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  • 1201.
    Xie, Wenlong
    et al.
    Department of Chemistry and Chemical Engineering, State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing Tech University, Nanjing.
    Ji, Xiaoyan
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Fan, Tengteng
    Department of Chemistry and Chemical Engineering, State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing Tech University, Nanjing.
    Feng, Xin
    State Key Laboratory of Materials-Oriented Chemical Engineering, College of Chemistry and Chemical Engineering, Nanjing University of Technology, Nanjing University of Chemical Technology, State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing University of Technology.
    Lu, Xiaohua
    State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing University of Technology, College of Chemistry and Chemical Engineering, Nanjing University of Technology.
    CO2 uptake behavior of supported tetraethylenepentamine sorbents2016Inngår i: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 30, nr 6, s. 5083-5091Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Supported tetraethylenepentamine (TEPA) sorbents have been proposed as an attractive alternative for postcombustion carbon capture. To promote the application of these sorbents, in this work, a systematic investigation of CO2 absorption behavior on five TEPA-immobilized sorbents was conducted, in which the effects of TEPA loading, supports, and temperatures on both CO2 absorption working capacity and kinetics were studied. Poly(methyl methacrylate) (PMMA)-TEPA is the best among the studied sorbents. The optimal temperature for PMMA-TEPA was 25 deg lower compared to other sorbents studied in this work, and the maximum CO2 capacity was 0.17 g/g-sorbent. This is the highest value reported to date for PMMA-TEPA sorbents, and one of the high values that have been reported for TEPA-immobilized sorbents. In addition, the working capacity of PMMA-TEPA after six cycles of regeneration was 0.16 g/g-sorbent (i.e., with only 6% decrease). Therefore, PMMA is promising to be used as supporting material for TEPA in CO2 capture. The kinetics analysis with both the Avrami’s fractional-order kinetic model and the mass-transfer model on the basis of nonequilibrium thermodynamics was further conducted and discussed. Besides, it was also found that the CO2 absorption kinetics and capacity were affected by both the pore structure and the surface chemistry of the support.

  • 1202.
    Xie, Wenlong
    et al.
    Department of Chemistry and Chemical Engineering, State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing Tech University, Nanjing.
    Ji, Xiaoyan
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Feng, Xin
    State Key Laboratory of Materials-Oriented Chemical Engineering, College of Chemistry and Chemical Engineering, Nanjing University of Technology, Nanjing University of Chemical Technology, State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing University of Technology, Department of Chemistry and Chemical Engineering, State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing Tech University, Nanjing.
    Lu, Xiaohua
    State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing University of Technology, College of Chemistry and Chemical Engineering, Nanjing University of Technology, Department of Chemistry and Chemical Engineering, State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing Tech University, Nanjing.
    Mass Transfer Rate Enhancement for CO2 Separation by Ionic Liquids: Effect of Film Thickness2016Inngår i: Industrial & Engineering Chemistry Research, ISSN 0888-5885, E-ISSN 1520-5045, Vol. 55, nr 1, s. 366-372Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Ionic liquids (ILs) are promising in CO2 separation, while the film thickness is particularly critical for gas transport in these viscous and expensive liquids. In this work, the influence of IL-film thickness on CO2 absorption/desorption of two different IL immobilized sorbents was investigated, in which the results from the thermogravimetric analyzer were further used to estimate the scale of IL-film thickness. It is found that the IL-film in nanoscale is a prerequisite for efficient CO2 absorption/desorption; the equilibrium time can be 10-times different, and the rate constant can be 100-times different for microscale and nanoscale IL-films. This is the first time to quantitatively reveal the influence of IL-film thickness and find out its scale for a significant rate enhancement in the CO2 absorption/desorption by IL immobilized sorbents

  • 1203.
    Xie, Wenlong
    et al.
    State Key Laboratory of Materials-Oriented Chemical Engineering, College of Chemistry and Chemical Engineering, Nanjing University of Technology.
    Ji, Xiaoyan
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Feng, Xin
    State Key Laboratory of Materials-Oriented Chemical Engineering, College of Chemistry and Chemical Engineering, Nanjing University of Technology.
    Lu, Xiaohua
    State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing University of Technology, College of Chemistry and Chemical Engineering, Nanjing University of Technology.
    Mass‐Transfer Rate Enhancement for CO2 Separation by Ionic Liquids: Theoretical Study on the Mechanism2015Inngår i: AIChE Journal, ISSN 0001-1541, E-ISSN 1547-5905, Vol. 61, nr 12, s. 4437-4444Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    To promote the development of ionic liquid (IL) immobilized sorbents and supported IL membranes (SILMs) for CO2 separation, the kinetics of CO2 absorption/desorption in IL immobilized sorbents was studied using a novel method based on nonequilibrium thermodynamics. It shows that the apparent chemical-potential-based mass-transfer coefficients of CO2 were in three regions with three-order difference in magnitude for the IL-film thicknesses in microscale, 100 nm-scale, and 10 nm-scale. Using a diffusion-reaction theory, it is found that by tailoring the IL-film thickness from microscale to nanoscale, the process was altered from diffusion-control to reaction-control, revealing the inherent mechanism for the dramatic rate enhancement. The extension to SILMs shows that the significant improvement of CO2 flux can be obtained theoretically for the membranes with nanoscale IL-films, which makes it feasible to implement CO2 separation by ILs with low investment cost

  • 1204.
    Xie, Yujiao
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    CO2 Separation with Ionic Liquids -Property, Gas solubility and Energy consumption2014Licentiatavhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Ionic liquids (ILs) have shown great potential to be used as liquid absorbents for CO2 capture because of its advantages, such as non-volatility, functionality, high CO2 solubility and lower energy requirements for regeneration. A significant amount of research has been carried out, but most of them are on the synthesis of novel ILs and the measurements of CO2 solubility in ILs. However, the application of IL-based technology for CO2 capture requires knowledge of gas solubility, the effect of other components on CO2 solubility, the thermo-physical properties, modeling as well as process simulation. Therefore, a tremendous gap exists between new technology development and implementation. The goal of this work is to perform a systematic study from experimental measurement, model development to process simulation in order to promote the development and application of IL-based technology for CO2 capture. In this work, the solubilities of CO2, CH4, H2, CO and N2 in choline chloride (ChCl)/urea (1:2 on a molar basis) were determined. The effect of water on the density, viscosity and CO2 solubility in ChCl/urea (1:2) were measured. The experimental gas solubility data was represented with the Non Random Two Liquid - Redlich Kwong (NRTL-RK) model. The results show that the addition of water significantly decreases the viscosity of ChCl/urea (1:2) while the effects on their density and CO2 solubility are much weaker. The excess molar volume and excess molar activation energy were calculated based on the experimental density and viscosity data. It was found that the intermolecular interaction between ChCl/urea and water is strong, and the hydrogen bond interaction is influenced by the temperature and water concentration. Meanwhile, the experimental data of CO2 solubility in imidazolium-based ILs at pressures below 10 MPa was surveyed and evaluated by NRTL-RK model. The CO2 absorption enthalpy and the energy consumption for a CO2 separation process using ILs by pressure swing and/or temperature swing were investigated. The results reveal that the temperature-dependent Henry’s constant is an important factor for energy consumption analysis in a pressure swing process, while the heat capacity of ILs plays a more important role in a temperature swing process.

