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  • 101.
    Granström, Karin
    Karlstad University, Faculty of Technology and Science, Department of Energy, Environmental and Building Technology.
    A Method to Measure Emissions from Dryers with Diffuse Leakages2003Conference paper (Other (popular science, discussion, etc.))
    Abstract [en]

    The timber kiln drying process emits volatile organic compounds (VOC), which have long been recognised as one of the major air pollutants.



    This poster describes a novel method to measure emission from dryers and presents some results achieved.



    The method resolves the known difficulties caused by diffuse emissions, and also solves the problems associated with high moisture content of the drying medium (i.e. interference with VOC measuring equipment). The basic idea is to use the emitted water vapour to determine the volume of exhaust flow, while a dry ice trap is used both to preconcentrate emitted VOCs and to determine the moisture content of the drying medium.



    The feasibility and some advantages of this method was demonstrated measuring VOC emissions to air from a dryer with recirculating drying medium and in steady-state operation.



    The method was validated in two ways: using the controlled addition method and by comparison with Soxhlet extraction. The additions was detected to over 90%. The cold trap method detected a substance (p-cymene) that was not detected by Soxhlet extraction.

  • 102.
    Granström, Karin
    Karlstad University, Faculty of Technology and Science, Department of Energy, Environmental and Building Technology.
    A method to measure emissions from dryers with diffuse leakages II. Sensitivity studies2005In: Drying Technology 3(5):1127-1140, 2005Article in journal (Refereed)
    Abstract [en]

    Measurements of VOC emissions from dryers have several known difficulties. An earlier published method to measure emissions of VOC from dryers deals with problems associated with diffuse emissions and high moisture content of the drying medium([1]) In this article, a different calculation path are used and the influence of the main parameters are studied in more depth. For one experiment, confidence intervals for all of the parameters are calculated. Experimentally induced uncertainties are found to be more important than a theoretically important parameter. Suggestions are made on how to increase accuracy.

  • 103.
    Granström, Karin
    Karlstad University, Faculty of Technology and Science, Department of Energy, Environmental and Building Technology.
    A method to measure emissions from dryers with diffuse leakages, using evaporated water as a tracer2003In: Drying Technology 21(7):1197-1214, 2003Article in journal (Refereed)
    Abstract [en]

    This paper describes a novel method to measure emission from

    dryers. The method resolves the known diffculties caused by diffuse emissions,and also solves the problems associated with high moisture content of the drying medium. The basic idea is to use water vapor to determine the exhaust flow, while a dry ice trap is used both to preconcentrate emitted VOCs and to determine the moisture content of the drying medium.

  • 104.
    Granström, Karin
    Karlstad University, Division for Engineering Sciences, Physics and Mathematics.
    Biogenic emissions of monoterpenes in Sweden: a review with implications for modellingManuscript (Other (popular science, discussion, etc.))
  • 105.
    Granström, Karin
    Karlstad University, Faculty of Technology and Science, Department of Energy, Environmental and Building Technology.
    Effect of sawdust age on the storage quality of wood pellets2010Conference paper (Refereed)
  • 106.
    Granström, Karin
    Karlstad University, Faculty of Technology and Science, Department of Energy, Environmental and Building Technology.
    Emissions of hexanal and terpenes during storage of solid wood fuels2010In: Forest products journal, ISSN 0015-7473, Vol. 60, no 1, p. 27-32Article in journal (Refereed)
  • 107.
    Granström, Karin
    Karlstad University, Faculty of Technology and Science, Department of Energy, Environmental and Building Technology.
    Emissions of hexanal and terpenes during storage of wood sawdust and pellets2009Conference paper (Other (popular science, discussion, etc.))
  • 108.
    Granström, Karin
    Karlstad University, Faculty of Technology and Science, Department of Energy, Environmental and Building Technology.
    Emissions of monoterpenes and VOC during drying of sawdust in a continuous spouted bed2003In: Forest Products Journal 53(10):48-55,2003Article in journal (Refereed)
    Abstract [en]

    Emissions of volatile hydrocarbons are considered an environmental problem and a health problem. A wood-drying process is a source of volatile organic compound (VOC) emissions. Emissions of monoterpenes, as well as total VOCs, from a pilot-scale

    continuous spouted bed dryer have been investigated regarding the influence of the drying medium temperature and the final sawdust moisture content. The emissions from sawdust of Norway spruce (Picea abies), dried at three temperature schedules (140, 170 and 200°C), was analyzed by a gas chromatograph with a mass

    spectrometric detector and with a flame ionization detector. Emissions of terpenes and VOC per ovendry weight increased rapidly when the sawdust moisture content was reduced below 12 percent (wb).The concentration of VOCs in the drying medium, and the

    amount of emitted monoterpenes, increased with drying medium temperature. The composition of different monoterpenes in the drying medium was not influenced by the sawdust s final moisture content. The relative amount of less volatile monoterpenes increased with drying medium temperature

  • 109.
    Granström, Karin
    Karlstad University, Faculty of Technology and Science, Department of Energy, Environmental and Building Technology.
    Emissions of Monoterpenes and VOC during Drying of Sawdust in a Continuous spouted bed2002Conference paper (Refereed)
  • 110.
    Granström, Karin
    Karlstad University, Faculty of Technology and Science, Department of Energy, Environmental and Building Technology.
    Emissions of sesquiterpenes from spruce sawdust during drying2006Conference paper (Other (popular science, discussion, etc.))
  • 111.
    Granström, Karin
    Karlstad University, Faculty of Technology and Science, Department of Energy, Environmental and Building Technology.
    Emissions of sesquiterpenes from spruce sawdust during drying2009In: European Journal of Wood and Wood Products, ISSN 0018-3768, E-ISSN 1436-736X, Vol. 67, no 3, p. 343-350Article in journal (Refereed)
  • 112.
    Granström, Karin
    Karlstad University, Faculty of Technology and Science, Department of Energy, Environmental and Building Technology.
    Emissions of volatile organic compounds during drying of wood2002Licentiate thesis, monograph (Other academic)
  • 113.
    Granström, Karin
    Karlstad University, Faculty of Technology and Science, Department of Energy, Environmental and Building Technology.
    Emissions of volatile organic compounds from wood2005Doctoral thesis, monograph (Other academic)
    Abstract [en]

    The central aim of this thesis is to support the efforts to counteract certain environmental problems caused by emissions of volatile organic compounds.



    The purpose of this work was (1) to develop a method to establish the amount of emitted substances from dryers, (2) to determine the effect of drying medium temperature and end moisture content of the processed material on emissions of monoterpenes and other hydrocarbons, (3) to examine the emissions of monoterpenes during production of pellets, and (4) to examine the natural emissions from forests with an eye to implications for modelling.



    The measurement method (1) resolves the difficulties caused by diffuse emissions, and also solves the problems associated with high moisture content of the drying medium. The basic idea is to use water vapour to determine the exhaust flow, and to use a dry ice trap both to preconcentrate emitted VOCs and to determine the moisture content of the drying medium. The method, as used in this paper, has an uncertainty of 13% using a 95% confidence interval.



