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  • 1.
    Afroz, Laila
    et al.
    Clean Energy Research Laboratory (CERL), Department of Physics, COMSATS University Islamabad, Lahore Campus, Lahore 54000, Pakistan.
    Rafaqat, Muhammad
    Clean Energy Research Laboratory (CERL), Department of Physics, COMSATS University Islamabad, Lahore Campus, Lahore 54000, Pakistan;Centre of Excellence in Solid State Physics, University of the Punjab, Lahore 54590, Pakistan.
    Ahmad, M. Ashfaq
    Clean Energy Research Laboratory (CERL), Department of Physics, COMSATS University Islamabad, Lahore Campus, Lahore 54000, Pakistan.
    Bashir, Tariq
    University of Borås, Faculty of Textiles, Engineering and Business.
    Naqvi, Muhammad
    College of Engineering and Technology, American University of the Middle East, Egaila, Kuwait 54200, Kuwait.
    Abbas, Ghazanfar
    Clean Energy Research Laboratory (CERL), Department of Physics, COMSATS University Islamabad, Lahore Campus, Lahore 54000, Pakistan.
    Mustafa, Ghulam M
    Department of Physics, Division of Science and Technology, University of Education, Lahore, Punjab 54770, Pakistan.
    Raza, Rizwan
    Clean Energy Research Laboratory (CERL), Department of Physics, COMSATS University Islamabad, Lahore Campus, Lahore 54000, Pakistan.
    Nanocomposite Catalyst (1 – x)NiO-xCuO/yGDC for Biogas Fueled Solid Oxide Fuel Cells2023In: ACS Applied Energy Materials, E-ISSN 2574-0962, Vol. 6, no 21, p. 10918-10928Article in journal (Refereed)
    Abstract [en]

    The composites of Ni–Cu oxides with gadolinium doped ceria (GDC) are emerging as highly proficient anode catalysts, owing to their remarkable performance for solid oxide fuel cells operated with biogas. In this context, the nanocomposite catalysts (1 – x)NiO-xCuO/yGDC (x = 0.2–0.8; y = 1,1.3) are synthesized using a solid-state reaction route. The cubic and monoclinic structures are observed for NiO and CuO phases, respectively, while CeO2 showed cubic fluorite structure. The scanning electron microscopic images revealed a rise in the particle size with an increase in the copper and GDC concentration. The optical band gap values are calculated in the range 2.82–2.33 eV from UV–visible analysis. The Raman spectra confirmed the presence of vibration modes of CeO2 and NiO. The electrical conductivity of the nanocomposite anodes is increased as the concentration of copper and GDC increased and reached at 9.48 S cm–1 for 0.2NiO-0.8CuO/1.3GDC composition at 650 °C. The electrochemical performance of (1 – x)NiO-xCuO/yGDC (x = 0.2–0.8; y = 1,1.3)-based fuel cells is investigated with biogas fuel at 650 °C. Among all of the as-synthesized anodes, the fuel cell with composition 0.2NiO-0.8CuO/1.3GDC showed the best performance, such as an open circuit voltage of 0.84 V and peak power density of 72 mW cm–2. However, from these findings, it can be inferred that among all other compositions, the 0.2NiO-0.8CuO/1.3GDC anode is a superior combination for the high electrochemical performance of solid oxide fuel cells fueled with biogas.

  • 2.
    Ahl, Victor
    et al.
    University of Borås, Faculty of Textiles, Engineering and Business.
    Henriksson, Erik
    University of Borås, Faculty of Textiles, Engineering and Business.
    Energianalys och förslag på energieffektivisering: Nohabgatan 11, Trollhättan2018Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    In this report an energy analysis of a brick building housing mostly office- and workshop businesses. The energy analysis contained a heating balance and an electricity balance. The result of these balances was the basis for a couple of suggestions of interventions for energy efficiency. The purpose was to make an energy analysis regarding heating and cooling demand as well as electricity usage for a building in Trollhättan and also give propositions of interventions for energy efficiency. With a starting-point in drawings of the building and also collected data for bought district heating (?) and electricity for 2017, a heating balance and an electricity balance was set up. From these balances calculations were made to give a perspicuous picture over what the heat and electricity is used for in the building. The heating losses consisted of transmission-, ventilation-, infiltration- and drainage pipe losses. The input of heat consisted of bought district heating, solar radiation, internal heat from electrical devices and persons in the building as well as heat losses from hot water pipes and water heater that contributed to the heating. The electricity usage largely consisted of lighting, computers with accessories, kitchen equipment, ventilation system, pumps, cooling system and servers. The bought district heating was 863 823 kWh and the bought electricity was 482 395 kWh, whereof 119 179 kWh was calculated to be useful heat for the building. Solar radiation was calculated to contribute to the heating with 35 249 kWh. Of losses, transmission was the larger item with 822 747 kWh followed by infiltration losses of 131 258 kWh and ventilation losses of 77 418 kWh. Drainage pipe losses as well as input heating through heat losses from hot water pipes and water heater was small in the context. The results of the calculations showed that the building had an energy performance of 130 kWh/(m2, year) and an electricity usage of 21 kWh/(m2, year).Energy saving interventions that was proposed was for instance additional insulation, change of lighting, overlooking the operation of ventilation- and heating system, change of pumps, installing solar cells and Demand Controlled Ventilation.

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    fulltext
  • 3.
    Awasthi, Mukesh Kumar
    et al.
    College of Natural Resources and Environment, Northwest A&F University, Shaanxi Province, Yangling, 712100, China.
    Amobonye, Ayodeji
    Department of Biotechnology and Food Science, Faculty of Applied Sciences, Durban University of Technology, P O Box 1334, Durban, 4000, South Africa.
    Bhagwat, Prashant
    Department of Biotechnology and Food Science, Faculty of Applied Sciences, Durban University of Technology, P O Box 1334, Durban, 4000, South Africa.
    Ashokkumar, Veeramuthu
    Center for Waste Management and Renewable Energy, Saveetha Dental College and Hospitals, Saveetha Institute of Medical and Technical Sciences, Saveetha University, Chennai, 600077, India.
    Gowd, Sarath C.
    Department of Environmental Science and Engineering, School of Engineering and Sciences, SRM University, Andhra Pradesh, India.
    Dregulo, Andrei Mikhailovich
    National Research University “Higher School of Economics”, 17 Promyshlennaya str, Saint-Petersburg, 198095, Russian Federation.
    Rajendran, Karthik
    National Research University “Higher School of Economics”, 17 Promyshlennaya str, Saint-Petersburg, 198095, Russian Federation.
    Flora, G.
    Department of Botany, St. Mary's College (Autonomous), Tamil Nadu, India.
    Kumar, Vinay
    Bioconversion and Tissue Engineering (BITE) Laboratory, Department of Community Medicine, Saveetha Medical College and Hospital, Saveetha Institute of Medical and Technical Sciences (SIMATS), Thandalam, Chennai, 602105, India.
    Pillai, Santhosh
    Department of Biotechnology and Food Science, Faculty of Applied Sciences, Durban University of Technology, P O Box 1334, Durban, 4000, South Africa.
    Zhang, Zengqiang
    College of Natural Resources and Environment, Northwest A&F University, Shaanxi Province, Yangling, 712100, China.
    Sindhu, Raveendran
    Department of Food Technology, TKM Institute of Technology, Kerala, Kollam, 691 505, India.
    Taherzadeh, Mohammad J
    University of Borås, Faculty of Textiles, Engineering and Business.
    Biochemical engineering for elemental sulfur from flue gases through multi-enzymatic based approaches – A review2024In: Science of the Total Environment, ISSN 0048-9697, E-ISSN 1879-1026, Vol. 914, article id 169857Article, review/survey (Refereed)
    Abstract [en]

    Flue gases are the gases which are produced from industries related to chemical manufacturing, petrol refineries, power plants and ore processing plants. Along with other pollutants, sulfur present in the flue gas is detrimental to the environment. Therefore, environmentalists are concerned about its removal and recovery of resources from flue gases due to its activation ability in the atmosphere to transform into toxic substances. This review is aimed at a critical assessment of the techniques developed for resource recovery from flue gases. The manuscript discusses various bioreactors used in resource recovery such as hollow fibre membrane reactor, rotating biological contractor, sequential batch reactor, fluidized bed reactor, entrapped cell bioreactor and hybrid reactors. In conclusion, this manuscript provides a comprehensive analysis of the potential of thermotolerant and thermophilic microbes in sulfur removal. Additionally, it evaluates the efficacy of a multi-enzyme engineered bioreactor in this process. Furthermore, the study introduces a groundbreaking sustainable model for elemental sulfur recovery, offering promising prospects for environmentally-friendly and economically viable sulfur removal techniques in various industrial applications. 

  • 4.
    Björklund, Anders
    et al.
    University of Borås, Faculty of Textiles, Engineering and Business.
    Ahmad, Muhammad
    University of Borås, Faculty of Textiles, Engineering and Business.
    Reläskyddsberäkningar för fördelningsstationen Ålgården2018Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This project has been undertaken to establish new setting values for the relay protection systems for the distribution station Ålgården. Since a new distribution station is about to be put into operation which will be used to supply parts of the electrical network that is currently supplied by Ålgården has made it necessary to review the set values of the safety systems. The final result of the project is the selectivity plan that has been established. To achieve this, detailed calculations have been made of the electrical distribution network, including shortcircuit calculations and calculations of overloads. This report describes the characteristics ofthe electrical distribution network, the transformers in it, and the current measuring relayprotection systems for the distribution station Ålgården, short circuit theory as well as theresults of the calculations.

  • 5.
    Burrows, Michel
    University of Borås, Faculty of Textiles, Engineering and Business.
    Projektering och energieffektivisering av värme- och ventilationssystem för ett flerbostadshus vid Vänern2021Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    A property with several apartments located in the small village of Otterbäcken in Gullspång municipality has burned down. The property will be rebuilt in accordance with Boverket buildings rules BBR and the requirements that are relevant for 2021.The diploma project has been a collaboration between the University of Borås and the consulting company Energi Triangeln AB located in the city of Gothenburg. As part of the project a re-design of the heating and ventilation system of the property will be carried out using two different simulation programs used when designing buildings. The first program is MagiCad from the company Autodesk. In this program drawings are made of the building including the drawings of the heating and ventilation systems. The second program is more focused at energy balances and energy efficiency calculation of the property. You get the energy performance of the property. The translated name is “Heat balances in a duration diagram”. The program is developed by a consulting company connected to Chalmers University of Technology named “Chalmers Industrial Technology”, CIT.

