663 research outputs found
Hydrodeoxygenation of distilled tall oil
No full textCrude 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.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
Hydrotreating of tall oils on a sulfided NiMo catalyst for the production of base-chemicals in steam crackers
Get PDFDevelopment of new and innovative products through efficient technologies is essential for the implementation of sustainable developments in highly competitive chemical industries. Based on this context, raw materials originating from biomass have been widely used for the production of chemicals and materials.
Steam cracking of bio-based or renewable feedstocks in a conventional steam cracking set-up is identified as a promising approach for the sustainable production of base-chemicals. In a two-step process for the production of base-chemicals, firstly, bio-derived feedstock is upgraded into a more suitable feedstock which comprises mainly paraffin range hydrocarbons with a lower oxygen content than the original feedstock; secondly, the upgraded feedstock is converted into base-chemicals by conventional steam cracking technology. This research work identifies wood-derived tall oil as a potential feedstock for the production of base-chemicals by catalytic upgrading and steam cracking methods.
The main aim of this work was to carry out the catalytic hydrotreating of tall oil feedstocks such as tall oil fatty acid (TOFA), distilled tall oil (DTO) and crude tall oil (CTO) on a commercial, sulfided NiMo catalyst at different process conditions.
The effects of space time and process temperatures on the distribution of products from the hydrotreatment of different tall oil feeds were investigated.
Hydrotreating chemistry of oxygenates in tall oil were assessed based on the achieved conversion of reactants and product distribution under the investigated conditions. Furthermore, the steam cracking of hydrodeoxygented tall oil (HDO-tall oil) feeds was carried out, and evaluation of the yield of olefins in comparison with conventional steam cracking feeds such as naphtha and natural gas condensate (NGC)
Hydrotreating reactions of tall oils over commercial NiMo catalyst
No full textCatalytic hydrotreating is an attractive method for upgrading bio-derived oils into renewable feedstocks with less oxygen content, suitable for producing valuable hydrocarbons through various petro-refinery processes. This study evaluates the catalytic activity of a commercial alumina (Al2O3) supported NiMo catalyst for hydrotreating tall oil feeds such as crude tall oil (CTO), distilled tall oil (DTO), and tall oil fatty acid (TOFA). Catalytic experiments carried out in a bench-scale fixed bed reactor set-up at different process conditions [space velocity (1–3 h−1), temperature (325–450°C), and H2 pressure (5 MPa)] produced a wide-range of products from tall oil feeds. Hydrotreating of TOFA produced highest yield of n-alkanes (>80 wt%) compared to DTO and CTO hydrotreating. A high conversion of fatty acids and resin acids was obtained in DTO hydrotreating. In CTO hydrotreating, a drop in conversion of fatty acids and resin acids was observed especially at the lowest temperature tested (325°C). The study revealed that there are various deoxygenation pathways preferential at different hydrotreating temperatures. As an example for TOFA, the decarboxylation route is dominant over the hydrodeoxygenation route at high temperatures (>400°C)
Mflme Juha
No full textThis collaborative project began when the Ford Foundation approached Gerry Mulgrew (director of Communicado Co. theatre group), in search of experienced arts practitioners to form links and opportunities with the Tanzanian theatre group, Parapanda Arts Lab. Mulgrew chose McIntyre to help him develop workshop techniques that involved ‘performed’ drawing and storytelling. The aim was to use these techniques to enable creative conversations between actors, that cut across cultural and linguistic boundaries. McIntyre was invited to undertake a residency with Communicado Co. in order to explore both conventional theatrical approaches to improvisatory workshop and those related to the placement and community-based activities he organises for fine art undergraduates at Northumbria. The residency generated the workshop process that equipped McIntyre to be Visual Art Director of the multi-media performance Mflme