    Emissions from a spouted bed (2) in continuous operation drying Norway Spruce sawdust at temperatures of 140°C, 170°C or 200°C were analysed with FID and GC-MS. When the sawdust end moisture content was reduced below 10%wb, emissions of terpenes and of total VOC per oven dry weight increased rapidly. The increased temperature of the drying medium entering the drying tower also caused an increase in the amounts of emitted monoterpenes at sawdust moisture contents below the fibre saturation point.



    Examination of sawdust and wood pellets from different pellets producers (3) revealed that most of the terpene emissions take place during the drying step, with flue gas dryers causing higher emissions than steam dryers. Almost all of the volatile terpenes remaining in wood after drying were released during pelleting. Increased terpene emissions during the pelleting process were found when sawdust with a higher moisture content was used.



    Terpenes emitted naturally from vegetation can have adverse environmental impacts. Factors affecting terpene emissions from tree species in Sweden were reviewed (4). Models for prediction of terpene fluxes should include not only temperature but also light intensity, seasonal variation, and a base level of herbivory and insect predation. Prediction of high concentrations of ambient terpenes demand sufficient resolution to capture emission peaks, e.g., those caused by bud break.

  • 114.
    Granström, Karin
    Karlstad University, Division for Engineering Sciences, Physics and Mathematics.
    Emissions of volatile organic compounds from wood2005Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The central aim of this thesis is to support the efforts to counteract certain environmental problems caused by emissions of volatile organic compounds.

    The purpose of this work was (1) to develop a method to establish the amount of emitted substances from dryers, (2) to determine the effect of drying medium temperature and end moisture content of the processed material on emissions of monoterpenes and other hydrocarbons, (3) to examine the emissions of monoterpenes during production of pellets, and (4) to examine the natural emissions from forests with an eye to implications for modelling.

    The measurement method (1) resolves the difficulties caused by diffuse emissions, and also solves the problems associated with high moisture content of the drying medium. The basic idea is to use water vapour to determine the exhaust flow, while a dry ice trap is used both to preconcentrate emitted volatile organic compounds and to determine the moisture content of the drying medium. The method as used in this paper has an uncertainty of 13% using a 95% confidence interval.

    Emissions from a spouted bed (2) in continuous operation drying Norway spruce sawdust at temperatures of 140°C, 170°C or 200°C was analysed with FID and GC-MS. When the sawdust end moisture content was reduced below 10%wb, emissions of terpenes and volatile organic compounds per oven dry weight increased rapidly. Increased temperature of the drying medium increased the amounts of emitted monoterpenes when sawdust moisture content was below the fibre saturation point.

    Examination of sawdust and wood pellets from different pellets producers (3) revealed that most of the terpene emissions happened during the drying step, with rotary dryers causing higher emissions than steam dryers. Almost all of the volatile terpenes remaining in wood after drying were released during pelleting. When sawdust with higher moisture content was used in the pellets press, the terpene emissions were increased.

    Terpenes emitted naturally from vegetation can have an adverse environmental impact. Factors affecting terpene emissions from tree species in Sweden were reviewed (4). Models for prediction of terpene fluxes should include not only temperature but also light intensity, seasonal variation, and a base level of herbivory and insect predation. Prediction of high concentrations of ambient terpenes demand sufficient resolution to capture emission peaks e.g. those caused by bud break.

  • 115.
    Granström, Karin
    Karlstad University, Faculty of Technology and Science, Department of Energy, Environmental and Building Technology.
    Impregnerad träkubb som bränsle2005Report (Other academic)
    Abstract [sv]

    Träkubb med fuktkvot på knappt 6% impregnerades med en olja med effektivt värmevärde på 10,3 kWh/kg. Kubb som nedsänkts i olja under 6 till 127 timmar fick oljehalter räknat på torrsubstans på 75 till 105% för tall och 90 till 115% för gran. Vid förvaring i 50°C läckte olja från kubb med oljehalt över 110% för gran och 100% för tall. Kubb som sprayats med vatten till 20% fukthalt och med olja till 5 kWh/kg gav inga problem med läckage. Förbränning av sådan kubb gav emissioner av NO, NOx, SO2 och CO av samma storleksordning som vid eldning med pellets. Det var nödvändigt att göra smärre justeringar av pelletsbrännarens glödstift för att tändningen skulle fungera. Inmatning med matarskruv fungerade dåligt med kubbens nuvarande form. Frysning av kubben verkade inte påverka dess tändningsegenskaper negativt

  • 116.
    Granström, Karin
    Karlstad University, Faculty of Technology and Science, Department of Energy, Environmental and Building Technology.
    Kolväten från träbränsleindustrin: sågverk, trätorkar och pelletspressar: Handbok för myndigheter och industri2008Book (Refereed)
    Abstract [sv]

    Detta faktablad innehåller snabb och lättillgänglig information om kolväteutsläpp från produktionen av träbaserade fasta biobränslen, specifikt från sågning, trätorkning och pelletspressning. Faktabladet är tänkt som ett hjälpmedel för länsstyrelser och kommuner vid handläggning av tillsyns- och prövningsärenden. Skriften ska också vara ett stöd för verksamhetsutövare.

    Frågor som behandlas är (1) typiska utsläppsnivåer för kolväten från sågverk, torkar och pelleteringsanläggningar, (2) klargörande av hur olika produktionsmetoder och råvaror skiljer sig åt med avseende på mängden kolväten som avgår, (3) en uppskattning av betydelsen av antropogena utsläpp jämfört med de naturliga emissionerna av terpener från barrskog, och (4) förslag på hur kolväteutsläpp från träbränsleindustrin kan minskas vid behov.

  • 117.
    Granström, Karin
    Karlstad University, Faculty of Technology and Science, Department of Energy, Environmental and Building Technology.
    Ny ångtorkningsteknik i mellanstor skala2003Conference paper (Other (popular science, discussion, etc.))
  • 118.
    Granström, Karin
    Karlstad University, Faculty of Technology and Science, Department of Energy, Environmental and Building Technology.
    On the environmental aspects of pellets production2011Conference paper (Refereed)
  • 119.
    Granström, Karin
    Karlstad University, Faculty of Technology and Science, Department of Energy, Environmental and Building Technology.
    Reduced VOC Emissions from Birch Sawdust Dried in a Steam Dryer2003Conference paper (Other (popular science, discussion, etc.))
    Abstract [en]

    Large amounts of sawdust are dried for production of particleboard and pellets. During drying of wood, volatile organic compounds (VOC) are emitted. VOC emissions contribute in the presence of nitrogen oxides and sunlight to the formation of ground level ozone and other harmful photo-oxidants.



    While several studies have been made on the amount and composition of emissions from softwoods during drying, hardwoods have been given less attention. Hardwoods have different wood structure and also differ in the chemical composition of volatiles.



