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  • 1.
    Ahlström, Peter
    et al.
    University of Borås, School of Engineering.
    Aim, Karel
    Dohrn, Ralf
    Elliott, J Richard
    Jackson, George
    Jaubert, Jean Noël
    Rebello de A. Macedo, Maria Eugénia
    Pokki, Juha-Pekka
    Reczey, Kati
    Victorov, Alexey
    Fele Zilnik, Ljudmila
    Economou, Ioannis
    A Survey of the Role of Thermodynamics and Transport Properties in ChE University Education in Europe and the USA2010In: Chemical Engineering Education, ISSN 0009-2479, Vol. 44, no 1, p. 35-43Article in journal (Refereed)
    Abstract [en]

    Thermodynamics and Transport Properties (TTP) is a central subject in the majority of chemical engineering curricula worldwide and it is thus of interest to know how it is taught today in various countries if chemical engineering education is to be improved. A survey of graduate thermodynamics education in the USA was performed a few years ago by Visco et al. [1] but as far as we know no systematic study of the undergraduate thermodynamics education has been performed, at least in recent years. In the present study, a survey about TTP education in Europe and the USA is presented. Results were obtained from nearly twenty different European countries and the USA and in total answers from about 150 universities were used for this study. The study is performed under the auspices of the Working Party of Thermodynamics and Transport Properties of the European Federation of Chemical Engineering. The survey was performed using a web based surveying system for which invitations were sent out to the universities by local representatives who were responsible for one or more countries each. Of the universities that answered more than 70 % offer BSc education 65 % offer MSc education and 55 % offer PhD education. Most universities offer at least two courses of thermodynamics. The following discussion is mainly based on the first two (undergraduate) courses reported. Half of these are taught to chemical engineers exclusively whereas the rest are taught with other branches of engineering, mainly mechanical and / or process engineering. In general two sets of course lengths were observed, corresponding either to a full semester of full time studies or to quarter of a semester. Most courses are centered around lectures and exercise classes with little or no laboratory work whereas home assignments are given in the vast majority (70-80 %) of the courses. The first course is mainly centered around the first and second law of thermodynamics whereas the second course is frequently more concentrated on phase equilibria. Both of these courses are mainly comprising of classical thermodynamics whereas the molecular interpretation often is touched upon. An analysis of the differences between thermodynamics education in Europe and the USA in presently being undertaken and results from this will also be presented. An investigation of the use of thermodynamics within industry is also on-going within the Working Party and results will be reported in the near future. [1] S.K.Dube, D.P. Visco, Chem. Eng. Ed., 2005, 258-263.

  • 2.
    Ahlström, Peter
    et al.
    University of Borås, School of Engineering.
    Moodley, Suren
    University of Borås, School of Engineering.
    Bolton, Kim
    University of Borås, School of Engineering.
    Ramjugernath, D.
    University of Borås, School of Engineering.
    Computer Simulations of Vapor-Liquid-Liquid Equilibria Involving Hydrocarbons and Water2008In: Proceedings of the 100th Annual Meeting of the American Institute for Chemical Engineering, 2008, CHPC National Meeting, Durban, South Africa, December 9-10, 2008, AlChe Annual Meeting, Philadelphia, November 15-21, 2008, 2008Conference paper (Other academic)
  • 3.
    Eliasson, Anna
    University of Borås, Faculty of Textiles, Engineering and Business.
    En studie av egenskaperna hos biokol som adsorberande agent i o‐DGTanordningar2017Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    A new complex aspect in the matter of water quality is the occurrence of emerging organicpollutants and contaminants in waste water. The currently low extent to which treatment ofwaste water is performed in Brazil, and in the world as a whole, there is a considerable needfor development of cheap and accurate in‐situ sampling methods for far‐reaching studies ofsurface water quality. The lack of such methods today makes the maintenance andestablishing of sanitary safety difficult. This diploma work gives a brief introduction to thebasic principles of the passive sampling method known as Diffusive Gradient in Thin‐films(DGT). A method that could be useful for such monitoring of quality in water bodies worldwide.The aim of this study is to develop a method, for the detection of organic emerging pollutantsand contaminants – i.e. compounds, which usually are present at very low concentrationswhen found in the environment as a result of human activity. More specifically, this workinvestigates the potential and usefulness of the application of DGT devices in detection oforganic compounds that can affect human health and ecosystems, even at lowconcentrations, however, their effects still are in need of further investigations.This study focuses on both purely technical as well as practical points of views. The efficiencyof organic DGT (o‐DGT) with biochar as the adsorbing agent is examined targeting thedetection of organic pollutants and contaminants in surface water. In this sense, the specificaim of the work is to evaluate the performance of biochar as adsorbing agent. This workshowed that the performance of biochar as the adsorbing agent in binding layers in o‐DGTsample devices can be considered as satisfactory since all compounds of interest in this studywas successfully detected, quantified an identified. Further investigations in the future areneeded to determine the effects of varying pH, temperature and ion concentration in thedeployment media, as well as the properties of the binding layer in relation to concentrationof biochar and the thickness of the layer. These in order to optimize the method for in‐situwater sampling, aiming conventional use of biochar as the adsorbing agent in the future.

