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  • 251. Billeter, J.
    et al.
    Rodrigues, Diogo
    Laboratoire d'Automatique, École Polytechnique Fédérale de Lausanne, Lausanne, CH-1015, Switzerland.
    Srinivasan, S.
    Amrhein, M.
    Bonvin, D.
    On decoupling rate processes in chemical reaction systems – Methods and applications2018In: Computers and Chemical Engineering, ISSN 0098-1354, E-ISSN 1873-4375, Vol. 114, p. 296-305Article in journal (Refereed)
    Abstract [en]

    Models of chemical reaction systems can be complex as they need to include information regarding the reactions and the mass and heat transfers. The commonly used state variables, namely, concentrations and temperatures, express the interplay between many phenomena. As a consequence, each state variable is affected by several rate processes. On the other hand, it is well known that it is possible to partition the state space into a reaction invariant subspace and its orthogonal complement using a linear transformation involving the reaction stoichiometry. This paper uses a more sophisticated linear transformation to partition the state space into various subspaces, each one linked to a single rate process such as a particular reaction, mass transfer or heat transfer. The implications of this partitioning are discussed with respect to several applications related to data reconciliation, state and rate estimation, modeling, identification, control and optimization of reaction systems.

  • 252.
    Billgren, Mikaela
    KTH, School of Chemical Science and Engineering (CHE).
    Utvärdering av Brunsa2017Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
  • 253.
    BIN HANNAN, KHALID
    KTH, School of Chemical Science and Engineering (CHE).
    Organiska kväveföreningars påverkan på vätebehandlingsanläggningens prestanda2014Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Various distillates are treated with hydrogen gas during hydrotreatment in the presence of catalyst in order to reduce the sulfur and aromatic content of the product. Optimal hydrotreater performance is essential for producing Nynas specialty oils, in order to fulfill the planned production volume and to meet the product specification. Loss of catalyst activity is inevitable during the production. To adjust for the impact of catalyst deactivation, different process variables are manipulated. Different distillates affect the catalyst in different ways due to the variation in distillate composition. Distillates with higher organic nitrogen content and running at a lower temperature tend to deactivate the catalyst more due to the adsorption of nitrogen compounds on the active sites of the catalyst and their slow nature of desorption.

    In this master thesis, different catalyst deactivation mechanisms with a focus on nitrogen deactivation have been studied. Since nitrogen is not normally measured at Nynas, nitrogen content of different distillates and products and how these values change during operation was not known. Different distillates, blend of distillates and different products were measured to estimate roughly the typical nitrogen value of the distillates and products. The temperature data inside the reactors were analyzed to calculate and plot WABT (weighted average bed temperature) during different product runs and to see whether there is a correlation between the nitrogen content of the feed and operation severity (increase in WABT). Historical process data from hydrotreater unit 2 (mostly from 2013-2014) were analyzed with a view to finding out signs of catalyst deactivation. Similar product runs were also analyzed and compared to see how the catalysts performed at different periods of time. A kinetic model, based on HDS kinetics, has been used for following up two product runs. To do so, sulfur content of the feed and product were measured. Aromatic content of the product was also measured to see whether the product was on specification.

    .From the calculation and plotting of WABTs, it could be seen that there is an increase in WABT during the product runs operating at lower temperatures and with higher nitrogen content. From the comparison of two P3 product runs at two different time periods, it could be seen that ∆T development over one bed (amount of reaction over the bed) was much lower at one time. This can possibly be a sign of catalyst deactivation since it contributed to lesser amount of reaction over the bed.

    From the calculations by using the kinetic model, it could be seen that the actual temperatures were higher than the predicted temperatures. The increase in WABTs could also be noticed. These observations can possibly be coupled with nitrogen deactivation of the catalysts.  However, more tests are required to verify whether the temperature differences were significant or not. Other parameters which are also important from product selling point of view such as viscosity, color, flash point, acid number etc. and have not been covered in this degree project need to be taken into consideration before making further conclusions.

  • 254.
    Binning, Linda
    KTH, School of Chemical Science and Engineering (CHE).
    Undersökning av titanföreningar för tillverkning av standarder vid användning av röntgenfluorescens2011Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    SECO Tools manufactures tool inserts for all types of metal cutting machining. (Ti,W)C is a common raw material used in the production. At arrival, the material (Ti,W)C is always analyzed. Titanium has previously been analysed with x-ray fluorescence spectrometry, but as the calibration has previously been performed with two different types of titanium (rutile and metallic titanium), the results has differed. Because of that, this thesis project has been devoted to analyze titanium, to find the best titanium compound for producing standards.

    The work has been performed using literature studies and many experiments in the laboratories at SECO Tools inFagersta,Sweden. This project has included about ten working weeks. In this report the analysis methods of x-ray fluorescence spectrometry and spectrophotometry is described, as the methods has been used in the experiments.

    A big problem that was discovered during this project was the big standard deviation of results for the method used for analysing titanium with x-ray fluorescence. Because of that, much time of this project has been devoted to experiments trying to reduce the standard deviation between the samples, as this is vital to performing a reliable calibration. A variety of experiments has been performed without reducing the standard deviation between the samples to below 0.2 % -units for the (Ti, W) C-samples.

  • 255.
    Birgersson, Erik
    et al.
    KTH, Superseded Departments, Mechanics.
    Nordlund, Joakim
    KTH, Superseded Departments, Chemical Engineering and Technology.
    Vynnycky, Michael
    KTH, Superseded Departments, Mechanics.
    Picard, Cyril
    KTH, Superseded Departments, Mechanics.
    Lindbergh, Göran
    KTH, Superseded Departments, Chemical Engineering and Technology.
    Reduced two-phase model for analysis of the anode of a DMFC2004In: Journal of the Electrochemical Society, ISSN 0013-4651, E-ISSN 1945-7111, Vol. 151, no 12, p. A2157-A2172Article in journal (Refereed)
    Abstract [en]

    An isothermal two-phase ternary mixture model that takes into account conservation of momentum, mass, and species in the anode of a direct methanol fuel cell (DMFC) is presented and analyzed. The slenderness of the anode allows a considerable reduction of the mathematical formulation, without sacrificing the essential physics. The reduced model is then verified and validated against data obtained from an experimental DMFC outfitted with a transparent end plate. Good agreement is achieved. The effect of mass-transfer resistances in the flow field and porous backing are highlighted. The presence of a gas phase is shown to improve the mass transfer of methanol at higher temperatures (>30 degreesC). It is also found that at a temperature of around 30 degreesC, a one-phase model predicts the same current density distribution as a more sophisticated two-phase model. Analysis of the results from the two-phase model, in combination with the experiments, results in a suggestion for an optimal flow field for the liquid-fed DMFC.

  • 256.
    Birgersson, Henrik
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Development and Assessment of Regeneration Methods for Commercial Automotive Three-Way Catalysts2006Doctoral thesis, comprehensive summary (Other scientific)
    Abstract [en]

    Car exhaust catalysts were introduced in the early 1980’s, to limit the release of pollutants such as hydrocarbons, carbon monoxide and nitrogen oxides. These catalysts contain noble metals such as palladium (Pd), platinum (Pt) and rhodium (Rh) and are able to simultaneously abate all three of the above-mentioned pollutants, hence the name three-way catalyst (TWC). The exposure to high temperatures (800-1000 °C) during operation and the presence of additives in gasoline and lubricants will, after a certain time, lower the activity of the TWC. High temperatures reduce the active area by causing the noble metals to agglomerate and sinter, whereas the additives alter the activity either by fouling the pores of the support material or by interacting with the metals.

    The main objective of this work was to develop a method which allows for the removal of contaminants (additives) from the washcoat and enables the redispersion of the active sites (noble metals), in an effort to recover lost catalyst activity. For this purpose, regeneration experiments were carried out on a wide spectrum of different commercial car exhaust catalysts.

    The influence of a thermal treatment in a controlled gas atmosphere, such as oxygen or hydrogen, and a redispersing agent, e.g. chlorine, on the activity of TWC was investigated by means of laboratory-scale activity measurements. Several complementary characterization methods such as SEM/TEM, XRD, BET, LA, XPS and TPR were employed to verify the effects of the regeneration treatments on the catalyst morphology (Papers I, II). The results show that partial regeneration of catalyst activity and noble metal dispersion was achieved after thermal treatment in an oxygen-chlorine rich atmosphere at temperatures below 500 °C. A wet-chemical regeneration treatment with dilute oxalic and citric acid solutions is evaluated in Paper III. These acidic solutions are able to dissolve and remove contaminants from the washcoat, thus partly restoring the catalyst activity.

