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  • 1.
    Acevedo Gomez, Yasna
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Applied Electrochemistry.
    Lindbergh, Göran
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Applied Electrochemistry.
    Lagergren, Carina
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Applied Electrochemistry.
    Reformate from biogas used as fuel in a PEM fuel cell2013In: EFC 2013 - Proceedings of the 5th European Fuel Cell Piero Lunghi Conference, 2013, p. 163-164Conference paper (Refereed)
    Abstract [en]

    The performance of a PEM fuel cell can be easily degraded by introducing impurities in the fuel gas. Since reformate of biogas from olive mill wastes will contain at least one third of carbon dioxide, its influence was studied on a PtRu catalyst. A clean reformate gas for the anode (67% H2 and 33% CO2) without any traces of other compounds was used and electrochemical measurements showed that the performance of the fuel cell was hardly affected. However, diluting the hydrogen with higher amounts of CO2 will reduce the performance remarkably.

  • 2.
    Alvarado Ávila, María Isabel
    et al.
    KTH, School of Engineering Sciences (SCI), Applied Physics.
    De Luca, Stefano
    KTH, School of Engineering Sciences (SCI), Applied Physics.
    Edlund, Ulrica
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Fei, Ye
    KTH, School of Engineering Sciences (SCI), Applied Physics.
    Dutta, Joydeep
    KTH, School of Engineering Sciences (SCI), Applied Physics.
    Cellulose as sacrificial agents for enhanced photoactivated hydrogen production2023In: Sustainable Energy & Fuels, E-ISSN 2398-4902, Vol. 7, no 8, p. 1981-1991Article in journal (Refereed)
    Abstract [en]

    The search for new energy sources together with the need to control greenhouse gas emissions has led to continued interest in low-emitting renewable energy technologies. In this context, water splitting for hydrogen production is a reasonable alternative to replace fossil fuels due to its high energy density producing only water during combustion. Cellulose is abundant in nature and as residuals from human activity, and therefore a natural, ecological, and carbon-neutral source for hydrogen production. In the present work, we propose a sustainable method for hydrogen production using sunlight and cellulose as sacrificial agents during the photocatalytic water splitting process. Platinum (Pt) catalyst activates hydrogen production, and parameters such as pH of the system, cellulose concentration, and Pt loading were studied. Using different biomasses, we found that the presence of hemicellulose and xyloglucan as part of the molecular composition considerably increased the H-2 production rate from 36 mu mol L-1 in one hour for rapeseed cellulose to 167.44 mu mol L-1 for acid-treated cellulose isolated from Ulva fenestrata algae. Carboxymethylation and TEMPO-oxidation of cellulosic biomass both led to more stable suspensions with higher rates of H-2 production close to 225 mu mol L-1, which was associated with their water solubility properties. The results suggest that cellulosic biomass can be an attractive alternative as a sacrificial agent for the photocatalytic splitting of water for H-2 production.

  • 3.
    Alvfors, Per
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    Arnell, Jenny
    IVL.
    Berglin, Niklas
    Innventia.
    Björnsson, Lovisa
    LU.
    Börjesson, Pål
    LU.
    Grahn, Maria
    Chalmers/SP.
    Harvey, Simon
    Chalmers.
    Hoffstedt, Christian
    Innventia.
    Holmgren, Kristina
    IVL.
    Jelse, Kristian
    IVL.
    Klintbom, Patrik
    Kusar, Henrik
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Chemical Technology.
    Lidén, Gunnar
    LU.
    Magnusson, Mimmi
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    Pettersson, Karin
    Chalmers.
    Rydberg, Tomas
    IVL.
    Sjöström, Krister
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Stålbrand, Henrik
    LU.
    Wallberg, Ola
    LU.
    Wetterlund, Elisabeth
    LiU.
    Zacchi, Guido
    LU.
    Öhrman, Olof
    ETC Piteå.
    Research and development challenges for Swedish biofuel actors – three illustrative examples: Improvement potential discussed in the context of Well-to-Tank analyses2010Report (Other academic)
    Abstract [en]

    Currently biofuels have strong political support, both in the EU and Sweden. The EU has, for example, set a target for the use of renewable fuels in the transportation sector stating that all EU member states should use 10% renewable fuels for transport by 2020. Fulfilling this ambition will lead to an enormous market for biofuels during the coming decade. To avoid increasing production of biofuels based on agriculture crops that require considerable use of arable area, focus is now to move towards more advanced second generation (2G) biofuels that can be produced from biomass feedstocks associated with a more efficient land use. Climate benefits and greenhouse gas (GHG) balances are aspects often discussed in conjunction with sustainability and biofuels. The total GHG emissions associated with production and usage of biofuels depend on the entire fuel production chain, mainly the agriculture or forestry feedstock systems and the manufacturing process. To compare different biofuel production pathways it is essential to conduct an environmental assessment using the well-to-tank (WTT) analysis methodology. In Sweden the conditions for biomass production are favourable and we have promising second generation biofuels technologies that are currently in the demonstration phase. In this study we have chosen to focus on cellulose based ethanol, methane from gasification of solid wood as well as DME from gasification of black liquor, with the purpose of identifying research and development potentials that may result in improvements in the WTT emission values. The main objective of this study is thus to identify research and development challenges for Swedish biofuel actors based on literature studies as well as discussions with the the researchers themselves. We have also discussed improvement potentials for the agriculture and forestry part of the WTT chain. The aim of this study is to, in the context of WTT analyses, (i) increase knowledge about the complexity of biofuel production, (ii) identify and discuss improvement potentials, regarding energy efficiency and GHG emissions, for three biofuel production cases, as well as (iii) identify and discuss improvement potentials regarding biomass supply, including agriculture/forestry. The scope of the study is limited to discussing the technologies, system aspects and climate impacts associated with the production stage. Aspects such as the influence on biodiversity and other environmental and social parameters fall beyond the scope of this study. We find that improvement potentials for emissions reductions within the agriculture/forestry part of the WTT chain include changing the use of diesel to low-CO2-emitting fuels, changing to more fuel-efficient tractors, more efficient cultivation and manufacture of fertilizers (commercial nitrogen fertilizer can be produced in plants which have nitrous oxide gas cleaning) as well as improved fertilization strategies (more precise nitrogen application during the cropping season). Furthermore, the cultivation of annual feedstock crops could be avoided on land rich in carbon, such as peat soils and new agriculture systems could be introduced that lower the demand for ploughing and harrowing. Other options for improving the WTT emission values includes introducing new types of crops, such as wheat with higher content of starch or willow with a higher content of cellulose. From the case study on lignocellulosic ethanol we find that 2G ethanol, with co-production of biogas, electricity, heat and/or wood pellet, has a promising role to play in the development of sustainable biofuel production systems. Depending on available raw materials, heat sinks, demand for biogas as vehicle fuel and existing 1G ethanol plants suitable for integration, 2G ethanol production systems may be designed differently to optimize the economic conditions and maximize profitability. However, the complexity connected to the development of the most optimal production systems require improved knowledge and involvement of several actors from different competence areas, such as chemical and biochemical engineering, process design and integration and energy and environmental systems analysis, which may be a potential barrier.

  • 4.
    Atat, Rachad
    et al.
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Radio Systems Laboratory (RS Lab).
    Yaacoub, E.
    Alouini, M. -S
    Abu-Dayya, A.
    Peer-to-peer content sharing techniques for energy efficiency in wireless networks with fast channel variations2013In: Green Networking and Communications: ICT for Sustainability, CRC Press , 2013, p. 3-28Chapter in book (Other academic)
    Abstract [en]

    According to the International Telecommunication Union, information and communication technology (ICT) was emitting 0.83 GtCO2e (gigatons of carbon dioxide equivalent), contributing to around 2%-2.5% of global greenhouse gas (GHG) emissions in 2007 [1]. With the continuous growth of ICT, especially in developing countries, the GHG emissions are expected to grow at double the rate over the next 10 years [1]. The Global e-Sustainability Initiative research is estimating a 72% increase in ICT energy usage from 2007 to 2020 with around 1.43 GtCO2e emissions in 2020 [1]. In addition, the telecommunications industry is witnessing an explosive increase in data traffic especially with the introduction of wireless modems and smart phones and with the presence of more than one billion wireless subscribers today. The data traffic volume is increasing by a factor of 10 every 5 years, leading to an increase of 16%-20% in energy consumption every 5 years [2]. For instance, in India, the mobile telecom industry is considered the fastest-growing sector with 584.3 million subscribers in 2010-2011 with an annual growth rate of 49.15%. It is estimated that the energy consumption of the Indian Mobile Telecom Industry was 163 PJ (petajoules) with 52.66 million tons emissions of carbon dioxide (CO2) in 2010-2011 [3]. A user who travels a distance of 25 km using public transport such as car or train can result in 1.22 kg of CO2 emissions, compared to 0.11 kg of CO2 emissions for 1 hour of video conferencing with two laptops [4]. A talk of 2 minutes per day on the phone can produce 47 kg CO2e (equivalent) per year, with a total of 125 million tons of CO2e produced by mobile phones in 1 year [5]. 