  • 1205.
    Xie, Yujiao
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Björkmalm, Johanna
    SP Technical Research Institute of Sweden, Box 857, 501 15 Borås.
    Ma, Chunyan
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Willquist, Karin
    SP Technical Research Institute of Sweden, Box 857, 501 15 Borås.
    Yngvesson, Johan
    SP Technical Research Institute of Sweden, Box 857, 501 15 Borås.
    Wallberg, Ola
    Department of Chemical Engineering, Lund University.
    Ji, Xiaoyan
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Techno-economic evaluation of biogas upgrading using ionic liquids in comparison with industrially used technology in Scandinavian anaerobic digestion plants2018Inngår i: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 227, s. 742-750Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The process of biogas upgrading with ionic liquids, i.e. pure 1-butyl-3-methylimidazolium bis(trifluoro-methylsulfonyl)imide ([bmim][Tf2N]), aqueous choline chloride/urea (ChCl/Urea), and aqueous 1-allyl-3-methyl imidazole formate ([Amim][HCOO]), was simulated in Aspen Plus and compared with the conventional water scrubbing upgrading technique. The comparisons of the performances on the amount of recirculated solvents and energy usage show the following order: aqueous [Amim][HCOO]<aqueous ChCl/Urea<[bmim][Tf2N]<water. Six different co-digestion plants (anaerobic digestion, AD, plants) were surveyed to acquire data for comparison. The selected plants had different raw biogas production capacities and produced gas with differing methane content. The data confirmed the simulation results that the type of substrate and the configuration of AD process are two factors affecting energy usage, investment cost, as well as operation and maintenance costs for the subsequent biogas upgrading. In addition, the simulation indicated that the energy usage of the ionic liquid-based upgrading was lower than that of the conventional upgrading techniques in Scandinavian AD plants. The estimated cost including investment, operation and maintenance for the ionic liquid technology showed to be lower than that for the water scrubbing upgrading process.

  • 1206.
    Xie, Yujiao
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Dong, Haifeng
    Beijing Key Laboratory of Ionic Liquids Clean Process, State Key Laboratory of Multiphase Complex System, Institute of Process Engineering, Chinese Academy of Sciences.
    Zhang, Soujiang
    Beijing Key Laboratory of Ionic Liquids Clean Process, State Key Laboratory of Multiphase Complex System, Institute of Process Engineering, Chinese Academy of Sciences.
    Lu, Xuaihua
    Beijing Key Laboratory of Ionic Liquids Clean Process, State Key Laboratory of Multiphase Complex System, Institute of Process Engineering, Chinese Academy of Sciences.
    Ji, Xiaoyan
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Solubilities of CO2, CH4, H2, CO and N2 in choline chloride/urea2017Inngår i: Green Energy & Environment, ISSN 2468-0257, Vol. 1, nr 3, s. 195-200Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Solubilities of CO2, CH4, H2, CO and N2 in choline chloride/urea (ChCl/Urea) were investigated at temperatures ranging from 308.2 to 328.2 K and pressures ranging from 0.6 to 4.6 MPa. The results show that the solubilities of gases increase with increasing pressure and decreasing temperature. The solubility of CO2 is higher than that of CH4, H2, CO and N2, which indicates that ChCl/Urea may be used as a potential solvent for CO2 capture from the gas mixture. Solubility of CO2 in ChCl/Urea was fitted by Non-Random Two-Liquid and Redlich–Kwong (NRTL-RK) model, and solubility of CH4, H2, CO or N2 in ChCl/Urea was fitted by Henry's Law. The standard enthalpy, standard Gibbs energy and standard entropy of gases were calculated. Additionally, the CO2/CH4 selectivities in water, dry ChCl/Urea and aqueous ChCl/Urea were further discussed.

  • 1207.
    Xie, Yujiao
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Dong, Haifeng
    Beijing Key Laboratory of Ionic Liquids Clean Process, State Key Laboratory of Multiphase Complex System, Institute of Process Engineering, Chinese Academy of Sciences, Beijing.
    Zhang, Suojiang
    Beijing Key Laboratory of Ionic Liquids Clean Process, State Key Laboratory of Multiphase Complex System, Institute of Process Engineering, Chinese Academy of Sciences, Beijing.
    Lu, Xiaohua
    State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing University of Technology, College of Chemistry and Chemical Engineering, Nanjing University of Technology.
    Ji, Xiaoyan
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Effect of Water on the Density, Viscosity, and CO2 Solubility in Choline Chloride/Urea2014Inngår i: Journal of Chemical and Engineering Data, ISSN 0021-9568, E-ISSN 1520-5134, Vol. 59, nr 11, s. 3344-3352Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    To study the effect of water on the properties of choline chloride (ChCl)/urea mixtures (1:2 on a molar basis), the density and viscosity of ChCl/urea (1:2) with water were measured at temperatures from 298.15 K to 333.15 K at atmospheric pressure, the CO2 solubility in ChCl/urea (1:2) with water was determined at 308.2 K, 318.2 K, and 328.2 K and at pressures up to 4.5 MPa. The results show that the addition of water significantly decreases the viscosity of ChCl/urea (1:2), whereas the effects on their density and CO2 solubility are much weaker. The CO2 solubility in ChCl/urea (1:2) with water was represented with the Nonrandom-Two-Liquid Redlich–Kwong (NRTL-RK) model. The excess molar volume and excess molar activation energy were further determined. The CO2 absorption enthalpy was calculated and dominated by the CO2 dissolution enthalpy, and the magnitude of the CO2 dissolution enthalpy decreases with the increase of water content.

  • 1208.
    Xie, Yujiao
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Dong, Haifeng
    Beijing Key Laboratory of Ionic Liquids Clean Process, State Key Laboratory of Multiphase Complex System, Institute of Process Engineering, Chinese Academy of Sciences, Beijing.
    Zhang, Suojiang
    Beijing Key Laboratory of Ionic Liquids Clean Process, State Key Laboratory of Multiphase Complex System, Institute of Process Engineering, Chinese Academy of Sciences, Beijing.
    Lu, Xiaohua
    State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing University of Technology.
    Ji, Xiaoyan
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Thermophysical properties and gas solubilities in choline chloride/urea for CO2 separation2013Konferansepaper (Fagfellevurdert)
  • 1209.
    Xie, Yujiao
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Ji, Xiaoyan
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Feng, Xin
    Lu, Xiaohua
    Thermodynamic study for gases in ionic liquids at infinite dilution for CO2 capture/separation2012Konferansepaper (Fagfellevurdert)
  • 1210.
    Xie, Yujiao
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Ma, Chunyan
    State Key Laboratory of Materials-Oriented Chemical Engineering, College of Chemistry and Chemical Engineering, Nanjing University of Technology.
    Lu, Xiaohua
    Key Laboratory of Material and Chemical Engineering, Nanjing University of Technology.
    Ji, Xiaoyan
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Evaluation of imidazolium-based ionic liquids for biogas upgrading2016Inngår i: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 175, s. 69-81Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The conceptual processes for biogas upgrading using three imidazolium-based ionic liquids ([hmim][Tf2N], [bmim][Tf2N] and [bmim][PF6]) were simulated in Aspen Plus to study the effect of properties of ionic liquids (ILs) on the process performance. To conduct the process simulation, each IL was input into Aspen Plus as a pseudo component, their critical properties were estimated by group contribution method, and their thermo-physical properties were correlated from the available experimental data by semi-empirical equations. The gas solubility in ILs was modeled with the non-random two-liquid model and Redlich–Kwong equation of state. Among the studied ILs, the simulation results show that the amount of recirculated solvents and the total energy consumption for upgrading process using ILs follow: [bmim][Tf2N] < [bmim][PF6] < [hmim][Tf2N]. The effects of density and viscosity of ILs on pressure drop and diameter of the absorber as well as the effects of operational pressures and temperatures on the process efficiency were investigated. It is found that the energy consumption increases with increasing pressure and temperature in the absorber and decreases with increasing pressure in the first flash tank. The ILs-based technology was further compared with water scrubbing and aqueous choline chloride/urea scrubbing, and the comparison shows that the total energy consumptions follow: 50%ChCl/Urea-water < [bmim][Tf2N] scrubbing < water scrubbing

