Examensarbeten för masterexamen // Master Theses
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Browsar Examensarbeten för masterexamen // Master Theses efter Program "Industrial ecology (MPTSE), MSc"
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- PostCorrelation between pollution levels and city design: How different building and vegetation scenarios affect air pollution at Fabriksgatan, Gothenburg — for different wind configurations and emission scenarios(2022) Emelie, Johansson; Chalmers tekniska högskola / Institutionen för mekanik och maritima vetenskaper; Ström, Henrik; Gustafsson, MalinAir pollution threat public health, the environment and objects of cultural value. It also affects the climate and is a big problem in many cities. It is therefore of interest to design cities in such a way that pollution levels are low. Pollution levels could be decreased via dispersion (when pollutants are diluted) and deposition (when pollutants deposit at surfaces). This report study how shape and size of buildings and different vegetation scenarios (one with just background vegetation; one with a sparse row of English oaks and background vegetation; one with a dense row of English oaks and background vegetation; and one with a green wall made of ivy and background vegetation) affect pollution levels of NO, NO2, O3, PM10 and PM2.5 for different wind configurations and emission scenarios for a specific area. The area is Fabriksgatan in Gothenburg and its surroundings. Two different street canyon widths are studied: one representing the width today and one wider, with room for a bike- and walkway and a row of trees. For this, the large eddy simulation (LES) model PALM, based on Fortran-code, is used. The main findings are that a wide street canyon enables more circulation and thus lower pollution levels. Small point houses open up the street canyon and such configurations have lower pollution levels than more confined street canyons. Both buildings and vegetation could be used to shield out emissions, but vegetation generally increases mean concentrations. This is believed to be due to an incomplete implementation of the effects of deposition in PALM. Thus, the effects of deposition must be studied in more detail before general advice on vegetation could be made.
- PostLife Cycle Assessment of solid oxide fuel cell systems for data centers A comparative study between three fuel alternatives: natural gas, biogas, and hydrogen(2022) Teixeira Taboada, Sabela; Chalmers tekniska högskola / Institutionen för mekanik och maritima vetenskaper; Brynolf, Selma; Brynolf, SelmaThe aim of this thesis was to evaluate the environmental performance of the solid oxide fuel cell (SOFC) BlueGEN BG-15 manufactured by Solid Power. To conduct this study, an attributional Life Cycle Assessment (LCA) was conducted to compare three fuel alternatives to be fed into the SOFC. This thesis was conducted in collaboration with RISE ICE and it is part of two European Union projects that deal with using fuel cells to provide reliable prime power for data centers. The research question to be answered was: “What is the environmental performance of a SOFC run with three different fuels: biogas from food waste, natural gas and hydrogen?”. To answer this question, the system was studied from cradle-to-grave using data provided from the manufacturers as well as literature. Biogas is locally produced from food waste in Sweden, natural gas comes from imports to Italy and the hydrogen is manufactured by electrolysis using electricity from the Italian energy grid. The different processes were modelled in the LCA software SimaPro. The database used was EcoInvent 3.7 and Environmental Footprint 3.0 was the impact method selected. The environmental impacts were evaluated for climate change, particulate matter, acidification, water scarcity, fossil fuels resource use and minerals and metals resources use. A contribution analysis to check the possesses with the highest environmental burden was done. Also, a sensitivity analysis was conducted to evaluate how the impacts change when renewable energy is used to produce the hydrogen. Results revealed that fuel production is responsible for most of the impacts. Only mineral and metals resource use is mostly affected by manufacturing the SOFC. Comparing the three fuel alternatives, hydrogen has by far the highest environmental impact. Biogas has the lowest climate change impact and fossil fuel resource use. For the remaining categories biogas and natural gas impact is similar. The environmental impact from hydrogen depends on the production pathways considered and could become an environmental competing alternative if renewable energy is used to produce it. This way, climate change impact would be reduced. However, other impacts linked to each energy source may arise. The thesis concluded with some mitigation measurements as well as possible areas of improvement for future research on this area.