    An investigation of the effects of an oxy-chlorine thermal treatment for regeneration of a ‘full-scale’ commercial automotive three-way catalyst was carried out (Paper IV). Improved catalyst activity for a high mileage catalyst could be observed, with emissions lowered by approximately 30 to 40 vol.% over the EC2000 driving cycle.

    The properties of fresh, aged and regenerated catalysts were then studied by means of labscale experiments, on a local as well as a global level using a mathematical model (Paper V). The model allows for comparison of the intrinsic properties of the active surface by deriving and tuning parameters of a fresh catalyst and verifying the activity of a regenerated or aged catalyst.

  • 257.
    Birgersson, K.R.
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Transport Phenomena.
    Luna, Fabio
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Transport Phenomena.
    Martínez, Joaquín
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Transport Phenomena.
    Diffusion Equation applied to Isothermal Drying of a Multicomponent Liquid Film1998In: IACChE'98: Proceedings of the 18th Inter-American Congress of Chemical Engineering, Mayagüez, Puerto Rico: University of Puerto Rico at Mayagüez (UPRM) , 1998Conference paper (Refereed)
  • 258.
    Birgersson, Marcus
    KTH, School of Chemical Science and Engineering (CHE).
    Kartläggning av källor till nickel och kadmium inom upptagningsområdet Bergvik2015Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Heavy metals in nature is a major problem to deal with. Sludge is produced at the waste water treatment plants which has major applications in areas such as agriculture due to its high phosphorus content. Phosphorus is an essential resource for plants and crops to grow. To obtain a good and effective recycling of phosphorus is therefore very important, since it is a finite resource that will run out. The problem with using phosphorous-rich sludge is that it can contain various pollutants, including nickel and cadmium, which accumulates in soil and can be used up by the crops in the fields. This means that people ingest these toxins through the food.

    Revaq is a certification system that is designed to certify the resulting sludge to show that it is of good quality in terms of purity from various toxins. Himmerfjärdsverket, owned by SYVAB where ownership is composed of several municipalities, has Revaq certified sludge which is very good to spread on farmland. Södertälje is one of the municipalities that own Himmerfjärdsverket where Telge Nät is responsible for the water sent to the waste water plant.

    In 2014 a sampling of the water at various points upstream Himmerfjärdsverket was done by Josefin Flodgren (Flodgren, 2015a), and the result was compared with previous measurements performed in 2010. It was revealed that Bergvik in Södertälje had elevated levels of cadmium in the water. Because of this Bergvik ended up on the Telge Nät action plan for 2015 to carry out upstream work to identify potential sources of emissions of nickel and cadmium in the area.

    During this work the activities connected to Bergvik was mapped. The mapping involved activities with different grading’s: A (should have the land and- environmental courts approval to practice its activity) (Södertälje kommun, 2015), B (needs approval from the county administrative board) (Södertälje kommun, 2015), C (only notifiable to the regulatory agency) (Södertälje kommun, 2015) and U (self-monitoring) (Ockelbo kommun, 2015). Extraneous water, also called surface water, was also surveyed. Bergvik was divided into 16 zones to carry out assessments of the areas in which had the greatest potential to contribute with nickel and cadmium to wastewater.

    The results of the survey showed that no A or B activities were located in the area. Four U activities could be traced in the area, a boat club, a metal and- forging company, a blast and- painting company and a business that provided and sold machines for gas cleaning.

    The mapping of the extraneous water revealed that 41 homes had extraneous water connected to the wastewater network. Three gullies were located that were connected to the wastewater network.

    Literature studies showed that the greatest risk of pollution comes from households. Therefore, it was considered important to focus on this to come to grips with the problem of the elevated levels of cadmium.

    The result showed that three of the sixteen zones were given high priority to perform more thorough examination to check if they could contribute with the release of nickel and/or cadmium.

    An action plan was developed for each type of emission source from operations, extraneous water as well as for households. From the boat club, emissions of cadmium could come from painting with antifouling, therefore, it is recommended to use more environmentally friendly types of boat paints. From the blast and-painting company nickel and cadmium can come to the drain from old paint ormetal surfaces when blasted, which are then flushed away. Proposals to dispose of the waste on site was recommended. The stormwater drains that were connected to the sewerage network were instead advised to be connected to the storm water network instead. More detailed studies with measurements on each affected area needs to be performed to verify where the emissions are coming from. Further work for Telge Nät were developed where the proposal was to carry out the measurements, for example with the measuring instrument Ecoscope, to detect the emission of nickel and cadmium. Measurements should be performed at the recommended zones or at the identified activities as well as the drains.

  • 259.
    Biswas, Amit Kumar
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Thermochemical behavior of pretreated biomass2011Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    Mankind has to provide a sustainable alternative to its energy related problems. Bioenergy is considered as one of the potential renewable energy resources and as a result bioenergy market is also expected to grow dramatically in future. However, logistic issues are of serious concern while considering biomass as an alternative to fossil fuel. It can be improved by introducing pretreated wood pellet.

    The main objective of this thesis is to address thermochemical behaviour of steam exploded pretreated biomass. Additionally, process aspects of torrefaction were also considered in this thesis. Steam explosion (SE) was performed in a laboratory scale reactor using Salix wood chips. Afterwards, fuel and thermochemical aspects of SE residue were investigated. It was found that Steam explosion pretreatment improved both fuel and pellet quality. Pyrolysis of SE residue reveals that alerted biomass composition significantly affects its pyrolysis behaviour. Contribution from depolymerized components (hemicellulose, cellulose and lignin) of biomass was observed explicitly during pyrolysis. When devolatilization experiment was performed on pellet produced from SE residue, effect of those altered components was observed. In summary, pretreated biomass fuel characteristics is significantly different in comparison with untreated biomass. On the other hand, Process efficiency of torrefaction was found to be governed by the choice of appropriate operating conditions and the type of biomass.

  • 260.
    Biswas, Amit Kumar
    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, Wlodzimierz
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Devolatilization characteristics of steam explosion pretreated wood pelletIn: Fuel processing technology, ISSN 0378-3820, E-ISSN 1873-7188Article in journal (Other academic)
  • 261.
    Biswas, Amit Kumar
    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, Wlodzimierz
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Steam pretreatment of Salix to upgrade biomass fuel for wood pellet production2011In: Fuel processing technology, ISSN 0378-3820, E-ISSN 1873-7188, Vol. 92, no 9, p. 1711-1717Article in journal (Refereed)
    Abstract [en]

    Steam explosion (SE) pretreatment is served to separate the main components of woody biomass. In general there is a noticeable gap in literature in terms of application of steam explosion process to upgrade biomass fuel for wood pellet production. In order to study the influence of steam explosion pretreatment on biomass fuel, Salix wood chips was used as raw material. Four different SE experiments were performed by varying two key process factors; time and temperature. Elementary quality and ash properties of the pretreated residue were investigated. Moreover, physical and thermochemical properties of the pellet, produced from the residue, were also investigated. Reduction in ash content especially in alkali metals was observed in steam treated residue. Pretreatment of biomass also enhanced carbon content and reduced oxygen amount in the fuel which enhanced the heating value of the fuel. Moreover, pretreatment enhanced pellet density, impact resistance, and abrasive resistance of pellet. However, small degradation in ash fusion characteristics and char reactivity was also observed as the severity of the process increased.

  • 262.
    Bitar, Mriana
    KTH, School of Chemical Science and Engineering (CHE).
    Varifrån kommer metallerna i Vallentunasjön?2016Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
  • 263.
    Bitar, Petra
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH).
    En undersökning av Rönningesjöns miljötillstånd, särskilt när det gäller näringsämnen2018Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Rönningesjön is a 4.5-meter-deep lake situated in a geological default, 25 km north of Stockholm in Täby municipality. It is strongly impacted by roads and the local societies Löttingelund and Gribbylund. To the east of Rönningesjön, a large forested recreation area is found, with the name Skavlöten. The goal of this work is to investigate the impact of nutrients on the lake in 2018. The field work was performed in april 2018. Samples were taken in creeks an in rivers running into the lake, the outlet and in the lake itself. The analyses of the samples were made in a laboratory at The department of Chemistry, KTH.

    In the northern part of the lake, floating wetlands have been installed to improve the water quality. A stream of water is running through the lake from north to south, and finally, out to Hägernäsviken, a part of the Baltic Sea. The water is divided into an upper part (the epilimnion) above 2.5 m depth and a lower part, below 2.5 m depth (hypolimnion). The lake is strongly eutrophiated and the constructed wetland leaks nutrients into the lake. The cleaning of the storm water should be improved.