  • 5. Campisi, T.
    et al.
    Tesoriere, G.
    Skoufas, Anastasios
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Transport planning.
    Zeglis, D.
    Andronis, C.
    Basbas, S.
    Perceived Pedestrian Level of Service: The case of Thessaloniki, Greece2022In: Transportation Research Procedia, Elsevier BV , 2022, p. 124-131Conference paper (Refereed)
    Abstract [en]

    Level of Service (LOS) is one of the most crucial components for the assessment of pedestrian facilities by mainly concerning the effective width as well as pedestrians’ flows. However, current research reveals that qualitative characteristics can also contribute to LOS estimation as perceived by pedestrians. Specifically, socio-demographic characteristics (i.e., age, gender) as well as characteristics related with perceived comfort and safety can be related with perceived LOS. A Revealed Preference (RP) face to face questionnaire-based survey (including 301 interviewees) was realized during October 2019 at a central pedestrian facility in the city of Thessaloniki, Greece. RP questionnaire survey assisted in gaining valuable knowledge concerning the factors that mainly affect pedestrians’ perceived LOS across the pedestrian facility. The examined pedestrian facility is one of the most important in Thessaloniki since it facilitates high pedestrian flows within the city center daily. The present survey considered pedestrians’ general mobility characteristics such as walking frequency along the facility and trip purpose. Additionally, the evaluation of the greater facility’ area in terms of land use attractiveness, comfort, personal and road safety, public transport, parking conditions and traffic delays, accessibility, pedestrians and bicycles were concerned as well. Ordinal regression was the main tool for the development of the ordinal regression model, and therefore, for the conclusions’ drawing of the present research. The findings regarding perceived LOS can pave the way towards the design of sustainable policy concerning pedestrian facilities as well as the encouragement of active transport in urban areas.

  • 6.
    Chen, Binbin
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Pyrolytic biochar stability assessed by chemical accelerating aging method2020Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Now that the EU and Sweden have adopted a new climate policy framework to regulate net carbon emission. A new concept, negative CO2 emission, has been considered to neutralize the CO2 generated from necessary consumption of fossil fuel. Biochar, as a pyrolytic product from biomass, can store carbon in a relatively stable way. Therefore, it is one of the most promising and outstanding tools for carbon sink.

    Biochar stability, defined as the ratio of remaining carbon in biochar after 100 years, is the most crucial factor when using biochar for carbon storage. So far, various approaches have been proposed to measure and predict biochar stability, such as elemental analysis, proximate analysis, accelerating aging methods. Each method has its pros and cons. The reliability of these methods still needs to be verified. In this project, the chemical accelerating aging method has been selected for assessing biochar stability, because this method captures both chemical and physical properties of biochar. Besides, the gas, liquid, and solid products generalized during the chemical treatment are collected and analyzed separately in order to study the oxidation mechanism.

    Biochar in this project is produced from miscanthus and seaweed at various pyrolysis temperature. It is found that biochar stability can be increased by enhancing pyrolysis temperature, and miscanthus biochar is more sensitive to pyrolysis temperature within the pyrolysis temperature range of 350-600℃. The highest biochar stability (73%) has been achieved with miscanthus-derived biochar produced at 550 ℃, which demonstrates high potential as carbon sequestration tool.

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  • 7.
    Cuvilas, Carlos Alberto
    et al.
    Swedish University for Agricultural Sciences (SLU), Department of Energy and Technology, Uppsala, Sweden .
    Jirjis, R.
    Swedish University for Agricultural Sciences (SLU), Department of Energy and Technology, Sweden .
    Lucas, C.
    Energy situation in Mozambique: A review2010In: Renewable & sustainable energy reviews, ISSN 1364-0321, E-ISSN 1879-0690, Vol. 14, no 7, p. 2139-2146Article, review/survey (Refereed)
    Abstract [en]

    The need to increase energy security and promote development, especially in rural areas has forced many developing countries in southern Africa, like Mozambique to take several actions toward development of several infrastructures and legislations for production and use of liquid biofuels. The main objective of this study is to present the energy situation in Mozambique and assess the potential for energy generation from widely available renewable sources including residues from agricultural crops and forest industry. The country is endowed with great potential for biofuels, solar, hydro and wind energy production. The energy production today is, however, far from fulfilling energy needs of the country, and the majority of people are still not benefiting from these resources. The potential of total residues from agricultural sector and forest industry is estimated to be around 128 PJ. This amount of energy covers almost half of the combined production of charcoal and firewood which amounted to approximately 298 PJ in 2006. However, such amount of energy resources is wasted and is not visible on national energy statistics.

  • 8.
    Dias Batista, Edgard
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Energy and Climate Studies, ECS.
    Etanolens hållbarhet – en litteraturöversikt2012Report (Other (popular science, discussion, etc.))
    Abstract [sv]

    Etanol är ett omdebatterat bränsle bland miljödebattörer och politiker, men även bland forskare. I denna studie har 192 vetenskapligt granskade artiklar om etanol studerats och slutsatserna kvantifierats. Slutsatserna har delats in i sex frågeområden, utöver de övergripande slutsatser om etanol som hållbart drivmedel. Litteraturstudien visar att en majoritet av artiklarna har slutsatser som är positiva till att använda etanol som biodrivmedel. Sammanställningen över artiklarnas övergripande slutsatser, som är den viktigaste frågan i studien, visar att 65 procent av slutsatserna är positiva eller mycket positiva, 10 procent av artiklarna är neutrala eller ofullständiga, medan summan av de negativa och helt negativa slutsatserna är 25 procent. Inom samtliga sex områden är andelen positiva slutsatser högre än de negativa. Frågan där fördelningen är jämnast gäller den om etanolens inverkan på livsmedelspriser och livsmedelsproduktion där 54 procent av artiklarna var positiva eller mycket positiva till använda etanol som drivmedel. 43 procent var negativa eller mycket negativa.

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    Etanol - Edgard
  • 9.
    Enefalk, Tommy
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Industrial Ecology.
    Ersöz, Timur
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Industrial Ecology.
    Optimal rening av biogas för småskalig produktion och användning: En studie om energioptimering av biogasanläggningar2016Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Biogas is a renewable fuel, and the demand for this particular fuel type is increasing around the world. In order to use biogas as a fuel for vehicles it must first be upgraded from its raw state. By separation of carbon dioxide and other impurities, the methane content in the raw biogas is increased so that the biogas can be used in engines. Several methods of purification exist, but this report mainly focuses on water scrubbing. This thesis aims to investigate the optimal methane content in biogas with respect to net energy and the lifespan of the engines that are being fueled with biogas. The focus of the report is on the purification process in biogas production for small to medium sized farms. The thesis is conducted by putting up an energy balance formula for the components in the biogas production system. This formula was used for creating a mathematical model of the system, and the calculations were made with the computer programme Matlab. The optimal methane content in the biogas was found to be around 80 % (78 – 83 %), which is less than the lower limit (85 %) that is recommended by other sources. The purification facility’s own energy demand corresponds to 2,5 – 8,6 % of the energy content in the biogas, depending on whether high pressure compression is used or not. These results are highly consistent with previous research. The methane content of the biogas does not reduce the lifespan of the engines notably, but there is a risk of ignition failures which could lead to damages in the catalyzer. Since the optimal methane content is lower than 85 %, it would be appropriate to test the biogas in order to analyze if it is suitable to be used as a fuel. The results are heavily influenced by the engine efficiency, which is also a relevant subject for future work. 

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  • 10.
    Engquist, Ellen
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Industrial Biotechnology.
    Insulated Metabolic Exchange for Sustainable Agriculture and Biotechnology2023Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Between 1960 and today, the world population has doubled while food production has tripled. This has been made through chemical fertilisers being introduced in the middle of the 20th century. From 1965, the usage of nitrogen fertilisers has increased by sixfold. Nitrogen fertilisers improve crop profitability and yield but have large carbon dioxide emissions as well as cause eutrophication. Thus, there is a demand for an alternative. One alternative would be to engineer the rhizosphere. To investigate whether this is possible, a model system for insulated metabolic exchange will be created. The model system will have a nitrogen-fixating bacteria that will fixate atmospheric nitrogen and produce a nitrogen compound to a carbon-fixating bacteria, that will act as a plant in the model system. The carbon-fixating bacteria will fixate carbon dioxide from the atmosphere and produce a carbon source for the nitrogen-fixating bacteria to utilise. In this study, different productions of different nitrogen compounds in Escherichia coli and Anabaena sp. have been investigated. Four different plasmids have been constructed for the production of alanine, guanine and allantoin, respectively. The strains containing the plasmids all grew better than the control cultures, however, they have not been analysed for producing the metabolites due to time constraints. 

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  • 11.
    Engvall, Klas
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Chemical Technology.
    Liliedahl, Truls
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Chemical Technology.
    Dahlquist, E.
    Biomass and black liquor gasification2013In: Technologies for Converting Biomass to Useful Energy: Combustion, Gasification, Pyrolysis, Torrefaction and Fermentation, CRC Press , 2013, p. 175-216Chapter in book (Other academic)
    Abstract [en]

    Modern society is profoundly dependent on fossil feed stocks to produce multiple products, such as transportation fuels, fine chemicals, pharmaceuticals, detergents, synthetic fibers, plastics, fertilizers, lubricants, solvents, waxes, etc., as well as heat and power (Demirbas, 2006). The fossil resources are not endless. Their price is increasing continuously due to increasing scarcity, and not regarded as sustainable from an environmental point of view (Kamm, 2006). A versatile resource, especially in terms of producing carbon-based products, to replace fossil feedstocks is biomass (Vlachos, 2010) or other sources originating form biomass, such as black liquor (BL). Conversion of biomass to other products can be performed either by biochemical or thermochemical processes. In the case of large-scale production of, for example, carbon-based products, thermo-chemical conversion is considered more efficient compared to biochemical processes (Zhang, 2010). Techniques for thermo-chemical conversion can be divided into pyrolysis, gasification, combustion and liquefaction. Among these techniques, gasification is a versatile platform for production of multiple products, as illustrated in Figure 6.1. 

