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  • 51.
    Li, Hailong
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Larsson, Eva K.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Thorin, Eva
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Dahlquist, Erik
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Yu, Xinhai
    E China Univ Sci & Technol, Shanghai, Peoples R China.
    Feasibility study on combining anaerobic digestion and biomass gasification to increase the production of biomethane2015Inngår i: Energy Conversion and Management, ISSN 0196-8904, E-ISSN 1879-2227, Vol. 100, s. 212-219Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    There is a rapid growing interest in using biomethane as fuel for transport applications. A new concept is proposed to combine anaerobic digestion and biomass gasification to produce biomethane. H-2 is separated from the syngas generated by biomass gasification in a membrane system, and then is used to upgrade raw biogas from anaerobic digestion. Simulations have been conducted based on the real operation data of one full scale biogas plant and one full scale biomass gasification plant in order to investigate the feasibility of the new concept. Results show that although less power and heat are generated compared to the gasification plant, which results in a lower overall efficiency, much more biomethane can be produced than the biogas plant; and the new concept can achieve a higher exergy efficiency. Due to the increasing price of biomethane, the novel concept demonstrates a big potential of income increase. For example, at a biomethane price of 12.74SEK/kg, the annual income can be increased by 53% compared to the total income of the biogas and gasification plant. (C) 2015 Elsevier Ltd. All rights reserved.

  • 52.
    Li, Hailong
    et al.
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling. Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Lindmark, Johan
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling. Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Nordlander, Eva
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling. Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Thorin, Eva
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling. Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Dahlquist, Erik
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling. Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Zhao, Li
    Tianjin University, China.
    Using the solid digestate from a wet anaerobic digestion process as an energy resource2013Inngår i: Energy technology, ISSN 2194-4296, Vol. 1, nr 1, s. 94-101Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The wet anaerobic digestion process is a widely used method to produce biogas from biomass. To avoid the risks involved with using the digestion waste as a fertilizer, this work investigates the possibilities to use the solid digestate as an energy resource to produce heat and electricity, which could save some energy currently consumed by the plant and, therefore, may increase the overall efficiency of a biogas plant. Simulations were conducted based on real data from the Växtkraft biogas plant in Västerås, Sweden as a case study. Results show that it is necessary to dry the solid digestate before combustion and include flue-gas condensation to recover enough heat for the drying process. When a steam turbine cycle is integrated, the generated electricity could cover 13–18 % of the total electricity consumption of the plant, depending on the degree of dryness. In addition, reducing the digestion period can increase the carbon content (ultimate analysis), the heating value, and the mass flow of the solid digestate. As a result, the production of electricity and heat is augmented in the steam turbine cycle. However, the production of biogas is reduced. Therefore, a comprehensive economic evaluation is suggested to optimize a biogas plant that uses the solid digestate from a wet anaerobic digestion process as an energy resource.

  • 53.
    Li, Hailong
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Wang, Bin
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Yan, Jinyue
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. KTH Royal Institute of Technology, Stockholm, Sweden.
    Salman, Chaudhary Awais
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Thorin, Eva
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Schwede, Sebastian
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Performance of flue gas quench and its influence on biomass fueled CHP2019Inngår i: Energy, ISSN 0360-5442, E-ISSN 1873-6785, Vol. 180, s. 934-945Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    For biomass/waste fueled power plants, stricter regulations require a further reduction of the negative impacts on the environment caused by the release of pollutants and withdrawal of fresh water externally. Flue gas quench (FGQ) is playing an important role in biomass or waste fueled combined heat and power (CHP) plants, as it can link the flue gas (FG) cleaning, energy recovery and wastewater treatment. Enhancing water evaporation can benefit the concentrating of pollutant in the quench water; however, when FG condenser (FGC) is not in use, it results in a large consumption of fresh water. In order to deeply understand the operation of FGQ, a mathematic model was developed and validated against the measurements. Based on simulation results key parameters affecting FGQ have been identified, such as the flow rate and temperature of recycling water and the moisture content of FG. A guideline about how to reduce the discharge of wastewater to the external and the withdrawal of external water can be proposed. The mathematic model was also implemented into an ASPEN Plus model about a CHP plant to assess the impacts of FGQ on CHP. Results show that when the FGC was running, increasing the flow rate and decreasing the temperature of recycling water can result in a lower total energy efficiency. 

  • 54.
    Li, W.
    et al.
    College of Chemical Engineering, Beijing University of Chemical Technology, Beijing, China.
    Khalid, H.
    College of Chemical Engineering, Beijing University of Chemical Technology, Beijing, China.
    Zhu, Z.
    College of Chemical Engineering, Beijing University of Chemical Technology, Beijing, China.
    Zhang, R.
    Department of Biological and Agricultural Engineering, University of California, Davis, CA, United States.
    Liu, G.
    College of Chemical Engineering, Beijing University of Chemical Technology, Beijing, China.
    Chen, Chang
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. College of Chemical Engineering, Beijing University of Chemical Technology, Beijing, China.
    Thorin, Eva
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Methane production through anaerobic digestion: Participation and digestion characteristics of cellulose, hemicellulose and lignin2018Inngår i: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 226, s. 1219-1228Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Lignocellulosic biomass is the most abundant natural resource with high biomethane potential. However, complex structure of lignocellulosic biomass has hampered the efficient utilization of this bioresource. Previous studies have investigated the overall anaerobic digestion performance of lignocellulosic biomass, but the individual participation of each lignocellulosic component during anaerobic digestion remained unclear. Thus, this study investigated the methane production characteristics of cellulose, hemicellulose, lignin and their mixtures along with the microbial communities involved in anaerobic digestion. The results showed that the biomethane potential of cellulose was higher than that of hemicellulose; however, hemicellulose was hydrolysed more quickly than cellulose, while lignin was very difficult to be digested. The higher concentrations of acetic, n-butyric and n-valeric acids hydrolysed from the hemicellulose resulted in a lower pH and more severe inhibition on methane production than that of cellulose, and the methanogenesis gradually recovered after pH adjustment. The co-digestion of cellulose and hemicellulose increased the methane yield and biodegradability compared to mono-digestions. The addition of lignin to cellulose brought more significant decrease in the methane yield of cellulose than that of hemicellulose. Substrate-related bacteria such as Clostridium sensu stricto, Lutaonella, Cloacibacillus and Christensenella showed higher relative abundance in cellulose digestate, and sugar-fermenting bacteria such as Saccharofermentans, Petrimonas and Levilinea were more rich in the digestate of hemicellulose. Moreover, methanogenic Methanospirillum and Methanothrix likely contributed to the methane production of cellulose, while aciduric methanogens from Methanobrevibacter, Methanomassiliicoccus, Methanobacterium and Methanoculleus contributed to that of hemicellulose. This study provides a deeper understanding of the mechanism in the bioconversion of lignocellulosic biomass during anaerobic digestion.

  • 55.
    Lindmark, Johan
    et al.
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling.
    Bel Fdhila, Rebei
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling.
    Thorin, Eva
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling.
    ON MODELLING THE MIXING IN A DIGESTER FOR BIOGAS PRODUCTION2009Inngår i: / [ed] I. Troch, F. Breitenecker, 2009Konferansepaper (Annet vitenskapelig)
    Abstract [en]

    At the Vaxtkraft biogas plant the mixing is produced by pumping in biogas and releasing it at the bottom. The mixing inside the digester of a biogas plant is important for good biogas production and since it is complicated to study the mixing inside the digester while it is in operation, this study is based on numerical simulations using a computational fluid dynamic finite volume code. To study the mixing dynamics, five different flow rates of gas (air) injections ranging from 0.1 to 0.6kg/s were simulated. These gas flow rates produced an average liquid speed in the digester between 0.10 and 0.22 m/s. The liquid recirculation impact on the mixing was investigated through the simulation of a case where it is combined with the lowest gas injection flow rate. The results from the simulation suggest that the liquid outlet is situated too close to the gas injection, resulting in energy losses in form of diminished mixing of the digester. A complete redesign of the digester is needed to seriously overcome the mixing limitation.

