Examensarbeten för masterexamen // Master Theses
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- PostA CFD analysis of H2SO4 assisted alkali chloride sulfation in waste incineration(2019) Ahlberger, Vidar; Sundell, Sebastian; Chalmers tekniska högskola / Institutionen för kemi och kemiteknik; Andersson, Ronnie
- PostA CFD study of the urea supply, droplet breakup and mixing in a pipe upstream of a SCR catalyst(2013) Samuelsson, Emelie; Holmberg, Sara; Chalmers tekniska högskola / Institutionen för kemi- och bioteknik; Chalmers University of Technology / Department of Chemical and Biological Engineering
- PostA method to compartmentalize a high shear granulator(2014) Kvist, Patric; Chalmers tekniska högskola / Institutionen för kemi- och bioteknik; Chalmers University of Technology / Department of Chemical and Biological Engineering
- PostA modeling framework for resolving non-linear infrared absorbation in an FTIR cell(2015) Olsson, Axel; Chalmers tekniska högskola / Institutionen för kemi och kemiteknik; Chalmers University of Technology / Department of Chemistry and Chemical Engineering
- PostA study of three iron-based oxygen carriers in a Chemical Looping Combustion process with a Victorian brown coal(2014) Karlsson, Tove; Chalmers tekniska högskola / Institutionen för kemi- och bioteknik; Chalmers University of Technology / Department of Chemical and Biological Engineering
- PostAging model of a dissolving market pulp(2021) Eklund, Markus; Chalmers tekniska högskola / Institutionen för kemi och kemiteknik; Hasani, Merima; Palme, Anna; Fechter, Catharina
- PostAir assisted urea spray modeling, computational fluid dynamics simulation of urea spray using the Euler-Lagrangian(2013) Löfgren, Niklas; Chalmers tekniska högskola / Institutionen för kemi- och bioteknik; Chalmers University of Technology / Department of Chemical and Biological Engineering
- PostAlkylation of ethylene as self-alkylating agent over H-beta zeolite(2011) Chuacharoensiri, Pracha; Chalmers tekniska högskola / Institutionen för kemi- och bioteknik; Chalmers University of Technology / Department of Chemical and Biological Engineering
- PostAnalysing flashing in black liquor with active acoustic spectroscopy: Analysing flashing in black liquor with active acoustic spectroscopy(2021) Arvidsson, Emma; Lövström, Emma; Chalmers tekniska högskola / Institutionen för kemi och kemiteknik; Creaser, Derek; Winzell, Ann
- PostAnalysis of Fuel-Air Mixing in Jet in Crossflow(2021) Charoenchang, Wasinee; Chalmers tekniska högskola / Institutionen för kemi och kemiteknik; Andersson, Ronnie; Andersson, Ronnie; Lörstad, DanielWith the growth of energy demand nowadays, environmental concern of NOx emission from gas turbines has been increasing in attention. NOx emission can be lowered by decreasing the local maximum temperature which results from a good premixing of air and fuel. The mixing performance is affected by location of the fuel holes on the fuel pins which can be optimized using computational fluid dynamics. However, the computational mesh is known to be an important parameter which affect solution convergence and accuracy, thus it is significant to be optimized. The main goal was to develop the new mesh strategy and confirm grid independence to achieve higher accuracy with minimum number of cells. This thesis study applied a typical jet in crossflow (JIC) configuration to analyze the mixing of fuel and air in gas turbines related to fuel injection nozzles and Siemens PLM's STAR-CCM+ was chosen as a software. Previously used mesh strategies in SGT-750, SGT-800 and other projects in Siemens Energy AB were investigated in terms of grid independence properties and accuracy compared to the experimental data presented by F. Galeazzo et al. [1]. The results revealed that the mesh required improvement. Model dependence test including realizable k-epsilon, LES, lag EB k-epsilon and SST k-omega was performed. The choice of turbulence model was found to be important to achieve reliable predictions of the flow. Realizable k-epsilon and LES were the most suitable models for JIC simulation. To achieve good flow resolution, evaluated by turbulent kinetic energy and subgrid viscosity ratio, the cell sizes were properly identified by Kolmogorov and Taylor microscales. A successful mesh optimization approach was achieved by combining the best previously used mesh strategy and adaptive mesh refinement with respect to the concentration gradient. The optimized mesh exhibited high grid independency and the velocity and concentration fields agreed well with available experimental data. Therefore, the static optimized mesh is recommended to be used for future optimization of the fuel hole distribution in gas turbines.