  • 4.
    Erdtman, Edvin
    et al.
    University of Borås, School of Engineering.
    Gebäck, Tobias
    University of Borås, School of Engineering.
    Ahlström, Peter
    University of Borås, School of Engineering.
    Atomistic Modelling of Protein Superabsorbents2012Conference paper (Other academic)
  • 5. George, Gejo
    et al.
    Tomlal Jose, E.
    Åkesson, Dan
    University of Borås, School of Engineering.
    Skrifvars, Mikael
    University of Borås, School of Engineering.
    Nagarajan, E.R.
    Kuruvilla, Joseph
    Viscoelastic behaviour of novel commingled biocomposites based on polypropylene/jute yarns2012In: Composites. Part A, Applied science and manufacturing, ISSN 1359-835X, E-ISSN 1878-5840, Vol. 43, no 6, p. 893-902Article in journal (Refereed)
    Abstract [en]

    Jute yarn reinforced polypropylene commingled composites were prepared by an environmentally benign technique called commingling method in which the matrix fibres and reinforcing fibres are intermingled together with good alignment. The dynamic mechanical properties or viscoelastic behaviour of these commingled composites were studied with reference to fibre content and various chemical treatments. The storage and loss modulus increased with fibre content where as tan δ decreased. KMnO4 and MAPP treated composites showed much higher storage and loss modulus values at all temperatures compared to untreated one. The glass transition temperature showed a marginal increasing tendency with fibre content and chemical treatments. The surface treatment mechanisms were supported by FT-IR spectra and the increase in interfacial adhesion after chemical treatments were supported by SEM images. Theoretical modelling was used to predict the values of storage modulus and tan δ and was found to be comparable with that of experimentally obtained results.

  • 6.
    Jeihanipour, Azam
    University of Borås, School of Engineering.
    Waste Textiles Bioprocessing to Ethanol and Biogas2011Doctoral thesis, monograph (Other academic)
    Abstract [en]

    The work of the present thesis focused on conversion of the cellulosic part of waste textiles into biogas and ethanol, and its challenges. In 2009, the global annual fiber consumption exceeded 70 Mt, of which around 40% consisted of cellulosic material. This huge amount of fibers is processed into apparel, home textiles, and industrial products, ending up as waste after a certain time delay. Regretfully, current management of waste textiles mainly comprises incineration and landfilling, in spite of the potential of cellulosic material being used in the production of ethanol or methane. The volume of cellulose mentioned above would be sufficient for producing around 20 billion liters of ethanol or 11.6 billion Nm3 of methane per year. Nevertheless, waste textiles are not yet accepted as a suitable substrate for biofuel production, since their processing to biofuel presents certain challenges, e.g. high crystallinity of cotton cellulose, presence of dyes, reagents and other materials, and being textiles as a mixture of natural and synthetic fibers. High crystallinity of cotton cellulose curbs high efficient conversion by enzymatic or bacterial hydrolysis, and the presence of non-cellulosic fibers may create several processing problems. The work of the present thesis centered on these challenges. Cotton linter and blue jeans waste textiles, all practically pure cellulose, were converted to ethanol by SSSF, using S. cerevisiae, with a yield of about 0.14 g ethanol/g textile, only 25% of the theoretical yield. To improve the yield, a pretreatment process was required and thus, several methods were examined. Alkaline pretreatments significantly improved the yield of hydrolysis and subsequent ethanol production, the most effective condition being treatment with a 12% NaOH-solution at 0 °C, increasing the yield to 0.48 g ethanol/g textile (85% of the theoretical yield). Waste textile streams, however, are mixtures of different fibers, and a separation of the cellulosic fibers from synthetic fibers is thus necessary. The separation was not achieved using an alkaline pretreatment, and hence another approach was investigated, viz. pretreatment with N-methyl-morpholine-N-oxide (NMMO), an industrially available and environment friendly cellulose solvent. The dissolution process was performed under different conditions in terms of solvent concentration, temperature, and duration. Pretreatment with 85% NMMO at 120 °C under atmospheric pressure for 2.5 hours, improved the ethanol yield by 150%, compared to the yield of untreated cellulose. This pretreatment proved to be of major advantage, as it provided a method for dissolving and then recovering the cellulose. Using this method as a foundation, a novel process was developed, refined and verified, by testing polyester/cellulose-blended textiles, which predominate waste textiles. The polyesters were purified as fibers after the NMMO treatments, and up to 95% of the cellulose content was regenerated. The solvent was then recovered, recycled, and reused. Furthermore, investigating the effect of this treatment on anaerobic digestion of cellulose disclosed a remarkable enhancement of the microbial solubilization; the rate in pretreated textiles was twice the rate in untreated material. The overall yield of methane was, however, not significantly affected. The process developed in the present thesis appears promising for transformation of waste textiles into a suitable raw material, to subsequently be used for biological conversion to ethanol and biogas.