  • 56.
    Lindmark, Johan
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Eriksson, Per
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik.
    Thorin, Eva
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    The effects of different mixing intensities during anaerobic digestion of the organic fraction of municipal solid waste2014Inngår i: Waste Management, ISSN 0956-053X, E-ISSN 1879-2456, Vol. 34, nr 8, s. 1391-1397Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Mixing inside an anaerobic digester is often continuous and is not actively controlled. The selected mixing regime can however affect both gas production and the energy efficiency of the biogas plant. This study aims to evaluate these effects and compare three different mixing regimes, 150 RPM and 25 RPM continuous mixing and minimally intermittent mixing for both digestion of fresh substrate and post-digestion of the organic fraction of municipal solid waste. The results show that a lower mixing intensity leads to a higher biogas production rate and higher total biogas production in both cases. 25 RPM continuous mixing and minimally intermittent mixing resulted in similar biogas production after process stabilization, while 150 RPM continuous mixing resulted in lower production throughout the experiment. The lower gas production at 150 RPM could not be explained by the inhibition of volatile fatty acids. Cumulative biogas production until day 31 was 295. ±. 2.9, 317. ±. 1.9 and 304. ±. 2.8. N. ml/g VS added during digestion of fresh feed and 113. ±. 1.3, 134. ±. 1.1 and 130. ±. 2.3. N. ml/g VS added during post digestion for the 150 RPM, 25 RPM and minimally mixed intensities respectively. As well as increasing gas production, optimal mixing can improve the energy efficiency of the anaerobic digestion process.

  • 57.
    Lindmark, Johan
    et al.
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling.
    Lagerkvist, Anders
    Luleå University of Technology, Division of Waste Science and Technology.
    Nilsson, Erik
    Andreas, Lale
    Luleå University of Technology, Division of Waste Science and Technology.
    Carlsson, My
    Luleå University of Technology, Division of Waste Science and Technology.
    Thorin, Eva
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling.
    Dahlquist, Erik
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling.
    Pre-treatment of Substrate for Increased Biogas ProductionManuskript (preprint) (Annet vitenskapelig)
    Abstract [en]

    The full biogas potential of most organic material cannot be exploited with today’s technology. The complex structures of the organic materials are broken down too slowly and the nutrients cannot become biologically available during the relatively short retention time of most digesters. This means that a lot of the bound energy in the organic material leaves the biogas plant with the liquid digestate. There is a possibility to increase the efficiency of the process by pre-treating the material before digestion. This paper explores a pre-treatment of ley crop silage using electrical fields, known as electroporation (EP). Different settings of the EP equipment were tested and the results were analysed using a batch digestion setup. The results from the experiments show that there is a possibility to double the biogas production at typical retention times of a CSTR. The energy balance of the EP equipment suggests that the pre-treatment yield is around 2-6 times larger than the energy input to the process, i.e. energy in the form of methane.  

  • 58.
    Lindmark, Johan
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Lagerkvist, Anders
    Division of Waste Science and Technology, Luleå University of Technology, Luleå, Sweden.
    Nilsson, Erik
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Carlsson, My
    AnoxKaldnes AB, Lund, Sweden.
    Thorin, Eva
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Dahlquist, Erik
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Evaluating the effects of electroporation pre-treatment on the biogas yield from ley crop silage.2014Inngår i: Applied Biochemistry and Biotechnology, ISSN 0273-2289, E-ISSN 1559-0291, Vol. 174, nr 7, s. 2616-2625Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Exploiting the full biogas potential of some types of biomass is challenging. The complex structures of lignocellulosic biomass are difficult to break down and thus require longer retention times for the nutrients to become biologically available. It is possible to increase the digestibility of the substrate by pre-treating the material before digestion. This paper explores a pre-treatment of ley crop silage that uses electrical fields, known as electroporation (EP). Different settings of the EP equipment were tested, and the results were analyzed using a batch digestion setup. The results show that it is possible to increase the biogas yield with 16 % by subjecting the substrates to 65 pulses at a field strength of 96 kV/cm corresponding to a total energy input of 259 Wh/kg volatile solid (VS). However, at 100 pulses, a lower field strength of 48 kV/cm and the same total energy input, no effects of the treatment were observed. The energy balance of the EP treatment suggests that the yield, in the form of methane, can be up to double the electrical energy input of the process.

  • 59.
    Lindmark, Johan
    et al.
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling.
    Leksell, Niklas
    Växtkraft.
    Schnürer, Anna
    SLU.
    Thorin, Eva
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling.
    Effects of mechanical pre-treatment on the biogas yield from ley crop silage2012Inngår i: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 97, s. 498-502Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Previous studies on substrates for biogas production have shown that different types of pre-treatments make the material more accessible for microbial degradation by breaking down the complex structure of the organic material, thereby increasing their potential for gas production. In this paper, two different mechanical pre-treatment apparatus, i.e. a Grubben deflaker (Gd) and a Krima disperser (Kd), were tested in a full scale setup to evaluate their effects on ley crop silage. The treatments were investigated with regard to their effects on particle size, methane potential, capacity and energy balance. The results after 115 days of incubation in a batch assay show that methane production increased by 59% and 43% respectively after grinding with Gd and Kd. In both treatments, 90% of the ley crop was ground to particles of less than 2 mm and more than 50% of the sample was reduced to particles smaller than 0.125 mm. The energy balance was positive for Gd and around the break-even point for Kd. Analysis of the setup showed that Kd had almost twice the capacity of the Gd. If installed in the co-digestion biogas plant Vaxtkraft in Vasteras, Sweden, the Gd and Kd could increase annual biogas yields by 790 MW h and 585 MW h respectively. (c) 2012 Elsevier Ltd. All rights reserved.

  • 60.
    Lindmark, Johan
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik.
    Nilsson, Erik
    Lagerkvist, Anders
    Luleå University of Technology, Division of Waste Science and Technology.
    Andreas, Lale
    Luleå University of Technology, Division of Waste Science and Technology.
    Carlsson, My
    Luleå University of Technology, Division of Waste Science and Technology.
    Thorin, Eva
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik.
    Dahlquist, Erik
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik.
    Pretreatment of Substrate for Increased Biogas Production2010Konferansepaper (Fagfellevurdert)
  • 61.
    Lindmark, Johan
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Thorin, Eva
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Bel Fdhila, Rebei
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. ABB AB, Corporate Research, Västerås.
    Dahlquist, Erik
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Effects of mixing on the result of anaerobic digestion: Review2014Inngår i: Renewable & Sustainable Energy Reviews, ISSN 1364-0321, Vol. 40, s. 1030-1047Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Mixing in an anaerobic digester keeps the solids in suspension and homogenizes the incoming feed with the active microbial community of the digester content. Experimental investigations have shown that the mixing mode and mixing intensity have direct effects on the biogas yield even though there are conflicting views on mixing design. This review analyzes and presents different methods to evaluate the mixing in a digester (chemical and radioactive tracers and laboratory analysis), tools for digester design (computational fluid dynamics and kinetic modeling) and current research on the effects of mixing on the anaerobic digestion process. Empirical data on experiments comparing different mixing regimes have been reviewed from both a technical and microbial standpoint with a focus both on full scale digesters and in lab-scale evaluations. Lower mixing intensity or uneven mixing in the anaerobic digestion process can be beneficial during the startup phase to allow for methanogenic biomass growth and alleviate process instability problems. Intermittent mixing has been shown to be able to yield a similar gas production as continuous mixing but with the possibility to reduce the maintenance and energy demands of the process. Problems often experienced with experimental design include the effect of mixing on the solids retention time, and measurement of steady state gas production because of startup instabilities. Further research should be aimed at studying the effects of mixing on a chemical and microbial level and on the different stages of anaerobic digestion (hydrolysis, acidogenesis, acetogenesis and methanogenesis). The focus should be on the effects of mixing on a multiple stage digestion process and also finding new methods to evaluate the effects of mixing in the one stage digestion process rather than evaluating a wider range of mixing modes, intensities and substrates.

