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Engstrand, Per, ProfessorORCID iD iconorcid.org/0000-0003-1881-6473
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Publications (10 of 148) Show all publications
Rahman, H., Eyob, F. K., Norlin, B. & Engstrand, P. (2023). Improved CTMP impregnation by the use of X-ray fluorescence measurements. In: : . Paper presented at Treesearch Insight Conference, Lund University and MAXIV,24-25 May 2023, Lund, Sweden..
Open this publication in new window or tab >>Improved CTMP impregnation by the use of X-ray fluorescence measurements
2023 (English)Conference paper, Poster (with or without abstract) (Other academic)
Abstract [en]

Defibration of wood chips in high-yield pulping such as CTMP production involves sulfonation of wood chips using (Na2SO3). When aiming to improve product properties, one key issue to investigate is the evenness of the sulfonation, i.e., the distribution of the sulfite (SO32-) ions. The challenge is that the inner parts of the wood chips absorb much less sodium sulfite than the outer parts. As a result, less sulfonated wood fibers have different bonding properties. It is likely that the efficiency and evenness of fiber separation in a chip refiner depend greatly on how evenly the chips have been sulfonated. Uneven sulfonation then results in higher shives (unseparated fibers) content which impairs product properties. We suggest a laboratory-scale miniaturized X-ray fluorescence (XRF) scanner for measuring sulfur distribution in the wood chips on-site. By minimizing the differences in sulphonate content between fibers, we can minimize the requirement for sulfite (SO32-) dosage to a certain degree of fiber separation, thereby reducing the total amount of electricity used in chip refining. There has been a significant improvement in commercial XRF microscopy scanners over the last few years, but the spatial resolutions achieved are insufficient. We have developed an XRF scanner optimized for sulfur fluorescence energies [1], and further continued this development by implementing frontier technology polycapillary X-ray optics. We present spatial resolution measurements and discuss the relevance and usability of the proposed measurement methodology to demonstrate its performance.

[1] Rahman, H., et.al, ACS Omega 2022, 7, 51, 48555–48563, DOI: 10.1021/acsomega.2c07086

Keywords
XRF, Sulfonation
National Category
Chemical Engineering Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:miun:diva-48393 (URN)
Conference
Treesearch Insight Conference, Lund University and MAXIV,24-25 May 2023, Lund, Sweden.
Available from: 2023-05-31 Created: 2023-05-31 Last updated: 2024-03-05Bibliographically approved
Mattsson, A., Joelsson, T., Pettersson, G., Ketoja, J., Mietinen, A. & Engstrand, P. (2023). Lignin Inter-Diffusion Underlying Improved Mechanical Performance of Hot-Pressed Paper Webs. In: Domenico Acierno and Antonella Patti (Ed.), Mechanical Performance of Sustainable Bio-Based Compounds: (pp. 213-228). Basel: MDPI
Open this publication in new window or tab >>Lignin Inter-Diffusion Underlying Improved Mechanical Performance of Hot-Pressed Paper Webs
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2023 (English)In: Mechanical Performance of Sustainable Bio-Based Compounds / [ed] Domenico Acierno and Antonella Patti, Basel: MDPI, 2023, p. 213-228Chapter in book (Refereed)
Abstract [en]

Broader use of bio-based fibres in packaging becomes possible when the mechanical properties of fibre materials exceed those of conventional paperboard. Hot-pressing provides an efficient method to improve both the wet and dry strength of lignin-containing paper webs. Here we study varied pressing conditions for webs formed with thermomechanical pulp (TMP). The results are compared against similar data for a wide range of other fibre types. In addition to standard strength and structural measurements, we characterise the induced structural changes with X-ray microtomography and scanning electron microscopy. The wet strength generally increases monotonously up to a very high pressing temperature of 270 ◦C. The stronger bonding of wet fibres can be explained by the inter-diffusion of lignin macromolecules with an activation energy around 26 kJ mol−1 after lignin softening. The associated exponential acceleration of diffusion with temperature dominates over other factors such as process dynamics or final material density in setting wet strength. The optimum pressing temperature for dry strength is generally lower, around 200 ◦C, beyond which hemicellulose degradation begins. By varying the solids content prior to hot-pressing for the TMP sheets, the highest wet strength is achieved for the completely dry web, while no strong correlation was observed for the dry strength.