Juha. McIntyre also used the drawing practices on which the workshop technique was constructed to explore the visualisation of short stories for children. Seven Stories (the National Centre for Children’s Books) commissioned McIntyre to contribute to a documentary TV programme (McIntyre worked with author David Almond [winner of the Whitbread award], actor Kevin Wheatley [Inspector Morse and Auf Weidesein Pet] and the director/producer Lesley Duncanson), to help describe the development of a narrative idea through the contrasting acts of writing, drawing and reading. The result was ‘The Savage’ (screened on ITV, 3rd September 2006). As a follow-up, McIntyre was invited to be artist-in-residence for ‘the Big Draw’, a weekend event in which visual narratives were developed in partnership with writers and actors
Hydrotreating reactions of tall oils over commercial NiMo catalyst
No full textCatalytic hydrotreating is an attractive method for upgrading bio-derived oils into renewable feedstocks with less oxygen content, suitable for producing valuable hydrocarbons through various petro-refinery processes. This study evaluates the catalytic activity of a commercial alumina (Al2O3) supported NiMo catalyst for hydrotreating tall oil feeds such as crude tall oil (CTO), distilled tall oil (DTO), and tall oil fatty acid (TOFA). Catalytic experiments carried out in a bench-scale fixed bed reactor set-up at different process conditions [space velocity (1-3 h-1), temperature (325-450°C), and H2 pressure (5 MPa)] produced a wide-range of products from tall oil feeds. Hydrotreating of TOFA produced highest yield of n-alkanes (>80 wt%) compared to DTO and CTO hydrotreating. A high conversion of fatty acids and resin acids was obtained in DTO hydrotreating. In CTO hydrotreating, a drop in conversion of fatty acids and resin acids was observed especially at the lowest temperature tested (325°C). The study revealed that there are various deoxygenation pathways preferential at different hydrotreating temperatures. As an example for TOFA, the decarboxylation route is dominant over the hydrodeoxygenation route at high temperatures (>400°C)
Hydrogen solubility measurements of analyzed tall oil fractions and a solubility model
No full textKnowledge of hydrogen solubility in tall oil fractions is important for designing hydrotreatment processes of these complex nonedible biobased materials. Unfortunately measurements of hydrogen solubility into these fractions are missing in the literature. This work reports hydrogen solubility measured in four tall oil fractions between 373 and 597 K and at pressures from 5 to 10 MPa. Three of the fractions were distilled tall oil fractions their resin acids contents are respectively 2, 20 and 23 in mass-%. Additionally one fraction was a crude tall oil (CTO) sample containing sterols as the main neutral fraction. Measurements were performed using a continuous flow synthetic isothermal and isobaric method based on the visual observation of the bubble point. Composition of the flow was changed step-wise for the bubble point composition determination. We assume that the tall oil fractions did not react during measurements, based on the composition analysis performed before and after the measurements. Additionally the densities of the fractions were measured at atmospheric pressure from 293.15 to 323.15 K. A Henry's law model was developed for the distilled tall oil fractions describing the solubility with an absolute average deviation of 2.1%. Inputs of the solubility model are temperature, total pressure and the density of the oil at 323.15 K. The solubility of hydrogen in the CTO sample can be described with the developed model with an absolute average deviation of 3.4%. The solubility of hydrogen increases both with increasing pressure and/or increasing temperature. The more dense fractions of the tall oil exhibit lower hydrogen solubility in comparison to the less dense fractions. The increase in the density of a fraction corresponds to an increased resin acid and sterol content of the sample. Sterols and resin acids exhibit lower hydrogen solubility in comparison to fatty acids
Endpoint Sobolev bounds for fractional Hardy–Littlewood maximal operators