  • 12.
    Evangelopoulos, Panagiotis
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Kantarelis, Efthymios
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Yang, Weihong
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Experimental Investigation of Pyrolysis of Printed Circuit Boards for Energy and Materials Recovery under Nitrogen and Steam Atmosphere2017In: 8th International Conference on Applied Energy, ICAE 2016; Beijing; China; 8 October 2016 through 11 October 2016, Elsevier, 2017, Vol. 105, p. 986-991Conference paper (Refereed)
    Abstract [en]

    Printed circuit boards (PCB) are one of the most challenging fractions of e-waste in terms of material recycling and energy recovery. In this study, pyrolysis of PCBs in inert and steam atmosphere has been investigated as a valuable alternative for energy recovery of the organic fraction with simultaneous recycling of metals. The decomposition of two different PCB fractions has been investigated by means of thermogravimetric analysis (TGA) and lab scale pyrolysis experiments in steam and nitrogen atmospheres. The composition of the gas obtained from the pyrolysis experiments was strongly influenced by the reactive atmosphere. The characterization of the solid residue by X-ray Powder Diffraction (XRD) and scanning electron microscopy (SEM) showed high influence of steam to the migration of the antimony in the produced vapors.

  • 13.
    Fu, Shanfei
    et al.
    Jiangnan Univ, Sch Environm & Civil Engn, Wuxi, Jiangsu, Peoples R China..
    Angelidaki, Irini
    Tech Univ Denmark, Dept Chem & Biochem Engn, Lyngby, Denmark..
    Cetecioglu, Zeynep
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Resource recovery.
    Kong, Qiang
    Shandong Normal Univ, Coll Geog & Environm, Jinan, Peoples R China..
    Zheng, Yi
    Kansas State Univ, Dept Grain Sci & Ind, Manhattan, KS 66506 USA..
    Tsapekos, Panagiotis
    Tech Univ Denmark, Dept Chem & Biochem Engn, Lyngby, Denmark..
    Editorial: Biological Strategies to Enhance the Anaerobic Digestion Performance: Fundamentals and Process Development2021In: Frontiers in Microbiology, E-ISSN 1664-302X, Vol. 12, article id 762875Article in journal (Other academic)
  • 14.
    Ge, Yaxin
    et al.
    Department of Chemistry and Molecular Biology, Atmospheric Science, University of Gothenburg, SE-412 96 Gothenburg, Sweden.
    Ding, Saiman
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Process Technology.
    Zhang, Wennan
    Department of Chemical Engineering, Mid Sweden University, SE-85170 Sundsvall, Sweden.
    Kong, Xiangrui
    Department of Chemistry and Molecular Biology, Atmospheric Science, University of Gothenburg, SE-412 96 Gothenburg, Sweden.
    Kantarelis, Efthymios
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Process Technology.
    Engvall, Klas
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Process Technology.
    Pettersson, Jan B.C.
    Department of Chemistry and Molecular Biology, Atmospheric Science, University of Gothenburg, SE-412 96 Gothenburg, Sweden.
    Impacts of fresh bed materials on alkali release and fuel conversion rate during wood pyrolysis and char gasification2023In: Fuel, ISSN 0016-2361, E-ISSN 1873-7153, Vol. 353, article id 129161Article in journal (Refereed)
    Abstract [en]

    Bed materials provide efficient heat transfer and catalytic function in the thermochemical conversion of biomass, but their interactions with the fuel remain incompletely understood. In this study, the effects of bed materials on alkali release and fuel conversion during wood pyrolysis and CO2 gasification are investigated by online alkali detection combined with thermogravimetric analysis. The investigated bed materials include silica, sea sand, alumina and the natural ores olivine, ilmenite and dolomite. Only dolomite has a significant effect on fuel mass loss and alkali release during wood pyrolysis, while all bed materials influence char reactivity and alkali release during gasification. Sea sand, alumina and dolomite enhance the char gasification during the whole or most of the gasification process, which is related to alkali migration from the bed materials. All bed materials affect char reactivity and alkali release when the conversion approaches completion, and small amounts of some bed materials reduce the alkali release by an order of magnitude. The findings can be understood based on the chemical composition of the different materials. Silicon-rich materials reduce the levels of catalytically active alkali by formation of stable alkali silicates, and a similar explanation applies for ilmenite that captures alkali efficiently. Magnesium and calcium in contrast promote alkali release through their influence on alkali silicate chemistry. Analysis of char surfaces using scanning electron microscopy with energy dispersive spectroscopy indicates that low amounts of several elements are transferred from the bed material to the char where they may be directly involved in the char conversion process. The transferred elements are specific for each bed material and relates to their chemical composition. Mechanisms for material exchange between bed material and char are discussed.

  • 15.
    Giagkalos, Panagiotis
    KTH, School of Industrial Engineering and Management (ITM), Industrial Ecology.
    Scenario Development for the City of Stockholm Towards a Fossil Fuel Free City by 20502012Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The City of Stockholm’s energy and climate goals are analyzed and projected in several scenarios. Using the year 2015 as the baseline year, a database covering the energy performance and fuel use within the City is created. This starting point is used to project the performance of the City until the year 2050. The projection is made with the use of scenarios and the simulation software LEAP by formulating scenarios that combine ongoing, planned and conceivable measures. All these scenarios aim to the reduction of emissions with the long term aim to set the City of Stockholm a fossil fuel free city by 2050. Various paths can be followed towards that goal and these are analyzed and classified based on cost and applicability. According to the simulation of scenarios, the immediate action and the long-term planning are shown to play an essential role in achieving the City’s goals. In addition, the significance of policy, the behavioral aspect and the continuous gradual development are found to be three basic pillars towards the target that the City has set. Specifically, the City should focus on energy efficiency in both generation and utilization. Available technology can help to this direction at an affordable cost and with remarkable potential. However, in order to achieve the target of an entirely fossil fuel free city by the year 2050, the City of Stockholm needs to support a shift of transportation modes towards public transport. Currently, the transportation sector has a low share of clean fuels and is likely going to be the most challenging sector to affect. Among the challenges in the transportation sector comes the fact that there is always a given risk when trying to introduce a new dominant fuel, based on assumptions of future car fleets and volatility of markets. Biofuels may for instance lead to a shortage in the market with higher biofuel and food prices as a result while changing the entire vehicle fleet takes 20 years on average. The best possible scenario does demonstrate one possible path toward a fossil fuel free City of Stockholm 2050 by taking a number of aggressive actions. This does not account for possible new technologies nor changes in the economy at large.

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  • 16.
    Gitau, James K.
    et al.
    Univ Nairobi, Wangari Maathai Inst Peace & Environm Studies, POB 2905-0065, Nairobi, Kenya.;World Agroforestry Ctr ICRAF, POB 30677-00100, Nairobi, Kenya..
    Sundberg, Cecilia
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Resources, Energy and Infrastructure.
    Mendum, Ruth
    Penn State Univ, Off Int Programs, Coll Agr Sci, 106 Agr Adm Bldg, University Pk, PA 16802 USA..
    Mutune, Jane
    Univ Nairobi, Wangari Maathai Inst Peace & Environm Studies, POB 2905-0065, Nairobi, Kenya..
    Njenga, Mary
    Univ Nairobi, Wangari Maathai Inst Peace & Environm Studies, POB 2905-0065, Nairobi, Kenya.;World Agroforestry Ctr ICRAF, POB 30677-00100, Nairobi, Kenya..
    Use of Biochar-Producing Gasifier Cookstove Improves Energy Use Efficiency and Indoor Air Quality in Rural Households2019In: Energies, E-ISSN 1996-1073, Vol. 12, no 22, article id 4285Article in journal (Refereed)
    Abstract [en]

    Biomass fuels dominate the household energy mix in sub-Saharan Africa. Much of it is used inefficiently in poorly ventilated kitchens resulting in indoor air pollution and consumption of large amounts of wood fuel. Micro-gasification cookstoves can improve fuel use efficiency and reduce indoor air pollution while producing char as a by-product. This study monitored real-time concentrations of carbon monoxide (CO), carbon dioxide (CO2) and fine particulate matter (PM2.5), and amount of firewood used when households were cooking dinner. Twenty-five households used the gasifier cookstove to cook and five repeated the same test with three-stone open fire on a different date. With the gasifier, the average corresponding dinner time CO, CO2, and PM2.5 concentrations were reduced by 57%, 41%, and 79% respectively compared to three-stone open fire. The gasifier had average biomass-to-char conversion efficiency of 16.6%. If the produced char is used as fuel, households could save 32% of fuel compared to use of three-stone open fire and 18% when char is used as biochar, for instance. Adoption of the gasifier can help to reduce the need for firewood collection, hence reducing impacts on the environment while saving on the amount of time and money spent on cooking fuel.

  • 17.
    Harahap, Fumi
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Energy and Climate Studies, ECS.
    Silveira, Semida
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Energy and Climate Studies, ECS.
    Khatiwada, Dilip
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Energy and Climate Studies, ECS.
    Integrated biorefinery vs. stand alone biodieselproduction in Indonesia – an economic analysis2017In: European Biomass Conference and Exhibition Proceedings, 2017Conference paper (Other academic)
    Abstract [en]

    Biofuel policy instruments have largely steered the expansion of the biodiesel industry in Indonesia,promoting investments and creating fuel markets. Despite the growth, biodiesel use has not yet reached thedeployment targets set by the government. Low profitability and dysfunctional markets forces some plants to operatefar below the installed production capacity, which results in a deficit of biodiesel supply for domestic markets. At thesame time, biodiesel is being exported. The current production configuration of biodiesel in a standalone biodieselplant is perceived to be unprofitable without government subsidy. Therefore, we propose a comparative economicanalysis for biodiesel production in Indonesia using two configurations: the standalone production system typicallyused at present, and an integrated bio-refinery plant. The results show that the biodiesel production cost in thebiorefinery is 13% higher compared to the production cost in a standalone plant. However, due to higher revenuesgenerated in the biorefinery (16% higher than standalone system), biorefinery concept offers more profits to theindustry. Under current economic conditions, the integrated biorefinery concept brings advantages throughimprovement of efficiency in the biodiesel production system and higher production of other valuable products suchas electricity.