Place, publisher, year, edition, pages
Basel: MDPI, 2023
Keywords
hot-pressing, paper web, fibre, lignin, diffusion, activation energy
National Category
Paper, Pulp and Fiber Technology
Identifiers
urn:nbn:se:miun:diva-47780 (URN)10.3390/books978-3-0365-6684-9 (DOI)978-3-0365-6685-6 (ISBN)978-3-0365-6684-9 (ISBN)
Projects
NeoPulpFORIC+
Note

This book is a reprint of the Special Issue Mechanical Performance of Sustainable Bio-Based Compounds that was published in Polymers 2021.

Available from: 2023-03-13 Created: 2023-03-13 Last updated: 2023-10-20Bibliographically approved
Negro, C., Pettersson, G., Mattsson, A., Nyström, S., Sanchez-Salvador, J. L., Blanco, A. & Engstrand, P. (2023). Synergies between Fibrillated Nanocellulose and Hot-Pressing of Papers Obtained from High-Yield Pulp. Nanomaterials, 13(13), Article ID 1931.
Open this publication in new window or tab >>Synergies between Fibrillated Nanocellulose and Hot-Pressing of Papers Obtained from High-Yield Pulp
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2023 (English)In: Nanomaterials, E-ISSN 2079-4991, Vol. 13, no 13, article id 1931Article in journal (Refereed) Published
Abstract [en]

To extend the application of cost-effective high-yield pulps in packaging, strength and barrier properties are improved by advanced-strength additives or by hot-pressing. The aim of this study is to assess the synergic effects between the two approaches by using nanocellulose as a bulk additive, and by hot-pressing technology. Due to the synergic effect, dry strength increases by 118% while individual improvements are 31% by nanocellulose and 92% by hot-pressing. This effect is higher for mechanical fibrillated cellulose. After hot-pressing, all papers retain more than 22% of their dry strength. Hot-pressing greatly increases the paper’s ability to withstand compressive forces applied in short periods of time by 84%, with a further 30% increase due to the synergic effect of the fibrillated nanocellulose. Hot-pressing and the fibrillated cellulose greatly decrease air permeability (80% and 68%, respectively) for refining pretreated samples, due to the increased fiber flexibility, which increase up to 90% using the combined effect. The tear index increases with the addition of nanocellulose, but this effect is lost after hot-pressing. In general, fibrillation degree has a small effect which means that low- cost nanocellulose could be used in hot-pressed papers, providing products with a good strength and barrier capacity. 

Place, publisher, year, edition, pages
MDPI, 2023
Keywords
cellulose nanofibers, CTMP, high-yield pulp, hot-pressing technology, microcellulose, nanocellulose, packaging, paper quality
National Category
Paper, Pulp and Fiber Technology
Identifiers
urn:nbn:se:miun:diva-49037 (URN)10.3390/nano13131931 (DOI)001028321900001 ()2-s2.0-85164693722 (Scopus ID)
Available from: 2023-08-15 Created: 2023-08-15 Last updated: 2023-08-16Bibliographically approved
Norlin, B., An, S., Granfeldt, T., Krapohl, D., Lai, B., Rahman, H., . . . Engstrand, P. (2023). Visualisation of sulphur on single fibre level for pulping industry. Paper presented at 23rd International Workshop on Radiation Imaging Detectors 26–30 June 2022. Journal of Instrumentation, 18(01), C01012-C01012
Open this publication in new window or tab >>Visualisation of sulphur on single fibre level for pulping industry
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2023 (English)In: Journal of Instrumentation, ISSN 1748-0221, E-ISSN 1748-0221, Vol. 18, no 01, p. C01012-C01012Article in journal (Refereed) Published
Abstract [en]