    The original technical solution for the ventilation in the building before it burned down was a system not using any fans. When rebuilding the house, the design of the ventilation system includes the comparison of two modern system both using extraction fans for forcing spent air to leave the building. The first alternative uses both a supply fan and exhaust fan with a heat exchanger for heat recovery of the heat in the exhaust ventilation duct. This system is used together with a heat pump taking heat from the ground. The second technical solution of ventilation system uses an exhaust fan in connection to a heat pump. That is a system where the heat recovery of the heat in the exhaust duct is recovered in the heat pump instead of extracting heat from the ground as in alternative one. Alternative two has no centralized intake of ventilation air, instead fresh air is coming into the apartments below windows in the sleeping rooms and living room of the apartments through individual ducts.

    By using the program energy performance program “BV2”, two different cases were calculated and expressed in specific energy consumption of both electricity and heat using the unit kWh/m2, per year. This means that the property which was designed with both an exhaust and a supply fan (and heat exchanger) for ventilation of the building and for the design with an exhaust air fan only but using a heat pump for heat recovery from the exhaust air, these two cases can be compared. To be able to carry out this project, it was necessary, among other things there was a need to access proper building drawings of the property that is being built and projected.

    The purpose and main objectives of the project are fulfilled.

    Furthermore, as a continuation of the course called “Computed Aided Design, (CAD), for buildings, the design of secondary heating, domestic hot and cold water and sewage water was carried out using MagiCad. The method used to carry out this project was to use the drawings of the building, measure the area of the shell, windows, doors, roofs and floor of the building and by using the second simulation program BV2 to be able to calculate the energy required of the building.

    The result of the degree project states that the choice of a geothermal heat pump with a heat exchanger for heat recovery between the exhaust duct and the duct with incoming fresh air provides the best alternative from an energy performance perspective. You consume fewer kilowatt hours to be able to cover the heating demand in the building. If you choose a geothermal heat pump with a heat recovery using only a heat exchanger the saving in purchased electricity to be able to satisfy the property´s energy demand is approximately 12 527 kWh/ electricity annually. which with a common electricity price in Sweden, (of 1.19 crowns/kWh) provides approximately 14 900 Swedish crowns per year in savings of purchased electricity for heat production.

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    Projektering och energieffektivisering av värme- och ventilationssystem för ett flerbostadshus vid Vänern
  • 6.
    Carlsson, Linus
    et al.
    University of Borås, Faculty of Textiles, Engineering and Business.
    Ragnarsson, Niklas
    University of Borås, Faculty of Textiles, Engineering and Business.
    Energibalansberäkning för nybyggnad: Identifiering av avvikelser från primärenergiberäkning för flerbostadshus2021Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Gräshoppan 13 is an apartment building located in Borås. The property has been followed up by energy consulting company Aktea AB on behalf of the property owner Willhem in order to environmentally certify the building as GreenBuilding. The primary calculation performed by Isover showed that the property was expected to consume 34 kWh/m2, year. Akteas follow-up after two years resulted in the property consuming 45.2kWh/m2, year, which does not enable certification according to GreenBuilding where the requirements are 41.3kWh/m2, year, that is 25 % lower than the requirements from Boverkets building regulations, BBR.

    The following report discusses and analyzes the possible sources of error as to why the estimated energy consumption performed by Isover is not met. The system solution for domestic hot water, which has been assumed by Akteas energy consultant Jonas Pettersson to be the most contributing factor, is mainly examined. This is because Isover calculated the energy consumption for domestic hot water to be 6kWh/m2, year when the actual outcome resulted in an energy consumption of 18.2kWh/m2, year.

    A control calculation of Isover energy balance calculation was made, however without full access to Isovers calculations input. The calculation gave a similar result (Isover 34kWh/m2, year, control calculation 35kWh/m2, year). This was done to exclude errors in Isovers energy balance calculation and to strengthen Akteas assumptions regarding the system solution for the domestic hot water.

    A pressure test in one of the apartments in the property was carried out to check, which can be an indicator of, the construction quality of the property. The test printing showed that the property maintains a good air tightness (0.23 l/sm2) and does not negatively affect the property's energy consumption. This test also confirms Akteas assumption that there are no energy losses due to leaks.

    The system solution for the domestic hot water required more energy than calculated because the accumulator tank in the system proved difficult to maintain an even temperature. This means that a water heater with an immersion heater needs to work harder for the domestic hot water to keep BBR's requirements at 55 ℃. Why the accumulator tank has difficulty maintaining an even temperature is believed to be that the volume is too small and is affected too much by large water drains in the property. The fact that the heat pump is not optimally set can also be a contributing factor.

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    Energibalansberäkning för nybyggnad – Identifiering av avvikelser från primärenergiberäkning för flerbostadshus
  • 7.
    Claesson, Frida
    et al.
    University of Borås, School of Engineering.
    Skrifvars, B-J
    Elled, Anna-Lena
    University of Borås, School of Engineering.
    Johansson, A
    Chemical characterization of waste fuel for fluidized bed combustion2009Conference paper (Refereed)
    Abstract [en]

    Combustible waste is very heterogeneous and the variation in chemical composition is of great significance for the performance of the combustors in terms of boiler availability and power efficiency. For example, the content of alkali, Chlorine and sulfur affect agglomeration, fouling and corrosion mechanisms, which often limits the steam data and requires counteracts such as soot blowing and outages. An increased knowledge on favorable levels and ratios of fuel components are therefore highly important when developing waste combustors, both existing and future. However, to be able to make good predictions of reactions, reliable fuel analyses are a necessity and they are difficult to perform because of the heterogeneity of waste. As a consequence, it is also difficult to complete pro-active measure to reduce unwanted reactions. This work has investigated the composition of the fuel during one year in a 40 MW commercial BFB waste plant. Twelve samples have been performed in order to estimate the variation of key components. The fuel samples were analyzed chemically for alkali and several other components of interest, such as Cl and S. Moreover, thermo-chemical multi-phase equilibrium calculations were performed for prediction of the chemical composition of the furnace in the temperature range 400-1000 ºC. In this temperature range NaCl and PbClx are formed as well as gas phase HCl and solid silicates. Furthermore, the calculations show that the chemistry is very sensitive to the input chemical composition, suggesting that already a minor shift in fuel mineral matter may change the behavior of the fuel radically in terms of its fouling and corrosion tendency.

  • 8.
    Dahlby, Mikael
    et al.
    University of Borås, Faculty of Textiles, Engineering and Business.
    Gustafson Sjöberg, Robin
    University of Borås, Faculty of Textiles, Engineering and Business.
    Studie av ventilation i simhall: Med fokus på klorbaserade luftföroreningar2017Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Public baths contributes significantly to the promotion of public health and wellbeing. To be able to supply a pleasant experience for bathers, a high quality of water and air is required. To avoid spreading of pathogens between bathers, Chlorine is used as a central component for disinfecting the water. Chlorine residues such as Trichloramine affect human health and are concentrated above the water surface and will remain in the breathing zone unless the pollution is carried away by air movement.Nolhaga public bath is undergoing a renovation and this report is a study of the new ventilation system which has been installed. To investigate the air flow pattern in the hall a CAD model of the space was created. CFD software was used to simulate airflow in the model. Results have also been compared with a smoke test, performed in a similar building. In addition to the suggested solution a different approach, with additional exhaust air vents placed at floor level, has been tested.The results show that the air speeds over the water surface are within the given recommendations. The air has a tendency to move around in the room with a recirculating behaviour where the supply air follows the roof to the back wall and then returns over the surface of the water. This kind of behaviour might be beneficial for removing Trichloramines if exhaust air vents are placed near the air supply units. This method uses the air movement to remove pollutants where the concentration is highest and removes them from the building. Performed smoke test gave only vague indications that the simulation results can be linked to actual air movement due to the small amount of information it provided.Due to the lack of time, knowledge and experience in the field, the uncertainty of the achieved results is great. Additional work in CFD and ventilation of public baths is required to enhance credibility of results.

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  • 9. Davidsson, K.O.
    et al.
    Åmand, L.-E.
    Elled, A.-L.
    University of Borås, School of Engineering.
    Leckner, B.
    Effect of Cofiring Coal and Biofuel with sewage Sludge on Alkali Problems in a Circulating Fluidized Bed Boilder2007In: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 21, no 6, p. 3180-3188Article in journal (Refereed)
    Abstract [en]

    Cofiring experiments were performed in a 12 MW circulating fluidized bed boiler. The fuel combinations were biofuel (wood+straw), coal+biofuel, coal+sewage sludge+biofuel, and sewage sludge+biofuel. Limestone or chlorine (PVC) was added in separate experiments. Effects of feed composition on bed ash and fly ash were examined. The composition of flue gas was measured, including on-line measurement of alkali chlorides. Deposits were collected on a probe simulating a superheater tube. It was found that the fuel combination, as well as addition of limestone, has little effect on the alkali fraction in bed ash, while chlorine decreases the alkali fraction in bed ash. Sewage sludge practically eliminates alkali chlorides in flue gas and deposits. Addition of enough limestone to coal and sludge for elimination of the SO2 emission does not change the effect of chlorine. Chlorine addition increases the alkali chloride in flue gas, but no chlorine was found in the deposits with sewage sludge as a cofuel. Cofiring of coal and biofuel lowers the alkali chloride concentration in the flue gas to about a third compared with that of pure biofuel. This is not affected by addition of lime or chlorine. It is concluded that aluminum compounds in coal and sludge are more important than sulfur to reduce the level of KCl in flue gas and deposits.

  • 10. Davidsson, K.O.
    et al.
    Åmand, L.-E.
    Steenari, B.-M.
    Elled, A.-L.
    University of Borås, School of Engineering.
    Eskilsson, D.
    Leckner, B.
    Countermeasures against alkali-related problems during combustion of biomass in a circulating fluidized bed boiler2008In: Chemical Engineering Science, ISSN 0009-2509, E-ISSN 1873-4405, Vol. 63, no 21, p. 5314-5329Article in journal (Refereed)
    Abstract [en]

    The purpose of this work was to study different ways to mitigate alkali-related problems during combustion of biomass in circulating fluidized beds. Wood chips and wood pellets were fired together with straw pellets, while the tendency to agglomerate and form deposits was monitored. In addition to a reference case, a number of countermeasures were applied in related tests. Those were addition of elemental sulphur, ammonium sulphate and kaolin to a bed of silica sand, as well as use of olivine sand and blast-furnace slag as alternative bed materials. The agglomeration temperature, composition and structure of bed-ash samples were examined. The flue-gas composition, including gaseous alkali chlorides, was measured in the hot flue gases and in the stack. Particles in the flue gas were collected and analysed for size distribution and composition. Deposits were collected on a probe in hot flue gases and their amount and composition were analysed. Addition of kaolin was found to be the best method to counteract the agglomeration problem. The deposition problem is effectively counteracted with addition of ammonium sulphate, while kaolin is too expensive to be used commercially against deposits, and sulphur is less effective than ammonium sulphate.