  • 18.
    Hassanzadeh, Masoumeh
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Wood Chemistry and Pulp Technology.
    Li, Jiebing
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    TUNICATES FOR BIO MATERIALS PRODUCTION: EFFECTS OF DIFFERENT FACTORS ON CELLULOSE AND PROTEIN COMPOSITION2014In: PAPERS OF THE 22ND EUROPEAN BIOMASS CONFERENCE: SETTING THE COURSE FOR A BIOBASED ECONOMY, 2014, p. 1116-1123Conference paper (Refereed)
    Abstract [en]

    Tunicates, a group of marine animals, is gaining a lot of interests in case of medical, food market, water pollution, cellulosic nanomaterial, and biofuel production issues due to their consisting of chemical compounds such as cellulose, amino-sugars, and proteins or protein-polysaccharide complexes. In this work, two dominant species of Scandinavian tunicates have been investigated by extraction and characterization of their cellulose, and amino acids. Samples in different sizes, ages, place of growing (Distance to ocean's surface), and different chemical pretreatment, have been evaluated in their compositions to see the best conditions for extraction of cellulose and protein. For pure cellulose and bioethanol productions, the samples growing near to the ocean surface at the best harvesting time (after completion of metamorphosis), recommended to be explored. The highest amount of protein in tunicate body has been found in the internal organs with a total amino acid content of around 52 %. In addition, the larger and elder the sample is, the higher amount of protein it contains. Hence, for feed supplementing point of view, the internal organs of tunicates with higher size and age are favored to be considered. Eventually, a combination of both H3PO4 and Ba (OH)(2) might lead to a significantly high cellulose percentage (66.5%) and a high protein removal percentage (protein content of 6%) when aiming at cellulose extraction.

  • 19.
    Hellmér, Elin
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Industrial Ecology.
    CLIMATE PERFORMANCE OF BIOFUELS: PRODUCED FROM FOREST RESIDUE HARVESTED IN SWEDEN2016Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Biofuels produced from forest residues are much discussed in a Swedish context, among other things due to concerns for climate change. However, the undertaking of climate performance calculations is not an exact science. To examine whether climate concerns may be met by biofuels produced from forest residues, a literature review was carried out, analysing studies across methodologies.

    The scope for the literature review was limited to climate performance calculations for biofuels produced from forest residues harvested in Sweden. Five articles have been chosen for presentation, whereof one was carried out according to ISO 14040:2006 methodology, two according to climate performance calculations as stipulated by RED, two according to cumulative radiative forcing (CRF) and one according to a bottom up model using data from demo plants in Sweden (one study covers both ISO and RED methodology). All five studies presented in this paper suggest that climate performance of biofuels produced from forest residue (harvested in Sweden) show significantly better climate performance than fossil fuels.

    The local, environmental effects as well as future potential for harvesting of forest residue were also explored. A synthesis report on local, environmental effects suggests that the local, environmental effects are small. Furthermore, it is concludes that the effects on SOC are minor. Lastly, it is suggested that there is potential of increased harvesting of forest residue in Sweden in the magnitude of 30 TWh. 

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  • 20.
    Henrique, Pacini
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Energy and Climate Studies, ECS.
    Silveira, Semida
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Energy and Climate Studies, ECS.
    Consumer choice between Ethanol and Gasoline: Lessons from the Cases of Brazil and Sweden2010In: Conference proceedings 3rd International Scientific Conference on “Energy systems with IT” / [ed] Erik Dahlquist, Jenny Palm, 2010Conference paper (Refereed)
  • 21.
    Johnson, Francis X
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Energy and Climate Studies, ECS.
    Bioenergy and the Sustainability Transition: from local resource to global commodity2007Conference paper (Refereed)
  • 22.
    Johnson, Francis X.
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Energy and Climate Studies, ECS.
    Seebaluck, Vikram
    Bioenergy for Sustainable Development and International Competitiveness: The Role of Sugar Cane in Africa2012Collection (editor) (Other academic)
    Abstract [en]

    Growing concerns about the impacts of climate change and dependence on fossil fuels have intensified interest in bioenergy from sugar cane and other crops, highlighting important links between energy, environment and development goals. Southern and Eastern Africa are characterized by severe poverty; the possibility to exploit a renewable energy resource offers valuable avenues for sustainable development and could support a more dynamic and competitive economy. This book describes how the bioenergy expansion will improve rural livelihoods, reduce costly energy imports, reduce GHG emissions, and offer new development paths.

    Drawing on international experience, particularly from Brazil and India, it is shown that harnessing this potential will require significant increases in investment, technology transfer, and international cooperation. Because of its high efficiency, the authors argue that sugar cane should be viewed as a global resource for sustainable development and should command much greater focus and concerted policy action. Through an analysis of the agronomy, land suitability and industrial processing of sugar cane and its co-products, along with an assessment of the energy, economic and environmental implications, this volume demonstrates that sugar cane offers a competitive and environmentally beneficial resource for Africa's economic development and energy security.

    With fourty-four authors representing thirty organisations in sixteen countries, the book offers a truly international and interdisciplinary perspective by combining technical and economic principles with social, political and environmental assessment and policy analysis.

  • 23.
    Kantarelis, Efthymios
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Yang, Weihong
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Blasiak, Włodzimierz
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Biomass pyrolysis for energy and fuel production2013In: Technologies for Converting Biomass to Useful Energy: Combustion, Gasification, Pyrolysis, Torrefaction and Fermentation, CRC Press , 2013, p. 245-278Chapter in book (Other academic)
    Abstract [en]

    Pyrolysis is the thermochemical decomposition of organic matter in the absence of oxygen and produces a wide range of useful products. The word is coined from the Greek-derived elements pyr "ρ-fire” and lysis "λUsσς-breakdown/separation” emphasizing the disintegration of matter due to heat. It is a standalone process or one of several reaction steps in gasification and combustion processes1 and is considered as the basic thermochemical process to produce valuable fuels and energy from biomass. Pyrolysis is also known as thermolysis, thermal cracking, dry distillation, destructive distillation, etc.; however, there are differences in those terms. During pyrolysis, complex macromolecules of biomass break down into relatively smaller molecules producing 3 major products which can be classified as follows: •a solid residue (which mainly consists of carbon and ash) known as char•gases (mainly CO, CO2, CH4, H2 and other light hydrocarbons)•Vapors/liquids known as bio-oil or bio-crude (mainly oxygenates, aromatics, water, products of low degree of polymerization, tars, etc.)

  • 24.
    Karlsson, Sara
    KTH, School of Industrial Engineering and Management (ITM), Industrial Ecology.
    Sustainable use of Baltic Sea natural resources based on ecological engineering and biogas production: System analysis and case study Trelleborg2009Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Eutrophication is one of the most serious environmental problems in the Baltic Sea due to factors such as nutrient discharges from different sources and long residence time. Eutrophication gives rise to increased primary production, often followed by oxygen depletion and disruption of important ecosystems. An action plan has been created by the Helsinki Commission (HELCOM) in order to achieve good ecological status of the Baltic Sea in the year of 2021. According to the action plan, 21 000 tonnes of nitrogen and 290 tonnes of phosphorus shall be decreased of the annual discharge from Sweden.

    The aim of methods within ecological engineering is to solve environmental problems, and the applications ranging from the harvesting of existing ecosystems to the construction of new ecosystems. This study evaluates if harvest of algae, reed, and mussels can help meeting the goals of the action plan considerably, in accordance with areas and biomass amounts that need to be harvested, and to assess the efficiency of the three biomasses with regards to nutrient reduction. The potential of harvested biomasses as substrates in biogas production and as fertilizers is investigated, and how much fossil CO2 that can be saved from being released to the atmosphere if net energy benefits, calculated from energy budgets in the biogas process, replaces fossil fuels.

    Life cycle inventories which extend from the harvest (i.e. from the Baltic coast of Sweden) to the production of biogas have been made in order to investigate the biogas potential of algal, reed, and mussel biomass. Suitability of the three biomasses as fertilizers has been assessed through comparison between nutrient sufficiency of crops and nutrient contents of the three biomasses (i.e. based on quotients of nitrogen).

    The quantity of biomass in the areas that can be harvested can help meeting the goals of the action plan drawn up by HELCOM, and mussels show to be most efficient with regards to nutrient reduction efficiency. Reed has the highest net energy benefit followed by algae, and both biomasses show potential of further investigation as substrates in the biogas production process. Mussels have low net energy benefit and thus are not a suitable substrate in biogas production. The three biomasses are suitable as fertilizers with respect to contents of nitrogen but the content of phosphorus occurs under the sufficiency levels for the crops (i.e. peas, grain, and sugar beets). For algae and reed, the potassium contents occur above the sufficiency level for peas and grain but under the level for sugar beets, mussels contain lower levels of potassium than the need of the investigated crops.

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  • 25.
    Khudur, Ivan
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Aluminium alloys ability to catalyse the oxidation of biodiesel: Development of a procedure to test alloys2017Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Biodiesel is a renewable and biodegradable fuel that has the possibility to replace conventional diesel fuel and reduce the environmental pollution. Despite its environmental benefits, it has been shown to cause damage to the vehicle engines, due to its oxidative properties. Different metals, such as copper, zinc and aluminium are present in the vehicle fuel system and have been shown to catalyse the oxidation of biodiesel. Several studies have been performed to investigate the interaction between these metals and fuel. However, some reports concluded contradicting results when it comes to the oxidation of biodiesel in contact with aluminium alloys. This project aimed therefore to investigate and create a simple method for comparing the catalytic effect on oxidation for metals, and use this method to evaluate the degradation rate of biodiesel in contact with aluminium alloys. Different heating methods and coating materials were tested using the biodiesel RME to develop the testing procedure. When a test procedure was established, three filter houses made from cast aluminium alloy and three aluminium ingots with different amount of copper were immersed in RME and the stability was evaluated. The results showed that using an oven at 80 °C to investigate the stability provided the most repeatable results, and the spray paint Auto K billack spray Universal appeared to be compatible to use with RME. The inner untreated surface of the fuel filter houses did not seem to increase the oxidation rate of biodiesel. Aluminium alloys with higher copper content degraded RME more than aluminium alloys with little/no copper, if the surface had been treated mechanically, but not to a large extent. This concludes that aluminium alloys may reduce the stability of biodiesel if it contains much copper and if the surface of the alloy has been treated. However, the detected reduction on oxidation stability could depend on other factors, and therefore it is recommended to conduct further experiments on test the aluminium alloys.