In the pulp and paper industry, about 5 Mt/y chemithermomechanical pulp (CTMP) are produced globally from softwood chips for production of carton board grades. For tailor making CTMP for this purpose, wood chips are impregnated with aqueous sodium sulphite for sulphonation of the wood lignin. When lignin is sulphonated, the defibration of wood into pulp becomes more selective, resulting in enhanced pulp properties. On a microscopic fibre scale, however, one could strongly assume that the sulphonation of the wood structure is very uneven due to its macroscale size of wood chips. If this is the case and the sulphonation could be done significantly more evenly, the CTMP process could be more efficient and produce pulp even better suited for carton boards. Therefore, the present study aimed to develop a technique based on X-ray fluorescence microscopy imaging (µXRF) for quantifying the sulphur distribution on CTMP wood fibres. Firstly, the feasibility of µXRF imaging for sulphur homogeneity measurements in wood fibres needs investigation. Therefore, clarification of which spatial and spectral resolution that allows visualization of sulphur impregnation into single wood fibres is needed. Measurements of single fibre imaging were carried out at the Argonne National Laboratory’s Advanced Photon Source (APS) synchrotron facility. With a synchrotron beam using one micrometre scanning step, images of elemental mapping are acquired from CTMP samples diluted with non-sulphonated pulp under specified conditions. Since the measurements show significant differences between sulphonated and non-sulphonated fibres, and a significant peak concentration in the shell of the sulphonated fibres, the proposed technique is found to be feasible. The required spatial resolution of the µXRF imaging for an on-site CTMP sulphur homogeneity measurement setup is about 15 µm, and the homogeneity measured along the fibre shells is suggested to be used as the CTMP sulphonation measurement parameter.

Place, publisher, year, edition, pages
Institute of Physics (IOP), 2023
Keywords
X-ray fluorescence (XRF) systems, Instruments for environmental monitoring, food control and medical use, Data processing methods, Image filtering
National Category
Engineering and Technology Paper, Pulp and Fiber Technology Other Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:miun:diva-46798 (URN)10.1088/1748-0221/18/01/c01012 (DOI)000926596900007 ()2-s2.0-85146430079 (Scopus ID)
Conference
23rd International Workshop on Radiation Imaging Detectors 26–30 June 2022
Projects
Micro X-ray Project
Funder
Vinnova, 2020-03791
Available from: 2023-01-11 Created: 2023-01-11 Last updated: 2024-01-10Bibliographically approved
Rahman, H., An, S., Norlin, B., Persson, E., Engstrand, P. & Granfeldt, T. (2022). Characterization of impregnation depth in wood fibers related manufacturing of advanced fiber materials replacing fossil-based materials. In: Proceedings International mechanical Pulping Conference: . Paper presented at 32nd International Mechanical Pulping Conference (IMPC), Vancouver, Canada, June 5-8, 2022 (pp. 162-165).
Open this publication in new window or tab >>Characterization of impregnation depth in wood fibers related manufacturing of advanced fiber materials replacing fossil-based materials
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2022 (English)In: Proceedings International mechanical Pulping Conference, 2022, p. 162-165Conference paper, Poster (with or without abstract) (Other academic)
Abstract [en]

An underestimated problem in the rapidly growing CTMP industry is uneven sulphonation. Optimizing the unit operations before chip refining, chip washing, steaming, impregnation, and preheating improves efficiency, provides smoother fiber properties, and reduces the cost of certain properties in the final product. Impregnation is crucial to the CTMP quality, and a further improvement in its smoothness requires a careful study of the optimization of pulpwood chipping and the chipping process with reduction technology at sawmills. The CTMP system, however, is difficult to optimize due to the lack of rapid measurement methods for determining the smoothness of the impregnation at the fiber level. The ability to study how the processing system can be optimized requires a robust method of measuring the degree of sulphonation at the fiber level. It is possible to study CTMP's degree of sulphonation at the fiber level by measuring the distribution of elemental sulphur and counterions of the sulphonate groups, such as sodium or calcium. Thus, we are developing an XRF (x-ray fluorescence) technology based on scanning imaging and energy-resolved X-ray spectrum from a collimated X-ray source. The measurement technology is developed so that it can be used in pulp industry laboratories.

