Fischer–Tropsch-tuotteiden erotus

Fischer–Tropsch-synteesi on katalyyttinen prosessi, jolla voidaan tuottaa erilaisia kiinteitä ja nestemäisiä hiilivetyjä. Prosessi on kehitetty jo 1920-luvulla, mutta teollisen mittakaavan sovelluksia on vain harvoja. Synteesissä voidaan käyttää myös uusiutuvia raaka-aineita, mikä on osin lisännyt kiinnostusta tekniikan kehittämistä kohtaan. Insinöörityön aiheena oli Fischer–Tropsch-synteesin tuotteiden erotusmenetelmät. Kirjallisen osan tavoitteena oli luoda katsaus Fischer–Tropsch-vahojen erotus- ja luokittelumenetelmiin. Vahat koostuvat öljyä raskaammista hiilivedyistä, joten niiden erotustekniikat poikkeavat toisistaan. Vahojen fraktiointia on käsitelty kirjallisuudessa verrattain vähän. Työn kokeellisessa osassa tislattiin VTT:n mobiilisynteesikontissa tuotettua synteettistä Fischer–Tropsch-öljyä. Tavoitteena oli erotella öljynäyte kevyempään ja raskaampaan fraktioon sekä tarkastella erotuksen terävyyttä ja näytteen käyttäytymistä erotuksen edetessä. Kevyemmän ja raskaamman fraktion raja asetettiin niin, että dodekaani oli kevyemmän fraktion raskain komponentti. Dodekaanin korkean kiehumispisteen takia tislaus suoritettiin alipaineessa. Erotuksen onnistumista ja näytteiden koostumusta arvioitiin kaasukromatografisen analyysin avulla. Lisäksi työssä analysoitiin kaupallisen parafiiniöljyn ja valkovaseliinin koostumusta analyyttisin keinoin. Öljynäytteen tislaaminen onnistui melko hyvin. Kokeellisessa toiminnassa ilmeni haasteita, mutta erotuksen voidaan katsoa onnistuneen. Prosessin käyttäytymisestä tehtiin havaintoja, jotka ovat yhteneviä kirjallisuuden kanssa.Fischer–Tropsch synthesis is a process used to produce different kinds of solid and liquid hydrocarbons. It was originally developed in 1920’s in Germany. While it was utilized in wartime efforts, the industrial applications remain rare. Renewable materials can be used as raw materials to produce products ranging from gasoline to waxes. It may have helped to spark interest in developing the process. The subject of this project was the separation methods of Fischer-Tropsch synthesis products. The practical part of the thesis project consisted of distillation and analysis of a synthesis oil sample. The behavior of the distillation bottom was also observed. The sample was acquired from MOBSU-synthesis unit. Separation was arranged so that the heaviest compo nent of the distillate was dodecane. Due to relatively high boiling point of dodecane, the distillation was conducted at lowered pressure. The samples were subjected to gas chromatographic analysis in order to observe the achieved separation sharpness. Commercial paraffin oil and white petrolatum were also analyzed. The theoretical part of the thesis project examined the various techniques of wax fractionation. Characterization methods and standards were also explored. There is a relatively small amount of literature concerning wax fractionation. Methods employed in liquid hydrocarbon separation are covered more widely. The practical part of this thesis project succeeded fairly well. Challenges in distillation provided valuable insight into hydrocarbon separation and experimental work in general. The results were in line with literature. In the theoretical part, noteworthy processes, characterization methods and standards are presented

Atomikerroskasvatetut fotokatalyyttiset titaanidioksidiohutkalvot

Ensuring adequate air quality is integral to healthy living. Since in modern societies the majority of time is spent indoors, understanding indoor air pollution and the means of air purification are of great importance. Adverse health effects are induced by volatile organic compounds (VOC) that originate from everyday activities and our surroundings. Photocatalysis is a radiation-activated chemical transformation that can be used to decompose organic pollutants into harmless constituents. However, existing air purification solutions employing photocatalysis often rely on UV light limiting the use of solar radiation. Titanium dioxide is a popular photocatalyst material, but it requires modification to its electronic properties to respond to visible light. An established approach is to introduce atoms of other dopant elements into the titania lattice. Atomic layer deposition (ALD) is a thin film deposition technique widely studied especially in metal and metal oxide research. Following from the principle of sequential saturation of the surface, control over the size and composition of the film may reach atomic level. Since the chemical configuration of a doped TiO2 film is of utmost importance to successful modification, ALD is an excellent tool to examine suitable photocatalytic TiO2 chemistries. Furthermore, thin solid films of catalytically active material would have a distinguished advantage for deployment in real-life settings over their powderous counterparts. The literature review of this thesis explores the semiconductor photocatalysis with an eye on its suitability to indoor air purification. The motivation is to give the reader a view on the air quality issue, the existing technological solutions and how a thin film photocatalyst could supplement the field. Titanium dioxide doping concepts are introduced to elucidate the rationale behind the experimental efforts. The experimental part describes a development project to deposit visible-light responding photocatalysts. Titanium dioxide thin films co-doped with nitrogen and zinc/fluorine were grown on steel plates. An in-house built reactor system was used to study acetaldehyde degradation under irradiation. Unfortunately, the reactor experienced a malfunction, rendering a large part of the results futile. Moreover, months of valuable time were lost in chasing a mirage of fallacious data. In the end an ALD grown photocatalyst responding to visible light could not be materialized

Atomic Layer Deposited TiO2 on a Foam-Formed Cellulose Fibre Network - Effect on Hydrophobicity and Physical Properties