  • 62.
    Lindmark, Johan
    et al.
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling.
    Thorin, Eva
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling.
    Bel Fdhila, Rebei
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling.
    Dahlquist, Erik
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling.
    PROBLEMS AND POSSIBILITIES WITH THE IMPLEMENTATION OF SIMULATION AND MODELING AT A BIOGAS PLANT2012Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Advanced models are being developed for the anaerobicdigestion (AD) process. These models can be used to control and optimize industrial size biogas plant to reach their full potential. There are many models available for different types of implementations. However, many of the published models demands extensive chemical analysis that might not be practically and economically viable in industry. Sampling routines at six Swedish biogas plants was compiled for comparison with the demand of input in published modeling approaches. The gap between the models and practices in industry has to come together through model simplification and extended sampling routines. Chemical oxygen demand (COD) for example is not a commonly used analysis in Swedish biogas plants but which is regularly used to model the AD. Knowledge of the biochemical processes in AD built in to a model can help operators increase the biogas yield of the plant without jeopardizing the production. There is a lack of robust online measurement equipment today to be able to have reliable online models for operational support but near infrared spectroscopy (NIR) is a promising technology for online measuring of a series of different characteristics that could make modeling more interesting for the AD industry. The mixing has as of yet not been devoted much attention to when modeling the process.

  • 63.
    Lindmark, Johan
    et al.
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling.
    Thorin, Eva
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling.
    Kastensson, Jan
    Mercatus Engn AB.
    Pettersson, Carl-magnus
    Svensk Växtkraft AB.
    Membrane filtration of process water at elevated temperatures: a way to increase the capacity of a biogas plant2011Inngår i: Desalination, ISSN 0011-9164, E-ISSN 1873-4464, Vol. 267, nr 2-3, s. 160-169Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

     Waste water from a biogas process is often recirculated and mixed with the incoming organic material to produce a feed for the digester. The dry matter (DM) content of the final mixture should be as high as possible to maximise the capacity of the plant without exceeding the capability of the pumps. This means that the DM content of the recirculated process water has a large impact on the amount of substrate that can be processed. Experiments to reduce the dry matter content of the recirculated process water were carried out using a ceramic ultrafiltration (UF) membrane. The influence on the flux through the membrane and the separation efficiency at different operation temperatures, 70°C, 90°C and 110°C, were investigated. Higher temperatures resulted in increased flux/flow through the membrane. The DM content was reduced from 4% to 1.6%, corresponding to a 29 % increase of new material that could be added to the process. The energy required to heat the membrane when using heat recovery is small compared to the energy of the methane produced from the additional added substrate. The lifespan of the membranes and uncertainties in the substrate DM content are showed to be important for the economic result.

  • 64.
    Lõõnik, Jaan
    et al.
    Estonian Regional and Local Development Agency (ERKAS).
    Saarepera, Reljo
    Estonian Regional and Local Development Agency (ERKAS).
    Käger, Maarja
    Estonian Regional and Local Development Agency (ERKAS).
    Sogenbits, Thea
    Estonian Regional and Local Development Agency (ERKAS).
    Freienthal, Priit
    Estonian Regional and Local Development Agency (ERKAS).
    Thorin, Eva
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik. Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Song, Han
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik. Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Guziana, Bozena
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik. Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Jääskeläinen, Ari
    The Municipal Federation of Savonia University of Applied Sciences (SUA).
    Eskelinen, Tuomo
    The Municipal Federation of Savonia University of Applied Sciences (SUA).
    Kajanus, Miika
    The Municipal Federation of Savonia University of Applied Sciences (SUA).
    Huopana, Tuomas
    University of Eastern Finland (UEF) .
    Niska, Harri
    University of Eastern Finland (UEF) .
    den Boer, Emilia
    Wroclaw University of Technology / Institute of Environmental Protection Engineering.
    den Boer, Jan
    Wroclaw University of Technology / Institute of Environmental Protection Engineering.
    Szpadt, Ryszard
    Wroclaw University of Technology / Institute of Environmental Protection Engineering.
    Behrendt, Anna
    Ostfalia University of Applied Sciences, Fachhochschule Braunschweig / Wolfenbüttel (BUA).
    Vasilic, Dejan
    Ostfalia University of Applied Sciences, Fachhochschule Braunschweig / Wolfenbüttel (BUA).
    Ahrens, Thorsten
    Ostfalia University of Applied Sciences, Fachhochschule Braunschweig / Wolfenbüttel (BUA).
    Anne, Olga
    Klaipeda University (KLU).
    Balčiũnas, Arũnas
    Klaipeda University (KLU).
    GUIDELINE ON ACTION PLANS AND STRATEGIES TO MOBILIZE WASTE-TO-ENERGY PRODUCTION: REMOWE report,  Report no: 4.3.1, December 20122012Rapport (Fagfellevurdert)
  • 65.
    Lönnqvist, T.
    et al.
    Department of Chemical Engineering and Technology, Division of Energy Processes, Royal Institute of Technology – KTH.
    Sandberg, T.
    Department of Industrial Economics and Management, Royal Institute of Technology – KTH.
    Birbuet, J. C.
    Centre for Promotion of Sustainable Technologies, CPTS, San Jorge, La Paz, Bolivia.
    Olsson, J.
    Espinosa, C.
    Centre for Promotion of Sustainable Technologies, CPTS, Prolongación Cordero 220, San Jorge, La Paz, Bolivia.
    Thorin, Eva
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Grönkvist, S.
    Department of Chemical Engineering and Technology, Division of Energy Processes, Royal Institute of Technology – KTH.
    Gómez, M. F.
    Energy, Materials, Environment Laboratory, Department of Chemical Engineering, University of la Sabana, Bogotá, Colombia.
    Large-scale biogas generation in Bolivia – A stepwise reconfiguration2018Inngår i: Journal of Cleaner Production, ISSN 0959-6526, E-ISSN 1879-1786, Vol. 180, s. 494-504Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Renewable energy is well recognized not only as resource that helps to protect the environment for future generations but also as a driver for development. Waste-to-energy systems can provide renewable energy and also improve sustainability in waste management. This article contributes a case study of stepwise reconfiguration of the waste management system in a developing country to the literature of transitions. The conditions for a systemic transition that integrates large-scale biogas generation into the waste management system have been analyzed. The method included a multi-criteria evaluation of three development steps for biogas, an economic analysis, and an institutional and organizational analysis. The results revealed economic as well as institutional and organizational barriers. Clearly, public and private sectors need to engage in sustainability. There is also a lack of pressure – mainly because of fossil fuel subsidies – that prevents a transition and creates a lock-in effect. To break the lock-in effect the municipality's institutional capacity should be strengthened. It is possible to strengthen biogas economically by integrated waste management services and sales of biofertilizer. A stepwise reconfiguration would be initiated by adopting technologies that are already established in many developed countries but are novelties in a Bolivian context – as a response to sustainability challenges related to waste management. The article focuses on the main challenges and the potential for biogas technology in Bolivia and a pathway towards a new, more sustainable system is suggested.