  • 7. Mattsson, Tuve
    et al.
    Richards, Tobias
    University of Borås, School of Engineering.
    The separation of green liquor sludge: A comparison between liquors produced in a gasifier and a recovery boiler2009Conference paper (Other academic)
    Abstract [en]

    Green liquor is produced as when chemicals are recovered in the kraft pulp process. The industrial formed green liquor contains a solid, non-solvable phase, called green liquor dregs and are removed either by filtration, or by sedimentation. This work compares separation properties of green liquor produced in a gasifier unit with green liquor produced in a recovery boiler. The two types of green liquors were found to have almost similar separation properties with respect to both sedimentation and filtration. For filtration, the average specific filtration resistance was about 1012 m/kg at 1 bar filtration pressure.

  • 8.
    Mohsenzadeh, Abas
    et al.
    University of Borås, Faculty of Textiles, Engineering and Business.
    Richards, Tobias
    University of Borås, Faculty of Textiles, Engineering and Business.
    Bolton, Kim
    University of Borås, Faculty of Textiles, Engineering and Business.
    DFT study of the water gas shift reaction on Ni (111), Ni (100) and Ni (110) surfaces2016In: Surface Science, ISSN 0039-6028, E-ISSN 1879-2758, Vol. 644, p. 53-63Article in journal (Refereed)
    Abstract [en]

    Density functional theory (DFT) calculations were used to study the water gas shift (WGS) reaction on Ni(111), Ni(100) and Ni(110) surfaces. The adsorption energy for ten species involved in thereaction together with activation barriers and reaction energies for the nine most important elementary steps were determined using the same model and DFT methods. The results reveal that these energies are sensitive to the surface structure. In spite of this, the WGS reaction occurs mainly via the direct (also referred to as redox) pathway with the CO + O → CO2 reaction as the rate determining step on all three surfaces. The activation barrier obtained for this rate limiting step decreases in the order Ni(110) > Ni(111) > Ni(100). Therefore, if O species are present on the surfaces then the WGSreaction is fastest on the Ni(100) surface. However, the barrier for desorption of H2O (which is the source of the O species) is lower than its dissociation reaction on the Ni(111) and Ni(100) surfaces, but not on the Ni(110) surface. Hence, at low H2O(g) pressures, the direct pathway on the Ni(110) surface will dominate and will be the rate limiting step. The calculations also show that the reason that the WGS reaction does not primarily occur via the formate pathway is that this species is a stable intermediate on all surfaces. The reactions studied here support the Brønsted-Evans-Polanyi (BEP) principles with an R2 value of 0.99. © 2015 Elsevier B.V. All rights reserved.

  • 9.
    Olsson, Johanna
    et al.
    University of Borås, School of Engineering.
    Pallarés, David
    Johnsson, Filip
    Digital Image Analysis of Bubble Flow Distribution: Influence of operational parameters2010Conference paper (Refereed)
    Abstract [en]

    In a first step towards investigating the lateral fuel mixing in fluidized bed (FB) boilers, this work applies digital image analysis to study the bubble flow properties in a 2D FB unit. The work investigates the influence of gas-distributor pressure drop, bed height and fluidization velocity on the volume fraction and lateral distribution of bubbles.