  • 1211.
    Xie, Yujiao
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Raut, Dilip G.
    Chemical-Biological Centre, Technical Chemistry, Department of Chemistry, Umeå University.
    Samikannu, Rakesh
    Chemical-Biological Centre, Technical Chemistry, Department of Chemistry, Umeå University.
    Mikkola, Jyri-Pekka
    Technical Chemistry, Department of Chemistry, Chemical-Biological Centre, Umeå University.
    Ji, Xiaoyan
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    A Thermodynamic Study of Aqueous 1-Allyl-3-Methylimidazolium Formate Ionic Liquid as a Tailored Sorbent for Carbon Dioxide Separation2017Inngår i: Energy Technology, ISSN 2194-4288, Vol. 5, nr 8, s. 1464-1471Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In this work, aqueous 1-allyl-3-methylimidazolium formate ([Amim][HCOO]) was studied as a potential sorbent for CO2 separation. The density and viscosity of aqueous [Amim][HCOO] were measured at temperatures ranging from 293.15 to 333.15 K at atmospheric pressure. The solubility of CO2 and CH4 in dry [Amim][HCOO] as well as the CO2 solubility in aqueous [Amim][HCOO] were measured at pressures up to 1.8 MPa and temperatures of 298.2, 313.2, and 333.2 K. The results showed that the density and viscosity of aqueous [Amim][HCOO] as well as the CO2 solubility in aqueous [Amim][HCOO] decreased upon increasing the water concentration and temperature. The viscosity was very sensitive to the water concentration. The experimental density and viscosity of aqueous [Amim][HCOO] were fitted to semiempirical equations, and the excess molar volume and viscosity deviations were calculated to investigate the interaction between the [Amim][HCOO] ionic liquid and water. The experimental vapor–liquid equilibrium was represented with the nonrandom two-liquid and Redlich–Kwong model. The model parameters can be further implemented into Aspen Plus software to conduct process simulations.

  • 1212.
    Xie, Yujiao
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Raut, Dilip
    Chemical-Biological Centre, Technical Chemistry, Department of Chemistry, Umeå University.
    Mikkola, Jyri-Pekka
    Process Chemistry Centre, Laboratory of Industrial, Chemistry and Reaction Engineering, Åbo Akademi University.
    Ji, Xiaoyan
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Thermodynamic study on CO2 separation with a novel ionic liquid2015Konferansepaper (Fagfellevurdert)
    Abstract [en]

    1-allyl-3-methylimidazolium formate ([Amim][HCOO]) exhibited higher solubility for various polysaccharides because of the strong hydrogen bond ability. In this work, the density and viscosity of [Amim][HCOO] were measured at different temperatures, the CO2 and CH4 solubilities in [Amim][HCOO] were determined at temperatures from 298.15 to 333.15 K and at pressures up to 2 MPa. The density and viscosity of [Amim][HCOO] were fitted by semi-empirical equations, and the experimental gas solubility was represented by thermodynamic model. The energy consumption for CO2 separation was calculated and compared with the conventional ILs.

  • 1213.
    Xie, Yujiao
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Zhang, Yingying
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Lu, Xiaohua
    State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing University of Technology, College of Chemistry and Chemical Engineering, Nanjing University of Technology.
    Ji, Xiaoyan
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Energy consumption analysis for CO2 separation using imidazolium-based ionic liquids2014Inngår i: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 136, s. 325-335Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    CO2 solubility in ionic liquids has been measured extensively in order to develop ionic liquid-based technology for CO2 separation. However, the energy consumption analysis has not been investigated well for such technology. In order to carry out the energy consumption analysis for CO2 separation using ionic liquids based on available experimental data, in this work, the experimental data of the CO2 solubility in imidazolium-based ionic liquids at pressures below 10 MPa was surveyed and evaluated by a semi-empirical thermodynamic model firstly. Based on the reliable experimental solubility data, the enthalpy of CO2 absorption was further calculated by the thermodynamic model. The results show that the CO2 absorption enthalpy in the studied ionic liquids is dominated by the enthalpy of CO2 dissolution and the contribution of excess enthalpy increases with increasing CO2 solubility in ionic liquids. The magnitude of the CO2 absorption enthalpy decreases with increasing chain length in cation and strongly depends on the anion of ionic liquids. Furthermore, the energy consumption for a CO2 separation process by pressure swing and/or temperature swing was investigated. For the pressure swing process, the Henry’s constant of CO2 in ionic liquids is an important factor for energy consumption analysis; If CO2 is absorbed at 298 K and 1 MPa and ionic liquid is regenerated by decreasing the pressure to 0.1 MPa at the same temperature, among the studied ionic liquids, [emim][EtSO4] is the solvent with the lowest energy consumption of 9.840 kJ/mol CO2. For the temperature swing process, the heat capacity of ionic liquids plays a more important role; If CO2 is absorbed at 298 K and desorbed at 323 K and 0.1 MPa, [emim][PF6] is the solvent with the lowest energy demand of 888.9 kJ/mol CO2. If the solvent is regenerated by releasing pressure and increasing temperature, both the Henry’s constant of CO2 in ionic liquids and the heat capacity of ionic liquids are important for analyzing the energy consumption; If CO2 is absorbed at 298 K and 1 MPa and ionic liquid is regenerated at 323 K and 0.1 MPa, [bmim][Tf2N] is the solvent with the lowest energy consumption of 57.71 kJ/mol CO2.

  • 1214.
    Xiong, Shaojun
    et al.
    Swedish University of Agricultural Sciences, Department of Forest Biomaterials and Technology.
    Bozaghian, Marjan
    Swedish University of Agricultural Sciences, Department of Forest Biomaterials and Technology.
    Lestander, Torbjörn A.
    Swedish University of Agricultural Sciences, Department of Forest Biomaterials and Technology.
    Samuelsson, Robert
    Swedish University of Agricultural Sciences, Department of Forest Biomaterials and Technology.
    Hellqvist, Sven
    Swedish University of Agricultural Sciences, Department of Forest Biomaterials and Technology.
    Öhman, Marcus
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Calcium oxide as an additive for both conservation and improvement of the combustion properties of energy grass: A preliminary study2017Inngår i: Biomass and Bioenergy, ISSN 0961-9534, E-ISSN 1873-2909, Vol. 99, s. 1-10Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Degradation of biomass is one of the major reasons for high costs of feedstock collection, transport, and storage, which is largely associated with biomass moisture and microbial activities. Our concept is to add calcium oxide (CaO) to the biomass already when it is collected and in its natural (wet) condition. When a suitable quantity of CaO is added to moistened biomass, an alkali microenvironment will be formed with a pH exceeding 9, based on the reaction CaO + H2O ↔ Ca(OH)2. As a consequence, microbial activities are largely inhibited. The Ca(OH)2 will then successively react with CO2, following the reaction Ca(OH)2 + CO2 ↔ CaCO3 + H2O. The CaCO3 will reside in the feedstock throughout the entire production chain and end up as an additive/sorbent to improve combustion by decreasing slagging. Two experiments were conducted and proved the concept works for at least reed canary grass, but, as expected, the strength of the effect was dependent on the CaO dosage and initial biomass moisture.

