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| 2. |
- Giummarella, Nicola, et al.
(författare)
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Lignin Prepared by Ultrafiltration of Black Liquor : Investigation of Solubility, Viscosity, and Ash Content
- 2016
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Ingår i: BioResources. - : North Carolina State University. - 1930-2126. ; 11:2, s. 3494-3510
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Tidskriftsartikel (refereegranskat)abstract
- Technical lignin, which can be potentially obtained in large amounts as a by-product from kraft pulping, represents a potential resource for manufacturing fuels and chemicals. Upgrading of lignin, by lowering its molecular weight, is a valuable alternative to precipitation from black liquor, which occurs in the Lignoboost process. The solubility properties of Lignoboost lignin and filtered lignin in a number of technically feasible solvents were compared, and it was found that both lignins were dissolved in similar solvents. With the exception of furfural, the best lignin solvents generally were organic solvents miscible with water, such as methanol. It was possible to dissolve more filtered lignin in higher concentrations than Lignoboost lignin; additionally, the viscosities of the filtered lignin solutions were also considerably lower than those of Lignoboost lignin, especially at higher concentrations. Methods for non-organic component removal from filtrated lignin were tested, and it was concluded that several cold acidic treatments after dewatering can lower the ash content to values below 0.5% by weight.
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| 4. |
- Lindgren, Christofer, 1974-
(författare)
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De små medlens betydelse : Om meningsskapande, mångtydighet och styrning i offentlig förvaltning
- 2018
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Some policy work within public administrations these days seems to rely heavily on individual officials’ efforts to make sense of new policy proposals and practices to other groups in their organizations. This is the case especially with local work on cross-cutting issues such as gender and equal treatment policies, children’s rights issues, sustainability and climate policies etc. Typically, work on these matters are meant to be carried out in all parts of the public sector. However, operations in many parts of this sector are guided by managerial models giving little weight to what is usually perceived as “side issues”. Also, new policy proposals in these areas tend to be formed in complex boundary-spanning practices, involving partnerships and collaborative work, not easily compatible with administrative ideals of clear divisions of tasks and mandates. As a result, the officials responsible for work with these issues often seem to have to invest time in explaining both why certain steps ought to be implemented, and by what legitimate processes they have come about. In this study, such micro-level attempts to gain support for new policy proposals or practices in the administration through efforts to influence the meanings ascribed to them, is seen as a form of steering. The aim of the thesis is to investigate them as such, with the help of governance theory and Karl Weick’s sensemaking perspective. Thereby, the study seeks to provide insights into questions of how this micro-level steering may be analyzed, as well as issues of what they may mean for public administrations’ capacity to make sense of conflicting demands. Theoretically, the study arrives at an analytical model based on two arguments. The first is that attempts to mobilize other members of an administration in complex practices via means of influencing their understanding of these practices, could be seen a project with two thresholds. One concerns the need of explaining what type of situation or practice members are faced with, and how it fits into the order of the administration. The other concerns the need to visualize its aims in such a way that it appears desirable to groups targeted for mobilization. The second argument is that micro-level attempts to influence meaning-making processes in public administrations could be undertaken in both direct and indirect ways. They may come in the form of words and “talk” directly intended to enact certain images in the organization, but also in the form of efforts to stabilize or reinforce the social dynamics holding such images in place. The study discusses several ways in which attempts to manage this dynamic may be carried out.Empirically, the analytical model is applied to two case studies focusing on officials working in Swedish municipalities. The task set out for the cases is to investigate the officials’ attempts to gain support for an EU-funded partnership, with the objective of changing recruitment routines in their administrations. The results show that the officials indeed used both direct and indirect means to influence other members understanding of this practice. But also that there appeared to exist a certain dynamic between these means, underlining the need to apply a broad analytical framework when studying this steering, and on a more general note that such steering should be thought of as a product of both communicative and organizing skills.
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| 5. |
- Lindgren, Christofer, et al.
(författare)
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Förfarande och anordning vid kontinuerlig kokning av kemisk cellulosamassa : Method and device for the continuous cooking of pulp
- 2005
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Patent (populärvet., debatt m.m.)abstract
- The invention concerns an arrangement and a method for the continuous cooking of chemical cellulose pulp in a continuous digester system (100). The continuous digester system (100) comprises an inlet (102) for the feed of a chips suspension and an outlet (103) for the output of a cooked suspension of pulp. The suspension of chips is fed in to the inlet through a line (105) at the beginning of the cook, where the chips suspension has a volume of starting cooking fluid that establishes a fluid/wood ratio that is greater than 3.5. The invention is characterised in that a final cooking fluid is present during the cook for the major part of the cook and is withdrawn through a withdrawal strainer (106) only during the final 15 minutes of the cook. The final cooking fluid ensures a fluid/wood ratio that is greater than 3.5 in association with the withdrawal. The withdrawn final cooking fluid during the final 15 minutes of the cook consists of spent black liquor, which maintains a residual alkali level that lies under 15 g/l.
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| 7. |
- Lindström, Mikael, et al.
(författare)
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Cooking of pulp with high effective alkali concentration in the residual phase
- 1997
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Patent (populärvet., debatt m.m.)abstract
- A method and device for cooking pulp by increasing the effective alkali concentration in the residual phase of the cooking process to substantially improve the residual delignification rate and thus improving the pulp properties such as the pulp strength and pulp yield at a given lignin content.
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| 8. |
- Wedin, Helena, et al.