  • 11.
    Dessne, Petter
    et al.
    University of Borås, School of Business and IT.
    Fachina, Vicente
    University of Borås, School of Business and IT.
    Golmen, Lars G.
    University of Borås, School of Business and IT.
    Miller, Alan K.
    University of Borås, School of Business and IT.
    Panchal, C. B.
    University of Borås, School of Business and IT.
    Hammar, Linus
    University of Borås, School of Business and IT.
    Jamaluei, Zahra Yadali
    University of Borås, School of Business and IT.
    Duckers, Les
    University of Borås, School of Business and IT.
    Blanchard, Richard
    University of Borås, School of Business and IT.
    Banerjee, Subhashish
    University of Borås, School of Business and IT.
    Baird, Jim
    University of Borås, School of Business and IT.
    Johnson, Ted
    University of Borås, School of Business and IT.
    Bharathan, Desikan
    University of Borås, School of Business and IT.
    Lever, Harold
    University of Borås, School of Business and IT.
    Yu, Jason C. S.
    University of Borås, School of Business and IT.
    Chen, W.
    University of Borås, School of Business and IT.
    OTEC matters 20152015Report (Other academic)
    Abstract [en]

    For mankind as a whole, and in many respects, the world is becoming a better place each year. In both rich and poor countries the standard of living has improved steadily for a very long time. This progress has a serious drawback, the negative effects on Earth’s climate. It is clear that the only way we can live sustainably is by consuming much less. However, this is not enough: there is an undeniable need for new energy sources. As the world’s population grows, many countries will also face more severe shortages of food and of fresh, disease-free water. Most developing countries are situated in tropical regions and are therefore hit hard by increasing tropical storms and similar weather-based disasters, adding to these problems. Ocean Thermal Energy Conversion (OTEC) technology has been proven to be an ideal candidate for addressing and resolving all of these problems for small island developing states (SIDS), and a few months ago, the EU set aside€72 million euros for constructing OTEC plants outside Martinique. Built on a much larger scale, OTEC can, as the only technology known to man, supply the world with its total energy and fresh water needs, increase seafood production many times over, and cooling off parts of the sea surface when they become too hot – all this without any atmospheric emissions. Thus, it is with great excitement that this very first issue of the only journal dedicated to OTEC is being published. The publication covers many facets of OTEC and related matters, such as OTEC technology, sustainability including gender and other social studies, renewable energy, marine biology, metallurgy, and research on developing countries. The publication is aimed at two different audiences, scientists directly or indirectly involved with OTEC technology, and a more diverse group of people consisting of scientists from non-technical fields, industry people, politicians, investors, educators, and more. This volume is published as part of the publication series of the University of Borås, a progressive Swedish university with a high interest in and knowledge about sustainability.

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    FULLTEXT01
  • 12.
    Dessne, Petter
    et al.
    University of Borås, School of Business and IT.
    Golmen, Lars
    Johnson, Ted
    Bharathan, Desikan
    Lever, Harold
    Ny havsteknik kan lösa miljöproblem2014In: Svenska Dagbladet, ISSN 1101-2412, no 2014-02-08Article in journal (Other (popular science, discussion, etc.))
    Abstract [sv]

    Debattartikel som förespråkar miljötekniken OTEC för att förse stora delar av världen med energi och färskvatten.

  • 13.
    Eboh, Francis Chinweuba
    et al.
    University of Borås, Faculty of Textiles, Engineering and Business.
    Ahlström, Peter
    University of Borås, Faculty of Textiles, Engineering and Business.
    Richards, Tobias
    University of Borås, Faculty of Textiles, Engineering and Business.
    Estimating the specific chemical exergy of municipal solid waste2016In: Energy Science & Engineering, ISSN 2050-0505, Vol. 4, no 3, p. 217-231Article in journal (Refereed)
  • 14.
    Eboh, Francis Chinweuba
    et al.
    University of Borås, Faculty of Textiles, Engineering and Business. Resource Recovery.
    Ahlström, Peter
    Richards, Tobias
    Estimating the specific exergy of municipal solid waste2016In: Energy Science & Engineering, ISSN 2050-0505, Vol. 4, no 3, p. 217-231Article in journal (Refereed)
    Abstract [en]

    A new model for predicting the specific chemical exergy of municipal solid waste (MSW) is presented; the model is based on the content of carbon, hydrogen, oxygen, nitrogen, sulfur, and chlorine on a dry ash-free basis (daf). The proposed model was obtained from estimations of the higher heating value (HHV) and standard entropy of MSW using statistical analysis. The ultimate analysis of 56 different parts of MSW was used for the derivation of the HHV expression. In addition, 30 extra parts were used for validation. One hundred and seventeen relevant organic substances that represented the main constituents in MSW were used for derivation of the standard entropy of solid waste. The substances were divided into different waste fractions, and the standard entropies of each waste fraction and for the complete mixture were calculated. The specific chemical exergy of inorganic matter in the waste was also investigated by considering the inorganic compounds in the ash. However, as a result of the extremely low value calculated, the exergy of inorganic matter was ignored. The results obtained from the HHV model show a good correlation with the measured values and are comparable with other recent and previous models. The correlation of the standard entropy of the complete waste mixture is less accurate than the correlations of each individual waste fraction. However, the correlations give similar results for the specific chemical exergy, indicating that HHV has a greater impact when estimating the specific exergy of solid waste than entropy.

    Download full text (pdf)
    fulltext
  • 15.
    Eboh, Francis Chinweuba
    et al.
    University of Borås, Faculty of Textiles, Engineering and Business. Swedish Centre for Resource Recovery.
    Ahlström, Peter
    University of Borås, Faculty of Textiles, Engineering and Business. Swedish Centre for Resource Recovery.
    Richards, Tobias
    University of Borås, Faculty of Textiles, Engineering and Business. Swedish Centre for Resource Recovery.
    Exergy Analysis of Solid Fuel-Fired Heat and Power Plants: A Review2017In: Energies, E-ISSN 1996-1073Article in journal (Refereed)
    Abstract [en]

    The growing demand for energy is particularly important to engineers with respect to how the energy produced by heat and power plants can be used efficiently. Formerly, performance evaluation of thermal power plants was done through energy analysis. However, the energy method does not account for irreversibilities within the system. An effective method to measure and improve efficiency of thermal power plant is exergy analysis. Exergy analysis is used to evaluate the performance of a system and its main advantage is enhancement of the energy conversion process. It helps identify the main points of exergy destruction, the quantity and causes of this destruction, as well as show which areas in the system and components have potential for improvements. The current study is a comprehensive review of exergy analyses applied in the solid fuels heat and power sector, which includes coal, biomass and a combination of these feedstocks as fuels. The methods for the evaluation of the exergy efficiency and the exergy destruction are surveyed in each part of the plant. The current review is expected to advance understanding of exergy analysis and its usefulness in the energy and power sectors: it will assist in the performance assessment, analysis, optimization and cost effectiveness of the design of heat and power plant systems in these sectors.

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  • 16.
    Eboh, Francis Chinweuba
    et al.
    University of Borås, Faculty of Textiles, Engineering and Business.
    Ahlström, Peter
    University of Borås, Faculty of Textiles, Engineering and Business.
    Richards, Tobias
    University of Borås, Faculty of Textiles, Engineering and Business.
    Method of Estimating Absolute Entropy of Municipal Solid Waste2016In: World Academy of Science, Engineering and Technology, International Journal of Environmental, Chemical, Ecological, Geological and Geophysical Engineering, E-ISSN 2010-3778, Vol. 10, no 7, p. 689-694Article in journal (Refereed)
    Abstract [en]

    Entropy, as an outcome of the second law of thermodynamics, measures the level of irreversibility associated with any process. The identification and reduction of irreversibility in the energy conversion process helps to improve the efficiency of the system. The entropy of pure substances known as absolute entropy is determined at an absolute reference point and is useful in the thermodynamic analysis of chemical reactions; however, municipal solid waste (MSW) is a structurally complicated material with unknown absolute entropy. In this work, an empirical model to calculate the absolute entropy of MSW based on the content of carbon, hydrogen, oxygen, nitrogen, sulphur, and chlorine on a dry ash free basis (daf) is presented. The proposed model was derived from 117 relevant organic substances which represent the main constituents in MSW with known standard entropies using statistical analysis. The substances were divided into different waste fractions; namely, food, wood/paper, textiles/rubber and plastics waste and the standard entropies of each waste fraction and for the complete mixture were calculated. The correlation of the standard entropy of the complete waste mixture derived was found to be somsw= 0.0101C + 0.0630H + 0.0106O + 0.0108N + 0.0155S + 0.0084Cl (kJ.K-1.kg) and the present correlation can be used for estimating the absolute entropy of MSW by using the elemental compositions of the fuel within the range of 10.3%  C 95.1%, 0.0%  H  14.3%, 0.0%  O  71.1%, 0.0  N  66.7%, 0.0%  S  42.1%, 0.0%  Cl  89.7%. The model is also applicable for the efficient modelling of a combustion system in a waste-to-energy plant.

  • 17.
    Ehrnholm, Charlotta
    et al.
    University of Borås, Faculty of Textiles, Engineering and Business.
    Khaddam, Hicham
    University of Borås, Faculty of Textiles, Engineering and Business.
    Spillvattenvärmeväxlare – Examensarbete2021Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The report deals with wastewater heat exchangers with examples of products on the market, results on previous installations, suitability of installation with different water consumption and a calculation example based on a real building with a specific water consumption, with the aim of disseminating knowledge about the exchangers.

    The information has been collected through meetings with suppliers as well as web information, literature study and through both own calculations and calculations carried out by Evertherm on an example building from AB Bostäder that showed interest in the system.

    There are several different products on the market. Existing examples have had varying effects, and in several of the examples, it was not stated which exchanger was used. For the profitability calculations of AB Bostäder's building, which has a water consumption of approximately 19,000 𝑚3/𝑦𝑒𝑎𝑟, energy savings of 391 MWh / year and a net present value, (NPV) SEK 1.1 million was calculated with the present value method and SEK 1.8 million with the direct return method.