- PostAnalysis of Multiphase Flow Centrifuge Decanter Separator Using CFD Simulations(2022) Khogali, Ahmed; Chalmers tekniska högskola / Institutionen för kemi och kemiteknik; Andersson, Ronnie; Bredberg, Jonas; Forero-Hernandez, HectorIn the industry, it is common to encounter multiphase flow in many different applications in the oil and gas, food production and waste treatment industries. The nature of multiphase flow is extremely complex and is continuously developing in terms of methods and tools to perform analysis. One device in the industry involving mutiphase flow is the centrifuge decanter separator for sewage water treatment with the aim of separating fluid and solids. The centrifuge decanter in this study is a separator from Alfa Laval (AL). This study aims at analyzing the decanter by using computational fluid dynamics (CFD) as a simulation tool in combination with the field of multiphase flow modeling to understand the decanter’s different components and complex functions at high rotational speeds. This makes the decanter a very demanding topic for this type of research. The analysis of the phenomena was done through systematic changes in parameters, strategies and models. The Euler- Euler and Mixture multiphase models were used to predict the distribution of water and solids throughout the domain within the decanter separator and determine how efficient the separation process is in terms of the amount of exiting solids. Operation parameters such as the differential speed of the decanter parts and boundary conditions within the domain were analyzed and results were presented.
- PostApplication of a mechanistic single droplet drying model to spray drying process at different scales(2023) Sjöberg, Karl; Chalmers tekniska högskola / Institutionen för kemi och kemiteknik; Chalmers University of Technology / Department of Chemistry and Chemical Engineering; Creaser, Derek; Nguyen, Duy
- PostAsh interactions with oxygen carriers Glödskal and LD-slag in biomass-CLC(2018) Eliasson, Felicia; Chalmers tekniska högskola / Institutionen för kemi och kemiteknik; Chalmers University of Technology / Department of Chemistry and Chemical EngineeringChemical-looping combustion (CLC) is a novel combustion technology where fuel is converted in the absence of air. The process is carried out in two fluidized bed reactors, one in which a metal oxide (oxygen carrier) is oxidized by air and one in which fuel is converted to combustion products through reaction with the oxidized oxygencarrier. Thecombustionproductsarethusinherentlyseparatedfromairand CO2 can be separated for carbon capture and storage without large energy penalties. Much of the current work with implementing conventional scale CLC aims at evaluatingtheperformanceandeconomicviabilityofdifferentoxygencarriers. CLC of biomass is of interest for sustainability reasons and evaluating if oxygen carriers are suitable for biomass-CLC includes ensuring that the material can perform well also in the presence of biomass ashes. Glödskal and LD-slag are two low cost steel industry by-products that have shown desirable fuel conversion properties in CLC, and their interactions with some common potassium ash components (KCl, K2CO3, K2SO4 and KH2PO4) in reducing atmosphere have been investigated in this study. Glödskal consists mainly of Fe and Fe oxides and traces of other metals and oil residuesfromtheprocess. ThemaincomponentsofLD-slagisCa-oxidesandoxides of Fe, Si, Mg and Mn. LD-slag also contains lower concentrations of Al, Ti and V. Utilizing low cost waste materials is beneficial both for economic and sustainable reasons. The materials have been mixed with potassium salt to obtain a mixture with 4wt% potassium content. The mixtures have been reduced in a glass quartz reactor for 8 hours in 850°C. The reduced samples have been analyzed in SEM with EDS.ThemixtureshavealsobeentestedinThermogravimetricanalysis. Itwasseen that all the salts except for KH2PO4 had positive effect on the porosity of Glödskal. K2CO3 increased the reduciton rate of Glödskal. KH2PO4 caused agglomeration of Glödskal which had a negative impact on the reactivity. The agglomeration is due to formation of a K-P-Fe component. Some accumulation of K was seen in both Glödskal and LD-slag after reduction in the presence of K2SO4. With K2CO3 and K2SO4 K accumulated in LD-slag together with vanadium. K2CO3 deactivated LDslag. KH2PO4 reacted with Ca in LD-slag and formed a K-P-Ca component which caused some agglomeration but didn’t affect the reduction rate.