  • 66.
    Lönnqvist, Tomas
    et al.
    KTH, Energi och klimatstudier, ECS.
    Olsson, Jesper
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. MDH.
    Espinosa, Cecilia
    Center for Promotion of Sustainable Technology (CPTS).
    Birbuet, Juan Cristóbal
    Center for Promotion of Sustainable Technology (CPTS).
    Silveira, Semida
    KTH.
    Dahlquist, Erik
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Thorin, Eva
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Persson, Per-Erik
    VAFAB Miljö AB.
    Lindblom, Sandra
    VAFAB Miljö AB.
    Khatiwada, Dilip
    KTH.
    The potential for waste to biogas in La Paz and El Alto in Bolivia2013Inngår i: 1st International Water Association Conference on HolisticSludge Management, 2013, Västerås Sweden, 2013Konferansepaper (Fagfellevurdert)
    Abstract [en]

    In the cities of La Paz and El Alto, 573 tons of organic material are disposed in landfills every day. These residues can be used to produce biogas and recycle nutrients, thus alleviating environmental impacts related to waste management. Technical solutions are evaluated through a multicriteria analysis with the purpose of defining a strategy for implementing waste-to-biogas in the two cities. As a result, the development for waste-to-biogas-system is defined in three steps. Step 1 consists of an active extraction system of landfill gas in the already existing landfills. Step 2 implies the establishment of a dry-digestion biogas facility based on present waste collection practices, that is, not segregated waste. Step 3 consists of a biogas plant using dry digestion for processing source segregated bio-waste. The economic feasibility of these three steps is evaluated. Despite prevailing fossil fuels subsidies in the country, implementing waste-to-biogas turn out feasible in the country provided the digestate is commercialized as bio-fertilizer or erosion control material and additional services such as waste collection and deposition are computed in the total economy of the biogas production plant.

  • 67.
    Mirmoshtaghi, Guilnaz
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Li, Hailong
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Thorin, Eva
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Dahlquist, Erik
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    BIO-METHANE PRODUCTION THROUGH DIFFERENT BIOMASS GASIFIERS2013Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Considering sustainability of energy resources and environmental concerns have led to activities all over the world seeking alternatives for current methods of fuel production. Gasification of biomass to supply bio-methane is one of those options. Bio-methane is carbon neutral and meets the needs of combustion engines in vehicles.Focusing on vehicle fuel production reveals the need for wide research to understand different types of gasifiers in order to find the possibilities for more methane production.In this paper data collected from different experimental setups are summarized and analyzed.Fluidized bed gasifiers show higher methane concentrations in the produced gas while entrained flow and downdraft gasifiers may be the least suitable types for high methane yields.Heating value of the product gas and cold gas efficiency are also studied as the important parameters for evaluating the characteristics of the product gas. This analysis shows that by increasing the equivalence ratio, the heating value of the product gas decreases while the efficiency may not follow the same trend.

  • 68.
    Mirmoshtaghi, Guilnaz
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. Mälardalen Högskola.
    Li, Hailong
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Thorin, Eva
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Dahlquist, Erik
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    EVALUATION OF DIFFERENT BIOMASS GASIFICATION MODELING APPROACHES FOR FLUIDIZED BED GASIFIERS2016Inngår i: Biomass and Bioenergy, ISSN 0961-9534, E-ISSN 1873-2909, Vol. 91, s. 69-82Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    To develop a model for biomass gasification in fluidized bed gasifiers with high accuracy and generality that could be used under various operating conditions, the equilibrium model (EM) is chosen as a general and case-independent modeling method. However, EM lacks sufficient accuracy in predicting the content (volume fraction) of four major components (H2, CO, CO2 and CH4) in product gas. In this paper, three approaches—MODEL I, which restricts equilibrium to a specific temperature (QET method); MODEL II, which uses empirical correlations for carbon, CH4, C2H2, C2H4, C2H6 and NH3 conversion; and MODEL III, which includes kinetic and hydrodynamic equations—have been studied and compared to map the barriers and complexities involved in developing an accurate and generic model for the gasification of biomass.

    This study indicates that existing empirical correlations can be further improved by considering more experimental data. The updated model features better accuracy in the prediction of product gas composition in a larger range of operating conditions. Additionally, combining the QET method with a kinetic and hydrodynamic approach results in a model that features less overall error than the original model based on a kinetic and hydrodynamic approach.

  • 69.
    Mirmoshtaghi, Guilnaz
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. Mälardalen Högskola.
    Li, Hailong
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Thorin, Eva
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Dahlquist, Erik
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    THE EFFECT OF INCLUDING HYDRODYNAMICS FOR MODELING ATMOSPHERIC BUBBLING FLUIDIZED BED GASIFIERS2014Konferansepaper (Fagfellevurdert)
  • 70.
    Mirmoshtaghi, Guilnaz
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Skvaril, Jan
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Campana, Pietro Elia
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Li, Hailong
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Thorin, Eva
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Dahlquist, Erik
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    The influence of different parameters on biomass gasification in circulating fluidized bed gasifiers2016Inngår i: Energy Conversion and Management, ISSN 0196-8904, E-ISSN 1879-2227, Vol. 126, s. 110-123Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The mechanism of biomass gasification has been studied for decades. However, for circulating fluidized bed (CFB) gasifiers, the impacts of different parameters on the gas quality and gasifiers performance have still not been fully investigated. In this paper, different CFB gasifiers have been analyzed by multivariate analysis statistical tools to identify the hidden interrelation between operating parameters and product gas quality, the most influencing input parameters and the optimum points for operation. The results show that equivalence ratio (ER), bed material, temperature, particle size and carbon content of the biomass are the input parameters influencing the output of the gasifier the most. Investigating among the input parameters with opposite impact on product gas quality, cases with optimal gas quality can result in high tar yield and low carbon conversion while low tar yield and high carbon conversion can result in product gas with low quality. However using Olivine as the bed material and setting ER value around 0.3, steam to biomass ratio to 0.7 and using biomass with 3 mm particle size and 9 wt% moisture content can result in optimal product gas with low tar yield.

