<p>In order to secure the energy supply to an increasing population and at the same time limit the damage to Earth, i.e. avoiding a fatal climate change as a result of anthropogenic emissions of greenhouse gases (primarily CO₂₎, immediate action is necessary. This includes reducing the energy consumption, increasing the energy conversion efficiency, and using renewable energies. The transport sector is the one most dependent on fossil energy and it stands for a significant part of the energy consumption in the world. For instance, in EU-25 transportation stands for 30 % of the total final energy consumption and relies to 98 % on oil. Being the only renewable energy possible to convert into liquid fuels biomass, as a means for reducing the CO₂ emissions from the transport sector, will play an important role in the near future.</p><p>The conversion of biomass into transportation fuels is preferentially done via gasification followed by the fuel synthesis. The whole production chain from biomass to final fuel is very dependent on R&D, in order to become competitive with the fossil fuels. Fischer-Tropsch (FT) diesel made from biomass is a viable option for reducing the CO₂ emissions from transportation since it may be blended with conventional diesel in any concentration. Furthermore, since its composition is almost the same as of petroleum-based diesel (although cleaner) the same distribution system and engines may be used, which facilitates its introduction on the market. This thesis presents the results of the laboratory work performed in 2003 – 2007 at the Department of Chemical Technology, KTH, and at the Department of Chemical Engineering, NTNU (the Norwegian University of Science and Technology) in Trondheim. Part of the work has been performed in close cooperation with the Department of Chemical and Biological Engineering at Chalmers University of Technology.</p><p>All FT experiments were performed in a fixed-bed reactor at 210 ºC and 20 bar. Pure mixtures of H₂, CO and N₂ were used as feed to the reactor. Steam was also occasionally introduced. Selectivity to C₅₊ was used as a measure of the catalysts’ ability to grow long-chain hydrocarbons, which is desirable when diesel is the product aimed for.</p><p>The first part of the thesis deals with the direct conversion of a H_2-poor syngas, which is obtained upon gasification of biomass, into FT hydrocarbons. “H_2-poor” means that the H₂/CO ratio is lower than what is required by the stoichiometry (~ 2.1) of the FT synthesis (reaction 1). In order to increase the H₂/CO ratio to the required one, internal water-gas-shift (WGS) is needed (reaction 2).</p><p>FT: CO + 2H2  “-CH2-“ + H2O (1)</p><p>WGS: CO + H2O  CO2 + H2 (2)</p><p>The H₂/CO usage ratio has been used as a measure for the internal WGS activity, it is defined as follows:</p><p>where S is the selectivity (of total C-containing products), and the factor <i>F</i> indicates the number of H₂ moles required for one CO mole to form the product (e.g. for producing high molecular weight <i>n</i>-paraffins, 2 moles of H₂ per mole of CO are required). For the fraction C₂ – C₄, F will have different values depending on the selectivity to C₂, C₃ and C₄, and it also depends on the olefin/paraffin ratios for those hydrocarbons. In order to reach the highest once-through conversion of the syngas, the H₂/CO usage ratio should be equal to the inlet H₂/CO ratio. The lower the usage ratio, the higher the relative WGS activity.</p><p>The combined FT and WGS reactions with H₂-poor syngas have been tested for 12 wt% Co and 12 wt% Co – 0.5 wt% Re catalysts supported on γ-Al₂O₃. It was found that with lower H₂/CO ratios in the feed, the syngas conversion and the CH₄ selectivity decreased, while the C₅₊ selectivity and olefin/paraffin ratio for C₂-C₄ increased slightly. The WGS activity was low for all catalysts, implying a H₂/CO usage ratio close to the stoichiometric one (2.1), even for inlet H2/CO ratios of 1.5 and 1.0.