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  • 301.
    Eriksson, Gunnar
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Residues from biochemical production of transport biofuels in Northern Europe: combustion properties and applications2009Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    Residues from biochemical production of liquid transport biofuels will probably become available for energy use if more gasoline and diesel is substituted. For processes used in northern Europe they amount to 35-65 % of the feedstock energy and despite interest from energy companies, their fuel properties are largely unknown. Combustion-relevant material properties have been characterized and fuel-specific combustion properties determined for powder-, grate- and fluidized bed combustion. Suitable combustion applications have been identified. A techno-economic evaluation of utilization of a selected residue for supplying process heat and electricity to the transport biofuel production, combined with sale of surplus energy has been done. Residues studied are rape-seed meal (RM) from biodiesel production, wheat distillers dried grain with solubles (wheat DDGS) from grain-based ethanol production and hydrolysis residue (HR) from wood-based ethanol production. For RM and wheat DDGS, mixtures with typical forest- and agricultural fuels were also studied. Combustion experiments were performed in a fluidized (quartz) bed (5 kW), an under-fed pellet burner (12 kW), and in a powder burner (150 kW).The calorific value for HR was higher than for wood, for RM and wheat DDGS it was similar to wood. More char was produced from HR, otherwise TGA results showed that thermal kinetics was similar to wood for all fuels. All pulverized residues had better feeding properties than wood powder. While RM and wheat DDGS ash contents were higher than for most common forest and also for some agricultural fuels, HR mostly had very low contents of ash, alkali, Cl, S and N. RM and DDGS had high concentrations of S, N, K and P compared to most other biomass fuels. RM had higher Ca and Mg concentrations than DDGS. The Cl content of wheat DDGS was similar to wheat straw, while RM had a lower Cl content, similar to wood. Combustion of all pulverized residues was stable with CO emissions not higher than for wood powder. While the bed agglomeration tendency of RM was low and comparable to many forest fuels the wheat DDGS bed agglomeration tendency was high and comparable to wheat straw. The K, P and Si contents of wheat DDGS formed layers of K-phosphates/silicates on the quartz grain particles, with low melting temperatures and therefore sticky, resulting in bed agglomeration. For RM, this effect was mitigated by the considerable Ca and Mg concentrations, making the layers formed less sticky, despite the high K and P concentrations. For basically the same reason, the slag formation tendency of RM was moderate and comparable to many forest fuels while wheat DDGS had a slag formation tendency which was even higher than for typical wheat straw. HR had very low bed agglomeration and slagging tendencies.For RM and wheat DDGS, emissions of NO and SO2 were generally high, for HR considerably lower. While HCl emissions for RM were low, they were relatively high for fluidized bed combustion of wheat DDGS. Particle emissions from RM and wheat DDGS were generally high. For powder combustion of RM and wheat DDGS, particle emissions were 15-20 times higher than for wood. The particle emissions from combustion of HR were generally low. For fluidized bed- and grate combustion of RM the finer particles (< 1 μm) contained mainly alkali sulfates. RM addition to bark tended to lower the particle Cl concentrations, potentially lowering the risk of high-temperature corrosion. For fluidized bed combustion of wheat DDGS and wheat DDGS-mixtures the finer particles contained mainly K and S. The Cl concentrations of the fine particles in fluidized bed combustion were reduced when wheat DDGS where added to logging residues and wheat straw in fluidized bed combustion. In grate combustion the Cl- and P-concentrations in the finer particles during combustion of the wheat DDGS-mixtures were considerable higher than during fluidized bed combustion. The fine particles from powder combustion of RM mainly contained P and K, while they mainly contained K, P, Cl, Na and S from wheat DDGS (apart from C and O).A possible use of RM is as a sulfur-containing additive to biomass fuels rich in Cl and K in large-scale fluidized-bed and grate combustors for avoiding ash-related operational problems in fluidized beds and grate combustors originated from high KCl concentrations in the flue gases. Due to its high slagging and bed agglomeration tendencies, the best use of wheat DDGS may be to mix it with other fuels, preferably with high Ca and Mg contents (e.g. woody biomass fuels), so that only a minor fraction of the total ash-forming elements is contributed by the wheat DDGS. Because of their high N- and S contents, RM and wheat DDGS require applications with flue-gas cleaning, economically viable at large-scale. Powder combustion of RM and wheat DDGS should be used with caution, as potassium phosphate particles have low melting temperatures and could therefore increase the risk of deposit formation. Use of HR in small-scale pellet appliances is an interesting option due to low emissions, low ash content and low slagging tendency. While most large-scale combustion uses of HR would be feasible, the low ash and alkali contents and stable powder combustion of HR may be better exploited in a combined-cycle process, as the alkali content can be kept sufficiently low for use in robustgas turbines, simplifying the gas cleaning.In the techno-economic assessment, residue (HR) was assumed to be combusted on site, to supply process steam and electricity to the liquid biofuel production (wood-based ethanol) with surplus residue either sold as solid fuel or used for additional heat and power generation. With a combined cycle to increase electricity production, a location with a large district heating base load is not needed. As electricity replaced is largely generated with fossil fuels, a combined cycle is significantly more effective as a climate mitigation measure than a steam-cycle only, with about 25 percent greater reduction in CO2 emissions per litre of ethanol produced. While it is generally accepted that energy use of the residue is important to the process economy and environmental benefits of ligno-cellulosic ethanol production, it can be concluded from this study that the choice of integrated process design has a significant impact on CO2 emissions.

  • 302.
    Eriksson, Gunnar
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Grimm, Alejandro
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Skoglund, Nils
    Umeå universitet.
    Boström, Dan
    Umeå universitet.
    Öhman, Marcus
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Combustion and fuel characterisation of wheat distillers dried grain with solubles (DDGS) and possible combustion applications2012Ingår i: Fuel, ISSN 0016-2361, E-ISSN 1873-7153, Vol. 102, s. 208-220Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The present transition to a sustainable global energy system requires that biomass is increasingly combusted for heat and power production. Agricultural fuels considered include alkali-rich fuels with high phosphorus content. One such fuel is wheat distiller’s dried grain with solubles (wheat DDGS) from wheat-based ethanol production. Further increases in ethanol production may saturate the current market for wheat DDGS as livestock feed, and fuel uses are therefore considered. Fuel properties of wheat DDGS have been determined. The ash content (5.4. ± 1.6 %wt d.s.) is similar to many agricultural fuels. In comparison to most other biomass fuels the sulphur content is high (0.538 ± 0.232 %wt d.s.), and so are the contents of nitrogen (5.1 ± 0.6 %wt d.s.), phosphorus (0.960. ± 0.073 %wt d.s.) and potassium (1.30 ± 0.35 %wt d.s.). To determine fuel-specific combustion properties, wheat DDGS and mixes between wheat DDGS and logging residues (LR 60 %wt d.s. and DDGS 40 %wt d.s.), and wheat straw (wheat straw 50 %wt d.s., DDGS 50 %wt d.s.) were pelletized and combusted in a bubbling fluidised bed combustor (5 kW) and in a pellets burner combustor (20 kW). Pure wheat DDGS powder was also combusted in a powder burner (150 kW). Wheat DDGS had a high bed agglomeration and slagging tendency compared to other biomass fuels, although these tendencies were significantly lower for the mixture with the Ca-rich LR, probably reflecting the higher first (solid) melting temperatures of K–Ca–Mg-phosphates compared to K-phosphates. Combustion and co-combustion of wheat DDGS resulted in relatively large emissions of fine particles (<1 μm) for all combustion appliances. For powder combustion PMtot was sixteen times higher than from softwood stem wood. While the Cl concentrations of the fine particles from the LR–wheat DDGS-mixture in fluidised bed combustion were lower than from combustion of pure LR, the Cl- and P-concentrations were considerably higher from the wheat DDGS mixtures combusted in the other appliances at higher fuel particle temperature. The particles from powder combustion of wheat DDGS contained mainly K, P, Cl, Na and S, and as KPO3 (i.e. the main phase identified with XRD) is known to have a low melting temperature, this suggests that powder combustion of wheat DDGS should be used with caution. The high slagging and bed agglomeration tendency of wheat DDGS, and the high emissions of fine particles rich in K, P and Cl from combustion at high temperature, mean that it is best used mixed with other fuels, preferably with high Ca and Mg contents, and in equipment where fuel particle temperatures during combustion are moderate, i.e. fluidised beds and possibly grate combustors rather than powder combustors.