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    Spillvattenvärmeväxlare – Examensarbete
  • 18.
    Elled, A.-L.
    University of Borås, School of Engineering.
    Combustion of sludge with wood in a fluidised bed boiler- the fate of trace elements and sulphur performance2005Report (Other academic)
  • 19.
    Elled, Anna-Lena
    University of Borås, School of Engineering.
    Co-combustion of biomass and waste fuels in a fluidised bed boiler: fuel synergism2008Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The objective of this work was to study co-combustion of biomass and waste fuels in a circulating fluidised bed boiler and to detect synergy effects with respect to flue gas composition and ash formation during boiler operation. It was also the aim to perform supplementary thermodynamic equilibrium calculations in order to support the experimental results. The base fuel used was either wood or bark pellets and the additional fuels included municipal sewage sludge, sludge from the pulp and paper industry and demolition wood. In some of the tests, additives were supplied to the boiler to enhance any effects from substances of special interest. Examples of such additives are zinc oxide, PVC, ammonium sulphate, kaolin and zeolites. The 12 MWth circulating fluidised bed boiler situated at Chalmers University of Technology was central to the investigation. All combustion tests were performed in this boiler and it provided operating data, flue gas composition and samples of fuel, ash and deposits under required combustion conditions. Great effort was put into the analyses of ashes and deposits and in excess of conventional techniques, time-of-flight secondary ion mass spectrometer (TOF-SIMS), scanning electron microscopy energy dispersive x-ray (SEM EDX) and x-ray diffraction (XRD) were applied to several of the samples to create a more complete scan of the constituents. The thermodynamic equilibrium calculations were performed using the computer program FactSage and the module EQUILIB. The thermodynamic data was collected from the database FACT. The focus of the investigation was directed towards three main areas: sulphur capture performance by lime addition to the bed, distribution of heavy metals in ashes and flue gas, and formation of deposits on heat transfer surfaces in the convective pass and the use of municipal sewage sludge as a preventive additive. The relatively high content of phosphorus in municipal sewage sludge interferes with the sulphur capture by lime and decreases the sulphur capture performance. Phosphorus reacts with calcium, which otherwise is available for reaction with sulphur, and forms compounds such as calcium phosphates. The formation was supported by equilibrium calculations and proved by analysing the ashes with TOF-SIMS. The decreased lime efficiency must be taken into account when sulphur capture strategies are decided for the reduction of SO2 emissions from co-combustion of municipal sewage sludge. Further, the use of bark pellets as base fuel during co-combustion with sulphur containing wastes reduces the sulphur emissions due to their relatively high content of calcium and potassium in connection with its low content of sulphur. The supply of heavy metals to the combustion increases dramatically when wood is replaced by municipal sewage sludge under otherwise constant conditions. The heavy metals are to a large extent recovered in the ash and captured by the flue gas cleaning system. Even the most volatile species, such as mercury, are captured and enriched in the fine fly ash. The effective metal capture is partly due to the sludge ash and partly to the bag filter. The amount of ash in the boiler increases with the sludge and the fine fly ash fraction constitutes a high particle surface area which enhances the capture of volatile metals. Further, the ash contains large amounts of several elements known to retain trace elements such as aluminium, calcium, carbon and silicon. Especially the presence of zeolites in the sludge is likely to contribute to the capture of mercury. Further, the enrichment ratios of metals in the filter ash indicate the necessity of including bag-filters in the flue gas cleaning system in order to achieve sufficient removal of toxic heavy metals. Zinc, and its effect on deposit formation, was given special attention since the metal is commonly present in demolition wood. The result showed that combustion of demolition wood contaminated with zinc alone generates only a modest amount of deposits. Demolition wood contaminated with both zinc and chlorine gives rise to more severe deposit formation. The main reason for this is the formation of alkali chlorides but also zinc chlorides in the flue gas. The formation of zinc chlorides is, under reducing conditions, thermodynamically favoured between 450 and 850°C. Under oxidising conditions, the formation is initiated at 400°C and gradually increased with the temperature. Municipal sewage sludge is not only a waste that must be disposed of, it can also be regarded as an additive to prevent deposit formation during combustion of high alkali biomass. The sludge reduces the concentration of KCl in the flue gas, impedes the deposit formation and eliminates the content of chlorine in the deposits. The occurrence is clear of though the fuel is contaminated with chlorine. The effect is partly due to sulphation of potassium and partly to potassium sequestration by the sludge ash.

  • 20.
    Elled, Anna-Lena
    et al.
    University of Borås, School of Engineering.
    Åmand, Lars-Erik
    University of Borås, School of Engineering.
    Andersson, Bengt-Åke
    University of Borås, School of Engineering.
    Leckner, B.
    University of Borås, School of Engineering.
    Phosphorus in ash from co-combustion of municipal sewage sludge with wood in a CFB boiler: A comparison of experimental data with predictions by a thermodynamic equilibrium model2005Conference paper (Refereed)
    Abstract [en]

    Combustion tests have been carried out in a circulating fluidised bed (CFB) boiler co-firing wood and municipal, digested and mechanical dewatered sewage sludge from two Swedish wastewater treatment plants, using either iron sulphate or aluminium sulphate as precipitating chemicals. Experimental data on the concentration of various phosphorous compounds in the ashes are compared with theoretical equilibrium predictions. A clear relationship is not found between the employed precipitation chemical and the formation of phosphorous compounds in the ash. Hematite (Fe2O3(s)) is predicted to be the stable iron compound, and even in the sludge precipitated by iron sulphate, the aluminium content is sufficient to form aluminium phosphate (AlPO4(s)) in similar amounts as in the sludge precipitated by aluminium sulphate. Lime addition to the bed gives a decreased formation of AlPO4(s) in favour of calcium orthophosphate (Ca3(PO4)2(s)), which interferes with the sulphur capture efficiency of lime.

  • 21.
    Elled, Anna-Lena
    et al.
    University of Borås, School of Engineering.
    Åmand, Lars-Erik
    Eskilsson, David
    The fate of zinc during combustion of demolition wood in a fluidized bed boiler2007In: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 22, no 3Article in journal (Refereed)
    Abstract [en]

    Demolition wood can be used as a fuel in heat and power plants. However, it may contain elevated amounts of zinc, originating from white paint, which can cause problems related to deposit formation and corrosion on heat transfer surfaces. In this work, combustion tests with zinc addition were carried out in a fluidized bed boiler to investigate its effect on deposit formation. Thermodynamic equilibrium calculations were performed to complement the experimental data. The results show that combustion of demolition wood only contaminated with zinc generates a modest amount of deposit. Combustion of demolition wood contaminated with both zinc and chlorine promotes the deposit formation due to the increased amount of submicron particles in the flue gas. The thermodynamic equilibrium analyses show further that reducing conditions increase the release of zinc to the flue gas. On the other hand, in the case of oxidizing conditions, the retention of zinc in the ash is strong. Zinc, in combination with chlorine, gives rise to formation of zinc chloride in the flue gas. The formation is, at reducing conditions, thermodynamically favored between 450 and 850 °C. At oxidizing conditions, the formation is initiated at 400 °C and gradually increased with the temperature.

  • 22.
    Elled, Anna-Lena
    et al.
    University of Borås, School of Engineering.
    Åmand, Lars-Erik
    Leckner, Bo
    Andersson, Bengt-Åke
    University of Borås, School of Engineering.
    The fate of trace elements in fluidised bed combustion of sewage sludge and wood2006In: Fuel, ISSN 0016-2361, E-ISSN 1873-7153, Vol. 86, no 5-6, p. 843-852Article in journal (Refereed)
    Abstract [en]

    Combustion tests have been carried out in a fluidised bed boiler to investigate the fate of trace elements during co-combustion of wood and municipal sewage sludge. The approach was to collect fuel and ash samples and to perform thermodynamic equilibrium calculations for gasification (reducing) and combustion (oxidising) conditions. Trace elements are found in the ash. Even most of the highly volatile Hg is captured in the bag filter ash. The bag filter ash offers higher surface area than the secondary cyclone ash and enhances the capture of Hg. There is no obvious correlation between capture and parameters investigated (sludge precipitation agent and lime addition). As, Cd, Hg, Pb, Se, Sb and Tl are predicted by equilibrium calculations to be volatile in the combustion chamber under oxidising conditions and Hg even at the filter temperature (150°C). Reducing conditions promote, in some case more than others, the volatility of As, Cd, Pb, Sb, Se, Tl and Zn. The opposite effect was observed for Cu and Ni. Data points to the necessity of including bag-filter in the gas cleaning system in order to achieve good removal of toxic trace elements.

  • 23.
    Elled, Anna-Lena
    et al.
    University of Borås, School of Engineering.
    Åmand, L.-E.
    Leckner, B.
    Andersson, Bengt-Åke
    University of Borås, School of Engineering.
    Influence of phosphorus on sulphur capture during co-firing of sewage sludge with wood or bark in a fluidised bed2006In: Fuel, ISSN 0016-2361, E-ISSN 1873-7153, Vol. 85, no 12, p. 1671-1678Article in journal (Refereed)
    Abstract [en]

    Interference from phosphorus on sulphur capture during co-firing of sludge with wood has been investigated in a circulating fluidised bed boiler. Chemical equilibrium analyses were performed on the combustion system to complement the experimental results. It was found that the relatively high content of phosphorus in municipal sewage sludge interferes with the sulphur capture by occupying calcium, which otherwise would be available for reaction with sulphur. This fact must be taken into account when sulphur capture strategies are decided for reduction of sulphur dioxide emissions from sewage sludge as an additional fuel.

  • 24.
    Ericsson, Daniel
    et al.
    University of Borås, Faculty of Textiles, Engineering and Business.
    Lagergren, Ida
    University of Borås, Faculty of Textiles, Engineering and Business.
    Lutens kretslopp på Södra Cell Värö2017Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Rapporten handlar om lutens kretslopp på Södra Cell Värö, dess betydelse för pappersmassaproduktionen samt riskerna som finns vid användning av lut. Lut används när pappersmassa framställs på Södra Cell Värö (sulfatprocess). Kokeriet kokar träflis, tunnlut (svartlut) och vitlut. Luten tillsätts för att lösa upp ligninet i träfibrerna. Lignin är som ett lim som håller ihop träfibrerna. Lutvätskan som lämnar kokeriet kallas för tunnlut och indunstningen torkar tunnluten i flera steg. När luten har torkats kallas den för brännlut (tjocklut) och förbränns i sodapannan. Smältan från sodapannan blandas med svaglut och bildar grönlut. I grönluten tillsätts bränd kalk och bildar kalkmjölk. Ur kalkmjölken separeras vitlut och mesa. Vitluten återinförs till kokeriet och kretsloppet fortsätter. Luten har stor betydelse för produktionen av pappersmassa på Södra Cell Värö. Om någon del i lutkretsloppet inte fungerar tvingas hela fabriken att stanna. Användning av lut är inte riskfritt. Lut är ett frätande ämne och det räcker med små kvantiteter för att orsaka stor skada. Därför är det viktigt att rätt skyddsutrustning används och respekt visas. Om Södra Cell Värö inte skulle använda lut skulle tillverkningsprocessen se annorlunda ut. Mekanisk process eller sulfitprocess skulle användas istället. Fördelarna med att använda lut är att kvalitén på pappersmassan blir bättre. Därför får pappersmassan ett större användningsområde. Nackdelarna med att använda lut är dels risken för olyckor, dels att vedutbytet endast är 50 %. Syftet med rapporten är att ge läsaren lärdom om hur lutens kretslopp fungerar och lutens betydelse på ett massabruk som Södra Cell Värö samt informera om vilka risker det finns vid arbete med lut.