</p><p>By incorporating significant amounts of Fe (20 % of total metal) in the Co catalyst referred to above (by co-impregnation) in order to achieve a 12 wt% bimetal loading on γ-Al₂O₃, a slightly lower usage ratio was obtainable (1.92) for an inlet ratio of 1.0 for dry conditions. Different Fe:Co ratios ranging from 100 % Fe to 100 % Co (12 wt% bimetal) were tested for an inlet H₂/CO ratio of 1.0. The characterisation results indicated that Fe was enriched at the surface, hence covering the more FT-active Co sites, even at low percentage Fe. Not even upon significant replacement of Co by Fe (≥ 20 %) were the usage ratios for dry conditions lowered to any significant extent.</p><p>The WGS reaction at the low temperature used could be boosted by addition of external water. However, since the catalysts with the highest WGS activity had surface enrichment of Fe, high water partial pressures negatively affect the FT rate and also lead to rapid deactivation by re-oxidation of the FT-active iron phases (iron carbides) or by sintering. Surprisingly, also the WGS activity rapidly deactivated at high partial pressures of water, although Fe₃O₄ is believed to be the WGS-active phase. Possibly, surface oxidation of Fe₃O₄ into γ-Fe₂O₃ may take place during these water-rich conditions.</p><p>The WGS reaction (reaction 2) is thermodynamically favoured at low temperatures. However, the WGS kinetics over the tested catalysts is far too slow at the FT reaction temperature used in typical low-temperature FT (LTFT) applications, with diesel as the desired product.</p><p>The second part of this thesis deals with the hydrocarbon selectivity over Co-based catalysts in the FT synthesis with stoichiometric H₂/CO feed. An alternative catalyst preparation technique, the microemulsion (ME) technique, was used as a complement to the conventional incipient wetness (IW) impregnation. A great deal of effort was put into the development of the synthesis of Co particles of monodisperse size in a ME and the subsequent deposition of these onto a porous support material. By using the ME technique it was possible to prepare relatively small Co particles in a large-pore support such as TiO₂, which is not an easy task using the conventional impregnation technique.</p><p>With the prepared ME catalyst on TiO₂ it was possible to study the effect of Co particle size on FT selectivity irrespective of the pore size of the support. It was found that, at least for Co particles above 10 nm, it is not the Co particle size that is the principal parameter determining the selectivity of a catalyst, but rather the physical and/or chemical properties of the support.</p><p>Due to the smaller Co particle size (~ 12 nm) of the ME-TiO₂ catalyst as compared to a corresponding IW catalyst (~ 26 nm) supported on TiO₂, the FT activity of the former was 100 % higher as fresh catalyst. After 120 h on stream the ME catalyst still gave 60 % higher rate to C₅₊ (expressed as gC₅₊/gcat,h) compared to both an IW-TiO₂and an IW-γ-Al₂O₃catalyst, all catalysts having the same composition (12 wt% Co, 0.5 wt% Re).</p>

<p>To fully understand the elementary reactions behind the ignition of automotive fuels the interaction between the fuel components must be known. The ignition initiation is most often caused by loss of an H radical from a reactive fuel molecule, for example n-heptane. The formed alkyl radical is prone to react with oxygen under lean conditions. However, it can also abstract hydrogen from other fuel molecules, hence activating more unreactive species. This type of reactions is called cooxidation reactions and including it in combustion mechanisms improve ignition delay predictions in a wide range of experiments, for Primary Reference Fuel mixtures and toluene/heptane mixtures. Example of such reactions are</p><p>C7H_15• + C₈H₁₈ = C7H₁₆+ C₈H_17•</p><p>C7H₁₅OO• + C₈H₁₈= C₇H₁₅OOH+ C₈H_17•</p><p>Adding cooxidation reactions also significantly improves prediction of the general trend of auto-ignition phasing as function of operating conditions in Homogeneous Charge Compression Ignition, HCCI, engine combustion.