  • 71.
    Mirmoshtaghi, Guilnaz
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. Mälardalen Högskola.
    Skvaril, Jan
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Li, Hailong
    Thorin, Eva
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Dahlquist, Erik
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    INVESTIGATION OF EFFECTIVE PARAMETERS ON BIOMASS GASIFICATION IN CIRCULATING FLUIDIZED BED GASIFIERS2015Konferansepaper (Fagfellevurdert)
  • 72.
    Mirmoshtaghi, Guilnaz
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Skvaril, Jan
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Li, Hailong
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Thorin, Eva
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Dahlquist, Erik
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Investigation of Most Effective Parameters on Biomass Gasufication in Circulating Fluidized bed Gasifiers2015Inngår i: Forest and Plant Bioproducts Division 2015 - Core Programming Area at the 2015 AIChE Annual Meeting, 2015, s. 189-200Konferansepaper (Fagfellevurdert)
  • 73.
    Nehrenheim, Emma
    et al.
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling. Mälardalens högskola, Akademin för ekonomi, samhälle och teknik.
    Odlare, Monica
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling. Mälardalens högskola, Akademin för ekonomi, samhälle och teknik.
    Fredrik, Vallin
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling.
    Eva, Thorin
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik.
    Dahlquist, Erik
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik.
    Yan, Jinyue
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik.
    Algal blooms - an environmental problem or a potential energy resource? the potentials for algae cultivation in lake Mälaren, an eutrophicated lake in Sweden2010Konferansepaper (Fagfellevurdert)
  • 74.
    Nookuea, Worrada
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Tan, Y.
    School of Chemical Science and Engineering, Royal Institute of Technology, Stockholm, Sweden.
    Li, Hailong
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Thorin, Eva
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Yan, Jinyue
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. School of Chemical Science and Engineering, Royal Institute of Technology, Stockholm, Sweden.
    Impacts of thermo-physical properties of gas and liquid phases on design of absorber for CO2 capture using monoethanolamine2016Inngår i: International Journal of Greenhouse Gas Control, ISSN 1750-5836, E-ISSN 1878-0148, Vol. 52, s. 190-200Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Absorption of CO2 with aqueous amines in post-combustion capture is characterized as a heat and mass transfer processes with chemical reaction, which is sensitively affected by the thermo-physical properties of fluids. In order to optimize the design of the absorber of CO2 capture process, in this paper, the impacts of thermo-physical properties on the column design were investigated. Furthermore, the property impacts on the capital cost of the absorber unit were also identified and analyzed. Results show that the gas phase density has the most significant effect on the column diameter. Underestimation of the gas phase density of 10% may result in an increase of about 6% of the column diameter. For the packing height, the liquid phase density has the most significant effect. 10% underestimation of the liquid phase density may result in an increase of 8% of the packing height. Moreover, the effect from the liquid phase viscosity is also significant. For the annual capital cost, the liquid phase density also shows the most significant effect. Underestimation of the liquid phase density of 10% leads to the cost overestimation of $1.4 million for the absorption column for a 400 MW coal-fired power plant. Therefore, the development of the flue gas density model and liquid phase density and viscosity models of the aqueous amine solution with CO2 loading should be prioritized.

  • 75.
    Nookuea, Worrada
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Tan, Yuting
    Royal Inst Technol, Stockholm, Sweden.
    Li, Hailong
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Thorin, Eva
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Yan, Jinyue
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Sensitivity study of thermo-physical properties of gas phase on absorber design for CO2 capture using monoethanolamine2015Inngår i: Energy Procedia, ISSN 1876-6102, E-ISSN 1876-6102, Vol. 75, s. 2305-2310Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Absorption of CO2 with aqueous amines in post-combustion capture is characterized as mass transfer process with chemical reaction. Hydrodynamics and mass transfer in gas and liquid phases in a packed column have significant influences on absorber design especially for the design of packing height. In this paper, the sensitivity study has been conducted to investigate the impacts of gas phase density, viscosity and diffusivity on the hydrodynamics and mass transfer and further the total packing height of a countercurrent flow with random packing column, using reactive absorption process and integral rate-based models. Results show that density and diffusivity have opposite effect to viscosity. Amongst various properties, diffusivity has the most significant effect on the packing height compared to density and viscosity. Overestimation of diffusivity of 5% may result in decrease of 3.2% of packing height. Moreover, developing more accurate diffusivity model should be prioritized for more accurate absorber design. 

  • 76.
    Nookuea, Worrada
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Wang, Fu
    Tianjin University, China.
    Yang, Jie
    University of Shanghai for Science and Technology, Shanghai, China.
    Tan, Yuting
    Royal Institute of Technology, Sweden .
    Li, Hailong
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Thorin, Eva
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Yu, Xinhai
    East China University of Science and Technology, Shanghai, China.
    Yan, Jinyue
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Viscosity data of aqueous MDEA–[Bmim][BF4] solutions within carbon capture operating conditions2017Inngår i: Energy Procedia, ISSN 1876-6102, E-ISSN 1876-6102, Vol. 105, s. 4581-4586Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Post–combustion capture with chemical absorption shows higher potential for commercial scale application compared with other technologies. To capture CO2 from the industrial and power plant’s flue gases, aqueous alkanolamine solutions are widely used. However, several drawbacks from utilizing the aqueous alkanolamines such as MEA still need to be solved. For example, alkanolamine solutions require intensive energy for regeneration and cause severe corrosion to the equipment though they have high reactivity in capturing CO2. Ionic liquids have been of interest in the recent development of chemical absorption according to their unique characteristics including wide liquid range, negligible volatility and thermal stability. However, due to their high price, high viscosity and low absorption capacity compared to alkanolamines, ionic liquids are still non–desirable for industrial applications.

    One possible solution to improve the performance of ionic liquids is to use mixtures of ionic liquids and alkanolamines. For a better understanding of the absorption using the mixture of aqueous alkanolamines and ionic liquids, the knowledge of thermo–physical properties of the solutions, especially the viscosity and density are of importance. This paper reports the measured viscosity of MDEA–[Bmim][BF4] aqueous mixtures at various temperatures and concentrations. It was found that the viscosity increase with an increase in [Bmim][BF4] concentration, but decrease with an increase in temperature. Moreover, the impact of temperature on the viscosity is more significant at low temperature range.

  • 77.
    Nookuea, Worrada
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Zambrano, Jesús
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Tan, Yuting
    Royal Institute of Technology, Sweden.
    Li, Hailong
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Thorin, Eva
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Yan, Jinyue
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. Royal Institute of Technology, Stockholm, Sweden.
    Comparison of Mass Transfer Models on Rate-Based Simulations of CO2 Absorption and Desorption Processes2017Inngår i: Energy Procedia, ISSN 1876-6102, E-ISSN 1876-6102, Vol. 142, s. 3747-3752Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    One of the keys available options for the large scale carbon capture and storage is the solvent-based post-combustion capture. Due to the high reactivity between CO2 and aqueous amine solutions, chemical absorption is suitable for capturing the CO2 at low concentration such as from the flue gas. From techno-economic analyses of the CO2 chemical absorption plant, absorber and desorber columns are the main cost of the purchased equipment. Since the process involves complex reactive separations, the accurate calculation of hydrodynamic properties, mass and energy transfer are of importance for the design of the columns. Several studies have been done on the impact of different process and property models on the equilibrium and rate-based simulation of the absorption site. However, the impact study of process and property models on the desorption site are still lacking. This paper performs rate-based simulations of CO2 absorption by Monoethanolamine. The software Aspen Plus was used for the simulations. Different mass transfer models were implemented for the mass transfer calculation in gas and liquid phases. The temperature and concentration profiles along the columns are reported and discussed.

  • 78.
    Nordlander, Eva
    et al.
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling. Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Eva, Thorin
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Yan, JinYue
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. KTH-Royal Institute of Technology, Stockholm, Sweden.
    Investigating the possibility of applying an ADM1 based model to a full-scale co-digestion plant2017Inngår i: Biochemical engineering journal, ISSN 1369-703X, E-ISSN 1873-295X, Vol. 120, s. 73-83Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This study investigated the possibility of using a model based on the anaerobic digestion model no. 1 (ADM1) on a full-scale 4000 m3 digester in order to understand how such theoretical models can be applied to a real industrial process. The industrial scale digester co-digests the organic fraction of municipal solid waste, grease trap sludge, and ley crop silage with varying feed rates and amounts of volatile solids. A year of process data was collected. Biogas flow, methane content/flow, and ammonia nitrogen were the variables that the model was best at predicting (index of agreement at 0.78, 0.61/0.77, and 0.68, respectively). The model was also used to investigate the effect of increasing the volatile solids (VS) concentration entering the digester. According to simulation results, increasing the influent VS concentration will increase biogas and methane outflow (from 1.5 million Nm3 methane to more than 2 million Nm3 methane), but decrease the amounts of biogas/methane per unit of volatile solids (from about 264 Nm3methane per tonne VS to below 215 Nm3 methane per tonne VS).