    In this study emissions of VOC from birch sawdust during drying in a steam dryer at atmospheric pressure were investigated. The drier was a pilot scale continuous spouted bed. Both the amount and the composition of emissions were determined. The sawdust was dried to different moisture contents in two drying medium temperatures (170 °C and 200 °C).



    The results are compared to the emissions from softwoods dried in similar conditions. The results of this study should help to reduce emissions of volatile hydrocarbons during drying of hardwood sawdust and wood chips.

  • 120.
    Granström, Karin
    Karlstad University, Faculty of Technology and Science, Department of Energy, Environmental and Building Technology.
    Some reflections on the modelling of biogenic emissions of monoterpenes in the boreal zone2008In: / [ed] Edited by C.A. Brebbia, J.W.S. Longhurst, UK: Wessex Institute of Technology , 2008Conference paper (Refereed)
    Abstract [en]

    Trees emit volatile organic compounds, mostly monoterpenes and isoprene. These biogenic substances are the dominant volatile organic compounds in air in forested regions. They contribute to the formation of tropospheric ozone and other photochemical oxidants if mixed with polluted air from urban areas. Increased ozone levels hamper photosynthesis and thus have a negative impact on the growth of forests and crops. Terpene flux estimations are needed for models of atmospheric chemistry and for carbon budgets. Several models of natural terpene emission have been constructed, both in a global scale and for various regions. Ideally, a model of natural terpene emissions should show the terpene flux at different times of day and year, at different weather conditions, and for different ecosystems. Its resolution should be sufficient to show short emission peaks. It should also be able to accommodate extreme events like pest outbreaks and serious storms, especially since those are expected to become more common due to global warming. An examination of the scientific literature on monoterpene content in trees and emission fluxes for the dominant boreal forest tree species shows that models aiming to predict terpene fluxes from natural sources over time should include the factors temperature and light intensity, and possibly also take into account the seasonal variation of terpene levels in trees. As wood tissue damage increases emissions, a base level of herbivory and insect predation should be estimated and included. When identification of high concentrations is important, models should have sufficient resolution to capture the emission peaks found, for example, at bud break. The temperature dependence is shown to vary sufficiently between different tree species to motivate using specific values for the ecosystems examined.

  • 121.
    Granström, Karin
    Karlstad University, Faculty of Technology and Science, Department of Energy, Environmental and Building Technology.
    Underestimation of terpene exposure in the Nordic wood industry2009In: Journal of Occupational and Environmental Hygiene, ISSN 1545-9624, E-ISSN 1545-9632, Vol. 7, no 3, p. 144-151Article in journal (Refereed)
  • 122.
    Granström, Karin
    Karlstad University, Faculty of Technology and Science, Department of Energy, Environmental and Building Technology.
    Utsläpp av lättflyktiga kolväten vid torkning av biobränslen: Värmeforskrapport 7452001Report (Refereed)
    Abstract [sv]

    Projektet omfattar en undersökning av vilka ämnen som avgår vid torkning av gran- och furuspån, samt data över energieffektivitet, vid olika torkbetingelser. Målet är att minimera både emissioner och energibehov, i syfte att minska miljö- och hälsoeffekter av torkning, samt öka det ekonomiska utbytet av torkningen. Därmed kan den primära målgruppen sågverk få bättre möjligheter att producera pellets och briketter.



    Genomförande: Torkningen har skett under atmosfärstryck i en fluidiserad tork i pilotskala, med recirkulerande eller icke-recirkulerande torkmedium. Emissionerna av kolväten har mätts med flamjonisations-detektor (FID). En analys av vilka kolväten som ingår i emissionerna har gjorts med en gaskromatograf med masspektrometer (GC/MS).



    Resultaten från GC/MS redovisas som vikt monoterpener per vikt torrsubstans sågspån. Undersökningar av terpenavgång vid torkning med recirkulerande torkgas visar att långt driven torkning medför större terpenavgång. Så länge spånen inte torkas till fukthalter (vatten/totalvikt) under ca 10% är mängden terpener som avgår liten, men om spånen torkas till lägre fukthalter så ökar terpenavgången snabbt. Mängden avgivna terpener ökar med temperaturen på torkgasen in till torktornet för bestämd fukthalt på utgående spån. De dominerande monoterpenerna är a-pinen, b-pinen och 3-karen. Därnäst kommer myrcen och limonen. Fördelningen mellan olika monoterpener i emissionerna kan skilja sig för spån som sågats olika dagar. y-terpinen har hittats vid torkning av furuspån men inte i granspån. Det inbördes mängdförhållandet av olika monoterpener i torkgasen verkar inte påverkas av hur långt torkningen av spånen drivs. En ökad temperatur på torkgasen in till torktornet påverkar fördel-nin-gen av terpener i torkgasen på så sätt att andelen av myrcen och limonen (de högkokande mono-terpenerna) ökar relativt de andra monoterpenerna.



    Flamjonisationsdetektorns resultat redovisas som koncentration av kolväten i torkgasen och som vikt kolväten per vikt torrsubstans sågspån. Mätningar med FID visar att koncentrationen av kolväten då torkgasen recirkuleras når stationärt tillstånd och att kolvätekoncentrationen vid bestämd spånslutfukthalt ökar med temperaturen på torkgas in till torktornet. En massbalans för recirkulerande torkgas visar att kolvätekoncentrationen i torkgasen vid bestämd fukthalt på in- och utgående spån är proportionell mot kolväteavgången per torrsubstans, medan torkgasflödet och spånflödet inte påverkar kolvätekoncentrationen. Undersökningar av kolväteavgången per torrsubstans visar att den ökar med minskad slutfukthalt och ökande temperatur på torkgas in till torktornet.



    Energieffektiviteten förbättras då temperaturen på torkgas in till torktornet ökar, men försämras då spånets fukthalt sjunker oavsett temperatur på torkgas in till torktornet. Energieffektiviteten var högre då torken kördes med återcirkulering av torkgasen.



    En viktig slutsats är att fluidiserad tork ska använda recirkulering av torkmediet. En annan viktig slutsats är att för att minimera emissionerna vid torken bör temperaturen på torkgas in till torktornet hållas låg och utgående spånfukthalt vara mer än ca 10%.