</p><p>The effect of NO addition on engine combustion has also been studied in this work. A novel strategy to control ignition onset in HCCI engines is to retain exhaust gases in the cylinder to control the cylinder temperature. While this not only controls the engine temperature it also introduces NOx in the cylinder. The NO will advance ignition onset by several crank angle degrees at concentrations below 10 ppm. This is because NO activates HO₂ in the reaction: HO_2• + NO = OH• + NO₂. At higher concentrations the ignition onset is not as advanced and in the PRF case even retarded. This is because NO has cool flame-inhibiting effects.</p><p>Kinetic modelling can also be used to predict combustion efficiency in catalytic combustors for power generation. It was shown that at high pressures the number of free sites decreases which limits the combustion efficiency. Thus a hybrid concept could be used where only a fraction of the air and fuel is burned catalytically.</p>

<p>SAMMANFATTNING</p><p>De textilindustrier som finns i u-länderna är oftast tekniskt enkla i sin utformning, bl.a. med avseende på det färgade avloppsvatten som släpps ut utan rening. Detta ger upphov till miljöförstöring pga. att vattnet innehåller höga salthalter, alkalinitet och stark färg.</p><p>Det ger även upphov till hälsoproblem då flera av de färger som används vid textilfärgning kan blir enzymatiskt nedbrutna i människans matsmältningssystem och bilda cancerogena substanser.</p><p>Syftet med denna studie var att undersöka om skogsflis, fetvadd och vitrötesvamp kan användas för att bryta ner färger som används vid textilfärgning i synnerhet i fattigare länder där problemen med utsläppen från textilfärgningsfabriker är stort. Huvudtanken med projektet är att med små medel förbättra miljö och hälsoförhållandena där textilindustrin befinner sig.</p><p>I denna studie användes tre olika textilfärger tillsammans med skogsflis, fetvadd och vitrötesvamp. I försöken med skogsflis har avfärgningen av textilfärgerna varit mycket effektiv. Detta har kunnat bekräftas genom analys med spektofotometer och genom visuella iakttagelser. Försök har även gjorts för att se om skogsflis kan återanvändas. Det konstaterades att den kunde återanvändas. Försöket gav bättre resultat än om man använder ny skogflis. Detta konstaterades genom att avfärgningen gick snabbare med använd skogsflis än med ny skogsflis.</p><p>Försök gjordes med vitrötesvamp (Bjerkandera sp. BOL-13) på maltagarplattor innehållande textilfärg. Även vitrötesvamp var effektiv vid avfärgning av textilfärgerna.</p><p>Slutsatser som vi kan dra av vår studie är att användning av skogsflis och vitrötesvamp är effektiv vid avfärgning av textilvatten. Denna metod har stor potential för vidare utveckling, för att sedan kunna användas där billiga och enkla metoder behövs.</p>

Sammanfattning Titel: Effektiv Batchdokumentation Handledare: Annette Elmqvist Examinator: Sven Hamp Problemformulering: De problemformuleringar varit utgångspunkt för arbetet är: • Kan dokumentationen struktureras på ett bättre sätt och effektiviseras. • Kan befintlig dokumentation delas upp för att skapa effektivare flöde Syfte och mål: Syftet med detta examensarbete är att utveckla en bättre struktur för GMP styrande dokumentation avseende tillverkningsmetod, kontrollprotokoll och instruktioner för tillverkning av valt intermediat i ett automatiserat system som uppfyller kraven på både lättförstålighet och effektivitet. Metod: Genom intervjuer med operatörer inom företaget och på andra företag ta fram nya rutiner för utarbetande och effektivisering av dokumentationsprocessen. Genom litteraturstudier definiera väsentlig krav på dokumentationsprocessen enligt GMP. Slutsatser: Det går att effektivisera dokumentationsprocessen för vald tillverkning. Det går att dela upp dokumentationen och särskilja uppvägning och analyser. Ansatserna i problemformuleringen kan med rimlig arbetsinsats uppnås. En förändring av dokumentationsprocessen är företagsekonomiskt motiverad och samtidigt viktig för att den underlättar kvalitetsuppföljning genom dokumentationsanalys. Målgrupp: Rapporten är i första hand ämnad för produktions- och kvalitetsledningen för implementering i organisationen. Men den kan även utgöra stöd för de grupper som kan komma att få i uppdrag att se över olika dokumentationsförfaranden inom företaget.