  • 79.
    Nordlander, Eva
    et al.
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling.
    Holgersson, Jenny
    Eskilstuna Energi och Miljö.
    Thorin, Eva
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling.
    Thomassen, Martin
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling.
    Yan, Jinyue
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling.
    Energy Efficiency Evaluation of two Biogas Plants2011Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Anaerobic digestion for biogas production is a promising renewable energy technology whichcan be used to achieve environmental goals set in the European Union and other regions. Thereare however many improvements that can still be made to the process. Furthermore, there arealternative energy conversion processes that compete for some of the substrates used inanaerobic digestion. Energy efficiency could therefore be a tool for measuring and comparingthe performance of biogas plants. This study suggests a method for calculating energyefficiency of the biogas plant so that it is comparable to other processes. Two examples ofexisting biogas plants in Sweden have been selected for the efficiency assessment by using themethod proposed in this paper. The results are compared between the plants to assess thefurther potential of improvement.

  • 80.
    Nordlander, Eva
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik.
    Thorin, Eva
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik.
    Yan, Jinyue
    KTH.
    Modeling of a full-scale biogas plant using a dynamic neural network2013Konferansepaper (Fagfellevurdert)
  • 81.
    Nordlander, Eva
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Olsson, Jesper
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Thorin, Eva
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Yan, Jinyue
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Simulation of energy balance and carbon dioxide emission for microalgae introduction in wastewater treatment plants2017Inngår i: Algal Research, ISSN 2211-9264, Vol. 24, nr part A, s. 251-260Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A case study is described in which the activated sludge process is replaced with a microalgae-activated sludge process. The effects on the heat and electricity consumption and carbon dioxide emissions were evaluated in a system model, based on mass and energy balances of biological treatment and sludge handling process steps. Data for use in the model was gathered from three wastewater treatment plants in Sweden. The evaluation showed that the introduction of microalgae could reduce electricity and heat consumption as well as CO2 emissions but would require large land areas. The study concludes that a 12-fold increase in the basin surface area would result in reductions of 26–35% in electricity consumption, 7–32% in heat consumption and 22–54% in carbon dioxide emissions. This process may be suitable for wastewater treatment plants in Nordic countries, where there is a higher organic load in summer than at other times of the year. During the summer period (May to August) electricity consumption was reduced by 50–68%, heat consumption was reduced by 13–63% and carbon dioxide emissions were reduced by 43–103%.

  • 82.
    Nyström, Jenny
    et al.
    Mälardalens högskola, Institutionen för samhällsteknik.
    Thorin, Eva
    RF-Measurements of Moisture Content of Biofuel using Time Domain SignalsManuskript (Annet vitenskapelig)
  • 83.
    Nyström, Jenny
    et al.
    Mälardalens högskola, Institutionen för samhällsteknik.
    Thorin, Eva
    Backa, Stefan
    Dahlquist, Erik
    Moisture Content Measurements on Sawdust with Radio Frequency Spectroscopy2005Inngår i: Proceedings of ASME Power, Chicago, Illinois, USA, April 5-7, 2005(2005), 2005Konferansepaper (Fagfellevurdert)
  • 84.
    Odlare, Monica
    et al.
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling.
    Abubaker, Jamal
    SLU.
    Lindmark, Johan
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling.
    Pell, Mikael
    SLU.
    Thorin, Eva
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling.
    Nehrenheim, Emma
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling.
    Emissions of N2O and CH4 from agricultural soils amended with two types of biogas residues2012Inngår i: Biomass and Bioenergy, ISSN 0961-9534, E-ISSN 1873-2909, Vol. 44, s. 112-116Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Biogas residues contain valuable plant nutrients, important to the crops and also to soil microorganisms. However, application of these materials to the soils may contribute to the emission of greenhouse gases (GHG) causing global warming and climate change. In the present study, incubation experiment was carried out, where the emission rates of N2O and CH4 were measured after amending two soils with two types of biogas residues: (1) a regular residue from a large scale biogas plant (BR) and (2) a residue from an ultrafiltration membrane unit connected to a pilot-scale biogas plant (BRMF). The emissions of N2O and CH4 were measured at two occasions: at 24 h and at 7 days after residue amendment, respectively. Amendment with filtered biogas residues (BRMF) led to an increase in N2O emissions with about 6-23 times in organic and clay soil, respectively, in comparison to unfiltered biogas residues (BR). Methane emission was detected in small amounts when filtered biogas residue was added to the soil. Amendment of unfiltered biogas to the organic soil resulted in net consumption. In conclusion, fertilization with BRMF can be combined with risk of an increase N2O emission, especially when applied to organic soils. However, in order to transfer these results to real life agriculture, large scale field studies need to be carried out

  • 85.
    Odlare, Monica
    et al.
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling.
    Nehrenheim, Emma
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling.
    Ribé, Veronica
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik.
    Thorin, Eva
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling.
    Grube, Mara
    Latvia University.
    Gavare, Marita
    Latvia University.
    Cultivation of algae with indigenous species – potentials for regional biodiesel, biogas and biofuel production.2010Konferansepaper (Fagfellevurdert)
  • 86.
    Odlare, Monica
    et al.
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling.
    Nehrenheim, Emma
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik.
    Ribé, Veronica
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik.
    Thorin, Eva
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling.
    Grube, Mara
    University of Latvia.
    Gavare, Marita
    University of Latvia.
    Cultivation of algae with indigenous species: potentials for regional biofuel production2011Inngår i: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 88, nr 10, s. 3280-3285Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The massive need for sustainable energy has led to an increased interest in new energy resources, such as production of algae, for use as biofuel. There are advantages to using algae, for example, land use is much less than in terrestrial biofuel production, and several algae species can double their mass in one day under optimized conditions. Most algae are phototrophs and some are nitrogen fixing. Algae production therefore requires only small amounts of amendments such as carbon sources and nutrients. In the present paper an experiment was performed using water sampled from Lake Mälaren in Sweden. The lake water is considered nutrient rich, has relatively neutral pH and is rich in organic compounds and suspended solids. The idea behind this research was to enhance indigenous algae production rather than inoculate new species into the system. A simple experimental setup was designed where algae biomass growth was measured regularly over a 13 day period. FT-IR absorption spectra were evaluated in order to determine protein, lipid, carbohydrate and silicate contents of the algae. The algae community structure was characterized throughout the production cycle. Futhermore, the potential for energy supply for the transportation sector in the Mälardalen region from algae cultivated as tested in the experiment was evaluated.

