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Author:Trogen, Mikaela
Title:Autohydrolysis of softwood prior to alkaline pulping
Publication type:Master's thesis
Publication year:2010
Pages:67 s. + liitt. 4      Language:   eng
Department/School:Puunjalostustekniikan laitos
Main subject:Selluloosatekniikka   (Puu-23)
Supervisor:Sixta, Herbert
Instructor:
OEVS:
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Location:P1 Ark Aalto  2300   | Archive
Keywords:autohydrolysis
softwood
alkaline pulping
autohydrolyysi
havupuu
alkalinen keitto
autohydrolys
barrved
alkalisk massaframställning
Abstract (eng): This work focused on auto hydrolysis followed by alkaline pulping of softwood.
As raw material pine (pinus sylvestris) and spruce (picea abies) were used.
The influence of different hydrolysis and cooking conditions was investigated.

The objectives of the thesis were:.

1.
To find the optimal hydrolysis conditions in order to extract as much hemicelluloses as possible, while avoiding unfavourable side reactions (for instance lignin condensation reactions).

2.
To find the optimal cooking conditions for the pre-hydrolysed wood chips in order to maintain good pulp yield and properties.

3.
To investigate the influence of anthraquinone on the pulping of pre-hydrolysed wood chips.

4.
Lower the sulphidity level in the cooking process.

The results showed that pre-hydrolysed pulps reached lower kappa numbers at the same H-factor compared to the reference pulps (kraft).
Pre-hydrolysed pulps also responded better to oxygen delignification.
Due to this, the cooking process could be interrupted at higher kappa numbers compared to the reference pulps.
The zero span tensile strength was slightly lower for the pre-hydrolysed pulps compared to the reference.
When using anthraquinone (0.1 %) and a sulphidity level of 20%, the screened yield at a certain kappa number was slightly higher than those of normal kraft pulp (sulphidity 40 %).
Abstract (swe): I detta diplomarbete låg fokus på autohydrolys av barrved följt av alkalisk massaframställning.
Som råmaterial användes tall (pinus sylvestris) och gran (picea abies).
Inverkan av olika hydrolys- och kokparametrar undersöktes.

Arbetets mål var att:.

1.
Finna optimala hydrolysförhållanden för att erhålla så mycket hemicellulosa som möjligt och samtidigt undvika oönskade sidoreaktioner.

2.
Finna optimala kokparametrar för de förbehandlade träflisen och bevara en tillfredställande massaproduktion och styrkeegenskaper i den producerade barrvedsmassan.

3.
Undersöka inverkan av antrakinon på massaframställningen.

4.
Sänka sulfiditeten i sulfatmassakoket.

Resultaten visade att den förbehandlade massan uppnådde ett lägre kappatal vid samma H-faktor jämfört med referensmassan.
Förbehandlad massa svarade också bättre på syrgasblekning och därför kunde kokprocessen avbrytas vid en högre H-faktor jämfört med referenskoket.
Nollspännvidddraghållfastheten för förbehandlad massa var en aning lägre än för referensmassan.
Genom att använda antrakinon (0,1 %) och 20 % sulfiditet erhölls en något högre massaproduktion vid ett bestämt kappatal jämfört med sulfatmassa med 40 % sulfiditet utan antrakinon.
ED:2010-10-13
INSSI record number: 41067
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