    Nyckelord: VOC, terpener, fluidiserad bädd, torkning, energieffektivitet

  • 123.
    Granström, Karin
    Karlstad University, Faculty of Technology and Science, Department of Energy, Environmental and Building Technology.
    Utvärdering av miljöanpassat reningsverk i Hammarö kommun ur ett kretsloppsperspektiv - minskning av transportarbete och näringsläckage2007Report (Refereed)
    Abstract [sv]

    Hammarö kommuns reningsverk vid Sätter har biologisk rening av kväve och fosfor. Det byggdes för att få bort ineffektiva enskilda avlopp och istället skapa ett ekologiskt hållbart kretslopp för lokalt återbruk av avlopp och organiskt hushållsavfall. Ledningsnätet är ännu inte fullt utbyggt. Här analyseras vinsterna med de olika faserna i en kommande utbyggnad av ledningsnätet. Att hushållsavfallets organiska del transporteras i avloppsledningarna har hittills inte påverkat soprutter eller hämtningsfrekvens, så transportarbetet för sopor är oförändrat. Genomslaget för avfallskvarnar är när denna studie görs 35%, vilket inte är tillräckligt för att märkbart påverka sopmängderna. En större acceptans för avfallskvarnar

    behövs. Om nuvarande genomslag i befintlig bebyggelse kvarstår, men avfallskvarn blir obligatoriskt i nybyggda områden, så minskar mängden näringsämnen i de sopor som går till förbränning med 54%. Transportarbetet för slam från östra Hammarö var före byggandet av Sätterverket 12600 km/år. Det minskar till 5500 km/år efter utbyggnaden av ledningsnät till Rud och Torp, till 3000 km/år när ledningsnät dragits till östraste Hammarö, för att helt upphöra när Tynäs kopplas på. I södra Hammarö behålls enskilda avlopp, men transportavståndet för producerat slam blir kortare. Transporterna minskar därför från 4500 km/år till 4200 km/år, vilket motsvarar 170 liter drivmedel. Ett fullt utbyggt ledningsnät på östra Hammarö reducerar transporterna med 60%, vilket motsvarar en

    drivmedelsförbrukning på 6900 liter/år. När anslutningen av Rud och Torp är genomförd minskar läckaget av kväve med 1080 kg och av fosfor med 190 kg. Inkoppling av östraste Hammarö minskar näringsämnesläckaget med 480 kg kväve och 85 kg fosfor. När Tynäs ansluts minskas läckaget med ytterligare 542 kg kväve och 95 kg fosfor

  • 124.
    Granström, Karin
    Karlstad University, Faculty of Technology and Science, Department of Energy, Environmental and Building Technology.
    Utvärdering av miljöanpassat reningsverk i Hammarö kommun ur ett kretsloppsperspektiv förstudie för etablering av nollpunkt2005Report (Refereed)
    Abstract [sv]

    Hammarö kommun bygger ett nytt reningsverk för avloppsvatten och organiskt hushållsavfall. Reningsverket består av en förbehandling, ett aktivt slamsteg samt en efterföljande våtmark. Slammet hygieniseras i en våtkompost och avvattnas i en vassbädd. Avrinningen ska vara fosforrik och användas för kombinerad gödsling och bevattning. Avvattnat slam ska användas som jordförbättringsmedel. Syftet med reningsverket är att få till ett lokalt kretslopp av organiskt hushållsavfall, och minskade avfallstransporter.

    Hammarö kommun ligger i Värmland vid Klarälvens mynning i Vänern. Utanför centralorten finns spridd permanent bebyggelse och omfattande fritidsbebyggelse utan anslutning till kommunalt vatten och avlopp. Marken karakteriseras av berg i dagen, tunn jordmån, och lera

    eller tät morän. Infiltration som reningsmetod har därmed dåliga förutsättningar. Med nuvarande enskilda avloppslösningar föreligger stora risker för läckage av näringsämnen till Vänern. Dåligt renat avloppsvatten utgör också en risk för vattenkvaliteten i enskilda

    brunnar. Syftet med rapporten är att före byggandet av Hammarös nya reningsverk klargöra storleken på flöden av näringsämnen och mängden transporter av hushållsavfall i området. Detta för att etablera den nollpunkt som behövs för att senare kunna bedöma vilka

    förbättringar som uppnåtts med det nya reningskonceptet. Från hushåll på östra Hammarö går

    930 kg kväve och 120 kg fosfor till det nuvarande reningsverket på Vidön, medan 2100 kg kväve och 370 kg fosfor läcker ut till omgivningen. Transportarbetet på Hammarö för sopor, latrin, slam och tankinnehåll är ca 21000 km per år. Detta fördelar sig på sopor 3900 km/år, latrin 480 km/år, slam 5700 km/år och tankinnehåll 11000 km/år

  • 125.
    Granström, Karin
    Karlstad University, Faculty of Technology and Science.
    Utvärdering av miljöanpassat reningsverk i Hammarö kommun ur ett kretsloppsperspektiv: förstudie för etablering av nollpunkt2005Report (Other (popular science, discussion, etc.))
    Abstract [en]

    The Hammarö municipality in the region Värmland is building a wastewater plant for both wastewater and organic household waste.  The aim is to create an ecologically sustainable system for the local recycling of wastewater and organic household waste.  The plant is based on biological purifying processes, and outflows are treated in a constructed wetland.  The sludge is treated in a wet compost and in a bed of reeds.  Phosphorous will be collected and used for fertilizer.  The net result is expected to be a decreased nutrient load to the recipient.  Hammarö have a major town (of 12 000 people) with central water and wastewater facilities.  The new plant is to serve scattered villages and cottage summer houses.  The performance of existing private wastewater treatments is in many cases unsatisfactory, and with the ground at Hammarö characterized by cliffs, thin layers of dirt, and moraine, the prospects for wastewater purification through infiltration is not good.  The aim of this report is to calculate the current situation regarding the flows of nutrients from private wastewater treatments, and the transport work of organic garbage and waste.  This to establish a baseline from which to judge the size of coming improvements.  From households in the eastern part of Hammarö, where households are to be connected to the new wastewater plant, leaks 2100 kg nitrogen and 370 kg phosphorous to the environment, whereas 930 kg nitrogen and 120 kg phosphorous is transported to the municipality's existing wastewater facility.  Transports amounts to 21000 km annually, distributed as 3900 km/year for organic garbage, 480 km/year for latrine, 5700 km/year for sludge and 11000 km/year for closed tanks.

     

  • 126.
    Granström, Karin
    Karlstad University, Faculty of Technology and Science.
    Utvärdering av miljöanpassat reningsverk i Hammarö kommun ur ett kretsloppsperspektiv: minskning av transportarbete och näringsläckage2007Report (Other (popular science, discussion, etc.))
    Abstract [en]

    Hammarö municipality has a new wastewater treatment plant with biological purifying processes. It processes both wastewater and organic household waste. The aim of this report is to calculate the impacts on transports and nutrient leakage of connecting different villages to this plant. The use of garbage mills to transport organic household waste in sewers has not yet caused a noticeable decrease in the amount of household garbage collected, as only 35% of the households have installed a mill. If this percentage persists in existing houses, but mills are made mandatory in planned new villages, the nutrients lost through incarnation of household waste will decrease with 54%. Before the new plant was in operation, sludge was transported by vehicles. The transport load was 12600 km/year. This will decrease to 5500 km/year when the villages Rud and Torp are connected to the plant, to 3000 km/year when the easternmost parts of Hammarö are connected, and cease completely when the village Tynäs is connected. A fully constructed sewerage system on eastern Hammarö will cause a reduction in transports by 60%, which will save almost 7000 liters of fuel a year. When households in Rud and Torp are connected to a wastewater purification plant, their previous leakage of 1080 kg nitrogen and 190 kg phosphorous will cease. Connection of the easternmost parts of Hammarö will remove leakage of 480 kg nitrogen and 85 kg phosphorous, and connection of Tynäs will remove an additional 542 kg nitrogen and 95 kg phosphorous.