The treatment of municipal solid waste (MSW) in Sweden has changed during the past decades due to national legislation and European Union directives. The former landfills have more or less been abandoned in favour of material recycling and waste incineration. On a yearly basis approximately 2.2 million tonnes waste are incinerated in Sweden with heat recovery and to some extent also with electricity generation, though at a low efficiency. It is desirable to alter this utilisation and instead employ MSW as fuel in a fluid bed gasification process. Then electrical energy may be produced at a much higher efficiency. However, MSW contain about 1 % chlorine in the form of ordinary table salt (NaCl) from food scraps. This implies that the tar cracking catalyst, dolomite, which is normally employed in gasification, will suffer from poisoning if applied under such conditions. Then the tar cracking capacity will be reduced or vanish completely with time. Consequently, an alternative catalyst, more resistant to chlorine, is needed. Preliminary research at KTH has indicated that iron in its metallic state may possess tar cracking ability. With this information at hand and participating in the project “Energy from Waste” an experimental campaign was launched. Numerous experiments were conducted using iron as tar cracking catalyst. First iron sinter pellets from LKAB were employed. They were reduced in situ with a stream of hydrogen before they were applied. Later iron-based granules from Höganäs AB were tested. These materials were delivered in the metallic state. In all tests the KTH atmospheric fluidised bed gasifier with a secondary catalytic reactor housing the catalytic material was deployed. Mostly, the applied fuel was birch. The results show that metallic iron possesses an intrinsic ability, almost in the range of dolomite, to crack tars. Calculations indicate that iron may be more resistant to chlorine than dolomite. The exploration of metallic iron’s excellent tar cracking capacity led to the innovative manufacture of an iron catalytic tar cracking filter as well as a general knowledge of its tar cracking capacity. This filter with dual functionality would be a general improvement of the gasification process since it among other things would make the process denser. / QC 20110428

No description available.

NOx emissions from diesel vehicles are a currently well-discussed matter due to the related health and environmental issues. At the same time, diesel vehicles are an important part of transportation in society as diesel engines are more fuel efficient than gasoline engines. NOx emissions are regulated by European standards, this put demands on a well-functioning exhaust gas aftertreatment system that lower the NOx emissions for the whole lifetime of the vehicle. One of the most effective solutions is by reduction of NOx with ammonia over a SCR catalyst. Cu/SSZ-13 zeolite has shown to be a promising SCR catalyst. SCR catalysts are however deactivated by several different mechanisms, where sulfur poisoning is a significant mechanism. There are many different factors that will influence how sulfur impacts the catalyst. Different catalyst materials are more or less sulfur tolerant. The form of sulfur is important as well as both temperature and availability of ammonia. It is thus important to investigate how sulfur affects the SCR catalyst.   The aim of this master’s thesis project was to develop a method for measuring sulfur tolerance of different SCR catalysts and to gain understanding of sulfur poisoning of Cu/SSZ-13 catalysts. A literature study on sulfur poisoning of SCR catalysts with a focus on Cu/SSZ-13 was first carried out. Followed by an experimental part in a rig at Scania CV AB in Södertälje, where the method was developed.   A method that can be used for testing SCR catalysts on sulfur tolerance after SO2 exposure was successfully achieved. The experimental procedure was designed to consist of eight steps, including de-greening, sulfur poisoning, regeneration at two temperatures and catalyst activity test after each step. Clear differences on NOx conversion between fresh, sulfated and regenerated catalysts are observed when using the method. Three different sulfation temperatures were evaluated where the lower sulfation temperatures, 220 ⁰C and 280 ⁰C, caused a larger impact on NOx conversion compared to sulfation at 350 ⁰C. Two different catalysts were compared on their NOx conversion over fresh, sulfated and regenerated catalysts. The method was correlated to engine aging with respect to sulfur exposure, sulfur capture, gas and temperature conditions and activity loss. The method corresponds to approximately 430 000 km driving based on sulfur exposure over the catalyst. The lab method is best comparable to a SCR catalyst located first in the exhaust gas aftertreatment system in a vehicle, based on two conclusions. (1) Poisoning is performed with only SO2. (2) Standard SCR conditions occur in the activity test.   The method should be further developed by enabling testing of NOx conversion at fast and slow SCR conditions. More work should be carried out on the correlation to vehicle aging by comparision with engine aged catalysts.