(författare)
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Evaluation of dyeing and finishingcomponents in recycling and regeneration ofcoloured textiles prototypes
- 2018
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- The ability to create secondary raw materials with low impurity content is importantfrom a fibre regeneration processing perspective. Cotton textiles contain colourantsand textile finish, which can be considered as impurities in a chemical recyclingprocess. Removal of such impurities in a decolourisation stage would enhance the fibredissolving capacity and stabilise and simplify the fibre regeneration process.Moreover, the removal of impurities from secondary raw materials is also importantfrom an environmental and health perspective. Chemical recycling has the potentialto deal with the risk of retaining or spreading hazardous substances further inre-circulated textile loops. Of specific concern are colourants or additives withcarcinogenic or endocrine disruptive attributes as well as bioaccumulative substancessuch as PFAS (per- and polyfluoroalkyl substances), which are commonly used intextiles for dirt and water repellency.This report describes an experimental evaluation of physical properties of decolourisedcotton regenerated into viscose fibres and an analysis of potentially hazardous textilefinish components throughout a decolourisation approach. The three main researchquestions in this report are:1. Can we obtain viscose fibres from a decolourised black cotton fabric withsimilar physical properties as commercial viscose fibres by using the re:newcelldecolourisation approach?2. Can the impact from a DMeDHEU(1) anti-wrinkle and a fatty acid softener finish onthe physical viscose fibre properties be eliminated using this decolourisation approach?3. Could chemical recycling be a potential solution for recirculation of textiles whichhave a risk of containing hazardous substances of for example PFAS dirt and waterrepellent type?The project has been performed within the Mistra Future Fashion research program byjoint work from re:newcell, MoRe research, Swerea IVF, Swedish School of Textile and RISE,and with support from the companies DyStar®, Lenzing AG, H&M, I:CO, Boob design,Wiges, New Wave Group, Filippa K and Kappahl. The part of the study that concerned thedirt and water repellent was performed in cooperation with the research project SUPFESfunded by the Swedish Research Council for Environment, Agricultural Sciences andSpatial Planning (FORMAS) under grant agreement No. 2012-2148.The study showed that viscose fibres can be produced from decolourised cotton usingthe re:newcell decolourisation approach. However, the desired physical fibre propertieswere not obtained. More optimisation in the decolourisation stage is needed to adapt thecotton substrate for the viscose process.A first indication of the softener to positively affect tenacity of the viscose fibre wasobserved. The anti-wrinkle treated fabric showed a tendency in higher reduced cloggingnumber, but no influence on the physical fibre properties was seen. While caution shouldbe taken in drawing conclusions from the few performed trials, it seems likely that theimpact from the tested types of anti-wrinkle agent and softener on the viscose processcould not be eliminated by the use of the decolourisation approach. This also raisesthe question of how persistent the softener is in a decolourisation process. The resultsfrom the analysis on dirt and water repellent substances (DWR/PFAS) throughout thedecolourisation process showed that one third remained in the pulp. This suggests thatthe DWR binds to the fibres in a way which the decolourisation process is not able toreverse.Taken together, these results are not sufficient to prove the hypothesis of whetherchemical recycling could be a potential solution for recirculation of textiles with risk forcontaining hazardous substances of this sort.The trials lead to the following conclusions: The used decolourisation approach haspotential to remove the type of reactive dye, wrinkle-free agent and softener tested inthis study. Adaption of the decolourisation process for the cotton substrate is neededin further trials. In the specific case of cotton flows with presence of dirt and waterrepellent finish we recommend designing of another decolourisation approach.
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| 9. |
- Wedin, Helena, et al.
(författare)
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Investigation of recycled viscose fibres after removal of a reactive dye combination and an easy care finish agent
- 2017
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Textile-to-textile recycling from cotton textiles can be done either mechanically or chemically. In chemical textile recycling of cotton there are challenges to overcome in order to regenerate new fibres. Two of the challenges among others are reactive dyes and wrinkle-free finishes that could disturb the regeneration process steps since these finishes are covalently linked to the cellulose.This poster discusses the impact of using a novel alkaline/acid bleaching sequence to strip reactive dyes and wrinkle-free finish (DMDHEU) from cotton textile for production of regenerated viscose fibre properties. The results might generate a promising step forward to overcome quality challenges for cellulosic chemical recycling.
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| 10. |
- Wedin, Helena, et al.
(författare)
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Preparation of Viscose Fibres Stripped of Reactive Dyes and Wrinkle-Free Crosslinked Cotton Textile Finish
- 2018
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Ingår i: Journal of Polymers and the Environment. - : Springer Science and Business Media LLC. - 1566-2543 .- 1572-8919. ; 26:9, s. 3603-3612
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Tidskriftsartikel (refereegranskat)abstract
- The chemical recycling of cellulosic fibres may represent a next-generation fibre–fibre recycling system for cotton textiles, though remaining challenges include how to accommodate fibre blends, dyes, wrinkle-free finishes, and other impurities from finishing. These challenges may disrupt the regeneration process steps and reduce the fibre quality. This study examines the impact on regenerated viscose fibre properties of a novel alkaline/acid bleaching sequence to strip reactive dyes and dimethyloldihydroxyethyleneureas (DMDHEU) wrinkle-free finish from cotton textiles. Potentially, such a bleaching sequence could advantageously be integrated into the viscose process, reducing the costs and environmental impact of the product. The study investigates the spinning performance and mechanical properties (e.g., tenacity and elongation) of the regenerated viscose fibres. The alkaline/acid bleaching sequence was found to strip the reactive dye and DMDHEU wrinkle-free finish from the cotton fabric, so the resulting pulp could successfully be spun into viscose fibres, though the mechanical properties of these fibres were worse than those of commercial viscose fibres. This study finds that reactive dyes and DMDHEU wrinkle-free finish affect the viscose dope quality and the regeneration performance. The results might lead to progress in overcoming quality challenges in cellulosic chemical recycling.
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