  • 127.
    Granström, Karin
    Karlstad University, Faculty of Technology and Science, Department of Energy, Environmental and Building Technology.
    Wood processing as a source of terpene emissions compared to natural sources2007In: / [ed] C.A. BREBBIA, UK: WIT Press , 2007Conference paper (Refereed)
  • 128.
    Granström, Karin
    et al.
    Karlstad University, Faculty of Technology and Science, Department of Energy, Environmental and Building Technology.
    Berghel, Jonas
    Karlstad University, Faculty of Technology and Science, Department of Energy, Environmental and Building Technology.
    Renström, Roger
    Karlstad University, Faculty of Technology and Science, Department of Energy, Environmental and Building Technology.
    Ståhl, Magnus
    Karlstad University, Faculty of Technology and Science, Department of Energy, Environmental and Building Technology.
    Steam Drying of Sawdust for Pellets Production2003Conference paper (Other (popular science, discussion, etc.))
  • 129.
    Granström, Karin
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
    Hagelqvist, Alina
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
    Sandberg, Maria
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
    Efficiency of techniques for purification of condensate from wood dryers2013Conference paper (Refereed)
  • 130.
    Granström, Karin
    et al.
    Karlstad University, Faculty of Technology and Science, Department of Energy, Environmental and Building Technology.
    Javeed, Asif
    Emissions from bed drying of sawdust for pellets production2013Conference paper (Refereed)
  • 131.
    Granström, Karin
    et al.
    Karlstad University, Faculty of Technology and Science, Department of Energy, Environmental and Building Technology.
    Månsson, Bengt
    Karlstad University, Faculty of Technology and Science, Department of Energy, Environmental and Building Technology.
    Thermic degradation of hardwood during drying as a function of processing parameters2008Conference paper (Other (popular science, discussion, etc.))
  • 132.
    Granström, Karin
    et al.
    Karlstad University, Faculty of Technology and Science, Department of Energy, Environmental and Building Technology.
    Månsson, Bengt
    Karlstad University, Faculty of Technology and Science, Department of Energy, Environmental and Building Technology.
    Volatile organic compounds emitted from hardwood drying as a function of processing parameters2008In: International Journal of Environmental Science and Technology, ISSN 1735-1472, E-ISSN 1735-2630, Vol. 5, no 2, p. 141-148Article in journal (Refereed)
    Abstract [en]

    During the drying of wood, volatile organic compounds are emitted. These emissions contribute, in the presence of nitrogen oxides and sunlight, to the formation of ground level ozone and other harmful photo-oxidants. Emissions of volatile organic compounds from the drying of birch sawdust in a spouted bed were analyzed with a flame ionization detector by flame ionization detector and with a gas chromatograph-mass pectrometer GC MS. A D-optimal model of the volatile organic compounds emissions showed that the emissions increased exponentially with decreasing sawdust moisture content and that the final sawdust moisture content was influencinge emissions about twice as much as the inlet drying medium temperature and the month of logging. At inlet temperatures of 140-170 °C, the emissions increased steeply when the moisture content of the sawdust reached 10 %, whereas an inlet temperature of 200 °C caused a surge of thermal degradation products at 15 % moisture content. The results of this study should help to reduce the emissions of volatile hydrocarbons during the drying of hardwood sawdust and wood chips

  • 133.
    Granström, Karin
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences (from 2013). Karlstad Univ, Dept Engn & Chem Sci, SE-65188 Karlstad, Sweden..
    Sandberg, Maria
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences (from 2013). Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Environmental and Life Sciences (from 2013). Karlstad Univ, Dept Engn & Chem Sci, SE-65188 Karlstad, Sweden..
    Characterization of Wood-Dryer Condensate with Assessment of Toxicity to Microorganisms2017In: Journal of environmental engineering, ISSN 0733-9372, E-ISSN 1943-7870, Vol. 143, no 7, article id 04017019Article in journal (Refereed)
    Abstract [en]

    Drying of wood causes airborne emissions that can be reduced by recirculating all or part of the drying medium. This favors both emission control and energy efficiency, but results in a condensate that contains significant amounts of organic compounds. Drying operations have been requested by municipal regulatory bodies to clean the condensate before release. The industry has tested biological treatment of condensate from biomass dryers, but maintaining the viability of microorganisms has been a challenge. In this study, the effect of drying gas temperature and the final wood moisture content on the chemical composition and acute toxicity of the condensate was tested. Results showed that whereas the condensate from wood drying was extremely toxic to Vibrio fischeri employed in Microtox assays, the undefined mixed culture present in biosludge from a pulp and paper mill treatment plant were considerably less affected. (C) 2017 American Society of Civil Engineers.

  • 134. Greeff, Oliver
    et al.
    Nørh Glud, Ronnie
    Gundersen, Jens
    Holby, Ola
    Karlstad University, Faculty of Technology and Science, Department of Energy, Environmental and Building Technology.
    Barker Jørgensen, Bo
    A benthic lander for tracer studies in the sea bed: in situ measurements of sulfate reduction1998In: Continental shelf research. 18:1581-1594Article in journal (Refereed)
  • 135.
    Green, Gustav
    Karlstad University.
    Systemanalys av termisk samverkan mellan solceller och värmepump i flerbostadshus: Modellering och scenarioanalyser av innovativa systemutformningar samt  väderförhållanden med fokus på energi, klimat och ekonomi2018Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    It is discussed in today’s society to reduce the carbon dioxide emissions by replacing old, fossil fueled, electricity production with new, renewable and “green” ways of producing electricity. Photovoltaics have lately become cheaper which can be seen by looking at the increase in installed electric power from apartment buildings for each year in Sweden. This is mainly caused by the introduction of subsidies towards photovoltaics in 2006 from the Swedish state. The efficiency of photovoltaics increases when the solar radiation is higher but decreases with increasing cell temperature of the photovoltaic cells. The COP of heat pumps, which is commonly used for heating apartment buildings, is increased with increased brine temperature which increases the potential of heating. This means that photovoltaics can benefit from a cold brine while heat pumps can benefit from a higher brine temperature by heat exchanging with photovoltaics. Thermal cooperation is possible. The purpose of the study is to do a system analysis of how photovoltaics and heat pump can cooperate in an energy and cost-efficient energy system through thermal cooperation.

    Two models, of an energy system in an apartment building located in Karlstad, have been built in this study; with and without thermal cooperation between heat pump and photovoltaics. The energy system is divided in two subsystems; heating and electricity system. The heating system consists of an exhaust air heat pump with district heating during peaks and the electricity system consists of the electricity demand from the apartment building and photovoltaics. The results of the models are compared with focus on purchase of electricity and district heating, selling of electricity, carbon dioxide emissions and economical costs. The results from the models have also been analyzed and compared in 8 different scenarios. The scenarios change the configuration of the energy system and weather factor. Examples of scenarios that have been analyzed are optimization of electricity production and change of geographical location.