- PostBiofuels from Biowaste via a Hybrid Process(2022) Dhakal, Prabin; Chalmers tekniska högskola / Institutionen för kemi och kemiteknik; Creaser, Derek; Achour, AbdenourOne of the main challenges the world is facing is global warming caused by greenhouse gas emissions, for which fossil fuels are responsible to a great extent. To combat this issue, there is a need to develop fuels from renewable sources. Food waste can be a potential source of such fuel. In this study, three different extraction techniques (soxhlet extraction, ultrasound -assisted extraction, and enzyme-assisted extraction) were conducted to characterize Renova’s food waste slurry. A new hybrid extraction method has been investigated to enhance the liquefaction, which successfully yielded the highest extracted liquid products. In addition, it investigates catalytic hydrotreatment of the extracted products was evaluated as a food waste valorization strategy to obtain biofuels. Compared to the three extraction methods, the liquefaction of food waste has been enhanced using the new hybrid extraction method while using ethanol as the solvent in wet conditions. The catalytic hydrotreatment of the extracted liquid and solid obtained from hybrid extraction method produced 87.9 wt% and 74.9 wt% of oil, 7.4 wt% and 13.4 wt% of solids and 7.1 wt% and 14.4 wt% of water respectively, with less than 0.5 wt% gas. Bio-oil from the extracted liquid product consists of 65.5 wt% of alkane-alkenes, 7.6 wt% of cyclic alkanes, 26.5 wt% of alcohol-ether and ketone compounds and less than 1 wt% of aromatics, naphthalenes, and alkylated phenols. Likewise, bio-oil from the extracted solid products consists of 75.6 wt% of alkane-alkenes, 3 wt% of cyclic alkanes, 15.3 wt% of alcohols and ethers 3.3 wt% of aromatics and naphthalenes and 2.8 wt% of alkylated phenols.
- PostBioprocessing of Lignin into Valuable Lipids A Techno-Economic Evaluation based on Modelling in ASPEN PLUS(2023) Utbult, Elin; Chalmers tekniska högskola / Institutionen för kemi och kemiteknik; Chalmers University of Technology / Department of Chemistry and Chemical Engineering; Olsson, Louise; Rådberg, Henrik
- PostCaprolactone from sugar platform chemicals: Conversion of 1,6-hexanediol to caprolactone(2019) Torre Poza, Andrea; Chalmers tekniska högskola / Institutionen för kemi och kemiteknik; Creaser, Derek
- PostCFD analysis of a novel rodent nose-only inhalation exposure chamber(2015) Razavi, Saman; Chalmers tekniska högskola / Institutionen för kemi och kemiteknik; Chalmers University of Technology / Department of Chemistry and Chemical Engineering
- PostCFD Modeling of Snow Contamination on Cars. Implementation of a Snow Adhesion Regime Map by User Defined Functions(2016) Enmark, Markus; Chalmers tekniska högskola / Institutionen för kemi och kemiteknik; Chalmers University of Technology / Department of Chemistry and Chemical Engineering
- PostCFD simulation of a secondary methane reformer(2013) Nilsson, Isaac; Andersson, Jimmy; Chalmers tekniska högskola / Institutionen för kemi- och bioteknik; Chalmers University of Technology / Department of Chemical and Biological Engineering
- PostCFD simulation of hydrodynamic loads on a floating vertical axis wind turbine(2019) Budesinsky, Marcus; Chalmers tekniska högskola / Institutionen för kemi och kemiteknik; Andersson, Ronnie