  • 264.
    Bjervås, Jens
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH).
    Simulation of dry matter loss in biomass storage2019Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Material degradation and a decrease of fuel quality are common phenomena when storing biomass. A magnitude of 7.8% has been reported to degrade over five months when storing spruce wood chips in the winter in Central Europe. This thesis presents a theoretical study of biomass storage. It includes investigations of bio-chemical, chemical and physical processes that occur during storage of chipped woody biomass. These processes lead to degradation caused by micro-activity, chemical oxidation reactions and physical transformation of water. Micro-activity was modeled with Monod kinetics which are Michaelis-Menten type of expressions. The rate expressions were complemented with dependency functions describing the impact of oxygen, moisture and temperature. The woody biomass was divided into three fractions. These fractions represent how hard different components of the wood are to degrade by microorganisms. Chemical oxidation was modeled as a first order rate expression with respect to the active components of the wood. Two different cases have been simulated during the project. Firstly, an isolated system with an initial oxygen concentration of air was considered. This case displayed a temperature increase of approximately 2˚C and a material degradation less than 1%. The second case considered an isolated system with an endless depot of oxygen. This case resulted in degradation losses around 0.45-0.95% in the temperature range between 65-80˚C during approximately 300 days of storage. The temperature increased slowly due to chemical oxidation.

  • 265.
    Björkbacka, Åsa
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry. Show more KTH Royal Inst Technol, Sch Chem Sci & Engn, SE-10044 Stockholm, Sweden..
    Hosseinpour, Saman
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science. Show more KTH Royal Inst Technol, Sch Chem Sci & Engn, SE-10044 Stockholm, Sweden..
    Leygraf, Christofer
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science. Show more KTH Royal Inst Technol, Sch Chem Sci & Engn, SE-10044 Stockholm, Sweden..
    Jonsson, Mats
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry. Show more KTH Royal Inst Technol, Sch Chem Sci & Engn, SE-10044 Stockholm, Sweden..
    Radiation Induced Corrosion of Copper in Anoxic Aqueous Solution2012In: Electrochemical and solid-state letters, ISSN 1099-0062, E-ISSN 1944-8775, Vol. 15, no 5, p. C5-C7Article in journal (Refereed)
    Abstract [en]

    The effect of gamma radiation on corrosion of copper under anoxic conditions in pure water has been studied experimentally. Copper samples submerged in water were exposed to dose rates of 0.37 or 0.77 kGy/h. Reference samples were used throughout. The copper surfaces have been examined using the techniques of SEM-EDS, IRAS, CR spectroscopy and AFM. Dissolution of copper was measured using ICP-OES. The results show that irradiated samples are more corroded than corresponding reference samples. This is also reflected by the increased concentration of copper in water after irradiation. Surface examination also reveals local corrosion features.

  • 266.
    Björkegren, Johan
    KTH, School of Chemical Science and Engineering (CHE).
    Bakterier och parasiter i dricksvatten - En studie kring dricksvattenrelaterade utbrott i Sverige, dess orsaker samt metoder för inaktivering och avskiljning2015Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
  • 267.
    Björklund, Anna
    KTH, Superseded Departments, Chemical Engineering and Technology.
    Environmental System Analysis of Waste Management: Experiences from Applications of the ORWARE Model2000Doctoral thesis, comprehensive summary (Other scientific)
    Abstract [en]

    Waste management has gone through a history of shiftingproblems, demands, and strategies over the years. In contrastto the long prevailing view that the problem could be solved byhiding or moving it, waste is now viewed as a problem rangingfrom local to global concern, and as being an integral part ofseveral sectors in society. Decisive for this view has beensociety’s increasing complexity and thus the increasingcomplexity of waste, together with a general development ofenvironmental consciousness, moving from local focus on pointemission sources, to regional and global issues of more complexnature.

    This thesis is about the development and application orware;a model for computer aided environmental systems analysis ofmunicipal waste management. Its origin is the hypothesis thatwidened perspectives are needed in waste managementdecision-making to avoid severe sub-optimisation ofenvironmental performance. With a strong foundation in lifecycle assessment (LCA), orware aims to cover the environmentalimpacts over the entire life cycle of waste management. It alsoperforms substance flow analysis (SFA) calculations at a ratherdetailed level of the system.

    Applying orware has confirmed the importance of applyingsystems perspective and of taking into account site specificdifferences in analysis and planning of waste manage-ment,rather than relying on overly simplified solutions. Somefindings can be general-ised and used as guidelines to reduceenvironmental impact of waste management. Recovery of materialand energy resources from waste generally leads to netreductions in energy use and environmental impact, because ofthe savings this brings about in other sectors. Waste treatmentwith low rate of energy and materials recovery should thereforebe avoided. The exact choice of technology however depends onwhat products can be recovered andhow they are used.

    Despite the complexity of the model and a certain degree ofuser unfriendliness, involved stakeholders have expressed thevalue of participating in orware case studies. It providesimproved decision-basis, but also wider understanding of thecomplexity of waste management and of environmental issues ingeneral.

    The thesis also contains a first suggestion of a frameworkto handle uncertainty in orware, based on a review of types ofuncertainty in LCA and tools to handle it.

  • 268.
    Björlenstam, Philip
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Corrosion Science.
    Evaluation of corrosion in crevices in screw joints2011Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    In this Master of Science thesis screws with different coatings were exposed to an accelerated corrosion test in order to investigate the corrosion development. The test matrix constituted of hexagonal and flange screws (fastened on frames) coated with either zinc/iron (ZnFe) or a flake system of aluminum and zinc (GEOMET). The corrosion results were analyzed by means of X-ray diffraction (XRD). In this study the screws were also crosscut and analyzed by means of FEG-SEM in order to determine the thickness and the elemental content of the surface coating. The result of the corrosion test showed that the screws coated with GEOMET showed a very good corrosion resistance whilst the screws coated with ZnFe failed to fulfill the demands on corrosion resistance of Scania.

  • 269.
    Björling, Alexander
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH).
    Green Modification of Corn-Based Polysaccharide Substrates Towards Enhanced Compatibilization for Bioplastics2018Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The government is introducing new guidelines and policies regarding the raw materials for commercial plastics. They suggest that the replacement of oil-based plastics is necessary. The replacement shall be bio-based raw materials to achieve a sustainable plastic community. For example, Sweden is supposed to be a fossil-free country by 2030. To be able to achieve these replacements, research of creating bio-based plastics out of different bio-based raw materials is needed. A good example of this type of research is the purpose of the EU project BARBARA.

    The goal of the EU funded project BARBARA is to develop polysaccharide-based engineering bioplastics, that are both sustainable and competitive against other commercial plastics. The BARBARA project involves extraction and chemical modification of bio-based molecules and functional additives from agricultural residues, like corn, as well as their compatibility with commercial bioplastics. The product is later supposed to be used in advanced engineering applications such as automotive and construction.

    The scope of the project in this report was to evaluate esterification methods for four starch grades with different amylose/amylopectin ratios by applying green chemistry to enhance the material properties of starch. The results were evaluated based on the reaction efficiency on the degree of substitution of the hydroxyl groups (DS), the hydrophilicity, the molecular structure and the thermal stability after modification.

    The results from the Fourier-Transform Infrared Spectroscopy showed that the DS increased by longer reaction time for all the starches. The analysis by High Performance Liquid Chromatography showed that the DS increased by the reaction time for the native and waxy starch. The results also suggest that there is an optimum reaction time for the two high amylose starches. The analysis by X-Ray Diffraction showed that the crystallinity of all the starches had decreased after the modification and in some cases might have transitioned into an amorphous structure. The thermogravimetric analysis showed that the starches had become more hydrophobic after modification. The water content in the samples decreased by longer reaction time. The thermogravimetric analysis also showed that the thermal stability had been enhanced after the modification.

  • 270.
    Bladholm, Viktor
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH).
    Organic Fillers for Solid Rocket Fuel2018Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Liquid propellant and solid propellant rockets are the most commonly used rockets

    Liquid propellant rockets have the advantage of being manoeuvrable with a high specific performance while they exhibit problems with storage and a complex design. Solid propellant rockets offer simplicity and are storable while they have a large environmental impact and could be difficult to handle. A third type of rocket, hybrid propellant rocket has the potential to combine the simplicity of solid propellant rocket with the manoeuvrability of liquid propellant rockets. While the hybrid propellant rocket offers advantages over liquid propellant and solid propellant rocket it have problems with its fuel which have a low regression rate and low density. Organic fillers were evaluated since they may increase in the regression rate and the density of the solid fuel. 50 organic fillers were assessed with regards to their specific impulse, density, cost and handling properties. The organic fillers with the most promising properties were then experimentally evaluated. Thermogravimetric analysis (TGA), isothermal weight loss test, compatibility test and differential scanning calorimetry analysis were conducted. The results indicate that hexamine, fluorene, anthracene and 1,4-dicyanobenzene are the most suitable organic fillers of those evaluated..