    The models are built in Matlabs modeling program Simulink and are based on energy balances. Data is gathered with help from HSB Värmland, product sheet of the solar panels (one solar panel is a matrix of several photovoltaics), own measurements, assumptions and similar studies from scientific articles. Carbon dioxide emissions are based on the merit order curve for electricity production (“marginal-energy-principle”).

    An energy system in Karlstad with thermal cooperation, between photovoltaics and exhaust air heat pump, contributes to reduced carbon dioxide emissions by 1239 kg/year (short term) and 448 kg/year (long term). However, it is hard to warrant thermal cooperation from an economical perspective with th. This is because the investment costs of an energy system with thermal cooperation is only allowed to reach a maximum of 7250 kr over 25 years for it to be economically profitable. The amount of electricity that needs to be purchased decreases and the amount of electricity that is sold as well as district heating purchased increases. The yearly average COP of the heat pump increases from 4,56 to 5,30 and the yearly average solar panel efficiency increases from 21,15 to 21,16 %. If the price of electricity increases, then thermal cooperation will become more profitable.

    One scenario from the scenario analysis stands out in comparison with other scenarios due to reduced yearly costs from a cooperating system of 1920 kr/year. This is when the electricity production from the photovoltaics are optimized. However, this scenario requires adjustments in brine flow, heat exchanger area and external cooling which can cause practical complications.

    One scenario has the potential to become economically profitable with the construction of new heating systems. This is when the exhaust air recycling is removed from the heating system. The removal of exhaust air recycling in a cooperating system contributes to lower yearly costs but not as low as a cooperating system with exhaust air recycling. However, this might mean that the construction of new heating systems can be profitable without exhaust air recycling because the investment cost of the exhaust air recycling is removed. Since this study has not taken investment and operating costs of exhaust air recycling into account, further studies are needed to determine this.

    Thermal cooperation is more profitable in warmer countries than Sweden but does not contribute to as low reduction in carbon dioxide emissions. When the energy system is placed in Kiruna, Sweden, it causes both the yearly cost and carbon dioxide emissions to increase. The energy system is placed in Lund, Sweden, yielded similar results as if the system was placed in Karlstad, Sweden. The yearly cost and carbon dioxide emissions decreased when the energy system was placed in Athens, Greece. However, when comparing the energy systems in Athens and Lund, Athens had the lower yearly cost but higher carbon dioxide emissions. Since the energy system placed in Lund contributes to the lowest carbon dioxide emissions in comparison to both Kiruna and Athens then there might be a break point in relation to local climate where the emissions are the lowest possible.

  • 136.
    Greenberg, Larry
    et al.
    Karlstad University, Faculty of Social and Life Sciences, Department of Biology.
    Calles, Olle
    Karlstad University, Faculty of Social and Life Sciences, Department of Biology.
    Andersson, Jonas
    Länsstyrelsen i Värmland.
    Engqvist, Therese
    Länsstyrelsen i Kalmar.
    Effect of trash diverters ad overhead cover on downstream migrating brown trout smolts2012In: Ecological Engineering: The Journal of Ecotechnology, ISSN 0925-8574, E-ISSN 1872-6992, Vol. 48, no November, p. 25-29Article in journal (Refereed)
    Abstract [en]

    Power plant dams constitute barriers for downstream migration by smolts. The purpose of this study was to measure guidance efficiency of existing trash diverters and the use of overhead cover in combination with trash diverters to guide brown trout (

    Salmo trutta L.) smolts away from turbine intakes into trash spillway gates at two power plants in the Emån River, southern Sweden. A total of 44 trout smolts were caught, radio-tagged, released at the two power plants and tracked daily for six weeks. The trash diverter at the lower power plant had a significant guiding effect, as the proportion of smolt that entered the spillway gate was significantly greater than the relative proportion of water that flowed through the gate (52% vs 17%). In contrast, there was no evidence of a guidance effect at upper Finsjö, where the proportion of smolts that entered the spillway gate did not differ significantly from the relative proportion of water that flowed through the gate (0% vs 10%). The lack of a guidance effect at upper Finsjö could not be explained. The effect of overhead cover was tested at the upper power plant as illumination from outdoor, overhead lamps at the power station was believed to attract smolts to the turbine intake. This was accomplishing by setting up and removing a tarpaulin placed between the trash deflector and the turbine intake approximately every 2–5 days for about one month, so that 52.6% of the time the tarpaulin was in place and 47.4% of the time it was not. The presence of the tarpaulin reduced turbine passage, as 31% of the smolts swam through the trash spillway gate instead of the turbines when the tarpaulin was in place, whereas all smolts entered the turbines when no tarpaulin was used. For fish that passed through the turbines, mortality was higher at the upper power plant, equipped with two twin-Francis turbines, than at the lower one, equipped with a single Kaplan turbine.

  • 137.
    Guerra Garlito, Rebeca
    Karlstad University, Faculty of Technology and Science.
    The water treatment system at Djupdalen2007Independent thesis Basic level (degree of Bachelor), 10 points / 15 hpStudent thesis
    Abstract [en]

    This is a project about The Water Treatment System at Djupdalen. The leakage water comes to the Water Treatment System from a deposition plant through the land. The leakage water is characterized by a high concentration of nitrogen and the system is based on biological removing of the nitrogen in the water, by nitrifying and denitrifying bacteria. Four different problems are found in the system: 1. High level of nitrogen concentration in the outgoing water of the system. It should be due to the lack of phosphate in the water, that do not let the bacteria to grow. 2. Low temperature during the most part of the year. Nitrifying and denitrifying bacteria are temperature-dependent, that are very slow at low temperatures. 3. High oxygen concentration in one of the anoxic pond, where the denitrification process take place. This oxygen concentration is too high for denitrifying bacteria to work. 4. The nitrification and denitrification bacteria need to be “old” to work efficiently. They need a surface to attach, because if not they flow with the water and they leave the system. And four possible solutions for the system are presented: 1. Phosphate should be added to the system to let bacteria growth. 2. Store the water at a store pond during the winter months and transport it to the system when the temperature is optimum for the bacteria to work. 3. Add carbon matter to improve the carbon oxidation and to low down the oxygen levels at the anoxic ponds. 4. Two options are presented to improve the system, the first one is based on the construction of a dark wavy bottom in the channel system, which will give a surface for bacteria to attaché, it will produce oxygenation in the water, and it will also improve the water temperature; and the second one is based on the addition of panels made of black material, which will give to bacteria a surface to attach, and improve the water temperature.