  • 87.
    Olsson, Jesper
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Feng, Xin Mei
    JTI, Swedish Inst Agr & Environm Engn, SE-75007 Uppsala, Sweden .
    Ascue, Johnny
    JTI, Swedish Inst Agr & Environm Engn, SE-75007 Uppsala, Sweden .
    Gentili, Francesco G.
    Swedish Univ Agr Sci, Dept Wildlife Fish & Environm Studies, SE-90183 Umea, Sweden .
    Shabiimam, M. A.
    Indian Inst Technol, Ctr Environm Sci & Engn, Bombay 400076, Maharashtra, India.
    Nehrenheim, Emma
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Thorin, Eva
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Co-digestion of cultivated microalgae and sewage sludge from municipal waste water treatment2014Inngår i: Bioresource Technology, ISSN 0960-8524, E-ISSN 1873-2976, Vol. 171, s. 203-210Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In this study two wet microalgae cultures and one dried microalgae culture were co-digested in different proportions with sewage sludge in mesophilic and thermophilic conditions. The aim was to evaluate if the co-digestion could lead to an increased efficiency of methane production compared to digestion of sewage sludge alone. The results showed that co-digestion with both wet and dried microalgae, in certain proportions, increased the biochemical methane potential (BMP) compared with digestion of sewage sludge alone in mesophilic conditions. The BMP was significantly higher than the calculated BMP in many of the mixtures. This synergetic effect was statistically significant in a mixture containing 63% (w/w VS based) undigested sewage sludge and 37% (w/w VS based) wet algae slurry, which produced 23% more methane than observed with undigested sewage sludge alone. The trend was that thermophilic co-digestion of microalgae and undigested sewage sludge did not give the same synergy.

  • 88.
    Olsson, Jesper
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Forkman, T.
    Swedish University of Agricultural Sciences, Sweden.
    Gentili, F.G.
    Swedish University of Agricultural Sciences, Sweden.
    Zambrano, Jesús
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Schwede, Sebastian
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Nehrenheim, Emma
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Thorin, Eva
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Anaerobic co-digestion of sludge and microalgae grown inmunicipal wastewater: A feasibility study2018Inngår i: Water Science and Technology, ISSN 0273-1223, E-ISSN 1996-9732, Vol. 77, nr 3, s. 682-694Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In this study a natural mix of microalgae grown in wastewater of municipal character was co-digested with sewage sludge in mesophilic conditions, in both batch and semi-continuous modes. The semicontinuous experiment was divided into two periods with OLR 1 (Organic Loading Rate) of 2.4 kg VS m3 d-1 and HRT1 (Hydraulic Retention Time) of 15 days, and OLR2 of 3.5 kg VS m3 d-1 and HRT2 of 10 days respectively. Results showed stable conditions during both periods. The methane yield was reduced when adding microalgae (from 200 ± 25 NmL CH4 g VSin-1 , to 168±22 NmL CH4 g VSin-1). VS reduction was also decreased by 51%. This low digestability was confirmed in the anaerobic batch test. However, adding microalgae improved the dewaterability of the digested sludge. The high heavy metals content in the microalgae resulted in a high heavy metals content in the digestate, making it more difficult to reuse the digestate as fertilizer on arable land. The heavy metals are thought to originate from the flue gas used as a CO2 source during the microalgae cultivation. Therefore the implementation of CO2 mitigation via algal cultivation requires careful consideration regarding thesource of the CO2-rich gas.

  • 89.
    Olsson, Jesper
    et al.
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling.
    Ma, Shabiimam
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling.
    Nehrenheim, Emma
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling.
    Thorin, Eva
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling.
    Co-digestion of cultivated microalgae and sewage sludge from municipal waste water treatmentManuskript (preprint) (Annet vitenskapelig)
    Abstract [en]

    One way to meet the increased demand for biogas in the society is to use microalgae as substrate. These algae would be cultivated in a treatment step of photobioreactors for reject water from sludge dewatering facilities. In the present study, a co-digestion experiment was established where sludge from a municipal wastewater treatment plant was fermented with harvested microalgae cultivated in lake water from lake Mälaren. The experiment was carried out as a BMP-test (Biochemical Methane Potential) under mesophilic condition (37°C) with fermentation bottles, where 0, 12, 25 and 37%, of the sludge was replaced with harvested microalgae. The results showed that the biogas production was improved with 12% for the bottles with 12% microalgae compared with the bottles with only sludge as a substrate. In the bottles with 25% and 37% microalgaes the gas production was slightly reduced compared with the bottles where only sludge was used.

  • 90.
    Olsson, Jesper
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Philipson, M.
    Uppsala University, Sweden.
    Holmström, H.
    Uppsala Vatten Och Avfall AB, Sweden.
    Cato, E.
    Uppsala Vatten och Avfall AB, Sweden.
    Nehrenheim, Emma
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Thorin, Eva
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Energy efficient combination of sewage sludge treatment and hygenization after mesophilic digestion - Pilot study2014Inngår i: Energy Procedia, ISSN 1876-6102, E-ISSN 1876-6102, Vol. 61, s. 587-590Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Biogas production is probably the most feasible way of utilizing sewage sludge as energy source, simultaneously with nutrient recovery by recycling the biogas digestate (i.e. The residue) to arable land. However, the sludge commonly contains high amounts of human pathogenic bacteria excreted in faeces and urine. To use sludge as fertilizer on food producing land is therefore a controversial issue, partly because of the risk of spreading diseasecausing pathogens. The Swedish environment protection agency (SEPA) pre-approved two hygenization methods for the treatment of the sludge due to their positive effects on the sludge quality. One of them, conventional pasteurization (70 °C, 1 h), was investigated for its feasibility in Uppsala, Sweden, and it was found that the heat consumption was very high. The other method has the advantage of potentially increase the produced biogas. This hygenization method has been investigated in the present study through a pilot experiment where thickened mesophilic digested sludge is digested once more at thermophilic conditions (55 °C). The aim of the study was to investigate the possibility to develop this self-sufficient (in heat and electricity) hygenization method. The results showed an increase in the gas production from 430 dm3/kg VSin to 610 dm3/kg VSin by adding the thermophilic step. This increase gave an energy balance with an excess of both heat and electricity. Sludge hygenization was sufficient with the method and another important result is the significant decrease digestate volume.

  • 91.
    Olsson, Jesper
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Schwede, Sebastian
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Nehrenheim, Emma
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Thorin, Eva
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Co-digestion of microalgae, grown on municipal wastewater, and primary sewage sludge–: Pilot study in thermophilic and mesophilic conditions2017Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The most common biological treatment in a municipal waste water today is the activated sludge process (ASP). A possible substitution of the ASP could be the utilization of microalgae for the reduction and/or transformation of nutrients. The produced algal biomass can be converted to biofuel by anaerobic digestion. In the present study, co-digestion of primary sludge and microalgae are studied in semi-continuous tests at mesophilic and thermophilic conditions. Two reactors fed by waste activated sludge and primary sludge are used as reference. The results show that thermophilic digestion of microalgae and primary sludge is less attractive since the methane yield is approximately the same as the mesophilic digestion. In mesophilic conditions the results are approximately the same in the two pilot reactors and also comparable with the mesophilic full-scale digesters in Västerås, Sweden.

  • 92.
    Olsson, Jesper
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Schwede, Sebastian
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Nehrenheim, Emma
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Thorin, Eva
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Mesophilic and thermophilic co-digestion of microalgal-based activated sludge and primary sludgeInngår i: Water Science and Technology, ISSN 0273-1223, E-ISSN 1996-9732Artikkel i tidsskrift (Fagfellevurdert)
  • 93.
    Olsson, Jesper
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Schwede, Sebastian
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Nehrenheim, Emma
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Thorin, Eva
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Microalgae as biological treatment for municipal wastewater - Effects on the sludge handling in a treatment plant2018Inngår i: Water Science and Technology, ISSN 0273-1223, E-ISSN 1996-9732, ISSN 0273-1223, Vol. 78, nr 3, s. 644-654Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A mix of microalgae and bacteria was cultivated on pre-sedimented municipal wastewater in a continuous operated microalgae-activated sludge process. The excess material from the process was co-digested with primary sludge in mesophilic and thermophilic conditions in semi-continuous mode (5 L digesters). Two reference digesters (5 L digesters) fed with waste-activated sludge (WAS) and primary sludge were operated in parallel. The methane yield was slightly reduced (≈10%) when the microalgal-bacterial substrate was used in place of the WAS in thermophilic conditions, but remained approximately similar in mesophilic conditions. The uptake of heavy metals was higher with the microalgal-bacterial substrate in comparison to the WAS, which resulted in higher levels of heavy metals in the digestates. The addition of microalgal-bacterial substrate enhanced the dewaterability in thermophilic conditions. Finally, excess heat can be recovered in both mesophilic and thermophilic conditions. 