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    Aluminium alloys ability to catalyse the oxidation of biodiesel: Development of a procedure to test alloys
  • 26.
    Khudur, Ivan
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Aluminium alloys ability to catalyse the oxidation of biodiesel: Development of a procedure to test alloys2017Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Biodiesel is a renewable and biodegradable fuel that has the possibility to replace conventional diesel fuel and reduce the environmental pollution. Despite its environmental benefits, it has been shown to cause damage to the vehicle engines, due to its oxidative properties. Different metals, such as copper, zinc and aluminium are present in the vehicle fuel system and have been shown to catalyse the oxidation of biodiesel. Several studies have been performed to investigate the interaction between these metals and fuel. However, some reports concluded contradicting results when it comes to the oxidation of biodiesel in contact with aluminium alloys. This project aimed therefore to investigate and create a simple method for comparing the catalytic effect on oxidation for metals, and use this method to evaluate the degradation rate of biodiesel in contact with aluminium alloys. Different heating methods and coating materials were tested using the biodiesel RME to develop the testing procedure. When a test procedure was established, three filter houses made from cast aluminium alloy and three aluminium ingots with different amount of copper were immersed in RME and the stability was evaluated. The results showed that using an oven at 80 °C to investigate the stability provided the most repeatable results, and the spray paint Auto K billack spray Universal appeared to be compatible to use with RME. The inner untreated surface of the fuel filter houses did not seem to increase the oxidation rate of biodiesel. Aluminium alloys with higher copper content degraded RME more than aluminium alloys with little/no copper, if the surface had been treated mechanically, but not to a large extent. This concludes that aluminium alloys may reduce the stability of biodiesel if it contains much copper and if the surface of the alloy has been treated. However, the detected reduction on oxidation stability could depend on other factors, and therefore it is recommended to conduct further experiments on test the aluminium alloys.

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  • 27.
    Kocak, Zeko
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering.
    Anaerobic digestion in continuous stirred tank reactors and plug flow reactors:: Comparison study concerning process performance2022Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The use of municipal waste to produce renewable energy, in the form of biogas, fulfils eight of Sweden's sixteen environmental quality objectives. The most common technology to produce biogas is anaerobic digestion (AD). Two common types of AD processes are continuously stirred reactors (CSTR) and plug flow reactors (PFR). The thesis aims at directly comparing the two reactor configurations using the same substrate mix. For this, two PFRs (PFR-T and PFR-A) and three CSTRs (D1-R, D2-NR and C1-NR) were setup. All reactors were operated at the same organic loading rate (5.2 g VS/L-day), hydraulic retention time (30 days) and operational temperature (52°C). During the project, various parameters were measured to evaluate the reactor performance, such as pH, total gas volume and gas composition, FOS/TAC (organic acids/alkalinity), volatile fatty acids (VFA), ammonium-nitrogen concentration, and solid and volatile solid of digestate.  

    The study result was divided into two sections. Section 1 summarises the start-up period (42 days), where the CSTRs and the PFRs were operated under non-recirculation mode. The start-up period was done to ensure the stability of the reactors and was concerned with achieving a similar baseline for performance. For the start-up period, the specific methane production between D1-R and D2-NR varied by 2% while the variation between C1-NR and D2-NR was 8%. Likewise, for the ammonia concentration, the difference between D1-R and D2-NR was 2%, while C1-NR differed by 9% from D2-NR. Based on these findings, the decision was taken to exclude reactor C1-NR from the experimental period of the project. 

    Section 2 compares the PFR and CSTR. One CSTR was operated with 30% recirculation of digest, while the other CSTR was operated in non-recirculation mode. The two PFRs were operated with recirculation of digestate. The experiments showed that the PFRs outperformed both CSTRs regarding the specific methane production. The PFRs produced 395±93 (N)L/kg-VS and 372±42 (N)L/kg-VS. In contrast, the CSTR with recirculation reached 280±10 (N)L/kg-VS and the non-recirculated CSTR produced 250±7 (N)L/kg-VS. The NH4+-N levels for the PFRs and CSTRs showed a 1 g/L difference, with a higher value for the PFRs (2.53±0.39 g/L for PFR-A, and 2.73±0.43 g/L for PFR-T). One of the significant differences between the recirculated and the non-recirculated CSTRs was the VFA concentration. The VFA concentration in the recirculated and non-recirculated reactor was 1.05±0.90 g/L and 0.43±0.25 g/L, respectively. The VFA concentration for the two PFRs was on average 0.28±0.12 g/L and 0.40 ±0.16 g/L. The degree of degradation in the CSTRs was 90-91% compared to 63-65% in the PFRs. The degree of degradation is possibly miscalculated and shows an inconsistency between the reactor performance in terms of specific methane production. 

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  • 28.
    Kong-Win Chang, James
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Energy and Climate Studies, ECS. Technical University of Lisbon, Instituto Superior Técnico.
    COMPARATIVE ENERGY AND GREENHOUSE GAS ANALYSES BETWEEN SMALL- AND LARGE-SCALE SUGARCANE PRODUCTION IN MAURITIUS2013Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This study uses energy and greenhouse gas (GHG) balances to evaluate how the scale of sugarcane cultivation affects the performance of a sugarcane bioenergy system generating exportable electricity from bagasse. Small-, medium-, large- and miller-planter systems, with cane field areas of less than 10 ha, 10 – 42 ha, 42 – 2000 ha, more than 2000 ha respectively, were modelled. Each of them also has different combinations of manual and mechanical agricultural operations, resulting in different cane yields.

    Miller-planter system (fully mechanised) performs best with energy yield ratio of 10.99, GHG emissions in bagasse electricity of 0.0633 kg CO2eq/kWh and avoided life cycle GHG emissions of 82.07% when replacing electricity from coal, whereas small-planter system (fully manual) has the worst performance with energy yield ratio of 6.82, GHG emissions in bagasse electricity of 0.0881 kg CO2eq/kWh and avoided life cycle GHG emissions of 75.03% when substituting electricity from coal.

    Sensitivity analyses show that relative performances of all sugarcane planter systems both in terms of energy and GHG emissions are not significantly affected by variations in bagasse allocation factor, in sugarcane yield and in fertiliser input (the most energy-intensive and GHG-emitting component). Moreover, they confirm miller-planter system as the overall best performer and indicate that increasing small-planters’ cane yield is the critical measure to improve their energy analysis performance. In terms of the nature of agricultural operations, mechanical operations do not necessarily require more input energy than their manual counterparts, contrary to common belief. This is the case for fertilisation, irrigation and cane loading. Fully mechanised sugarcane production at miller-planter scale is therefore strongly encouraged.

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  • 29.
    Larsson, Mårten
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    Grönkvist, Stefan
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    Factors that influence the development of biogas: Report from an f3 R&D project2013Report (Other academic)
  • 30.
    Lefvert, Adrian
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Energy Processes.
    Grönkvist, Stefan
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Energy Processes.
    Lost in the scenarios of negative emissions: The role of bioenergy with carbon capture and storage (BECCS)2024In: Energy Policy, ISSN 0301-4215, E-ISSN 1873-6777, Vol. 184, article id 113882Article in journal (Refereed)
    Abstract [en]

    Bioenergy with carbon capture and storage (BECCS) can be a useful and cost-effective climate change mitigation tool but it is reliant on economic incentives. With this policy perspective article we question the ongoing discussion about the use of biomass for BECCS with basis in three points: (1) under the enhanced transparency framework under the Paris agreement, all parties to the agreement will use the same guidelines to estimate emissions by sources and removals by sinks, in which the emissions and removals in connection to cultivation of biomass are accounted for in the land-use, land-use change and forestry (LULUCF) sector, (2) adding carbon capture to existing processes may lead to a shift in products from that process rather than an increase in biomass use, and (3) BECCS requires substantial financial incentives. With basis in these points, we argue that a certification framework for BECCS that contradicts the guidelines of the Intergovernmental Panel on Climate Change (IPCC) risks unnecessarily hindering deployment of a potentially cost-effective climate change mitigation tool.

  • 31.
    Lopes, Merwyn
    KTH, School of Industrial Engineering and Management (ITM), Industrial Ecology.
    Feasibility study: Biogas in Sonderborg2009Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The purpose of this feasibility study has been to guide decision makers in the implementation of abiogas project for the region of Sønderborg, Denmark. The project has been part of Feasibility studies envisioned in the Master Plan for Sønderborg to go carbon neutral by 2029. The study tried to evolve abest alternative for the city and gives a ready document to refer all aspects of biogas.

    The intensive industrial farming in Sønderborg needs to evolve to compare favorably with the situationin other regions of Denmark. The interests of various stakeholders in the waste cycle should be alignedwith that of farming. Interesting developments in the Bioenergy space hold promise for farmers to usetheir capacities for additional or alternative livelihood in energy. The focus to promote biogas as part ofDanish energy strategy and multiply capacity over the next 3 years has attracted numerous biogas proposals all over Denmark.

    This study had started off with identifying and estimating very obvious substrate sources. At verymoderate assumptions the value of methane in these sources has been estimated at 9 million m3. Thispotential could easily be increased if economically feasible substrates like energy crops and algae areadded. The SWOT analysis of pig farming in the region brings out the perspectives of farming direction in the near future. The 5 scenarios developed help the decision maker understand the various aspects thatneed to be carefully considered when planning the plant. The best case scenario for the city would bethe energy mosaic scenario which would integrate the high tech focus of local industry, a renewable energy source and a showcase project to make the region stand out among the other regions focused inthe climate change debate.

