Pulp and Fiber Technology
Identifiers
urn:nbn:se:kau:diva-65786 (URN)
Conference
10th Fundamental Mechanical Pulp Research Seminar
Available from: 2018-01-29 Created: 2018-01-29 Last updated: 2020-05-04Bibliographically approved
Hellström, P., Heijnesson-Hulten, A., Paulsson, M., Håkansson, H. & Germgård, U. (2016). A comparative study of enzymatic and Fenton pretreatment applied to a birch kraft pulp used for MFC production in a pilot scale high-pressure homogenizer. TAPPI Journal, 15(6), 375-381
Open this publication in new window or tab >>A comparative study of enzymatic and Fenton pretreatment applied to a birch kraft pulp used for MFC production in a pilot scale high-pressure homogenizer
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2016 (English)In: TAPPI Journal, ISSN 0734-1415, Vol. 15, no 6, p. 375-381Article in journal (Refereed) Published
Abstract [en]

Microfibrillated cellulose (MFC) was produced in pilot scale from a bleached birch (Betula verrucosa) kraft pulp that was pretreated with either Fenton's reagent or with a combined mechanical and enzymatic method used at the Centre Technique du Papier (CTP; Grenoble, France). The change in fiber fibrillation during the homogenization treatment was monitored by analyzing the fiber and the fines content, size fractionation, rheological properties and visualization by light-and scanning electron microscopy (SEM). The Fenton pretreatment resulted in MFC suspensions that contained a high amount of small sized elements. After five passes through the high-pressure homogenizer, the amount of particles smaller than 20 mu m was 37% for the Fenton pretreated MFC compared to 13% for the enzymatically (endoglucanase) pretreated MFC. Altogether, the Fenton pretreatment enabled preparation of MFC with a higher degree of fibrillation after the same number of passes through the high-pressure homogenizer. Another option is to produce MFC of the same amount of fibrillation as after an enzymatic stage, but at significantly lower energy consumption.

Place, publisher, year, edition, pages
TAPPI Press, 2016
National Category
Chemical Engineering
Research subject
Chemical Engineering
Identifiers
urn:nbn:se:kau:diva-46239 (URN)000380267900004 ()
Available from: 2016-09-21 Created: 2016-09-21 Last updated: 2020-06-26Bibliographically approved
Hellström, P., Heijnesson-Hulten, A., Paulsson, M., Håkansson, H. & Germgård, U. (2014). Fenton pre-treated microfibrillated cellulose evaluated as a strength enhancer in the middle ply of paperboard. Nordic Pulp & Paper Research Journal, 29(4), 732-740
Open this publication in new window or tab >>Fenton pre-treated microfibrillated cellulose evaluated as a strength enhancer in the middle ply of paperboard
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2014 (English)In: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, E-ISSN 2000-0669, Vol. 29, no 4, p. 732-740Article in journal (Refereed) Published
Abstract [en]

Microfibrillated celluloses (MFCs), produced by various pre-treatments of a fully bleached birch kraft pulp, were evaluated as strength enhancers in test sheets representing the middle ply of paperboard. The furnish consisted of hydrogen peroxide bleached high temperature spruce chemithermomechanical pulp (HT-CTMP), MFC and a retention system containing cationic starch and an anionic silica sol. The MFC was prepared via a mechanical treatment in a colloid mill after pretreatment with Fenton's reagent, monocomponent endoglucanase or acidic hydrogen peroxide. Addition of 5% MFC, produced with Fenton pre-treatment, resulted in improved HT-CTMP properties with respect to increased tensile index (similar to 35%), z-directional strength (similar to 50%), tensile stiffness index (similar to 25%) compared to HT-CTMP test sheets prepared without MFC addition. The strength improvement was linearly correlated to the density of the tests sheet, to the surface area (BET) and to the surface charge of the enzymatic or chemically pre-treated MFCs.

Keywords
Microfibrillated cellulose, Fenton's reagent, Enzymatic hydrolysis, Tensile strength, Z-directional strength, Bending stiffness index, Bending resistance, Dewatering
National Category
Chemical Engineering
Research subject
Chemical Engineering
Identifiers
urn:nbn:se:kau:diva-41572 (URN)000346146900020 ()
Available from: 2016-04-25 Created: 2016-04-11 Last updated: 2020-06-26Bibliographically approved
Hellström, P., Heijnesson-Hulten, A., Paulsson, M., Hakansson, H. & Germgård, U. (2014). The effect of Fenton chemistry on the properties of microfibrillated cellulose. Cellulose, 21(3), 1489-1503
Open this publication in new window or tab >>The effect of Fenton chemistry on the properties of microfibrillated cellulose
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2014 (English)In: Cellulose, ISSN 0969-0239, E-ISSN 1572-882X, Vol. 21, no 3, p. 1489-1503Article in journal (Refereed) Published
Abstract [en]

A fully bleached birch kraft pulp was treated with acidic hydrogen peroxide in the presence of ferrous ions (Fenton's reagent) and thereafter treated mechanically in a colloid mill to produce a product containing microfibrillated cellulose (MFC). The produced MFC products were chemically and morphologically characterized and compared with MFC products produced without pretreatment as well as with enzymatic hydrolysis. Fenton treatment resulted in an increase in total charge and number of carbonyl groups while the intrinsic viscosity decreased. The Fenton treated pulps were easier to process mechanically i.e. they reached a higher specific surface area at a given mechanical treatment time and the MFC produced had a stable water-fibre suspension for at least 8 weeks compared to enzymatic pretreated pulps and pulps not subjected to any pretreatment.

Place, publisher, year, edition, pages
Springer, 2014
Keywords
Microfibrillated cellulose, Fenton chemistry, Enzymatic hydrolysis, Carbonyl groups, Carbohydrate composition, Total and surface charge, Suspension stability
National Category
Chemical Engineering
Research subject
Chemical Engineering
Identifiers
urn:nbn:se:kau:diva-41526 (URN)10.1007/s10570-014-0243-1 (DOI)000336322800036 ()
Available from: 2016-04-25 Created: 2016-04-11 Last updated: 2022-05-10Bibliographically approved
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