  • 303. Eriksson, Gunnar
    et al.
    Hedman, Henry
    Energy Technology Centre, Piteå.
    Boström, Dan
    Energy Technology and Thermal Process Chemistry, Department of Applied Physics and Electronics, Umea University.
    Backman, Rainer
    Energy Technology and Thermal Process Chemistry, Department of Applied Physics and Electronics, Umea University.
    Pettersson, Esbjörn
    Öhman, Marcus
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Combustion characterization of rapeseed meal and possible combustion applications2009Ingår i: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 23, nr 8, s. 3930-3939Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A future shortage of biomass fuel can be foreseen. The production of rapeseed oil for a number of purposes is increasing, among others, for biodiesel production. A byproduct from the oil extraction process is rapeseed meal (RM), presently used as animal feed. Further increases in supply will make fuel use an option. Several energy companies have shown interest but have been cautious because of the scarcity of data on fuel properties, which led to the present study. Combustion-relevant properties of RM from several producers have been determined. The volatile fraction (74 ± 0.06%wtds) is comparable to wood; the moisture content (6.2−11.8%wt) is low; and the ash content (7.41 ± 0.286%wtds) is high compared to most other biomass fuels. The lower heating value is 18.2 ± 0.3 MJ/kg (dry basis). In comparison to other biomass fuels, the chlorine content is low (0.02−0.05%wtds) and the sulfur content is high (0.67−0.74%wtds). RM has high contents of nitrogen (5.0−6.4%wtds), phosphorus (1.12−1.23%wtds), and potassium (1.2−1.4%wtds). Fuel-specific combustion properties of typical RM were determined through combustion tests, with an emphasis on gas emissions, ash formation, and potential ash-related operational problems. Softwood bark was chosen as a suitable and representative co-combustion (woody) fuel. RM was added to the bark at two levels: 10 and 30%wtds. These mixtures were pelletized, and so was RM without bark (for durability mixed with cutter shavings, contributing 1%wt of the ash). Each of these fuels was combusted in a 5 kW fluidized bed and an underfed pellet burner (to simulate grate combustion). Pure RM was combusted in a powder burner. Emissions of NO and SO2 were high for all combustion tests, requiring applications with flue gas cleaning, economically viable only at large scale. Emissions of HCl were relatively low. Temperatures for initial bed agglomeration in the fluidized-bed tests were high for RM compared to many other agricultural fuels, thereby indicating that RM could be an attractive fuel from a bed agglomeration point of view. The results of grate combustion suggest that slagging is not likely to be severe for RM, pure or mixed with other fuels. Fine-mode particles from fluidized-bed combustion and grate combustion mainly contained sulfates of potassium, suggesting that the risk of problems caused by deposit formation should be moderate. The chlorine concentration of the particles was reduced when RM was added to bark, potentially lowering the risk of high-temperature corrosion. Particle emissions from powder combustion of RM were 17 times higher than for wood powder, and the fine-mode fraction contained mainly K-phosphates known to cause deposits, suggesting that powder combustion of RM should be used with caution. A possible use of RM is as a sulfur-containing additive to biomass fuels rich in Cl and K for avoiding ash-related operational problems in fluidized beds and grate combustors originated from high KCl concentrations in the flue gases.

  • 304. Eriksson, Gunnar
    et al.
    Hedman, Henry
    Energy Technology Centre, Piteå.
    Öhman, Marcus
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Boström, Dan
    Energy Technology and Thermal Process Chemistry, Umeå University.
    Pettersson, Esbjörn
    Pommer, Linda
    Energy Technology and Thermal Process Chemistry, Umeå University.
    Lindström, Erica
    Energy Technology and Thermal Process Chemistry, Umeå University.
    Backman, Rainer
    Energy Technology and Thermal Process Chemistry, Umeå University.
    Öhman, Rikard
    Energy Technology Centre, Piteå.
    Förbränningskarakterisering av rapsmjöl och förslag till optimalt nyttjande i olika förbränningsanläggningar2007Rapport (Övrigt vetenskapligt)
    Abstract [sv]

    Effektiva värmevärdet hos rapsmjöl är 18,2 +/- 0,3 MJ/kg TS och askhalten varierar mellan 7-8 %. Bränslet har högt N- och S-innehåll, och bränslet är rikt på K, P, Ca och Mg. Partikelemissionerna från fluidbäddseldning och rosterförbränning med rapsmjölsblandningar var ungefär dubbelt så höga som från barkförbränning. Vid pulverförbränning av rapsmjöl ökade partikelemissionerna med en faktor 17 jämfört med träpulver. De höga NOx och SOx emissionerna från rapsmjölsförbränning innebär att materialet bör utnyttjas i storskaliga anläggningar med extern svavel.- eller NO-rening, eller i relativt låga inblandningsgrader i andra bränslen. Mindre anläggningar med enbart cyklonrening är olämpliga på grund av de höga stofthalterna. Rapsmjöl torde vara ett intressant sameldningsbränsle vid roster- och fluidbäddseldning med klor- och kaliumrika skogs- och åkerbränslen då rapsmjöl eventuellt skulle kunna användas som svaveladditiv för reduktion av klorinducerad korrosion på t ex överhettare. Slaggningstendensen torde minska vid inblandning av rapsmjöl i båda dessa bränslekategorier och bäddagglomereringstendensen torde minska vid inblandning av rapsmjöl i åkerbränslen.

  • 305.
    Eriksson, Gunnar
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Jacobsson, Jan-Erik
    Mekanismer för spontan spridning av lönsam energieffektiv teknik1998Rapport (Övrigt vetenskapligt)
  • 306.
    Eriksson, Gunnar
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Kjellström, Björn
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Assessment of combined heat and power (CHP) integrated with wood-based ethanol production2010Ingår i: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 87, nr 12, s. 3632-3641Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A techno-economic assessment is made of wood-based production of ethanol, where the by-products are used for internal energy needs as well as for generation of electricity, district heat and pelletised fuel in different proportions for external use. Resulting ethanol production costs do not differ much between the options but a process where electricity generation is maximised by use of the solid residues as fuel for a combined cycle is found to give 20% more reduction of green-house gas emissions per liter of ethanol produced than the other options. Maximising electricity generation at the expense of district heat generation also allows more freedom when suitable sites for ethanol plants are looked for. Use of gasified biofuel for a combined cycle power plant is a demonstrated technology, however, the low ash and alkali content of the hydrolysis residue may allow direct combustion in the gas turbine topping cycle. This would reduce the necessary investment considerably. The potential advantages of using a combined cycle for maximising the electric power output from an energy combinate, producing ethanol and electricity from biomass, justifies further exploration of the possibilities for using hydrolysis residue directly as gas turbine fuel.