  • 271. Blasiak, W.
    et al.
    Yang, W.
    Ekman, T.
    von Schéele, Johan
    KTH.
    Flameless oxyfuel combustion and its applications2013In: Oxygen-Enhanced Combustion, Second Edition, CRC Press , 2013, p. 495-516Chapter in book (Other academic)
    Abstract [en]

    Progress in combustion technologies with fossil fuel made possible use of oxygen for combustion in industrial processes, reducing drastically CO 2 and NO x emissions as well as allowing for higher productivity at highest possible level of product quality. Since the economy of oxyfuel combustion is dependent on the cost of oxygen, the availability of lowcost oxygen is critical to the application economy as well. Development of lower-cost oxygen separation techniques allows at present use of oxidizer with almost 100% content of oxygen. 

  • 272.
    Blinkovskaja, Irina
    KTH, School of Chemical Science and Engineering (CHE).
    Lanasol på bomull, ylle och fleece2015Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    A new type of natural, antimicrobial, biocompatible agent is presented. Lanasol--a brominated cyclic compound that can be extracted from red sea algae and occurs naturally was applied onto the three most commonly available fabrics: cotton, wool and fleece. Samples of the fabrics were tested for a series of properties such Antibacterial effectiveness, durability to laundering and flammability.

     

    The treated fabric surface and the Lanasol percentage present at the surface of the fabric were evaluated by performing SEM, IR and Density Archimedes. The antimicrobial activity of the coated fibres against fungi Fussarium, was assessed using qualitative Agar diffusion test.

     

    The Lanasol treated samples displayed very good antimicrobial properties compared to the untreated control samples.  It was observes that antibacterial effectives increased significantly with higher Lanasols solutions of 10% compared to 2,5%. Antibacterial properties remained effective after 10 washes but decreased visibly after 20 washes.  Anti-flammability properties were strongest in unwashed samples with considerable ignition time differences to the untreated control samples.

     

    The results obtained from the current study demonstrate that Lanasol, which has previously not been tested for textile durability, has significant potential as a new antibacterial agent. This concept opens the door to further research into the increasing the antimicrobials properties as well as enhancing the success of commercial application of Lanasol for textile treatment.

  • 273.
    Blomdahl, Caroline
    KTH, School of Chemical Science and Engineering (CHE).
    Kvantifiering och utvärdering av organiska ämnen vid en avfallsanläggning2017Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The establishment of the European Union Water Framework Directive (2000/60/EG) has created a common platform for the EU Member States regarding action in the field of waterpolicy. In 2004 the directive was implemented in the Swedish legislation and it constitutes the foundation of the water management in Sweden. The responsibility of the water management is assigned to a water authority that consists of five County Administrative Boards. The objects of their work are to attain good quality of water environment and prevent further deterioration. In order to determine the quality status of a so-called surface water body, concentration of various chemicals substances in the water are measured. Some of these substances are toxic, persistent and bioaccumulative organic pollutants. Potential sources of such substances are partly waste disposal facilities. It is therefore important for waste management operators to possess knowledge of how their activities affect the surrounding environment, which they can achieve by performing measurements and studies.

    The waste disposal facility Högbytorp in Upplands-Bro is operated by Ragn-Sells Avfallsbehandling AB and handles reception, recycling and disposal of different types of waste. This project was aimed at supplementing parts of Ragn-Sell’s earlier characterization of landfill leachate at Högbytorp and giving them an improved supervision of their emissions regarding a number of determined organic pollutants. Examples of substances included were brominated flame retardants, polycyclic aromatic hydrocarbons and perfluoroalkylated substances, which are classified as priority substances within the water policy. The project would also provide information on the extent of reduction of these substances in various leachate treatment steps at Högbytorp. To achieve these objectives, sampling and analyzeshave been performed on Högbytorp’s leachate and on their soil plant system, but also on the surface water in the nearby recipient and on treated process water sent to the wastewater treatment plant Käppala. Measured concentrations in these sampling points have been evaluated by comparing them to relevant values like environmental quality standards. Massbalances of PFOS, perfluorooctane sulfonate, was performed to understand how the substanceis affected in different treatment steps and to estimate their purification efficiency. The project's delimitations consisted of the selected organic pollutants that have been analyzed and the particular sampling points.

    The results of the evaluation of organic pollutants showed that depending on the sampling point some substances exceeded their comparative values while others measured below. However, levels of PFOS were particularly distinctive as they exceeded at least one comparative value in every sampling point. In general, higher concentrations were found in untreated leachate compared to treated leachate, indicating that Högbytorp's leachate treatment steps are able to reduce concentrations of organic pollutants in leachate. By comparing the concentration levels before and after the nitrification/denitrification treatment plant, the reduction of analyzed substances was classified as good to very good in this treatment step. Byusing mass balances regarding PFOS the purification efficiency of both the nitrification/denitrification treatment plant and the treatment ponds were estimated to be very good. A possible explanation for the reduction of PFOS was thought to be the ability of the substance to adsorb to sludge. Support to this hypothesis was given by the PFOS content measured in the sludge of the nitrification/denitrification plant.

    Measurements in the soil plant system showed lower levels of naphthalene, anthracene and fluoranthene in the area where salix grows, which indicate that the plant has a reducing effecton polycyclic aromatic hydrocarbons in the soil. However, it was not possible to estimate the purification efficiency of the soil plant system using a mass balance due to uncertain assumptions and insufficient data. When comparing concentration levels in the recipient upstream and downstream the wastefacility, increased concentrations were detected downstream, which could be a result of the waste facility's operations. Evaluation of the concentration levels of substances downstream showed that the majority was measured below the environmental quality standards. Regardingthe evaluation of the treated process water led to the wastewater treatment plant Käppala, all substances evaluated fell below the risk criteria of REVAQ meaning that the impact on these wage sludge in the wastewater treatment plant should be considered tolerable with the assumption that the process water represents the total leachate flow to the wastewater treatment plant. With only regard to tolerable influence on sewage sludge, the connection of these waters can be maintained.

    Due to the fact that most samples were taken only at one point, the results may be doubtful andtherefore misleading. In order to obtain more representative results, the sampling of this project should be supplemented with several samples taken over a longer period of time.

    Based on the results of the project, several conclusions could be drawn and proposals forfurther studies could be given. For the reason that PFOS seems to adsorb to sludge, it is relevant to look over the management of sludge removal from the nitrification/denitrificationplant and the treatment ponds. Because of the high reduction of organic pollutants in thenitrification/denitrification plant it is important to avoid flow of leachate past the plant, whichmeans that the plant’s capacity should be investigated. Since concentrations of analyzed pollutants in the recipient were higher downstream the waste facility, it is likely that emissionsoccur from the facility. It is therefore a good idea to examine potential sources of emissions within the facility area, in order to prevent emissions to the recipient.

  • 274.
    Blomfeldt, Thomas
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymeric Materials.
    Freeze-Dried Wheat Gluten-Based Foams2012Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    This thesis presents wheat gluten foams as an alternative to the available commercialfoams. Polymeric foams, like all plastics, are mostly made from petroleum, and this isaffecting the environment negatively with the emission of greenhouse gases and generation oflandfills. During the past decades, there has been a drive to replace petroleum-based plasticswith alternatives made from renewable resources. Wheat gluten has interesting and promisingproperties as an alternative resource. As a large by-product in Europe from the biofuelindustry it is largely available and at a low price.In order to develop an insulation material based on this renewable resource, foammaterials have been made by freeze-drying frozen mixtures consisting of either acommercially available wheat gluten powder or various protein rich fractions of gliadins orglutenins extracted from the commercial powder. Some of the foams were further modifiedwith the addition of glycerol as plasticizer or bacterial cellulose as a reinforcing fiber. Theresulting cellular structure was shown to depend on the initial gluten concentration, and thefraction and type of additive used. The wheat gluten foam materials contained mainly an openpore structure with average pore diameters ranging from 20 to 70 μm.The addition of glycerol and/or bacterial cellulose changed the foam structure, theprotein structure and the mechanical properties. The addition of 20 wt.% glycerol wassufficient to plasticize the foam and to achieve a low modulus and a high strain recovery, butwith glycerol the average pores size increased due to the difference in freezing conditions.The bacterial cellulose gave a small and insignificant increase in stiffness and also a moreuniform cell structure. In addition, the glycerol-containing samples had a more polymerizedprotein structure, whereas the foams containing fibers had a lower degree of polymerization.Foams made from a glutenin rich fraction were much stiffer and stronger than gliadinrich foams. The glutenin rich foams had a higher degree of polymerization than the latter,foam the relatively mild heat treatment.The gluten foams were promising as insulation materials. The thermal conductivityvalues were 0.04-0.05 (W/m⋅°C), and were close to that of commercially available closed cellpolystyrene and polyurethane foams, that both have values at ca. 0.03 (W/m⋅°C).The wheat gluten foams showed also promising combustion properties with longignition times, no material dripping and a large content of residual char. The glycerolcontainingfoam however, exhibited a more rigorous bubbling and a larger flame.