  • 1215.
    Xiong, Shaojun
    et al.
    Sveriges Lantbruksuniversitet.
    Burvall, Jan
    Skellefteå Kraft AB.
    Örberg, Håkan
    Sveriges Lantbruksuniversitet.
    Kalen, Gunnar
    Sveriges Lantbruksuniversitet.
    Thyrel, Mikael
    Sveriges Lantbruksuniversitet.
    Öhman, Marcus
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Boström, Dan
    Umeå universitet.
    Slagging characteristics during combustion of corn stovers with and without kaolin and calcite2008Inngår i: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 22, nr 5, s. 3465-3470Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Ash-related problems have more than occasionally been observed in biomass-fired boilers and also recently in biopellet burners. These problems can lead to reduced reliability of the combustion systems as well as bad publicity for the market. When agricultural residues are used as biofuel feedstock, slagging problems will be worse. The objectives of the present work were, therefore, to examine the effects of kaolin and calcite addition on the slagging tendency of corn stover fuel when corn stover pellets are burned in a small-scale appliance and determine the slag characteristics during combustion. Pellets with an additive/fuel ratio of 3% (dry mass) were combusted in an underfed burner (50 kW) that is installed in a boiler with 90 kW output. The choice of 3% additive/fuel ratio was based on analyses of the ash melting behavior of seven fuel mixtures that combine either 0-3% kaolin or 0-3% calcite and corn stovers. The 3% kaolin and calcite addition increased the ash melting temperature (IT) by about 100-200 °C. When the 3% kaolin or calcite was added to the corn stover raw material, the severe slagging tendency of the fuel was considerably reduced. The slag quantities from burning kaolin- and calcite-added fuels were about half and one-third, respectively, of that from nonadditive pellets. The slag deposits from the burner were characterized with scanning electron microscopy (SEM) combined with energy dispersive X-ray analysis (EDS) and X-ray diffraction (XRD). The XRD was also used to examine the chemical composition of corresponding bottom ash in the boiler. The results indicated that the reduction of slagging when using additives can be attributed to a change from relatively low melting temperature silicates to higher melting temperature silicates. For the corn stover without additives, the low melting fractions of the slag were assumed to consist mainly of potassium calcium silicate, indirectly observed as a glass by the XRD. When kaolin was added, a depletion of potassium was observed because of the extensive formation of leucite (KAlSi2O6) and the glass became dominated by calcium, aluminum, and silicon. This process was accompanied by a considerable reduction of glass amount. In the case of CaCO3 addition, however, calcium magnesium silicates formed to an extent that the glass (low melting material) finally became dominated by potassium silicate. This process was also accompanied by a substantial reduction of the amount of glass.

  • 1216.
    Xiong, Shaojun
    et al.
    Swedish University of Agricultural Sciences.
    Öhman, Marcus
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Zhang, Yufen
    Beijing Normal University.
    Lestander, Torbjörn
    Swedish University of Agricultural Sciences.
    Corn stalk ash composition and its melting (slagging) behavior during combustion2010Inngår i: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 24, nr 9, s. 4866-4871Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The objectives of this study were to determine the fuel ash composition of corn stalk samples from 23 locations in Jilin province, China, and to estimate, via laboratory and theoretical methods, their ash-melting (slagging) behavior during combustion. The ash-forming matter is in general dominated by Si, K, Ca, and Mg, although there is large variation between the samples in fuel characteristics and contents of ash-forming main elements. The results from the alkali index, the ash fusion test, and the thermochemical model calculations all indicated that the corn stalk fuel showed moderate to high slagging tendencies during combustion. However, there are large differences in predicted slagging behavior for the different samples. Samples with a low K/(Ca + Mg) ratio showed moderate ash-melting temperatures in the American Society for Testing and Materials (ASTM) test and a moderate amount of melt in the temperature range of 1000-1200 °C in the thermochemical model calculations. In the samples with a high K/(Ca + Mg) ratio, however, low ash-melting temperatures and a high amount of melt in the range of 1000-1200 °C was found in the ASTM test and in the thermochemical model calculations, respectively.

  • 1217. Yan, Jinyue
    et al.
    Ryman, Christer
    Swerea MEFOS AB.
    Grip, Carl-Erik
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Wikström, Jan-Olov
    Swerea MEFOS AB.
    Preface2006Inngår i: International Journal of Green Energy, ISSN 1543-5075, E-ISSN 1543-5083, Vol. 3, nr 2, s. 115-Artikkel i tidsskrift (Annet vitenskapelig)
  • 1218.
    Yang, Kai
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    On Harmonic Emission, Propagation and Aggregation in Wind Power Plants2015Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    The increasing use of wind energy is a global trend as part of the overall transition to a more sustainable energy system. By using modern technologies, the wind energy is converted into electric power which is transported to the consumers by means of the electric power system. The use of these technologies, in the meantime, plays a significant role in maintaining power quality in the electric power system; including positive as well as negative impacts. This thesis emphasises on harmonic distortion within a wind power plant (WPP), for a wind turbine and for the plant level.The harmonic study presented in this thesis has been based on field measurements at a few different individual wind turbines and at a second location in one WPP. In general, the levels of harmonic distortion as percentage of the turbine and WPP ratings are low. Among the frequency components, even harmonics and especially interharmonics are present at levels comparable with the levels of characteristic harmonics. The measurements show that both harmonics and interharmonics vary strongly with time. Interharmonics further show a strong dependence on the active power production of the turbine, while characteristic harmonics are independent on the power production. The even harmonics and interharmonics may excite any resonance in the collection grid or in the external grid.The origin of interharmonic emission due to power converters has been verified through a series of measurements over a two-week period. The interharmonic emission originates from the difference between the generator-side frequency and the power system frequency. A series of interharmonic frequencies are produced and they vary in accordance with the generator-side frequency. Both these interharmonic frequencies and the magnitudes are related to each other, and the theoretical relations have been confirmed through the measurements.The harmonic propagation in a collection grid has been studied by using transfer functions. Without the need to know the harmonic sources, the characteristics of harmonic propagations are quantified through transfer functions. The method has been used to estimate the total harmonic level in a WPP, by combining knowledge of the transfer function with information from harmonic emission of the individual wind turbines. The harmonic aggregation of the emission from the individual turbines towards the point of connection (PoC) has been studied as well. From the studies it was found that interharmonics show a stronger cancellation compared to harmonics, especially compared to lower-order harmonics.According to the object of interest and the harmonic propagation, a distinction has been made between primary and secondary emission. A more detailed classification of the different propagations within a WPP has been proposed. A systematic approach for harmonic studies in association with WPPs has resulted from this. The harmonic voltages and currents at any location are obtained as the superposition of the contribution from different emission sources to this specific location. This location can be either within the WPP or in the external grid. The studies presented conclude that all the contributions should be included to get a reasonable overview of the harmonic distortion in the WPP.

  • 1219.
    Yang, Kai
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Wind-turbine harmonic emissions and propagation through a wind farm2012Licentiatavhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    The increasing demand for sustainable energy is one of the driving forces behind the increasing use of wind power by means of wind-turbines in electric power systems. Modern wind turbines commonly employ variable-speed-generator technology associated with a power-electronic converter as part of the grid connection. A drawback of the use of power electronics is the presence of harmonic emissions. Consequently a systematic study on distortion from wind power installations is needed; this holds for individual wind turbines as well for complete installations.In the work, measurements and analysis of harmonic emissions were performed on a number of wind-turbines in several wind parks in Northern Sweden. The measurements on the individual wind turbines reveal that the harmonic emissions are different from each other, even for different turbines from the same manufacturer. However in general the characteristic harmonics dominate the harmonic emissions. Furthermore, a long-term measurement shows that the dominant frequencies in the emission change with time.The total emission from a wind park into the public grid is determined by the emission from individual turbines and by the properties of the wind park. To study the impact of the wind park on the propagation a ``transfer function'' method has been introduced, and applied by means of calculation and simulation. The method is based on a mathematical model that predicts the harmonic propagation from the wind turbines to the public grid in the frequency range up to 50 kHz. Applying the model to three example parks reveals that, the amplitudes at the resonance frequency are strongly dependent on the resistance of both underground cables and transformer, especially at high frequencies. In other words, the higher order harmonics are damped a lot.In conclusion, wind park harmonic emissions into the public grid are due to the combination of emission from individual wind turbines and the propagation through the collection grid.

  • 1220.
    Yang, Kai
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Measurements of Complex Harmonic Current on Two Wind turbines2014Inngår i: The Renewable Energies and Power Quality Journal (RE&PQJ), ISSN 2172-038X, E-ISSN 2172-038X, nr 12, artikkel-id 297Artikkel i tidsskrift (Fagfellevurdert)
  • 1221. Yang, Kai
    et al.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Amaris, Hortensia
    University Carlos III, Madrid.
    Alvarez, Carlos
    Energy to Quality, Madrid.
    Decompositions of harmonic propagation in wind power plant2016Inngår i: Electric power systems research, ISSN 0378-7796, E-ISSN 1873-2046, Vol. 141, s. 84-90Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This paper presents harmonic propagation in a wind power plant. The two groups of propagation are distinguished based on the harmonic sources: propagation from one individual wind turbine to other turbines and to the public grid; and propagation from the public grid to the collection grid and to individual wind turbines. The paper studies the characteristics of the different harmonic propagation paths. A case with emission from all turbines, at different production levels, and from the public grid is presented as well. Also the impact of a turbine filter on the propagation is studied. The study indicates that, resonances of a wind power plant have a significant impact on the propagation. It is also shown that harmonic studies should consider both emission originating from turbines and emission originating from the public grid. It is also shown that the filter with the turbine has a significant impact on the harmonic propagation.