Keywords
CTMP, Impregnation, Single fiber, Sulphona-tion and X-ray fluorescence
National Category
Engineering and Technology Chemical Engineering
Identifiers
urn:nbn:se:miun:diva-46226 (URN)
Conference
32nd International Mechanical Pulping Conference (IMPC), Vancouver, Canada, June 5-8, 2022
Projects
Micro X-ray Project
Available from: 2022-10-06 Created: 2022-10-06 Last updated: 2023-02-27Bibliographically approved
Sund, J., Sandberg, C., Thungström, G. & Engstrand, P. (2022). Continuous online fibre analysis enables improved pulp quality estimation and control. In: Proceedings of the International Mechanical Pulping Conference: . Paper presented at IMPC 2022, Vancouver, BC, Canada, June 5-8, 2022 (pp. 99-106).
Open this publication in new window or tab >>Continuous online fibre analysis enables improved pulp quality estimation and control
2022 (English)In: Proceedings of the International Mechanical Pulping Conference, 2022, p. 99-106Conference paper, Published paper (Other academic)
Abstract [en]

In this work, high-rate fibre analysis has been used for direct feedback control of pulp quality by application of a new control strategy for a two-stage refining process in the Holmen Hallsta mill, Sweden. The application is based on control of pulp freeness, estimated from the continuous fibre analysis results from a BTG Single Point Morphology ana-lyzer. The goal was to create a robust and simple control strategy. The new strategy includes control of plate gap, con-sistency and the hydraulic force difference between the stages. Expressed as standard deviation, the freeness and av-erage fibre length variations were reduced by 50% and 25% respectively. The small size of the pulp chest in this process also benefits stronger feedback control. Long-term operation suggest that high-rate fibre analysis can be used to reduce faster quality variation.

Keywords
Mechanical pulping, Refiner, Control, Online fibre analyser, Pulp quality
National Category
Wood Science
Identifiers
urn:nbn:se:miun:diva-47686 (URN)
Conference
IMPC 2022, Vancouver, BC, Canada, June 5-8, 2022
Available from: 2023-02-27 Created: 2023-02-27 Last updated: 2023-02-27Bibliographically approved
Rahman, H., Engstrand, P., Persson, E., An, S., Norlin, B., Zeeshan, F. & Granfeldt, T. (2022). Development of improved CTMP with even sulphonate distribution at fibre level using XRF analysis. In: Douglas W. Coffin and Warren J. Batchelor (Ed.), Transactions of the 17th Fundamental Research Symposium held in Cambridge: August/September 2022: Volume 1. Paper presented at 17th Fundamental Research Symposium (Advance in pulp and paper Research) FRS, Cambridge, UK, Aug/Sep 2022 (pp. 3-11). , 1, Article ID Fibres.
Open this publication in new window or tab >>Development of improved CTMP with even sulphonate distribution at fibre level using XRF analysis
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2022 (English)In: Transactions of the 17th Fundamental Research Symposium held in Cambridge: August/September 2022: Volume 1 / [ed] Douglas W. Coffin and Warren J. Batchelor, 2022, Vol. 1, p. 3-11, article id FibresConference paper, Published paper (Refereed) [Artistic work]
Abstract [en]