  • 275.
    Blomfeldt, Thomas O. J.
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Kuktaite, R.
    Plivelic, T. S.
    Rasheed, F.
    Johansson, E.
    Hedenqvist, Mikael S.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Novel freeze-dried foams from glutenin- and gliadin-rich fractions2012In: RSC Advances, ISSN 2046-2069, Vol. 2, no 16, p. 6617-6627Article in journal (Refereed)
    Abstract [en]

    This is the first study on freeze-dried foams prepared from glutenin- and gliadin-rich fractions of wheat gluten and blends thereof. It was found that the foam density and stiffness could be controlled by a suitable choice of the glutenin/gliadin ratio. The glutenin-rich samples had the highest foam densities and the density decreased with increasing gliadin content. The compression modulus also decreased with increasing gliadin content, which was explained by the decrease in foam density, a more open porosity and the more aggregated/polymerized structure in the presence of glutenin. IR and SE-HPLC revealed that the least aggregated foams were those consisting only of the gliadin-rich fraction. Confocal laser scanning microscopy revealed the presence of both HMW-glutenin and gliadin (to a certain extent probably resisting the ethanol extraction process) in the glutenin-rich foams. SAXS indicated that the gliadin-rich fraction contributed with weakly correlated protein aggregates with a characteristic distance of 40-43 Å.

  • 276.
    Bodell, Linnéa
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH).
    Investigation of Factors Affecting the Emulsification of Skin Creams2019Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Skin creams are one of Sky Resources key products, they are produced as an oil-in-water(O/W) emulsion. In order to form an emulsion the oil and water needs to be able to mixtogether, for that to happen the oil and water droplets have to be broken up into very smalldroplets (colloids).

    There is a certain quality difference between the products from the research and developmentdepartment and the production department.

    The skin creams have been made through a given recipe, which contains a number of chemicalformulas. Tests have been preformed and the results have been examined. The creams werefirst made in the research and development department’s laboratory and then that small scaleproduction was taken to big scale production in the production department. The results havebeen documented and the parameters that have been examined are speed, temperature and timeto see how they affect the viscosity of the creams.

    A factorial experiment with three factors has been made. The factors are the time the skincream is homogenized, at what speed the cream is homogenized and at what temperature thephases are when the homogenizing is started. That gives a total of 8 creams from thelaboratory level.

    The viscosity of the skin creams have been measured after 10 minutes, 24 hours, 48 hours and1 week to see how it is increasing with time and if it is increasing at all or perhaps decreasing.After 1 week the creams were also studied under a microscope to see how successful theemulsions were with different factors.

    The fourth cream was the only cream from the laboratory that had a successful emulsion andstabilized viscosity. So the factors that are brought from laboratory to production is highhomogenization time, high homogenization speed and low temperature. Two differenthomogenizers were tried in production.

    The factor that affects the viscosity the most seems to be the temperature. After these tests,there is still a difference between the products from the research and development departmentand the production department even with the lower temperatures on the oil and water phases.The second cream from production and cream 4 from the laboratory show the smallest qualitydifference. More tests need to be done in the production department with differenthomogenization speed and time with the lower temperature to establish the result.

  • 277.
    Bodén, Andreas
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    The anode and the electrolyte in the MCFC2007Doctoral thesis, comprehensive summary (Other scientific)
    Abstract [en]

    A goal of the Swedish government is to increase the usage of renewable fuels and biomass-based fuels. Fuel cells, and especially the MCFC, are useful for these types of fuels. The Swedish market may benefit from the MCFC in two ways: increased efficiency of the biofuels and also utilisation of produced heat in district heating. Most of the commercial MCFC systems today are optimised for use with methane. The possibility to utilise biomass in Sweden makes it important to study how the MCFC may be adapted or optimised for good performance and low degradation with gas produced from biomass or other renewable fuels.

    This thesis is focused on methods that may be used to investigate and evaluate MCFC electrodes and electrolytes with renewable fuels i.e. CO2-containing gases. The methods and results are both experimental and mathematically modelled. The objectives of this thesis are to better understand how the performance of the anode is dependent on different fuels. Anode kinetics and the water-gas shift reaction have been investigated as well as the possibility to increase cell lifetime by increasing the initial electrolyte amount by having the anode as a reservoir. The effect of segregation of cations in the electrolyte during operation has also been studied.

    It was found that if the gas composition at the current collector inlet is in equilibrium according to the water gas-shift reaction the gas composition inside the electrode is almost uniform. However, if the gas is not in equilibrium then the concentration gradients inside the current collector have a large effect on the gas composition inside the electrode. The conversion of the gas in the gas flow channels according to the water-gas shift reaction depends on the gas flow rate. For an anode used in a gas mixture of humidified hydrogen and carbon dioxide that are not in equilibrium some solubility of Ni in a (Li/Na)2CO3 mixture was found. To have the anode act as an electrolyte reservoir to prolong cell lifetime the anode pore size should be carefully matched with that of the cathode and a bimodal pore-size distribution for the anode is preferable to have as good performance as possible for as large electrolyte filling degree interval as possible. Modelling results of segregation of cations in the electrolyte during operation indicate that the electrolyte composition changes during operation and that the lithium ions are enriched at the anode for both types of electrolyte used for the MCFC. The electrolyte composition changes are small but might have to be considered in long-time operation. The results from this thesis may be used to better understand how the MCFC may be used for operation with renewable fuels and how electrodes may be designed to prolong cell lifetime.

  • 278.
    Bodén, Andreas
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Di, Jing
    School of Chemical Engineering and Technology, Tianjin University, China.
    Lagergren, Carina
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Lindbergh, Göran
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Wang, Cheng Yang
    School of Chemical Engineering and Technology, Tianjin University, China.
    Conductivity of SDC and (Li/Na)2CO3 composite electrolytes in reducing and oxidising atmospheres2007In: Journal of Power Sources, ISSN 0378-7753, E-ISSN 1873-2755, Vol. 172, no 2, p. 520-529Article in journal (Refereed)
    Abstract [en]

    Composite electrolytes made of samarium-doped cerium oxide and a mixture of lithium carbonate and sodium carbonate salts are investigated with respect to their structure, morphology and ionic conductivity. The composite electrolytes are considered promising for use in so called intermediate temperature solid oxide fuel cells (IT-SOFC), operating at 400-600 degrees C. The electrolytes are tested in both gaseous anode (reducing) and cathode (oxidising) environments and at different humidities and carbon dioxide partial pressures. For the structure and morphology measurements, it was concluded that no changes occur to the materials after usage. From measurements of melting energies, it was concluded that the melting point of the carbonate salt phase decreases with decreasing fraction of carbonate salt and that a partial melting occurs before the bulk melting point of the salt is reached. For all the composites, two regions may be observed for the conductivity, one below the carbonate salt melting point and one above the melting point. The conductivity is higher when electrolytes are tested in anode gas than when tested in cathode gas, at least for electrolytes with less than half the volume fraction consisting of carbonate salt. The higher the content of carbonate salt phase, the higher the conductivity of the composite for the temperature region above the carbonate melting point. Below the melting point, though, the conductivity does not follow this trend. Calculations on activation energies for the conductivity show no trend or value that indicates a certain transport mechanism for ion transport, either when changing between the different composites or between different gas environments.

  • 279.
    Bodén, Andreas
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Lindbergh, Göran
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    A Model for Mass Transport of Molten Alkali Carbonate Mixtures Applied to the MCFC2006In: Journal of the Electrochemical Society, ISSN 0013-4651, E-ISSN 1945-7111, Vol. 153, no 11, p. A2111-A2119Article in journal (Refereed)
    Abstract [en]

    A one-dimensional model based on the Stefan-Maxwell formulation for mass transfer of the main components of a binary molten carbonate electrolyte, including all of the nonidealities, was formulated and applied to the molten carbonate fuel cell (MCFC). The Stefan-Maxwell diffusion coefficients were determined from literature transport data; still, a narrow parameter window in electrolyte composition and temperature had to be used to keep the integrity of the fits. The model for calculation of the electrolyte composition was combined with equations describing the current distribution in the electrodes and the electrolyte. The calculated results of the electrolyte composition changes show that they depend predominantly on the current density and the total electrolyte filling degree. It was also concluded that the electrolyte composition changes are less then two percent for Li/K and five percent for Li/Na. This model demonstrates how experimental data measured at equilibrium conditions may be used to determine Stefan-Maxwell diffusion coefficients and then applied to a transport model for the electrolyte, in this case an MCFC.