- PostOffshore Oil and Gas Activities in Arctic areas(2013) Karlström Thylander, Emma; Chalmers tekniska högskola / Institutionen för sjöfart och marin teknik; Chalmers University of Technology / Department of Shipping and Marine TechnologyThe aim of this thesis report is to investigate how existing Best Available Techniques (BAT) for some key systems are affected by Arctic conditions and future expected requirements in Norway. The thesis report is focusing on assessing three systems with the most planned emissions to air and discharges to sea in oil and gas production facilities; Power and Heat generation, Flare system and Produced Water system. The thesis has been conducted in cooperation with Det Norske Veritas in Høvik, Norway during spring of 2013. This report consists of two parts; the first part involves the context and general settings on the Norwegian Continental shelf and the Arctic areas. This includes the oil and natural gas industry in Norway, identified environmental impacts and Arctic conditions. The existing regulation and guidelines on the Norwegian Continental shelf have been summarized and future requirements and guidelines for the Arctic areas have been considered and assessed to as large extent as possible. The second part consists of the findings of existing BAT and expected changes due to Arctic conditions for the key systems studied. By comparing the technical constraints and the environmental requirements the alternatives have been assessed if appropriate for Arctic conditions. The findings include expectations of stricter requirements for the Arctic areas in Norway at present and, depending on case, probably even stricter in the future. This will affect the existing BAT when applied with the expected requirements and the Arctic conditions. In general there are increased requirements when it comes to discharges to sea where the target of zero discharges is emphasized. Norway has both long term target to reduce emissions to air and to be carbon neutral in the future and to protect flora and fauna in the Arctic areas. What in general can be said from the findings are that there will probably be changes and effects on the existing BAT alternatives with Arctic conditions, mainly due to lower temperatures, remoteness and increased requirements regarding emissions and discharges to sea. There is also the question whether or not BAT is good enough for the Arctic? What is considered BAT is changing with time and perhaps there is a need for developing and implement techniques which currently are not presently regarded as BAT. There are large uncertainties when it comes to impacts and effects from offshore activities on the Arctic environment. What is considered BAT today might not be the same tomorrow and collaboration between different stakeholder such as governments, companies and nations are important for the future to be able to decrease the environmental impacts from oil and gas industry.
- PostTechno-economic and environmental assessment of electrification scenarios in waterborne public transport(2023) Cedrillo Ledesma, Andrea Celeste; Jutblad, Nils; Chalmers tekniska högskola / Institutionen för mekanik och maritima vetenskaper; Chalmers University of Technology / Department of Mechanics and Maritime Sciences; Brynolf, Selma; Malik Kanchiralla, Fayas; Styhre, LindaThe shipping industry currently stands for around 3% of the world’s greenhouse gas emissions (GHGs), and is predicted to increase its emissions significantly until 2050 unless mitigation efforts are made. For shorter routes and smaller vessels, electrifi cation has been identified as a promising method of decarbonisation. In this study, a techno-economic and environmental assessment framework was used in order to analyze the cost and environmental effects of electrifying public transport ferries op erating on the Göta Älv river in Gothenburg. Four different electrification scenarios were constructed based on information obtained from literature and interviews with relevant stakeholders. For these scenarios, the results suggest that three out of four would have lower costs than the baseline. The lowest cost of ownership was observed when optimizing the on-board battery capacity by deposition charging several times during the day, leading to around 8% lower costs than the baseline. As for the environ mental calculations, the results indicate a possible decrease in GHGs of about 77-90% of greenhouse gas emissions in the electrification scenarios compared to the baseline, with zero emissions of NOx , SO2 and particulate matter (PM) on a local level compared to present case. The scenarios showing the largest mitigation potential utilized wire less opportunity charging which allows for a significant decrease in on-board battery capacity compared to the baseline, thereby reducing upstream emissions from battery production. Overall, the study shows that there are positive environmental and cost ef fects of fully electrifying the Göta Älv ferries, which could act as inspiration for decision makers within waterborne public transport.