Optimizing the fiber property distribution could increase the pulp properties as well as the process efficiency of chemimechanical pulps (CMP/CTMP). This can only be achieved with a better understanding of how evenly distributed sulphonate concentrations are between the individual CTMP fibres. Given that the quality of wood chips varies with the chipping methods used in pulpwood processing and sawmill processing, as well as with the chip screening system, it is a challenge to develop an impregnation process that ensures even distribution of sodium sulphite (Na2SO3) in the liquid used to impregnate the chemimechanical pulp (CMP/CTMP). Therefore, the distribution of sulphonate groups within wood chips and individual fibers must be measured at the microscale level. On a micro level, the degree of unevenness, ie, the amount of fiber sulphonation and softening before defibration, cannot be determined due to the use of excessively robust or complex processing methods. By having it, we could better understand how sulphonation occurs before defibration, so we could improve impregnation. Developing a laboratory-scale miniaturized energy dispersive X-ray fluorescence (ED-XRF) method that measures sulfur distribution at the fiber level can enable us to study the influence of impregnation on improving processes.

National Category
Chemical Engineering
Identifiers
urn:nbn:se:miun:diva-46399 (URN)978-0-9926163-6-6 (ISBN)
Conference
17th Fundamental Research Symposium (Advance in pulp and paper Research) FRS, Cambridge, UK, Aug/Sep 2022
Projects
Micro X-ray project
Note

There will be a second volume published based on all questions addressed during the presentation by the main author at the Conference

Available from: 2022-11-04 Created: 2022-11-04 Last updated: 2023-06-08Bibliographically approved
Rahman, H., Engstrand, P., Persson, E., Siwen, A., Norlin, B., Zeeshan, F. & Granfeldt, T. (2022). Development of improved CTMP with even sulphonate distribution at fibre level using XRF analysis: Discussion contributions. In: Douglas W. Coffin and Warren J. Batchelor (Ed.), Transactions of the 17th Fundamental Research Symposium held in Cambridge: August/September 2022: Volume 2. Paper presented at 17th Fundamental Research Symposium (Advance in pulp and paper Research) FRS, Cambridge, UK, Aug/Sep 2022 (pp. 579-584). Oxfordshire: The Pulp and paper Fundamental Research Society, 2
Open this publication in new window or tab >>Development of improved CTMP with even sulphonate distribution at fibre level using XRF analysis: Discussion contributions
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2022 (English)In: Transactions of the 17th Fundamental Research Symposium held in Cambridge: August/September 2022: Volume 2 / [ed] Douglas W. Coffin and Warren J. Batchelor, Oxfordshire: The Pulp and paper Fundamental Research Society , 2022, Vol. 2, p. 17p. 579-584Conference paper, Published paper (Refereed)
Place, publisher, year, edition, pages
Oxfordshire: The Pulp and paper Fundamental Research Society, 2022. p. 17
Keywords
CTMP, Impregnation, Sulphonation, Synchrotron and XRF
National Category
Engineering and Technology Chemical Engineering Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:miun:diva-48412 (URN)978-0-9926163-7-3 (ISBN)
Conference
17th Fundamental Research Symposium (Advance in pulp and paper Research) FRS, Cambridge, UK, Aug/Sep 2022
Note

This second volume is based on all questions addressed during the presentations.

Available from: 2023-06-02 Created: 2023-06-02 Last updated: 2023-09-07Bibliographically approved
Hedlund, A., Björkqvist, O., Nilsson, A. & Engstrand, P. (2022). Energy Optimization in a Paper Mill Enabled by a Three-Site Energy Cooperation. Energies, 15(8), Article ID 2715.
Open this publication in new window or tab >>Energy Optimization in a Paper Mill Enabled by a Three-Site Energy Cooperation
2022 (English)In: Energies, E-ISSN 1996-1073, Vol. 15, no 8, article id 2715Article in journal (Refereed) Published
Abstract [en]