    The technological system analysis should help decision makers understand the stakeholders and the various dimensions in biogas that although complicated are manageable. The business case approach to identify utilization of energy and its costs gives a clear picture on the need for using the energy in CHP.The present focus by potential investors on government subsidies to calculate profitability needs to be understood in the context of other similar plants accepting present subsidy levels and the societal benefits, which unfortunately cannot be valued in money terms.

    At the center of all this is the need for proper stakeholder management within a bound timeframe asidentified by the “Create acceptance process”. The various tools and data are all present in this study,that only need to be arranged and presented by the company eventually handling the strict Projectmanagement goals of this project.

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  • 32.
    Lorenzi, Guido
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology. IN+, Instituto Superior Técnico, Universidade de Lisboa, Avenida Rovisco Pais 1, Lisbon, 1049-001, Portugal.
    Gorgoroni, M.
    Silva, C.
    Santarelli, Massimo
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology. Department of Energy (DENERG), Politecnico di Torino, Corso Duca Degli Abruzzi, 24, Turin, 10129, Italy.
    Life cycle assessment of biogas upgrading routes2019In: Innovative Solutions for Energy Transitions, Elsevier, 2019, Vol. 158, p. 2012-2018Conference paper (Refereed)
    Abstract [en]

    The upgrading of biogas to biomethane, by removing contaminants and carbon dioxide, is a treatment that allows this gaseous fuel to reach the specifications suitable for the injection in the natural gas grid and the use as vehicle fuel. This pathway enables the conversion of wet biomass into a perfect substitute of natural gas. Biogas upgrading is usually performed through CO2 removal and the most diffused method is water scrubbing. However, the embedded CO2 could be directly recycled into methane through a high-temperature co-electrolysis process followed by a methanation step, thus increasing the yield of biomethane for the same biogas inlet. In this paper the environmental impacts of two routes for biomethane production are compared in the framework of the Life Cycle Assessment (LCA) methodology. A sensitivity analysis for different shares of renewable content in electricity has been carried out. The results show that the large need for electrical energy penalizes the electrolytic process for renewable contents of the electricity which are not close to 100%.

  • 33.
    Lönnqvist, Tomas
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Energy and Climate Studies, ECS.
    Silveira, Semida
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Energy and Climate Studies, ECS.
    Enhancing the biogas potential from residues and energy crops in Sweden2010Conference paper (Other academic)
    Abstract [en]

    Gas has played a marginal role in the Swedish energy system not only because Sweden lacks fossil gas resources but also due to the lack of specific policies to develop the segment. This contrasts with the present situation in many other European countries where gas grids and markets are well developed. More recently, changing demand patterns in the transport sector and stringent environmental policies have triggered the development of biogas and provided a strong incentive for the development of infrastructure for biomethane in many Swedish towns. On-going initiatives often combine public and private efforts mainly at the municipal level. They build upon new opportunities in the transport sector and, thus, the biogas is upgraded to biomethane to fulfil the standard requirements of vehicle engines. However, biomethane production and infrastructural efforts have not always been in phase with the rapid expansion of the vehicle fleet.Only a small part of the practical production potential for biogas has been realized in Sweden so far. There is considerable potential for further expansion based on agricultural, urban and industrial residues, but also energy crops. However, assessments regarding the potential for energy crops in Sweden are rather divergent. This paper provides a comparison between different Swedish assessments and also European ones and further discusses the practical potential for biogas generation in Sweden. Immediate opportunities for biogas generation are identified. The study results from a collaboration between the division of Energy and Climate Studies at KTH and Fortum Värme.

  • 34. Marques, W. L.
    et al.
    Mans, R.
    Henderson, R. K.
    Marella, E. R.
    Horst, J. T.
    Hulster, E. D.
    Poolman, B.
    Daran, J. -M
    Pronk, J. T.
    Gombert, A. K.
    van Maris, Antonius J. A.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Industrial Biotechnology.
    Combined engineering of disaccharide transport and phosphorolysis for enhanced ATP yield from sucrose fermentation in Saccharomyces cerevisiae2018In: Metabolic engineering, ISSN 1096-7176, E-ISSN 1096-7184, Vol. 45, p. 121-133Article in journal (Refereed)
    Abstract [en]

    Anaerobic industrial fermentation processes do not require aeration and intensive mixing and the accompanying cost savings are beneficial for production of chemicals and fuels. However, the free-energy conservation of fermentative pathways is often insufficient for the production and export of the desired compounds and/or for cellular growth and maintenance. To increase free-energy conservation during fermentation of the industrially relevant disaccharide sucrose by Saccharomyces cerevisiae, we first replaced the native yeast α-glucosidases by an intracellular sucrose phosphorylase from Leuconostoc mesenteroides (LmSPase). Subsequently, we replaced the native proton-coupled sucrose uptake system by a putative sucrose facilitator from Phaseolus vulgaris (PvSUF1). The resulting strains grew anaerobically on sucrose at specific growth rates of 0.09 ± 0.02 h−1 (LmSPase) and 0.06 ± 0.01 h−1 (PvSUF1, LmSPase). Overexpression of the yeast PGM2 gene, which encodes phosphoglucomutase, increased anaerobic growth rates on sucrose of these strains to 0.23 ± 0.01 h−1 and 0.08 ± 0.00 h−1, respectively. Determination of the biomass yield in anaerobic sucrose-limited chemostat cultures was used to assess the free-energy conservation of the engineered strains. Replacement of intracellular hydrolase with a phosphorylase increased the biomass yield on sucrose by 31%. Additional replacement of the native proton-coupled sucrose uptake system by PvSUF1 increased the anaerobic biomass yield by a further 8%, resulting in an overall increase of 41%. By experimentally demonstrating an energetic benefit of the combined engineering of disaccharide uptake and cleavage, this study represents a first step towards anaerobic production of compounds whose metabolic pathways currently do not conserve sufficient free-energy.

  • 35.
    Mellin, Pelle
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Kantarelis, Efthymios
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Yang, Weihong
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    CFD approach to investigate fast pyrolysis by pre-heated steam, in a fluidized bed reactor2012Conference paper (Other academic)
  • 36.
    Mellin, Pelle
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Zhang, Qinglin
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Kantarelis, Efthymios
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Zhou, Chunguang
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Yang, Weihong
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Accuracy and Potential Use of a Developed CFD-pyrolysis Model for Simulating Lab-scale Bio Oil Production2012In: The 20th EU BC&E Online Proceedings 2012, 2012, p. 953-959Conference paper (Other academic)
    Abstract [en]

    The paper describes development of a CFD¬pyrolysis model using an Eularian-Eularian framework with an implemented pyrolysis reaction model. The CFD¬pyrolysis model is used to simulate the bubbling fluidized bed reactor integrated in a new experimental fast pyrolysis process for bio oil production. The model is compared to experiments in aspect of outlet gas composition, temperature and bed height. Tar behavior and yield of bio oil are illustrated and a parametric study investigates impact of flow rate and temperature on bio oil yield. The results show a tolerable fit compared to measurements and reasonable tendencies in the parametric study.

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    2DO.8.2_20th_2012
  • 37.
    Menya, E.
    et al.
    Makerere Univ, Coll Engn Design Art & Technol, Dept Mech Engn, POB 7062, Kampala, Uganda.;Gulu Univ, Dept Biosyst Engn, POB 166, Gulu, Uganda..
    Olupot, P. W.
    Makerere Univ, Coll Engn Design Art & Technol, Dept Mech Engn, POB 7062, Kampala, Uganda..
    Storz, H.
    Thuenen Inst Agr Technol, Bundesallee 47, D-38116 Braunschweig, Germany..
    Lubwama, M.
    Makerere Univ, Coll Engn Design Art & Technol, Dept Mech Engn, POB 7062, Kampala, Uganda..
    Kiros, Yohannes
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Process Technology.
    Characterization and alkaline pretreatment of rice husk varieties in Uganda for potential utilization as precursors in the production of activated carbon and other value-added products2018In: Waste Management, ISSN 0956-053X, E-ISSN 1879-2456, Vol. 81, p. 104-116Article in journal (Refereed)
    Abstract [en]

    In this study, 13 rice husk (RH) varieties from 4 agro-ecological zones in Uganda were characterized, NaOH-pretreated, and evaluated for their potential utilization as precursors for production of bio-oil, ash, char, and activated carbon for selected applications. RH varieties were characterized through particle size analysis, bulk density, proximate and ultimate analyses, specific surface area, pore volume, as well as lignocellulosic and inorganic compositions. Selected RH varieties were subsequently pretreated at NaOH concentrations of 1-4%w/v, using pretreatment ratios of 5 g RH: 40 mL NaOH. Properties varied among RH varieties, suiting them as feedstocks for different applications. Upland rice husk varieties are more suited precursors for production of bio-oil, and activated carbon due to their relatively lower ash content, higher specific surface area, as well as higher volatile matter and fixed carbon contents. Upland rice husks could as well be employed in the preparation of electrodes for electrochemical devices, due to their relatively higher specific surface area. A high ash content (21-32% dry basis) of lowland rice husks presents good prospects for their calcination, since larger amounts of rice husk ash could be obtained, and employed in different applications. Lowland rice husk varieties could also be more suited precursors for production of char for soil amendment, due to their relatively higher ash content, which subsequently increases their char yields. However, alkaline pretreatment of rice husks using 2-4%w/v NaOH can reduce the ash content by as much as 74-93%, depending on the rice husk variety, which paves way for utilizing rice husks with a high ash content in different applications. Aside from ash reduction, the enhanced specific surface area (1.2-1.7 m(2) g(-1)), volatile matter (68-79%db) and fixed carbon (19-24%db) contents of NaOH-pretreated rice husks suggests they are more suited feedstocks than when employed in their raw form, for production of bio-oil, as well as activated carbon.