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  • 25.
    Francis Chinweuba, Eboh
    University of Borås, Faculty of Textiles, Engineering and Business.
    Efficiency Improvements in Waste-to-Energy Combustion Processes: Method Development and Evaluation2019Doctoral thesis, monograph (Other academic)
    Abstract [en]

    is the energy recovery method. The electrical efficiency of this technology, however, is generally low when compared with other solid fuel-fired combustion plants as a result of low steam properties. Furthermore, there is lack of efficient methods to evaluate the performance of this system. The energy method, normally used, does not account for exergy destruction due to entropy generated within the system.In this thesis, an exergy model for estimating the maximum available energy in a municipal solid waste and a modified exergy-based method for calculating the improvement potential in a waste-to-energy plant are developed. The exergy model was obtained from estimations of the higher heating value and standard entropy of municipal solid waste from the elemental compositions of the waste using statistical analysis. The improvement potential was derived by comparing the exergy destruction of the real process with its corresponding theoretical process. It was applied in a solid-waste fired heat and power plant to investigate possible improvements in the system as well as the cost of the improvements. The different improvement modifications considered include the re-arrangement of air heaters, the introduction of a reheater, flue gas condensation and an integrated gasification-combustion process. Modelling, simulation and cost estimations were performed with the Aspen Plus software.

    The results showed that the present proposed exergy model was more accurate than the previous models for estimating the maximum available energy in waste material, as the proposed model incorporates all the major elemental constituents as well as the physical composition of the solid waste. Moreover, the results obtained from the higher heating value model show a good correlation with the values measured, and are comparable with other recent and previous models. Furthermore, it was found that 64 % of the total exergy destruction in the process plant investigated can be reduced, while the boiler was identified as a component with the greatest potential for making improvements to the plant. Although the integrated gasification-combustion technology with flue gas condensation has the highest exergy efficiency, its higher capital cost exceeds all other alternatives. The improvement modifications with flue gas condensation not only provide the highest heat production but also the highest net present value. This indicates that flue gas condensation has a significant impact on the overall income generated by waste-to-energy combined heat and power industries.

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  • 26.
    Gren, Nils
    et al.
    University of Borås, Faculty of Textiles, Engineering and Business.
    Lundblad, Tobias
    University of Borås, Faculty of Textiles, Engineering and Business.
    Solceller i Borås: Nyttjande av solceller för Borås energi och miljö2021Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The purpose of the study is to find solutions for Borås energi och miljö on how to effectively establish solar cells, by comparing with other municipalities / companies and thus find one or more solution proposals. A location in the Borås area for any photovoltaic system will also be proposed.

    Fact collection will take place via internet websites and interviews. The interviews are divided into two categories. Questions that are more technically oriented, are asked primarily to companies and institutes. And questions that are aimed at owners of photovoltaic systems, such as municipalities and companies. The interviews were held via Teams, with recording. The recording was only to ensure that no information was wasted, of course with the person's permission. Due to lack of time on the part of the companies, some interviews were held by telephone, without recording. During the project, six people from different companies and municipalities were interviewed. The results of the interviews gave similar results. For the companies that owned a photovoltaic plant, the majority had monocrystalline solar cells. The technically oriented interviews also gave similar results as they mentioned that monocrystalline solar cells were the more advantageous variant. When asked about the use of storage or optimizers, the answers were no for all interviews. When compared with the fact collections collected via the website, it gave a similar result.

    Our solution proposed to Borås energi och miljö is to use a monocrystalline half-cut solar cells without storage or optimizers in a future facility. Location would preferably be on unusable land, such as closed landfills or rooftops.

    Choice of location for possible future solar cell plant, was decided by help of a cell map over Borås and collaboration with staff at -Borås energi och miljö.

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    Solceller i Borås
  • 27.
    Johansson, Andreas
    University of Borås, School of Engineering.
    Siktning av avfall2008Other (Other academic)
  • 28.
    Johansson, Andreas
    University of Borås, School of Engineering.
    Waste refinery -joint initiatives towards improved energy recovery from waste2008In: Proceedings of World Bioenergy, conference & Exhibition on Biomass for Energy, oral sessions., 2008, p. 45-49Conference paper (Other academic)
  • 29.
    Johansson, Andreas
    et al.
    University of Borås, School of Engineering.
    Eskilsson, David
    Johansson, Linda
    Wikström-Blomqvist, Evalena
    Andersson, Bengt-Åke
    University of Borås, School of Engineering.
    Johnsson, Anders
    Combustion of Demanding Waste Fractions in a 10 MWe Waste-toEnergy Plant2007In: In Proceeding of ISWA/NVRD World Congress 2007, 2007Conference paper (Other academic)
  • 30.
    Johansson, Andreas
    et al.
    University of Borås, School of Engineering.
    Johnsson, Filip
    Niklasson, Fredrik
    Åmand, Lars-Erik
    Dynamics of furnace process in a CFB boiler2007In: Chemical Engineering Science, ISSN 0009-2509, E-ISSN 1873-4405, Vol. 62, no 1-2, p. 550-560Article in journal (Refereed)
    Abstract [en]

    With the aim of understanding the dynamics of combustion, this work examines simultaneous fluctuations in fluid dynamic parameters and gas composition measured in a CFB furnace operated with coal as a fuel. The fluid dynamic parameters investigated are pressure and air flow entering the furnace. Gas composition was recorded by a zirconia-cell probe and a gas suction probe connected to a mass spectrometer having a high time resolution (10 Hz). The principal fluctuations detected are around I Hz and below 0.3 Hz. The fluctuations below 0.3 Hz mostly originate from variations in the fuel-feed rate. These variations create periods of reducing conditions caused by a momentarily high fuel input accompanied by a pressure rise in the furnace and a reduction of the air feed, which occurs concurrent with the release of an enhanced quantity of volatiles. Modelled pressure fluctuations based on the relation between volatile release and pressure in the furnace give similar pressure fluctuations as the measured pressure fluctuations, with respect to amplitude and characteristic time scale of the fluctuations. There is also a correlation between reducing conditions and the concentration of hydrocarbons. (c) 2006 Elsevier Ltd. All rights reserved.

  • 31.
    Johansson, Michael
    University of Borås, Faculty of Textiles, Engineering and Business.
    Hantering av IFC-exporter från Revit till IDA2017Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    It is extremely important to be able to export models directly from Revit to IDA for the energy simulations to be efficient. This report has a background description about how the IFC-format has been developed and how it is structured. However, the focus in the report is on how Revit can be implanted in the workflow, where both export and troubleshooting from Revit are described. IFC is the standard today to export data between various parts during the construction process and it is a format that is program independent, which means that it works across different applications. The current version of IFC is IFC4, but IFC2x3 is still the most used version since not every program has support for the new IFC4 format. It is extensive to figure out which data IDA requires for energy simulations, therefore this report contains both a tutorial for export settings and a file for automatic set correct export settings in Revit. To succeed with the energy simulations a requirement is that the space in the building is enclosed with walls, floor and roof, otherwise extreme thermal bridges will cause incorrect simulations. Therefore, there are several workarounds described in this report to correct these problems, including problems with windows, doors and problems with storage facilities . The description in this report is written with the assumption that the user do not have any experience with Revit. The guides were tested on a class of high school students that are studying the course CADCAD02. The result showed that when a problem occurs with a model it can easily be solved with the support from this report. Further differences between simulations in Revit and IDA were tested. The same model was simulated in eight different places and the standard deviation was calculated, this gave the coefficient range ±4 %, i.e. a simulation in IDA should not differ more than 4 % from the simulation in Revit. Similar results were found with the simulations of windows and doors, even though the difference was slightly lower.

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  • 32.
    Keshtkar, Mehrdad
    University of Borås, Faculty of Textiles, Engineering and Business.
    Översyn av sandåterföringsprocess: av panna 6 vid Högdalenverket2021Independent thesis Basic level (degree of Bachelor), 180 HE creditsStudent thesis
    Abstract [en]

    Högdalen power plant is part of Stockholm Exergi's concern, which is jointly owned by the City of Stockholm together with Fortum. Boiler 6 in Högdalen is a circulating fluidized-bed type, CFB. The boiler was built in 1999 by Foster Wheeler and has been combusting industrial waste as feedstock. Boiler 6 uses sand as bed material. A study was carried out about the sand recycling process which did not work optimally. This created a deterioration in resources in the form of negative environmental impact and led to additional work for staff, additional production costs as well as poor availability of the facility. The study aimed to determine the reason for the problem and then investigate various methods as a measure. Several reasons were determined for why the process did not work optimally and the most important reason thought to be the sand transmitter which is not adapted to the fuel that the boiler uses. Various modifications and methods have been made to adapt the sand transmitter, such as extending supervision, changing sensor positions, increasing delay time for components and pressure adjustment without improving the position. As a result of the study, two proposals were developed to address the issue, of which the company chose to proceed with one of the proposals which led to a component change.  