  • 307.
    Eriksson, Gunnar
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Kjellström, Björn
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Corrigendum to: Assessment of combined heat and power (CHP) integrated with wood-based ethanol production [Applied Energy 87 (12) (2010) 3632-3641]2011Ingår i: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 88, nr 5, s. 1997-1998Artikel i tidskrift (Övrigt vetenskapligt)
  • 308. Eriksson, Gunnar
    et al.
    Kjellström, Björn
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Lundqvist, Björn
    Paulrud, S.
    SLU, Umeå.
    Combustion of wood hydrolysis residue in a 150 kW powder burner2004Ingår i: Fuel, ISSN 0016-2361, E-ISSN 1873-7153, Vol. 83, nr 11-12, s. 1635-1641Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A combustion test has been made with residues from hydrolysis of wood for fuel ethanol production. A 150 kW powder burner was used. Fuel feeding and combustion were stable. The average concentration of CO in the stack gas was 8 mg/MJ, the average concentration of NOx was 59 mg/MJ and the average total hydrocarbon concentration was below 1 ppm, at an average O2-concentration of 4.6%. The low contents of potassium and sodium in the hydrolysis residue make the material attractive as a gas turbine fuel and the conclusion of this test is that direct combustion may be a feasible approach for gas turbine applications.

  • 309.
    Eriksson, Gunnar
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Nordgren, Daniel
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Berg, Magnus
    Vattenfall Research & Development.
    New experimental characterisation methods for solid biomass fuels to be used in combined heat and power generation2008Ingår i: Proceedings: World Bioenergy 2008 : [Conference & Exhibition on Biomass for Energy, 27 - 29 May 2008, Jönköping - Sweden] / [ed] Johan Vinterbäck, Stockholm: Swedish Bioenergy Association (SVEBIO) , 2008, Vol. Poster sessions, s. 264-273Konferensbidrag (Refereegranskat)
    Abstract [sv]

    Att ersätta fossilbränslena kommer att öka efterfrågan på okonventionella biobränslen. Det blir viktigt att kunna karakterisera bränslet för att förutse förbränningsegenskaper och underlätta valet av tillämpningar är viktigt för att undvika dyrbara och tidsödande misstag. De traditionella metoderna är i huvudsak utvecklade för kol. Därför finns det ett behov av metoder som är speciellt utformade med tanke på biobränslen. Detta arbete utgör en översikt av metoder för bränslekarakterisering av biomassa som utvecklats under de sista tio åren. De relevanta metoderna behandlar: 1) Bränslehantering: malbarhet, erosiva och abrasiva egenskaper. 2) Bränslekarakteriseirng: devolatilsering (viktigt för antändning och flamstabilitet), tid för koksutbränning. 3) Risker för slaggbildning och beläggningsbildning vid förbränning: bildning av askpartiklar, askpartiklarnas storleksfördelning, asksammansättning, temperaturer för smältning och förgasning, slaggbildning från bottenaska, minskning av riskerna för askrelaterade problem genom inblandning av andra bränslen, användning av bränsleadditiv eller lämpligt val av förbränningstillämpningar för det specifika bränslet. De viktigaste slutsatserna är: 1) Det finns behov av en metod att mäta malbarheten som tar hänsyn till elförbrukningen. Hardgrove index för malbarhet som används för kol är irrelevant för biobränslen; 2) Det finns utvecklingsbehov när det gäller användarvänliga och kostnadseffektiva metoder för att mäta benägenheten för slaggbildning och beläggningsbildning, och för mätning av kinetiken för avgasning och koksförbränning med de höga upphettningshastigheterna i fluidbäddar och pulverbrännare.

  • 310.
    Eriksson, Gunnar
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Tiberg, Nils
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser.
    Klarar Luleå miljömålen?: utsläpp av koldioxid och klimatskydd i Luleå kommun1995Rapport (Övrigt vetenskapligt)
  • 311.
    Eriksson, Gunnar
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Tiberg, Nils
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser.
    Delin, Staffan
    Luleå tekniska universitet.
    Fysisk redovisning för Norrbottens län och två perspektiv på bärkraftig utveckling1996Rapport (Övrigt vetenskapligt)
  • 312.
    Espin Delgado, Angela
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Camarillo-Penaranda, Juan Ramón
    Universidad de los Andes, Bogota, Colombia.
    Ramos, Gustav
    Universidad de los Andes, Bogota, Colombia.
    Characterization of Phase-Angle Jump in RadialSystems using Incremental Voltage Phasors2019Ingår i: IEEE transactions on industry applications, ISSN 0093-9994, E-ISSN 1939-9367, Vol. 55, nr 2, s. 1117-1125Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A methodology for characterizing the phase-angle jump associated with voltage sags in radial systems using incremental voltage quantities is presented in this paper. The incremental voltage phasor is defined as the difference between the pre-fault and the during-fault voltage phasors at the point of common coupling. The characteristics of this phasor are stated for different fault conditions as a function of system impedances. Both fault impedance and source neutral grounding impedance are considered in the analysis. Furthermore, the vector representation of phasors and impedance diagrams are employed as a graphical aid for understanding the incremental quantities behavior as a function of the system parameters. An algorithm for fault classification is also presented. Finally, the theoretical analysis is confirmed using real data provided by the Department of Energy and the Electric Power Research Institute. The results of this paper can be useful in future works for fault classification and fault location.

  • 313. Esteves, Jorge
    et al.
    Brekke, Karstein
    Niall, Kevin
    Delfant, Maurizio
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Voltage quality monitoring, dips classification and responsibility sharing2011Ingår i: Proceeding of the International Conference on Electrical Power Quality and Utilisation, EPQU, IEEE Communications Society, 2011Konferensbidrag (Refereegranskat)
    Abstract [en]

    CEER and EURELECTRIC cooperation in the field of quality of electricity supply, involving joint meetings and the participation at the relevant CENELEC Technical Committee, contributed to the results attained in the recent publication of the EN 50160:2010 edition that includes a new voltage dips classification table allowing harmonisation at European level on voltage dips data collection. The generalisation of voltage quality monitoring data publication all over Europe will allow the definition of responsibility sharing between the different involved stakeholders and the evolution of voltage quality regulation applied at national level. Examples from Sweden and Italy are briefly presented in this paper.

  • 314.
    Etherden, Nicholas
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Increasing the hosting capacity of distributed energy resources using storage and communication2014Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [sv]

    Avhandlingen studerar hur existerande elnät kan ta emot mer produktion från förnyelsebara energikällor som vindkraft och solenergi. En metodik utvecklas för att objektivt kvantifiera mängden ny produktion som kan tas emot av ett nät. I flera fallstudier på verkliga nät utvärderas potentiella vinster med energilager, realtids gränser för nätets överföringsförmåga, och koordinerad kontroll av småskaliga energiresurser. De föreslagna lösningarna för lagring och kommunikation har verifierats experimentellt i en forskning, utveckling och demonstrationsanläggning i Ludvika.

  • 315.
    Etherden, Nicholas
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Increasing the hosting capacity of distributed energy resources using storage and communication2012Licentiatavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [sv]

    Användningen av el från förnyelsebara energikällor som vind och sol kommer att påverka elnätet, som sätter en gräns för hur mycket distribuerad energiproduktion som kan anslutas. Investeringar i storskalig energilager och användning av modern kommunikationsteknologi gör det möjligt att öka andelen förnyelsebarenergi genom att nätet kan drivas närmare sina gränser. Elnät med sådana nya tekniker kallas ofta för ”Smarta Elnät". Implementering av sådana smarta elnät kan vara ett alternativ till traditionell nätplanering och åtgärder som utbyte av transformatorer eller konstruktion av nya kraftledningen.Nätets acceptansgräns är ett objektivt mått för att bestämma gränsen för nätets förmåga att integrera ny förbrukning eller produktion. Målet är att skapa större transparens och bidra till ett bättre faktaunderlag i diskussioner mellan nätoperatörer och ägare av distribuerade energiresurser. Denna avhandling utökar acceptansgränsmetoden för tillämpning med energilager och produktions nedstyrning och utvecklar ytterligare begrepp så som acceptansgränsen koefficienten.Forskningen visar hur varierbarheten hos olika förnyelsebara energikällor samverkar med förbrukningen och påverkar nätets acceptansgräns. Flera fallstudier från verkliga elnät och med uppmätt produktion och konsumtion presenteras. Fokus är på hur den tillåtna mängden förnyelsebara energikällor kan ökas med hjälp av energilagring, kontrollerad produktionsnedstyrning och med avancerad distribuerade skydd och kontroll applikationer.