The depletion time for fossil fuels calculated from 2009 is 35 years for oil, 37 years for gas and 107 years for coal. Hence, it has become essential to reduce the dependence on fossil fuels by switching over to renewable resources. This in turn will also help in combating the negative effects on the environment like global warming. Thermochemical processes such as pyrolysis and gasification of biomass are considered the most efficient technology for converting biomass to useful energy carriers. Cortus Energy AB is a Swedish company that has developed a patented gasification technology called WoodRoll ® for gasification of fuels derived from biomass. However, ash in a thermochemical conversion process can cause corrosion, sintering, slag and poisoning of catalysts, which leads to operational problems. In addition, heavy metals such as Zn, Pb and Cd are environmentally problematic. These metals contribute to environmental pollution by contaminating the soil, which in turn can harm humans and the ecosystem via the food chain. The undesired elements should therefore be identified to minimize their impact on the overall thermochemical process and to reduce the emission of these harmful substances. The objective of this master thesis project, on behalf of Cortus Energy AB, was to investigate possible key numbers that can be used to describe and predict how the ash behaves in their patented WoodRoll® process. The key numbers that have been identified are empirically developed based on experience of coal combustion. These key numbers are regularly used for fuel derived from biomass by companies specializing in analyzing, although knowledge about whether they can actually be used on biomass is limited. In order to ensure that the use of these for biomass is correct, they must be experimentally verified in the future. In addition, a theoretical investigation is conducted to study which species can form and in what phase this occurs. The investigation reveals that there are no clear trends for how the inorganic elements behave since contradicting results from different studies have been reported. Formation of species and their phase depends on several parameters such as temperature, heating rate, particle size, volatility, quantity and interaction between the elements in the biomass. The thesis project ends with a mass balance model on selected inorganic elements for wood residues, as well as for bark. The model could be a tool for Cortus Energy AB to identify approximately how much of each element is present in each stream in the WoodRoll® process. The models are verified with analysis results. Inorganic elements that affect the overall process and its equipment have been selected for modelling. The volume percent of H2, CO, CO2 and CH4 in the models agree well with the values obtained by Cortus Energy AB. This shows that the thermodynamic equilibrium calculations performed are reasonable. / De fossila bränslena beräknas vara förbrukade om 35 år för olja, 37 år för gas och 107 år för kol, räknat från år 2009. Användningen av fossila bränslen måste därför minskas genom övergång till förnybara resurser. Detta kommer i sin tur bidra till att motverka de fossila bränslenas negativa effekter på miljön, såsom den globala uppvärmningen. Termokemiska processer, som pyrolys och förgasning av biomassa, anses vara den mest effektiva tekniken för att omvandla biomassa till användbara energibärare. Cortus Energy AB är ett svenskt företag som har utvecklat en patenterad förgasningsteknik kallad WoodRoll ® för förgasning av biomassa. Aska i en termokemisk omvandlingsprocess kan ge upphov till korrosion, sintring, slagg samt förgiftning av katalysatorer vilket leder till operativa problem. Dessutom är tungmetaller såsom Zn, Pb och Cd miljömässigt relevanta. Dessa metaller bidrar till förorening av miljön, vilket i sin tur kan skada människor och ekosystemet via näringskedjan. De oönskade elementen bör därför identifieras för att minimera deras inverkan på den övergripande termokemiska processen och för att reducera utsläppet av dessa ämnen. Syftet med detta examensarbete, på uppdrag av Cortus Energy AB, var att undersöka möjliga nyckeltal som kan användas för att beskriva och förutse hur askan beter sig i deras patenterade WoodRoll® process. De nyckeltal som har undersökts teoretiskt är empiriskt utvecklade utifrån erfarenhet av förbränning av kol. Dessa nyckeltal används regelbundet av analysföretag på bränslen från biomassa trots att kunskapen om huruvida dessa faktiskt kan användas på biomassa är begränsad. För att säkerställa att användningen av dessa nyckeltal för aska från biomassa är korrekt måste de verifieras experimentellt i framtiden. Vidare görs en teoretisk undersökning för att studera vilka föreningar som möjligen kan bildas och i vilken fas detta sker. Denna undersökning visar att det inte finns en tydlig trend för hur de oorganiska elementen beter sig då olika studier har rapporterat motstridiga resultat. Vilka föreningar som bildas och i vilken fas i processen det i så fall sker beror på flera parametrar såsom temperatur, hastighet av uppvärmning, partikelstorlek, volatilitet, mängd samt interaktionen mellan de element som finns i biomassan. Arbetet avslutas med en massbalansmodell på utvalda oorganiska element för grenar och toppar, förkortat GROT, samt för bark. Detta kan bli ett verktyg för Cortus Energy AB för att identifiera ungefär hur mycket av varje element som finns i varje flöde WoodRoll®-processen. Modellen verifieras med analysresultat. Oorganiska element som påverkar processen och dess utrustning har valts för denna modell. Volymprocenten för H2, CO, CO2 and CH4 i modellen stämmer väl överens med de värden som Cortus Energy AB har erhållit. Detta visar att de termodynamiska jämviktsberäkningar är rimliga.