  • 10.
    Osadolor, Osagie Alex
    et al.
    University of Borås, Faculty of Textiles, Engineering and Business.
    Lundin, Magnus
    University of Borås, Faculty of Textiles, Engineering and Business.
    Lennartsson, Patrik
    University of Borås, Faculty of Textiles, Engineering and Business.
    Taherzadeh, Mohammad
    University of Borås, Faculty of Textiles, Engineering and Business.
    Membrane stress analysis of collapsible tanks andbioreactorsIn: Biochemical engineering journal, ISSN 1369-703X, E-ISSN 1873-295XArticle in journal (Refereed)
    Abstract [en]

    Collapsible tanks, vessels or bioreactors are finding increasing usage in small/medium scaleprocesses because they offer flexibility and lower cost. However, if they are to be used atlarge scale, they need to be shown capable of handling the physical stress exerted on them.Because of their nonconventional shape and non-uniform pressure distribution, thin shellanalysis cannot be used in calculating their stress. Defining curvature in terms of pressureaddressed these challenges. Using curvature and numerical analysis, the membrane stress incollapsible tanks designed as bioreactors of volumes between 100-1000 m3 were calculated.When the liquid/gas height and static pressure are known, an equation for calculating tensionper length was developed. An equation that could calculate the liquid height from thebioreactor’s volume, dimensions and working capacity was generated. The equation gavevalues of liquid height with a maximum deviation of 3% from that calculated by curvatureanalysis. The stress values from the liquid height and tension equations had a maximumdeviation of 6% from those calculated by curvature analysis. The calculated tensile stress in a1000 m3 collapsible tank was 14.2 MPa. From these calculations, materials that optimize bothcost and safety can be selected when designing collapsible tanks.

    The full text will be freely available from 2018-06-23 08:23
  • 11.
    Richards, Tobias
    University of Borås, Faculty of Textiles, Engineering and Business.
    Thermal pretreatment of black liquor: A conceptual design2017Conference paper (Refereed)
    Abstract [en]

    The recovery boiler is a vital part of the chemical recovery cycle and should produce a smelt of the cooking chemicals together with steam at high temperature and pressure. Part of these chemicals are found in the gases, either as small fume particles or as gases and this could cause problems such as deposits, corrosion and material losses. A thermal pre-treatment method is proposed to minimize the sodium and sulfur in the upper region of the boiler. Sulfur is released at temperatures below 600 °C in reducing atmospheres but most of this is recaptured by the black liquor droplets. The sodium losses are mostly by fume formation during char burning but a part could also be by physical ejection which would release sulfur as well.

  • 12.
    Richards, Tobias
    et al.
    University of Borås, School of Engineering.
    Neretnieks, Ivars
    Filtering of clay colloids in MX-80 detritus material2009Conference paper (Other academic)
    Abstract [en]

    Bentonite clay consists of two types of materials; the small nanoscale smectite particles and the larger accessory material particles. When used as a barrier, it is important that no material is lost. This might occur if water with low salinity is passing by the bentonite clay. First, the clay will first swell and then the smectite particles can be solubilised. This work investigates under which circumstances the material can form a filter cake of the accessory material and slow down or stop the penetration of smectite through the filter cake. We have showed that it is possible to form such a filter cake and that the filter cake can be further improved by adding other particles.

  • 13. Richards, Tobias
    et al.
    Theliander, Hans
    White liquor production: A comparison of the causticizing stages using gasifier and recovery boiler produced green liquor2010Conference paper (Refereed)
    Abstract [en]

    Green liquor, starting with sludge removal and ending with white liquor separation, has been investigated from a recovery boiler and a state-of-the-art gasification unit using the same black liquor for the two processes. This has been possible due to the co-location of a demonstration-sized pressurized gasification unit and a recovery boiler. Tests were performed under varying conditions in the gasifier while the conditions in the recovery boiler were assumed constant. Our investigation shows that the separation properties of green liquor sludge after a gasifier are almost similar to the separation properties after a recovery boiler. It is clear that the total load of reburned lime mud increases in the case of a gasifier, but the total concentration of the produced white liquor equals mill demand (i.e. is the same as recovery boiler produced white liquor). It was also found that causticizing efficiency was not affected by the increased load of reburned lime mud and the changed composition in the gasifier produced green liquor. Therefore, it can be concluded that the formation of sodium hydroxide in the white liquor produced from an entrained flow gasifier will not be limited by the existing process technology.