  • 316.
    Etherden, Nicholas
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Dimensioning of Energy Storage for Increased Integration of Wind Power2013Ingår i: 2013 IEEE Power and Energy Society Generl Meeting (PES), Piscataway, NJ: IEEE Communications Society, 2013Konferensbidrag (Refereegranskat)
  • 317.
    Etherden, Nicholas
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Dimensioning of energy storage for increased integration of wind power2013Ingår i: IEEE Transactions on Sustainable Energy, ISSN 1949-3029, E-ISSN 1949-3037, Vol. 4, nr 3, s. 546-553Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Energy storage can potentially allow for more production from renewable resources into existing grids. A methodology to quantify grid limitations and dimension battery energy storage systems is presented in this paper. By use of grid consumption and production data, the hosting capacity methodology is developed as a general framework for storage dimensioning that can be applied by grid operators. The method is successfully applied to an existing subtransmission grid; actual hourly production and consumption data during a two-year period is used. The role of a storage system compared to other means to handle overloading is studied. It is found that about one third of overloading instances are suitable to handle with a battery energy storage system. After this, diminishing returns per unit of storage capacity are shown to occur.

  • 318.
    Etherden, Nicholas
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Effect of large scale energy storage on CO2 emissions in Scandinavian peninsula2012Konferensbidrag (Övrigt vetenskapligt)
  • 319.
    Etherden, Nicholas
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Increasing the hosting capacity of distribution networks by curtailment of renewable energy resources2011Ingår i: 2011 IEEE PES Trondheim PowerTech: The Power of Technology for a Sustainable Society, POWERTECH 2011; Trondheim; 19 June 2011 through 23 June 2011, Piscataway, NJ: IEEE Communications Society, 2011Konferensbidrag (Refereegranskat)
    Abstract [en]

    This paper applies the hosting-capacity method to a realistic distribution system. Under given circumstances the hosting capacity for Distributed Energy Resources (DER) identifies the degree of DER in power grid that can be accepted without endangering the reliability or quality of power. In this case study two limits setting the hosting capacity were evaluated: overvoltage and overcurrent. Finally it is examined to what extent the hosting capacity can be increased with use of real-time information and calculation of dynamic performance indications that govern the hosting capacity. It is shown that there is significant potential for increasing the hosting capacity without having to build new lines

  • 320.
    Etherden, Nicholas
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Overload and overvoltage in low-voltage and medium-voltage networks due to renewable energy: some illustrative case studies2012Ingår i: 2nd IEEE PES International Conference and Exhibition on Innovative Smart Grid Technologies (ISGT Europe), Piscataway, NJ: IEEE Communications Society, 2012Konferensbidrag (Refereegranskat)
    Abstract [en]

    This paper presents the use of curtailment to allowmore wind or solar power to be connected to a distributionnetwork when overcurrent or overvoltage set a limit. For fourcase studies, all based on measurements, the gain in producedenergy is calculated. It is shown that the curtailment method hasa large impact on this gain. The paper further discusses details ofthe curtailment algorithm and the communication needs as wellas some further applications of curtailment.

  • 321.
    Etherden, Nicholas
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Overload and overvoltage in low-voltage and medium-voltage networks due to renewable energy: some illustrative case studies2014Ingår i: Electric power systems research, ISSN 0378-7796, E-ISSN 1873-2046, Vol. 114, s. 39-48Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This paper presents the use of curtailment to allow more wind or solar power to be connected to a distribution network when overcurrent or overvoltage set a limit. Four case studies, all based on measurements, are presented. In all cases the hosting capacity method is used to quantify the gain in produced energy for increased levels of distributed renewable energy resources. A distinction is made between “hard curtailment” where all production is disconnected when overcurrent and overvoltage limits are exceeded and “soft curtailment” where the amount of production to be disconnected is minimized. It is shown that the type of curtailment method used has a large impact on the amount of delivered energy to the grid. The paper further discusses details of the curtailment algorithm, alternatives to curtailment, the communication needs and risks associated with the use of curtailment

  • 322. Etherden, Nicholas
    et al.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Project: SmartGrid Energilager2012Övrigt (Övrig (populärvetenskap, debatt, mm))
    Abstract [sv]

    Lösningar för optimerad reglering i realtid av distribuerad förnybar elproduktion, energilagring, samt styrbar last.

  • 323.
    Etherden, Nicholas
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    The use of battery storage for increasing the hosting capacity of the grid for renewable electricity production2014Konferensbidrag (Refereegranskat)
    Abstract [en]

    This paper defines a step-by-step systematic decision making process to define operant conditions and applications for which battery storage is an option for electrical power grids. The set of rules is based on a number of research studies performed by the authors focusing mainly on sub-transmission grids. Battery storage is expensive so the focus in this paper is on comparing storage with other ways of achieving the same increase in the hosting capacity (HC) of grid. The approach is to find niche applications for which battery storage has unique advantages i.e. it provides a unique alternative for grid operator planning, which is unachievable in other ways. The first step is to assess the grid’s capacity to host new loads or production. This constitutes a baseline for evaluation of improvements from storage. The next step is to define applications for battery energy storage. Integrating new loads/production without increasing the hosting capacity may result in reduced performance and ultimately loss of production or consumption. The cost and severity of exceeding the hosting capacity will also affect the type of solution required. After this define the conventional planning solutions that would be adopted without storage option available. Such measures may include upgrading of transformer or construction of new power line. Curtailment, tariff based incentives or contracted load shedding as well as techniques like dynamic line rating can also be included in the comparison at this stage. Based on assessments of these alternatives it is possible to compare increase in hosting capacity with and without storage as well as comparing gains with storage to what can be achieved with conventional grid planning options or other novel methods. It is also important to investigate the regulatory framework and constraints regarding ownership and operation of a battery energy storage. Should the grid operator own the battery storage? Or should the task be outsourced on a service contract or the service purchased in the market place? Storage capacity may only be utilized during certain periods. Can all or part of the storage capacity or the power electronic inverters perform additional functions and increase the return on investment for the installation? Regulatory aspects regarding the possibilities for different actors to pursue such additional income streams should be included in the assessment to correctly determine the return of investment of battery storage.The final step should include control algorithm development, tested in a flexible but realistic environment and should establish whether the system actually delivers the predicted outcomes when exposed to real-time data. This may require building a pilot installation as a research and development activity before commercial deployment.

  • 324.
    Etherden, Nicholas
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Ackeby, Susanne
    STRI AB.
    Lennerhag, Oscar
    STRI AB.
    The transparent hosting-capacity approach – overview, applications and developments2015Konferensbidrag (Refereegranskat)
    Abstract [en]

    This paper summarizes the hosting capacity approach and gives some recent developments: including uncertainty in location and size of production units; curtailment to connect more production than according to the initial hosting capacity. For both developments it is shown that the transparency of the approach still holds but also that the results may be strongly location dependent. It is however also shown that the hosting-capacity approach can be used to obtain rough estimations, rules-of-thumbs, and to make a first assessment in case more detailed studies are not possible for example because insufficient data is available.

  • 325.
    Etherden, Nicholas
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Lundkvist, J.
    Quantification of ancillary services from a virtual power plant in an existing subtransmision network2013Ingår i: Innovative Smart Grid Technologies Europe (ISGT EUROPE): 2013 4th IEEE/PES, Piscataway, NJ: IEEE Communications Society, 2013, s. 1-5Konferensbidrag (Refereegranskat)
    Abstract [en]

    This paper presents the results of a feasibility study of a virtual power plant (VPP) in central Sweden designed to provide ancillary services to a 50-kV distribution network. The VPP consists of a wind park, hydro plant and reservoir as well as solar PVs and battery energy storage. The 50-kV subtransmission network was modeled in order to evaluate the ancillary services that could be provided by coordinating existing distributed energy resources in the network. Simulations were performed using measured hourly variations in production and consumption at all network nodes. The studied ancillary services include both reactive and active power control. Contribution from the VPP is evaluated for balancing, to enable a producer to meet spot markets bids and avoid purchases of balancing power minimize peak load in order to reduce subscribed power and tariff to the regional 130-kV network decrease network losses the contribution from reactive power control using the power converters to reduce the reactive power flow to the overlying network. Quantification of the economic gains from each operation case is provided.