  • 1222.
    Yang, Kai
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Larsson, Anders
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Aggregation and amplification of wind-turbine harmonic emission in a wind park2015Inngår i: 2015 IEEE Power & Energy Society General Meeting: 26-30 July 2015, Denver CO, Piscataway, NJ: IEEE Communications Society, 2015Konferansepaper (Annet vitenskapelig)
    Abstract [en]

    This paper presents measurements of harmonic and interharmonic current (with 5 Hz frequency resolution) in the complex plane. The complex currents are spread around a center point. For interharmonics this center corresponds with the origin of the complex plane. For integer harmonics this center is off-set from the origin. A goodness-of-fit test reveals that phase angles of most interharmonics are uniformly distributed. A Monte-Carlo simulation based on the measurements has been performed to study the aggregation of the emission from individual turbines to the public grid. Low-order integer harmonics show less cancellation compared to high-order harmonics. Interharmonics aggregate close to the square-root rule for uniform phase angles.

  • 1223.
    Yang, Kai
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Larsson, Anders
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Aggregation and Amplification of Wind-Turbine Harmonic Emission in a Wind Park2015Inngår i: IEEE Transactions on Power Delivery, ISSN 0885-8977, E-ISSN 1937-4208, Vol. 30, nr 2, s. 791-799, artikkel-id 7042349Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This paper presents measurements of harmonic and interharmonic current (with 5 Hz frequency resolution) in the complex plane. The complex currents are spread around a center point. For interharmonics this center corresponds with the origin of the complex plane. For integer harmonics this center is off-set from the origin. A goodness-of-fit test reveals that phase angles of most interharmonics are uniformly distributed. A Monte-Carlo simulation based on the measurements has been performed to study the aggregation of the emission from individual turbines to the public grid. Low-order integer harmonics show less cancellation compared to high-order harmonics. Interharmonics aggregate close to the square-root rule for uniform phase angles.

  • 1224.
    Yang, Kai
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Larsson, Anders
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Wind power harmonic aggregation of multiple turbines in power bins2014Inngår i: International Conference on Harmonics and Quality of Power. Proceedings: , s. 723-727, artikkel-id 6842922Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The paper presents current harmonic and interharmonic measurement of a Type-IV wind turbine. Characterizations and classifications have been performed with the representation of harmonics and interharmonics in a complex plane. The study of aggregations due to the summation of complex currents has been performed based on Monte-Carlo Simulation for harmonics and interharmonics. Aggregations occur less for low-order harmonics, more for high-order harmonics and most for interharmonics. Aggregations are shown to be largely independent of the produced power

  • 1225.
    Yang, Kai
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Larsson, Anders
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Wahlberg, Mats
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    A statistic study of harmonics and interharmonics at a modern wind-turbine2014Inngår i: International Conference on Harmonics and Quality of Power. Proceedings: , s. 718-722, artikkel-id 6842921Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The work presents measurements of harmonics and interharmonics from a modern wind turbine over a period of several days, using a conventional power quality monitor. A statistical study has been performed to present the characteristics of the emission during the measurement. A variation of emission has been observed, especially for interharmonics within certain low-frequency bands and for the switching frequency. Multiple relations between voltage and current components have been presented, as well as multiple relations between the emission and the active-power production. Generally, harmonics are independent of the active-power, whereas interharmonics are dependent on it.

  • 1226.
    Yang, Kai
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Larsson, Anders
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Wahlberg, Mats
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik.
    Measurements of harmonic emission versus active power from wind turbines2014Inngår i: Electric power systems research, ISSN 0378-7796, E-ISSN 1873-2046, nr 108, s. 304-314Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This paper presents harmonic measurements from three individual wind turbines (2 and 2.5MW size). Both harmonics and interharmonics have been evaluated, especially with reference to variations in the active-power production. The overall spectra reveal that, emission components may occur at any frequency and not only at odd harmonics. Interharmonics and even harmonics emitted from wind turbines are relatively high. Individual frequency components depend on the power production in dierent ways: characteristic harmonics are independent of power; interharmonics show a strong correlation with power; other harmonic and interharmonic components present various patterns. It is concluded that the power production is not the only factor determining the current emission of a wind energy conversion system.

  • 1227.
    Yang, Kai
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Wahlberg, Mats
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    A comparison study of harmonic emission measurements in four windparks2011Inngår i: 2011 IEEE Power and Energy Society General Meeting, Piscataway, NJ: IEEE Communications Society, 2011Konferansepaper (Fagfellevurdert)
    Abstract [en]

    This paper presents measurements of harmonic current emissions up till 2 kHz from four different windparks in northern Sweden, all equipped with modern power-electronics converters. The measurement results are presented in different ways, including a method to quantify the impact on the grid and a method to show the variations in the spectrum with time. The results show that there exists different dominating harmonics in different windturbines and that the magnitudes of the individual frequency components vary strongly with time. Each turbine however shows a broadband component with superimposed narrowband components. The impact on the grid, with reference to permissible levels of voltage distortion, is biggest for the interharmonic components

  • 1228.
    Yang, Kai
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Wahlberg, Mats
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Characteristic and non-characteristic harmonics from windparks2011Inngår i: Proceedings of CIRED 21st International Conference on Electricity Distribution, CIRED - Congrès International des Réseaux Electriques de Distribution, 2011, artikkel-id 0251Konferansepaper (Fagfellevurdert)
    Abstract [en]

    This paper presents measurements of harmonic current emissions up till 2 kHz from four different windparks in northern Sweden, all equipped with modern power-electronics converters. A study of the four windparks was performed interms of 95% value of harmonic current spectrum and the minimum fault-level needed to fulfil the EN 50160 requirements on voltage distortion. The results show that there exists different dominating harmonics and fault-level requirements for different windturbines. Each turbine however shows a broadband component with superimposed narrowband components. The impact on the grid, with reference to permissible levels of voltage distortion, is biggest for the interharmonic components.

  • 1229.
    Yang, Kai
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Wahlberg, Mats
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik.
    Comparison of harmonic emissions at two nodes in a windpark2012Inngår i: 15th IEEE International Conference on Harmonics and Quality of Power (ICHQP 2012), IEEE Communications Society, 2012, s. 313-319Konferansepaper (Fagfellevurdert)
    Abstract [en]

    This work presents a comparison study of measurements of power quality, with emphasis on voltage and current distortion, at two locations in the same windpark, located in northern Sweden. Emissions at both locations are compared based on both harmonics and interharmonics. A complete picture of spectrum during the measurement is presented to show the variations of emission in the windpark. Some dominating harmonics are further analyzed.

  • 1230.
    Yang, Kai
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Wahlberg, Mats
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik.
    Measurements at two different nodes of a windpark2012Inngår i: 2012 IEEE Power and Energy Society General Meeting, Piscataway, NJ: IEEE Communications Society, 2012Konferansepaper (Fagfellevurdert)
    Abstract [en]

    This paper presents measurements of power quality, with emphasis on voltage and current distortion, simultaneously at two locations in the same windpark, located in northern Sweden. Both harmonics and interharmonics components are considered in the study. Similarities and differences between voltage and current distortion are presented in this paper and possible explanations are discussed. One of the conclusions is that there is no simple relation between voltage and current distortion in a windpark.