  • 33.
    Khan, A.
    et al.
    Department of Chemical and Polymer Engineering, University of Engineering and Technology Lahore, Faisalabad Campus, Pakistan.
    Rashid, M.
    Department of Chemical, Polymer and Composite Materials Engineering, Kala Shah Kaku Campus, University of Engineering and Technology Lahore, Lahore, 39021, Pakistan.
    Rehman, A.
    Department of Chemical and Polymer Engineering, University of Engineering and Technology Lahore, Faisalabad Campus, Pakistan.
    Saleem, F.
    Department of Chemical and Polymer Engineering, University of Engineering and Technology Lahore, Faisalabad Campus, Pakistan.
    Naqvi, S. R.
    School of Chemical & Materials Engineering, National University of Sciences & Technology, 44000, Islamabad, Pakistan.
    Afzal, S.
    Department of Basic Sciences and Humanities, MNS University of Engineering and Technology Multan, Pakistan.
    Qazi, U. Y.
    Department of Chemistry, College of Science, University of Hafr Al Batin, Kingdom of Saudi Arabia.
    Ahmad, W.
    Department of Built Environment and Energy Technology, Linnaeus University, Sweden.
    Butt, Iftikhar Nisar
    University of Borås, Faculty of Textiles, Engineering and Business.
    Mahmood, K.
    Department of Chemical and Polymer Engineering, University of Engineering and Technology Lahore, Faisalabad Campus, Pakistan.
    A comprehensive review of the methane decomposition using a gliding arc discharge reactor for hydrogen generation2023In: Journal of the Energy Institute, ISSN 1743-9671, E-ISSN 1746-0220, Vol. 109, article id 101309Article in journal (Refereed)
    Abstract [en]

    The use of fossil fuels has caused an ongoing increase in greenhouse gases (GHGs), which have a negative impact on both the environment and human health. The world requires an alternative green sustainable fuel that can solve these problems. Hydrogen (H2) can be considered as an alternative green energy source as it has zero carbon emissions. Methane (CH4) decomposition is a potential technique to produce H2 fuel. Gliding arc discharge (GAD) reactors have gained significant attention to produce H2 from the decomposition of CH4. This review focuses on the application of GAD reactors for CH4 conversion. The effects of different parameters, such as operation conditions, additives, geometric configuration, and catalysts, on the performance of the GAD reactor, are discussed in this review. © 2023 Energy Institute

  • 34.
    Klasson, Albin
    University of Borås, Faculty of Textiles, Engineering and Business.
    Strömmätsystem för 10 000 Ampere: Enligt Rogowskiprincipen2023Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    At RISE’s (Research Institutes of Sweden) department for measurements and technology is calibration a big part of the work, the unit for high voltage have a desire to expand their capabilities in measurements of AC currents at power frequency up to 10 000 A.   

    The objective is to with the Rogowski principle construct a measuring rig for calibration of current transformers at customer laboratories. With precision of at least 100 ppm and 100 µrad for currents up to 10 000 A.  

    The project starts with the design of the rig, then focus on tests and possible improvements of an already bought Rogowski coil and integrator.  

    The final construction was made in aluminum with a concentric design where the return conductor is a tube surrounding the main conductor which the Rogowski coil was centered around. The integrator to the coil were not good enough and a new one was made, which were optimized to minimize the impact of temperature changes and give stable response to a desired frequency spectrum. 

    To great extent the project was a success, even though some challenges remain. The temperature compensation was not fully optimized, and the temperature rise are still too high. Today the measuring system do measurements with high accuracy at lower currents and are expected to preform according to the objective if you take in consideration either: lower current, shorter time with current or a lower accuracy.  

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  • 35.
    Kundariya, Nidhi
    et al.
    Gujarat Pollution Control Board, Gandhinagar-382 010, Gujarat, India.
    Mohanty, Swayansu Sabyasachi
    Gujarat Pollution Control Board, Gandhinagar-382 010, Gujarat, India.
    Varjani, Sunita
    Gujarat Pollution Control Board, Gandhinagar-382 010, Gujarat, India.
    Hao Ngo, Huu
    Centre for Technology in Water and Wastewater, School of Civil and Environmental Engineering, University of Technology Sydney, Sydney, NSW 2007, Australia.
    W. C. Wong, Jonathan
    Institute of Bioresource and Agriculture, Hong Kong Baptist University, Hong Kong, PR China.
    Taherzadeh, Mohammad J
    University of Borås, Faculty of Textiles, Engineering and Business.
    Chang, Jo-Shu
    Department of Chemical Engineering and Materials Science, College of Engineering, Tunghai University, Taichung, Taiwan.
    Yong Ng, How
    National University of Singapore, Environmental Research Institute, 5A Engineering Drive 1, Singapore 117411, Singapore.
    Kim, Sang-Hyoun
    School of Civil and Environmental Engineering, Yonsei University, Seoul 03722, Republic of South Korea.
    Bui, Xuan-Thanh
    Faculty of Environment and Natural Resources, Ho Chi Minh City University of Technology (HCMUT), Ho Chi Minh City 700000, Vietnam.
    A review on integrated approaches for municipal solid waste for environmental and economical relevance: Monitoring tools, technologies, and strategic innovations2021In: Bioresource Technology, ISSN 0960-8524, E-ISSN 1873-2976, Vol. 342Article, review/survey (Refereed)
    Abstract [en]

    Rapid population growth, combined with increased industrialization, has exacerbated the issue of solid waste management. Poor management of municipal solid waste (MSW) not only has detrimental environmental consequences but also puts public health at risk and introduces several other socioeconomic problems. Many developing countries are grappling with the problem of safe disposing of large amounts of produced municipal solid waste. Unmanaged municipal solid waste pollutes the environment, so its use as a potential renewable energy source would aid in meeting both increased energy needs and waste management. This review investigates emerging strategies and monitoring tools for municipal solid waste management. Waste monitoring using high-end technologies and energy recovery from MSW has been discussed. It comprehensively covers environmental and economic relevance of waste management technologies based on innovations achieved through the integration of approaches.

  • 36.
    Lindholm, Helena
    et al.
    University of Borås, Faculty of Textiles, Engineering and Business.
    Dahlby, Susanne
    University of Borås, Faculty of Textiles, Engineering and Business.
    LCA på byggnaden och dess installationer: Utsläpp av växthusgaser vid produktion av isolering kontra energianvändningen i nya byggnader2023Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Approximately one-fifth of Sweden's total emissions of carbon dioxide equivalents (CO2e) come from the construction sector. Energy usage in buildings has decreased over time, yet the CO2e emissions from the construction sector have remained unchanged. Even the building's installations have been overlooked despite the fact that they account for a significant proportion of the emissions linked to a building's life cycle. A life cycle analysis on a building can allow us to calculate and identify activities where emissions occur and prioritize areas that require further focus.

    The purpose of the study was to conduct a life cycle analysis of insulation materials in the building body and the installations in a new construction project; a preschool in Sundbyberg. A comparison was made between the CO2e emissions from insulation with various thicknesses and the CO2e emissions from the energy that is used during the building's lifetime.

    Three models of different insulation thicknesses were created, to compare the building's energy needs. For each model, different energy sources were used as a variable to identify the different impacts on a building’s CO2e-emissions.

    A theoretical future scenario was also created where the electricity and district heating sectors would move towards zero emissions by 2045. A different approach was taken for the installations, due to the lack of information in the area. A tool for the insulation of pipes and ducts was developed to be able to perform calculations on its CO2e-emission and compare it with the emissions of heat losses.

    Depending on the choice of energy source, the result varied, when less insulation was chosen, the emissions of the local energy sources benefited. However, in terms of Boverket's generic values, a cut-off point arose after 15 years where the choice of more insulation meant that the total CO2e-emissions decreased over a period of 60-years. For the future scenario, both cases showed that less isolation was the better option seen over the same period. The result is also affected by the limitations that the study has related to, for example, no consideration has been given to the secondary effects such as the extended floor structure, which becomes a natural effect of isolating more.

    In order to meet Sweden's climate goals of becoming climate neutral by 2045, emissions linked to the construction sector need to be reduced.

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  • 37.
    Lindström, Ida
    et al.
    University of Borås, Faculty of Textiles, Engineering and Business.
    Nyrén, Alexander
    University of Borås, Faculty of Textiles, Engineering and Business.
    Värmeåtervinning ur spillvattensystem2023Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    In 2020, the construction sector accounted for 21% of Sweden’s total emissions of carbon dioxide equivalents but has since 2019 decreased as result of reduced emissions from the electricity and district heating sector. By making smart choices regarding systems and material when rebuilding and project planning could the construction sector be made more energy efficient and the total environmental impact may be reduced. Energy losses that occur in buildings today may be recovered to some extent with for example heat recovery units for ventilation and by sealing the building structure better. Hot water energy that is flushed away can be utilized trough heat exchangers for wastewater in order to recover heat from the water. The purpose of this study was to theoretically investigate the profitability of installing heat exchangers for wastewater on vertical sewer pipes in Glesvingen as well as determine which factors that affect the profitability the most. A calculation model based on existing data has been created in order to achieve this. This model then laid the foundation for specific theoretical energy calculations for Glesvingen. Data from Bostäder i Borås has also been3collected regarding temperatures as well as the amount of cold and hot water. In order to understand the profitability, various economical calculations have been made. In the result the amount of recovered energy and how it was affected by the number of wastewater sewer pipes in the building as well as the temperature of the wastewater flow was presented. The result also show the energy saving when the hot and cold wastewater flows are separated. Comparisons of the profitability calculations are presented as cost, savings and resulting savings over 50 and 25 years respectively. In conclusion, a compilation of different profitability calculations for Glesvingen has been made for different conditions. Regarding the installation of heat exchangers in Glesvingen, this investment is not considered profitable with the current building layout.

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  • 38.
    Manhica, Fabiao
    et al.
    University of Borås, School of Engineering.
    Lucas, Carlos
    Richards, Tobias
    University of Borås, School of Engineering.
    Wood Consumption and Analysis of the Bread Baking Process in Wood-Fired Bakery Ovens2012In: Applied Thermal Engineering, ISSN 1359-4311, E-ISSN 1873-5606, Vol. 5, no 47, p. 63-72Article in journal (Refereed)
    Abstract [en]

    Combustion of biomass in small-scale furnaces is used widely in different applications. The technology used is often “fixed grate” combustion in small batch furnaces. The efficiency of such a furnace is often low, which results in a high environmental impact. The aim of this work was to analyse the performance of the existing wood-fired bakery ovens that can be used to improve the efficiency. The data collected from 15 semi-direct and 3 indirect bakeries consisted of: the dimensions of the oven, the temperature profiles of the combustion chamber and the baking oven, the baking time and the bread quality. It was found that as much as 60 tons/day of green wood are consumed in the bread baking process in the area investigated. Two types of bakery ovens are used most commonly: indirect and semi-direct. The specific consumption was found to be 0.55 and 0.90 kg of wood per kg of wheat flour baked for the indirect and the semi-direct respectively. The analyses of the bread baked show that the variation of the temperature profile during the baking process influences the quality of the bread produced.