  • 38.
    Mesfun, Sennai
    et al.
    RISE Res Inst Sweden, Stockholm, Sweden..
    Engvall, Klas
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Process Technology.
    Toffolo, Andrea
    Luleå Univ Technol, Dept Engn Sci & Math, Energy Sci Div, Luleå, Sweden..
    Electrolysis Assisted Biomass Gasification for Liquid Fuels Production2022In: Frontiers in Energy Research, E-ISSN 2296-598X, Vol. 10, article id 799553Article in journal (Refereed)
    Abstract [en]

    Gasification is a promising pathway for converting biomass residues into renewable transportation fuels and chemicals needed to comply with the ambitious Swedish environmental targets. The paper investigates the integration of a molten carbonate electrolysis cell (MCEC) in biofuel production pathway from sawmill byproducts, to improve the performance of gas cleaning and conditioning steps prior to the final conversion of syngas into liquid biofuels. The energy, material, and economic performance of process configurations with different gasification technologies are simulated and compared. The results provide relevant information to develop the engineering of gas-to-liquid transportation fuels utilizing renewable electricity. The MCEC replaces the water-gas shift step of a conventional syngas conditioning process and enables increased product throughput by as much as 15%-31%. Depending on the process configuration and steam-methane reforming technology, biofuels can be produced to the cost range 140-155 euro/MWh in the short-term.

  • 39.
    Niska, John
    et al.
    Swerea MEFOS, Heating and Metalworking Department.
    Grip, Carl-Erik
    Luleå University of Technology, Division of Energy Science.
    Mellin, Pelle
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Investigating Potential Problems and Solutions of Renewable Fuel Use in Steel Reheating Furnaces2013Conference paper (Other academic)
    Abstract [en]

    Implementing renewable fuels in steel reheating furnaces can reduce carbon dioxide emissions from fossil fuels, so the steel industry is interested in finding the optimal method of implementation. The relatively low cost of solid biofuels from forest products make them an attractive candidate, but there is a risk of reaction between pellets ash and furnace brick. Therefore a test was conducted with wood pellets ash on a furnace brick to test the sensitivity to pellets ash. One problem is the formation of a glassy phase due to the interaction of furnace refractories with pellets ash. The risk for the formation of a glassy phase depends on the composition of the refractory, composition of the ash and the furnace conditions, for example, a glassy phase was found to form on a chamotte refractory furnace brick when a pellets ash and the brick were heated to 1200°C.

    One method to analyze the risk for volatile and low melting point compounds from solid biofuels is to use a tertiary phase diagram to divide various components in the ash. Oxides and compounds rich in the alkali metals (Na and K) tend to form volatile compounds. These alkali metal oxides together with silica can give low melting point phases for compositions near the bottom of this diagram. Ash compositions near the top of the diagram which are rich in CaO and MgO tend to have higher melting points. The wood pellets ash investigated was analysed and found to contain a large percentage of Ca, Si and Mg, expressed as CaO (44.4%), SiO2 (14.6%) and MgO (10.1%) and relatively modest amounts of the alkali metals Na and K expressed as Na2O (3.5%) and K2O (6.2%). This mostly stem wood pellets ash could give concern with the formation of a glassy phase, so biofuels with more twigs, leaves and bark with a higher concentration of alkali metals could give even greater concerns. Therefore alternatives like gasification should be considered.

    Gasification of solid biofuels is one way to avoid ash-forming compounds in reheating furnaces. A survey was performed to evaluate different gasification technologies, as well as existing applications of syngas in other high-temperature industries.

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  • 40.
    Owusu-Agyeman, Isaac
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering.
    Plaza, Elzbieta
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering.
    Cetecioglu, Zeynep
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Resource recovery.
    A pilot-scale study of granule-based anaerobic reactors for biogas recovery from municipal wastewater under sub-mesophilic conditions2021In: Bioresource Technology, ISSN 0960-8524, E-ISSN 1873-2976, Vol. 337, article id 125431Article in journal (Refereed)
    Abstract [en]

    The influence of hydraulic retention time (HRT of 3-5 h) and temperature (20-25 degrees C) on performance and microbial dynamics of two pilot-scale upflow anaerobic sludge blanket (UASB) reactors with different granule size distribution (UASB1 = 3-4 mm and UASB2 = 1-2 mm) were investigated for 217 days. Increasing the HRT to 5 h even at a lower temperature of 20 degrees C enhanced COD removal and biogas production with average of 59 +/- 16% (up to 85%) and 73 +/- 9 L/(m3 center dot d) (up to 102 L/(m3 center dot d)) for UASB1; 63 +/- 16% (up to 85%) and 75 +/- 9 L/ (m3 center dot d) (up to 90 L/(m3 center dot d)) for UASB2, respectively. This is explained by sufficient contact time between microorganisms and substrate. Acetoclastic methanogenic activity was higher in UASB1 because Methanosaetaceae (produces methane from acetate) dominated (64 +/- 4%). However, Methanoregulaceae (29 +/- 3%) and Methanomicrobiales_unassigned (20 +/- 6%) which produce methane from H2/CO2 and formate were significant in UASB2. The extent of change in the microbial dynamics with HRT and temperature was more obvious in the smaller granule reactor.

  • 41.
    Pacini, Henrique
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Energy and Climate Studies, ECS.
    Consumer choice between ethanol and gasoline: Lessons from price mechanisms in Brazil and Sweden2009Conference paper (Refereed)
  • 42.
    Palmén, Carl
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Energy and Climate Studies, ECS.
    Silveira, Semida
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Energy and Climate Studies, ECS.
    Khatiwada, Dilip
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Energy and Climate Studies, ECS.
    Will Improved Palm Oil Yields suffice to the Development of Sustainable Biodiesel Feedstock in indonesia?2015In: CYSENI 2015, Lithuanian Institute , 2015Conference paper (Other academic)
    Abstract [en]

    By the expansion of oil palm plantations, Indonesia has become a world leading producer of crude palm oil. However, Indonesia has also been largely criticized due to issues of land use change and deforestation. The country now promotes the use of palm oil for biodiesel production as part of policies to achieve renewable energy targets. Currently yields on palm oil plantations are far from optimal. Do new policies promoting biodiesel production address the issue of yields properly? This study analyses the driving forces for the expansion of palm oil plantations in Indonesia and the palm oil yields obtained in the country. Data is collected through a multi-disciplinary structured literature review of relevant palm oil publications from the last 15 years. We identify the policies that have been put in place and the strategies used to establish palm oil plantations in the past years. We look at the newly defined policies of the Indonesian government towards renewables and climate mitigation, in particular, targets for biodiesel production and fuel substitution. The idea is to verify whether the new policy will address the low yield issue. Presently, palm oil yields are much lower in Indonesia than in neighbouring Malaysia, also a major producer. Particularly, smallholders have lower yields than private and government estate plantations. Expanding production has been focused on covering new areas with palm oil plantations and less on developing farming methods. In earlier stages, the establishment of plantations included proper education of farmers and incentives to maintain production. Smallholders nowadays start palm oil production with little or no previous experience; still they favour oil palm over traditional crops. New policies have to address farming improvements to guarantee sustainable feedstock for biodiesel.

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  • 43. Rex, E.
    et al.
    Rosander, Erica
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Røyne, F.
    Veide, Andres
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Ulmanen, J.
    A systems perspective on chemical production from mixed food waste: The case of bio-succinate in Sweden2017In: Resources, Conservation and Recycling, ISSN 0921-3449, E-ISSN 1879-0658, Vol. 125, p. 86-97Article in journal (Refereed)
    Abstract [en]

    The option of producing the chemical succinic acid from bio-based resources is well in line with current political and industrial ambitions for a bio-based economy. A little explored but intriguing biomass feedstock opportunity is food waste. Mixed food waste is especially appealing as it represents less resource competition than more homogenous food waste fractions. The feasibility of producing succinic acid from mixed food waste depends on both technical and societal system structures. Therefore, to assess the production prospect, it is important to investigate all relevant system components. This study explores from such multiple perspectives the feasibility of chemical production as a viable added pathway for mixed food waste, using microbial production of succinic acid from municipal solid waste in Sweden as an example. The perspectives explored are: 1) feedstock feasibility, 2) societal drivers and barriers for technology progress, and 3) resource availability. Findings show that even though, from a technical feasibility and resource availability perspective, production seems possible, it lacks institutional support and actor commitment and alignment for development in Sweden. Findings also show that a holistic and interdisciplinary systems perspective contributes valuable insight when assessing prospects for bio-based chemicals.

  • 44.
    Sababi, Majid
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Pan, Jinshan
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Sandberg, O.
    Electrochemical polarization measurements of tooling alloys in pyrolysis oil2011In: European Corrosion Congress 2011, EUROCORR 2011, 2011, p. 981-Conference paper (Refereed)
    Abstract [en]

    Biofuels are more environmental friendly than fossil fuels and can be used in diesel motors and power plants, but the corrosion of materials used for these systems has to be considered. Electrochemical measurements are quick and sensitive ways to investigate corrosion properties of metallic materials, however, the medium should be conductive (i.e., electrolyte) in order to perform such measurements. Pyrolysis oil is one kind of biofuels, which has a high aqueous content, a low pH and a high conductivity, and thus electrochemical measurements are feasible. In this study, cyclic polarization measurements were performed to investigate the corrosion behavior of two nitrogen-based (Vanax 35 and Vanax 75) and one carbon-based (Elmax) tooling alloys in pyrolysis oil, and stainless steel AISI 316L was included for comparison. The samples of the tooling alloys underwent the same heat treatment, including austenitizing, quenching and tempering, to obtain proper mechanical property. The cyclic polarization measurement was performed with a scan rate 100 mV/min. The start potential was -0.2 V vs. OCP, and the final potential was set to the OCP. By an automatic setting in the software, the upward potential scan was reversed when the anodic current density reached at 0.1 mA/cm 2.