  • 1231.
    Yang, Kai
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Wahlberg, Mats
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik.
    Measurements of four-windpark harmonic emissions in northern Sweden2012Konferansepaper (Fagfellevurdert)
    Abstract [en]

    This paper presents measurements of harmonic current emissions up till few kHz from four different wind parks in northern Sweden, all equipped with modern power-electronics converters. Measurements have been performed with 10-minute time resolution between one and several weeks. The measurement results are presented in different ways, including a method to show the variations in the harmonic emissions with time. The results show that there exists different dominating harmonics in different wind turbines and that the magnitudes of the individual frequency components vary strongly with time. Each turbine however shows a broadband component with superimposed narrowband components.

  • 1232.
    Yang, Kai
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Wahlberg, Mats
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Wind power harmonic emission versus active-power production2014Konferansepaper (Fagfellevurdert)
  • 1233.
    Yang, Kai
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Yao, Liangzhong
    Alstom Transport Information Solution.
    Theoretical emission study of windpark grids: Emission propagation between windpark and grid2011Inngår i: Proceeding of the International Conference on Electrical Power Quality and Utilisation, EPQU, Piscataway, NJ: IEEE Communications Society, 2011, s. 559-564Konferansepaper (Fagfellevurdert)
    Abstract [en]

    This paper presents the results from a theoretical study on the harmonic emission of a windpark in the frequency range up to 200 kHz. The calculations are based on the transfer function from an individual turbine to the pubic grid, expressed in the frequency domain. The model has been applied to a general windpark, for which a mathematical expression has been derived. The study provides relations between different parameters in the windpark and the transfer functions. An important conclusion from the study is that emission into the public grid is negligible for frequencies above a few kHz.

  • 1234.
    Yang, Kai
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Cundeva, S
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Wahlberg, Mats
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik.
    Harmonic emission study of individual wind turbines and a wind park2013Inngår i: The Renewable Energies and Power Quality Journal (RE&PQJ), ISSN 2172-038X, E-ISSN 2172-038X, nr 11Artikkel i tidsskrift (Fagfellevurdert)
  • 1235.
    Yang, Kai
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Cundeva, S.
    University Sts. Cyrill and Methodias, Skopje, Institute of Electroheat Faculty of Electrical Engineering and Information Technology.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Wahlberg, Mats
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Measurements of harmonic and interharmonic emission from wind power systems2014Inngår i: Russian Electrical Engineering, ISSN 1068-3712, Vol. 85, nr 12, s. 769-776Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    With increasing amounts of wind power connected, the power system is impacted in a number of ways. In this paper, the emphasis is on one of those impacts: the harmonic and interharmonic emission from wind-power installations. The emission of individual wind turbines as well as from a wind park has been studied. The spectrum as a function of active-power has been studied. Various trends of emission according to the output power have been presented. For four modern wind turbines estimations have been done on the impact on the grid for each harmonic and interharmonic subgroup. The primary emission from a complete windpark due to the emission from the turbines has been analyzed

  • 1236.
    Yang, Kai
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Cundeva, Snezana
    Institute of Electroheat Faculty of Electrical Engineering and Information Technology.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Wahlberg, Mats
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik.
    Harmonic aspects of wind-power installations2013Konferansepaper (Fagfellevurdert)
    Abstract [en]

    With increasing amounts of wind power connected, the power system is impacted in a number of ways. In this paper, the emphasis has been on one of those impacts: the harmonic emission from wind-power installations. The harmonic emission of individual wind turbines as well as from a wind park has been studied. For four modern wind turbines estimations have been done on the impact on the grid per harmonic and interharmonic group. The primary emission from complete windpark due to the emission from the turbines has been analyzed.

  • 1237.
    Yang, Kai
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Schwanz, Daphne
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Harmonic aggregation and amplification in a wind-park2015Konferansepaper (Fagfellevurdert)
    Abstract [en]

    This paper studies the harmonic emission in a wind park,using a current transfer function. The emission of anindividual wind turbine has been measured during aperiod of a few weeks covering all output productions.The wind park harmonic emission is analyzed by theaverage spectrum at the collection point. The amount ofemission of the wind park as a whole is modeled by astochastic method, based on the Monte-Carlo Simulation.The measured harmonics at wind turbines have beenanalyzed and compared with the simulated overallemission at the collection point of the wind park. Theresults will be showed by graphs and some discussionswill be made.

  • 1238.
    Yang, Yongtao
    et al.
    STRI AB.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Considering a customer dissatisfaction index in the reliability of distribution networks with distributed energy resources2008Inngår i: Proceedings of the 10th International Conference on Probabilistic Methods Applied to Power Systems: PMAPS 2008, Piscataway, NJ: IEEE Communications Society, 2008, s. 1-8Konferansepaper (Fagfellevurdert)
    Abstract [en]

    This paper proposes a new design guideline for reliability improvement of distribution networks using distributed energy resource (DER). The proposed guideline is advised to maintain CDI values of all customers under a certain pre-defined threshold value. The impact of the switching devices failure on the reliability is also considered and proper corrections are made on various threshold values within the guideline, therefore the obtained results will also be valid when considering non-ideal switching devices. The simulation results show that the guideline produces reasonably good results. Furthermore the proposed correction method for the calculation of non-ideal switching devices is validated.

  • 1239.
    Yao, Wenjun
    et al.
    State Key Laboratory of Materials-Oriented Chemical Engineering, College of Chemistry and Chemical Engineering, Nanjing University of Technology.
    Zhuang, Wei
    State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing University of Technology.
    Ji, Xiaoyan
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Chen, Jingjing
    State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing University of Technology.
    Lu, Xiaohua
    State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing University of Technology, College of Chemistry and Chemical Engineering, Nanjing University of Technology.
    Wang, Changsong
    Solid-State Synthesis of Li4Ti5O12 Whiskers from TiO2-B2016Inngår i: Materials research bulletin, ISSN 0025-5408, E-ISSN 1873-4227, Vol. 75, s. 204-210Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In this work, Li4Ti5O12 (LTO) was synthesized from the precursors of TiO2-B and anatase whiskers, respectively. The synthesized LTO whiskers from TiO2-B whiskers via a solid state reaction at 650 °C have a high degree of crystallinity with an average diameter of 300 nm. However, when anatase whiskers were used as the precursor, only particle morphology LTO was produced at 750 °C. The further analysis of the precursors, the intermediate products and the final products reveal that the crystal structure of the anatase hinders the diffusion of lithium, leading to a typical reaction-diffusion process. Under this condition, only particle morphology LTO can be produced. However, the crystal structure of the TiO2-B is easy for lithium diffusion and the process is performed in two separated steps (i.e. diffusion and reaction), which makes it possible to decrease the solid-state reaction temperature down to 650 °C and then maintain the morphologies of whiskers.

  • 1240.
    Yuan, Shengjuan
    et al.
    Key Laboratory of Material and Chemical Engineering, Nanjing Tech University, Nanjing .
    Chen, Yifeng
    Key Laboratory of Material and Chemical Engineering, Nanjing Tech University, Nanjing .
    Ji, Xiaoyan
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Yang, Zhuhong
    Key Laboratory of Material and Chemical Engineering, Nanjing Tech University, Nanjing .
    Lu, Xiaohua
    Key Laboratory of Material and Chemical Engineering, Nanjing Tech University, Nanjing .
    Experimental study of CO2 absorption in aqueous cholinium-based ionic liquids2017Inngår i: Fluid Phase Equilibria, ISSN 0378-3812, E-ISSN 1879-0224, Vol. 445, s. 14-24Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    CO2 removal (or separation) is the key step for biogas upgrading. This research aims to investigate aqueous solutions of amino acid ionic liquids to achieve effective CO2 separation. In this work, three cholinium-based amino acid ionic liquids ([Cho][AA]s) (i.e. cholinium glycinate ([Cho][Gly]), cholinium alaninate ([Cho][Ala]) and cholinium prolinate ([Cho][Pro])) were synthesized and characterized. The effect of water on the viscosity, CO2 absorption loading (m and α) and apparent absorption rate constant was systematically studied. The CO2 absorption mechanism in the aqueous solution of [Cho][Gly] was explored by 13C Nuclear Magnetic Resonance (NMR). The results demonstrate that the absorption loading (m) and viscosity increase with increasing IL concentration, while the apparent absorption rate constant decreases. The absorption loading decreased with increasing temperature. The CO2 absorption mechanism in the aqueous [Cho][Gly] solution started with the chemical reaction to form carbamate at low absorption loading (α), and followed by the hydrolysis of carbamate and CO2 hydration reaction at high absorption loading (α). Moreover, the aqueous solution with 5 wt % [Cho][Gly] showed the highest regeneration efficiency, and the absorption and regeneration performance of the aqueous solution of [Cho][Gly] was compared with commercial CO2 absorbents with promising results.