  • 138. Gunnarsson, Annika
    Energieffektivisering i två svenska skolor: Kartläggning av skolornas elanvändning samt en undersökning av elbesparingsmöjligheter2014Independent thesis Basic level (degree of Bachelor), 20 credits / 30 HE creditsStudent thesis
  • 139.
    Gunnarsson, Tobias
    Karlstad University, Faculty of Technology and Science, Department of Energy, Environmental and Building Technology.
    Ökad värmeöverföring och isbildning runt rör i vatten för ett värmelager: Transient simulering av olika avstånd mellan kopparrör nedstoppade i vatten inuti en rektangulär låda under en timme2012Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [sv]

    I takt med att världsbefolkningen blir mer och mer medveten om hur deras beteenden påverkar naturen runt omkring ökar också efterfrågan på nyare och effektivare produkter. För att kunna lämna en bättre värld till nästa generation är många konsumenter beredda att ändra sina vanor samtidigt som producenter erbjuder nya varor. Sedan några år forskar ASKO Appliances tillsammans med Kau kring effektivisering av ASKO:s produkter. För att minska förbrukningen av hushållsel har ASKO Appliances satsat på att integrera värmepumpar i sina vitvaror. Värmepumpens stora fördel är att den är den enda kända process som kan recirkulera spill- och omgivningsvärme tillbaka till en värmeproduktionsprocess. Detta gör värmepumpen till ett mycket energieffektivt och miljövänligt uppvärmningsalternativ.Syftet med detta examensarbete är att undersöka den befintliga prototyp av diskmaskin som ASKO Appliances har byggt. Diskmaskinen innehåller en värmepump med tillhörande värmelager som är av vatten. Denna process ska analyseras för att sedan försöka bygga en numerisk modell som kan efterlikna den befintliga processen. Den numeriska modellen ska visa hur olika mått på värmelager och kopparrör i värmelager ger olika energiflöden och isbildningsförlopp. Dessutom ska den undersöka ifall en metallvägg i värmelagret ger några fördelar. För att verifiera den numeriska modellen jämförs isbildningen med isbildningen i värmelagret. Slutligen, med underlag från den numeriska modellen, ska sedan ett nytt värmelager till nästa prototyp föreslås. COMSOL Multiphysics 4.2 användes för att bygga den numeriska modellen.Undersökningen av prototypdiskmaskinen består av att mäta temperaturer på alla ställen i processen samtidigt som högtrycket och lågtrycket mäts. Dessutom mäts energibehovet för värmepumpens kompressor och diskmaskinens elelement. Detta för att visa hur processen fungerar.Resultatet visar att isbildningen i den numeriska modellen har god överensstämmelse med isbildningen i prototypens värmelager. Mätvärden från undersökningen demonstrerar goda energibesparingar genom att energibehovet vid uppvärmning minskar med 45 % (0,3 kWh) gentemot att använda ett elelement.Ett förslag till nytt värmelager tas fram genom att testa 170 olika numeriska modeller. Om inte lådans yttre geometrier, förutom tjockleken, är en begränsande faktor så är en låda som är c:a 16 mm tjock, 40 mm mellan rören och att kopparrören är i kontakt med en metallvägg en bra avvägd konfiguration.

  • 140.
    Gustafsson, Fredrik
    Karlstad University, Division for Engineering Sciences, Physics and Mathematics.
    Gasturbinventil2010Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
  • 141.
    Gustafsson, Marcus
    Karlstad University, Faculty of Health, Science and Technology (starting 2013).
    Batterilager i kommersiella fastigheter: Lönsamhetsanalys av batterilager med hjälp av blandad heltalsprogrammering2017Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The world has seen a rapid deployment of distributed and time-varying renewable energy systems (RES) within the electricity grids for the past 20 years, especially from wind and solar power. The deployment RES is expected to increase even more as world organizations and nations will continue the phase-out of fossil fuels as the main source of energy for electricity production. As large scale power plants reliant on fossil fuels will shut down it will be harder for the system to balance production and demand. At the same time, time-varying production might have a negative effect on the grid stability which has spurred an increased interest in flexibility on the demand side and a call for technologies and strategies that can create balance on the grid.

    Energy storage, especially electrochemical battery storage, is seen as a part of a bigger solution to the problems that comes with intermittent energy production. Battery storage has had a fast technological development and a sharp downtrend in pricing the latest ten years and the costs are expected to keep on decreasing. For battery storage to be a serious contender on the electricity market there is a need to understand if and when an investment in this technology might give a positive outcome. The aim of this study has therefore been to analyse the profitability of battery storage within commercial real estate today, and in the oncoming 10-15 years on the Swedish electricity market.

    The study has, using mixed integer linear programming (MILP) within MATLAB, created a model which optimally schedules power flows for buildings that has a battery system and its own electricity production. The model has in turn been used to evaluate the economical possibilities that exist with a battery system within commercial real estate under various different scenarios that looks into pricing structures on electricity and demand, integration with and without solar panels, different battery sizes and system lifetimes.

    The results show that there is currently no profitability to invest in a battery system for the specific buildings analysed in this study. While break-even is possible just a couple of years from now, a high profitability will not be reached even with the future downtrend in battery prices under the current electricity market circumstances. A smaller battery system with a capacity of 28 kWh could give an internal rate of return (IRR) of 1 % year 2020. Larger battery systems are generally not cost-effective when compared to smaller battery systems when its primary purpose is utilized for demand reduction. Highest return with today’s electricity and utility pricing is 4-5 % somewhere between 2025 and 2030. However, if the market goes towards exclusively time-of-use billing structures on electricity and higher demand charges, the IRR can reach towards 15-18 % between 2025 and 2030. 

  • 142.
    Gustavsson, Christer
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences (from 2013).
    Added value from biomass by broader utilization of fuels and CHP plants2016Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The present work, where additional value-creating processes in existing combined heat and power (CHP) structures have been examined, is motivated by a political- and consumer-driven strive towards a bioeconomy and a stagnation for the existing business models in large parts of the CHP sector.

    The research is based on cases where the integration of flash pyrolysis for co-production of bio-oil, co-gasification for production of fuel gas and synthetic biofuels as well as leaching of extractable fuel components in existing CHP plants have been simulated. In particular, this work has focused on the CHP plants that utilize boilers of fluidized bed (FB) type, where the concept of coupling a separate FB reactor to the FB of the boiler forms an important basis for the analyses. In such dual fluidized bed (DFB) technology, heat is transferred from the boiler to the new rector that is operating with other fluidization media than air, thereby enabling other thermochemical processes than combustion to take place. The result of this work shows that broader operations at existing CHP plants have the potential to enable production of significant volumes of chemicals and/or fuels with high efficiency, while maintaining heat supply to external customers.

    Based on the insight that the technical preconditions for a broader operation are favourable, the motivation and ability among the incumbents in the Swedish CHP sector to participate in a transition of their operation towards a biorefinery was examined. The result of this assessment showed that the incumbents believe that a broader operation can create significant values for their own operations, the society and the environment, but that they lack both a strong motivation as well as important abilities to move into the new technological fields.

    If the concepts of broader production are widely implemented in the Swedish FB based CHP sector, this can substantially contribute in the transition towards a bioeconomy.