No full textFunding Information: I would like to thank my supervisor, Juha Kinnunen, for all of his support. I would like to thank Olli Saari for introducing me to this problem. I am also thankful for the discussions with Juha Kinnunen, Panu Lahti and Olli Saari who made me aware of a version of the coarea formula [, Theorem 3.11], which was used in the first draft of the proof, and for discussions with David Beltran, Cristian González-Riquelme and Jose Madrid, in particular about the centered fractional maximal operator. The author has been supported by the Vilho, Yrjö and Kalle Väisälä Foundation of the Finnish Academy of Science and Letters. Publisher Copyright: © 2022, The Author(s).Let 0 0 the fractional maximal function does not use certain small balls. For α= 0 the proof collapses.Peer reviewe
Median-Type John–Nirenberg Space in Metric Measure Spaces
No full textFunding Information: The author would like to thank Juha Kinnunen and Riikka Korte for valuable discussions. The author would also like to thank the anonymous referee for carefully reading the paper and for constructive comments. The research was supported by the Academy of Finland. Publisher Copyright: © 2022, The Author(s).We study the so-called John–Nirenberg space that is a generalization of functions of bounded mean oscillation in the setting of metric measure spaces with a doubling measure. Our main results are local and global John–Nirenberg inequalities, which give weak-type estimates for the oscillation of a function. We consider medians instead of integral averages throughout, and thus functions are not a priori assumed to be locally integrable. Our arguments are based on a Calderón–Zygmund decomposition and a good-λ inequality for medians. A John–Nirenberg inequality up to the boundary is proven by using chaining arguments. As a consequence, the integral-type and the median-type John–Nirenberg spaces coincide under a Boman-type chaining assumption.Peer reviewe
The Diary, the Typewriter and Representative Reality in the Genesis of Juha Mannerkorpi's Päivänsinet
Get PDFTämä artikkeli käsittelee siirtymää päiväkirjan pitämisestä tulevan julkaistavan teoksen kirjoittamiseen tarkastelemalla Juha Mannerkorven Päivänsinet: muuan loppukesän merkintöjä (1979) -teoksen syntyprosessia. Päiväkirjaromaani kertoo vakavasti sairaasta kertojasta, joka tunnollisesti seuraa päivänsinen kasvua laskien, mittaillen ja kirjoituskoneella ylöskirjaten sen päivittäin puhkeavia kukkia. Yhdistämällä geneettistä kritiikkiä Philippe Lejeunen ajatuksiin päiväkirjasta, antifiktiosta ja päiväkirjaefektistä artikkelissa analysoidaan Päivänsinissä toistuvia metapoeettisia huomioita kirjoituskoneen käytöstä ja faktan ja fiktion suhteesta päiväkirjan kirjoitusprosessin ja sen romaaniksi uudelleenkirjoittamisen kontekstissa. Yksityiskohtainen käsikirjoitusten tarkastelu tuo esille, ettei kirjoituskone ole läpinäkyvä väline, jonka avulla heikkonäköinen tekijä saattoi kirjoittaa, vaan että koneella kirjoittaminen fyysisenä toimintana vaikutti Mannerkorven tekstin sisältöön monin tavoin. Sen lisäksi, että artikkeli valottaa Mannerkorven teosten monia kokeellisia puolia Päivänsinien syntyprosessien tarkastelu lisää ymmärrystämme kirjoitusvälineiden vaikutuksesta päiväkirjan pitämiseen ja kirjalliseen työskentelyyn.This article investigates the transition from keeping a diary to writing a future published work with reference to the genetic process of Päivänsinet: muuan loppukesän merkintöjä (1979) by Finnish author and translator Juha Mannerkorpi. The diary novel is about a seriously ill narrator who watches the growth of a morning glory, meticulously counting, measuring and registering the daily unravelling flowers with the help of a typewriter. In combining genetic criticism with Philippe Lejeune’s ideas on the diary, antifiction and the diary effect, the article analyses the frequent metapoetic remarks upon the use of the typewriter and the relationship between fact and fiction in the context of the diary-writing process and its subsequent rewriting as a novel. Upon close inspection of the manuscripts it becomes clear that the typewriter was not a transparent medium that helped the weak-sighted author to write, but that the physical act of typing influenced the content of Mannerkorpi’s text in many respects. In addition to shedding light on many experimental features of Mannerkorpi’s works, this study on the genesis of Päivänsinet widens current understanding concerning the impact of writing tools on diary-keeping and literary writing.Peer reviewe
- …