  • 1241.
    Yuan, Shengjuan
    et al.
    Key Laboratory of Material and Chemical Engineering, Nanjing Tech University, Nanjing .
    Yang, Zhuhong
    Key Laboratory of Material and Chemical Engineering, Nanjing Tech University, Nanjing .
    Ji, Xiaoyan
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Chen, Yifeng
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap. Key Laboratory of Material and Chemical Engineering, Nanjing Tech University, Nanjing .
    Sun, Yunhao
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap. Key Laboratory of Material and Chemical Engineering, Nanjing Tech University.
    Lu, Xiaohua
    Key Laboratory of Material and Chemical Engineering, Nanjing Tech University, Nanjing .
    CO2 absorption in mixed aqueous solution of MDEA and cholinium glycinate2017Inngår i: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 31, nr 7, s. 7325-7333Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A new mixed solvent system that consists of cholinium glycinate ([Cho][Gly]) and aqueous N-methyldiethanolamine (MDEA) solution was developed in this work to serve as CO2 absorbent. The equilibrium absorption was carried out to investigate the effect of solution composition, pressure and temperature on CO2 absorption performance. The effect of CO2 absorption on the viscosity of the aqueous solutions was studied, and the regeneration efficiency of the aqueous solutions was also investigated. The results showed that the CO2 absorption loading decreased with increasing [Cho][Gly] concentration and temperature, and the absorption loading strongly depended on CO2 partial pressure. The reactivity of MDEA was significantly enhanced with the addition of [Cho][Gly]. The aqueous solution with (10 wt % [Cho][Gly] + 20 wt % MDEA) showed an optimal CO2 absorption and high regeneration efficiency. Furthermore, the CO2 absorption mechanism in the aqueous [Cho][Gly]-MDEA solution was explored by 13C Nuclear Magnetic Resonance (NMR), which indicated that the CO2 absorption in the aqueous [Cho][Gly]-MDEA solution was zwitterion mechanism.

  • 1242. Zavoda, Francisc
    et al.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Rönnberg, Sarah
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    CIGRE/CIRED JWG C4.24, Power Quality and EMC Issues associated with future electricity networks: status report2016Konferansepaper (Fagfellevurdert)
  • 1243.
    Zavoda, Francisc
    et al.
    IREQ (HQ), Varennes.
    Langella, Roberto
    Second University of Naples.
    Lǎzǎroiu, George Cristian
    University Politehnica of Bucharest.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Rönnberg, Sarah
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Meyer, Jan Christian
    Technische Universitaet Dresden.
    Ciufo, Philip
    University of Wollongong.
    Power Quality in the Future Grid: Results from CIGRE/CIRED JWG C4.242016Inngår i: 2016 17th International Conference on Harmonics and Quality of Power, Piscataway, NJ, 2016, s. 931-936, artikkel-id 7783475Konferansepaper (Fagfellevurdert)
    Abstract [en]

    This paper gives a status report on activities of CIGRE/CIRED JWG C4.24. The following issues are addressed in the paper: Introduction, scope of the report and terminology; New developments in power electronics (PE); Changes in probability of interference; Microgrids and PQ; Volt-VAR control and PQ; Feeder reconfiguration and PQ; Demand side management and PQ; New measurement techniques; New mitigation.

  • 1244.
    Zavoda, Francisc
    et al.
    IREQ.
    Rönnberg, Sarah
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Bollen, Math
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Meyer, Jan
    Technical University Dresden.
    Desmet, Jan
    Ghent University.
    CIGRE/CIRED/IEEE working group C4.24 - New measurement techniques in the future grid2015Konferansepaper (Fagfellevurdert)
    Abstract [en]

    One of the issues that the joint working groupCIGRÉ/CIRED/IEEE JWG C4.24 will be addressing, isthe need in future networks for new measurementtechniques, more complex and more accurate, which willbe undergoing architecture reconfiguration (due tofeeder reconfiguration) and will be witnessing old andnew phenomena affecting the power quality. This papergives a comprehensive overview and betterunderstanding of the real challenges related tomeasurement techniques in future networks

  • 1245.
    Zeng, Lei
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Yan, Jinyue
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Policy, institutional and market barriers to the implementation of clean development mechanisms (CDM) in China2005Inngår i: International Journal of Green Energy, ISSN 1543-5075, E-ISSN 1543-5083, Vol. 2, nr 3, s. 259-271Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    China is the second largest emitter of greenhouse gases (GHG) in the world, with potentially about two thirds of total Certified Emission Reductions (CERs) for Asia on the world carbon market (Gruetter, 2002). Since 68% of its primary energy is from coal, China's average energy intensity is 7.5 times higher than the EU and 4.3 times higher than the US (EU, 2003). Therefore, introducing advanced clean technologies and management to China represents opportunities for Annex I countries to obtain low-cost CERs through CDM projects, and access to one of the largest potential energy conservation markets in the world. CDM can provide a win-win solution for both China and Annex I countries, and the Chinese government considers that the introduction of CDM projects can bring advanced energy technologies and foreign investment to China, thereby helping China's sustainable economy and generating CERs. As energy efficiency is generally low and carbon intensity is high in both China's energy supply and demand sectors, numerous options exist for cost-effective energy conservation and GHG mitigation with CDM. This paper reviews current Chinese policies and administrative and institutional settings for CDM cooperation, and discusses existing policy, institutional and other barriers in the energy market by drawing on observations and experience from previous initiatives such as Cleaner Production and energy efficiency. Some options to remove these barriers are addressed. In order to make CDM projects feasible, China's government needs to promote awareness, streamline administrative systems, and be more active in building a competitive edge in the world carbon market.

  • 1246.
    Zetterholm, Jonas
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Forest based biorefinery supply chains - Identification and evaluation of economic, CO2, and resource efficiency2018Licentiatavhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Biorefineries for production of fuels, chemicals, or materials, can bean important contribution to reach a fossil-free economy. Large-scaleforest-based biorefineries are not yet cost competitive with their fossil counterparts and it is important to identify biorefinery supply chain configurations with good economic, CO2, and biomass performance if biorefineries are to be a viable alternative to the fossil refineries.

    Several factors influence the performance of biorefinery supply chains,e.g. type of conversion process, geographical localisation, and produc-tion capacity. These aspects needs to be analysed in conjunction to identify biorefineries with good supply chain performance. There ares everal approaches to improve the performance of biorefineries, wheree.g. integration with other industries can improve the economic perfor-mance by utilisation of excess heat and by-products. From a Swedish perspective the traditional forest industry is of interest as potential host industries, due to factors such as by-product availability, opportunity for heat integration, proximity to other biomass resources, and their experience in operating large-scale biomass supply chains.

    The objectives of this work were to investigate how different supply chain configurations influence the economic, biomass, and CO2 perfor-mance of thermochemical biorefineries integrated with forest industries,as well as methods for evaluating those supply chains.

    This work shows that there is an economic benefit for integration with the traditional forest industry for thermochemical biorefineries.This is especially true when the biorefinery concept can replace cur-rent old industrial equipment on site which can significantly improvethe economic performance of the biorefinery, highlighting the role the Swedish forest industry could play to reach a cost efficient large-scale implementation of lignocellulosic biorefineries.