  • 326. Etherden, Nicholas
    et al.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Lundmark, Martin
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Project: Test bed – Energy supply for innovative mining from an environmental and energy perspective2014Övrigt (Övrig (populärvetenskap, debatt, mm))
  • 327.
    Etherden, Nicholas
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Lundmark, Martin
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Fernandez, Josep Maria
    CINERGIA. Barcelona.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Converter induced resonances in microgrids due to high harmonic distortion2014Ingår i: The Renewable Energies and Power Quality Journal (RE&PQJ), ISSN 2172-038X, E-ISSN 2172-038X, nr 12, artikel-id 317Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This paper describes the resonance introduced by adverse interaction of electronic converters. With the presence of multiple power-electronic converters, situations can occur where the harmonics are amplified due to the interaction between converters. An observation of undamped oscillation leading to instability in a microgrid is described. The term “converter induced resonances” is proposed to describe this phenomenon. The amount of distributed generation, active loads, FACTS and battery energy storage systems are expected to increase in future Smart Grids. All these resources will be interfaced with electronic converters. The potential impact of converter induced resonances in such grids is described. A coordinated design of the control systems of all converters is in practice not feasible. Each device will be independently tested to fulfil grid codes and have its own converter control implemented that can include functionality to modify voltage and /or current waveform.

  • 328.
    Etherden, Nicholas
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Tiesmäki, Ville
    FINGRID Oyj.
    Kimsten, Gert
    Svenska Kraftnät.
    A practical approach to verification and maintenance procedures for IEC 61850 substations2010Konferensbidrag (Refereegranskat)
    Abstract [en]

    IEC 61850 standard defines a large smorgasbord of different information models that can be used for safe commissioning and maintenance testing. These functionalities potentially allow for safe testing with the substation still in operation.Over the past two years the Finnish and Swedish TSOs have worked together with an independent test institute and consultancy company on a series of projects to explore the possibilities with IEC 61850 and to develop new commissioning and maintenance test procedures adapted to IEC 61850 systems. The first part of the project aimed to investigate procedures that could be used for site acceptance and maintenance testing. Based on available functionality in the standard an approach was envisioned for commissioning and maintenance. In practise few of the available test, simulation and blocking indications have been consistently implemented in the first generation of IEC 61850 devices. It was therefore necessary to move to a more interoperable (but not standardised) approach described in this paper.With the 2nd edition of the IEC 61850 standard there is a basis for more efficient and standardized testing methods. The finding from the project is that only a subset of the available possibilities for testing in the IEC 61850 standard are normally implemented. More consistent implementation and use of the test related functionality is required. To obtain this, utility and system integrator engineers need to get deeper involved in the definition, implementation, interpretation and use of the various test related information models and enter into active dialogue with the manufacturers of IEDs and test equipment.

  • 329.
    Etherden, Nicholas
    et al.
    STRI AB.
    Vyatkin, Valeriy
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Virtual Power Plant for Grid Services using IEC 618502016Ingår i: IEEE Transactions on Industrial Informatics, ISSN 1551-3203, E-ISSN 1941-0050, Vol. 12, nr 1, s. 437-447Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This paper assesses the communication, information and functional requirements of Virtual Power Plants (VPPs). A conceptual formulation of the interoperability requirements is presented as well as a comparative study of their fulfillment by state-of-the-art communication techniques. VPP requirements are then mapped against services and information models of IEC 61850 and CIM power utility automation standards. Proposals are given for extensions of the IEC 61850 standard to enhance the interaction between VPP controller and the distributed energy resources. Finally the methodology and concepts are applied to a specific VPP consisting of hydro and wind plants, solar PV and storage facilities. Several applications to provide grid services from the proposed VPP in an existing 50 kV grid are covered. The implementation of the VPP communication and control architecture in the SCADA of demonstration plant is also presented.

  • 330.
    Etherden, Nicholas
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Weingarten, L
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Physical-hybrid simulation for in-situ evaluation of energy storage system2012Ingår i: 3rd IEEE PES Innovative Smart Grid Technologies Europe, ISGT Europe 2012: Berlin;14 October 2012 through17 October 2012, Piscataway, NJ: IEEE Communications Society, 2012Konferensbidrag (Refereegranskat)
    Abstract [en]

    This paper presents a method for testing of a grid-size battery energy storage system and its interaction with the grid. The method uses a real installation with relatively small storage capacity which is combined with a simulation model of the grid. The storage is cycled based on measurements from the potential grid location and desired application. A scaling factor is used to relate the physical installation capacity and power ratings with the grid-size storage in the simulation model. Such a hybrid method allows evaluating grid-size storage installations without disturbing the grid. The physical behavior of the battery and control algorithm can be evaluated under realistic conditions without the need to construct a full grid-size storage installation. An experiment is described in this paper were the method is applied to an actual grid and battery storage installation

  • 331.
    Etherden, Nicholas
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Öhlen, Carl
    STRI AB.
    IEC 61850 – for much more than substations2010Ingår i: Revue E, ISSN 1377-7254, Vol. 126, nr 4-2010, s. 24-24Artikel i tidskrift (Övrig (populärvetenskap, debatt, mm))
    Abstract [en]

    IEC61850 is a standardized concept for information handling and communication for power utility automation. It is NOT just another protocol. IEC 61850 is today being expanded to apply to many domains beyond the original scope of the substation. Figure 1 illustrates the Expansion of IEC 61850 world to both control centre communication and modelling of communication with renewable energy resources.

  • 332.
    Fagerström, Jonathan
    et al.
    Umeå universitet.
    Näzelius, Ida-Linn
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Dan, Boström
    Umeå universitet.
    Öhman, Marcus
    Boman, Christoffer
    Umeå universitet.
    Reduction of fine particle- and deposit forming alkali by co-combustion of peat with wheat straw and forest residues2010Ingår i: Proceedings of the International Conference on Impact of Fuel Quality on Power production and the Environment., 2010Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

    Combustion of ash rich biomass fuels like forest residues and wheat straw often cause severe fouling/deposits and high emissions of PM1, mainly related to alkali transformation. Due to technical and air pollution aspects, primary process/fuel related measures for reduction of volatilized alkali could therefore be of importance. Peat has been used extensively in e g Sweden and Finland since the early 80th due to its positive ash chemical effects. Earlier research with co-combustion of peat and biomass has mostly been focused on fluidized bed boilers and aspects of bed agglomeration and deposits/corrosion. It has also been shown that the content and form of ash forming elements in different peats can vary significantly. The objective with this work was to determine the potential reduction of fine particle- and deposit forming alkali during co-combustion of forest residue and wheat straw with four different peat types in a small scale (15 kW) grate fired pellet boiler. The results showed that significant reduction of fine particle- and deposit forming alkali is possible, either simply by "dilution" of K content (e.g for wheat straw) or by "capturing" of K to bottom ash/slag (e.g. for forest residues), most probably caused by reaction of K vapour from the biomass with reactive Si or clay minerals from the peat. The alkali reduction potential for different biomass fuels and peat mixtures is dicussed in relation to the slagging tendencies and general ash transformation processes

