| 1. |
- Strand, Anders, et al.
(författare)
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Selective froth flotation of pitch components from spruce TMP process water
- 2012
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Ingår i: Appita journal. - 1038-6807. ; 65:4, s. 337-346
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Tidskriftsartikel (refereegranskat)abstract
- Selective removal of dissolved and colloidal pitch components from an unbleached thermomechanical pulp (TMP)pressate by addition of a cationic foaming agent, dodecyltrimethylammonium chloride (DoTAC), and subsequent frothflotation was assessed. The experiments were conducted with varying pH, temperature, and concentrations of DoTACand calcium. The concentrations of pitch components, lignans, and dissolved polysaccharides were determinedbefore and after flotation.All pitch components were removed more efficiently by flotation at pH 5 and 3.5 than by flotation at pH 7.6. Resinand fatty acids were removed to a higher degree than neutral pitch substances at all the tested pH levels. Most of thewater-soluble uronic acids and galactoglucomannans stayed in the TMP water after flotation.Froth flotation with DoTAC was an effective way of selectively removing colloidal and dissolved pitch. Removal of pitch,especially of resin acids, at an early stage should be beneficial to the overall papermaking process.
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| 2. |
- Yang, Jiayi, et al.
(författare)
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Biorefining of Spruce TMP Process Water : Selective Fractionation of Lipophilic Extractives with Induced Air Flotation and Surface Active Additive
- 2019
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Ingår i: BioResources. - : BioResources. - 1930-2126. ; 14:2, s. 4124-4135
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Tidskriftsartikel (refereegranskat)abstract
- Lignocellulose biomass plays an important role in reducing thedependency on fossil fuels and ameliorating the dire consequences ofclimate change. It is therefore important that all the components oflignocellulose biomass are exploited. These components includehemicelluloses and extractives that are liberated and sterically stabilizedduring the thermomechanical pulping and that form the dissolved andcolloidal substance (DCS) in the process water. Biorefining of this processwater can extract these substances, which have a number of promisingapplications and can contribute to the full exploitation of lignocellulosebiomass. This paper presents a simple treatment of unbleached Norwayspruce (Picea abies) process water from TMP (thermomechanical pulping)production using induced air flotation (IAF) and cationic surfactant,dodecyl trimethylammonium chloride (DoTAC) to refine the extractivesand prepare the waters so that hemicellulose could be easily harvested ata later stage. By applying 80 ppm of DoTAC at a pH of 3.5 and 50 °Cbefore induced air flotation, 94% of the lipophilic extractives wererecovered from process water. Dissolved hemicellulose polysaccharideswere cleansed and left in the treated process water. The process enabledefficient biorefining of lipophilic extractives and purification of the processwater to enable more selective harvesting of hemicelluloses in subsequentsteps.
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| 3. |
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| 4. |
- Zasadowski, Dariusz, 1980-
(författare)
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REMOVAL OF LIPOPHILIC EXTRACTIVES AND MANGANESE IONS FROM SPRUCE TMP WATER BY FLOTATION
- 2012
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Dissolved and Colloidal substances (DisCo) and metals are released from wood during thermomechanical pulp (TMP) production. The mechanical treatment causes that these components have a tendency to accumulate in process waters, as the water circulation systems in integrated paper mills are being closed. Disturbances such as pitch depositions on the paper machine (pitch problems), specks in the paper, decreased wet and dry strength, interference with cationic process chemicals, and impaired sheet brightness and friction properties appear in the presence of DisCo substances. The presence of transition metal ions such as manganese results in higher consumption of bleaching chemicals (hydrogen peroxide) and lowers the optical quality of the final product, and addition of complexing agents, such as EDTA or DTPA, to prevent this is needed. The never ending trends to decrease water consumption and increase process efficiency in pulp and paper production stress that it is very important both to know the effects of wood substances on pulping and papermaking and to be able to remove them in an efficient way.Carried out investigations presented in this thesis show that the lipophilic extractives can be removed from TMP press water to high extent. A 90% decrease in turbidity and a 91% removal of lipophilic extractives from TMP press water can be obtained by addition of a cationic surfactant as foaming agent during flotation. Additionally, fibres located in TMP press water are not removed with the foam fraction but purified. A retained concentration of hydrophilic extractives in the process water indicates that the flotation is selective. Moreover, by introduction of a new recoverable surface active complexing agent, a chelating surfactant, manganese ions in the form of chelates can be successfully removed from the pulp fibres and separated from the process water in the same flotation process.iiiThe findings presented above indicate new possibilities for internal water cleaning and decreased emissions to water if flotation technology is applied in an integrated mechanical pulp mill.
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| 5. |
- Zasadowski, Dariusz, 1980-
(författare)
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Selective Separation Of Wood Components In Internal Process Waters Originating From Mechanical Pulping
- 2014
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Dissolved and Colloidal substances (DSC) and metals are released from woodduring thermomechanical pulp (TMP) production. These components have atendency to accumulate in process waters, as the water circulation systems inintegrated paper mills are closed. Disturbances such as pitch depositions in thepaper machine (pitch problems), specks in the paper, decreased wet and drystrength, interference with cationic process chemicals, and impaired sheetbrightness and friction properties appear when DSC are present. Transition metalions such as manganese results in higher consumption of bleaching chemicals(hydrogen peroxide) and lowers the optical quality of the final product, andaddition of complexing agents, such as EDTA or DTPA, to prevent this is needed.The never ending trends to decrease water consumption and increase processefficiency in pulp and paper production emphasizes that it is very important bothto know the effects of wood substances on pulping and papermaking and to beable to remove them in an efficient way. From a biorefinery point of view, DSCcomponents can be promising renewable raw materials for biofuels, bio‐basedchemicals and materials.In this thesis, a new approach using induced air flotation (IAF) without a cationicpolyelectrolyte addition for the removal of pitch and metal ions from mechanicalpulp mill process waters is presented. The induced air flotation of different processwaters is facilitated by the addition of a chelating surfactant and different foamingagents. The influence of the pH value, temperature and foaming agentconcentration on the flotation efficiency has been investigated. The investigationspresented show that the disturbing components can be removed from TMP presswater to a high extent. A 90% decrease in turbidity and a 91% removal of lipophilicextractives (i.e. resin and fatty acids, triglycerides, sterols and steryl esters) fromunbleached and bleached TMP process water can be obtained by addition of acationic surfactant as foaming agent during flotation. Lower amount of foamingagent is needed to purify efficiently bleached TMP process water, than unbleached.Additionally, fibres located in TMP press water are not removed with the foamfraction but purified. A retained concentration of hydrophilic extractives (i.e.hemicelluloses and lignans) in the process water indicates that the flotation isselective. Moreover, by introduction of a new recoverable surface activecomplexing agent, a chelating surfactant, manganese ions in the form of chelatescan be successfully removed from the pulp fibres and separated from the processwater in the same flotation process. Furthermore, from the purified unbleachedTMP process water a 90% recovery of dissolved hemicelluloses by anti‐solventprecipitation was obtained.The findings presented above indicate new possibilities for the internal watercleaning stage to decrease DSC emissions to recipient and for recovery of valuableraw materials from purified process water if flotation technology is applied in anintegrated mechanical pulp mill.
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