  • 45.
    Said, Mahir
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Mellin, Pelle
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Zhang, Qinglin
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Liu, Hao
    State Key Laboratory of Coal Combustion, Huazhong University of Science and Technology.
    Weihong, Yang
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Litteraturstudie avseende förnybara bränslen för stålindustrin2013Report (Other academic)
  • 46.
    Salemyr, Gabriel
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Industrial Biotechnology.
    Towards a modified Calvin-Benson-Bassham cycle for improved growth in Cupriavidus necator2023Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This thesis explores a modification of the Calvin-Benson-Bassham cycle, the primary metabolic pathway for CO2 fixation, with the aim to improve its energetic efficiency. The proposed modification replaces phosphoribulokinase (PRK), a key enzyme that phosphorylates the 5-carbon sugar ribulose-5-phosphate with ATP. The replacement enzyme  is a PPi-dependent phosphofructokinase (PPi-PFK), which could potentially perform the phosphorylation using pyrophosphate instead of ATP. Since PPi-PFKs are typically specific for 6-carbon sugars, I purified and tested in vitro the activity of five candidate PPi-PFKs for phosphorylation of ribulose-5-phosphate. The experiments showed that none of the candidate PPi-PFKs were able to facilitate the phosphorylation of ribulose-5-phosphate to ribulose-1,5-bisphosphate in vitro. In another part of the thesis, I attempted to create a genetic knockout of the native PRK gene in Cupriavidus necator, a bacterium that uses the Calvin-Benson-Bassham cycle. This knockout strain was to be used for in vivo testing of PPi-PFKs. None of the candidate PPi-PFKs could functionally replace the PRK in vivo. Therefore, creation of a PPi-PFK enzyme that is active on the ribulose-5-phosphate will likely require protein engineering of substrate specificity.

  • 47. Salman, C. A.
    et al.
    Schwede, S.
    Naqvi, M.
    Thorin, E.
    Yan, Jinyue
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Energy Processes. School of Business, Society and Engineering, Mälardalen University.
    Synergistic combination of pyrolysis, anaerobic digestion, and CHP plants.2019In: Innovative Solutions for Energy Transitions, Elsevier, 2019, Vol. 158, p. 1323-1329Conference paper (Refereed)
    Abstract [en]

    The anaerobic digestion of biodegradable fraction of municipal solid waste (MSW) is a widely used process for biogas production. However, the biodegradable fraction of MSW also contains lignocellulosic waste which hinders the biogas production if added to the digester in higher quantity. So it needs to be separated from biodegradable waste and sent for alternate treatment, e.g., incineration, landfilling or compositing. Pyrolysis of lignocellulosic waste to produce biochar, syngas, and bio oil is an alternate treatment to consider. Furthermore, there is a reported correlation between the addition of biochar in the digester and higher biogas production. Previously, we coupled the pyrolysis of lignocellulosic waste with anaerobic digestion plant. Pyrolysis produces the biochar and vapors. Biochar was added in the digester to enhance the biomethane production. The vapors produced in the pyrolysis process were converted to biomethane through the catalytic methanation process. The combination gives the overall efficiency of 67%. In this work, we modified the process concept to increase the integration level of these processes. The main issue with the pyrolysis process is its heat required to operate, while some of its downstream processes also generate excess heat. In this study, the pyrolysis of lignocellulosic waste is integrated with an operating combined heat and power (CHP) plant, by using its existing infrastructure for heat transport among different pyrolysis operations. The combustor of the CHP plant provides the heat for drying and pyrolysis while the excess heat is transferred back to the combustor. The biochar produced from pyrolysis is transported back to the digester as an adsorbent. The process simulation results show that the combined efficiency of pyrolysis with CHP plant reached 80%. If the biochar is sent back to the anaerobic digester, the synergetic efficiency of all three processes, i.e., pyrolysis-CHP and anaerobic digestion was obtained at 79.7% as compared with the 67% efficiency when the pyrolysis was only integrated with the anaerobic digestion process.

  • 48.
    Salman, Chaudhary Awais
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology. UPC Barcelona.
    TECHNO-ECONOMIC ANALYSIS OF WOOD PYROLYSIS IN SWEDEN2014Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The significance of bio fuels production is increasing as fossil fuels are being depleted and energy security is gaining importance in the final energy mix. Moreover, bio fuel production offers the potential to alleviate concerns regarding global warming and air pollution. The process scheme design and parameter value choices used in this analysis are exclusively based on research domain literature by considering the state of the art of pyrolysis technology. Henceforth, the results should not be interpreted as optimal performance of mature technology, but as the most likely performance given the current state of scientific knowledge.

    The purpose of this thesis is to study and assess the technical and economic models for the conversion of woody biomass to valuable biofuel products via fast pyrolysis. The mass rate of wood is considered as 100,000 t/y. Bio fuel production from pyrolysis is energy intensive process. Therefore, heat and energy requirement calculation for the process and optimum heat integration is necessary to improve the overall thermodynamic efficiencies for wood biomass pyrolysis. Three different cases are discussed in this thesis: 1. fast pyrolysis at 500 oC, 2. fast pyrolysis at 1000 oC   and 3. Slow pyrolysis at 500 oC.   

    Literature study was conducted for different pyrolysis processes and based on their findings and results a model was developed on excel for the calculation of mass and energy balance. Mass balance results shows that the process can be selected on the basis of final product required. It was found that fast pyrolysis at 500 oC is used when bio oil is the priority product, for maximizing the syngas yield fast pyrolysis at high temperature 800-1000 oC is preferred. Similarly slow pyrolysis is used for maximizing bio char yield. It was also found that raw material type and its pretreatment also has strong influence on the pyrolysis process and final composition of bio fuels.

    Heat flux and energy streams for the pyrolysis scheme are also designed and syngas was selected to fulfil the heat requirements for different processes alongside with pyrolysis such as drying and grinding. It was found out that syngas combustion and heat recovery from the condenser will be able to fulfill the heat demand for pyrolysis process. However the specific heat requirement for fast and slow pyrolysis process varies. According to the calculations heat flux requirement for slow pyrolysis is higher than the fast pyrolysis. An explanation for this variability of the heat for wood pyrolysis is exothermic primary char formation process competing with an endothermic volatile formation process which makes it as overall endothermic process. But pretreatment of wood or biomass in fast pyrolysis is extra burden on the total heat demand for fast pyrolysis.

    Economic assessment for the pyrolysis plants is also conducted through literature survey of already installed plants and it was found out that pyrolysis is more feasible for large production facilities. The trends shows that capital costs increase with the increase of plant size but the capital cost curve moves towards a straight line after reaching the certain value the production cost per gallon of bio fuel decreases with the increase of plant capacity. The cost of biofuel is extremely sensitive to variations in operating cost (for example, cost of feed stock such as wood and selling price of products) but is not significantly affected by the variations in capital cost.

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    Salman Chaudhary Awais_EGI-2014-088MSC_EKV1054
  • 49. Salman, Chaudhary Awais
    et al.
    Schwede, Sebastian
    Thorin, Eva
    Yan, Jinyue
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology. Mälardalen University, Sweden.
    Process simulation and comparison of biological conversion of syngas and hydrogen in biogas plants2017In: International Conference on Advances In Energy Systems And Environmental Engineering (ASEE17) / [ed] Kaamierczak, B Kutylowska, M Piekarska, K Jouhara, H Danielewicz, J, EDP Sciences, 2017, article id UNSP 00151Conference paper (Refereed)
    Abstract [en]

    Organic waste is a good source of clean energy. However, different fractions of waste have to be utilized efficiently. One way is to find pathways to convert waste into useful products via various available processes (gasification, pyrolysis anaerobic digestion, etc.) and integrate them to increase the combined efficiency of the process. The syngas and hydrogen produced from the thermal conversion of biomass can be upgraded to biomethane via biological methanation. The current study presents the simulation model to predict the amount of biomethane produced by injecting the hydrogen and syngas. Hydrogen injection is modelled both in-situ and ex-situ while for syngas solely the ex-situ case has been studied. The results showed that 85% of the hydrogen conversion was achieved for the ex-situ reactor while 81% conversion rate was achieved for the in-situ reactor. The syngas could be converted completely in the bio-reactor. However, the addition of syngas resulted in an increase of carbon dioxide. Simulation of biomethanation of gas addition showed a biomethane concentration of 87% while for hydrogen addition an increase of 74% and 80% for in-situ and ex-situ addition respectively.

  • 50.
    Samavati, Mahrokh
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology. Polytech Univ Turin POLITO, Dept Energy, Corso Duca Abruzzi 24, I-10129 Turin, Italy..
    Santarelli, Massimo
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology. Polytech Univ Turin POLITO, Dept Energy, Corso Duca Abruzzi 24, I-10129 Turin, Italy..
    Martin, Andrew R.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Nemanova, Vera
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Production of Synthetic Fischer-Tropsch Diesel from Renewables: Thermoeconomic and Environmental Analysis2018In: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 32, no 2, p. 1744-1753Article in journal (Refereed)
    Abstract [en]

    In this study, a novel integrated system for production of advanced synthetic diesel is proposed and analyzed from thermodynamic, economic, and environmental perspectives. This system consists of a solid oxide electrolyzer, entrained gasification, a Fischer Tropsch reactor (FT), and upgrading processes. Eleven different combinations of precursor syngas production through steam and CO, co-electrolysis and biomass gasification are investigated. Results show that an increasing share of produced syngas in the electrolyzer unit results in higher system efficiencies, emission savings, and levelized cost of FT diesel. Moreover, different options of heat and mass :flow recovery are considered. It is concluded that recovery of produced medium pressure steam in the system is highly beneficial and recommended. Besides, it is shown that while oxygen recovery is the best choice of mass recovery, hydrogen recovery for internal use has adverse effect on the system performance.

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