  • 280.
    Bodén, Andreas
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Yoshikawa, Masahiro
    Central Research Institute of Electric Power Industry, Energy Conversion Engineering Sector, Kanagawa Japan.
    Lindbergh, Göran
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Influence of the anode pore-size distribution and total electrolyte filling degree on the MCFC performance2008In: Journal of the Electrochemical Society, ISSN 0013-4651, E-ISSN 1945-7111, Vol. 155, no 2, p. B172-B179Article in journal (Other academic)
    Abstract [en]

    Experimental data of the total cell reaction resistance as a function of the total electrolyte filling degree was measured to investigate how more electrolyte initially may be added to get as long a cell lifetime as possible. The reaction resistance of each electrode was also measured using two gas compositions and various total electrolyte filling degrees. A theoretical model for the distribution of electrolyte between the anode and the cathode as a function of the total electrolyte filling degree was used to compare the experimental data in this study with data from a symmetrical cell setup. The model takes into account the electrode pore-size distributions and considers two cases for the contact angle between the electrode and the electrolyte for the anode: a zero wetting angle (fully wetted) or reported experimental values for the wetting angle on pure Ni. It was concluded that after the cathode initially has been sufficiently filled with electrolyte the anode pores have to be smaller than the remaining ones of the cathode to allow having the anode act as a reservoir to prolong cell lifetime. The results from the experimental data and the theoretical model for electrolyte distribution were compared with results from a symmetrical setup.

  • 281.
    Bodén, Andreas
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Yoshikawa, Masahiro
    Central Research Institute of Electric Power Industry, Energy Engineering Research Laboratory, Kanagawa ,Japan.
    Lindbergh, Göran
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    The solubility of Ni in molten Li2CO3–Na2CO3 (52/48) in H2/H2O/CO2 atmosphere2007In: Journal of Power Sources, ISSN 0378-7753, E-ISSN 1873-2755, Vol. 166, no 1, p. 59-63Article in journal (Refereed)
    Abstract [en]

    In this work the solubility of a Ni-Al anode for MCFC has been studied at atmospheric pressure and two different temperatures using various gas compositions containing H-2/H2O/CO2. It is well known that nickel is dissolved at cathode conditions in an MCFC. However, the results in this study show that nickel can be dissolved also at the anode, indicating that the solubility increases with increasing CO2 partial pressure of the inlet gas and decreasing with increasing temperature. This agrees with the results found by other authors concerning the solubility of NiO at cathode conditions. The dissolution of Ni into the melt can proceed in two ways, either by the reduction of water or by the reduction of carbon dioxide.

  • 282. Bohlin, M.
    et al.
    Rasmuson, Åke Christoffer
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering.
    Application of controlled cooling and seeding in batch crystallization1992In: The Canadian Journal of Chemical Engineering, Vol. 70, no 1, p. 120-126Article in journal (Refereed)
  • 283. Bohlin, M.
    et al.
    Rasmuson, Åke Christoffer
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering.
    Importance of Macromixing in Batch Cooling Crystallization1996In: AIChE Journal, Vol. 42, no 3, p. 691-699Article in journal (Refereed)
  • 284. Bohlin, M.
    et al.
    Rasmuson, Åke Christoffer
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering.
    Modeling of growth rate dispersion in batch cooling crystallization1992In: AIChE Journal, Vol. 38, no 12, p. 1853-1863Article in journal (Refereed)
  • 285.
    Bojler Görling, Martin
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    Energy system evaluation of thermo-chemical biofuel production: Process development by integration of power cycles and sustainable electricity2012Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Fossil fuels dominate the world energy supply today and the transport sector is no exception. Renewable alternatives must therefore be introduced to replace fossil fuels and their emissions, without sacrificing our standard of living. There is a good potential for biofuels but process improvements are essential, to ensure efficient use of a limited amount of biomass and better compete with fossil alternatives. The general aim of this research is therefore to investigate how to improve efficiency in biofuel production by process development and co-generation of heat and electricity. The work has been divided into three parts; power cycles in biofuel production, methane production via pyrolysis and biofuels from renewable electricity.

    The studies of bio-based methanol plants showed that steam power generation has a key role in the large-scale biofuel production process. However, a large portion of the steam from the recovered reaction heat is needed in the fuel production process. One measure to increase steam power generation, evaluated in this thesis, is to lower the steam demand by humidification of the gasification agent. Pinch analysis indicated synergies from gas turbine integration and our studies concluded that the electrical efficiency for natural gas fired gas turbines amounts to 56-58%, in the same range as for large combined cycle plants. The use of the off-gas from the biofuel production is also a potential integration option but difficult for modern high-efficient gas turbines. Furthermore, gasification with oxygen and extensive syngas cleaning might be too energy-consuming for efficient power generation.

    Methane production via pyrolysis showed improved efficiency compared with the competing route via gasification. The total biomass to methane efficiency, including additional biomass to fulfil the power demand, was calculated to 73-74%. The process benefits from lower thermal losses and less reaction heat when syngas is avoided as an intermediate step and can handle high-alkali fuels such as annual crops.

    Several synergies were discovered when integrating conventional biofuel production with addition of hydrogen. Introducing hydrogen would also greatly increase the biofuel production potential for regions with limited biomass resources. It was also concluded that methane produced from electrolysis of water could be economically feasible if the product was priced in parity with petrol.

  • 286.
    Bolakhrif, Sabah
    KTH, School of Chemical Science and Engineering (CHE).
    Synthesis and application of PLA and PLA/GO fibers through thermo-responsive transformation of PLA particles2016Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    PLA nanofibers were successively produced by thermo-responsive transformation of PLA particles in water. The morphological structure of the nanofibers could be optimized by the heat treatment as well as the incorporation of GO to the fiber surface. PLA/GO fiber demonstrated a more stable morphology and GO provided good compatibility between PLA and starch. Both PLA and PLA/GO fibers incorporated in starch films resulted in increased thermal stability and mechanical properties. However, the most favorable properties were assigned starch films containing high concentration of PLA/GO fibers. These films with completely green components could possibly be utilized in biodegradable packaging applications.

                                                                                                                               

  • 287.
    Bondesson, Laban
    KTH, School of Biotechnology (BIO), Theoretical Chemistry.
    Microscopic Interpretations of Drug Solubility2007Doctoral thesis, comprehensive summary (Other scientific)
  • 288.
    Bondesson, Laban
    et al.
    KTH, School of Biotechnology (BIO), Theoretical Chemistry.
    Frediani, Luca
    Department of Chemistry, University of Tromsø, Norway.
    Ågren, Hans
    KTH, School of Biotechnology (BIO), Theoretical Chemistry.
    Mennucci, Bendetta
    Dipartimento di Chimica e Chimica Industriale, Università di Pisa, Italy.
    Solvation of N3- at the water surface: the Polarizable Continuum Model approach2006In: Journal of Physical Chemistry B, ISSN 1520-6106, E-ISSN 1520-5207, Vol. 110, no 23, p. 11361-11368Article in journal (Refereed)
    Abstract [en]

    We present a new quantum mechanical model to introduce Pauli repulsion interaction between a molecular solute and the surrounding solvent in the framework of the Polarizable Continuum Model. The new expression is derived in a way to allow naturally for a position-dependent solvent density. This development makes it possible to employ the derived expression for the calculation of molecular properties at the interface between two different dielectrics. The new formulation has been tested on the azide anion (N-3(-)) for which we have calculated the solvation energy, the dipole moment, and the static polarizability at the interface as a function of the ion position. The calculations have been carried out for different ion-surface orientations, and the results have also been compared with the parallel electrostatic-only solvation model.

  • 289.
    Bondesson, Laban
    et al.
    KTH, School of Biotechnology (BIO), Theoretical Chemistry.
    Hugosson, H. W.
    Calculations of the cavitation volumes and partial molar volumes of drugs in waterManuscript (preprint) (Other academic)
  • 290.
    Bondesson, Laban
    et al.
    KTH, School of Biotechnology (BIO), Theoretical Chemistry.
    Mikkelsen, Kurt V.
    Department of Chemistry, University of Copenhagen.
    Luo, Yi
    KTH, School of Biotechnology (BIO), Theoretical Chemistry.
    Garberg, Per
    Biovitrum AB, Stockholm.
    Ågren, Hans
    KTH, School of Biotechnology (BIO), Theoretical Chemistry.
    Density functional theory calculations of hydrogen bonding energies of drug molecules2006In: Journal of Molecular Structure, ISSN 0022-2860, E-ISSN 1872-8014, Vol. 776, no 1-3, p. 61-68Article in journal (Refereed)
    Abstract [en]

    Hydrogen bonding energies of several drug molecules have been calculated using hybrid density functional theory with inclusion of basis set superposition error corrections. The calculated total hydrogen bonding energy of each drug molecule has been compared with the result of a conceptually simple additive model, from which the summation of hydrogen bonding energies of individual polar groups present in the drug molecule are considered. It is shown that the validity of the additive model is strongly conditional, and to some extent predictable: In cases where the hydrogen bonding group is isolated the addition model can be of relevance, while in cases where the hydrogen bonding groups are interconnected through pi-conjugation rings or chains of the drug molecules it introduces substantial errors. It is suggested that such strong cooperative effects of hydrogen bonds should always be taken into account for evaluation of the hydrogen bonding energies of drug molecules.