  • 333.
    Fagerström, Jonathan
    et al.
    Umeå University. Department of Applied Physics and Electronics.
    Näzelius, Ida-Linn
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Gilbe, Carl
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Boström, Dan
    Umeå University. Department of Applied Physics and Electronics.
    Öhman, Marcus
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Boman, Christoffer
    Umeå University. Department of Applied Physics and Electronics.
    Influence of peat ash composition on particle emissions and slag formation in biomass grate co-combustion2014Ingår i: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 28, nr 5, s. 3403-3411Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Co-combustion by fuel blending of peat and biomass has shown positive effects on operational problems. However, peat ash compositions vary considerably, and this has been shown to affect the potential for operational problems in different fuel-blending situations. The present work used three different peat types with the objective to elucidate how the variation in peat ash composition influences both particle emissions and slag formation during co-combustion with three different biomasses in a small-scale pellet boiler. Estimations of potassium release and slag formation were performed and discussed in relation to fuel composition in the (K2O + Na2O)–(CaO + MgO)–(SiO2) system. All tested peat types reduced the fine particle emissions by capturing potassium into the bottom ash as one or several of the following forms: slag, sulfates, chlorides, and alumina silicates. However, there were considerable differences between the peat types, presumably depending upon both their content and mineral composition of silicon, calcium, aluminum, and sulfur. Some general important and beneficial properties of peat type in co-combustion situations with biomass are defined here, but the specific blending proportion of peat should be decided on an individual basis for each scenario based on the relative contents in the fuel mixture of the most relevant ash-forming elements.

  • 334.
    Fagerström, Jonathan
    et al.
    Thermochemical Energy Conversion Laboratory, Department of Applied Physics and Electronics, Umeå University.
    Rebbling, Anders
    Thermochemical Energy Conversion Laboratory, Department of Applied Physics and Electronics, Umeå University.
    Olwa, Joseph
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Steinvall, Erik
    Thermochemical Energy Conversion Laboratory, Department of Applied Physics and Electronics, Umeå University.
    Boström, Dan
    Thermochemical Energy Conversion Laboratory, Department of Applied Physics and Electronics, Umeå University.
    Öhman, Marcus
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Boman, Christoffer
    Thermochemical Energy Conversion Laboratory, Department of Applied Physics and Electronics, Umeå University.
    Control Strategies for Reduction of Alkali Release during Grate Combustion of Biomass: Influence of Process Parameters and Fuel Additives in a 40 kW Reactor2014Konferensbidrag (Refereegranskat)
  • 335. Faiz, J
    et al.
    Lotfi-fard, S.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Wavelet based Mann and Morrison algorithm for improvement of three-phase unbalanced voltage dips characterization2007Ingår i: IET Generation, Transmission & Distribution, ISSN 1751-8687, E-ISSN 1751-8695, Vol. 1, nr 4, s. 640-646Artikel i tidskrift (Refereegranskat)
  • 336.
    Falk, Joel
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Effect of fuel composition and combustion conditions on phosphorus behavior during combustion of biomass2018Licentiatavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    Due to concerns for climate change and future supply of phosphorus fertilizer within agriculture, there has been an increased interest in the combustion of phosphorus containing waste residues and opportunity biomass fuels. Previous research has shown that during combustion, phosphorus has large impact on ash transformation reactions and may decrease or increase ash-related problems such as slag formation and bed agglomeration. This is a serious concern if new types of biomass are to be added for heat and power production. Additionally, plant studies and leaching tests of P-rich biomass ash indicate that the plant availability of phosphorus varies greatly with its association in the ash. As such, the ash transformation behavior of phosphorus is of great importance for the success of such ventures. While several studies have been made on the behavior of phosphorus during combustion, no comprehensive study has been made evaluating the effect of fuel composition and combustion conditions.

    In this work, the behavior of phosphorus was determined for a wide range of fuels and combustion conditions. More specifically, the objective was to determine (i) the effect of fuel ash composition and combustion technologies on the fate of phosphorus during combustion, (ii) investigate potential difference in the behavior of phosphorus during combustion of sewage sludge and plant based biomassand (iii)the effect of phosphorus on slag formation and bed agglomeration for the co-combustion of a wide range of plant based biomasses.

    The investigation was carried out by comparing experimental data gathered from the combustion of 26different biomass fuelsor fuel blends in a bench scale bubbling fluidized bed (5 kW, 18 experiments), an underfed pellet burner (20kW, 10 experiments) and a swirling powder burner (150 kW, 7 experiments). This included chemical characterization of bed ash, bottom ash and fly ash fractions by X-ray diffraction (XRD), scanning electron microscopy coupled with energy dispersive spectroscopy (SEM-EDS) in addition to qualitative measures of slagging-and bed agglomeration tendencies.

    It was found that phosphorus, irrespective of combustion technology and fuel composition, was mainly found in bed-, and bottom ash fractions and/or coarse fly ash fractions (>1μm). Based on the crystalline phase composition of the phosphates found in bed-, bottom-and coarse fly ash samples, phosphate speciation was correlated to the molar ratio between P, Ca and Mg for all three combustion technologies. Based on these results, it would be possible to control the behavior of phosphorus during combustion and the plant availability of phosphates in biomassash by designing fuel blends based on their fuel ash composition.

    In fluidized bed combustion, it was found that for similar combustion conditions and fuel ash compositions (with respect to K, Ca and P), the speciation of phosphorus in coarse ash fractions was significantly different from experiments with plant based biomass compared to sewage sludge. Unlike ash from plant based biomass, the crystalline phase composition of ash from sewage sludge did not change with the relative concentration of K, Ca andP in the fuel. The results suggest that the reaction pathway of phosphorus during combustion of sewage sludge is different to plant based biomass due to difference in the association of phosphorus in the fuel.

    The effect of phosphorus on slag formation and bed agglomeration in biomass combustion was mainly related to the relative fuel ash concentration of K, Ca, Mg, Si and P. In fluidized bed combustion, P contributes to the formation of agglomerates through the melt induced mechanism, through complex interaction with K, Ca, Mg and Si. Similarly, in fixed bed combustion the composition of slag indicatedthatslag formation involves the formation of P and Si rich ash melt with a varying content of K, Ca and Mg. In both cases, the severity of problems was related to the melting behavior of the (CaO,MgO)-K2O-(SiO2,P2O5) multicomponent system.

    Publikationen är tillgänglig i fulltext från 2020-06-01 00:00
  • 337.
    Fallde, Magdalena
    et al.
    Department of Thematic Studies, Technology and Social Change, Linköping University.
    Torén, Johan
    RISE Research Institutes of Sweden.
    Wetterlund, Elisabeth
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Energy System Models as a Means of Visualising Barriers and Drivers of Forest-Based Biofuels: An Interview Study of Developers and Potential Users2017Ingår i: Sustainability, ISSN 2071-1050, E-ISSN 2071-1050, Vol. 9, nr 10, artikel-id 1792Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Forest-derived biofuels have been on the agenda for several decades. Despite extensive research and development efforts, forest biofuel concepts have nevertheless not yet been realized on any significant scale. The discrepancy between the expectations from the research community and the lack of momentum regarding biofuel production raises the question of if and how research results can be used to achieve such goals. Here, we report results from an interview study with the aim of evaluating how energy system models can be used to illustrate barriers and drivers for forest biofuels, with focus on Swedish conditions, using the BeWhere model as case. The study is framed as an example of expertise, and problematizes how energy system models are interpreted among expected users. While the interviews revealed some general scepticism regarding models, and what kinds of questions they can answer, the belief was also expressed that increased complexity might be an advantage in terms of being able to accommodate more barriers against forest biofuels. The study illustrates the complexity of this policy area, where an energy system model can answer some, but never all, ‘what if…?’ questions. The results reveal a need for reformation in energy system modelling in order to more explicitly make society the subject of the work, and also illustrate that the belief in expertise as a tool for consensus-building in decision-making should be questioned.