  • 14.
    Rosén, Karl G
    University of Borås, School of Engineering.
    In-cabin air quality: electrostatic field to capture sub-micron size particles2014Conference paper (Refereed)
    Abstract [en]

    Traffic is regarded as the main reason for the air pollution problem and it seems obvious to try to reduce the particulate bioload affecting those travelling. Recently Volvo Cars introduced their Interior Air Quality System forcing the cabin air to be recirculated in case of a high level of noxious gases shutting out carbon monoxide, ground-level ozone and nitrogen dioxide. Ionization is another component of Mercedes AIR-BALANCE package. Considering the fact that it is the nano-size ultra-fine particles (UFP) that are known to cause the “oxidative” stress of the immune system one may ask if even the most well designed HEPA filter would sufficiently affect the in-cabin air particulates or is there a need for additional means by which the sub-micron class particles may be captured. An electrostatic field of sufficient strength may serve as an additional tool to clean the cabin air from sub-micron size particles.The initial data from the study indicate that electrostatic mechanisms substantially add to the in-cabin air cleaning properties of ultra-fine particulates compared to the standard filtering technology when recirculating the cabin air.

  • 15.
    Souza Filho, Pedro
    et al.
    University of Borås, Faculty of Textiles, Engineering and Business.
    Zamani, Akram
    University of Borås, Faculty of Textiles, Engineering and Business.
    Taherzadeh, Mohammad J
    University of Borås, Faculty of Textiles, Engineering and Business.
    Solid Precipitation from Potato Protein Liquor by Ethanol2015Conference paper (Refereed)
    Abstract [en]

    The production of starch in European Union (EU 28) was around 10 million tonnes in 2013, 12.6% of them being from potato1. During the potato processing, two main by-products which have high Biological Oxygen Demand (BOD) are formed, i.e. potato pulp (PP) and potato liquor (PL)2. Proteins can be partially recovered from PL, resulting in a concentrated residual material known as potato protein liquor (PoPL)2,3. The use of PoPL has been investigated to cultivate fungal4 and yeast3 biomass, and produce enzymes2. However, presence of nitrogen and phosphate containing materials as well as suspended solids at high concentrations4 limits its application in bioprocesses. The present study was proposed to investigate the precipitation of components from PoPL by ethanol in order to get an easily fermentable solution. PoPL from Lyckeby Starch AB was mixed with different amounts of ethanol and centrifuged at 3000 g for 5 min. The liquid obtained was put under a fume hood for 48 h at room temperature for ethanol evaporation. All the samples had their volumes adjusted to the same value using distilled water. The precipitate was dried at 105 °C. All experiments were done in duplicate. The precipitation of solids improved almost 500% for a mixture of equal volumes of PoPL and ethanol compared to PoPL without ethanol addition. The protein and ash contents of the precipitate were respectively higher than 245 g/kg and 420 g/kg in all the cases, making it eligible for production of fertilizer or animal feed. Most of the analysed sugars (glucose, fructose, and sucrose) stayed in the liquid phase. Ethanol concentration in the liquid phase remained close to initial value after the 48-hour evaporation. This indicates the need for a distillation column for ethanol recovery before the remaining sugar solution can be used for fermentation purposes.

  • 16.
    Åkesson, Dan
    et al.
    University of Borås, School of Engineering.
    Foltynowicz, Zenon
    Christéen, Jonas
    Skrifvars, Mikael
    University of Borås, School of Engineering.
    Microwave pyrolysis as a method of recycling glass fibre from used blades of wind turbines2012In: Journal of reinforced plastics and composites (Print), ISSN 0731-6844, E-ISSN 1530-7964, Vol. 31, no 17, p. 1136-1142Article in journal (Refereed)
    Abstract [en]

    The possibility of recycling glass fibre-reinforced composites by using microwave pyrolysis was examined. A scrap blade from a wind turbine was fragmented and microwave-pyrolysed. The glass fibre recovered after pyrolysis represented 70% of the initial mass of glass fibre-reinforced composites. The tensile strength of the glass fibre recovered was measured after pyrolysis and compared to the tensile strength of untreated glass fibre. The test showed that the fibres lost about 25% of their tenacity. Non-woven fibre mats were prepared from the recovered fibres. Laminates were then prepared from the non-woven mats obtained, together with virgin glass fibre mats. Mechanical testing of the laminates showed that it is possible to prepare composites using 25 wt% of recycled fibres, with relatively good mechanical properties.

  • 17.
    Åkesson, Dan
    et al.
    University of Borås, School of Engineering.
    Skrifvars, Mikael
    University of Borås, School of Engineering.
    Recycling of glass fibre reinforce plastics using microwave pyrolysis2012Conference paper (Other academic)
1 - 17 of 17
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