  • 143.
    Gustavsson, Christer
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences (from 2013).
    Hulteberg, Christian
    Lund University.
    Co-production of gasification based biofuels in existing combined heat and power plants - Analysis of production capacity and integration potential2016In: Energy Journal, ISSN 0195-6574, E-ISSN 1944-9089, Vol. 111, no September, p. 830-840Article in journal (Refereed)
    Abstract [en]

    Solid fuel fired fluidized bed (FB) boilers are common in combined heat and power (CHP) plants in district heating- and process industry. In this study, utilization of such FB boilers for production of syngas in dual fluidized bed gasifiers and subsequent catalytic biofuel production to substitute natural gas (SNG), methanol (MeOH) and Fischer-Tropsch fuel (FT) has been examined. Based on the hypothesis that waste-heat and tail gas from the biofuel processes can be utilized in the CHP plant, process configurations aiming for operationally robustness and low investment cost rather than maximum stand-alone efficiency have been explored and implemented in actual industrial cases and over the full operating range of the boilers. The results of the study show that significant improvements of overall efficiency can be achieved by integration of the biofuel processes in the CHP plants and that a relatively high biofuel production capacity can be achieved. SNG showed the highest obtainable efficiency and production capacity of the studied biofuels, whereas the FT process showed largest increase in terms of efficiency when integrated in the CHP plant, compared to its stand-alone efficiency.

  • 144.
    Gustavsson, Christer
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
    Nilsson, Lars
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
    Addition/Correction: Co-production of pyrolysis oil in district heating plants: Systems analysis of dual fluidized-bed pyrolysis with sequential vapor condensation (Energy and Fuels (2013) 27:9 (5313?5319) DOI: 10.1021/ef401143v)2013In: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 27, no 10, p. 6333-6333Article in journal (Refereed)
  • 145.
    Gustavsson, Christer
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Physics.
    Nilsson, Lars
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
    Co-production of pyrolysis oil in district heating plants: Systems analysis of dual fluidized-bed pyrolysis with sequential vapor condensation2013In: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 27, no 9, p. 5313-5319Article in journal (Refereed)
    Abstract [en]

    Flash pyrolysis of biomass yields a liquid applicable as a fuel oil substitute and as a basis for production of chemicals and fuels. Biomass, being a renewable resource, is foreseen to be in increasing demand. An increased usage may lead to scarcity of biomass and emphasizes the need for high-efficiency conversion processes. In this study, the efficiency and capacity aspects of an integration of pyrolysis oil production with a district heating plant by means of dual fluidized-bed technology has been modeled. Further, fractional condensation of the pyrolysis vapors has been applied, enabling part of the condensation energy to be recovered. The concept shows potential for significant pyrolysis oil production while keeping the delivered power and heat constant. The use of excess heat from the pyrolysis production in the district heating net results in a 10% higher overall efficiency than production without heat supply to the district heating net.

  • 146.
    Gustavsson, Christer
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
    Nilsson, Lars
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
    Renström, Roger
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
    Syngas as an Additional Energy Carrier in the Pulp and Paper Industry: A Mill-Wide System Analysis of a Combined Drying Concept, Utilizing On-Site Generated Gas and Steam2014In: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 28, no 9, p. 5841-5848Article in journal (Refereed)
    Abstract [en]

    Large amounts of thermal energy are required for different unit operations in the pulp and paper industry. Typically, this energy is distributed by means of steam. In this study, introduction of in-situ-generated syngas as an energy carrier in parallel to the predominant steam has been investigated. The examined systems use dual fluidized-bed gasification integrated with a solid fuel boiler of a paper mill together with impingement drying in combination with cylinder drying, a concept enabling higher specific drying rates. The studied systems exhibit reduced overall energy use when compared to the present situation with conventional steam-heated cylinder drying. Cold tar cleaning by condensation/absorption and firing of the syngas in a gas turbine followed by utilization of the exhaust gases for drying are interesting options because this results in reduced biomass consumption with maintained power production.

  • 147.
    Gustavsson, Johny
    Karlstad University, Faculty of Technology and Science, Department of Energy, Environmental and Building Technology.
    Påverkan på lönsamhetsberäkningen för solcellsanläggningar vid förbättrad prediktering av elutbytet2015Independent thesis Advanced level (degree of Master (Two Years)), 300 HE creditsStudent thesis
    Abstract [en]

    Intergovernmental Panel on Climate Change, IPCC finds that the conditions for life on Earth are changing and that this change derives most likely to humans. The consequences claimed by other successful research initiatives to be of such magnitude that it is justified to speak of a new geological epoch, the Anthropocene. A significant driver of this change are human emissions of greenhouse gases, which to the part can be attributed to an electricity need. Photovoltaic is a technology with which electricity can be produced with significantly less greenhouse gas emissions than conventional techniques. The expansion of solar energy is thus a desirable environmental measure. The profitability of solar electricity has been an obstacle for the expansion, in particular for commercial establishments. In a sensitivity analysis performed in a study from 2014 which examines the profitability of photovoltaic (PV) plants in Sweden shows that the estimated production of electricity in the first year is the factor, second only to the initial investment cost, which has the greatest impact on the profitability calculations. In calculating the PV electricity different methods with different accuracy are used. The most accurate method involves the use of commercial software packages like PVsyst, Polysun, and PV * SOL. In a study from 2014 the accuracy of some of the above mentioned program packages was compared and notes a discrepancy in the order of seven to nine percent. According to the same report, the majority of this miscalculated power generation is attributable to the solar cell model. The solar cell model is the part of the software packages that simulate the solar cell power generation based on values of solar radiation and the solar cell temperature. There are several different solar cell models, some of which are claimed to be more accurate than others. The software package that is likely to be the most prevalent in the planning of photovoltaic plants, PVsyst, does not use the variant of the solar cell model that is claimed to be the most accurate. This thesis investigates how the implementation of a novel and more accurate solar cell model in PVsyst would affect the profitability calculations for commercial PV plants in Sweden. The work can be divided into two parts, where the first part generates input data to the other. In the first part, the more accurate solar cell model and the solar cell model that can be found in PVsyst are programmed in MATLAB. The accuracy of reconstruction of power generation based on measurement data is calculated and the difference between the solar cell models are input to the second part of the work, the profitability calculations.  The profitability calculations in this work springs from the outer conditions identified for a real case where the interested party consists of a non - private operator with a ground area available for a solar installation. The results show that the new solar cell model is two percent more carefully when calculating the electricity generation, which corresponds in order of a quarter of the total discrepancy of prediction tool PVsyst. This does not strike through in the profitability calculation to any significant extent but would the whole discrepancy be eliminated it would allow the use of a discount rate increased by about half a percent. The work also shows that commercial photovoltaic systems today can be profitable. A positive net present value was calculated based on a discount rate of five percent for a fix installation that cover the whole area. 

  • 148.
    Haas, Jan
    Karlstad University.
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    Haas, Jan
    Karlstad University.
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