  • 338.
    Fan, Tengteng
    et al.
    College of Chemistry and Chemical Engineering, State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing University of Technology.
    Xie, Wenlong
    College of Chemistry and Chemical Engineering, State Key Laboratory of Materials-College of Chemistry and Chemical Engineering, Nanjing University of Technology.
    Ji, Xiaoyan
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Liu, Cheng
    College of Chemistry and Chemical Engineering, State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing University of Technology.
    Feng, Xie
    College of Chemistry and Chemical Engineering, State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing University of Technology.
    Lu, Xiaohua
    College of Chemistry and Chemical Engineering, State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing University of Technology.
    CO2/N2 separation using supported ionic liquid membranes with green and cost-effective [Choline][Pro]/PEG200 mixtures2016Ingår i: Chinese Journal of Chemical Engineering, ISSN 1004-9541, E-ISSN 2210-321X, Vol. 24, nr 11, s. 1513-1521Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The high price and toxicity of ionic liquids (ILs) have limited the design and application of supported ionic liquid membranes (SILMs) for CO2 separation in both academic and industrial fields. In this work, [Choline][Pro]/polyethylene glycol 200 (PEG200) mixtures were selected to prepare novel SILMs because of their green and cost-effective characterization, and the CO2/N2 separation with the prepared SILMs was investigated experimentally at temperatures from 308.15 to 343.15 K. The temperature effect on the permeability, solubility and diffusivity of CO2 was modeled with the Arrhenius equation. A competitive performance of the prepared SILMs was observed with high CO2 permeability ranged in 343.3-1798.6 barrer and high CO2/N2 selectivity from 7.9 to 34.8. It was also found that the CO2 permeability increased 3 times by decreasing the viscosity of liquids from 370 to 38 mPa·s. In addition, the inherent mechanism behind the significant permeability enhancement was revealed based on the diffusion-reaction theory, i.e. with the addition of PEG200, the overall resistance was substantially decreased and the SILMs process was switched from diffusion-control to reaction-control. 

  • 339.
    Faust, Robin
    et al.
    Department of Chemistry and Chemical Engineering, Chalmers University of Technology, Gothenburg, Sweden.
    Hannl, Thomas Karl
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Berdugo Vilches, Teresa
    Department of Chemistry and Chemical Engineering, Chalmers University of Technology, Gothenburg, Sweden.
    Kuba, Matthias
    Bioenergy2020+ GmbH, Güssing, Austria.
    Öhman, Marcus
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Seemann, Martin
    Department of Space, Earth and Environment, Chalmers University of Technology, Gothenburg, Sweden.
    Knutsson, Pavleta
    Department of Space, Earth and Environment, Chalmers University of Technology, Gothenburg, Sweden.
    Layer Formation on Feldspar Bed Particles during Indirect Gasification of Wood. 1. K-Feldspar2019Ingår i: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 33, nr 8, s. 7321-7332Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The choice of bed material for biomass gasification plays a crucial role for the overall efficiency of the process. Olivine is the material conventionally used for biomass gasification due to the observed activity of olivine toward cracking of unwanted tars. Despite its catalytic activity, olivine contains high levels of chromium, which complicates the deposition of used bed material. Feldspar has shown the same activity as olivine when used as a bed material in biomass gasification. As opposed to olivine, feldspar does not contain environmentally hazardous compounds, which makes it a preferred alternative for further applications. The interaction of bed material and ash heavily influences the properties of the bed material. In the present study interactions between feldspar and main ash compounds of woody biomass in an indirect gasification system were investigated. Bed material samples were collected at different time intervals and analyzed with SEM-EDS and XRD. The obtained analysis results were then compared to thermodynamic models. The performed study was divided in two parts: in part 1 (the present paper), K-rich feldspar was investigated, whereas Na-rich feldspar is presented in part 2 of the study (DOI: 10.1021/acs.energyfuels.9b01291). From the material analysis performed, it can be seen that, as a result of the bed materials’ interactions with the formed ash compounds, the latter were first deposited on the surface of the K-feldspar particles and later resulted in the formation of Ca- and Mg-rich layers. The Ca enriched in the layers further reacted with the feldspar, which led to its diffusion into the particles and the formation of CaSiO3 and KAlSiO4. Contrary to Ca, Mg did not react with the feldspar and remained on the surface of the particles, where it was found as Mg- or Ca-Mg-silicates. As a result of the described interactions, layer separation was noted after 51 h with an outer Mg-rich layer and an inner Ca-rich layer. Due to the development of the Ca- and Mg-rich layers and the bed material–ash interactions, crack formation was observed on the particles’ surfaces.

  • 340.
    Ferreira, Danton D.
    et al.
    Federal University of Lavras.
    Seixas, Jose M. de
    Federal University of Rio de Janeiro, COPPE/Poli.
    Cerqueira, Augusto S.
    Department of Electrical Circuits, Federal University of Juiz de Fora, Campus Universitário.
    Duque, Carlos A.
    Department of Electrical Circuits, Federal University of Juiz de Fora, Campus Universitário.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Ribeiro, Paulo F.
    Federal University of Itajubá.
    A new power quality deviation index based on principal curves2015Ingår i: Electric power systems research, ISSN 0378-7796, E-ISSN 1873-2046, Vol. 125, s. 8-14, artikel-id 4289Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In this paper, a new power quality deviation index based on principal curves is proposed. The index provides a quantitative measure, which gives an idea of how much the monitored electrical signal has deviated from the nominal one. Differently of existing indices, the proposed index is a general index, i.e., it can be used for any type of disturbance in the monitored signal. In addition, the proposed index is used to perform a direct approach for detecting disturbances in power signals. This approach is able to detect the beginning and localize the disturbance by analyzing non-overlapping signal windows of one cycle of the fundamental component, leading to a simple method in terms of computational complexity

  • 341.
    Ferreira, Danton D.
    et al.
    Federal University of Lavras, Engineering Department, Federal University of Lavras.
    Seixas, Jose M. de
    Federal University of Rio de Janeiro, COPPE/Poli.
    Cerqueira, Augusto S.
    Department of Electrical Circuits, Federal University of Juiz de Fora, Campus Universitário.
    Duque, Carlos A.
    Federal University of Juiz de Fora, Minas Gerais, Department of Electrical Circuits, Federal University of Juiz de Fora, Campus Universitário.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Ribeiro, Paulo F.
    Federal University of Itajubá, Department of Electrical Engineering, Federal University of Itajubá.
    Extracting the transient events from power system signals by independent component analysis2016Ingår i: International Studies in Religion and Society, ISSN 1530-1311, E-ISSN 2050-7038, Vol. 26, nr 4, s. 884-900Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This paper presents a method for extracting transient events from the power system signal based on independent component analysis. The extraction of transients is important to diagnose the system in terms of power quality, because the computation of power quality indices from the extracted events is more efficient and easier to be carried out. Furthermore, the proposed method can be applied as a preprocessing tool for transient characterization in disturbance detection, classification, and identification systems. Both qualitative and quantitative analyses demonstrate the efficiency and the advantages of the proposed method in comparison with other approaches commonly used for the same purpose.

  • 342.
    Filho, J.M.C.
    et al.
    Itajuba Federal University, Brazil.
    Leborgne, R.C.
    Federal University of Rio Grande do Sul (UFRGS), Porto Alegre.
    Abreu, J.P.G de
    Itajuba Federal University, Brazil.
    Novaes, E.G.C
    Petrobras, Rio de Janeiro.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Validation of voltage sag simulation tools: ATP and short-circuit calculation versus field measurements2008Ingår i: IEEE Transactions on Power Delivery, ISSN 0885-8977, E-ISSN 1937-4208, Vol. 23, nr 3, s. 1472-1480Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Two methods to calculate voltage sags are validated against actual measurements. One of the methods is a short-circuit calculation program resulting directly in sag magnitude during the fault. The other is an electromagnetic transient program resulting in voltage waveform as a function of time. Individual sag characteristics and system performance obtained by deterministic simulation and measurement are compared. The influence of the random variables (prefault voltage, fault location and fault impedance) is investigated.