  • 39.
    Moradian, Farzad
    University of Borås, School of Engineering.
    Co-Combustion of Municipal Solid Waste and Animal Waste: Experiment and Simulation Studies2013Licentiate thesis, monograph (Other academic)
    Abstract [en]

    Co-combustion of animal carcasses and slaughterhouse waste products (animal waste), which are classed as high-risk infectious waste, has been considered as a “fuel opportunity” for waste-to-energy boilers. In this study, the impact of co-combustion of animal waste with municipal solid waste (MSW) on operational issues such as bed agglomeration, deposit formation and emission was investigated, employing experimental and theoretical methods. In the experimental section, a series of full-scale tests in a bubbling fluidised-bed boiler were carried out, to determine the effects of animal waste co-combustion on the issues addressed. Two combustion scenarios were considered, identified as the reference (Ref) case and the animal waste (AW) case. In the Ref case, a solid-waste fuel mix, consisting of sorted and pretreated industry and household waste was combusted. In the AW case, 20 wt% AW was added to the reference fuel mix. The collected samples, which included super-heater deposits, fuel mixes and bed and fly ashes, were analysed, using chemical fractionation, SEM-EDX and XRD. In addition, the flue gases´ emission rate were continuously analysed, using FTIR spectrometry. The results showed positive effects from co-combustion of AW, indicating decreased deposit formation and lower risk of bed agglomeration, as well as reduced emissions of NOx and SO2. Moreover, it was found that the concentrations of P, Ca, S and Cl were enriched in the bed materials. In the theoretical section, thermodynamic calculations, with respect to experimental data, were performed to provide greater understanding of the ash transformation behaviour and the related melting temperature. The calculations mainly focused on bed agglomeration, where addition of AW to the MSW considerably reduced the risk of agglomeration. The results of equilibrium products and phase diagram information for the bed ashes suggested melt-induced agglomeration as a possible cause of the formation of sticky layers on the bed particle in the Ref case. Moreover, it was concluded that higher amounts of calcium phosphate and sulfates increased the first melting temperature of the bed ashes in the AW case.

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  • 40.
    Moradian, Farzad
    et al.
    University of Borås, Faculty of Textiles, Engineering and Business.
    Pettersson, Anita
    University of Borås, Faculty of Textiles, Engineering and Business.
    Richards, Tobias
    University of Borås, Faculty of Textiles, Engineering and Business.
    Thermodynamic Equilibrium Model Applied to Predict Fouling Tendency in a Commercial Fluidized-Bed Boiler, Combusting Solid Waste2015In: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 29, no 5, p. 3483-3494Article in journal (Refereed)
    Abstract [en]

    A thermodynamic equilibrium model, combined with an advanced fuel analysis, was applied to predict the fouling tendency in a commercial bubbling fluidized-bed (BFB) boiler, combusting a mixture of solid waste. In order to enhance the performance of the model, further modifications were made, considering the combustion pattern in the fluidized-bed system and also the temperature profile in the combustion zone. The modeling was performed using Factsage, and experimental data obtained during the full-scale measurements were used as input for the model, simulating the deposit formation in the real boiler. The simulation results were then compared with the results obtained during the full-scale combustion tests to estimate the accuracy and validity of the applied model. The thermodynamic equilibrium modeling proved to be a reliable tool for predicting the fouling in the BFB boiler, thus determining the fraction of the melt in the deposited salts formed on the heat transfer surfaces during the flue gas condensation. The calculations showed that the ratio of the SO2 to alkali chloride concentration in the flue gas was the decisive factor that affected the rate of the deposit formation in the boiler. Both the simulation and the experimental results indicated that lower bed temperatures and cocombustion of P-rich fuels decrease the deposition buildup in the boiler. © 2015 American Chemical Society.

  • 41.
    Mukesh Kumar, Awasthi
    et al.
    University of Borås, Faculty of Textiles, Engineering and Business. College of Natural Resources and Environment, Northwest A&F University, Yangling, Shaanxi Province, 712100, PR China; .
    Singh, E
    CSIR-National Environmental Engineering Research Institute, Nagpur, Maharashtra, 440 020, India.
    Binod, P
    CSIR-National Institute for Interdisciplinary Science and Technology (CSIR- NIIST), Thiruvananthapuram, Kerala, 695 019, India.
    Sindhu, R
    CSIR-National Institute for Interdisciplinary Science and Technology (CSIR- NIIST), Thiruvananthapuram, Kerala, 695 019, India.
    Sarsaiya, S
    Key Laboratory of Basic Pharmacology and Joint International Research Laboratory of Ethnomedicine of Ministry of Education, Zunyi Medical University, Zunyi, Guizhou, China.
    Kumar, A
    CSIR-National Environmental Engineering Research Institute, Nagpur, Maharashtra, 440 020, India.
    Chen, H Y
    Institute of Biology, Freie Universität Berlin Altensteinstr, Berlin, Germany.
    Duan, Y M
    College of Natural Resources and Environment, Northwest A&F University, Yangling, Shaanxi Province, 712100, PR China.
    Pandey, A
    Centre for Innovation and Translational Research, CSIR-Indian Institute of Toxicology Research (CSIR-IITR), Lucknow, 226 001, India.
    Kumar Ramamoorthy, Sunil
    University of Borås, Faculty of Textiles, Engineering and Business.
    Taherzadeh, Mohammad J
    University of Borås, Faculty of Textiles, Engineering and Business.
    Li, J
    College of Resources and Environmental Sciences, China Agricultural University, Yuanmingyuan West Road No.2, Haidian District, 100193, Beijing, China.
    Zhang, Z Q
    College of Natural Resources and Environment, Northwest A&F University, Yangling, Shaanxi Province, 712100, PR China.
    Biotechnological strategies for bio-transforming biosolid into resources toward circular bio-economy: A review2022In: Renewable & sustainable energy reviews, ISSN 1364-0321, E-ISSN 1879-0690, Vol. 156, article id 111987Article, review/survey (Refereed)
    Abstract [en]

    Biosolids are the biological organic matter extracted from various treatment processes of wastewater which are considered as a rich source of energy and nutrients. The most commonly used method for the disposal of biosolids is landfilling. But this causes the loss of valuable nutrients and creates environmental issues. Circular economy approaches provide a better way for utilization these resources in a sustainable manner. This allows maximum utilization of resources and many natural resources can be preserved and utilized for future generations. The present review provides a comprehensive illustration of biotechnological approaches for the utilization of biosolids. Various process strategies for the utilization of biosolids for the production of energy, fuels and valueadded products are discussed. The utilization of this rich organic matter under circular economy has also been described in detail.

  • 42.
    Oluoti, Kehinde
    et al.
    University of Borås, School of Engineering.
    Megwai, Godswill
    Pettersson, Anita
    University of Borås, School of Engineering.
    Richards, Tobias
    Nigerian Wood Waste: A Dependable and Renewable Fuel Option for Power Production2014In: World Journal of Engineering and Technology, ISSN 2331-4222, Vol. 2, p. 234-248Article in journal (Refereed)
    Abstract [en]

    Being an oil - rich country, Nigeria’s energy supply is primarily fossil - based. The unequal distribu - tion of oil wealth, along with agitation for self - determination and resource control, has led to the sabotage of oil installations. This, in turn, has affected all services running on the energy supply from these installations, leading to incessant or total sh ut - down of such facilities. Power generated using biomass - based renewable energy technologies is a promising option in limiting the coun - try’s dependence on fossil energy for power generation. The most important part of this option is on - site power generation via mini - grid systems. The power thus produced is utilized with the excess being fed into the national grid based on Feed - in - Tariff (F.i.T.) requirements and techni - calities. The important factors to be considered in the propagation of a mini - g rid option are ex - amined in this study. Furthermore, the study shows that about 1.3 TWh of electricity can be gener - ated from the 1.8 million tonnes per year of wood waste produced by the lumber industry in Nige - ria. Power generation through the utiliza tion of biomass has however proved to be a possible path in achieving economic, social and environmental sustainability in the country. Economic studies show that for small - scale power generation, internal combustion engines and Stirling engines are econom ically feasible. Steam turbines and gas turbines are mostly used in medium/large - scale biomass power generators, especially in proximity to biomass waste resources. Micro gas turbine power technology can also be applied on a small scale despite its high to tal investment capital.

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  • 43.
    Oluoti, Kehinde
    et al.
    University of Borås, Faculty of Textiles, Engineering and Business.
    Pettersson, Anita
    Richards, Tobias
    University of Borås, Faculty of Textiles, Engineering and Business.
    Investigating the morphology and reactivity of chars from Triplochiton scleroxylon pyrolysed under varied conditions2016In: Bioresource technology, E-ISSN 3736-3751, Vol. 208, p. 94-99Article in journal (Refereed)
    Abstract [en]

    The astronomical increase in global energy demand makes locating energy sources other than fossil fuels worthwhile. The use of tropical biomass wood waste as a renewable energy source was investigated in this study. The thermal conversion analysis of Albizia gummifera (ayinre) was carried out in a thermobalance reactor via steam gasification under varying temperature (700 to 1000 °C) and steam partial pressure (0.020 to 0.050 MPa). The experimental data was evaluated using three gas-solid reaction models. The modified volume reaction model (mVRM) gave the overall highest coefficient of determination (0.9993) and thereby the best conversion prediction. The observed char activation constant rates (from paired reaction conditions) indicated, on average, an increase in reactivity as the parameters increased. The results showed that the activation energy of the mVRM gave the lowest value (32.54 kJ/mpI) compared with those of the shrinking core model (SCM) and the volume reaction model (VRM) (49.29 and 49.89 kJ/mol, respectively).

  • 44.
    Oluoti, Kehinde
    et al.
    University of Borås, School of Engineering.
    Richards, Tobias
    University of Borås, School of Engineering.
    Doddapaneni, Tharaka
    Kanagasabapathi, DhipanKumar
    Evaluation of the Pyrolysis and Gasification Kinetics of Tropical Wood Biomass2014In: Bioresource Technology, ISSN 0960-8524, E-ISSN 1873-2976, Vol. 9, no 2, p. 2179-2190Article in journal (Refereed)
    Abstract [en]

    Two tropical biomass species, teak (Tectona grandis) and obobo (Guarea thompsonii), were obtained in the form of sawmill waste from Nigeria and evaluated to determine their potential for gasification. Pyrolysis and gasification kinetics of the samples were investigated using a thermogravimetric analyser (TGA) at temperatures of 900 oC and 1,000 oC. Four iso-conversional methods, one peak temperature method, and two model-fitting methods were employed to determine the kinetic parameters, i.e. the apparent activation energy Ea, and pre-exponential factor A. Values of the gasification kinetic rate constant K were determined using two gas-solid reaction models: the volumetric reaction model (VRM) and the shrinking core model (SCM). The values obtained for all three kinetic parameters showed good agreement with values derived for samples of non-tropical wood.