  • 291.
    Bondesson, Laban
    et al.
    KTH, School of Biotechnology (BIO), Theoretical Chemistry.
    Mikkelsen, Kurt V.
    Department of Chemistry, University of Copenhagen.
    Luo, Yi
    KTH, School of Biotechnology (BIO), Theoretical Chemistry.
    Garberg, Per
    Biovitrum AB, Stockholm.
    Ågren, Hans
    KTH, School of Biotechnology (BIO), Theoretical Chemistry.
    Hydrogen bonding effects on infrared and Raman spectra of drug molecules2007In: Spectrochimica Acta Part A - Molecular and Biomolecular Spectroscopy, ISSN 1386-1425, E-ISSN 1873-3557, Vol. 66, no 2, p. 213-224Article in journal (Refereed)
    Abstract [en]

    Infrared and Raman spectra of three drug molecules, aspirin, caffeine and ibuprofen, in gas phase and in aqueous solution have been simulated using hybrid density functional theory. The long range solvent effect is modelled by the polarizable continuum model, while the short range hydrogen bonding effects are taken care of by the super-molecular approach with explicit inclusion of water molecules. The calculated spectra are found to compare well with available experimental results. The agreement obtained make grounds for proposing theoretical modeling as a tool for characterizing changes in the bonding environments of drug molecules in terms of particular variations in their IR and Raman spectra.

  • 292.
    Bondesson, Laban
    et al.
    KTH, School of Biotechnology (BIO), Theoretical Chemistry (closed 20110512).
    Rudberg, Elias
    KTH, School of Biotechnology (BIO), Theoretical Chemistry (closed 20110512).
    Luo, Yi
    KTH, School of Biotechnology (BIO), Theoretical Chemistry (closed 20110512).
    Salek, Pawel
    KTH, School of Biotechnology (BIO), Theoretical Chemistry (closed 20110512).
    A linear scaling study of solvent-solute interaction energy of drug molecules in aqua solution2007In: Journal of Physical Chemistry B, ISSN 1520-6106, E-ISSN 1520-5207, Vol. 111, no 34, p. 10320-10328Article in journal (Refereed)
    Abstract [en]

    Solvent-solute interaction energies for three well-known drug molecules in water solution are computed at the Hartree-Fock and B3LYP density functional theory levels using a linear scaling technique, which allows one to explicitly include in the model water molecules up to 14 A away from the solute molecule. The dependence of calculated interaction energies on the amount of included solvent has been examined. It is found that it is necessary to account for water molecules within an 8 A radius around the drug molecule to reach the saturated solvent interaction level. Effects of electron correlation and basis set on solvent-solute interaction energies are discussed.

  • 293. Bonvin, D.
    et al.
    Georgakis, C.
    Pantelides, C. C.
    Barolo, M.
    Grover, M. A.
    Rodrigues, D.
    Schneider, R.
    Dochain, D.
    Linking Models and Experiments2016In: Industrial and Engineering Chemistry Research, Vol. 55, no 25, p. 6891-6903Article in journal (Refereed)
  • 294.
    BOOG RUDBERG, SUSANN
    KTH, School of Chemical Science and Engineering (CHE).
    Kylanläggning för småskalig ölproduktion anpassad för jäsning och lagring av lageröl2015Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    There has been a large increase of microbreweries in Sweden in the past few years, most of which produce great beers such as ales and stouts. This is however a bit strange since most Swedes seem to prefer to drink lager; at least if you study the statistics of the Swedish alcohol monopoly’s top hundred most drunken beers last year. There might be several reasons for microbreweries not brewing lagers but one reason is the equipment needed for lager brewing. Apart from the regular brewing equipment needed for brewing ales, a cooling system is needed in lager brewing in order to reach the ideal temperatures for fermentation, 10°°C, and lagering. Lagering is a process where beer is stored for weeks or months in a cold place, typically around 0°C.  The cooling systems on the market are expensive and small start-up microbreweries do not have the funds to purchase these. One example of such a microbrewery is Brewing Költur, and this study aims to solve the cooling problem for them.

    The goal was to design a cheaper alternative for cooling a 300-litre batch of beer but without severe changes in quality. The product needs to be able to hold stable temperatures and also lower the temperatures from 10°°C to 0°°C, both without major fluctuations in temperature within the vessel. The project did not aim at solving other lager brewing related problems.

    The result was a Bag-in-Box: a chest freezer in which a disposable plastic bag, big enough to fit 300 litres of beer, was placed. An air gap was created in between the inside walls of the freezer and the bag to keep the sudden cold walls from damaging the yeast by cooling it to quickly.

    A prototype was put together in order to test the most important features of the product. The tests showed that the product could keep stable temperatures very well in the lower temperature intervals, while it needed manual stirring in the higher regions to avoid temperature gradients, especially when the temperature was lowered.

    The cost of the product is overall very low. The investment cost is very low, however since the disposable bags are somewhat costly the variable cost is fairly high, yet still significantly cheaper than the alternatives on the market.

    It is believed that the product could be used by many smaller microbreweries in the future due to the low investment cost, its ability to keep the temperatures relatively stable and also because it is easy to assemble.

     

  • 295.
    Bor, Yasemin
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Alin, Jonas
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymer Technology.
    Hakkarainen, Minna
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymer Technology.
    Polylactide stereocomplexation leads to reduced migration during microwave heating in contact with food simulants2014In: Journal of Food Engineering, ISSN 0260-8774, E-ISSN 1873-5770, Vol. 134, p. 1-4Article in journal (Refereed)
    Abstract [en]

    The effect of stereocomplexation on the stability and migration resistance of polylactide during microwave and conventional heating in contact with different food simulants was evaluated. The heating effects were followed through mass loss measurements, molecular weight measurements and identification of the individual migrants by electrospray ionization-mass spectrometry (ESI-MS). Increased mass losses were observed as a function of time and temperature, but approximately 50% smaller mass losses were always measured for PLA stereocomplex as compared to the corresponding regular PLEA material. The stability of the stereocomplex material was, thus, significantly higher. Microwave heating increased the mass loss as compared to the conventional heating at the same time and temperature. This effect was especially significant when 10% ethanol was used as food simulant instead of water. The amount of water-soluble migrants was in most cases under the detection limits, but when heating temperature was increased to 95 C, ESI-MS revealed the formation of homologous series of linear lactic acid oligomers. Results indicate that PEA stereocomplex materials could have potential in single-use microwave applications.

  • 296.
    BORIS ERIC ALAIN, BIZET
    KTH, School of Chemical Science and Engineering (CHE).
    From Sugar to Furfural Compounds Using Flow Chemistry2015Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Due to the need to find alternatives for the current fossil-based chemical industry, the use of blo-sourced platform chemicals as building blocks for the synthesis of a wide range of industrial and consumer chemicals has gained significantly in importance over the past years.

    In this context, 5-(chloromethyl)furfural (CMF) could become a very interesting target for  the implementation of a sugar-based biorefinery. Originating from the dehydration of cellulose,  hemlcellulose or sugar, it can for example be a precursor of bio-fuels and/or fuel additives. However, there are very few published examples on the CMF synthesis as well as its ability to be further converted in interesting derivatives.

    A simple procedure for the conversion of sugar-based feedstocks to CMF, using flow chemistry, is reported in this  master  thesis.  Sucrose  and  High  Fructose  Corn  Syrup  (HFCS-90  and  HFCS-55)  were  shown  to  be suitable feedstocks. The use of HFCS-90 has been demonstrated to be particularly promising, as it could be converted in a stable process which yields 70% of CMF.

    As a proof of concept, condensation reactions of 5-methylfurfural (MF) and CMF were performed with amine compounds, thus expanding the existing pool of CMF derivatives. MF condensations could be performed under harsh conditions, whereas CMF required milder treatments. Very high conversions were observed, especially when using aliphatic amines as starting materials.