  • 343. Filho, L.M.C
    et al.
    Leborgne, R.C
    Silveira, P.M da
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Voltage sag index calculation: comparison between time-domain simulation and short-circuit calculation2008Ingår i: Electric power systems research, ISSN 0378-7796, E-ISSN 1873-2046, Vol. 78, nr 4, s. 676-682Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This paper describes a case study where voltage sags indices are estimated using Monte Carlo approach combined with ATP (Alternative Transient Program) and short-circuit calculation program. Voltage sag magnitude and frequency are used to evaluate the correlation between both programs. The results indicate that time-domain simulation and short-circuit calculation gives similar voltage sag indices. Considering the high correlation between the results, short-circuit calculation programs are preferable over the time-domain simulation tools as the modelling for time-domain simulation is more complex, time consuming, and rarely covers the whole network.

  • 344.
    Fischer, Robert
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Elfgren, Erik
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Toffolo, Andrea
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Energy Supply Potentials in the Northern Counties of Finland, Norway and Sweden towards Sustainable Nordic Electricity and Heating Sectors: A Review2018Ingår i: Energies, ISSN 1996-1073, E-ISSN 1996-1073, Vol. 11, nr 4, artikel-id 751Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The lands in the northernmost corner of Europe present contradictory aspects in their social and economic development. Urban settlements are relatively few and small-sized, but rich natural resources (minerals, forests, rivers) attract energy-intensive industries. Energy demand is increasing as a result of new investments in mining and industries, while reliable energy supply is threatened by the planned phase out of Swedish nuclear power, the growth of intermittent power supplies and the need to reduce fossil fuel consumption, especially in the Finnish and Norwegian energy sectors. Given these challenges, this paper investigates the potentials of so far unexploited energy resources in the northern counties of Finland, Norway and Sweden by comparing and critically analyzing data from statistic databases, governmental reports, official websites, research projects and academic publications. The criteria for the technical and economic definition of potentials are discussed separately for each resource. It is concluded that, despite the factors that reduce the theoretical potentials, significant sustainable techno-economic potentials exist for most of the resources, providing important insights about the possible strategies to contribute to a positive socio-economic development in the considered regions.

  • 345.
    Flores-Arias, J.M.
    et al.
    University of Cordoba.
    Bellido-Outeirino, F.J.
    University of Cordoba.
    Moreno-Munoz, Antonio
    University of Cordoba, Department of Computer Architecture, Electronics and Electronic Technology, University of Cordoba.
    Linan-Reyes, M.
    University of Cordoba.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Validation of a Embeddable Volt age Phasor Magnitude Meter for Household and Commercial Environments2015Ingår i: IEEE International Conference on Consumer Electronics: (ICCE), 2015 9 - 12 Jan. 2015, Las Vegas, NV, USA, Piscataway, NJ: IEEE Communications Society, 2015, s. 616-617Konferensbidrag (Refereegranskat)
    Abstract [en]

    The most popular, fast and reliable voltage event and power quality disturbance detection algorithm in domestic and commercial appliances is the measurement of the RMS voltage value.

  • 346.
    Fomari, Frederica
    et al.
    University of Genova, Department of Electrical Engineering.
    Procopio, Renato
    University of Genova, Department of Electrical Engineering.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    SSC compensation capability of unbalanced voltage sags2005Ingår i: IEEE Transactions on Power Delivery, ISSN 0885-8977, E-ISSN 1937-4208, Vol. 20, nr 3, s. 2030-2037Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In this paper, the capacity of a static series compensator (SSC) to compensate for voltage sags is discussed, and a complete analysis of the effects of unbalanced Sags on the SSC compensation capability is carried out. Expressions are obtained for the missing voltage during unbalanced voltage sags. These expressions are used to estimate how often a voltage sag occurs where the missing voltage exceeds the injection capability of the SSC. The method is applied to a typical Italian network configuration

  • 347.
    Forouzan, Farnoosh
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
    Gunasekaran, Suresh
    Department for Materials Science, Functional Materials, Saarland University.
    Hedayati, Ali
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Vuorinen, Esa
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
    Mücklich, Frank
    Department for Materials Science, Functional Materials, Saarland University.
    Microstructure analysis and mechanical properties of Low alloy High strength Quenched and Partitioned Steel2016Ingår i: MSMF 2016: Materials Structure & Micromechanics of Fracture, 2016Konferensbidrag (Refereegranskat)
  • 348.
    Forouzan, Farnoosh
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
    Gunasekaran, Suresh
    Hedayati, Ali
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Vuorinen, Esa
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
    Mücklich, Frank
    Department for Materials Science, Functional Materials, Saarland University, D-66041 Saarbrücken, Germany.
    Microstructure analysis and mechanical properties of Low alloy High strength Quenched and Partitioned Steel2017Ingår i: Solid State Phenomena, ISSN 1012-0394, E-ISSN 1662-9779, Vol. 258, s. 574-578Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Gleeble study of the quenching and partitioning (Q&P) process has been performed onDomex 960 steel (Fe, 0.08 %C, 1.79 %Mn, 0.23 %Si, 0.184 %Ti, and 0.038 %Al). The effect ofdifferent Q&P conditions on microstructure and mechanical properties were investigated. The aimof the process is to produce a fine grained microstructure for better ductility and controlled amountsof different micro-constituents to increase the strength and toughness simultaneously. Threedifferent quenching temperatures, three partitioning temperatures and three partitioning times havebeen selected to process the 27 specimens by Gleeble® 1500. The specimens were characterized bymeans of OM, SEM, XRD, hardness and impact tests. It was found that, fine lath martensite withretained austenite is achievable without high amount of Si or Al in the composition although lack ofthese elements may cause the formation of carbides and decrease the available amount of carbon forpartitioning into the austenite. The hardness increases as the quenching temperature is decreased,however, at highest partitioning temperature (640◦C) the hardness increases sharply due to extensiveprecipitate formation.

  • 349.
    Forsberg, Jonas
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Krook-Riekkola, Anna
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Supporting Cities’ Emission Mitigation Strategies: Modelling Urban Transports in a TIMES Energy System Modelling Framework2017Ingår i: Urban Transport XXIII / [ed] S. Ricci;C. A. Brebbia, Southampton: WIT Press, 2017, Vol. 176, s. 15-25Konferensbidrag (Refereegranskat)
    Abstract [en]

    The transport sector is a significant emitter of greenhouse gases (GHGs) and air pollutants in urban areas. How the transport sector evolve during the coming decades will have significant impact on the possibilities to meet tough climate and environmental targets. This makes transportation an important part of cities’ Sustainable Energy and Climate Action Plans. Still, transportation is somewhat overlooked in many city-level analyses. Energy system optimisation models, like the TIMES modelling framework, are useful tools in identifying energy pathways to reach ambitious energy savings and emission mitigation targets. Based on the identification of urban transport-energy system characteristics, the needs of local governments, and insights from traditional transport models, we propose a partly new representation of the transport sector within a TIMES-City modelling framework, adapting it to the urban transport-energy setting to improve model realism and power of insight. TIMES-City supports analysis of intracity and long-distance passenger and freight transportation, including only the city organisation or the entire administrative city area. Detailed techno-economic-environmental representation of all major existing and emerging modes, technologies a nd fuels p rovides basis for consistent long-term analyses.

  • 350. Fredriksson, C.
    et al.
    Degerman, B.
    Kjellström, Björn
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Effects of steam injection and stoichiometry on cyclone gasification of wood powder1996Ingår i: 1996 International Gas Turbine and Aeroengine Congress and Exhibition, American Society of Mechanical Engineers , 1996, Vol. 3 : Coal, Biomass and Alternative Fuels; Combustion and Fuels; Oil and GasKonferensbidrag (Refereegranskat)
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