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Author:Pohjantähti, Juha
Title:Hydrodeoxygenation of distilled tall oil
Publication type:Master's thesis
Publication year:2012
Pages:ix + 110 s. + liitt. 22      Language:   eng
Department/School:Kemian laitos
Main subject:Teknillinen kemia   (Kem-40)
Supervisor:Lehtonen, Juha
Instructor:Linnekoski, Juha ; Niemelä, Marita ; Laitinen, Antero ; Harlin, Ali
OEVS:
Electronic archive copy is available via Aalto Thesis Database.
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Location:P1 Ark Aalto  1953   | Archive
Keywords:tall oil
hydrodeoxygenation
catalyst activity
mäntyöljy
hapenpoisto vedyn avulla
katalyytin aktiivisuus
Abstract (eng): Crude tall oil is a by-product of the kraft pulp process.
Crude tall oil contains fatty and resin acids and unsaponifiables, but there are also impurities, such as sulphur and alkali metals.
Crude tall oil can be refined by distillation to depitched tall oil.
Further refining fractionize tall oil into fatty acids, resin acids or distilled tall oil for example.

Distilled tall oil can be used as a feed stock to produce biofuels.
The compounds of distilled tall oil contain oxygen, which has to be removed before those compounds can be used as traffic fuels.
One method to remove oxygen is hydrodeoxygenation, which can be carried out with many different catalysts.
Sulphided catalysts, such as NiMo/alumina, are recommended to be used in this case, because these catalysts tolerate impurities better than noble metal catalysts.
However, catalysts are deactivated in the process through different mechanisms, such as coke formation on the catalyst surface, poisoning, metal deposition on the surface or sintering of the active phase.

In this thesis, hydrodeoxygenation of distilled tall oil was studied at 350 and 375°C and these experiments were carried out at hydrogen pressure of 50 bar.
The experiments lasted for 18 hours.
Liquid and gas phases were formed during the experiments, and the compounds of these phases (gas + organic phase) were analysed.
After the experiments, the spent catalysts were characterized by measuring carbon and sulphur amounts on the catalyst surface.
In addition, SEM/EDS methods were used for characterization.
Based on the analysis of product compounds and characterization results of the catalyst, conclusions were made concerning the catalyst activity.
Abstract (fin): Raakamäntyöljyä saadaan sellunvalmistuksesta sivutuotteena, joka sisältää rasvahappoja, hartsihappoja ja "saippuoitumattomia" yhdisteitä, mutta mukana on myös epäpuhtauksia, kuten rikkiä Ja alkalimetalleja.
Raakamäntyöljy voidaan jalostaa tislaamalla.
Jatkojalostuksessa poistetaan ensin piki, minkä jälkeen saadaan eri fraktioita, kuten tislattua mäntyöljyä tai rasvahappoja ja hartsihappoja.

Tislatusta mäntyöljystä voidaan valmistaa esimerkiksi biopolttoaineita, mutta tislatun mäntyöljyn yhdisteet sisältävät happea, joka pitää poistaa, jotta yhdisteet soveltuisivat liikennepolttoaineiksi.
Yleensä hapenpoistoon vedyn avulla soveltuvat monet katalyytit, mutta mäntyöljyn sisältämien epäpuhtauksien vuoksi menetelmässä pitää käyttää rikitettyjä katalyytteja, kuten NiMo-katalyyttia alumiinikantajalla.
Katalyytit menettävät aktiivisuuttaan prosessissa ajan mittaan en mekanismien vaikutuksesta, kuten koksin muodostumisesta katalyytin pinnalle, myrkyttymisestä, metallien saostumisesta pinnalle tai aktiivisten alueiden sintrautumisesta.

Työssä tutkittiin tislatun mäntyöljyn hapenpoistoa vedyn avulla 50 bar paineessa 350 ja 375 °C lämpötiloissa.
Kokeet kestivät 18 tuntia.
Kokeessa muodostui sekä neste- että kaasufaasi, joiden koostumusta analysoitiin.
Kokeissa käytettyjä katalyytteja tutkittiin mittaamalla koksin ja rikin määrä katalyytista kokeiden jälkeen.
Lisäksi katalyytin pintaa tutkittiin SEM/EDS-menetelmällä.
Tunnistettujen yhdisteiden ja katalyytin karakterisointitulosten perusteella voitiin tehdä päätelmiä katalyytin aktiivisuuden muutoksista eri koeolosuhteissa.
ED:2012-05-24
INSSI record number: 44633
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