  • 297.
    Bors, Peter
    KTH, School of Chemical Science and Engineering (CHE).
    Dagvattenundersökning på Falu Återvinning2012Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    In 2011, Falu Återvinning laid out 5 500 m2 of new tarmac to be used as storage space, mostly for digested sludge composting. In a correlation with this the County Administrative Board of Dalarna gave an investigation condition. This condition meant that the storm water at Falu Återvinning was to be examined in regards of pollution concentrations, masses, flows and possible environmental impact on the surroundings. The condition also meant that an appropriate treatment of the storm water was to be suggested. Today, the majority of the storm water is lead to an existing leachate pond while the remaining storm water goes to the Stångtjärnsbäck, which is a stream with a certain protection value since it contains fish.

    This report will serve as a basis for future expansion of the Self-monitoring program for Water at Falu Återvinning in regards of storm water. Self-monitoring means that businesses that can cause harm to human and/or environmental health have an obligation to monitor this impact.

    The purpose of the thesis project was to plan and carry out a sample-taking of the storm water at Falu Återvinning, and evaluate the results of the analyzes. These results were to be used as the basis of choosing appropriate treatment of the storm water.

    Prior to sampling, different sampling methods and the extent of the analyze were investigated. The sampling methods included grab and composite samples as well as passive sampling devices. The advantages and disadvantages of the different sampling methods as well as the conditions at Falu Återvinning formed the basis for the choice of method. The extent of the analyzes were chosen so that this included nutrient salts, heavy metals, organic parameters and a number of environmental pollutants. Which environmental pollutants were to be examined was chosen by consideration to the waste that is treated at Falu Återvinning.

    The acquired results were evaluated and used as a base for the recommendation of appropriate treatment of storm water at Falu Återvinning. An economical solution was desired so simple and/or natural treatment processes were investigated, since these are cheaper to run and requires less advanced technology. Processes that were investigated were storm water ponds, grassed areas, detention basins and the possibility to send the storm water to the local wastewater treatment facility, Främby Avloppsreningsverk.

    The investigated storm water at Falu Återvinning showed high concentrations of foremost nutrient salts, zinc and organic material. The sampling point of DV5 indicated that penetrated ground water may have been polluted by leachate from a nearby landfill. This is due to very high concentrations of organic material, alkalinity, chloride and ammonia nitrogen. Especially the very high concentrations of ammonia nitrogen and chloride indicated a pollution of leachate.

    The storm water in the sampling point DV1 showed elevated concentrations of cadmium, copper, zinc and organic materials. The highest concentrations of sulfate were found in this sampling point, although these values were lower than the guideline value of sulfate in drinking water. Concentrations of PCB were detected in DV1. DV3 contained high concentrations of lead, organic materials and nutrient salts, but the storm water in this point is collected and sent to the leachate pond. The composition of DV4 was the most varying out of all the sampling points, but showed high concentrations of organic materials, nitrogen and copper.

    The stormwater in sampling points DV1 and DV4 should not be lead to the Stångtjärnsbäck. The best treatment options for the storm water at Falu Återvinning would either be a storm water pond or the ability to send the water to the wastewater treatment facility Främby Avloppsreningsverk.

  • 298. Bose, Indranil
    et al.
    Ohlander, Anna
    Stich, Matthias I. J.
    Kiesl, Christian
    Hemmetzberger, Dieter
    Klink, Gerhard
    Trupp, Sabine
    Bock, Karlheinz
    Polymer opto-chemical-electronic based module as a detection system for volatile analytes on a foil substrate2012In: Proceedings of SPIE - The International Society for Optical Engineering, SPIE - International Society for Optical Engineering, 2012, Vol. 8479Conference paper (Other academic)
    Abstract [en]

    In this paper, we report on a novel device that addresses the needs for an efficient, field deployable and disposable system in the field of bio-chemical sensors using organic semiconductors. The Fraunhofer Institute has enabled a complete roll-to-roll manufactured polymer-opto-chemical-electronic module on a foil substrate, wherein an electroluminescent light source has been hetero-integrated together with an organic TFT, working as a photo detector. A chemically sensitive, colour changing film is sandwiched in between the two elements to form an optical detection system for volatile analytes such as amines. The setup, henceforth referred to as the “PolyOpto” module, comprises of a dye coated layer that can detect specific chemical reactions by colour change inserted in between the EL light source and the OTFT photo-detector. A hole is laser cut through the system to allow the sensor layer to come in contact with the gases, which then through a chemical reaction, changes colour and initiates a different response in the output of the organic transistor. Hence, this allows for a disposable chemo-analytical system that can be used in various application fields. As compared to conventional systems, the advantage here lies in the direct integration of the different functionalities without any advanced assembly steps, simultaneous use of coatings for both components (transparent electrode and wiring layer) and roll-to-roll compatibility, thus rendering a disposable system. We believe that it aptly demonstrates the capabilities of polytronics in functional integration for low-cost bio-sensor manufacturing

  • 299. Bostrom, Dan
    et al.
    Grimm, Alejandro
    Boman, Christoffer
    Björnbom, Emilia
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Ohman, Marcus
    Influence of Kaolin and Calcite Additives on Ash Transformations in Small-Scale Combustion of Oat2009In: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 23, p. 5184-5190Article in journal (Refereed)
    Abstract [en]

    A growing interest has been observed for the use of cereal grains in small- and medium-scale heating. Previous studies have been performed to determine the fuel quality of various cereal grains for combustion purposes. The present investigation was undertaken in order to elucidate the potential abatement of low-temperature corrosion and deposits formation by using fuel additives (calcite and kaolin) during combustion of oat. Special emphasis was put on understanding the role of slag and bottom ash composition on the volatilization of species responsible for fouling and emission of fine particles and acid gases. The ash fractions were analyzed with scanning electron micro scopy/energy dispersive spectroscopy (SEM/EDS), for elemental composition, and with X-ray diffraction (XRD) for identification of crystalline phases. The previously reported K and Si capturing effects of kaolin additive were observed also in the present study using P-rich biomass fuels. That is, the prerequisites for the formation of low melting K-rich silicates were reduced. The result of using kaolin additive on the bottom ash was that no slag was formed. The effect of the kaolin additive on the formation of submicrometer flue gas particles was an increased share of condensed K-phosphates at the expense of K-sulfate and KCl. The latter phase was almost completely absent in the particulate matter. Consequently, the levels of HCl and SO2 in the flue gases increased somewhat. The addition of both calcite assortments increased the amount of farmed slag, although to a considerably higher extent for the precipitated calcite. P was captured to a higher degree in the bottom ash, compared to the combustion of pure oat. The effect of the calcite additives on the fine particle emissions in the flue gases was that the share of K-phosphate decreased considerably, while the content of K-sulfate and KCl increased. Consequently, also the flue-gas levels of acidic HCl and SO2 decreased. This implies that the low-temperature corrosion observed in small-scale combustion of oat possibly can be abated by employing calcite additives. Alternatively, if problems with slagging and deposition of corrosive matter at heat convection surfaces are to be avoided, kaolin additive can be utilized, on the condition that the higher concentrations of acidic gases can be tolerated.

  • 300.
    Boström, Fanny
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH).
    Experimental testing of adsorbents for H2S removal in industrial applications: A comparative study on lifetime and cost effectiveness of different materials2019Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Harmful emissions are a global issue and cause trouble for human health and for the environment. There is a wide variety of pollutants and one pollutant is hydrogen sulfide, H2S, that is a member of the group Volatile Sulfur Compounds. H2S is a compound that is known for its smell of rotten eggs and is detectable by the human nose at very low concentrations. At higher concentrations, H2S is highly toxic and even deadly for humans. It is also a corrosive gas, and can, therefore, cause problems for materials that are being exposed to it. This can be an issue when H2S is present in biogas since it can damage engines or pipes. It can also poison catalysts that are used for methane upgrading.

    There are different methods of removing H2S from air and common ones are to use adsorption media or catalytic oxidation for gas-solid reactions. The catalytic oxidation is oxidizing the H2S and converts it into elemental sulfur. A problem with these techniques is that they need replacement after some time when they have been saturated.

    The aim and objectives for this project are to find appropriate materials to test in a test rig that was finalized at the beginning of the project, to compare their lifetime. This was done to find the most cost effective material for H2S removal. The effect of humidity in the air was also examined.

    Eight different samples were tested. Two of these were activated carbonwithout impregnations and the other six were partial catalytic materials (impregnated carbons or metal oxide based materials). The partial catalytic materials were significantly better than the activated carbons. The lifetimes varied among the partial catalytic materials as well, andare believed to be due to different active compounds on the surfacesand the structure. When running the experiments with 70 % relative humidity, the lifetimes were significantly longer than when the same materials were run for 30 %. A lower concentration of H2S in low relative humidity showed lower or the same loading capacity than higher concentrations. Regeneration was tested for one of the metal based materials with a satisfactory result.

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