Climate change and plastic pollution challenge us to develop alternatives for fossil-based plastics, and cellulose-based materials are excellent candidates for this. Foam forming technology for cellulose fibre products increases process efficiency, widens the raw materials base, and enables low-density structures from fibres. Low-density cellulose-based materials can be used,for example,for packaging, insulation, and construction materials. However, to achieve optimal performance, the resistance against moisture and mechanical compression ought to be enhanced. In this research, the effect of atomic layer deposited (ALD) titanium dioxideon four foam-formed cellulose-based structureswas studied. The hydrophobicity of these materials was analyzed with water contact angle measurements. Moisture content and mechanical properties were tested at high humidity (50% RH and 90% RH) by analyzing moistureuptakeand compression strength. Furthermore, the morphology and microstructures were evaluated with scanning and transmission electron microscopy (SEMandTEM). ALD treatment changedthe hydrophilic materials to hydrophobic with 5 cycles of TiO2forall four substrates. The effect on moisture content was milder but was observed strongest with unrefined and partly refined samples at 50% RH. A clear trend between moisture content and mechanical strength was detected sincethe compression strength increased with decreasing moisture content

Atomic Layer Deposited TiO2 on a Foam-Formed Cellulose Fibre Network - Effect on Hydrophobicity and Physical Properties

Climate change and plastic pollution challenge us to develop alternatives for fossil-based plastics, and cellulose-based materials are excellent candidates for this. Foam forming technology for cellulose fibre products increases process efficiency, widens the raw materials base, and enables low-density structures from fibres. Low-density cellulose-based materials can be used,for example,for packaging, insulation, and construction materials. However, to achieve optimal performance, the resistance against moisture and mechanical compression ought to be enhanced. In this research, the effect of atomic layer deposited (ALD) titanium dioxideon four foam-formed cellulose-based structureswas studied. The hydrophobicity of these materials was analyzed with water contact angle measurements. Moisture content and mechanical properties were tested at high humidity (50% RH and 90% RH) by analyzing moistureuptakeand compression strength. Furthermore, the morphology and microstructures were evaluated with scanning and transmission electron microscopy (SEMandTEM). ALD treatment changedthe hydrophilic materials to hydrophobic with 5 cycles of TiO2forall four substrates. The effect on moisture content was milder but was observed strongest with unrefined and partly refined samples at 50% RH. A clear trend between moisture content and mechanical strength was detected sincethe compression strength increased with decreasing moisture content

Atomic Layer Deposited TiO2 on a Foam-Formed Cellulose Fibre Network – Effect on Hydrophobicity and Physical Properties

Climate change and plastic pollution challenge us to develop alternatives for fossil-based plastics, and cellulose-based materials are excellent candidates for this. Foam forming technology for cellulose fibre products increases process efficiency, widens the raw materials base, and enables low-density structures from fibres. Low-density cellulose-based materials can be used, for example, for packaging, insulation, and construction materials. However, to achieve optimal performance, the resistance against moisture and mechanical compression ought to be enhanced. In this research, the effect of atomic layer deposited (ALD) titanium dioxide on four foam-formed cellulose-based structures was studied. The hydrophobicity of these materials was analyzed with water contact angle measurements. Moisture content and mechanical properties were tested at high humidity (50% RH and 90% RH) by analyzing moisture uptake and compression strength. Furthermore, the morphology and microstructures were evaluated with scanning and transmission electron microscopy (SEM and TEM). ALD treatment changed the hydrophilic materials to hydrophobic with 5 cycles of TiO2 for all four substrates. The effect on moisture content was milder but was observed strongest with unrefined and partly refined samples at 50% RH. A clear trend between moisture content and mechanical strength was detected since the compression strength increased with decreasing moisture content

Constructing Spacecraft Components Using Additive Manufacturing and Atomic Layer Deposition : First Steps for Integrated Electric Circuitry

Funding Information: We thank the European Space Agency (ESA), who has supported parts of this research as part of the HighPEEK project (ESA Contract No. 4000127834/19/UK/AB). In particular, Ugo Lafont and Paul Greenway (ESA) have our gratitude. We also deeply appreciate the help given by Daniel Leese (exchange student at Aalto University), Kirsi Kukko, Ashish Mohite and Olli Knuuttila (Aalto University), Lorenz Schmuckli and Pekka Rummukainen (Aalto University, retired), and Katja Väyrynen and Marko Vehkamäki (University of Helsinki). Publisher Copyright: © 2021 American Society of Civil Engineers.Many fields, including the aerospace industry, have shown increased interest in the use of plastics to lower the mass of systems. However, the use of plastics in space can be challenging for a number of reasons. Ultraviolet radiation, atomic oxygen, and other phenomena specifically associated with space cause the degradation of polymers. Here we show a path toward creation of space-grade components by combining additive manufacturing (AM) and atomic layer deposition (ALD). Our method produced ALD Al2O3 coated thermoplastic parts suitable for space applications. The highlight of this work is a significant reduction in outgassing, demonstrated using residual gas analyzer (RGA) sampling. Compared to uncoated parts, the ALD Al2O3 coating decreased the outgassing of polyether ether ketone (PEEK), acrylonitrile butadiene styrene (ABS), polycarbonate (PC), and nanodiamond-doped polylactide (ND-PLA) by 46%, 49%, 58%, and 65%, respectively. The manufacturing method used in this work enables the use of topology optimization already in the early concept creation phase. The method is ideally suited for spacecraft applications, in which the volume and mass of parts is critical, and could also be adapted for in-space manufacturing. (c) 2021 American Society of Civil Engineers.Peer reviewe