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  • 45.
    Pervez, Md. Nahid
    et al.
    University of Borås, Faculty of Textiles, Engineering and Business.
    Mahboubi, Amir
    University of Borås, Faculty of Textiles, Engineering and Business.
    Uwineza, Clarisse
    University of Borås, Faculty of Textiles, Engineering and Business.
    Zarra, T
    Sanitary Environmental Engineering Division (SEED), Department of Civil Engineering, University of Salerno, via Giovanni Paolo II 132, 84084 Fisciano, SA, Italy.
    Belgiorno, V
    Sanitary Environmental Engineering Division (SEED), Department of Civil Engineering, University of Salerno, via Giovanni Paolo II 132, 84084 Fisciano, SA, Italy.
    Naddeo, V
    Sanitary Environmental Engineering Division (SEED), Department of Civil Engineering, University of Salerno, via Giovanni Paolo II 132, 84084 Fisciano, SA, Italy.
    Taherzadeh, Mohammad J
    University of Borås, Faculty of Textiles, Engineering and Business.
    Factors influencing pressure-driven membrane-assisted volatile fatty acids recovery and purification: A review2022In: Science of the Total Environment, ISSN 0048-9697, E-ISSN 1879-1026, Vol. 817Article, review/survey (Refereed)
    Abstract [en]

    Volatile fatty acids (VFAs) are building block chemicals that can be produced through bioconversion of organic waste streams via anaerobic digestion as intermediate products. Purified VFAs are applicable in a wide range of industrial applications such as food, textiles, cosmetics, pharmaceuticals etc. production. The present review focuses on VFAs recovery methods and technologies such as adsorption, distillation, extraction, gas stripping, esterification and membrane based techniques etc., while presenting a discussion of their pros and cons. Moreover, a great attention has been given to the recovery of VFAs through membrane filtration as a promising sustainable clarification, fractionation and concentration approach. In this regard, a thorough overview of factors affecting membrane filtration performance for VFAs recovery has been presented. Filtration techniques such as nanofiltration and reverse osmosis have shown to be capable of recovering over 90% of VFAs content from organic effluent steams, proving the direct effect of membrane materials/surface chemistry, pore size and solution pH in recovery success level. Overall, this review presents a new insight into challenges and potentials of membrane filtration for VFAs recovery based on the effects of factors such as operational parameters, membrane properties and effluent characteristics.

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  • 46.
    Pettersson, Anita
    University of Borås, School of Engineering.
    Characterisation of Fuels and Fly Ashes from Co-Combustion of Biofuels and Waste Fuels in a Fluidised Bed Boiler. A Phosphorus and Alkali Perspective2008Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    In the efforts to create sustainable production of heat and power and to reduce the net CO2 emissions to the atmosphere, alternative fuels are today being utilised. These fuels are, for example, biofuels and waste derived fuels such as different residues from the agricultural sector and the pulp and paper industry, municipal sewage sludge and municipal sorted solid waste. These fuels put new demands on the combustion facilities due to their chemical composition and this in turn calls for methods of prediction for the evaluation of their combustion behaviour. Most significant for the majority of these fuels are the high alkali and chlorine concentrations which cause bed agglomeration, deposit formation and corrosion on heat transfer surfaces. These problems can be solved if sufficient knowledge is obtained of the specific fuel or fuel mix. In this work, chemical fractionation, a step by step leaching method, was used on fuels, fuel mixes and fly ashes from co-combustion in a fluidised bed combustor. In addition, XRD and SEM-EDX were used for the fuel and fly ash characterisation. Different alkali chloride reducing additives i.e. kaolin, zeolites and sulphur were investigated as was the influence of various bed materials: silica sand, olivine sand and blast furnace slag (BFS). Some of the new, alternative fuels, such as municipal sewage sludge and meat and bone meal (MBM) contain high concentrations of phosphorus which is a very important nutrient essential in many biological processes. Phosphorus rock used as raw material in the phosphate industry is a depleting natural resource estimated to last for only 30-200 years according to different sources. The combustion of municipal sewage sludge enriches the phosphorus in the ashes while hazardous components such as pathogens and organic pollutants are rendered harmless after combustion. However, toxic heavy metals are also enriched in the ashes. One aim of the work was to find a sufficiently effective and low cost method for phosphorus extraction from fly ashes derived from municipal sewage sludge combustion. Two types of municipal sewage sludges were investigated using different chemicals for the phosphorus cleaning step in the waste water treatment plants. The first sewage sludge derived from a plant using iron sulphate as flocculant to precipitate phosphorus as iron phosphate. The second sludge meanwhile came from a plant using aluminium sulphate as flocculant to precipitate phosphorus as aluminium phosphate. Both sewage sludges were dewatered prior to combustion and co-combusted with wood pellets. At pH 1 nearly all the phosphorus was released from the fly ash derived from the sewage sludge where aluminium sulphate was used as a phosphorus precipitation agent. Iron sulphate as precipitant inhibited the phosphorus extraction from the ashes, resulting in only 50-80% of the phosphorus being released. Furthermore, the mobility of heavy metals to the leachates was investigated to establish whether the leachates were suitable as fertilisers. Only minor fractions of Pd, Hg, Cr, Cu, Mn, Co, Ni, As, Sb, V and Zn were found in the leachates, all well within the legislated limitations for fertilisers. However, one exception was Cd that was nearly totally dissolved in the leachate. Thus a decadmiation of the leachate is necessary prior to any utilisation of the ashes and reuse of phosphorus as fertiliser.

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  • 47.
    Pettersson, Anita
    et al.
    University of Borås, School of Engineering.
    Herstad Svärd, Solvie
    Moradian, Farzad
    University of Borås, School of Engineering.
    Slaktavfall och kadaver förbättrar förbränningsmiljön vid avfallsförbränning i BFB-pannor- ett Waste Refinery projekt2012In: Återvinnare för industrin 2012Article in journal (Other (popular science, discussion, etc.))
    Abstract [sv]

    Kadaver och visst slakteriavfall är klassat med smittorisk sedan utbrottet av ”galna ko-sjukan” på 1990-talet. Detta betyder att det måste behandlas termiskt t.ex. brännas. I början av 2000-talet togs det därför fram en metod i Sverige för att bearbeta de animaliska restprodukterna till ett biobränsle för energiproduktion. Men vilka krav ställer det på pannorna?

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  • 48.
    Pettersson, Anita
    et al.
    University of Borås, School of Engineering.
    Moradian, Farzad
    University of Borås, School of Engineering.
    Niklasson, Fredrik
    Herstad Svärd, Solvie
    Richards, Tobias
    University of Borås, School of Engineering.
    Examples of Full scale tests on BFB Waste to Energy boilers (WtE) with direct impact on the future operation of the facility2012Conference paper (Other academic)
    Abstract [en]

    The growing problem with municipal solid waste has helped to accelerate de development of Waste to Energy plants (WtE). However, WtE-plants have problems with agglomeration, deposition and corrosion. And at the same time new waste streams are considered for combustion. Co-combustion has sometimes proven to have positive effects on the combustion environment. In this project full scale tests were performed on two twin 20 MWth WtE Bubbling Fluidized Bed (BFB) boilers in Borås, Sweden. The aim of the research was to investigate if a lowered bed temperature by means of flue gas recirculation or addition of animal waste to the normal waste mix (NWM) could improve the boiler performance. The bed temperature was decreased from 870°C, the boiler design temperature, to around 750°C. The animal waste is a pumpable slurry consisting of crushed carcasses and slaughterhouse waste classified with risk of infection because of BSE (Bovine spongiforme encephalopathy or the mad cow disease). The result shoved both decreased deposit formation rate and decreased agglomeration tendency of the bed. And in the case with animal waste addition the NOx emission was reduced with 50% compared to ordinary performance. Furthermore the ammonia addition for NOx reduction was also cut by half in this case.

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  • 49.
    Pettersson, Anita
    et al.
    University of Borås, School of Engineering.
    Niklasson, Fredrik
    Moradian, Farzad
    University of Borås, School of Engineering.
    Reduced bed temperature in a commercial waste to energy boiler: Impact on ash and deposit formation2013In: Fuel processing technology, ISSN 0378-3820, E-ISSN 1873-7188, Vol. 105, p. 28-36Article in journal (Refereed)
    Abstract [en]

    Waste combustion for power production is associated with many problems due to the composition and inhomogeneity of the fuel stream. A reduction of alkaline and chlorine products in the superheater region should ease these problems significantly. Ashes and deposits from different combustion tests in a commercial 20 MWth bubbling fluidised bed (BFB) boiler were characterised by XRD and SEM-EDX. The fuel combusted was a mix of sorted municipal solid waste (MSW) and industrial waste, often referred to as RDF (refuse derived duel). These waste fuels often contain more alkali and chlorine than does biomass and are therefore considered risky fuels prone to causing bed agglomeration, deposit formation, and corrosion. The aim of this study was to investigate whether a lowered bed temperature could change alkali and chlorine distribution in the boiler to reduce corrosion and deposit formation. The boiler used was designed for a bed temperature in the range of 850–900 °C, which in this investigation was decreased by approximately 150 °C. Data were collected through deposit measurements and solid sampling. The lowered bed temperature resulted in reduced demand for fresh sand, decreased agglomeration, and reduced rates of deposit formation.

  • 50.
    Pettersson, Anita
    et al.
    University of Borås, School of Engineering.
    Zevenhoven, Maria
    Steenari, Britt-Marie
    Åmand, Lars-Erik
    Application of chemical fractionation methods for characterisation of biofuels, waste derived fuels and CFB co-combustion fly ashes2008In: Fuel, ISSN 0016-2361, E-ISSN 1873-7153, Vol. 87, no 15-16, p. 3183-3193Article in journal (Refereed)
    Abstract [en]

    In the important efforts to decrease the net CO2 emissions to the atmosphere, new, alternative fuels are being included in the fuel mixes used in utility boilers. However, these fuels have ash properties that are different from those of the traditionally used fuels and in some cases technical problems, such as ash fouling and corrosion occur due to this. Therefore, diagnostic and predictive methods are developed and used to avoid such problems. Determination of the chemical association forms of important elements, such as potassium and sodium, in the fuel by chemical fractionation is a method well defined for coal and biofuels, such as wood pellets, bark and forest residues. Chemical fractionation is a step by step leaching method extracting water soluble salts in the first step, ion exchangeable elements, such as organically associated sodium, calcium and magnesium in the second step and acid soluble compounds such as carbonates and sulfates in the third step. The solid residue fraction consists of silicates, oxides, sulfides and other minerals. The compound extracted in the two first steps is considered reactive in the combustion with a few exceptions. In this work, it has been applied to some waste fuels, i.e. sewage sludge, straw and refuse derived fuel (RDF), as well as to coal and wood. The present work also includes results from combustion tests in a fluidised bed boiler where three blends of the investigated fuels were used. The fractionation results for the fuel blends are weighted results of the fractionations of the pure fuels discussed above which are compared with fractionations of their corresponding fly ashes. The co-combustion strategy gave very good results in reducing ash problems. Possible chemical mechanisms involved are discussed in the article.

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