    The cost for biomass is a large contributor to the total cost of biore-fineries and for traditional techno-economic evaluations, the biomass prices are considered as static variables. A large-scale biorefinery will likely have an impact on the biomass market, which could lead to both changes in the biomass price, as well as changed biomass demand for other industries. A framework where this is accounted for was intro-duced, combining a techno-economic perspective for evaluating the sup-ply chain performance, with a market model which identifies changes in biomass price and allocation due to the increased biomass competition.

    The biorefinery performance can be determined from several per-spectives and system boundaries, both from a plant-level and a national perspective. To facilitate a large-scale introduction of biorefineries and  maximise the benefit from their implementations, there is a need to identify biorefinery concepts with high performance considering severa system boundaries, which has been explored in this work.

  • 1247.
    Zetterholm, Jonas
    et al.
    Department of Process Integration, Swerea MEFOS AB.
    Ji, Xiaoyan
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Sundelin, Bo
    SSAB EMEA Oxelösund.
    Martin, Peter M.
    Siemens VAI Metals Technologies.
    Wang, Chuan
    Swerea MEFOS AB, Center for Process Integration in Steelmaking, Swerea MEFOS, Luleå.
    Model Development of a Blast Furnace Stove2015Inngår i: Energy Procedia, ISSN 1876-6102, E-ISSN 1876-6102, Vol. 75, s. 1758-1765Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A large amount of energy is required in the production of steel where the preheating of blast in the hot blast stoves for iron-making is one of the most energy-intensive processes. To improve the energy efficiency it is necessary to investigate how to improve the hot blast stove operation.In this work a mathematic model for evaluating the performance of the hot blast stove was developed using a finite difference approximation to represent the heat transfer inside the stove during operation. The developed model was calibrated by using the process data from the stove V26 at SSAB Oxelösund, Sweden. As a case study, the developed model was used to simulate the effect of a new concept of OxyFuel technique to hot blast stoves. The investigation shows that,by using the OxyFuel technique, it is possible to maintain the blast temperature while removing the usage of coke oven gas. Additionally, the hot blast temperature increases while the flue gas temperature decreases, which allows for an increase of the blast temperature, leading to improved energy efficiency for the hot stove system.

  • 1248.
    Zetterholm, Jonas
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Ji, Xiaoyan
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Sundelin, Bo
    SSAB EMEA Oxelösund , SSAB Special Steels Oxelösund.
    Martin, P.M.
    Siemens VAI Metals Technologies, United States.
    Wang, C.
    Department of Process Integration, Swerea MEFOS AB.
    Dynamic modelling for the hot blast stove2017Inngår i: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 185, nr 2, s. 2142-2150Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A large amount of energy is required in the production of steel where the preheating of blast in the hot blast stoves for iron-making is one of the most energy-intensive processes. To improve the energy efficiency of the steelmaking it is necessary to investigate how to improve the hot blast stove operation.In this work a mathematic model for evaluating the performance of the hot blast stove was developed using a finite difference approximation for the heat transfer inside the stove during operation. The developed model was calibrated and validated by using the process data from hot blast stove V26 at SSABs plant in Oxelösund, Sweden. The investigation shows a good agreement between the measured and modelled data.As a case study, the developed model was used to simulate the effect of a new concept of OxyFuel technique to hot blast stoves. The investigation shows that, by using this OxyFuel technique, it is possible to maintain the blast temperature while removing the usage of coke oven gas (COG). The saved COG can be used to replace some fossil fuel, such as oil and LPG.Furthermore, the effect of the cycle time on the single stove was studied. As expected, both the hot blast and flue gas temperatures are increased when increasing the cycle time. This shows that it is a good strategy for the hot blast stove to increase the blast temperature if the stove is currently not operated with the maximum allowed flue-gas temperature. 

  • 1249.
    Zetterholm, Jonas
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Mossberg, Johanna
    RISE Research Institutes of Sweden, Bioeconomy.
    Joakim, Lundgren
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Wetterlund, Elisabeth
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Evaluating investments in integrated biofuel production - factoring in uncertainty through real options analysis2019Inngår i: PROCEEDINGS OF ECOS 2019 / [ed] Wojciech Stanek, Paweł Gładysz, Sebastian Werle, Wojciech Adamczyk, 2019, s. 1921-1932Konferansepaper (Fagfellevurdert)
    Abstract [en]

    In the endeavour to reduce CO2 emissions from the transport sector, biofuels from forest industry by-products are key. The adaptation of forest-based biorefinery technologies has so far been low which can partly be attributed to uncertainties in the form of policy instability, market prices, and technology costs. These uncertainties in combination with technology learning, which can be expected to reduce future investment costs, could make it favourable to postpone an investment decision. When applying real options theory, it is recognised that there is an opportunity cost associated with the decision to invest, since the option to wait for more favourable market conditions to occur is forfeited. In traditional discounted cash flow analysis, the impact of uncertainty and the value of reducing it (e.g. by waiting), is usually not taken into consideration. This paper uses a real options framework that incorporates the option to postpone an investment to reduce market uncertainties and wait for technology learning to occur. The focus is to investigate how the usage of an investment decision rule based on real options analysis affects technology choice, the economic performance, and when in time it is favourable to invest in pulp mill integrated biofuel production, compared with using a decision rule based on traditional discounted cash flow analysis. As an illustrative case study we examine a pulp mill which has the option, but not the obligation, to invest in either of two different biofuel production technologies that both use the pulp mill by-product black liquor as feedstock: (1) black liquor gasification followed by fuel synthesis, and (2) membrane separation of lignin followed by hydrodeoxygenation. With the usage of the real options framework and the inclusion of the uncertainties regarding future market prices and investment costs, the decision to invest is made later, compared with using traditional cash flow analysis. The usage of real options also reduces the likeliness of a net loss occurring if an investment is made, as well as increases the expected economic returns, showing the added economic value of flexibility in the face of uncertain future conditions.

  • 1250.
    Zetterholm, Jonas
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Pettersson, Karin
    RISE Research Institutes of Sweden, Eklandagatan 86, SE-412 61 Gothenburg.
    Leduc, Sylvain
    International Institute for Applied Systems Analysis (IIASA), Schlossplatz 1, A-2361 Laxenburg.
    Lundgren, Joakim
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap. International Institute for Applied Systems Analysis (IIASA), Schlossplatz 1, A-2361 Laxenburg.
    Wetterlund, Elisabeth
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap. International Institute for Applied Systems Analysis (IIASA), Schlossplatz 1, A-2361 Laxenburg.
    Resource efficiency or economy of scale: Biorefinery supply chain configurations for co-gasification of black liquor and pyrolysis liquids2018Inngår i: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 230, s. 912-924Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Biorefineries for the production of fuels, chemicals, or materials can be an important contributor to reducing dependence on fossil fuels. The economic performance of the biorefinery supply chain can be increased by, for example, industrial integration to utilise excess heat and products, increasing size to improve economy of scale, and using intermediate upgrading to reduce feedstock transport cost. To enable a large-scale introduction of biorefineries it is important to identify cost efficient supply chain configurations.

    This work investigates a lignocellulosic biorefinery concept integrated with forest industry, focusing on how different economic conditions affect the preferred supply chain configurations. The technology investigated is black liquor gasification, with and without the addition of pyrolysis liquids to increase production capacity. Primarily, it analyses trade-offs between high biomass conversion efficiency and economy of scale effects, as well as the selection of centralised vs. decentralised supply chain configurations.

    The results show the economic advantage for biomass efficient configurations, when the biorefinery investment is benefited from an alternative investment credit due to the replacement of current capital-intensive equipment at the host industry. However, the investment credit received heavily influenced the cost of the biorefinery and clearly illustrates the benefit for industrial integration to reduce the cost of biorefineries. There is a benefit for a decentralised supply chain configuration under very high biomass competition. However, for lower biomass competition, site-specific conditions will impact the favourability of either centralised or decentralised supply chain configurations.

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