  • 94.
    Olsson, Jesper
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Shabiimam, MA
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Nehrenheim, Emma
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling. Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Thorin, Eva
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    CO-DIGESTION OF CULTIVATED MICROALGAE AND SEWAGE SLUDGE FROM MUNICIPAL WASTE WATER TREATMENT2013Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The demand for biogas is continuously growing and the biogas substrate, such as food waste, may soon become limited and it is therefore important for biogas producers to expand the range of substrates. One way can be to use microalgae in co-digestion with sewage sludge.

    The present study explores the possibilities to use harvested microalgae from Lake Mälaren, as a co-substrate to sewage sludge in biogas production under mesophilic and thermophilic conditions. The aim is to investigate if co- digestion of microalgae and sewage sludge is more efficient for biogas production compared using the sludge alone. The study has been carried out as a BMP-experiment (Biochemical Methane Potential) in batch fermentation bottles. The substrate was undigested sludge where 0%, 12 %, 25 % and 37 % were replaced with the cultivated microalgae. The results showed that the use of an algae/bacteria community, cultivated in prior to digestion, can serve as a biomass substrate for biogas production together with municipal wastewater sludge. Co-digestion of microalgae and sewage sludge can be more efficient for biogas production compared to using the sludge alone under mesophilic conditions. It can also be concluded that thermophilic co-digestion between the microalgae and sludge give lower biochemical methane potential. 

  • 95.
    Olsson, Jesper
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Thorin, Eva
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Nehrenheim, Emma
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    TRANSITION OF MESOPHILIC TO THERMOPHILIC DIGESTION OF SEWAGE SLUDGE2016Inngår i: TRANSITION OF MESOPHILIC TO THERMOPHILIC DIGESTION OF SEWAGE SLUDGE, 2016Konferansepaper (Fagfellevurdert)
    Abstract [en]

    In this comparative study two types of temperature transition strategies from mesophilic to thermophilic conditions in anaerobic digestion was explored. Both strategies used a rapid increase from 37 to 55°C with a constant organic loading rate (2.4 kg VS m-3 d-1) and hydraulic retention time (14 d). The two digesters used the same mesophilic inoculoum but in the second digester a small share of thermophilic digeastate was also inoculated. A comparative dewaterability study between the fullscale mesophilic digestate and the thermophilic digestates were also performed as part of the study. The results showed a stabilization in both digesters within 14 days (1 Hydraulic retention time). The digester where a small share of thermophilic inoculum was introduced had a higher methane production compared to the control reactor where just mesophilic inoculum was used. The comparative dewaterability study showed a deterioration of the dewaterability in both digesters when thermophilic conditions was established.

  • 96.
    Olsson, Jesper
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Thorin, Eva
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Nehrenheim, Emma
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Juszkiewicz, Agnieszka
    Mälarenergi AB, Sweden.
    Schwede, Sebastian
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    COMPARATIVE STUDY – PHARMACEUTICAL RESIDUES IN WASTEWATER AND SLUDGE FROM A MICORALGAE PLANT AND AN ACTIVATED SLUDGE PROCESS2016Konferansepaper (Fagfellevurdert)
    Abstract [en]

    This study explores the possibility of using a microalgae based activated sludge – process (MAAS-process) to increase the reduction of pharmaceutical residues in outgoing wastewater, compared to a conventional wastewater treatment plant with activated sludge process. In an on-site study, residual sludge from four pilot scale digesters fed with primary sludge and waste activated sludge or microalgae were sampled and analysed for pharmaceutical residues. The aim of the study was to compare the reduction efficiencies of a microalgae based process with a conventional biological treatment and also to explore the reduction of the residues in the different process steps including the sewage sludge thickening before the anaerobic digestion, the digestion and the secondary treatment with the sludge dewatering process. The results show that the total reduction of pharmaceutical residues in the water phase appears to be significantly higher in the MAAS-process. The substance diclofenac was not degraded in any of the biological processes in the study. The reduction of pharmaceutical residues in digested sludge seems to be higher in mesophilic conditions compared with thermophilic conditions.

  • 97.
    Olsson, Jesper
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Tova, Forkman
    Uppsala Universitet, Sweden.
    Nehrenheim, Emma
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Schwede, Sebastian
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Thorin, Eva
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    CONTINUOUS CO-DIGESTION OF MICROALGAE AND REPRESENTATIVE MIX OF SEWAGE SLUDGE: -2014Konferansepaper (Fagfellevurdert)
    Abstract [en]

    A natural mix of microalgae grown on wastewater was co-digested with a representative mix of sewage sludge in a semicontinuous pilot digester system. The share of microalgae in the mix were 37 % calculated as VS-content. The organic loading rate was 2.4 kg VS (volatile solids) m-3d-1 and the hydraulic retention time was 15 d in a reference reactor, with just a representative mix of sewage sludge, and a digester where microalgae were added. The results from the three retention times showed that the addition of the microalgae enhanced the methane yield with 39 % for every gram reduced VS in the reactors. The specific methane yield for every gram added VS to the reactors were 9 % lower in the digester where microalgae had been added. Less sludge was degraded when microalgae were added, but more methane was produced for every gram VS reduced. CST-measurements indicated that the addition of microalgae enhance the dewaterability of the digested sludge.

  • 98.
    Paz, Ana
    et al.
    Mälardalens högskola, Institutionen för samhällsteknik.
    Nyström, Jenny
    Thorin, Eva
    2006 IEEE Instrumentation and Measurement Technology Conference Proceedings2006Inngår i: IEEE Instrumentation and Measurement Technology Conference Proceedings, 2006, s. 175-179Konferansepaper (Fagfellevurdert)
    Abstract [en]

    A method that permits the determination of moisture content in biofuel in a fast and representative way is under development. Vie method uses radio frequency waves within the range of 310 MHz to 800 MHz and measures the reflection coefficient in samples with volume of about 0.1 m(3). The influence of sample temperature in the measurements is shown in this study. Two biofuel types were used, with moisture content varying between 31% and 63% and temperature varying between 1 degrees C and 63 degrees C. The data was evaluated with multivariate data analysis. Results show that it is not possible to identify the sample temperature as a principal component in a principal component analysis and partial least squares regression shows no correlation between temperature and the radio frequency data. For the frequency interval and the temperature range studied, it was not possible to detect any influence of sample temperature on moisture content prediction with the radio frequency method.

  • 99.
    Paz, Ana
    et al.
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling.
    Starfelt, Fredrik
    Dahlquist, Erik
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling.
    Thorin, Eva
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling.
    Yan, Jinyue
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling.
    How to achieve a fossil fuel free Malardalen region2007Inngår i: Conference proceedings of 3rd IGEC-2007,, 2007Konferansepaper (Fagfellevurdert)
  • 100.
    Paz, Ana
    et al.
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling.
    Thorin, Eva
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling.
    Dahlquist, Erik
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling.
    A new method for bulk measurement of water content in woody biomass2008Inngår i: 3rd Conference on environmental compatible forest products, 2008Konferansepaper (Fagfellevurdert)
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