Cationic starch is a common wet-end additive in the paper industry which is mainly used to enhance retention and dry strength of the finished paper. At Smurfit Kappa Piteå, cationic starch is by far the most costly chemical used in the paper mill. It is therefore important that the added starch works efficiently, as poor adsorption of starch causes dissolved starch to circulate in the systems. This could cause slime deposits affecting the runnability of the paper machine and other equipment. In the planned production expansion at Smurfit Kappa Piteå during the nearest future, the demand on well-functioning wet-end starch will increase. Through mappings and laboratory studies, the purpose of the present project was to determine the efficiency of the current starch used in the paper mill and to identify any potential for improvements. A method to measure starch content in paper, pulp and white water was implemented to enable the above-mentioned activities to be carried out. As a tool for quality control of cooked starch, a microscopic method was implemented. The method was proven to be a simple and quick tool to verify whether the cooked starch was completely solubilized or not. Mappings at both paper machines were performed where adsorbed and dissolved starch content were analyzed according to the above-mentioned test method. The results showed the highest level of adsorption in the top ply system at PM2 while the base ply systems at both paper machines displayed lower levels. A significant difference of conductivity in pulps as well as furnishes is likely to explain the difference in adsorption efficiency between the systems. High levels of dissolved starch were observed in the top ply system at PM1 despite any use of cationic starch in this system. This is explained by dissolved starch in the white water that originates from other stock preparation systems is introduced via the shared dilution of pulp. A laboratory study was conducted to compare the adsorption of starches with different degree of substitution in pulp suspensions. The electrolyte concentration was adjusted to reflect the conditions in the base ply systems at PM1 and PM2.  Slightly higher adsorption was observed at higher levels of dosage for starch with a higher DS. Based on these values, the use of this product in the base ply systems at PM1 and PM2, could reduce the costs of starch through lowered dosages. A suggestion on how a rebuilding of the starch preparation system could be implemented has been made.

Syftet med detta arbete är att få en ökad förståelse om vilka parametrar som styr adhesion mellan NTTbältenoch pappersarket i NTT Advantage mjukpappersmaskin. Inga offentliga studier har gjortstidigare, därför var det även ett krav att hitta lämpliga metoder för att kunna utföra dessa analyser. Trelämpliga mätmetoder användes; Kruss MSA för ytenergi mätningar på bälte och pappersark, SZP-10 förundersökning av fiberladdning och filtratladdning, samt konduktometrisk titrering för bestämning avhalten sura grupper i fibrerna.De viktigaste faktorerna som styr adhesionen på NTT-bältet är vattenfilmen, malningsgraden ochandelen ”fines” i mälden. Malningsgraden och andelen fines ökar kontaktarean mellan fibrerna ochbältet, vilket resulterar i en ökad adhesion. En ökad malningsgrad, och låg CSF ger en ökad adhesionoch detta beror tillstörsta del på fibrernas förmåga att absorbera vatten. Fibrernas förmåga att absorberamer vatten ökar kapillärkraften mellan bältet och arket, vilket resulterar i en ökad adhesion.Vattenfilmen ändrar NTT-bältets ytenergi och påverkar den kapillära kraften som uppstår mellanvätskan och NTT-bältet. Detta beror främst på att man pressar ut vattnet som håller ihop pappersarketoch NTT-bältet, vilket resulterar i en minskad kapillärkraft.T61 interagerade med det hydrofila bältet G3 och ändrade dess hydrofila ytan till en hydrofob yta. Dettaindikerar att bältet är poröst och att kemikalierna sätter sig i porerna vilket ledde till förändrade ytegenskaper,även detta uppstår på grund av de kapillära krafter.