Although there are opportunities to reduce electrical energy demand in unit processes of mechanical pulp-based paper and paperboard production, this may not be financially beneficial. This is generally because energy optimization opportunities connected to reduced refiner electricity demand in mechanical pulping systems also results in less steam available for the drying of the paper. As modern high consistency refiner systems produce approximately one ton of steam for each MWh of electricity when producing one ton of pulp, a reduction in electric energy demand leads to increased fuel demand in steam boilers to compensate for the steam shortage. In this study, we investigated what the financial and environmental situation would look like if we were to expand the system border from a paper mill to a larger system consisting of a mechanical pulp-based paper or paperboard mill, a district heating system with an incineration boiler and a chemical pulp mill. Mechanical pulp production has a wood to product yield of >90%, a high electric energy demand to separate woodchips to pulp and is a net producer of heat and steam while chemical pulp-based production has a wood to product yield of 50%, a low electric energy demand and is a net heat and electricity producer due to the combustion of dissolved wood polymers. The aim of this research is to create useful and robust models of how to use excess heat from certain industry sites to cover the steam shortage in other industry sites by means of utilizing and optimizing the district heating systems connecting these sites. For this purpose, we used a simulation tool which dynamically allows us to evaluate different scenarios. Our results shows that there is great potential to reduce both carbon dioxide emissions and production costs for industry sites and society by means of these tools.

Keywords
energy optimization, cooperation, energy reduction, collaboration between actors, district heating, industrial symbiosis
National Category
Energy Systems
Identifiers
urn:nbn:se:miun:diva-44954 (URN)10.3390/en15082715 (DOI)000786192800001 ()2-s2.0-85131566102 (Scopus ID)
Available from: 2022-05-05 Created: 2022-05-05 Last updated: 2023-08-28Bibliographically approved
Joelsson, T., Sandberg, C., Norgren, S., Alamin, I. & Engstrand, P. (2022). Fibre morphology affects the bonding and densification of hot-pressed thermomechanical pulp-based paper. In: Proceedings of the International Mechanical Pulping Conference: . Paper presented at IMPC 2022, Vancouver, BC, Canada, June 5-8, 2022 (pp. 142-148).
Open this publication in new window or tab >>Fibre morphology affects the bonding and densification of hot-pressed thermomechanical pulp-based paper
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2022 (English)In: Proceedings of the International Mechanical Pulping Conference, 2022, p. 142-148Conference paper, Published paper (Other academic)
Abstract [en]

A successful way to increase the strength properties for pulps based on lignin-rich fibres is to compress the fibre structure at high temperature by means of hot-pressing technology. The fundamental knowledge of how the fi-bre morphology influences the mechanical properties when a paper sheet is hot-pressed is still scarce. Paper sheets based on thermomechanical pulp (TMP) produced with single disc and double disc refiners were compared. The effect of degree of refining was studied as well as the effect of fibre shapes by fractionating pulp with hydrocyclones. Additionally, the effect of fines was studied. All pulps were produced at the Holmen Bra-viken Mill, Norrköping, Sweden with Norway Spruce (Picea abies) as raw material. Handsheets (100 g/m2) with 62% ± 3 dryness were hot-pressed at temperatures up to 260°C at a pressure around 8MPa. The hot-press-ing increased both dry and wet strength for all pulps studied. This was true even for pulps with low fines con-tent and low refining energy. Even thick-walled fibres normally giving lower strength showed an increase of 100% when hot-pressed. In summary, hot-pressing technology can make it possible to use different TMPs to produce strong packaging materials for use in dry and wet conditions.

Keywords
hot-pressing, fibre morphology, TMP, strength, wet stability
National Category
Wood Science
Identifiers
urn:nbn:se:miun:diva-47688 (URN)
Conference
IMPC 2022, Vancouver, BC, Canada, June 5-8, 2022
Available from: 2023-02-27 Created: 2023-02-27 Last updated: 2023-10-20Bibliographically approved
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ORCID iD: ORCID iD iconorcid.org/0000-0003-1881-6473

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