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Use of a Voith flotation cell for removal of lipophilic extractives and Mn ions from spruce thermomechanical pulping process waters
Mid Sweden University, Faculty of Science, Technology and Media, Department of applied science and design.ORCID iD: 0000-0002-0770-2086
Mid Sweden University, Faculty of Science, Technology and Media, Department of applied science and design.ORCID iD: 0000-0002-5543-2041
Mid Sweden University, Faculty of Science, Technology and Media, Department of applied science and design.
Mid Sweden University, Faculty of Science, Technology and Media, Department of applied science and design.ORCID iD: 0000-0003-3407-7973
2012 (English)In: BioResources, ISSN 1930-2126, E-ISSN 1930-2126, Vol. 7, no 3, 2784-2126 p.Article in journal (Refereed) Published
Abstract [en]

The effects of a chelating surfactant and different foaming agents on the efficiency of cleaning process waters from a thermomechanical pulp (TMP) mill were studied in a Voith flotation cell. Turbidity measurements and gas chromatography were used to determine the removal extent and characteristics of dissolved and colloidal substances (DisCo). The metal ion content in the process waters before flotation and the metal chelate removal after flotation were determined using inductively coupled plasma-optical emission spectrometry (ICP-OES). FiberLab (TM) equipment was used to characterize changes in the size of fibers present in the process waters. The results indicate that a decrease in turbidity of up to 91% and the removal of 80% of lipophilic extractives in the TMP water could be obtained using a single-stage flotation unit. Furthermore, the foam fraction was within 5% of the initial volume, and 100% of the Mn2+/chelating surfactant complex added to the TMP water was removed.

Place, publisher, year, edition, pages
2012. Vol. 7, no 3, 2784-2126 p.
Keyword [en]
Flotation; Extractives; Foaming agents; Chelating surfactant; Purification; Internal cleaning stage
National Category
Chemical Engineering
Identifiers
URN: urn:nbn:se:miun:diva-16095ISI: 000307639900007ScopusID: 2-s2.0-84865758132OAI: oai:DiVA.org:miun-16095DiVA: diva2:516203
Projects
FORE/Återvinn
Available from: 2012-04-17 Created: 2012-04-17 Last updated: 2016-10-27Bibliographically approved
In thesis
1. REMOVAL OF LIPOPHILIC EXTRACTIVES AND MANGANESE IONS FROM SPRUCE TMP WATER BY FLOTATION
Open this publication in new window or tab >>REMOVAL OF LIPOPHILIC EXTRACTIVES AND MANGANESE IONS FROM SPRUCE TMP WATER BY FLOTATION
2012 (English)Licentiate thesis, comprehensive summary (Other academic)
Abstract [en]

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.

iii

The 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.

Place, publisher, year, edition, pages
Sundsvall: Mittuniversitet, 2012. 50 p.
Series
Mid Sweden University licentiate thesis, ISSN 1652-8948 ; 74
Keyword
Flotation, Foaming agents, Chelating surfactant, TMP process water, Pitch control, Internal cleaning stage
National Category
Physical Chemistry
Identifiers
urn:nbn:se:miun:diva-16088 (URN)978-91-87103-01-8 (ISBN)
Presentation
2012-03-01, sal O102, Mid Sweden University, Sundsvall, 10:15 (English)
Opponent
Supervisors
Projects
ReGain/FORE
Available from: 2012-04-17 Created: 2012-04-17 Last updated: 2014-06-27Bibliographically approved
2. Selective Separation Of Wood Components In Internal Process Waters Originating From Mechanical Pulping
Open this publication in new window or tab >>Selective Separation Of Wood Components In Internal Process Waters Originating From Mechanical Pulping
2014 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

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 investigations

presented 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.

Place, publisher, year, edition, pages
Sundsvall: Mid Sweden University, 2014. 178 p.
Series
Mid Sweden University doctoral thesis, ISSN 1652-893X ; 184
Keyword
flotation, foaming agents, chelating surfactant, TMP process water, pitch control, internal cleaning stage, hemicellulose recovery, anti‐solvents, solvents, precipitation
National Category
Polymer Chemistry
Identifiers
urn:nbn:se:miun:diva-22244 (URN)978-91-87557-45-3 (ISBN)
Public defence
2014-05-28, O102, Holmgatan 10, Sundsvall, 12:33 (English)
Opponent
Supervisors
Projects
FORE
Funder
Knowledge Foundation, 2180
Available from: 2014-06-27 Created: 2014-06-23 Last updated: 2015-03-13Bibliographically approved

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Zasadowski, DariuszHedenström, ErikEdlund, HåkanNorgren, Magnus
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